Science.gov

Sample records for acquisition high bandwidth

  1. Network Bandwidth Utilization Forecast Model on High Bandwidth Network

    SciTech Connect

    Yoo, Wucherl; Sim, Alex

    2014-07-07

    With the increasing number of geographically distributed scientific collaborations and the scale of the data size growth, it has become more challenging for users to achieve the best possible network performance on a shared network. We have developed a forecast model to predict expected bandwidth utilization for high-bandwidth wide area network. The forecast model can improve the efficiency of resource utilization and scheduling data movements on high-bandwidth network to accommodate ever increasing data volume for large-scale scientific data applications. Univariate model is developed with STL and ARIMA on SNMP path utilization data. Compared with traditional approach such as Box-Jenkins methodology, our forecast model reduces computation time by 83.2percent. It also shows resilience against abrupt network usage change. The accuracy of the forecast model is within the standard deviation of the monitored measurements.

  2. High bandwidth control of precision motion instrumentation

    NASA Astrophysics Data System (ADS)

    Bristow, Douglas A.; Dong, Jingyan; Alleyne, Andrew G.; Ferreira, Placid; Salapaka, Srinivas

    2008-10-01

    This article presents a high-bandwidth control design suitable for precision motion instrumentation. Iterative learning control (ILC), a feedforward technique that uses previous iterations of the desired trajectory, is used to leverage the repetition that occurs in many tasks, such as raster scanning in microscopy. Two ILC designs are presented. The first design uses the motion system dynamic model to maximize bandwidth. The second design uses a time-varying bandwidth that is particularly useful for nonsmooth trajectories such as raster scanning. Both designs are applied to a multiaxis piezoelectric-actuated flexure system and evaluated on a nonsmooth trajectory. The ILC designs demonstrate significant bandwidth and precision improvements over the feedback controller, and the ability to achieve precision motion control at frequencies higher than multiple system resonances.

  3. High bandwidth vapor density diagnostic system

    DOEpatents

    Globig, Michael A.; Story, Thomas W.

    1992-01-01

    A high bandwidth vapor density diagnostic system for measuring the density of an atomic vapor during one or more photoionization events. The system translates the measurements from a low frequency region to a high frequency, relatively noise-free region in the spectrum to provide improved signal to noise ratio.

  4. High Bandwidth Differential Amplifier for Shock Experiments

    SciTech Connect

    Ross, P. W., Tran, V., Chau, R.

    2012-04-30

    We developed a high bandwidth differential amplifier for gas gun shock experiments/applications. The circuit has a bandwidth > 1 GHz, and is capable of measuring signals of ≤1.5 V with a common mode rejection of 250 V. Conductivity measurements of gas gun targets are measured by flowing high currents through the targets. The voltage is measured across the target using a technique similar to a four-point probe. Because of the design of the current source and load, the target voltage is approximately 250 V relative to ground. Since the expected voltage change in the target is < 1 V, the differential amplifier must have a large common mode rejection. High pass filters suppress internal ringing of operational amplifiers. Results of bench tests are shown.

  5. RAID Disk Arrays for High Bandwidth Applications

    NASA Technical Reports Server (NTRS)

    Moren, Bill

    1996-01-01

    High bandwidth applications require large amounts of data transferred to/from storage devices at extremely high data rates. Further, these applications often are 'real time' in which access to the storage device must take place on the schedule of the data source, not the storage. A good example is a satellite downlink - the volume of data is quite large and the data rates quite high (dozens of MB/sec). Further, a telemetry downlink must take place while the satellite is overhead. A storage technology which is ideally suited to these types of applications is redundant arrays of independent discs (RAID). Raid storage technology, while offering differing methodologies for a variety of applications, supports the performance and redundancy required in real-time applications. Of the various RAID levels, RAID-3 is the only one which provides high data transfer rates under all operating conditions, including after a drive failure.

  6. A high-bandwidth spintronic position sensor.

    PubMed

    Tuma, Tomas; Pantazi, Angeliki; Sahoo, Deepak R; Eib, Philipp; Salis, Gian; Pozidis, Haris; Sebastian, Abu

    2014-09-19

    Position sensing with resolution down to the scale of a single atom is of key importance in nanoscale science and engineering. However, only optical-sensing methods are currently capable of non-contact sensing at such resolution over a high bandwidth. Here, we report a new non-contact, non-optical position-sensing concept based on detecting changes in a high-gradient magnetic field of a microscale magnetic dipole by means of spintronic sensors. Experimental measurements show a sensitivity of up to 40 Ω/μm, a linear range greater than 10 μm and a noise floor of 0.5 pm/√[Hz]. Also shown is the use of the sensor for position measurements for closed-loop control of a high-speed atomic force microscope with a frame rate of more than 1 frame/s.

  7. High bandwidth magnetically isolated signal transmission circuit

    NASA Technical Reports Server (NTRS)

    Repp, John Donald (Inventor)

    2005-01-01

    Many current electronic systems incorporate expensive or sensitive electrical components. Because electrical energy is often generated or transmitted at high voltages, the power supplies to these electronic systems must be carefully designed. Power supply design must ensure that the electrical system being supplied with power is not exposed to excessive voltages or currents. In order to isolate power supplies from electrical equipment, many methods have been employed. These methods typically involve control systems or signal transfer methods. However, these methods are not always suitable because of their drawbacks. The present invention relates to transmitting information across an interface. More specifically, the present invention provides an apparatus for transmitting both AC and DC information across a high bandwidth magnetic interface with low distortion.

  8. Fast Faraday Cup With High Bandwidth

    SciTech Connect

    Deibele, Craig E

    2006-03-14

    A circuit card stripline Fast Faraday cup quantitatively measures the picosecond time structure of a charged particle beam. The stripline configuration maintains signal integrity, and stitching of the stripline increases the bandwidth. A calibration procedure ensures the measurement of the absolute charge and time structure of the charged particle beam.

  9. Novel high-bandwidth bimorph deformable mirrors

    NASA Astrophysics Data System (ADS)

    Griffith, Michael S.; Laycock, Leslie C.; Archer, Nick J.

    2004-12-01

    Adaptive Optics (AO) is a critical underpinning technology for future laser delivery (including free-space optical communications), target illumination and imaging systems. It measures and compensates for optical distortion caused by transmission through the atmosphere, resulting in the ability to deploy smaller lasers and identify targets at greater ranges. One of the key components in an AO system is the wavefront modifier, which acts on the incoming or outgoing beam to counter the effects of the atmosphere. BAE SYSTEMS Advanced Technology Centre is developing multi-element bimorph deformable mirrors for such an applications. Our initial designs were based on a standard construction and exhibited a resonant frequency of 1kHz with a maximum stroke of +/-20μm for an active aperture of 50mm. These devices were limited by the necessity to have a 'dead space' between the inner active area and the mirror boundary; this ensured that both the requirements for the stroke and the fixed boundary conditions could be met simultaneously. However, there was a significant penalty to pay in terms of bandwidth, which is inversely proportional to the square of the full mirror diameter. In a series of iteration steps, we have created novel mounting arrangements that reduce dead space and thus provide the optimum trade-off between bandwidth and stroke. These schemes include supporting the mirror from underneath, rather than at its edge. As a result, models of 60mm active diameter mirrors predict a resonance in excess of 5kHz, combined with a maximum stroke greater than +/-40μm. This paper will discuss a number of different mirror designs and present experimental results for recently assembled devices.

  10. High bandwidth deflection readout for atomic force microscopes.

    PubMed

    Steininger, Juergen; Bibl, Matthias; Yoo, Han Woong; Schitter, Georg

    2015-10-01

    This contribution presents the systematic design of a high bandwidth deflection readout mechanism for atomic force microscopes. The widely used optical beam deflection method is revised by adding a focusing lens between the cantilever and the quadrant photodetector (QPD). This allows the utilization of QPDs with a small active area resulting in an increased detection bandwidth due to the reduced junction capacitance. Furthermore the additional lens can compensate a cross talk between a compensating z-movement of the cantilever and the deflection readout. Scaling effects are analyzed to get the optimal spot size for the given geometry of the QPD. The laser power is tuned to maximize the signal to noise ratio without limiting the bandwidth by local saturation effects. The systematic approach results in a measured -3 dB detection bandwidth of 64.5 MHz at a deflection noise density of 62fm/√Hz.

  11. Delivery of very high bandwidth with ATM switches and SONET

    SciTech Connect

    Gossage, S.A.

    1993-08-01

    To deliver high bandwidth, a ubiquitous inter-/intra-building cable plant consisting of single mode and multimode fiber as well as twisted pair copper is required. The selection of the ``glue`` to transport and interconnect distributed LANs with central facility resources over a pervasive cable plant is the focus of this paper. A description of the traditional problems that must be overcome to provide very high bandwidth beyond the narrow confines of a computer center is given. The applicability of Asynchronous Transfer Mode (ATM) switching (interconnection) and Synchronous Optical NETwork (SONET) (transport) for high bandwidth delivery is described using the environment and requirements of Sandia National Laboratories. Other methods for distributing high data rates are compared and contrasted. Sandia is implementing a standards based foundation utilizing a pervasive single mode fiber cable plant, SONET transport, and ATM switching to meet the goals of gigabit networking.

  12. Lasercomm system development for high-bandwidth terrestrial communications

    NASA Astrophysics Data System (ADS)

    Juarez, Juan C.; Souza, Katherine T.; Bos, Natalie G.; Brown, Andrea M.; Cannon, Brice M.; Petrillo, Keith G.; Riggins, James L.; Sluz, Joseph E.; Tomey, Hala J.; Venkat, Radha A.

    2016-05-01

    In recent years, various terrestrial free-space optical (FSO) communications systems have been demonstrated to achieve high-bandwidth communications between mobile platforms. The terminal architectures fall into three general categories: (1) single aperture systems with tip/tilt control, (2) multi-aperture system with tip/tilt control, and (3) single aperture systems with tip/tilt control and higher order adaptive optics correction. Terrestrial modem approaches generally use direct detection receivers because they provide high bandwidth capability (0.1-10 Gbps) without the complexity of coherent detection. Modems are often augmented with a mix of forward error correction (FEC), interleaving, and/or retransmission for improved data transport. This paper will present a terminal and modem architecture for a low-SWAP FSO communications system that enables robust, high-bandwidth communications under highly scintillated links as found in terrestrial applications such as air-to-air, air-to-surface, and surface-to-surface links.

  13. High Bandwidth Communications: 2000-2004

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This custom bibliography from the NASA Scientific and Technical Information Program lists a sampling of records found in the NASA Aeronautics and Space Database. The scope of this topic includes optical and high-frequency microwave systems to enhance data transmission rates. This area of focus is one of the enabling technologies as defined by NASA s Report of the President s Commission on Implementation of United States Space Exploration Policy, published in June 2004.

  14. TDX: A high-bandwidth crossbar-switched communication paradigm

    SciTech Connect

    Pierce, P.E.; Eilers, D.L.; Schreiber, A.L.

    1994-08-01

    Digital signal processing systems under development today require scalable and reconfigurable high bandwidth communication resources between processing elements. Shared memory architectures require the ability to transfer data from one processor node to another, as well as maintaining data coherency such as provided by the Scalable Coherent Interface (SCI). Signal processing systems that must move large amounts of data between processor nodes, are best served by a communication system that allows reconfigurable streams of data to flow at deterministic rates with minimal overhead. A Time Domain Crossbar (TDX) communication system providing scalable, programmable, high-bandwidth, streaming communication has been developed and is described in this paper.

  15. High-bandwidth hybrid quantum repeater.

    PubMed

    Munro, W J; Van Meter, R; Louis, Sebastien G R; Nemoto, Kae

    2008-07-25

    We present a physical- and link-level design for the creation of entangled pairs to be used in quantum repeater applications where one can control the noise level of the initially distributed pairs. The system can tune dynamically, trading initial fidelity for success probability, from high fidelity pairs (F=0.98 or above) to moderate fidelity pairs. The same physical resources that create the long-distance entanglement are used to implement the local gates required for entanglement purification and swapping, creating a homogeneous repeater architecture. Optimizing the noise properties of the initially distributed pairs significantly improves the rate of generating long-distance Bell pairs. Finally, we discuss the performance trade-off between spatial and temporal resources.

  16. Optical interconnect technologies for high-bandwidth ICT systems

    NASA Astrophysics Data System (ADS)

    Chujo, Norio; Takai, Toshiaki; Mizushima, Akiko; Arimoto, Hideo; Matsuoka, Yasunobu; Yamashita, Hiroki; Matsushima, Naoki

    2016-03-01

    The bandwidth of information and communication technology (ICT) systems is increasing and is predicted to reach more than 10 Tb/s. However, an electrical interconnect cannot achieve such bandwidth because of its density limits. To solve this problem, we propose two types of high-density optical fiber wiring for backplanes and circuit boards such as interface boards and switch boards. One type uses routed ribbon fiber in a circuit board because it has the ability to be formed into complex shapes to avoid interfering with the LSI and electrical components on the board. The backplane is required to exhibit high density and flexibility, so the second type uses loose fiber. We developed a 9.6-Tb/s optical interconnect demonstration system using embedded optical modules, optical backplane, and optical connector in a network apparatus chassis. We achieved 25-Gb/s transmission between FPGAs via the optical backplane.

  17. Optical lightpipe as a high-bandwidth fusion diagnostic

    NASA Astrophysics Data System (ADS)

    Moran, M. J.; Lerche, R. A.; Mant, G.; Glebov, V. Yu.; Sangster, T. C.; Mack, J. M.

    2006-10-01

    A recent series of experiments at the University of Rochester Laboratory for Laser Energetics OMEGA facility studied the feasibility of using radiation-to-light converters and high-bandwidth optical signal transmission to remote recording devices as an alternate nuclear diagnostic method. A prototype system included a radiation-to-light converter, a multiple-section lightpipe consisting of stainless steel tubes with polished interiors and turning mirrors, and a streak camera or photomultiplier/digitizer combination for signal recording. Several different radiation-to-light converters (scintillators, glasses, plastics, and pressurized CO2) performed well and produced predictable optical emissions. The lightpipe transmitted high-bandwidth optical signals to the recording stations. Data were recorded with the streak camera, the photomultiplier/digitizer, and with both recorders simultaneously.

  18. The Optical Lightpipe as a High-Bandwidth Fusion Diagnostic

    SciTech Connect

    Moran, M J; Lerche, R A; Mant, G; Glebov, V Y; Sangster, T C; Mack, J M

    2006-07-21

    A recent series of experiments at the University of Rochester Laboratory for Laser Energetics OMEGA facility studied the feasibility of using radiation-to-light converters and high bandwidth optical signal transmission to remote recording devices as an alternate nuclear diagnostic method. A prototype system included a radiation-to-light converter, a multiple-section light pipe consisting of stainless steel tubes with polished interiors and turning mirrors, and a streak camera or photomultiplier/digitizer combination for signal recording. Several different radiation-to-light converters (scintillators, glasses, plastics, and pressurized CO{sub 2}) performed well and produced predictable optical emissions. The lightpipe transmitted high-bandwidth optical signals to the recording stations. Data were recorded with the streak camera, the photomultiplier/digitizer, and with both recorders simultaneously.

  19. High-Density, High-Bandwidth, Multilevel Holographic Memory

    NASA Technical Reports Server (NTRS)

    Chao, Tien-Hsin

    2008-01-01

    A proposed holographic memory system would be capable of storing data at unprecedentedly high density, and its data transfer performance in both reading and writing would be characterized by exceptionally high bandwidth. The capabilities of the proposed system would greatly exceed even those of a state-of-the art memory system, based on binary holograms (in which each pixel value represents 0 or 1), that can hold .1 terabyte of data and can support a reading or writing rate as high as 1 Gb/s. The storage capacity of the state-of-theart system cannot be increased without also increasing the volume and mass of the system. However, in principle, the storage capacity could be increased greatly, without significantly increasing the volume and mass, if multilevel holograms were used instead of binary holograms. For example, a 3-bit (8-level) hologram could store 8 terabytes, or an 8-bit (256-level) hologram could store 256 terabytes, in a system having little or no more size and mass than does the state-of-the-art 1-terabyte binary holographic memory. The proposed system would utilize multilevel holograms. The system would include lasers, imaging lenses and other beam-forming optics, a block photorefractive crystal wherein the holograms would be formed, and two multilevel spatial light modulators in the form of commercially available deformable-mirror-device spatial light modulators (DMDSLMs) made for use in high speed input conversion of data up to 12 bits. For readout, the system would also include two arrays of complementary metal oxide/semiconductor (CMOS) photodetectors matching the spatial light modulators. The system would further include a reference-beam sterring device (equivalent of a scanning mirror), containing no sliding parts, that could be either a liquid-crystal phased-array device or a microscopic mirror actuated by a high-speed microelectromechanical system. Time-multiplexing and the multilevel nature of the DMDSLM would be exploited to enable writing

  20. Managing high-bandwidth real-time data storage

    SciTech Connect

    Bigelow, David D.; Brandt, Scott A; Bent, John M; Chen, Hsing-Bung

    2009-09-23

    There exist certain systems which generate real-time data at high bandwidth, but do not necessarily require the long-term retention of that data in normal conditions. In some cases, the data may not actually be useful, and in others, there may be too much data to permanently retain in long-term storage whether it is useful or not. However, certain portions of the data may be identified as being vitally important from time to time, and must therefore be retained for further analysis or permanent storage without interrupting the ongoing collection of new data. We have developed a system, Mahanaxar, intended to address this problem. It provides quality of service guarantees for incoming real-time data streams and simultaneous access to already-recorded data on a best-effort basis utilizing any spare bandwidth. It has built in mechanisms for reliability and indexing, can scale upwards to meet increasing bandwidth requirements, and handles both small and large data elements equally well. We will show that a prototype version of this system provides better performance than a flat file (traditional filesystem) based version, particularly with regard to quality of service guarantees and hard real-time requirements.

  1. Ultra-high bandwidth quantum secured data transmission

    PubMed Central

    Dynes, James F.; Tam, Winci W-S.; Plews, Alan; Fröhlich, Bernd; Sharpe, Andrew W.; Lucamarini, Marco; Yuan, Zhiliang; Radig, Christian; Straw, Andrew; Edwards, Tim; Shields, Andrew J.

    2016-01-01

    Quantum key distribution (QKD) provides an attractive means for securing communications in optical fibre networks. However, deployment of the technology has been hampered by the frequent need for dedicated dark fibres to segregate the very weak quantum signals from conventional traffic. Up until now the coexistence of QKD with data has been limited to bandwidths that are orders of magnitude below those commonly employed in fibre optic communication networks. Using an optimised wavelength divisional multiplexing scheme, we transport QKD and the prevalent 100 Gb/s data format in the forward direction over the same fibre for the first time. We show a full quantum encryption system operating with a bandwidth of 200 Gb/s over a 100 km fibre. Exploring the ultimate limits of the technology by experimental measurements of the Raman noise, we demonstrate it is feasible to combine QKD with 10 Tb/s of data over a 50 km link. These results suggest it will be possible to integrate QKD and other quantum photonic technologies into high bandwidth data communication infrastructures, thereby allowing their widespread deployment. PMID:27734921

  2. Ultra-high bandwidth quantum secured data transmission

    NASA Astrophysics Data System (ADS)

    Dynes, James F.; Tam, Winci W.-S.; Plews, Alan; Fröhlich, Bernd; Sharpe, Andrew W.; Lucamarini, Marco; Yuan, Zhiliang; Radig, Christian; Straw, Andrew; Edwards, Tim; Shields, Andrew J.

    2016-10-01

    Quantum key distribution (QKD) provides an attractive means for securing communications in optical fibre networks. However, deployment of the technology has been hampered by the frequent need for dedicated dark fibres to segregate the very weak quantum signals from conventional traffic. Up until now the coexistence of QKD with data has been limited to bandwidths that are orders of magnitude below those commonly employed in fibre optic communication networks. Using an optimised wavelength divisional multiplexing scheme, we transport QKD and the prevalent 100 Gb/s data format in the forward direction over the same fibre for the first time. We show a full quantum encryption system operating with a bandwidth of 200 Gb/s over a 100 km fibre. Exploring the ultimate limits of the technology by experimental measurements of the Raman noise, we demonstrate it is feasible to combine QKD with 10 Tb/s of data over a 50 km link. These results suggest it will be possible to integrate QKD and other quantum photonic technologies into high bandwidth data communication infrastructures, thereby allowing their widespread deployment.

  3. High Bandwidth Electro-optic Scanner for Optical Data Storage

    NASA Astrophysics Data System (ADS)

    Zhai, Jinhui; Huang, Yuhong; Schroeck, Steve; Messner, W.; Stancil, Daniel D.; Schlesinger, T. E.

    2000-02-01

    Beam deflectors can be used as fine tracking actuators to improve track access time and data rate in future high performance optical disk drives. In this paper we report on the use of an electro-optic (EO) scanner for optical data storage. Track following has been accomplished using this EO actuator with a servo bandwidth of 200 kHz, and single-stage high-speed track switching/following has been demonstrated in a new optical head tracking system with reduced offset. A fine tracking experiment has also been demonstrated using an EO actuator with a voice coil motor (VCM) actuator to extend the fine tracking range. A new compensator design method, the PQ method, has been used for this scanner/VCM compound actuator system. Significant improvements in track switching/following speed are demonstrated with the scanner/VCM compound actuator as compared to tracking with the VCM actuator alone.

  4. Development of high frequency and wide bandwidth Johnson noise thermometry

    SciTech Connect

    Crossno, Jesse; Liu, Xiaomeng; Kim, Philip; Ohki, Thomas A.; Fong, Kin Chung

    2015-01-12

    We develop a high frequency, wide bandwidth radiometer operating at room temperature, which augments the traditional technique of Johnson noise thermometry for nanoscale thermal transport studies. Employing low noise amplifiers and an analog multiplier operating at 2 GHz, auto- and cross-correlated Johnson noise measurements are performed in the temperature range of 3 to 300 K, achieving a sensitivity of 5.5 mK (110 ppm) in 1 s of integration time. This setup allows us to measure the thermal conductance of a boron nitride encapsulated monolayer graphene device over a wide temperature range. Our data show a high power law (T ∼ 4) deviation from the Wiedemann-Franz law above T ∼ 100 K.

  5. Fudge: a high-bandwidth fusion diagnostic of the NIF

    SciTech Connect

    Moran, M. J., LLNL

    1998-06-02

    Diagnostics for the National Ignition Facility (NIF)/Inertial Confinement Fusion (ICF) program must include good characterization of the fusion source. Ideally, diagnostics would measure the spatially-resolved history of the fusion reaction rate and temperature. Existing diagnostics can satisfy this goal only partially. One class of new techniques that could play a major role in high-yield diagnostics is measurements based on fusion {gamma} rays. The Fusion Diagnostic Gamma Experiment (FUDGE) can be used to perform energy-resolved measurements of (D,T) fusion reaction rates This diagnostic is based on the 16 7-MeV {gamma} rays that are produced by (D,T) fusion. The {gamma} rays are free of spectral dispersion and can be detected with a high bandwidth Cherenkov detector. A simple magnetic monochromator selects signals from the 16 7-MeV {gamma} rays and reduces background signals from non-fusion {gamma} rays.

  6. High-bandwidth continuous-flow arc furnace

    DOEpatents

    Hardt, David E.; Lee, Steven G.

    1996-01-01

    A high-bandwidth continuous-flow arc furnace for stream welding applications includes a metal mass contained in a crucible having an orifice. A power source charges an electrode for generating an arc between the electrode and the mass. The arc heats the metal mass to a molten state. A pressurized gas source propels the molten metal mass through the crucible orifice in a continuous stream. As the metal is ejected, a metal feeder replenishes the molten metal bath. A control system regulates the electrode current, shielding gas pressure, and metal source to provide a continuous flow of molten metal at the crucible orifice. Independent control over the electrode current and shield gas pressure decouples the metal flow temperature and the molten metal flow rate, improving control over resultant weld characteristics.

  7. High-bandwidth continuous-flow arc furnace

    DOEpatents

    Hardt, D.E.; Lee, S.G.

    1996-08-06

    A high-bandwidth continuous-flow arc furnace for stream welding applications includes a metal mass contained in a crucible having an orifice. A power source charges an electrode for generating an arc between the electrode and the mass. The arc heats the metal mass to a molten state. A pressurized gas source propels the molten metal mass through the crucible orifice in a continuous stream. As the metal is ejected, a metal feeder replenishes the molten metal bath. A control system regulates the electrode current, shielding gas pressure, and metal source to provide a continuous flow of molten metal at the crucible orifice. Independent control over the electrode current and shield gas pressure decouples the metal flow temperature and the molten metal flow rate, improving control over resultant weld characteristics. 4 figs.

  8. High Bandwidth Short Stroke Rotary Fast Tool Servo

    SciTech Connect

    Montesanti, R C; Trumper, D L

    2003-08-22

    This paper presents the design and performance of a new rotary fast tool servo (FTS) capable of developing the 40 g's tool tip acceleration required to follow a 5 micron PV sinusoidal surface at 2 kHz with a planned accuracy of 50 nm, and having a full stroke of 50 micron PV at lower frequencies. Tests with de-rated power supplies have demonstrated a closed-loop unity-gain bandwidth of 2 kHz with 20 g's tool acceleration, and we expect to achieve 40 g's with supplies providing {+-} 16 Amp to the Lorentz force actuator. The use of a fast tool servo with a diamond turning machine for producing non-axisymmetric or textured surfaces on a workpiece is well known. Our new rotary FTS was designed to specifically accommodate fabricating prescription textured surfaces on 5 mm diameter spherical target components for High Energy Density Physics experiments on the National Ignition Facility Laser (NIF).

  9. A neural amplifier with high programmable gain and tunable bandwidth.

    PubMed

    Perlin, Gayatri E; Sodagar, Amir M; Wise, Kensall D

    2008-01-01

    A neural recording amplifier having programmable gain and bandwidth is presented. The gain can be digitally programmed using 6 bits from 100x to 1100x in steps of 100x. The low-frequency cutoff can be varied from less than 10Hz to above 100Hz to accept or reject field potentials while the high-frequency cutoff is fixed at 9kHz. The input referred noise of this amplifier is 4.8microV(rms) and it consumes 50microW operating from +/-1.5V. Implemented in a 0.5microm technology, the amplifier occupies an area of 0.098mm(2). This amplifier has been successfully demonstrated in-vivo and compared to a commercial amplifier.

  10. High Bandwidth Optical Links for Micro-Satellite Support

    NASA Technical Reports Server (NTRS)

    Chao, Tien-Hsin (Inventor); Wilson, Keith E. (Inventor); Coste, Keith (Inventor)

    2016-01-01

    A method, systems, apparatus and device enable high bandwidth satellite communications. An onboard tracking detector, installed in a low-earth orbit satellite, detects a position of an incoming optical beam received/transmitted from a first ground station of one or more ground stations. Tracker electronics determine orientation information of the incoming optical beam based on the position. Control electronics receive the orientation information from the tracker electronics, and control a waveguide drive electronics. The waveguide drive electronics control a voltage that is provided to an electro-optic waveguide beam steering device. The electro-optic waveguide beam steering device steers an outgoing optical beam to one of the one or more ground stations based on the voltage.

  11. High bandwidth synaptic communication and frequency tracking in human neocortex.

    PubMed

    Testa-Silva, Guilherme; Verhoog, Matthijs B; Linaro, Daniele; de Kock, Christiaan P J; Baayen, Johannes C; Meredith, Rhiannon M; De Zeeuw, Chris I; Giugliano, Michele; Mansvelder, Huibert D

    2014-11-01

    Neuronal firing, synaptic transmission, and its plasticity form the building blocks for processing and storage of information in the brain. It is unknown whether adult human synapses are more efficient in transferring information between neurons than rodent synapses. To test this, we recorded from connected pairs of pyramidal neurons in acute brain slices of adult human and mouse temporal cortex and probed the dynamical properties of use-dependent plasticity. We found that human synaptic connections were purely depressing and that they recovered three to four times more swiftly from depression than synapses in rodent neocortex. Thereby, during realistic spike trains, the temporal resolution of synaptic information exchange in human synapses substantially surpasses that in mice. Using information theory, we calculate that information transfer between human pyramidal neurons exceeds that of mouse pyramidal neurons by four to nine times, well into the beta and gamma frequency range. In addition, we found that human principal cells tracked fine temporal features, conveyed in received synaptic inputs, at a wider bandwidth than for rodents. Action potential firing probability was reliably phase-locked to input transients up to 1,000 cycles/s because of a steep onset of action potentials in human pyramidal neurons during spike trains, unlike in rodent neurons. Our data show that, in contrast to the widely held views of limited information transfer in rodent depressing synapses, fast recovering synapses of human neurons can actually transfer substantial amounts of information during spike trains. In addition, human pyramidal neurons are equipped to encode high synaptic information content. Thus, adult human cortical microcircuits relay information at a wider bandwidth than rodent microcircuits.

  12. Social value of high bandwidth networks: creative performance and education.

    PubMed

    Mansell, Robin; Foresta, Don

    2016-03-01

    This paper considers limitations of existing network technologies for distributed theatrical performance in the creative arts and for symmetrical real-time interaction in online learning environments. It examines the experience of a multidisciplinary research consortium that aimed to introduce a solution to latency and other network problems experienced by users in these sectors. The solution builds on the Multicast protocol, Access Grid, an environment supported by very high bandwidth networks. The solution is intended to offer high-quality image and sound, interaction with other network platforms, maximum user control of multipoint transmissions, and open programming tools that are flexible and modifiable for specific uses. A case study is presented drawing upon an extended period of participant observation by the authors. This provides a basis for an examination of the challenges of promoting technological innovation in a multidisciplinary project. We highlight the kinds of technical advances and cultural and organizational changes that would be required to meet demanding quality standards, the way a research consortium planned to engage in experimentation and learning, and factors making it difficult to achieve an open platform that is responsive to the needs of users in the creative arts and education sectors.

  13. High bandwidth piezoresistive force probes with integrated thermal actuation

    PubMed Central

    Doll, Joseph C.; Pruitt, Beth L.

    2012-01-01

    We present high-speed force probes with on-chip actuation and sensing for the measurement of pN-scale forces at the microsecond time scale. We achieve a high resonant frequency in water (1–100 kHz) with requisite low spring constants (0.3–40 pN/nm) and low integrated force noise (1–100 pN) by targeting probe dimensions on the order of 300 nm thick, 1–2 μm wide and 30–200 μm long. Forces are measured using silicon piezoresistors while the probes are actuated thermally with an aluminum unimorph and silicon heater. The piezoresistive sensors are designed using open source numerical optimization code that incorporates constraints on operating temperature. Parylene passivation enables operation in ionic media and we demonstrate simultaneous actuation and sensing. The improved design and fabrication techniques that we describe enable a 10–20 fold improvement in force resolution or measurement bandwidth over prior piezoresistive cantilevers of comparable thickness. PMID:23175616

  14. Social value of high bandwidth networks: creative performance and education.

    PubMed

    Mansell, Robin; Foresta, Don

    2016-03-01

    This paper considers limitations of existing network technologies for distributed theatrical performance in the creative arts and for symmetrical real-time interaction in online learning environments. It examines the experience of a multidisciplinary research consortium that aimed to introduce a solution to latency and other network problems experienced by users in these sectors. The solution builds on the Multicast protocol, Access Grid, an environment supported by very high bandwidth networks. The solution is intended to offer high-quality image and sound, interaction with other network platforms, maximum user control of multipoint transmissions, and open programming tools that are flexible and modifiable for specific uses. A case study is presented drawing upon an extended period of participant observation by the authors. This provides a basis for an examination of the challenges of promoting technological innovation in a multidisciplinary project. We highlight the kinds of technical advances and cultural and organizational changes that would be required to meet demanding quality standards, the way a research consortium planned to engage in experimentation and learning, and factors making it difficult to achieve an open platform that is responsive to the needs of users in the creative arts and education sectors. PMID:26809576

  15. High-bandwidth protein analysis using solid-state nanopores.

    PubMed

    Larkin, Joseph; Henley, Robert Y; Muthukumar, Murugappan; Rosenstein, Jacob K; Wanunu, Meni

    2014-02-01

    High-bandwidth measurements of the ion current through hafnium oxide and silicon nitride nanopores allow the analysis of sub-30 kD protein molecules with unprecedented time resolution and detection efficiency. Measured capture rates suggest that at moderate transmembrane bias values, a substantial fraction of protein translocation events are detected. Our dwell-time resolution of 2.5 μs enables translocation time distributions to be fit to a first-passage time distribution derived from a 1D diffusion-drift model. The fits yield drift velocities that scale linearly with voltage, consistent with an electrophoretic process. Further, protein diffusion constants (D) are lower than the bulk diffusion constants (D0) by a factor of ~50, and are voltage-independent in the regime tested. We reason that deviations of D from D0 are a result of confinement-driven pore/protein interactions, previously observed in porous systems. A straightforward Kramers model for this inhibited diffusion points to 9- to 12-kJ/mol interactions of the proteins with the nanopore. Reduction of μ and D are found to be material-dependent. Comparison of current-blockage levels of each protein yields volumetric information for the two proteins that is in good agreement with dynamic light scattering measurements. Finally, detection of a protein-protein complex is achieved.

  16. Obtaining structural information of small proteins using solid-state nanopores and high-bandwidth measurements

    NASA Astrophysics Data System (ADS)

    Niedzwiecki, David; Lanci, Christopher; Saven, Jeffery; Drndic, Marija

    2015-03-01

    The use of biological nanopores sensors to characterize proteins has proved a fruitful field of study. Solid-state nanopores hold several advantages over their biological counterparts, including the ability to tune pore diameter and their robustness to external conditions. Despite these advantages, the use of solid-state nanopores for protein analysis has proved difficult due to rapid translocation times of proteins and poor signal-to-noise of small peptides. Recently, improvements in high-bandwidth acquisition and in signal-to-noise have made the study of small peptides using solid-state nanopores feasible. Here we report on the detection and characterization of peptides as small as 33 amino-acids in length using sub-10 nm thin silicon nitride nanopores, giving high signal levels, combined with high-bandwidth electronics. In addition we show differentiation between monomers and dimer forms of the GCN-4 p1 leucine zipper, a coil-coil structure, and compare this with the unstructured 33-mer. The differentiation between these two forms demonstrates the possibility of extracting useful structural information from short peptide structures using modern solid-state nanopore systems.

  17. High current, high bandwidth laser diode current driver

    NASA Technical Reports Server (NTRS)

    Copeland, David J.; Zimmerman, Robert K., Jr.

    1991-01-01

    A laser diode current driver has been developed for free space laser communications. The driver provides 300 mA peak modulation current and exhibits an optical risetime of less than 400 ps. The current and optical pulses are well behaved and show minimal ringing. The driver is well suited for QPPM modulation at data rates up to 440 Mbit/s. Much previous work has championed current steering circuits; in contrast, the present driver is a single-ended on/off switch. This results in twice the power efficiency as a current steering driver. The driver electrical efficiency for QPPM data is 34 percent. The high speed switch is realized with a Ku-band GaAsFET transistor, with a suitable pre-drive circuit, on a hybrid microcircuit adjacent to the laser diode.

  18. Impact of ionosphere on high-bandwidth chirp in L-band SAR and its mitigation

    NASA Astrophysics Data System (ADS)

    Nandy, Partha Sarathi; Putrevu, Deepak

    2016-05-01

    There is a trend of SAR imaging at low frequencies (VHF/UHF, L-band) and wide bandwidth, for penetration into foliage for high resolution applications. The propagation of spaceborne radar signals operating at L-band frequency or below can be seriously affected by the ionosphere. While these effects are negligible at X-band, Faraday Rotation and the frequency-dependent path delays can become seriously problematic at L-band. Range delay, interferometric phase bias, range defocussing and Faraday rotation are the most prominent ones. Due to ionospheric effects, blind use of a generic matched filter causes inaccuracies when correlating the received signal with transmitted replica. In this paper we study the effects of frequency dependent path delays in L-band SAR chirp signal due to ionospheric electron density. Also a method to correct ionospheric anomalies without the knowledge of electron content level in a single SAR acquisition is proposed.

  19. High resolution data acquisition

    DOEpatents

    Thornton, Glenn W.; Fuller, Kenneth R.

    1993-01-01

    A high resolution event interval timing system measures short time intervals such as occur in high energy physics or laser ranging. Timing is provided from a clock (38) pulse train (37) and analog circuitry (44) for generating a triangular wave (46) synchronously with the pulse train (37). The triangular wave (46) has an amplitude and slope functionally related to the time elapsed during each clock pulse in the train. A converter (18, 32) forms a first digital value of the amplitude and slope of the triangle wave at the start of the event interval and a second digital value of the amplitude and slope of the triangle wave at the end of the event interval. A counter (26) counts the clock pulse train (37) during the interval to form a gross event interval time. A computer (52) then combines the gross event interval time and the first and second digital values to output a high resolution value for the event interval.

  20. High resolution data acquisition

    DOEpatents

    Thornton, G.W.; Fuller, K.R.

    1993-04-06

    A high resolution event interval timing system measures short time intervals such as occur in high energy physics or laser ranging. Timing is provided from a clock, pulse train, and analog circuitry for generating a triangular wave synchronously with the pulse train (as seen in diagram on patent). The triangular wave has an amplitude and slope functionally related to the time elapsed during each clock pulse in the train. A converter forms a first digital value of the amplitude and slope of the triangle wave at the start of the event interval and a second digital value of the amplitude and slope of the triangle wave at the end of the event interval. A counter counts the clock pulse train during the interval to form a gross event interval time. A computer then combines the gross event interval time and the first and second digital values to output a high resolution value for the event interval.

  1. Got Bandwidth?

    ERIC Educational Resources Information Center

    Villano, Matt

    2009-01-01

    Video-heavy distance learning programs can put a strain on the campus network. This article describes how three institutions are managing bandwidth to ensure high-quality service for eLearning students.

  2. The Development and Optimisation of High Bandwidth Bimorph Deformable Mirrors

    NASA Astrophysics Data System (ADS)

    Rowe, D.; Laycock, L.; Griffith, M.; Archer, N.

    Our first mirror designs were based on a standard bimorph construction and exhibited a resonant frequency of 1 kHz with a maximum stroke of ±5 μm. These devices were limited by the requirement to have a "dead space" between the inner active area and the mirror boundary. This was necessary to ensure that the requirements for both the stroke and the static boundary conditions at the edge of the mirror could be met simultaneously, but there was a significant penalty to pay in terms of bandwidth, which is inversely proportional to the square of the full mirror diameter. In a series of design iteration steps, we have created mounting arrangements that seek not only to reduce dead space, but also to improve ruggedness and temperature stability through the use of a repeatable and reliable assembly procedure. As a result, the most recently modeled mirrors display a resonance in excess of 5 kHz, combined with a maximum stroke in excess of ±10 μm. This has been achieved by virtually eliminating the "dead space" around the mirror. By careful thermal matching of the mirror and piezoelectric substrates, operation over a wide temperature range is possible. This paper will discuss the outcomes from the design study and present our initial experimental results for the most recently assembled mirror.

  3. High bandwidth based on a tapped delay line equalization in visible light communications

    NASA Astrophysics Data System (ADS)

    Zhang, Minglun; Guo, Xujing; Zhu, Hetian; Wang, Chao; Bai, Xiaonan; Zhai, Xiangwen

    2015-08-01

    In the visible light communication, the white LED bandwidth severely limits the transmission rate of information. This paper presents an analog pre-equalization technology to compensate for the bandwidth of white LED. The technology not only can debug according to the actual channel changing, but also avoid the high costs of using FPGA technology. The pre-equalization technology is implemented by an analog circuit of tapped-delay-line, in the circuit we select an appropriate delay line and a digital to analog converter. In our LED visible light communication system, we can achieve a bandwidth of 150MHz which was proved theoretically in the paper.

  4. Design and Implementation of a Characterization Test Rig for Evaluating High Bandwidth Liquid Fuel Flow Modulators

    NASA Technical Reports Server (NTRS)

    Saus, Joseph R.; Chang, Clarence T.; DeLaat, John C.; Vrnak, Daniel R.

    2010-01-01

    A test rig was designed and developed at the NASA Glenn Research Center (GRC) for the purpose of characterizing high bandwidth liquid fuel flow modulator candidates to determine their suitability for combustion instability control research. The test rig is capable of testing flow modulators at up to 600 psia supply pressure and flows of up to 2 gpm. The rig is designed to provide a quiescent flow into the test section in order to isolate the dynamic flow modulations produced by the test article. Both the fuel injector orifice downstream of the test article and the combustor are emulated. The effect of fuel delivery line lengths on modulator dynamic performance can be observed and modified to replicate actual fuel delivery systems. For simplicity, water is currently used as the working fluid, although future plans are to use jet fuel. The rig is instrumented for dynamic pressures and flows and a high-speed data system is used for dynamic data acquisition. Preliminary results have been obtained for one candidate flow modulator.

  5. High-repetition-rate high-power variable-bandwidth dye laser

    SciTech Connect

    Lavi, S.; Amit, M.; Bialolanker, G.; Miron, E.; Levin, L.A.

    1985-07-01

    An efficient high-repetition-rate dye laser is described which has a bandwidth that can be tailored to match typical atomic inhomogeneous linewidths. The dye laser is pumped by a 4-kHz 2--6 mJ/pulse copper vapor laser. The total efficiency of the dye laser (oscillator and amplifier) is 45% for rhodamine 6G and 30% for rhodamine B.

  6. High-bandwidth, high-dynamic-range, analog optical guided-wave systems for physics instrumentation

    NASA Astrophysics Data System (ADS)

    Lowry, M.; Haigh, R.; Hugenberg, K.; Masquelier, D.; McConaghy, C.; McCammon, K.; Nelson, D.; Roeske, F.

    1992-07-01

    Two remote measurement systems that efficiently exploit the information transmission capacity of optical guided-wave technology are developed. The first system, which operates at 820 nm, was developed for nuclear weapons measurements and emphasizes high-bandwidth high-dynamic range information transmission. The second system was developed for the detector readout at the Super-Conducting Super Collider (SSC); this system emphasizes high charge sensitivity measurement transmission and operates at 1320 nm. Most of the component design (including modeling), fabrication, packaging, characterization, and system integration was done at Lawrence Livermore National Laboratory (LLNL) specifically for these specialized physics measurements applications.

  7. High-bandwidth, high-dynamic-range, analog optical guided-wave systems for physics instrumentation

    SciTech Connect

    Lowry, M.; Haigh, R.; Hugenberg, K.; Masquelier, D.; McConaghy, C.; McCammon, K.; Nelson, D.; Roeske, F.

    1992-07-01

    We have developed two remote measurement systems that efficiently exploit the information transmission capacity of optical guided-wave technology. The first system, which operates at 820 nm, was developed for nuclear weapons measurements and emphasizes high-bandwidth high-dynamic range information transmission. The second system was developed for the detector readout at the Super-Conducting Super Collider (SSC); this system emphasizes high charge sensitivity measurement transmission and operates at 1320 nm. Most of the component design (including modeling), fabrication, packaging, characterization, and system integration was done at LLNL specifically for these specialized physics measurements applications.

  8. Wide-bandwidth high-resolution search for extraterrestrial intelligence

    NASA Technical Reports Server (NTRS)

    Horowitz, Paul

    1993-01-01

    Research accomplished during the third 6-month period is summarized. Research covered the following: dual-horn antenna performance; high electron mobility transistors (HEMT) low-noise amplifiers; downconverters; fast Fourier transform (FFT) array; and backend 'feature recognizer' array.

  9. An impact excitation system for repeatable, high-bandwidth modal testing of miniature structures

    NASA Astrophysics Data System (ADS)

    Bediz, Bekir; Korkmaz, Emrullah; Burak Ozdoganlar, O.

    2014-06-01

    Miniature components and devices are increasingly seen in a myriad of applications. In general, the dynamic behavior of miniature devices is critical to their functionality and performance. However, modal testing of miniature structures poses many challenges. This paper presents a design and evaluation of an impact excitation system (IES) for repeatable, high-bandwidth, controlled-force modal testing of miniature structures. Furthermore, a dynamic model of the system is derived and experimentally validated to enable the identification of the system parameters that yield single-hit impacts with desired bandwidth and force magnitude. The system includes a small instrumented impact tip attached to a custom designed flexure-based body, an automated electromagnetic release mechanism, and various precision positioners. The excitation bandwidth and the impact force magnitude can be controlled by selecting the system parameters. The dynamic model of the system includes the structural dynamics of the flexure-based body, the electromagnetic force and the associated eddy-current damping, and the impact event. A validation study showed an excellent match between the model simulations and experiments in terms of impact force and bandwidth. The model is then used to create process maps that relate the system parameters to the number of hits (single vs. multiple), the impact force magnitudes and the excitation bandwidths. These process maps can be used to select system parameters or predict system response for a given set of parameters. A set of experiments is conducted to compare the performances of the IES and a (manual) miniature impact hammer. It is concluded that the IES significantly improves repeatability in terms of the impact bandwidth, location, and force magnitude, while providing a high excitation-bandwidth and excellent coherence values. The application of the IES is demonstrated through modal testing of a miniature contact-probe system.

  10. Fully Controllable Pancharatnam-Berry Metasurface Array with High Conversion Efficiency and Broad Bandwidth

    PubMed Central

    Liu, Chuanbao; Bai, Yang; Zhao, Qian; Yang, Yihao; Chen, Hongsheng; Zhou, Ji; Qiao, Lijie

    2016-01-01

    Metasurfaces have powerful abilities to manipulate the properties of electromagnetic waves flexibly, especially the modulation of polarization state for both linearly polarized (LP) and circularly polarized (CP) waves. However, the transmission efficiency of cross-polarization conversion by a single-layer metasurface has a low theoretical upper limit of 25% and the bandwidth is usually narrow, which cannot be resolved by their simple additions. Here, we efficiently manipulate polarization coupling in multilayer metasurface to promote the transmission of cross-polarization by Fabry-Perot resonance, so that a high conversion coefficient of 80–90% of CP wave is achieved within a broad bandwidth in the metasurface with C-shaped scatters by theoretical calculation, numerical simulation and experiments. Further, fully controlling Pancharatnam-Berry phase enables to realize polarized beam splitter, which is demonstrated to produce abnormal transmission with high conversion efficiency and broad bandwidth. PMID:27703254

  11. Fully Controllable Pancharatnam-Berry Metasurface Array with High Conversion Efficiency and Broad Bandwidth

    NASA Astrophysics Data System (ADS)

    Liu, Chuanbao; Bai, Yang; Zhao, Qian; Yang, Yihao; Chen, Hongsheng; Zhou, Ji; Qiao, Lijie

    2016-10-01

    Metasurfaces have powerful abilities to manipulate the properties of electromagnetic waves flexibly, especially the modulation of polarization state for both linearly polarized (LP) and circularly polarized (CP) waves. However, the transmission efficiency of cross-polarization conversion by a single-layer metasurface has a low theoretical upper limit of 25% and the bandwidth is usually narrow, which cannot be resolved by their simple additions. Here, we efficiently manipulate polarization coupling in multilayer metasurface to promote the transmission of cross-polarization by Fabry-Perot resonance, so that a high conversion coefficient of 80–90% of CP wave is achieved within a broad bandwidth in the metasurface with C-shaped scatters by theoretical calculation, numerical simulation and experiments. Further, fully controlling Pancharatnam-Berry phase enables to realize polarized beam splitter, which is demonstrated to produce abnormal transmission with high conversion efficiency and broad bandwidth.

  12. Using the Sirocco File System for high-bandwidth checkpoints.

    SciTech Connect

    Klundt, Ruth Ann; Curry, Matthew L.; Ward, H. Lee

    2012-02-01

    The Sirocco File System, a file system for exascale under active development, is designed to allow the storage software to maximize quality of service through increased flexibility and local decision-making. By allowing the storage system to manage a range of storage targets that have varying speeds and capacities, the system can increase the speed and surety of storage to the application. We instrument CTH to use a group of RAM-based Sirocco storage servers allocated within the job as a high-performance storage tier to accept checkpoints, allowing computation to potentially continue asynchronously of checkpoint migration to slower, more permanent storage. The result is a 10-60x speedup in constructing and moving checkpoint data from the compute nodes. This demonstration of early Sirocco functionality shows a significant benefit for a real I/O workload, checkpointing, in a real application, CTH. By running Sirocco storage servers within a job as RAM-only stores, CTH was able to store checkpoints 10-60x faster than storing to PanFS, allowing the job to continue computing sooner. While this prototype did not include automatic data migration, the checkpoint was available to be pushed or pulled to disk-based storage as needed after the compute nodes continued computing. Future developments include the ability to dynamically spawn Sirocco nodes to absorb checkpoints, expanding this mechanism to other fast tiers of storage like flash memory, and sharing of dynamic Sirocco nodes between multiple jobs as needed.

  13. High-bandwidth polymer in-line fiber modulator

    NASA Astrophysics Data System (ADS)

    Knoesen, Andre; Hamilton, Scott A.; Yankelevich, Diego R.; Weverka, Robert T.; Hill, Richard A.; Bjorklund, Gary C.

    1997-10-01

    We are developing a traveling electro-optic modulator for analog microwave modulated fiber optic links used in radar applications. The modulator is a polymer in-line fiber device that has a rugged and low loss interface to single mode fibers and can be engineered to provide linear modulation over a large dynamic range. In the development of the modulator we take advantage of a variety properties available in polymers. The ability to deposit a conformal electro-optic thin film is used to fill the gaps between high-frequency co-planar electrodes and thus obtain a good overlap between the electric field produced by the the microwave electrodes and the fields in the optical fiber and the electro-optic waveguide. Reactive ion etching of the electro-optic polymer is used to trim the thickness of the polymer waveguide to obtain operation at a specific wavelength. The thermo-optic effect is used to fine tune the operation point of the modulator to obtain a large dynamic range. The geometry of the modulator permits operation close to the absorption peak of the electro-optic polymer and this provides the opportunity to take advantage of the resonant enhancement of the nonlinearity in the vicinity of an absorption band.

  14. Wide-bandwidth high-resolution search for extraterrestrial intelligence

    NASA Technical Reports Server (NTRS)

    Horowitz, Paul

    1995-01-01

    Research was accomplished during the third year of the grant on: BETA architecture, an FFT array, a feature extractor, the Pentium array and workstation, and a radio astronomy spectrometer. The BETA (this SETI project) system architecture has been evolving generally in the direction of greater robustness against terrestrial interference. The new design adds a powerful state-memory feature, multiple simultaneous thresholds, and the ability to integrate multiple spectra in a flexible state-machine architecture. The FFT array is reported with regards to its hardware verification, array production, and control. The feature extractor is responsible for maintaining a moving baseline, recognizing large spectral peaks, following the progress of previously identified interesting spectral regions, and blocking signals from regions previously identified as containing interference. The Pentium array consists of 21 Pentium-based PC motherboards, each with 16 MByte of RAM and an Ethernet interface. Each motherboard receives and processes the data from a feature extractor/correlator board set, passing on the results of a first analysis to the central Unix workstation (through which each is also booted). The radio astronomy spectrometer is a technological spinoff from SETI work. It is proposed to be a combined spectrometer and power-accumulator, for use at Arecibo Observatory to search for neutral hydrogen emission from condensations of neutral hydrogen at high redshift (z = 5).

  15. Quick Vegas: Improving Performance of TCP Vegas for High Bandwidth-Delay Product Networks

    NASA Astrophysics Data System (ADS)

    Chan, Yi-Cheng; Lin, Chia-Liang; Ho, Cheng-Yuan

    An important issue in designing a TCP congestion control algorithm is that it should allow the protocol to quickly adjust the end-to-end communication rate to the bandwidth on the bottleneck link. However, the TCP congestion control may function poorly in high bandwidth-delay product networks because of its slow response with large congestion windows. In this paper, we propose an enhanced version of TCP Vegas called Quick Vegas, in which we present an efficient congestion window control algorithm for a TCP source. Our algorithm improves the slow-start and congestion avoidance techniques of original Vegas. Simulation results show that Quick Vegas significantly improves the performance of connections as well as remaining fair when the bandwidth-delay product increases.

  16. High efficiency and broad bandwidth grating coupler between nanophotonic waveguide and fibre

    NASA Astrophysics Data System (ADS)

    Zhu, Yu; Xu, Xue-Jun; Li, Zhi-Yong; Zhou, Liang; Han, Wei-Hua; Fan, Zhong-Chao; Yu, Yu-De; Yu, Jin-Zhong

    2010-01-01

    A high efficiency and broad bandwidth grating coupler between a silicon-on-insulator (SOI) nanophotonic waveguide and fibre is designed and fabricated. Coupling efficiencies of 46% and 25% at a wavelength of 1.55 μm are achieved by simulation and experiment, respectively. An optical 3 dB bandwidth of 45 nm from 1530 nm to 1575 nm is also obtained in experiment. Numerical calculation shows that a tolerance to fabrication error of 10 nm in etch depth is achievable. The measurement results indicate that the alignment error of ±2 μm results in less than 1 dB additional coupling loss.

  17. System identification requirements for high-bandwidth rotorcraft flight control system design

    NASA Technical Reports Server (NTRS)

    Tischler, Mark B.

    1991-01-01

    The application of system identification methods to high-bandwidth rotorcraft flight control system design is examined. Flight test and modeling requirements are illustrated using flight test data from a BO-105 hingeless rotor helicopter. The proposed approach involves the identification of nonparametric (transfer function and state space) model identification. Results for the BO-105 show the need for including coupled body/rotor flapping and lead-lag dynamics in the identification model structure to allow the accurate prediction of control ssytem bandwidth limitations.

  18. Final Report on LDRD Project: High-Bandwidth Optical Data Interconnects for Satellite Applications

    SciTech Connect

    SERKLAND, DARWIN K.; GEIB, KENT M.; BLANSETT, ETHAN L.; KARPEN, GARY D.; PEAKE, GREGORY M.; HARGETT, TERRY; MONTANO, VICTORIA; SULLIVAN, CHARLES T.; ALLERMAN, ANDREW A.; RIENSTRA, JEFFREY L.

    2003-04-01

    This report describes the research accomplishments achieved under the LDRD Project ''High-Bandwidth Optical Data Interconnects for Satellite Applications.'' The goal of this LDRD has been to address the future needs of focal-plane-array (FPA) sensors by exploring the use of high-bandwidth fiber-optic interconnects to transmit FPA signals within a satellite. We have focused primarily on vertical-cavity surface-emitting laser (VCSEL) based transmitters, due to the previously demonstrated immunity of VCSELs to total radiation doses up to 1 Mrad. In addition, VCSELs offer high modulation bandwidth (roughly 10 GHz), low power consumption (roughly 5 mW), and high coupling efficiency (greater than -3dB) to optical fibers. In the first year of this LDRD, we concentrated on the task of transmitting analog signals from a cryogenic FPA to a remote analog-to-digital converter. In the second year, we considered the transmission of digital signals produced by the analog-to-digital converter to a remote computer on the satellite. Specifically, we considered the situation in which the FPA, analog-to-digital converter, and VCSEL-based transmitter were all cooled to cryogenic temperatures. This situation requires VCSELs that operate at cryogenic temperature, dissipate minimal heat, and meet the electrical drive requirements in terms of voltage, current, and bandwidth.

  19. High Bandwidth Rotary Fast Tool Servos and a Hybrid Rotary/Linear Electromagnetic Actuator

    SciTech Connect

    Montesanti, Richard Clement

    2005-09-01

    This thesis describes the development of two high bandwidth short-stroke rotary fast tool servos and the hybrid rotary/linear electromagnetic actuator developed for one of them. Design insights, trade-o® methodologies, and analytical tools are developed for precision mechanical systems, power and signal electronic systems, control systems, normal-stress electromagnetic actuators, and the dynamics of the combined systems.

  20. High-resolution and wide-bandwidth light intensity fiber optic displacement sensor for MEMS metrology.

    PubMed

    Orłowska, Karolina; Świątkowski, Michał; Kunicki, Piotr; Kopiec, Daniel; Gotszalk, Teodor

    2016-08-01

    We report on the design, properties, and applications of a high-resolution and wide-bandwidth light intensity fiber optic displacement sensor for microelectromechanical system (MEMS) metrology. There are two types of structures that the system is dedicated to: vibrating with both high and low frequencies. In order to ensure high-frequency and high-resolution measurements, frequency down mixing and selective signal processing were applied. The obtained effective measuring bandwidth ranges from single hertz to 1 megahertz. The achieved resolution presented here is 116  pm/Hz1/2 and 138  pm/Hz1/2 for low-frequency and high-frequency operation modes, respectively, whereas the measurement of static displacement is 100 μm.

  1. High-resolution and wide-bandwidth light intensity fiber optic displacement sensor for MEMS metrology.

    PubMed

    Orłowska, Karolina; Świątkowski, Michał; Kunicki, Piotr; Kopiec, Daniel; Gotszalk, Teodor

    2016-08-01

    We report on the design, properties, and applications of a high-resolution and wide-bandwidth light intensity fiber optic displacement sensor for microelectromechanical system (MEMS) metrology. There are two types of structures that the system is dedicated to: vibrating with both high and low frequencies. In order to ensure high-frequency and high-resolution measurements, frequency down mixing and selective signal processing were applied. The obtained effective measuring bandwidth ranges from single hertz to 1 megahertz. The achieved resolution presented here is 116  pm/Hz1/2 and 138  pm/Hz1/2 for low-frequency and high-frequency operation modes, respectively, whereas the measurement of static displacement is 100 μm. PMID:27505377

  2. Performance of a High-Concentration Erbium-Doped Fiber Amplifier with 100 nm Amplification Bandwidth

    SciTech Connect

    Hajireza, P.; Shahabuddin, N. S.; Abbasi-Zargaleh, S.; Emami, S. D.; Abdul-Rashid, H. A.; Yusoff, Z.

    2010-07-07

    Increasing demand for higher bandwidth has driven the need for higher Wavelength Division Multiplexing (WDM) channels. One of the requirements to achieve this is a broadband amplifier. This paper reports the performance of a broadband, compact, high-concentration and silica-based erbium-doped fiber amplifier. The amplifier optimized to a 2.15 m long erbium-doped fiber with erbium ion concentration of 2000 ppm. The gain spectrum of the amplifier has a measured amplification bandwidth of 100 nm using a 980 nm laser diode with power of 150 mW. This silica-based EDFA shows lower noise figure, higher gain and wider bandwidth in shorter wavelengths compared to Bismuth-based EDFA with higher erbium ion concentration of 3250 ppm at equivalent EDF length. The silica-based EDF shows peak gain at 22 dB and amplification bandwidth between 1520 nm and 1620 nm. The lowest noise figure is 5 dB. The gain is further improved with the implementation of enhanced EDFA configurations.

  3. High-bandwidth macro/microactuation for hard-disk drive

    NASA Astrophysics Data System (ADS)

    Ma, Jianxu; Ang, Marcelo H., Jr.

    2000-10-01

    The track density of hard disk drives had been increasing of 30%/year in these last years. The increase in bandwidth is limited by the presence of mechanical resonance modes and other nonlinear in the voice coil motor (VCM) actuators. One approach to overcoming the problem is by using a dual-stage servo mechanism. Dual stage actuator systems composed of a micro actuator and a conventional actuator (VCM)-macro actuator may enable such high track densities to be attained. In this paper, a novel piezoelectric microactuator was successfully designed and mounted on the suspension in hard disk drives. The microactuator is based on the deformation in piezoelectric effect, and drives the head suspension assembly. The paper describes the structure of macro/micro actuators, its principles of operation and mechanical characteristics. The actuators system in hard disk has a high bandwidth, simple structure, and low cost.

  4. Cavity resonance absorption in ultra-high bandwidth CRT deflection structure by a resistive load

    DOEpatents

    Dunham, Mark E.; Hudson, Charles L.

    1993-01-01

    An improved ultra-high bandwidth helical coil deflection structure for a hode ray tube is described comprising a first metal member having a bore therein, the metal walls of which form a first ground plane; a second metal member coaxially mounted in the bore of the first metal member and forming a second ground plane; a helical deflection coil coaxially mounted within the bore between the two ground planes; and a resistive load disposed in one end of the bore and electrically connected to the first and second ground planes, the resistive load having an impedance substantially equal to the characteristic impedance of the coaxial line formed by the two coaxial ground planes to inhibit cavity resonance in the structure within the ultra-high bandwidth of operation. Preferably, the resistive load comprises a carbon film on a surface of an end plug in one end of the bore.

  5. Cavity resonance absorption in ultra-high bandwidth CRT deflection structure by a resistive load

    DOEpatents

    Dunham, M.E.; Hudson, C.L.

    1993-05-11

    An improved ultra-high bandwidth helical coil deflection structure for a cathode ray tube is described comprising a first metal member having a bore therein, the metal walls of which form a first ground plane; a second metal member coaxially mounted in the bore of the first metal member and forming a second ground plane; a helical deflection coil coaxially mounted within the bore between the two ground planes; and a resistive load disposed in one end of the bore and electrically connected to the first and second ground planes, the resistive load having an impedance substantially equal to the characteristic impedance of the coaxial line formed by the two coaxial ground planes to inhibit cavity resonance in the structure within the ultra-high bandwidth of operation. Preferably, the resistive load comprises a carbon film on a surface of an end plug in one end of the bore.

  6. Techniques for High-Bandwidth (≥30 GHz) Chirped-Pulse Submillimeter-Wave Spectroscopy

    NASA Astrophysics Data System (ADS)

    Neill, Justin L.; Steber, Amanda L.; Harris, Brent J.; Pate, Brooks H.; Douglass, Kevin O.; Plusquellic, David F.; Gerecht, Eyal

    2011-06-01

    Due to the increased availability of active multiplier chains for converting microwave pulses into the millimeter/submillimeter with reasonably high power (≥1 mW), chirped pulses with high phase stability and complete arbitrary waveform generator (AWG) frequency agility can be created and employed for high-sensitivity molecular spectroscopy, as demonstrated at the Symposium in the past few years. The bandwidths of multiplier chains, however, can exceed the current limitations on digitizer bandwidth. Therefore, in order to obtain ≥30 GHz spectra in ~1 ms or less, techniques are being developed in which a two-channel AWG creates both the chirped pulses for molecular irradiation and a local oscillator pulse for heterodyne detection. These approaches reduce the digitizer bandwidths to 500 MHz or less to collect a high-bandwidth spectrum. A single instrument design can be used to measure both absorption and emission spectra, only requiring that the AWG pulses are changed. Due to the phase stability of the pulse generation and detection, coherent time-domain signal averaging can be performed to enhance sensitivity as desired. Preliminary results from prototype instruments designed at UVa and NIST will be presented, with sensitivity, frequency accuracy, and measurement speed comparisons to current millimeter/submillimeter-wave spectrometers. G.B. Park, A.H. Steeves, K. Kuyanov-Prozument, A.P. Colombo, R.W. Field, J.L. Neill, and B.H. Pate, RH07, 64th International Symposium on Molecular Spectroscopy (2009) K.O. Douglass, D.F. Plusquellic, and E. Gerecht, WH09, 65th International Symposium on Molecular Spectroscopy (2010).

  7. Automatic High-Bandwidth Calibration and Reconstruction of Arbitrarily Sampled Parallel MRI

    PubMed Central

    Aelterman, Jan; Naeyaert, Maarten; Gutierrez, Shandra; Luong, Hiep; Goossens, Bart; Pižurica, Aleksandra; Philips, Wilfried

    2014-01-01

    Today, many MRI reconstruction techniques exist for undersampled MRI data. Regularization-based techniques inspired by compressed sensing allow for the reconstruction of undersampled data that would lead to an ill-posed reconstruction problem. Parallel imaging enables the reconstruction of MRI images from undersampled multi-coil data that leads to a well-posed reconstruction problem. Autocalibrating pMRI techniques encompass pMRI techniques where no explicit knowledge of the coil sensivities is required. A first purpose of this paper is to derive a novel autocalibration approach for pMRI that allows for the estimation and use of smooth, but high-bandwidth coil profiles instead of a compactly supported kernel. These high-bandwidth models adhere more accurately to the physics of an antenna system. The second purpose of this paper is to demonstrate the feasibility of a parameter-free reconstruction algorithm that combines autocalibrating pMRI and compressed sensing. Therefore, we present several techniques for automatic parameter estimation in MRI reconstruction. Experiments show that a higher reconstruction accuracy can be had using high-bandwidth coil models and that the automatic parameter choices yield an acceptable result. PMID:24915203

  8. Mahanaxar: quality of service guarantees in high-bandwidth, real-time streaming data storage

    SciTech Connect

    Bigelow, David; Bent, John; Chen, Hsing-Bung; Brandt, Scott

    2010-04-05

    Large radio telescopes, cyber-security systems monitoring real-time network traffic, and others have specialized data storage needs: guaranteed capture of an ultra-high-bandwidth data stream, retention of the data long enough to determine what is 'interesting,' retention of interesting data indefinitely, and concurrent read/write access to determine what data is interesting, without interrupting the ongoing capture of incoming data. Mahanaxar addresses this problem. Mahanaxar guarantees streaming real-time data capture at (nearly) the full rate of the raw device, allows concurrent read and write access to the device on a best-effort basis without interrupting the data capture, and retains data as long as possible given the available storage. It has built in mechanisms for reliability and indexing, can scale to meet arbitrary bandwidth requirements, and handles both small and large data elements equally well. Results from our prototype implementation shows that Mahanaxar provides both better guarantees and better performance than traditional file systems.

