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Sample records for phase-coded uwb signal

  1. Attenuation characteristic of UWB signals propagation in free space

    NASA Astrophysics Data System (ADS)

    Li, Meng; Huang, Zhonghua

    2016-10-01

    Researching attenuation characteristic of UWB signals propagation in free-space is necessary for ultra-wideband (UWB) radio fuze optimized design. Research attenuation characteristic of UWB signals propagation in free space can be achieved by learning attenuation characteristic of radio waves propagation in free-space and UWB signal power spectral density. 50ps, 100ps and 200ps of pulse width UWB fuze transmission narrow pulse signal propagation in free-space are simulated and analyzed. The attenuation of UWB signals at 3m, 6m and 9m are contrasted. The simulation, analysis and contrast is theoretical basis of UWB radio fuze optimized design.

  2. Detection and Characterization of Phase-Coded Radar Signals

    DTIC Science & Technology

    2007-11-02

    Detection and Characterization of Phase-Coded Radar Signals 5c. PROGRAM ELEMENT NUMBER 5d. PROJECT NUMBER 5d. TASK NUMBER 6. AUTHOR( S ) Dr...Ernest R. Adams 5e. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME( S ) AND ADDRESS(ES) Cranfield University (RMCS) Shrivenham SN6 8LA United...Kingdom 8. PERFORMING ORGANIZATION REPORT NUMBER N/A 10. SPONSOR/MONITOR’S ACRONYM( S ) 9. SPONSORING/MONITORING AGENCY NAME( S ) AND

  3. UWB radar echo signal detection based on compressive sensing

    NASA Astrophysics Data System (ADS)

    Xia, Shugao; Sichina, Jeffrey; Liu, Fengshan

    2013-05-01

    Ultra-wideband (UWB) technology has been widely utilized in radar system because of the advantage of the ability of high spatial resolution and object-distinction capability. A major challenge in UWB signal processing is the requirement for very high sampling rate under Shannon-Nyquist sampling theorem which exceeds the current ADC capacity. Recently, new approaches based on the Finite Rate of Innovation (FRI) allow significant reduction in the sampling rate. A system for sampling UWB radar echo signal at an ultra-low sampling rate and the estimation of time-delays is presented in the paper. An ultra-low rate sampling scheme based on FRI is applied, which often results in sparse parameter extraction for UWB radar signal detection. The parameters such as time-delays are estimated using the framework of compressed sensing based on total-variation norm minimization. With this system, the UWB radar signal can be accurately reconstructed and detected with overwhelming probability at the rate much lower than Nyquist rate. The simulation results show that the proposed method is effective for sampling and detecting UWB radar signal at an ultra-low sampling rate.

  4. Demonstration of optical steganography transmission using temporal phase coded optical signals with spectral notch filtering.

    PubMed

    Hong, Xuezhi; Wang, Dawei; Xu, Lei; He, Sailing

    2010-06-07

    A novel approach is proposed and experimentally demonstrated for optical steganography transmission in WDM networks using temporal phase coded optical signals with spectral notch filtering. A temporal phase coded stealth channel is temporally and spectrally overlaid onto a public WDM channel. Direct detection of the public channel is achieved in the presence of the stealth channel. The interference from the public channel is suppressed by spectral notching before the detection of the optical stealth signal. The approach is shown to have good compatibility and robustness to the existing WDM network for optical steganography transmission.

  5. UWB doublet signal generation and modulation based on DFB laser under optical pulses injection

    NASA Astrophysics Data System (ADS)

    Chen, Dalei; Wang, Rong; Xiang, Peng; Pu, Tao; Fang, Tao; Zhou, Hua; Zhao, Jiyong; Huang, Long; Zhu, Huatao; Wang, Peng

    2016-05-01

    In this paper, a novel scheme to generate ultra-wideband (UWB) doublet signals based on the cross-gain modulation (XGM) effect in the DFB lasers is proposed and experimentally demonstrated, the modulation and transmission of the generated UWB doublet signals are also researched. In the proposed system, a gain-switched laser (GSL) is used as a master laser (ML) and the optical pulses from the ML are optically injected into two paralleled DFB lasers, which are used as slave lasers (SL). Then the outputs from the SLs are detected by a balanced photodiode (BPD) to generate the Bi-phased UWB signals. By properly setting the system parameters, UWB signals with various modulation formats such as on-off keying (OOK), pulse amplitude modulation (PAM) as well as the phase-shift keying (PSK) can be generated. In addition, fiber transmission of the modulated UWB signals is also experimentally investigated.

  6. Photonic generation of a phase-coded microwave signal based on a single dual-drive Mach-Zehnder modulator.

    PubMed

    Tang, Zhenzhou; Zhang, Tingting; Zhang, Fangzheng; Pan, Shilong

    2013-12-15

    A compact scheme for photonic generation of a phase-coded microwave signal using a dual-drive Mach-Zehnder modulator (DMZM) is proposed and experimentally demonstrated. In the proposed scheme, the radio frequency (RF) carrier and the coding signal are sent to the two RF ports of the DMZM, respectively. By properly setting the amplitude of the coding signal and the bias voltage of the DMZM, an exact π-phase-shift phase-coded microwave signal is generated. The proposed scheme has a simple structure since only a single DMZM is required. In addition, good frequency tunability is achieved because no frequency-dependent electrical devices or wavelength-dependent optical devices are applied. The feasibility of the proposed scheme is verified by experiment. 2 or 2.5 Gb/s phase-coded 10 and 20 GHz microwave signals are successfully generated.

  7. Generation of phase-coded microwave signals using a polarization-modulator-based photonic microwave phase shifter.

    PubMed

    Zhang, Yamei; Pan, Shilong

    2013-03-01

    A scheme for the generation of phase-coded microwave signals using an electrically tunable photonic microwave phase shifter is proposed and demonstrated. The photonic phase shifter is based on a single-sideband polarization modulator (PolM), and the tuning of the phase shifter is implemented by a second PolM. By introducing an RF signal to the first PolM and an electrical coding signal to the second PolM, a phase-coded microwave signal with binary phase codes or polyphase codes is achieved. An experiment is performed. The simple and flexible operation, high coding rate, large frequency range, excellent transmission performance, and high stability of the system is confirmed.

  8. Photonic generation of widely tunable phase-coded microwave signals based on a dual-parallel polarization modulator.

    PubMed

    Liu, Shifeng; Zhu, Dan; Wei, Zhengwu; Pan, Shilong

    2014-07-01

    A photonic approach for the generation of a widely tunable arbitrarily phase-coded microwave signal based on a dual-parallel polarization modulator (DP-PolM) is proposed and demonstrated without using any optical or electrical filter. Two orthogonally polarized ± first-order optical sidebands with suppressed carrier are generated based on the DP-PolM, and their polarization directions are aligned with the two principal axes of the following PolM. Phase coding is implemented at a following PolM driven by an electrical coding signal. The inherent frequency-doubling operation can make the system work at a frequency beyond the operation bandwidth of the DP-PolM and the 90° hybrid. Because no optical or electrical filter is applied, good frequency tunability is realized. An experiment is performed. The generation of phase-coded signals tuning from 10 to 40 GHz with up to 10  Gbit/s coding rates is verified.

  9. Performance of Multiple Pulse Multiple Delay Modulated UWB Signals in a Multiple Access Indoor Wireless Channel

    SciTech Connect

    Nekoogar, F

    2003-06-12

    In this paper, the performance of a two user UWB multiple access (UWB-MA) system based on multiple-pulse multiple-delay (MPMD) modulation scheme in an indoor wireless channel is evaluated by computer simulations. The indoor multipath propagation channel model used in this study is based on the modified statistical Saleh-Valenzuela model proposed by Foerester and Li from Intel. The simulation results indicate that the multipath performance of MPMD modulated signals in a multiple access system outperforms the nonmultipath case as the number of autocorrelation function (ACF) sampling points increases for each user. This is an unusual but important result, since MPMD receiver exploits multipath phenomenon in indoor wireless channels to increase the BER performance, hence the transmission rate in a UWB-MA system.

  10. Phase-coded microwave signal generation based on a single electro-optical modulator and its application in accurate distance measurement.

    PubMed

    Zhang, Fangzheng; Ge, Xiaozhong; Gao, Bindong; Pan, Shilong

    2015-08-24

    A novel scheme for photonic generation of a phase-coded microwave signal is proposed and its application in one-dimension distance measurement is demonstrated. The proposed signal generator has a simple and compact structure based on a single dual-polarization modulator. Besides, the generated phase-coded signal is stable and free from the DC and low-frequency backgrounds. An experiment is carried out. A 2 Gb/s phase-coded signal at 20 GHz is successfully generated, and the recovered phase information agrees well with the input 13-bit Barker code. To further investigate the performance of the proposed signal generator, its application in one-dimension distance measurement is demonstrated. The measurement accuracy is less than 1.7 centimeters within a measurement range of ~2 meters. The experimental results can verify the feasibility of the proposed phase-coded microwave signal generator and also provide strong evidence to support its practical applications.

