Science.gov

Sample records for low-noise two-dimensional amplifier

  1. Low noise tuned amplifier

    NASA Technical Reports Server (NTRS)

    Kleinberg, L. L. (Inventor)

    1984-01-01

    A bandpass amplifier employing a field effect transistor amplifier first stage is described with a resistive load either a.c. or directly coupled to the non-inverting input of an operational amplifier second stage which is loaded in a Wien Bridge configuration. The bandpass amplifier may be operated with a signal injected into the gate terminal of the field effect transistor and the signal output taken from the output terminal of the operational amplifier. The operational amplifier stage appears as an inductive reactance, capacitive reactance and negative resistance at the non-inverting input of the operational amplifier, all of which appear in parallel with the resistive load of the field effect transistor.

  2. Cryogenic MMIC Low Noise Amplifiers

    NASA Technical Reports Server (NTRS)

    Weinreb, S.; Gaier, T.; Fernandez, J.; Erickson, N.; Wielgus, J.

    2000-01-01

    Monolithic (MMIC) and discrete transistor (MIC) low noise amplifiers are compared on the basis of performance, cost, and reliability. The need for cryogenic LNA's for future large microwave arrays for radio astronomy is briefly discussed and data is presented on a prototype LNA for the 1 to 10 GZH range along with a very wideband LNA for the 1 to 60 GHz range.

  3. Low-Noise Band-Pass Amplifier

    NASA Technical Reports Server (NTRS)

    Kleinberg, L.

    1982-01-01

    Circuit uses standard components to overcome common limitation of JFET amplifiers. Low-noise band-pass amplifier employs JFET and operational amplifier. High gain and band-pass characteristics are achieved with suitable choice of resistances and capacitances. Circuit should find use as low-noise amplifier, for example as first stage instrumentation systems.

  4. Cooled Low-Noise HEMT Microwave Amplifiers

    NASA Technical Reports Server (NTRS)

    Bautista, J. Javier; Ortiz, Gerardo G.; Duh, Kuanghann George

    1992-01-01

    Prototype cooled low-noise microwave amplifiers based on high-electron-mobility transistors (HEMT's) considered as replacements for cooled ruby masers used as low-noise receiver-front-end amplifiers in communications, radio science, radar systems, radio astronomy, and telemetry. HEMT amplifier operates at 12 K, requires less cooling power and operates at lower cost with simpler, more-reliable cooling system.

  5. Low-noise amplifiers for satellite communications

    NASA Astrophysics Data System (ADS)

    Whelehan, J.

    1984-02-01

    It is pointed out that over the past several years significant advances have been made in the overall capability of both microwave and mm-wave receivers. This is particularly apparent in the telecom market. Integral parts of advanced receiver technology are low-noise receivers. The advances currently being achieved in low-noise technology are partly based on developments in GaAs semiconductor technology. The development of high-cutoff-frequency beam lead mixer diodes has led to the development of mm-wave low-noise mixers with excellent low-noise capability. The advanced techniques are now being employed in field-deployable systems. Low noise is an important factor in satellite communications applications. Attention is given to C-band fixed satellite service, C-band parametric amplifiers, C-band FET, and X band, the Ku band, and the 30/20 GHz band.

  6. Ku band low noise parametric amplifier

    NASA Technical Reports Server (NTRS)

    1976-01-01

    A low noise, K sub u-band, parametric amplifier (paramp) was developed. The unit is a spacecraft-qualifiable, prototype, parametric amplifier for eventual application in the shuttle orbiter. The amplifier was required to have a noise temperature of less than 150 K. A noise temperature of less than 120 K at a gain level of 17 db was achieved. A 3-db bandwidth in excess of 350 MHz was attained, while deviation from phase linearity of about + or - 1 degree over 50 MHz was achieved. The paramp operates within specification over an ambient temperature range of -5 C to +50 C. The performance requirements and the operation of the K sub u-band parametric amplifier system are described. The final test results are also given.

  7. A Low-Noise Semiconductor Optical Amplifier

    SciTech Connect

    Ratowsky, R.P.; Dijaili, S.; Kallman, J.S.; Feit, M.D.; Walker, J.

    1999-03-23

    Optical amplifiers are essential devices for optical networks, optical systems, and computer communications. These amplifiers compensate for the inevitable optical loss in long-distance propagation (>50 km) or splitting (>10x). Fiber amplifiers such as the erbium-doped fiber amplifier have revolutionized the fiber-optics industry and are enjoying widespread use. Semiconductor optical amplifiers (SOAs) are an alternative technology that complements the fiber amplifiers in cost and performance. One obstacle to the widespread use of SOAs is the severity of the inevitable noise output resulting from amplified spontaneous emission (ASE). Spectral filtering is often used to reduce ASE noise, but this constrains the source spectrally, and improvement is typically limited to about 10 dB. The extra components also add cost and complexity to the final assembly. The goal of this project was to analyze, design, and take significant steps toward the realization of an innovative, low-noise SOA based on the concept of ''distributed spatial filtering'' (DSF). In DSF, we alternate active SOA segments with passive free-space diffraction regions. Since spontaneous emission radiates equally in all directions, the free-space region lengthens the amplifier for a given length of gain region, narrowing the solid angle into which the spontaneous emission is amplified [1,2]. Our innovation is to use spatial filtering in a differential manner across many segments, thereby enhancing the effect when wave-optical effects are included [3]. The structure quickly and effectively strips the ASE into the higher-order modes, quenching the ASE gain relative to the signal.

  8. Reflected-wave maser. [low noise amplifier

    NASA Technical Reports Server (NTRS)

    Clauss, R. C. (Inventor)

    1976-01-01

    A number of traveling-wave, slow-wave maser structures, containing active maser material but absent the typical ferrite isolators, are immersed in a nonuniform magnetic field. The microwave signal to be amplified is inserted at a circulator which directs the signal to a slow-wave structure. The signal travels through the slow-wave structure, being amplified according to the distance traveled. The end of the slow-wave structure farthest from the circulator is arranged to be a point of maximum reflection of the signal traveling through the slow-wave structure. As a consequence, the signal to be amplified traverses the slow-wave structure again, in the opposite direction (towards the circulator) experiencing amplification equivalent to that achieved by a conventional traveling-wave maser having twice the length. The circulator directs the amplified signal to following like stages of amplification. Isolators are used in between stages to prevent signals from traveling in the wrong direction, between the stages. Reduced signal loss is experienced at each stage. The high gain produced by each slow-wave structure is reduced to a moderate value by use of a nonuniform magnetic field which also broadens the line width of the maser material. The resulting bandwidth can be exceptionally wide. Cascaded stages provide high gain, exceptionally wide bandwith and very low noise temperature.

  9. 17 GHz low noise GaAs FET amplifier

    NASA Astrophysics Data System (ADS)

    Bharj, J. S.

    1984-10-01

    The considered amplifier is suitable for use as the first stage in a direct broadcast TV satellite receiver, and it was specifically designed for the Unisat spacecraft. Attention is given to RF device characterization, the design of the low-noise FET amplifier, the very significant dispersion effects at 17 GHz, the noise figure, and questions of DC bias. Balanced stages are used for low-noise and high-gain amplifiers to enhance the reliability. The noise figure of the amplifier is approximately 3.75 dB in the frequency band of interest. A low-noise microstrip GaAs FET amplifier circuit is shown.

  10. Matched wideband low-noise amplifiers for radio astronomy.

    PubMed

    Weinreb, S; Bardin, J; Mani, H; Jones, G

    2009-04-01

    Two packaged low noise amplifiers for the 0.3-4 GHz frequency range are described. The amplifiers can be operated at temperatures of 300-4 K and achieve noise temperatures in the 5 K range (<0.1 dB noise figure) at 15 K physical temperature. One amplifier utilizes commercially available, plastic-packaged SiGe transistors for first and second stages; the second amplifier is identical except it utilizes an experimental chip transistor as the first stage. Both amplifiers use resistive feedback to provide input reflection coefficient S11<-10 dB over a decade bandwidth with gain over 30 dB. The amplifiers can be used as rf amplifiers in very low noise radio astronomy systems or as i.f. amplifiers following superconducting mixers operating in the millimeter and submillimeter frequency range. PMID:19405681

  11. External Peltier Cooler For Low-Noise Amplifier

    NASA Technical Reports Server (NTRS)

    Soper, Terry A.

    1990-01-01

    Inexpensive Peltier-effect cooling module made of few commercially available parts used to reduce thermal noise in microwave amplifier. Retrofitted to almost any microwave low-noise amplifier or receiver preamplifier used in communication, telemetry, or radar. Includes copper or aluminum cold plate held tightly against unit to be cooled by strap-type worm-gear clamps.

  12. Tailoring HEMTs for low-noise amplifier designs

    NASA Astrophysics Data System (ADS)

    Jabra, A. A.; Smith, P. M.; Chao, P. C.; Baccarini, M.

    1988-10-01

    A Ku-band low-noise amplifier (LNA) for use in a multiple-access communication network such as that required by the Space Station is described. The unit uses high-electron-mobility transistors (HEMTs) to achieve 1.5-dB noise figure and 30-dB gain over its 13.4-13.8 GHz design bandwidth. HEMT technology is discussed as well as Ku-band amplifier design and amplifier performance.

  13. Cryogenic ultra-low-noise SiGe transistor amplifier.

    PubMed

    Ivanov, B I; Trgala, M; Grajcar, M; Il'ichev, E; Meyer, H-G

    2011-10-01

    An ultra-low-noise one-stage SiGe heterojunction bipolar transistor amplifier was designed for cryogenic temperatures and a frequency range of 10 kHz-100 MHz. A noise temperature T(N) ≈ 1.4 K was measured at an ambient temperature of 4.2 K at frequencies between 100 kHz and 100 MHz for a source resistance of ~50 Ω. The voltage gain of the amplifier was 25 dB at a power consumption of 720 μW. The input voltage noise spectral density of the amplifier is about 35 pV/√Hz. The low noise resistance and power consumption makes the amplifier suitable for readout of resistively shunted DC SQUID magnetometers and amplifiers. PMID:22047315

  14. A low-noise Peltier-cooled FET amplifier

    NASA Astrophysics Data System (ADS)

    Askew, R. E.; Wolkstein, H. J.

    1981-12-01

    A description is presented of a Peltier-cooled GaAs FET amplifier designed expressly to replace the complex and expensive parametric amplifier for satellite downlink receivers. The FET amplifier operates with an effective noise temperature (noise figure) at the terminal of less than 160 K (1.9 dB) and has an overall receiver gain of greater than 40 dB over the 7.25 to 7.75 GHz band. Attention is given to the developmental approach, aspects of electrical design, thermal considerations, packaging problems, the power supplies, and questions of cooler control. An investigation demonstrated the feasibility of replacing a parametric amplifier with a Peltier-cooled, low-noise FET amplifier for mast head operation in the 7.25-7.75 GHz band.

  15. X-Band Ultra-Low Noise Maser Amplifier Performance

    NASA Technical Reports Server (NTRS)

    Glass, G.; Johnson, D.; Ortiz, G.

    1993-01-01

    Noise temperature measurements of an 8440 MHz ultra-low noise maser amplifier (ULNA) have been performed at sub-atmospheric, liquid helium temperatures. The traveling wave maser operated while immersed in a liquid helium bath. The lowest input noise temperature measured was 1.23 plus or minus 0.16 K at a physical temperature of 1.60 kelvin. At this physical temperature the observed gain per unit length of ruby was 4.6 dB/cm, and the amplifier had a 3 dB-bandwidth of 76 MHz.

  16. Cross-talk free, low-noise optical amplifier

    DOEpatents

    Dijaili, S.P.; Patterson, F.G.; Deri, R.J.

    1995-07-25

    A low-noise optical amplifier solves crosstalk problems in optical amplifiers by using an optical cavity oriented off-axis (e.g. perpendicular) to the direction of a signal amplified by the gain medium of the optical amplifier. Several devices are used to suppress parasitic lasing of these types of structures. The parasitic lasing causes the gain of these structures to be practically unusable. The lasing cavity is operated above threshold and the gain of the laser is clamped to overcome the losses of the cavity. Any increase in pumping causes the lasing power to increase. The clamping action of the gain greatly reduces crosstalk due to gain saturation for the amplified signal beam. It also reduces other nonlinearities associated with the gain medium such as four-wave mixing induced crosstalk. This clamping action can occur for a bandwidth defined by the speed of the laser cavity. The lasing field also reduces the response time of the gain medium. By having the lasing field off-axis, no special coatings are needed. Other advantages are that the lasing field is easily separated from the amplified signal and the carrier grating fluctuations induced by four-wave mixing are decreased. Two related methods reduce the amplified spontaneous emission power without sacrificing the gain of the optical amplifier. 11 figs.

  17. Cross-talk free, low-noise optical amplifier

    DOEpatents

    Dijaili, Sol P.; Patterson, Frank G.; Deri, Robert J.

    1995-01-01

    A low-noise optical amplifier solves crosstalk problems in optical amplifiers by using an optical cavity oriented off-axis (e.g. perpendicular) to the direction of a signal amplified by the gain medium of the optical amplifier. Several devices are used to suppress parasitic lasing of these types of structures. The parasitic lasing causes the gain of these structures to be practically unusable. The lasing cavity is operated above threshold and the gain of the laser is clamped to overcome the losses of the cavity. Any increase in pumping causes the lasing power to increase. The clamping action of the gain greatly reduces crosstalk due to gain saturation for the amplified signal beam. It also reduces other nonlinearities associated with the gain medium such as four-wave mixing induced crosstalk. This clamping action can occur for a bandwidth defined by the speed of the laser cavity. The lasing field also reduces the response time of the gain medium. By having the lasing field off-axis, no special coatings are needed. Other advantages are that the lasing field is easily separated from the amplified signal and the carrier grating fluctuations induced by four-wave mixing are decreased. Two related methods reduce the amplified spontaneous emission power without sacrificing the gain of the optical amplifier.

  18. Low Noise Amplifiers and Receivers for Remote Sensing

    NASA Technical Reports Server (NTRS)

    Kangaslahti, Pekka; Lim, Boon; Gaier, Todd; Tanner, Alan; Varonen, Mikko; Samoska, Lorene; Brown, Shannon; Lambrigtsen, Bjorn; Reising, Steven; Tanabe, Jordan; Montes, Oliver; Dawson, Douglas; Parashare, Chaitali

    2011-01-01

    The study of atmospheric dynamics and climatology depend on accurate and frequent measurements of temperature and humidity profiles of the atmosphere. These measurements furthermore enable highly accurate measurements of ocean topography by providing total column water vapour data for radar path delay correction. The atmospheric temperature profile is characterised at the oxygen molecule absorption frequencies (60 and 118 GHz) and the humidity profile at the water molecule absorption frequencies (23 and 183 GHz). Total column measurements can be achieved by comparing measured radiometric temperatures at atmospheric window channels, such as 90, 130 and 166 GHz. The standard receiver technology for these frequencies was diode mixers with MMIC LNAs being applied at the lower frequencies. The sensitivity of millimetre wave receivers improved significantly with the introduction of the low noise 35 nm gate length InP MMIC amplifiers. We currently achieve 3 dB noise figure at 180 GHz and 2 dB noise figure at 90 GHz with our MMIC low noise amplifiers (LNAs) in room temperature. These amplifiers and the receivers we have built using them made it possible to conduct highly accurate airborne measurement campaigns from the Global Hawk unmanned aerial vehicle, develop millimeter wave internally calibrated radiometers for altimeter radar path delay correction, and build prototypes of large arrays of millimeter receivers for a geostationary interferometric sounder. We use the developed millimeter wave receivers to measure temperature and humidity profiles in the atmosphere and in hurricanes as well as to characterize the path delay error in ocean topography altimetry.

  19. Low Noise Amplifiers and Receivers for Remote Sensing

    NASA Technical Reports Server (NTRS)

    Kangaslahti, Pekka; Lim, Boon; Gaier, Todd; Tanner, Alan; Varonen, Mikko; Samoska, Lorene; Brown, Shannon; Lambrigsten, Bjorn; Reising, Steven; Tanabe, Jordan; Montes, Oliver; Dawson, Douglas; Parashare, Chaitali

    2012-01-01

    The study of atmospheric dynamics and climatology depend on accurate and frequent measurements of temperature and humidity profiles of the atmosphere. These measurements furthermore enable highly accurate measurements of ocean topography by providing total column water vapour data for radar path delay correction. The atmospheric temperature profile is characterized at the oxygen molecule absorption frequencies (60 and 118 GHz) and the humidity profile at the water molecule absorption frequencies (23 and 183 GHz). Total column measurements can be achieved by comparing measured radiometric temperatures at atmospheric window channels, such as 90, 130, and 166 GHz. The standard receiver technology for these frequencies was diode mixers with MMIC LNAs being applied at the lower frequencies. The sensitivity of millimeter wave receivers improved significantly with the introduction of the low noise 35 nm gate length InP MMIC amplifiers. We currently achieve 3 dB noise figure at 180 GHz and 2 dB noise figure at 90 GHz with our MMIC low noise amplifiers (LNAs) in room temperature. These amplifiers and the receivers we have built using them made it possible to conduct highly accurate airborne measurements campaigns from the Global Hawk unmanned aerial vehicle, develop millimeter wave internally calibrated radiometers for altimeter radar path delay correction, and build prototypes of large arrays of millimeter receivers for a geostationary interferometric sounder. We use the developed millimeter wave receivers to measure temperature and humidity profiles in the atmosphere and in hurricanes as well as to characterize the path delay error in ocean topography alitmetery.

  20. Low Noise Amplifier Receivers from Millimeter Wave Atmospheric Remote Sensing

    NASA Technical Reports Server (NTRS)

    Kangaslahti, Pekka; Lim, Boon; Gaier, Todd; Tanner, Alan; Varonen, Mikko; Samoska, Lorene; Brown, Shannon; Lambrigsten, Bjorn; Reising, Steven; Tanabe, Jordan; Montes, Oliver; Dawson, Douglas; Parashare, Chaitali

    2012-01-01

    We currently achieve 3.4 dB noise figure at 183GHz and 2.1 dB noise figure at 90 GHz with our MMIC low noise amplifiers (LNAs) in room temperature. These amplifiers and the receivers we have built using them made it possible to conduct highly accurate airborne measurement campaigns from the Global Hawk unmanned aerial vehicle, develop millimeter wave internally calibrated radiometers for altimeter radar path delay correction, and build prototypes of large arrays of millimeter receivers for a geostationary interferometric sounder. We use the developed millimeter wave receivers to measure temperature and humidity profiles in the atmosphere and in hurricanes as well as to characterize the path delay error in ocean topography altimetry.

  1. Thermal design of a thermoelectrically cooled low-noise amplifier

    NASA Astrophysics Data System (ADS)

    Hyman, N. L.; Hung, H.-L.

    1981-06-01

    The development of a thermoelectrically cooled low-noise amplifier is described in terms of thermal design concepts, optimization procedures, supporting analyses, and examples of measured performance. The design objectives achieved include a compact, low-cost small overall package size (19 x 19 x 28 cm) with a heat exchanger and fan capable of maintaining at room temperature ambient the preamplifier unit of an earth station low-noise amplifier at -90 C. The size of the unit measures 1.0 x 1.8 x 8.4 cm and has a heat dissipation of 150 mW. A low system component production cost was maintained, and a high reliability from a solid-state TEHP and a gas-filled hermetically sealed container guaranteed. An inexpensive and effective insulation system was developed, based on perlite powder-krypton gas and thermal shielding, and a flexible heat conductor for strain relief was built. It is concluded that the design principles are applicable to other electronic and optical components to maintain temperatures as low as -100 C.

  2. Low-Noise Amplifier for 100 to 180 GHz

    NASA Technical Reports Server (NTRS)

    Kangaslahti, Pekka; Pukala, David; Fung, King Man; Gaier, Todd; Mei, Xiaobing; Lai, Richard; Deal, William

    2009-01-01

    A three-stage monolithic millimeter-wave integrated-circuit (MMIC) amplifier designed to exhibit low noise in operation at frequencies from about 100 to somewhat above 180 GHz has been built and tested. This is a prototype of broadband amplifiers that have potential utility in diverse applications, including measurement of atmospheric temperature and humidity and millimeter-wave imaging for inspecting contents of opaque containers. Figure 1 depicts the amplifier as it appears before packaging. Figure 2 presents data from measurements of the performance of the amplifier as packaged in a WR-05 waveguide and tested in the frequency range from about 150 to about 190 GHz. The amplifier exhibited substantial gain throughout this frequency range. Especially notable is the fact that at 165 GHz, the noise figure was found to be 3.7 dB, and the noise temperature was found to be 370 K: This is less than half the noise temperature of the prior state of the art.

  3. Low-Noise MMIC Amplifiers for 120 to 180 GHz

    NASA Technical Reports Server (NTRS)

    Pukala, David; Samoska, Lorene; Peralta, Alejandro; Bayuk, Brian; Grundbacher, Ron; Oliver, Patricia; Cavus, Abdullah; Liu, Po-Hsin

    2009-01-01

    Three-stage monolithic millimeter-wave integrated-circuit (MMIC) amplifiers capable of providing useful amounts of gain over the frequency range from 120 to 180 GHz have been developed as prototype low-noise amplifiers (LNAs) to be incorporated into instruments for sensing cosmic microwave background radiation. There are also potential uses for such LNAs in electronic test equipment, passive millimeter- wave imaging systems, radar receivers, communication receivers, and systems for detecting hidden weapons. The main advantage afforded by these MMIC LNAs, relative to prior MMIC LNAs, is that their coverage of the 120-to-180-GHz frequency band makes them suitable for reuse in a wider variety of applications without need to redesign them. Each of these MMIC amplifiers includes InP transistors and coplanar waveguide circuitry on a 50- mthick chip (see Figure 1). Coplanar waveguide transmission lines are used for both applying DC bias and matching of input and output impedances of each transistor stage. Via holes are incorporated between top and bottom ground planes to suppress propagation of electromagnetic modes in the substrate. On the basis of computational simulations, each of these amplifiers was expected to operate with a small-signal gain of 14 dB and a noise figure of 4.3 dB. At the time of writing this article, measurements of noise figures had not been reported, but on-chip measurements had shown gains approaching their simulated values (see Figure 2).

  4. 160-190 GHz Monolithic Low Noise Amplifiers

    NASA Technical Reports Server (NTRS)

    Kok, Y. L.; Wang, H.; Huang, T. W.; Lai, R.; Chen, Y. C.; Sholley, M.; Block, T.; Streit, D. C.; Liu, P. H.; Allen, B. R.; Samoska, L.; Gaier, T.; Barsky, Mike

    1998-01-01

    This paper presents the results of two 160-190 GHz monolithic low noise amplifiers (LNAs) fabricated with 0.07-microns pseudomorphic (PM) InAlAs/InGaAs/InP HEMT technology using a reactive ion etch (RIE) via hole process. A peak small signal gain of 9 dB was measured at 188 GHz for the first LNA with a 3-dB bandwidth from 164 to 192 GHz while the second LNA has achieved over 6-dB gain from 142 to 180 GHz. The same design (second LNA) was also fabricated with 0.08-micron gate and a wet etch process, showing a small signal gain of 6 dB with noise figure 6 dB. All the measurement results were obtained via on-wafer probing. The LNA noise measurement at 170 GHz is also the first attempt at this frequency.

  5. Ultra-low noise miniaturized neural amplifier with hardware averaging

    NASA Astrophysics Data System (ADS)

    Dweiri, Yazan M.; Eggers, Thomas; McCallum, Grant; Durand, Dominique M.

    2015-08-01

    presence of high source impedances that are associated with the miniaturized contacts and the high channel count in electrode arrays. This technique can be adopted for other applications where miniaturized and implantable multichannel acquisition systems with ultra-low noise and low power are required.

  6. A Low Noise Amplifier for Neural Spike Recording Interfaces

    PubMed Central

    Ruiz-Amaya, Jesus; Rodriguez-Perez, Alberto; Delgado-Restituto, Manuel

    2015-01-01

    This paper presents a Low Noise Amplifier (LNA) for neural spike recording applications. The proposed topology, based on a capacitive feedback network using a two-stage OTA, efficiently solves the triple trade-off between power, area and noise. Additionally, this work introduces a novel transistor-level synthesis methodology for LNAs tailored for the minimization of their noise efficiency factor under area and noise constraints. The proposed LNA has been implemented in a 130 nm CMOS technology and occupies 0.053 mm-sq. Experimental results show that the LNA offers a noise efficiency factor of 2.16 and an input referred noise of 3.8 μVrms for 1.2 V power supply. It provides a gain of 46 dB over a nominal bandwidth of 192 Hz–7.4 kHz and consumes 1.92 μW. The performance of the proposed LNA has been validated through in vivo experiments with animal models. PMID:26437411

  7. A Low Noise Amplifier for Neural Spike Recording Interfaces.

    PubMed

    Ruiz-Amaya, Jesus; Rodriguez-Perez, Alberto; Delgado-Restituto, Manuel

    2015-01-01

    This paper presents a Low Noise Amplifier (LNA) for neural spike recording applications. The proposed topology, based on a capacitive feedback network using a two-stage OTA, efficiently solves the triple trade-off between power, area and noise. Additionally, this work introduces a novel transistor-level synthesis methodology for LNAs tailored for the minimization of their noise efficiency factor under area and noise constraints. The proposed LNA has been implemented in a 130 nm CMOS technology and occupies 0.053 mm-sq. Experimental results show that the LNA offers a noise efficiency factor of 2.16 and an input referred noise of 3.8 μVrms for 1.2 V power supply. It provides a gain of 46 dB over a nominal bandwidth of 192 Hz-7.4 kHz and consumes 1.92 μW. The performance of the proposed LNA has been validated through in vivo experiments with animal models. PMID:26437411

  8. Cryogenic ultra-low noise HEMT amplifiers board

    NASA Astrophysics Data System (ADS)

    de la Broïse, Xavier; Bounab, Ayoub

    2015-07-01

    High Electron Mobility Transistors (HEMTs), optimized by CNRS/LPN laboratory for ultra-low noise at a very low temperature, have demonstrated their capacity to be used in place of Si JFETs, when very high input impedance and working temperatures below 100 K are required. We have developed and tested simple amplifiers based only on this transistor technology, in order to work at a temperature as low as 1 K or less. They demonstrate at 4.2 K a typical noise of 1.6 nV/√{ Hz } at 100 Hz, 0.42 nV/√{ Hz } at 1 kHz and 0.32 nV/√{ Hz } at 10 kHz, with a gain of 50 and a power consumption of 1.4 mW per channel. Two boards have been designed for two different research applications: one for the readout of GMR magnetometers for medical and space applications, the other for search of weakly interacting massive particles (WIMPs) in Edelweiss experiment (HARD project).

  9. A low-noise 4.8 GHz amplifier for the Russian Radioastron VLBI satellite

    NASA Astrophysics Data System (ADS)

    Schmidt, A.; Wongsowijoto, Sam

    A low-noise 4.8 GHz amplifier has been designed for the Russian Radioastron satellite. The design, realization, and spaceflight testing of the amplifier are briefly described. The most important parameters of the prototype are given.

  10. A 2385 MHz, 2-stage low noise amplifier design

    NASA Technical Reports Server (NTRS)

    Sifri, Jack D.

    1986-01-01

    This article shows the design aspects of a 2.385 GHz low noise preamplifier with a .7 dB noise figure and 16.5 dB gain using the NE 67383 FET. The design uses a unique method in matching the input which achieves optimum noise figure and unconditional stability.

  11. W-band InP based HEMT MMIC low noise amplifiers

    NASA Technical Reports Server (NTRS)

    Lin, K. Y.; Tang, Y. L.; Wang, H.; Gaier, T.; Gough, R. G.; Sinclair, M.

    2002-01-01

    This paper presents the designs and measurement results of a three-stage and a four-stage W-band monolithic microwave integrated circuits (MMIC) including a three-stage and a four-stage low noise amplifiers.

  12. Matching technique yields optimum LNA performance. [Low Noise Amplifiers

    NASA Technical Reports Server (NTRS)

    Sifri, J. D.

    1986-01-01

    The present article is concerned with a case in which an optimum noise figure and unconditional stability have been designed into a 2.385-GHz low-noise preamplifier via an unusual method for matching the input with a suspended line. The results obtained with several conventional line-matching techniques were not satisfactory. Attention is given to the minimization of thermal noise, the design procedure, requirements for a high-impedance line, a sampling of four matching networks, the noise figure of the single-line matching network as a function of frequency, and the approaches used to achieve unconditional stability.

  13. Thirty GHz low noise GaAs FET amplifiers

    NASA Astrophysics Data System (ADS)

    Oxley, C. H.; Arnold, J.

    1984-09-01

    Selection and characterization of transmission media, and characterization of a 0.3 micron gate length gallium arsenide MESFET usable to 30 GHz, was undertaken to provide a data base for the design of an integrated amplifier for satellite communications. An amplifier configuration was chosen to achieve the ESA specification, and single stage amplifier modules were designed and tested. Integration of these modules into a complete high gain amplifier with temperature compensation and operating between WG22 interfaces is achieved. Tests against the full performance specification were conducted.