  9. High-speed 405-nm superluminescent diode (SLD) with 807-MHz modulation bandwidth.

    PubMed

    Shen, Chao; Lee, Changmin; Ng, Tien Khee; Nakamura, Shuji; Speck, James S; DenBaars, Steven P; Alyamani, Ahmed Y; El-Desouki, Munir M; Ooi, Boon S

    2016-09-01

    III-nitride LEDs are fundamental components for visible-light communication (VLC). However, the modulation bandwidth is inherently limited by the relatively long carrier lifetime. In this letter, we present the 405 nm emitting superluminescent diode (SLD) with tilted facet design on semipolar GaN substrate, showing a broad emission of ~9 nm at 20 mW optical power. Owing to the fast recombination (τe<0.35 ns) through the amplified spontaneous emission, the SLD exhibits a significantly large 3-dB bandwidth of 807 MHz. A data rate of 1.3 Gbps with a bit-error rate of 2.9 × 10-3 was obtained using on-off keying modulation scheme, suggesting the SLD being a high-speed transmitter for VLC applications. PMID:27607634

  10. High-speed 850 nm VCSELs with 28 GHz modulation bandwidth for short reach communication

    NASA Astrophysics Data System (ADS)

    Westbergh, Petter; Safaisini, Rashid; Haglund, Erik; Gustavsson, Johan S.; Larsson, Anders; Joel, Andrew

    2013-03-01

    We present results from our new generation of high performance 850 nm oxide confined vertical cavity surface-emitting lasers (VCSELs). With devices optimized for high-speed operation under direct modulation, we achieve record high 3dB modulation bandwidths of 28 GHz for ~4 μm oxide aperture diameter VCSELs, and 27 GHz for devices with a ~7 μm oxide aperture diameter. Combined with a high-speed photoreceiver, the ~7 μm VCSEL enables error-free transmission at data rates up to 47 Gbit/s at room temperature, and up to 40 Gbit/s at 85°C.

  11. Highly Scaled InP/InGaAs DHBTs Beyond 1 THz Bandwidth

    NASA Astrophysics Data System (ADS)

    Rode, Johann Christian

    This work examines the efforts pursued to extend the bandwidth of InP-based DHBTs above 1 THz. Aggressive lithographic and epitaxial scaling of key device dimensions and simultaneous reduction of contact resistivities have enabled increased RF bandwidths by reduction of device RC and transit delays. A fabrication process for forming base electrodes and base/collector mesas of highly scaled transistors has been developed that exploits superior resolution (10nm) and alignment (<30nm) of electron beam lithography. Ultra-low resistance, thermally stable base contacts are critical for extended fmax bandwidth: a novel dual-deposition base metalization technique is presented that removes contaminating lithographic processes from the formation of the base contact, thereby enabling low resistivity contacts (4 Ω-microm2) to ultra-thin base layers (20 nm). The composite base metal stack exploits an ultra-thin layer of platinum that controllably reacts with base, yielding low contact resistivity, as well as a thick refractory diffusion barrier which permits stable operation at high current densities and elevated temperatures. Reduction in emitter-base surface leakage and subsequent increase of current gain was achieved by passivating emitter-base semiconductor surfaces with conformally grown ALD Al2O3. RF bandwidth limiting parasitics associated to the perimeter of highly scaled transistors have been identified and significantly reduced, among which are high sheet resistance of base electrodes, excess undercut of emitter stripes and improperly scaled base posts. At 100nm collector thickness, the breakdown voltage of the transistor BVCEO has been increased to more than 4.1V by passivating base/collector surfaces. With the technology improvements discussed, transistors with ftau of 480 GHz and fmax in excess of 1 THz have been demonstrated at 200nm emitter width and 80nm single-sided base contact width. Transistors at the same emitter width, but 30nm base contact width exhibit

  12. A Synthetic Bandwidth Method for High-Resolution SAR Based on PGA in the Range Dimension.

    PubMed

    Li, Jincheng; Chen, Jie; Liu, Wei; Wang, Pengbo; Li, Chunsheng

    2015-01-01

    The synthetic bandwidth technique is an effective method to achieve ultra-high range resolution in an SAR system. There are mainly two challenges in its implementation. The first one is the estimation and compensation of system errors, such as the timing deviation and the amplitude-phase error. Due to precision limitation of the radar instrument, construction of the sub-band signals becomes much more complicated with these errors. The second challenge lies in the combination method, that is how to fit the sub-band signals together into a much wider bandwidth. In this paper, a novel synthetic bandwidth approach is presented. It considers two main errors of the multi-sub-band SAR system and compensates them by a two-order PGA (phase gradient auto-focus)-based method, named TRPGA. Furthermore, an improved cut-paste method is proposed to combine the signals in the frequency domain. It exploits the redundancy of errors and requires only a limited amount of data in the azimuth direction for error estimation. Moreover, the up-sampling operation can be avoided in the combination process. Imaging results based on both simulated and real data are presented to validate the proposed approach.

  13. A Synthetic Bandwidth Method for High-Resolution SAR Based on PGA in the Range Dimension

    PubMed Central

    Li, Jincheng; Chen, Jie; Liu, Wei; Wang, Pengbo; Li, Chunsheng

    2015-01-01

    The synthetic bandwidth technique is an effective method to achieve ultra-high range resolution in an SAR system. There are mainly two challenges in its implementation. The first one is the estimation and compensation of system errors, such as the timing deviation and the amplitude-phase error. Due to precision limitation of the radar instrument, construction of the sub-band signals becomes much more complicated with these errors. The second challenge lies in the combination method, that is how to fit the sub-band signals together into a much wider bandwidth. In this paper, a novel synthetic bandwidth approach is presented. It considers two main errors of the multi-sub-band SAR system and compensates them by a two-order PGA (phase gradient auto-focus)-based method, named TRPGA. Furthermore, an improved cut-paste method is proposed to combine the signals in the frequency domain. It exploits the redundancy of errors and requires only a limited amount of data in the azimuth direction for error estimation. Moreover, the up-sampling operation can be avoided in the combination process. Imaging results based on both simulated and real data are presented to validate the proposed approach. PMID:26131679

  14. Narrow-bandwidth high-order harmonics driven by long-duration hot spots

    NASA Astrophysics Data System (ADS)

    Kozlov, Maxim; Kfir, Ofer; Fleischer, Avner; Kaplan, Alex; Carmon, Tal; Schwefel, Harald G. L.; Bartal, Guy; Cohen, Oren

    2012-06-01

    We predict and investigate the emission of high-order harmonics by atoms that cross intense laser hot spots that last for a nanosecond or longer. An atom that moves through a nanometer-scale hot spot at characteristic thermal velocity can emit high-order harmonics in a similar fashion to an atom that is irradiated by a short-duration (picosecond-scale) laser pulse. We analyze the collective emission from a thermal gas and from a jet of atoms. In both cases, the line shape of a high-order harmonic exhibits a narrow spike with spectral width that is determined by the bandwidth of the driving laser. Finally, we discuss a scheme for producing long-duration laser hot spots with intensity in the range of the intensity threshold for high-harmonic generation. In the proposed scheme, the hot spot is produced by a long laser pulse that is consecutively coupled to a high-quality micro-resonator and a metallic nano-antenna. This system may be used for generating ultra-narrow bandwidth extreme-ultraviolet radiation through frequency up-conversion of a low-cost compact pump laser.

  15. Demonstration of an X-Band Multilayer Yagi-Like Microstrip Patch Antenna With High Directivity and Large Bandwidth

    NASA Technical Reports Server (NTRS)

    Nessel, James A.; Zaman, Afroz; Lee, Richard Q.; Lambert, Kevin

    2005-01-01

    The feasibility of obtaining large bandwidth and high directivity from a multilayer Yagi-like microstrip patch antenna at 10 GHz is investigated. A measured 10-dB bandwidth of approximately 20 percent and directivity of approximately 11 dBi is demonstrated through the implementation of a vertically-stacked structure with three parasitic directors, above the driven patch, and a single reflector underneath the driven patch. Simulated and measured results are compared and show fairly close agreement. This antenna offers the advantages of large bandwidth, high directivity, and symmetrical broadside patterns, and could be applicable to satellite as well as terrestrial communications.

  16. High-bandwidth transfer of phase stability through a fiber frequency comb.

    PubMed

    Scharnhorst, Nils; Wübbena, Jannes B; Hannig, Stephan; Jakobsen, Kornelius; Kramer, Johannes; Leroux, Ian D; Schmidt, Piet O

    2015-07-27

    We demonstrate phase locking of a 729 nm diode laser to a 1542 nm master laser via an erbium-doped-fiber frequency comb, using a transfer-oscillator feedforward scheme which suppresses the effect of comb noise in an unprecedented 1.8 MHz bandwidth. We illustrate its performance by carrying out coherent manipulations of a trapped calcium ion with 99 % fidelity even at few-μs timescales. We thus demonstrate that transfer-oscillator locking can provide sufficient phase stability for high-fidelity quantum logic manipulation even without pre-stabilization of the slave diode laser. PMID:26367634

  17. Three-Axis Attitude Estimation With a High-Bandwidth Angular Rate Sensor

    NASA Technical Reports Server (NTRS)

    Bayard, David S.; Green, Joseph J.

    2013-01-01

    A continuing challenge for modern instrument pointing control systems is to meet the increasingly stringent pointing performance requirements imposed by emerging advanced scientific, defense, and civilian payloads. Instruments such as adaptive optics telescopes, space interferometers, and optical communications make unprecedented demands on precision pointing capabilities. A cost-effective method was developed for increasing the pointing performance for this class of NASA applications. The solution was to develop an attitude estimator that fuses star tracker and gyro measurements with a high-bandwidth angular rotation sensor (ARS). An ARS is a rate sensor whose bandwidth extends well beyond that of the gyro, typically up to 1,000 Hz or higher. The most promising ARS sensor technology is based on a magnetohydrodynamic concept, and has recently become available commercially. The key idea is that the sensor fusion of the star tracker, gyro, and ARS provides a high-bandwidth attitude estimate suitable for supporting pointing control with a fast-steering mirror or other type of tip/tilt correction for increased performance. The ARS is relatively inexpensive and can be bolted directly next to the gyro and star tracker on the spacecraft bus. The high-bandwidth attitude estimator fuses an ARS sensor with a standard three-axis suite comprised of a gyro and star tracker. The estimation architecture is based on a dual-complementary filter (DCF) structure. The DCF takes a frequency- weighted combination of the sensors such that each sensor is most heavily weighted in a frequency region where it has the lowest noise. An important property of the DCF is that it avoids the need to model disturbance torques in the filter mechanization. This is important because the disturbance torques are generally not known in applications. This property represents an advantage over the prior art because it overcomes a weakness of the Kalman filter that arises when fusing more than one rate

  18. Engineering the CernVM-Filesystem as a High Bandwidth Distributed Filesystem for Auxiliary Physics Data

    SciTech Connect

    Dykstra, D.; Bockelman, B.; Blomer, J.; Herner, K.; Levshina, T.; Slyz, M.

    2015-12-23

    A common use pattern in the computing models of particle physics experiments is running many distributed applications that read from a shared set of data files. We refer to this data is auxiliary data, to distinguish it from (a) event data from the detector (which tends to be different for every job), and (b) conditions data about the detector (which tends to be the same for each job in a batch of jobs). Relatively speaking, conditions data also tends to be relatively small per job where both event data and auxiliary data are larger per job. Unlike event data, auxiliary data comes from a limited working set of shared files. Since there is spatial locality of the auxiliary data access, the use case appears to be identical to that of the CernVM- Filesystem (CVMFS). However, we show that distributing auxiliary data through CVMFS causes the existing CVMFS infrastructure to perform poorly. We utilize a CVMFS client feature called 'alien cache' to cache data on existing local high-bandwidth data servers that were engineered for storing event data. This cache is shared between the worker nodes at a site and replaces caching CVMFS files on both the worker node local disks and on the site's local squids. We have tested this alien cache with the dCache NFSv4.1 interface, Lustre, and the Hadoop Distributed File System (HDFS) FUSE interface, and measured performance. In addition, we use high-bandwidth data servers at central sites to perform the CVMFS Stratum 1 function instead of the low-bandwidth web servers deployed for the CVMFS software distribution function. We have tested this using the dCache HTTP interface. As a result, we have a design for an end-to-end high-bandwidth distributed caching read-only filesystem, using existing client software already widely deployed to grid worker nodes and existing file servers already widely installed at grid sites. Files are published in a central place and are soon available on demand throughout the grid and cached locally on the

  19. Engineering the CernVM-Filesystem as a High Bandwidth Distributed Filesystem for Auxiliary Physics Data

    NASA Astrophysics Data System (ADS)

    Dykstra, D.; Bockelman, B.; Blomer, J.; Herner, K.; Levshina, T.; Slyz, M.

    2015-12-01

    A common use pattern in the computing models of particle physics experiments is running many distributed applications that read from a shared set of data files. We refer to this data is auxiliary data, to distinguish it from (a) event data from the detector (which tends to be different for every job), and (b) conditions data about the detector (which tends to be the same for each job in a batch of jobs). Relatively speaking, conditions data also tends to be relatively small per job where both event data and auxiliary data are larger per job. Unlike event data, auxiliary data comes from a limited working set of shared files. Since there is spatial locality of the auxiliary data access, the use case appears to be identical to that of the CernVM- Filesystem (CVMFS). However, we show that distributing auxiliary data through CVMFS causes the existing CVMFS infrastructure to perform poorly. We utilize a CVMFS client feature called "alien cache" to cache data on existing local high-bandwidth data servers that were engineered for storing event data. This cache is shared between the worker nodes at a site and replaces caching CVMFS files on both the worker node local disks and on the site's local squids. We have tested this alien cache with the dCache NFSv4.1 interface, Lustre, and the Hadoop Distributed File System (HDFS) FUSE interface, and measured performance. In addition, we use high-bandwidth data servers at central sites to perform the CVMFS Stratum 1 function instead of the low-bandwidth web servers deployed for the CVMFS software distribution function. We have tested this using the dCache HTTP interface. As a result, we have a design for an end-to-end high-bandwidth distributed caching read-only filesystem, using existing client software already widely deployed to grid worker nodes and existing file servers already widely installed at grid sites. Files are published in a central place and are soon available on demand throughout the grid and cached locally on the

  20. Extended high-frequency bandwidth improves reception of speech in spatially separated masking speech

    PubMed Central

    Levy, Suzanne Carr; Freed, Daniel J.; Nilsson, Michael; Moore, Brian C.J.; Puria, Sunil

    2015-01-01

    increased from 4 to 10 kHz was 1.3 dB for the asymmetric condition and 0.5 dB for the diffuse condition. Conclusions Extending bandwidth from 4 to 10 kHz can improve the ability of normal-hearing and hearing-impaired participants to understand target speech in the presence of spatially separated masking speech. Future studies of the benefits of extended high-frequency amplification should investigate other realistic listening situations, masker types, spatial configurations, and room reverberation conditions, to determine added value in overcoming the technical challenges associated with implementing a device capable of providing extended high-frequency amplification. PMID:25856543

  1. High Current Responsivity and Wide Modulation Bandwidth Terahertz Detector Using High-Electron-Mobility Transistor for Wireless Communication

    NASA Astrophysics Data System (ADS)

    Suzuki, S.; Nukariya, T.; Ueda, Y.; Otsuka, T.; Asada, M.

    2016-07-01

    A high-current-responsivity terahertz (THz) detector was fabricated using a broadband bow-tie antenna and an InAlAs/InGaAs high-electron-mobility transistor (HEMT) with a short gate length. High-current responsivity can be achieved by using a short gate length; the resulting high transconductance exhibited ballistic transport in the channel. We fabricated the HEMT detector with a 50-nm-long channel; the transconductance was 1.2 S/mm and the subthreshold slope was 120 mV/dec, yielding a high-current responsivity (˜5 A/W) and a cutoff frequency of 460 GHz. We also measured the modulation bandwidth of the THz detector using a heterodyne mixing technique with a uni-traveling carrier photodiode (UTC-PD) for providing the radio frequency (RF) and a frequency multiplier as a local oscillator. The intensity of the intermediate signal (IF) was measured by changing the frequency of the UTC-PD; very high bandwidths of up to 26 GHz were obtained. The experimental results agree well with electromagnetic simulations, which indicate that the bandwidth is determined by the external circuit. The conversion gain from RF to IF was -2 dB in the heterodyne mixing by using the HEMT detector.

  2. High time-bandwidth product and high repetition rate period signal generation based on spectral hole burning crystal.

    PubMed

    Ma, Xiurong; Wang, Song; Liang, Yuqing; Shan, Yunlong

    2015-04-01

    This paper proposes an approach for the generation of high time-bandwidth product (TBP) and high repetition rate pulse compression period signal. The complex spectral grating is created through a reference pulse and multiple programming pulses with different start frequencies. As the multiple probe chirped pulses with different start frequencies interact with the complex spectral gratings, a high TBP and repetition rate period signal is thus generated. This technique has the potential to generate a time-bandwidth product of 10⁵ when the repetition rate reaches up to tens of GHz. At the end of this paper, two simulation results of pulse compression period signal with 4×10⁵ TBP and 20 GHz repetition rate are presented.

  3. The fusion diagnostic gamma experiment: A high-bandwidth fusion diagnostic of the National Ignition Facility

    SciTech Connect

    Moran, M.J.

    1999-01-01

    Diagnostics for the National Ignition Facility/inertial confinement fusion program must include good characterization of the fusion source. Ideally, diagnostics would measure the spatially resolved history of the fusion reaction rate and temperature. Existing diagnostics can satisfy this goal only partially. One class of new techniques that could play a major role in high-yield diagnostics is measurements based on fusion {gamma} rays. The fusion diagnostic gamma experiment can perform energy-resolved measurements of (D,T) fusion reaction rates. This diagnostic is based on the 16.7 MeV {gamma} rays that are produced by (D,T) fusion. The {gamma} rays are free of spectral dispersion and can be detected (via Compton recoil electrons) with a high bandwidth Cherenkov detector. A simple magnetic monochromator selects signals from the 16.7 MeV {gamma} rays and reduces background signals from nonfusion {gamma} rays. {copyright} {ital 1998 American Institute of Physics.}

  4. Applied techniques for high bandwidth data transfers across wide area networks

    SciTech Connect

    Lee, Jason; Gunter, Dan; Tierney, Brian; Allcock, Bill; Bester, Joe; Bresnahan, John; Tuecke, Steve

    2001-04-30

    Large distributed systems such as Computational/Data Grids require large amounts of data to be co-located with the computing facilities for processing. Ensuring that the data is there in time for the computation in today's Internet is a massive problem. From our work developing a scalable distributed network cache, we have gained experience with techniques necessary to achieve high data throughput over high bandwidth Wide Area Networks (WAN). In this paper, we discuss several hardware and software design techniques and issues, and then describe their application to an implementation of an enhanced FTP protocol called GridFTP. We also describe results from two applications using these techniques, which were obtained at the Supercomputing 2000 conference.

  5. A Study of an Optical Lunar Surface Communications Network with High Bandwidth Direct to Earth Link

    NASA Technical Reports Server (NTRS)

    Wilson, K.; Biswas, A.; Schoolcraft, J.

    2011-01-01

    A lunar surface systems study explores the application of optical communications to support a high bandwidth data link from a lunar relay satellite and from fixed lunar assets. The results show that existing 1-m ground stations could provide more than 99% coverage of the lunar terminal at 100Mb/s data rates from a lunar relay satellite and in excess of 200Mb/s from a fixed terminal on the lunar surface. We have looked at the effects of the lunar regolith and its removal on optical samples. Our results indicate that under repeated dust removal episodes sapphire rather than fused silica would be a more durable material for optical surfaces. Disruption tolerant network protocols can minimize the data loss due to link dropouts. We report on the preliminary results of the DTN protocol implemented over the optical carrier.

  6. Tri-material multilayer coatings with high reflectivity and wide bandwidth for 25 to 50 nm extreme ultraviolet light.

    PubMed

    Aquila, A; Salmassi, F; Liu, Yanwei; Gullikson, E M

    2009-11-23

    Magnesium/silicon carbide (Mg/SiC) multilayers have been fabricated with normal incidence reflectivity in the vicinity of 40% to 50% for wavelengths in the 25 to 50 nm wavelength range. However many applications, for example solar telescopes and ultrafast studies using high harmonic generation sources, desire larger bandwidths than provided by high reflectivity Mg/SiC multilayers. We investigate introducing a third material, Scandium, to create a tri-material Mg/Sc/SiC multilayer allowing an increase the bandwidth while maintaining high reflectivity. PMID:19997456

  7. Tri-material multilayer coatings with high reflectivity and wide bandwidth for 25 to 50 nm extreme ultraviolet light

    SciTech Connect

    Aquila, Andrew; Salmassi, Farhad; Liu, Yanwei; Gullikson, Eric M.

    2009-09-09

    Magnesium/silicon carbide (Mg/SiC) multilayers have been fabricated with normal incidence reflectivity in the vicinity of 40% to 50% for wavelengths in the 25 to 50 nm wavelength range. However many applications, for example solar telescopes and ultrafast studies using high harmonic generation sources, desire larger bandwidths than provided by high reflectivity Mg/SiC multilayers. We investigate introducing a third material, Scandium, to create a tri-material Mg/Sc/SiC multilayer allowing an increase the bandwidth while maintaining high reflectivity.

  8. Beyond Bandwidth. . .

    ERIC Educational Resources Information Center

    Bruce, James D.

    2003-01-01

    Explores the implications and possibilities for colleges and universities as higher education goes "beyond bandwidth"--beyond the computing speed, innovative applications, and technological capabilities deployed globally today. (EV)

  9. Radiation-tolerant, low-mass, high bandwidth, flexible printed circuit cables for particle physics experiments

    NASA Astrophysics Data System (ADS)

    McFadden, N. C.; Hoeferkamp, M. R.; Seidel, S.

    2016-09-01

    The design of meter long flexible printed circuit cables required for low-mass ultra-high speed signal transmission in the high radiation environment of the High Luminosity Large Hadron Collider is described. The design geometry is a differential embedded microstrip with 100 Ω nominal impedance. Minimal mass and maximal radiation hardness are pre-eminent considerations. Several dielectric materials are compared. To reduce mass, a cross hatched ground plane is applied. The long flexible printed circuit cables are characterized in bit error rate tests, attenuation versus frequency, mechanical response to temperature induced stress, and dimensional implications on radiation length. These tests are performed before and after irradiation with 1 MeV neutrons to 2×1016/cm2 and 800 MeV protons to 2×1016 1-MeV neutron equivalent/cm2. A 1.0 m Kapton cable with cross hatched ground plane, effective bandwidth of 4.976 gigabits per second, 0.0160% of a radiation length, and no detectable radiation-induced mechanical or electrical degradation is obtained.

  10. Gbps wireless transceivers for high bandwidth interconnections in distributed cyber physical systems

    NASA Astrophysics Data System (ADS)

    Saponara, Sergio; Neri, Bruno

    2015-05-01

    In Cyber Physical Systems there is a growing use of high speed sensors like photo and video camera, radio and light detection and ranging (Radar/Lidar) sensors. Hence Cyber Physical Systems can benefit from the high communication data rate, several Gbps, that can be provided by mm-wave wireless transceivers. At such high frequency the wavelength is few mm and hence the whole transceiver including the antenna can be integrated in a single chip. To this aim this paper presents the design of 60 GHz transceiver architecture to ensure connection distances up to 10 m and data rate up to 4 Gbps. At 60 GHz there are more than 7 GHz of unlicensed bandwidth (available for free for development of new services). By using a CMOS SOI technology RF, analog and digital baseband circuitry can be integrated in the same chip minimizing noise coupling. Even the antenna is integrated on chip reducing cost and size vs. classic off-chip antenna solutions. Therefore the proposed transceiver can enable at physical layer the implementation of low cost nodes for a Cyber Physical System with data rates of several Gbps and with a communication distance suitable for home/office scenarios, or on-board vehicles such as cars, trains, ships, airplanes

  11. High power fiber MOPA based QCW laser delivering pulses with arbitrary duration on demand at high modulation bandwidth.

    PubMed

    Petkovšek, Rok; Novak, Vid; Agrež, Vid

    2015-12-28

    We report on a concept of a fiber MOPA based quasi-CW laser working at high modulation bandwidths up to 40 MHz capable of producing arbitrary pulse durations at arbitrary repetition rates. An output power of over 100 W was achieved and an on-off contrast of 25 dB. The laser features a dual-channel (dual-wavelength) seed source, a double stage YDF amplifier and a volume-Bragg-grating-based signal de-multiplexer. Minimization of transients was conducted through experiment and model analysis. PMID:26831982

  12. Narrow-Bandwidth Tunable Infrared Difference-Frequency Generation at High Repetition Rates in LilO(3).

    PubMed

    Goldberg, L S

    1975-03-01

    Difference-frequency generation was studied in LiIO(3) with a narrow-bandwidth tunable dye laser pumped at high pulse-repetition rates by a frequency-doubled Nd:YAG laser. Tunable infrared radiation of 0.1, cm(-1) bandwidth was generated from 1.25 mum to 1.60 mum and from 3.40 mum to 5.65 mum by mixing rhodamine B dye laser cavity radiation with the 1.064-mum or 532-nm output of the Nd:YAG laser.

  13. Design, analysis and testing of a parallel-kinematic high-bandwidth XY nanopositioning stage

    SciTech Connect

    Li, Chun-Xia; Gu, Guo-Ying; Yang, Mei-Ju; Zhu, Li-Min

    2013-12-15

    This paper presents the design, analysis, and testing of a parallel-kinematic high-bandwidth XY nanopositioning stage driven by piezoelectric stack actuators. The stage is designed with two kinematic chains. In each kinematic chain, the end-effector of the stage is connected to the base by two symmetrically distributed flexure modules, respectively. Each flexure module comprises a fixed-fixed beam and a parallelogram flexure serving as two orthogonal prismatic joints. With the purpose to achieve high resonance frequencies of the stage, a novel center-thickened beam which has large stiffness is proposed to act as the fixed-fixed beam. The center-thickened beam also contributes to reducing cross-coupling and restricting parasitic motion. To decouple the motion in two axes totally, a symmetric configuration is adopted for the parallelogram flexures. Based on the analytical models established in static and dynamic analysis, the dimensions of the stage are optimized in order to maximize the first resonance frequency. Then finite element analysis is utilized to validate the design and a prototype of the stage is fabricated for performance tests. According to the results of static and dynamic tests, the resonance frequencies of the developed stage are over 13.6 kHz and the workspace is 11.2 μm × 11.6 μm with the cross-coupling between two axes less than 0.52%. It is clearly demonstrated that the developed stage has high resonance frequencies, a relatively large travel range, and nearly decoupled performance between two axes. For high-speed tracking performance tests, an inversion-based feedforward controller is implemented for the stage to compensate for the positioning errors caused by mechanical vibration. The experimental results show that good tracking performance at high speed is achieved, which validates the effectiveness of the developed stage.

  14. High-order random Raman lasing in a PM fiber with ultimate efficiency and narrow bandwidth.

    PubMed

    Babin, Sergey A; Zlobina, Ekaterina A; Kablukov, Sergey I; Podivilov, Evgeniy V

    2016-01-01

    Random Raman lasers attract now a great deal of attention as they operate in non-active turbid or transparent scattering media. In the last case, single mode fibers with feedback via Rayleigh backscattering generate a high-quality unidirectional laser beam. However, such fiber lasers have rather poor spectral and polarization properties, worsening with increasing power and Stokes order. Here we demonstrate a linearly-polarized cascaded random Raman lasing in a polarization-maintaining fiber. The quantum efficiency of converting the pump (1.05 μm) into the output radiation is almost independent of the Stokes order, amounting to 79%, 83%, and 77% for the 1(st) (1.11 μm), 2(nd) (1.17 μm) and 3(rd) (1.23 μm) order, respectively, at the polarization extinction ratio >22 dB for all orders. The laser bandwidth grows with increasing order, but it is almost independent of power in the 1-10 W range, amounting to ~1, ~2 and ~3 nm for orders 1-3, respectively. So, the random Raman laser exhibits no degradation of output characteristics with increasing Stokes order. A theory adequately describing the unique laser features has been developed. Thus, a full picture of the cascaded random Raman lasing in fibers is shown. PMID:26940082

  15. Method and apparatus for providing high bandwidth, low noise mechanical I/O for computer systems

    DOEpatents

    Rosenberg, Louis B.

    1998-01-01

    A method and apparatus for providing high bandwidth and low noise mechanical input and output for computer systems. A gimbal mechanism provides two revolute degrees of freedom to an object about two axes of rotation. A linear axis member is coupled to the gimbal mechanism at the intersection of the two axes of rotation. The linear axis member is capable of being translated along a third axis to provide a third degree of freedom. The user object is coupled to the linear axis member and is thus translatable along the third axis so that the object can be moved along all three degrees of freedom. Transducers associated with the provided degrees of freedom include sensors and actuators and provide an electromechanical interface between the object and a digital processing system. Capstan drive mechanisms transmit forces between the transducers and the object. The linear axis member can also be rotated about its lengthwise axis to provide a fourth degree of freedom, and, optionally, a floating gimbal mechanism is coupled to the linear axis member to provide fifth and sixth degrees of freedom to an object. Transducer sensors are associated with the fourth, fifth, and sixth degrees of freedom. The interface is well suited for simulations of medical procedures and simulations in which an object such as a stylus or a joystick is moved and manipulated by the user.

  16. Low latency, high bandwidth data communications between compute nodes in a parallel computer

    DOEpatents

    Archer, Charles J.; Blocksome, Michael A.; Ratterman, Joseph D.; Smith, Brian E.

    2010-11-02

    Methods, parallel computers, and computer program products are disclosed for low latency, high bandwidth data communications between compute nodes in a parallel computer. Embodiments include receiving, by an origin direct memory access (`DMA`) engine of an origin compute node, data for transfer to a target compute node; sending, by the origin DMA engine of the origin compute node to a target DMA engine on the target compute node, a request to send (`RTS`) message; transferring, by the origin DMA engine, a predetermined portion of the data to the target compute node using memory FIFO operation; determining, by the origin DMA engine whether an acknowledgement of the RTS message has been received from the target DMA engine; if the an acknowledgement of the RTS message has not been received, transferring, by the origin DMA engine, another predetermined portion of the data to the target compute node using a memory FIFO operation; and if the acknowledgement of the RTS message has been received by the origin DMA engine, transferring, by the origin DMA engine, any remaining portion of the data to the target compute node using a direct put operation.

  17. Digital modulation schemes for high speed transmission through low bandwidth lowpass analog links

    NASA Technical Reports Server (NTRS)

    Andrawis, Alfred S.; Flippin, Quentin J.

    1995-01-01

    Existing NTSC (National Television System Committee) standard will be phased out and replaced with HDTV (High Definition Television) standard within the next 10 years. Accordingly, the existing video network system operated by NASA will become obsolete and requires either replacement or modification to accommodate digital transmission. Network replacement is extremely expensive, hence, several digital modulation schemes are investigated in this report to accomplish digital transmission over existing analog links saving NASA from the cost of network replacement. There are two competing transmission systems available for HDTV transmission over limited bandwidth channels. The cost and performance of the two competing schemes are remarkably similar. However, the input data rate in such a case is limited to 40 Mbit/s. Transmission of higher data rates is possible using simple signal processing techniques. On the other hand, a third transmission system, multilevel pulse amplitude modulation (M-PAM) is proposed. M-PAM is the first stage of the well known M-VSB. This M-PAM scheme is much simpler and uses the channel more efficiently. The three schemes are compared and preliminary conclusions were made. Despite of several similarities, each modulation scheme has it unique merits. To determine the suitability of each scheme, more investigations and laboratory tests for all schemes are needed.

  18. Wide bandwidth optical signals for high range resolution measurements in water

    NASA Astrophysics Data System (ADS)

    Nash, Justin; Lee, Robert; Mullen, Linda

    2016-05-01

    Measurements with high range resolution are needed to identify underwater threats, especially when two-dimensional contrast information is insufficient to extract object details. The challenge is that optical measurements are limited by scattering phenomena induced by the underwater channel. Back-scatter results in transmitted photons being directed back to the receiver before reaching the target of interest which induces a clutter signal for ranging and a reduction in contrast for imaging. Multiple small-angle scattering (forward-scatter) results in transmitted photons being directed to unintended regions of the target of interest (spatial spreading), while also stretching the temporal profile of a short optical pulse (temporal spreading). Spatial and temporal spreading of the optical signal combine to cause a reduction in range resolution in conventional laser imaging systems. NAVAIR has investigated ways in which wide bandwidth, modulated optical signals can be utilized to improve ranging and imaging performance in turbid water environments. Experimental efforts have been conducted to investigate channel effects on the propagated frequency content, as well as different filtering and processing techniques on the return signals to maximize range resolution. Of particular interest for the modulated pulses are coherent detection and processing techniques employed by the radar community, including methods to reduce sidelobe clutter. This paper will summarize NAVAIR's work and show that wideband optical signals, in combination with the CLEAN algorithm, can indeed provide enhancements to range resolution and 3D imagery in turbid water environments.

  19. Controllable high bandwidth storage of optical information in a Bose-Einstein Condensate

    NASA Astrophysics Data System (ADS)

    Jayaseelan, Maitreyi; Schultz, Justin T.; Murphree, Joseph D.; Hansen, Azure; Bigelow, Nicholas P.

    2016-05-01

    The storage and retrieval of optical information has been of interest for a variety of applications including quantum information processing, quantum networks and quantum memories. Several schemes have been investigated and realized with weak, narrowband pulses, including techniques using EIT in solid state systems and both hot and cold atomic vapors. In contrast, we investigate the storage and manipulation of strong, high bandwidth pulses in a Bose-Einstein Condensate (BEC) of ultracold 87 Rb atoms. As a storage medium for optical pulses, BECs offer long storage times and preserve the coherence properties of the input information, suppressing unwanted thermal decoherence effects. We present numerical simulations of nanosecond pulses addressing a three-level lambda system on the D2 line of 87 Rb. The signal pulse is stored as a localized spin excitation in the condensate and can be moved or retrieved by reapplication of successive control pulses. The relative Rabi frequencies and areas of the pulses and the local atomic density in the condensate determine the storage location and readout of the signal pulse. Extending this scheme to use beams with a variety of spatial modes such as Hermite- and Laguerre-Gaussian modes offers an expanded alphabet for information storage.

  20. High-order random Raman lasing in a PM fiber with ultimate efficiency and narrow bandwidth

    PubMed Central

    Babin, Sergey A.; Zlobina, Ekaterina A.; Kablukov, Sergey I.; Podivilov, Evgeniy V.

    2016-01-01

    Random Raman lasers attract now a great deal of attention as they operate in non-active turbid or transparent scattering media. In the last case, single mode fibers with feedback via Rayleigh backscattering generate a high-quality unidirectional laser beam. However, such fiber lasers have rather poor spectral and polarization properties, worsening with increasing power and Stokes order. Here we demonstrate a linearly-polarized cascaded random Raman lasing in a polarization-maintaining fiber. The quantum efficiency of converting the pump (1.05 μm) into the output radiation is almost independent of the Stokes order, amounting to 79%, 83%, and 77% for the 1st (1.11 μm), 2nd (1.17 μm) and 3rd (1.23 μm) order, respectively, at the polarization extinction ratio >22 dB for all orders. The laser bandwidth grows with increasing order, but it is almost independent of power in the 1–10 W range, amounting to ~1, ~2 and ~3 nm for orders 1–3, respectively. So, the random Raman laser exhibits no degradation of output characteristics with increasing Stokes order. A theory adequately describing the unique laser features has been developed. Thus, a full picture of the cascaded random Raman lasing in fibers is shown. PMID:26940082

  1. Analysis of laser damage tests on a coating for broad bandwidth high reflection of femtosecond pulses

    NASA Astrophysics Data System (ADS)

    Bellum, John; Winstone, Trevor; Lamaignere, Laurent; Sozet, Martin; Kimmel, Mark; Rambo, Patrick; Field, Ella; Kletecka, Damon

    2015-07-01

    We have designed and produced an optical coating suitable for broad bandwidth high reflection (BBHR) at 45° angle of incidence (AOI), P polarization (Ppol) of petawatt (PW) class fs laser pulses of ~ 900 nm center wavelength. We have produced such BBHR coatings consisting of TiO2/SiO2 layer pairs deposited by ion assisted e-beam evaporation using the large optics coater at Sandia National Laboratories. This paper focuses on laser-induced damage threshold (LIDT) tests of these coatings. LIDT is difficult to measure for such coatings due to the broad range of wavelengths over which they can operate. An ideal test would be in the vacuum environment of the fs-pulse PW use laser using fs pulses identical to of the PW laser. Short of this ideal testing would be tests over portions of the HR band of the BBHR coating using ns or sub-ps pulses produced by tunable lasers. Such tests could be over ~ 10 nm wide wavelength intervals whose center wavelengths could be tuned over the BBHR coating's operational band. Alternatively, the HR band of the BBHR coating could be adjusted by means of wavelength shifts due to changing the AOI of the LIDT tests or due to absorbed moisture by the coating under ambient conditions. We conduct LIDT tests on the BBHR coatings at selected AOIs to gain insight into the coatings' laser damage properties, and analyze how the results of the different LIDT tests compare.

  2. Effects of bandwidth, compression speed, and gain at high frequencies on preferences for amplified music.

    PubMed

    Moore, Brian C J

    2012-09-01

    This article reviews a series of studies on the factors influencing sound quality preferences, mostly for jazz and classical music stimuli. The data were obtained using ratings of individual stimuli or using the method of paired comparisons. For normal-hearing participants, the highest ratings of sound quality were obtained when the reproduction bandwidth was wide (55 to 16000 Hz) and ripples in the frequency response were small (less than ± 5 dB). For hearing-impaired participants listening via a simulated five-channel compression hearing aid with gains set using the CAM2 fitting method, preferences for upper cutoff frequency varied across participants: Some preferred a 7.5- or 10-kHz upper cutoff frequency over a 5-kHz cutoff frequency, and some showed the opposite preference. Preferences for a higher upper cutoff frequency were associated with a shallow high-frequency slope of the audiogram. A subsequent study comparing the CAM2 and NAL-NL2 fitting methods, with gains slightly reduced for participants who were not experienced hearing aid users, showed a consistent preference for CAM2. Since the two methods differ mainly in the gain applied for frequencies above 4 kHz (CAM2 recommending higher gain than NAL-NL2), these results suggest that extending the upper cutoff frequency is beneficial. A system for reducing "overshoot" effects produced by compression gave small but significant benefits for sound quality of a percussion instrument (xylophone). For a high-input level (80 dB SPL), slow compression was preferred over fast compression. PMID:23172008

  3. Effects of Bandwidth, Compression Speed, and Gain at High Frequencies on Preferences for Amplified Music

    PubMed Central

    2012-01-01

    This article reviews a series of studies on the factors influencing sound quality preferences, mostly for jazz and classical music stimuli. The data were obtained using ratings of individual stimuli or using the method of paired comparisons. For normal-hearing participants, the highest ratings of sound quality were obtained when the reproduction bandwidth was wide (55 to 16000 Hz) and ripples in the frequency response were small (less than ± 5 dB). For hearing-impaired participants listening via a simulated five-channel compression hearing aid with gains set using the CAM2 fitting method, preferences for upper cutoff frequency varied across participants: Some preferred a 7.5- or 10-kHz upper cutoff frequency over a 5-kHz cutoff frequency, and some showed the opposite preference. Preferences for a higher upper cutoff frequency were associated with a shallow high-frequency slope of the audiogram. A subsequent study comparing the CAM2 and NAL-NL2 fitting methods, with gains slightly reduced for participants who were not experienced hearing aid users, showed a consistent preference for CAM2. Since the two methods differ mainly in the gain applied for frequencies above 4 kHz (CAM2 recommending higher gain than NAL-NL2), these results suggest that extending the upper cutoff frequency is beneficial. A system for reducing “overshoot” effects produced by compression gave small but significant benefits for sound quality of a percussion instrument (xylophone). For a high-input level (80 dB SPL), slow compression was preferred over fast compression. PMID:23172008

  4. Performance Evaluation of a High Bandwidth Liquid Fuel Modulation Valve for Active Combustion Control

    NASA Technical Reports Server (NTRS)

    Saus, Joseph R.; DeLaat, John C.; Chang, Clarence T.; Vrnak, Daniel R.

    2012-01-01

    At the NASA Glenn Research Center, a characterization rig was designed and constructed for the purpose of evaluating high bandwidth liquid fuel modulation devices to determine their suitability for active combustion control research. Incorporated into the rig s design are features that approximate conditions similar to those that would be encountered by a candidate device if it were installed on an actual combustion research rig. The characterized dynamic performance measures obtained through testing in the rig are planned to be accurate indicators of expected performance in an actual combustion testing environment. To evaluate how well the characterization rig predicts fuel modulator dynamic performance, characterization rig data was compared with performance data for a fuel modulator candidate when the candidate was in operation during combustion testing. Specifically, the nominal and off-nominal performance data for a magnetostrictive-actuated proportional fuel modulation valve is described. Valve performance data were collected with the characterization rig configured to emulate two different combustion rig fuel feed systems. Fuel mass flows and pressures, fuel feed line lengths, and fuel injector orifice size was approximated in the characterization rig. Valve performance data were also collected with the valve modulating the fuel into the two combustor rigs. Comparison of the predicted and actual valve performance data show that when the valve is operated near its design condition the characterization rig can appropriately predict the installed performance of the valve. Improvements to the characterization rig and accompanying modeling activities are underway to more accurately predict performance, especially for the devices under development to modulate fuel into the much smaller fuel injectors anticipated in future lean-burning low-emissions aircraft engine combustors.

  5. A high performance long-reach passive optical network with a novel excess bandwidth distribution scheme

    NASA Astrophysics Data System (ADS)

    Chao, I.-Fen; Zhang, Tsung-Min

    2015-06-01

    Long-reach passive optical networks (LR-PONs) have been considered to be promising solutions for future access networks. In this paper, we propose a distributed medium access control (MAC) scheme over an advantageous LR-PON network architecture that reroutes the control information from and back to all ONUs through an (N + 1) × (N + 1) star coupler (SC) deployed near the ONUs, thereby overwhelming the extremely long propagation delay problem in LR-PONs. In the network, the control slot is designed to contain all bandwidth requirements of all ONUs and is in-band time-division-multiplexed with a number of data slots within a cycle. In the proposed MAC scheme, a novel profit-weight-based dynamic bandwidth allocation (P-DBA) scheme is presented. The algorithm is designed to efficiently and fairly distribute the amount of excess bandwidth based on a profit value derived from the excess bandwidth usage of each ONU, which resolves the problems of previously reported DBA schemes that are either unfair or inefficient. The simulation results show that the proposed decentralized algorithms exhibit a nearly three-order-of-magnitude improvement in delay performance compared to the centralized algorithms over LR-PONs. Moreover, the newly proposed P-DBA scheme guarantees low delay performance and fairness even when under attack by the malevolent ONU irrespective of traffic loads and burstiness.

  6. Theoretical investigation of injection-locked high modulation bandwidth quantum cascade lasers.

    PubMed

    Meng, Bo; Wang, Qi Jie

    2012-01-16

    In this study, we report for the first time to our knowledge theoretical investigation of modulation responses of injection-locked mid-infrared quantum cascade lasers (QCLs) at wavelengths of 4.6 μm and 9 μm, respectively. It is shown through a three-level rate equations model that the direct intensity modulation of QCLs gives the maximum modulation bandwidths of ~7 GHz at 4.6 μm and ~20 GHz at 9 μm. By applying the injection locking scheme, we find that the modulation bandwidths of up to ~30 GHz and ~70 GHz can be achieved for QCLs at 4.6 μm and 9 μm, respectively, with an injection ratio of 5 dB. The result also shows that an ultrawide modulation bandwidth of more than 200 GHz is possible with a 10 dB injection ratio for QCLs at 9 μm. An important characteristic of injection-locked QCLs is the nonexistence of unstable locking region in the locking map, in contrast to their diode laser counterparts. We attribute this to the ultra-short upper laser state lifetimes of QCLs.

  7. Indirect high-bandwidth stabilization of carrier-envelope phase of a high-energy, low-repetition-rate laser.

    PubMed

    Fu, Yuxi; Takahashi, Eiji J; Midorikawa, Katsumi

    2016-06-13

    We demonstrate a method of stabilizing the carrier-envelope phase (CEP) of low-repetition-rate, high-energy femtosecond laser systems such as TW-PW class lasers. A relatively weak high-repetition-rate (~1 kHz) reference pulse copropagates with a low-repetition-rate (10 Hz) high-energy pulse, which are s- and p-polarized, respectively. Using a Brewster angle window, the reference pulse is separated after the power amplifier and used for feedback to stabilize its CEP. The single-shot CEP of the high-energy pulse is indirectly stabilized to 550 mrad RMS, which is the highest CEP stability ever reported for a low-repetition-rate (10-Hz) high-energy laser system. In this novel method, the feedback frequency of the reference pulse from the front-end preamplifier can be almost preserved. Thus, higher CEP stability can be realized than for lower frequencies. Of course, a reference pulse with an even higher repetition rate (e.g., 10 kHz) can be easily employed to sample and feed back CEP jitter over a broader frequency bandwidth. PMID:27410345

  8. Design of red-emitting external cavity diode laser module for high-slope efficiency and narrow bandwidth

    NASA Astrophysics Data System (ADS)

    Park, Jiyeon; Song, Hong Joo; Na, Hong Man; Lee, Jun Ho; Yun, Ilgu

    2015-09-01

    A red-emitting external cavity diode laser (ECDL) module was designed to increase the slope efficiency and reduce the bandwidth by tilting the solitary laser diode (LD) 90 deg. This tilt resulted in parallel polarization, which yielded high-slope efficiency and also produced a favorable geometry that minimized the area of the back-focused beam, thereby facilitating selection of a specific wavelength. A ray-tracing simulator was used to optimize optical parameters such as the back focal length of the collimating lens, the cavity length, and the grating's groove density. Based on the optimized structure, an ECDL module package was designed for thermal control by using autodisk computer-aided design tool. The resulting module obtained high-slope efficiency and narrow-bandwidth emission of red light, making it suitable for potential application as a light source for a commercial three-dimensional holographic system. The module achieved the narrow bandwidth of 80 pm and the slope efficiency of 0.81 W/A, which compared favorably with the output power of 0.8 to 0.9 W/A of commercial solitary LDs.

  9. Modeling the dynamically tuned gyroscope in support of high-bandwidth capture loop design

    NASA Astrophysics Data System (ADS)

    May, David

    1999-07-01

    The 'dynamic tuning' of a dynamically tuned gyroscope (DTG) refers to a clever gimbal configuration that balances the torques from the support flexures with dynamic spring torques created by gimbal 'flutter' while the gyro rotor spins. This configuration allows the gyro rotor to spin to a 'free' rotor in two axes. The dynamics of a free rotor are widely known and easily summarized in the right-hand rule for gyro precession and a simple second order system equation with a natural frequency, known as the nutation frequency, as a function of the angular momentum and transverse inertia. Not much more is needed for design of capture loops for the DTG, as long as the bandwidth of the capture loop does not approach the nutation frequency of the gyro. However, the complete dynamical equations of motion of the DTG include other parameters such as windage, mistuning and friction torques that must be considered when designing capture loops with higher than nominal bandwidths. These equations, which are well known and widely published, are discussed in regard to capture loop design. The application of active nutation damping in the capture loop compensation is outlined. Typically results are presented.

  10. A novel ±0.8 V high-performance voltage-tunable CDTA with enhanced bandwidth

    NASA Astrophysics Data System (ADS)

    Xia, Zanming; Wang, Chunhua; Kuang, Jun; Jin, Jie

    2016-04-01

    In this article, we propose a novel high-performance complementary metal oxide semiconductor (CMOS) current differencing transconductance amplifier (CDTA) with a transconductance gain (GM) that can be linearly tuned by a voltage. By using a high-speed, low-voltage, cascaded current mirror active resistance compensation technique, the proposed CDTA circuit exhibits wide frequency bandwidths, high current tracking precisions as well as large output impedances. The linear-tunable GM of the CDTA is designed with the use of linear composite metal oxide semiconductor field-effect transistor as basic cells in the circuit. Combining these two approaches, several design concerns are studied, including: impedance characteristic, tracking errors, offset and linearity and noise. The prototype chip with a 0.25 mm2 area is fabricated in a GlobalFoundries'0.18 μm CMOS process. The simulated results and measured results with ±0.8 V DC supply voltages are presented, and show extremely wide bandwidths and wide linear tuning range. In addition, a fully differential band-pass filter for a high-speed system is also given as an example to confirm the high performance of the proposed circuit.

  11. A 15 MHz bandwidth, 60 V{sub pp}, low distortion power amplifier for driving high power piezoelectric transducers

    SciTech Connect

    Capineri, Lorenzo

    2014-10-01

    This paper presents the design and the realization of a linear power amplifier with large bandwidth (15 MHz) capable of driving low impedance ultrasonic transducers. The output current driving capability (up to 5 A) and low distortion makes it suitable for new research applications using high power ultrasound in the medical and industrial fields. The electronic design approach is modular so that the characteristics can be scaled according to specific applications and implementation details for the circuit layout are reported. Finally the characterization of the power amplifier module is presented.

  12. Wireless, High-Bandwidth Recordings from Non-Human Primate Motor Cortex using a Scalable 16-Ch Implantable Microsystem

    PubMed Central

    Borton, David A.; Song, Yoon-Kyu; Patterson, William R.; Bull, Christopher W.; Park, Sunmee; Laiwalla, Farah; Donoghue, John P.; Nurmikko, Arto V.

    2013-01-01

    A multitude of neuroengineering challenges exist today in creating practical, chronic multichannel neural recording systems for primate research and human clinical application. Specifically, a) the persistent wired connections limit patient mobility from the recording system, b) the transfer of high bandwidth signals to external (even distant) electronics normally forces premature data reduction, and c) the chronic susceptibility to infection due to the percutaneous nature of the implants all severely hinder the success of neural prosthetic systems. Here we detail one approach to overcome these limitations: an entirely implantable, wirelessly communicating, integrated neural recording microsystem, dubbed the Brain Implantable Chip (BIC). PMID:19964128

  13. Glass-embedded two-dimensional silicon photonic crystal devices with a broad bandwidth waveguide and a high quality nanocavity.

    PubMed

    Jeon, Seung-Woo; Han, Jin-Kyu; Song, Bong-Shik; Noda, Susumu

    2010-08-30

    To enhance the mechanical stability of a two-dimensional photonic crystal slab structure and maintain its excellent performance, we designed a glass-embedded silicon photonic crystal device consisting of a broad bandwidth waveguide and a nanocavity with a high quality (Q) factor, and then fabricated the structure using spin-on glass (SOG). Furthermore, we showed that the refractive index of the SOG could be tuned from 1.37 to 1.57 by varying the curing temperature of the SOG. Finally, we demonstrated a glass-embedded heterostructured cavity with an ultrahigh Q factor of 160,000 by adjusting the refractive index of the SOG. PMID:20940831

  14. Wide-Bandwidth, Wide-Beamwidth, High-Resolution, Millimeter-Wave Imaging for Concealed Weapon Detection

    SciTech Connect

    Sheen, David M.; Fernandes, Justin L.; Tedeschi, Jonathan R.; McMakin, Douglas L.; Jones, Anthony M.; Lechelt, Wayne M.; Severtsen, Ronald H.

    2013-06-12

    Active millimeter-wave imaging is currently being used for personnel screening at airports and other high-security facilities. The lateral resolution, depth resolution, clothing penetration, and image illumination quality obtained from next-generation systems can be significantly enhanced through the selection the aperture size, antenna beamwidth, center frequency, and bandwidth. In this paper, the results of an extensive imaging trade study are presented using both planar and cylindrical three-dimensional imaging techniques at frequency ranges of 10-20 GHz, 10 – 40 GHz, 40 – 60 GHz, and 75 – 105 GHz

  15. High-bandwidth Modulation of H2/Syngas Fuel to Control Combustion Dynamics in Micro-Mixing Lean Premix Systems

    SciTech Connect

    Jeff Melzak; Tim Lieuwen; Adel Mansour

    2012-01-31

    The goal of this program was to develop and demonstrate fuel injection technologies that will facilitate the development of cost-effective turbine engines for Integrated Gasification Combined Cycle (IGCC) power plants, while improving efficiency and reducing emissions. The program involved developing a next-generation multi-point injector with enhanced stability performance for lean premix turbine systems that burn hydrogen (H2) or synthesis gas (syngas) fuels. A previously developed injector that demonstrated superior emissions performance was improved to enhance static flame stability through zone staging and pilot sheltering. In addition, piezo valve technology was implemented to investigate the potential for enhanced dynamic stability through high-bandwidth modulation of the fuel supply. Prototype injector and valve hardware were tested in an atmospheric combustion facility. The program was successful in meeting its objectives. Specifically, the following was accomplished: Demonstrated improvement of lean operability of the Parker multi-point injector through staging of fuel flow and primary zone sheltering; Developed a piezo valve capable of proportional and high-bandwidth modulation of gaseous fuel flow at frequencies as high as 500 Hz; The valve was shown to be capable of effecting changes to flame dynamics, heat release, and acoustic signature of an atmospheric combustor. The latter achievement indicates the viability of the Parker piezo valve technology for use in future adaptively controlled systems for the mitigation of combustion instabilities, particularly for attenuating combustion dynamics under ultra-lean conditions.

  16. Adventures in the evolution of a high-bandwidth network for central servers

    SciTech Connect

    Swartz, K.L.; Cottrell, L.; Dart, M.

    1994-08-01

    In a small network, clients and servers may all be connected to a single Ethernet without significant performance concerns. As the number of clients on a network grows, the necessity of splitting the network into multiple sub-networks, each with a manageable number of clients, becomes clear. Less obvious is what to do with the servers. Group file servers on subnets and multihomed servers offer only partial solutions -- many other types of servers do not lend themselves to a decentralized model, and tend to collect on another, well-connected but overloaded Ethernet. The higher speed of FDDI seems to offer an easy solution, but in practice both expense and interoperability problems render FDDI a poor choice. Ethernet switches appear to permit cheaper and more reliable networking to the servers while providing an aggregate network bandwidth greater than a simple Ethernet. This paper studies the evolution of the server networks at SLAC. Difficulties encountered in the deployment of FDDI are described, as are the tools and techniques used to characterize the traffic patterns on the server network. Performance of Ethernet, FDDI, and switched Ethernet networks is analyzed, as are reliability and maintainability issues for these alternatives. The motivations for re-designing the SLAC general server network to use a switched Ethernet instead of FDDI are described, as are the reasons for choosing FDDI for the farm and firewall networks at SLAC. Guidelines are developed which may help in making this choice for other networks.

  17. High Bandwidth Analog Applications Of Photonics: Present Capabilities And Future Possibilities

    NASA Astrophysics Data System (ADS)

    Roeske, F.

    1987-03-01

    Experimenters involved in measuring single-shot, fast-transient phenomena are fast turning toward photonics to meet their experimental needs. Photonics is the technology of generating and using light in detection, diagnostics, communications, and information processing systems. This technology includes light generation, transmission, deflection, amplification, detection, and recording and includes areas of lasers and other light sources, fiber optics, electro-optical instrumentation, and optical components and instrumentation. Photonics systems offer immense advantages and possibilities over ,Systems that use electrical signals. The advantages realized by photonics systems include increased data quality (in terms of bandwidth, resolution, reliability, and often accuracy and precision), increased data quantity, and economic and operational benefits. Single-shot, fast--transient analog measurement techniques introduce some special considerations and challenges for the experimenter that are not encountered in telecommunication applications of photonics. This overview explores some of these issues with emphasis placed on photonic sensors and data recorders. A sampling of photonics diagnostic systems is presented along with a discussion of future possibilities and challenges facing the experimenter. This exciting new field is in its infancy, and many of the diagnostic techniques presented are still evolving into yet more powerful tools for the experimenter. Single-shot, fast-transient analog photonics diagnostic techniques have experienced an almost exponential growth over the past few years and are expected to have a major impact on governmental, industrial, and academic communities involved with such measurements.

  18. High-bandwidth multimode self-sensing in bimodal atomic force microscopy

    PubMed Central

    Moheimani, S O Reza

    2016-01-01

    Summary Using standard microelectromechanical system (MEMS) processes to coat a microcantilever with a piezoelectric layer results in a versatile transducer with inherent self-sensing capabilities. For applications in multifrequency atomic force microscopy (MF-AFM), we illustrate that a single piezoelectric layer can be simultaneously used for multimode excitation and detection of the cantilever deflection. This is achieved by a charge sensor with a bandwidth of 10 MHz and dual feedthrough cancellation to recover the resonant modes that are heavily buried in feedthrough originating from the piezoelectric capacitance. The setup enables the omission of the commonly used piezoelectric stack actuator and optical beam deflection sensor, alleviating limitations due to distorted frequency responses and instrumentation cost, respectively. The proposed method benefits from a more than two orders of magnitude increase in deflection to strain sensitivity on the fifth eigenmode leading to a remarkable signal-to-noise ratio. Experimental results using bimodal AFM imaging on a two component polymer sample validate that the self-sensing scheme can therefore be used to provide both the feedback signal, for topography imaging on the fundamental mode, and phase imaging on the higher eigenmode. PMID:26977385

  19. VCSEL arrays for high-aggregate bandwidth of up to 1.34 Tbps

    NASA Astrophysics Data System (ADS)

    Grabherr, Martin; Intemann, Steffan; King, Roger; Wabra, Stefan; Jäger, Roland; Riedl, Michael

    2014-02-01

    Even though the lane speed of VCSEL based AOC and transceivers has reached 25 Gbps and beyond [1-7], parallel optics are getting even more important in order to meet the increasing demand for aggregate bandwidths in upcoming applications, among others, 100 Gigabit Ethernet, Infiniband EDR, or EOM (embedded optical modules). As 100 Gbps can be achieved by, e.g., 4 times 25 Gbps using standard QSFP form factor, different approaches are using large scale 2D VCSEL arrays operating at lower lane speeds. Early work on 2D VCSEL based transceivers has already been presented beginning of this century [8] and recent work also addressed the potential of this technology [9,10]. In 2013, Compass EOS has introduced a 1.34 Tbps core router solution [11,12,13] that incorporates 2D VCSEL arrays of 14x12 emitters designed and manufactured by Philips U-L-M Photonics. The VCSEL array is mounted face down onto a CMOS ASIC, directly on top of the analog area. The emission wavelength of 1000 nm allows for substrate side emission and thus for flip-chip mounting as well as the possibility of integrating 2D microlens arrays onto the stack of CMOS and VCSEL array. After briefly introducing the router with regard to the incorporated VCSEL technology we discuss the design and performance of the VCSEL array. Finally, the assembly solution for this most compact and dense transceiver solution is presented.

  20. Technologies for low-bandwidth high-latency unmanned ground vehicle control

    NASA Astrophysics Data System (ADS)

    Pace, Teresa; Cogan, Ken; Hunt, Lee; Restine, Paul

    2014-05-01

    Automation technology has evolved at a rapid pace in recent years; however, many real-world problems require contextual understanding, problem solving, and other forms of higher-order thinking that extends beyond the capabilities of robots for the foreseeable future. This limits the complexity of automation which can be supplied to modern unmanned ground robots (UGV) and necessitates human-in-the-loop monitoring and control for some portions of missions. In order for the human operator to make decisions and provide tasking during key portions of the mission, existing solutions first derive significant information from a potentially dense reconstruction of the scene utilizing LIDAR, video, and other onboard sensors. A dense reconstruction contains too much data for real-time transmission over a modern wireless data link, so the robot electronics must first condense the scene representation prior to transmission. The control station receives this condensed scene representations and provides visual information to the human operator; the human operator then provides tele-operation commands in real-time to the robot. This paper discusses approaches to dense scene reduction of the data required to transmit to a human-in-the loop as well as the challenges associated with them. In addition, the complex and unstructured nature of real-world environments increases the need for tele-operation. Furthermore, many environments reduce the bandwidth and increase the latency of the link. Ultimately, worsening conditions will cause the tele-operation control process to break down, rendering the robot ineffective. In a worst-case scenario, extreme conditions causing a complete loss-of-communications could result in mission failure and loss of the vehicle.

  1. Low-bandwidth authentication.

    SciTech Connect

    Donnelly, Patrick Joseph; McIver, Lauren; Gaines, Brian R.; Anderson, Erik; Collins, Michael Joseph; Thomas,Kurt Adam; McDaniel, Austin

    2007-09-01

    Remotely-fielded unattended sensor networks generally must operate at very low power--in the milliwatt or microwatt range--and thus have extremely limited communications bandwidth. Such sensors might be asleep most of the time to conserve power, waking only occasionally to transmit a few bits. RFID tags for tracking or material control have similarly tight bandwidth constraints, and emerging nanotechnology devices will be even more limited. Since transmitted data is subject to spoofing, and since sensors might be located in uncontrolled environments vulnerable to physical tampering, the high-consequence data generated by such systems must be protected by cryptographically sound authentication mechanisms; but such mechanisms are often lacking in current sensor networks. One reason for this undesirable situation is that standard authentication methods become impractical or impossible when bandwidth is severely constrained; if messages are small, a standard digital signature or HMAC will be many times larger than the message itself, yet it might be possible to spare only a few extra bits per message for security. Furthermore, the authentication tags themselves are only one part of cryptographic overhead, as key management functions (distributing, changing, and revoking keys) consume still more bandwidth. To address this problem, we have developed algorithms that provide secure authentication while adding very little communication overhead. Such techniques will make it possible to add strong cryptographic guarantees of data integrity to a much wider range of systems.

  2. Space bandwidth product enhancement of holographic display using high-order diffraction guided by holographic optical element.

    PubMed

    Li, Gang; Jeong, Jinsoo; Lee, Dukho; Yeom, Jiwoon; Jang, Changwon; Lee, Seungjae; Lee, Byoungho

    2015-12-28

    A space bandwidth product (SBP) enhancement method for holographic display using high-order diffraction of a spatial light modulator (SLM) is proposed. Among numerous high order diffraction terms, the plus-minus first and the zeroth are adopted and guided by holographic optical elements (HOEs) to an identical direction with the same intensity. By using a set of electro-shutters synchronized with corresponding order component, the system acts as if three SLMs are tiled in the horizontal direction. To confirm the feasibility of using HOE as the guiding optics for the system, several optical characteristics of the recording material are measured before using them. Furthermore, a computer generated hologram algorithm is proposed for compensating the wavefront distortion caused by use of the HOE. The demonstrated system achieves a three-fold increase in SBP of a single SLM. The results are verified experimentally. PMID:26831985

  3. Bandwidth reduction of high-frequency sonar imagery in shallow water using content-adaptive hybrid image coding

    NASA Astrophysics Data System (ADS)

    Shin, Frances B.; Kil, David H.