  11. Super-resolution techniques for velocity estimation using UWB random noise radar signals

    NASA Astrophysics Data System (ADS)

    Dawood, Muhammad; Quraishi, Nafish; Alejos, Ana V.

    2011-06-01

    The Doppler spread pertaining to the ultrawideband (UWB) radar signals from moving target is directly proportional to the bandwidth of the transmitted signal and the target velocity. Using typical FFT-based methods, the estimation of true velocities pertaining to two targets moving with relatively close velocities within a radar range bin is problematic. In this paper, we extend the Multiple Signal Classification (MUSIC) algorithm to resolve targets moving velocities closer to each other within a given range bin for UWB random noise radar waveforms. Simulated and experimental results are compared for various target velocities using both narrowband (200MHz) and wideband (1GHz) noise radar signals, clearly establishing the unbiased and unambiguous velocity estimations using the MUSIC algorithm.

  12. Simulation and signal processing of through wall UWB radar for human being's periodic motions detection

    NASA Astrophysics Data System (ADS)

    Li, Jing; Liu, Fengshan; Xu, Penglong; Zeng, Zhaofa

    2013-05-01

    The human's Micro-Doppler signatures resulting from breathing, arm, foot and other periodic motion can provide valuable information about the structure of the moving parts and may be used for identification and classification purposes. In this paper, we carry out simulate with FDTD method and through wall experiment with UWB radar for human being's periodic motion detection. In addition, Advancements signal processing methods are presented to classify and to extract the human's periodic motion characteristic information, such as Micro-Doppler shift and motion frequency. Firstly, we apply the Principal Component Analysis (PCA) with singular value decomposition (SVD) to denoise and extract the human motion signal. Then, we present the results base on the Hilbert-Huang transform (HHT) and the S transform to classify and to identify the human's micro-Doppler shift characteristics. The results demonstrate that the combination of UWB radar and various processing methods has potential to detect human's Doppler signatures effectively.

  13. Model of human breathing reflected signal received by PN-UWB radar.

    PubMed

    Mabrouk, Mohamed; Rajan, Sreeraman; Bolic, Miodrag; Batkin, Izmail; Dajani, Hilmi R; Groza, Voicu Z

    2014-01-01

    Human detection is an integral component of civilian and military rescue operations, military surveillance and combat operations. Human detection can be achieved through monitoring of vital signs. In this article, a mathematical model of human breathing reflected signal received in PN-UWB radar is proposed. Unlike earlier published works, both chest and abdomen movements are considered for modeling the radar return signal along with the contributions of fundamental breathing frequency and its harmonics. Analyses of recorded reflected signals from three subjects in different postures and at different ranges from the radar indicate that ratios of the amplitudes of the harmonics contain information about posture and posture change.

  14. Experimental study of coexistence of multi-band OFDM-UWB and OFDM-baseband signals in long-reach PONs using directly modulated lasers.

    PubMed

    Morgado, José A P; Fonseca, Daniel; Cartaxo, Adolfo V T

    2011-11-07

    Transmission of coexisting Orthogonal Frequency Division Multiplexing (OFDM)-baseband (BB) and multi-band OFDM-ultra-wideband (UWB) signals along long-reach passive optical networks using directly modulated lasers (DML) is experimentally demonstrated.When optimized modulation indexes are used, bit error ratios not exceeding 5 × 10⁻⁴ can be achieved by all (OFDM-BB and three OFDM-UWB sub-bands) signals for a reach of 100 km of standard single-mode fiber (SSMF) and optical signal-to-noise ratios not lower than 25dB@0.1 nm. It is experimentally shown that, for the SSMF reach of 100km, the optimized performance of coexisting OFDM-BB and OFDM-UWB signals is mainly imposed by the combination of two effects: the SSMF dispersion-induced nonlinear distortion of the OFDM-UWB signals caused by the OFDM-BB and OFDM-UWB signals, and the further degradation of the OFDM-UWB signals with higher frequency, due to the reduced DML bandwidth.

  15. Transmission improvement due to pre-emphasis of multi-band OFDM-UWB signals in LR-PONs using directly modulated lasers

    NASA Astrophysics Data System (ADS)

    Fonseca, Daniel; Morgado, José A. P.; Cartaxo, Adolfo V. T.

    2014-03-01

    The transmission improvement obtained through the usage of pre-emphasis (PE) of single-band and multi-band orthogonal frequency division multiplexing (OFDM) ultra-wideband (UWB) signals using directly modulated lasers (DML) along long-reach passive optical networks is experimentally evaluated. Additionally, OFDM-UWB sub-bands with central frequencies above the cut-off frequency of the DML are experimentally considered in order to evaluate extending the transmission capacity through the usage of PE. In case of single-band transmission, PE improves the bit error ratio (BER) of several OFDM-UWB sub-bands by more than two orders of magnitude in back-to-back conditions as well as after transmission along 100 km of standard single-mode fiber transmission (SSMF). Such improvement is limited by the reduced intensity modulation response variation of the DML within the passband of each OFDM-UWB sub-band, as fixed modulation index is considered in all tested cases. Considering multi-band transmission along 100 km of SSMF, PE allows doubling the number of transmitted sub-bands before a BER exceeding ? is achieved for any of the sub-bands and an optical signal-to-noise ratio of 25 dB?0.1 nm. Such improvement is obtained as PE changes the effective modulation depth of each transmitted OFDM-UWB sub-band, so that equalized signal power after detection and almost identical BER in all OFDM-UWB sub-bands occur.

  16. Time Reversal for Ultra-wideband (UWB) Sensor Networking

    DTIC Science & Technology

    2007-07-31

    allocated by the FCC for UWB communications suggests a bandpass signal. Also, this pulse shape allows multi - band modulation, in which multiple frequency... bands are used to efficiently occupy the UWB spectrum. Multiple UWB signals can be transmitted at the same 16 (a) (b) Figure 2.4 Gaussian pulse : (a) in...ects, an analysis of the virtual array, single-user and multi -user time reversal UWB -MIMO system performance, and a comparison with time reversal UWB

  17. UWB communication receiver feedback loop

    DOEpatents

    Spiridon, Alex; Benzel, Dave; Dowla, Farid U.; Nekoogar, Faranak; Rosenbury, Erwin T.

    2007-12-04

    A novel technique and structure that maximizes the extraction of information from reference pulses for UWB-TR receivers is introduced. The scheme efficiently processes an incoming signal to suppress different types of UWB as well as non-UWB interference prior to signal detection. Such a method and system adds a feedback loop mechanism to enhance the signal-to-noise ratio of reference pulses in a conventional TR receiver. Moreover, sampling the second order statistical function such as, for example, the autocorrelation function (ACF) of the received signal and matching it to the ACF samples of the original pulses for each transmitted bit provides a more robust UWB communications method and system in the presence of channel distortions.

  18. A hybrid TOA-fingerprinting based localization of mobile nodes using UWB signaling for Non-line-of-sight conditions.

    PubMed

    Kabir, Md Humayun; Kohno, Ryuji

    2012-01-01

    Recently, Impulse Radio Ultra Wideband (IR-UWB) signaling has become popular for providing precise location accuracy for mobile and wireless sensor node localization in the indoor environment due to its large bandwidth and high time resolution while providing ultra-high transmission capacity. However, the Non-line-of-sight (NLOS) error mitigation has considerable importance in localization of wireless nodes. In order to mitigate NLOS errors in indoor localization this paper proposes and investigates a novel approach which creates a hybrid combination of channel impulse response (CIR)-based fingerprinting (FP) positioning and an iterative Time of Arrival (TOA) real time positioning method using Ultra Wideband (UWB) signaling. Besides, to reduce the calculation complexities in FP method, this paper also introduces a unique idea for the arrangement of reference nodes (or tags) to create a fingerprinting database. The simulation results confirm that the proposed hybrid method yields better positioning accuracies and is much more robust in NLOS error mitigation than TOA only and FP only and a conventional iterative positioning method.

  19. A human body model for efficient numerical characterization of UWB signal propagation in wireless body area networks.

    PubMed

    Lim, Hooi Been; Baumann, Dirk; Li, Er-Ping

    2011-03-01

    Wireless body area network (WBAN) is a new enabling system with promising applications in areas such as remote health monitoring and interpersonal communication. Reliable and optimum design of a WBAN system relies on a good understanding and in-depth studies of the wave propagation around a human body. However, the human body is a very complex structure and is computationally demanding to model. This paper aims to investigate the effects of the numerical model's structure complexity and feature details on the simulation results. Depending on the application, a simplified numerical model that meets desired simulation accuracy can be employed for efficient simulations. Measurements of ultra wideband (UWB) signal propagation along a human arm are performed and compared to the simulation results obtained with numerical arm models of different complexity levels. The influence of the arm shape and size, as well as tissue composition and complexity is investigated.