  14. 32-GHz cryogenically cooled HEMT low-noise amplifiers

    NASA Technical Reports Server (NTRS)

    Duh, K. H. George; Kopp, William F.; Ho, Pin; Chao, Pane-Chane; Ko, Ming-Yih; Smith, Phillip M.; Ballingall, James M.; Bautista, J. Javier; Ortiz, Gerardo G.

    1989-01-01

    The cryogenic noise temperature performance of a two-stage and a three-stage 32 GHz high electron mobility transistor (HEMT) amplifier was evaluated. The amplifiers employ 0.25 micrometer conventional AlGaAs/GaAs HEMT devices, hybrid matching input and output microstrip circuits, and a cryogenically stable dc biasing network. The noise temperature measurements were performed in the frequency range of 31 to 33 GHz over a physical temperature range of 300 K down to 12 K. Across the measurement band, the amplifiers displayed a broadband response, and the noise temperature was observed to decrease by a factor of 10 in cooling from 300 to 15 K. The lowest noise temperature measured for the two-stage amplifier at 32 GHz was 35 K with an associated gain of 16.5 dB, while the three-stage amplifier measured 39 K with an associated gain of 26 dB. It was further observed that both amplifiers were insensitive to light.

  15. On 32-GHz cryogenically cooled HEMT low-noise amplifiers

    NASA Technical Reports Server (NTRS)

    Bautista, J. J.; Ortiz, G. G.; Duh, K. H. G.; Kopp, W. F.; Ho, P.; Chao, P. C.; Kao, M. Y.; Smith, P. M.; Ballingall, J. M.

    1988-01-01

    The cryogenic noise temperature performance of a two-stage and a three-stage 32 GHz High Electron Mobility Transistor (HEMT) amplifier was evaluated. The amplifiers employ 0.25 micrometer conventional AlGaAs/GaAs HEMT devices, hybrid matching input and output microstrip circuits, and a cryogenically stable dc biasing network. The noise temperature measurements were performed in the frequency range of 31 to 33 GHz over a physical temperature range of 300 K down to 12 K. Across the measurement band, the amplifiers displayed a broadband response, and the noise temperature was observed to decrease by a factor of 10 in cooling from 300 K to 15 K. The lowest noise temperature measured for the two-stage amplifier at 32 GHz was 35 K with an associated gain of 16.5 dB, while the three-stage amplifier measured 39 K with an associated gain of 26 dB. It was further observed that both amplifiers were insensitive to light.

  16. Superconducting Quantum Arrays for Wideband Antennas and Low Noise Amplifiers

    NASA Technical Reports Server (NTRS)

    Mukhanov, O.; Prokopemko, G.; Romanofsky, Robert R.

    2014-01-01

    Superconducting Quantum Iinetference Filters (SQIF) consist of a two-dimensional array of niobium Josephson Junctions formed into N loops of incommensurate area. This structure forms a magnetic field (B) to voltage transducer with an impulse like response at B0. In principle, the signal-to-noise ratio scales as the square root of N and the noise can be made arbitrarily small (i.e. The SQIF chips are expected to exhibit quantum limited noise performance). A gain of about 20 dB was recently demonstrated at 10 GHz.

  17. Burnout studies of X-band radar negative resistance transistor low noise amplifiers

    NASA Astrophysics Data System (ADS)

    Paul, D. K.; Gardner, P.

    1992-03-01

    GaAs FETs and HEMTs can be configured to give low noise, negative resistance microwave amplification. Such low noise amplifiers have the advantage of an inherent bypass path after device burnout. This feature is potentially useful in radar receiver applications. Test results for prototype LNAs are described, showing burnout energies comparable to those of conventional transmission mode amplifiers using similar devices. Bypass path losses after burnout are around 4 dB, approximately 20 dB less than for a failed transmission mode amplifier.

  18. Problems of the design of low-noise input devices. [parametric amplifiers

    NASA Technical Reports Server (NTRS)

    Manokhin, V. M.; Nemlikher, Y. A.; Strukov, I. A.; Sharfov, Y. A.

    1974-01-01

    An analysis is given of the requirements placed on the elements of parametric centimeter waveband amplifiers for achievement of minimal noise temperatures. A low-noise semiconductor parametric amplifier using germanium parametric diodes for a receiver operating in the 4 GHz band was developed and tested confirming the possibility of satisfying all requirements.

  19. Two-Stage, 90-GHz, Low-Noise Amplifier

    NASA Technical Reports Server (NTRS)

    Samoska, Lorene A.; Gaier, Todd C.; Xenos, Stephanie; Soria, Mary M.; Kangaslahti, Pekka P.; Cleary, Kieran A.; Ferreira, Linda; Lai, Richard; Mei, Xiaobing

    2010-01-01

    A device has been developed for coherent detection of the polarization of the cosmic microwave background (CMB). A two-stage amplifier has been designed that covers 75-110 GHz. The device uses the emerging 35-nm InP HEMT technology recently developed at Northrop Grumman Corporation primarily for use at higher frequencies. The amplifier has more than 18 dB gain and less than 35 K noise figure across the band. These devices have noise less than 30 K at 100 GHz. The development started with design activities at JPL, as well as characterization of multichip modules using existing InP. Following processing, a test campaign was carried out using single-chip modules at 100 GHz. Successful development of the chips will lead to development of multichip modules, with simultaneous Q and U Stokes parameter detection. This MMIC (monolithic microwave integrated circuit) amplifier takes advantage of performance improvements intended for higher frequencies, but in this innovation are applied at 90 GHz. The large amount of available gain ultimately leads to lower possible noise performance at 90 GHz.

  20. Miniature Ku-band low-noise amplifier using batch-process technology

    NASA Astrophysics Data System (ADS)

    Fathy, A.; Jozwiak, P.; Mykietyn, E.; Pendrick, V.; Brown, R.

    1986-12-01

    The steps in developing a low-noise three-stage miniature amplifier operating from 11.7 to 12.2 GHz are examined. The amplifier has an 18-dB gain over the band and a noise figure of 4 dB. An accurate network model, including a feedback loop, is presented for the design and optimization of the amplifier. The circuit realization and the measured performance in relation to VSWR, gain flatness, stability, and noise figure, are discussed.

  1. A 20-GHz low-noise HEMT amplifier for satellite communications

    NASA Astrophysics Data System (ADS)

    Tokumitsu, Y.; Niori, M.; Saito, T.

    1984-03-01

    A description is given of a 20-Ghz low-noise amplifier that uses a new device, a low-noise high electron mobiity transistor (HEMT), developed for the receiver front-end in earth stations for 30/20-GHz satellite communications systems. The minimum noise figure of the HEMT is 3.1 dB, and the associated gain is 7.5 dB at 20 GHz. It is believed that before too long the HEMT will surpass the GaAs FET as a low-noise device. In the test amplifier at an operating frequency range from 17.6 GHz to 19.2 Ghz, the noise figure is 4.2 dB and the gain is 28.6 dB. The minimum noise figure is 3.9 dB. It is expected that cooling the amplifier will give a significant improvement in the noise figure.

  2. Cryogenic Design of the Deep Space Network Large Array Low-Noise Amplifier System

    NASA Astrophysics Data System (ADS)

    Britcliffe, M. J.; Hanson, T. R.; Franco, M. M.

    2004-05-01

    This article describes the cryogenic design and performance of a prototype low-noise amplifier (LNA) system for the Deep Space Network (DSN) Large Array task. The system is used to cool a dual-frequency feed system equipped with high-electron mobility transistor (HEMT) low-noise amplifiers and the associated support electronics. The LNA/feed system operates at a temperature under 18 K. The system is designed to be manufactured at minimum cost. The design considerations, including the cryocooler to be used, vacuum system, microwave interconnects, mechanical components, and radiation shielding, are discussed.

  3. A Ka-band Four-stage Self-biased Monolithic Low Noise Amplifier

    NASA Astrophysics Data System (ADS)

    Yang, Ziqiang; Yang, Tao; Liu, Yu

    2009-05-01

    A Ka-band four-stage self-biased monolithic low noise amplifier has been developed using a commercial 0.18-µm pseudomorphic high electron-mobility transistor (pHEMT) process. For the application of self-bias technique, the low noise amplifier (LNA) is biased from a single power supply rail. The LNA has achieved a broadband performance with a gain of more than 18 dB, a noise figure of less than 3.8 dB in the RF frequency of 26 to 40 GHz. The chip size is 3 × 1 mm2.

  4. Cryogenic, low-noise high electron mobility transistor amplifiers for the Deep Space Network

    NASA Technical Reports Server (NTRS)

    Bautista, J. J.

    1993-01-01

    The rapid advances recently achieved by cryogenically cooled high electron mobility transistor (HEMT) low-noise amplifiers (LNA's) in the 1- to 10-GHz range are making them extremely competitive with maser amplifiers. In order to address future spacecraft navigation, telemetry, radar, and radio science needs, the Deep Space Network is investing both maser and HEMT amplifiers for its Ka-band (32-GHz) downlink capability. This article describes the current state cryogenic HEMT LNA development at Ka-band for the DSN. Noise performance results at S-band (2.3 GHz) and X-band (8.5 GHz) for HEMT's and masers are included for completeness.

  5. Cryogenic, low-noise high electron mobility transistor amplifiers for the Deep Space Network

    NASA Astrophysics Data System (ADS)

    Bautista, J. J.

    1993-11-01

    The rapid advances recently achieved by cryogenically cooled high electron mobility transistor (HEMT) low-noise amplifiers (LNA's) in the 1- to 10-GHz range are making them extremely competitive with maser amplifiers. In order to address future spacecraft navigation, telemetry, radar, and radio science needs, the Deep Space Network is investing both maser and HEMT amplifiers for its Ka-band (32-GHz) downlink capability. This article describes the current state cryogenic HEMT LNA development at Ka-band for the DSN. Noise performance results at S-band (2.3 GHz) and X-band (8.5 GHz) for HEMT's and masers are included for completeness.

  6. GaAs FET MMIC low-noise amplifiers for satellite communications

    NASA Astrophysics Data System (ADS)

    Hung, H.-L.; Enobakhare, E.; Abita, J.; McNally, P.; Mahle, C.

    1985-12-01

    One- and two-stage, X-band, low-noise, GaAs FET monolithic amplifier modules have been developed. These amplifier chips include all dc-blocking capacitors and bias networks. A cascaded, two-chip, two-stage amplifier module provides a noise figure of 4 dB and an associated gain of 30 dB from 9.5 to 11.7 GHz. A two-stage 15-dB gain block has also been developed for 9 to 13 GHz, with a chip size of 1.7 x 1.2 mm.

  7. Low Noise Amplifiers for 140 Ghz Wide-Band Cryogenic Receivers

    NASA Technical Reports Server (NTRS)

    Larkoski, Patricia V.; Kangaslahti, Pekka; Samoska, Lorene; Lai, Richard; Sarkozy, Stephen

    2013-01-01

    We report S-parameter and noise measurements for three different Indium Phosphide 35-nanometer-gate-length High Electron Mobility Transistor (HEMT) Low Noise Amplifier (LNA) designs operating in the frequency range centered on 140 gigahertz. When packaged in a Waveguide Rectangular-6.1 waveguide housing, the LNAs have an average measured noise figure of 3.0 decibels - 3.6 decibels over the 122-170 gigahertz band. One LNA was cooled to 20 degrees Kelvin and a record low noise temperature of 46 Kelvin, or 0.64 decibels noise figure, was measured at 152 gigahertz. These amplifiers can be used to develop receivers for instruments that operate in the 130-170 gigahertz atmospheric window, which is an important frequency band for ground-based astronomy and millimeter-wave imaging applications.

  8. Low noise buffer amplifiers and buffered phase comparators for precise time and frequency measurement and distribution

    NASA Technical Reports Server (NTRS)

    Eichinger, R. A.; Dachel, P.; Miller, W. H.; Ingold, J. S.

    1982-01-01

    Extremely low noise, high performance, wideband buffer amplifiers and buffered phase comparators were developed. These buffer amplifiers are designed to distribute reference frequencies from 30 KHz to 45 MHz from a hydrogen maser without degrading the hydrogen maser's performance. The buffered phase comparators are designed to intercompare the phase of state of the art hydrogen masers without adding any significant measurement system noise. These devices have a 27 femtosecond phase stability floor and are stable to better than one picosecond for long periods of time. Their temperature coefficient is less than one picosecond per degree C, and they have shown virtually no voltage coefficients.

  9. A Low-Noise Transimpedance Amplifier for BLM-Based Ion Channel Recording

    PubMed Central

    Crescentini, Marco; Bennati, Marco; Saha, Shimul Chandra; Ivica, Josip; de Planque, Maurits; Morgan, Hywel; Tartagni, Marco

    2016-01-01

    High-throughput screening (HTS) using ion channel recording is a powerful drug discovery technique in pharmacology. Ion channel recording with planar bilayer lipid membranes (BLM) is scalable and has very high sensitivity. A HTS system based on BLM ion channel recording faces three main challenges: (i) design of scalable microfluidic devices; (ii) design of compact ultra-low-noise transimpedance amplifiers able to detect currents in the pA range with bandwidth >10 kHz; (iii) design of compact, robust and scalable systems that integrate these two elements. This paper presents a low-noise transimpedance amplifier with integrated A/D conversion realized in CMOS 0.35 μm technology. The CMOS amplifier acquires currents in the range ±200 pA and ±20 nA, with 100 kHz bandwidth while dissipating 41 mW. An integrated digital offset compensation loop balances any voltage offsets from Ag/AgCl electrodes. The measured open-input input-referred noise current is as low as 4 fA/√Hz at ±200 pA range. The current amplifier is embedded in an integrated platform, together with a microfluidic device, for current recording from ion channels. Gramicidin-A, α-haemolysin and KcsA potassium channels have been used to prove both the platform and the current-to-digital converter. PMID:27213382

  10. A Low-Noise Transimpedance Amplifier for BLM-Based Ion Channel Recording.

    PubMed

    Crescentini, Marco; Bennati, Marco; Saha, Shimul Chandra; Ivica, Josip; de Planque, Maurits; Morgan, Hywel; Tartagni, Marco

    2016-01-01

    High-throughput screening (HTS) using ion channel recording is a powerful drug discovery technique in pharmacology. Ion channel recording with planar bilayer lipid membranes (BLM) is scalable and has very high sensitivity. A HTS system based on BLM ion channel recording faces three main challenges: (i) design of scalable microfluidic devices; (ii) design of compact ultra-low-noise transimpedance amplifiers able to detect currents in the pA range with bandwidth >10 kHz; (iii) design of compact, robust and scalable systems that integrate these two elements. This paper presents a low-noise transimpedance amplifier with integrated A/D conversion realized in CMOS 0.35 μm technology. The CMOS amplifier acquires currents in the range ±200 pA and ±20 nA, with 100 kHz bandwidth while dissipating 41 mW. An integrated digital offset compensation loop balances any voltage offsets from Ag/AgCl electrodes. The measured open-input input-referred noise current is as low as 4 fA/√Hz at ±200 pA range. The current amplifier is embedded in an integrated platform, together with a microfluidic device, for current recording from ion channels. Gramicidin-A, α-haemolysin and KcsA potassium channels have been used to prove both the platform and the current-to-digital converter. PMID:27213382

  11. A Dynamic Instrumentation Amplifier for Low-Power and Low-Noise Biopotential Acquisition

    PubMed Central

    Kim, Jongpal; Ko, Hyoungho

    2016-01-01

    A low-power and low-noise dynamic instrumentation amplifier (IA) for biopotential acquisition is presented. A dynamic IA that can reduce power consumption with a timely piecewise power-gating method, and noise level with an alternating input and chopper stabilization technique is fabricated with a 0.13-μm CMOS. Using the reconfigurable architecture of the IA, various combinations of the low-noise schemes are investigated. The combination of power gating and chopper stabilization shows a lower noise performance than the combination of power gating and alternating input switching scheme. This dynamic IA achieved a power reduction level of 50% from 10 µA to 5 µA and a noise reduction of 90% from 9.1 µVrms to 0.92 µVrms with the combination of the power gating and chopper stabilization scheme.

  12. A microwave cryogenic low-noise amplifier based on sige heterostructures

    NASA Astrophysics Data System (ADS)

    Ivanov, B. I.; Grajcar, M.; Novikov, I. L.; Vostretsov, A. G.; Il'ichev, E.

    2016-04-01

    A low-noise cryogenic amplifier for the measurement of weak microwave signals at sub-Kelvin temperatures is constructed. The amplifier has five stages based on SiGe bipolar heterostructure transistors and has a gain factor of 35 dB in the frequency band from 100 MHz to 4 GHz at an operating temperature of 800 mK. The parameters of a superconducting quantum bit measured with this amplifier in the ultralow-power mode are presented as an application example. The amplitude-frequency response of the "supercon-ducting qubit-coplanar cavity" structure is demonstrated. The ground state of the qubit is characterized in the quasi-dispersive measurement mode.

  13. Using the SLUG as a First Stage, Low Noise Microwave Amplifier for Superconducting Qubit Readout

    NASA Astrophysics Data System (ADS)

    Leonard, Edward, Jr.; Thorbeck, Ted; Zhu, Shaojiang; McDermott, Robert

    2015-03-01

    The SLUG (Superconducting Low-inductance Undulatory Galvonometer) microwave amplifier is a large bandwidth, high saturation power, high gain, and low noise microwave element designed as a first stage cryogenic amplifier for dispersive readout of superconducting qubits. High forward gain is paired with simultaneous high reverse isolation such that bulky, expensive cryogenic circulators and isolators might be eliminated from the microwave readout chain. Here we present recent experimental data on SLUG gain, noise, and reverse isolation. We achieve gain over 10 dB at 7 GHz across a band of several hundred MHz, with system added noise of order one photon. For appropriate flux bias of the device, reverse isolation is better than -20 dB. These qualities make the SLUG a very desirable first stage amplifier for a scalable superconducting qubit readout.

  14. High-performance Ka-band and V-band HEMT low-noise amplifiers

    NASA Technical Reports Server (NTRS)

    Duh, K. H. George; Chao, Pane-Chane; Smith, Phillip M.; Lester, Luke F.; Lee, Benjamin R.

    1988-01-01

    Quarter-micron-gate-length high-electron-mobility transistors (HEMTs) have exhibited state-of-the-art low-noise performance at millimeter-wave frequencies, with minimum noise figures of 1.2 dB at 32 GHz and 1.8 dB at 60 GHz. At Ka-band, two-stage and three-stage HEMT low noise amplifiers have demonstrated noise figures of 1.7 and 1.9 dB, respectively, with associated gains of 17.0 and 24.0 dB at 32 GHz. At V-band, two stage and three-stage HEMT amplifiers yielded noise figures of 3.2 and 3.6 dB, respectively, with associated gains of 12.7 and 20.0 dB at 60 GHz. The 1-dB-gain compression point of all the amplifiers is greater than +6 dBm. The results clearly show the potential of short-gate-length HEMTs for high-performance millimeter-wave receiver applications.

  15. A 2.3-GHz low-noise cryo-FET amplifier

    NASA Technical Reports Server (NTRS)

    Loreman, J.

    1988-01-01

    A cryogenic cooled, low-noise Field Effect Transistor (FET) amplifier assembly for use at 2.2 to 2.3 GHz was developed for the DSN to meet the requirements of a Very Long Baseline Interferometry (VLBI) upgrade. An amplifier assembly was developed at JPL that uses a commercial closed-cycle helium refrigerator (CCR) to cool a FET amplifier to an operating temperature of 15 K. A cooled probe waveguide-to-coaxial transition similar to that used in the research and development Ultra-Low-Noise S-band Traveling Wave Maser (TWM) is used to minimize input line losses. Typical performance includes an input flange equivalent noise contribution of 14.5 K, a gain slope of less than 0.05 dB/MHz across a bandwidth of 2.2 to 2.3 GHz, an input VSWR of 1.5:1 at 2.25 GHz, and an insertion gain of 45 + or - 1 dB across the bandwidth of 2.2 to 2.3 GHz. Three 2.3 GHz FET/CCR assemblies were delivered to the DSN in the spring of 1987.

  16. Tests of Low-Noise MMIC Amplifier Module at 290 to 340 GHz

    NASA Technical Reports Server (NTRS)

    Gaier, Todd; Samoska, Lorene; Fung, King Man; Deal, William; Mei, Xiaobing; Lai, Richard

    2009-01-01

    A document presents data from tests of a low-noise amplifier module operating in the frequency range from 290 to 340 GHz said to be the highest-frequency low-noise, solid-state amplifier ever developed. The module comprised a three-stage monolithic microwave integrated circuit (MMIC) amplifier integrated with radial probe MMIC/waveguide transitions and contained in a compact waveguide package, all according to the concepts described in the immediately preceding article and in the referenced prior article, "Integrated Radial Probe Transition From MMIC to Waveguide" (NPO-43957), NASA Tech Briefs Vol. 31, No. 5 (May 2007), page 38. The tests included measurements by the Y-factor method, in which noise figures are measured repeatedly with an input noise source alternating between an "on" (hot-load) condition and an "off" (cold-load) condition. (The Y factor is defined as the ratio between the "on" and "off" noise power levels.) The test results showed that, among other things, the module exhibited a minimum noise figure of about 8.7 dB at 325 GHz and that the gain at that frequency under the bias conditions that produced the minimum noise figure was between about 9 and 10 dB.

  17. Development of a cryogenic DC-low noise amplifier for SQuID-based readout electronics

    NASA Astrophysics Data System (ADS)

    Macculi, C.; Torrioli, G.; Di Giorgio, A.; Spinoglio, L.; Piro, Luigi

    2014-07-01

    We present the preliminary results of the design and test activities for a DC cryogenic low noise amplifier for the SAFARI imaging spectrometer, planned to be onboard the SPICA mission, necessary not only to drive, as usual, the voltage signal produced by the SQuID but also to boost such signals over about 7 meter of path towards the warm feedback electronics. This development has been done in the framework of the mission preparation studies, within the European Consortium for the development of the SAFARI instrument. The actual configuration of the SAFARI focal plane assembly (FPA), indeed, foresees a long distance to the warm back end electronics. It is therefore mandatory to boost the faint electric signal coming from the SQuID device by keeping under control both power dissipation and noise: this is the main role of the designed Cryogenic Low Noise Amplifier (LNA). Working at 136K, it has a differential input gain-stage, and a differential balanced voltage buffer output stage, running at few mW target overall power. At present the design is based on the use of Heterojunction Si:Ge transistors, the required bandwidth is DC-4MHz and the required noise lower than 1 nV/rtHz.

  18. 50 W low noise dual-frequency laser fiber power amplifier.

    PubMed

    Kang, Ying; Cheng, Lijun; Yang, Suhui; Zhao, Changming; Zhang, Haiyang; He, Tao

    2016-05-01

    A three-stage dual-frequency laser signal amplification system is presented. An output from a narrow-linewidth Nd:YAG nonplanar ring-oscillator (NPRO) is split into two parts, one of them is frequency shifted by an acoustooptic modulator (AOM) then coupled into a single mode optical fiber. The other part is coupled into another single mode fiber then combined with the frequency-shifted beam with a 2 to 1 single mode fiber coupler. The combined beam has a power of 20 mW containing two frequency components with frequency separation of 150 ± 25 MHz. The dual-frequency signal is amplified via a three-stage Yb3+-doped diode pumped fiber power amplifier. The maximum amplified power is 50.3 W corresponding to a slope efficiency of 73.72% of the last stage. The modulation depth and signal to noise ratio (SNR) of the beat signal are well maintained in the amplifying process. The dual-frequency laser fiber power amplifier provides robust optical carried RF signal with high power and low noise. PMID:27137536

  19. Updated design for a low-noise, wideband transimpedance photodiode amplifier

    SciTech Connect

    Paul, S. F.; Marsala, R.

    2006-10-15

    The high-speed rotation diagnostic developed for Columbia's HBT-EP tokamak requires a high quantum efficiency, very low drift detector/amplifier combination. An updated version of the circuit developed originally for the beam emission spectroscopy experiment on TFTR is being used. A low dark current (2 nA at 15 V bias), low input source capacitance (2 pF) FFD-040 N-type Si photodiode is operated in photoconductive mode. It has a quantum efficiency of 40% at the 468.6 nm (He II line that is being observed). A low-noise field-effect transistor (InterFET IFN152 with e{sub Na}=1.2 nV/{radical}Hz) is used to reduce the noise in the transimpedance preamplifier (A250 AMPTEK op-amp) and a very high speed (unity-gain bandwidth=200 MHz) voltage feedback amplifier (LM7171) is used to restore the frequency response up to 100 kHz. This type of detector/amplifier is photon-noise limited at this bandwidth for incident light with a power of >{approx}2 nW. The circuit has been optimized using SIMETRIX 4.0 SPICE software and a prototype circuit has been tested successfully. Though photomultipliers and avalanche photodiodes can detect much lower light levels, for light levels >2 nW and a 10 kHz bandwidth, this detector/amplifier combination is more sensitive because of the absence of excess (internally generated) noise.

  20. Validation of the ultrastable low-noise current amplifier as travelling standard for small direct currents

    NASA Astrophysics Data System (ADS)

    Drung, D.; Krause, C.; Giblin, S. P.; Djordjevic, S.; Piquemal, F.; Séron, O.; Rengnez, F.; Götz, M.; Pesel, E.; Scherer, H.

    2015-12-01

    An interlaboratory comparison of small-current generation and measurement capability is presented with the ultrastable low-noise current amplifier (ULCA) acting as travelling standard. Various measurements at direct currents between 0.16 nA and 13 nA were performed to verify the degree of agreement between the three national metrology institutes involved in the study. Consistency well within one part per million (ppm) was found. Due to harsh environmental conditions during shipment, the ULCA’s transfer accuracy had been limited to about  ±0.4 ppm. Supplemental measurements performed at PTB indicate that further improvements in accuracy are possible. Relative uncertainties of 0.1 ppm are achieved by applying on-site calibration of the ULCA with a suitable cryogenic current comparator.

  1. Wideband ultra-low noise cryogenic InP IF amplifiers for the Herschel mission radiometers

    NASA Astrophysics Data System (ADS)

    Lopez-Fernandez, Isaac; Gallego-Puyol, Juan D.; Diez, Carmen; Barcia, Alberto; Martin-Pintado, Jesus

    2003-02-01

    The sub-millimeter radiometers of the Herschel mission have very stringent requirements. The scientific goals require an instantaneous bandwidth of four GHz with very low noise, flat gain and low power dissipation. Short-term gain stability of the amplifier is important, because gain fluctuations could limit the sensitivity of the instrument. Besides, a highly reliable, low weight unit is required to be compatible with the space instrumentation standards. The amplifiers will be used in conjunction with HEB and SIS mixers in all 7 channels of the instrument. This paper describes the design, the special construction techniques and the results of the amplifiers built by Centro Astronómico de Yebes for the development model of the Herschel Heterodyne Instrument. The average noise temperature obtained in the 4-8 GHz band is 3.5 K, with a gain of 27 +/-1.1 dB at an ambient temperature of 15 K and keeping the total power dissipation below the allowed 4 mW. Normalized gain fluctuations were carefully measured, being lower than 1.5·10-4 Hz-1/2 @ 1 Hz. Space qualification of the design is in progress.

  2. Instrumental and Observational Studies in Radio Astronomy, Low Noise Amplifier Design and Methanol Maser Research

    NASA Astrophysics Data System (ADS)

    Minier, V.

    1998-10-01

    ``Radio astronomy is the study of the universe by observing electromagnetic radiation after it has been amplified. The use of amplifiers that preserve the oscillatory character of radiation - the phase information - is the mark of Radio astronomy.'' Thus, the development of low noise amplifiers for microwave and millimeter wavelengths is a major part of Radio astronomy as important as the observations themselves. This technical report involves those two aspects of Radio astronomy, the observational and technical aspects. In the first part, observations of methanol masers in massive star forming regions using Very Long Baseline Interferometry (VLBI) are presented. The second part concerns the realization of low noise amplifiers using in a radio camera. Recent observations have confirmed that the methanol masers are powerful tools for probing the regions of massive star formation. The methanol masers fall in two distinct classes related to their location in the star forming regions. Class I methanol masers are observed offset far away from the UC HII region emission peak. They are certainly collisionally pumped and may occur in the interface between high velocity gas outflows and the ambient molecular material. Class II methanol masers coincide with the UC HII region emission. They may be radiatively pumped by FIR radiation from the dust grains and reside either in spherical layers surrounding the UC HII regions or in circumstellar discs. The maser spots are usually compact (~1-10 AU) and lie in region of physical conditions n(H)~104-108 cm-3 and T=100-1000 K. CH3OH may be produced by hydrogenation of CO on the surface of the icy mantles of the dust grains . The methanol is then injected in the molecular gas by evaporation of the ice (n(H)=106 cm-3, T=100-300 K). In this report we present VLBI observations of 6.7 and 12.2 GHz methanol masers in the star forming regions NGC7538, W75N and S252. Our results show the existence of two groups of masers in NGC7538. The

  3. Simple nonlinearity evaluation and modeling of low-noise amplifiers with application to radio astronomy receivers.

    PubMed

    Casas, F J; Pascual, J P; de la Fuente, M L; Artal, E; Portilla, J

    2010-07-01

    This paper describes a comparative nonlinear analysis of low-noise amplifiers (LNAs) under different stimuli for use in astronomical applications. Wide-band Gaussian-noise input signals, together with the high values of gain required, make that figures of merit, such as the 1 dB compression (1 dBc) point of amplifiers, become crucial in the design process of radiometric receivers in order to guarantee the linearity in their nominal operation. The typical method to obtain the 1 dBc point is by using single-tone excitation signals to get the nonlinear amplitude to amplitude (AM-AM) characteristic but, as will be shown in the paper, in radiometers, the nature of the wide-band Gaussian-noise excitation signals makes the amplifiers present higher nonlinearity than when using single tone excitation signals. Therefore, in order to analyze the suitability of the LNA's nominal operation, the 1 dBc point has to be obtained, but using realistic excitation signals. In this work, an analytical study of compression effects in amplifiers due to excitation signals composed of several tones is reported. Moreover, LNA nonlinear characteristics, as AM-AM, total distortion, and power to distortion ratio, have been obtained by simulation and measurement with wide-band Gaussian-noise excitation signals. This kind of signal can be considered as a limit case of a multitone signal, when the number of tones is very high. The work is illustrated by means of the extraction of realistic nonlinear characteristics, through simulation and measurement, of a 31 GHz back-end module LNA used in the radiometer of the QUIJOTE (Q U I JOint TEnerife) CMB experiment. PMID:20687750

  4. Low-noise kinetic inductance traveling-wave amplifier using three-wave mixing

    NASA Astrophysics Data System (ADS)

    Vissers, M. R.; Erickson, R. P.; Ku, H.-S.; Vale, Leila; Wu, Xian; Hilton, G. C.; Pappas, D. P.