    1998-09-01

    One of the biggest challenges in distributed underwater mine warfare for area sanitization and safe power projection during regional conflicts is transmission of compressed raw imagery data to a central processing station via a limited bandwidth channel while preserving crucial target information for further detection and automatic target recognition processing. Moreover, operating in an extremely shallow water with fluctuating channels and numerous interfering sources makes it imperative that image compression algorithms effectively deal with background nonstationarity within an image as well as content variation between images. In this paper, we present a novel approach to lossy image compression that combines image- content classification, content-adaptive bit allocation, and hybrid wavelet tree-based coding for over 100:1 bandwidth reduction with little sacrifice in signal-to-noise ratio (SNR). Our algorithm comprises (1) content-adaptive coding that takes advantage of a classify-before-coding strategy to reduce data mismatch, (2) subimage transformation for energy compaction, and (3) a wavelet tree-based coding for efficient encoding of significant wavelet coefficients. Furthermore, instead of using the embedded zerotree coding with scalar quantization (SQ), we investigate the use of a hybrid coding strategy that combines SQ for high-magnitude outlier transform coefficients and classified vector quantization (CVQ) for compactly clustered coefficients. This approach helps us achieve reduced distortion error and robustness while achieving high compression ratio. Our analysis based on the high-frequency sonar real data that exhibit severe content variability and contain both mines and mine-like clutter indicates that we can achieve over 100:1 compression ratio without losing crucial signal attributes. In comparison, benchmarking of the same data set with the best still-picture compression algorithm called the set partitioning in hierarchical trees (SPIHT) reveals

  4. High-Bandwidth Atomic Force Microscopy Reveals A Mechanical spike Accompanying the Action Potential in mammalian Nerve Terminals

    NASA Astrophysics Data System (ADS)

    Salzberg, Brian M.

    2008-03-01

    Information transfer from neuron to neuron within nervous systems occurs when the action potential arrives at a nerve terminal and initiates the release of a chemical messenger (neurotransmitter). In the mammalian neurohypophysis (posterior pituitary), large and rapid changes in light scattering accompany secretion of transmitter-like neuropeptides. In the mouse, these intrinsic optical signals are intimately related to the arrival of the action potential (E-wave) and the release of arginine vasopressin and oxytocin (S-wave). We have used a high bandwidth (20 kHz) atomic force microscope (AFM) to demonstrate that these light scattering signals are associated with changes in nerve terminal volume, detected as nanometer-scale movements of a cantilever positioned on top of the neurohypophysis. The most rapid mechanical response, the ``spike'', has duration comparable to that of the action potential (˜2 ms) and probably reflects an increase in terminal volume due to H2O movement associated with Na^+-influx. Elementary calculations suggest that two H2O molecules accompanying each Na^+-ion could account for the ˜0.5-1.0 å increase in the diameter of each terminal during the action potential. Distinguishable from the mechanical ``spike'', a slower mechanical event, the ``dip'', represents a decrease in nerve terminal volume, depends upon Ca^2+-entry, as well as on intra-terminal Ca^2+-transients, and appears to monitor events associated with secretion. A simple hypothesis is that this ``dip'' reflects the extrusion of the dense core granule that comprises the secretory products. These dynamic high bandwidth AFM recordings are the first to monitor mechanical events in nervous systems and may provide novel insights into the mechanism(s) by which excitation is coupled to secretion at nerve terminals.

  5. FPGA Flash Memory High Speed Data Acquisition

    NASA Technical Reports Server (NTRS)

    Gonzalez, April

    2013-01-01

    The purpose of this research is to design and implement a VHDL ONFI Controller module for a Modular Instrumentation System. The goal of the Modular Instrumentation System will be to have a low power device that will store data and send the data at a low speed to a processor. The benefit of such a system will give an advantage over other purchased binary IP due to the capability of allowing NASA to re-use and modify the memory controller module. To accomplish the performance criteria of a low power system, an in house auxiliary board (Flash/ADC board), FPGA development kit, debug board, and modular instrumentation board will be jointly used for the data acquisition. The Flash/ADC board contains four, 1 MSPS, input channel signals and an Open NAND Flash memory module with an analog to digital converter. The ADC, data bits, and control line signals from the board are sent to an Microsemi/Actel FPGA development kit for VHDL programming of the flash memory WRITE, READ, READ STATUS, ERASE, and RESET operation waveforms using Libero software. The debug board will be used for verification of the analog input signal and be able to communicate via serial interface with the module instrumentation. The scope of the new controller module was to find and develop an ONFI controller with the debug board layout designed and completed for manufacture. Successful flash memory operation waveform test routines were completed, simulated, and tested to work on the FPGA board. Through connection of the Flash/ADC board with the FPGA, it was found that the device specifications were not being meet with Vdd reaching half of its voltage. Further testing showed that it was the manufactured Flash/ADC board that contained a misalignment with the ONFI memory module traces. The errors proved to be too great to fix in the time limit set for the project.

  6. High-bandwidth 1.55 {micro}m waveguide integrated photodetector

    SciTech Connect

    Unterboersch, G.; Trommer, D.; Umbach, A.; Mekonnen, G.G.

    1996-12-31

    The authors present an InP based pin-photodetector with an integrated passive optical waveguide using evanescent field coupling for operation in the wavelength around 1.55 {micro}m. The passivated devices are fabricated employing a single MOVPE run and a self-aligned metallization process in order to achieve reduced series resistances. They are monolithically integrable in photonic integrated circuits with optical functionality as well as with high-speed electronic amplifier circuits. The detector exhibits a polarization insensitive internal quantum efficiency of about 90% and a transit time limited high-speed behavior. The electrical cut-off frequency amounts to 45 GHz and is maintained up to high input power levels.

  7. Development of Advanced Low Emission Injectors and High-Bandwidth Fuel Flow Modulation Valves

    NASA Technical Reports Server (NTRS)

    Mansour, Adel

    2015-01-01

    Parker Hannifin Corporation developed the 3-Zone fuel nozzle for NASA's Environmentally Responsible Aviation Program to meet NASAs target of 75 LTO NOx reduction from CAEP6 regulation. The nozzle concept was envisioned as a drop-in replacement for currently used fuel nozzle stem, and is built up from laminates to provide energetic mixing suitable for lean direct injection mode at high combustor pressure. A high frequency fuel valve was also developed to provide fuel modulation for the pilot injector. Final testing result shows the LTO NOx level falling just shy of NASAs goal at 31.

  8. Design of a demonstration experiment on the wide-bandwidth high-power dielectric Cherenkov maser amplifier

    SciTech Connect

    Harin, V.; Melnikov, G.; Shlapapkovskii, A.

    1995-12-31

    Bandwidth dependences on the parameters of an electron beam and dielectric-fined waveguide have been calculated from the system dispersion relation, and the optimal set of parameters yielding large value of the bandwidth has been chosen. One-dimensional nonlinear simulations have been carried out. The output power of 60 MW at the peak gain of 27 dB is planned to be achieved. The wide-bandwidth input coupler has been constructed, and the results of microwave transmission measurements through the no-beam system are presented.

  9. High flux, narrow bandwidth compton light sources via extended laser-electron interactions

    DOEpatents

    Barty, V P

    2015-01-13

    New configurations of lasers and electron beams efficiently and robustly produce high flux beams of bright, tunable, polarized quasi-monoenergetic x-rays and gamma-rays via laser-Compton scattering. Specifically, the use of long-duration, pulsed lasers and closely-spaced, low-charge and low emittance bunches of electron beams increase the spectral flux of the Compton-scattered x-rays and gamma rays, increase efficiency of the laser-electron interaction and significantly reduce the overall complexity of Compton based light sources.

  10. Wide bandwidth and high resolution planar filter array based on DBR-metasurface-DBR structures

    NASA Astrophysics Data System (ADS)

    Horie, Yu; Arbabi, Amir; Arbabi, Ehsan; Kamali, Seyedeh Mahsa; Faraon, Andrei

    2016-05-01

    We propose and experimentally demonstrate a planar array of optical bandpass filters composed of low loss dielectric metasurface layers sandwiched between two distributed Bragg reflectors (DBRs). The two DBRs form a Fabry-P\\'erot resonator whose center wavelength is controlled by the design of the transmissive metasurface layer which functions as a phase shifting element. We demonstrate an array of bandpass filters with spatially varying center wavelengths covering a wide range of operation wavelengths of 250 nm around {\\lambda} = 1550 nm ({\\Delta}{\\lambda}/{\\lambda} = 16%). The center wavelengths of each filter are independently controlled only by changing the in-plane geometry of the sandwiched metasurfaces, and the experimentally measured quality factors are larger than 700. The demonstrated filter array can be directly integrated on top of photodetector arrays to realize on-chip high-resolution spectrometers with free-space coupling.

  11. Wide bandwidth and high resolution planar filter array based on DBR-metasurface-DBR structures.

    PubMed

    Horie, Yu; Arbabi, Amir; Arbabi, Ehsan; Kamali, Seyedeh Mahsa; Faraon, Andrei

    2016-05-30

    We propose and experimentally demonstrate a planar array of optical bandpass filters composed of low loss dielectric metasurface layers sandwiched between two distributed Bragg reflectors (DBRs). The two DBRs form a Fabry-Pérot resonator whose center wavelength is controlled by the design of the transmissive metasurface layer which functions as a phase shifting element. We demonstrate an array of bandpass filters with spatially varying center wavelengths covering a wide range of operation wavelengths of 250nm around λ = 1550nm (Δλ/λ = 16%). The center wavelengths of each filter are independently controlled only by changing the in-plane geometry of the sandwiched metasurfaces, and the experimentally measured quality factors are larger than 700. The demonstrated filter array can be directly integrated on top of photodetector arrays to realize on-chip high-resolution spectrometers with free-space coupling. PMID:27410093

  12. Development of Radiation-Tolerant, Low Mass, High Bandwidth Flexible Printed Circuit Cables for Particle Detection Applications

    NASA Astrophysics Data System (ADS)

    McFadden, Neil

    2016-03-01

    Design options for meter long flexible printed circuit cables required for low mass ultra-high speed signal transmission in the high radiation environment at the High Luminosity run of the Large Hadron Collider (LHC) are described. Two dielectric materials were considered in this study, Kapton and a Kapton/Teflon mixture. The design geometry is a differential embedded microstrip with nominal 100 Ω impedance. Minimal mass and maximal radiation hardness are pre-eminent considerations. The long flexible printed circuit cables are characterized in bit error rate tests (BERT), attenuation versus frequency, mechanical response to stress and temperature change, and RLC decomposition. These tests are performed before and after irradiation with 1 MeV neutrons to 2x1016/cm 2 and 800 MeV protons to 2x1016 1 MeV-neq/cm2. A 1.0 m Kapton cable, with bandwidth of 6.22 gigabits per second, 0.03% of a radiation length, and no radiation induced mechanical or electrical degradation is obtained.

  13. Low-Complexity, High-Performance Bandwidth Efficient Coding and Coded Modulation Techniques for Satellite and Space Communications

    NASA Technical Reports Server (NTRS)

    Costello, Daniel J., Jr.

    1993-01-01

    The semi-annual progress report for NASA grant NAG5-557 is presented. The report contains three papers concerning bandwidth efficient coding and coded modulation techniques for satellite and space communications.

  14. 3D interconnect architecture for high-bandwidth massively paralleled imager

    NASA Astrophysics Data System (ADS)

    Kwiatkowski, K.; Lyke, J. C.; Wojnarowski, R. J.; Beche, J.-F.; Fillion, R.; Kapusta, C.; Millaud, J.; Saia, R.; Wilke, M. D.

    2003-08-01

    The proton radiography group at LANL is developing a fast (5×10 6 frames/s or 5 megaframe/s) multi-frame imager for use in dynamic radiographic experiments with high-energy protons. The mega-pixel imager will acquire and process a burst of 32 frames captured at inter-frame time ˜200 ns. Real time signal processing and storage requirements for entire frames, of rapidly acquired pixels impose severe demands on the space available for the electronics in a standard monolithic approach. As such, a 3D arrangement of detector and circuit elements is under development. In this scheme, the readout integrated circuits (ROICs) are stacked vertically (like playing cards) into a cube configuration. Another die, a fully depleted pixel photo-diode focal plane array (FPA), is bump bonded to one of the edge surfaces formed by the resulting ROIC cube. Recently, an assembly of the proof-of-principle test cube and sensor has been completed.

  15. High bandwidth linear viscoelastic properties of complex fluids from the measurement of their free surface fluctuations

    NASA Astrophysics Data System (ADS)

    Pottier, Basile; Talini, Laurence; Frétigny, Christian

    2012-02-01

    We present a new optical method to measure the linear viscoelastic properties of materials, ranging from complex fluids to soft solids, within a large frequency range (about 0.1--10^4 Hz). The surface fluctuation specular reflection technique is based on the measurement of the thermal fluctuations of the free surfaces of materials at which a laser beam is specularly reflected. The propagation of the thermal surface waves depends on the surface tension, density, and complex viscoelastic modulus of the material. For known surface tension and density, we show that the frequency dependent elastic and loss moduli can be deduced from the fluctuation spectrum. Using a viscoelastic solid (a cross-linked PDMS), which linear viscoelastic properties are known in a large frequency range from rheometric measurements and the time--temperature superposition principle, we show that there is a good agreement between the rheological characterization provided by rheometric and fluctuation measurements. We also present measurements conducted with complex fluids that are supramolecular polymer solutions. The agreement with other low frequency and high frequency rheological measurements is again very good, and we discuss the sensitivity of the technique to surface viscoelasticity.

  16. A Novel Multi-carrier Radar for High-speed Wide-bandwidth Stepped-Frequency GPR

    NASA Astrophysics Data System (ADS)

    Kyoo Kim, Dong; Choi, Young Woo; Kang, Do Wook

    2015-04-01

    Ground Penetrating Radar (GPR) is one of the non-destructive testing methods for studying underground situations by using the electro-magnetic wave radiation effect. Two classical sensing techniques, impulsive GPR and stepped-frequency GPR, are used for a long time in various GPR applications. Signal bandwidths generated by the two techniques ranges from several hundred MHz to several GHz. For the research area of pavement survey the surveying speed is emphasized, thus impulsive GPR has been preferred to stepped-frequency GPR. To make a complete single scan operation, stepped-frequency GPR needs over hundreds of different frequency continuous wave (CW) radiations within its signal bandwidth which is the main time taking process. In case of impulsive GPR, it needs also several repeated pulses, for example from 64 to 512 repeated pulses, to do a complete single scan operation. Although the two techniques need several repeated internal operation processes, impulsive GPR is generally considered to be fast than stepped-frequency GPR. On the other hand, many studies of stepped-frequency GPR emphasizes that high-resolution scanning accuracy can be achieved by controlling each frequency component differently, such as frequency power profile, flexible bandwidth control. In case of pavement survey area, high-accuracy scanning is required within one meter deep as well as high-speed survey. The required accuracy is up to several centimeter in the material where dielectric constant is about 10. When surveying pavement, multi-element array antenna gives advantages to the measurement accuracy enhancement, where the scanning region of a 3 meters wide paved road is divided into several sub-regions as the number of the antenna element. For example, when stepped-frequency GPR requires 6msec for single scan operation and 15-element antenna is considered, the survey speed is limited to 15km/h in order to scan the road every 5cm, which is slow compared with common driving condition on

  17. Implementation of High Speed Distributed Data Acquisition System

    NASA Astrophysics Data System (ADS)

    Raju, Anju P.; Sekhar, Ambika

    2012-09-01

    This paper introduces a high speed distributed data acquisition system based on a field programmable gate array (FPGA). The aim is to develop a "distributed" data acquisition interface. The development of instruments such as personal computers and engineering workstations based on "standard" platforms is the motivation behind this effort. Using standard platforms as the controlling unit allows independence in hardware from a particular vendor and hardware platform. The distributed approach also has advantages from a functional point of view: acquisition resources become available to multiple instruments; the acquisition front-end can be physically remote from the rest of the instrument. High speed data acquisition system transmits data faster to a remote computer system through Ethernet interface. The data is acquired through 16 analog input channels. The input data commands are multiplexed and digitized and then the data is stored in 1K buffer for each input channel. The main control unit in this design is the 16 bit processor implemented in the FPGA. This 16 bit processor is used to set up and initialize the data source and the Ethernet controller, as well as control the flow of data from the memory element to the NIC. Using this processor we can initialize and control the different configuration registers in the Ethernet controller in a easy manner. Then these data packets are sending to the remote PC through the Ethernet interface. The main advantages of the using FPGA as standard platform are its flexibility, low power consumption, short design duration, fast time to market, programmability and high density. The main advantages of using Ethernet controller AX88796 over others are its non PCI interface, the presence of embedded SRAM where transmit and reception buffers are located and high-performance SRAM-like interface. The paper introduces the implementation of the distributed data acquisition using FPGA by VHDL. The main advantages of this system are high

  18. Pushing the Envelope: Ship to Shore Events and High-Bandwidth Telepresence Engages Scientists and the Public

    NASA Astrophysics Data System (ADS)

    Cooper, S. K.; Coleman, D. F.; Fisher, A. T.; Livelybrooks, D.; Mulder, G.

    2013-12-01

    Since 2009, the drillship JOIDES Resolution has engaged in an extensive program of live ship-to-shore events during its two-month scientific expeditions using a range of software applications and formats. The University of Rhode Island's Inner Space Center has utilized a high bandwidth 'telepresence' from ships such as the Ocean Exploration Trust's E/V Nautilus and the NOAA Ship Okeanos Explorer, to bring live feeds from underwater exploration vehicles directly into museums, aquaria, science centers, boys and girls clubs, and K-16 classrooms. Both of these strategies have employed close partnerships between scientists and educators to bring cutting edge research and the excitement of exploration and discovery directly to the public in close to real time, but telepresence provides unique opportunities. Participants have been able to experience, live, launches of remotely operated vehicle systems including Jason/Medea on R/V Atlantis and Hercules/Argus on Nautilus, see scientific samples come up on deck for the very first time, observe previously-undiscovered shipwrecks at the same time as those on ship, and watch amazing deep sea creatures swim past deep water cameras. There are many benefits from high-bandwidth telepresence, including improved quality of images, video, and sound; the ability to move large data sets and files between ship and shore, allowing collaboration among individuals who are not on the ship; the ability to stage spontaneous "web events" among scientific, educational, and technical personnel at essentially any time; and more intensive interactions through use of social media, such as blogging, posting of multimedia products, and frequent question/answer sessions. These telepresence-enhanced activities assist the public in understanding the significance and excitement of these discoveries, the challenges of working in the deep sea, and the true nature of scientific processes. These interactions have significant impacts on their audiences, and

  19. High Bandwidth, Multi-Purpose Passive Radar Receiver Design For Aerospace and Geoscience Targets

    NASA Astrophysics Data System (ADS)

    Vertatschitsch, Laura

    uninterruptible power supply (UPS) for up to 1 hour of continuous operation. In this document we provide technical details of the hardware, firmware, and software of the system and design strategies and decisions. We cover the topic of coherent processing for passive radar, specifically an overview of the cross-ambiguity function as a detection mechanism. While the applications of a system like this are incredibly broad, the initial validation and performance analysis was applied specifically to detection of aircraft using Digital Television (DTV) broadcast as an illuminator. We present results of both stationary and mobile operation. In stationary operation, the same helicopter has been detected using two different DTV transmissions. Early mobile operation results show the Doppler-spread ground clutter and possible detection of aircraft. In addition to the fully-functional aircraft detection signal chain, alternative FPGA designs are presented with modes for fast sampling on two antennas or four antennas, with access to an aggregate 240 MHz of spectrum, with 8-bit samples. At these extremely high data rates, moderate data loss occurs while saving this data to disk, but as detailed within this document, it can be accounted for and the effects minimalized, still allowing for detection of aircraft. With these modes, FM transmission and DTV transmission can be captured synchronously from a single antenna and digitizer feed, an exciting result that offers promise for both aerospace and geoscience applications.

  20. Relative loudness of low- and high-frequency bands of speech-shaped babble, including the influence of bandwidth and input level

    NASA Astrophysics Data System (ADS)

    Keidser, Gitte; Katsch, Richard; Dillon, Harvey; Grant, Frances

    2002-02-01

    In a balancing test, ten normal-hearing listeners adjusted filtered speech-shaped babble-noise to equally loud levels. On average, they selected about 10 dB less gain for bands below 1 kHz than for bands above and including 1 kHz. The findings applied to two bandwidths (octave and equivalent rectangular bandwidth) and two levels (65 and 85 dB SPL). The outcome suggests that hearing aid fitting procedures aiming to equalize loudness of speech bands should prescribe less low-frequency gain than procedures aiming to normalize loudness of speech bands. A significant interaction was found between bandwidth and input level for the high-frequency bands.

  1. A sophisticated, multi-channel data acquisition and processing system for high frequency noise research

    NASA Technical Reports Server (NTRS)

    Hall, David G.; Bridges, James

    1992-01-01

    A sophisticated, multi-channel computerized data acquisition and processing system was developed at the NASA LeRC for use in noise experiments. This technology, which is available for transfer to industry, provides a convenient, cost-effective alternative to analog tape recording for high frequency acoustic measurements. This system provides 32-channel acquisition of microphone signals with an analysis bandwidth up to 100 kHz per channel. Cost was minimized through the use of off-the-shelf components. Requirements to allow for future expansion were met by choosing equipment which adheres to established industry standards for hardware and software. Data processing capabilities include narrow band and 1/3 octave spectral analysis, compensation for microphone frequency response/directivity, and correction of acoustic data to standard day conditions. The system was used successfully in a major wind tunnel test program at NASA LeRC to acquire and analyze jet noise data in support of the High Speed Civil Transport (HSCT) program.

  2. High bandwidth optical mount

    DOEpatents

    Bender, D.A.; Kuklo, T.

    1994-11-08

    An optical mount, which directs a laser beam to a point by controlling the position of a light-transmitting optic, is stiffened so that a lowest resonant frequency of the mount is approximately one kilohertz. The optical mount, which is cylindrically-shaped, positions the optic by individually moving a plurality of carriages which are positioned longitudinally within a sidewall of the mount. The optical mount is stiffened by allowing each carriage, which is attached to the optic, to move only in a direction which is substantially parallel to a center axis of the optic. The carriage is limited to an axial movement by flexures or linear bearings which connect the carriage to the mount. The carriage is moved by a piezoelectric transducer. By limiting the carriage to axial movement, the optic can be kinematically clamped to a carriage. 5 figs.

  3. High bandwidth optical mount

    DOEpatents

    Bender, Donald A.; Kuklo, Thomas

    1994-01-01

    An optical mount, which directs a laser beam to a point by controlling the position of a light-transmitting optic, is stiffened so that a lowest resonant frequency of the mount is approximately one kilohertz. The optical mount, which is cylindrically-shaped, positions the optic by individually moving a plurality of carriages which are positioned longitudinally within a sidewall of the mount. The optical mount is stiffened by allowing each carriage, which is attached to the optic, to move only in a direction which is substantially parallel to a center axis of the optic. The carriage is limited to an axial movement by flexures or linear bearings which connect the carriage to the mount. The carriage is moved by a piezoelectric transducer. By limiting the carriage to axial movement, the optic can be kinematically clamped to a carriage.

  4. High-bandwidth, high-sampling-rate, low-noise, two-probe transient photovoltage measuring system

    SciTech Connect

    Chen, Xiaoqing; Wu, Bo

    2015-01-15

    In this article, we present a two-probe configuration for measuring transient photovoltage (TPV) signals from photo-electronic semiconductor devices. Unlike in a conventional one-probe system, the two electrodes of the devices under test in this study are both monitored in our new measuring system, giving rise to a significantly enhanced signal-to-noise ratio. Tentative experimental data ob tained from N, N′-Di(1-naphthyl)-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine-based organic semiconductor devices show that the bandwidth and the sampling rate of the system reach 1.5 GHz and 50 GS/s, respectively, without degradation of the noise level. In addition, the study of TPV signals on each individual electrode is allowed. The TPV values measured by the two individual probes are not identically equal to half of the differential TPV and will not cancel each other out as expected. This abnormal phenomenon is due to the photoelectric response of the photo-electronic material. This novel two-probe TPV measuring technique and abnormal TPV behavior might be useful for studying more dynamic processes in photo-electronic semiconductors.

  5. Reproducible high-resolution multispectral image acquisition in dermatology

    NASA Astrophysics Data System (ADS)

    Duliu, Alexandru; Gardiazabal, José; Lasser, Tobias; Navab, Nassir

    2015-07-01

    Multispectral image acquisitions are increasingly popular in dermatology, due to their improved spectral resolution which enables better tissue discrimination. Most applications however focus on restricted regions of interest, imaging only small lesions. In this work we present and discuss an imaging framework for high-resolution multispectral imaging on large regions of interest.

  6. The ATLAS Data Acquisition and High Level Trigger system

    NASA Astrophysics Data System (ADS)

    The ATLAS TDAQ Collaboration

    2016-06-01

    This paper describes the data acquisition and high level trigger system of the ATLAS experiment at the Large Hadron Collider at CERN, as deployed during Run 1. Data flow as well as control, configuration and monitoring aspects are addressed. An overview of the functionality of the system and of its performance is presented and design choices are discussed.

  7. Short-Term Word-Learning Rate in Children with Normal Hearing and Children with Hearing Loss in Limited and Extended High-Frequency Bandwidths

    ERIC Educational Resources Information Center

    Pittman, Andrea L.

    2008-01-01

    Purpose: This study examined children's word learning in limited and extended high-frequency bandwidth conditions. These conditions represent typical listening environments for children with hearing loss (HL) and children with normal hearing (NH), respectively. Method: Thirty-six children with NH and 14 children with moderate-to-severe HL served…

  8. Remote, Real-time Investigations of Extreme Environments Using High Power and Bandwidth Cabled Observatories: The OOI Regional Scale Nodes

    NASA Astrophysics Data System (ADS)

    Kelley, D. S.; Delaney, J. R.

    2012-12-01

    Methane hydrate deposits and hydrothermal vents are two of the most extreme environments on Earth. Seismic events and flow of gases from the seafloor support and modulate novel microbial communities within these systems. Although studied intensely for several decades, significant questions remain about the flux of heat, volatiles and microbial material from the subsurface to the hydrosphere in these dynamic environments. Quantification of microbial communities, their structure and abundances, and metabolic activities is in an infant state. To better understand these systems, the National Science Foundation's Ocean Observatory Initiative has installed high power (8 kW), high bandwidth (10 Gb/s) nodes on the seafloor that provide access to active methane seeps at Southern Hydrate Ridge, and at the most magmatically robust volcano on the Juan de Fuca Ridge - Axial Seamount. The real-time interactive capabilities of the cabled observatory are critical to studying gas-hydrate systems because many of the key processes occur over short time scales. Events such as bubble plume formation, the creation of collapse zones, and increased seepage in response to earthquakes require adaptive response and sampling capabilities. To meet these challenges a suite of instruments will be connected to the cable in 2013. These sensors include full resolution sampling by upward-looking sonars, fluid and gas chemical characterization by mass spectrometers and osmo samplers, long-term duration collection of seep imagery from cameras, and in situ manipulation of chemical sensors coupled with flow meters. In concert, this instrument suite will provide quantification of transient and more stable chemical fluxes. Similarly, at Axial Seamount the high bandwidth and high power fiber optic cables will be used to communicate with and power a diverse array of sensors at the summit of the volcano. Real-time high definition video will provide unprecedented views of macrofaunal and microbial communities

  9. High Quality Acquisition of Surface Electromyography - Conditioning Circuit Design

    NASA Astrophysics Data System (ADS)

    Shobaki, Mohammed M.; Malik, Noreha Abdul; Khan, Sheroz; Nurashikin, Anis; Haider, Samnan; Larbani, Sofiane; Arshad, Atika; Tasnim, Rumana

    2013-12-01

    The acquisition of Surface Electromyography (SEMG) signals is used for many applications including the diagnosis of neuromuscular diseases, and prosthesis control. The diagnostic quality of the SEMG signal is highly dependent on the conditioning circuit of the SEMG acquisition system. This paper presents the design of an SEMG conditioning circuit that can guarantee to collect high quality signal with high SNR such that it is immune to environmental noise. The conditioning circuit consists of four stages; consisting of an instrumentation amplifier that is used with a gain of around 250; 4th order band pass filter in the 20-500Hz frequency range as the two initial stages. The third stage is an amplifier with adjustable gain using a variable resistance; the gain could be changed from 1000 to 50000. In the final stage the signal is translated to meet the input requirements of data acquisition device or the ADC. Acquisition of accurate signals allows it to be analyzed for extracting the required characteristic features for medical and clinical applications. According to the experimental results, the value of SNR for collected signal is 52.4 dB which is higher than the commercial system, the power spectrum density (PSD) graph is also presented and it shows that the filter has eliminated the noise below 20 Hz.

  10. A High Performance Virtualized Seismic Data Acquisition System

    NASA Astrophysics Data System (ADS)

    Davis, G. A.; Eakins, J. A.; Reyes, J. C.; Franke, M.; Sánchez, R. F.; Cortes Muñoz, P.; Busby, R. W.; Vernon, F.; Barrientos, S. E.

    2014-12-01

    As part of a collaborative effort with the Incorporated Research Institutions for Seismology, a virtualized seismic data acquisition and processing system was recently installed at the Centro Sismológical Nacional (CSN) at the Universidad de Chile for use as part of their early warning system. Using lessons learned from the Earthscope Transportable Array project, the design of this system consists of dedicated acquisition, processing and data distribution nodes hosted on a high availability hypervisor cluster. Data is exchanged with the IRIS Data Management Center and the existing processing infrastructure at the CSN. The processing nodes are backed by 20 TB of hybrid Solid State Disk (SSD) and spinning disk storage with automatic tiering of data between the disks. As part of the installation, best practices for station metadata maintenance were discussed and applied to the existing IRIS sponsored stations, as well as over 30 new stations being added to the early warning network. Four virtual machines (VM) were configured with distinctive tasks. Two VMs are dedicated to data acquisition, one to the real-time data processing, and one as relay between data acquisition and processing systems with services for the existing earthquake revision and dissemination infrastructure. The first acquisition system connects directly to Basalt dataloggers and Q330 digitizers, managing them, and acquiring seismic data as well as state-of-health (SOH) information. As newly deployed stations become available (beyond the existing 30), this VM is configured to acquire data from them and incorporate the additonal data. The second acquisition system imports the legacy network of CSN and data streams provided by other data centers. The processing system is connected to the production and archive databases. The relay system merges all incoming data streams and obtains the processing results. Data and processing packets are available for subsequent review and dissemination by the CSN. Such

  11. Application of a modified complementary filtering technique for increased aircraft control system frequency bandwidth in high vibration environment

    NASA Technical Reports Server (NTRS)

    Garren, J. F., Jr.; Niessen, F. R.; Abbott, T. S.; Yenni, K. R.

    1977-01-01

    A modified complementary filtering technique for estimating aircraft roll rate was developed and flown in a research helicopter to determine whether higher gains could be achieved. Use of this technique did, in fact, permit a substantial increase in system frequency bandwidth because, in comparison with first-order filtering, it reduced both noise amplification and control limit-cycle tendencies.

  12. Vertical-bandwidth-limited digital holography.

    PubMed

    Liu, Jung-Ping; Lee, Chieh-Cheng; Lo, Ying-Hau; Luo, Dao-Zheng

    2012-07-01

    Optical scanning holography (OSH) is a promising technique to acquire a big-size digital hologram. However, the acquisition speed is limited by the mechanical scanner. In this Letter we apply the OSH in conjunction with an anisotropic low-pass filtering pupil to acquire vertical-bandwidth-limited (VBL) holograms. The size and the acquisition time of the VBL hologram can be reduced by one order of magnitude while the horizontal resolution remains the same as the conventional scanning hologram. The VBL hologram can be coded as an off-axis hologram without any postfiltering. Meanwhile, the full horizontal bandwidth of the displaying device can be capitalized.

  13. A data acquisition and control system for high-speed gamma-ray tomography

    NASA Astrophysics Data System (ADS)

    Hjertaker, B. T.; Maad, R.; Schuster, E.; Almås, O. A.; Johansen, G. A.

    2008-09-01

    A data acquisition and control system (DACS) for high-speed gamma-ray tomography based on the USB (Universal Serial Bus) and Ethernet communication protocols has been designed and implemented. The high-speed gamma-ray tomograph comprises five 500 mCi 241Am gamma-ray sources, each at a principal energy of 59.5 keV, which corresponds to five detector modules, each consisting of 17 CdZnTe detectors. The DACS design is based on Microchip's PIC18F4550 and PIC18F4620 microcontrollers, which facilitates an USB 2.0 interface protocol and an Ethernet (IEEE 802.3) interface protocol, respectively. By implementing the USB- and Ethernet-based DACS, a sufficiently high data acquisition rate is obtained and no dedicated hardware installation is required for the data acquisition computer, assuming that it is already equipped with a standard USB and/or Ethernet port. The API (Application Programming Interface) for the DACS is founded on the National Instrument's LabVIEW® graphical development tool, which provides a simple and robust foundation for further application software developments for the tomograph. The data acquisition interval, i.e. the integration time, of the high-speed gamma-ray tomograph is user selectable and is a function of the statistical measurement accuracy required for the specific application. The bandwidth of the DACS is 85 kBytes s-1 for the USB communication protocol and 28 kBytes s-1 for the Ethernet protocol. When using the iterative least square technique reconstruction algorithm with a 1 ms integration time, the USB-based DACS provides an online image update rate of 38 Hz, i.e. 38 frames per second, whereas 31 Hz for the Ethernet-based DACS. The off-line image update rate (storage to disk) for the USB-based DACS is 278 Hz using a 1 ms integration time. Initial characterization of the high-speed gamma-ray tomograph using the DACS on polypropylene phantoms is presented in the paper.

  14. ABB: active bandwidth broker

    NASA Astrophysics Data System (ADS)

    Wong, Kason; Law, Eddie

    2001-07-01

    In this paper, we shall discuss a novel design on the policy-based management for the Internet. This design deploys the concept of active networking. As opposed to the traditional network design, active network empowers network node with the ability to manipulate data and program code in packets, and configure the network properties according to the needs of different applications. The policy-based management can control network routers in order to realize end-to-end Quality of Service (QoS), such as differentiated and integrated services, across the Internet. For the moment, the Internet Engineering Task Force (IETF) has defined the framework of the policy-based management. It employs a simple client/server model that uses Common Open Policy Service (COPS) protocol to facilitate policy management and control. Our design of Active Bandwidth Broker (ABB) belongs to an active application. Our goals are to distribute centralized workload of the policy-based management over multiple active nodes in the active networks, introduce mobility of the bandwidth brokers, and allows load sharing to the policy-based management. This results a network-wide intelligent, highly available, and consistent QoS control that allows performance protection for voice, video and Internet business application while reducing costs for growing networks.

  15. Brewster-angled chirped mirrors for high-fidelity dispersion compensation and bandwidths exceeding one optical octave

    NASA Astrophysics Data System (ADS)

    Steinmeyer, G.

    2003-09-01

    A novel design approach for dispersion-compensating chirped mirrors with greater-than-octave bandwidth is proposed. The commonly encountered problem of dispersion ripple is overcome by impedance matching via Brewster incidence in respect to the top-layer coating material. This approach totally suppresses undesired reflections off the interface to the ambient medium without any need for complicated matching sections. It is shown that Brewster-angled chirped mirrors can deliver ultrabroadband dispersion compensation over a much wider bandwidth than conventional doublechirped mirrors and without the mechanical complexity of back-deposition approaches. Due to their relatively simple structure, the sensitivity of the dispersion of the Brewster-angled designs towards growth errors is greatly reduced. Therefore, this new generation of chirped mirrors appears ideal for compression of continuum pulses with a potential of pulse durations in the single-cycle regime.

  16. A research of a high precision multichannel data acquisition system

    NASA Astrophysics Data System (ADS)

    Zhong, Ling-na; Tang, Xiao-ping; Yan, Wei

    2013-08-01

    The output signals of the focusing system in lithography are analog. To convert the analog signals into digital ones which are more flexible and stable to process, a desirable data acquisition system is required. The resolution of data acquisition, to some extent, affects the accuracy of focusing. In this article, we first compared performance between the various kinds of analog-to-digital converters (ADC) available on the market at the moment. Combined with the specific requirements (sampling frequency, converting accuracy, numbers of channels etc) and the characteristics (polarization, amplitude range etc) of the analog signals, the model of the ADC to be used as the core chip in our hardware design was determined. On this basis, we chose other chips needed in the hardware circuit that would well match with ADC, then the overall hardware design was obtained. Validation of our data acquisition system was verified through experiments and it can be demonstrated that the system can effectively realize the high resolution conversion of the multi-channel analog signals and give the accurate focusing information in lithography.

  17. Application of DSP Blackfin in data acquisition of high speed

    NASA Astrophysics Data System (ADS)

    Tang, Chao

    2015-12-01

    In the traditional digital collection, the use of FIFO and MCU is usually used. Traditional data acquisition systems are expensive and slow, When the input is a fast changing signal, the output will have a large distortion, which makes the whole system performance degradation, and not suitable for large amounts of data. In this paper, a new method of high speed data acquisition based on Blackfin DSP is presented, The analog signal is processed by the signal processing circuit, so that the amplitude of the signal is limited to the input range of the A/D converter. The whole collection system is determined by the data acquisition and control circuit. In order to further improve the speed of data transmission, DSP Blackfin uses advanced DMA technology. In the algorithm, the system is mainly used in the same sampling points for the average value of the method. Experimental results show, Using the traditional system, it will lose a lot of details, the destruction of the integrity of the signal. Using this system can well reconstruct the analog signal input, Especially in the large amount of data, it shows the incomparable advantages.

  18. Isolated data acquisition system for high voltage applications

    SciTech Connect

    Waitz, A.; Donaldson, A.

    1985-06-01

    This report describes the design and operation of a microcomputer controlled system for acquisition of both analog and binary data within the high voltage stages of a linac modulator. The system is comprised of a microprocessor Controller which communicates with the remote data Acquisition circuits via an optical bus. The bus, which uses a 1 MHz Manchester II format, is configured as a loop, starting at the Controller, daisy-chaining the remote cards and terminating back at the Controller. Upon receiving a linac timing pulse, the Controller sends addressed commands to the individual remote cards and receives data back. It then passes this data to the linac control system through a Multibus connection. Each remote circuit can return 16 binary sense and 7 (12 bit) analog parameters within 270 us. This speed is possible because of a pipelined design where one word is transmitted while another is being converted. A data conversion cycle is initiated when a remote data acquisition card receives the proper command and address from the controller.

  19. Novel high-gain, improved-bandwidth, finned-ladder V-band Traveling-Wave Tube slow-wave circuit design

    NASA Technical Reports Server (NTRS)

    Kory, Carol L.; Wilson, Jeffrey D.

    1994-01-01

    The V-band frequency range of 59-64 GHz is a region of the millimeter-wave spectrum that has been designated for inter-satellite communications. As a first effort to develop a high-efficiency V-band Traveling-Wave Tube (TWT), variations on a ring-plane slow-wave circuit were computationally investigated to develop an alternative to the more conventional ferruled coupled-cavity circuit. The ring-plane circuit was chosen because of its high interaction impedance, large beam aperture, and excellent thermal dissipation properties. Despite these advantages, however, low bandwidth and high voltage requirements have, until now, prevented its acceptance outside the laboratory. In this paper, the three-dimensional electrodynamic simulation code MAFIA (solution of MAxwell's Equation by the Finite-Integration-Algorithm) is used to investigate methods of increasing the bandwidth and lowering the operating voltage of the ring-plane circuit. Calculations of frequency-phase dispersion, beam on-axis interaction impedance, attenuation and small-signal gain per wavelength were performed for various geometric variations and loading distributions of the ring-plane TWT slow-wave circuit. Based on the results of the variations, a circuit termed the finned-ladder TWT slow-wave circuit was designed and is compared here to the scaled prototype ring-plane and a conventional ferruled coupled-cavity TWT circuit over the V-band frequency range. The simulation results indicate that this circuit has a much higher gain, significantly wider bandwidth, and a much lower voltage requirement than the scaled ring-plane prototype circuit, while retaining its excellent thermal dissipation properties. The finned-ladder circuit has a much larger small-signal gain per wavelength than the ferruled coupled-cavity circuit, but with a moderate sacrifice in bandwidth.

  20. Clock signal requirement for high-frequency, high dynamic range acquisition systems

    SciTech Connect

    Viscor, Ivo; Halamek, Josef; Villa, Marco

    2005-11-15

    Analog-to-digital converters (ADC's) are increasingly replacing mixers in frequency conversion schemes. To achieve superior performances, in terms of bandwidth and dynamic range, a nearly ideal ADC clock is needed, with a spectral purity higher than the reference signal of the classical mixing scheme. These requirements of spectral purity for the ADC clock are discussed by analyzing in detail the nonuniform sampling process and by characterizing an actual acquisition system. The effect of clock phase imperfections on the output is proportional to the input frequency over sampling frequency ratio. Moreover, at the output we may have a multiple folding of the phase jitter spectrum. These effects are illustrated by three sets of measurements performed using our system: transfer of spurious clock components, aliasing of these components, and transfer of clock phase noise.

  1. Bandwidth requirements for fine resolution squinted SAR

    SciTech Connect

    DOERRY,ARMIN W.

    2000-03-01

    The conventional rule-of-thumb for Synthetic Aperture Radar is that an RF bandwidth of c/(2{rho}{sub r}) is required to image a scene at the desired slant-range resolution {rho}{sub r}, and perhaps a little more to account for window functions and sidelobe control. This formulation is based on the notion that the total bandwidth required is the same bandwidth that is required for a single pulse. What is neglected is that efficient processing of an entire synthetic aperture of pulses will often require different frequency content for each of the different pulses that makeup a synthetic aperture. Consequently, the total RF bandwidth required of a Synthetic Aperture Radar may then be substantially wider than the bandwidth of any single pulse. The actual RF bandwidth required depends strongly on flight geometry, owing to the desire for a radar to maintain a constant projection of the Fourier space collection surface onto the {omega}{sub y} axis. Long apertures required for fine azimuth resolution, and severe squint angles with steep depression angles may require total RF bandwidths well beyond the minimum bandwidth required of any single transmitted pulse, perhaps even by a factor of two or more. Accounting for this is crucial to designing efficient versatile high-performance imaging radars. This paper addresses how a data set conducive to efficient processing might increase the total RF bandwidth, and presents examples of how a fixed RF bandwidth might then limit SAR geometries.

  2. Rapid brain MRI acquisition techniques at ultra-high fields.

    PubMed

    Setsompop, Kawin; Feinberg, David A; Polimeni, Jonathan R

    2016-09-01

    Ultra-high-field MRI provides large increases in signal-to-noise ratio (SNR) as well as enhancement of several contrast mechanisms in both structural and functional imaging. Combined, these gains result in a substantial boost in contrast-to-noise ratio that can be exploited for higher-spatial-resolution imaging to extract finer-scale information about the brain. With increased spatial resolution, however, there is a concurrent increased image-encoding burden that can cause unacceptably long scan times for structural imaging and slow temporal sampling of the hemodynamic response in functional MRI - particularly when whole-brain imaging is desired. To address this issue, new directions of imaging technology development - such as the move from conventional 2D slice-by-slice imaging to more efficient simultaneous multislice (SMS) or multiband imaging (which can be viewed as "pseudo-3D" encoding) as well as full 3D imaging - have provided dramatic improvements in acquisition speed. Such imaging paradigms provide higher SNR efficiency as well as improved encoding efficiency. Moreover, SMS and 3D imaging can make better use of coil sensitivity information in multichannel receiver arrays used for parallel imaging acquisitions through controlled aliasing in multiple spatial directions. This has enabled unprecedented acceleration factors of an order of magnitude or higher in these imaging acquisition schemes, with low image artifact levels and high SNR. Here we review the latest developments of SMS and 3D imaging methods and related technologies at ultra-high field for rapid high-resolution functional and structural imaging of the brain. Copyright © 2016 John Wiley & Sons, Ltd.

  3. Acquisition of smoking refusal skills in junior high school students.

    PubMed

    Katz, R C; Robisch, C M; Telch, M J

    1989-01-01

    This study examined the effects of a smoking prevention program on the acquisition of refusal skills among junior high school students. Two conditions were compared: one in which the subjects participated in a videotaped training program on resisting pressures to smoke, and the other an untreated control group. As predicted, the results showed significant improvement in the skill training group, while the untreated controls showed no change relative to their pretest performance. These findings suggest that smoking prevention programs which focus on resisting social pressures can enhance the young person's ability to say "no" to smoking. PMID:2728956

  4. Characterization of Nyquist ghost in EPI-fMRI acquisition sequences implemented on two clinical 1.5 T MR scanner systems: effect of readout bandwidth and echo spacing.

    PubMed

    Giannelli, Marco; Diciotti, Stefano; Tessa, Carlo; Mascalchi, Mario

    2010-07-12

    In EPI-fMRI acquisitions, various readout bandwidth (BW) values are used as a function of gradients' characteristics of the MR scanner system. Echo spacing (ES) is another fundamental parameter of EPI-fMRI sequences, but the employed ES value is not usually reported in fMRI studies. Nyquist ghost is a typical EPI artifact that can degrade the overall quality of fMRI time series. In this work, the authors assessed the basic effect of BW and ES for two clinical 1.5 T MR scanner systems (scanner-A, scanner-B) on Nyquist ghost of gradient-echo EPI-fMRI sequences. BW range was: scanner-A, 1953-3906 Hz/pixel; scanner-B, 1220-2894 Hz/pixel. ES range was: scanner-A, scanner-B: 0.75-1.33 ms. The ghost-to-signal ratio of time series acquisition (GSRts) and drift of ghost-to-signal ratio (DRGSR) were measured in a water phantom. For both scanner-A (93% of variation) and scanner-B (102% of variation) the mean GSRts significantly increased with increasing BW. GSRts values of scanner-A did not significantly depended on ES. On the other hand, GSRts values of scanner-B significantly varied with ES, showing a downward trend (81% of variation) with increasing ES. In addition, a GSRts spike point at ES = 1.05 ms indicating a potential resonant effect was revealed. For both scanners, no significant effect of ES on DRGSR was revealed. DRGSR values of scanner-B did not significantly vary with BW, whereas DRGSR values of scanner-A significantly depended on BW showing an upward trend from negative to positive values with increasing BW. GSRts and DRGSR can significantly vary with BW and ES, and the specific pattern of variation may depend on gradients performances, EPI sequence calibrations and functional design of radiofrequency coil. Thus, each MR scanner system should be separately characterized. In general, the employment of low BW values seems to reduce the intensity and temporal variation of Nyquist ghost in EPI-fMRI time series. On the other hand, the use of minimum ES value might

  5. Optimisation of acquisition time in bioluminescence imaging

    NASA Astrophysics Data System (ADS)

    Taylor, Shelley L.; Mason, Suzannah K. G.; Glinton, Sophie; Cobbold, Mark; Styles, Iain B.; Dehghani, Hamid

    2015-03-01

    Decreasing the acquisition time in bioluminescence imaging (BLI) and bioluminescence tomography (BLT) will enable animals to be imaged within the window of stable emission of the bioluminescent source, a higher imaging throughput and minimisation of the time which an animal is anaesthetised. This work investigates, through simulation using a heterogeneous mouse model, two methods of decreasing acquisition time: 1. Imaging at fewer wavelengths (a reduction from five to three); and 2. Increasing the bandwidth of filters used for imaging. The results indicate that both methods are viable ways of decreasing the acquisition time without a loss in quantitative accuracy. Importantly, when choosing imaging wavelengths, the spectral attenuation of tissue and emission spectrum of the source must be considered, in order to choose wavelengths at which a high signal can be achieved. Additionally, when increasing the bandwidth of the filters used for imaging, the bandwidth must be accounted for in the reconstruction algorithm.

  6. Chemical Industry Bandwidth Study

    SciTech Connect

    none,

    2006-12-01

    The Chemical Bandwidth Study provides a snapshot of potentially recoverable energy losses during chemical manufacturing. The advantage of this study is the use of "exergy" analysis as a tool for pinpointing inefficiencies.

  7. FASTBUS Readout Controller card for high speed data acquisition

    SciTech Connect

    Zimmermann, S. Rio Grande do Sul Univ., Porto Alegre, RS . Dept. of Electrical Engineering); Areti, V.H.; Foster, G.W.; Joshi, U.; Treptow, K. )

    1991-10-01

    This article describes a FASTBUS Readout Controller (FRC) for high speed data acquisition in FASTBUS based systems. The controller has two main interfaces: to FASTBUS and to a Readout Port. The FASTBUS interface performs FASTBUS master and slave operations at a maximum transfer rate exceeding 40 MBytes/s. The Readout Port can be adapted for a variety of protocols. Currently, it will be interfaced to a VME bus based processor with a VSB port. The on-board LR33000 embedded processor controls the readout, executing a list of operations download into its memory. It scans the FASTBUS modules and stores the data in a triple port DRAM (TPDRAM), through one of the Serial Access Memory (SAM) ports of the (TPDRAM). Later, it transfers this data to the readout port using the other SAM. The FRC also supports serial communication via RS232 and Ethernet interfaces. This device is intended for use in the data acquisition system at the Collider Detector at Fermilab. 5 refs., 3 figs.

  8. Glass Industry Bandwidth Analysis

    SciTech Connect

    Rue, David M.

    2006-07-01

    This is a study on energy use and potential savings, or "bandwidth" study, for several glassmaking processes. Intended to provide a realistic estimate of the potential amount of energy that can be saved in an industrial process, the "bandwidth" refers to the difference between the amount of energy that would be consumed in a process using commercially available technology versus the minimum amount of energy needed to achieve those same results.

  9. Industrial Glass Bandwidth Analysis

    SciTech Connect

    Rue, David M.; Servaites, James; Wolf, Warren

    2007-08-01

    This is a study on energy use and potential savings, or "bandwidth" study, for several glassmaking processes. Intended to provide a realistic estimate of the potential amount of energy that can be saved in an industrial process, the "bandwidth" refers to the difference between the amount of energy that would be consumed in a process using commercially available technology versus the minimum amount of energy needed to achieve those same results.

  10. Control and data acquisition systems for high field superconducting wigglers

    NASA Astrophysics Data System (ADS)

    Batrakov, A.; Ilyin, I.; Karpov, G.; Kozak, V.; Kuzin, M.; Kuper, E.; Mamkin, V.; Mezentsev, N.; Repkov, V.; Selivanov, A.; Shkaruba, V.

    2001-07-01

    This paper describes the control and DAQ system of superconducting wigglers with magnetic field range up to 10.3 T. The first version of the system controls a 7 T superconducting wiggler prepared for installation at Bessy-II (Germany). The second one controls a 10 T wiggler which is under testing now at the SPring-8 site (Japan). Both systems are based on VME apparatus. The set of specialized VME modules is elaborated to arrange wiggler power supply control, full time wiggler monitoring, and magnetic field high accuracy measurement and field stabilization. The software for the control of the wigglers is written in C language for VxWorks operation system for a Motorola-162 VME controller. The task initialization, stops and acquisition of the data can be done from the nearest personal computer (FTP host for VME), or from the remote system as well.

  11. A high-speed transputer-based data acquisition system

    NASA Astrophysics Data System (ADS)

    Loureiro, C. F. M.; Santos, J. M. G. B.; Simões, J. B.; Correia, C. M. B. A.; Zilker, M.

    1996-01-01

    A 250 MHz 8-bit transputer-based data acquisition VME bus module is described. This module has been designed as the acquisition node of a transputer-based real-time processing and data reduction system for the reflectometry diagnostic in the ASDEX Upgrade tokamak experiment. The architecture of the board is detailed, emphasizing the advantages of using recently delivered devices, like fast synchronous FIFOs, in a mixed ECL/TTL data acquisition architecture. It is shown that the implemented architecture leads naturally to the implementation of hardware triggers that allow the acquisition channels to operate as stand-alone modules in a self-triggered, self-timed, data acquisition mode. The advantages of using transputers as local control and processing units are discussed. The use of the board in the reflectometry diagnostic and the general processing goals of the system are presented together with data characterizing the performance of the acquisition channels.

  12. A high speed buffer for LV data acquisition

    NASA Technical Reports Server (NTRS)

    Cavone, Angelo A.; Sterlina, Patrick S.; Clemmons, James I., Jr.; Meyers, James F.

    1987-01-01

    The laser velocimeter (autocovariance) buffer interface is a data acquisition subsystem designed specifically for the acquisition of data from a laser velocimeter. The subsystem acquires data from up to six laser velocimeter components in parallel, measures the times between successive data points for each of the components, establishes and maintains a coincident condition between any two or three components, and acquires data from other instrumentation systems simultaneously with the laser velocimeter data points. The subsystem is designed to control the entire data acquisition process based on initial setup parameters obtained from a host computer and to be independent of the computer during the acquisition. On completion of the acquisition cycle, the interface transfers the contents of its memory to the host under direction of the host via a single 16-bit parallel DMA channel.

  13. Broad Bandwidth Telecommunications Systems.

    ERIC Educational Resources Information Center

    Sodolski, John

    Broad bandwidth transmission systems have been around for years. They include microwave, assorted cable systems, and recently, satellites. With the exception of some privately owned systems, broadband services have been furnished by the common carriers. Recently, a new element has been added--Cable Antenna Television (CATV) distribution systems.…

  14. Source parameters and effects of bandwidth and local geology on high- frequency ground motions observed for aftershocks of the northeastern Ohio earthquake of 31 January 1986

    USGS Publications Warehouse

    Glassmoyer, G.; Borcherdt, R.D.

    1990-01-01

    A 10-station array (GEOS) yielded recordings of exceptional bandwidth (400 sps) and resolution (up to 96 dB) for the aftershocks of the moderate (mb???4.9) earthquake that occurred on 31 January 1986 near Painesville, Ohio. Nine aftershocks were recorded with seismic moments ranging between 9 ?? 1016 and 3 ?? 1019 dyne-cm (MW: 0.6 to 2.3). The aftershock recordings at a site underlain by ???8m of lakeshore sediments show significant levels of high-frequency soil amplification of vertical motion at frequencies near 8, 20 and 70 Hz. Viscoelastic models for P and SV waves incident at the base of the sediments yield estimates of vertical P-wave response consistent with the observed high-frequency site resonances, but suggest additional detailed shear-wave logs are needed to account for observed S-wave response. -from Authors

  15. A New Sensorless Vector Control Method Using High Order Filters with Speed-Varying Bandwidth for Permanent-Magnet Synchronous Motors

    NASA Astrophysics Data System (ADS)

    Shinnaka, Shinji

    This paper proposes a new rotor phase estimation method for sensorless drive of permanent-magnet synchronous motors (PMSMs), which uses motor-driving stator voltage and current information for estimation. The proposed estimation method utilizes two high order low-pass filters that can change their bandwidth according to speed estimate. The high order filters have a potential to attenuate sufficiently harmonics contaminating the stator voltage and current and to produce almost-pure-sinusoidal rotor flux estimate consisting of fundamental component only. Such a sinusoidal rotor flux estimate allows high accurate estimation of rotor phase even at very low speed. In order to separate the fundamental component of the rotor flux estimate from its harmonics with no phase lag/lead in variable-speed environments, the proposed low-pass filters have a function to change its bandwidth adaptively to rotor speed. The sensorless drive system using the proposed phase estimation method can show such high performance that 1) it can startup PMSMs from standstill under the rated load; 2) it can drive PMSMs stably even at very low speed such as 1/60 of the rated speed under the rated motoring/regenerating load; 3) it can drive PMSMs accompanied with a load of over 50 times large inertia. The proposed estimation method is simple and easily installed into sensorless drive systems. This paper presents the new estimation method in detail and show how it is installed into the drive systems by using a concrete example. The usefulness of the method and the performance of the drive system are examined and confirmed through extensive experiments.

  16. Method and apparatus for high speed data acquisition and processing

    DOEpatents

    Ferron, John R.

    1997-01-01

    A method and apparatus for high speed digital data acquisition. The apparatus includes one or more multiplexers for receiving multiple channels of digital data at a low data rate and asserting a multiplexed data stream at a high data rate, and one or more FIFO memories for receiving data from the multiplexers and asserting the data to a real time processor. Preferably, the invention includes two multiplexers, two FIFO memories, and a 64-bit bus connecting the FIFO memories with the processor. Each multiplexer receives four channels of 14-bit digital data at a rate of up to 5 MHz per channel, and outputs a data stream to one of the FIFO memories at a rate of 20 MHz. The FIFO memories assert output data in parallel to the 64-bit bus, thus transferring 14-bit data values to the processor at a combined rate of 40 MHz. The real time processor is preferably a floating-point processor which processes 32-bit floating-point words. A set of mask bits is prestored in each 32-bit storage location of the processor memory into which a 14-bit data value is to be written. After data transfer from the FIFO memories, mask bits are concatenated with each stored 14-bit data value to define a valid 32-bit floating-point word. Preferably, a user can select any of several modes for starting and stopping direct memory transfers of data from the FIFO memories to memory within the real time processor, by setting the content of a control and status register.

  17. Method and apparatus for high speed data acquisition and processing

    DOEpatents

    Ferron, J.R.

    1997-02-11

    A method and apparatus are disclosed for high speed digital data acquisition. The apparatus includes one or more multiplexers for receiving multiple channels of digital data at a low data rate and asserting a multiplexed data stream at a high data rate, and one or more FIFO memories for receiving data from the multiplexers and asserting the data to a real time processor. Preferably, the invention includes two multiplexers, two FIFO memories, and a 64-bit bus connecting the FIFO memories with the processor. Each multiplexer receives four channels of 14-bit digital data at a rate of up to 5 MHz per channel, and outputs a data stream to one of the FIFO memories at a rate of 20 MHz. The FIFO memories assert output data in parallel to the 64-bit bus, thus transferring 14-bit data values to the processor at a combined rate of 40 MHz. The real time processor is preferably a floating-point processor which processes 32-bit floating-point words. A set of mask bits is prestored in each 32-bit storage location of the processor memory into which a 14-bit data value is to be written. After data transfer from the FIFO memories, mask bits are concatenated with each stored 14-bit data value to define a valid 32-bit floating-point word. Preferably, a user can select any of several modes for starting and stopping direct memory transfers of data from the FIFO memories to memory within the real time processor, by setting the content of a control and status register. 15 figs.

  18. Low Group Delay Dispersion Optical Coating for Broad Bandwidth High Reflection at 45° Incidence, P Polarization of Femtosecond Pulses with 900 nm Center Wavelength

    DOE PAGES

    Bellum, John C.; Field, Ella S.; Winstone, Trevor B.; Kletecka, Damon E.

    2016-03-01

    We describe an optical coating design suitable for broad bandwidth high reflection (BBHR) at 45° angle of incidence (AOI), P polarization (Ppol) of femtosecond (fs) laser pulses whose wavelengths range from 800 to 1000 nm. The design process is guided by quarter-wave HR coating properties. Our design must afford low group delay dispersion (GDD) for reflected light over the broad, 200 nm bandwidth in order to minimize temporal broadening of the fs pulses due to dispersive alteration of relative phases between their frequency components. The design should also be favorable to high laser-induced damage threshold (LIDT). We base the coatingmore » on TiO2/SiO2 layer pairs produced by means of e-beam evaporation with ion-assisted deposition, and use OptiLayer Thin Film Software to explore designs starting with TiO2/SiO2 layers having thicknesses in a reverse chirped arrangement. This approach led to a design with R > 99% from 800 to 1000 nm and GDD < 20 fs2 from 843 to 949 nm (45° AOI, Ppol). The design’s GDD behaves in a smooth way, suitable for GDD compensation techniques, and its electric field intensities show promise for high LIDTs. Reflectivity and GDD measurements for the initial test coating indicate good performance of the BBHR design. Subsequent coating runs with improved process calibration produced two coatings whose HR bands satisfactorily meet the design goals. Lastly, for the sake of completeness, we summarize our previously reported transmission spectra and LIDT test results with 800 ps, 8 ps and 675 fs pulses for these two coatings, and present a table of the LIDT results we have for all of our TiO2/SiO2 BBHR coatings, showing the trends with test laser pulse duration from the ns to sub-ps regimes.« less

  19. Optical conductivity measurements of GaTa4Se8 under high pressure: evidence of a bandwidth-controlled insulator-to-metal Mott transition.

    PubMed

    Ta Phuoc, V; Vaju, C; Corraze, B; Sopracase, R; Perucchi, A; Marini, C; Postorino, P; Chligui, M; Lupi, S; Janod, E; Cario, L

    2013-01-18

    The optical properties of a GaTa(4)Se(8) single crystal are investigated under high pressure. At ambient pressure, the optical conductivity exhibits a charge gap of ≈0.12 eV and a broad midinfrared band at ≈0.55 eV. As pressure is increased, the low energy spectral weight is strongly enhanced and the optical gap is rapidly filled, pointing to an insulator to metal transition around 6 GPa. The overall evolution of the optical conductivity demonstrates that GaTa(4)Se(8) is a Mott insulator which undergoes a bandwidth-controlled Mott metal-insulator transition under pressure, in remarkably good agreement with theory. With the use of our optical data and ab initio band structure calculations, our results were successfully compared to the (U/D, T/D) phase diagram predicted by dynamical mean field theory for strongly correlated systems.

  20. High resolution infrared acquisitions droning over the LUSI mud eruption.

    NASA Astrophysics Data System (ADS)

    Di Felice, Fabio; Romeo, Giovanni; Di Stefano, Giuseppe; Mazzini, Adriano

    2016-04-01

    The use of low-cost hand-held infrared (IR) thermal cameras based on uncooled micro-bolometer detector arrays became more widespread during the recent years. Thermal cameras have the ability to estimate temperature values without contact and therefore can be used in circumstances where objects are difficult or dangerous to reach such as volcanic eruptions. Since May 2006 the Indonesian LUSI mud eruption continues to spew boiling mud, water, aqueous vapor, CO2, CH4 and covers a surface of nearly 7 km2. At this locality we performed surveys over the unreachable erupting crater. In the framework of the LUSI Lab project (ERC grant n° 308126), in 2014 and 2015, we acquired high resolution infrared images using a specifically equipped remote-controlled drone flying at an altitude of m 100. The drone is equipped with GPS and an autopilot system that allows pre-programming the flying path or designing grids. The mounted thermal camera has peak spectral sensitivity in LW wavelength (μm 10) that is characterized by low water vapor and CO2 absorption. The low distance (high resolution) acquisitions have a temperature detail every cm 40, therefore it is possible to detect and observe physical phenomena such as thermodynamic behavior, hot mud and fluids emissions locations and their time shifts. Despite the harsh logistics and the continuously varying gas concentrations we managed to collect thermal images to estimate the crater zone spatial thermal variations. We applied atmosphere corrections to calculate infrared absorption by high concentration of water vapor. Thousands of images have been stitched together to obtain a mosaic of the crater zone. Regular monitoring with heat variation measurements collected, e.g. every six months, could give important information about the volcano activity estimating its evolution. A future data base of infrared high resolution and visible images stored in a web server could be a useful monitoring tool. An interesting development will be

  1. First results from IRENI - Rapid diffraction-limited high resolution imaging across the mid-infrared bandwidth

    SciTech Connect

    Nasse, Michael J.; Mattson, Eric; Hirschmugl, Carol

    2010-02-03

    First results from IRENI, a new beamline at the Synchrotron Radiation Center, demonstrate that synchrotron chemical imaging, which combines the characteristics of bright, stable, broadband synchrotron source with a multi-element detector, produces diffraction-limited images at all wavelengths simultaneously. A single cell of Micrasterias maintained in a flow cell has been measured, and results show high quality spectra and images demonstrating diffraction limited, and therefore wavelength-dependent, spatial resolution.

  2. Highly variable acquisition rates of Ixodes scapularis (Acari: Ixodidae) by birds on an Atlantic barrier island.

    PubMed

    Mitra, S S; Buckley, P A; Buckley, F G; Ginsberg, H S

    2010-11-01

    Acquisition of ticks by bird hosts is a central process in the transmission cycles of many tick-borne zoonoses, but tick recruitment by birds has received little direct study. We documented acquisition of Ixodes scapularis Say on birds at Fire Island, NY, by removing ticks from mist-netted birds, and recording the number of ticks on birds recaptured within 4 d of release. Eight bird species acquired at least 0.8 ticks bird(-1) day(-1) during the seasonal peak for at least one age class of I. scapularis. Gray Catbirds, Eastern Towhees, Common Yellowthroats, and Northern Waterthrushes collectively accounted for 83% of all tick acquisitions; and six individuals apportioned among Black-billed Cuckoo, Gray Catbird, Eastern Towhee, and Common Yellowthroat were simultaneously infested with both larvae and nymphs. Bird species with the highest acquisition rates were generally ground foragers, whereas birds that did not acquire ticks in our samples generally foraged above the ground. Tick acquisition by birds did not differ between deciduous and coniferous forests. Among the 15 bird species with the highest recruitment rates, acquisition of nymphs was not correlated with acquisition of larvae. Tick acquisition rates by individual bird species were not correlated with the reservoir competence of those species for Lyme borreliae. However, birds with high tick acquisition rates can contribute large numbers of infected ticks, and thus help maintain the enzootic cycle, even if their levels of reservoir competence are relatively low.