  20. TDM-PON compatible generation of 10 Gbps NRZ and 1.25 Gbps UWB signals by a single light source.

    PubMed

    Malekizandi, Mohammadreza; Le, Quang Trung; Emsia, Ali; Briggmann, Dieter; Chipouline, Arkadi; Küppers, Franko

    2016-07-25

    A novel and cost-efficient technique is presented to generate non-return-to-zero (NRZ) and ultra-wideband (UWB) signals in different time slots of time division multiplexing-passive optical network (TDM-PON) by using a single chirped controlled semiconductor laser associated with an optical bandpass filter. In this technique, the chirp of the laser is controlled by different bias burst amplitudes (BBA) for different time slots. Through the proper selection of the burst amplitudes, 10 Gbps NRZ and 1.25 Gbps UWB signals are generated in different time slots. Principle of operation is discussed, the complete chirp behavior of the laser is experimentally investigated, data transmission of the generated signals is demonstrated and bit-error-rate (BER) level of 10-9 is achieved.

  1. UWB transmitter

    SciTech Connect

    Dallum, Gregory E.; Pratt, Garth C.; Haugen, Peter C.; Romero, Carlos E.

    2013-01-15

    An ultra-wideband (UWB) dual impulse transmitter is made up of a trigger edge selection circuit actuated by a single trigger input pulse; a first step recovery diode (SRD) based pulser connected to the trigger edge selection circuit to generate a first impulse output; and a second step recovery diode (SRD) based pulser connected to the trigger edge selection circuit in parallel to the first pulser to generate a second impulse output having a selected delay from the first impulse output.

  2. UWB pulse propagation into human tissues

    NASA Astrophysics Data System (ADS)

    Cavagnaro, Marta; Pittella, Erika; Pisa, Stefano

    2013-12-01

    In this paper the propagation of a UWB pulse into a layered model of the human body is studied to characterize absorption and reflection of the UWB signal due to the different body tissues. Several time behaviours for the incident UWB pulse are considered and compared with reference to the feasibility of breath and heartbeat activity monitoring. Results show that if the UWB source is placed far from the human body, the reflection coming from the interface between air and skin can be used to detect the respiratory activity. On the contrary, if the UWB source is placed close to the human body, a small reflection due to the interface between the posterior lung wall and the bone, which is well distanced in time from the reflections due to the first layers of the body model, can be used to detect lung and heart changes associated with the cardio-respiratory activity.

  3. A UWB Radar Signal Processing Platform for Real-Time Human Respiratory Feature Extraction Based on Four-Segment Linear Waveform Model.

    PubMed

    Hsieh, Chi-Hsuan; Chiu, Yu-Fang; Shen, Yi-Hsiang; Chu, Ta-Shun; Huang, Yuan-Hao

    2016-02-01

    This paper presents an ultra-wideband (UWB) impulse-radio radar signal processing platform used to analyze human respiratory features. Conventional radar systems used in human detection only analyze human respiration rates or the response of a target. However, additional respiratory signal information is available that has not been explored using radar detection. The authors previously proposed a modified raised cosine waveform (MRCW) respiration model and an iterative correlation search algorithm that could acquire additional respiratory features such as the inspiration and expiration speeds, respiration intensity, and respiration holding ratio. To realize real-time respiratory feature extraction by using the proposed UWB signal processing platform, this paper proposes a new four-segment linear waveform (FSLW) respiration model. This model offers a superior fit to the measured respiration signal compared with the MRCW model and decreases the computational complexity of feature extraction. In addition, an early-terminated iterative correlation search algorithm is presented, substantially decreasing the computational complexity and yielding negligible performance degradation. These extracted features can be considered the compressed signals used to decrease the amount of data storage required for use in long-term medical monitoring systems and can also be used in clinical diagnosis. The proposed respiratory feature extraction algorithm was designed and implemented using the proposed UWB radar signal processing platform including a radar front-end chip and an FPGA chip. The proposed radar system can detect human respiration rates at 0.1 to 1 Hz and facilitates the real-time analysis of the respiratory features of each respiration period.

  4. All-optical UWB generation and modulation using SOA-XPM effect and DWDM-based multi-channel frequency discrimination.

    PubMed

    Wang, Fei; Dong, Jianji; Xu, Enming; Zhang, Xinliang

    2010-11-22

    An all-optical UWB pulses generation and modulation scheme using cross phase modulation (XPM) effect of semiconductor optical amplifier (SOA) and DWDM-based multi-channel frequency discrimination is proposed and demonstrated, which has potential application in multiuser UWB-Over-Fiber communication systems. When a Gaussian pulse light and a wavelength-tunable CW probe light are together injected into the SOA, the probe light out from the SOA will have a temporal chirp due to SOA-XPM effect. When the chirped probe light is tuned to the slopes of single DWDM channel transmittance curve, the optical phase modulation to intensity modulation conversion is achieved at DWDM that serves as a multi-channel frequency discriminator, the inverted polarity Gaussian monocycle and doublet pulse is detected by a photodetector, respectively. If the probe lights are simultaneously aimed to different slopes of several DWDM channels, multi-channel or binary-phase-coded UWB signal generation can be acquired. Using proposed scheme, pulse amplitude modulation (PAM), pulse polarity modulation (PPM) and pulse shape modulation (PSM) to UWB pulses also can be conveniently realized.

  5. Pulse compression using binary phase codes

    NASA Technical Reports Server (NTRS)

    Farley, D. T.

    1983-01-01

    In most MST applications pulsed radars are peak power limited and have excess average power capacity. Short pulses are required for good range resolution, but the problem of range ambiguity (signals received simultaneously from more than one altitude) sets a minimum limit on the interpulse period (IPP). Pulse compression is a technique which allows more of the transmitter average power capacity to be used without sacrificing range resolution. As the name implies, a pulse of power P and duration T is in a certain sense converted into one of power nP and duration T/n. In the frequency domain, compression involves manipulating the phases of the different frequency components of the pulse. One way to compress a pulse is via phase coding, especially binary phase coding, a technique which is particularly amenable to digital processing techniques. This method, which is used extensively in radar probing of the atmosphere and ionosphere is discussed. Barker codes, complementary and quasi-complementary code sets, and cyclic codes are addressed.

  6. MRI-aided tissues interface characterization: An accurate signal propagation time calculation method for UWB breast tumor imaging

    NASA Astrophysics Data System (ADS)

    Wang, Liang; Xiao, Xia; Kikkawa, Takamaro

    2016-12-01

    Radar-based ultrawideband (UWB) microwave imaging is expected to be a safe, low-cost tool for breast cancer detection. However, since radar wave travels at different speeds in different tissues, propagation time is hard to be estimated in heterogeneous breast. Wrongly estimated propagation time leads to error of tumor location in resulting image, aka imaging error. In this paper, we develop a magnetic resonance imaging-aided (MRI-aided) propagation time calculation technique which is independent from radar imaging system but can help decrease the imaging error. The technique can eliminate the influence of the rough interface between fat layer and gland layer in breast and get relative accurate thicknesses of two layers. The propagation time in each layer is calculated and summed. The summed propagation time is used in Confocal imaging algorithm to increase the accuracy of resulting image. 25 patients' breast models with glands of varying size are classified into four categories for imaging simulation tests. Imaging accuracy in terms of tumor location along x-direction has been improved for 21 among 25 cases, as a result, overall around 50% improvement compared to conventional UWB imaging.

  7. UWB Radio Link Modeling for Multipath Environment

    NASA Astrophysics Data System (ADS)

    Uguen, B.; Talom, F. T.; Chassay, G.

    Ultra-wideband (UWB) systems have the potential to provide very high data rates over short distances. This paper details the construction of the received signal from a pulse waveform on the transmission line at the transmitter to the received signal at the receiver allowing a fine analysis of antennas impact on UWB systems. This is used for deterministic modeling based on ray tracing (RT) and geometrical optics (GO). The paper presents the way of sizing the pulse amplitude in order to satisfy a given power spectral density (PSD) mask for a given modulation. The proposed approach is demonstrated to be coherent with classical power link budget.