    2016-01-01

    We have fabricated a wide-bandwidth, high dynamic range, low-noise cryogenic amplifier based on a superconducting kinetic inductance traveling-wave device. The device was made from NbTiN and consisted of a long, coplanar waveguide on a silicon chip. By adding a DC current and an RF pump tone, we are able to generate parametric amplification using three-wave mixing (3WM). The devices exhibit gain of more than 15 dB across an instantaneous bandwidth from 4 to 8 GHz. The total usable gain bandwidth, including both sides of the signal-idler gain region, is more than 6 GHz. The noise referred to the input of the devices approaches the quantum limit, with less than 1 photon excess noise. We compare these results directly to the four-wave mixing amplification mode, i.e., without DC-biasing. We find that the 3WM mode allows operation with the pump at lower RF power and at frequencies far from the signal. We have used this knowledge to redesign the amplifiers to utilize primarily 3WM amplification, thereby allowing for direct integration into large scale qubit and detector applications.

  5. Low noise and high CMRR front-end amplifier dedicated to portable EEG acquisition system.

    PubMed

    Chebli, Robert; Sawan, Mohamad

    2013-01-01

    This paper concerns the design and implementation of a fully integrated low noise and high CMRR rail-to-rail preamplifier dedicated to EEG acquisition channel. The preamplification technique is based on two complementary CMOS True Logarithmic Amplifier (TLA) stages connected in parallel. The TLA largely amplifies small amplitude of EEG signals, and moderately the large amplitude ones created during epileptic. A chopper stabilization technique is used to filter the 1/ƒ noise and the DC offset voltage of the input CMOS transistors and to increase the common-mode rejection ratio (CMRR). Due to the TLA structure, a high CMRR and high power supply rejection ratio are achieved and the signal-to-noise ratio (of the channel is better enhanced). To snugly fit the ADC input window to the EEG signal magnitude a new programming gain approach is implemented. Also, a chopper spike filter is used to cancel the spike voltages generated by the charge injections of modulator/demodulator switches. The proposed preamplifier is implemented in 0.18 µm CMOS technology. Post-layout simulation results exhibit 253 dB @50/60 Hz as CMRR, 500 nVrms @100 Hz as input-referred noise while consuming 55 µA from a 1.8 V supply. PMID:24110240

  6. S-band low noise amplifier and 40 kW high power amplifier subsystems of Japanese Deep Space Earth Station

    NASA Astrophysics Data System (ADS)

    Honma, K.; Handa, K.; Akinaga, W.; Doi, M.; Matsuzaki, O.

    This paper describes the design and the performance of the S-band low noise amplifier and the S-band high power amplifier that have been developed for the Usuda Deep Space Station of the Institute of Space and Astronautical Science (ISAS), Japan. The S-band low noise amplifier consists of a helium gas-cooled parametric amplifier followed by three-stage FET amplifiers and has a noise temperature of 8 K. The high power amplifier is composed of two 28 kW klystrons, capable of transmitting 40 kW continuously when two klystrons are combined. Both subsystems are operating quite satisfactorily in the tracking of Sakigake and Suisei, the Japanese interplanetary probes for Halley's comet exploration, launched by ISAS in 1985.

  7. Method and apparatus for linear low-frequency feedback in monolithic low-noise charge amplifiers

    DOEpatents

    DeGeronimo, Gianluigi

    2006-02-14

    A charge amplifier includes an amplifier, feedback circuit, and cancellation circuit. The feedback circuit includes a capacitor, inverter, and current mirror. The capacitor is coupled across the signal amplifier, the inverter is coupled to the output of the signal amplifier, and the current mirror is coupled to the input of the signal amplifier. The cancellation circuit is coupled to the output of the signal amplifier. A method of charge amplification includes providing a signal amplifier; coupling a first capacitor across the signal amplifier; coupling an inverter to the output of the signal amplifier; coupling a current mirror to the input of the signal amplifier; and coupling a cancellation circuit to the output of the signal amplifier. A front-end system for use with radiation sensors includes a charge amplifier and a current amplifier, shaping amplifier, baseline stabilizer, discriminator, peak detector, timing detector, and logic circuit coupled to the charge amplifier.

  8. Performance of a Y-Ba-Cu-O superconducting filter/GaAs low noise amplifier hybrid circuit

    NASA Technical Reports Server (NTRS)

    Bhasin, Kul B.; Toncich, S. S.; Chorey, C. M.; Bonetti, R. R.; Williams, A. E.

    1992-01-01

    A superconducting 7.3 GHz two-pole microstrip bandpass filter and a GaAs low noise amplifier (LNA) were combined into a hybrid circuit and characterized at liquid nitrogen temperatures. This superconducting/seismology circuit's performance was compared to a gold filter/GaAs LNA hybrid circuit. The superconducting filter/GaAs LNA hybrid circuit showed higher gain and lower noise figure than its gold counterpart.

  9. Performance of a Y-Ba-Cu-O superconducting filter/GaAs low noise amplifier hybrid circuit

    NASA Technical Reports Server (NTRS)

    Bhasin, K. B.; Toncich, S. S.; Chorey, C. M.; Bonetti, R. R.; Williams, A. E.

    1992-01-01

    A superconducting 7.3 GHz two-pole microstrip bandpass filter and a GaAs low noise amplifier (LNA) were combined into an active circuit and characterized at liquid nitrogen temperatures. This superconducting/semiconducting circuit's performance was compared to a gold filter/GaAs LNA hybrid circuit. The superconducting filter/GaAs LNA hybrid circuit showed higher gain and lower noise figure than its gold counterpart.

  10. Radio astronomy ultra-low-noise amplifier for operation at 91 cm wavelength in high RFI environment

    NASA Astrophysics Data System (ADS)

    Korolev, A. M.; Zakharenko, V. V.; Ulyanov, O. M.

    2016-02-01

    An ultra-low-noise input amplifier intended for a use in a radio telescope operating at 91 cm wavelength is presented. The amplifier noise temperatures are 12.8 ± 1.5 and 10.0 ± 1.5 K at ambient temperatures of 293 and 263 K respectively. The amplifier does not require cryogenic cooling. It can be quickly put in operation thus shortening losses in the telescope observation time. High linearity of the amplifier (output power at 1 dB gain compression P1dB ≥ 22 dBm, output third order intercept point OIP3 ≥ 37 dBm) enables the telescope operation in highly urbanized and industrialized regions. To obtain low noise characteristics along with high linearity, high-electron-mobility field-effect transistors were used in parallel in the circuit developed. The transistors used in the amplifier are cost-effective and commercially available. The circuit solution is recommended for similar devices working in ultra-high frequency band.

  11. Computer simulations of low noise states in a high-power crossed-field amplifier

    SciTech Connect

    Chernin, D.P.

    1996-11-01

    A large body of experimental data has been accumulated over the past 15 years or so on the remarkable ability of both magnetrons and CFA`s to operate under certain conditions at noise levels comparable to those achieved in linear beam tubes. The physical origins of these low noise states have been the subjects of considerable speculation, fueled at least in part by results from computer simulation. While computer models have long been able to predict basic operating parameters like gain, efficiency, and peak power dissipation on electrode surfaces with reasonable accuracy, it is only within the past few years that any success could be reported on the simulation of noise. SAIC`s MASK code, a 2{1/2}-D particle-in-cell code, has been able to compute total, integrated noise power to an accuracy of {+-} a few dB in a high-power CFA, operating with a typical intra-pulse spectral noise density of {approximately}47--50 dB/MHz. Under conditions that produced low noise ({approximately}60--100 dB/MHz) in laboratory experiments, the MASK code has been, until now, unable to reproduce similar results. The present paper reports the first successful production of a very low noise state in a CFA simulation using the MASK code. The onset of this low noise state is quite sudden, appearing abruptly as the current is raised to a point near which the cathode operates as nearly emission limited. This behavior is similar to that seen in an experimentally observed transition between low noise and high noise operation in the SFD-266, a Varian[CPI] low noise CFA. Some comments are made concerning the nature of the noise as observed in the simulation and in the laboratory.

  12. Recent Advances In Cryogenic Monolithic Millimeter-wave Integrated Circuit (MMIC) Low Noise Amplifiers For Astrophysical Observations

    NASA Astrophysics Data System (ADS)

    Samoska, Lorene; Church, S.; Cleary, K.; Gaier, T.; Gawande, R.; Kangaslahti, P.; Lawrence, C.; Readhead, A.; Reeves, R.; Seiffert, M.; Sieth, M.; Varonen, M.; Voll, P.

    2012-05-01

    In this work, we discuss advances in high electron mobility transistor (HEMT) low noise amplifier (LNA) monolithic millimeter-wave integrated circuits (MMICs) for use as front end amplifiers in ultra-low noise receivers. Applications include focal plane arrays for studying the polarization of the cosmic microwave background radiation and foreground separation, receiver arrays for molecular spectroscopy, and high redshift CO surveys for probing the epoch of reionization. Recent results and a summary of best indium phosphide (InP) low noise amplifier data will be presented. Cryogenic MMIC LNAs using state-of-the-art InP technology have achieved record performance, and have advantages over other detectors in the 30-300 GHz range. InP MMIC LNAs operate at room temperature and may achieve near-optimum performance at 20K, a temperature readily achieved with modern cryo-coolers. In addition, wide-bandwidth LNAs are suitable for heterodyne applications as well as direct detector applications. Recent results include Ka-band MMICs with 15K noise temperature performance, and Q-Band MMICs with on-wafer measured cryogenic noise of 12K at 38 GHz. In addition, W-Band amplifiers with 25K noise temperature at 95 GHz will be presented, as well as wide-band LNAs with noise temperature below 45K up to 116 GHz. At higher frequencies, we will discuss progress on MMIC LNAs and receiver modules in G-Band (140-220 GHz), where our group has achieved less than 60K receiver noise temperature at 166 GHz. We will address extending the high performance of these MMIC LNAs to even higher frequencies for spectroscopic surveys, and make projections on future performance given current trends. These MMIC amplifiers can play a key role in future ground-based and space-based instruments for astrophysical observations.

  13. Cryogenically cooled low-noise amplifier for radio-astronomical observations and centimeter-wave deep-space communications systems

    NASA Astrophysics Data System (ADS)

    Vdovin, V. F.; Grachev, V. G.; Dryagin, S. Yu.; Eliseev, A. I.; Kamaletdinov, R. K.; Korotaev, D. V.; Lesnov, I. V.; Mansfeld, M. A.; Pevzner, E. L.; Perminov, V. G.; Pilipenko, A. M.; Sapozhnikov, B. D.; Saurin, V. P.

    2016-01-01

    We report a design solution for a highly reliable, low-noise and extremely efficient cryogenically cooled transmit/receive unit for a large antenna system meant for radio-astronomical observations and deep-space communications in the X band. We describe our design solution and the results of a series of laboratory and antenna tests carried out in order to investigate the properties of the cryogenically cooled low-noise amplifier developed. The transmit/receive unit designed for deep-space communications (Mars missions, radio observatories located at Lagrangian point L2, etc.) was used in practice for communication with live satellites including "Radioastron" observatory, which moves in a highly elliptical orbit.

  14. The present status and future development of low noise amplifiers for satellite communications

    NASA Astrophysics Data System (ADS)

    Akinaga, W.; Handa, K.; Fujiki, Y.; Fukuda, S.; Haga, I.

    The LNAs for use in satellite communications have made remarkable progress in recent years. This paper describes the present status and future prospects of the two principal LNA types, the parametric LNA and the GaAs FET LNA, operating in the 2 GHz band through millimetric wavelength range, as regards their noise temperature characteristics. In a few years to come, the parametric LNA and the GaAs FET LNA will be coexistent, but the former will be restricted to the cryogenically cooled and the super-low-noise thermoelectrically cooled type, while the latter will occupy the majority of the LNAs for satellite communications use.

  15. Low noise parametric amplifiers for radio astronomy observations at 18-21 cm wavelength

    NASA Technical Reports Server (NTRS)

    Kanevskiy, B. Z.; Veselov, V. M.; Strukov, I. A.; Etkin, V. S.

    1974-01-01

    The principle characteristics and use of SHF parametric amplifiers for radiometer input devices are explored. Balanced parametric amplifiers (BPA) are considered as the SHF signal amplifiers allowing production of the amplifier circuit without a special filter to achieve decoupling. Formulas to calculate the basic parameters of a BPA are given. A modulator based on coaxial lines is discussed as the input element of the SHF. Results of laboratory tests of the receiver section and long-term stability studies of the SHF sector are presented.

  16. Performance of a wideband GaAs low-noise amplifier at cryogenic temperatures

    NASA Technical Reports Server (NTRS)

    Toncich, S. S.; Bhasin, K. B.; Chen, T. K.; Claspy, P. C.

    1992-01-01

    The gain and noise figure performance of a GaAs amplifier at cryogenic temperatures has been studied. Results obtained indicate that a lower noise figure and a higher gain are induced by decreasing the temperature, while no significant change in the input 1-dB compression point is observed. Repeated temperature cycling had no adverse effect on the amplifier performance.

  17. Ultrastable low-noise current amplifier: A novel device for measuring small electric currents with high accuracy

    SciTech Connect

    Drung, D.; Krause, C.; Becker, U.; Scherer, H.; Ahlers, F. J.

    2015-02-15

    An ultrastable low-noise current amplifier (ULCA) is presented. The ULCA is a non-cryogenic instrument based on specially designed operational amplifiers and resistor networks. It involves two stages, the first providing a 1000-fold current gain and the second performing a current-to-voltage conversion via an internal 1 MΩ reference resistor or, optionally, an external standard resistor. The ULCA’s transfer coefficient is highly stable versus time, temperature, and current amplitude within the full dynamic range of ±5 nA. The low noise level of 2.4 fA/√Hz helps to keep averaging times short at small input currents. A cryogenic current comparator is used to calibrate both input current gain and output transresistance, providing traceability to the quantum Hall effect. Within one week after calibration, the uncertainty contribution from short-term fluctuations and drift of the transresistance is about 0.1 parts per million (ppm). The long-term drift is typically 5 ppm/yr. A high-accuracy variant is available that shows improved stability of the input gain at the expense of a higher noise level of 7.5 fA/√Hz. The ULCA also allows the traceable generation of small electric currents or the calibration of high-ohmic resistors.

  18. Ultrastable low-noise current amplifier: A novel device for measuring small electric currents with high accuracy

    NASA Astrophysics Data System (ADS)

    Drung, D.; Krause, C.; Becker, U.; Scherer, H.; Ahlers, F. J.

    2015-02-01

    An ultrastable low-noise current amplifier (ULCA) is presented. The ULCA is a non-cryogenic instrument based on specially designed operational amplifiers and resistor networks. It involves two stages, the first providing a 1000-fold current gain and the second performing a current-to-voltage conversion via an internal 1 MΩ reference resistor or, optionally, an external standard resistor. The ULCA's transfer coefficient is highly stable versus time, temperature, and current amplitude within the full dynamic range of ±5 nA. The low noise level of 2.4 fA/√Hz helps to keep averaging times short at small input currents. A cryogenic current comparator is used to calibrate both input current gain and output transresistance, providing traceability to the quantum Hall effect. Within one week after calibration, the uncertainty contribution from short-term fluctuations and drift of the transresistance is about 0.1 parts per million (ppm). The long-term drift is typically 5 ppm/yr. A high-accuracy variant is available that shows improved stability of the input gain at the expense of a higher noise level of 7.5 fA/√Hz. The ULCA also allows the traceable generation of small electric currents or the calibration of high-ohmic resistors.

  19. Ultrastable low-noise current amplifier: a novel device for measuring small electric currents with high accuracy.

    PubMed

    Drung, D; Krause, C; Becker, U; Scherer, H; Ahlers, F J

    2015-02-01

    An ultrastable low-noise current amplifier (ULCA) is presented. The ULCA is a non-cryogenic instrument based on specially designed operational amplifiers and resistor networks. It involves two stages, the first providing a 1000-fold current gain and the second performing a current-to-voltage conversion via an internal 1 MΩ reference resistor or, optionally, an external standard resistor. The ULCA's transfer coefficient is highly stable versus time, temperature, and current amplitude within the full dynamic range of ±5 nA. The low noise level of 2.4 fA/√Hz helps to keep averaging times short at small input currents. A cryogenic current comparator is used to calibrate both input current gain and output transresistance, providing traceability to the quantum Hall effect. Within one week after calibration, the uncertainty contribution from short-term fluctuations and drift of the transresistance is about 0.1 parts per million (ppm). The long-term drift is typically 5 ppm/yr. A high-accuracy variant is available that shows improved stability of the input gain at the expense of a higher noise level of 7.5 fA/√Hz. The ULCA also allows the traceable generation of small electric currents or the calibration of high-ohmic resistors. PMID:25725866

  20. In-circuit-measurement of parasitic elements in high gain high bandwidth low noise transimpedance amplifiers.

    PubMed

    Cochems, P; Kirk, A; Zimmermann, S

    2014-12-01

    Parasitic elements play an important role in the development of every high performance circuit. In the case of high gain, high bandwidth transimpedance amplifiers, the most important parasitic elements are parasitic capacitances at the input and in the feedback path, which significantly influence the stability, the frequency response, and the noise of the amplifier. As these parasitic capacitances range from a few picofarads down to only a few femtofarads, it is nearly impossible to measure them accurately using traditional LCR meters. Unfortunately, they also cannot be easily determined from the transfer function of the transimpedance amplifier, as it contains several overlapping effects and its measurement is only possible when the circuit is already stable. Therefore, we developed an in-circuit measurement method utilizing minimal modifications to the input stage in order to measure its parasitic capacitances directly and with unconditional stability. Furthermore, using the data acquired with this measurement technique, we both proposed a model for the complicated frequency response of high value thick film resistors as they are used in high gain transimpedance amplifiers and optimized our transimpedance amplifier design. PMID:25554310

  1. Low-noise wide-band amplifiers for stochastic beam cooling experiments

    SciTech Connect

    Leskovar, B.; Lo, C.C.

    1982-09-05

    Noise characteristics of the continuous-wave wide-band amplifier systems for stochastic beam cooling experiments are presented. Also, the noise performance, bandwidth capability and gain stability of components used in these amplifiers are summarized and compared in the 100 MHz to 40 GHz frequency range. This includes bipolar and field-effect transistors, parametric amplifier, Schottky diode mixer and maser. Measurements of the noise characteristics and scattering parameters of variety GaAs FETs as a function of ambient temperature are also given. Performance data and design information are presented on a broadband 150-500 MHz preamplifier having noise temperature of approximately 35/sup 0/K at ambient temperature of 20/sup 0/K. An analysis of preamplifier stability based on scattering parameters concept is included.

  2. Low noise, tunable Ho:fiber soliton oscillator for Ho:YLF amplifier seeding

    NASA Astrophysics Data System (ADS)

    Li, Peng; Ruehl, Axel; Bransley, Colleen; Hartl, Ingmar

    2016-06-01

    We present a passively mode-locked, tunable soliton Ho:fiber ring oscillator, optimized for seeding of holmium-doped yttrium lithium flouride (Ho:YLF) amplifiers. The oscillator is independently tunable in central wavelength and spectral width from 2040 to 2070 nm and from 5 to 10 nm, respectively. At all settings the pulse energy within the soliton is around 800 pJ. The soliton oscillator was optimized to fully meet the spectral requirements for seeding Ho:YLF amplifiers. Its Kelly sidebands are located outside the amplifier gain spectrum, resulting in a train of about 1 ps long pedestal-free pulses with relative intensity noise of only 0.13% RMS when integrated from 1 Hz to Nyquist frequency.

  3. Low-noise Raman fiber amplifier pumped by semiconductor disk laser.

    PubMed

    Chamorovskiy, A; Rautiainen, J; Rantamäki, A; Okhotnikov, O G

    2011-03-28

    A 1.3 µm Raman fiber amplifier pumped by 1.22 µm semiconductor disk laser in co-propagation geometry is demonstrated. Measured relative intensity noise of -148 dB/Hz over frequency range up to 3.5 GHz was measured at 900 mW of pump power. 9 dB gain was achieved with co-propagating pumping geometry with less than 2 dB additional noise induced by amplifier to the signal. Nearly shot-noise-limited operation of semiconductor disk laser combined with the diffraction-limited beam allows for efficient core-pumping of the single-mode fiber Raman amplifiers and represents a highly practical approach which takes full advantage of co-propagating pumping. PMID:21451669

  4. Design and measurement of an integrated wideband radio frequency low-noise amplifier for terrestrial digital television applications

    NASA Astrophysics Data System (ADS)

    Albasha, Lutfi

    2010-05-01

    In this article, the design and measurement details of a wideband low-noise amplifier (LNA) are presented. The LNA was successfully designed to operate over very high and ultra high frequency (VHF and UHF) ranges according to Digital TV (DVB-T) specifications. The novelty of the design lies in the achievement of low noise figure (NF) and high reverse isolation level across a wide bandwidth despite the resistive feedback topology. The latter was required in order to integrate the front-end block with a direct-conversion receiver. A measured large-signal compression point of P1dB = -10 dBm and a small-signal gain of 16 dB with gain flatness of <1 dB ripple, have all met commercial specifications tested over corners. The NF achieved was better than that specified and was less than 2 dB across the bandwidth. This front-end block was implemented in a commercial 0.25 μm Si BiCMOS process (f T = 20 GHz). The article discusses the measurement uncertainties imposed by the wide bandwidth, particularly in NF measurements, and the techniques adopted in this work to mitigate the errors imposed.

  5. A low-noise instrumentation amplifier with DC suppression for recording ENG signals.

    PubMed

    Paraskevopoulou, Sivylla E; Eftekhar, Amir; Kulasekeram, Nishanth; Toumazou, Christofer

    2015-08-01

    This paper presents an AC-coupled instrumentation amplifier for electroneurogram (ENG) activity recording. For this design, we evaluate gain and noise requirements based on interference sources (electrodes, power line, EMG). The circuit has been implemented in a commercially-available 0.35μm CMOS technology with total power consumption 460μW. The amplifier achieves CMRR 107 dB and integrated input referred noise 940 nV. The gain is 63 dB and the bandwidth is 0.5 Hz- 13 kHz. The chosen topology enables to minimise on-chip capacitance (only 27 pF), with a total chip area of 0.4mm2. PMID:26736847

  6. Comparison of cryogenic W band low noise amplifier based on different III-V HEMT foundry process and technologies

    NASA Astrophysics Data System (ADS)

    Valenziano, L.; Zannoni, M.; Mariotti, S.; Cremonini, A.; De Rosa, A.; Banfi, S.; Baó, A.; Gervasi, M.; Limiti, E.; Passerini, A.; Schiavone, F.

    2014-07-01

    We present the results of a development activity for cryogenic Low Noise Amplifiers based on HEMT technology for ground based and space-borne application. We have developed and realized two LNA design in W band, based on m-HEMT technology. MMIC chips have been manufactured by European laboratories and companies and assembled in test modules by our team. We compare performances with other technologies and manufacturers. LNA RF properties (noise figures, S-parameters) have been measured at room and cryogenic temperature and test results are reported in this paper. Performance are compared with those of state-of-the-art devices, as available in the literature. Strengths and improvements of this project are also discussed.

  7. FM notch filter in front - and - behind the low noise amplifier of a Callisto Radio Spectrometer in Gauribidanur, India

    NASA Astrophysics Data System (ADS)

    Monstein, C.

    2014-03-01

    In the framework of IHY2007 a Callisto spectrometer [Benz(2004)] was installed and set into operation at the location of the solar heliograph in Gauribidanur, India. At that time the level of radio frequency interference (RFI) was amazingly low. In recent years more and more FM broadcast transmitters were installed with high power compared to the requirements of radio astronomical observations. So, the spectral observations with Callisto experienced more and more interference by these FM transmitters. Recently an FM-notch filter was installed between the low noise amplifier and Callisto, but it did not work out. The notch filter was then moved to the input of the LNA and the result was much better, as expected from theoretical concepts.

  8. Aspects of the design of low noise, negative resistance, reflection mode transistor amplifiers

    NASA Astrophysics Data System (ADS)

    Gardner, Peter; Paul, Dipak K.

    1991-11-01

    The authors consider the use of microwave transistors in negative resistance reflection mode and present the conditions for optimum noise performance. Possible advantages include the possibility of higher gain in the millimeter-wave region, which can be achieved by absorbing the parasitic common lead inductance into the feedback circuit designed to generate the negative resistance, and the existence of a failsafe mode of operation, in that the failure of the active device or its power supply is likely to lead a low return loss, resulting in a small insertion loss through the amplifiers, which may permit continued, although degraded, system operation. The latter potential advantage has proved to be of interest to radar system designers.

  9. Low Noise Amplifiers

    NASA Technical Reports Server (NTRS)

    Petty, S. M.; Trowbridge, D. L.

    1983-01-01

    One of the great technical challenges facing the Deep Space Network is receiving signals from a severely weight limited spacecraft hundreds of thousands to billions of kilometers from Earth. This weight limitation has always imposed strict limitations on the size of the spacecraft antenna and the amount of transmitter power radiated. The communication burden is placed upon the ground systems of the Deep Space Network which must recover an extremely weak signal in the presence of nearly overwhelming amounts of noise. Two key parameters that determine the signal to noise ratio of a received signal using a deep space station are the collecting area and efficiency of the antenna, and the amount of noise which is generated in, as well as allowed to enter in, the antenna-mounted receiver. These parameters are used to describe the relative ability of a deep space station to receive weak signals. As spacecraft to Earth communication distances have increased, the Deep Space Network engages in a relentless effort to increase the figure of merit through larger and more efficient antennas, higher frequencies, and lower system noise temperature.

  10. Low noise amplifiers

    NASA Astrophysics Data System (ADS)

    Petty, S. M.; Trowbridge, D. L.

    1983-07-01

    One of the great technical challenges facing the Deep Space Network is receiving signals from a severely weight limited spacecraft hundreds of thousands to billions of kilometers from Earth. This weight limitation has always imposed strict limitations on the size of the spacecraft antenna and the amount of transmitter power radiated. The communication burden is placed upon the ground systems of the Deep Space Network which must recover an extremely weak signal in the presence of nearly overwhelming amounts of noise. Two key parameters that determine the signal to noise ratio of a received signal using a deep space station are the collecting area and efficiency of the antenna, and the amount of noise which is generated in, as well as allowed to enter in, the antenna-mounted receiver. These parameters are used to describe the relative ability of a deep space station to receive weak signals. As spacecraft to Earth communication distances have increased, the Deep Space Network engages in a relentless effort to increase the figure of merit through larger and more efficient antennas, higher frequencies, and lower system noise temperature.

  11. Characteristics of a dye laser amplifier transversely pumped by copper vapor lasers with a two-dimensional calculation model

    SciTech Connect

    Sugiyama, A.; Nakayama, T.; Kato, M.; Maruyama, Y.