  3. Live Educational Outreach for Ocean Exploration: High-Bandwidth Ship-to-Shore Broadcasts Using Internet2

    NASA Astrophysics Data System (ADS)

    Coleman, D. F.; Ballard, R. D.

    2005-12-01

    During the past 3 field seasons, our group at the University of Rhode Island Graduate School of Oceanography, in partnership with the Institute for Exploration and a number of educational institutions, has conducted a series of ocean exploration expeditions with a significant focus on educational outreach through "telepresence" - utilizing live transmissions of video, audio, and data streams across the Internet and Internet2. Our educational partners include Immersion Presents, Boys and Girls Clubs of America, the Jason Foundation for Education, and the National Geographic Society, all who provided partial funding for the expeditions. The primary funding agency each year was NOAA's Office of Ocean Exploration and our outreach efforts were conducted in collaboration with them. During each expedition, remotely operated vehicle (ROV) systems were employed to examine interesting geological and archaeological sites on the seafloor. These expeditions include the investigation of ancient shipwrecks in the Black Sea in 2003, a survey of the Titanic shipwreck site in 2004, and a detailed sampling and mapping effort at the Lost City Hydrothermal Field in 2005. High-definition video cameras on the ROVs collected the footage that was then digitally encoded, IP-encapsulated, and streamed across a satellite link to a shore-based hub, where the streams were redistributed. During each expedition, live half-hour-long educational broadcasts were produced 4 times per day for 10 days. These shows were distributed using satellite and internet technologies to a variety of venues, including museums, aquariums, science centers, public schools, and universities. In addition to the live broadcasts, educational products were developed to enhance the learning experience. These include activity modules and curriculum-based material for teachers and informal educators. Each educational partner also maintained a web site that followed the expedition and provided additional background information

  4. Analytical design of a high bandwidth optoelectronic signal link for use in an EMP (electromagnetic pulse) plus radiation environment

    SciTech Connect

    Anthes, J.P.

    1988-01-01

    Electronic systems which must operate in an electromagnetic pulse (EMP) environment are often enclosed in a conducting box, or Faraday enclosure. The conducting walls must have apertures to allow communications with systems outside the enclosure. EMP leakage is minimized when the aperture diameter is small and has finite thickness. In addition, the penetration of a Faraday enclosure by a conductor may result in a significant portion of EMP induced noise inside the enclosure. Optical signals, because of their short wavelength, can efficiently traverse apertures that are highly attenuating to EMP signals. A communication link consisting of a GaAlAs laser diode source, optical fiber, and a photodiode detector is well suited to this application. Optical transport efficiency between an optical-fiber-coupled 10-stripe laser diode array and a radiation tolerant AlGaAs photodiode is optimized with a graded refractive index (GRIN) rod lens. The lens is positioned in the conducting wall of a Faraday enclosure. The radiation tolerant photodiode is contained inside the enclosure to control EMP induced degradation of the signal-to-noise ratio of the link. The AlGaAs photodiode double heterostructure design controls the ionizing-radiation-induced degradation of the link. An optical design analysis is performed to satisfy two criteria. First we select acceptable lens length-to-radius ratios for an aperture filled by a dielectric medium (the glass GRIN-rod lens). This criteria determines the upper limit on potential EMP leakage through the lens and into the Faraday enclosure. Second, we utilize the lens image condition to achieve 98% optical transfer between a nanosecond response, optical-fiber-coupled laser diode and the radiation hardened photodiode. 15 refs., 6 figs.

  5. Experimental and analytical study of a high gain self amplified spontaneous emission free electron laser operating in a large spectral bandwidth regime

    NASA Astrophysics Data System (ADS)

    Andonian, Gerard Cosmos

    The drive to create and measure ultra-short pulses in the x-ray regime advances the ongoing development of free electron lasers (FEL). Several proposed schemes, to shorten the pulse length of the radiation, involve driving the FEL with a chirped (linear longitudinal phase space correlation) electron beam in the self amplified spontaneous emission (SASE) mode. This dissertation examines the experiments conducted under such conditions, canvassing analytical and numerical studies of beam dynamics and radiation properties, experimental observations, and descriptions of the development of novel diagnostics. The VISA (Visible-Infrared SASE Amplifier) program has achieved saturation at 840 nm within a 4 m long undulator. A novel bunch compression mechanism during transport was discovered and ultimately responsible for the high peak current required to drive the FEL. Start-to-end simulations, detailing the dynamics from electron beam inception at the photocathode to the FEL radiation properties at the undulator, were successfully benchmarked to observable data. The VISA II experiment is an extension of this SASE FEL operating under different experimental conditions. Driving the SASE FEL with a chirped electron beam requires maintaining the chirp throughout transport by the use of sextupole magnets to correct for second-order compression effects. The emitted radiation is frequency chirped, diagnosed via a modified frequency resolved optical gating (FROG) technique. Specific numerical simulations and diagnostic developments are presented. A set of measurements, without sextupole corrections, displays anomalous features, namely large spectral bandwidth of the radiation at stable and sustained high gain lasing. The bandwidth has an rms value of 21 nm (12% full width), previously unobserved in a FEL. In addition, the far-field angular distribution yields a hollow mode structure, similar to earlier results yet more pronounced in angle. Start-to-end simulations reproduced the

  6. NSF Ocean Observatories Initiative's Contribution to a Fully Regional, Interactive, High-Bandwidth, Sensing-Robot System off the Washington-Oregon-British Columbia Coastline

    NASA Astrophysics Data System (ADS)

    Delaney, J. R.; Barletto, P.; Kelley, D.; Harkins, G.; Harrington, M.; Durand, C.; Mulvihill, M.; Penrose, N.; McGuire, C.; Daly, K. L.; Luther, D.; Kawka, O.; Proskurowski, G.; Fundis, A. T.

    2012-12-01

    included jointing a 10-km-long primary cable with a stub end into the node located in the middle of the Juan de Fuca Plate. This primary node has minimal internal electronics for now, but could be made fully operational with fairly minimal effort and cost at a later date by installing a full scientific interface assembly in the existing node frame. The 10-km stub-end cable will enable expansion using a cable splice, thereby avoiding the need for recovering the node itself. Scheduled for installation in summer 2013-14 is a major portion of the Secondary Infrastructure: 60 km of extension cables, five low-voltage nodes, 17 junction boxes, and four full-ocean water-column moorings with shallow- and deep-water profilers. Of the moorings, one will be installed at 3,000 m water depth at the Axial Seamount study site, one at 3,000 meters at base of the continental slope near Hydrate Ridge, and two hybrid units on the Endurance Array's Newport Line. In concert with NEPTUNE Canada, this OOI RSN cabled system creates a suite of unique opportunities for sustained, high-resolution, high-bandwidth, regional scientific investigations to be conducted in real-time throughout entire volumes of the NE Pacific Ocean with emphasis on the complexity of real ecosystems over the coming decades.

  7. Visualization of High Resolution Spatial Mass Spectrometric Data during Acquisition

    SciTech Connect

    Thomas, Mathew; Heath, Brandi S.; Laskin, Julia; Li, Dongsheng; Liu, Ellen C.; Hui, Katrina L.; Kuprat, Andrew P.; Kleese van Dam, Kerstin; Carson, James P.

    2012-08-28

    Mass Spectrometric Imaging (IMS) allows the generation of 2D ion density maps that help visualize molecules present in sections of tissues and cells. The combination of spatial and mass resolution results in large and complex data sets that require powerful and efficient analysis and interpretation. In this paper, a graphical user interface (GUI) that can visualize the large data during data acquisition itself is presented. The program also has the ability to perform processing and analysis of the dataset. The various functions of the GUI including visualization of mass spectra, generation of 2D maps for selected species, manipulation of the heat maps, and peak identification are also presented.

  8. Kinematic high bandwidth mirror mount

    DOEpatents

    Kuklo, T.C.

    1995-03-21

    An adjustable mirror mount system for a mirror is disclosed comprising a mirror support having a planar surface thereon, a mirror frame containing a mirror and having a planar surface behind the mirror facing the planar surface of the mirror support and parallel to the reflecting surface of the mirror and mounted pivotally to the mirror support at a point central to the frame, a first adjustment means between the mirror support and the mirror frame spaced from the central pivot mount for adjusting the movement of the mirror along one axis lying in the plane of the planar surface of the mirror frame; and a second adjustment means between the mirror support and the mirror frame spaced from the central pivot mount for adjusting the movement of the mirror along a second axis lying in the plane of the planar surface of the mirror frame and perpendicular to the first axis. 7 figures.

  9. Kinematic high bandwidth mirror mount

    DOEpatents

    Kuklo, Thomas C.

    1995-01-01

    An adjustable mirror mount system for a mirror is disclosed comprising a mirror support having a planar surface thereon, a mirror frame containing a mirror and having a planar surface behind the mirror facing the planar surface of the mirror support and parallel to the reflecting surface of the mirror and mounted pivotally to the mirror support at a point central to the frame, a first adjustment means between the mirror support and the mirror frame spaced from the central pivot mount for adjusting the movement of the mirror along one axis lying in the plane of the planar surface of the mirror frame; and a second adjustment means between the mirror support and the mirror frame spaced from the central pivot mount for adjusting the movement of the mirror along a second axis lying in the plane of the planar surface of the mirror frame and perpendicular to the first axis.

  10. The application of a computer data acquisition system for a new high temperature tribometer

    NASA Technical Reports Server (NTRS)

    Bonham, Charles D.; Dellacorte, Christopher

    1990-01-01

    The two data acquisition computer programs are described which were developed for a high temperature friction and wear test apparatus, a tribometer. The raw data produced by the tribometer and the methods used to sample that data are explained. In addition, the instrumentation and computer hardware and software are presented. Also shown is how computer data acquisition was applied to increase convenience and productivity on a high temperature tribometer.

  11. Optimum design of wide-bandwidth, low-noise photodiode amplifiers. Volume 1: Bandwidth

    NASA Astrophysics Data System (ADS)

    Hamilton, D. K.

    A circuit with video applications was tested. A reversed biased junction is a parallel combination of resistance and capacitance, which varies with the applied reverse voltage. The complete equivalent circuit model includes these components in parallel with a current generator. For optimum response at high frequency critical damping is necessary. The circuit allows the use of an amplifier with a wider open loop bandwidth than one compensated for unity gain, with a corresponding increase in system bandwidth.

  12. Ultrahigh bandwidth signal processing

    NASA Astrophysics Data System (ADS)

    Oxenløwe, Leif Katsuo

    2016-04-01

    Optical time lenses have proven to be very versatile for advanced optical signal processing. Based on a controlled interplay between dispersion and phase-modulation by e.g. four-wave mixing, the processing is phase-preserving, and hence useful for all types of data signals including coherent multi-level modulation formats. This has enabled processing of phase-modulated spectrally efficient data signals, such as orthogonal frequency division multiplexed (OFDM) signals. In that case, a spectral telescope system was used, using two time lenses with different focal lengths (chirp rates), yielding a spectral magnification of the OFDM signal. Utilising such telescopic arrangements, it has become possible to perform a number of interesting functionalities, which will be described in the presentation. This includes conversion from OFDM to Nyquist WDM, compression of WDM channels to a single Nyquist channel and WDM regeneration. These operations require a broad bandwidth nonlinear platform, and novel photonic integrated nonlinear platforms like aluminum gallium arsenide nano-waveguides used for 1.28 Tbaud optical signal processing will be described.

  13. Improved-Bandwidth Transimpedance Amplifier

    NASA Technical Reports Server (NTRS)

    Chapsky, Jacob

    2009-01-01

    The widest available operational amplifier, with the best voltage and current noise characteristics, is considered for transimpedance amplifier (TIA) applications where wide bandwidth is required to handle fast rising input signals (as for time-of-flight measurement cases). The added amplifier inside the TIA feedback loop can be configured to have slightly lower voltage gain than the bandwidth reduction factor.

  14. VisIO: enabling interactive visualization of ultra-scale, time-series data via high-bandwidth distributed I/O systems

    SciTech Connect

    Mitchell, Christopher J; Ahrens, James P; Wang, Jun

    2010-10-15

    Petascale simulations compute at resolutions ranging into billions of cells and write terabytes of data for visualization and analysis. Interactive visuaUzation of this time series is a desired step before starting a new run. The I/O subsystem and associated network often are a significant impediment to interactive visualization of time-varying data; as they are not configured or provisioned to provide necessary I/O read rates. In this paper, we propose a new I/O library for visualization applications: VisIO. Visualization applications commonly use N-to-N reads within their parallel enabled readers which provides an incentive for a shared-nothing approach to I/O, similar to other data-intensive approaches such as Hadoop. However, unlike other data-intensive applications, visualization requires: (1) interactive performance for large data volumes, (2) compatibility with MPI and POSIX file system semantics for compatibility with existing infrastructure, and (3) use of existing file formats and their stipulated data partitioning rules. VisIO, provides a mechanism for using a non-POSIX distributed file system to provide linear scaling of 110 bandwidth. In addition, we introduce a novel scheduling algorithm that helps to co-locate visualization processes on nodes with the requested data. Testing using VisIO integrated into Para View was conducted using the Hadoop Distributed File System (HDFS) on TACC's Longhorn cluster. A representative dataset, VPIC, across 128 nodes showed a 64.4% read performance improvement compared to the provided Lustre installation. Also tested, was a dataset representing a global ocean salinity simulation that showed a 51.4% improvement in read performance over Lustre when using our VisIO system. VisIO, provides powerful high-performance I/O services to visualization applications, allowing for interactive performance with ultra-scale, time-series data.

  15. Compact antenna arrays with wide bandwidth and low sidelobe levels

    DOEpatents

    Strassner, II, Bernd H.

    2014-09-09

    Highly efficient, low cost, easily manufactured SAR antenna arrays with lightweight low profiles, large instantaneous bandwidths and low SLL are disclosed. The array topology provides all necessary circuitry within the available antenna aperture space and between the layers of material that comprise the aperture. Bandwidths of 15.2 GHz to 18.2 GHz, with 30 dB SLLs azimuthally and elevationally, and radiation efficiencies above 40% may be achieved. Operation over much larger bandwidths is possible as well.

  16. Investigation of High-Level Synthesis tools’ applicability to data acquisition systems design based on the CMS ECAL Data Concentrator Card example

    NASA Astrophysics Data System (ADS)

    HUSEJKO, Michal; EVANS, John; RASTEIRO DA SILVA, Jose Carlos

    2015-12-01

    High-Level Synthesis (HLS) for Field-Programmable Logic Array (FPGA) programming is becoming a practical alternative to well-established VHDL and Verilog languages. This paper describes a case study in the use of HLS tools to design FPGA-based data acquisition systems (DAQ). We will present the implementation of the CERN CMS detector ECAL Data Concentrator Card (DCC) functionality in HLS and lessons learned from using HLS design flow. The DCC functionality and a definition of the initial system-level performance requirements (latency, bandwidth, and throughput) will be presented. We will describe how its packet processing control centric algorithm was implemented with VHDL and Verilog languages. We will then show how the HLS flow could speed up design-space exploration by providing loose coupling between functions interface design and functions algorithm implementation. We conclude with results of real-life hardware tests performed with the HLS flow-generated design with a DCC Tester system.

  17. Big Bandwidth Battle: Universal ADSL Looks Ahead.

    ERIC Educational Resources Information Center

    Hargadon, Tom

    1998-01-01

    Discusses the new Universal ADSL (Asymmetric Digital Subscriber Line) standard, which promises simple, high-bandwidth access over standard telephone lines. Topics include varieties of DSL; voice and data capacities; adapters and installation for personal computers; Internet backbone capacity; and headend access. (LRW)

  18. High energy pulses generation with giant spectrum bandwidth and submegahertz repetition rate from a passively mode-locked Yb-doped fiber laser in all normal dispersion cavity

    NASA Astrophysics Data System (ADS)

    Lin, J.-H.; Wang, D.; Lin, K.-H.

    2011-01-01

    Robust passively mode-locked pulse generation with low pulse repetition rate and giant spectrum bandwidth in an all-fiber, all-normal-dispersion ytterbium-doped fiber laser has been experimentally demonstrated using nonlinear polarization evolution technique. The highest pulse energy over 20 nJ with spectrum bandwidth over 50 nm can be experimentally obtained at 175 mW pump power. The mode-locked pulses reveal broadened 3-dB pulsewidth about several nanosecond and widened pedestal in time trace that is resulted from enormous dispersion in laser cavity and gain dynamics. At certain mode-locking state, a spectrum gap around 1056 nm are observed between the three and four energy levels of Yb-doped fiber laser. By properly rotating the polarization controller, the gap can be eliminated due to four-wave mixing to produce more flattened spectrum output.

  19. Co-scheduling of network resource provisioning and host-to-host bandwidth reservation on high-performance network and storage systems

    DOEpatents

    Yu, Dantong; Katramatos, Dimitrios; Sim, Alexander; Shoshani, Arie

    2014-04-22

    A cross-domain network resource reservation scheduler configured to schedule a path from at least one end-site includes a management plane device configured to monitor and provide information representing at least one of functionality, performance, faults, and fault recovery associated with a network resource; a control plane device configured to at least one of schedule the network resource, provision local area network quality of service, provision local area network bandwidth, and provision wide area network bandwidth; and a service plane device configured to interface with the control plane device to reserve the network resource based on a reservation request and the information from the management plane device. Corresponding methods and computer-readable medium are also disclosed.

  20. A high speed PC-based data acquisition and control system for positron imaging

    NASA Astrophysics Data System (ADS)

    Leadbeater, T. W.; Parker, D. J.

    2009-06-01

    A modular positron camera with a flexible geometry suitable for performing Positron Emission Particle Tracking (PEPT) studies on a wide range of applications has been constructed. The demand for high speed list mode data storage required for these experiments has motivated the development of an improved data acquisition system to support the existing detectors. A high speed PC-based data acquisition system is presented. This device replaces the old dedicated hardware with a compact, flexible device with the same functionality and superior performance. Data acquisition rates of up to 80 MBytes per second allow coincidence data to be saved to disk for real-time analysis or post processing. The system supports the storage of time information with resolution of a half millisecond and remote trigger data support. Control of the detector system is provided by high-level software running on the same computer.

  1. Eye-Movement Tracker Would Reduce Video Bandwidth

    NASA Technical Reports Server (NTRS)

    Ruoff, C. F.

    1985-01-01

    Bandwidth required to transmit closed circuit television image reduced by transmitting small portion at high resolution and remainder at low resolution. High-resolution portion centered in viewer's gaze so entire image seems to be of high resolution.

  2. Multiplex acquisition approach for high speed 3D measurements with a chromatic confocal microscope

    NASA Astrophysics Data System (ADS)

    Taphanel, Miro; Zink, Ralf; Längle, Thomas; Beyerer, Jürgen

    2015-05-01

    A technical realization of a multispectral camera is proposed, by multiplexing a light source with six different spectra. A monochrome line scan camera with six pixel rows is used as detector. The special feature of this acquisition approach is its high speed capability. The scan speed is as high as the frame rate of the line scan camera and not affected by the multiplexing. As application a chromatic confocal microscope was build up. From a data acquisition perspective up to 284 million 3D points per second can be measured. A real time signal processing is proposed, too.

  3. Spectral bandwidth and ocular accommodation

    NASA Astrophysics Data System (ADS)

    Aggarwala, Karan R.; Kruger, Ekaterina S.; Mathews, Steven; Kruger, Philip B.

    1995-03-01

    Previous studies have suggested that targets illuminated by monochromatic (narrow-band) light are less effective in stimulating the eye to change its focus than are black-white (broadband) targets. The present study investigates the influence of target spectral bandwidth on the dynamic accommodation response in eight subjects. The fixation target was a 3.5-cycle / deg square-wave grating illuminated by midspectral light of various bandwidths [10, 40, and 80 nm and white (CIE Illuminant B)]. The target was moved sinusoidally toward and away from the eye, and accommodation responses were recorded and Fourier analyzed. Accommodative gain increases, and phase lag decreases, with increasing spectral bandwidth. Thus the eye focuses more accurately on targets of wider spectral bandwidth. The visual system appears to have the ability to analyze polychromatic blur to determine the state of focus of the eye for the purpose of guiding the accommodation response. blur, chromatic, focus, retinal image, spectral, wavelength

  4. Combining high performance simulation, data acquisition, and graphics display computers

    NASA Technical Reports Server (NTRS)

    Hickman, Robert J.

    1989-01-01

    Issues involved in the continuing development of an advanced simulation complex are discussed. This approach provides the capability to perform the majority of tests on advanced systems, non-destructively. The controlled test environments can be replicated to examine the response of the systems under test to alternative treatments of the system control design, or test the function and qualification of specific hardware. Field tests verify that the elements simulated in the laboratories are sufficient. The digital computer is hosted by a Digital Equipment Corp. MicroVAX computer with an Aptec Computer Systems Model 24 I/O computer performing the communication function. An Applied Dynamics International AD100 performs the high speed simulation computing and an Evans and Sutherland PS350 performs on-line graphics display. A Scientific Computer Systems SCS40 acts as a high performance FORTRAN program processor to support the complex, by generating numerous large files from programs coded in FORTRAN that are required for the real time processing. Four programming languages are involved in the process, FORTRAN, ADSIM, ADRIO, and STAPLE. FORTRAN is employed on the MicroVAX host to initialize and terminate the simulation runs on the system. The generation of the data files on the SCS40 also is performed with FORTRAN programs. ADSIM and ADIRO are used to program the processing elements of the AD100 and its IOCP processor. STAPLE is used to program the Aptec DIP and DIA processors.

  5. Multi-channel high-speed CMOS image acquisition and pre-processing system

    NASA Astrophysics Data System (ADS)

    Sun, Chun-feng; Yuan, Feng; Ding, Zhen-liang

    2008-10-01

    A new multi-channel high-speed CMOS image acquisition and pre-processing system is designed to realize the image acquisition, data transmission, time sequential control and simple image processing by high-speed CMOS image sensor. The modular structure design, LVDS and ping-pong cache techniques used during the designed image data acquisition sub-system design ensure the real-time data acquisition and transmission. Furthermore, a new histogram equalization algorithm of adaptive threshold value based on the reassignment of redundant gray level is incorporated in the image preprocessing module of FPGA. The iterative method is used in the course of setting threshold value, and a redundant graylevel is redistributed rationally according to the proportional gray level interval. The over-enhancement of background is restrained and the feasibility of mergence of foreground details is reduced. The experimental certificates show that the system can be used to realize the image acquisition, transmission, memory and pre-processing to 590MPixels/s data size, and make for the design and realization of the subsequent system.

  6. The LHCb Data Acquisition and High Level Trigger Processing Architecture

    NASA Astrophysics Data System (ADS)

    Frank, M.; Gaspar, C.; Jost, B.; Neufeld, N.

    2015-12-01

    The LHCb experiment at the LHC accelerator at CERN collects collisions of particle bunches at 40 MHz. After a first level of hardware trigger with an output rate of 1 MHz, the physically interesting collisions are selected by running dedicated trigger algorithms in the High Level Trigger (HLT) computing farm. This farm consists of up to roughly 25000 CPU cores in roughly 1750 physical nodes each equipped with up to 4 TB local storage space. This work describes the LHCb online system with an emphasis on the developments implemented during the current long shutdown (LS1). We will elaborate the architecture to treble the available CPU power of the HLT farm and the technicalities to determine and verify precise calibration and alignment constants which are fed to the HLT event selection procedure. We will describe how the constants are fed into a two stage HLT event selection facility using extensively the local disk buffering capabilities on the worker nodes. With the installed disk buffers, the CPU resources can be used during periods of up to ten days without beams. These periods in the past accounted to more than 70% of the total time.

  7. Bandwidth Enabled Flight Operations: Examining the Possibilities

    NASA Technical Reports Server (NTRS)

    Pisanich, Greg; Renema, Fritz; Clancy, Dan (Technical Monitor)

    2002-01-01

    The Bandwidth Enabled Flight Operations project is a research effort at the NASA Ames Research Center to investigate the use of satellite communications to improve aviation safety and capacity. This project is a follow on to the AeroSAPIENT Project, which demonstrated methods for transmitting high bandwidth data in various configurations. For this research, we set a goal to nominally use only 10 percent of the available bandwidth demonstrated by AeroSAPIENT or projected by near-term technology advances. This paper describes the results of our research, including available satellite bandwidth, commercial and research efforts to provide these services, and some of the limiting factors inherent with this communications medium. It also describes our investigation into the needs of the stakeholders (Airlines, Pilots, Cabin Crews, ATC, Maintenance, etc). The paper also describes our development of low-cost networked flight deck and airline operations center simulations that were used to demonstrate two application areas: Providing real time weather information to the commercial flight deck, and enhanced crew monitoring and control for airline operations centers.

  8. Workshop on data acquisition and trigger system simulations for high energy physics

    SciTech Connect

    1992-12-31

    This report discusses the following topics: DAQSIM: A data acquisition system simulation tool; Front end and DCC Simulations for the SDC Straw Tube System; Simulation of Non-Blocklng Data Acquisition Architectures; Simulation Studies of the SDC Data Collection Chip; Correlation Studies of the Data Collection Circuit & The Design of a Queue for this Circuit; Fast Data Compression & Transmission from a Silicon Strip Wafer; Simulation of SCI Protocols in Modsim; Visual Design with vVHDL; Stochastic Simulation of Asynchronous Buffers; SDC Trigger Simulations; Trigger Rates, DAQ & Online Processing at the SSC; Planned Enhancements to MODSEM II & SIMOBJECT -- an Overview -- R.; DAGAR -- A synthesis system; Proposed Silicon Compiler for Physics Applications; Timed -- LOTOS in a PROLOG Environment: an Algebraic language for Simulation; Modeling and Simulation of an Event Builder for High Energy Physics Data Acquisition Systems; A Verilog Simulation for the CDF DAQ; Simulation to Design with Verilog; The DZero Data Acquisition System: Model and Measurements; DZero Trigger Level 1.5 Modeling; Strategies Optimizing Data Load in the DZero Triggers; Simulation of the DZero Level 2 Data Acquisition System; A Fast Method for Calculating DZero Level 1 Jet Trigger Properties and Physics Input to DAQ Studies.

  9. A high speed data acquisition and analysis system for transonic velocity, density, and total temperature fluctuations

    NASA Technical Reports Server (NTRS)

    Clukey, Steven J.

    1988-01-01

    The high speed Dynamic Data Acquisition System (DDAS) is described which provides the capability for the simultaneous measurement of velocity, density, and total temperature fluctuations. The system of hardware and software is described in context of the wind tunnel environment. The DDAS replaces both a recording mechanism and a separate data processing system. The data acquisition and data reduction process has been combined within DDAS. DDAS receives input from hot wires and anemometers, amplifies and filters the signals with computer controlled modules, and converts the analog signals to digital with real-time simultaneous digitization followed by digital recording on disk or tape. Automatic acquisition (either from a computer link to an existing wind tunnel acquisition system, or from data acquisition facilities within DDAS) collects necessary calibration and environment data. The generation of hot wire sensitivities is done in DDAS, as is the application of sensitivities to the hot wire data to generate turbulence quantities. The presentation of the raw and processed data, in terms of root mean square values of velocity, density and temperature, and the processing of the spectral data is accomplished on demand in near-real-time- with DDAS. A comprehensive description of the interface to the DDAS and of the internal mechanisms will be prosented. A summary of operations relevant to the use of the DDAS will be provided.

  10. Sources of Knowledge Acquisition: Perspectives of the High School Teacher/Coach

    ERIC Educational Resources Information Center

    Wilson, Laurie M.; Bloom, Gordon A.; Harvey, William J.

    2010-01-01

    Background: Research on coach development and knowledge acquisition has traditionally focused on those working at either university or Olympic levels. Despite the large body of research using these participants, there are relatively few empirical studies on the knowledge development of high school coaches, in particular, physical education…

  11. Investigating Knowledge Acquisition and Developing Misconceptions of High School Students Enrolled in an Invasion Games Unit

    ERIC Educational Resources Information Center

    Hare, Molly K.; Graber, Kim C.

    2007-01-01

    Grounded within constructivist theory, the purpose of this investigation was to investigate knowledge acquisition and developing conceptions of high school-aged students during a unit of instruction in badminton. Six different qualitative methods were utilized: (a) observations, (b) formal interviews, (c) informal interviews, (d) think aloud…

  12. Low Bandwidth Techniques for Remote Observing

    NASA Astrophysics Data System (ADS)

    Percival, Jeffrey W.

    1994-12-01

    Remote Observing is an ill-defined concept that means different things to different people. For some, it means automated observing. To others, it means simple eavesdropping during observations. Some people even define it to be unachievable, independent of bandwidth or other resources, until the smell of a burning resistor can be sent over a wire. In designing the WIYN 3.5m Telescope Control System, we have decided to avoid defining Remote Observing, and have instead simply set about to chip away at the problem by designing a network-transparent command and control system, a spacecraft-style platform-independent telemetry system, and an innovative method of image compression that lends itself to the progressive transmission of large digital images over low-bandwidth communications links. We found that our users were quite happy with the capabilities of the system. Engineers found they could measure plant response and tune servo loops from half a continent away. Control System designers could monitor operations without disturbing the use of the telescope by on-site personnel. Large images could be sent from the observatory for quick-look analysis or target acquisition in a way that provided useful images in a short time, with an observatory bandwidth requirement that is independent of the number of recipients of the image. The WIYN Telescope will begin science operations in 1995, and time will tell which of these features turn out to be popular with the observers. Rather than remove the astronomer from the dome, they may promote more collaborative observing, provide for more effective observations of targets of opportunity, or allow easy and effective access for students of all types to address important educational objectives of home institutions.

  13. Narrow-bandwidth unstable laser resonator

    SciTech Connect

    Reintjes, J.F.; Tankersley, L.L.; Cooper, D.

    1988-10-21

    The present invention relates to unstable laser resonators, particularly to unstable laser resonators, and particularly to an unstable laser resonator that produces optical radiation that simultaneously has the high output power diffraction-limited divergence characteristic of an unstable laser resonator and also the narrow bandwidth that can usually be obtained only with a stable laser resonator. Some success was achieved in the frequency narrowing of the laser radiation from an unstable laser resonator cavity by using a diffraction grating. This technique was works best with lasers that have sharp line structure, such as molecular lasers. For example, selection of a single line in a hydrogen-fluoride laser has been reported in several configurations involving the insertion of a diffraction grating into a standard unstable laser resonator cavity. Although currently available, unstable laser resonators have the configuration of choice for producing high-power, low-divergence radiation from laser cavities; they are not compatible with a simultaneous requirement of narrow bandwidth.

  14. Steel Industry Energy Bandwidth Study

    SciTech Connect

    none,

    2004-10-01

    ITP conducted a study on energy use and potential savings, or "bandwidth" study, in major steelmaking processes. Intended to provide a realistic estimate of the potential amount of energy that can be saved in an industrial process, the "bandwidth" refers to the difference between the amount of energy that would be consumed in a process using commercially available technology versus the minimum amount of energy needed to achieve those same results based on the 2nd law of thermodynamics. The Steel Industry Energy Bandwidth Study (PDF 133 KB) also estimates steel industry energy use in the year 2010, and uses that value as a basis for comparison against the minimum requirements. This energy savings opportunity for 2010 will aid focus on longer term R&D.

  15. High-speed highly-flexible reconfigurable data acquisition system for astronomy

    NASA Astrophysics Data System (ADS)

    Pirger, Bruce E.; Schoenwald, Justin; Herter, Terry L.; Gull, George E.; Adams, Joseph D.; Keller, Luke D.; Berthoud, Marc; Henderson, Charles; Stacy, Gordon J.; Nikola, Thomas

    2006-06-01

    We have developed a high speed, flexible, data acquisition system and targeted it to astronomical imaging. The system is based on Field Programmable Gate Arrays (FPGAs) and provides a gigabit/sec fiber optic link between the electronics located on the instrument and the host computer. The FPGAs are reconfigurable over the fiber optic link for maximum flexibility. The system has initially been targeted at DRS Technologies' 256x256 Si:As and Si:Sb detectors used in FORCAST1, a mid-IR camera/spectrograph built by Cornell University for SOFIA. The initial configuration provides sixteen parallel channels of six Msamples/second 14-bit analog to digital converters. The system can coadd 256x256 images at over 1000 frames per second in up to 64 different memory positions. Array clocking and sampling is generated from uploaded clocking patterns in two independent memories. This configuration allows the user to quickly create, on the fly, any form of array clocking and sampling (destructive, non-destructive, sample up the ramp, additional reset frames, Fowler, single frames, co-added frames, multi-position chop, throw away frames, etc.) The electronics were designed in a modular fashion so that any number of analog channels from arrays or mosaics of arrays can be accommodated by using the appropriate number of FPGA boards and preamps. The preamp/analog to digital converter boards can be replaced as needed to operate any focal plane array or other sensor. The system also provides analog drive capability for controlling an X-Y chopping secondary mirror, nominal two position chopping, and can also synchronize to an externally driven chop source. Multiple array controllers can be synchronized together, allowing multi-channel systems to share a single chopping secondary, yet clock the focal planes differently from each other. Due to the flexibility of the FPGAs, it is possible to develop highly customized operating modes to maximize system performance or to enable novel

  16. A flexible high-rate USB2 data acquisition system for PET and SPECT imaging

    SciTech Connect

    J. Proffitt, W. Hammond, S. Majewski, V. Popov, R.R. Raylman, A.G. Weisenberger, R. Wojcik

    2006-02-01

    A new flexible data acquisition system has been developed to instrument gamma-ray imaging detectors designed by the Jefferson Lab Detector and Imaging Group. Hardware consists of 16-channel data acquisition modules installed on USB2 carrier boards. Carriers have been designed to accept one, two, and four modules. Application trigger rate and channel density determines the number of acquisition boards and readout computers used. Each channel has an independent trigger, gated integrator and a 2.5 MHz 12-bit ADC. Each module has an FPGA for analog control and signal processing. Processing includes a 5 ns 40-bit trigger time stamp and programmable triggering, gating, ADC timing, offset and gain correction, charge and pulse-width discrimination, sparsification, event counting, and event assembly. The carrier manages global triggering and transfers module data to a USB buffer. High-granularity time-stamped triggering is suitable for modular detectors. Time stamped events permit dynamic studies, complex offline event assembly, and high-rate distributed data acquisition. A sustained USB data rate of 20 Mbytes/s, a sustained trigger rate of 300 kHz for 32 channels, and a peak trigger rate of 2.5 MHz to FIFO memory were achieved. Different trigger, gating, processing, and event assembly techniques were explored. Target applications include >100 kHz coincidence rate PET detectors, dynamic SPECT detectors, miniature and portable gamma detectors for small-animal and clinical use.

  17. Data acquisition and analysis procedures for high-resolution atomic force microscopy in three dimensions.

    PubMed

    Albers, Boris J; Schwendemann, Todd C; Baykara, Mehmet Z; Pilet, Nicolas; Liebmann, Marcus; Altman, Eric I; Schwarz, Udo D

    2009-07-01

    Data acquisition and analysis procedures for noncontact atomic force microscopy that allow the recording of dense three-dimensional (3D) surface force and energy fields with atomic resolution are presented. The main obstacles for producing high-quality 3D force maps are long acquisition times that lead to data sets being distorted by drift, and tip changes. Both problems are reduced but not eliminated by low-temperature operation. The procedures presented here employ an image-by-image data acquisition scheme that cuts measurement times by avoiding repeated recording of redundant information, while allowing post-acquisition drift correction. All steps are detailed with the example of measurements performed on highly oriented pyrolytic graphite in ultrahigh vacuum at a temperature of 6 K. The area covered spans several unit cells laterally and vertically from the attractive region to where no force could be measured. The resulting fine data mesh maps piconewton forces with <7 pm lateral and<2 pm vertical resolution. From this 3D data set, two-dimensional cuts along any plane can be plotted. Cuts in a plane parallel to the sample surface show atomic resolution, while cuts along the surface normal visualize how the attractive atomic force fields extend into vacuum. At the same time, maps of the tip-sample potential energy, the lateral tip-sample forces, and the energy dissipated during cantilever oscillation can be produced with identical resolution.

  18. Mining Industry Energy Bandwidth Study

    SciTech Connect

    none,

    2007-07-01

    The Industrial Technologies Program (ITP) relies on analytical studies to identify large energy reduction opportunities in energy-intensive industries and uses these results to guide its R&D portfolio. The energy bandwidth illustrates the total energy-saving opportunity that exists in the industry if the current processes are improved by implementing more energy-efficient practices and by using advanced technologies. This bandwidth analysis report was conducted to assist the ITP Mining R&D program in identifying energy-saving opportunities in coal, metals, and mineral mining. These opportunities were analyzed in key mining processes of blasting, dewatering, drilling, digging, ventilation, materials handling, crushing, grinding, and separations.

  19. 47 CFR 95.633 - Emission bandwidth.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Emission bandwidth. 95.633 Section 95.633... SERVICES Technical Regulations Technical Standards § 95.633 Emission bandwidth. (a) The authorized bandwidth (maximum permissible bandwidth of a transmission) for emission type H1D, J1D, R1D, H3E, J3E or...

  20. 47 CFR 95.633 - Emission bandwidth.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Emission bandwidth. 95.633 Section 95.633... SERVICES Technical Regulations Technical Standards § 95.633 Emission bandwidth. (a) The authorized bandwidth (maximum permissible bandwidth of a transmission) for emission type H1D, J1D, R1D, H3E, J3E or...

  1. High-Bandwidth AFM-Based Rheology Reveals that Cartilage is Most Sensitive to High Loading Rates at Early Stages of Impairment

    PubMed Central

    Nia, Hadi Tavakoli; Bozchalooi, Iman S.; Li, Yang; Han, Lin; Hung, Han-Hwa; Frank, Eliot; Youcef-Toumi, Kamal; Ortiz, Christine; Grodzinsky, Alan

    2013-01-01

    Utilizing a newly developed atomic-force-microscopy-based wide-frequency rheology system, we measured the dynamic nanomechanical behavior of normal and glycosaminoglycan (GAG)-depleted cartilage, the latter representing matrix degradation that occurs at the earliest stages of osteoarthritis. We observed unique variations in the frequency-dependent stiffness and hydraulic permeability of cartilage in the 1 Hz-to-10 kHz range, a frequency range that is relevant to joint motions from normal ambulation to high-frequency impact loading. Measurement in this frequency range is well beyond the capabilities of typical commercial atomic force microscopes. We showed that the dynamic modulus of cartilage undergoes a dramatic alteration after GAG loss, even with the collagen network still intact: whereas the magnitude of the dynamic modulus decreased two- to threefold at higher frequencies, the peak frequency of the phase angle of the modulus (representing fluid-solid frictional dissipation) increased 15-fold from 55 Hz in normal cartilage to 800 Hz after GAG depletion. These results, based on a fibril-reinforced poroelastic finite-element model, demonstrated that GAG loss caused a dramatic increase in cartilage hydraulic permeability (up to 25-fold), suggesting that early osteoarthritic cartilage is more vulnerable to higher loading rates than to the conventionally studied “loading magnitude”. Thus, over the wide frequency range of joint motion during daily activities, hydraulic permeability appears the most sensitive marker of early tissue degradation. PMID:23561529

  2. High Rates of Antimicrobial Drug Resistance Gene Acquisition after International Travel, the Netherlands

    PubMed Central

    von Wintersdorff, Christian J.H.; Penders, John; Stobberingh, Ellen E.; Lashof, Astrid M.L. Oude; Hoebe, Christian J.P.A.; Savelkoul, Paul H.M.

    2014-01-01

    We investigated the effect of international travel on the gut resistome of 122 healthy travelers from the Netherlands by using a targeted metagenomic approach. Our results confirm high acquisition rates of the extended-spectrum β-lactamase encoding gene blaCTX-M, documenting a rise in prevalence from 9.0% before travel to 33.6% after travel (p<0.001). The prevalence of quinolone resistance encoding genes qnrB and qnrS increased from 6.6% and 8.2% before travel to 36.9% and 55.7% after travel, respectively (both p<0.001). Travel to Southeast Asia and the Indian subcontinent was associated with the highest acquisition rates of qnrS and both blaCTX-M and qnrS, respectively. Investigation of the associations between the acquisitions of the blaCTX-M and qnr genes showed that acquisition of a blaCTX-M gene was not associated with that of a qnrB (p = 0.305) or qnrS (p = 0.080) gene. These findings support the increasing evidence that travelers contribute to the spread of antimicrobial drug resistance. PMID:24655888

  3. PCI express bus design of large format array IRFPA high-speed acquisition system

    NASA Astrophysics Data System (ADS)

    Huang, Zewu; Zheng, Xing; Zeng, Xingxin; Liu, Ziji

    2012-10-01

    In this paper, a novel solution of PCI Express Bus was designed to improve the data transfer rate for large format array infrared imaging acquisition system. In this structure, an embedded PCI Express hard intellectual property (IP) block of Stratix IV GX FPGA was used, and the protocol stack module is totally compliant with PCI Express base specification Gen 2.0 which includes PHY-MAC, Data Link, and transaction layers. In order to communicate with CPU through computer PCIe root port, a pipeline structure was established with two SSRAMs to carry out the function of real-time data process. The DMA mode was adopted for the high-speed data transmission on the PCI Express Bus. Some other control logic parts such as detector drive signal generator - display controller and PCIe configuration module were also designed and introduced in this paper. According to the evaluation, the data transmission speed was up to 5.6Gbps, which means that this system could meet the qualifications of infrared imaging data acquisition. Compared with traditional infrared imaging data acquisition systems, this solution is more integrated and faster, so it is suitable for larger format and higher frame rate of infrared focal plane image acquisition in nowadays and future.

  4. A high speed data acquisition system for the analysis of velocity, density, and total temperature fluctuations at transonic speeds

    NASA Technical Reports Server (NTRS)

    Clukey, Steven J.; Jones, Gregory S.; Stainback, P. Calvin

    1988-01-01

    The use of a high-speed Dynamic Data Acquisition System (DDAS) to measure simultaneously velocity, density, and total temperature fluctuations is described. The DDAS is used to automate the acquisition of hot-wire calibration data. The data acquisition, data handling, and data reporting techiques used by DDAS are described. Sample data are used to compare results obtained with the DDAS with those obtained from the FM tape and post-test digitization method.

  5. Developing Strategies for Affordable Bandwidth.

    ERIC Educational Resources Information Center

    Educause Quarterly, 2000

    2000-01-01

    Written by Educause's Net@EDU Broadband Pricing Working Group, this article discusses what institutions of higher education can do to develop good partnerships with broadband vendors in order to negotiate affordable pricing for increased bandwidth. Describes problems with the marketplace, examples from a few universities, and points to remember…

  6. Bandwidth efficient coding for satellite communications

    NASA Technical Reports Server (NTRS)

    Lin, Shu; Costello, Daniel J., Jr.; Miller, Warner H.; Morakis, James C.; Poland, William B., Jr.

    1992-01-01

    An error control coding scheme was devised to achieve large coding gain and high reliability by using coded modulation with reduced decoding complexity. To achieve a 3 to 5 dB coding gain and moderate reliability, the decoding complexity is quite modest. In fact, to achieve a 3 dB coding gain, the decoding complexity is quite simple, no matter whether trellis coded modulation or block coded modulation is used. However, to achieve coding gains exceeding 5 dB, the decoding complexity increases drastically, and the implementation of the decoder becomes very expensive and unpractical. The use is proposed of coded modulation in conjunction with concatenated (or cascaded) coding. A good short bandwidth efficient modulation code is used as the inner code and relatively powerful Reed-Solomon code is used as the outer code. With properly chosen inner and outer codes, a concatenated coded modulation scheme not only can achieve large coding gains and high reliability with good bandwidth efficiency but also can be practically implemented. This combination of coded modulation and concatenated coding really offers a way of achieving the best of three worlds, reliability and coding gain, bandwidth efficiency, and decoding complexity.

  7. Fast acquisition of high-resolution 2D NMR spectroscopy in inhomogeneous magnetic fields

    NASA Astrophysics Data System (ADS)

    Lin, Liangjie; Wei, Zhiliang; Zeng, Qing; Yang, Jian; Lin, Yanqin; Chen, Zhong

    2016-05-01

    High-resolution nuclear magnetic resonance (NMR) spectroscopy plays an important role in chemical and biological analyses. In this study, we combine the J-coupling coherence transfer module with the echo-train acquisition technique for fast acquisition of high-resolution 2D NMR spectra in magnetic fields with unknown spatial variations. The proposed method shows satisfactory performance on a 5 mM ethyl 3-bromopropionate sample, under a 5-kHz (10 ppm at 11.7 T) B0 inhomogeneous field, as well as under varying degrees of pulse-flip-angle deviations. Moreover, a simulative ex situ NMR measurement is also conducted to show the effectiveness of the proposed pulse sequence.

  8. High-resolution 2D NMR spectra in inhomogeneous fields via 3D acquisition

    NASA Astrophysics Data System (ADS)

    Lin, Yanqin; Wei, Zhiliang; Zhang, Liandi; Lin, Liangjie; Chen, Zhong

    2014-04-01

    High-resolution nuclear magnetic resonance (NMR) spectroscopy plays an important role in chemical studies. Here, a pulse sequence, based on coherence transfer module of tracking differences of precession frequencies of two spins and spin echo module, is proposed to obtain two dimension (2D) high-resolution NMR spectra via 3D acquisition under large field inhomogeneity. The proposed scheme composes of simple hard pulses and rectangle gradients. Resulting 2D spectra exhibit chemical shift differences and J coupling splittings in two orthogonal dimensions. The method developed here may offer a promising way for in situ high-resolution NMR studies on combinatorial chemistry.

  9. A wireless high-speed data acquisition system for geotechnical centrifuge model testing

    NASA Astrophysics Data System (ADS)

    Gaudin, C.; White, D. J.; Boylan, N.; Breen, J.; Brown, T.; DeCatania, S.; Hortin, P.

    2009-09-01

    This paper describes a novel high-speed wireless data acquisition system (WDAS) developed at the University of Western Australia for operation onboard a geotechnical centrifuge, in an enhanced gravitational field of up to 300 times Earth's gravity. The WDAS system consists of up to eight separate miniature units distributed around the circumference of a 0.8 m diameter drum centrifuge, communicating with the control room via wireless Ethernet. Each unit is capable of powering and monitoring eight instrument channels at a sampling rate of up to 1 MHz at 16-bit resolution. The data are stored within the logging unit in solid-state memory, but may also be streamed in real-time at low frequency (up to 10 Hz) to the centrifuge control room, via wireless transmission. The high-speed logging runs continuously within a circular memory (buffer), allowing for storage of a pre-trigger segment of data prior to an event. To suit typical geotechnical modelling applications, the system can record low-speed data continuously, until a burst of high-speed acquisition is triggered when an experimental event occurs, after which the system reverts back to low-speed acquisition to monitor the aftermath of the event. Unlike PC-based data acquisition solutions, this system performs the full sequence of amplification, conditioning, digitization and storage on a single circuit board via an independent micro-controller allocated to each pair of instrumented channels. This arrangement is efficient, compact and physically robust to suit the centrifuge environment. This paper details the design specification of the WDAS along with the software interface developed to control the units. Results from a centrifuge test of a submarine landslide are used to illustrate the performance of the new WDAS.

  10. Tunable-Bandwidth Filter System

    NASA Technical Reports Server (NTRS)

    Aye, Tin; Yu, Kevin; Dimov, Fedor; Savant, Gajendra

    2006-01-01

    A tunable-bandwidth filter system (TBFS), now undergoing development, is intended to be part of a remote-sensing multispectral imaging system that will operate in the visible and near infrared spectral region (wavelengths from 400 to 900 nm). Attributes of the TBFS include rapid tunability of the pass band over a wide wavelength range and high transmission efficiency. The TBFS is based on a unique integration of two pairs of broadband Raman reflection holographic filters with two rotating spherical lenses. In experiments, a prototype of the TBFS was shown to be capable of spectral sampling of images in the visible range over a 200-nm spectral range with a spectral resolution of .30 nm. The figure depicts the optical layout of a prototype of the TBFS as part of a laboratory multispectral imaging system for the spectral sampling of color test images in two orthogonal polarizations. Each pair of broadband Raman reflection holographic filters is mounted at an equatorial plane between two halves of a spherical lens. The two filters in each pair are characterized by steep spectral slopes (equivalently, narrow spectral edges), no ripple or side lobes in their pass bands, and a few nanometers of non-overlapping wavelength range between their pass bands. Each spherical lens and thus the filter pair within it is rotated in order to rapidly tune its pass band. The rotations of the lenses are effected by electronically controlled, programmable, high-precision rotation stages. The rotations are coordinated by electronic circuits operating under overall supervision of a personal computer in order to obtain the desired variation of the overall pass bands with time. Embedding the filters inside the spherical lenses increases the range of the hologram incidence angles, making it possible to continuously tune the pass and stop bands of the filters over a wider wavelength range. In addition, each spherical lens also serves as part of the imaging optics: The telephoto lens focuses

  11. Tunable-Bandwidth Filter System

    NASA Technical Reports Server (NTRS)

    Bailey, John W.

    2004-01-01

    A tunable-bandwidth filter system (TBFS), now undergoing development, is intended to be part of a remote sensing multispectral imaging system that will operate in the visible and near infrared spectral region (wavelengths from 400 to 900 nm). Attributes of the TBFS include rapid tunability of the pass band over a wide wavelength range and high transmission efficiency. The TBFS is based on a unique integration of two pairs of broadband Raman reflection holographic filters with two rotating spherical lenses. In experiments, a prototype of the TBFS, was shown to be capable of spectral sampling of images in the visible range over a 200 nm spectral range with a spectral resolution of 30 nm. The figure depicts the optical layout of a prototype of the TBFS as part of a laboratory multispectral imaging system for the spectral sampling of color test images in two orthogonal polarizations. Each pair of broadband Raman reflection holographic filters is mounted at an equatorial plane between two halves of a spherical lens. The two filters in each pair are characterized by steep spectral slopes (equivalently, narrow spectral edges), no ripple or side lobes in their pass bands, and a few nanometers of non-overlapping wavelength range between their pass bands. Each spherical lens and thus the filter pair within it is rotated in order to rapidly tune its pass band. The rotations of are effected by electronically controlled, programmable, high-precision rotation stages. The rotations are coordinated by electronic circuits operating under overall supervision of a personal computer in order to obtain the desired variation of the overall pass bands with time. Embedding the filters inside the spherical lenses increases the range of the hologram incidence angles, making it possible to continuously tune the pass and stop bands of the filters over a wider wavelength range. In addition, each spherical lens also serves as part of the imaging optics: The telephoto lens focuses incoming light

  12. Acquisition of Competencies by Medical Students in Neurological Emergency Simulation Environments Using High Fidelity Patient Simulators.

    PubMed

    Sánchez-Ledesma, M J; Juanes, J A; Sáncho, C; Alonso-Sardón, M; Gonçalves, J

    2016-06-01

    The training of medical students demands practice of skills in scenarios as close as possible to real ones that on one hand ensure acquisition of competencies, and on the other, avoid putting patients at risk. This study shows the practicality of using high definition mannequins (SimMan 3G) in scenarios of first attention in neurological emergencies so that medical students at the Faculty of Medicine of the University of Salamanca could acquire specific and transversal competencies. The repetition of activities in simulation environments significantly facilitates the acquisition of competencies by groups of students (p < 00.5). The greatest achievements refer to skills whereas the competencies that demand greater integration of knowledge seem to need more time or new sessions. This is what happens with the competencies related to the initial diagnosis, the requesting of tests and therapeutic approaches, which demand greater theoretical knowledge. PMID:27106583

  13. A Unix SVR-4-OS9 distributed data acquisition for high energy physics

    SciTech Connect

    Drouhin, F.; Schwaller, B.; Fontaine, J.C.; Charles, F.; Pallares, A.; Huss, D.

    1998-08-01

    The distributed data acquisition (DAQ) system developed by the GRPHE (Groupe de Recherche en Physique des Hautes Energies) group is a combination of hardware and software dedicated to high energy physics. The system described here is used in the beam tests of the CMs tracker. The central processor of the system is a RISC CPU hosted in a VME card, running a POSIX compliant UNIX system. Specialized real-time OS9 VME cards perform the instrumentation control. The main data flow goes over a deterministic high speed network. The Unix system manages a list of OS9 front-end systems with a synchronization protocol running over a TCP/IP layer.

  14. Bandwidth extension for IR detectors through spatial-frequency shifting.

    PubMed

    Lettington, A H; Hong, Q H; Tzimopoulou, S

    1996-09-10

    We describe a new scheme for extending the bandwidth of IR detectors by the employment of a reticle that shifts the higher spatial-frequency content of the scene onto the lower-frequency region. Then all the spatial-frequency information can pass through the bandwidth of the detector system, so that a high-resolution image may be reconstructed from a series of pictures obtained with the reticle in a number of predetermined positions. PMID:21127517

  15. Data acquisition and control system for the High-Level Waste Tank Farm at Hanford, Washington

    SciTech Connect

    Hoida, H.W.; Hatcher, C.R.; Trujillo, L.T.; Holt, D.H.; Vargo, G.F.; Martin, J.; Stastny, G.; Echave, R.; Eldridge, K.

    1993-08-01

    The High-Level Nuclear Waste Storage Tank 241-SY-101 periodically releases flammable gasses. Mitigation experiments to release the gasses continuously to avoid a catastrophic build-up are planned for FY93 and beyond. Los Alamos has provided a data acquisition and control system (DACS) to monitor and control mitigation experiments on SY-101. The DACS consists of a data acquisition trailer to house the electronic components and computers in a friendly environment, a computer system running process control software for monitoring and controlling the tests, signal conditioners to convert the instrument signals to a usable form for the DACS, programmable logic controllers to process sensor signals and take action quickly, a fast data acquisition system for recording transient data, and a remote monitoring system to monitor the progress of the experiment. Equipment to monitor the release of the gasses was also provided. The first experiment involves a mixer pump to mix the waste and allow the gasses to be released at the surface of the liquid as the gas is being formed. The initial tests are scheduled for July 1993.

  16. High Speed Data Acquisition System for Three-Dimensional X-Ray and Neutron Computed Tomography

    SciTech Connect

    Davis, A.W.; Claytor, T.N.; Sheats, M.J.

    1999-07-01

    Computed tomography for nondestructive evaluation applications has been limited by system cost, resolution, and time requirements for three-dimensional data sets. FlashCT (Flat panel Amorphous Silicon High-Resolution Computed Tomography) is a system developed at Los Alamos National Laboratory to address these three problems. Developed around a flat panel amorphous silicon detector array, FlashCT is suitable for low to medium energy x-ray and neutron computed tomography at 127-micron resolution. Overall system size is small, allowing rapid transportation to a variety of radiographic sources. System control software was developed in LabVIEW for Windows NT to allow multithreading of data acquisition, data correction, and staging motor control. The system control software simplifies data collection and allows fully automated control of the data acquisition process, leading toward remote or unattended operation. The first generation of the FlashCT Data Acquisition System was completed in Au gust 1998, and since that time the system has been tested using x-ray sources ranging in energy from 60 kV to 20MV. The system has also been used to collect data for thermal neutron computed tomography at Los Alamos Neutron Science Center (LANSCE). System improvements have been proposed to provide faster data collection and greater dynamic range during data collection.

  17. High-throughput hyperpolarized 13C metabolic investigations using a multi-channel acquisition system

    NASA Astrophysics Data System (ADS)

    Lee, Jaehyuk; Ramirez, Marc S.; Walker, Christopher M.; Chen, Yunyun; Yi, Stacey; Sandulache, Vlad C.; Lai, Stephen Y.; Bankson, James A.

    2015-11-01

    Magnetic resonance imaging and spectroscopy of hyperpolarized (HP) compounds such as [1-13C]-pyruvate have shown tremendous potential for offering new insight into disease and response to therapy. New applications of this technology in clinical research and care will require extensive validation in cells and animal models, a process that may be limited by the high cost and modest throughput associated with dynamic nuclear polarization. Relatively wide spectral separation between [1-13C]-pyruvate and its chemical endpoints in vivo are conducive to simultaneous multi-sample measurements, even in the presence of a suboptimal global shim. Multi-channel acquisitions could conserve costs and accelerate experiments by allowing acquisition from multiple independent samples following a single dissolution. Unfortunately, many existing preclinical MRI systems are equipped with only a single channel for broadband acquisitions. In this work, we examine the feasibility of this concept using a broadband multi-channel digital receiver extension and detector arrays that allow concurrent measurement of dynamic spectroscopic data from ex vivo enzyme phantoms, in vitro anaplastic thyroid carcinoma cells, and in vivo in tumor-bearing mice. Throughput and the cost of consumables were improved by up to a factor of four. These preliminary results demonstrate the potential for efficient multi-sample studies employing hyperpolarized agents.

  18. Application of accelerated acquisition and highly constrained reconstruction methods to MR

    NASA Astrophysics Data System (ADS)

    Wang, Kang

    2011-12-01

    There are many Magnetic Resonance Imaging (MRI) applications that require rapid data acquisition. In conventional proton MRI, representative applications include real-time dynamic imaging, whole-chest pulmonary perfusion imaging, high resolution coronary imaging, MR T1 or T2 mapping, etc. The requirement for fast acquisition and novel reconstruction methods is either due to clinical demand for high temporal resolution, high spatial resolution, or both. Another important category in which fast MRI methods are highly desirable is imaging with hyperpolarized (HP) contrast media, such as HP 3He imaging for evaluation of pulmonary function, and imaging of HP 13C-labeled substrates for the study of in vivo metabolic processes. To address these needs, numerous MR undersampling methods have been developed and combined with novel image reconstruction techniques. This thesis aims to develop novel data acquisition and image reconstruction techniques for the following applications. (I) Ultrashort echo time spectroscopic imaging (UTESI). The need for acquiring many echo images in spectroscopic imaging with high spatial resolution usually results in extended scan times, and thus requires k-space undersampling and novel imaging reconstruction methods to overcome the artifacts related to the undersampling. (2) Dynamic hyperpolarized 13C spectroscopic imaging. HP 13C compounds exhibit non-equilibrium T1 decay and rapidly evolving spectral dynamics, and therefore it is vital to utilize the polarized signal wisely and efficiently to observe the entire temporal dynamic of the injected "C compounds as well as the corresponding downstream metabolites. (3) Time-resolved contrast-enhanced MR angiography. The diagnosis of vascular diseases often requires large coverage of human body anatomies with high spatial resolution and sufficient temporal resolution for the separation of arterial phases from venous phases. The goal of simultaneously achieving high spatial and temporal resolution has

  19. Algorithms and Requirements for Measuring Network Bandwidth

    SciTech Connect

    Jin, Guojun

    2002-12-08

    This report unveils new algorithms for actively measuring (not estimating) available bandwidths with very low intrusion, computing cross traffic, thus estimating the physical bandwidth, provides mathematical proof that the algorithms are accurate, and addresses conditions, requirements, and limitations for new and existing algorithms for measuring network bandwidths. The paper also discusses a number of important terminologies and issues for network bandwidth measurement, and introduces a fundamental parameter -Maximum Burst Size that is critical for implementing algorithms based on multiple packets.

  20. Improving the Bandwidth Selection in Kernel Equating

    ERIC Educational Resources Information Center

    Andersson, Björn; von Davier, Alina A.

    2014-01-01

    We investigate the current bandwidth selection methods in kernel equating and propose a method based on Silverman's rule of thumb for selecting the bandwidth parameters. In kernel equating, the bandwidth parameters have previously been obtained by minimizing a penalty function. This minimization process has been criticized by practitioners…

  1. Fuzzy-based adaptive bandwidth control for loss guarantees.

    PubMed

    Siripongwutikorn, Peerapon; Banerjee, Sujata; Tipper, David

    2005-09-01

    This paper presents the use of adaptive bandwidth control (ABC) for a quantitative packet loss rate guarantee to aggregate traffic in packet switched networks. ABC starts with some initial amount of bandwidth allocated to a queue and adjusts it over time based on online measurements of system states to ensure that the allocated bandwidth is just enough to attain the specified loss requirement. Consequently, no a priori detailed traffic information is required, making ABC more suitable for efficient aggregate quality of service (QoS) provisioning. We propose an ABC algorithm called augmented Fuzzy (A-Fuzzy) control, whereby fuzzy logic control is used to keep an average queue length at an appropriate target value, and the measured packet loss rate is used to augment the standard control to achieve better performance. An extensive simulation study based on both theoretical traffic models and real traffic traces under a wide range of system configurations demonstrates that the A-Fuzzy control itself is highly robust, yields high bandwidth utilization, and is indeed a viable alternative and improvement to static bandwidth allocation (SBA) and existing adaptive bandwidth allocation schemes. Additionally, we develop a simple and efficient measurement-based admission control procedure which limits the amount of input traffic in order to maintain the performance of the A-Fuzzy control at an acceptable level.

  2. The simulation of a data acquisition system for a proposed high resolution PET scanner

    SciTech Connect

    Rotolo, C.; Larwill, M.; Chappa, S.; Ordonez, C.

    1993-10-01

    The simulation of a specific data acquisition (DAQ) system architecture for a proposed high resolution Positron Emission Tomography (PET) scanner is discussed. Stochastic processes are used extensively to model PET scanner signal timing and probable DAQ circuit limitations. Certain architectural parameters, along with stochastic parameters, are varied to quantatively study the resulting output under various conditions. The inclusion of the DAQ in the model represents a novel method of more complete simulations of tomograph designs, and could prove to be of pivotal importance in the optimization of such designs.

  3. Development of a Real-Time, High-Speed Distribution Level Data Acquisition System

    SciTech Connect

    Bank, J.; Kroposki, B.

    2012-01-01

    With the development of smart grids and the deployment of their enabling technologies, improved data acquisition will be needed at the distribution level to understand the full impact of these changes. With this in mind, NREL has developed a high-speed measurement and data collection network targeted specifically at the distribution level. This network is based around adaptable, rugged measurement devices designed for deployment at a variety of low and medium voltage locations below the sub-station. Each of these devices is capable of real-time data transmission via an Internet connection. Additionally, several analysis and visualization applications have been developed around the incoming data streams.

  4. Parallel pulse processing and data acquisition for high speed, low error flow cytometry

    DOEpatents

    Engh, G.J. van den; Stokdijk, W.

    1992-09-22

    A digitally synchronized parallel pulse processing and data acquisition system for a flow cytometer has multiple parallel input channels with independent pulse digitization and FIFO storage buffer. A trigger circuit controls the pulse digitization on all channels. After an event has been stored in each FIFO, a bus controller moves the oldest entry from each FIFO buffer onto a common data bus. The trigger circuit generates an ID number for each FIFO entry, which is checked by an error detection circuit. The system has high speed and low error rate. 17 figs.

  5. Parallel pulse processing and data acquisition for high speed, low error flow cytometry

    DOEpatents

    van den Engh, Gerrit J.; Stokdijk, Willem

    1992-01-01

    A digitally synchronized parallel pulse processing and data acquisition system for a flow cytometer has multiple parallel input channels with independent pulse digitization and FIFO storage buffer. A trigger circuit controls the pulse digitization on all channels. After an event has been stored in each FIFO, a bus controller moves the oldest entry from each FIFO buffer onto a common data bus. The trigger circuit generates an ID number for each FIFO entry, which is checked by an error detection circuit. The system has high speed and low error rate.

  6. Effect of bandwidth knowledge of results on the learning of a grip force control task.

    PubMed

    Ugrinowitsch, Herbert; Ugrinowitsch, Alessandra Aguilar Coca; Benda, Rodolfo Novellino; Tertuliano, Ivan Wallan

    2010-12-01

    An experiment was conducted to investigate the persistence of the effect of "bandwidth knowledge of results (KR)" manipulated during the learning phase of performing a manual force-control task. The experiment consisted of two phases, an acquisition phase with the goal of maintaining 60% maximum force in 30 trials, and a second phase with the objective of maintaining 40% of maximum force in 20 further trials. There were four bandwidths of KR: when performance error exceeded 5, 10, or 15% of the target, and a control group (0% bandwidth). Analysis showed that 5, 10, and 15% bandwidth led to better performance than 0% bandwidth KR at the beginning of the second phase and persisted during the extended trials.