  8. Intruder detection and tracking using UWB technology

    NASA Astrophysics Data System (ADS)

    Schiavone, Guy A.; Wahid, Parveen; Palaniappan, Ravishankar; Tracy, Judd; Vandoorn, Eric; Micikevicius, Paulis; Hughes, Charles

    2004-08-01

    UWB communication is essentially the transmission and receiving of ultra short electromagnetic energy pulses. Short pulses mean wide bandwidths, often greatly exceeding 25% of the nominal center frequency. Modern UWB radio is characterized by very low power transmission (in the range of tens of microwatts) and wide bandwidths (greater than a gigahertz). One of the major applications of Ultra-wide band technology has been for detection and tracking of intruders in different environments. Based on some of our previous work [1,2] we developed a hybrid Ray-tracing/FDTD technique to study the indoor and outdoor propagation of UWB signals. The basic goal of this paper is to describe the experimental and simulation studies that were conducted to locate and track an intruder inside a UWB sensor web system. The sensor was developed using the Time Domain P-200 device and the software was developed using MATLAB. Return scans from UWB devices are analyzed to determine the noise floor and the signal strength. Using the noise floor level a threshold level is set above which the alarm will be triggered to determine the presence of an intruder. The probability of false alarm (PFA) is also determined using the Signal-to-Noise ratio and the threshold. We vary the PFA to lower the false alarm to a minimum level. We also determine the noise statistics of the system using Non-parametric Kolmogorov-Smirnov (KS) test. Using this basic UWB sensor web system we will try to determine the physical dimensions of the intruder and also track multiple intruders on the system.

  9. UWB delay and multiply receiver

    DOEpatents

    Dallum, Gregory E.; Pratt, Garth C.; Haugen, Peter C.; Romero, Carlos E.

    2013-09-10

    An ultra-wideband (UWB) delay and multiply receiver is formed of a receive antenna; a variable gain attenuator connected to the receive antenna; a signal splitter connected to the variable gain attenuator; a multiplier having one input connected to an undelayed signal from the signal splitter and another input connected to a delayed signal from the signal splitter, the delay between the splitter signals being equal to the spacing between pulses from a transmitter whose pulses are being received by the receive antenna; a peak detection circuit connected to the output of the multiplier and connected to the variable gain attenuator to control the variable gain attenuator to maintain a constant amplitude output from the multiplier; and a digital output circuit connected to the output of the multiplier.

  10. UWB dual burst transmit driver

    SciTech Connect

    Dallum, Gregory E; Pratt, Garth C; Haugen, Peter C; Zumstein, James M; Vigars, Mark L; Romero, Carlos E

    2012-04-17

    A dual burst transmitter for ultra-wideband (UWB) communication systems generates a pair of precisely spaced RF bursts from a single trigger event. An input trigger pulse produces two oscillator trigger pulses, an initial pulse and a delayed pulse, in a dual trigger generator. The two oscillator trigger pulses drive a gated RF burst (power output) oscillator. A bias driver circuit gates the RF output oscillator on and off and sets the RF burst packet width. The bias driver also level shifts the drive signal to the level that is required for the RF output device.

  11. UWB Tracking Algorithms: AOA and TDOA

    NASA Technical Reports Server (NTRS)

    Ni, Jianjun David; Arndt, D.; Ngo, P.; Gross, J.; Refford, Melinda

    2006-01-01

    Ultra-Wideband (UWB) tracking prototype systems are currently under development at NASA Johnson Space Center for various applications on space exploration. For long range applications, a two-cluster Angle of Arrival (AOA) tracking method is employed for implementation of the tracking system; for close-in applications, a Time Difference of Arrival (TDOA) positioning methodology is exploited. Both AOA and TDOA are chosen to utilize the achievable fine time resolution of UWB signals. This talk presents a brief introduction to AOA and TDOA methodologies. The theoretical analysis of these two algorithms reveal the affecting parameters impact on the tracking resolution. For the AOA algorithm, simulations show that a tracking resolution less than 0.5% of the range can be achieved with the current achievable time resolution of UWB signals. For the TDOA algorithm used in close-in applications, simulations show that the (sub-inch) high tracking resolution is achieved with a chosen tracking baseline configuration. The analytical and simulated results provide insightful guidance for the UWB tracking system design.

  12. Trellis phase codes for power-bandwith efficient satellite communications

    NASA Technical Reports Server (NTRS)

    Wilson, S. G.; Highfill, J. H.; Hsu, C. D.; Harkness, R.

    1981-01-01

    Support work on improved power and spectrum utilization on digital satellite channels was performed. Specific attention is given to the class of signalling schemes known as continuous phase modulation (CPM). The specific work described in this report addresses: analytical bounds on error probability for multi-h phase codes, power and bandwidth characterization of 4-ary multi-h codes, and initial results of channel simulation to assess the impact of band limiting filters and nonlinear amplifiers on CPM performance.

  13. A Minimized MIMO-UWB Antenna with High Isolation and Triple Band-Notched Functions

    NASA Astrophysics Data System (ADS)

    Kong, Yuanyuan; Li, Yingsong; Yu, Kai

    2016-11-01

    A compact high isolation MIMO-UWB antenna with triple frequency rejection bands is proposed for UWB communication applications. The proposed MIMO-UWB antenna consists of two identical UWB antennas and each antenna element has a semicircle ring shaped radiation patch fed by a bend microstrip feeding line for covering the UWB band, which operates from 2.85 GHz to 11.79 GHz with an impedance bandwidth of 122.1 %. By etching a L-shaped slot on the ground plane, and embedding an "anchor" shaped stub into the patch and integrating an open ring under the semicircle shaped radiation patch, three notch bands are realized to suppress WiMAX (3.3-3.6 GHz), WLAN(5.725-5.825 GHz) and uplink of X-band satellite (7.9-8.4 GHz) signals. The high isolation with S21<-20 dB in most UWB band is obtained by adding a protruded decoupling structure. The design procedure of the MIMO-UWB antenna is given in detail. The proposed MIMO-UWB antenna is simulated, fabricated and measured. Experimental results demonstrate that the proposed MIMO-UWB antenna has a stable gain, good impedance match, high isolation, low envelope correlation coefficient and good radiation pattern at the UWB operating band and it can provide three designated notch bands.

  14. An adaptive line enhancement method for UWB proximity fuze signal processing based on correlation matrix estimation with time delay factor

    NASA Astrophysics Data System (ADS)

    Li, Meng; Huang, Zhonghua

    2016-10-01

    Signal processing for an ultra-wideband radio fuze receiver involves some challenges: it requires high real-time performance; the output signal is mixed with broadband noise; and the signal-to-noise ratio (SNR) decreases with increased detection range. The adaptive line enhancement method is used to filter the output signal of the ultra-wideband radio fuze receiver, and thus suppress the wideband noise from the output signal of the receiver and extract the target characteristic signal. The filter input correlation matrix estimation algorithm is based on the delay factor of an adaptive line enhancer. The proposed adaptive algorithm was used to filter and reduce noise in the output signal from the fuze receiver. Simulation results showed that the SNR of the output signal after adaptive noise reduction was improved by 20 dB, which was higher than the SNR of the output signal after finite impulse response (FIR) filtering of around 10 dB.

  15. UWB Tracking Software Development

    NASA Technical Reports Server (NTRS)

    Gross, Julia; Arndt, Dickey; Ngo, Phong; Phan, Chau; Dusl, John; Ni, Jianjun; Rafford, Melinda

    2006-01-01

    An Ultra-Wideband (UWB) two-cluster Angle of Arrival (AOA) tracking prototype system is currently being developed and tested at NASA Johnson Space Center for space exploration applications. This talk discusses the software development efforts for this UWB two-cluster AOA tracking system. The role the software plays in this system is to take waveform data from two UWB radio receivers as an input, feed this input into an AOA tracking algorithm, and generate the target position as an output. The architecture of the software (Input/Output Interface and Algorithm Core) will be introduced in this talk. The development of this software has three phases. In Phase I, the software is mostly Matlab driven and calls C++ socket functions to provide the communication links to the radios. This is beneficial in the early stage when it is necessary to frequently test changes in the algorithm. Phase II of the development is to have the software mostly C++ driven and call a Matlab function for the AOA tracking algorithm. This is beneficial in order to send the tracking results to other systems and also to improve the tracking update rate of the system. The third phase is part of future work and is to have the software completely C++ driven with a graphics user interface. This software design enables the fine resolution tracking of the UWB two-cluster AOA tracking system.

  16. Range sidelobe reduction for the random binary phase codes

    NASA Astrophysics Data System (ADS)

    Gu, Hong; Liu, Guosui; Sun, Guangmin; Li, Xi; Su, Weimin

    1997-06-01

    Based on the statistics theory and the pulse compression technique, a statistical method of reducing the range sidelobe (RSL) of the random binary phase codes (RBPC) is presented, which is different from those of decreasing the RSL of the pseudorandom binary phase codes. The theoretical analysis and computer simulation show that it is possible to suppress the peak RSL to lower than -30 dB, which can effectively guarantee the RBPC radar with good electronic counter-countermeasures feature applicable. Additionally, owing to the Doppler of the target, the maximum loss of the ratio of the mainlobe and sidelobe (MSR) is also discussed. In the meantime, the approach to realization of the RSL reduction with digital signal processors is given.