    1997-08-01

    A two-dimensional rate equation model, taking into consideration the transverse absorption loss of pump laser power, is proposed to evaluate the characteristics of a dye laser amplifier with a large input laser beam diameter pumped by high average power copper vapor lasers. The calculations are in good agreement with the measurements taken with a Rhodamine 6G dye, and the model can be used for evaluation of the dye concentration at any wavelength. {copyright} 1997 Optical Society of America

  12. A CMOS power-efficient low-noise current-mode front-end amplifier for neural signal recording.

    PubMed

    Wu, Chung-Yu; Chen, Wei-Ming; Kuo, Liang-Ting

    2013-04-01

    In this paper, a new current-mode front-end amplifier (CMFEA) for neural signal recording systems is proposed. In the proposed CMFEA, a current-mode preamplifier with an active feedback loop operated at very low frequency is designed as the first gain stage to bypass any dc offset current generated by the electrode-tissue interface and to achieve a low high-pass cutoff frequency below 0.5 Hz. No reset signal or ultra-large pseudo resistor is required. The current-mode preamplifier has low dc operation current to enhance low-noise performance and decrease power consumption. A programmable current gain stage is adopted to provide adjustable gain for adaptive signal scaling. A following current-mode filter is designed to adjust the low-pass cutoff frequency for different neural signals. The proposed CMFEA is designed and fabricated in 0.18-μm CMOS technology and the area of the core circuit is 0.076 mm(2). The measured high-pass cutoff frequency is as low as 0.3 Hz and the low-pass cutoff frequency is adjustable from 1 kHz to 10 kHz. The measured maximum current gain is 55.9 dB. The measured input-referred current noise density is 153 fA /√Hz , and the power consumption is 13 μW at 1-V power supply. The fabricated CMFEA has been successfully applied to the animal test for recording the seizure ECoG of Long-Evan rats. PMID:23853293

  13. Design of Low-Noise Output Amplifiers for P-channel Charge-Coupled Devices Fabricated on High-Resistivity Silicon

    SciTech Connect

    Haque, S; Frost, F Dion R.; Groulx, R; Holland, S E; Karcher, A; Kolbe, W F; Roe, N A; Wang, G; Yu, Y

    2011-12-22

    We describe the design and optimization of low-noise, single-stage output amplifiers for p-channel charge-coupled devices (CCDs) used for scientific applications in astronomy and other fields. The CCDs are fabricated on high-resistivity, 4000–5000 -cm, n-type silicon substrates. Single-stage amplifiers with different output structure designs and technologies have been characterized. The standard output amplifier is designed with an n{sup +} polysilicon gate that has a metal connection to the sense node. In an effort to lower the output amplifier readout noise by minimizing the capacitance seen at the sense node, buried-contact technology has been investigated. In this case, the output transistor has a p{sup +} polysilicon gate that connects directly to the p{sup +} sense node. Output structures with buried-contact areas as small as 2 μm × 2 μm are characterized. In addition, the geometry of the source-follower transistor was varied, and we report test results on the conversion gain and noise of the various amplifier structures. By use of buried-contact technology, better amplifier geometry, optimization of the amplifier biases and improvements in the test electronics design, we obtain a 45% reduction in noise, corresponding to 1.7 e{sup -} rms at 70 kpixels/sec.

  14. A low-noise transimpedance amplifier for the detection of “Violin-Mode” resonances in advanced Laser Interferometer Gravitational wave Observatory suspensions

    SciTech Connect

    Lockerbie, N. A.; Tokmakov, K. V.

    2014-11-15

    This paper describes the design and performance of an extremely low-noise differential transimpedance amplifier, which takes its two inputs from separate photodiodes. The amplifier was planned to serve as the front-end electronics for a highly sensitive shadow-displacement sensing system, aimed at detecting very low-level “Violin-Mode” (VM) oscillations in 0.4 mm diameter by 600 mm long fused-silica suspension fibres. Four such highly tensioned fibres support the 40 kg test-masses/mirrors of the Advanced Laser Interferometer Gravitational wave Observatory interferometers. This novel design of amplifier incorporates features which prevent “noise-gain peaking” arising from large area photodiode (and cable) capacitances, and which also usefully separate the DC and AC photocurrents coming from the photodiodes. In consequence, the differential amplifier was able to generate straightforwardly two DC outputs, one per photodiode, as well as a single high-gain output for monitoring the VM oscillations—this output being derived from the difference of the photodiodes’ two, naturally anti-phase, AC photocurrents. Following a displacement calibration, the amplifier's final VM signal output was found to have an AC displacement responsivity at 500 Hz of (9.43 ± 1.20) MV(rms) m{sup −1}(rms), and, therefore, a shot-noise limited sensitivity to such AC shadow- (i.e., fibre-) displacements of (69 ± 13) picometres/√Hz at this frequency, over a measuring span of ±0.1 mm.

  15. A low-noise transimpedance amplifier for the detection of "Violin-Mode" resonances in Advanced Laser Interferometer Gravitational wave Observatory suspensions.

    PubMed

    Lockerbie, N A; Tokmakov, K V

    2014-11-01

    This paper describes the design and performance of an extremely low-noise differential transimpedance amplifier, which takes its two inputs from separate photodiodes. The amplifier was planned to serve as the front-end electronics for a highly sensitive shadow-displacement sensing system, aimed at detecting very low-level "Violin-Mode" (VM) oscillations in 0.4 mm diameter by 600 mm long fused-silica suspension fibres. Four such highly tensioned fibres support the 40 kg test-masses/mirrors of the Advanced Laser Interferometer Gravitational wave Observatory interferometers. This novel design of amplifier incorporates features which prevent "noise-gain peaking" arising from large area photodiode (and cable) capacitances, and which also usefully separate the DC and AC photocurrents coming from the photodiodes. In consequence, the differential amplifier was able to generate straightforwardly two DC outputs, one per photodiode, as well as a single high-gain output for monitoring the VM oscillations-this output being derived from the difference of the photodiodes' two, naturally anti-phase, AC photocurrents. Following a displacement calibration, the amplifier's final VM signal output was found to have an AC displacement responsivity at 500 Hz of (9.43 ± 1.20) MV(rms) m(-1)(rms), and, therefore, a shot-noise limited sensitivity to such AC shadow- (i.e., fibre-) displacements of (69 ± 13) picometres/√Hz at this frequency, over a measuring span of ±0.1 mm. PMID:25430131

  16. A low-noise transimpedance amplifier for the detection of "Violin-Mode" resonances in advanced Laser Interferometer Gravitational wave Observatory suspensions

    NASA Astrophysics Data System (ADS)

    Lockerbie, N. A.; Tokmakov, K. V.

    2014-11-01

    This paper describes the design and performance of an extremely low-noise differential transimpedance amplifier, which takes its two inputs from separate photodiodes. The amplifier was planned to serve as the front-end electronics for a highly sensitive shadow-displacement sensing system, aimed at detecting very low-level "Violin-Mode" (VM) oscillations in 0.4 mm diameter by 600 mm long fused-silica suspension fibres. Four such highly tensioned fibres support the 40 kg test-masses/mirrors of the Advanced Laser Interferometer Gravitational wave Observatory interferometers. This novel design of amplifier incorporates features which prevent "noise-gain peaking" arising from large area photodiode (and cable) capacitances, and which also usefully separate the DC and AC photocurrents coming from the photodiodes. In consequence, the differential amplifier was able to generate straightforwardly two DC outputs, one per photodiode, as well as a single high-gain output for monitoring the VM oscillations—this output being derived from the difference of the photodiodes' two, naturally anti-phase, AC photocurrents. Following a displacement calibration, the amplifier's final VM signal output was found to have an AC displacement responsivity at 500 Hz of (9.43 ± 1.20) MV(rms) m-1(rms), and, therefore, a shot-noise limited sensitivity to such AC shadow- (i.e., fibre-) displacements of (69 ± 13) picometres/√Hz at this frequency, over a measuring span of ±0.1 mm.

  17. Development of a Low-Noise High Common-Mode-Rejection Instrumentation Amplifier. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Rush, Kenneth; Blalock, T. V.; Kennedy, E. J.

    1975-01-01

    Several previously used instrumentation amplifier circuits were examined to find limitations and possibilities for improvement. One general configuration is analyzed in detail, and methods for improvement are enumerated. An improved amplifier circuit is described and analyzed with respect to common mode rejection and noise. Experimental data are presented showing good agreement between calculated and measured common mode rejection ratio and equivalent noise resistance. The amplifier is shown to be capable of common mode rejection in excess of 140 db for a trimmed circuit at frequencies below 100 Hz and equivalent white noise below 3.0 nv/square root of Hz above 1000 Hz.

  18. Cryogenic 36-45 GHz InP Low-Noise Amplifier MMIC's with Improved Noise Temperature by Eliminating Parasitic Parallel-Plate Modes

    NASA Astrophysics Data System (ADS)

    Nakano, Hiroshi; Shimizu, Takashi; Ohno, Takeshi; Hirachi, Yasutake; Kawaguchi, Noriyuki

    2012-08-01

    This paper describes cryogenic 36-45 GHz InP low-noise amplifier monolithic microwave integrated circuits (MMIC's) with an improved noise temperature by eliminating parasitic parallel-plate resonance modes. These MMIC's are used for a Radio Astronomical receiver, which needs the ultimate super low-noise and wide-band frequency characteristics, such as those in ALMA Band 1. The MMIC chips were designed in the coplanar waveguide (CPW), and mounted to the AlN substrate with a flip-chip assembly, which was promising compared to wire bonding. The flip-chip assemblies, however, are prone to cause the parasitic parallel plate resonance mode (PPM). The relationship between the S-parameters and the PPM was investigated by using a 3D-electromagnetic simulation of the simple transmission-line test-chip with the same chip size as that of the actual MMIC. In order to eliminate the PPM, additional bumps were mounted on the simple transmission-line test-chip, and the effect of these bumps was confirmed by the simulation. These results obtained from the simple transmission-line test-chip were applied to an actual MMIC chip assembly. The MMIC assembled with the additional bumps had no abnormality in the measured S-parameters, and the PPM had been eliminated up to 65 GHz. Moreover, the stability factor, K, became more than 2.4 over 36-45 GHz. This InP low-noise amplifier MMIC exhibited a gain of 15 dB and a noise temperature of 180-240 K at room temperature in the frequency range of 36-45 GHz. When cooled to 28 K, a gain of 17 dB and a noise temperature of 22-35 K were obtained at a power consumption of 4.7 mW over 36-45 GHz. A high-gain amplifier module consisting of two cascaded chips, exhibited a gain of 27-30 dB and a noise temperature of 25-30 K at the ambient temperature of 22 K in the frequency range of 41-45 GHz.

  19. Dose rate dependence of the current noise performance of an ultra-low noise precision bipolar operational amplifier

    SciTech Connect

    Hiemstra, D.M.

    1999-12-01

    The dose rate dependence of the current noise of a bipolar operational amplifier is presented. Total current noise performance degrades linearly with increasing dose rate. Generation-recombination, white and 1/f spectral components contribute to the degradation. The generation-recombination component is the most significant contributor to dose rate dependent current noise degradation.

  20. Low-noise RF-amplifier-free slab-coupled optical waveguide coupled optoelectronic oscillators: physics and operation.

    PubMed

    Loh, William; Yegnanarayanan, Siva; Plant, Jason J; O'Donnell, Frederick J; Grein, Matthew E; Klamkin, Jonathan; Duff, Shannon M; Juodawlkis, Paul W

    2012-08-13

    We demonstrate a 10-GHz RF-amplifier-free slab-coupled optical waveguide coupled optoelectronic oscillator (SCOW-COEO) system operating with low phase-noise (<-115 dBc/Hz at 1 kHz offset) and large sidemode suppression (>70 dB measurement-limited). The optical pulses generated by the SCOW-COEO exhibit 26.8-ps pulse width (post compression) with a corresponding spectral bandwidth of 0.25 nm (1.8X transform-limited). We also investigate the mechanisms that limit the performance of the COEO. Our measurements indicate that degradation in the quality factor (Q) of the optical cavity significantly impacts COEO phase-noise through increases in the optical amplifier relative intensity noise (RIN). PMID:23038585

  1. Low noise gain-clamped L-band erbium-doped fiber amplifier by utilizing fiber Bragg grating

    NASA Astrophysics Data System (ADS)

    Wang, Tianshu; Guo, Yubin; Yan, Hongwei; Wang, Yuhang; Wang, Ke

    2006-11-01

    A novel gain-clamped long wavelength band (L-band) erbium-doped fiber amplifier (EDFA) is proposed and experimented by using a fiber Bragg grating (FBG) at the input end of the amplifier. This design provides a good gain clamping and decreases noise effectively. It uses two sections of erbium-doped fiber (EDF) pumped by a 1480-nm laser diode (LD) for higher efficiency and lower noise figure (NF). The gain is clamped at 23 dB with a variation of 0.5 dB from input signal power of -30 to -8 dBm for 1589 nm and NF below 5 dB is obtained. At the longer wavelength in L-band higher gain is also obtained and the gain is clamped at 16 dB for 1614 nm effectively. Because the FBG injects a portion of backward amplified spontaneous emission (ASE) back into the system, the gain enhances 5 dB with inputting small signal.

  2. Enhancing the noise performance of monolithic microwave integrated circuit-based low noise amplifiers through the use of a discrete preamplifying transistor

    NASA Astrophysics Data System (ADS)

    McCulloch, Mark A.; Melhuish, Simon J.; Piccirillo, Lucio

    2015-01-01

    An approach to enhancing the noise performance of an InP monolithic microwave integrated circuit (MMIC)-based low noise amplifiers (LNA) through the use of a discrete 100-nm gate length InP high electron mobility transistor is outlined. This LNA, known as a transistor in front of MMIC (T + MMIC) LNA, possesses a gain in excess of 40 dB and an average noise temperature of 9.4 K across the band 27 to 33 GHz at a physical temperature of 8 K. This compares favorably with 14.5 K for an LNA containing an equivalent MMIC. A simple advanced design system model offering further insights into the operation of the LNA is also presented and the LNA is compared with the current state-of-the-art Planck LFI LNAs.

  3. SEMICONDUCTOR INTEGRATED CIRCUITS A 0.18 μm CMOS dual-band low power low noise amplifier for a global navigation satellite system

    NASA Astrophysics Data System (ADS)

    Bing, Li; Yiqi, Zhuang; Zhenrong, Li; Gang, Jin

    2010-12-01

    This paper presents a dual-band low noise amplifier for the receiver of a global navigation satellite system. The differences between single band and multi-band design methods are discussed. The relevant parameter analysis and the details of circuit design are presented. The test chip was implemented in a TSMC 0.18 μm 1P4M RF CMOS process. The LNA achieves a gain of 16.8 dB/18.9 dB on 1.27 GHz/1.575 GHz. The measured noise figure is around 1.5-1.7 dB on both bands. The LNA consumes less than 4.3 mA of current from a 1.8 V power supply. The measurement results show consistency with the design. And the LNA can fully satisfy the demands of the GNSS receiver.

  4. A 3.5-4.5 GHz Complementary Metal-Oxide-Semiconductor Ultrawideband Receiver Frontend Low-Noise Amplifier with On-Chip Integrated Antenna for Interchip Communication

    NASA Astrophysics Data System (ADS)

    Azhari, Afreen; Kimoto, Kentaro; Sasaki, Nobuo; Kikkawa, Takamaro

    2010-04-01

    Chip-to-chip ultrawideband (UWB) wireless interconnections are essential for reducing resistance capacitance (RC) delay in wired interconnections and three-dimensional (3D) highly integrated packaging. In this study, we demonstrated a wireless interchip signal transmission between two on-chip meander antennas on printed circuit board (PCB) for 1 to 20 mm transmission distances where the low power gain of each antenna due to a lossy Si substrate has been amplified by a low-noise amplifier (LNA). The measured result shows that the LNA produces 26 dB of improvement in antenna power gain at 4.5 GHz on a lossy Si substrate. Moreover, a Gaussian monocycle pulse with a center frequency of 2.75 GHz was also received by an on-chip antenna and amplified by the LNA. The LNA was integrated with an on-chip antenna on a Si substrate with a resistivity of 10 Ω·cm using 180 nm complementary metal-oxide-semiconductor (CMOS) technology. The investigated system is required for future single chip transceiver front ends, integrated with an on-chip antenna for 3D mounting on a printed circuit (PC) board.

  5. Two-Dimensional Organic Single Crystals with Scale Regulated, Phase-Switchable, Polymorphism-Dependent, and Amplified Spontaneous Emission Properties.

    PubMed

    Zhang, Zhenyu; Song, Xiaoxian; Wang, Shipan; Li, Feng; Zhang, Hongyu; Ye, Kaiqi; Wang, Yue

    2016-05-01

    The successful preparation of two-dimensional (2D) single crystals can promote the development of organic optoelectronic devices with excellent performance. A Schiff base compound salicylidene(4-dimethylamino)aniline with aggregation induced emission (AIE) property was employed as the building block to fabricate 2D thin single crystal plates with scales from around 50 μm to 1.5 cm. Yellow and red emissive polymorphs were concomitantly obtained during crystallization. The single-crystal-to-single-crystal (SC-to-SC) transformation from yellow polymorph to red one was demonstrated. Furthermore, both polymorphs exhibited amplified spontaneous emission (ASE) properties. Interestingly, the red polymorph displayed size-dependent ASE characteristics. The larger red polymorph showed near-infrared ASE with maximum at 706 nm, whereas the smaller one presented red ASE with maximum at 610 nm. These results suggest that the different scale single crystalline thin films with perfect optoelectronic properties may be fabricated by using the organic molecules with 2D assembly feature. PMID:27096197

  6. Advances In Cryogenic Monolithic Millimeter-wave Integrated Circuit (MMIC) Low Noise Amplifiers For CO Intensity Mapping and ALMA Band 2

    NASA Astrophysics Data System (ADS)

    Samoska, Lorene; Cleary, Kieran; Church, Sarah E.; Cuadrado-Calle, David; Fung, Andy; gaier, todd; gawande, rohit; Kangaslahti, Pekka; Lai, Richard; Lawrence, Charles R.; Readhead, Anthony C. S.; Sarkozy, Stephen; Seiffert, Michael D.; Sieth, Matthew

    2016-01-01

    We will present results of the latest InP HEMT MMIC low noise amplifiers in the 30-300 GHz range, with emphasis on LNAs and mixers developed for CO intensity mapping in the 40-80 GHz range, as well as MMIC LNAs suitable for ALMA Band 2 (67-90 GHz). The LNAs have been developed together with NGC in a 35 nm InP HEMT MMIC process. Recent results and a summary of best InP low noise amplifier data will be presented. This work describes technologies related to the detection and study of highly redshifted spectral lines from the CO molecule, a key tracer for molecular hydrogen. One of the most promising techniques for observing the Cosmic Dawn is intensity mapping of spectral-spatial fluctuations of line emission from neutral hydrogen (H I), CO, and [C II]. The essential idea is that instead of trying to detect line emission from individual galaxies, one measures the total line emission from a number of galaxies within the volume defined by a spectral-spatial pixel. Fluctuations from pixel to pixel trace large scale structure, and the evolution with redshift is revealed as a function of receiver frequency. A special feature of CO is the existence of multiple lines with a well-defined frequency relationship from the rotational ladder, which allows the possibility of cleanly separating the signal from other lines or foreground structure at other redshifts. Making use of this feature (not available to either HI or [C II] measurements) requires observing multiple frequencies, including the range 40-80 GHz, much of which is inaccessible from the ground or balloons.Specifically, the J=1->0 transition frequency is 115 GHz; J=2->1 is 230 GHz; J=3->2 is 345 GHz, etc. At redshift 7, these lines would appear at 14.4, 28.8, and 43.2 GHz, accessible from the ground. Over a wider range of redshifts, from 3 to 7, these lines would appear at frequencies from 14 to 86 GHz. A ground-based CO Intensity mapping experiment, COMAP, will utilize InP-based HEMT MMIC amplifier front ends in the

  7. Influence of gate metal engineering on small-signal and noise behaviour of silicon nanowire MOSFET for low-noise amplifiers

    NASA Astrophysics Data System (ADS)

    Gupta, Neha; Chaujar, Rishu

    2016-08-01

    In this paper, we have investigated the small-signal behaviour and RF noise performance of gate electrode workfunction engineered (GEWE) silicon nanowire (SiNW) MOSFET, and the results so obtained are simultaneously compared with SiNW and conventional MOSFET at THz frequency range. This work examines reflection and transmission coefficients, noise conductance, minimum noise figure and cross-correlation factor. Results reveal significant reduction in input/output reflection coefficient and an increase in forward/reverse transmission coefficient owing to improved transconductance in GEWE-SiNW in comparison with conventional counterparts. It is also observed that minimum noise figure and noise conductance of GEWE-SiNW is reduced by 17.4 and 31.2 %, respectively, in comparison with SiNW, thus fortifying its potential application for low-noise amplifiers (LNAs) at radio frequencies. Moreover, the efficacy of gate metal workfunction engineering is also studied and the results validate that tuning of workfunction difference results further improvement in device small-signal behaviour and noise performance.

  8. Low-noise cryogenic transmission line

    NASA Technical Reports Server (NTRS)

    Norris, D.

    1987-01-01

    New low-noise cryogenic input transmission lines have been developed for the Deep Space Network (DSN) at 1.668 GHz for cryogenically cooled Field Effect Transistors (FET) and High Electron Mobility Transistor (HEMT) amplifiers. These amplifiers exhibit very low noise temperatures of 5 K to 15 K, making the requirements for a low-noise input transmission line critical. Noise contribution to the total amplifier system from the low-noise line is less than 0.5 K for both the 1.668-GHz and 2.25-GHz FET systems. The 1.668-GHz input line was installed in six FET systems which were implemented in the DSN for the Venus Balloon Experiment. The 2.25-GHz input line has been implemented in three FET systems for the DSN 34-m HEF antennas, and the design is currently being considered for use at higher frequencies.

  9. Design and implementation of a 1-V transformer magnetic feedback low-noise amplifier (LNA) at 5-6 GHz, in a 90 nm complementary metal-oxide-semiconductor (CMOS) process

    NASA Astrophysics Data System (ADS)

    Kytonaki, Eleni-Sotiria; Simitsakis, Paschalis; Bazigos, Antonios; Papananos, Yannis

    2011-02-01

    In this study, a low-noise amplifier (LNA) suitable for low-voltage operation is presented. The LNA operates at a frequency range between 5 and 6 GHz. Its topology exploits magnetic feedback to achieve high reverse isolation and low noise performance without a significant degradation of the gain and linearity of the circuit. The design has been fabricated, considering full electrostatic discharge protection, in a modern 90 nm complementary metal-oxide-semiconductor process. The measured performance, at 5.4 GHz, shows a reverse isolation of -17.3 dB, a gain of 10.4 dB, a noise figure of 0.98 dB and an input intercept point of 1.4 dBm. The circuit dissipates 12.5 mW from a 1 V supply, while it occupies 0.162 mm2 of the die area.

  10. EHF low-noise FET receiver

    NASA Technical Reports Server (NTRS)

    Schellenberg, J. M.; Watkins, E. T.

    1983-01-01

    Extremely high frequency (EHF) receivers for military and NASA programs must be small, lightweight, and highly reliable. In connection with recent advances in the development of mm-wave FET devices and circuits, a basis has been obtained for the eventual replacement of diode mixer front-ends by FET preamplifiers in receivers up to 94 GHz. By placing a low noise amplifier in front of the mixer it is possible to achieve a lower system noise figure than that found in conventional mm-wave receivers. A broader bandwidth can also be provided. Attention is given to the receiver configuration, a low noise FET amplifier, an image rejection filter, a dual-gate FET mixer, a FET local oscillator, and a FET receiver.

  11. Ultra-low-noise microwave amplifiers

    NASA Technical Reports Server (NTRS)

    Clauss, R. C.; Trowbridge, D.

    1980-01-01

    The highlights of 20 years of maser use and development are presented. Masers discussed include cavity, traveling wave, K band, and S band. Noise temperatures measured since 1960 are summarized. Use of masers in the Deep Space Network is presented. Costs associated with the construction of masers systems are given.

  12. A 5.4-9.2 GHz 19.5 dB Complementary Metal-Oxide-Semiconductor Ultrawide-Band Receiver Front-End Low-Noise Amplifier

    NASA Astrophysics Data System (ADS)

    Azhari, Afreen; Kubota, Shinichi; Toya, Akihiro; Sasaki, Nobuo; Kikkawa, Takamaro

    2011-04-01

    In this work, we present an ultrawide-band (UWB) complementary metal-oxide-semiconductor (CMOS) low-noise amplifier (LNA) for wireless communication in the upper UWB band, that is, from 5.4-9.2 GHz bandwidth with a wide-band 50 Ω input matching network in front of the LNA. A three-stage cascode-topology-based LNA with high-transconductance MOS transistors, was employed to improve the voltage gain up to 23 dB at 7.5 GHz, with 4.5-9.2 GHz 3 dB bandwidth. The maximum output power S21 was 19.5 dB at 7.3 GHz, with 5.4-9.2 GHz 3 dB bandwidth. The input matching circuit was designed with a reduced number of passive elements, resulting in an input reflection coefficient S11 of less than -10 dB from 4.5-9.2 GHz. The noise figure of the LNA was as low as 3.5 dB and the input-referred third-order intercept point (IIP3) was -8 dBm. The LNA has output reflection coefficient S22 of less than -10 dB from 5-7 GHz and a good reverse isolation, that is, S12 of < -45 dB in the entire UWB, due to a cascode topology. The LNA was fabricated using 180 nm CMOS technology, which consumes 56 mW power at 1.8 V power supply. In this paper, we also demonstrate a wireless communication of 7 GHz Gaussian monocycle pulse (GMP) by horn antennas and the LNA from 20 cm transmission distance.

  13. 60 GHz low noise wideband receiver

    NASA Technical Reports Server (NTRS)

    Knust-Graichen, R. A.; Bui, L.

    1985-01-01

    The printed circuit and GaAs beam lead technology-based, low noise integrated receiver presented was developed for low cost space communications and operates in the 59-64 GHz range, using a phase-locked Gunn oscillator at 51.5 GHz. An IF output of 7.5-12.5 GHz is obtained. With the exception of the IF amplifier, and of the E-plane technology-based RF preselect filter, all circuits of the device employ suspended stripline construction.

  14. A high-speed 12-layer two-dimensional bar code detection system with wideband photodetection amplifier and balanced raster scanner

    NASA Astrophysics Data System (ADS)

    Wakaumi, Hiroo; Ajiki, Hiroshi

    1998-12-01

    A high-speed 12-layer 2D bar-code detection system (BCDS) consisting of a photodetection amplifier with an amplification-type current-voltage converter and a balanced raster scanner combined with the complementary light emission drive method for laser diodes, has been developed in order to provide both a high effective scanning speed and multi-layer bar-code detection. This BCDS performs 1,250 scan/s, which is two and a half times the scanning speed of a conventional bar-code detection system. A new theoretical modulation model that gives an accurate model for laser scanning beam traces obtained by the balanced raster scanner is proposed. This model allows an optimum BCDS to be designed easily.

  15. Low-noise nozzle valve

    NASA Technical Reports Server (NTRS)

    Gwin, Hal S. (Inventor); Aaron, James (Inventor)

    1990-01-01

    A low noise, variable discharage area, valve is constructed having opposed recesses within which a pair of gates are slidably disposed. Each of the gates is provided with upstream edges having a radius thereon, the radius enabling smooth, accelerated, low noise flow therebetween. The gates are further provided with tracks along each side, which in turn slide along splines set in the side walls of the valve. A threaded rod which rotates in a threaded insert in a rear wall of each of the gates, serves to move the gates within their respective recesses.

  16. Low-noise nozzle valve

    NASA Astrophysics Data System (ADS)

    Gwin, Hal S.; Aaron, James

    1990-09-01

    A low noise, variable discharage area, valve is constructed having opposed recesses within which a pair of gates are slidably disposed. Each of the gates is provided with upstream edges having a radius thereon, the radius enabling smooth, accelerated, low noise flow therebetween. The gates are further provided with tracks along each side, which in turn slide along splines set in the side walls of the valve. A threaded rod which rotates in a threaded insert in a rear wall of each of the gates, serves to move the gates within their respective recesses.

  17. Ultra low-noise charge coupled device

    NASA Technical Reports Server (NTRS)

    Janesick, James R. (Inventor)

    1993-01-01

    Special purpose CCD designed for ultra low-noise imaging and spectroscopy applications that require subelectron read noise floors, wherein a non-destructive output circuit operating near its 1/f noise regime is clocked in a special manner to read a single pixel multiple times. Off-chip electronics average the multiple values, reducing the random noise by the square-root of the number of samples taken. Noise floors below 0.5 electrons rms are possible in this manner. In a preferred embodiment of the invention, a three-phase CCD horizontal register is used to bring a pixel charge packet to an input gate adjacent a floating gate amplifier. The charge is then repeatedly clocked back and forth between the input gate and the floating gate. Each time the charge is injected into the potential well of the floating gate, it is sensed non-destructively. The floating gate amplifier is provided with a reference voltage of a fixed value and a pre-charge gate for resetting the amplifier between charge samples to a constant gain. After the charge is repeatedly sampled a selected number of times, it is transferred by means of output gates, back into the horizontal register, where it is clocked in a conventional manner to a diffusion MOSFET amplifier. It can then be either sampled (destructively) one more time or otherwise discarded.

  18. Support assembly for cryogenically coolable low-noise choke waveguide

    NASA Technical Reports Server (NTRS)

    Mccrea, F. E. (Inventor)

    1980-01-01

    A compact cryogenically coolable choked waveguide for low-noise input coupling into a cryogenically cooled device, such as a maser or parametric amplifier, utilizes coaxial stainless steel support tubes surrounding the waveguide and connected in cascade to provide a folded low thermal conduction path. The edges of the tubes connected are welded.