  7. An intelligent tutoring system for the investigation of high performance skill acquisition

    NASA Technical Reports Server (NTRS)

    Fink, Pamela K.; Herren, L. Tandy; Regian, J. Wesley

    1991-01-01

    The issue of training high performance skills is of increasing concern. These skills include tasks such as driving a car, playing the piano, and flying an aircraft. Traditionally, the training of high performance skills has been accomplished through the use of expensive, high-fidelity, 3-D simulators, and/or on-the-job training using the actual equipment. Such an approach to training is quite expensive. The design, implementation, and deployment of an intelligent tutoring system developed for the purpose of studying the effectiveness of skill acquisition using lower-cost, lower-physical-fidelity, 2-D simulation. Preliminary experimental results are quite encouraging, indicating that intelligent tutoring systems are a cost-effective means of training high performance skills.

  8. Accounting for filter bandwidth improves the quantitative accuracy of bioluminescence tomography.

    PubMed

    Taylor, Shelley L; Mason, Suzannah K G; Glinton, Sophie L; Cobbold, Mark; Dehghani, Hamid

    2015-09-01

    Bioluminescence imaging is a noninvasive technique whereby surface weighted images of luminescent probes within animals are used to characterize cell count and function. Traditionally, data are collected over the entire emission spectrum of the source using no filters and are used to evaluate cell count/function over the entire spectrum. Alternatively, multispectral data over several wavelengths can be incorporated to perform tomographic reconstruction of source location and intensity. However, bandpass filters used for multispectral data acquisition have a specific bandwidth, which is ignored in the reconstruction. In this work, ignoring the bandwidth is shown to introduce a dependence of the recovered source intensity on the bandwidth of the filters. A method of accounting for the bandwidth of filters used during multispectral data acquisition is presented and its efficacy in increasing the quantitative accuracy of bioluminescence tomography is demonstrated through simulation and experiment. It is demonstrated that while using filters with a large bandwidth can dramatically decrease the data acquisition time, if not accounted for, errors of up to 200% in quantitative accuracy are introduced in two-dimensional planar imaging, even after normalization. For tomographic imaging, the use of this method to account for filter bandwidth dramatically improves the quantitative accuracy. PMID:26325264

  9. Accounting for filter bandwidth improves the quantitative accuracy of bioluminescence tomography

    NASA Astrophysics Data System (ADS)

    Taylor, Shelley L.; Mason, Suzannah K. G.; Glinton, Sophie L.; Cobbold, Mark; Dehghani, Hamid

    2015-09-01

    Bioluminescence imaging is a noninvasive technique whereby surface weighted images of luminescent probes within animals are used to characterize cell count and function. Traditionally, data are collected over the entire emission spectrum of the source using no filters and are used to evaluate cell count/function over the entire spectrum. Alternatively, multispectral data over several wavelengths can be incorporated to perform tomographic reconstruction of source location and intensity. However, bandpass filters used for multispectral data acquisition have a specific bandwidth, which is ignored in the reconstruction. In this work, ignoring the bandwidth is shown to introduce a dependence of the recovered source intensity on the bandwidth of the filters. A method of accounting for the bandwidth of filters used during multispectral data acquisition is presented and its efficacy in increasing the quantitative accuracy of bioluminescence tomography is demonstrated through simulation and experiment. It is demonstrated that while using filters with a large bandwidth can dramatically decrease the data acquisition time, if not accounted for, errors of up to 200% in quantitative accuracy are introduced in two-dimensional planar imaging, even after normalization. For tomographic imaging, the use of this method to account for filter bandwidth dramatically improves the quantitative accuracy.

  10. Xenon Acquisition Strategies for High-Power Electric Propulsion NASA Missions

    NASA Technical Reports Server (NTRS)

    Herman, Daniel A.; Unfried, Kenneth G.

    2015-01-01

    The benefits of high-power solar electric propulsion (SEP) for both NASA's human and science exploration missions combined with the technology investment from the Space Technology Mission Directorate have enabled the development of a 50kW-class SEP mission. NASA mission concepts developed, including the Asteroid Redirect Robotic Mission, and those proposed by contracted efforts for the 30kW-class demonstration have a range of xenon propellant loads from 100's of kg up to 10,000 kg. A xenon propellant load of 10 metric tons represents greater than 10% of the global annual production rate of xenon. A single procurement of this size with short-term delivery can disrupt the xenon market, driving up pricing, making the propellant costs for the mission prohibitive. This paper examines the status of the xenon industry worldwide, including historical xenon supply and pricing. The paper discusses approaches for acquiring on the order of 10 MT of xenon propellant considering realistic programmatic constraints to support potential near-term NASA missions. Finally, the paper will discuss acquisitions strategies for mission campaigns utilizing multiple high-power solar electric propulsion vehicles requiring 100's of metric tons of xenon over an extended period of time where a longer term acquisition approach could be implemented.

  11. Motion-blurred star acquisition method of the star tracker under high dynamic conditions.

    PubMed

    Sun, Ting; Xing, Fei; You, Zheng; Wei, Minsong

    2013-08-26

    The star tracker is one of the most promising attitude measurement devices used in spacecraft due to its extremely high accuracy. However, high dynamic performance is still one of its constraints. Smearing appears, making it more difficult to distinguish the energy dispersive star point from the noise. An effective star acquisition approach for motion-blurred star image is proposed in this work. The correlation filter and mathematical morphology algorithm is combined to enhance the signal energy and evaluate slowly varying background noise. The star point can be separated from most types of noise in this manner, making extraction and recognition easier. Partial image differentiation is then utilized to obtain the motion parameters from only one image of the star tracker based on the above process. Considering the motion model, the reference window is adopted to perform centroid determination. Star acquisition results of real on-orbit star images and laboratory validation experiments demonstrate that the method described in this work is effective and the dynamic performance of the star tracker could be improved along with more identified stars and guaranteed position accuracy of the star point.

  12. Use of a new high-speed digital data acquisition system in airborne ice-sounding

    USGS Publications Warehouse

    Wright, David L.; Bradley, Jerry A.; Hodge, Steven M.

    1989-01-01

    A high-speed digital data acquisition and signal averaging system for borehole, surface, and airborne radio-frequency geophysical measurements was designed and built by the US Geological Survey. The system permits signal averaging at rates high enough to achieve significant signal-to-noise enhancement in profiling, even in airborne applications. The first field use of the system took place in Greenland in 1987 for recording data on a 150 by 150-km grid centered on the summit of the Greenland ice sheet. About 6000-line km were flown and recorded using the new system. The data can be used to aid in siting a proposed scientific corehole through the ice sheet.

  13. Electro-optic dual-comb interferometry over 40  nm bandwidth.

    PubMed

    Durán, Vicente; Andrekson, Peter A; Torres-Company, Víctor

    2016-09-15

    Dual-comb interferometry is a measurement technique that uses two laser frequency combs to retrieve complex spectra in a line-by-line basis. This technique can be implemented with electro-optic frequency combs, offering intrinsic mutual coherence, high acquisition speed and flexible repetition-rate operation. A challenge with the operation of this kind of frequency comb in dual-comb interferometry is its limited optical bandwidth. Here, we use coherent spectral broadening and demonstrate electro-optic dual-comb interferometry over the entire telecommunications C band (200 lines covering ∼40  nm, measured within 10 μs at 100 signal-to-noise ratio per spectral line). These results offer new prospects for electro-optic dual-comb interferometry as a suitable technology for high-speed broadband metrology, for example in optical coherence tomography or coherent Raman microscopy.

  14. Electro-optic dual-comb interferometry over 40  nm bandwidth.

    PubMed

    Durán, Vicente; Andrekson, Peter A; Torres-Company, Víctor

    2016-09-15

    Dual-comb interferometry is a measurement technique that uses two laser frequency combs to retrieve complex spectra in a line-by-line basis. This technique can be implemented with electro-optic frequency combs, offering intrinsic mutual coherence, high acquisition speed and flexible repetition-rate operation. A challenge with the operation of this kind of frequency comb in dual-comb interferometry is its limited optical bandwidth. Here, we use coherent spectral broadening and demonstrate electro-optic dual-comb interferometry over the entire telecommunications C band (200 lines covering ∼40  nm, measured within 10 μs at 100 signal-to-noise ratio per spectral line). These results offer new prospects for electro-optic dual-comb interferometry as a suitable technology for high-speed broadband metrology, for example in optical coherence tomography or coherent Raman microscopy. PMID:27628354

  15. Electro-optic dual-comb interferometry over 40 nm bandwidth

    NASA Astrophysics Data System (ADS)

    Durán, Vicente; Andrekson, Peter A.; Torres-Company, Víctor

    2016-09-01

    Dual-comb interferometry is a measurement technique that uses two laser frequency combs to retrieve complex spectra in a line-by-line basis. This technique can be implemented with electro-optic frequency combs, offering intrinsic mutual coherence, high acquisition speed and flexible repetition-rate operation. A challenge with the operation of this kind of frequency comb in dual-comb interferometry is its limited optical bandwidth. Here, we use coherent spectral broadening and demonstrate electro-optic dual-comb interferometry over the entire telecommunications C band (200 lines covering ~ 40 nm, measured within 10 microseconds at 100 signal-to-noise ratio per spectral line). These results offer new prospects for electro-optic dual-comb interferometry as a suitable technology for high-speed broadband metrology, for example in optical coherence tomography or coherent Raman microscopy.

  16. Inertial Sensor Assisted Acquisition, Tracking, and Pointing for High Data Rate Free Space Optical Communications

    NASA Technical Reports Server (NTRS)

    Lee, Shinhak; Ortiz, Gerry G.

    2003-01-01

    We discuss use of inertial sensors to facilitate deep space optical communications. Implementation of this concept requires accurate and wide bandwidth inertial sensors. In this presentation, the principal concept and algorithm using linear accelerometers will be given along with the simulation and experimental results.

  17. On the spatial bandwidth of scattered fields

    NASA Astrophysics Data System (ADS)

    Bucci, Ovidio M.; Franceschetti, Giorgio

    1987-12-01

    The concept of spatial bandwidth of scattered electromagnetic fields is introduced. It is shown that the scattered fields are almost space-bandlimited functions. The effective bandwidth W is introduced and evaluated for a very general scattering system, as well as the error made using functions bandlimited to values greater than the effective bandwidth (w greater than W) for representing the scattered field. The effective bandwidth is very simply related to the maximum dimension of the scattering system; the error drops to negligible values for modest increases of w compared to W, in the case of large scatterers. Consequences of these general results are stressed.

  18. A new bandwidth compression system of picture signals - The TAT

    NASA Astrophysics Data System (ADS)

    Tanimoto, M.; Chiba, N.; Yasui, H.; Murakami, M.

    A new bandwidth compression system of picture signals called the Time-Axis Transform (TAT) system is presented. It can be applied to the various fields of transmission and recording of picture signals such as the satellite broadcast of high-definition televison. The TAT compresses the bandwidth by reducing the number of transmitted pixels. The transmitted pixels consist of two kinds of pixels: the basic pixels and the additional pixels. The location of the former is fixed and that of the latter varies from picture to picture to minimize the interpolation error in the reconstructed picture. It compresses the bandwidth of the picture signal to one half or less, keeping high picture quality. Both the average power and the peak value of the distortion due to the interpolation error of the deleted pixels are greatly improved.

  19. Analytical and flight investigation of the influence of rotor and other high-order dynamics on helicopter flight-control system bandwidth

    NASA Technical Reports Server (NTRS)

    Chen, R. T. N.; Hindson, W. S.

    1985-01-01

    The increasing use of highly augmented digital flight-control systems in modern military helicopters prompted an examination of the influence of rotor dynamics and other high-order dynamics on control-system performance. A study was conducted at NASA Ames Research Center to correlate theoretical predictions of feedback gain limits in the roll axis with experimental test data obtained from a variable-stability research helicopter. Feedback gains, the break frequency of the presampling sensor filter, and the computational frame time of the flight computer were systematically varied. The results, which showed excellent theoretical and experimental correlation, indicate that the rotor-dynamics, sensor-filter, and digital-data processing delays can severely limit the usable values of the roll-rate and roll-attitude feedback gains.

  20. Highly effective contraception and acquisition of HIV and other sexually transmitted infections.

    PubMed

    Morrison, Charles S; Turner, Abigail Norris; Jones, LaShawn B

    2009-04-01

    A key question for clinicians is whether an aetiological association exists between highly effective contraceptive methods and women's risk of acquiring sexually transmitted infections (STIs), including human immunodeficiency virus (HIV). The authors searched the peer-reviewed literature for prospective studies published from January 1966 to August 2008 that assessed contraception and STI/HIV risk. The focus was on combined oral contraceptives (OCs), depot-medroxyprogesterone acetate (DMPA), the T380a copper intra-uterine device (IUD) and the risk of infection with HIV, Chlamydia trachomatis and Neisseria gonorrhoeae. Current data suggest that neither OCs nor DMPA increase HIV risk among women in the general population. Data are equivocal for women in high-risk groups (e.g. sex workers). Current data suggest an increased risk of chlamydial infection associated with OC use, with weaker evidence supporting a harmful effect of DMPA. Reports of OCs and gonococcal infection are inconsistent, and DMPA does not appear to be associated with gonorrhoea acquisition. Data suggest no increased STI/HIV risk among copper IUD users. Prospective data on highly effective contraceptive methods and women's STI/HIV risk are limited, and many studies have important methodological weaknesses. Additional information about the STI/HIV risks associated with these highly effective contraceptive methods is needed.

  1. Highly sensitive wide bandwidth photodetector based on internal photoemission in CVD grown p-type MoS2/graphene Schottky junction.

    PubMed

    Vabbina, PhaniKiran; Choudhary, Nitin; Chowdhury, Al-Amin; Sinha, Raju; Karabiyik, Mustafa; Das, Santanu; Choi, Wonbong; Pala, Nezih

    2015-07-22

    Two dimensional (2D) Molybdenum disulfide (MoS2) has evolved as a promising material for next generation optoelectronic devices owing to its unique electrical and optical properties, such as band gap modulation, high optical absorption, and increased luminescence quantum yield. The 2D MoS2 photodetectors reported in the literature have presented low responsivity compared to silicon based photodetectors. In this study, we assembled atomically thin p-type MoS2 with graphene to form a MoS2/graphene Schottky photodetector where photo generated holes travel from graphene to MoS2 over the Schottky barrier under illumination. We found that the p-type MoS2 forms a Schottky junction with graphene with a barrier height of 139 meV, which results in high photocurrent and wide spectral range of detection with wavelength selectivity. The fabricated photodetector showed excellent photosensitivity with a maximum photo responsivity of 1.26 AW(-1) and a noise equivalent power of 7.8 × 10(-12) W/√Hz at 1440 nm.

  2. A Formative Study Investigating the Acquisition of Early Reading Skills among High School English Language Learners Beginning to Read English

    ERIC Educational Resources Information Center

    Bell, Athene Cooper

    2012-01-01

    A formative design experiment methodology was employed to investigate the acquisition of early reading skills for high school English language learners (ELLs) beginning to read English. A fundamental challenge facing high school ELLs entering schools in the United States for the first time is learning how to read. While there is considerable…

  3. Enhancing bandwidth of Josephson parametric amplifiers with impedance engineering

    NASA Astrophysics Data System (ADS)

    Roy, Tanay; A M, Vadiraj; Kundu, Suman; Patankar, Meghan; Vijayaraghavan, Rajamani

    2015-03-01

    Josephson parametric amplifiers (JPAs) are a crucial component of superconducting quantum information processing systems since they enable fast, high-fidelity measurement of qubits. However, JPAs based on a single SQUID oscillator suffer from two major drawbacks - narrow bandwidth and gain saturation at low signal powers, and are typically suited to single qubit experiments only. With the rapid development of multi-qubit systems, there is a practical need to develop an amplifier with larger bandwidth and signal handling capacity, while maintaining gain and noise performance. We will describe a new method to enhance the bandwidth by introducing a frequency dependent shunting impedance for the JPA. To prevent gain saturation, we also replace the single SQUID with a SQUID array. With an appropriate choice of device parameters, numerical calculations indicate the possibility of obtaining 20 dB gain with 700 MHz of bandwidth and near quantum limited noise performance. We will present experimental results demonstrating bandwidth enhancement and discuss strategies for optimizing overall amplifier performance.

  4. Bandwidth Efficient Wireless Digital Modem Developed

    NASA Technical Reports Server (NTRS)

    Kifle, Muli

    1999-01-01

    NASA Lewis Research Center has developed a digital approach for broadcasting highfidelity audio (nearly compact disk (CD) quality sound) in the commercial frequencymodulated (FM) broadcast band. This digital approach provides a means of achieving high data transmission rates with low hardware complexity--including low mass, size, and power consumption. Lewis has completed the design and prototype development of a bandwidth-efficient digital modem (modulator and demodulator) that uses a spectrally efficient modulation scheme: 16-ary rectangular quadrature amplitude modulation, or 16- ary QAM. The digital implementation is based strictly on inexpensive, commercial off-theshelf digital signal processing (DSP) hardware to perform up and down conversions and pulse shaping. The digital modem transmits data at rates up to 76 kilobits per second (kbps), which is almost 3 times faster than standard 28.8-kbps telephone modems. In addition, the modem offers improved power and spectral performance, flexible operation, and low-cost implementation.

  5. Contrast-enhanced MR Angiography of the Abdomen with Highly Accelerated Acquisition Techniques

    PubMed Central

    Mostardi, Petrice M.; Glockner, James F.; Young, Phillip M.

    2011-01-01

    Purpose: To demonstrate that highly accelerated (net acceleration factor [Rnet] ≥ 10) acquisition techniques can be used to generate three-dimensional (3D) subsecond timing images, as well as diagnostic-quality high-spatial-resolution contrast material–enhanced (CE) renal magnetic resonance (MR) angiograms with a single split dose of contrast material. Materials and Methods: All studies were approved by the institutional review board and were HIPAA compliant; written consent was obtained from all participants. Twenty-two studies were performed in 10 female volunteers (average age, 47 years; range, 27–62 years) and six patients with renovascular disease (three women; average age, 48 years; range, 37–68 years; three men; average age, 60 years; range, 50–67 years; composite average age, 54 years; range, 38–68 years). The two-part protocol consisted of a low-dose (2 mL contrast material) 3D timing image with approximate 1-second frame time, followed by a high-spatial-resolution (1.0–1.6-mm isotropic voxels) breath-hold 3D renal MR angiogram (18 mL) over the full abdominal field of view. Both acquisitions used two-dimensional (2D) sensitivity encoding acceleration factor (R) of eight and 2D homodyne (HD) acceleration (RHD) of 1.4–1.8 for Rnet = R · RHD of 10 or higher. Statistical analysis included determination of mean values and standard deviations of image quality scores performed by two experienced reviewers with use of eight evaluation criteria. Results: The 2-mL 3D time-resolved image successfully portrayed progressive arterial filling in all 22 studies and provided an anatomic overview of the vasculature. Successful timing was also demonstrated in that the renal MR angiogram showed adequate or excellent portrayal of the main renal arteries in 21 of 22 studies. Conclusion: Two-dimensional acceleration techniques with Rnet of 10 or higher can be used in CE MR angiography to acquire (a) a 3D image series with 1-second frame time, allowing accurate

  6. Wire-grid polarizer using galvanic growth technology: demonstration of a wide spectral and angular bandwidth component with high extinction ratio

    NASA Astrophysics Data System (ADS)

    Verrier, Isabelle; Kämpfe, Thomas; Celle, Frederic; Cazier, Anthony; Guttmann, Markus; Matthis, Barbara; Laukkanen, Janne; Lacour, Frédéric; Veillas, Colette; Reynaud, Stéphanie; Parriaux, Olivier; Jourlin, Yves

    2015-04-01

    Functional demonstration of a wide band, wide angular width wire-grid polarizer has been made in the framework of a user project of the European project ACTMOST (Access To Micro-Optics Expertise, Services and Technologies). The polarization function relies on linear polarizers using the wire-grid polarizer principle by means of a metal grating of unusually large period, exhibiting a large extinction of the transmission of the TE polarization in the 850-nm wavelength range. This grating achieves a broadband and especially high angular aperture reflection with low loss and permits resorting to very low cost incoherent light sources for the transmitted TM polarization. This paper will describe the design, the modeling and optimization, as well as the complete technological process chain, that has been used, starting with the photoresist grating printing using phase-mask UV-based lithography to the uniform galvanic growth of a very shallow gold grating on transparent conductive layer deposited on a glass substrate. Transmission curves for both polarizations performed on the first demonstrators will be presented.

  7. Monitoring of HTS compound library quality via a high-resolution image acquisition and processing instrument.

    PubMed

    Baillargeon, Pierre; Scampavia, Louis; Einsteder, Ross; Hodder, Peter

    2011-06-01

    This report presents the high-resolution image acquisition and processing instrument for compound management applications (HIAPI-CM). The HIAPI-CM combines imaging spectroscopy and machine-vision analysis to perform rapid assessment of high-throughput screening (HTS) compound library quality. It has been customized to detect and classify typical artifacts found in HTS compound library microtiter plates (MTPs). These artifacts include (1) insufficient volume of liquid compound sample, (2) compound precipitation, and (3) colored compounds that interfere with HTS assay detection format readout. The HIAPI-CM is also configured to automatically query and compare its analysis results to data stored in a LIMS or corporate database, aiding in the detection of compound registration errors. To demonstrate its capabilities, several compound plates (n=5760 wells total) containing different artifacts were measured via automated HIAPI-CM analysis, and results compared with those obtained by manual (visual) inspection. In all cases, the instrument demonstrated high fidelity (99.8% empty wells; 100.1% filled wells; 94.4% for partially filled wells; 94.0% for wells containing colored compounds), and in the case of precipitate detection, the HIAPI-CM results significantly exceeded the fidelity of visual observations (220.0%). As described, the HIAPI-CM allows for noninvasive, nondestructive MTP assessment with a diagnostic throughput of about 1min per plate, reducing analytical expenses and improving the quality and stewardship of HTS compound libraries.

  8. 47 CFR 101.109 - Bandwidth.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Bandwidth. 101.109 Section 101.109 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Technical Standards § 101.109 Bandwidth. Link to an amendment published at 77 FR 54432, Sept....

  9. 47 CFR 101.109 - Bandwidth.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Bandwidth. 101.109 Section 101.109 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Technical Standards § 101.109 Bandwidth. (a) Each authorization issued pursuant to these...

  10. Directing Traffic: Managing Internet Bandwidth Fairly

    ERIC Educational Resources Information Center

    Paine, Thomas A.; Griggs, Tyler J.

    2008-01-01

    Educational institutions today face budgetary restraints and scarce resources, complicating the decision of how to allot bandwidth for campus network users. Additionally, campus concerns over peer-to-peer networking (specifically outbound Internet traffic) have increased because of bandwidth and copyright issues. In this article, the authors…

  11. Energy Bandwidth for Petroleum Refining Processes

    SciTech Connect

    none,

    2006-10-01

    The petroleum refining energy bandwidth report analyzes the most energy-intensive unit operations used in U.S. refineries: crude oil distillation, fluid catalytic cracking, catalytic hydrotreating, catalytic reforming, and alkylation. The "bandwidth" provides a snapshot of the energy losses that can potentially be recovered through best practices and technology R&D.

  12. Bandwidth enhancement of dielectric resonator antennas

    NASA Technical Reports Server (NTRS)

    Lee, Richard Q.; Simons, Rainee N.

    1993-01-01

    An experimental investigation of bandwidth enhancement of dielectric resonator antennas (DRA) using parasitic elements is reported. Substantial bandwidth enhancement for the HE(sub 11delta) mode of the stacked geometry and for the HE(sub 13delta) mode of the coplanar collinear geometry was demonstrated. Excellent radiation patterns for the HE(sub 11delta) mode were also recorded.

  13. P-Cable: New High-Resolution 3D Seismic Acquisition Technology

    NASA Astrophysics Data System (ADS)

    Planke, Sverre; Berndt, Christian; Mienert, Jürgen; Bünz, Stefan; Eriksen, Frode N.; Eriksen, Ola K.

    2010-05-01

    We have developed a new cost-efficient technology for acquisition of high-resolution 3D seismic data: the P-Cable system. This technology is very well suited for deep water exploration, site surveys, and studies of shallow gas and fluid migration associated with gas hydrates or leaking reservoirs. It delivers unparalleled 3D seismic images of subsurface sediment architectures. The P-Cable system consists of a seismic cable towed perpendicular to a vessel's steaming direction. This configuration allows us to image an up to 150 m wide swath of the sub-surface for each sail line. Conventional 3D seismic technology relies on several very long streamers (up to 10 km long streamers are common), large sources, and costly operations. In contrast, the P-Cable system is light-weight and fast to deploy from small vessels. Only a small source is required as the system is made for relatively shallow imaging, typically above the first water-bottom multiple. The P-Cable system is particularly useful for acquisition of small 3D cubes, 10-50 km2, in focus areas, rather than extensive mapping of large regions. The rapid deployment and recovery of the system makes it possible to acquire several small cubes (10 to 30 km2) with high-resolution (50-250 Hz) seismic data in during one cruise. The first development of the P-Cable system was a cooperative project achieved by Volcanic Basin Petroleum Research (VBPR), University of Tromsø, National Oceanography Centre, Southampton, and industry partners. Field trials using a 12-streamer system were conducted on sites with active fluid-leakage systems on the Norwegian-Barents-Svalbard margin, the Gulf of Cadiz, and the Mediterranean. The second phase of the development introduced digital streamers. The new P-Cable2 system also includes integrated tow and cross cables for power and data transmission and improved doors to spread the larger cross cable. This digital system has been successfully used during six cruises by the University of Troms

  14. A New High Channel-Count, High Scan-Rate, Data Acquisition System for the NASA Langley Transonic Dynamics Tunnel

    NASA Technical Reports Server (NTRS)

    Ivanco, Thomas G.; Sekula, Martin K.; Piatak, David J.; Simmons, Scott A.; Babel, Walter C.; Collins, Jesse G.; Ramey, James M.; Heald, Dean M.

    2016-01-01

    A data acquisition system upgrade project, known as AB-DAS, is underway at the NASA Langley Transonic Dynamics Tunnel. AB-DAS will soon serve as the primary data system and will substantially increase the scan-rate capabilities and analog channel count while maintaining other unique aeroelastic and dynamic test capabilities required of the facility. AB-DAS is configurable, adaptable, and enables buffet and aeroacoustic tests by synchronously scanning all analog channels and recording the high scan-rate time history values for each data quantity. AB-DAS is currently available for use as a stand-alone data system with limited capabilities while development continues. This paper describes AB-DAS, the design methodology, and the current features and capabilities. It also outlines the future work and projected capabilities following completion of the data system upgrade project.

  15. High spatial and temporal resolution retrospective cine cardiovascular magnetic resonance from shortened free breathing real-time acquisitions

    PubMed Central

    2013-01-01

    Background Cine cardiovascular magnetic resonance (CMR) is challenging in patients who cannot perform repeated breath holds. Real-time, free-breathing acquisition is an alternative, but image quality is typically inferior. There is a clinical need for techniques that achieve similar image quality to the segmented cine using a free breathing acquisition. Previously, high quality retrospectively gated cine images have been reconstructed from real-time acquisitions using parallel imaging and motion correction. These methods had limited clinical applicability due to lengthy acquisitions and volumetric measurements obtained with such methods have not previously been evaluated systematically. Methods This study introduces a new retrospective reconstruction scheme for real-time cine imaging which aims to shorten the required acquisition. A real-time acquisition of 16-20s per acquired slice was inputted into a retrospective cine reconstruction algorithm, which employed non-rigid registration to remove respiratory motion and SPIRiT non-linear reconstruction with temporal regularization to fill in missing data. The algorithm was used to reconstruct cine loops with high spatial (1.3-1.8 × 1.8-2.1 mm2) and temporal resolution (retrospectively gated, 30 cardiac phases, temporal resolution 34.3 ± 9.1 ms). Validation was performed in 15 healthy volunteers using two different acquisition resolutions (256 × 144/192 × 128 matrix sizes). For each subject, 9 to 12 short axis and 3 long axis slices were imaged with both segmented and real-time acquisitions. The retrospectively reconstructed real-time cine images were compared to a traditional segmented breath-held acquisition in terms of image quality scores. Image quality scoring was performed by two experts using a scale between 1 and 5 (poor to good). For every subject, LAX and three SAX slices were selected and reviewed in the random order. The reviewers were blinded to the reconstruction approach and

  16. Coordinated transporter activity shapes high-affinity iron acquisition in cyanobacteria

    PubMed Central

    Kranzler, Chana; Lis, Hagar; Finkel, Omri M; Schmetterer, Georg; Shaked, Yeala; Keren, Nir

    2014-01-01

    Iron bioavailability limits biological activity in many aquatic and terrestrial environments. Broad scale genomic meta-analyses indicated that within a single organism, multiple iron transporters may contribute to iron acquisition. Here, we present a functional characterization of a cyanobacterial iron transport pathway that utilizes concerted transporter activities. Cyanobacteria are significant contributors to global primary productivity with high iron demands. Certain cyanobacterial species employ a siderophore-mediated uptake strategy; however, many strains possess neither siderophore biosynthesis nor siderophore transport genes. The unicellular, planktonic, freshwater cyanobacterium, Synechocystis sp. PCC 6803, employs an alternative to siderophore-based uptake-reduction of Fe(III) species before transport through the plasma membrane. In this study, we combine short-term radioactive iron uptake and reduction assays with a range of disruption mutants to generate a working model for iron reduction and uptake in Synechocystis sp. PCC 6803. We found that the Fe(II) transporter, FeoB, is the major iron transporter in this organism. In addition, we uncovered a link between a respiratory terminal oxidase (Alternate Respiratory Terminal Oxidase) and iron reduction - suggesting a coupling between these two electron transfer reactions. Furthermore, quantitative RNA transcript analysis identified a function for subunits of the Fe(III) transporter, FutABC, in modulating reductive iron uptake. Collectively, our results provide a molecular basis for a tightly coordinated, high-affinity iron transport system. PMID:24088625

  17. Data Acquisition in a High Harmonic Generation Lab and at LCLS

    SciTech Connect

    Hirokawa, Takako; /U. Colorado, Boulder /SLAC

    2011-06-22

    In this paper, we examine data acquisition in a high harmonic generation (HHG) lab and preliminary data analysis with the Cyclohexadiene Collaboration at the Linac Coherent Lightsource (LCLS) at SLAC National Accelerator Laboratory. HHG experiments have a large number of parameters that need to be monitored constantly. In particular, the pressure of the target is critical to HHG yield. However, this pressure can fluctuate wildly and without a tool to monitor it, it is difficult to analyze the correlation between HHG yield and the pressure. I used the Arduino microcontroller board and created a complementary MATLAB graphical user interface (GUI), thereby enhancing the ease with which users can acquire time-stamped parameter data. Using the Arduino, it is much easier to match the pressure to the corresponding HHG yield. Collecting data by using the Arduino and the GUI is flexible, user-friendly, and cost-effective. In the future, we hope to be able to control and monitor parts of the lab with the Arduino alone. While more parameter information is needed in the HHG lab, we needed to reduce the amount of data during the cyclohexadiene collaboration. This was achieved by sorting the data into bins and filtering out unnecessary details. This method was highly effective in that it minimized the amount of data without losing any valuable information. This effective preliminary data analysis technique will continue to be used to decrease the size of the collected data.

  18. High Speed Multichannel Charge Sensitive Data Acquisition System with Self-Triggered Event Timing.

    PubMed

    Tremsin, Anton S; Siegmund, Oswald H W; Vallerga, John V; Raffanti, Rick; Weiss, Shimon; Michalet, Xavier

    2009-06-16

    A number of modern experiments require simultaneous measurement of charges on multiple channels at > MHz event rates with an accuracy of 100-1000 e(-) rms. One widely used data processing scheme relies on application of specific integrated circuits enabling multichannel analog peak detection asserted by an external trigger followed by a serial/sparsified readout. Although this configuration minimizes the back end electronics, its counting rate capability is limited by the speed of the serial readout. Recent advances in analog to digital converters and FPGA devices enable fully parallel high speed multichannel data processing with digital peak detection enhanced by finite impulse response filtering. Not only can accurate charge values be obtained at high event rates, but the timing of the event on each channel can also be determined with high accuracy.We present the concept and first experimental tests of fully parallel 128-channel charge sensitive data processing electronics capable of measuring charges with accuracy of ~1000 e- rms. Our system does not require an external trigger and, in addition to charge values, it provides the event timing with an accuracy of ~1 ns FWHM. One of the possible applications of this system is high resolution position sensitive event counting detectors with microchannel plates combined with cross strip readout. Implementation of fast data acquisition electronics increases the counting rates of those detectors to multi-MHz level, preserving their unique capability of virtually noiseless detection of both position (with accuracy of ~10 μm FWHM) and timing (~1 ns FWHM) of individual particles, including photons, electrons, ions, neutrals, and neutrons.

  19. A Survey of Acquisition of Transferred Negation of English Syntax "with Reference to Senior High School TEFL in Mainland China"

    ERIC Educational Resources Information Center

    Fuli, Liu; Shuang, Song

    2015-01-01

    This study investigates the learning situation of senior high school students in mainland China about acquisition of transferred negation of English sentence structure. Through translation test and questionnaire investigation, a survey is made about this language learning phenomenon among 173 students. From the study it is found that students…

  20. FPGA Based High Speed Data Acquisition System for Electrical Impedance Tomography.

    PubMed

    Khan, S; Borsic, A; Manwaring, Preston; Hartov, Alexander; Halter, Ryan

    2013-03-01

    Electrical Impedance Tomography (EIT) systems are used to image tissue bio-impedance. EIT provides a number of features making it attractive for use as a medical imaging device including the ability to image fast physiological processes (>60 Hz), to meet a range of clinical imaging needs through varying electrode geometries and configurations, to impart only non-ionizing radiation to a patient, and to map the significant electrical property contrasts present between numerous benign and pathological tissues. To leverage these potential advantages for medical imaging, we developed a modular 32 channel data acquisition (DAQ) system using National Instruments' PXI chassis, along with FPGA, ADC, Signal Generator and Timing and Synchronization modules. To achieve high frame rates, signal demodulation and spectral characteristics of higher order harmonics were computed using dedicated FFT-hardware built into the FPGA module. By offloading the computing onto FPGA, we were able to achieve a reduction in throughput required between the FPGA and PC by a factor of 32:1. A custom designed analog front end (AFE) was used to interface electrodes with our system. Our system is wideband, and capable of acquiring data for input signal frequencies ranging from 100 Hz to 12 MHz. The modular design of both the hardware and software will allow this system to be flexibly configured for the particular clinical application.

  1. FPGA Based High Speed Data Acquisition System for Electrical Impedance Tomography

    NASA Astrophysics Data System (ADS)

    Khan, S.; Borsic, A.; Manwaring, Preston; Hartov, Alexander; Halter, Ryan

    2013-04-01

    Electrical Impedance Tomography (EIT) systems are used to image tissue bio-impedance. EIT provides a number of features making it attractive for use as a medical imaging device including the ability to image fast physiological processes (>60 Hz), to meet a range of clinical imaging needs through varying electrode geometries and configurations, to impart only non-ionizing radiation to a patient, and to map the significant electrical property contrasts present between numerous benign and pathological tissues. To leverage these potential advantages for medical imaging, we developed a modular 32 channel data acquisition (DAQ) system using National Instruments' PXI chassis, along with FPGA, ADC, Signal Generator and Timing and Synchronization modules. To achieve high frame rates, signal demodulation and spectral characteristics of higher order harmonics were computed using dedicated FFT-hardware built into the FPGA module. By offloading the computing onto FPGA, we were able to achieve a reduction in throughput required between the FPGA and PC by a factor of 32:1. A custom designed analog front end (AFE) was used to interface electrodes with our system. Our system is wideband, and capable of acquiring data for input signal frequencies ranging from 100 Hz to 12 MHz. The modular design of both the hardware and software will allow this system to be flexibly configured for the particular clinical application.

  2. A reproducible approach to high-throughput biological data acquisition and integration

    PubMed Central

    Rahnavard, Gholamali; Waldron, Levi; McIver, Lauren; Shafquat, Afrah; Franzosa, Eric A.; Miropolsky, Larissa; Sweeney, Christopher

    2015-01-01

    Modern biological research requires rapid, complex, and reproducible integration of multiple experimental results generated both internally and externally (e.g., from public repositories). Although large systematic meta-analyses are among the most effective approaches both for clinical biomarker discovery and for computational inference of biomolecular mechanisms, identifying, acquiring, and integrating relevant experimental results from multiple sources for a given study can be time-consuming and error-prone. To enable efficient and reproducible integration of diverse experimental results, we developed a novel approach for standardized acquisition and analysis of high-throughput and heterogeneous biological data. This allowed, first, novel biomolecular network reconstruction in human prostate cancer, which correctly recovered and extended the NFκB signaling pathway. Next, we investigated host-microbiome interactions. In less than an hour of analysis time, the system retrieved data and integrated six germ-free murine intestinal gene expression datasets to identify the genes most influenced by the gut microbiota, which comprised a set of immune-response and carbohydrate metabolism processes. Finally, we constructed integrated functional interaction networks to compare connectivity of peptide secretion pathways in the model organisms Escherichia coli, Bacillus subtilis, and Pseudomonas aeruginosa. PMID:26157642

  3. FPGA Based High Speed Data Acquisition System for Electrical Impedance Tomography

    PubMed Central

    Khan, S; Borsic, A; Manwaring, Preston; Hartov, Alexander; Halter, Ryan

    2014-01-01

    Electrical Impedance Tomography (EIT) systems are used to image tissue bio-impedance. EIT provides a number of features making it attractive for use as a medical imaging device including the ability to image fast physiological processes (>60 Hz), to meet a range of clinical imaging needs through varying electrode geometries and configurations, to impart only non-ionizing radiation to a patient, and to map the significant electrical property contrasts present between numerous benign and pathological tissues. To leverage these potential advantages for medical imaging, we developed a modular 32 channel data acquisition (DAQ) system using National Instruments’ PXI chassis, along with FPGA, ADC, Signal Generator and Timing and Synchronization modules. To achieve high frame rates, signal demodulation and spectral characteristics of higher order harmonics were computed using dedicated FFT-hardware built into the FPGA module. By offloading the computing onto FPGA, we were able to achieve a reduction in throughput required between the FPGA and PC by a factor of 32:1. A custom designed analog front end (AFE) was used to interface electrodes with our system. Our system is wideband, and capable of acquiring data for input signal frequencies ranging from 100 Hz to 12 MHz. The modular design of both the hardware and software will allow this system to be flexibly configured for the particular clinical application. PMID:24729790

  4. A reciprocating optical in situ tribometer with high-speed data acquisition.

    PubMed

    Becker, S; Popp, U; Greiner, C

    2016-08-01

    Tribology is the science of interacting surfaces in relative motion. Processes like the transition from static to dynamic friction are fast and complex, especially as the contacting interface is buried. A direct view at the interface, in order to gain a deeper understanding of the interaction between the materials, is therefore of great interest. The reciprocating optical in situ tribometer introduced here observes the interface of two contacting materials (one of them being optical transparent) with a high-speed camera, taking up to 230 000 frames per second. The camera is attached to an optical microscope with a magnification of up to 2500 times. Friction forces are measured by an analog laser detection setup, with a maximum sampling rate of 500 kHz. The sliding motion of the materials is realized by two displacement units. A linear positioning stage allows velocities between 500 nm/s and 100 mm/s for a maximum distance of 200 mm. For smaller velocities, and to exclude breakaway torque, a piezo actuator can be used. The maximum displacement distance of the piezo actuator is 120 μm. The smallest applicable normal load on the samples is 0.5 N which is applied by the dead weights. Tribological experiments to investigate the transition from static to dynamic friction have been performed with morphologically textured brass hemispheres in contact with the sapphire discs. Sapphire was chosen for its high hardness and optical transparency. These experiments revealed, due to the high data acquisition possible with the new setup, a so far unobserved effect during the transition from static to dynamic friction. PMID:27587154

  5. A reciprocating optical in situ tribometer with high-speed data acquisition

    NASA Astrophysics Data System (ADS)

    Becker, S.; Popp, U.; Greiner, C.

    2016-08-01

    Tribology is the science of interacting surfaces in relative motion. Processes like the transition from static to dynamic friction are fast and complex, especially as the contacting interface is buried. A direct view at the interface, in order to gain a deeper understanding of the interaction between the materials, is therefore of great interest. The reciprocating optical in situ tribometer introduced here observes the interface of two contacting materials (one of them being optical transparent) with a high-speed camera, taking up to 230 000 frames per second. The camera is attached to an optical microscope with a magnification of up to 2500 times. Friction forces are measured by an analog laser detection setup, with a maximum sampling rate of 500 kHz. The sliding motion of the materials is realized by two displacement units. A linear positioning stage allows velocities between 500 nm/s and 100 mm/s for a maximum distance of 200 mm. For smaller velocities, and to exclude breakaway torque, a piezo actuator can be used. The maximum displacement distance of the piezo actuator is 120 μm. The smallest applicable normal load on the samples is 0.5 N which is applied by the dead weights. Tribological experiments to investigate the transition from static to dynamic friction have been performed with morphologically textured brass hemispheres in contact with the sapphire discs. Sapphire was chosen for its high hardness and optical transparency. These experiments revealed, due to the high data acquisition possible with the new setup, a so far unobserved effect during the transition from static to dynamic friction.

  6. 47 CFR 90.209 - Bandwidth limitations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... bandwidth (kHz) Below 25 2 25-50 20 20 72-76 20 20 150-174 17.5 1,3 20/11.25/6 216-220 5 6.25 20/11.25/6 220... kHz. The maximum authorized bandwidth for type A3E emission is 8 kHz. (2) For operations below 25 MHz utilizing J3E emission, the bandwidth occupied by the emission shall not exceed 3000 Hz....

  7. Data Acquisition and Prompt Analysis System for High Altitude Balloon Experiments

    NASA Technical Reports Server (NTRS)

    Sarkady, A. A.; Chupp, E. L.; Dickey, J. W.

    1968-01-01

    An inexpensive and simple data acquisition system has been developed for balloon borne experiments and has been tested with a gamma ray detector in a balloon flight launched from Palestine, Texas. The detector used for the test consisted of an NaI(T1) scintillation crystal encased in a 1/8 in. plastic scintillator-charged particle shield. The combination was viewed by a single photomultiplier and charged particle gating was accomplished by a conventional phoswich discriminator. The pulse height analysis of the NaI events, not associated with prompt charged particle interactions, is accomplished by converting to a time spectrum using an airborne height to time converter. A range of pulse widths from 5 microseconds to 250 microseconds corresponds to energy losses in NaI from 100 to 1000 keV. The time spectrum information, along with charged particle events and barometric pressure, is fed to a mixer which modulates a 252.4 Mc FM transmitter. The original scintillator spectrum is recovered on the ground utilizing conversion circuitry at the receiver video output and a 128 channel commercial pulse height analyzer. The charged particle events of standard time width are stored with the spectrum at a fixed channel position and are therefore represented by a sharp line riding on the lower part of the NaI energy loss spectrum. An energy loss greater than 1000 keV is presented by the maximum pulse width of the converter and stored in the last analyzer channel. Barometric pressure data is transmitted by low frequency modulation of the sme FM carrier. In flight operation, the receiver video output can be recorded on a wide band tape recorder and simultaneously analyzed by the 128 channel analyzer, or the telemetered data can be analyzed later. The flight system features high pulse resolution, essentially instantaneous time response, high data rate, and flexibility; and is of modest cost. A detailed description of the system and operating performance is discussed.

  8. Paired comparisons of nonlinear frequency compression, extended bandwidth, and restricted bandwidth hearing-aid processing for children and adults with hearing loss

    PubMed Central

    Brennan, Marc A.; McCreery, Ryan; Kopun, Judy; Hoover, Brenda; Alexander, Joshua; Lewis, Dawna; Stelmachowicz, Patricia G.

    2014-01-01

    high frequency sounds, as demonstrated by their preference for either the extended bandwidth or nonlinear frequency compression conditions over the restricted bandwidth condition. Preference for extended bandwidth can be limited for those with greater degrees of hearing loss, but participants with greater hearing loss may be more likely to prefer nonlinear frequency compression. Further investigation using participants with more severe hearing loss may be warranted. PMID:25514451

  9. Xenon Acquisition Strategies for High-Power Electric Propulsion NASA Missions

    NASA Technical Reports Server (NTRS)

    Herman, Daniel A.; Unfried, Kenneth G.

    2015-01-01

    Solar electric propulsion (SEP) has been used for station-keeping of geostationary communications satellites since the 1980s. Solar electric propulsion has also benefitted from success on NASA Science Missions such as Deep Space One and Dawn. The xenon propellant loads for these applications have been in the 100s of kilograms range. Recent studies performed for NASA's Human Exploration and Operations Mission Directorate (HEOMD) have demonstrated that SEP is critically enabling for both near-term and future exploration architectures. The high payoff for both human and science exploration missions and technology investment from NASA's Space Technology Mission Directorate (STMD) are providing the necessary convergence and impetus for a 30-kilowatt-class SEP mission. Multiple 30-50- kilowatt Solar Electric Propulsion Technology Demonstration Mission (SEP TDM) concepts have been developed based on the maturing electric propulsion and solar array technologies by STMD with recent efforts focusing on an Asteroid Redirect Robotic Mission (ARRM). Xenon is the optimal propellant for the existing state-of-the-art electric propulsion systems considering efficiency, storability, and contamination potential. NASA mission concepts developed and those proposed by contracted efforts for the 30-kilowatt-class demonstration have a range of xenon propellant loads from 100s of kilograms up to 10,000 kilograms. This paper examines the status of the xenon industry worldwide, including historical xenon supply and pricing. The paper will provide updated information on the xenon market relative to previous papers that discussed xenon production relative to NASA mission needs. The paper will discuss the various approaches for acquiring on the order of 10 metric tons of xenon propellant to support potential near-term NASA missions. Finally, the paper will discuss acquisitions strategies for larger NASA missions requiring 100s of metric tons of xenon will be discussed.

  10. Schottky Heterodyne Receivers With Full Waveguide Bandwidth

    NASA Technical Reports Server (NTRS)

    Hesler, Jeffrey; Crowe, Thomas

    2011-01-01

    Compact THz receivers with broad bandwidth and low noise have been developed for the frequency range from 100 GHz to 1 THz. These receivers meet the requirements for high-resolution spectroscopic studies of planetary atmospheres (including the Earth s) from spacecraft, as well as airborne and balloon platforms. The ongoing research is significant not only for the development of Schottky mixers, but also for the creation of a receiver system, including the LO chain. The new receivers meet the goals of high sensitivity, compact size, low total power requirement, and operation across complete waveguide bands. The exceptional performance makes these receivers ideal for the broader range of scientific and commercial applications. These include the extension of sophisticated test and measurement equipment to 1 THz and the development of low-cost imaging systems for security applications and industrial process monitoring. As a particular example, a WR-1.9SHM (400-600 GHz) has been developed (see Figure 1), with state-of-the-art noise temperature ranging from 1,000-1,800 K (DSB) over the full waveguide band. Also, a Vector Network Analyzer extender has been developed (see Figure 2) for the WR1.5 waveguide band (500 750 GHz) with 100-dB dynamic range.

  11. Effective Communication and File-I/O Bandwidth Benchmarks

    SciTech Connect

    Koniges, A E; Rabenseifner, R

    2001-05-02

    We describe the design and MPI implementation of two benchmarks created to characterize the balanced system performance of high-performance clusters and supercomputers: b{_}eff, the communication-specific benchmark examines the parallel message passing performance of a system, and b{_}eff{_}io, which characterizes the effective 1/0 bandwidth. Both benchmarks have two goals: (a) to get a detailed insight into the Performance strengths and weaknesses of different parallel communication and I/O patterns, and based on this, (b) to obtain a single bandwidth number that characterizes the average performance of the system namely communication and 1/0 bandwidth. Both benchmarks use a time driven approach and loop over a variety of communication and access patterns to characterize a system in an automated fashion. Results of the two benchmarks are given for several systems including IBM SPs, Cray T3E, NEC SX-5, and Hitachi SR 8000. After a redesign of b{_}eff{_}io, I/O bandwidth results for several compute partition sizes are achieved in an appropriate time for rapid benchmarking.

  12. Bandwidth utilization maximization of scientific RF communication systems

    SciTech Connect

    Rey, D.; Ryan, W.; Ross, M.

    1997-01-01

    A method for more efficiently utilizing the frequency bandwidth allocated for data transmission is presented. Current space and range communication systems use modulation and coding schemes that transmit 0.5 to 1.0 bits per second per Hertz of radio frequency bandwidth. The goal in this LDRD project is to increase the bandwidth utilization by employing advanced digital communications techniques. This is done with little or no increase in the transmit power which is usually very limited on airborne systems. Teaming with New Mexico State University, an implementation of trellis coded modulation (TCM), a coding and modulation scheme pioneered by Ungerboeck, was developed for this application and simulated on a computer. TCM provides a means for reliably transmitting data while simultaneously increasing bandwidth efficiency. The penalty is increased receiver complexity. In particular, the trellis decoder requires high-speed, application-specific digital signal processing (DSP) chips. A system solution based on the QualComm Viterbi decoder and the Graychip DSP receiver chips is presented.

  13. D0 data acquisition: High speed data paths for D0

    SciTech Connect

    Cutts, D.; Hoftun, J.S.; Nesic, D. . Dept. of Physics); Johnson, C.R.; Zeller, R.T. )

    1990-01-01

    This poster is intended as a review of the Level-2 system architecture for D0, and to provide an overview of the new generation of hardware currently under development to accomplish these functions. Several operational prototypes of the system have been built and are currently in use for detector and software development, as well as cosmic ray and test beam data acquisition. Delivery of the first half of the acquisition system is scheduled for September 1990, to be used in the commissioning of the detector.

  14. High spatial resolution brain functional MRI using submillimeter balanced steady-state free precession acquisition

    SciTech Connect

    Wu, Pei-Hsin; Chung, Hsiao-Wen; Tsai, Ping-Huei; Wu, Ming-Long; Chuang, Tzu-Chao; Shih, Yi-Yu; Huang, Teng-Yi

    2013-12-15

    Purpose: One of the technical advantages of functional magnetic resonance imaging (fMRI) is its precise localization of changes from neuronal activities. While current practice of fMRI acquisition at voxel size around 3 × 3 × 3 mm{sup 3} achieves satisfactory results in studies of basic brain functions, higher spatial resolution is required in order to resolve finer cortical structures. This study investigated spatial resolution effects on brain fMRI experiments using balanced steady-state free precession (bSSFP) imaging with 0.37 mm{sup 3} voxel volume at 3.0 T. Methods: In fMRI experiments, full and unilateral visual field 5 Hz flashing checkerboard stimulations were given to healthy subjects. The bSSFP imaging experiments were performed at three different frequency offsets to widen the coverage, with functional activations in the primary visual cortex analyzed using the general linear model. Variations of the spatial resolution were achieved by removing outerk-space data components. Results: Results show that a reduction in voxel volume from 3.44 × 3.44 × 2 mm{sup 3} to 0.43 × 0.43 × 2 mm{sup 3} has resulted in an increase of the functional activation signals from (7.7 ± 1.7)% to (20.9 ± 2.0)% at 3.0 T, despite of the threefold SNR decreases in the original images, leading to nearly invariant functional contrast-to-noise ratios (fCNR) even at high spatial resolution. Activation signals aligning nicely with gray matter sulci at high spatial resolution would, on the other hand, have possibly been mistaken as noise at low spatial resolution. Conclusions: It is concluded that the bSSFP sequence is a plausible technique for fMRI investigations at submillimeter voxel widths without compromising fCNR. The reduction of partial volume averaging with nonactivated brain tissues to retain fCNR is uniquely suitable for high spatial resolution applications such as the resolving of columnar organization in the brain.

  15. Enhanced spectral efficiency using bandwidth switchable SAW filtering for mobile satellite communications systems

    NASA Technical Reports Server (NTRS)

    Peach, Robert; Malarky, Alastair

    1990-01-01

    Currently proposed mobile satellite communications systems require a high degree of flexibility in assignment of spectral capacity to different geographic locations. Conventionally this results in poor spectral efficiency which may be overcome by the use of bandwidth switchable filtering. Surface acoustic wave (SAW) technology makes it possible to provide banks of filters whose responses may be contiguously combined to form variable bandwidth filters with constant amplitude and phase responses across the entire band. The high selectivity possible with SAW filters, combined with the variable bandwidth capability, makes it possible to achieve spectral efficiencies over the allocated bandwidths of greater than 90 percent, while retaining full system flexibility. Bandwidth switchable SAW filtering (BSSF) achieves these gains with a negligible increase in hardware complexity.

  16. MATLAB implementation of a dynamic clamp with bandwidth >125 KHz capable of generating INa at 37°C

    PubMed Central

    Clausen, Chris; Valiunas, Virginijus; Brink, Peter R.; Cohen, Ira S.

    2012-01-01

    We describe the construction of a dynamic clamp with bandwidth >125 KHz that utilizes a high performance, yet low cost, standard home/office PC interfaced with a high-speed (16 bit) data acquisition module. High bandwidth is achieved by exploiting recently available software advances (code-generation technology, optimized real-time kernel). Dynamic-clamp programs are constructed using Simulink, a visual programming language. Blocks for computation of membrane currents are written in the high-level matlab language; no programming in C is required. The instrument can be used in single- or dual-cell configurations, with the capability to modify programs while experiments are in progress. We describe an algorithm for computing the fast transient Na+ current (INa) in real time, and test its accuracy and stability using rate constants appropriate for 37°C. We then construct a program capable of supplying three currents to a cell preparation: INa, the hyperpolarizing-activated inward pacemaker current (If), and an inward-rectifier K+ current (IK1). The program corrects for the IR drop due to electrode current flow, and also records all voltages and currents. We tested this program on dual patch-clamped HEK293 cells where the dynamic clamp controls a current-clamp amplifier and a voltage-clamp amplifier controls membrane potential, and current-clamped HEK293 cells where the dynamic clamp produces spontaneous pacing behavior exhibiting Na+ spikes in otherwise passive cells. PMID:23224681

  17. High dynamic range diamond detector acquisition system for beam wire scanner applications

    NASA Astrophysics Data System (ADS)

    Sirvent, J. L.; Dehning, B.; Piselli, E.; Emery, J.; Dieguez, A.

    2016-03-01

    The CERN Beam Instrumentation group has been working during the last years on the beam wire scanners upgrade to cope up with the increasing requirements of CERN experiments. These devices are used to measure the beam profile by crossing a thin wire through a circulating beam, the resulting secondary particles produced from beam/wire interaction are detected and correlated with the wire position to reconstruct the beam profile. The upgraded secondary particles acquisition electronics will use polycrystalline chemical vapour deposition (pCVD) diamond detectors for particle shower measurements, with low noise acquisitions performed on the tunnel, near the detector. The digital data is transmitted to the surface through an optical link with the GBT protocol. Two integrator ASICs (ICECAL and QIE10) are being characterized and compared for detector readout with the complete acquisition chain prototype. This contribution presents the project status, the QIE10 front-end performance and the first measurements with the complete acquisition system prototype. In addition, diamond detector signals from particle showers generated by an operational beam wire scanner are analysed and compared with an operational system.

  18. iGrid2002 Demonstration: Bandwidth from the Low Lands

    SciTech Connect

    Cottrell, Les

    2002-11-01

    We report on a demonstration of several complementary high performance end-to-end active network throughput measurement tools. These include: the PingWorld Java applet that displays the Round Trip Time (RTT) and losses to sites around the world from the user's host; the multi-path analysis tool that visualizes common paths from traceroutes to selected hosts; the IEPM high-performance BandWidth monitoring toolkit which gives achievable throughput for several types of TCP data transfer applications; and the Available Bandwidth Estimation (ABWE) tool that reports in real time the available bandwidth to several paths within the range from Mbits/s to Gbit/s. We also demonstrated sending high-speed data from 4 hosts at iGrid2002 to over 30 hosts in 10 countries to simulate a high energy physics experiment distributing data to collaborators. The demonstration utilized the high-speed, long latency, trans-Atlantic network set up for iGrid2002 in Amsterdam during September 2002.

  19. High Speed PC Based Data Acquisition and Instrumentation for Measurement of Simulated Low Earth Orbit Thermally Induced Disturbances

    NASA Technical Reports Server (NTRS)

    Sills, Joel W., Jr.; Griffin, Thomas J. (Technical Monitor)

    2001-01-01

    The Hubble Space Telescope (HST) Disturbance Verification Test (DVT) was conducted to characterize responses of the Observatory's new set of rigid solar array's (SA3) to thermally induced 'creak' or stiction releases. The data acquired in the DVT were used in verification of the HST Pointing Control System on-orbit performance, post-Servicing Mission 3B (SM3B). The test simulated the on-orbit environment on a deployed SA3 flight wing. Instrumentation for this test required pretest simulations in order to select the correct sensitivities. Vacuum compatible, highly accurate accelerometers and force gages were used for this test. The complexity of the test, as well as a short planning schedule, required a data acquisition system that was easy to configure, highly flexible, and extremely robust. A PC Windows oriented data acquisition system meets these requirements, allowing the test engineers to minimize the time required to plan and perform complex environmental test. The SA3 DVT provided a direct practical and complex demonstration of the versatility that PC based data acquisition systems provide. Two PC based data acquisition systems were assembled to acquire, process, distribute, and provide real time processing for several types of transducers used in the SA3 DVT. A high sample rate digital tape recorder was used to archive the sensor signals. The two systems provided multi-channel hardware and software architecture and were selected based on the test requirements. How these systems acquire and processes multiple data rates from different transducer types is discussed, along with the system hardware and software architecture.

  20. Adaptive low-bandwidth tracking of Galileo and Pioneer 10 carriers

    NASA Technical Reports Server (NTRS)

    Watola, D. A.

    1992-01-01

    In the Deep Space Network, tracking of residual carrier phase typically occurs with a fixed-bandwidth phase-locked loop using a bandwidth sufficiently wide to prevent loss of lock under worst-case conditions of signal dynamics, received signal phase noise, and receiver phase noise. Much of the time, however, such a high bandwidth is not required and may inflict unnecessarily heavy penalties on loop signal-to-noise ratios. This article describes a technique for improving tracking performance by permitting initial tracking at narrow bandwidths and gradually widening the loop as needed. The cost is a requirement for signal buffering, which is relatively inexpensive for low data rate applications. Results based on off-line processing of recorded carrier data from Galileo and Pioneer 10 are presented, and show potential 10-16 dB gains in loop SNR over worst-case fixed-bandwidth tracking.

  1. Long-pulse-width narrow-bandwidth solid state laser

    DOEpatents

    Dane, C.B.; Hackel, L.A.

    1997-11-18

    A long pulse laser system emits 500-1000 ns quasi-rectangular pulses at 527 nm with near diffraction-limited divergence and near transform-limited bandwidth. The system consists of one or more flashlamp-pumped Nd:glass zig-zag amplifiers, a very low threshold stimulated-Brillouin-scattering (SBS) phase conjugator system, and a free-running single frequency Nd:YLF master oscillator. Completely passive polarization switching provides eight amplifier gain passes. Multiple frequency output can be generated by using SBS cells having different pressures of a gaseous SBS medium or different SBS materials. This long pulse, low divergence, narrow-bandwidth, multi-frequency output laser system is ideally suited for use as an illuminator for long range speckle imaging applications. Because of its high average power and high beam quality, this system has application in any process which would benefit from a long pulse format, including material processing and medical applications. 5 figs.

  2. Long-pulse-width narrow-bandwidth solid state laser

    DOEpatents

    Dane, C. Brent; Hackel, Lloyd A.

    1997-01-01

    A long pulse laser system emits 500-1000 ns quasi-rectangular pulses at 527 nm with near diffraction-limited divergence and near transform-limited bandwidth. The system consists of one or more flashlamp-pumped Nd:glass zig-zag amplifiers, a very low threshold stimulated-Brillouin-scattering (SBS) phase conjugator system, and a free-running single frequency Nd:YLF master oscillator. Completely passive polarization switching provides eight amplifier gain passes. Multiple frequency output can be generated by using SBS cells having different pressures of a gaseous SBS medium or different SBS materials. This long pulse, low divergence, narrow-bandwidth, multi-frequency output laser system is ideally suited for use as an illuminator for long range speckle imaging applications. Because of its high average power and high beam quality, this system has application in any process which would benefit from a long pulse format, including material processing and medical applications.

  3. Exploiting material softening in hard PZTs for resonant bandwidth enhancement

    NASA Astrophysics Data System (ADS)

    Leadenham, S.; Moura, A.; Erturk, A.

    2016-04-01

    Intentionally designed nonlinearities have been employed by several research groups to enhance the frequency bandwidth of vibration energy harvesters. Another type of nonlinear resonance behavior emerges from the piezoelectric constitutive behavior for high excitation levels and is manifested in the form of softening stiffness. This material nonlinearity does not result in the jump phenomenon in soft piezoelectric ceramics, e.g. PZT-5A and PZT-5H, due to their large internal dissipation. This paper explores the potential for wideband energy harvesting using a hard (relatively high quality factor) PZT-8 bimorph by exploiting its material softening. A wide range of base excitation experiments conducted for a set of resistive electrical loads confirms the frequency bandwidth enhancement.

  4. Multiprocessor data acquisition system for high event rates at the Heidelberg/Darmstadt crystal ball

    SciTech Connect

    Ender, C.; Manner, R.; Bauer, P. . Physikalisches Inst.)

    1989-10-01

    The Heidelberg/Darmstadt crystal ball detector uses a distributed data acquisition system consisting of a Fastbus/CAMAC front-end, the Heidelberg Polyp multiprocessor system with 30 processor modules, and an online VAX. For this heterogeneous multicomputer system a distributed real-time operating system was developed. The distributed computer system allows for event rates up to 2 x 10/sup 4/ events/s. It is managed user transparently and fault tolerantly.

  5. Kernel bandwidth estimation for nonparametric modeling.

    PubMed

    Bors, Adrian G; Nasios, Nikolaos

    2009-12-01

    Kernel density estimation is a nonparametric procedure for probability density modeling, which has found several applications in various fields. The smoothness and modeling ability of the functional approximation are controlled by the kernel bandwidth. In this paper, we describe a Bayesian estimation method for finding the bandwidth from a given data set. The proposed bandwidth estimation method is applied in three different computational-intelligence methods that rely on kernel density estimation: 1) scale space; 2) mean shift; and 3) quantum clustering. The third method is a novel approach that relies on the principles of quantum mechanics. This method is based on the analogy between data samples and quantum particles and uses the SchrOdinger potential as a cost function. The proposed methodology is used for blind-source separation of modulated signals and for terrain segmentation based on topography information.

  6. Development and application of a high speed digital data acquisition technique to study steam bubble collapse using particle image velocimetry

    SciTech Connect

    Schmidl, W.D.

    1992-08-01

    The use of a Particle Image Velocimetry (PIV) method, which uses digital cameras for data acquisition, for studying high speed fluid flows is usually limited by the digital camera`s frame acquisition rate. The velocity of the fluid under study has to be limited to insure that the tracer seeds suspended in the fluid remain in the camera`s focal plane for at least two consecutive images. However, the use of digital cameras for data acquisition is desirable to simplify and expedite the data analysis process. A technique was developed which will measure fluid velocities with PIV techniques using two successive digital images and two different framing rates simultaneously. The first part of the method will measure changes which occur to the flow field at the relatively slow framing rate of 53.8 ms. The second part will measure changes to the same flow field at the relatively fast framing rate of 100 to 320 {mu}s. The effectiveness of this technique was tested by studying the collapse of steam bubbles in a subcooled tank of water, a relatively high speed phenomena. The tracer particles were recorded and velocity vectors for the fluid were obtained far from the steam bubble collapse.

  7. Development and application of a high speed digital data acquisition technique to study steam bubble collapse using particle image velocimetry

    SciTech Connect

    Schmidl, W.D.