  17. UWB technology for safety-oriented vehicular communications

    NASA Astrophysics Data System (ADS)

    Llorente, Roberto; Morant, Maria

    2016-03-01

    Ultra-Wide Band (UWB) technology for wireless multiple access communications are receiving great interest for the last five years due to its unique features such as spectrum coexistence with other wireless services, RF front-end simplicity (enabling potential low cost terminals), good radio wave propagation (robust against multi-path fading, material penetration) and high bitrate. Low-cost UWB technology can be employed to provide simultaneous communications and vehicular radar capabilities. In this paper, the application of vehicle-to-vehicle (C2C), infrastructure-to-vehicle (I2C), communication and vehicular radar (VRAD) based on UWB technology are proposed altogether the required fiber-optics infrastructure, with the advantage of being flexible, cost-effective, reliable, fast and secure. The experimental validation and comparison for the optical generation of UWB signals combined with radio-over-fiber transmission is also reported in this work applied to vehicular communications. Both impulse-radio (IR-UWB) and orthogonal frequency division multiplexing (OFDM-UWB) signals are generated and their performance are evaluated experimentally in the 3.1-10.6 GHz frequency range. Up-conversion in the 60 GHz wireless band is also herein reported.

  18. Time-Reversal Based Range Extension Technique for Ultra-Wideband (UWB) Sensors and Applications in Tactical Communications and Networking

    DTIC Science & Technology

    2008-01-16

    UWB modulation pulse waveform-software defined or cognitive. From a information-theoreticalIa viewpoint, the two parts, as a whole, form so-called "pre...34Physics-Based Pulse Distortion for Ultra-Wideband Signals," IEEE Trans. Veh. Tech., vol. 54, September 2005. [14] A. Molisch, "Status of models for UWB ...detect these 12 pulses . The key advantage of transient UWB pulses over the narrowband, sinusoidal signals is that the former can be resolvable in time, to

  19. Performance comparison between UWB-IR and MB-OFDM with transmit diversity in implant communications.

    PubMed

    Shimizu, Yuto; Furukawa, Tomofumi; Anzai, Daisuke; Wang, Jianqing

    2015-01-01

    An ultra wideband (UWB) technology is a potential candidate for implant body area networks (BANs), where wireless communications are established between inside and outside of a human body. The UWB can accomplish higher data rate than the other frequency band for the implant communication. However, due to its high frequencies, the UWB signals suffer from quite large attenuation in the implant communication link, which makes it difficult to achieve reliable communications. For achieving reliable communication, it is well known that a spatial diversity technique is efficient without any frequency extension. In our previous works, we developed a transmit polarization diversity antenna for the UWB implant communication. However, optimal UWB modulation scheme for transmit diversity were rarely discussed. In this paper, in order to investigate the optimal UWB modulation schemes for implant communication with transmit diversity, we compare the communication performances of UWB-impulse radio (UWB-IR) and multiband-orthogonal frequency division multiplexing (MB-OFDM). For this purpose, we first analyze the propagation characteristics in the implant UWB channel, which ranges from 3.4 GHz to 4.8 GHz, using a finite difference time domain (FDTD) numerical analysis technique. Then, we evaluate and discuss the communication performances of both modulation schemes for the transmit polarization diversity from the viewpoint of the BER and the required transmit power.

  20. UWB microwave breast cancer detection: generalized models and performance prediction.

    PubMed

    Chen, Yifan; Gunawan, Erry; Kim, Yongmin; Low, Kay Soon; Soh, Cheong Boon; Thi, Lin Lin

    2006-01-01

    This paper presents a generic framework for the modeling of ultra-wideband (UWB) signal propagation in human breast, which facilitates system-level simulations and provides performance prediction. The clutter associated with the breast tissue heterogeneity is modeled through several key parameters depending on the tissue compositions. Subsequently, important channel properties such as the backscatter energy and the probability density function of time-of-arrival are derived. The modified Hermite polynomials, which fit well into the real pulse shapes, are then used to model the UWB signals. Armed with the channel/signal model preliminaries, three metrics are proposed, namely, the mean clutter response, the clean tumor response, and the worst-case clutter response. The generalized model provides a parsimonious way to study the effects of tissue structures, pulse templates, and array setup on the performance of a specified UWB imaging system. Numerical examples are used to demonstrate the usefulness of the proposed approach.

  1. UWB Tracking System Design for Lunar/Mars Exploration

    NASA Technical Reports Server (NTRS)

    Ni, Jianjun; Arndt, Dickey; Ngo, Phong; Phan, Chau; Gross, Julia

    2006-01-01

    This paper describes a design effort for a prototype ultra-wideband (UWB) tracking system that is currently under development at NASA Johnson Space Center (JSC). The system is being studied for use in tracking of lunar/Mars rovers during early exploration missions when satellite navigation systems are not available. The UWB technology is exploited to implement the tracking system due to its properties such as high data rate, fine time resolution, low power spectral density, and multipath immunity. A two-cluster prototype design using commercially available UWB products is proposed to implement the Angle Of Arrival (AOA) tracking methodology in this research effort. An AOA technique using the Time Difference Of Arrival (TDOA) information is utilized for location estimation in the prototype system, not only to exploit the precise time resolution possible with UWB signals, but also to eliminate the need for synchronization between the transmitter and the receiver. After the UWB radio at each cluster is used to obtain the TDOA estimates from the UWB signal sent from the target, the TDOA data is converted to AOA data to find the angle of arrival, assuming this is a far field application. Since the distance between two clusters is known, the target position is computed by a simple triangulation. Simulations show that the average tracking error at a range of 610 meters is 2.7595 meters, less than 0.5% of the tracking range. Outdoor tests to track the SCOUT vehicle (The Science Crew Operations and Utility Testbed) near the Meteor Crater, Flagstaff, Arizona were performed on September 12-13, 2005. The tracking performance was obtained with less than 1% tracking error at ranges up to 2000 feet. No RF interference with on-board GPS, video, voice and telemetry systems was detected. Outdoor tests demonstrated the UWB tracking capability.

  2. Accurate TOA-Based UWB Localization System in Coal Mine Based on WSN

    NASA Astrophysics Data System (ADS)

    Cheng, Guangliang

    Over the last years, there has been a great deal of interest in Ultra Wideband (UWB) wireless communication and Wireless Sensor Networks(WSN), especially following the proposing of the internet of things by the MIT (Massachusetts Institute of Technology) in 1999, hich is also result in an increasing research on UWB and WSN applications. This article mainly introduced the accurate UWB Localization System based on WSN in coal mine. Firstly, we briefly introduced UWB and WSN Localization technology. Secondly, the advantages and disadvantages of the previous personnel localization technology in coal mine was analyzed and contrasted, and then the suitable personnel localization system in coal mine based on UWB signal and TOA estimate positioning scheme are presented. At last the rationality and feasibility of this scheme was proved through the simulation results.

  3. Method of remote powering and detecting multiple UWB passive tags in an RFID system

    DOEpatents

    Dowla, Farid U [Castro Valley, CA; Nekoogar, Faranak [San Ramon, CA; Benzel, David M [Livermore, CA; Dallum, Gregory E [Livermore, CA; Spiridon, Alex [Palo Alto, CA

    2012-05-29

    A new Radio Frequency Identification (RFID), tracking, powering apparatus/system and method using coded Ultra-wideband (UWB) signaling is introduced. The proposed hardware and techniques disclosed herein utilize a plurality of passive UWB transponders in a field of an RFID-radar system. The radar system itself enables multiple passive tags to be remotely powered (activated) at about the same time frame via predetermined frequency UWB pulsed formats. Once such tags are in an activated state, an UWB radar transmits specific "interrogating codes" to put predetermined tags in an awakened status. Such predetermined tags can then communicate by a unique "response code" so as to be detected by an UWB system using radar methods.

  4. Ultra Wideband (UWB) communication vulnerability for security applications.

    SciTech Connect

    Cooley, H. Timothy

    2010-07-01

    RF toxicity and Information Warfare (IW) are becoming omnipresent posing threats to the protection of nuclear assets, and within theatres of hostility or combat where tactical operation of wireless communication without detection and interception is important and sometimes critical for survival. As a result, a requirement for deployment of many security systems is a highly secure wireless technology manifesting stealth or covert operation suitable for either permanent or tactical deployment where operation without detection or interruption is important The possible use of ultra wideband (UWB) spectrum technology as an alternative physical medium for wireless network communication offers many advantages over conventional narrowband and spread spectrum wireless communication. UWB also known as fast-frequency chirp is nonsinusoidal and sends information directly by transmitting sub-nanosecond pulses without the use of mixing baseband information upon a sinusoidal carrier. Thus UWB sends information using radar-like impulses by spreading its energy thinly over a vast spectrum and can operate at extremely low-power transmission within the noise floor where other forms of RF find it difficult or impossible to operate. As a result UWB offers low probability of detection (LPD), low probability of interception (LPI) as well as anti-jamming (AJ) properties in signal space. This paper analyzes and compares the vulnerability of UWB to narrowband and spread spectrum wireless network communication.