  19. Design of matching networks for low noise preamplifiers.

    PubMed

    Reykowski, A; Wright, S M; Porter, J R

    1995-06-01

    This paper discusses matching networks that minimize inductive coupling between the antennas within an array while simultaneously insuring minimum noise contributions from preamplifiers. Typical low noise preamplifier designs require a strong mismatch between the source impedance and the amplifier input impedance (reflection coefficient close to one) to achieve optimal noise performance. This is in contrast to the familiar impedance match known from communication theory where input and source impedances have complex conjugate values for maximizing the power transfer from source to amplifier. The high input reflection coefficient of low noise amplifiers can be exploited to reduce antenna currents by using lossless impedance transformations to create a high impedance at the coil terminals while simultaneously maintaining a low noise figure for the amplifier. The networks presented here constitute an improvement over previous work because they give additional freedoms regarding the values of the network components and the amplifier input impedance. The technique has been formalized and coded in MathCad, making the design of realizable networks a simple process. PMID:7651124

  20. The 30 GHz communications satellite low noise receiver

    NASA Astrophysics Data System (ADS)

    Steffek, L. J.; Smith, D. W.

    1983-10-01

    A Ka-band low noise front end in proof of concept (POC) model form for ultimate spaceborne communications receiver deployment was developed. The low noise receiver consists of a 27.5 to 30.0 GHz image enhanced mixer integrated with a 3.7 to 6.2 GHz FET low noise IF amplifier and driven by a self contained 23.8 GHz phase locked local oscillator source. The measured level of receiver performance over the 27.3 to 30.0 GHz RF/3.7 to 6.2 GHz IF band includes 5.5 to 6.5 dB (typ) SSB noise figure, 20.5 + or - 1.5 dB conversion gain and +23 dBm minimum third order two tone intermodulation output intercept point.

  1. The 30 GHz communications satellite low noise receiver

    NASA Technical Reports Server (NTRS)

    Steffek, L. J.; Smith, D. W.

    1983-01-01

    A Ka-band low noise front end in proof of concept (POC) model form for ultimate spaceborne communications receiver deployment was developed. The low noise receiver consists of a 27.5 to 30.0 GHz image enhanced mixer integrated with a 3.7 to 6.2 GHz FET low noise IF amplifier and driven by a self contained 23.8 GHz phase locked local oscillator source. The measured level of receiver performance over the 27.3 to 30.0 GHz RF/3.7 to 6.2 GHz IF band includes 5.5 to 6.5 dB (typ) SSB noise figure, 20.5 + or - 1.5 dB conversion gain and +23 dBm minimum third order two tone intermodulation output intercept point.

  2. Low-noise pulse conditioner

    DOEpatents

    Bird, David A.

    1983-01-01

    A low-noise pulse conditioner is provided for driving electronic digital processing circuitry directly from differentially induced input pulses. The circuit uses a unique differential-to-peak detector circuit to generate a dynamic reference signal proportional to the input peak voltage. The input pulses are compared with the reference signal in an input network which operates in full differential mode with only a passive input filter. This reduces the introduction of circuit-induced noise, or jitter, generated in ground referenced input elements normally used in pulse conditioning circuits, especially speed transducer processing circuits.

  3. Low noise lead screw positioner

    NASA Technical Reports Server (NTRS)

    Perkins, Gerald S. (Inventor)

    1986-01-01

    A very precise and low noise lead screw positioner, for positioning a retroreflector in an interferometer is described. A gas source supplies inert pressurized gas, that flows through narrow holes into the clearance space between a nut and the lead screw. The pressurized gas keeps the nut out of contact with the screw. The gas flows axially along the clearance space, into the environment. The small amount of inert gas flowing into the environment minimizes pollution. By allowing such flow into the environment, no seals are required between the end of the nut and the screw.

  4. Low noise charge ramp electrometer

    DOEpatents

    Morgan, John P.; Piper, Thomas C.

    1992-01-01

    An electrometer capable of measuring small currents without the use of a feedback resistor which tends to contribute a large noise factor to the measured data. The electrometer eliminates the feedback resistor through the use of a feedback capacitor located across the electrometer amplifier. The signal from the electrometer amplifier is transferred to a electrometer buffer amplifier which serves to transfer the signal to several receptors. If the electrometer amplifier is approaching saturation, the buffer amplifier signals a reset discriminator which energizes a coil whose magnetic field closes a magnetic relay switch which in turn resets or zeros the feedback capacitor. In turn, a reset complete discriminator restarts the measurement process when the electrometer amplifier approaches its initial condition. The buffer amplifier also transmits the voltage signal from the electrometer amplifier to a voltage-to-frequency converter. The signals from the voltage-to-frequency converter are counted over a fixed period of time and the information is relayed to a data processor. The timing and sequencing of the small current measuring system is under the control of a sequence control logic unit.

  5. Low noise charge ramp electrometer

    DOEpatents

    Morgan, J.P.; Piper, T.C.

    1992-10-06

    An electrometer capable of measuring small currents without the use of a feedback resistor which tends to contribute a large noise factor to the measured data. The electrometer eliminates the feedback resistor through the use of a feedback capacitor located across the electrometer amplifier. The signal from the electrometer amplifier is transferred to a electrometer buffer amplifier which serves to transfer the signal to several receptors. If the electrometer amplifier is approaching saturation, the buffer amplifier signals a reset discriminator which energizes a coil whose magnetic field closes a magnetic relay switch which in turn resets or zeros the feedback capacitor. In turn, a reset complete discriminator restarts the measurement process when the electrometer amplifier approaches its initial condition. The buffer amplifier also transmits the voltage signal from the electrometer amplifier to a voltage-to-frequency converter. The signals from the voltage-to-frequency converter are counted over a fixed period of time and the information is relayed to a data processor. The timing and sequencing of the small current measuring system is under the control of a sequence control logic unit. 2 figs.

  6. Two dimensional NMR spectroscopy

    SciTech Connect

    Schram, J.; Bellama, J.M.

    1988-01-01

    Two dimensional NMR represents a significant achievement in the continuing effort to increase solution in NMR spectroscopy. This book explains the fundamentals of this new technique and its analytical applications. It presents the necessary information, in pictorial form, for reading the ''2D NMR,'' and enables the practicing chemist to solve problems and run experiments on a commercial spectrometer by using the software provided by the manufacturer.

  7. Low-noise pulse conditioner

    DOEpatents

    Bird, D.A.

    1981-06-16

    A low-noise pulse conditioner is provided for driving electronic digital processing circuitry directly from differentially induced input pulses. The circuit uses a unique differential-to-peak detector circuit to generate a dynamic reference signal proportional to the input peak voltage. The input pulses are compared with the reference signal in an input network which operates in full differential mode with only a passive input filter. This reduces the introduction of circuit-induced noise, or jitter, generated in ground referenced input elements normally used in pulse conditioning circuits, especially speed transducer processing circuits. This circuit may be used for conditioning the sensor signal from the Fidler coil in a gas centrifuge for separation of isotopic gaseous mixtures.

  8. Two dimensional vernier

    NASA Technical Reports Server (NTRS)

    Juday, Richard D. (Inventor)

    1992-01-01

    A two-dimensional vernier scale is disclosed utilizing a cartesian grid on one plate member with a polar grid on an overlying transparent plate member. The polar grid has multiple concentric circles at a fractional spacing of the spacing of the cartesian grid lines. By locating the center of the polar grid on a location on the cartesian grid, interpolation can be made of both the X and Y fractional relationship to the cartesian grid by noting which circles coincide with a cartesian grid line for the X and Y direction.

  9. Low noise multiwasher superconducting interferometer

    SciTech Connect

    Carelli, P.; Castellano, M.G.; Torrioli, G.; Leoni, R.

    1998-01-01

    The dc-superconducting quantum interference device (SQUID) is a low-noise converter from magnetic flux to voltage which can have, in principle, an energy sensitivity near the quantum limit of {h_bar}/2. A critical parameter for the ideal performance is the device inductance, which must be kept as small as possible. Minimizing the SQUID inductance, however, is a major concern for a practical device; this requirement implies a small SQUID ring and hence magnetic coupling with an external signal is more difficult to achieve. Here we present an original scheme (called multiwasher) to circumvent this problem, and its implementation in an all-refractory thin-film device. Our scheme not only provides good magnetic coupling with a large input coil (0.5 {mu}H) and very low SQUID inductance, but also shielding from outside uniform fields, such as those generated by ambient disturbances. The measured coupled spectral energy sensitivity in the white region at about 1 kHz is 28{h_bar} at 4.2 K and 5.5{h_bar} in a pumped helium bath at 0.9 K. The flux noise spectral density at 0.1 Hz and 0.9 K is {Phi}{sub n}=1{times}10{sup {minus}6}{Phi}{sub 0}/{radical} (Hz) . {copyright} {ital 1998 American Institute of Physics.}

  10. Scalable, Low-Noise Architecture for Integrated Terahertz Imagers

    NASA Astrophysics Data System (ADS)

    Gergelyi, Domonkos; Földesy, Péter; Zarándy, Ákos

    2015-06-01

    We propose a scalable, low-noise imager architecture for terahertz recordings that helps to build large-scale integrated arrays from any field-effect transistor (FET)- or HEMT-based terahertz detector. It enhances the signal-to-noise ratio (SNR) by inherently enabling complex sampling schemes. The distinguishing feature of the architecture is the serially connected detectors with electronically controllable photoresponse. We show that this architecture facilitate room temperature imaging by decreasing the low-noise amplifier (LNA) noise to one-sixteenth of a non-serial sensor while also reducing the number of multiplexed signals in the same proportion. The serially coupled architecture can be combined with the existing read-out circuit organizations to create high-resolution, coarse-grain sensor arrays. Besides, it adds the capability to suppress overall noise with increasing array size. The theoretical considerations are proven on a 4 by 4 detector array manufactured on 180 nm feature sized standard CMOS technology. The detector array is integrated with a low-noise AC-coupled amplifier of 40 dB gain and has a resonant peak at 460 GHz with 200 kV/W overall sensitivity.

  11. The Alternative Low Noise Fan

    NASA Technical Reports Server (NTRS)

    Dittmar, James H.; Elliott, David M.; Jeracki, Robert J.; Moore, Royce D.; Parrott, Tony L.

    2000-01-01

    A 106 bladed fan with a design takeoff tip speed of 1100 ft/sec was hypothesized as reducing perceived noise because of the shift of the blade passing harmonics to frequencies beyond the perceived noise rating range. A 22 in. model of this Alternative Low Noise Fan, ALNF, was tested in the NASA Glenn 9x 15 Wind Tunnel. 'Me fan was tested with a 7 vane long chord stator assembly and a 70 vane conventional stator assembly in both hard and acoustically treated configurations. In addition a partially treated 7 vane configuration was tested wherein the acoustic material between the 7 long chord stators was made inactive. The noise data from the 106 bladed fan with 7 long chord stators in a hard configuration was shown to be around 4 EPNdB quieter than a low tip speed Allison fan at takeoff and around 5 EPNdB quieter at approach. Although the tone noise behaved as hypothesized, the majority of this noise reduction was from reduced broadband noise related to the large number of rotor blades. This 106 bladed ALNF is a research fan designed to push the technology limits and as such is probably not a practical device with present materials technology. However, a low tip speed fan with around 50 blades would be a practical device and calculations indicate that it could be 2 to 3 EPNdB quieter at takeoff and 3 to 4 EPNdB quieter at approach than the Allison fan. 7 vane data compared with 70 vane data indicated that the tone noise was controlled by rotor wake-stator interaction but that the broadband noise is probably controlled by the interaction of the rotor with incoming flows. A possible multiple pure tone noise reduction technique for a fan/acoustic treatment system was identified. The data from the fully treated configuration showed significant noise reductions over a large frequency range thereby providing a real tribute to this bulk absorber treatment design. The tone noise data with the partially treated 7 vane configuration indicated that acoustic material in the

  12. Note: Broadband low-noise photodetector for Pound-Drever-Hall laser stabilization

    NASA Astrophysics Data System (ADS)

    Potnis, Shreyas; Vutha, Amar C.

    2016-07-01

    The Pound-Drever-Hall laser stabilization technique requires a fast, low-noise photodetector. We present a simple photodetector design that uses a transformer as an intermediary between a photodiode and cascaded low-noise radio-frequency amplifiers. Our implementation using a silicon photodiode yields a detector with 50 MHz bandwidth, gain >105 V/A, and input current noise <4 pA/ √{ Hz } , allowing us to obtain shot-noise-limited performance with low optical power.

  13. Cryogenetically Cooled Field Effect Transistors for Low-Noise Systems

    NASA Technical Reports Server (NTRS)

    Wollack, Edward J.; Rabin, Douglas M. (Technical Monitor)

    2002-01-01

    Recent tends in the design, fabrication and use of High-Electron-Mobility-Transistors (HEMT) in low noise amplifiers are reviewed. Systems employing these devices have achieved the lowest system noise for wavelengths greater than three millimeters with relatively modest cryogenic cooling requirements in a variety of ground and space based applications. System requirements which arise in employing such devices in imaging applications are contrasted with other leading coherent detector candidates at microwave wavelengths. Fundamental and practical limitations which arise in the context of microwave application of field effect devices at cryogenic temperatures will be discussed from a component and systems point of view.

  14. Cryogenically Cooled Field Effect Transistors for Low-Noise Systems

    NASA Technical Reports Server (NTRS)

    Wollack, Edward J.

    2002-01-01

    Recent tends in the design, fabrication and use of High-Electron-Mobility-Transistors (HEMT) in low noise amplifiers are reviewed. Systems employing these devices have achieved the lowest system noise for wavelengths greater than three millimeters with relatively modest cryogenic cooling requirements in a variety of ground and space based applications. System requirements which arise in employing such devices in imaging applications are contrasted with other leading coherent detector candidates at microwave wavelengths. Fundamental and practical limitations which arise in the context of microwave application of field effect devices at cryogenic temperatures will be discussed from a component and systems point of view.

  15. Development of components and subsystems for low noise receivers at micro- and millimeter waves

    NASA Astrophysics Data System (ADS)

    Peltonen, Juhani K.

    1990-09-01

    The development of low noise receivers at micro- and millimeter wave frequencies mainly intended for radio astronomical studies and remote sensing applications are discussed. The work is divided into three parts: design and construction of cryogenic, low noise MESFET (Metal Semiconductor Field Effect Transistor) and HEMT (High Electron Mobility Transistor) amplifiers, studies on semiconductor local oscillators and phase locking of mm wave Gunn oscillators. The basic theory of low noise transistor amplifiers employing scattering and noise parameters of an active device is reviewed. Stability problems of amplifiers and noise measurement techniques especially applicable to cryogenic systems are discussed. Several low noise amplifiers were constructed for the frequency range of 1 to 22 GHz. As an example, a 4 GHz cryogenic MESFET IF amplifier with 20 K noise temperature was developed. A two stage coaxial HEMT amplifier with T(sub A) = 300 K at room temperature was constructed. Various designs of semiconductor local oscillators needed for mm wave receivers are reviewed. Experimental verification of the theoretical model for the waveguide mounting structure of Gunn diodes is given at frequencies of 35 to 53 GHz. Fundamental frequency local oscillators with an output power of approximately 50 mW and mechanical tuning range of 5 to 10 GHz (center frequency of 45 GHz) were constructed. Description of the phase locking scheme (exploiting bias tuning of Gunn oscillators) of the 72 to 115 GHz receiver is given. The additional factors needed in application of the basic phaselock theory to mm wave oscillators are discussed.

  16. Low-noise video amplifiers for imaging CCD's

    NASA Technical Reports Server (NTRS)

    Scinicariello, F.

    1976-01-01

    Various techniques were developed which enable the CCD (charge coupled device) imaging array user to obtain optimum performance from the device. A CCD video channel was described, and detector-preamplifier interface requirements were examined. A noise model for the system was discussed at length and laboratory data presented and compared to predicted results.

  17. Two-dimensional wind tunnel

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Information on the Japanese National Aerospace Laboratory two dimensional transonic wind tunnel, completed at the end of 1979 is presented. Its construction is discussed in detail, and the wind tunnel structure, operation, test results, and future plans are presented.

  18. Two-Dimensional IHCP Code

    Energy Science and Technology Software Center (ESTSC)

    1997-11-18

    QUENCH2D* is developed for the solution of general, non-linear, two-dimensional inverse heat transfer problems. This program provides estimates for the surface heat flux distribution and/or heat transfer coefficient as a function of time and space by using transient temperature measurements at appropriate interior points inside the quenched body. Two-dimensional planar and axisymmetric geometries such as turnbine disks and blades, clutch packs, and many other problems can be analyzed using QUENCH2D*.

  19. Nonlinearly stacked low noise turbofan stator

    NASA Technical Reports Server (NTRS)

    Schuster, William B. (Inventor); Kontos, Karen B. (Inventor); Weir, Donald S. (Inventor); Nolcheff, Nick A. (Inventor); Gunaraj, John A. (Inventor)

    2009-01-01

    A nonlinearly stacked low noise turbofan stator vane having a characteristic curve that is characterized by a nonlinear sweep and a nonlinear lean is provided. The stator is in an axial fan or compressor turbomachinery stage that is comprised of a collection of vanes whose highly three-dimensional shape is selected to reduce rotor-stator and rotor-strut interaction noise while maintaining the aerodynamic and mechanical performance of the vane. The nonlinearly stacked low noise turbofan stator vane reduces noise associated with the fan stage of turbomachinery to improve environmental compatibility.

  20. Low-Noise Spiral Bevel Gears

    NASA Technical Reports Server (NTRS)

    Lewicki, David G.; Handschuh, Robert F.; Coy, John J.; Henry, Zachary; Thomas, John; Litvin, Faydor L.

    1994-01-01

    Modified spiral bevel gears that generate relatively little noise and vibration designed and fabricated for use in U.S. Army OH-58D helicopter. Noise reduced by 12 to 19 dB. Similar low-noise, low-vibration spiral bevel gears used in other helicopters, with consequent benefits in comfort and health of pilots and passengers, enhancement of pilots' performance and safety through reduction of audible distraction, and reduction in cost and weight of helicopters through reduction in amount of sound-proofing material. Low-noise, low-vibration spiral bevel gears also used in drive axles of cars and trucks for smoother, quieter rides.

  1. Two-dimensional resonators for local oscillators

    NASA Astrophysics Data System (ADS)

    Huang, K.-c.; Jenkins, A.; Edwards, D.; Dew-Hughes, D.

    1999-11-01

    The expedited globalization of satellite technology has brought about a rapid boost in satellite competition and increased utilization of wireless communications remote data devices. In space communications receivers, there is an expanding demand for higher performance from local oscillators. The determining conditions are high Q values, high circulating power and low amplifier noise figures. In spite of their low insertion loss, conventional one-dimensional high-temperature superconducting (HTS) resonator-feedback oscillators suffer from high peak current densities inside the resonator and thus have a limited power-handling characteristics. To achieve higher-power oscillators, it is possible to introduce a two-dimensional microstrip resonator to balance the internal current distribution. To this end, 3 GHz two-dimensional resonators have been fabricated from TBCCO 2212 thin films deposited by RF sputtering onto 2 cm square LaAlO3 substrates. This paper demonstrates the frequency stabilizer role and the frequency response of the two-dimensional resonator. The considerable improvement for the performance of resonator-feedback oscillators constructed using such HTS resonators will also be presented.

  2. Low-noise macroscopic twin beams

    NASA Astrophysics Data System (ADS)

    Iskhakov, Timur Sh.; Usenko, Vladyslav C.; Filip, Radim; Chekhova, Maria V.; Leuchs, Gerd

    2016-04-01

    Applying a multiphoton-subtraction technique to the two-color macroscopic squeezed vacuum state of light generated via high-gain parametric down-conversion we conditionally prepare a different state of light: bright multimode low-noise twin beams. A lower noise in the sum of the photon numbers opens a possibility to encode information into this variable while keeping the nonclassical character of the state. The obtained results demonstrate up to eightfold suppression of noise in each beam while preserving and even moderately improving the nonclassical photon-number correlations between the beams. The prepared low-noise macroscopic state, containing up to 2000 photons per mode, is not among the Gaussian states achievable through nonlinear optical processes. Apart from that, we suggest a method for measuring quantum efficiency, which is based on the Fano factor measurement. The proposed technique substantially improves the usefulness of twin beams for quantum communication and metrology.

  3. A low noise 500 MHz frequency source

    NASA Astrophysics Data System (ADS)

    Vulcan, A.; Bloch, M.; Tanski, W.

    A low-noise signal source providing multiple 500 MHz and 400 MHz outputs is presented whose noise characteristics approach the thermal limit at frequencies spaced greater than 1 MHz from the carrier. The unit uses bulk and surface acoustic wave resonators to insure low phase noise and spurious outputs and is totally redundant for failsafe operation. The packaging concept minimizes subassembly interconnections and provides both physical and electrical independence of two redundant generators; package shielding insures minimum conducted and radiated susceptibility.

  4. The low noise limit in gene expression

    SciTech Connect

    Dar, Roy D.; Weinberger, Leor S.; Cox, Chris D.; Simpson, Michael L.; Razooky, Brandon S.

    2015-10-21

    Protein noise measurements are increasingly used to elucidate biophysical parameters. Unfortunately noise analyses are often at odds with directly measured parameters. Here we show that these inconsistencies arise from two problematic analytical choices: (i) the assumption that protein translation rate is invariant for different proteins of different abundances, which has inadvertently led to (ii) the assumption that a large constitutive extrinsic noise sets the low noise limit in gene expression. While growing evidence suggests that transcriptional bursting may set the low noise limit, variability in translational bursting has been largely ignored. We show that genome-wide systematic variation in translational efficiency can-and in the case of E. coli does-control the low noise limit in gene expression. Therefore constitutive extrinsic noise is small and only plays a role in the absence of a systematic variation in translational efficiency. Lastly, these results show the existence of two distinct expression noise patterns: (1) a global noise floor uniformly imposed on all genes by expression bursting; and (2) high noise distributed to only a select group of genes.

  5. The low noise limit in gene expression

    DOE PAGESBeta

    Dar, Roy D.; Weinberger, Leor S.; Cox, Chris D.; Simpson, Michael L.; Razooky, Brandon S.

    2015-10-21

    Protein noise measurements are increasingly used to elucidate biophysical parameters. Unfortunately noise analyses are often at odds with directly measured parameters. Here we show that these inconsistencies arise from two problematic analytical choices: (i) the assumption that protein translation rate is invariant for different proteins of different abundances, which has inadvertently led to (ii) the assumption that a large constitutive extrinsic noise sets the low noise limit in gene expression. While growing evidence suggests that transcriptional bursting may set the low noise limit, variability in translational bursting has been largely ignored. We show that genome-wide systematic variation in translational efficiencymore » can-and in the case of E. coli does-control the low noise limit in gene expression. Therefore constitutive extrinsic noise is small and only plays a role in the absence of a systematic variation in translational efficiency. Lastly, these results show the existence of two distinct expression noise patterns: (1) a global noise floor uniformly imposed on all genes by expression bursting; and (2) high noise distributed to only a select group of genes.« less

  6. The Low Noise Limit in Gene Expression

    PubMed Central

    Dar, Roy D.; Razooky, Brandon S.; Weinberger, Leor S.; Cox, Chris D.; Simpson, Michael L.

    2015-01-01

    Protein noise measurements are increasingly used to elucidate biophysical parameters. Unfortunately noise analyses are often at odds with directly measured parameters. Here we show that these inconsistencies arise from two problematic analytical choices: (i) the assumption that protein translation rate is invariant for different proteins of different abundances, which has inadvertently led to (ii) the assumption that a large constitutive extrinsic noise sets the low noise limit in gene expression. While growing evidence suggests that transcriptional bursting may set the low noise limit, variability in translational bursting has been largely ignored. We show that genome-wide systematic variation in translational efficiency can–and in the case of E. coli does–control the low noise limit in gene expression. Therefore constitutive extrinsic noise is small and only plays a role in the absence of a systematic variation in translational efficiency. These results show the existence of two distinct expression noise patterns: (1) a global noise floor uniformly imposed on all genes by expression bursting; and (2) high noise distributed to only a select group of genes. PMID:26488303

  7. Ultra-low-noise preamplifier for condenser microphones.

    PubMed

    Starecki, Tomasz

    2010-12-01

    The paper presents the design of a low-noise preamplifier dedicated for condenser measurement microphones used in high sensitivity applications, in which amplifier noise is the main factor limiting sensitivity of the measurements. In measurement microphone preamplifiers, the dominant source of noise at lower frequencies is the bias resistance of the input stage. In the presented solution, resistors were connected to the input stage by means of switches. The switches are opened during measurements, which disconnects the resistors from the input stage and results in noise reduction. Closing the switches allows for fast charging of the microphone capacitance. At low frequencies the noise of the designed preamplifier is a few times lower in comparison to similar, commercially available instruments. PMID:21198039

  8. A battery-based, low-noise voltage source

    NASA Astrophysics Data System (ADS)

    Wagner, Anke; Sturm, Sven; Schabinger, Birgit; Blaum, Klaus; Quint, Wolfgang

    2010-06-01

    A highly stable, low-noise voltage source was designed to improve the stability of the electrode bias voltages of a Penning trap. To avoid excess noise and ground loops, the voltage source is completely independent of the public electric network and uses a 12 V car battery to generate output voltages of ±15 and ±5 V. First, the dc supply voltage is converted into ac-voltage and gets amplified. Afterwards, the signal is rectified, filtered, and regulated to the desired output value. Each channel can deliver up to 1.5 A. The current as well as the battery voltage and the output voltages can be read out via a universal serial bus (USB) connection for monitoring purposes. With the presented design, a relative voltage stability of 7×10-7 over 6.5 h and a noise level equal or smaller than 30 nV/√Hz is achieved.

  9. A battery-based, low-noise voltage source.

    PubMed

    Wagner, Anke; Sturm, Sven; Schabinger, Birgit; Blaum, Klaus; Quint, Wolfgang

    2010-06-01

    A highly stable, low-noise voltage source was designed to improve the stability of the electrode bias voltages of a Penning trap. To avoid excess noise and ground loops, the voltage source is completely independent of the public electric network and uses a 12 V car battery to generate output voltages of +/-15 and +/-5 V. First, the dc supply voltage is converted into ac-voltage and gets amplified. Afterwards, the signal is rectified, filtered, and regulated to the desired output value. Each channel can deliver up to 1.5 A. The current as well as the battery voltage and the output voltages can be read out via a universal serial bus (USB) connection for monitoring purposes. With the presented design, a relative voltage stability of 7 x 10(-7) over 6.5 h and a noise level equal or smaller than 30 nV/square root(Hz) is achieved. PMID:20590260

  10. Ultra-low-noise preamplifier for condenser microphones

    NASA Astrophysics Data System (ADS)

    Starecki, Tomasz

    2010-12-01

    The paper presents the design of a low-noise preamplifier dedicated for condenser measurement microphones used in high sensitivity applications, in which amplifier noise is the main factor limiting sensitivity of the measurements. In measurement microphone preamplifiers, the dominant source of noise at lower frequencies is the bias resistance of the input stage. In the presented solution, resistors were connected to the input stage by means of switches. The switches are opened during measurements, which disconnects the resistors from the input stage and results in noise reduction. Closing the switches allows for fast charging of the microphone capacitance. At low frequencies the noise of the designed preamplifier is a few times lower in comparison to similar, commercially available instruments.

  11. Note: Broadband low-noise photodetector for Pound-Drever-Hall laser stabilization.

    PubMed

    Potnis, Shreyas; Vutha, Amar C

    2016-07-01

    The Pound-Drever-Hall laser stabilization technique requires a fast, low-noise photodetector. We present a simple photodetector design that uses a transformer as an intermediary between a photodiode and cascaded low-noise radio-frequency amplifiers. Our implementation using a silicon photodiode yields a detector with 50 MHz bandwidth, gain >10(5) V/A, and input current noise <4 pA/Hz, allowing us to obtain shot-noise-limited performance with low optical power. PMID:27475611

  12. Two-dimensional thermofield bosonization

    SciTech Connect

    Amaral, R.L.P.G.

    2005-12-15

    The main objective of this paper was to obtain an operator realization for the bosonization of fermions in 1 + 1 dimensions, at finite, non-zero temperature T. This is achieved in the framework of the real-time formalism of Thermofield Dynamics. Formally, the results parallel those of the T = 0 case. The well-known two-dimensional Fermion-Boson correspondences at zero temperature are shown to hold also at finite temperature. To emphasize the usefulness of the operator realization for handling a large class of two-dimensional quantum field-theoretic problems, we contrast this global approach with the cumbersome calculation of the fermion-current two-point function in the imaginary-time formalism and real-time formalisms. The calculations also illustrate the very different ways in which the transmutation from Fermi-Dirac to Bose-Einstein statistics is realized.

  13. Two-dimensional NMR spectrometry

    SciTech Connect

    Farrar, T.C.

    1987-06-01

    This article is the second in a two-part series. In part one (ANALYTICAL CHEMISTRY, May 15) the authors discussed one-dimensional nuclear magnetic resonance (NMR) spectra and some relatively advanced nuclear spin gymnastics experiments that provide a capability for selective sensitivity enhancements. In this article and overview and some applications of two-dimensional NMR experiments are presented. These powerful experiments are important complements to the one-dimensional experiments. As in the more sophisticated one-dimensional experiments, the two-dimensional experiments involve three distinct time periods: a preparation period, t/sub 0/; an evolution period, t/sub 1/; and a detection period, t/sub 2/.