    1992-08-01

    The use of a Particle Image Velocimetry (PIV) method, which uses digital cameras for data acquisition, for studying high speed fluid flows is usually limited by the digital camera's frame acquisition rate. The velocity of the fluid under study has to be limited to insure that the tracer seeds suspended in the fluid remain in the camera's focal plane for at least two consecutive images. However, the use of digital cameras for data acquisition is desirable to simplify and expedite the data analysis process. A technique was developed which will measure fluid velocities with PIV techniques using two successive digital images and two different framing rates simultaneously. The first part of the method will measure changes which occur to the flow field at the relatively slow framing rate of 53.8 ms. The second part will measure changes to the same flow field at the relatively fast framing rate of 100 to 320 [mu]s. The effectiveness of this technique was tested by studying the collapse of steam bubbles in a subcooled tank of water, a relatively high speed phenomena. The tracer particles were recorded and velocity vectors for the fluid were obtained far from the steam bubble collapse.

  8. Real-time control and data-acquisition system for high-energy neutral-beam injectors

    SciTech Connect

    Glad, A S; Jacobson, V

    1981-12-01

    The need for a real-time control system and a data acquisition, processing and archiving system operating in parallel on the same computer became a requirement on General Atomic's Doublet III fusion energy project with the addition of high energy neutral beam injectors. The data acquisition processing and archiving system is driven from external events and is sequenced through each experimental shot utilizing ModComp's intertask message service. This system processes, archives and displays on operator console CRTs all physics diagnostic data related to the neutral beam injectores such as temperature, beam alignment, etc. The real-time control system is data base driven and provides periodic monitoring and control of the numerous dynamic subsystems of the neutral beam injectors such as power supplies, timing, water cooling, etc.

  9. 47 CFR 87.135 - Bandwidth of emission.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Bandwidth of emission. 87.135 Section 87.135... Technical Requirements § 87.135 Bandwidth of emission. (a) Occupied bandwidth is the width of a frequency... equal to 0.5 percent of the total mean power of a given emission. (b) The authorized bandwidth is...

  10. 47 CFR 87.135 - Bandwidth of emission.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Bandwidth of emission. 87.135 Section 87.135... Technical Requirements § 87.135 Bandwidth of emission. (a) Occupied bandwidth is the width of a frequency... equal to 0.5 percent of the total mean power of a given emission. (b) The authorized bandwidth is...

  11. Acquisition, storage, and review of safety data from a commercial system for high temperature, short time pasteurization.

    PubMed

    Schlesser, J E; Lynn, G; Armstrong, D J; Cinar, A; Ramanauskas, P; Negiz, A

    1998-01-01

    A high temperature, short time (HTST) pasteurization system was equipped with electronic sensors to determine the temperature, pressure, flow rate, and position of the flow diversion valve. A computer for data acquisition was wired to the sensors to monitor and to record processing conditions related to public health. The processing conditions were stored in safety files on the hard drive of the computer, transferred weekly to a tape drive, and stored. The processing conditions of the HTST system were monitored for 270 d to determine the accuracy and reliability of the data acquisition system. The size of the HTST safety files ranged from 6.2 to 9.1 MB when the sensors were monitored every second. The file size was reduced to < 1.8 MB when the monitoring frequency was increased to every 5 s. To determine accuracy, the temperatures recorded by the data acquisition system were compared with the temperatures recorded by an electronic recorder controller. To determine reliability, changes in the position of the flow diversion valve were examined to identify process deviations and were compared with the event marker on circular charts. The review of the data file by the actual time method was an effective alternative to the electronic recorder controller for monitoring the completeness of data in the safety files. Off-line review to determine reliability required approximately 10 min/d of records.

  12. Development of a high speed laser scanning confocal microscope with an acquisition rate up to 200 frames per second.

    PubMed

    Choi, S; Kim, P; Boutilier, R; Kim, M Y; Lee, Y J; Lee, H

    2013-10-01

    There has been an increasing interest for observing fast biological phenomena such as cell movements in circulations and action potentials. The laser scanning confocal microscopy offers a good spatial resolution and optical sectioning ability to observe various in vivo animal models. We developed a high speed laser scanning confocal microscope capable of acquiring 512 by 512 pixel images at 200 fps (frames per second). We have incorporated a fast rotating polygonal scanning mirror with 128 facets for the X-axis scanner. In order to increase the throughput of the Y-axis scanner, we applied a bi-directional scanning method for vertical scanning. This made it possible to scan along the Y-axis two times during each scanner motion cycle. For the image acquisition, we used a custom photomultiplier tube amplifier with a broad frequency band. In addition, custom imaging software was written for the new microscope. In order to verify the acquisition speed of the developed confocal microscope, a resolution target moving at a series of constant speeds and a sedated mouse with slight movements due to heartbeats were observed. By comparing successive frames, the frame acquisition speeds were calculated.

  13. Triggering, front-end electronics, and data acquisition for high-rate beauty experiments

    SciTech Connect

    Johnson, M.; Lankford, A.J.

    1988-04-01

    The working group explored the feasibility of building a trigger and an electronics data acquisition system for both collider and fixed target experiments. There appears to be no fundamental technical limitation arising from either the rate or the amount of data for a collider experiment. The fixed target experiments will likely require a much higher rate because of the smaller cross section. Rates up to one event per RF bucket (50 MHz) appear to be feasible. Higher rates depend on the details of the particular experiment and trigger. Several ideas were presented on multiplicity jump and impact parameter triggers for fixed target experiments. 14 refs., 3 figs.

  14. Practical continuous-variable quantum key distribution without finite sampling bandwidth effects.

    PubMed

    Li, Huasheng; Wang, Chao; Huang, Peng; Huang, Duan; Wang, Tao; Zeng, Guihua

    2016-09-01

    In a practical continuous-variable quantum key distribution system, finite sampling bandwidth of the employed analog-to-digital converter at the receiver's side may lead to inaccurate results of pulse peak sampling. Then, errors in the parameters estimation resulted. Subsequently, the system performance decreases and security loopholes are exposed to eavesdroppers. In this paper, we propose a novel data acquisition scheme which consists of two parts, i.e., a dynamic delay adjusting module and a statistical power feedback-control algorithm. The proposed scheme may improve dramatically the data acquisition precision of pulse peak sampling and remove the finite sampling bandwidth effects. Moreover, the optimal peak sampling position of a pulse signal can be dynamically calibrated through monitoring the change of the statistical power of the sampled data in the proposed scheme. This helps to resist against some practical attacks, such as the well-known local oscillator calibration attack. PMID:27607653

  15. Practical continuous-variable quantum key distribution without finite sampling bandwidth effects.

    PubMed

    Li, Huasheng; Wang, Chao; Huang, Peng; Huang, Duan; Wang, Tao; Zeng, Guihua

    2016-09-01

    In a practical continuous-variable quantum key distribution system, finite sampling bandwidth of the employed analog-to-digital converter at the receiver's side may lead to inaccurate results of pulse peak sampling. Then, errors in the parameters estimation resulted. Subsequently, the system performance decreases and security loopholes are exposed to eavesdroppers. In this paper, we propose a novel data acquisition scheme which consists of two parts, i.e., a dynamic delay adjusting module and a statistical power feedback-control algorithm. The proposed scheme may improve dramatically the data acquisition precision of pulse peak sampling and remove the finite sampling bandwidth effects. Moreover, the optimal peak sampling position of a pulse signal can be dynamically calibrated through monitoring the change of the statistical power of the sampled data in the proposed scheme. This helps to resist against some practical attacks, such as the well-known local oscillator calibration attack.

  16. 47 CFR 24.131 - Authorized bandwidth.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... will be 10 kHz for 12.5 kHz channels and 45 kHz for 50 kHz channels. For aggregated adjacent channels, a maximum authorized bandwidth of 5 kHz less than the total aggregated channel width is permitted....

  17. Increasing the quantitative bandwidth of NMR measurements.

    PubMed

    Power, J E; Foroozandeh, M; Adams, R W; Nilsson, M; Coombes, S R; Phillips, A R; Morris, G A

    2016-02-18

    The frequency range of quantitative NMR is increased from tens to hundreds of kHz by a new pulse sequence, CHORUS. It uses chirp pulses to excite uniformly over very large bandwidths, yielding accurate integrals even for nuclei such as (19)F that have very wide spectra. PMID:26789115

  18. Increasing the quantitative bandwidth of NMR measurements.

    PubMed

    Power, J E; Foroozandeh, M; Adams, R W; Nilsson, M; Coombes, S R; Phillips, A R; Morris, G A

    2016-02-18

    The frequency range of quantitative NMR is increased from tens to hundreds of kHz by a new pulse sequence, CHORUS. It uses chirp pulses to excite uniformly over very large bandwidths, yielding accurate integrals even for nuclei such as (19)F that have very wide spectra.

  19. 47 CFR 2.202 - Bandwidths.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... emission I. NO MODULATING SIGNAL Continuous wave emission N0N (zero) II. AMPLITUDE MODULATION 1. Signal With Quantized or Digital Information Continuous wave telegraphy Bn=BK, K=5 for fading circuits, K=3... channels) Bn=sum of M for each sideband 2 channels, M=3000, Bandwidth: 6000 Hz=6 kHz 6K00B8E 3....

  20. 47 CFR 2.202 - Bandwidths.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... emission I. NO MODULATING SIGNAL Continuous wave emission N0N (zero) II. AMPLITUDE MODULATION 1. Signal With Quantized or Digital Information Continuous wave telegraphy Bn=BK, K=5 for fading circuits, K=3... channels) Bn=sum of M for each sideband 2 channels, M=3000, Bandwidth: 6000 Hz=6 kHz 6K00B8E 3....

  1. 47 CFR 2.202 - Bandwidths.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... emission I. NO MODULATING SIGNAL Continuous wave emission N0N (zero) II. AMPLITUDE MODULATION 1. Signal With Quantized or Digital Information Continuous wave telegraphy Bn=BK, K=5 for fading circuits, K=3... channels) Bn=sum of M for each sideband 2 channels, M=3000, Bandwidth: 6000 Hz=6 kHz 6K00B8E 3....

  2. 47 CFR 2.202 - Bandwidths.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... emission I. NO MODULATING SIGNAL Continuous wave emission N0N (zero) II. AMPLITUDE MODULATION 1. Signal With Quantized or Digital Information Continuous wave telegraphy Bn=BK, K=5 for fading circuits, K=3... channels) Bn=sum of M for each sideband 2 channels, M=3000, Bandwidth: 6000 Hz=6 kHz 6K00B8E 3....

  3. Bandwidth, Broadband, and Planning for Public Access

    ERIC Educational Resources Information Center

    Blowers, Helene

    2012-01-01

    Broadband and bandwidth allocation is an essential technology planning activity that libraries should address on a continual basis. There are five key factors that will impact your network's performance: 1. infrastructure, 2. network load, 3. workstation performance, 4. prioritization of services, and 5. network management. The author thinks it's…

  4. Adaptive bandwidth measurements of importance functions for speech intelligibility prediction

    PubMed Central

    Whitmal, Nathaniel A.; DeRoy, Kristina

    2011-01-01

    The Articulation Index (AI) and Speech Intelligibility Index (SII) predict intelligibility scores from measurements of speech and hearing parameters. One component in the prediction is the “importance function,” a weighting function that characterizes contributions of particular spectral regions of speech to speech intelligibility. Previous work with SII predictions for hearing-impaired subjects suggests that prediction accuracy might improve if importance functions for individual subjects were available. Unfortunately, previous importance function measurements have required extensive intelligibility testing with groups of subjects, using speech processed by various fixed-bandwidth low-pass and high-pass filters. A more efficient approach appropriate to individual subjects is desired. The purpose of this study was to evaluate the feasibility of measuring importance functions for individual subjects with adaptive-bandwidth filters. In two experiments, ten subjects with normal-hearing listened to vowel-consonant-vowel (VCV) nonsense words processed by low-pass and high-pass filters whose bandwidths were varied adaptively to produce specified performance levels in accordance with the transformed up-down rules of Levitt [(1971). J. Acoust. Soc. Am. 49, 467–477]. Local linear psychometric functions were fit to resulting data and used to generate an importance function for VCV words. Results indicate that the adaptive method is reliable and efficient, and produces importance function data consistent with that of the corresponding AI/SII importance function. PMID:22225057

  5. Fast auto-acquisition tomography tilt series by using HD video camera in ultra-high voltage electron microscope.

    PubMed

    Nishi, Ryuji; Cao, Meng; Kanaji, Atsuko; Nishida, Tomoki; Yoshida, Kiyokazu; Isakozawa, Shigeto

    2014-11-01

    The ultra-high voltage electron microscope (UHVEM) H-3000 with the world highest acceleration voltage of 3 MV can observe remarkable three dimensional microstructures of microns-thick samples[1]. Acquiring a tilt series of electron tomography is laborious work and thus an automatic technique is highly desired. We proposed the Auto-Focus system using image Sharpness (AFS)[2,3] for UHVEM tomography tilt series acquisition. In the method, five images with different defocus values are firstly acquired and the image sharpness are calculated. The sharpness are then fitted to a quasi-Gaussian function to decide the best focus value[3]. Defocused images acquired by the slow scan CCD (SS-CCD) camera (Hitachi F486BK) are of high quality but one minute is taken for acquisition of five defocused images.In this study, we introduce a high-definition video camera (HD video camera; Hamamatsu Photonics K. K. C9721S) for fast acquisition of images[4]. It is an analog camera but the camera image is captured by a PC and the effective image resolution is 1280×1023 pixels. This resolution is lower than that of the SS-CCD camera of 4096×4096 pixels. However, the HD video camera captures one image for only 1/30 second. In exchange for the faster acquisition the S/N of images are low. To improve the S/N, 22 captured frames are integrated so that each image sharpness is enough to become lower fitting error. As countermeasure against low resolution, we selected a large defocus step, which is typically five times of the manual defocus step, to discriminate different defocused images.By using HD video camera for autofocus process, the time consumption for each autofocus procedure was reduced to about six seconds. It took one second for correction of an image position and the total correction time was seven seconds, which was shorter by one order than that using SS-CCD camera. When we used SS-CCD camera for final image capture, it took 30 seconds to record one tilt image. We can obtain a tilt

  6. A single-shot, multiwavelength electro-optic data-acquisition system for inertial confinement fusion applications (invited)

    SciTech Connect

    Donaldson, W. R.; Zhao, C.; Ji, L.; Roides, R. G.; Miller, K.; Beeman, B.

    2012-10-15

    Electro-optic data-acquisition systems encode the output from voltage-history diagnostics onto optical signals. The optical signals can propagate long distances over fiber-optic links without degrading the bandwidth of the encoded signal while protecting the recording electronics from overvoltage damage. The sinusoidal response and tolerance to high-input voltages of the Mach-Zehnder modulator used for the encoding leads to the additional advantage of a high dynamic range and a reduced need for manually swapping attenuators. We have demonstrated a single-shot, electro-optic data-acquisition system with a 600:1 dynamic range. This system provides optical isolation and a bandwidth of 6 GHz. The prototype system uses multiple optical wavelengths to allow for the multiplexing of up to eight signals onto one photodetector.

  7. Risk factors for HIV acquisition in high risk women in a generalised epidemic setting

    PubMed Central

    Naicker, Nivashnee; Kharsany, Ayesha BM; Werner, Lise; van Loggerenberg, Francois; Mlisana, Koleka; Garrett, Nigel; Karim, Salim S. Abdool

    2015-01-01

    In South Africa young women bear a disproportionate burden of HIV infection however, risk factors for HIV acquisition are not fully understood in this setting. In a cohort of 245 women, we used proportional hazard regression analysis to examine the association of demographic, clinical and behavioural characteristics with HIV acquisition. The overall HIV incidence rate (IR) was 7.20 per 100 women years (wy), 95% Confidence Interval (CI) 4.50–9.80]. Women 18–24 years had the highest HIV incidence [IR 13.20 per 100 wy, 95% CI 6.59–23.62] and were almost three times more likely to acquire HIV compared to women 25 years and older [adjusted Hazard Ratio (aHR) 2.61, 95% CI 1.05–6.47]. Similarly, women in relationships with multiple sex partners had more than twice the risk of acquiring HIV when compared to women who had no partner or who had a husband or stable partner (aHR 2.47, 95% CI 0.98–6.26). HIV prevention programmes must address young women's vulnerability and sex partner reduction in this setting. PMID:25662962

  8. Acquisition of a High-precision Skilled Forelimb Reaching Task in Rats.

    PubMed

    Zemmar, Ajmal; Kast, Brigitte; Lussi, Karin; Luft, Andreas R; Schwab, Martin E

    2015-06-22

    Movements are the main measurable output of central nervous system function. Developing behavioral paradigms that allow detailed analysis of motor learning and execution is of critical importance in order to understand the principles and processes that underlie motor function. Here we present a paradigm to study movement acquisition within a daily session of training (within-session) representing the fast learning component and primary acquisition as well as skilled motor learning over several training sessions (between-session) representing the slow learning component and consolidation of the learned task. This behavioral paradigm increases the degree of difficulty and complexity of the motor skill task due to two features: First, the animal realigns its body prior to each pellet retrieval forcing renewed orientation and preventing movement execution from the same angle. Second, pellets are grasped from a vertical post that matches the diameter of the pellet and is placed in front of the cage. This requires a precise grasp for successful pellet retrieval and thus prevents simple pulling of the pellet towards the animal. In combination with novel genetics, imaging and electrophysiological technologies, this behavioral method will aid to understand the morphological, anatomical and molecular underpinnings of motor learning and memory.

  9. Configurable-bandwidth imaging spectrometer based on an acousto-optic tunable filter

    NASA Astrophysics Data System (ADS)

    Vila-Francés, Joan; Calpe-Maravilla, Javier; Muñoz-Mari, Jordi; Gómez-Chova, Luis; Amorós-López, Julia; Ribes-Gómez, Emilio; Durán-Bosch, Vicente

    2006-07-01

    This article presents a new imaging spectrometer called autonomous tunable filtering system. The instrument acquires sequential images at different spectral wavelengths in the visible and near infrared range of the electromagnetic spectrum. The spectral selection is performed by an acousto-optic tunable filter (AOTF), which is driven by a custom radio-frequency (rf) generator based on a direct digital synthesizer (DDS). The DDS allows a high flexibility in terms of acquisition speed and bandwidth selection. The rf power is dynamically controlled to drive the AOTF with the optimum value for each wavelength. The images are formed through a carefully designed optical layout and acquired with a high performance digital camera. The application software controls the instrument and acquires the raw spectral images from the camera. This software optionally corrects the image for the AOTF nonidealities, such as diffraction efficiency variations, spatial nonuniformity, and chromatic aberration, and generates a single multiband image file. Moreover, the software can calculate the reflectance or transmittance of the acquired images. The instrument has been calibrated to give precise and repetitive measurements and has been validated against a high performance point spectrometer. As a case example, the instrument has been successfully used for the mapping of chlorophyll content of plant leaves from their multispectral reflectance images.

  10. High-Speed MALDI-TOF Imaging Mass Spectrometry: Rapid Ion Image Acquisition and Considerations for Next Generation Instrumentation

    PubMed Central

    Spraggins, Jeffrey M.; Caprioli, Richard M.

    2012-01-01

    A prototype matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometer has been used for high-speed ion image acquisition. The instrument incorporates a Nd:YLF solid state laser capable of pulse repetition rates up to 5 kHz and continuous laser raster sampling for high-throughput data collection. Lipid ion images of a sagittal rat brain tissue section were collected in 10 min with an effective acquisition rate of roughly 30 pixels/s. These results represent more than a 10-fold increase in throughput compared with current commercially available instrumentation. Experiments aimed at improving conditions for continuous laser raster sampling for imaging are reported, highlighting proper laser repetition rates and stage velocities to avoid signal degradation from significant oversampling. As new high spatial resolution and large sample area applications present themselves, the development of high-speed microprobe MALDI imaging mass spectrometry is essential to meet the needs of those seeking new technologies for rapid molecular imaging. PMID:21953043

  11. Protein synthesis is not required for acquisition, consolidation, and extinction of high foot-shock active avoidance training.

    PubMed

    González-Salinas, Sofía; Medina, Andrea C; Marín-Vignando, Vera; Ruiz-López, Clyo X; Quirarte, Gina L; Prado-Alcalá, Roberto A

    2015-01-01

    Long-term memory of active avoidance in mice is not disturbed by administration of protein synthesis inhibitors (PSIs) when relatively high levels of training are used, whereas a detrimental effect is produced with lower levels of training. PSIs also disrupt extinction of avoidance behaviors in rodents, but it is not clear whether PSIs also affect this form of learning when the behavior to be extinguished was produced by a high level of training. Experiment 1 demonstrated that rats treated with the PSI cycloheximide (CXM) 30 min before training developed normal acquisition after training with either high or low foot-shock stimulation, but that memory consolidation was hindered only after low foot-shock training. Experiment 2 demonstrated that CXM disrupted extinction when administered before the first of a series of extinction sessions when low foot-shock intensity was used during training; in contrast, after training with a higher foot-shock, the PSI treatment only interfered transiently with extinction. These results indicate that acquisition, consolidation, and extinction of active avoidance learning produced by high aversive stimulation are not dependent on protein synthesis and that these processes are governed by mechanisms different from those underlying moderate forms of learning.

  12. A high dynamic range data acquisition system for a solid-state electron electric dipole moment experiment

    SciTech Connect

    Kim, Young Jin; Kunkler, Brandon; Liu, Chen-Yu; Visser, Gerard

    2012-01-15

    We have built a high precision (24-bit) data acquisition (DAQ) system capable of simultaneously sampling eight input channels for the measurement of the electric dipole moment of the electron. The DAQ system consists of two main components: a master board for DAQ control and eight individual analog-to-digital converter (ADC) boards for signal processing. This custom DAQ system provides galvanic isolation of the ADC boards from each other and the master board using fiber optic communication to reduce the possibility of ground loop pickup and attain ultimate low levels of channel cross-talk. In this paper, we describe the implementation of the DAQ system and scrutinize its performance.

  13. Bandwidth-sharing in LHCONE, an analysis of the problem

    NASA Astrophysics Data System (ADS)

    Wildish, T.

    2015-12-01

    The LHC experiments have traditionally regarded the network as an unreliable resource, one which was expected to be a major source of errors and inefficiency at the time their original computing models were derived. Now, however, the network is seen as much more capable and reliable. Data are routinely transferred with high efficiency and low latency to wherever computing or storage resources are available to use or manage them. Although there was sufficient network bandwidth for the experiments’ needs during Run-1, they cannot rely on ever-increasing bandwidth as a solution to their data-transfer needs in the future. Sooner or later they need to consider the network as a finite resource that they interact with to manage their traffic, in much the same way as they manage their use of disk and CPU resources. There are several possible ways for the experiments to integrate management of the network in their software stacks, such as the use of virtual circuits with hard bandwidth guarantees or soft real-time flow-control, with somewhat less firm guarantees. Abstractly, these can all be considered as the users (the experiments, or groups of users within the experiment) expressing a request for a given bandwidth between two points for a given duration of time. The network fabric then grants some allocation to each user, dependent on the sum of all requests and the sum of available resources, and attempts to ensure the requirements are met (either deterministically or statistically). An unresolved question at this time is how to convert the users’ requests into an allocation. Simply put, how do we decide what fraction of a network's bandwidth to allocate to each user when the sum of requests exceeds the available bandwidth? The usual problems of any resourcescheduling system arise here, namely how to ensure the resource is used efficiently and fairly, while still satisfying the needs of the users. Simply fixing quotas on network paths for each user is likely to lead

  14. Optimization of adaptive-optics systems closed-loop bandwidth settings to maximize imaging-system performance.

    PubMed

    Brigantic, R T; Roggemann, M C; Welsh, B M; Bauer, K W

    1998-02-10

    We present the results of research aimed at optimizing adaptive-optics closed-loop bandwidth settings to maximize imaging-system performance. The optimum closed-loop bandwidth settings are determined as a function of target-object light levels and atmospheric seeing conditions. Our work shows that, for bright objects, the optimum closed-loop bandwidth is near the Greenwood frequency. However, for dim objects without the use of a laser beacon the preferred closed-loop bandwidth settings are a small fraction of the Greenwood frequency. In addition, under low light levels selection of the proper closed-loop bandwidth is more critical for achieving maximum performance than it is under high light levels. We also present a strategy for selecting the closed-loop bandwidth to provide robust system performance for different target-object light levels.

  15. Flexible All-Digital Receiver for Bandwidth Efficient Modulations

    NASA Technical Reports Server (NTRS)

    Gray, Andrew; Srinivasan, Meera; Simon, Marvin; Yan, Tsun-Yee

    2000-01-01

    An all-digital high data rate parallel receiver architecture developed jointly by Goddard Space Flight Center and the Jet Propulsion Laboratory is presented. This receiver utilizes only a small number of high speed components along with a majority of lower speed components operating in a parallel frequency domain structure implementable in CMOS, and can currently process up to 600 Mbps with standard QPSK modulation. Performance results for this receiver for bandwidth efficient QPSK modulation schemes such as square-root raised cosine pulse shaped QPSK and Feher's patented QPSK are presented, demonstrating the flexibility of the receiver architecture.

  16. Identification of phosphorus deficiency responsive proteins in a high phosphorus acquisition soybean (Glycine max) cultivar through proteomic analysis.

    PubMed

    Sha, Aihua; Li, Ming; Yang, Pingfang

    2016-05-01

    As one of the major oil crops, soybean might be seriously affected by phosphorus deficiency on both yield and quality. Understanding the molecular basis of phosphorus uptake and utilization in soybean may help to develop phosphorus (P) efficient cultivars. On this purpose, we conducted a comparative proteomic analysis on a high P acquisition soybean cultivar BX10 under low and high P conditions. A total of 61 unique proteins were identified as putative P deficiency responsive proteins. These proteins were involved in carbohydrate metabolism, protein biosynthesis/processing, energy metabolism, cellular processes, environmental defense/interaction, nucleotide metabolism, signal transduction, secondary metabolism and other metabolism related processes. Several proteins involved in energy metabolism, cellular processes, and protein biosynthesis and processing were found to be up-regulated in both shoots and roots, whereas, proteins involved in carbohydrate metabolism appeared to be down-regulated. These proteins are potential candidates for improving P acquisition. These findings provide a useful starting point for further research that will provide a more comprehensive understanding of molecular mechanisms through which soybeans adapt to P deficiency condition.

  17. Compressive sensing based high-speed time-stretch optical microscopy for two-dimensional image acquisition.

    PubMed

    Guo, Qiang; Chen, Hongwei; Weng, Zhiliang; Chen, Minghua; Yang, Sigang; Xie, Shizhong

    2015-11-16

    In this paper, compressive sensing based high-speed time-stretch optical microscopy for two-dimensional (2D) image acquisition is proposed and experimentally demonstrated for the first time. A section of dispersion compensating fiber (DCF) is used to perform wavelength-to-time conversion and then ultrafast spectral shaping of broadband optical pulses can be achieved via high-speed intensity modulation. A 2D spatial disperser comprising a pair of orthogonally oriented dispersers is employed to produce spatially structured illumination for 2D image acquisition and a section of single mode fiber (SMF) is utilized for pulse compression in the optical domain. In our scheme, a 1.2-GHz photodetector and a 50-MHz analog-to-digital converter (ADC) are used to acquire the energy of the compressed pulses. Image reconstructions are demonstrated at a frame rate of 500 kHz and a sixteen-fold image compression is achieved in our proof-of-concept demonstration.

  18. Streamlined acquisition handbook

    NASA Technical Reports Server (NTRS)

    1990-01-01

    NASA has always placed great emphasis on the acquisition process, recognizing it as among its most important activities. This handbook is intended to facilitate the application of streamlined acquisition procedures. The development of these procedures reflects the efforts of an action group composed of NASA Headquarters and center acquisition professionals. It is the intent to accomplish the real change in the acquisition process as a result of this effort. An important part of streamlining the acquisition process is a commitment by the people involved in the process to accomplishing acquisition activities quickly and with high quality. Too often we continue to accomplish work in 'the same old way' without considering available alternatives which would require no changes to regulations, approvals from Headquarters, or waivers of required practice. Similarly, we must be sensitive to schedule opportunities throughout the acquisition cycle, not just once the purchase request arrives at the procurement office. Techniques that have been identified as ways of reducing acquisition lead time while maintaining high quality in our acquisition process are presented.

  19. Role of Bandwidth in Computation of NDVI From Landsat TM and NOAA AVHRR Bands

    NASA Astrophysics Data System (ADS)

    Gupta, R. K.; Vijayan, D.; Prasad, T. S.; Tirumaladevi, N. Ch.

    The observations for wheat, onion, potato and chickpea over the Crop Growth Cycle (CGC) in 3 nm bandwidth were converted to AVHRR and TM bands in visible/red and near-IR spectral regions. Correlation between TM and AVHRR NDVI were very high for all these crops. The additional 0.725-0.76 μm bandwidth in AVHRR as compared to TM was causing reduction in NDVI values for AVHRR when crop NDVI value was more than 0.46

  20. Liquid oxygen liquid acquisition device bubble point tests with high pressure lox at elevated temperatures

    NASA Astrophysics Data System (ADS)

    Jurns, J. M.; Hartwig, J. W.

    2012-04-01

    When transferring propellant in space, it is most efficient to transfer single phase liquid from a propellant tank to an engine. In earth's gravity field or under acceleration, propellant transfer is fairly simple. However, in low gravity, withdrawing single-phase fluid becomes a challenge. A variety of propellant management devices (PMDs) are used to ensure single-phase flow. One type of PMD, a liquid acquisition device (LAD) takes advantage of capillary flow and surface tension to acquire liquid. The present work reports on testing with liquid oxygen (LOX) at elevated pressures (and thus temperatures) (maximum pressure 1724 kPa and maximum temperature 122 K) as part of NASA's continuing cryogenic LAD development program. These tests evaluate LAD performance for LOX stored in higher pressure vessels that may be used in propellant systems using pressure fed engines. Test data shows a significant drop in LAD bubble point values at higher liquid temperatures, consistent with lower liquid surface tension at those temperatures. Test data also indicates that there are no first order effects of helium solubility in LOX on LAD bubble point prediction. Test results here extend the range of data for LOX fluid conditions, and provide insight into factors affecting predicting LAD bubble point pressures.

  1. Liquid Oxygen Liquid Acquisition Device Bubble Point Tests with High Pressure LOX at Elevated Temperatures

    NASA Technical Reports Server (NTRS)

    Jurns, John M.; Hartwig, Jason W.

    2011-01-01

    When transferring propellant in space, it is most efficient to transfer single phase liquid from a propellant tank to an engine. In earth s gravity field or under acceleration, propellant transfer is fairly simple. However, in low gravity, withdrawing single-phase fluid becomes a challenge. A variety of propellant management devices (PMD) are used to ensure single-phase flow. One type of PMD, a liquid acquisition device (LAD) takes advantage of capillary flow and surface tension to acquire liquid. The present work reports on testing with liquid oxygen (LOX) at elevated pressures (and thus temperatures) (maximum pressure 1724 kPa and maximum temperature 122K) as part of NASA s continuing cryogenic LAD development program. These tests evaluate LAD performance for LOX stored in higher pressure vessels that may be used in propellant systems using pressure fed engines. Test data shows a significant drop in LAD bubble point values at higher liquid temperatures, consistent with lower liquid surface tension at those temperatures. Test data also indicates that there are no first order effects of helium solubility in LOX on LAD bubble point prediction. Test results here extend the range of data for LOX fluid conditions, and provide insight into factors affecting predicting LAD bubble point pressures.

  2. Digital control and data acquisition for high-value GTA welding

    NASA Astrophysics Data System (ADS)

    George, T. G.; Franco-Ferreira, E. A.

    Electric power for the Cassini space probe will be provided by radioisotope thermoelectric generators (RTG's) thermally driven by General-Purpose Heat Source (GPHS) modules. Each GPHS module contains four, 150-g, pellets of Pu-238O2, and each of the four pellets is encapsulated within a thin-wall iridium-alloy shell. GTA girth welding of these capsules is performed at Los Alamos National Laboratory (LANL) on an automated, digitally-controlled welding system. Baseline design considerations for system automation and strategies employed to maximize process yield, improve process consistency, and generate required quality assurance information are discussed. Design of the automated girth welding system was driven by a number of factors which militated for precise parametric control and data acquisition. Foremost among these factors was the extraordinary value of the capsule components. In addition, DOE order 5700.6B, which took effect on 23 Sep. 1986, required that all operations adhere to strict levels of process quality assurance. A detailed technical specification for the GPHS welding system was developed on the basis of a joint LANL/Westinghouse Savannah River Company (WSRC) design effort. After a competitive bidding process, Jetline Engineering, Inc., of Irvine, California, was selected as the system manufacturer. During the period over which four identical welding systems were fabricated, very close liason was maintained between the LANL/WSRC technical representatives and the vendor. The level of rapport was outstanding, and the end result was the 1990 delivery of four systems that met or exceeded all specification requirements.

  3. Integrating microprobe laboratory automation with high speed data acquisition and analysis

    NASA Astrophysics Data System (ADS)

    Moloney, G. R.; O'Brien, P. M.; Saint, A.; Witham, L.; Sakalleriou, A.; Bettiol, A.; Legge, G. J. F.

    1995-09-01

    We are developing a laboratory and beam line control system. The MpControl system utilises all the flexibility and power of a computer network. Target stages, power supplies, Faraday cups, beam monitors, event counters, etc. can all be controlled by any of a number of computers in the laboratory. Software on each of these computers allows control, monitoring and display of the state of the beam line, accelerator and target manipulation stage. The entire system may be simultaneously controlled from any computer terminal on the network. The system has the potential to allow a user to manipulate the target stage from the beam control room, or to adjust accelerator parameters from the target chamber at the end of the beam line. The system has been designed to be easily transportable across computer platforms, currently with support for UNIX, X-Windows and MS-DOS. We believe this is a critical factor in a world of rapidly advancing computer and instrumentation hardware systems. The system has been designed to integrate with the MpSys data acquisition system.

  4. Digital control and data acquisition for high-value GTA welding

    SciTech Connect

    George, T.G.; Franco-Ferreira, E.A.

    1993-10-01

    Electric power for the Cassini space probe wig be provided by radioisotope thermoelectric generators (RTGs) thermally driven by General-Purpose Heat Source (GPHS) modules. Each GPHS module contains four, 150-g, pellets of {sup 238}PuO{sub 2}, and each of the four pellets is encapsulated within a thin-wall iridium-alloy shell. GTA girth welding of these capsules is performed at Los Alamos National Laboratory (LANL) on an automated, digitally-controlled welding system. This paper discusses baseline design considerations for system automation and strategies employed to maximize process yield, improve process consistency, and generate required quality assurance information. Design of the automated girth welding system was driven by a number of factors which militated for precise parametric control and data acquisition. Foremost among these factors was the extraordinary value of the capsule components. In addition, DOE order 5700.6B, which took effect on 23 September 1986, required that all operations adhere to strict levels of process quality assurance. A detailed technical specification for the GPHS welding system was developed on the basis of a joint Lanl/Westinghouse Savannah River Company (WSRC) design effort. After a competitive bidding process, Jetline Engineering, Inc., of Irvine, California, was selected as the system manufacturer. During the period over which four identical welding systems were fabricated, very close liason was maintained between the LANL/WSRC technical representatives and the vendor. The level of rapport was outstanding, and the end result was the 1990 delivery of four systems that met or exceeded all specification requirements.

  5. Whole-body magnetic resonance imaging featuring moving table continuous data acquisition with high-precision position feedback.

    PubMed

    Zenge, Michael O; Ladd, Mark E; Vogt, Florian M; Brauck, Katja; Barkhausen, Joerg; Quick, Harald H

    2005-09-01

    A novel setup for whole-body MR imaging with moving table continuous data acquisition has been developed and evaluated. The setup features a manually positioned moving table platform with integrated phased-array surface radiofrequency coils. A high-precision laser position sensor was integrated into the system to provide real-time positional data that were used to compensate for nonlinear manual table translation. This setup enables continuous 2D and 3D whole-body data acquisition during table movement with surface coil image quality. The concept has been successfully evaluated with whole-body steady-state free precession (TrueFISP) anatomic imaging in five healthy volunteers. Seamless coronal and sagittal slices of continually acquired whole-body data during table movement were accurately reconstructed. The proposed strategy is potentially useful for a variety of applications, including whole-body metastasis screening, whole-body MR angiography, large field-of-view imaging in short bore systems, and for moving table applications during MR-guided interventions.

  6. Neural convergence for language comprehension and grammatical class production in highly proficient bilinguals is independent of age of acquisition.

    PubMed

    Consonni, Monica; Cafiero, Riccardo; Marin, Dario; Tettamanti, Marco; Iadanza, Antonella; Fabbro, Franco; Perani, Daniela

    2013-05-01

    In bilinguals, native (L1) and second (L2) languages are processed by the same neural resources that can be modulated by age of second language acquisition (AOA), proficiency level, and daily language exposure and usage. AOA seems to particularly affect grammar processing, where a complete neural convergence has been shown only in bilinguals with parallel language acquisition from birth. Despite the fact that proficiency-related neuroanatomical differences have been well documented in language comprehension (LC) and production, few reports have addressed the influence of language exposure. A still unanswered question pertains to the role of AOA, when proficiency is comparably high across languages, with respect to its modulator effects both on LC and production. Here, we evaluated with fMRI during sentence comprehension and verb and noun production tasks, two groups of highly proficient bilinguals only differing in AOA. One group learned Italian and Friulian in parallel from birth, whereas the second group learned Italian between 3 and 6 years. All participants were highly exposed to both languages, but more to Italian than Friulian. The results indicate a complete overlap of neural activations for the comprehension of both languages, not only in bilinguals from birth, but also in late bilinguals. A slightly extra activation in the left thalamus for the less-exposed language confirms that exposure may affect language processing. Noteworthy, we report for the first time that, when proficiency and exposure are kept high, noun and verb production recruit the same neural networks for L1 and L2, independently of AOA. These results support the neural convergence hypothesis.

  7. Results from a data acquisition system prototype project using a switch-based event builder

    SciTech Connect

    Black, D.; Andresen, J.; Barsotti, E.; Baumbaugh, A.; Esterline, D.; Knickerbocker, K.; Kwarciany, R.; Moore, G.; Patrick, J.; Swoboda, C.; Treptow, K.; Trevizo, O.; Urish, J.; VanConant, R.; Walsh, D. ); Bowden, M.; Booth, A. ); Cancelo, G. )

    1991-11-01

    A prototype of a high bandwidth parallel event builder has been designed and tested. The architecture is based on a simple switching network and is adaptable to a wide variety of data acquisition systems. An eight channel system with a peak throughput of 160 Megabytes per second has been implemented. It is modularly expandable to 64 channels (over one Gigabyte per second). The prototype uses a number of relatively recent commercial technologies, including very high speed fiber-optic data links, high integration crossbar switches and embedded RISC processors. It is based on an open architecture which permits the installation of new technologies with little redesign effort. 5 refs., 6 figs.

  8. Very broad gain bandwidth parametric amplification in nonlinear crystals at critical wavelength degeneracy.

    PubMed

    Dabu, R

    2010-05-24

    Gain spectra were calculated at critical wavelength degeneracy (CWD) in a collinear phase-matching geometry optical parametric amplification (OPA) process. The frequency bandwidth available through CWD-OPA is broader compared to the gain bandwidth obtained by the non-collinear OPA geometry. A solution for very broad bandwidth chirped pulse amplification based on partially deuterated DKDP (P-DKDP) crystals, pumped by pulsed green lasers, is proposed. 1.38x10(14) Hz frequency bandwidth and peak intensity gain G approximately 62 were calculated in a 5-mm long 58% deuterated DKDP crystal, pumped by 527-nm wavelength at 64-GW/cm2 intensity. Parametric amplification at CWD in few-mm thin P-DKDP crystals, pumped by picosecond pulses of nearly 100-GW/cm2 intensity, possesses a true potential for generating high energy laser pulses compressible to one-cycle duration.

  9. Stimulated Brillouin scattering gain bandwidth reduction and applications in microwave photonics and optical signal processing

    NASA Astrophysics Data System (ADS)

    Preussler, Stefan; Schneider, Thomas

    2016-03-01

    Stimulated Brillouin scattering (SBS) is one of the most dominant nonlinear effects in standard single-mode fibers and its unique spectral characteristics, especially the narrow bandwidth, enable many different applications. Most of the applications would benefit from a narrower bandwidth. Different methods for the bandwidth reduction of SBS in optical fibers are presented and discussed. A bandwidth reduction down to 17% of the natural gain can be achieved by the superposition of the gain with two losses or the utilization of a multistage system. Furthermore, applications in the field of microwave photonics and optical signal processing like high-resolution spectroscopy of communication signals, the storage of optical data packets as well as the processing of frequency combs including generation of millimeter waves and ideal sinc-shaped Nyquist pulses are presented.

  10. 47 CFR 2.1049 - Measurements required: Occupied bandwidth.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Measurements required: Occupied bandwidth. 2.1049 Section 2.1049 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL FREQUENCY ALLOCATIONS... Certification § 2.1049 Measurements required: Occupied bandwidth. The occupied bandwidth, that is the...

  11. Dedicated 4πβ (LS)-γ (HPGe) digital coincidence system based on synchronous high-speed multichannel data acquisition

    NASA Astrophysics Data System (ADS)

    Chen, Ji-Feng; Song, Ke-Zhu; Liu, Jia-Cheng

    2016-03-01

    A dedicated 4πβ (LS) -γ (HPGe) digital coincidence system with five acquisition channels has been developed. Three ADC acquisition channels with an acquisition resolution of 8 bits and acquisition rate of 1 GSPS are utilized to collect the signals from three PMTs which are used to detect β decay, and two acquisition channels with an acquisition resolution of 16 bits and acquisition rate of 50 MSPS are utilized to collect the signals from high-purity germanium (HPGe), which is used to detect γ decay. In order to increase the accuracy of the coincidence system, all five acquisition channels are synchronous within 500 ps. The data collected by the five acquisition channels will be transmitted to the host PC through a PCI bus and saved as a file. Off-line software is utilized for the 4πβ (LS) -γ (HPGe) coincidence and data analysis as needed in practical applications. Tests of the system show that system can record pulse signals from 4πβ (LS) -γ (HPGe) synchronously for further coincidence calculation and the highest coincidence rate of the system is 20 K/s, which is sufficient for most applications. Compared with traditional coincidence modules like MAC3, the digital coincidence system has a higher flexibility of coincidence algorithm. In addition, due to the use of ADC, the structure of the coincidence system is simplified. This paper introduces the design of the hardware, the synchronization method and the test results of this system. Supported by National Metrology Institute of China

  12. AIROscope stellar acquisition

    NASA Technical Reports Server (NTRS)

    Deboo, G. J.; Parra, G. T.; Hedlund, R. C.

    1974-01-01

    The acquisition system which operates in conjunction with a balloon-borne TV system, boresighted to a telescope is described. It has two main functions, a star field monitor and an offset star tracker. The design of the system was strongly influenced by the TV camera, which uses the same interlaced scanning system as is employed in commercial television broadcasting. To reduce power and bandwidth requirements, the star field information transmitted in our system consists only of the horizontal and vertical coordinates of each star and its brightness. As a star field monitor the system provides video thresholding, camera blemish suppression, coordinate digitization in 3 axes, circuity to recognize as single star the dispersed video signals resulting from one star overlapping adjacent scanning lines and storage of all signals for readout by the telemetry at appropriate times.

  13. Bandwidth of non-contact vital sign detection with a noise suppression phase locked loop

    NASA Astrophysics Data System (ADS)

    Xia, Zongyang; Zhang, Ying

    2016-04-01

    In a dual-carrier vital sign detection system, we have designed a noise suppression scheme that uses phase locked loop (PLL) to automatically suppress the noise induced by range correlation and transmission paths. The system uses two microwave carriers at 5.6 and 5.68 GHz generated by two phase locked signal generators to extract the noise and vital sign respectively. The feedback microwave signals are mixed with local 5.68-GHz signal to transfer to the vial sign signal and low frequency intermediate frequency (IF) signal. When the IF signal corresponding to 5.68 GHz microwave signal is locked to a highly stable low noise reference, the noises of IF signal and vital sign signal are suppressed as their corresponding microwave signals are highly correlated. In this system, the noise suppression performance is related to the bandwidth of the PLL, which needs to be carefully designed. Through the theoretical analysis, initial bandwidth is chosen to be 200 Hz. Then the charge pump current is changed to adjust the bandwidth and the corresponding noise suppression performance is evaluated using experiments. The results show the system with a charge pump current 0.625 mA, which corresponds to about 50 Hz bandwidth, exhibits a better noise performance. In addition, at different bandwidth, the vital sign detection system is compared with a design scheme with unlocked PLL and demonstrates superior performance at all bandwidths.

  14. Spin-torque diode with tunable sensitivity and bandwidth by out-of-plane magnetic field

    NASA Astrophysics Data System (ADS)

    Li, X.; Zheng, C.; Zhou, Y.; Kubota, H.; Yuasa, S.; Pong, Philip W. T.

    2016-06-01

    Spin-torque diodes based on nanosized magnetic tunnel junctions are novel microwave detectors with high sensitivity and wide frequency bandwidth. While previous reports mainly focus on improving the sensitivity, the approaches to extend the bandwidth are limited. This work experimentally demonstrates that through optimizing the orientation of the external magnetic field, wide bandwidth can be achieved while maintaining high sensitivity. The mechanism of the frequency- and sensitivity-tuning is investigated through analyzing the dependence of resonant frequency and DC voltage on the magnitude and the tilt angle of hard-plane magnetic field. The frequency dependence is qualitatively explicated by Kittel's ferromagnetic resonance model. The asymmetric resonant frequency at positive and negative magnetic field is verified by the numerical simulation considering the in-plane anisotropy. The DC voltage dependence is interpreted through evaluating the misalignment angle between the magnetization of the free layer and the reference layer. The tunability of the detector performance by the magnetic field angle is evaluated through characterizing the sensitivity and bandwidth under 3D magnetic field. The frequency bandwidth up to 9.8 GHz or maximum sensitivity up to 154 mV/mW (after impedance mismatch correction) can be achieved by tuning the angle of the applied magnetic field. The results show that the bandwidth and sensitivity can be controlled and adjusted through optimizing the orientation of the magnetic field for various applications and requirements.

  15. 47 CFR 101.109 - Bandwidth.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ..., consistent with efficient use of the spectrum and good engineering practice, except that Type B, damped-wave... communications. Frequency band (MHz) Maximum authorized bandwidth 928 to 929 25 kHz 1,5,6 932 to 932.5, 941 to 941.5 12.5 kHz 1,5,6 932.5 to 935, 941.5 to 944 200 kHz 1 952 to 960 200 KHz 1,5,6 1,850 to 1,990...

  16. 47 CFR 101.109 - Bandwidth.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... good engineering practice, except that Type B, damped-wave emission will not be authorized. (c) The... authorized bandwidth 928 to 929 25 kHz 1 5 6 932 to 932.5, 941 to 941.5 12.5 kHz 1 5 6 932.5 to 935, 941.5 to 944 200 kHz 1 952 to 960 200 KHz 1 5 6 1,850 to 1,990 10 MHz 1 2,110 to 2,130 3.5 MHz 2,130 to...

  17. 47 CFR 101.109 - Bandwidth.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... good engineering practice, except that Type B, damped-wave emission will not be authorized. (c) The... authorized bandwidth 928 to 929 25 kHz 1 5 6 932 to 932.5, 941 to 941.5 12.5 kHz 1 5 6 932.5 to 935, 941.5 to 944 200 kHz 1 952 to 960 200 KHz 1 5 6 1,850 to 1,990 10 MHz 1 2,110 to 2,130 3.5 MHz 2,130 to...

  18. Confocal microscopy via multimode fibers: fluorescence bandwidth

    NASA Astrophysics Data System (ADS)

    Loterie, Damien; Psaltis, Demetri; Moser, Christophe

    2016-03-01

    We recently described a method for confocal reflection imaging through fibers, as a way to increase contrast when imaging unstained biological specimens. Using a transmission matrix, focused spots can be created at the distal end of a fiber. The backscattered field coming back from the sample can be filtered using optical correlation to obtain spatial selectivity in the detection. In this proceedings article, we briefly review the working principle of this method, and we discuss how the scheme could be adapted to confocal fluorescence imaging. In particular, we show simulations of the achievable detection bandwidth when using step-index multimode fibers as imaging devices.

  19. Flexible attosecond beamline for high harmonic spectroscopy and XUV/near-IR pump probe experiments requiring long acquisition times

    SciTech Connect

    Weber, S. J. Manschwetus, B.; Billon, M.; Bougeard, M.; Breger, P.; Géléoc, M.; Gruson, V.; Lin, N.; Ruchon, T.; Salières, P.; Carré, B.

    2015-03-15

    We describe the versatile features of the attosecond beamline recently installed at CEA-Saclay on the PLFA kHz laser. It combines a fine and very complete set of diagnostics enabling high harmonic spectroscopy (HHS) through the advanced characterization of the amplitude, phase, and polarization of the harmonic emission. It also allows a variety of photo-ionization experiments using magnetic bottle and COLTRIMS (COLd Target Recoil Ion Momentum Microscopy) electron spectrometers that may be used simultaneously, thanks to a two-foci configuration. Using both passive and active stabilization, special care was paid to the long term stability of the system to allow, using both experimental approaches, time resolved studies with attosecond precision, typically over several hours of acquisition times. As an illustration, applications to multi-orbital HHS and electron-ion coincidence time resolved spectroscopy are presented.

  20. Variable bandwidth broadcasting protocol for video-on-demand

    NASA Astrophysics Data System (ADS)

    Paris, Jehan-Francois; Long, Darrell D. E.

    2003-01-01

    We present the first broadcasting protocol that can alter the number of channels allocated to a given video without inconveniencing the viewer and without causing any temporary bandwidth surge. Our variable bandwidth broadcasting (VBB) protocol assigns to each video a minimum number of channels whose bandwidths are all equal to the video consumption rate. Additional channels can be assigned to the video at any time to reduce the customer waiting time or retaken to free server bandwidth. The cost of this additional flexibility is quite reasonable as the bandwidth requirements of our VBB fall between those of the fast broadcasting protocol and the new pagoda broadcasting protocol.

  1. Detection of latent fingerprints using high-resolution 3D confocal microscopy in non-planar acquisition scenarios

    NASA Astrophysics Data System (ADS)

    Kirst, Stefan; Vielhauer, Claus

    2015-03-01

    In digitized forensics the support of investigators in any manner is one of the main goals. Using conservative lifting methods, the detection of traces is done manually. For non-destructive contactless methods, the necessity for detecting traces is obvious for further biometric analysis. High resolutional 3D confocal laser scanning microscopy (CLSM) grants the possibility for a detection by segmentation approach with improved detection results. Optimal scan results with CLSM are achieved on surfaces orthogonal to the sensor, which is not always possible due to environmental circumstances or the surface's shape. This introduces additional noise, outliers and a lack of contrast, making a detection of traces even harder. Prior work showed the possibility of determining angle-independent classification models for the detection of latent fingerprints (LFP). Enhancing this approach, we introduce a larger feature space containing a variety of statistical-, roughness-, color-, edge-directivity-, histogram-, Gabor-, gradient- and Tamura features based on raw data and gray-level co-occurrence matrices (GLCM) using high resolutional data. Our test set consists of eight different surfaces for the detection of LFP in four different acquisition angles with a total of 1920 single scans. For each surface and angles in steps of 10, we capture samples from five donors to introduce variance by a variety of sweat compositions and application influences such as pressure or differences in ridge thickness. By analyzing the present test set with our approach, we intend to determine angle- and substrate-dependent classification models to determine optimal surface specific acquisition setups and also classification models for a general detection purpose for both, angles and substrates. The results on overall models with classification rates up to 75.15% (kappa 0.50) already show a positive tendency regarding the usability of the proposed methods for LFP detection on varying surfaces in non

  2. SPLASSH: Open source software for camera-based high-speed, multispectral in-vivo optical image acquisition

    PubMed Central

    Sun, Ryan; Bouchard, Matthew B.; Hillman, Elizabeth M. C.

    2010-01-01

    Camera-based in-vivo optical imaging can provide detailed images of living tissue that reveal structure, function, and disease. High-speed, high resolution imaging can reveal dynamic events such as changes in blood flow and responses to stimulation. Despite these benefits, commercially available scientific cameras rarely include software that is suitable for in-vivo imaging applications, making this highly versatile form of optical imaging challenging and time-consuming to implement. To address this issue, we have developed a novel, open-source software package to control high-speed, multispectral optical imaging systems. The software integrates a number of modular functions through a custom graphical user interface (GUI) and provides extensive control over a wide range of inexpensive IEEE 1394 Firewire cameras. Multispectral illumination can be incorporated through the use of off-the-shelf light emitting diodes which the software synchronizes to image acquisition via a programmed microcontroller, allowing arbitrary high-speed illumination sequences. The complete software suite is available for free download. Here we describe the software’s framework and provide details to guide users with development of this and similar software. PMID:21258475

  3. Acquisition performance of various QPSK carrier tracking loops

    NASA Astrophysics Data System (ADS)

    Hinedi, S.; Shah, B.

    1992-09-01

    The frequency and phase acquisition performance of three quadrature phase shift keying (QPSK) carrier tracking loops, the MAP estimation loop, the Costas crossover loop, and the generalized Costas loop, is described. Acquisition time and probability of acquisition as a function of both loop signal-to-noise ratio and frequency offset to loop bandwidth ratio are obtained via computer simulations for type II and III loops. It is shown that the MAP loop, which results in the smallest squaring loss for all signal-to-noise ratios, is sometimes outperformed by the other two loops in terms of acquisition time and acquisition probability.

  4. Acquisition performance of various QPSK carrier tracking loops

    NASA Technical Reports Server (NTRS)

    Hinedi, S.; Shah, B.

    1992-01-01

    The frequency and phase acquisition performance of three quadrature phase shift keying (QPSK) carrier tracking loops, the MAP estimation loop, the Costas crossover loop, and the generalized Costas loop, is described. Acquisition time and probability of acquisition as a function of both loop signal-to-noise ratio and frequency offset to loop bandwidth ratio are obtained via computer simulations for type II and III loops. It is shown that the MAP loop, which results in the smallest squaring loss for all signal-to-noise ratios, is sometimes outperformed by the other two loops in terms of acquisition time and acquisition probability.

  5. Tunable pulsed narrow bandwidth light source

    DOEpatents

    Powers, Peter E.; Kulp, Thomas J.

    2002-01-01

    A tunable pulsed narrow bandwidth light source and a method of operating a light source are provided. The light source includes a pump laser, first and second non-linear optical crystals, a tunable filter, and light pulse directing optics. The method includes the steps of operating the pump laser to generate a pulsed pump beam characterized by a nanosecond pulse duration and arranging the light pulse directing optics so as to (i) split the pulsed pump beam into primary and secondary pump beams; (ii) direct the primary pump beam through an input face of the first non-linear optical crystal such that a primary output beam exits from an output face of the first non-linear optical crystal; (iii) direct the primary output beam through the tunable filter to generate a sculpted seed beam; and direct the sculpted seed beam and the secondary pump beam through an input face of the second non-linear optical crystal such that a secondary output beam characterized by at least one spectral bandwidth on the order of about 0.1 cm.sup.-1 and below exits from an output face of the second non-linear optical crystal.

  6. Coherence bandwidth loss in transionospheric radio propagation

    NASA Technical Reports Server (NTRS)

    Rino, C. L.; Gonzalez, V. H.; Hessing, A. R.

    1980-01-01

    In this report a theoretical model is developed that predicts the single-point, two-frequency coherence function for transionospheric radio waves. The theoretical model is compared to measured complex frequency correlation coefficients using data from the seven equispaced, phase-coherent UHF signals transmitted by the Wideband satellite. The theory and data are in excellent agreement. The theory is critically dependent upon the power-law index, and the frequency coherence data clearly favor the comparatively small spectral indices that have been consistently measured from the wideband satellite phase data. A model for estimating the pulse delay jitter induced by the coherence bandwidth loss is also developed and compared with the actual delay jitter observed on synthesized pulses obtained from the Wideband UFH comb. The results are in good agreement with the theory. The results presented in this report, which are based on an asymptotic theory, are compared with the more commonly used quadratic theory. The model developed and validated in this report can be used to predict the effects of coherence bandwidth loss in disturbed nuclear environments. Simple formulas for the resultant pulse delay jitter are derived that can be used in predictive codes.

  7. A comparison of high-speed links, their commercial support and ongoing R D activities

    SciTech Connect

    Gonzalez, H.L.; Barsotti, E. ); Zimmermann, S. Rio Grande do Sul Univ., Porto Alegre, RS ); Nomachi, M.; Sasaki, O. )

    1992-10-01

    Technological advances and a demanding market have forced the development of higher bandwidth communication standards for networks, data links and busses. Most of these emerging standards are gathering enough momentum that their widespread availability and lower prices are anticipated. The hardware and software that support the physical media for most of these links is currently available, allowing the user community to implement fairly high-bandwidth data links and networks with commercial components. Also, switches needed to support these networks are available or being developed. The commercial suppose of high-bandwidth data links, networks and switching fabrics provides a powerful base for the implementation of high-bandwidth data acquisition systems. A large data acquisition system like the one for the Solenoidal Detector Collaboration (SDC) at the SSC can benefit from links and networks that support an integrated systems engineering approach, for initialization, downloading, diagnostics, monitoring, hardware integration and event data readout. The issue that our current work addresses is the possibility of having a channel/network that satisfies the requirements of an integrated data acquisition system. In this paper we present a brief description of high-speed communication links and protocols that we consider of interest for high energy physic High Performance Parallel Interface (HIPPI). Serial HIPPI, Fibre Channel (FC) and Scalable Coherent Interface (SCI). In addition, the initial work required to implement an SDC-like data acquisition system is described.

  8. A comparison of high-speed links, their commercial support and ongoing R&D activities

    SciTech Connect

    Gonzalez, H.L.; Barsotti, E.; Zimmermann, S. |; Nomachi, M.; Sasaki, O.

    1992-10-01

    Technological advances and a demanding market have forced the development of higher bandwidth communication standards for networks, data links and busses. Most of these emerging standards are gathering enough momentum that their widespread availability and lower prices are anticipated. The hardware and software that support the physical media for most of these links is currently available, allowing the user community to implement fairly high-bandwidth data links and networks with commercial components. Also, switches needed to support these networks are available or being developed. The commercial suppose of high-bandwidth data links, networks and switching fabrics provides a powerful base for the implementation of high-bandwidth data acquisition systems. A large data acquisition system like the one for the Solenoidal Detector Collaboration (SDC) at the SSC can benefit from links and networks that support an integrated systems engineering approach, for initialization, downloading, diagnostics, monitoring, hardware integration and event data readout. The issue that our current work addresses is the possibility of having a channel/network that satisfies the requirements of an integrated data acquisition system. In this paper we present a brief description of high-speed communication links and protocols that we consider of interest for high energy physic High Performance Parallel Interface (HIPPI). Serial HIPPI, Fibre Channel (FC) and Scalable Coherent Interface (SCI). In addition, the initial work required to implement an SDC-like data acquisition system is described.

  9. MATLAB implementation of a dynamic clamp with bandwidth of >125 kHz capable of generating I Na at 37 °C.

    PubMed

    Clausen, Chris; Valiunas, Virginijus; Brink, Peter R; Cohen, Ira S

    2013-04-01

    We describe the construction of a dynamic clamp with a bandwidth of >125 kHz that utilizes a high-performance, yet low-cost, standard home/office PC interfaced with a high-speed (16 bit) data acquisition module. High bandwidth is achieved by exploiting recently available software advances (code-generation technology and optimized real-time kernel). Dynamic-clamp programs are constructed using Simulink, a visual programming language. Blocks for computation of membrane currents are written in the high-level MATLAB language; no programming in C is required. The instrument can be used in single- or dual-cell configurations, with the capability to modify programs while experiments are in progress. We describe an algorithm for computing the fast transient Na(+) current (I Na) in real time and test its accuracy and stability using rate constants appropriate for 37 °C. We then construct a program capable of supplying three currents to a cell preparation: I Na, the hyperpolarizing-activated inward pacemaker current (I f) and an inward-rectifier K(+) current (I K1). The program corrects for the IR drop due to electrode current flow and also records all voltages and currents. We tested this program on dual patch-clamped HEK293 cells where the dynamic clamp controls a current-clamp amplifier and a voltage-clamp amplifier controls membrane potential, and current-clamped HEK293 cells where the dynamic clamp produces spontaneous pacing behavior exhibiting Na(+) spikes in otherwise passive cells.

  10. High-Speed Color Video System For Data Acquisition At 200 Fields Per Second

    NASA Astrophysics Data System (ADS)

    Holzapfel, C.

    1982-02-01

    Nac Incorporated has recently introduced a new high speed color video system which employs a standard VHS color video cassette. Playback can be accomplished on either the HSV-200 or on a standard VHS video recorder/playback unit, such as manufactured by JVC or Panasonic.

  11. MONSOON: Image Acquisition System or "Pixel Server"

    NASA Astrophysics Data System (ADS)

    Starr, Barry M.; Buchholz, Nick C.; Rahmer, Gustavo; Penegor, Gerald; Schmidt, Ricardo E.; Warner, Michael; Merrill, Michael; Claver, Charles F.; Ho, Y.; Chopra, K. N.; Shroff, C.; Shroff, D.

    2003-03-01

    The MONSOON Image Acquisition System has been designed to meet the need for scalable, multichannel, high-speed image acquisition required for the next-generation optical and infared detectors and mosaic projects currently under development at NOAO as described in other papers at this proceeding such as ORION, NEWFIRM, QUOTA, ODI and LSST. These new systems with their large scale (64 to 2000 channels) and high performance (up to 1Gbyte/s) raise new challenges in terms of communication bandwidth, data storage and data processing requirements which are not adequately met by existing astronomical controllers. In order to meet this demand, new techniques for not only a new detector controller, but rather a new image acquisition architecture, have been defined. These extremely large scale imaging systems also raise less obvious concerns in previously neglected areas of controller design such as physical size and form factor issues, power dissipation and cooling near the telescope, system assembly/test/ integration time, reliability, and total cost of ownership. At NOAO we have taken efforts to look outside of the astronomical community for solutions found in other disciplines to similar classes of problems. A large number of the challenges raised by these system needs are already successfully being faced in other areas such as telecommunications, instrumentation and aerospace. Efforts have also been made to use true commercial off the shelf (COTS) system elements, and find truly technology independent solutions for a number of system design issues whenever possible. The Monsoon effort is a full-disclosure development effort by NOAO in collaboration with the CARA ASTEROID project for the benefit of the astronomical community.

  12. Notes on acquisition of high-resolution seismic profiles in southern Puget Sound, Washington

    USGS Publications Warehouse

    Snavely, P.D., Jr.; Gower, H.D.; Yount, J.C.; Pearl, J.E.; Tagg, A.R.; Lee, J.W.; Lander, D.L.

    1978-01-01

    Approximately 275 km of high-resolution seismic reflection profiles were obtained in Puget Sound, Washington from the U.S. Geological Survey's research vessel DON J. MILLER from January 13 through 19, 1976. These data, recorded on microfilm, were obtained to provide information on the thickness and distribution of Quaternary deposits, to identify folds and faults that deform them, and to provide a basis for assessing geological environmental hazards.

  13. Simulations with SCI as a data carrier in data acquisition systems

    SciTech Connect

    Kristiansen, E.H. Univ. of Oslo . Dept. of Physics); Bothner, J.W.; Hulaas, T.I.; Skaali, T.B. ); Rongved, E. )

    1994-02-01

    Detailed simulations of processor networks based on the Scalable Coherent Interface (SCI) show that SCI is suitable as data carrier in data acquisition systems where the total bandwidth need is in the multi GBytes/s range and a low latency is required. The objective of these simulations was to find topologies with low latency and high bandwidth, but also with the cost of implementation in mind. A ring-to-ring bridge has been used as the building element for the networks. The simulations have been performed on regular k-ary n-cubes type topologies from a few tens of nodes and up to about 500 nodes under different load conditions. Among the parameters which has been manipulated in the simulations are the number of nodes, topology structure, number of outstanding requests and load in the system.