  5. Deceptive jamming for countering UWB-SAR based on Doppler frequency phase template of false target

    NASA Astrophysics Data System (ADS)

    He, Xiaodong; Tang, Bin

    2016-04-01

    A false target deceptive jamming method for countering ultra-wideband synthetic aperture radar (UWB-SAR) is proposed in this paper, which is based on dechirp processing to intercepted UWB-SAR signal and inverse dechirp to jamming signal. The jammer quadrature down-converts and dechirps the intercepted UWB-SAR signal using a linear frequency modulation (LFM) signal oscillator, which could reduce the bandwidth and sample rate of analog-to-digital converter. Then, the jammer utilises the azimuth direction Doppler frequency phase between the false target and the jammer, and backward reflection coefficient template to modulate the phase of the intercepted UWB-SAR signal, and then delayed the modulated phase and also modulated the range direction Doppler frequency phase to the that. Finally, the jammer uses LFM signal oscillator to up-convert the narrowband jamming signal in order to recover the bandwidth of the signal. Parameter errors analysis and simulation results have shown that the detected parameters and motion characteristic errors reduce the resolution and offset the expected position of the false target, but it still could obtain an expected false target image. Theoretical analysis and simulation results indicated that the jamming signal proposed in this paper could produce a false target in the UWB-SAR image, which provide a feasible method for countering UWB-SAR in real time.

  6. Spectral efficiency considerations in ultrawideband (UWB) radar and communications

    NASA Astrophysics Data System (ADS)

    Rao, Chinmay; Narayanan, Ram M.

    2005-05-01

    Recent years have seen a rapid expansion of ultrawideband (UWB) technology in radar and communications applications. While the initial impetus for UWB systems was derived from the need for high-resolution radar applications for the military, these systems are now used in a variety of consumer applications such as cellular phones and satellite television. The principal motivation for using UWB is that it offers improved spectral efficiency, i.e., it permits multiple users to occupy and operate within the same frequency band with minimal cross-interference. Currently, UWB schemes use some form of pulse train modulation to encode data onto the carrier. However, these schemes are not always ideal since: (a) these are not the most spectrally efficient due to the fact that additional users can be added by using alternate schemes, (b) these do not possess anti-jam capability since it is possible to estimate the carrier frequency the signal, and (c) such type of modulation possess frequency sidelobes that might interfere with UWB devices in adjacent bands. Our research aims to characterize the above shortcomings and to ultimately develop a method for defining and estimating an appropriate spectral efficiency metric. We also present results of our study of new waveform designs, for both radar and communications, resulting in optimal sharing of frequency segments with minimum impact to system functionality and avoidance of spectral fratricide. One such waveform investigated and described herein is a combination of pulse shape and pulse position modulation, primarily for optimizing the performance of UWB communications systems that use pulse trains.

  7. A High-Voltage UWB Coupled-Line Directional Coupler for Radar

    NASA Astrophysics Data System (ADS)

    Farr, Everett G.; Atchley, Lanney M.; Ellibee, Donald E.; Lawry, Dean I.

    The simplest method of building ultra-wideband (UWB) radar systems requires two antennas, one each for transmission and reception. To save space, it would be preferable to use a single antenna, so a UWB, high-voltage directional coupler is needed. In support of that goal, we develop here coupled-line directional couplers. We begin by describing the time-domain theory of operation of such couplers, and we optimize the impedances for maximum return signal. We then design, build and test two versions of high-voltage coupled-line directional couplers. We incorporate the directional couplers into a low-voltage UWB radar system, and we observe scattering back from a comer reflector. We identify possible improvements to the directional couplers and the UWB radar system.

  8. Waveform Analysis of UWB GPR Antennas.

    PubMed

    Rial, Fernando I; Lorenzo, Henrique; Pereira, Manuel; Armesto, Julia

    2009-01-01

    Ground Penetrating Radar (GPR) systems fall into the category of ultra-wideband (UWB) devices. Most GPR equipment covers a frequency range between an octave and a decade by using short-time pulses. Each signal recorded by a GPR gathers a temporal log of attenuated and distorted versions of these pulses (due to the effect of the propagation medium) plus possible electromagnetic interferences and noise. In order to make a good interpretation of this data and extract the most possible information during processing, a deep knowledge of the wavelet emitted by the antennas is essential. Moreover, some advanced processing techniques require specific knowledge of this signal to obtain satisfactory results. In this work, we carried out a series of tests in order to determine the source wavelet emitted by a ground-coupled antenna with a 500 MHz central frequency.

  9. Waveform Analysis of UWB GPR Antennas

    PubMed Central

    Rial, Fernando I.; Lorenzo, Henrique; Pereira, Manuel; Armesto, Julia

    2009-01-01

    Ground Penetrating Radar (GPR) systems fall into the category of ultra-wideband (UWB) devices. Most GPR equipment covers a frequency range between an octave and a decade by using short-time pulses. Each signal recorded by a GPR gathers a temporal log of attenuated and distorted versions of these pulses (due to the effect of the propagation medium) plus possible electromagnetic interferences and noise. In order to make a good interpretation of this data and extract the most possible information during processing, a deep knowledge of the wavelet emitted by the antennas is essential. Moreover, some advanced processing techniques require specific knowledge of this signal to obtain satisfactory results. In this work, we carried out a series of tests in order to determine the source wavelet emitted by a ground-coupled antenna with a 500 MHz central frequency. PMID:22573965

  10. Range sidelobe elimination in phase-coded pulse radars

    NASA Astrophysics Data System (ADS)

    Dalle Mese, E.; Giuli, D.

    1982-08-01

    A method for reducing sidelobes in processing echoes received in phase-coded pulse radars is proposed. A recursive stable time-variant filter structure is derived which approximates an inverse code filter according to a least-squares optimality criterion. The application to the case of phase coding with binary Barker sequences is examined in detail. Performance of less complex but suboptimal filter structures are also evaluated.

  11. Simultaneous multi-channel CMW-band and MMW-band UWB monocycle pulse generation using FWM effect in a highly nonlinear photonic crystal fiber.

    PubMed

    Zhang, Fangzheng; Wu, Jian; Fu, Songnian; Xu, Kun; Li, Yan; Hong, Xiaobin; Shum, Ping; Lin, Jintong

    2010-07-19

    We propose and experimentally demonstrate a scheme to simultaneously realize multi-channel centimeter wave (CMW) band and millimeter wave (MMW) band ultra-wideband (UWB) monocycle pulse generation using four wave mixing (FWM) effect in a highly nonlinear photonic crystal fiber (HNL-PCF). Two lightwaves carrying polarity-reversed optical Gaussian pulses with appropriate time delay and another lightwave carrying a 20 GHz clock signal are launched into the HNL-PCF together. By filtering out the FWM idlers, two CMW-band UWB monocycle signals and two MMW-band UWB monocycle signals at 20 GHz are obtained simultaneously. Experimental measurements of the generated UWB monocycle pulses at individual wavelength, which comply with the FCC regulations, verify the feasibility and flexibility of proposed scheme for use in practical UWB communication systems.

  12. Mode S Data Link Phase Coding,

    DTIC Science & Technology

    1985-07-01

    AO-ft63 745 MODE S DATA LINK PHASE D DING(U) ROYAL SIGNALS AUG v RADAR ESTABLISHMENT MALVERN ( ENGLAND ) PT UPHREY ET AL. JUL 85 RSRE-NENO-3B59 DRIC-BR...be regarded as a final or official statement by the UK Civil Aviation Authority. Copyright Accession For Controller HMSO London 14TIS GRA&I - 1985...DTIC TAB I Work done under contract to the Unannounced* UK Civil Aviation Authority Justification Distribut ion/ Availability Codes Dis Special RSRE

  13. 47 CFR 15.507 - Marketing of UWB equipment.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Marketing of UWB equipment. 15.507 Section 15... Operation § 15.507 Marketing of UWB equipment. In some cases, the operation of UWB devices is limited to... state or local government. The marketing of UWB devices must be directed solely to parties eligible to...

  14. 47 CFR 15.507 - Marketing of UWB equipment.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false Marketing of UWB equipment. 15.507 Section 15... Operation § 15.507 Marketing of UWB equipment. In some cases, the operation of UWB devices is limited to... state or local government. The marketing of UWB devices must be directed solely to parties eligible to...

  15. 47 CFR 15.507 - Marketing of UWB equipment.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 1 2013-10-01 2013-10-01 false Marketing of UWB equipment. 15.507 Section 15... Operation § 15.507 Marketing of UWB equipment. In some cases, the operation of UWB devices is limited to... state or local government. The marketing of UWB devices must be directed solely to parties eligible...