  14. Two dimensional unstable scar statistics.

    SciTech Connect

    Warne, Larry Kevin; Jorgenson, Roy Eberhardt; Kotulski, Joseph Daniel; Lee, Kelvin S. H. (ITT Industries/AES Los Angeles, CA)

    2006-12-01

    This report examines the localization of time harmonic high frequency modal fields in two dimensional cavities along periodic paths between opposing sides of the cavity. The cases where these orbits lead to unstable localized modes are known as scars. This paper examines the enhancements for these unstable orbits when the opposing mirrors are both convex and concave. In the latter case the construction includes the treatment of interior foci.

  15. Hybrid matrix amplifier

    DOEpatents

    Martens, J.S.; Hietala, V.M.; Plut, T.A.

    1995-01-03

    The present invention comprises a novel matrix amplifier. The matrix amplifier includes an active superconducting power divider (ASPD) having N output ports; N distributed amplifiers each operatively connected to one of the N output ports of the ASPD; and a power combiner having N input ports each operatively connected to one of the N distributed amplifiers. The distributed amplifier can included M stages of amplification by cascading superconducting active devices. The power combiner can include N active elements. The resulting (N[times]M) matrix amplifier can produce signals of high output power, large bandwidth, and low noise. 6 figures.

  16. Hybrid matrix amplifier

    DOEpatents

    Martens, Jon S.; Hietala, Vincent M.; Plut, Thomas A.

    1995-01-01

    The present invention comprises a novel matrix amplifier. The matrix amplifier includes an active superconducting power divider (ASPD) having N output ports; N distributed amplifiers each operatively connected to one of the N output ports of the ASPD; and a power combiner having N input ports each operatively connected to one of the N distributed amplifiers. The distributed amplifier can included M stages of amplification by cascading superconducting active devices. The power combiner can include N active elements. The resulting (N.times.M) matrix amplifier can produce signals of high output power, large bandwidth, and low noise.

  17. A LOW NOISE RF SOURCE FOR RHIC.

    SciTech Connect

    HAYES,T.

    2004-07-05

    The Relativistic Heavy Ion Collider (RHIC) requires a low noise rf source to ensure that beam lifetime during a store is not limited by the rf system. The beam is particularly sensitive to noise from power line harmonics. Additionally, the rf source must be flexible enough to handle the frequency jump required for rebucketing (transferring bunches from the acceleration to the storage rf systems). This paper will describe the design of a Direct Digital Synthesizer (DDS) based system that provides both the noise performance and the flexibility required.

  18. Amplifier arrays for CMB polarization

    NASA Technical Reports Server (NTRS)

    Gaier, Todd; Lawrence, Charles R.; Seiffert, Michael D.; Wells, Mary M.; Kangaslahti, Pekka; Dawson, Douglas

    2003-01-01

    Cryogenic low noise amplifier technology has been successfully used in the study of the cosmic microwave background (CMB). MMIC (Monolithic Millimeter wave Integrated Circuit) technology makes the mass production of coherent detection receivers feasible.

  19. Two-dimensional colloidal alloys.

    PubMed

    Law, Adam D; Buzza, D Martin A; Horozov, Tommy S

    2011-03-25

    We study the structure of mixed monolayers of large (3 μm diameter) and small (1 μm diameter) very hydrophobic silica particles at an octane-water interface as a function of the number fraction of small particles ξ. We find that a rich variety of two-dimensional hexagonal super-lattices of large (A) and small (B) particles can be obtained in this system due to strong and long-range electrostatic repulsions through the nonpolar octane phase. The structures obtained for the different compositions are in good agreement with zero temperature calculations and finite temperature computer simulations. PMID:21517357

  20. Two-Dimensional Colloidal Alloys

    NASA Astrophysics Data System (ADS)

    Law, Adam D.; Buzza, D. Martin A.; Horozov, Tommy S.

    2011-03-01

    We study the structure of mixed monolayers of large (3μm diameter) and small (1μm diameter) very hydrophobic silica particles at an octane-water interface as a function of the number fraction of small particles ξ. We find that a rich variety of two-dimensional hexagonal super-lattices of large (A) and small (B) particles can be obtained in this system due to strong and long-range electrostatic repulsions through the nonpolar octane phase. The structures obtained for the different compositions are in good agreement with zero temperature calculations and finite temperature computer simulations.

  1. European low-noise MMIC technologies for cryogenic millimetre wave radio astronomical applications

    NASA Astrophysics Data System (ADS)

    Cremonini, Andrea; Mariotti, Sergio; Valenziano, Luca

    2012-09-01

    The Low Noise technology has a paramount relevance on radiotelescopes and radiometers performances. Its influence on sensitivity and temporal stability has a deep impact on obtainable scientific results. As well known, front end active part of scientific instruments are cryocooled in order to drastically reduce the intrinsic thermal noise generated by its electronic parts and consequently increase the sensitivity. In this paper we will describe the obtained results by an Italian Space Agency funded activity. The aim is to validate European MMIC Low Noise technologies and designs for cryogenic environments in the range of millimetre wave. As active device, HEMT (High Electron Mobility Transistor) are considered the best device for high frequency and low noise cryo applications. But not all the semiconductor foundry process are suitable for applications in such environment. Two European Foundries has been selected and two different HEMT based Low Noise Amplifiers have been designed and produced. The main goal of this activity is identify an European technology basement for space and ground based low noise cryogenic applications. Designs, layout, architectures, foundry processes and results will be compared.

  2. Two-dimensional separated flows

    NASA Astrophysics Data System (ADS)

    Gersten, K.

    The state of the art of asymptotic theory is discussed with respect to incompressible two-dimensional separated flows. As an example, the flow over an indented flat plate is considered for two cases: a small separation bubble within the lower part of the boundary layer, and the 'catastrophic' separation of the whole boundary layer with a large recirculating eddy. Separation means failure of Prandtl's boundary layer theory, and alternate theories are required. An example of this is shown in the calculation of circulation in the dent according to triple-deck theory. The free-streamline theory approach is used to examine the indented flat plate and the flow past a circular cylinder. Attention is also given to flow control by continuous injection, combined forced and free convection, unsteady laminar flows, and laminar flows.

  3. Two-dimensional NMR spectroscopy

    SciTech Connect

    Croasmun, W.R.; Carlson, R.M.K.

    1987-01-01

    Written for chemists and biochemists who are not NMR spectroscopists, but who wish to use the new techniques of two-dimensional NMR spectroscopy, this book brings together for the first time much of the practical and experimental data needed. It also serves as information source for industrial, academic, and graduate student researchers who already use NMR spectroscopy, but not yet in two dimensions. The authors describe the use of 2-D NMR in a wide variety of chemical and biochemical fields, among them peptides, steroids, oligo- and poly-saccharides, nucleic acids, natural products (including terpenoids, alkaloids, and coal-derived heterocyclics), and organic synthetic intermediates. They consider throughout the book both the advantages and limitations of using 2-D NMR.

  4. Low-noise fan exit guide vanes

    NASA Technical Reports Server (NTRS)

    Jones, Michael G. (Inventor); Parrott, Tony L. (Inventor); Heidelberg, Laurence J. (Inventor); Envia, Edmane (Inventor)

    2008-01-01

    Low-noise fan exit guide vanes are disclosed. According to the present invention a fan exit guide vane has an outer shell substantially shaped as an airfoil and defining an interior cavity. A porous portion of the outer shell allows communication between the fluctuations in the air passing over the guide vane and the interior cavity. At least one acoustically resonant chamber is located within the interior cavity. The resonant chamber is in communication with the porous portion of the outer perimeter. The resonant chamber is configured to reduce the noise generated at a predetermined frequency. In various preferred embodiments, there is a plurality of acoustically resonant chambers located within the interior cavity. The resonant chambers can be separated by one or more partitions within the interior cavity. In these embodiments, the resonant chambers can be configured to reduce the noise generated over a range of predetermined frequencies.

  5. Low noise and conductively cooled microchannel plates

    NASA Technical Reports Server (NTRS)

    Feller, W. B.

    1990-01-01

    Microchannel plate (MCP) dynamic range has recently been enhanced for both very low and very high input flux conditions. Improvements in MCP manufacturing technology reported earlier have led to MCPs with substantially reduced radioisotope levels, giving dramatically lower internal background-counting rates. An update is given on the Galileo low noise MCP. Also, new results in increasing the MCP linear counting range for high input flux densities are presented. By bonding the active face of a very low resistance MCP (less than 1 megaohm) to a substrate providing a conductive path for heat transport, the bias current limit (hence, MCP output count rate limit) can be increased up to two orders of magnitude. Normal pulse-counting MCP operation was observed at bias currents of several mA when a curved-channel MCP (80:1) was bonded to a ceramic multianode substrate; the MCP temperature rise above ambient was less than 40 C.

  6. Low Noise Borehole Triaxial Seismometer Phase II

    SciTech Connect

    Kerr, James D; McClung, David W

    2006-11-06

    This report describes the preliminary design and the effort to date of Phase II of a Low Noise Borehole Triaxial Seismometer for use in networks of seismic stations for monitoring underground nuclear explosions. The design uses the latest technology of broadband seismic instrumentation. Each parameter of the seismometer is defined in terms of the known physical limits of the parameter. These limits are defined by the commercially available components, and the physical size constraints. A theoretical design is proposed, and a preliminary prototype model of the proposed instrument has been built. This prototype used the sensor module of the KS2000. The installation equipment (hole locks, etc.) has been designed and one unit has been installed in a borehole. The final design of the sensors and electronics and leveling mechanism is in process. Noise testing is scheduled for the last quarter of 2006.

  7. Developing Low-Noise GaAs JFETs For Cryogenic Operation

    NASA Technical Reports Server (NTRS)

    Cunningham, Thomas J.

    1995-01-01

    Report discusses aspects of effort to develop low-noise, low-gate-leakage gallium arsenide-based junction field-effect transistors (JFETs) for operation at temperature of about 4 K as readout amplifiers and multiplexing devices for infrared-imaging devices. Transistors needed to replace silicon transistors, relatively noisy at 4 K. Report briefly discusses basic physical principles of JFETs and describes continuing process of optimization of designs of GaAs JFETs for cryogenic operation.

  8. Digital Filters for Two-Dimensional Data

    NASA Technical Reports Server (NTRS)

    Edwards, T. R.

    1983-01-01

    Computational efficient filters speed processing of two-dimensional experimental data. Two-dimensional smoothing filter used to attenuate highfrequency noise in two-dimensional numerical data arrays. Filter provides smoothed data values equal to values obtained by fitting surface with secondand third-order terms to 5 by 5 subset of data points centered on points and replacing data at each point by value of surface fitted at point. Especially suited for efficient analysis of two-dimensional experimental data on images.

  9. Development of an ultra low noise, miniature signal conditioning device for vestibular evoked response recordings

    PubMed Central

    2014-01-01

    Background Inner ear evoked potentials are small amplitude (<1 μVpk) signals that require a low noise signal acquisition protocol for successful extraction; an existing such technique is Electrocochleography (ECOG). A novel variant of ECOG called Electrovestibulography (EVestG) is currently investigated by our group, which captures vestibular responses to a whole body tilt. The objective is to design and implement a bio-signal amplifier optimized for ECOG and EVestG, which will be superior in noise performance compared to low noise, general purpose devices available commercially. Method A high gain configuration is required (>85 dB) for such small signal recordings; thus, background power line interference (PLI) can have adverse effects. Active electrode shielding and driven-right-leg circuitry optimized for EVestG/ECOG recordings were investigated for PLI suppression. A parallel pre-amplifier design approach was investigated to realize low voltage, and current noise figures for the bio-signal amplifier. Results In comparison to the currently used device, PLI is significantly suppressed by the designed prototype (by >20 dB in specific test scenarios), and the prototype amplifier generated noise was measured to be 4.8 nV/Hz @ 1 kHz (0.45 μVRMS with bandwidth 10 Hz-10 kHz), which is lower than the currently used device generated noise of 7.8 nV/Hz @ 1 kHz (0.76 μVRMS). A low noise (<1 nV/Hz) radio frequency interference filter was realized to minimize noise contribution from the pre-amplifier, while maintaining the required bandwidth in high impedance measurements. Validation of the prototype device was conducted for actual ECOG recordings on humans that showed an increase (p < 0.05) of ~5 dB in Signal-to-Noise ratio (SNR), and for EVestG recordings using a synthetic ear model that showed a ~4% improvement (p < 0.01) over the currently used amplifier. Conclusion This paper presents the design and evaluation of an ultra-low noise and miniaturized bio

  10. A gimbaled low noise momentum wheel

    NASA Technical Reports Server (NTRS)

    Bichler, U.; Eckardt, T.

    1993-01-01

    The bus actuators are the heart and at the same time the Achilles' heel of accurate spacecraft stabilization systems, because both their performance and their perturbations can have a deciding influence on the achievable pointing accuracy of the mission. The main task of the attitude actuators, which are mostly wheels, is the generation of useful torques with sufficiently high bandwidth, resolution and accuracy. This is because the bandwidth of the whole attitude control loop and its disturbance rejection capability is dependent upon these factors. These useful torques shall be provided, without - as far as possible - parasitic noise like unbalance forces and torques and harmonics. This is because such variable frequency perturbations excite structural resonances which in turn disturb the operation of sensors and scientific instruments. High accuracy spacecraft will further require bus actuators for the three linear degrees of freedom (DOF) to damp structural oscillations excited by various sources. These actuators have to cover the dynamic range of these disturbances. Another interesting feature, which is not necessarily related to low noise performance, is a gimballing capability which enables, in a certain angular range, a three axis attitude control with only one wheel. The herein presented Teldix MWX, a five degree of freedom Magnetic Bearing Momentum Wheel, incorporates all the above required features. It is ideally suited to support, as a gyroscopic actuator in the attitude control system, all High Pointing Accuracy and Vibration Sensitive space missions.

  11. Low Noise Exhaust Nozzle Technology Development

    NASA Technical Reports Server (NTRS)

    Majjigi, R. K.; Balan, C.; Mengle, V.; Brausch, J. F.; Shin, H.; Askew, J. W.

    2005-01-01

    NASA and the U.S. aerospace industry have been assessing the economic viability and environmental acceptability of a second-generation supersonic civil transport, or High Speed Civil Transport (HSCT). Development of a propulsion system that satisfies strict airport noise regulations and provides high levels of cruise and transonic performance with adequate takeoff performance, at an acceptable weight, is critical to the success of any HSCT program. The principal objectives were to: 1. Develop a preliminary design of an innovative 2-D exhaust nozzle with the goal of meeting FAR36 Stage III noise levels and providing high levels of cruise performance with a high specific thrust for Mach 2.4 HSCT with a range of 5000 nmi and a payload of 51,900 lbm, 2. Employ advanced acoustic and aerodynamic codes during preliminary design, 3. Develop a comprehensive acoustic and aerodynamic database through scale-model testing of low-noise, high-performance, 2-D nozzle configurations, based on the preliminary design, and 4. Verify acoustic and aerodynamic predictions by means of scale-model testing. The results were: 1. The preliminary design of a 2-D, convergent/divergent suppressor ejector nozzle for a variable-cycle engine powered, Mach 2.4 HSCT was evolved, 2. Noise goals were predicted to be achievable for three takeoff scenarios, and 3. Impact of noise suppression, nozzle aerodynamic performance, and nozzle weight on HSCT takeoff gross weight were assessed.

  12. A gimbaled low noise momentum wheel

    NASA Astrophysics Data System (ADS)

    Bichler, U.; Eckardt, T.

    1993-05-01

    The bus actuators are the heart and at the same time the Achilles' heel of accurate spacecraft stabilization systems, because both their performance and their perturbations can have a deciding influence on the achievable pointing accuracy of the mission. The main task of the attitude actuators, which are mostly wheels, is the generation of useful torques with sufficiently high bandwidth, resolution and accuracy. This is because the bandwidth of the whole attitude control loop and its disturbance rejection capability is dependent upon these factors. These useful torques shall be provided, without - as far as possible - parasitic noise like unbalance forces and torques and harmonics. This is because such variable frequency perturbations excite structural resonances which in turn disturb the operation of sensors and scientific instruments. High accuracy spacecraft will further require bus actuators for the three linear degrees of freedom (DOF) to damp structural oscillations excited by various sources. These actuators have to cover the dynamic range of these disturbances. Another interesting feature, which is not necessarily related to low noise performance, is a gimballing capability which enables, in a certain angular range, a three axis attitude control with only one wheel. The herein presented Teldix MWX, a five degree of freedom Magnetic Bearing Momentum Wheel, incorporates all the above required features. It is ideally suited to support, as a gyroscopic actuator in the attitude control system, all High Pointing Accuracy and Vibration Sensitive space missions.

  13. Forward sweep, low noise rotor blade

    NASA Technical Reports Server (NTRS)

    Brooks, Thomas F. (Inventor)

    1996-01-01

    A forward-swept, low-noise rotor blade includes an inboard section, an aft-swept section and a forward-swept outboard section. The rotor blade reduces the noise of rotorcraft, including both standard helicopters and advanced systems such as tiltrotors. The primary noise reduction feature is the forward sweep of the planform over a large portion of the outer blade radius. The rotor blade also includes an aft-swept section. The purpose of the aft-swept region is to provide a partial balance to pitching moments produced by the outboard forward-swept portion of the blade. The rotor blade has a constant chord width; or has a chord width which decreases linearly along the entire blade span; or combines constant and decreasing chord widths, wherein the blade is of constant chord width from the blade root to a certain location on the rotor blade, then decreases linearly to the blade tip thereafter. The noise source showing maximum noise reduction is blade-vortex interaction (BVI) noise. Also reduced are thickness, noise, high speed impulsive noise, cabin vibration and loading noise.

  14. A low-noise beta-radiometer

    SciTech Connect

    Antonenko, G.I.; Savina, V.I.

    1995-12-01

    The two-channel detector for a low-noise (down to 0.06 sec{sup -1}) beta-radiometer for measuring the mass concentration of {sup 90}Sr in the environment after the chemical extraction of strontium by the oxalate-nitrate method was certified at the D.I. Mendeleev Institute of Metrology (certificate No. 137/93). A detector unit using two end-window self-quenching counters with thin input windows (8 {mu}m thick and 60 mm in diameter) operating as a Geiger-Mueller counter and filled with a mixture of 90% helium (atomic gas) and 10% ethanol (organic molecules) can measure the beta-activity of two substrates concurrently. It is often used to detect the beta-radiation of {sup 90}Sr. This isotope produces particles with energies ranging from 180 to 1000 keV, and the detection efficiency is 50% at a level of 0.1 Bq after measuring for 20 min with an uncertainty of 25%.

  15. A Low-Noise, Wideband Preamplifier for a Fourier-Transform Ion Cyclotron Resonance Mass Spectrometer

    PubMed Central

    Mathur, Raman; Knepper, Ronald W.; O'Connor, Peter B.

    2009-01-01

    FTMS performance parameters such as limits of detection, dynamic range, sensitivity, and even mass accuracy and resolution can be greatly improved by enhancing its detection circuit. An extended investigation of significant design considerations for optimal signal-to-noise ratio in an FTMS detection circuit are presented. A low noise amplifier for an FTMS is developed based on the discussed design rules. The amplifier has a gain of ≈ 3500 and a bandwidth of 10 kHz - 1 MHz corresponding to m/z range of 100 Da to 10 kDa (at 7 Tesla). The performance of the amplifier was tested on a MALDI-FTMS, and has demonstrated a 25-fold reduction in noise in a mass spectrum of C60 compared to that of a commercial amplifier. PMID:18029195

  16. Ultra-Low Noise HEMT Device Models: Application of On-Wafer Cryogenic Noise Analysis and Improved Parameter Extraction Techniques

    NASA Technical Reports Server (NTRS)

    Bautista, J. J.; Hamai, M.; Nishimoto, M.; Laskar, J.; Szydlik, P.; Lai, R.

    1995-01-01

    Significant advances in the development of HEMT technology have resulted in high performance cryogenic low noise amplifiers whose noise temperatures are within an order of magnitude of the quantum noise limit. Key to the identification of optimum HEMT structures at cryogenic temperatures is the development of on-wafer noise and device parameter extraction techniques. Techniques and results are described.

  17. Low Noise Research Fan Stage Design

    NASA Technical Reports Server (NTRS)

    Hobbs, David E.; Neubert, Robert J.; Malmborg, Eric W.; Philbrick, Daniel H.; Spear, David A.

    1995-01-01

    This report describes the design of a Low Noise ADP Research Fan stage. The fan is a variable pitch design which is designed at the cruise pitch condition. Relative to the cruise setting, the blade is closed at takeoff and opened for reverse thrust operation. The fan stage is a split flow design with fan exit guide vanes and core stators. This fan stage design was combined with a nacelle and engine core duct to form a powered fan/nacelle, subscale model. This model is intended for use in aerodynamic performance, acoustic and structural testing in a wind tunnel. The model has a 22-inch outer fan diameter and a hub-to-top ratio of 0.426 which permits the use of existing NASA fan and cowl force balance designs and rig drive system. The design parameters were selected to permit valid acoustic and aerodynamic comparisons with the PW 17-inch rig previously tested under NASA contract. The fan stage design is described in detail. The results of the design axisymmetric analysis at aerodynamic design condition are included. The structural analysis of the fan rotor and attachment is described including the material selections and stress analysis. The blade and attachment are predicted to have adequate low cycle fatigue life, and an acceptable operating range without resonant stress or flutter. The stage was acoustically designed with airfoil counts in the fan exit guide vane and core stator to minimize noise. A fan-FEGV tone analysis developed separately under NASA contract was used to determine these airfoil counts. The fan stage design was matched to a nacelle design to form a fan/nacelle model for wind tunnel testing. The nacelle design was developed under a separate NASA contract. The nacelle was designed with an axisymmetric inlet, cowl and nozzle for convenience in testing and fabrication. Aerodynamic analysis of the nacelle confirmed the required performance at various aircraft operating conditions.

  18. A 65-nm low-noise low-cost ΣΔ modulator for audio applications

    NASA Astrophysics Data System (ADS)

    Guo, Liang; Lu, Liao; Hao, Luo; Xiaopeng, Liu; Xiaoxia, Han; Yan, Han

    2012-02-01

    This paper introduces a low-noise low-cost ΣΔ modulator for digital audio analog-to-digital conversion. By adopting a low-noise large-output swing operation amplifier, not only is the flicker noise greatly inhibited, but also the power consumption is reduced. Also the area cost is relatively small. The modulator was implemented in a SMIC standard 65-nm CMOS process. Measurement results show it can achieve 96 dB peak signal-to-noise plus distortion ratio (SNDR) and 105 dB dynamic range (DR) over the 22.05-kHz audio band and occupies 0.16 mm2. The power consumption of the proposed modulator is 4.9 mW from a 2.5 V power supply, which is suitable for high-performance, low-cost audio codec applications.

  19. Low-noise hybrid superconductor/semiconductor 7.4 GHz receiver downconverter for NASA space applications

    SciTech Connect

    Javadi, H.H.S.; Barner, J.B.; Bautista, J.J.

    1994-12-31

    A low-noise microwave receiver downconverter utilizing thin-film high-critical-temperature superconducting (HTS) passive circuitry and semiconductor active devices has been developed for use in space. It consists of an HTS preselect filter, a cryogenic low-noise amplifier, a cryogenic mixer, and a cryogenic oscillator with an HTS resonator. The downconverter converts a 200 MHz wide band centered around 7.35 GHz to a band centered around 1.0 GHz. When cooled to 77 K, the downconverter plus cables inside a cryogenic refrigerator produced a noise temperature measured at the refrigerator port of approximately 50 K with conversion gain of 18 dB.

  20. Measuring Monotony in Two-Dimensional Samples

    ERIC Educational Resources Information Center

    Kachapova, Farida; Kachapov, Ilias

    2010-01-01

    This note introduces a monotony coefficient as a new measure of the monotone dependence in a two-dimensional sample. Some properties of this measure are derived. In particular, it is shown that the absolute value of the monotony coefficient for a two-dimensional sample is between /"r"/ and 1, where "r" is the Pearson's correlation coefficient for…

  1. Two Dimensional Mechanism for Insect Hovering

    SciTech Connect

    Jane Wang, Z.

    2000-09-04

    Resolved computation of two dimensional insect hovering shows for the first time that a two dimensional hovering motion can generate enough lift to support a typical insect weight. The computation reveals a two dimensional mechanism of creating a downward dipole jet of counterrotating vortices, which are formed from leading and trailing edge vortices. The vortex dynamics further elucidates the role of the phase relation between the wing translation and rotation in lift generation and explains why the instantaneous forces can reach a periodic state after only a few strokes. The model predicts the lower limits in Reynolds number and amplitude above which the averaged forces are sufficient. (c) 2000 The American Physical Society.

  2. Compact low-noise preamplifier for noise spectroscopy with biased photodiodes in cargo inspection systems

    NASA Astrophysics Data System (ADS)

    Benetti, Bob; Langeveld, Willem G. J.

    2013-09-01

    Noise Spectroscopy, a.k.a. Z-determination by Statistical Count-rate ANalysis (Z-SCAN), is a statistical technique to determine a quantity called the "noise figure" from digitized waveforms of pulses of transmitted x-rays in cargo inspection systems. Depending only on quantities related to the x-ray energies, it measures a characteristic of the transmitted x-ray spectrum, which depends on the atomic number, Z, of the material penetrated. The noise figure can thus be used for material separation. In an 80-detector prototype, scintillators are used with large-area photodiodes biased at 80V and digitized using 50-MSPS 12-bit ADC boards. We present an ultra-compact low-noise preamplifier design, with one high-gain and one low-gain channel per detector for improved dynamic range. To achieve adequate detection sensitivity and spatial resolution each dual-gain preamplifier channel must fit within a 12.7 mm wide circuit board footprint and maintain adequate noise immunity to conducted and radiated interference from adjacent channels. The novel design included iterative SPICE analysis of transient response, dynamic range, frequency response, and noise analysis to optimize the selection and configuration of amplifiers and filter response. We discuss low-noise active and passive components and low-noise techniques for circuit board layout that are essential to achieving the design goals, and how the completed circuit board performed in comparison to the predicted responses.

  3. Two-dimensional order and disorder thermofields

    SciTech Connect

    Belvedere, L. V.

    2006-11-15

    The main objective of this paper was to obtain the two-dimensional order and disorder thermal operators using the Thermofield Bosonization formalism. We show that the general property of the two-dimensional world according with the bosonized Fermi field at zero temperature can be constructed as a product of an order and a disorder variables which satisfy a dual field algebra holds at finite temperature. The general correlation functions of the order and disorder thermofields are obtained.

  4. Efficient Two-Dimensional-FFT Program

    NASA Technical Reports Server (NTRS)

    Miko, J.

    1992-01-01

    Program computes 64 X 64-point fast Fourier transform in less than 17 microseconds. Optimized 64 X 64 Point Two-Dimensional Fast Fourier Transform combines performance of real- and complex-valued one-dimensional fast Fourier transforms (FFT's) to execute two-dimensional FFT and coefficients of power spectrum. Coefficients used in many applications, including analyzing spectra, convolution, digital filtering, processing images, and compressing data. Source code written in C, 8086 Assembly, and Texas Instruments TMS320C30 Assembly languages.

  5. A low-noise large dynamic-range readout suitable for laser spectroscopy with photodiodes

    NASA Astrophysics Data System (ADS)

    Pullia, A.; Sanvito, T.; Potenza, M. A.; Zocca, F.

    2012-10-01

    An original low-noise large dynamic-range readout system for optical light spectroscopy with PIN diodes is presented. The front-end circuit is equipped with a smart device for automatic cancellation of the large dc offset brought about by the photodiode current. This device sinks away the exact amount of dc current from the preamplifier input, yielding auto zeroing of the output-voltage offset, while introducing the minimum electronic noise possible. As a result the measurement dynamic-range is maximized. Moreover, an auxiliary inspection point is provided which precisely tracks the dc component of the photodiode current. This output allows for precise beam alignment and may also be used for diagnostic purposes. The excellent gain stability and linearity make the circuit perfectly suited for optical-light pulse spectroscopy. Applications include particle sizing in the 100 nm range, two-dimensional characterization of semiconductor detectors, ultra-precise characterization of laser beam stability, confocal microscopy.

  6. Very Low Noise Multiplexing with SQUIDs and SiGe Heterojunction Bipolar Transistors for Readout of Large Superconducting Bolometer Arrays

    NASA Astrophysics Data System (ADS)

    Voisin, F.; Bréelle, E.; Piat, M.; Prêle, D.; Klisnick, G.; Sou, G.; Redon, M.

    2008-05-01

    This paper presents an ultra low noise instrumentation based on a standard BiCMOS SiGe 0.35 μm ASIC operating at cryogenic temperatures. The main functions of the electronic circuit are the readout and the multiplexing of SQUIDs/TES. We report the cryogenic operation of the ASIC dedicated to the readout of a 2×4 pixel demonstrator array. We particularly emphasize on the development and the test phases of an ultra low noise ( 0.2 nV/sqrt{Hz} ) cryogenic amplifier designed with two multiplexed inputs. The cryogenic SiGe amplifier coupled to a SQUID in a FLL operating at 4.2 K is also presented.

  7. Very-low-noise multiplexing with SQUIDs and SiGe HBTs for readout of large superconducting bolometer arrays

    NASA Astrophysics Data System (ADS)

    Prêle, D.; Klisnick, G.; Sou, G.; Redon, M.; Bréelle, E.; Voisin, F.; Piat, M.