  14. High-contrast 3D image acquisition using HiLo microscopy with an electrically tunable lens

    NASA Astrophysics Data System (ADS)

    Philipp, Katrin; Smolarski, André; Fischer, Andreas; Koukourakis, Nektarios; Stürmer, Moritz; Wallrabe, Ulricke; Czarske, Jürgen

    2016-04-01

    We present a HiLo microscope with an electrically tunable lens for high-contrast three-dimensional image acquisition. HiLo microscopy combines wide field and speckled illumination images to create optically sectioned images. Additionally, the depth-of-field is not fixed, but can be adjusted between wide field and confocal-like axial resolution. We incorporate an electrically tunable lens in the HiLo microscope for axial scanning, to obtain three-dimensional data without the need of moving neither the sample nor the objective. The used adaptive lens consists of a transparent polydimethylsiloxane (PDMS) membrane into which an annular piezo bending actuator is embedded. A transparent fluid is filled between the membrane and the glass substrate. When actuated, the piezo generates a pressure in the lens which deflects the membrane and thus changes the refractive power. This technique enables a large tuning range of the refractive power between 1/f = (-24 . . . 25) 1/m. As the NA of the adaptive lens is only about 0.05, a fixed high-NA lens is included in the setup to provide high resolution. In this contribution, the scan properties and capabilities of the tunable lens in the HiLo microscope are analyzed. Eventually, exemplary measurements are presented and discussed.

  15. Spatially encoded pulse sequences for the acquisition of high resolution NMR spectra in inhomogeneous fields

    NASA Astrophysics Data System (ADS)

    Shapira, Boaz; Frydman, Lucio

    2006-09-01

    We have recently proposed a protocol for retrieving nuclear magnetic resonance (NMR) spectra based on a spatially-dependent encoding of the MR interactions. It has also been shown that the spatial selectivity with which spins are manipulated during such encoding opens up new avenues towards the removal of magnetic field inhomogeneities; not by demanding extreme Bo field uniformities, but rather by compensating for the dephasing effects introduced by the field distribution at a radiofrequency excitation and/or refocusing level. The present study discusses in further detail a number of strategies deriving from this principle, geared at acquiring both uni- as well as multi-dimensional spectroscopic data at high resolution conditions. Different variants are presented, tailored according to the relative sensitivity and chemical nature of the spin system being explored. In particular a simple multi-scan experiment is discussed capable of affording substantial improvements in the spectral resolution, at nearly no sensitivity or scaling penalties. This new compensation scheme is therefore well-suited for the collection of high-resolution data in low-field systems possessing limited signal-to-noise ratios, where magnetic field heterogeneities might present a serious obstacle. Potential areas of applications of these techniques include high-field in vivo NMR studies in regions near tissue/air interfaces, clinical low field MR spectroscopy on relatively large off-center volumes difficult to shim, and ex situ NMR. The principles of the different compensation methods are reviewed and experimentally demonstrated for one-dimensional inhomogeneities; further improvements and extensions are briefly discussed.

  16. Traveling young injection drug users at high risk for acquisition and transmission of viral infections

    PubMed Central

    Hahn, Judith A.; Page-Shafer, Kimberly; Ford, Jamye; Paciorek, Alan; Lum, Paula J.

    2008-01-01

    Background: Young injection drug users (IDU) are highly mobile. It is not known how mobility affects their risk of acquiring and transmitting viral infections. Methods: We conducted a cross-sectional study of young (under age 30) IDU in San Francisco (2004-2006). Participants completed a semi-structured interview and testing for hepatitis B virus (HBV), hepatitis C virus (HCV) and HIV infection. We examined whether travel was independently associated with drug, alcohol, sexual risk behaviors, and infection status, after adjusting for demographic characteristics and years injecting. Results: Two-thirds (62%) reported past (3 months) travel outside of San Francisco (n=355). Travelers, as compared to non-travelers, were more likely to be under age 20, female, and planned to leave San Francisco in the coming months. Travel was independently associated with heavy alcohol consumption, drinking alcohol until blackout, poly-substance use, more sexual and injecting partners, and receptive needle/syringe sharing, sharing drug preparation equipment, backloading syringes, and pooling money to buy drugs. In an analysis of interactions with travel, younger travelers were more likely to be HCV positive than younger non-travelers. Discussion: Traveling young IDU are at exceptionally high risk for acquiring and transmitting viral infections, while their mobility makes it challenging to effectively deliver interventions. PMID:17980513

  17. Using hardware-assisted geometric hashing for high-speed target acquisition and guidance

    NASA Astrophysics Data System (ADS)

    Pears, Arnold N.; Pissaloux, Edwige E.

    1997-06-01

    Geometric hashing provides a reliable and transformation independent representation of a target. The characterization of a target object is obtained by establishing a vector basis relative to a number of interest points unique to the target. The number of basis points required is a function of the dimensionality of the environment in which the technique is being used. This basis is used to encode the other points in the object constructing a highly general (transformation independent) representation of the target. The representation is invariant under both affine and geometric transformations of the target interest points. Once a representation of the target has been constructed a simple voting algorithm can be used to examine sets of interest points extracted from subsequent image in order to determine the possible presence and location of that target. Once an instance of the object has been located further computation can be undertaken to determine its scale, orientation, and deformation due to changes in the parameters related to the viewpoint. This information can be further analyzed to provide guidance. This paper discusses the complexity measures associated with task division and target image processing using geometric hashing. These measures are used to determine the areas which will most benefit from hardware assistance, and possible parallelism. These issues are discussed in the context of an architecture design, and a high speed (hardware assisted) geometric hashing approach to target recognition is proposed.

  18. PEP Deployment and Bandwidth Management Issues

    NASA Astrophysics Data System (ADS)

    Younghusband, Charles; Slade, Peter; Weaver, Jeff

    This paper will discuss current deployment scenarios for Performance Enhancement Proxies (PEP) technologies in broadband satellite access systems from the perspective of one PEP technology provider. Recent improvements such as DVB-S2 can provide substantial gains at the link layer. In order to achieve further efficiency gains, the satellite industry is now forced to look elsewhere - namely other layers in the data communications network stack. Satellite terminal manufacturers are now moving beyond basic TCP acceleration techniques to more comprehensive optimization techniques that incorporate advances in data compression and flexibility for more deployment scenarios. Some of the advances for PEP technology are in part due to CPU and memory technology advances, resulting in increasingly affordable access to computing power, allowing PEP manufacturers deliver substantial performance and bandwidth savings gains.

  19. The upgrade for the data acquisition system of the KOTO detector

    NASA Astrophysics Data System (ADS)

    Tecchio, M.; Beechert, J.; Campbell, M.; Huff, M.; Micallef, J.; Rymph, C.; Schamis, H.; Su, S.; Xu, J.

    2016-07-01

    A major upgrade to the KOTO detector data acquisition system based on the ATCA standard is being considered. The ATCA standard provides a natural solution to the current KOTO constraints, including communication between boards and higher input and output bandwidth.

  20. Rapid acquisition of Gigapascal-high-pressure resistance by Escherichia coli.

    PubMed

    Vanlint, Dietrich; Mitchell, Rachael; Bailey, Edward; Meersman, Filip; McMillan, Paul F; Michiels, Chris W; Aertsen, Abram

    2011-01-25

    Pressure and temperature are important environmental variables that influence living systems. However, while they vary over a considerable range on Earth and other planets, it has hardly been addressed how straightforwardly and to what extent cellular life can acquire resistance to extremes of these parameters within a defined genomic context and a limited number of generations. Nevertheless, this is a very pertinent question with respect to the penetration of life in allegedly inhospitable environments. In this study, directed evolution was used to reveal the potential of the nonsporulating and mesophilic model bacterium Escherichia coli to develop the ability to survive exposure to high temperature or pressure. While heat resistance could only marginally be increased, our data show that piezoresistance could readily and reproducibly be extended into the GPa range, thereby greatly exceeding the currently recognized maximum for growth or survival.

  1. High speed, multi-channel, user programmable digital data acquisition system.

    SciTech Connect

    Sabourov, Konstantin; Hennig, Wolfgang; Walby, Mark

    2013-11-18

    As applications for radiation detection become more demanding, and in turn improvements are made in the technology of radiation detection, there is a need for high speed digital detector readout electronics matching these improvements. Specifically, full control over the on-line processing resources of modern digital electronics is desirable so that researchers can develop custom algorithms for special applications.In the proposed effort, the 500 MHz digital readout electronics previously developed by our company will be redesigned to allow user access to the on-line processing resources. In Phase I, the division of online processing into vendor and user firmware sections has been studied on existing hardware. In Phase II, the hardware will be upgraded to better facilitate the division, and the firmware will be restructured into a robust vendor logic block (providing standard functions such as host I/O, on-board memory I/O, energy computation, MCA spectra, timestamps, waveform capture, run statistics, and triggering and timing) and a user logic block for custom algorithms (with templates and examples for frequently used functions). Investigating several options to divide online processing, it was determined that the most promising approach is to “partition” a single FPGA integrated circuit into a vendor and user section, which is supported in newer devices. The analog front end of the existing electronics proved suitable for most applications, in particular high rate measurements with germanium detectors. The design architecture for new electronics was developed, combining one of the new FPGA device with the analog front end.

  2. Improving microwave antenna gain and bandwidth with phase compensation metasurface

    SciTech Connect

    Chen, Ke; Yang, Zhongjie; Feng, Yijun Zhu, Bo; Zhao, Junming; Jiang, Tian

    2015-06-15

    Metasurface, as a planar version of artificial metamaterial, provide an effective way to manipulate electromagnetic wave propagation. Here, we present a transparent metasurface for compensating the out-of-phase radiation from a microstrip patch antenna to improve its radiation gain and bandwidth. Based on the equivalence principle of Huygens’ surface, we propose metasurface composed of both inductive and capacitive resonant elements which could produce high transmission with variable phase characteristics. Such metasurface mounted on a patch antenna can transform the spherical-like phase profile generated from the patch into an in-phase planar one. A prototype antenna has been fabricated and validated the squeezed radiation pattern with suppressed sidelobes as well as enhanced impedance bandwidth due to strong near-field coupling. As operating at around 5.7 GHz, the proposed antenna may have potential application in wireless communication systems especially for point-to-point data transmission. It is believed that the design methodology could also be scaled to other frequency bands such as millimeter or terahertz wave.

  3. Ionospheric Coherence Bandwidth Measurements in the Lower VHF Frequency Range

    NASA Astrophysics Data System (ADS)

    Suszcynsky, D. M.; Light, M. E.; Pigue, M. J.

    2015-12-01

    The United States Department of Energy's Radio Frequency Propagation (RFProp) experiment consists of a satellite-based radio receiver suite to study various aspects of trans-ionospheric signal propagation and detection in four frequency bands, 2 - 55 MHz, 125 - 175 MHz, 365 - 415 MHz and 820 - 1100 MHz. In this paper, we present simultaneous ionospheric coherence bandwidth and S4 scintillation index measurements in the 32 - 44 MHz frequency range collected during the ESCINT equatorial scintillation experiment. 40-MHz continuous wave (CW) and 32 - 44 MHz swept frequency signals were transmitted simultaneously to the RFProp receiver suite from the Reagan Test Site at Kwajalein Atoll in the Marshall Islands (8.7° N, 167.7° E) in three separate campaigns during the 2014 and 2015 equinoxes. Results show coherence bandwidths as small as ~ 1 kHz for strong scintillation (S4 > 0.7) and indicate a high degree of ionospheric variability and irregularity on 10-m spatial scales. Spread-Doppler clutter effects arising from preferential ray paths to the satellite due to refraction off of isolated density irregularities are also observed and are dominant at low elevation angles. The results are compared to previous measurements and available scaling laws.

  4. Progressive raster imagery beyond a means to overcome limited bandwidth

    NASA Astrophysics Data System (ADS)

    Rosenbaum, René; Schumann, Heidrun

    2009-02-01

    Progressive refinement is a well-established approach to overcome bandwidth limitations in mobile environments. One outstanding benefit compared to relates approaches is the provision of meaningful content previews during data transfer or processing. Although highly relevant and useful, however, related literature only addresses the support of this functionality by certain communication stages or proposes systems for specific use cases. No publication is concerned with an abstraction or formalization of progression or takes advantage of its beneficial properties in other application fields. In this publication we want to give a general view to progression, its key concepts, attributes, and common data processing pipeline. Thereby, we abstract from specifics and usage scenarios in order to simplify the development of new algorithms and schemes and to derive guidelines for its general application. To show that progression is also able to solve problems beyond limited bandwidth, this contribution is also concerned with the introduction of new application areas. The novel idea of content-oriented refinement allows emphasizing important image regions by an animated tour-through-the-data. It will also be shown that progressive representations are a very effective means for device adaptation. Both applications are motivated, discussed, and illustrated by different examples.

  5. The Effect of Pulse Shaping QPSK on Bandwidth Efficiency

    NASA Technical Reports Server (NTRS)

    Purba, Josua Bisuk Mubyarto; Horan, Shelia

    1997-01-01

    This research investigates the effect of pulse shaping QPSK on bandwidth efficiency over a non-linear channel. This investigation will include software simulations and the hardware implementation. Three kinds of filters: the 5th order Butterworth filter, the 3rd order Bessel filter and the Square Root Raised Cosine filter with a roll off factor (alpha) of 0.25,0.5 and 1, have been investigated as pulse shaping filters. Two different high power amplifiers, one a Traveling Wave Tube Amplifier (TWTA) and the other a Solid State Power Amplifier (SSPA) have been investigated in the hardware implementation. A significant improvement in the bandwidth utilization (rho) for the filtered data compared to unfiltered data through the non-linear channel is shown in the results. This method promises strong performance gains in a bandlimited channel when compared to unfiltered systems. This work was conducted at NMSU in the Center for Space Telemetering, and Telecommunications Systems in the Klipsch School of Electrical and Computer Engineering Department and is supported by a grant from the National Aeronautics and Space Administration (NASA) NAG5-1491.

  6. Optimal filter bandwidth for pulse oximetry

    NASA Astrophysics Data System (ADS)

    Stuban, Norbert; Niwayama, Masatsugu

    2012-10-01

    Pulse oximeters contain one or more signal filtering stages between the photodiode and microcontroller. These filters are responsible for removing the noise while retaining the useful frequency components of the signal, thus improving the signal-to-noise ratio. The corner frequencies of these filters affect not only the noise level, but also the shape of the pulse signal. Narrow filter bandwidth effectively suppresses the noise; however, at the same time, it distorts the useful signal components by decreasing the harmonic content. In this paper, we investigated the influence of the filter bandwidth on the accuracy of pulse oximeters. We used a pulse oximeter tester device to produce stable, repetitive pulse waves with digitally adjustable R ratio and heart rate. We built a pulse oximeter and attached it to the tester device. The pulse oximeter digitized the current of its photodiode directly, without any analog signal conditioning. We varied the corner frequency of the low-pass filter in the pulse oximeter in the range of 0.66-15 Hz by software. For the tester device, the R ratio was set to R = 1.00, and the R ratio deviation measured by the pulse oximeter was monitored as a function of the corner frequency of the low-pass filter. The results revealed that lowering the corner frequency of the low-pass filter did not decrease the accuracy of the oxygen level measurements. The lowest possible value of the corner frequency of the low-pass filter is the fundamental frequency of the pulse signal. We concluded that the harmonics of the pulse signal do not contribute to the accuracy of pulse oximetry. The results achieved by the pulse oximeter tester were verified by human experiments, performed on five healthy subjects. The results of the human measurements confirmed that filtering out the harmonics of the pulse signal does not degrade the accuracy of pulse oximetry.

  7. Optimal filter bandwidth for pulse oximetry.

    PubMed

    Stuban, Norbert; Niwayama, Masatsugu

    2012-10-01

    Pulse oximeters contain one or more signal filtering stages between the photodiode and microcontroller. These filters are responsible for removing the noise while retaining the useful frequency components of the signal, thus improving the signal-to-noise ratio. The corner frequencies of these filters affect not only the noise level, but also the shape of the pulse signal. Narrow filter bandwidth effectively suppresses the noise; however, at the same time, it distorts the useful signal components by decreasing the harmonic content. In this paper, we investigated the influence of the filter bandwidth on the accuracy of pulse oximeters. We used a pulse oximeter tester device to produce stable, repetitive pulse waves with digitally adjustable R ratio and heart rate. We built a pulse oximeter and attached it to the tester device. The pulse oximeter digitized the current of its photodiode directly, without any analog signal conditioning. We varied the corner frequency of the low-pass filter in the pulse oximeter in the range of 0.66-15 Hz by software. For the tester device, the R ratio was set to R = 1.00, and the R ratio deviation measured by the pulse oximeter was monitored as a function of the corner frequency of the low-pass filter. The results revealed that lowering the corner frequency of the low-pass filter did not decrease the accuracy of the oxygen level measurements. The lowest possible value of the corner frequency of the low-pass filter is the fundamental frequency of the pulse signal. We concluded that the harmonics of the pulse signal do not contribute to the accuracy of pulse oximetry. The results achieved by the pulse oximeter tester were verified by human experiments, performed on five healthy subjects. The results of the human measurements confirmed that filtering out the harmonics of the pulse signal does not degrade the accuracy of pulse oximetry.

  8. Interactive knowledge acquisition tools

    NASA Technical Reports Server (NTRS)

    Dudziak, Martin J.; Feinstein, Jerald L.

    1987-01-01

    The problems of designing practical tools to aid the knowledge engineer and general applications used in performing knowledge acquisition tasks are discussed. A particular approach was developed for the class of knowledge acquisition problem characterized by situations where acquisition and transformation of domain expertise are often bottlenecks in systems development. An explanation is given on how the tool and underlying software engineering principles can be extended to provide a flexible set of tools that allow the application specialist to build highly customized knowledge-based applications.

  9. Reduced phosphatidylinositol 4,5-bisphosphate synthesis impairs inner ear Ca2+ signaling and high-frequency hearing acquisition

    PubMed Central

    Rodriguez, Laura; Simeonato, Elena; Scimemi, Pietro; Anselmi, Fabio; Calì, Bianca; Crispino, Giulia; Ciubotaru, Catalin D.; Bortolozzi, Mario; Ramirez, Fabian Galindo; Majumder, Paromita; Arslan, Edoardo; De Camilli, Pietro; Pozzan, Tullio; Mammano, Fabio

    2012-01-01

    Phosphatidylinositol phosphate kinase type 1γ (PIPKIγ) is a key enzyme in the generation of phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] and is expressed at high levels in the nervous system. Homozygous knockout mice lacking this enzyme die postnatally within 24 h, whereas PIPKIγ+/− siblings breed normally and have no reported phenotype. Here we show that adult PIPKIγ+/− mice have dramatically elevated hearing thresholds for high-frequency sounds. During the first postnatal week we observed a reduction of ATP-dependent Ca2+ signaling activity in cochlear nonsensory cells. Because Ca2+ signaling under these conditions depends on inositol-1,4,5-trisphosphate generation from phospholipase C (PLC)-dependent hydrolysis of PI(4,5)P2, we conclude that (i) PIPKIγ is primarily responsible for the synthesis of the receptor-regulated PLC-sensitive PI(4,5)P2 pool in the cell syncytia that supports auditory hair cells; (ii) spatially graded impairment of this signaling pathway in cochlear nonsensory cells causes a selective alteration in the acquisition of hearing in PIPKIγ+/− mice. This mouse model also suggests that PIPKIγ may determine the level of gap junction contribution to cochlear development. PMID:22891314

  10. Versatile online-offline engine for automated acquisition of high-resolution tandem mass spectra.

    PubMed

    Wenger, Craig D; Boyne, Michael T; Ferguson, Jonathan T; Robinson, Dana E; Kelleher, Neil L

    2008-11-01

    For automated production of tandem mass spectrometric data for proteins and peptides >3 kDa at >50 000 resolution, a dual online-offline approach is presented here that improves upon standard liquid chromatography-tandem mass spectrometry (LC-MS/MS) strategies. An integrated hardware and software infrastructure analyzes online LC-MS data and intelligently determines which targets to interrogate offline using a posteriori knowledge such as prior observation, identification, and degree of characterization. This platform represents a way to implement accurate mass inclusion and exclusion lists in the context of a proteome project, automating collection of high-resolution MS/MS data that cannot currently be acquired on a chromatographic time scale at equivalent spectral quality. For intact proteins from an acid extract of human nuclei fractionated by reversed-phase liquid chromatography (RPLC), the automated offline system generated 57 successful identifications of protein forms arising from 30 distinct genes, a substantial improvement over online LC-MS/MS using the same 12 T LTQ FT Ultra instrument. Analysis of human nuclei subjected to a shotgun Lys-C digest using the same RPLC/automated offline sampling identified 147 unique peptides containing 29 co- and post-translational modifications. Expectation values ranged from 10 (-5) to 10 (-99), allowing routine multiplexed identifications. PMID:18841935

  11. Acquisition of a High Resolution Field Emission Scanning Electron Microscope for the Analysis of Returned Samples

    NASA Technical Reports Server (NTRS)

    Nittler, Larry R.

    2003-01-01

    This grant furnished funds to purchase a state-of-the-art scanning electron microscope (SEM) to support our analytical facilities for extraterrestrial samples. After evaluating several instruments, we purchased a JEOL 6500F thermal field emission SEM with the following analytical accessories: EDAX energy-dispersive x-ray analysis system with fully automated control of instrument and sample stage; EDAX LEXS wavelength-dispersive x-ray spectrometer for high sensitivity light-element analysis; EDAX/TSL electron backscatter diffraction (EBSD) system with software for phase identification and crystal orientation mapping; Robinson backscatter electron detector; and an in situ micro-manipulator (Kleindiek). The total price was $550,000 (with $150,000 of the purchase supported by Carnegie institution matching funds). The microscope was delivered in October 2002, and most of the analytical accessories were installed by January 2003. With the exception of the wavelength spectrometer (which has been undergoing design changes) everything is working well and the SEM is in routine use in our laboratory.

  12. Investigating the influence of chromatic aberration and optical illumination bandwidth on fundus imaging in rats.

    PubMed

    Li, Hao; Liu, Wenzhong; Zhang, Hao F

    2015-10-01

    Abstract. Rodent models are indispensable in studying various retinal diseases. Noninvasive, high-resolution retinal imaging of rodent models is highly desired for longitudinally investigating the pathogenesis and therapeutic strategies. However, due to severe aberrations, the retinal image quality in rodents can be much worse than that in humans. We numerically and experimentally investigated the influence of chromatic aberration and optical illumination bandwidth on retinal imaging. We confirmed that the rat retinal image quality decreased with increasing illumination bandwidth. We achieved the retinal image resolution of 10  μm using a 19 nm illumination bandwidth centered at 580 nm in a home-built fundus camera. Furthermore, we observed higher chromatic aberration in albino rat eyes than in pigmented rat eyes. This study provides a design guide for high-resolution fundus camera for rodents. Our method is also beneficial to dispersion compensation in multiwavelength retinal imaging applications. PMID:26502233

  13. Investigating the influence of chromatic aberration and optical illumination bandwidth on fundus imaging in rats

    NASA Astrophysics Data System (ADS)

    Li, Hao; Liu, Wenzhong; Zhang, Hao F.

    2015-10-01

    Rodent models are indispensable in studying various retinal diseases. Noninvasive, high-resolution retinal imaging of rodent models is highly desired for longitudinally investigating the pathogenesis and therapeutic strategies. However, due to severe aberrations, the retinal image quality in rodents can be much worse than that in humans. We numerically and experimentally investigated the influence of chromatic aberration and optical illumination bandwidth on retinal imaging. We confirmed that the rat retinal image quality decreased with increasing illumination bandwidth. We achieved the retinal image resolution of 10 μm using a 19 nm illumination bandwidth centered at 580 nm in a home-built fundus camera. Furthermore, we observed higher chromatic aberration in albino rat eyes than in pigmented rat eyes. This study provides a design guide for high-resolution fundus camera for rodents. Our method is also beneficial to dispersion compensation in multiwavelength retinal imaging applications.

  14. Cigarette acquisition and proof of age among US high school students who smoke

    PubMed Central

    Jones, S; Sharp, D; Husten, C; Crossett, L

    2002-01-01

    Objective: To determine how US high school students who are under 18 years of age and who smoke obtain their cigarettes and whether they are asked for proof of age. Design and setting: Data from the Centers for Disease Control and Prevention's 1995, 1997, and 1999 national Youth Risk Behavior Surveys which employed national probability samples of students in grades 9–12 (ages 14–18 years). Main outcome measures: Associations of usual source of cigarettes and request for proof of age with variables such as sex, race/ethnicity, grade, and frequency of smoking. Results: In 1999, among current smokers under age 18 years, 23.5% (95% confidence interval (CI), -4.5% to +4.5%) usually purchased their cigarettes in a store; among these students, 69.6% (95% CI -5.7% to +5.7%) were not asked to show proof of age. As days of past month smoking increased, reliance on buying cigarettes in a store (p < 0.001) and giving someone else money to buy cigarettes (p < 0.001) increased, and usually borrowing cigarettes decreased (p < 0.001). From 1995 to 1999, relying on store purchases significantly decreased (from 38.7% (95% CI -4.6% to + 4.6%) to 23.5% (95% CI -4.5% to +4.5%)); usually giving someone else money to buy cigarettes significantly increased (from 15.8% (95% CI -3.6% to +3.6%) to 29.9% (95% CI -4.5% to + 4.5%)). Conclusions: Stricter enforcement of tobacco access laws is needed to support other community and school efforts to reduce tobacco use among youth. Furthermore, effective interventions to reduce non-commercial sources of tobacco, including social, need to be developed and implemented. PMID:11891364

  15. Acquisition of a High-resolution Inductively Coupled Plasma Mass Spectrometer for Cosmochemical and Geochemical Research

    NASA Technical Reports Server (NTRS)

    Lauretta, D. S.

    2004-01-01

    The primary goal of our research in this program is to develop new techniques for the analysis of volatile trace elements in very small samples using inductively coupled plasma mass spectrometry (ICP-MS) in preparation for samples returned by the Stardust mission. The instrument that will serve as the basis of our experiments is the ELEMENT2 high-resolution ICP-MS. We have spent the past year designing the laboratory to house this instrument as well as space to store and prepare samples returned by the Stardust mission. Unfortunately, the location that we had initially selected for the instrument turned out to be insufficient for our needs. This was determined almost eight months into the first year of our funding cycle, after extensive work including the production of engineering drawings. However, during this time the Lunar and Planetary Laboratory was selected to lead Phoenix, the first Mars Scout mission. As a result of this award LPL purchased a new, 50,000 square foot building. We have acquired 1400 square feet of laboratory space in this new facility. Four-hundred square feet will be used for a class-100 clean room. This area is designated for storage and preparation of extraterrestrial materials. The additional 1000 square feet will house the ELEMENT2 ICP-MS and peripheral devices. This is an enormous amount of space for this instrument, but it provides plenty of room for expansion in the future. The ICP-MS and the clean room facilities have been purchased. The instrument has been delivered. The startup time for this instrument is relatively short and we expect to be collecting our first data by mid-summer.

  16. Evaluation of segmented 3D acquisition schemes for whole-brain high-resolution arterial spin labeling at 3 T.

    PubMed

    Vidorreta, Marta; Balteau, Evelyne; Wang, Ze; De Vita, Enrico; Pastor, María A; Thomas, David L; Detre, John A; Fernández-Seara, María A

    2014-11-01

    Recent technical developments have significantly increased the signal-to-noise ratio (SNR) of arterial spin labeled (ASL) perfusion MRI. Despite this, typical ASL acquisitions still employ large voxel sizes. The purpose of this work was to implement and evaluate two ASL sequences optimized for whole-brain high-resolution perfusion imaging, combining pseudo-continuous ASL (pCASL), background suppression (BS) and 3D segmented readouts, with different in-plane k-space trajectories. Identical labeling and BS pulses were implemented for both sequences. Two segmented 3D readout schemes with different in-plane trajectories were compared: Cartesian (3D GRASE) and spiral (3D RARE Stack-Of-Spirals). High-resolution perfusion images (2 × 2 × 4 mm(3) ) were acquired in 15 young healthy volunteers with the two ASL sequences at 3 T. The quality of the perfusion maps was evaluated in terms of SNR and gray-to-white matter contrast. Point-spread-function simulations were carried out to assess the impact of readout differences on the effective resolution. The combination of pCASL, in-plane segmented 3D readouts and BS provided high-SNR high-resolution ASL perfusion images of the whole brain. Although both sequences produced excellent image quality, the 3D RARE Stack-Of-Spirals readout yielded higher temporal and spatial SNR than 3D GRASE (spatial SNR = 8.5 ± 2.8 and 3.7 ± 1.4; temporal SNR = 27.4 ± 12.5 and 15.6 ± 7.6, respectively) and decreased through-plane blurring due to its inherent oversampling of the central k-space region, its reduced effective TE and shorter total readout time, at the expense of a slight increase in the effective in-plane voxel size. PMID:25263944

  17. Optical delay control of large-spectral-bandwidth laser pulses

    SciTech Connect

    Ignesti, E.; Tognetti, M. V.; Buffa, R.; Cavalieri, S.; Fini, L.; Sali, E.; Eramo, R.

    2009-07-15

    In this Rapid Communication we report an experimental observation of temporal delay control of large-spectral-bandwidth multimode laser pulses by means of electromagnetically induced transparency. We achieved optically controllable retardation of laser pulses with an input spectral bandwidth of 3.3 GHz with limited temporal distortion and excellent values of the delay-bandwidth product. The experimental results compare favorably with a theoretical analysis.

  18. Real-time wavelength and bandwidth-independent optical integrator based on modal dispersion.

    PubMed

    Tan, Zhongwei; Wang, Chao; Diebold, Eric D; Hon, Nick K; Jalali, Bahram

    2012-06-18

    High-throughput real-time optical integrators are of great importance for applications that require ultrafast optical information processing, such as real-time phase reconstruction of ultrashort optical pulses. In many of these applications, integration of wide optical bandwidth signals is required. Unfortunately, conventional all-optical integrators based on passive devices are usually sensitive to the wavelength and bandwidth of the optical carrier. Here, we propose and demonstrate a passive all-optical intensity integrator whose operation is independent of the optical signal wavelength and bandwidth. The integrator is implemented based on modal dispersion in a multimode waveguide. By controlling the launch conditions of the input beam, the device produces a rectangular temporal impulse response. Consequently, a temporal intensity integration of an arbitrary optical waveform input is performed within the rectangular time window. The key advantage of this device is that the integration operation can be performed independent of the input signal wavelength and optical carrier bandwidth. This is preferred in many applications where optical signals of different wavelengths are involved. Moreover, thanks to the use of a relatively short length of multimode waveguide, lower system latency is achieved compared to the systems using long dispersive fibers. To illustrate the versatility of the optical integrator, we demonstrate temporal intensity integration of optical waveforms with different wavelengths and optical carrier bandwidths. Finally, we use this device to perform high-throughput, single-shot, real-time optical phase reconstruction of phase-modulated signals at telecommunications bit rates.

  19. Data acquisition systems for the high energy and Nuclotron internal target polarimeters with network access to polarization calculation results and raw data

    NASA Astrophysics Data System (ADS)

    Isupov, A. Yu.

    2005-01-01

    Online data acquisition (DAQ) system for the Nuclotron Internal Target Polarimeter (ITP) at the LHE, JINR is explained in respects of design and implementation, based on the distributed data acquisition and processing system qdpb. Software modules specific for this implementation (dependent of ITP data contents and hardware layout) are discussed briefly in comparison with them for the High Energy Polarimeter (HEP) at the LHE, JINR. User access methods to both raw data and results of polarization calculations of the ITP and HEP are described.

  20. Feasibility studies of optical processing of image bandwidth compression schemes

    NASA Astrophysics Data System (ADS)

    Hunt, B. R.; Strickland, R. N.; Schowengerdt, R. A.

    1983-05-01

    This research focuses on these three areas: (1) formulation of alternative architectural concepts for image bandwidth compression, i.e., the formulation of components and schematic diagrams which differ from conventional digital bandwidth compression schemes by being implemented by various optical computation methods; (2) simulation of optical processing concepts for image bandwidth compression, so as to gain insight into typical performance parameters and elements of system performance sensitivity; and (3) maturation of optical processing for image bandwidth compression until the overall state of optical methods in image compression becomes equal to that of digital image compression.

  1. Frequency Bandwidth Optimization of Left-Handed Metamaterial

    NASA Technical Reports Server (NTRS)

    Chevalier, Christine T.; Wilson, Jeffrey D.

    2004-01-01

    Recently, left-handed metamaterials (LHM s) have been demonstrated with an effective negative index of refraction and with antiparallel group and phase velocities for microwave radiation over a narrow frequency bandwidth. In order to take advantage of these characteristics for practical applications, it will be beneficial to develop LHM s with increased frequency bandwidth response and lower losses. In this paper a commercial three-dimensional electromagnetic simulation code is used to explore the effects of geometry parameter variations on the frequency bandwidth of a LHM at microwave frequencies. Utilizing an optimizing routine in the code, a geometry was generated with a bandwidth more than twice as large as the original geometry.

  2. PIC Simulation of Laser Plasma Interactions with Temporal Bandwidths

    NASA Astrophysics Data System (ADS)

    Tsung, Frank; Weaver, J.; Lehmberg, R.

    2015-11-01

    We are performing particle-in-cell simulations using the code OSIRIS to study the effects of laser plasma interactions in the presence of temperal bandwidths under conditions relevant to current and future shock ignition experiments on the NIKE laser. Our simulations show that, for sufficiently large bandwidth, the saturation level, and the distribution of hot electrons, can be effected by the addition of temporal bandwidths (which can be accomplished in experiments using smoothing techniques such as SSD or ISI). We will show that temporal bandwidth along play an important role in the control of LPI's in these lasers and discuss future directions. This work is conducted under the auspices of NRL.

  3. The Power of Imageability: How the Acquisition of Inflected Forms Is Facilitated in Highly Imageable Verbs and Nouns in Czech Children

    ERIC Educational Resources Information Center

    Smolík, Filip; Kríž, Adam

    2015-01-01

    Imageability is the ability of words to elicit mental sensory images of their referents. Recent research has suggested that imageability facilitates the processing and acquisition of inflected word forms. The present study examined whether inflected word forms are acquired earlier in highly imageable words in Czech children. Parents of 317…

  4. The Effect of Data Acquisition-Probeware and Digital Video Analysis on Accurate Graphical Representation of Kinetics in a High School Physics Class

    ERIC Educational Resources Information Center

    Struck, William; Yerrick, Randy

    2010-01-01

    The effects of two types of two well-established microcomputer-based teaching methods were examined for their effect on teaching high school students kinetics. The use of data acquisition probeware and digital video analysis were studied for their impact on students' conceptions and ability to interpret graphical relationships to real world…

  5. Control of a pointing, acquisition, and tracking subsystem for intersatellite laser links ISL2

    NASA Astrophysics Data System (ADS)

    Kern, R.; Kuel, U.; Hettlage, E.

    1987-01-01

    It is shown that the dynamical requirements determined for a CO2 lasercom system can be met with the fine pointing assembly (FPA) and the coarse pointing assembly (CPA) described here. The implemented control loops and the corresponding control logic provide the PAT subsystem with a high bandwidth and a short transition time from the acquisition to the tracking mode. It is demonstrated that the maximum angular rate of the LOS in connection with the maximum slew rate of the CPA and the magnification factor of the telescope determine the area around the singular point which the FPA must be able to cover.

  6. Power and Efficiency Optimized in Traveling-Wave Tubes Over a Broad Frequency Bandwidth

    NASA Technical Reports Server (NTRS)

    Wilson, Jeffrey D.

    2001-01-01

    A traveling-wave tube (TWT) is an electron beam device that is used to amplify electromagnetic communication waves at radio and microwave frequencies. TWT's are critical components in deep space probes, communication satellites, and high-power radar systems. Power conversion efficiency is of paramount importance for TWT's employed in deep space probes and communication satellites. A previous effort was very successful in increasing efficiency and power at a single frequency (ref. 1). Such an algorithm is sufficient for narrow bandwidth designs, but for optimal designs in applications that require high radiofrequency power over a wide bandwidth, such as high-density communications or high-resolution radar, the variation of the circuit response with respect to frequency must be considered. This work at the NASA Glenn Research Center is the first to develop techniques for optimizing TWT efficiency and output power over a broad frequency bandwidth (ref. 2). The techniques are based on simulated annealing, which has the advantage over conventional optimization techniques in that it enables the best possible solution to be obtained (ref. 3). Two new broadband simulated annealing algorithms were developed that optimize (1) minimum saturated power efficiency over a frequency bandwidth and (2) simultaneous bandwidth and minimum power efficiency over the frequency band with constant input power. The algorithms were incorporated into the NASA coupled-cavity TWT computer model (ref. 4) and used to design optimal phase velocity tapers using the 59- to 64-GHz Hughes 961HA coupled-cavity TWT as a baseline model. In comparison to the baseline design, the computational results of the first broad-band design algorithm show an improvement of 73.9 percent in minimum saturated efficiency (see the top graph). The second broadband design algorithm (see the bottom graph) improves minimum radiofrequency efficiency with constant input power drive by a factor of 2.7 at the high band edge (64

  7. Dynamic high-speed acquisition system design of transmission error with USB based on LabVIEW and FPGA

    NASA Astrophysics Data System (ADS)

    Zheng, Yong; Chen, Yan

    2013-10-01

    To realize the design of dynamic acquisition system for real-time detection of transmission chain error is very important to improve the machining accuracy of machine tool. In this paper, the USB controller and FPGA is used for hardware platform design, combined with LabVIEW to design user applications, NI-VISA is taken for develop USB drivers, and ultimately achieve the dynamic acquisition system design of transmission error

  8. Evaluation of ‘OpenCL for FPGA’ for Data Acquisition and Acceleration in High Energy Physics

    NASA Astrophysics Data System (ADS)

    Sridharan, Srikanth

    2015-12-01

    The increase in the data acquisition and processing needs of High Energy Physics experiments has made it more essential to use FPGAs to meet those needs. However harnessing the capabilities of the FPGAs has been hard for anyone but expert FPGA developers. The arrival of OpenCL with the two major FPGA vendors supporting it, offers an easy software-based approach to taking advantage of FPGAs in applications such as High Energy Physics. OpenCL is a language for using heterogeneous architectures in order to accelerate applications. However, FPGAs are capable of far more than acceleration, hence it is interesting to explore if OpenCL can be used to take advantage of FPGAs for more generic applications. To answer these questions, especially in the context of High Energy Physics, two applications, a DAQ module and an acceleration workload, were tested for implementation with OpenCL on FPGAs2. The challenges on using OpenCL for a DAQ application and their solutions, together with the performance of the OpenCL based acceleration are discussed. Many of the design elements needed to realize a DAQ system in OpenCL already exists, mostly as FPGA vendor extensions, but a small number of elements were found to be missing. For acceleration of OpenCL applications, using FPGAs has become as easy as using GPUs. OpenCL has the potential for a massive gain in productivity and ease of use enabling non FPGA experts to design, debug and maintain the code. Also, FPGA power consumption is much lower than other implementations. This paper describes one of the first attempts to explore the use of OpenCL for applications outside the acceleration workloads.

  9. Effects of health facilitator performance and attendance at training sessions on the acquisition of tobacco refusal skills among multi-ethnic, high-risk adolescents.

    PubMed

    Elder, J P; Woodruff, S I; Sallis, J F; de Moor, C; Edwards, C; Wildey, M B

    1994-06-01

    The study examined the effectiveness of a psycho-social tobacco use prevention intervention with a refusal skills training component on the refusal skills of high-risk adolescents, and investigated skill acquisition as related to subject demographics, performance of health facilitators and attendance at skills training sessions. Tobacco refusal skills were assessed for a group (n = 389) of high-risk, seventh-grade students participating as intervention and control subjects in Project SHOUT, a large tobacco use prevention program in the San Diego area. In addition, subject demographics, ratings of health facilitator performance and information about subjects' attendance at skills training sessions were collected. Subjects' responses to audiotaped peer offers of cigarettes and smokeless tobacco were coded for content and quality. Greater tobacco refusal skills among intervention subjects was hypothesized. Further health facilitator performance, attendance at training sessions and subject demographics were thought to be related to skill acquisition. High-risk intervention subjects gave significantly higher quality tobacco-refusal responses than did controls, although the differences between means were small. Results suggested that Hispanic adolescents were particularly receptive to the refusal skills training. The association between health facilitator performance and skill acquisition varied by subject ethnicity, as did the relationship between attendance at training sessions and skill acquisition. PMID:10150446

  10. Plasmonic photodetector with terahertz electrical bandwidth

    NASA Astrophysics Data System (ADS)

    Mousavi, Saba Siadat; Stöhr, Andreas; Berini, Pierre

    2014-04-01

    We propose and investigate a surface plasmon photodetector concept, based on the enhancement of electrical near-field in low-defect, low-doped In0.53Ga0.47As detection volumes located in the gaps of an array of metal nanodipole antennas. We report enhancement in responsivity in the presence of nanodipoles and predict a maximum responsivity of ˜100 mA/W at wavelengths near 1550 nm. The 3 dB electrical bandwidth of the device is estimated based on its RC rise time and the hole transit time through the detection volume for the cases of conventional and ballistic transport in InGaAs and is found to range from ˜0.7 to 4 THz. Also, trends are observed relating the responsivity to the gap dimensions, revealing a trade-off between the field-enhancement in the gap and its volume, and leading to an optimum gap length producing the maximum responsivity.

  11. Acquisition of high-level chromosomal instability is associated with integration of human papillomavirus type 16 in cervical keratinocytes.

    PubMed

    Pett, Mark R; Alazawi, William O F; Roberts, Ian; Dowen, Sally; Smith, David I; Stanley, Margaret A; Coleman, Nicholas

    2004-02-15

    Whereas two key steps in cervical carcinogenesis are integration of high-risk human papillomavirus (HR-HPV) and acquisition of an unstable host genome, the temporal association between these events is poorly understood. Chromosomal instability is induced when HR-HPV E7 oncoprotein is overexpressed from heterologous promoters in vitro. However, it is not known whether such events occur at the "physiologically" elevated levels of E7 produced by deregulation of the homologous HR-HPV promoter after integration. Indeed, an alternative possibility is that integration in vivo is favored in an already unstable host genome. We have addressed these issues using the unique human papillomavirus (HPV) 16-containing cervical keratinocyte cell line W12, which was derived from a low-grade squamous intraepithelial lesion and thus acquired HPV16 by "natural" infection. Whereas W12 at low passage contains HPV16 episomes only, long-term culture results in the emergence of cells containing integrated HPV16 only. We show that integration of HPV16 in W12 is associated with 3' deletion of the E2 transcriptional repressor, resulting in deregulation of the homologous promoter of the integrant and an increase in E7 protein levels. We further demonstrate that high-level chromosomal instability develops in W12 only after integration and that the forms of instability observed correlate with the physical state of HPV16 DNA and the level of E7 protein. Whereas intermediate E7 levels are associated with numerical chromosomal abnormalities, maximal levels are associated with both numerical and structural aberrations. HR-HPV integration is likely to be a critical event in cervical carcinogenesis, preceding the development of chromosomal abnormalities that drive malignant progression.

  12. Wide-Bandwidth Capture of Wire-Scanner Signals

    SciTech Connect

    Gruchalla, Michael E.; Gilpatrick, John D.; Sedillo, James Daniel; Martinez, Derwin

    2012-05-16

    Integrated charge collected on the sense wires of wire-scanner systems utilized to determine beam profile is generally the parameter of interest. The LANSCE application requires capturing the charge information macropulse-by-macropulse with macropulse lengths as long as 700 {micro}s at a maximum macropulse rate of 120 Hz. Also, for the LANSCE application, it is required that the integration be performed in a manner that does not require integrator reset between macropulses. Due to the long macropulse which must be accommodated and the 8.33 ms minimum pulse period, a simple R-C integrator cannot be utilized since there is insufficient time between macropulses to allow the integrator to adequately recover. The application of wide analog bandwidth to provide accurate pulse-by-pulse capture of the wire signals with digital integration of the wire signals to determine captured charge at each macropulse in applications with comparatively long macropulses and high pulse repetition rates is presented.

  13. Transformation optics for antennas: why limit the bandwidth with metamaterials?

    PubMed

    Quevedo-Teruel, Oscar; Tang, Wenxuan; Mitchell-Thomas, Rhiannon C; Dyke, Amy; Dyke, Hazel; Zhang, Lianhong; Haq, Sajad; Hao, Yang

    2013-01-01

    In the last decade, a technique termed transformation optics has been developed for the design of novel electromagnetic devices. This method defines the exact modification of magnetic and dielectric constants required, so that the electromagnetic behaviour remains invariant after a transformation to a new coordinate system. Despite the apparently infinite possibilities that this mathematical tool introduces, one restriction has repeatedly recurred since its conception: limited frequency bands of operation. Here we circumvent this problem with the proposal of a full dielectric implementation of a transformed planar hyperbolic lens which retains the same focusing properties of an original curved lens. The redesigned lens demonstrates operation with high directivity and low side lobe levels for an ultra-wide band of frequencies, spanning over three octaves. The methodology proposed in this paper can be applied to revolutionise the design of many electromagnetic devices overcoming bandwidth limitations.

  14. Transformation optics for antennas: why limit the bandwidth with metamaterials?

    PubMed Central

    Quevedo-Teruel, Oscar; Tang, Wenxuan; Mitchell-Thomas, Rhiannon C.; Dyke, Amy; Dyke, Hazel; Zhang, Lianhong; Haq, Sajad; Hao, Yang

    2013-01-01

    In the last decade, a technique termed transformation optics has been developed for the design of novel electromagnetic devices. This method defines the exact modification of magnetic and dielectric constants required, so that the electromagnetic behaviour remains invariant after a transformation to a new coordinate system. Despite the apparently infinite possibilities that this mathematical tool introduces, one restriction has repeatedly recurred since its conception: limited frequency bands of operation. Here we circumvent this problem with the proposal of a full dielectric implementation of a transformed planar hyperbolic lens which retains the same focusing properties of an original curved lens. The redesigned lens demonstrates operation with high directivity and low side lobe levels for an ultra-wide band of frequencies, spanning over three octaves. The methodology proposed in this paper can be applied to revolutionise the design of many electromagnetic devices overcoming bandwidth limitations. PMID:23712699

  15. Transformation optics for antennas: why limit the bandwidth with metamaterials?

    NASA Astrophysics Data System (ADS)

    Quevedo-Teruel, Oscar; Tang, Wenxuan; Mitchell-Thomas, Rhiannon C.; Dyke, Amy; Dyke, Hazel; Zhang, Lianhong; Haq, Sajad; Hao, Yang

    2013-05-01

    In the last decade, a technique termed transformation optics has been developed for the design of novel electromagnetic devices. This method defines the exact modification of magnetic and dielectric constants required, so that the electromagnetic behaviour remains invariant after a transformation to a new coordinate system. Despite the apparently infinite possibilities that this mathematical tool introduces, one restriction has repeatedly recurred since its conception: limited frequency bands of operation. Here we circumvent this problem with the proposal of a full dielectric implementation of a transformed planar hyperbolic lens which retains the same focusing properties of an original curved lens. The redesigned lens demonstrates operation with high directivity and low side lobe levels for an ultra-wide band of frequencies, spanning over three octaves. The methodology proposed in this paper can be applied to revolutionise the design of many electromagnetic devices overcoming bandwidth limitations.

  16. Memory bandwidth-scalable motion estimation for mobile video coding

    NASA Astrophysics Data System (ADS)

    Hsieh, Jui-Hung; Tai, Wei-Cheng; Chang, Tian-Sheuan

    2011-12-01

    The heavy memory access of motion estimation (ME) execution consumes significant power and could limit ME execution when the available memory bandwidth (BW) is reduced because of access congestion or changes in the dynamics of the power environment of modern mobile devices. In order to adapt to the changing BW while maintaining the rate-distortion (R-D) performance, this article proposes a novel data BW-scalable algorithm for ME with mobile multimedia chips. The available BW is modeled in a R-D sense and allocated to fit the dynamic contents. The simulation result shows 70% BW savings while keeping equivalent R-D performance compared with H.264 reference software for low-motion CIF-sized video. For high-motion sequences, the result shows our algorithm can better use the available BW to save an average bit rate of up to 13% with up to 0.1-dB PSNR increase for similar BW usage.

  17. Inhibitors of TonB function identified by a high-throughput screen for inhibitors of iron acquisition in uropathogenic Escherichia coli CFT073.

    PubMed

    Yep, Alejandra; McQuade, Thomas; Kirchhoff, Paul; Larsen, Martha; Mobley, Harry L T

    2014-02-25

    The urinary tract is one of the most common sites of infection in humans, and uropathogenic Escherichia coli (UPEC) is the main causative agent of urinary tract infections. Bacteria colonizing the urinary tract face extremely low iron availability. To counteract this, UPEC expresses a wide variety of iron acquisition systems. To exploit iron acquisition in UPEC as a global target for small-molecule inhibition, we developed and carried out a whole-cell growth-based high throughput screen of 149,243 compounds. Our primary assay was carried out under iron-limiting conditions. Hits in the primary screen were assayed using two counterscreens that ruled out iron chelators and compounds that inhibit growth by means other than inhibition of iron acquisition. We determined dose-response curves under two different iron conditions and purchased fresh compounds for selected hits. After retesting dose-response relationships, we identified 16 compounds that arrest growth of UPEC only under iron-limiting conditions. All compounds are bacteriostatic and do not inhibit proton motive force. A loss-of-target strategy was employed to identify the cellular target of these inhibitors. Two compounds lost inhibitory activity against a strain lacking TonB and were shown to inhibit irreversible adsorption of a TonB-dependent bacteriophage. Our results validate iron acquisition as a target for antibacterial strategies against UPEC and identify TonB as one of the cellular targets. IMPORTANCE Half of women will suffer at least one episode of urinary tract infection (UTI) during their lifetime. The current treatment for UTI involves antibiotic therapy. Resistance to currently used antibiotics has steadily increased over the last decade, generating a pressing need for the development of new therapeutic agents. Since iron is essential for colonization and scarce in the urinary tract, targeting iron acquisition would seem to be an attractive strategy. However, the multiplicity and redundancy of

  18. Improving the chaos bandwidth of a semiconductor laser with phase-conjugate feedback

    NASA Astrophysics Data System (ADS)

    Mercier, Émeric; Wolfersberger, Delphine; Sciamanna, Marc

    2016-04-01

    Common applications using optical chaos in a semiconductor laser include, among others, random number generation and chaos-encrypted communications. They rely on chaos of high dimension with a large bandwidth and a high entropy growth rate to achieve good results. Optical chaos from a semiconductor laser with conventional optical feedback (COF) is typically used as the primary source of chaos. Additional enhancing techniques are used to enlarge the chaos bandwidth. In this contribution, we show experimentally how using phase-conjugate feedback (PCF) can naturally produce a chaos of higher bandwidth than COF. PCF is an alternative to COF which consists of feeding the conjugate of the optical output back into the laser cavity, with a time-delay. Thanks to an oscilloscope with a fast sampling rate, and a large bandwidth, we were able to measure and observe the time-resolved frequency dynamics with a good precision. In the regime of low-frequency fluctuations (LFF), where dropouts of optical power occur randomly, we were able to compare the difference in dynamics before and after a dropout, for PCF and COF. In the range of attainable reflectivities, we measured a bandwidth increase of up to 27 % with PCF when compared to COF. Interestingly, we found that high-frequency dynamics are enabled before dropouts in PCF, where it was theoretically shown that the system jumps between destabilized self-pulsing states at harmonics of the external-cavity frequency, the so-called external-cavity modes (ECMs). This observation tends to confirm that ECMs in PCF are indeed fundamentally different than ECMs in COF, where they are simple steady-states. Finally, we believe that the enhancing techniques used with COF could also be used with PCF to obtain even wider chaotic bandwidths. These results could lead to studies about the dimension and the entropy growth rate of chaos from a laser diode with PCF.

  19. Methicillin-Resistant Staphylococcus aureus: Site of Acquisition and Strain Variation in High-Risk Nursing Home Residents with Indwelling Devices

    PubMed Central

    Gibson, Kristen E.; McNamara, Sara E.; Cassone, Marco; Perri, Mary Beth; Zervos, Marcus; Mody, Lona

    2015-01-01

    OBJECTIVE Characterize the clinical and molecular epidemiology of new methicillin-resistant Staphylococcus aureus (MRSA) acquisitions at nasal and extranasal sites among high-risk nursing home (NH) residents. DESIGN Multicenter prospective observational study. SETTING Six NHs in southeast Michigan. PARTICIPANTS A total of 120 NH residents with an indwelling device (feeding tube and/or urinary catheter). METHODS Active surveillance cultures from the nares, oropharynx, groin, perianal area, wounds (if present), and device insertion site(s) were collected upon enrollment, at day 14, and monthly thereafter. Pulsed-field gel electrophoresis and polymerase chain reaction for SCCmec, agr, and Panton-Valentine leukocidin were performed. RESULTS Of 120 participants observed for 16,290 device-days, 50 acquired MRSA (78% transiently, 22% persistently). New MRSA acquisitions were common in extranasal sites, particularly at device insertion, groin, and perianal areas (27%, 23%, and 17.6% of all acquisitions, respectively). Screening extranasal sites greatly increases the detection of MRSA colonization (100% of persistent carriers and 97.4% of transient carriers detected with nares, groin, perianal, and device site sampling vs 54.5% and 25.6%, respectively, for nares samples alone). Colonization at suprapubic urinary catheter sites generally persisted. Healthcare-associated MRSA (USA100 and USA100 variants) were the dominant strains (79.3% of all new acquisition isolates). Strain diversity was more common in transient carriers, including acquisition of USA500 and USA300 strains. CONCLUSION Indwelling device insertion sites as well as the groin and perianal area are important sites of new MRSA acquisitions in NH residents and play a role in the persistency of MRSA carriage. Clonal types differ among persistent and transient colonizers. PMID:25419767

  20. XSTREAM: A Highly Efficient High Speed Real-time Satellite Data Acquisition and Processing System using Heterogeneous Computing

    NASA Astrophysics Data System (ADS)

    Pramod Kumar, K.; Mahendra, P.; Ramakrishna rReddy, V.; Tirupathi, T.; Akilan, A.; Usha Devi, R.; Anuradha, R.; Ravi, N.; Solanki, S. S.; Achary, K. K.; Satish, A. L.; Anshu, C.

    2014-11-01

    In the last decade, the remote sensing community has observed a significant growth in number of satellites, sensors and their resolutions, thereby increasing the volume of data to be processed each day. Satellite data processing is a complex and time consuming activity. It consists of various tasks, such as decode, decrypt, decompress, radiometric normalization, stagger corrections, ephemeris data processing for geometric corrections etc., and finally writing of the product in the form of an image file. Each task in the processing chain is sequential in nature and has different computing needs. Conventionally the processes are cascaded in a well organized workflow to produce the data products, which are executed on general purpose high-end servers / workstations in an offline mode. Hence, these systems are considered to be ineffective for real-time applications that require quick response and just-intime decision making such as disaster management, home land security and so on. This paper discusses anovel approach to processthe data online (as the data is being acquired) using a heterogeneous computing platform namely XSTREAM which has COTS hardware of CPUs, GPUs and FPGA. This paper focuses on the process architecture, re-engineering aspects and mapping of tasks to the right computing devicewithin the XSTREAM system, which makes it an ideal cost-effective platform for acquiring, processing satellite payload data in real-time and displaying the products in original resolution for quick response. The system has been tested for IRS CARTOSAT and RESOURCESAT series of satellites which have maximum data downlink speed of 210 Mbps.

  1. 47 CFR 101.809 - Bandwidth and emission limitations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Bandwidth and emission limitations. 101.809 Section 101.809 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Local Television Transmission Service § 101.809 Bandwidth and...

  2. 47 CFR 101.809 - Bandwidth and emission limitations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Bandwidth and emission limitations. 101.809 Section 101.809 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Local Television Transmission Service § 101.809 Bandwidth and...

  3. 47 CFR 101.809 - Bandwidth and emission limitations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Bandwidth and emission limitations. 101.809 Section 101.809 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Local Television Transmission Service § 101.809 Bandwidth and...

  4. 47 CFR 101.809 - Bandwidth and emission limitations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Bandwidth and emission limitations. 101.809 Section 101.809 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Local Television Transmission Service § 101.809 Bandwidth and...

  5. 47 CFR 101.809 - Bandwidth and emission limitations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Bandwidth and emission limitations. 101.809 Section 101.809 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Local Television Transmission Service § 101.809 Bandwidth and...

  6. Optimal Bandwidth Selection in Observed-Score Kernel Equating

    ERIC Educational Resources Information Center

    Häggström, Jenny; Wiberg, Marie

    2014-01-01

    The selection of bandwidth in kernel equating is important because it has a direct impact on the equated test scores. The aim of this article is to examine the use of double smoothing when selecting bandwidths in kernel equating and to compare double smoothing with the commonly used penalty method. This comparison was made using both an equivalent…

  7. 47 CFR 2.1049 - Measurements required: Occupied bandwidth.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... established at the frequency of maximum response of the audio modulating circuit. (2) Single sideband....1049 Section 2.1049 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL FREQUENCY ALLOCATIONS... Certification § 2.1049 Measurements required: Occupied bandwidth. The occupied bandwidth, that is the...

  8. Acquisition strategies

    SciTech Connect

    Zimmer, M.J.; Lynch, P.W. )

    1993-11-01

    Acquiring projects takes careful planning, research and consideration. Picking the right opportunities and avoiding the pitfalls will lead to a more valuable portfolio. This article describes the steps to take in evaluating an acquisition and what items need to be considered in an evaluation.

  9. Spectral structure of laser light scattering revisited: bandwidths of nonresonant scattering lidars.

    PubMed

    She, C Y

    2001-09-20

    It is well known that scattering lidars, i.e., Mie, aerosol-wind, Rayleigh, high-spectral-resolution, molecular-wind, rotational Raman, and vibrational Raman lidars, are workhorses for probing atmospheric properties, including the backscatter ratio, aerosol extinction coefficient, temperature, pressure, density, and winds. The spectral structure of molecular scattering (strength and bandwidth) and its constituent spectra associated with Rayleigh and vibrational Raman scattering are reviewed. Revisiting the correct name by distinguishing Cabannes scattering from Rayleigh scattering, and sharpening the definition of each scattering component in the Rayleigh scattering spectrum, the review allows a systematic, logical, and useful comparison in strength and bandwidth between each scattering component and in receiver bandwidths (for both nighttime and daytime operation) between the various scattering lidars for atmospheric sensing. PMID:18360530

  10. Global path and bandwidth scheduling in inter-data-center IP/optical transport network

    NASA Astrophysics Data System (ADS)

    Zhao, Yang; Wang, Lei; Chen, Xue; Yang, Futao; Shi, Sheping; Wang, Huitao

    2016-07-01

    We propose a flow-oriented global path and bandwidth scheduling scheme for inter-data-center IP/optical network. To improve the throughput of network and reduce the mutual impact between flows, we allow each flow to be carried by a multi-path optical channel data unit (ODU) channel. In addition bandwidth is allocated to flows fairly according to weight. Simulation results reveal that compared to high-priority-first mechanism, the method proposed improves average bandwidth allocation ratio by about 15% and allocation fairness between flows by 30%. Furthermore, compared to pure IP network, router ports are significantly saved and network cost can be reduced by up to 40% with scheme proposed in unified controlled IP/optical network.

  11. Frequency up-converted wide bandwidth piezoelectric energy harvester using mechanical impact

    NASA Astrophysics Data System (ADS)

    Halim, Miah A.; Khym, S.; Park, J. Y.

    2013-07-01

    This paper presents an impact based frequency up-converted wide bandwidth piezoelectric energy harvester in which two high frequency piezoelectric generating beams are struck at the same time by a low frequency driving beam having horizontally extended tip mass. Change of driving beam's effective stiffness during coupled vibration after impact allows the device to broaden the -3dB bandwidth to approximately 170% and to acquire more than 61% of the maximum power generation in the vicinity (from 7 to 10.5 Hz) of the -3 dB bandwidth region as well. The efficiency of electrical power transfer is increased to approximately 85%. Each generating beam produces 377 μW peak power at 14.5 Hz under 0.6 g acceleration with corresponding power density 58.8 μW cm-3.

  12. Multiplexing OAM states in an optical fiber: Increase bandwidth of quantum communication and QKD applications

    NASA Astrophysics Data System (ADS)

    Gupta, Manish Kumar; Dowling, Jonathan P.

    2015-05-01

    We propose a noble method for multiplexing OAM states to increase bandwidth of communication in a birefringent single-mode optical fiber for quantum communication and QKD applications by minimizing the decoherence. We analytically derive and show that the rate of decoherence for OAM state in a birefringent optical fiber is proportional to l2. We also show numerically that decoherence can be minimized with CPMG pulse sequence to preserve the state with > 90 % fidelity for smaller values of l to allow for high-bandwidth communication. Louisiana State University, Baton Rouge, Louisiana 70803, USA.

  13. The effect of bandwidth on telerobot system performance

    NASA Technical Reports Server (NTRS)

    Uebel, Mark; Ali, Michael S.; Minis, Ioannis

    1991-01-01

    The purpose of the experiment was to determine the effect that various slave-joint bandwidths have on telerobot system performance. The telerobot system consisted of a slave arm controlled by a master. The slave incorporated an impedance loop to provide local compliance in addition to the compliance provided by the operator via force feedback. Three joint bandwidths, 0.5, 1.0, and 2.0 Hz, were used. The performance measures were the task completion time and the sums of the squared forces and moments exerted on the environment. The task consisted of peg-in-hole insertion and removal. The results of the experiment indicate a significant performance decrease at 0.5-Hz bandwidth relative to the 1- and 2-Hz bandwidths. There was no significant change in performance between the 1- and 2-Hz bandwidths.

  14. The effect of stimulus bandwidth on binaural loudness summation.

    PubMed

    Shao, Zhiyue; Mo, Fangshuo; Mao, Dongxing

    2015-09-01

    Binaural loudness summation is an important property of the human auditory system. This paper presents an experimental investigation of how binaural loudness summation varies with stimulus bandwidth. Loudness matches were obtained between dichotic stimuli, with interaural level differences (ILDs) of 2-12 dB, and diotic stimuli. The stimuli were noise bands with seven center frequencies and four bandwidths. Results showed that the loudness of dichotic stimuli increased nonlinearly with ILD, the increase being slightly less with broader bandwidths. There was a bandwidth-dependent difference between the listening tests results and the predictions of Moore and Glasberg's [(2007) J. Acoust. Soc. Am. 121, 1604-1612] loudness model. The size of the difference was, however, small. A characteristic function was derived describing how overall loudness depends on stimulus bandwidth and ILD. PMID:26428788

  15. Re-detection vs. new acquisition of high-risk human papillomavirus in mid-adult women.

    PubMed

    Fu, Tsung-Chieh Jane; Carter, Joseph J; Hughes, James P; Feng, Qinghua; Hawes, Stephen E; Schwartz, Stephen M; Xi, Long Fu; Lasof, Taylor; Stern, Joshua E; Galloway, Denise A; Koutsky, Laura A; Winer, Rachel L

    2016-11-15

    To understand high-risk (hr) human papillomavirus (HPV) epidemiology in mid-adulthood, we assessed whether associations between incident detection of hrHPV DNA and recent sexual behavior differed according to whether or not there was serologic evidence of prior infection. From 2011 to 2012, we enrolled 409 women aged 30-50 years into a 6-month longitudinal study. We collected health and sexual behavior histories, enrollment sera for HPV antibody testing, and monthly self-collected vaginal swabs for HPV DNA genotyping. Generalized estimating equations logistic regression identified risk factors for type-specific incident hrHPV DNA, stratified by type-specific hrHPV serostatus at enrollment. Population attributable risks of hrHPV due to prior and recent exposure were estimated. When type-specific hrHPV serology was negative, recent sexual risk behavior was positively associated with incident hrHPV DNA (odds ratio in women reporting ≥3 recent sexual risk behaviors [e.g., new or multiple partners] vs. no recent sexual activity = 9.8, 95% CI: 2.4-40.6). No associations with recent sexual behavior were observed with positive type-specific hrHPV serology. Thirty percent of incident hrHPV DNA detection was attributable to prior infection (with positive serology) and 40% was attributable to recent sexual risk behavior (with negative serology). The proportion of incident hrHPV DNA detection attributable to recent sexual risk behavior decreased with increasing age. Among women with serologic evidence of prior infection, re-detection of the same hrHPV type is likely due to reactivation or intermittent detection of persistent infection. Without serologic evidence of prior infection, new detection is likely due to new acquisition or to intermittent detection of persisting infection. PMID:27448488

  16. A direct-to-drive neural data acquisition system.

    PubMed

    Kinney, Justin P; Bernstein, Jacob G; Meyer, Andrew J; Barber, Jessica B; Bolivar, Marti; Newbold, Bryan; Scholvin, Jorg; Moore-Kochlacs, Caroline; Wentz, Christian T; Kopell, Nancy J; Boyden, Edward S

    2015-01-01

    Driven by the increasing channel count of neural probes, there is much effort being directed to creating increasingly scalable electrophysiology data acquisition (DAQ) systems. However, all such systems still rely on personal computers for data storage, and thus are limited by the bandwidth and cost of the computers, especially as the scale of recording increases. Here we present a novel architecture in which a digital processor receives data from an analog-to-digital converter, and writes that data directly to hard drives, without the need for a personal computer to serve as an intermediary in the DAQ process. This minimalist architecture may support exceptionally high data throughput, without incurring costs to support unnecessary hardware and overhead associated with personal computers, thus facilitating scaling of electrophysiological recording in the future.