  16. 47 CFR 15.507 - Marketing of UWB equipment.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 1 2014-10-01 2014-10-01 false Marketing of UWB equipment. 15.507 Section 15... Operation § 15.507 Marketing of UWB equipment. In some cases, the operation of UWB devices is limited to... state or local government. The marketing of UWB devices must be directed solely to parties eligible...

  17. 47 CFR 15.507 - Marketing of UWB equipment.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 1 2012-10-01 2012-10-01 false Marketing of UWB equipment. 15.507 Section 15... Operation § 15.507 Marketing of UWB equipment. In some cases, the operation of UWB devices is limited to... state or local government. The marketing of UWB devices must be directed solely to parties eligible...

  18. Modeling, Real-Time Estimation, and Identification of UWB Indoor Wireless Channels

    DOE PAGES

    Olama, Mohammed M.; Djouadi, Seddik M.; Li, Yanyan; ...

    2013-01-01

    Stochastic differential equations (SDEs) are used to model ultrawideband (UWB) indoor wireless channels. We show that the impulse responses for time-varying indoor wireless channels can be approximated in a mean-square sense as close as desired by impulse responses that can be realized by SDEs. The state variables represent the inphase and quadrature components of the UWB channel. The expected maximization and extended Kalman filter are employed to recursively identify and estimate the channel parameters and states, respectively, from online received signal strength measured data. Both resolvable and nonresolvable multipath received signals are considered and represented as small-scaled Nakagami fading. Themore » proposed models together with the estimation algorithm are tested using UWB indoor measurement data demonstrating the method’s viability and the results are presented.« less

  19. Modeling, Real-Time Estimation, and Identification of UWB Indoor Wireless Channels

    SciTech Connect

    Olama, Mohammed M; Djouadi, Seddik M; Li, Yanyan; Fathy, Aly

    2013-01-01

    In this paper, stochastic differential equations (SDEs) are used to model ultrawideband (UWB) indoor wireless channels. We show that the impulse responses for time-varying indoor wireless channels can be approximated in a mean square sense as close as desired by impulse responses that can be realized by SDEs. The state variables represent the inphase and quadrature components of the UWB channel. The expected maximization and extended Kalman filter are employed to recursively identify and estimate the channel parameters and states, respectively, from online received signal strength measured data. Both resolvable and non-resolvable multipath received signals are considered and represented as small-scaled Nakagami fading. The proposed models together with the estimation algorithm are tested using UWB indoor measurement data demonstrating the method s viability and the results are presented.

  20. UWB Technology and Applications on Space Exploration

    NASA Technical Reports Server (NTRS)

    Ngo, Phong; Phan, Chau; Gross, Julia; Dusl, John; Ni, Jianjun; Rafford, Melinda

    2006-01-01

    Ultra-wideband (UWB), also known as impulse or carrier-free radio technology, is one promising new technology. In February 2002, the Federal Communications Commission (FCC) approved the deployment of this technology. It is increasingly recognized that UWB technology holds great potential to provide significant benefits in many terrestrial and space applications such as precise positioning/tracking and high data rate mobile wireless communications. This talk presents an introduction to UWB technology and some applications on space exploration. UWB is characterized by several uniquely attractive features, such as low impact on other RF systems due to its extremely low power spectral densities, immunity to interference from narrow band RF systems due to its ultra-wide bandwidth, multipath immunity to fading due to ample multipath diversity, capable of precise positioning due to fine time resolution, capable of high data rate multi-channel performance. The related FCC regulations, IEEE standardization efforts and industry activities also will be addressed in this talk. For space applications, some projects currently under development at NASA Johnson Space Center will be introduced. These include the UWB integrated communication and tracking system for Lunar/Mars rover and astronauts, UWB-RFID ISS inventory tracking, and UWB-TDOA close-in high resolution tracking for potential applications on robonaut.

  1. An improved algorithm for evaluating trellis phase codes

    NASA Technical Reports Server (NTRS)

    Mulligan, M. G.; Wilson, S. G.

    1984-01-01

    A method is described for evaluating the minimum distance parameters of trellis phase codes, including CPFSK, partial response FM, and more importantly, coded CPM (continuous phase modulation) schemes. The algorithm provides dramatically faster execution times and lesser memory requirements than previous algorithms. Results of sample calculations and timing comparisons are included.

  2. An improved algorithm for evaluating trellis phase codes

    NASA Technical Reports Server (NTRS)

    Mulligan, M. G.; Wilson, S. G.

    1982-01-01

    A method is described for evaluating the minimum distance parameters of trellis phase codes, including CPFSK, partial response FM, and more importantly, coded CPM (continuous phase modulation) schemes. The algorithm provides dramatically faster execution times and lesser memory requirements than previous algorithms. Results of sample calculations and timing comparisons are included.

  3. FDTD simulation tools for UWB antenna analysis.

    SciTech Connect

    Brocato, Robert Wesley

    2004-12-01

    This paper describes the development of a set of software tools useful for analyzing ultra-wideband (UWB) antennas and structures. These tools are used to perform finite difference time domain (FDTD) simulation of a conical antenna with continuous wave (CW) and UWB pulsed excitations. The antenna is analyzed using spherical coordinate-based FDTD equations that are derived from first principles. The simulation results for CW excitation are compared to simulation and measured results from published sources; the results for UWB excitation are new.

  4. FDTD simulation tools for UWB antenna analysis.

    SciTech Connect

    Brocato, Robert Wesley

    2005-02-01

    This paper describes the development of a set of software tools useful for analyzing ultra-wideband (UWB) antennas and structures. These tools are used to perform finite difference time domain (FDTD) simulation of a conical antenna with continuous wave (CW) and UWB pulsed excitations. The antenna is analyzed using spherical coordinate-based FDTD equations that are derived from first principles. The simulation results for CW excitation are compared to simulation and measured results from published sources; the results for UWB excitation are new.

  5. Optimal Multicarrier Phase-Coded Waveform Design for Detection of Extended Targets

    SciTech Connect

    Sen, Satyabrata; Glover, Charles Wayne

    2013-01-01

    We design a parametric multicarrier phase-coded (MCPC) waveform that achieves the optimal performance in detecting an extended target in the presence of signal-dependent interference. Traditional waveform design techniques provide only the optimal energy spectral density of the transmit waveform and suffer a performance loss in the synthesis process of the time-domain signal. Therefore, we opt for directly designing an MCPC waveform in terms of its time-frequency codes to obtain the optimal detection performance. First, we describe the modeling assumptions considering an extended target buried within the signal-dependent clutter with known power spectral density, and deduce the performance characteristics of the optimal detector. Then, considering an MCPC signal transmission, we express the detection characteristics in terms of the phase-codes of the MCPC waveform and propose to optimally design the MCPC signal by maximizing the detection probability. Our numerical results demonstrate that the designed MCPC signal attains the optimal detection performance and requires a lesser computational time than the other parametric waveform design approach.

  6. All-optical UWB doublet pulses generation by using a delay interferometer

    NASA Astrophysics Data System (ADS)

    Wang, Fei; Xu, En-Ming

    2013-06-01

    We demonstrated a simple scheme to generate ultra wideband (UWB) doublet pulses by inputting a dark return-to-zero (RZ) signal into a fiber delay interferometer (FDI). An 0.625-Gbit/s dark-RZ pulse train where the pulse width is 120 ps was inputted into a FDI where the free spectral range (FSR) is 0.16 nm (˜20 GHz, according time delay is ˜50 ps) and the extinction ratio (ER) is 9 dB, and the phase difference of the two fiber arms was changed and controlled by adjusting the operation temperature of the FDI, by do so, UWB doublet pulses were directly generated at an output port of the FDI. The system parameter effects on the output UWB pulses were discussed. Moreover, we also numerically demonstrated that the UWB quadruplet pulses can be generated in the same set by optimizing system parameters. This scheme has some distinct advantages including easy integration, convenient tuning, good stability, and so on. Presented method also accords with the general features in future applied UWB-Over-Fiber communication system, such as, single optical source input, simple configuration and passive device.