    2007-08-01

    We present an ultra-low-noise instrumentation based on a standard BiCMOS SiGe 0.35 μm ASIC operating at cryogenic temperatures. The main functions of the electronic circuit are the readout and the multiplexing of SQUIDs/TES arrays. We report the cryogenic operation of the ASIC dedicated to the readout of a 2×4 pixel demonstrator array. We particularly emphasise on the development, and the test phases of an ultra-low-noise (0.2 nV/√Hz) cryogenic amplifier designed with two multiplexed input. The cryogenic SiGe amplifier coupled to a SQUID in a FLL operating at 4.2 K is also presented.

  8. Low-noise preamplifier based on PMT and its signal processing

    NASA Astrophysics Data System (ADS)

    Ye, Li-hua; Wang, Hai-yang; Wang, Wen-xuan; Cui, Yi-ping; Hang, Jian-jun; Sha, Tao

    2013-09-01

    Through the establishment of the noise model for photomultiplier, estimate the signal-to-noise ratio of the photomultiplier tube, using the principle of photoelectric detection technology, combined with the needs of practical applications; select the appropriate photoelectric multiplier tube, from the two aspects of the dynamic design and static design to ensure the correct output signal of the photomultiplier tube. The low noise preamplifier will amplify the output signal of photomultiplier tube without noise as soon as possible. This article describes the design principles of the photomultiplier tube selection and application. From the op-amp selection, multistage amplifier circuit design, circuit noise estimation, PCB board layout line and shielding, proposed a practical circuit design of 10MHz band width; and matters needing attention and its signal processing method. The simulation results show that the signal amplifying circuit designed, this circuit design can be very well amplifying and processing the output signal of the photomultiplier tube. To verify the theory of articles derived from circuit simulation to the actual test. Simulation results show that the signal amplifying circuit design, this form of circuit design can be very good enlarged and processing the output signal of the photomultiplier tube. From the actual test, the test results show that the accuracy and practicality of the simulation results.

  9. Electrical contacts to two-dimensional semiconductors.

    PubMed

    Allain, Adrien; Kang, Jiahao; Banerjee, Kaustav; Kis, Andras

    2015-12-01

    The performance of electronic and optoelectronic devices based on two-dimensional layered crystals, including graphene, semiconductors of the transition metal dichalcogenide family such as molybdenum disulphide (MoS2) and tungsten diselenide (WSe2), as well as other emerging two-dimensional semiconductors such as atomically thin black phosphorus, is significantly affected by the electrical contacts that connect these materials with external circuitry. Here, we present a comprehensive treatment of the physics of such interfaces at the contact region and discuss recent progress towards realizing optimal contacts for two-dimensional materials. We also discuss the requirements that must be fulfilled to realize efficient spin injection in transition metal dichalcogenides. PMID:26585088

  10. Crossflow in two-dimensional asymmetric nozzles

    NASA Technical Reports Server (NTRS)

    Sebacher, D. I.; Lee, L. P.

    1975-01-01

    An experimental investigation of the crossflow effects in three contoured, two-dimensional asymmetric nozzles is described. The data were compared with theoretical predictions of nozzle flow by using an inviscid method of characteristics solution and two-dimensional turbulent boundary-layer calculations. The effect of crossflow as a function of the nozzle maximum expansion angle was studied by use of oil-flow techniques, static wall-pressure measurements, and impact-pressure surveys at the nozzle exit. Reynolds number effects on crossflow were investigated.

  11. Two-dimensional nanolithography using atom interferometry

    SciTech Connect

    Gangat, A.; Pradhan, P.; Pati, G.; Shahriar, M.S.

    2005-04-01

    We propose a scheme for the lithography of arbitrary, two-dimensional nanostructures via matter-wave interference. The required quantum control is provided by a {pi}/2-{pi}-{pi}/2 atom interferometer with an integrated atom lens system. The lens system is developed such that it allows simultaneous control over the atomic wave-packet spatial extent, trajectory, and phase signature. We demonstrate arbitrary pattern formations with two-dimensional {sup 87}Rb wave packets through numerical simulations of the scheme in a practical parameter space. Prospects for experimental realizations of the lithography scheme are also discussed.

  12. A programmable ultra-low noise X-band exciter.

    PubMed

    MacMullen, A; Hoover, L R; Justice, R D; Callahan, B S

    2001-07-01

    A programmable ultra-low noise X-band exciter has been developed using commercial off-the-shelf components. Its phase noise is more than 10 dB below the best available microwave synthesizers. It covers a 7% frequency band with 0.1-Hz resolution. The X-band output at +23 dBm is a combination of signals from an X-band sapphire-loaded cavity oscillator (SLCO), a low noise UHF frequency synthesizer, and special-purpose frequency translation and up-conversion circuitry. PMID:11477765

  13. On the design and test of a low noise propeller

    NASA Technical Reports Server (NTRS)

    Succi, G. P.

    1981-01-01

    An extensive review of noise and performance of general aviation propellers was performed. Research was done in three areas: The acoustic and aerodynamic theory of general aviation propellers, wind tunnel tests of three one-quarter scale models of general aviation propellers, and flight test of two low noise propellers. The design and testing of the second propeller is reviewed. The general aerodynamic considerations needed to design a new propeller are described. The design point analysis of low noise propellers is reviewed. The predicted and measured noise levels are compared.

  14. Two-Dimensional Motions of Rockets

    ERIC Educational Resources Information Center

    Kang, Yoonhwan; Bae, Saebyok

    2007-01-01

    We analyse the two-dimensional motions of the rockets for various types of rocket thrusts, the air friction and the gravitation by using a suitable representation of the rocket equation and the numerical calculation. The slope shapes of the rocket trajectories are discussed for the three types of rocket engines. Unlike the projectile motions, the…

  15. Nitrogenated holey two-dimensional structures

    PubMed Central

    Mahmood, Javeed; Lee, Eun Kwang; Jung, Minbok; Shin, Dongbin; Jeon, In-Yup; Jung, Sun-Min; Choi, Hyun-Jung; Seo, Jeong-Min; Bae, Seo-Yoon; Sohn, So-Dam; Park, Noejung; Oh, Joon Hak; Shin, Hyung-Joon; Baek, Jong-Beom

    2015-01-01

    Recent graphene research has triggered enormous interest in new two-dimensional ordered crystals constructed by the inclusion of elements other than carbon for bandgap opening. The design of new multifunctional two-dimensional materials with proper bandgap has become an important challenge. Here we report a layered two-dimensional network structure that possesses evenly distributed holes and nitrogen atoms and a C2N stoichiometry in its basal plane. The two-dimensional structure can be efficiently synthesized via a simple wet-chemical reaction and confirmed with various characterization techniques, including scanning tunnelling microscopy. Furthermore, a field-effect transistor device fabricated using the material exhibits an on/off ratio of 107, with calculated and experimental bandgaps of approximately 1.70 and 1.96 eV, respectively. In view of the simplicity of the production method and the advantages of the solution processability, the C2N-h2D crystal has potential for use in practical applications. PMID:25744355

  16. Nitrogenated holey two-dimensional structures

    NASA Astrophysics Data System (ADS)

    Mahmood, Javeed; Lee, Eun Kwang; Jung, Minbok; Shin, Dongbin; Jeon, In-Yup; Jung, Sun-Min; Choi, Hyun-Jung; Seo, Jeong-Min; Bae, Seo-Yoon; Sohn, So-Dam; Park, Noejung; Oh, Joon Hak; Shin, Hyung-Joon; Baek, Jong-Beom

    2015-03-01

    Recent graphene research has triggered enormous interest in new two-dimensional ordered crystals constructed by the inclusion of elements other than carbon for bandgap opening. The design of new multifunctional two-dimensional materials with proper bandgap has become an important challenge. Here we report a layered two-dimensional network structure that possesses evenly distributed holes and nitrogen atoms and a C2N stoichiometry in its basal plane. The two-dimensional structure can be efficiently synthesized via a simple wet-chemical reaction and confirmed with various characterization techniques, including scanning tunnelling microscopy. Furthermore, a field-effect transistor device fabricated using the material exhibits an on/off ratio of 107, with calculated and experimental bandgaps of approximately 1.70 and 1.96 eV, respectively. In view of the simplicity of the production method and the advantages of the solution processability, the C2N-h2D crystal has potential for use in practical applications.

  17. Two-Dimensional Turbulence in Magnetized Plasmas

    ERIC Educational Resources Information Center

    Kendl, A.

    2008-01-01

    In an inhomogeneous magnetized plasma the transport of energy and particles perpendicular to the magnetic field is in general mainly caused by quasi two-dimensional turbulent fluid mixing. The physics of turbulence and structure formation is of ubiquitous importance to every magnetically confined laboratory plasma for experimental or industrial…

  18. New two dimensional compounds: beyond graphene

    NASA Astrophysics Data System (ADS)

    Lebegue, Sebastien

    2015-03-01

    In the field of nanosciences, the quest for materials with reduced dimensionality is only at its beginning. While a lot of effort has been put initially on graphene, the focus has been extended in the last past years to functionalized graphene, boron nitride, silicene, and transition metal dichalcogenides in the form of single layers. Although these two-dimensional compounds offer a larger range of properties than graphene, there is a constant need for new materials presenting equivalent or superior performances to the ones already known. Here I will present an approach that we have used to discover potential new two-dimensional materials. This approach corresponds to perform datamining in the Inorganic Crystal Structure Database using simple geometrical criterias, and allowed us to identify nearly 40 new materials that could be exfoliated into two-dimensional sheets. Then, their electronic structure (density of states and bandstructure) was obtained with density functional theory to predict whether the two-dimensional material is metallic or insulating, as well as if it undergoes magnetic ordering at low temperatures. If time allows, I will also present some of our recent results concerning the electronic structure of transition metal dichalcogenides bilayers.

  19. Valley excitons in two-dimensional semiconductors

    DOE PAGESBeta

    Yu, Hongyi; Cui, Xiaodong; Xu, Xiaodong; Yao, Wang

    2014-12-30

    Monolayer group-VIB transition metal dichalcogenides have recently emerged as a new class of semiconductors in the two-dimensional limit. The attractive properties include: the visible range direct band gap ideal for exploring optoelectronic applications; the intriguing physics associated with spin and valley pseudospin of carriers which implies potentials for novel electronics based on these internal degrees of freedom; the exceptionally strong Coulomb interaction due to the two-dimensional geometry and the large effective masses. The physics of excitons, the bound states of electrons and holes, has been one of the most actively studied topics on these two-dimensional semiconductors, where the excitons exhibitmore » remarkably new features due to the strong Coulomb binding, the valley degeneracy of the band edges, and the valley dependent optical selection rules for interband transitions. Here we give a brief overview of the experimental and theoretical findings on excitons in two-dimensional transition metal dichalcogenides, with focus on the novel properties associated with their valley degrees of freedom.« less

  20. Valley excitons in two-dimensional semiconductors

    SciTech Connect

    Yu, Hongyi; Cui, Xiaodong; Xu, Xiaodong; Yao, Wang

    2014-12-30

    Monolayer group-VIB transition metal dichalcogenides have recently emerged as a new class of semiconductors in the two-dimensional limit. The attractive properties include: the visible range direct band gap ideal for exploring optoelectronic applications; the intriguing physics associated with spin and valley pseudospin of carriers which implies potentials for novel electronics based on these internal degrees of freedom; the exceptionally strong Coulomb interaction due to the two-dimensional geometry and the large effective masses. The physics of excitons, the bound states of electrons and holes, has been one of the most actively studied topics on these two-dimensional semiconductors, where the excitons exhibit remarkably new features due to the strong Coulomb binding, the valley degeneracy of the band edges, and the valley dependent optical selection rules for interband transitions. Here we give a brief overview of the experimental and theoretical findings on excitons in two-dimensional transition metal dichalcogenides, with focus on the novel properties associated with their valley degrees of freedom.

  1. Enhanced performance CCD output amplifier

    DOEpatents

    Dunham, Mark E.; Morley, David W.

    1996-01-01

    A low-noise FET amplifier is connected to amplify output charge from a che coupled device (CCD). The FET has its gate connected to the CCD in common source configuration for receiving the output charge signal from the CCD and output an intermediate signal at a drain of the FET. An intermediate amplifier is connected to the drain of the FET for receiving the intermediate signal and outputting a low-noise signal functionally related to the output charge signal from the CCD. The amplifier is preferably connected as a virtual ground to the FET drain. The inherent shunt capacitance of the FET is selected to be at least equal to the sum of the remaining capacitances.

  2. A low-noise 492 GHz SIS waveguide receiver

    NASA Technical Reports Server (NTRS)

    Walker, C. K.; Kooi, J. W.; Chant, M.; Leduc, H. G.; Schaffer, P. L.; Carlstrom, J. E.; Phillips, T. G.

    1992-01-01

    The design and performance are described of an SIS waveguide receiver which provides low noise performance from 375 to 510 GHz. At its design frequency of 492 GHz the receiver has a double-sideband noise temperature of about 172 K. By using embedded magnetic-field concentrators Josephson pair tunneling is effectively suppressed. Techniques for improving receiver performance are discussed.

  3. A low-noise 492 GHz SIS waveguide receiver

    NASA Technical Reports Server (NTRS)

    Walker, C. K.; Kooi, J. W.; Chan, M.; Leduc, Henry G.; Schaffer, P. L.; Carlstrom, J. E.; Phillips, T. G.

    1992-01-01

    We discuss the design and performance of an SIS waveguide receiver which provides low noise performance from 375 to 510 GHz. At its design frequency of 492 GHz, the receiver has a double sideband noise temperature of approx. 172 K. By using embedded magnetic field concentrators, we are able to effectively suppress Josephson pair tunneling. Techniques for improving receiver performance are discussed.

  4. Optical Techniques for Low Noise Microwave Frequency Sources

    NASA Technical Reports Server (NTRS)

    Maleki, Lute

    2005-01-01

    Optical techniques and mathematical models are described for low noise microwave frequency sources. The contents include: 1) Why Optical Techniques; 2) Wavemixing: Advantages and Disadvantages; 3) Wavemixing with Feedback: The OEO; 4) Feedback in both loops: COEO; and 5) State of the Art and Future Prospects.

  5. Radiation Response of Emerging High Gain, Low Noise Detectors

    NASA Technical Reports Server (NTRS)

    Becker, Heidi N.; Farr, William H; Zhu, David Q.

    2007-01-01

    Data illustrating the radiation response of emerging high gain, low noise detectors are presented. Ionizing dose testing of silicon internal discrete avalanche photodiodes, and 51-MeV proton testing of InGaAs/InAlAs avalanche photodiodes operated in Geiger mode are discussed.

  6. Electrometer Amplifier With Overload Protection

    NASA Technical Reports Server (NTRS)

    Woeller, F. H.; Alexander, R.

    1986-01-01

    Circuit features low noise, input offset, and high linearity. Input preamplifier includes input-overload protection and nulling circuit to subtract dc offset from output. Prototype dc amplifier designed for use with ion detector has features desirable in general laboratory and field instrumentation.

  7. A 700mV low power low noise implantable neural recording system design.

    PubMed

    An, Guanglei; Hutchens, Chriswell; Rennaker, Robert L

    2014-01-01

    A low power, low noise implantable neural recording interface for use in a Radio-Frequency Identification (RFID) is presented in this paper. A two stage neural amplifier and 8 bit Pipelined Analog to Digital Converter (ADC) are integrated in this system. The optimized number of amplifier stages demonstrates the minimum power and area consumption; The ADC utilizes a novel offset cancellation technique robust to device leakage to reduce the input offset voltage. The neural amplifier and ADC both utilize 700mV power supply. The midband gain of neural amplifier is 58.4dB with a 3dB bandwidth from 0.71 to 8.26 kHz. Measured input-referred noise and total power consumption are 20.7μVrms and 1.90 respectively. The ADC achieves 8 bit accuracy at 16Ksps with an input voltage of ±400mV. Combined simulation and measurement results demonstrate the neural recording interface's suitability for in situ neutral activity recording. PMID:25571498

  8. Magnetization study of two dimensional helium three

    NASA Astrophysics Data System (ADS)

    Guo, Lei

    This dissertation discusses a magnetization study of a two dimensional Fermi system. Our group developed a SQUID NMR system to study the magnetization of two dimensional 3He on both GTA grafoil and ZYX Graphite substrates. Benefiting from SQUID technology, our NMR experiments were performed at very low applied magnetic field thus avoid the masking of ordering by strong external field. Monolayer 3He films adsorbed on crystalline graphite are considered a nearly ideal example of a two dimensional system of highly correlated fermions. By controlling the 3He areal density, adsorbed films exhibit a wide range of structures with different temperature- dependent magnetic properties and heat capacities. Our recent experiments on two dimensional 3He adsorbed on ZYX graphite focused on the anti-ferromagnetic 4/7 phase and the ferromagnetic incommensurate solid state of a second 3He monolayer. Ferromagnetic order was observed in two dimensional 3He films on both Grafoil and highly oriented ZYX grade exfoliated graphite. The dipolar field plays an important role in magnetic ordering in two dimensional spin systems. The dipole-dipole interaction leads to a frequency shift of the NMR absorption line. The resulting 3He NMR lineshape on Grafoil was a broad peak shifted towards lower frequency with a background from the randomly oriented regions extending to positive frequencies. Compared to Grafoil, ZYX graphite has a much greater structural coherence and is more highly oriented. When studying magnetism of 3He films on ZYX substrate we found that the features we observed in our original Grafoil experiment were much more pronounced on ZYX graphite. In addition, we observed some multi-peak structure on the 3He NMR lineshape, which suggest a series of spin wave resonances. We also studied the magnetic properties of the second layer of 3He films on ZYX substrate at density around 4/7 phase. To eliminate the paramagnetic signal of the first layer solid, we pre-plated a 4He layer on the

  9. Plasmonics with two-dimensional conductors

    PubMed Central

    Yoon, Hosang; Yeung, Kitty Y. M.; Kim, Philip; Ham, Donhee

    2014-01-01

    A wealth of effort in photonics has been dedicated to the study and engineering of surface plasmonic waves in the skin of three-dimensional bulk metals, owing largely to their trait of subwavelength confinement. Plasmonic waves in two-dimensional conductors, such as semiconductor heterojunction and graphene, contrast the surface plasmonic waves on bulk metals, as the former emerge at gigahertz to terahertz and infrared frequencies well below the photonics regime and can exhibit far stronger subwavelength confinement. This review elucidates the machinery behind the unique behaviours of the two-dimensional plasmonic waves and discusses how they can be engineered to create ultra-subwavelength plasmonic circuits and metamaterials for infrared and gigahertz to terahertz integrated electronics. PMID:24567472

  10. Toward two-dimensional search engines

    NASA Astrophysics Data System (ADS)

    Ermann, L.; Chepelianskii, A. D.; Shepelyansky, D. L.

    2012-07-01

    We study the statistical properties of various directed networks using ranking of their nodes based on the dominant vectors of the Google matrix known as PageRank and CheiRank. On average PageRank orders nodes proportionally to a number of ingoing links, while CheiRank orders nodes proportionally to a number of outgoing links. In this way, the ranking of nodes becomes two dimensional which paves the way for the development of two-dimensional search engines of a new type. Statistical properties of information flow on the PageRank-CheiRank plane are analyzed for networks of British, French and Italian universities, Wikipedia, Linux Kernel, gene regulation and other networks. A special emphasis is done for British universities networks using the large database publicly available in the UK. Methods of spam links control are also analyzed.

  11. Two-Dimensional NMR Lineshape Analysis.

    PubMed

    Waudby, Christopher A; Ramos, Andres; Cabrita, Lisa D; Christodoulou, John

    2016-01-01

    NMR titration experiments are a rich source of structural, mechanistic, thermodynamic and kinetic information on biomolecular interactions, which can be extracted through the quantitative analysis of resonance lineshapes. However, applications of such analyses are frequently limited by peak overlap inherent to complex biomolecular systems. Moreover, systematic errors may arise due to the analysis of two-dimensional data using theoretical frameworks developed for one-dimensional experiments. Here we introduce a more accurate and convenient method for the analysis of such data, based on the direct quantum mechanical simulation and fitting of entire two-dimensional experiments, which we implement in a new software tool, TITAN (TITration ANalysis). We expect the approach, which we demonstrate for a variety of protein-protein and protein-ligand interactions, to be particularly useful in providing information on multi-step or multi-component interactions. PMID:27109776

  12. Two-dimensional ranking of Wikipedia articles

    NASA Astrophysics Data System (ADS)

    Zhirov, A. O.; Zhirov, O. V.; Shepelyansky, D. L.

    2010-10-01

    The Library of Babel, described by Jorge Luis Borges, stores an enormous amount of information. The Library exists ab aeterno. Wikipedia, a free online encyclopaedia, becomes a modern analogue of such a Library. Information retrieval and ranking of Wikipedia articles become the challenge of modern society. While PageRank highlights very well known nodes with many ingoing links, CheiRank highlights very communicative nodes with many outgoing links. In this way the ranking becomes two-dimensional. Using CheiRank and PageRank we analyze the properties of two-dimensional ranking of all Wikipedia English articles and show that it gives their reliable classification with rich and nontrivial features. Detailed studies are done for countries, universities, personalities, physicists, chess players, Dow-Jones companies and other categories.

  13. Kirigami for Two-Dimensional Electronic Membranes

    NASA Astrophysics Data System (ADS)

    Qi, Zenan; Bahamon, Dario; Campbell, David; Park, Harold

    2015-03-01

    Two-dimensional materials have recently drawn tremendous attention because of their unique properties. In this work, we introduce the notion of two-dimensional kirigami, where concepts that have been used almost exclusively for macroscale structures are applied to dramatically enhance their stretchability. Specifically, we show using classical molecular dynamics simulations that the yield and fracture strains of graphene and MoS2 can be enhanced by about a factor of three using kirigami as compared to standard monolayers. Finally, using graphene as an example, we demonstrate that the kirigami structure may open up interesting opportunities in coupling to the electronic behavior of 2D materials. Authors acknowledge Mechanical Engineering and Physics departments at Boston University, and Mackgrafe at Mackenzie Presbyterian University.

  14. Two-Dimensional NMR Lineshape Analysis

    PubMed Central

    Waudby, Christopher A.; Ramos, Andres; Cabrita, Lisa D.; Christodoulou, John

    2016-01-01

    NMR titration experiments are a rich source of structural, mechanistic, thermodynamic and kinetic information on biomolecular interactions, which can be extracted through the quantitative analysis of resonance lineshapes. However, applications of such analyses are frequently limited by peak overlap inherent to complex biomolecular systems. Moreover, systematic errors may arise due to the analysis of two-dimensional data using theoretical frameworks developed for one-dimensional experiments. Here we introduce a more accurate and convenient method for the analysis of such data, based on the direct quantum mechanical simulation and fitting of entire two-dimensional experiments, which we implement in a new software tool, TITAN (TITration ANalysis). We expect the approach, which we demonstrate for a variety of protein-protein and protein-ligand interactions, to be particularly useful in providing information on multi-step or multi-component interactions. PMID:27109776

  15. Deeply subrecoil two-dimensional Raman cooling

    SciTech Connect

    Boyer, V.; Phillips, W.D.; Lising, L.J.; Rolston, S.L.

    2004-10-01

    We report the implementation of a two-dimensional Raman cooling scheme using sequential excitations along the orthogonal axes. Using square pulses, we have cooled a cloud of ultracold cesium atoms down to an rms velocity spread of 0.39(5) recoil velocities, corresponding to an effective transverse temperature of 30 nK (0.15T{sub rec}). This technique can be useful to improve cold-atom atomic clocks and is particularly relevant for clocks in microgravity.

  16. Two-dimensional tungsten oxide nanowire networks

    NASA Astrophysics Data System (ADS)

    Zhao, Y. M.; Li, Y. H.; Ahmad, I.; McCartney, D. G.; Zhu, Y. Q.; Hu, W. B.

    2006-09-01

    The authors report the synthesis and characterization of two-dimensional (2D) single crystalline nanonetworks consisting of tungsten oxide nanowires with diameters of ca. 20nm. The 2D networks are believed to result from the nanowire growth along the four crystallographic equivalent directions of ⟨110⟩ in the tetragonal WO2.9 structure. These 2D tungsten oxide networks may be potential precursors for creating 2D networks comprising WS2 nanotubes.

  17. Fully localized two-dimensional embedded solitons

    SciTech Connect

    Yang Jianke

    2010-11-15

    We report the prediction of fully localized two-dimensional embedded solitons. These solitons are obtained in a quasi-one-dimensional waveguide array which is periodic along one spatial direction and localized along the orthogonal direction. Under appropriate nonlinearity, these solitons are found to exist inside the Bloch bands (continuous spectrum) of the waveguide and thus are embedded solitons. These embedded solitons are fully localized along both spatial directions. In addition, they are fully stable under perturbations.

  18. Two-dimensional structured illumination microscopy.

    PubMed

    Schropp, M; Uhl, R

    2014-10-01

    In widefield fluorescence microscopy, images from all but very flat samples suffer from fluorescence emission from layers above or below the focal plane of the objective lens. Structured illumination microscopy provides an elegant approach to eliminate this unwanted image contribution. To this end a line grid is projected onto the sample and phase images are taken at different positions of the line grid. Using suitable algorithms 'quasi-confocal images' can be derived from a given number of such phase-images. Here, we present an alternative structured illumination microscopy approach, which employs two-dimensional patterns instead of a one-dimensional one. While in one-dimensional structured illumination microscopy the patterns are shifted orthogonally to the pattern orientation, in our two-dimensional approach it is shifted at a single, pattern-dependent angle, yet it already achieves an isotropic power spectral density with this unidirectional shift, which otherwise would require a combination of pattern-shift and -rotation. Moreover, our two-dimensional approach also yields a better signal-to-noise ratio in the evaluated image. PMID:25113075

  19. Low Noise Performance Perspectives Of Wideband Aperture Phased Arrays

    NASA Astrophysics Data System (ADS)

    Woestenburg, E. E. M.; Kuenen, J. C.

    2004-06-01

    A general analysis of phased array noise properties and measurements, applied to one square meter tiles of the Thousand Element Array (THEA), has resulted in a procedure to define the noise budget for a THEA-tile (Woestenburg and Dijkstra, 2003). The THEA system temperature includes LNA and receiver noise, antenna connecting loss, noise coupling between antenna elements and other possible contributions. This paper discusses the various noise contributions to the THEA system temperature and identifies the areas where improvement can be realized. We will present better understanding of the individual noise contributions using measurements and analysis of single antenna/receiver elements. An improved design for a 1-m2 Low Noise Tile (LNT) will be discussed and optimized low noise performance for the LNT is presented. We will also give future perspectives of the noise performance for such tiles, in relation to the requirements for SKA in the 1 GHz frequency range.

  20. 52 W kHz-linewidth low-noise linearly-polarized all-fiber single-frequency MOPA laser

    NASA Astrophysics Data System (ADS)

    Yang, Changsheng; Xu, Shanhui; Chen, Dan; Zhang, Yuanfei; Zhao, Qilai; Li, Can; Zhou, Kaijun; Feng, Zhouming; Gan, Jiulin; Yang, Zhongmin

    2016-05-01

    An all-fiber Yb-doped kHz-linewidth low-noise linearly polarized single-frequency master-oscillator power-amplifier (MOPA) laser with a stable CW output power of >52 W is demonstrated. By suppressing the intensity noise of the DBR phosphate fiber oscillator, the linewidth of MOPA laser is not noticeably broadened, and an ultra-narrow linewidth of <3 kHz is obtained. Furthermore, the low-noise behavior of MOPA lasers is investigated. A measured relative intensity noise of < -130 dB Hz-1 at frequencies of over 2 MHz, a phase noise above 1 kHz of <5 μrad/Hz1/2, and a signal-to-noise ratio of >63 dB are achieved.

  1. Design and Testing of a Low Noise Flight Guidance Concept

    NASA Technical Reports Server (NTRS)

    Williams, David H.; Oseguera-Lohr, Rosa M.; Lewis, Elliot T.

    2004-01-01

    A flight guidance concept was developed to assist in flying continuous descent approach (CDA) procedures designed to lower the noise under the flight path of jet transport aircraft during arrival operations at an airport. The guidance consists of a trajectory prediction algorithm that was tuned to produce a high-efficiency, low noise flight profile with accompanying autopilot and flight display elements needed by the flight control system and pilot to fly the approach. A key component of the flight guidance was a real-time display of energy error relative to the predicted flight path. The guidance was integrated with the conventional Flight Management System (FMS) guidance of a modern jet transport airplane and tested in a high fidelity flight simulation. A charted arrival procedure, which allowed flying conventional arrivals, CDA arrivals with standard guidance, and CDA arrivals with the new low noise guidance, was developed to assist in the testing and evaluation of the low noise guidance concept. Results of the simulation testing showed the low noise guidance was easy to use by airline pilot test subjects and effective in achieving the desired noise reduction. Noise under the flight path was reduced by at least 2 decibels in Sound Exposure Level (SEL) at distances from about 3 nautical miles out to about 17.5 nautical miles from the runway, with a peak reduction of 8.5 decibels at about 10.5 nautical miles. Fuel consumption was also reduced by about 17% for the LNG conditions compared to baseline runs for the same flight distance. Pilot acceptance and understanding of the guidance was quite high with favorable comments and ratings received from all test subjects.