  17. A direct-to-drive neural data acquisition system.

    PubMed

    Kinney, Justin P; Bernstein, Jacob G; Meyer, Andrew J; Barber, Jessica B; Bolivar, Marti; Newbold, Bryan; Scholvin, Jorg; Moore-Kochlacs, Caroline; Wentz, Christian T; Kopell, Nancy J; Boyden, Edward S

    2015-01-01

    Driven by the increasing channel count of neural probes, there is much effort being directed to creating increasingly scalable electrophysiology data acquisition (DAQ) systems. However, all such systems still rely on personal computers for data storage, and thus are limited by the bandwidth and cost of the computers, especially as the scale of recording increases. Here we present a novel architecture in which a digital processor receives data from an analog-to-digital converter, and writes that data directly to hard drives, without the need for a personal computer to serve as an intermediary in the DAQ process. This minimalist architecture may support exceptionally high data throughput, without incurring costs to support unnecessary hardware and overhead associated with personal computers, thus facilitating scaling of electrophysiological recording in the future. PMID:26388740

  18. A direct-to-drive neural data acquisition system

    PubMed Central

    Kinney, Justin P.; Bernstein, Jacob G.; Meyer, Andrew J.; Barber, Jessica B.; Bolivar, Marti; Newbold, Bryan; Scholvin, Jorg; Moore-Kochlacs, Caroline; Wentz, Christian T.; Kopell, Nancy J.; Boyden, Edward S.

    2015-01-01

    Driven by the increasing channel count of neural probes, there is much effort being directed to creating increasingly scalable electrophysiology data acquisition (DAQ) systems. However, all such systems still rely on personal computers for data storage, and thus are limited by the bandwidth and cost of the computers, especially as the scale of recording increases. Here we present a novel architecture in which a digital processor receives data from an analog-to-digital converter, and writes that data directly to hard drives, without the need for a personal computer to serve as an intermediary in the DAQ process. This minimalist architecture may support exceptionally high data throughput, without incurring costs to support unnecessary hardware and overhead associated with personal computers, thus facilitating scaling of electrophysiological recording in the future. PMID:26388740

  19. Inhibitors of TonB Function Identified by a High-Throughput Screen for Inhibitors of Iron Acquisition in Uropathogenic Escherichia coli CFT073

    PubMed Central

    Yep, Alejandra; McQuade, Thomas; Kirchhoff, Paul; Larsen, Martha; Mobley, Harry L. T.

    2014-01-01

    ABSTRACT The urinary tract is one of the most common sites of infection in humans, and uropathogenic Escherichia coli (UPEC) is the main causative agent of urinary tract infections. Bacteria colonizing the urinary tract face extremely low iron availability. To counteract this, UPEC expresses a wide variety of iron acquisition systems. To exploit iron acquisition in UPEC as a global target for small-molecule inhibition, we developed and carried out a whole-cell growth-based high throughput screen of 149,243 compounds. Our primary assay was carried out under iron-limiting conditions. Hits in the primary screen were assayed using two counterscreens that ruled out iron chelators and compounds that inhibit growth by means other than inhibition of iron acquisition. We determined dose-response curves under two different iron conditions and purchased fresh compounds for selected hits. After retesting dose-response relationships, we identified 16 compounds that arrest growth of UPEC only under iron-limiting conditions. All compounds are bacteriostatic and do not inhibit proton motive force. A loss-of-target strategy was employed to identify the cellular target of these inhibitors. Two compounds lost inhibitory activity against a strain lacking TonB and were shown to inhibit irreversible adsorption of a TonB-dependent bacteriophage. Our results validate iron acquisition as a target for antibacterial strategies against UPEC and identify TonB as one of the cellular targets. PMID:24570372

  20. The role of age of acquisition and language usage in early, high-proficient bilinguals: an fMRI study during verbal fluency.

    PubMed

    Perani, Daniela; Abutalebi, Jubin; Paulesu, Eraldo; Brambati, Simona; Scifo, Paola; Cappa, Stefano F; Fazio, Ferruccio

    2003-07-01

    We assessed the effects of age of acquisition and language exposure on the cerebral correlates of lexical retrieval in high-proficient, early-acquisition bilinguals. Functional MRI was used to study Spanish-Catalan bilinguals who acquired either Spanish or Catalan as a first language in the first years of life. Subjects were exposed to the second language at 3 years of age, and have used both languages in daily life since then. Subjects had a comparable level of proficiency in the comprehension of both languages. Lexical retrieval with the verbal fluency task resulted in the well-established pattern of left hemispheric activation centered on the inferior frontal region. The effect of age of acquisition was assessed by dividing the subjects into two groups, on the basis of the language acquired first (Catalan-born or Spanish-born bilinguals). Functional comparisons indicated that less extensive brain activation was associated with lexical retrieval in the language acquired earlier in life. The two groups were also different in language usage/exposure, as assessed with a specific questionnaire; in particular, the exposure to the second language (Spanish) was less intensive in the case of Catalans. This was reflected in a significant interaction, indicating a more extensive activation in Catalans during production in Spanish. Overall, these results indicate that, during a production task, both age of acquisition and language exposure affect the pattern of brain activation in bilinguals, even if both languages are acquired early and with a comparable level of proficiency.

  1. Acquisition, Retention, and Retraining: Effects of High and Low Fidelity in Training Devices. Technical Report 69-1.

    ERIC Educational Resources Information Center

    Grimsley, Douglas L.

    This study is the first in a series which was conducted under the name STRANGER III, and which was to examine trainee's long-term memory of motor skills. This phase examined the effects of varying fidelity of training devices on acquisition, retention, and reinstatement of ability to perform a 92-step procedural task. Three versions of the Section…

  2. Bandwidth enhancement of MgZnO-based MSM photodetectors by inductive gain peaking

    NASA Astrophysics Data System (ADS)

    Wang, Ping; Guo, Xinlu; Guo, Lixin; He, Jingfang; Yang, Yintang; Zhang, Zhiyong

    2016-08-01

    For high-speed optical communication applications, the bandwidth of photodetector would be a key limitation. In this work, the bandwidth property of MgZnO-based Metal-Semiconductor-Metal (MSM) photodetector considering RC and transit limitations is investigated on the basis of the series and enhanced gain peaked photodetector circuits proposed by us with different finger widths. To ensure the accuracy of parameters, the high-filed transportation characteristics of MgZnO are investigated by a three-valley ensemble Monte Carlo simulation combined with first principle calculations. The results show that the gain peaking technique, especially the enhanced gain peaking, can improve the bandwidth of MgZnO MSM photodetector to a maximum value of 61.28 GHz, corresponding to a bandwidth enhancement of 49% without undesired effects. Three-dimensional electromagnetic computation is further performed to design and simulate the on-chip-inductor. The value of the simulated inductor is approximately 0.0529 nH, which is in good agreement with the designed value of 0.0569 nH. This work benefits the development of high speed MgZnO MSM photodetector.

  3. Staged optimization algorithms based MAC dynamic bandwidth allocation for OFDMA-PON

    NASA Astrophysics Data System (ADS)

    Liu, Yafan; Qian, Chen; Cao, Bingyao; Dun, Han; Shi, Yan; Zou, Junni; Lin, Rujian; Wang, Min

    2016-06-01

    Orthogonal frequency division multiple access passive optical network (OFDMA-PON) has being considered as a promising solution for next generation PONs due to its high spectral efficiency and flexible bandwidth allocation scheme. In order to take full advantage of these merits of OFDMA-PON, a high-efficiency medium access control (MAC) dynamic bandwidth allocation (DBA) scheme is needed. In this paper, we propose two DBA algorithms which can act on two different stages of a resource allocation process. To achieve higher bandwidth utilization and ensure the equity of ONUs, we propose a DBA algorithm based on frame structure for the stage of physical layer mapping. Targeting the global quality of service (QoS) of OFDMA-PON, we propose a full-range DBA algorithm with service level agreement (SLA) and class of service (CoS) for the stage of bandwidth allocation arbitration. The performance of the proposed MAC DBA scheme containing these two algorithms is evaluated using numerical simulations. Simulations of a 15 Gbps network with 1024 sub-carriers and 32 ONUs demonstrate the maximum network throughput of 14.87 Gbps and the maximum packet delay of 1.45 ms for the highest priority CoS under high load condition.

  4. Implementation of a foveated image coding system for image bandwidth reduction

    NASA Astrophysics Data System (ADS)

    Kortum, Philip; Geisler, Wilson S.

    1996-04-01

    We have developed a preliminary version of a foveated imaging system, implemented on a general purpose computer, which greatly reduces the transmission bandwidth of images. The system is based on the fact that the spatial resolution of the human eye is space variant, decreasing with increasing eccentricity from the point of gaze. By taking advantage of this fact, it is possible to create an image that is almost perceptually indistinguishable from a constant resolution image, but requires substantially less information to code it. This is accomplished by degrading the resolution of the image so that it matches the space-variant degradation in the resolution of the human eye. Eye movements are recorded so that the high resolution region of the image can be kept aligned with the high resolution region of the human visual system. This system has demonstrated that significant reductions in bandwidth can be achieved while still maintaining access to high detail at any point in an image. The system has been tested using 256 by 256 8 bit gray scale images with a 20 degree field-of-view and eye-movement update rates of 30 Hz (display refresh was 60 Hz). users of the system have reported minimal perceptual artifacts at bandwidth reductions of up to 94.7% (a factor of 18.8). Bandwidth reduction factors of over 100 are expected once lossless compression techniques are added to the system.

  5. Phase locking and bandwidth in a gyrotron oscillator

    NASA Astrophysics Data System (ADS)

    Latham, P. E.; Granatstein, V. L.; Carmel, Y.

    1993-06-01

    For imaging radar and for satellite and space communication (e.g. NASA's deep space network), it is important that the bandwidth be as large as possible. Here we derive a formalism for computing the phase locking bandwidth that can be achieved in a gyrotron oscillator while varying the beam voltage. As an example, a second harmonic TE02/03 gyrotron is considered. For this device, the effective bandwidth can be increased by a factor of about 3 compared with the fixed voltage case by allowing the beam voltage to change together with the input locking signal.

  6. Phase locking and bandwidth in a gyrotron oscillator

    NASA Technical Reports Server (NTRS)

    Latham, P. E.; Granatstein, V. L.; Carmel, Y.

    1993-01-01

    For imaging radar and for satellite and space communication (e.g. NASA's deep space network), it is important that the bandwidth be as large as possible. Here we derive a formalism for computing the phase locking bandwidth that can be achieved in a gyrotron oscillator while varying the beam voltage. As an example, a second harmonic TE02/03 gyrotron is considered. For this device, the effective bandwidth can be increased by a factor of about 3 compared with the fixed voltage case by allowing the beam voltage to change together with the input locking signal.

  7. Ultra-broad bandwidth parametric amplification at degeneracy.

    PubMed

    Limpert, J; Aguergaray, C; Montant, S; Manek-Hönninger, I; Petit, S; Descamps, D; Cormier, E; Salin, F

    2005-09-19

    We report on a novel approach of ultra-broad bandwidth parametric amplification around degeneracy. A bandwidth of up to 400 nm centered around 800 nm is amplified in a BBO crystal by using chirped pump pulses with a bandwitdth as broad as 10 nm. A supercontinuum signal is generated in a microstructured fiber, having to first order a quadratic chirp, which is necessary to ensure temporal overlap of the interacting waves over this broad bandwidth. Furthermore, we discuss the potential of this approach for an octave-spanning parametric amplification.

  8. Study of different spectral regions and delay bandwidth relation in slow light photonic crystal waveguides.

    PubMed

    Kurt, H; Ustün, K; Ayas, L

    2010-12-20

    We investigate slow light propagation in monomode photonic crystal waveguides with different spectral features such as constant group index, high bandwidth and low group velocity dispersion. The form of the waveguide mode alters dramatically and spans three different spectral intervals by tuning the size of the boundary holes. Namely, slope of the band gap guided mode changes sign from negative to positive toward the Brillouin zone edge. In between there is a transition region where modes have nearly zero slopes. Maximum group index occurs at these turning points at the expense of high dispersion and narrow bandwidth. The apparent trade-off relationship between group index and bandwidth is revealed systematically. We show that as the radius of the innermost hole is increased above a certain value, the former one decreases and the latter one increases both exponentially but with a different ratio. The product of average group index and bandwidth is defined as a figure of merit which reaches up to a value of approximately 0.30 after a detailed parametric search. The findings of the frequency domain analysis obtained by plane wave expansion method are confirmed via finite-difference time-domain study.

  9. 47 CFR 74.736 - Emissions and bandwidth.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., AUXILIARY, SPECIAL BROADCAST AND OTHER PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.736 Emissions and bandwidth. (a) The license of a low power TV, TV translator, or...

  10. Effect of bandwidth and numerical aperture in optical scatterometry

    NASA Astrophysics Data System (ADS)

    Germer, Thomas A.; Patrick, Heather J.

    2010-03-01

    We consider the effects of finite spectral bandwidth and numerical aperture in scatterometry measurements and discuss efficient integration methods based upon Gaussian quadrature in one dimension (for spectral bandwidth averaging) and two dimensions inside a circle (for numerical aperture averaging). Provided the wavelength is not near a Wood's anomaly for the grating, we find that the resulting methods converge very quickly to a level suitable for most measurement applications. In the vicinity of a Wood's anomaly, however, the methods provide rather poor behavior. We also describe a method that can be used to extract the effective spectral bandwidth and numerical aperture for a scatterometry tool. We find that accounting for spectral bandwidth and numerical aperture is necessary to obtain satisfactory results in scatterometry.

  11. Increase of the grating coupler bandwidth with a graphene overlay

    SciTech Connect

    Cheng, Zhenzhou; Li, Zhen; Xu, Ke; Tsang, Hon Ki

    2014-03-17

    We present theoretical and experimental results that demonstrate an increase in the grating bandwidth by placing a graphene on the chip. A focusing subwavelength grating with coupling efficiency of −4.3 dB and 1 dB bandwidth of ∼60 nm was demonstrated. After a graphene sheet was transferred onto the chip, the maximum 1 dB bandwidth was increased to ∼72 nm. Experimental results are consistent with the calculated graphene induced waveguide refractive index and dispersion changes, and the bandwidth improvement may be attributed to the reduction of grating dispersion. This study may be of interest for graphene-on-silicon photonic integrated circuit applications.

  12. 47 CFR 74.736 - Emissions and bandwidth.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ..., AUXILIARY, SPECIAL BROADCAST AND OTHER PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.736 Emissions and bandwidth. (a) The license of a low power TV, TV translator, or...

  13. 47 CFR 74.736 - Emissions and bandwidth.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ..., AUXILIARY, SPECIAL BROADCAST AND OTHER PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.736 Emissions and bandwidth. (a) The license of a low power TV, TV translator, or...

  14. 47 CFR 74.736 - Emissions and bandwidth.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ..., AUXILIARY, SPECIAL BROADCAST AND OTHER PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.736 Emissions and bandwidth. (a) The license of a low power TV, TV translator, or...

  15. 47 CFR 74.736 - Emissions and bandwidth.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ..., AUXILIARY, SPECIAL BROADCAST AND OTHER PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.736 Emissions and bandwidth. (a) The license of a low power TV, TV translator, or...

  16. Napter Was Just the Start of the Bandwidth Invasion.

    ERIC Educational Resources Information Center

    Carlson, Scott

    2001-01-01

    Colleges are finding that, regardless of the court rulings against Napster, file-sharing services remain popular with students and problematic to campus networks because of the demand placed on bandwidth by music and video files. (EV)

  17. Enhancement of faba bean competitive ability by arbuscular mycorrhizal fungi is highly correlated with dynamic nutrient acquisition by competing wheat.

    PubMed

    Qiao, Xu; Bei, Shuikuan; Li, Chunjie; Dong, Yan; Li, Haigang; Christie, Peter; Zhang, Fusuo; Zhang, Junling

    2015-01-29

    The mechanistic understanding of the dynamic processes linking nutrient acquisition and biomass production of competing individuals can be instructive in optimizing intercropping systems. Here, we examine the effect of inoculation with Funneliformis mosseae on competitive dynamics between wheat and faba bean. Wheat is less responsive to mycorrhizal inoculation. Both inoculated and uninoculated wheat attained the maximum instantaneous N and P capture approximately five days before it attained the maximum instantaneous biomass production, indicating that wheat detected the competitor and responded physiologically to resource limitation prior to the biomass response. By contrast, the instantaneous N and P capture by uninoculated faba bean remained low throughout the growth period, and plant growth was not significantly affected by competing wheat. However, inoculation substantially enhanced biomass production and N and P acquisition of faba bean. The exudation of citrate and malate acids and acid phosphatase activity were greater in mycorrhizal than in uninoculated faba bean, and rhizosphere pH tended to decrease. We conclude that under N and P limiting conditions, temporal separation of N and P acquisition by competing plant species and enhancement of complementary resource use in the presence of AMF might be attributable to the competitive co-existence of faba bean and wheat.

  18. Enhancement of faba bean competitive ability by arbuscular mycorrhizal fungi is highly correlated with dynamic nutrient acquisition by competing wheat

    PubMed Central

    Qiao, Xu; Bei, Shuikuan; Li, Chunjie; Dong, Yan; Li, Haigang; Christie, Peter; Zhang, Fusuo; Zhang, Junling

    2015-01-01

    The mechanistic understanding of the dynamic processes linking nutrient acquisition and biomass production of competing individuals can be instructive in optimizing intercropping systems. Here, we examine the effect of inoculation with Funneliformis mosseae on competitive dynamics between wheat and faba bean. Wheat is less responsive to mycorrhizal inoculation. Both inoculated and uninoculated wheat attained the maximum instantaneous N and P capture approximately five days before it attained the maximum instantaneous biomass production, indicating that wheat detected the competitor and responded physiologically to resource limitation prior to the biomass response. By contrast, the instantaneous N and P capture by uninoculated faba bean remained low throughout the growth period, and plant growth was not significantly affected by competing wheat. However, inoculation substantially enhanced biomass production and N and P acquisition of faba bean. The exudation of citrate and malate acids and acid phosphatase activity were greater in mycorrhizal than in uninoculated faba bean, and rhizosphere pH tended to decrease. We conclude that under N and P limiting conditions, temporal separation of N and P acquisition by competing plant species and enhancement of complementary resource use in the presence of AMF might be attributable to the competitive co-existence of faba bean and wheat. PMID:25631933

  19. Electro-optic bandwidth manipulation of quantum light (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Karpinski, Michal; Jachura, Michal; Wright, Laura J.; Smith, Brian J.

    2016-04-01

    means of a highly dispersive chirped fiber Bragg grating. We verify the non-classicality of spectrally shifted single photons by measuring high-visibility Hong-Ou-Mandel interference using a reference single photon pulse. Spectral compression is based on the time lens principle, which requires locking optical pulses to approximately quadratic region of sinusoidal phase modulation. We utilize both 10 GHz and 40 GHz RF driving frequencies. Bandwidth compression is achieved by chirping the single photon pulse using an appropriate length of single-mode fibre and subsequently subjecting it to the action of the time lens. We verify spectral compression directly using the aforementioned spectrally-resolved heralded single photon counting method. We achieve 3-fold spectral compression of 2 nm bandwidth single photon pulses using 40 GHZ modulation frequency, and 6-fold spectral compression of 0.9 nm bandwidth single photon pulses using 10 GHz modulation frequency. Overall transmission of our set-up exceeding 30% enables practical usability of our spectral compression method which we demonstrate experimentally by showing an increased photon flux through a narrowband filter. Our results present an important contribution towards implementing quantum information processing in the spectral-temporal degree of freedom of a photon. In the context of quantum networks they present an enabling tool towards efficient photonic interfacing of different quantum information processing platforms.

  20. Multi-echo acquisition

    PubMed Central

    Posse, Stefan

    2011-01-01

    The rapid development of fMRI was paralleled early on by the adaptation of MR spectroscopic imaging (MRSI) methods to quantify water relaxation changes during brain activation. This review describes the evolution of multi-echo acquisition from high-speed MRSI to multi-echo EPI and beyond. It highlights milestones in the development of multi-echo acquisition methods, such as the discovery of considerable gains in fMRI sensitivity when combining echo images, advances in quantification of the BOLD effect using analytical biophysical modeling and interleaved multi-region shimming. The review conveys the insight gained from combining fMRI and MRSI methods and concludes with recent trends in ultra-fast fMRI, which will significantly increase temporal resolution of multi-echo acquisition. PMID:22056458

  1. Equivalent statistical bandwidths of conventional low-pass filters

    NASA Technical Reports Server (NTRS)

    Stanley, W. D.; Peterson, S. J.

    1979-01-01

    Values of the equivalent statistical bandwidths of Butterworth up to ten poles and Chebyshev up to eight poles low-pass filters for six different passband ripple levels have been computed and tabulated along with the corresponding noise bandwidths. The results obtained can be used for estimating the mean-square error resulting from power spectrum measurements employed in the sensitivity analysis of microwave radiometer systems.

  2. Laser frequency bandwidth narrowing by photorefractive two-beam coupling.

    PubMed

    Chomsky, D; Sternklar, S; Zigler, A; Jackel, S

    1992-04-01

    We present a theoretical analysis and experimental demonstration of a new method for spectral narrowing of laser radiation. The bandwidth narrowing is experienced by a laser beam subjected to a photorefractive two-beam coupling process. Contrary to the conventional method of frequency filtering by a Fabry-Perot étalon, this technique has no intrinsic finesse limitation on its resolution. A factor of 2 in frequency bandwidth narrowing is achieved with an argon-ion laser.

  3. Jefferson Lab's Distributed Data Acquisition

    SciTech Connect

    Trent Allison; Thomas Powers

    2006-05-01

    Jefferson Lab's Continuous Electron Beam Accelerator Facility (CEBAF) occasionally experiences fast intermittent beam instabilities that are difficult to isolate and result in downtime. The Distributed Data Acquisition (Dist DAQ) system is being developed to detect and quickly locate such instabilities. It will consist of multiple Ethernet based data acquisition chassis distributed throughout the seven-eights of a mile CEBAF site. Each chassis will monitor various control system signals that are only available locally and/or monitored by systems with small bandwidths that cannot identify fast transients. The chassis will collect data at rates up to 40 Msps in circular buffers that can be frozen and unrolled after an event trigger. These triggers will be derived from signals such as periodic timers or accelerator faults and be distributed via a custom fiber optic event trigger network. This triggering scheme will allow all the data acquisition chassis to be triggered simultaneously and provide a snapshot of relevant CEBAF control signals. The data will then be automatically analyzed for frequency content and transients to determine if and where instabilities exist.

  4. An Ultra-Low Bandwidth Video Transmission System

    NASA Astrophysics Data System (ADS)

    Percival, J. W.; White, R. L.

    We have developed a Progressive Video Transmission system that is suitable for use over ultra-low bandwidth connections, which we define as phone-grade connections of 28,800 bits per second (bps) or less. Our system is not designed for person-to-person videoconferencing. Rather, it is designed as a video frame browser for observatory video systems whose signals typically represent guide cameras, wavefront sensors, slit-viewing cameras, and so on. We have found that videoconferencing products are not suitable for ultra-low bandwidth connections or for video frames containing possibly significant scientific content because they often sacrifice image quality to maintain frame rate, require bandwidths of 100 kbps or more, and consume all available bandwidth between the client and server. Our system allows the user to control image quality, resolution and bandwidth on the fly, and uses a variety of compression techniques to achieve compression factors of about 5 with little apparent degradation of the images. The transmission is progressive, with the quality of each frame improving during its transmission. It supports multiple remote users, allowing each to work at their own baud and frame rates. A Tk-based GUI allows the user to control image quality and frame rate, select image size, set maximum bandwidth, save frames to disk, and change channels remotely. This system is in use at the WIYN Observatory.

  5. Scaling Mesa Indium Phosphide DHBTs to Record Bandwidths

    NASA Astrophysics Data System (ADS)

    Lobisser, Evan

    Indium phosphide heterojunction bipolar transistors are able to achieve higher bandwidths at a given feature size than transistors in the Silicon material system for a given feature size. Indium phosphide bipolar transistors demonstrate higher breakdown voltages at a given bandwidth than both Si bipolars and field effect transistors in the InP material system. The high bandwidth of InP HBTs results from both intrinsic material parameters and bandgap engineering through epitaxial growth. The electron mobility in the InGaAs base and saturation velocity in the InP collector are both approximately three times higher than their counterparts in the SiGe material system. Resistance of the base can be made very low due to the large offset in the valence band between the InP emitter and the InGaAs base, which allows the base to be doped on the order of 1020 cm-3 with negligible reduction in emitter injection efficiency. This thesis deals with type-I, NPN dual-heterojunction bipolar transistors. The emitters are InP, and the base is InGaAs. There is a thin (˜ 10 nm) n-type InGaAs "setback" region, followed by a chirped superlattice InGaAs/InAlAs grade to the InP collector. The setback, grade, and collector are all lightly doped n-type. The emitter and collector are contacted through thin (˜ 5 nm) heavily doped n-type InGaAs layers to reduce contact resistivity. The primary focus of this work is increasing the bandwidth of InP HBTs through the proportional scaling of the device dimensions, both layer thicknesses and junction areas, as well as the reduction of the contact resistivities associated with the transistor. Essentially, all RC time constants and transit times must be reduced by a factor of two to double a transistor's bandwidth. Chapter 2 describes in detail the scaling laws and design principles for high frequency bipolar transistor design. A low-stress, blanket sputter deposited composite emitter metal process was developed. Refractory metal base contacts were

  6. Note: Expanding the bandwidth of the ultra-low current amplifier using an artificial negative capacitor

    NASA Astrophysics Data System (ADS)

    Xie, Kai; Liu, Yan; Li, XiaoPing; Guo, Lixin; Zhang, Hanlu

    2016-04-01

    The bandwidth and low noise characteristics are often contradictory in ultra-low current amplifier, because an inevitable parasitic capacitance is paralleled with the high value feedback resistor. In order to expand the amplifier's bandwidth, a novel approach was proposed by introducing an artificial negative capacitor to cancel the parasitic capacitance. The theory of the negative capacitance and the performance of the improved amplifier circuit with the negative capacitor are presented in this manuscript. The test was conducted by modifying an ultra-low current amplifier with a trans-impedance gain of 50 GΩ. The results show that the maximum bandwidth was expanded from 18.7 Hz to 3.3 kHz with more than 150 times of increase when the parasitic capacitance (˜0.17 pF) was cancelled. Meanwhile, the rise time decreased from 18.7 ms to 0.26 ms with no overshot. Any desired bandwidth or rise time within these ranges can be obtained by adjusting the ratio of cancellation of the parasitic and negative capacitance. This approach is especially suitable for the demand of rapid response to weak current, such as transient ion-beam detector, mass spectrometry analysis, and fast scanning microscope.

  7. Broadband Josephson parametric amplifiers: Beyond the standard gain-bandwidth product

    NASA Astrophysics Data System (ADS)

    Roy, Tanay; Kundu, Suman; Chand, Madhavi; Vadiraj, A. M.; Ranadive, A.; Nehra, N.; Patankar, Meghan P.; Aumentado, J.; Clerk, A. A.; Vijay, R.

    Recent development of multiplexed qubit measurement schemes demand broadband quantum-limited amplifiers to enable high fidelity readout with minimal resources. We present a simple technique to enhance the bandwidth of a resonator based Josephson Parametric Amplifier (JPA) beyond the standard gain-bandwidth product. This is achieved by introducing a positive linear slope in the imaginary component of the input impedance seen by the JPA using a λ / 2 transformer. Our theoretical model predicts an extremely flat gain profile with a bandwidth enhancement proportional to the square root of the amplitude gain. Experimentally, we achieved a nearly flat 20 dB gain profile over a 640 MHz band, with a mean 1-dB compression point of -110 dBm along with nearly quantum-limited noise performance. The results are in excellent agreement with our theoretical model. We will then discuss strategies to further enhance the performance in terms of bandwidth and dynamic range of the JPA. Finally, we will consider the applicability of our technique to different parametric pumping methods and other parametric amplifier designs as well.

  8. Note: Expanding the bandwidth of the ultra-low current amplifier using an artificial negative capacitor.

    PubMed

    Xie, Kai; Liu, Yan; Li, XiaoPing; Guo, Lixin; Zhang, Hanlu

    2016-04-01

    The bandwidth and low noise characteristics are often contradictory in ultra-low current amplifier, because an inevitable parasitic capacitance is paralleled with the high value feedback resistor. In order to expand the amplifier's bandwidth, a novel approach was proposed by introducing an artificial negative capacitor to cancel the parasitic capacitance. The theory of the negative capacitance and the performance of the improved amplifier circuit with the negative capacitor are presented in this manuscript. The test was conducted by modifying an ultra-low current amplifier with a trans-impedance gain of 50 GΩ. The results show that the maximum bandwidth was expanded from 18.7 Hz to 3.3 kHz with more than 150 times of increase when the parasitic capacitance (∼0.17 pF) was cancelled. Meanwhile, the rise time decreased from 18.7 ms to 0.26 ms with no overshot. Any desired bandwidth or rise time within these ranges can be obtained by adjusting the ratio of cancellation of the parasitic and negative capacitance. This approach is especially suitable for the demand of rapid response to weak current, such as transient ion-beam detector, mass spectrometry analysis, and fast scanning microscope. PMID:27131718

  9. Performance of reduced bit-depth acquisition for optical frequency domain imaging.

    PubMed

    Goldberg, Brian D; Vakoc, Benjamin J; Oh, Wang-Yuhl; Suter, Melissa J; Waxman, Sergio; Freilich, Mark I; Bouma, Brett E; Tearney, Guillermo J

    2009-09-14

    High-speed optical frequency domain imaging (OFDI) has enabled practical wide-field microscopic imaging in the biological laboratory and clinical medicine. The imaging speed of OFDI, and therefore the field of view, of current systems is limited by the rate at which data can be digitized and archived rather than the system sensitivity or laser performance. One solution to this bottleneck is to natively digitize OFDI signals at reduced bit depths, e.g., at 8-bit depth rather than the conventional 12-14 bit depth, thereby reducing overall bandwidth. However, the implications of reduced bit-depth acquisition on image quality have not been studied. In this paper, we use simulations and empirical studies to evaluate the effects of reduced depth acquisition on OFDI image quality. We show that image acquisition at 8-bit depth allows high system sensitivity with only a minimal drop in the signal-to-noise ratio compared to higher bit-depth systems. Images of a human coronary artery acquired in vivo at 8-bit depth are presented and compared with images at higher bit-depth acquisition.

  10. PTTI-aided ephemeris calculation and rapid data link acquisition for manned space flight

    NASA Technical Reports Server (NTRS)

    Anderman, Alfred

    1993-01-01

    Complexity of future manned space flight mission control can be significantly reduced by integrating GPS, the PTTI source, into telemetry, tracking, and command (TT&C). Future telecommunications, space tracking electronic intelligence, metrology, navigation, and data acquisition will thereby be served, including: on-board ephemeris determination, reduced synchronization time for time division multiple access (TDMA) links, and in-flight clock calibration, increasing on-board autonomy and reducing ground support costs. Manned space transportation through the first quarter of the 21st century will probably depend on a mix of vehicles, including the Advanced Manned Launch System (AMLS), the Personnel Launch System (PLS), and continued use of the Shuttle Fleet. Precise Ephemeris is important on-board for mission success, status monitoring, also for rendezvous and docking. Use of GPS can eliminate ground based tracking/processing, enhancing autonomy and reducing communications bandwidth. GPS time can simplify complicated functions used in bandwidth efficient time division multiple access (TDMA) communications, such as: precise and realtime synchronization of receive reference timing, transmit-timing and acquisition control, unique synchronization word (UW) detection, and elastic buffering. High clock accuracy provides increased signal-to-noise (S/N) ratio during acquisition, permitting narrower acquisition frequency and time windows. Spaceborne systems requirements to provide capabilities such as: refinement of the GEM-72 gravity model based on satellite tracking observations from ATS-6 to GEOS-3, relativistic clock experiments, NASA crustal dynamics program for developing space geodetic techniques to study the earth's crust, its gravity field, and earthquake mechanisms, and multi-disciplinary space geodetic tracking for studying global climatic changes are also reviewed.

  11. MATLAB implementation of a dynamic clamp with bandwidth of >125 kHz capable of generating I Na at 37 °C.

    PubMed

    Clausen, Chris; Valiunas, Virginijus; Brink, Peter R; Cohen, Ira S

    2013-04-01

    We describe the construction of a dynamic clamp with a bandwidth of >125 kHz that utilizes a high-performance, yet low-cost, standard home/office PC interfaced with a high-speed (16 bit) data acquisition module. High bandwidth is achieved by exploiting recently available software advances (code-generation technology and optimized real-time kernel). Dynamic-clamp programs are constructed using Simulink, a visual programming language. Blocks for computation of membrane currents are written in the high-level MATLAB language; no programming in C is required. The instrument can be used in single- or dual-cell configurations, with the capability to modify programs while experiments are in progress. We describe an algorithm for computing the fast transient Na(+) current (I Na) in real time and test its accuracy and stability using rate constants appropriate for 37 °C. We then construct a program capable of supplying three currents to a cell preparation: I Na, the hyperpolarizing-activated inward pacemaker current (I f) and an inward-rectifier K(+) current (I K1). The program corrects for the IR drop due to electrode current flow and also records all voltages and currents. We tested this program on dual patch-clamped HEK293 cells where the dynamic clamp controls a current-clamp amplifier and a voltage-clamp amplifier controls membrane potential, and current-clamped HEK293 cells where the dynamic clamp produces spontaneous pacing behavior exhibiting Na(+) spikes in otherwise passive cells. PMID:23224681

  12. Acquisition of i.v. cocaine self-administration in adolescent and adult male rats selectively bred for high and low saccharin intake.

    PubMed

    Perry, Jennifer L; Anderson, Marissa M; Nelson, Sarah E; Carroll, Marilyn E

    2007-05-16

    Adolescence and excessive intake of saccharin have each been previously associated with enhanced vulnerability to drug abuse. In the present study, we focused on the relationship between these two factors using male adolescent and adult rats selectively bred for high (HiS) and low (LoS) levels of saccharin intake. On postnatal day 25 (adolescents) or 150 (adults), rats were implanted with an intravenous catheter and trained to self-administer cocaine (0.4 mg/kg) using an autoshaping procedure that consisted of two 6-h sessions. In the first 6 h, rats were given non-contingent cocaine infusions at random intervals 10 times per hour, and during the second 6-h session, rats were allowed to self-administer cocaine under a fixed ratio 1 (FR 1) lever-response contingency. Acquisition was defined as a total of at least 250 infusions over 5 consecutive days, and rats were given 30 days to meet the acquisition criterion. Subsequently, saccharin phenotype scores were determined by comparing 24-h saccharin and water consumption in two-bottle tests to verify HiS/LoS status. Adolescent LoS rats had a faster rate of acquisition of cocaine self-administration than adult LoS rats; however, adolescent and adult HiS rats acquired at the same rate. Both HiS and LoS adolescents had significantly higher saccharin phenotype scores than HiS and LoS adults, respectively. Additionally, saccharin score was negatively correlated with the number of days to meet the acquisition criterion for cocaine self-administration, but this was mostly accounted for by the HiS adolescents. These results suggest that during adolescence, compared with adulthood, rats have both an increased avidity for sweets and vulnerability to initiate drug abuse.

  13. Applying 'Sequential Windowed Acquisition of All Theoretical Fragment Ion Mass Spectra' (SWATH) for systematic toxicological analysis with liquid chromatography-high-resolution tandem mass spectrometry.

    PubMed

    Arnhard, Kathrin; Gottschall, Anna; Pitterl, Florian; Oberacher, Herbert

    2015-01-01

    Liquid chromatography-tandem mass spectrometry (LC-MS/MS) has become an indispensable analytical technique in clinical and forensic toxicology for detection and identification of potentially toxic or harmful compounds. Particularly, non-target LC-MS/MS assays enable extensive and universal screening requested in systematic toxicological analysis. An integral part of the identification process is the generation of information-rich product ion spectra which can be searched against libraries of reference mass spectra. Usually, 'data-dependent acquisition' (DDA) strategies are applied for automated data acquisition. In this study, the 'data-independent acquisition' (DIA) method 'Sequential Windowed Acquisition of All Theoretical Fragment Ion Mass Spectra' (SWATH) was combined with LC-MS/MS on a quadrupole-quadrupole-time-of-flight (QqTOF) instrument for acquiring informative high-resolution tandem mass spectra. SWATH performs data-independent fragmentation of all precursor ions entering the mass spectrometer in 21m/z isolation windows. The whole m/z range of interest is covered by continuous stepping of the isolation window. This allows numerous repeat analyses of each window during the elution of a single chromatographic peak and results in a complete fragment ion map of the sample. Compounds and samples typically encountered in forensic casework were used to assess performance characteristics of LC-MS/MS with SWATH. Our experiments clearly revealed that SWATH is a sensitive and specific identification technique. SWATH is capable of identifying more compounds at lower concentration levels than DDA does. The dynamic range of SWATH was estimated to be three orders of magnitude. Furthermore, the >600,000 SWATH spectra matched led to only 408 incorrect calls (false positive rate = 0.06 %). Deconvolution of generated ion maps was found to be essential for unravelling the full identification power of LC-MS/MS with SWATH. With the available software, however, only semi

  14. Gain-Bandwidth Product Optimization of Heterostructure Avalanche Photodiodes

    NASA Astrophysics Data System (ADS)

    Kwon, Oh-Hyun; Hayat, Majeed M.; Campbell, Joe C.; Saleh, Bahaa E. A.; Teich, Malvin C.

    2005-05-01

    A generalized history-dependent recurrence theory for the time-response analysis is derived for avalanche photodiodes with multilayer, heterojunction multiplication regions. The heterojunction multiplication region considered consists of two layers: a high-bandgap Al_0.6 Ga_0.4 As energy-buildup layer, which serves to heat up the primary electrons, and a GaAs layer, which serves as the primary avalanching layer. The model is used to optimize the gain-bandwidth product (GBP) by appropriate selection of the width of the energy-buildup layer for a given width of the avalanching layer. The enhanced GBP is a direct consequence of the heating of primary electrons in the energy-buildup layer, which results in a reduced first dead space for the carriers that are injected into the avalanche-active GaAs layer. This effect is akin to the initial-energy effect previously shown to enhance the excess-noise factor characteristics in thin avalanche photodiodes (APDs). Calculations show that the GBP optimization is insensitive to the operational gain and the optimized APD also minimizes the excess-noise factor.

  15. Antenna array bandwidth enhancement using polymeric nanocomposite substrate

    NASA Astrophysics Data System (ADS)

    Muhamad, W. A. W.; Ngah, R.; Jamlos, M. F.; Soh, P. J.; Jamlos, M. A.; Lago, H.

    2016-04-01

    A 4 × 2 array antenna is developed using a new nanocomposite polymeric magneto-dielectric substrate. The permittivity and permeability factors have been accounted in designing the proposed array antenna at the frequency of 2.6 GHz. A pure polydimethylsiloxane (P-PDMS) (ɛ r = 2.7) solution is mixed with ferrite III oxide (μ r = 1.2) to generate this new nanocomposite polymeric magneto-dielectric (NPMD) substrate. The NPMD surface is then hardened and located in between two P-PDMS layers. The 4 × 2 radiating elements are immersed to the top of P-PDMS layer, while SMA coaxial feeder is fed from underneath the ground layer. This sealing technique enabled the proposed antenna to be waterproof and flexible. This combination contributes to bandwidth enhancement of 52.65 %, size miniaturization of 176 × 156 mm2 and high gain of 10.8 dB. The measured results show a good agreement with simulations.

  16. Review of single transient oscillographic recorders with gigahertz bandwidth

    SciTech Connect

    Campbell, D.E.

    1982-10-20

    In laser driven inertial confinement fusion research, at Livermore, we are diagnosing many phenomena that occur in a time frame that exceeds the capabilities of even the most advanced, present day oscillographic recording instruments. Many of the by-products of the interaction between the laser beam and fuel pellet are monitored to determine the specifics of the fusion process. By the use of appropriate detectors, we convert the information contained in the radiated by-products to electrical signals which are recorded on high bandwidth oscillographic recorders. Our present range of recording capabilities for one x-ray diagnostic measurement in use at Livermore is shown. A commonly used configuration consists of an XRD-31 x-ray detector connected to a direct access Tektronix R7912 transient digitizer using 1/2 in. diameter air dielectric coaxial cable. This configuration gives a system fwhm of approximately 335 ps. Our premier configuration, on the other hand, consists of an improved response detector and a French Thomson-CSF TSN-660 oscilloscope with a shorter length of coaxial cable (typically 20 feet). The system fwhm in this case is less than 120 ps which is our fastest oscillographic recording system at the present time.

  17. Using Assistive Technology to Increase Vocabulary Acquisition and Engagement for Students with Learning Disabilities in the High School Science Classroom

    NASA Astrophysics Data System (ADS)

    Slemrod, Tal

    There is a growing recognition of the importance and effectiveness of instruction in the STEM subjects, including science. The movement towards increased requirements and expectations in science presents a challenge to both students and teachers as many students with Learning Disabilities (LD) often particularly struggle in their science classes. The purpose of this study was to investigate the use of an assistive technology (AT) intervention targeting the acquisition of science vocabulary for adolescents with LD in a general education secondary biology classroom. Participants for this study included 3 secondary students with LD who were enrolled in a biology class. An alternating treatment design was used to compare the effects of a keyword mnemonic vocabulary intervention via index cards or iPod touch on student, vocabulary acquisition, academic engagement and disruptive behavior. All students' acquired the content vocabulary equally well during both conditions. When using the AT, students' engagement increased compared to baseline conditions. It was clear that the students had a strong interest in using AT to increase their grades and engagement, however the teachers had little access and training on using AT to support their students with disabilities.

  18. Bandwidth control of wavelength-selective uncooled infrared sensors using two-dimensional plasmonic absorbers

    NASA Astrophysics Data System (ADS)

    Ogawa, Shinpei; Fujisawa, Daisuke; Kimata, Masafumi

    2016-05-01

    Although standard uncooled infrared (IR) sensors can be used to record information such as the shape, position, and average radiant intensity of objects, these devices cannot capture color (that is, wavelength) data. Achieving wavelength selectivity would pave the way for the development of advanced uncooled IR sensors capable of providing color information as well as multi-color image sensors that would have significant advantages in applications such as fire detection, gas analysis, hazardous material recognition, and biological analysis. We have previously demonstrated an uncooled IR sensor incorporating a two-dimensional plasmonic absorber (2D PLA) that exhibits wavelength selectivity over a wide range in the mid- and long-IR regions. This PLA has a 2D Au-based periodic array of dimples, in which surface plasmon modes are induced and wavelength-selective absorption occurs. However, the dependence of the absorption bandwidth on certain structural parameters has yet to be clarified. The bandwidth of such devices is a vital factor when considering the practical application of these sensors to tasks such as gas detection. In the present study, control of the bandwidth was theoretically investigated using a rigorous coupled wave analysis approach. It is demonstrated that the dimple sidewall structure has a significant impact on the bandwidth and can be used to control both narrow- and broadband absorption. Increasing the sidewall slope was found to decrease the bandwidth due to suppression of cavity-mode resonance in the depth direction of the dimples. These results will contribute to the development of high-resolution, wavelength-selective uncooled IR sensors.

  19. Wide-bandwidth high-resolution search for extraterrestrial intelligence

    NASA Technical Reports Server (NTRS)

    Horowitz, Paul

    1992-01-01

    This interim report summarizes the research accomplished during the initial 6-month period of the grant. Activities associated with antenna configurations, the channelizing downconverter, the fast Fourier transform array, the DSP (digital signal processing) array, and the backend and UNIX workstation are discussed. Publications submitted during the reporting period are listed.

  20. High speed, real-time, camera bandwidth converter

    DOEpatents

    Bower, Dan E; Bloom, David A; Curry, James R

    2014-10-21

    Image data from a CMOS sensor with 10 bit resolution is reformatted in real time to allow the data to stream through communications equipment that is designed to transport data with 8 bit resolution. The incoming image data has 10 bit resolution. The communication equipment can transport image data with 8 bit resolution. Image data with 10 bit resolution is transmitted in real-time, without a frame delay, through the communication equipment by reformatting the image data.

  1. Integrated Solar Array and Reflectarray Antenna for High Bandwidth Cubesats

    NASA Technical Reports Server (NTRS)

    Lewis, Dorothy; Martinez, Andres; Petro, Andrew

    2015-01-01

    The Integrated Solar Array and Reflectarray Antenna (ISARA) mission will demonstrate a reflectarray antenna that increases downlink data rates for Cube- Sats from the existing baseline rate of 9.6 kilobits per second (kbps) to more than 100 megabits per second (Mbps). The ISARA spacecraft is slated for launch no earlier than Dec. 1, 2015.

  2. Wide-bandwidth high-resolution search for extraterrestrial intelligence

    NASA Technical Reports Server (NTRS)

    Horowitz, Paul

    1992-01-01

    Research accomplished in the following areas is discussed: the antenna configuration; HEMT low-noise amplifiers; the downconverter; the Fast Fourier Transform Array; the backend array; and the backend and workstation.

  3. High bandwidth on-chip capacitive tuning of microtoroid resonators.

    PubMed

    Baker, Christopher G; Bekker, Christiaan; McAuslan, David L; Sheridan, Eoin; Bowen, Warwick P

    2016-09-01

    We report on the design, fabrication and characterization of silica microtoroid based cavity opto-electromechanical systems (COEMS). Electrodes patterned onto the microtoroid resonators allow for rapid capacitive tuning of the optical whispering gallery mode resonances while maintaining their ultrahigh quality factor, enabling applications such as efficient radio to optical frequency conversion, optical routing and switching applications. PMID:27607646

  4. Wide-bandwidth high-resolution search for extraterrestrial intelligence

    NASA Technical Reports Server (NTRS)

    Horowitz, Paul

    1993-01-01

    A third antenna was added to the system. It is a terrestrial low-gain feed, to act as a veto for local interference. The 3-chip design for a 4 megapoint complex FFT was reduced to finished working hardware. The 4-Megachannel circuit board contains 36 MByte of DRAM, 5 CPLDs, the three large FFT ASICs, and 74 ICs in all. The Austek FDP-based Spectrometer/Power Accumulator (SPA) has now been implemented as a 4-layer printed circuit. A PC interface board has been designed and together with its associated user interface and control software allows an IBM compatible computer to control the SPA board, and facilitates the transfer of spectra to the PC for display, processing, and storage. The Feature Recognizer Array cards receive the stream of modulus words from the 4M FFT cards, and forward a greatly thinned set of reports to the PC's in whose backplane they reside. In particular, a powerful ROM-based state-machine architecture has been adopted, and DRAM has been added to permit integration modes when tracking or reobserving source candidates. The general purpose (GP) array consists of twenty '486 PC class computers, each of which receives and processes the data from a feature extractor/correlator board set. The array performs a first analysis on the provided 'features' and then passes this information on to the workstation. The core workstation software is now written. That is, the communication channels between the user interface, the backend monitor program and the PC's have working software.

  5. Ambient and Cryogenic, Decade Bandwidth, Low Noise Receiving System for Radio Astronomy Using Sinuous Antenna

    NASA Astrophysics Data System (ADS)

    Gawande, Rohit Sudhir

    of the composite structure resulting in frequency dependent impedance variations. We demonstrate, using simulations and measurements, how the return loss can be improved by modifying the sinuous geometry. The feed-LNA combination is characterized for important properties such as return loss, system noise, far field beam patterns including cross-polarization over a wide frequency range. The system is developed as a feed for a parabolic reflector. The overall system performance is calculated in terms of the A/Tsys ratio. A cryogenic version would have a direct impact on specialized observing applications requiring large instantaneous bandwidths with high sensitivity. A novel cryogenic implementation of this system is demonstrated using a Stirling cycle, one-stage refrigerator. The cryocooler offers advantages like low cost, light weight, small size, low power consumption, and does not require routine maintenance. The higher antenna input impedance and a balanced feeding method for the sinuous antenna offers a unique set of challenges when developing a cryogenic system.

  6. Effective bandwidth guaranteed routing schemes for MPLS traffic engineering

    NASA Astrophysics Data System (ADS)

    Wang, Bin; Jain, Nidhi

    2001-07-01

    In this work, we present online algorithms for dynamic routing bandwidth guaranteed label switched paths (LSPs) where LSP set-up requests (in terms of a pair of ingress and egress routers as well as its bandwidth requirement) arrive one by one and there is no a priori knowledge regarding future LSP set-up requests. In addition, we consider rerouting of LSPs in this work. Rerouting of LSPs has not been well studied in previous work on LSP routing. The need of LSP rerouting arises in a number of ways: occurrence of faults (link and/or node failures), re-optimization of existing LSPs' routes to accommodate traffic fluctuation, requests with higher priorities, and so on. We formulate the bandwidth guaranteed LSP routing with rerouting capability as a multi-commodity flow problem. The solution to this problem is used as the benchmark for comparing other computationally less costly algorithms studied in this paper. Furthermore, to more efficiently utilize the network resources, we propose online routing algorithms which route bandwidth demands over multiple paths at the ingress router to satisfy the customer requests while providing better service survivability. Traffic splitting and distribution over the multiple paths are carefully handled using table-based hashing schemes while the order of packets within a flow is preserved. Preliminary simulations are conducted to show the performance of different design choices and the effectiveness of the rerouting and multi-path routing algorithms in terms of LSP set-up request rejection probability and bandwidth blocking probability.

  7. Multibeam Advisory Committee (MAC) - Three Years of Working Towards the Consistent Acquisition of High Quality Multibeam Echosounder Data Across the US Academic Fleet

    NASA Astrophysics Data System (ADS)

    Johnson, P. D.; Beaudoin, J. D.; Ferrini, V. L.

    2014-12-01

    In 2010 the National Science Foundation (NSF) held a meeting to address the variability in quality of multibeam echosounder (MBES) data for ships of the US Academic Fleet. The participants of this meeting identified that there was a strong need to coordinate operational efforts for multibeam data acquisition across all vessels of the fleet. To address this need, the University of New Hampshire's Center for Coastal and Ocean Mapping joined with Lamont-Doherty Earth Observatory in submitting a proposal to NSF to form the Multibeam Advisory Committee (MAC), which was funded in the fall of 2011. The MAC through the last three years has assembled a team of experts who have been called upon to respond to questions about MBES data acquisition and data quality, conduct shipboard assessments of MBES systems, create documentation supporting best practices for multibeam acquisition and data workflow, and to develop tools to support both data acquisition and quality assessment. Tools and techniques developed through the MAC include: SVP Editor - a graphical display and editing program for SVP, CTD, XBT, and XSV data. This program integrates directly with multibeam acquisition software to both receive navigation and depth information, used during the processing of the sound velocity data, and also has the ability to send edited and processed cast directly to the sounder. MBES Accuracy and Swath Performance Tools - tools which can assess both the accuracy of MBES bathymetric data as compared to a reference surface grid and to examine swath width performance of MBES systems as a function of depth. Remote Patch Test Support - the MAC provides patch test site selection, detailed execution plans, and tools to support the transmittal of a downsized raw MBES data files from ships over satellite in order to determine the angular offset values (pitch, heading, and roll) for MBES systems with no MAC personnel on board. Built In Self Test (BIST) Evaluation Tools - tools which can plot and

  8. Design of a smart material electro-hydraulic actuator with improved frequency bandwidth

    NASA Astrophysics Data System (ADS)

    Larson, John P.; Dapino, Marcelo J.

    2012-04-01

    Smart material electro-hydraulic actuators utilize fluid rectification by one-way valves to convert the small, high-frequency, high-force motions of smart materials such as piezoelectrics and magnetostrictives into useful motions of a hydraulic cylinder. These actuators have potential to replace centralized hydraulic pumps and lines with lightweight, compact, power-by-wire systems. This paper presents the design and testing of an improved actuator system. To increase the frequency bandwidth of operation, a lumped-parameter model is developed and validated based on experimental study of a pump with a performance capacity of 18.4 W. The critical parameters for pump performance are identified and their effect on pump performance assessed. The geometry of the hydraulic manifold that integrates the smart material pump and the output hydraulic cylinder is found to be critical for determining the effective system bandwidth.

  9. Narrow bandwidth Thomson photon source development using Laser-Plasma Accelerators

    NASA Astrophysics Data System (ADS)

    Geddes, C. G. R.; Steinke, S.; Tsai, H.-E.; Rykovanov, S. G.; Vay, J.-L.; Bonatto, A.; Benedetti, C.; Schroeder, C. B.; Esarey, E.; Friedman, A.; Grote, D. P.; Leemans, W. P.

    2015-11-01

    Compact, high-quality photon sources at MeV energies are being developed based on Laser-Plasma Accelerators (LPAs). Simulations are presented on production of controllable narrow bandwidth sources using the beam and plasma capabilities of LPAs. An independent scattering laser, combined with appropriate pulse shaping and laser guiding is important to realize high photon yield. Plasma optics are described to tailor beam divergence in cm-scale distances, reducing photon source bandwidth. The LPA can further be used to de-accelerate the electron beam after photon production to reduce undesired radiation. Combination of laser driven and beam driven deceleration is presented to reduce residual beam energy, as is important for a laboratory or field operable source. Design of experiments and laser capabilities to combine these elements will be presented, towards a compact photon source system.

  10. A scalable parallel open architecture data acquisition system for low to high rate experiments, test beams and all SSC (Superconducting Super Collider) detectors

    SciTech Connect

    Barsotti, E.; Booth, A.; Bowden, M.; Swoboda, C. ); Lockyer, N.; VanBerg, R. )

    1989-12-01

    A new era of high-energy physics research is beginning requiring accelerators with much higher luminosities and interaction rates in order to discover new elementary particles. As a consequences, both orders of magnitude higher data rates from the detector and online processing power, well beyond the capabilities of current high energy physics data acquisition systems, are required. This paper describes a new data acquisition system architecture which draws heavily from the communications industry, is totally parallel (i.e., without any bottlenecks), is capable of data rates of hundreds of GigaBytes per second from the detector and into an array of online processors (i.e., processor farm), and uses an open systems architecture to guarantee compatibility with future commercially available online processor farms. The main features of the system architecture are standard interface ICs to detector subsystems wherever possible, fiber optic digital data transmission from the near-detector electronics, a self-routing parallel event builder, and the use of industry-supported and high-level language programmable processors in the proposed BCD system for both triggers and online filters. A brief status report of an ongoing project at Fermilab to build the self-routing parallel event builder will also be given in the paper. 3 figs., 1 tab.

  11. Adaptive Broadcasting Mechanism for Bandwidth Allocation in Mobile Services

    PubMed Central

    Horng, Gwo-Jiun; Wang, Chi-Hsuan; Chou, Chih-Lun

    2014-01-01

    This paper proposes a tree-based adaptive broadcasting (TAB) algorithm for data dissemination to improve data access efficiency. The proposed TAB algorithm first constructs a broadcast tree to determine the broadcast frequency of each data and splits the broadcast tree into some broadcast wood to generate the broadcast program. In addition, this paper develops an analytical model to derive the mean access latency of the generated broadcast program. In light of the derived results, both the index channel's bandwidth and the data channel's bandwidth can be optimally allocated to maximize bandwidth utilization. This paper presents experiments to help evaluate the effectiveness of the proposed strategy. From the experimental results, it can be seen that the proposed mechanism is feasible in practice. PMID:25057509

  12. Bandwidth analysis of all-optical turbo-switch

    NASA Astrophysics Data System (ADS)

    Zhou, Peng; Yang, Xuelin; Hu, Xiaonan; Hu, Weisheng

    2015-01-01

    We propose and develop a frequency-domain model to analyze the bandwidth of all-optical turbo-switch. The model has taken the spatial inhomogeneity of semiconductor optical amplifier (SOA) into consideration for the first time. The simulations based on the model show that the 3-dB bandwidth of turbo-switch could reach up to ~270 GHz when the second SOA is oversaturated. However, the overshoot will be higher, which may result in the distortion of the output signal. There is a trade-off between the bandwidth and the flatness of frequency response characteristics for turbo-switch operation. In addition, the optimum position of the delay-interferometer (DI) is investigated, showing that the level of the overshoot is relatively lower if the DI is placed between the two SOAs.

  13. Gain/bandwidth predictions for travelling-wave gyrotron

    NASA Astrophysics Data System (ADS)

    Sangster, A. J.

    1980-10-01

    Small signal gain computations based on a Pierce description of the traveling-wave gyrotron have been performed for cases involving beam voltages in the range 70-300 kV. Interactions at both the first and the second harmonics of the cyclotron resonance frequency have been considered in order to identify a range of operating parameters for the gyro-traveling-wave amplifier configuration which will potentially produce gain and bandwidth figures of significance to radar and communication systems operating at millimeter-wave frequencies. It is shown that when operated fundamentally and well away from cutoff, the gyro-traveling-wave amplifier can be magnetically tuned over a wide frequency range, with instantaneous bandwidths in the range 4-8% depending on the beam voltage; at voltages in excess of 200 kV, instantaneous bandwidths approaching 10% can be achieved.

  14. Adaptive broadcasting mechanism for bandwidth allocation in mobile services.

    PubMed

    Horng, Gwo-Jiun; Wang, Chi-Hsuan; Chou, Chih-Lun

    2014-01-01

    This paper proposes a tree-based adaptive broadcasting (TAB) algorithm for data dissemination to improve data access efficiency. The proposed TAB algorithm first constructs a broadcast tree to determine the broadcast frequency of each data and splits the broadcast tree into some broadcast wood to generate the broadcast program. In addition, this paper develops an analytical model to derive the mean access latency of the generated broadcast program. In light of the derived results, both the index channel's bandwidth and the data channel's bandwidth can be optimally allocated to maximize bandwidth utilization. This paper presents experiments to help evaluate the effectiveness of the proposed strategy. From the experimental results, it can be seen that the proposed mechanism is feasible in practice.

  15. Correlation and image compression for limited-bandwidth CCD.

    SciTech Connect

    Thompson, Douglas G.

    2005-07-01

    As radars move to Unmanned Aerial Vehicles with limited-bandwidth data downlinks, the amount of data stored and transmitted with each image becomes more significant. This document gives the results of a study to determine the effect of lossy compression in the image magnitude and phase on Coherent Change Detection (CCD). We examine 44 lossy compression types, plus lossless zlib compression, and test each compression method with over 600 CCD image pairs. We also derive theoretical predictions for the correlation for most of these compression schemes, which compare favorably with the experimental results. We recommend image transmission formats for limited-bandwidth programs having various requirements for CCD, including programs which cannot allow performance degradation and those which have stricter bandwidth requirements at the expense of CCD performance.

  16. Maximum bandwidth snapshot channeled imaging polarimeter with polarization gratings

    NASA Astrophysics Data System (ADS)

    LaCasse, Charles F.; Redman, Brian J.; Kudenov, Michael W.; Craven, Julia M.

    2016-05-01

    Compact snapshot imaging polarimeters have been demonstrated in literature to provide Stokes parameter estimations for spatially varying scenes using polarization gratings. However, the demonstrated system does not employ aggressive modulation frequencies to take full advantage of the bandwidth available to the focal plane array. A snapshot imaging Stokes polarimeter is described and demonstrated through results. The simulation studies the challenges of using a maximum bandwidth configuration for a snapshot polarization grating based polarimeter, such as the fringe contrast attenuation that results from higher modulation frequencies. Similar simulation results are generated and compared for a microgrid polarimeter. Microgrid polarimeters are instruments where pixelated polarizers are superimposed onto a focal plan array, and this is another type of spatially modulated polarimeter, and the most common design uses a 2x2 super pixel of polarizers which maximally uses the available bandwidth of the focal plane array.

  17. Evaluation of a High Resolving Power Time-of-Flight Mass Spectrometer for Drug Analysis in Terms of Resolving Power and Acquisition Rate

    NASA Astrophysics Data System (ADS)

    Pelander, Anna; Decker, Petra; Baessmann, Carsten; Ojanperä, Ilkka

    2011-02-01

    Liquid chromatography time-of-flight mass spectrometry (LC-TOFMS) is applied increasingly to various fields of small molecule analysis. The moderate resolving power (RP) of standard TOFMS instruments poses a risk of false negative results when complex biological matrices are to be analyzed. In this study, the performance of a high resolving power TOFMS instrument (maXis by Bruker Daltonik, Bremen, Germany) was evaluated for drug analysis. By flow injection analysis of critical drug mixtures, including a total of 17 compounds with nominal masses of 212-415 Da and with mass differences of 8.8-23.5 mDa, RP varied from 34,400 to 51,900 (FWHM). The effect of acquisition rate on RP, mass accuracy, and isotopic pattern fit was studied by applying 1, 2, 5, 10, and 20 Hz acquisition rates in a 16 min gradient elution LC separation. All three variables were independent of the acquisition rate, with an average mass accuracy and isotopic pattern fit factor (mSigma) of 0.33 ppm and 5.9, respectively. The average relative standard deviation of RP was 1.8%, showing high repeatability. The performance was tested further with authentic urine extracts containing a co-eluting compound pair with a nominal mass of 296 Da and an 11.2 mDa mass difference. The authentic sample components were readily resolved and correctly identified by the automated data analysis. The average RP, mass accuracy, and isotopic pattern fit were 36,600, 0.9 ppm, and 7.3 mSigma, respectively.

  18. Towards broad-bandwidth polarization-independent nanostrip waveguide ring resonators.

    PubMed

    Erdmanis, M; Karvonen, L; Säynätjoki, A; Tu, X; Liow, T Y; Lo, Q G; Vänskä, O; Honkanen, S; Tittonen, I

    2013-04-22

    We demonstrate a new method for accessing the broad-bandwidth polarization-independent operation of a microring resonator based on the standard photonic nanostrip waveguides. The method employs the selective application of atomic layer deposition to form highly uniform TiO(2) overlayers with the specific dispersion properties. The wide operation window is achieved by matching the wavelength dependencies of the free spectral ranges of the two orthogonal polarizations. PMID:23609703

  19. Wide bandwidth SIN tunnel junction thermometers for mesoscopic calorimetry and bolometry

    NASA Astrophysics Data System (ADS)

    Schmidt, D. R.; Yung, C. S.; Cleland, A. N.

    2003-03-01

    Thermodynamic measurements of mesoscopic devices require sensitive thermometers which are small enough to allow integration with nanostructures. Superconductor-insulator-normal metal (SIN) tunnel junctions meet these stringent requirements. We have achieved high bandwidth ( ˜10 MHz) readout of the inherently resistive SIN thermometer by embedding the junction in an LC resonator (f_res ˜ 350 MHz). We will discuss our implementation of this new technology and the implications for radio-frequency calorimetry of mesocopic devices and bolometetry.

  20. 47 CFR 74.462 - Authorized bandwidth and emissions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Authorized bandwidth(kHz) Maximum frequency deviation 1 (kHz) Type of emission 2 MHz: 25.87 to 26.0326.07 to....8625 25-50 10 450.900, 450.950 455.900, 455.950 50-100 35 1 Applies where F1A, F1B, F1D, F1E, F2A, F2B... aircraft, or to use a bandwidth in excess of 30 kHz and maximum deviation exceeding 5 kHz 4 For...