  2. Low noise, 0.4-3 GHz cryogenic receiver for radio astronomy.

    PubMed

    Gawande, R; Bradley, R; Langston, G

    2014-10-01

    We present the design and measurement of a radio telescope receiver front end cooled to 100 K physical temperature, and working over 400 MHz to 3 GHz frequency band. The system uses a frequency independent feed developed for operation as a feed for parabola using sinuous elements and integrated with an ultra-wideband low noise amplifier. The ambient temperature system is tested on the 43 m radio telescope in Green Bank, WV and the system verification results on the sky are presented. The cryogenic receiver is developed using a Stirling cycle, one stage cryocooler. The measured far field patterns and the system noise less than 80 K over a 5:1 bandwidth are presented. PMID:25362437

  3. Low-noise CMOS preamplifier operating at 4.2 K

    NASA Astrophysics Data System (ADS)

    Kleine, U.; Bieger, J.; Seifert, H.

    1994-08-01

    A low-noise CMOS readout preamplifier operating at liquid helium temperatures is described. In conjunction with magnetic field sensors applying SQUIDS (Superconducting QUantum Interference Device) the preamplifier can be used to measure biomagnetic fields of human brain and heart noninvasively. The input of the folded cascode amplifier can be attached directly to a low impedance SQUID output. This way the commonly used discrete LC tank resonator circuit for impedance matching can be omitted. An equivalent noise voltage density of 0.3 nV/square root of Hz at 500 kHz has been measured. Despite the occurrence of the kink effect and other abnormalities in MOS transistor characteristics at 4.2 K, during the tests no abnormal operation has been observed. Such a preamplifier circuit is essential in simplifying the expensive shielding currently used in biomagnetic diagnosis systems.

  4. On-wafer, cryogenic characterization of ultra-low noise HEMT devices

    NASA Technical Reports Server (NTRS)

    Bautista, J. J.; Laskar, J.; Szydlik, P.

    1995-01-01

    Significant advances in the development of high electron-mobility field-effect transistors (HEMT's) have resulted in cryogenic, low-noise amplifiers (LNA's) whose noise temperatures are within an order of magnitude of the quantum noise limit (hf/k). Further advances in HEMT technology at cryogenic temperatures may eventually lead to the replacement of maser and superconducting insulator superconducting front ends in the 1- to 100-GHz frequency band. Key to identification of the best HEMT's and optimization of cryogenic LNA's are accurate and repeatable device measurements at cryogenic temperatures. This article describes the design and operation of a cryogenic coplanar waveguide probe system for the characterization and modeling of advanced semiconductor transistors at cryogenic temperatures. Results on advanced HEMT devices are presented to illustrate the utility of the measurement system.

  5. A low noise CMOS RF front-end for UWB 6-9 GHz applications

    NASA Astrophysics Data System (ADS)

    Feng, Zhou; Ting, Gao; Fei, Lan; Wei, Li; Ning, Li; Junyan, Ren

    2010-11-01

    An integrated fully differential ultra-wideband CMOS RF front-end for 6-9 GHz is presented. A resistive feedback low noise amplifier and a gain controllable IQ merged folded quadrature mixer are integrated as the RF front-end. The ESD protected chip is fabricated in a TSMC 0.13 μm RF CMOS process and achieves a maximum voltage gain of 23-26 dB and a minimum voltage gain of 16-19 dB, an averaged total noise figure of 3.3-4.6 dB while operating in the high gain mode and an in-band IIP3 of -12.6 dBm while in the low gain mode. This RF front-end consumes 17 mA from a 1.2 V supply voltage.

  6. Low-noise analog readout channel for SDD in X-ray spectrometry

    NASA Astrophysics Data System (ADS)

    Atkin, E.; Gusev, A.; Krivchenko, A.; Levin, V.; Malankin, E.; Normanov, D.; Rotin, A.; Sagdiev, I.; Samsonov, V.

    2016-01-01

    A low-noise analog readout channel optimized for operation with the Silicon Drift Detectors (SDDs) with built-in JFET is presented. The Charge Sensitive Amplifier (CSA) operates in a pulse reset mode using the reset diode built-in the SDD detector. The shaper is a 6th order semi-Gaussian filter with switchable discrete shaping times. The readout channel provides the Equivalent Noise Charge (ENC) of 12e- (simulation) and input dynamic range of 30 keV . The measured energy resolution at the 5,89 keV line of a 55Fe X-ray source is 336 eV (FWHM). The channel was prototyped via Europractice in the AMS 350 nm process as miniASIC. The simulation and first measurement results are presented in the paper.

  7. SCAPS, a two-dimensional ion detector for mass spectrometer

    NASA Astrophysics Data System (ADS)

    Yurimoto, Hisayoshi

    2014-05-01

    Faraday Cup (FC) and electron multiplier (EM) are of the most popular ion detector for mass spectrometer. FC is used for high-count-rate ion measurements and EM can detect from single ion. However, FC is difficult to detect lower intensities less than kilo-cps, and EM loses ion counts higher than Mega-cps. Thus, FC and EM are used complementary each other, but they both belong to zero-dimensional detector. On the other hand, micro channel plate (MCP) is a popular ion signal amplifier with two-dimensional capability, but additional detection system must be attached to detect the amplified signals. Two-dimensional readout for the MCP signals, however, have not achieve the level of FC and EM systems. A stacked CMOS active pixel sensor (SCAPS) has been developed to detect two-dimensional ion variations for a spatial area using semiconductor technology [1-8]. The SCAPS is an integrated type multi-detector, which is different from EM and FC, and is composed of more than 500×500 pixels (micro-detectors) for imaging of cm-area with a pixel of less than 20 µm in square. The SCAPS can be detected from single ion to 100 kilo-count ions per one pixel. Thus, SCAPS can be accumulated up to several giga-count ions for total pixels, i.e. for total imaging area. The SCAPS has been applied to stigmatic ion optics of secondary ion mass spectrometer, as a detector of isotope microscope [9]. The isotope microscope has capabilities of quantitative isotope images of hundred-micrometer area on a sample with sub-micrometer resolution and permil precision, and of two-dimensional mass spectrum on cm-scale of mass dispersion plane of a sector magnet with ten-micrometer resolution. The performance has been applied to two-dimensional isotope spatial distribution for mainly hydrogen, carbon, nitrogen and oxygen of natural (extra-terrestrial and terrestrial) samples and samples simulated natural processes [e.g. 10-17]. References: [1] Matsumoto, K., et al. (1993) IEEE Trans. Electron Dev. 40

  8. Two-Dimensional Synthetic-Aperture Radiometer

    NASA Technical Reports Server (NTRS)

    LeVine, David M.

    2010-01-01

    A two-dimensional synthetic-aperture radiometer, now undergoing development, serves as a test bed for demonstrating the potential of aperture synthesis for remote sensing of the Earth, particularly for measuring spatial distributions of soil moisture and ocean-surface salinity. The goal is to use the technology for remote sensing aboard a spacecraft in orbit, but the basic principles of design and operation are applicable to remote sensing from aboard an aircraft, and the prototype of the system under development is designed for operation aboard an aircraft. In aperture synthesis, one utilizes several small antennas in combination with a signal processing in order to obtain resolution that otherwise would require the use of an antenna with a larger aperture (and, hence, potentially more difficult to deploy in space). The principle upon which this system is based is similar to that of Earth-rotation aperture synthesis employed in radio astronomy. In this technology the coherent products (correlations) of signals from pairs of antennas are obtained at different antenna-pair spacings (baselines). The correlation for each baseline yields a sample point in a Fourier transform of the brightness-temperature map of the scene. An image of the scene itself is then reconstructed by inverting the sampled transform. The predecessor of the present two-dimensional synthetic-aperture radiometer is a one-dimensional one, named the Electrically Scanned Thinned Array Radiometer (ESTAR). Operating in the L band, the ESTAR employs aperture synthesis in the cross-track dimension only, while using a conventional antenna for resolution in the along-track dimension. The two-dimensional instrument also operates in the L band to be precise, at a frequency of 1.413 GHz in the frequency band restricted for passive use (no transmission) only. The L band was chosen because (1) the L band represents the long-wavelength end of the remote- sensing spectrum, where the problem of achieving adequate

  9. Transport in two-dimensional paper networks

    PubMed Central

    Fu, Elain; Ramsey, Stephen A.; Kauffman, Peter; Lutz, Barry; Yager, Paul

    2011-01-01

    Two-dimensional paper networks (2DPNs) hold great potential for transcending the capabilities and performance of today's paper-based analytical devices. Specifically, 2DPNs enable sophisticated multi-step chemical processing sequences for sample pretreatment and analysis at a cost and ease-of-use that make them appropriate for use in settings with low resources. A quantitative understanding of flow in paper networks is essential to realizing the potential of these networks. In this report, we provide a framework for understanding flow in simple 2DPNs using experiments, analytical expressions, and computational simulations. PMID:22140373

  10. Couette flow of two-dimensional foams

    NASA Astrophysics Data System (ADS)

    Katgert, G.; Tighe, B. P.; Möbius, M. E.; van Hecke, M.

    2010-06-01

    We experimentally investigate flow of quasi-two-dimensional disordered foams in Couette geometries, both for foams squeezed below a top plate and for freely floating foams (bubble rafts). With the top plate, the flows are strongly localized and rate dependent. For the bubble rafts the flow profiles become essentially rate independent, the local and global rheology do not match, and in particular the foam flows in regions where the stress is below the global yield stress. We attribute this to nonlocal effects and show that the "fluidity" model recently introduced by Goyon et al. (Nature, 454 (2008) 84) captures the essential features of flow both with and without a top plate.

  11. Program For Two-Dimensional Thermoplastic Deformation

    NASA Technical Reports Server (NTRS)

    Orient, George E.

    1993-01-01

    SOLAS contains number of utility programs for use with finite-element simulations. Designed to handle two-dimensional problems of quasi-static thermoplastic deformation. Includes optional postprocessing software, independent of solution codes, generating unified element-by-element list of quantitative results of computation, plus file containing signed equivalent stresses, equivalent strains, and multiaxiality factor parameter. Signs of equivalent quantities expressed either with respect to maximum principal quantities or with respect to directions defined by user. Written in UNIX shell script and FORTRAN 77.

  12. Can Two-Dimensional Boron Superconduct?

    PubMed

    Penev, Evgeni S; Kutana, Alex; Yakobson, Boris I

    2016-04-13

    Two-dimensional boron is expected to exhibit various structural polymorphs, all being metallic. Additionally, its small atomic mass suggests strong electron-phonon coupling, which in turn can enable superconducting behavior. Here we perform first-principles analysis of electronic structure, phonon spectra, and electron-phonon coupling of selected 2D boron polymorphs and show that the most stable structures predicted to feasibly form on a metal substrate should also exhibit intrinsic phonon-mediated superconductivity, with estimated critical temperature in the range of Tc ≈ 10-20 K. PMID:27003635

  13. Two-dimensional meniscus in a wedge

    SciTech Connect

    Kagan, M.; Pinczewski, W.V.; Oren, P.E.

    1995-03-15

    This paper presents a closed-form analytical solution of the augmented Young-Laplace equation for the meniscus profile in a two-dimensional wedge-shaped capillary. The solution is valid for monotonic forms of disjoining pressure which are repulsive in nature. In the limit of negligible disjoining pressure, it is shown to reduce to the classical solution of constant curvature. The character of the solution is examined and examples of practical interest which demonstrate the application of the solution to the computation of the meniscus profile in a wedge-shaped capillary are discussed.

  14. Pressure of two-dimensional Yukawa liquids

    NASA Astrophysics Data System (ADS)

    Feng, Yan; Goree, J.; Liu, Bin; Wang, Lei; Tian, Wen-de

    2016-06-01

    A simple analytic expression for the pressure of a two-dimensional Yukawa liquid is found by fitting results from a molecular dynamics simulation. The results verify that the pressure can be written as the sum of a potential term which is a simple multiple of the Coulomb potential energy at a distance of the Wigner–Seitz radius, and a kinetic term which is a multiple of the one for an ideal gas. Dimensionless coefficients for each of these terms are found empirically, by fitting. The resulting analytic expression, with its empirically determined coefficients, is plotted as isochores, or curves of constant area. These results should be applicable to monolayer dusty plasmas.

  15. Two dimensional thick center vortex model

    NASA Astrophysics Data System (ADS)

    Rafibakhsh, Shahnoosh; Ahmadi, Alireza

    2016-01-01

    The potential between static color source is calculated in the SU (3) gauge group by introducing a two dimensional vortex flux. To generalize the model, the length of the Wilson loop is equal to R oriented along the x axis, and the vortex flux is considered as a function of x and y. The comparison between the generalized model and the original one shows that the intermediate linear regime is increased significantly and better agreement with Casimir scaling is achieved. Furthermore, the model is applied to calculate the potential between baryons.

  16. Superconductivity in two-dimensional boron allotropes

    NASA Astrophysics Data System (ADS)

    Zhao, Yinchang; Zeng, Shuming; Ni, Jun

    2016-01-01

    We use ab initio evolutionary algorithm and first-principles calculations to investigate structural, electronic, vibrational, and superconducting properties of two-dimensional (2 D ) boron allotropes. Remarkably, we show that conventional BCS superconductivity in the stable 2 D boron structures is ubiquitous with the critical temperature Tc above the liquid hydrogen temperature for certain configurations. Due to the electronic states of the Fermi surface originating from both σ and π electrons, the superconductivity of the 2 D structures arises from multiple phonon modes. Our results support that 2 D boron structure may be a pure single-element material with the highest Tc on conditions without high pressure and external strain.

  17. Quasicondensation in Two-Dimensional Fermi Gases.

    PubMed

    Wu, Chien-Te; Anderson, Brandon M; Boyack, Rufus; Levin, K

    2015-12-11

    In this paper we follow the analysis and protocols of recent experiments, combined with simple theory, to arrive at a physical understanding of quasi-condensation in two dimensional Fermi gases. A key signature of quasi-condensation, which contains aspects of Berezinskiĭ-Kosterlitz-Thouless behavior, is a strong zero momentum peak in the pair momentum distribution. Importantly, this peak emerges at a reasonably well defined onset temperature. The resulting phase diagram, pair momentum distribution, and algebraic power law decay are compatible with recent experiments throughout the continuum from BEC to BCS. PMID:26705613

  18. Fractures in heterogeneous two-dimensional systems

    NASA Astrophysics Data System (ADS)

    Politi, Antonio; Zei, Maria

    2001-05-01

    A two-dimensional triangular lattice with bond disorder is used as a testing ground for fracture behavior in heterogeneous materials in strain-controlled conditions. Simulations are performed with two interaction potentials (harmonic and Lennard-Jones types) and different breaking thresholds. We study the strain range where the fracture progressively develops from the first to the last breakdown. Scaling properties with the lattice size are investigated: no qualitative difference is found between the two interaction potentials. Clustering properties of the broken bonds are also studied by grouping them into disjoint sets of connected bonds. Finally, the role of kinetic energy is analyzed by comparing overdamped with dissipationless dynamics.

  19. Numerical simulations of two-dimensional QED

    SciTech Connect

    Carson, S.R.; Kenway, R.D.

    1986-02-01

    We describe the computer simulation of two-dimensional QED on a 64 x 64 Euclidean space-time lattice using the Susskind lattice fermion action. Theorder parameter for chiral symmetry breaking and the low-lying meson masses are calculated for both the model with two continuum flavours, which arises naturally in this formulation, and the model with one continuum falvour obtained by including a nonsymmetric mass term and setting one fermion mass equal to the cut-off. Results are compared with those obtined using the quenched approximation, and with analytic predictions.

  20. Two-dimensional shape memory graphene oxide.

    PubMed

    Chang, Zhenyue; Deng, Junkai; Chandrakumara, Ganaka G; Yan, Wenyi; Liu, Jefferson Zhe

    2016-01-01

    Driven by the increasing demand for micro-/nano-technologies, stimuli-responsive shape memory materials at nanoscale have recently attracted great research interests. However, by reducing the size of conventional shape memory materials down to approximately nanometre range, the shape memory effect diminishes. Here, using density functional theory calculations, we report the discovery of a shape memory effect in a two-dimensional atomically thin graphene oxide crystal with ordered epoxy groups, namely C8O. A maximum recoverable strain of 14.5% is achieved as a result of reversible phase transition between two intrinsically stable phases. Our calculations conclude co-existence of the two stable phases in a coherent crystal lattice, giving rise to the possibility of constructing multiple temporary shapes in a single material, thus, enabling highly desirable programmability. With an atomic thickness, excellent shape memory mechanical properties and electric field stimulus, the discovery of a two-dimensional shape memory graphene oxide opens a path for the development of exceptional micro-/nano-electromechanical devices. PMID:27325441

  1. Two-dimensional shape memory graphene oxide

    PubMed Central

    Chang, Zhenyue; Deng, Junkai; Chandrakumara, Ganaka G.; Yan, Wenyi; Liu, Jefferson Zhe

    2016-01-01

    Driven by the increasing demand for micro-/nano-technologies, stimuli-responsive shape memory materials at nanoscale have recently attracted great research interests. However, by reducing the size of conventional shape memory materials down to approximately nanometre range, the shape memory effect diminishes. Here, using density functional theory calculations, we report the discovery of a shape memory effect in a two-dimensional atomically thin graphene oxide crystal with ordered epoxy groups, namely C8O. A maximum recoverable strain of 14.5% is achieved as a result of reversible phase transition between two intrinsically stable phases. Our calculations conclude co-existence of the two stable phases in a coherent crystal lattice, giving rise to the possibility of constructing multiple temporary shapes in a single material, thus, enabling highly desirable programmability. With an atomic thickness, excellent shape memory mechanical properties and electric field stimulus, the discovery of a two-dimensional shape memory graphene oxide opens a path for the development of exceptional micro-/nano-electromechanical devices. PMID:27325441

  2. Two-dimensional shape memory graphene oxide

    NASA Astrophysics Data System (ADS)

    Chang, Zhenyue; Deng, Junkai; Chandrakumara, Ganaka G.; Yan, Wenyi; Liu, Jefferson Zhe

    2016-06-01

    Driven by the increasing demand for micro-/nano-technologies, stimuli-responsive shape memory materials at nanoscale have recently attracted great research interests. However, by reducing the size of conventional shape memory materials down to approximately nanometre range, the shape memory effect diminishes. Here, using density functional theory calculations, we report the discovery of a shape memory effect in a two-dimensional atomically thin graphene oxide crystal with ordered epoxy groups, namely C8O. A maximum recoverable strain of 14.5% is achieved as a result of reversible phase transition between two intrinsically stable phases. Our calculations conclude co-existence of the two stable phases in a coherent crystal lattice, giving rise to the possibility of constructing multiple temporary shapes in a single material, thus, enabling highly desirable programmability. With an atomic thickness, excellent shape memory mechanical properties and electric field stimulus, the discovery of a two-dimensional shape memory graphene oxide opens a path for the development of exceptional micro-/nano-electromechanical devices.

  3. Two-Dimensional Low-Turbulence Tunnel

    NASA Technical Reports Server (NTRS)

    1938-01-01

    Construction of the wood frame for the Two-Dimensional Low-Turbulence Tunnel. The Two-Dimensional Low-Turbulence Tunnel was originally called the Refrigeration or 'Ice' tunnel because it was intended to support research on aircraft icing. The tunnel was built of wood, lined with sheet steel, and heavily insulated on the outside. Refrigeration equipment was installed to generate icing conditions inside the test section. The NACA sent out a questionnaire to airline operators, asking them to detail the specific kinds of icing problems they encountered in flight. The replies became the basis for a comprehensive research program begun in 1938 when the tunnel commenced operation. Research quickly focused on the concept of using exhaust heat to prevent ice from forming on the wing's leading edge. This project was led by Lewis Rodert, who later would win the Collier Trophy for his work on deicing. By 1940, aircraft icing research had shifted to the new Ames Research Laboratory, and the Ice tunnel was refitted with screens and honeycomb. Researchers were trying to eliminate all turbulence in the test section. From TN 1283: 'The Langley two-dimensional low-turbulence pressure tunnel is a single-return closed-throat tunnel.... The tunnel is constructed of heavy steel plate so that the pressure of the air may be varied from approximately full vacuum to 10 atmospheres absolute, thereby giving a wide range of air densities. Reciprocating compressors with a capacity of 1200 cubic feet of free air per minute provide compressed air. Since the tunnel shell has a volume of about 83,000 cubic feet, a compression rate of approximately one atmosphere per hour is obtained. ... The test section is rectangular in shape, 3 feet wide, 7 1/2 feet high, and 7 1/2 feet long. ... The over-all size of the wind-tunnel shell is about 146 feet long and 58 feet wide with a maximum diameter of 26 feet. The test section and entrance and exit cones are surrounded by a 22-foot diameter section of the

  4. Two-Dimensional Low-Turbulence Tunnel

    NASA Technical Reports Server (NTRS)

    1937-01-01

    Construction of the Two-Dimensional Low-Turbulence Tunnel. The Two-Dimensional Low-Turbulence Tunnel was originally called the Refrigeration or 'Ice' tunnel because it was intended to support research on aircraft icing. The tunnel was built of wood, lined with sheet steel, and heavily insulated on the outside. Refrigeration equipment was installed to generate icing conditions inside the test section. The NACA sent out a questionnaire to airline operators, asking them to detail the specific kinds of icing problems they encountered in flight. The replies became the basis for a comprehensive research program begun in 1938 when the tunnel commenced operation. Research quickly focused on the concept of using exhaust heat to prevent ice from forming on the wing's leading edge. This project was led by Lewis Rodert, who later would win the Collier Trophy for his work on deicing. By 1940, aircraft icing research had shifted to the new Ames Research Laboratory, and the Ice tunnel was refitted with screens and honeycomb. Researchers were trying to eliminate all turbulence in the test section. From TN 1283: 'The Langley two-dimensional low-turbulence pressure tunnel is a single-return closed-throat tunnel.... The tunnel is constructed of heavy steel plate so that the pressure of the air may be varied from approximately full vacuum to 10 atmospheres absolute, thereby giving a wide range of air densities. Reciprocating compressors with a capacity of 1200 cubic feet of free air per minute provide compressed air. Since the tunnel shell has a volume of about 83,000 cubic feet, a compression rate of approximately one atmosphere per hour is obtained. ... The test section is rectangular in shape, 3 feet wide, 7 1/2 feet high, and 7 1/2 feet long. ... The over-all size of the wind-tunnel shell is about 146 feet long and 58 feet wide with a maximum diameter of 26 feet. The test section and entrance and exit cones are surrounded by a 22-foot diameter section of the shell to provide a

  5. Two-Dimensional Low-Turbulence Tunnel

    NASA Technical Reports Server (NTRS)

    1938-01-01

    Manometer for the Two-Dimensional Low-Turbulence Tunnel. The Two-Dimensional Low-Turbulence Tunnel was originally called the Refrigeration or 'Ice' tunnel because it was intended to support research on aircraft icing. The tunnel was built of wood, lined with sheet steel, and heavily insulated on the outside. Refrigeration equipment was installed to generate icing conditions inside the test section. The NACA sent out a questionnaire to airline operators, asking them to detail the specific kinds of icing problems they encountered in flight. The replies became the basis for a comprehensive research program begun in 1938 when the tunnel commenced operation. Research quickly focused on the concept of using exhaust heat to prevent ice from forming on the wing's leading edge. This project was led by Lewis Rodert, who later would win the Collier Trophy for his work on deicing. By 1940, aircraft icing research had shifted to the new Ames Research Laboratory, and the Ice tunnel was refitted with screens and honeycomb. Researchers were trying to eliminate all turbulence in the test section. From TN 1283: 'The Langley two-dimensional low-turbulence pressure tunnel is a single-return closed-throat tunnel.... The tunnel is constructed of heavy steel plate so that the pressure of the air may be varied from approximately full vacuum to 10 atmospheres absolute, thereby giving a wide range of air densities. Reciprocating compressors with a capacity of 1200 cubic feet of free air per minute provide compressed air. Since the tunnel shell has a volume of about 83,000 cubic feet, a compression rate of approximately one atmosphere per hour is obtained. ... The test section is rectangular in shape, 3 feet wide, 7 1/2 feet high, and 7 1/2 feet long. ... The over-all size of the wind-tunnel shell is about 146 feet long and 58 feet wide with a maximum diameter of 26 feet. The test section and entrance and exit cones are surrounded by a 22-foot diameter section of the shell to provide a space

  6. A 0.5-V multi-channel low-noise readout front-end for portable EEG acquisition.

    PubMed

    Wen-Yen Huang; Yu-Wei Cheng; Kea-Tiong Tang

    2015-08-01

    This article presents a low-noise readout front-end suitable for Electroencephalogram (EEG) acquisition. The chip includes 8-channel fully-differential instrumentation amplifiers, utilizing chopper stabilization technique for reducing the flicker noise, each amplifier with a small Gm-C low-pass filter, a programmable gain amplifier, and a 10-bit successive approximation register (SAR) ADC with a detect logic for DAC switching. The chip is fabricated with the TSMC 90nm CMOS process. The low-noise readout front-end has simulated frequency response from 0.57 Hz to 213 Hz, programmable gain from 54.4 dB to 87.6 dB, integrated input-referred noise of 0.358 μVrms within EEG bandwidth, a noise efficiency factor (NEF) of 2.43, and a power efficiency factor (PEF) of 2.95. The overall system consumes 32.08 μW under 0.5-V supply. PMID:26736392

  7. Two-dimensional fourier transform spectrometer

    DOEpatents

    DeFlores, Lauren; Tokmakoff, Andrei

    2013-09-03

    The present invention relates to a system and methods for acquiring two-dimensional Fourier transform (2D FT) spectra. Overlap of a collinear pulse pair and probe induce a molecular response which is collected by spectral dispersion of the signal modulated probe beam. Simultaneous collection of the molecular response, pulse timing and characteristics permit real time phasing and rapid acquisition of spectra. Full spectra are acquired as a function of pulse pair timings and numerically transformed to achieve the full frequency-frequency spectrum. This method demonstrates the ability to acquire information on molecular dynamics, couplings and structure in a simple apparatus. Multi-dimensional methods can be used for diagnostic and analytical measurements in the biological, biomedical, and chemical fields.

  8. Epitaxial growth of two-dimensional stanene

    NASA Astrophysics Data System (ADS)

    Zhu, Feng-Feng; Chen, Wei-Jiong; Xu, Yong; Gao, Chun-Lei; Guan, Dan-Dan; Liu, Can-Hua; Qian, Dong; Zhang, Shou-Cheng; Jia, Jin-Feng

    2015-10-01

    Following the first experimental realization of graphene, other ultrathin materials with unprecedented electronic properties have been explored, with particular attention given to the heavy group-IV elements Si, Ge and Sn. Two-dimensional buckled Si-based silicene has been recently realized by molecular beam epitaxy growth, whereas Ge-based germanene was obtained by molecular beam epitaxy and mechanical exfoliation. However, the synthesis of Sn-based stanene has proved challenging so far. Here, we report the successful fabrication of 2D stanene by molecular beam epitaxy, confirmed by atomic and electronic characterization using scanning tunnelling microscopy and angle-resolved photoemission spectroscopy, in combination with first-principles calculations. The synthesis of stanene and its derivatives will stimulate further experimental investigation of their theoretically predicted properties, such as a 2D topological insulating behaviour with a very large bandgap, and the capability to support enhanced thermoelectric performance, topological superconductivity and the near-room-temperature quantum anomalous Hall effect.

  9. Two-dimensional nuclear magnetic resonance petrophysics.

    PubMed

    Sun, Boqin; Dunn, Keh-Jim

    2005-02-01

    Two-dimensional nuclear magnetic resonance (2D NMR) opens a wide area for exploration in petrophysics and has significant impact to petroleum logging technology. When there are multiple fluids with different diffusion coefficients saturated in a porous medium, this information can be extracted and clearly delineated from CPMG measurements of such a system either using regular pulsing sequences or modified two window sequences. The 2D NMR plot with independent variables of T2 relaxation time and diffusion coefficient allows clear separation of oil and water signals in the rocks. This 2D concept can be extended to general studies of fluid-saturated porous media involving other combinations of two or more independent variables, such as chemical shift and T1/T2 relaxation time (reflecting pore size), proton population and diffusion contrast, etc. PMID:15833623

  10. Two-dimensional dipolar nematic colloidal crystals.

    PubMed

    Skarabot, M; Ravnik, M; Zumer, S; Tkalec, U; Poberaj, I; Babic, D; Osterman, N; Musevic, I

    2007-11-01

    We study the interactions and directed assembly of dipolar nematic colloidal particles in planar nematic cells using laser tweezers. The binding energies for two stable configurations of a colloidal pair with homeotropic surface alignment are determined. It is shown that the orientation of the dipolar colloidal particle can efficiently be controlled and changed by locally quenching the nematic liquid crystal from the laser-induced isotropic phase. The interaction of a single colloidal particle with a single colloidal chain is determined and the interactions between pairs of colloidal chains are studied. We demonstrate that dipolar colloidal chains self-assemble into the two-dimensional (2D) dipolar nematic colloidal crystals. An odd-even effect is observed with increasing number of colloidal chains forming the 2D colloidal crystal. PMID:18233658