  7. Statistical Modeling of Indirect Paths for UWB Sensors in an Indoor Environment

    PubMed Central

    Lee, Moona; Lee, Joon-Yong

    2016-01-01

    In this paper, we present a statistical model of an indirect path generated in an ultra-wideband (UWB) human tracking scenario. When performing moving target detection, an indirect path signal can generate ghost targets that may cause a false alarm. For this purpose, we performed radar measurements in an indoor environment and established a statistical model of an indirect path based on the measurement data. The proposed model takes the form of a modified Saleh–Valenzuela model, which is used in a UWB channel model. An application example of the proposed model for mitigating false alarms is also presented. PMID:28035978

  8. Super multi-channel recording systems with UWB wireless transmitter for BMI.

    PubMed

    Suzuki, Takafumi; Ando, Hiroshi; Yoshida, Takeshi; Sawahata, Hirohito; Kawasaki, Keisuke; Hasegawa, Isao; Matsushita, Kojiro; Hirata, Masayuki; Yoshimine, Toshiki; Takizawa, Kenichi

    2014-01-01

    In order to realize a low-invasive and high accuracy Brain-Machine Interface (BMI) system for clinical applications, a super multi-channel recording system was developed in which 4096 channels of Electrocorticogram (ECoG) signal can be amplified and transmitted to outside the body by using an Ultra Wide Band (UWB) wireless system. Also, a high density, flexible electrode array made by using a Parylene-C substrate was developed that is composed of units of 32-ch recording arrays. We have succeeded in an evaluation test of UWB wireless transmitting using a body phantom system.

  9. Pattern completion through phase coding in population neurodynamics.

    PubMed

    Gutierrez-Galvez, A; Gutierrez-Osuna, R

    2003-01-01

    This article presents an alternative phase coding mechanism for Freeman's KIII model of population neurodynamics. Motivated by experimental evidence that supports the existence of a neural code based on synchronous oscillations, we propose an analogy between synchronization in neural populations and phase locking in KIII channels. An efficient method is proposed to extract phase differences across granule channels from their state-space trajectories. First, the scale invariance of the KIII model with respect to phase information is established. The phase code is then compared against the conventional amplitude code in terms of their bit-wise and across-fiber pattern recovery capabilities using decision-theoretic principles and a Hamming-distance classifier. Graph isomorphism in the Hebbian connections is exploited to perform an exhaustive evaluation of patterns on an 8-channel KIII model. Simulation results show that phase information outperforms amplitude information in the recovery of incomplete or corrupted stimuli.

  10. Decomposition of a UWB Pulse in Structures with Facial Feedback

    NASA Astrophysics Data System (ADS)

    Gazizov, A. T.; Zabolotsky, A. M.; Gazizov, T. R.

    2017-07-01

    The urgency of protection of radio-electronic equipment from UWB pulses is indicated. The principle of modal filtration based on the application of the physical phenomenon of signal decomposition in transmission lines is shortly described. An asymmetric modal filter with facial feedback is analyzed. Its models with different parameters have been developed and manufactured. A field experiment and a computer simulation of the time response to a 1 ns pulse width have been performed. The agreement between the experimental and simulation results is demonstrated. For a modal filter with optimal parameters, the input pulse attenuation by 5 times is demonstrated in a 50-Ω channel.

  11. Spatial-phase code-division multiple-access system with multiplexed Fourier holography switching for reconfigurable optical interconnection.

    PubMed

    Takasago, K; Takekawa, M; Shirakawa, A; Kannari, F

    2000-05-10

    A new, to our knowledge, space-variant optical interconnection system based on a spatial-phase code-division multiple-access technique with multiplexed Fourier holography is described. In this technique a signal beam is spread over wide spatial frequencies by an M-sequence pseudorandom phase code. At a receiver side a selected signal beam is properly decoded, and at the same time its spatial pattern is shaped with a Fourier hologram, which is recorded by light that is encoded with the same M-sequence phase mask as the desired signal beam and by light whose spatial beam pattern is shaped to a signal routing pattern. Using the multiplexed holography, we can simultaneously route multisignal flows into individually specified receiver elements. The routing pattern can also be varied by means of switching the encoding phase code or replacing the hologram. We demonstrated a proof-of-principle experiment with a doubly multiplexed hologram that enables simultaneous routing of two signal beams. Using a numerical model, we showed that the proposed scheme can manage more than 250 routing patterns for one signal flow with one multiplexed hologram at a signal-to-noise ratio of ~5.

  12. UWB based low-cost and non-invasive practical breast cancer early detection

    NASA Astrophysics Data System (ADS)

    Vijayasarveswari, V.; Khatun, S.; Fakir, M. M.; Jusoh, M.; Ali, S.

    2017-03-01

    Breast cancer is one of the main causes of women death worldwide. Breast tumor is an early stage of cancer that locates in cells of a human breast. As there is no remedy, early detection is crucial. Towards this, Ultra-Wideband (UWB) is a prominent candidate. It is a wireless communication technology which can achieve high bandwidth with low power utilization. UWB is suitable to be used for short range communication systems including breast cancer detection since it is secure, non-invasive and human health friendly. This paper presents the low-cost and non-invasive early breast cancer detection strategy using UWB sensor (or antenna). Emphasis is given here to detect breast tumor in 2D and 3D environments. The developed system consisted of hardware and software. Hardware included UWB transceiver and a pair of home-made directional sensor/antenna. The software included feed-forward back propagation Neural Network (NN) module to detect the tumor existence, size and location along with soft interface between software and hardware. Forward scattering technique was used by placing two sensors diagonally opposite sides of a breast phantom. UWB pulses were transmitted from one side of phantom and received from other side, controlled by the software interface in PC environment. Collected received signals were then fed into the NN module for training, testing and validation. The system exhibited detection efficiency on tumor existence, location (x, y, z), and size were approximately 100%, (78.17%, 70.66%, 92.46%), 85.86% respectively. The proposed UWB based early breast cancer detection system could be more practical with low-cost, user friendly and non-harmful features. This project may help users to monitor their breast health regularly at their home.

  13. Encrypted holographic data storage based on orthogonal-phase-code multiplexing.

    PubMed

    Heanue, J F; Bashaw, M C; Hesselink, L

    1995-09-10

    We describe an encrypted holographic data-storage system that combines orthogonal-phase-code multiplexing with a random-phase key. The system offers the security advantages of random-phase coding but retains the low cross-talk performance and the minimum code storage requirements typical in an orthogonal-phase-code-multiplexing system.

  14. Vehicle positioning based on UWB technology

    NASA Astrophysics Data System (ADS)

    Hu, Siquan; Kang, Min; She, Chundong

    2017-08-01

    In recent years, with the rapid increase of the number of urban cars, the vehicle internet is becoming a trend of smart transportion. In such vehicle network, accurate location is very crucial in many new applications such as autopilot, semi-autopilot and Car-to-x communications. UWB technology has been used for indoor closed range positioning and ranging widely, while UWB outdoor positioning and ranging research is relatively less. This paper proposed UWB as the vehicle positioning technology and developed a method based on two-way-ranging (TWR) to solve the ranging problem between vehicles. At the same time, the improved TOA method was used to locate vehicles, which has higher precision compared with traditional GPS or LBS. A hardware module is introduced and the simulation results show that the modules are capable of precise positioning for vehicles in vehicle network.

  15. Studies of Scattering, Reflectivity, and Transmitivity in WBAN Channel: Feasibility of Using UWB

    PubMed Central

    Kabir, Md. Humaun; Ashrafuzzaman, Kazi; Chowdhury, M. Sanaullah; Kwak, Kyung Sup

    2010-01-01

    The Wireless Personal Area Network (WPAN) is one of the fledging paradigms that the next generation of wireless systems is sprouting towards. Among them, a more specific category is the Wireless Body Area Network (WBAN) used for health monitoring. On the other hand, Ultra-Wideband (UWB) comes with a number of desirable features at the physical layer for wireless communications. One big challenge in adoption of UWB in WBAN is the fact that signals get attenuated exponentially. Due to the intrinsic structural complexity in human body, electromagnetic waves show a profound variation during propagation through it. The reflection and transmission coefficients of human body are highly dependent upon the dielectric constants as well as upon the frequency. The difference in structural materials such as fat, muscles and blood essentially makes electromagnetic wave attenuation to be different along the way. Thus, a complete characterization of body channel is a challenging task. The connection between attenuation and frequency of the signal makes the investigation of UWB in WBAN an interesting proposition. In this paper, we study analytically the impact of body channels on electromagnetic signal propagation with reference to UWB. In the process, scattering, reflectivity and transmitivity have been addressed with analysis of approximate layer-wise modeling, and with numerical depictions. Pulses with Gaussian profile have been employed in our analysis. It shows that, under reasonable practical approximations, the human body channel can be modeled in layers so as to have the effects of total reflections or total transmissions in certain frequency bands. This could help decide such design issues as antenna characteristics of implant devices for WBAN employing UWB. PMID:22219673

  16. Performance Evaluation of MIMO-UWB Systems Using Measured Propagation Data and Proposal of Timing Control Scheme in LOS Environments

    NASA Astrophysics Data System (ADS)

    Takanashi, Masaki; Nishimura, Toshihiko; Ogawa, Yasutaka; Ohgane, Takeo

    Ultrawide-band impulse radio (UWB-IR) technology and multiple-input multiple-output (MIMO) systems have attracted interest regarding their use in next-generation high-speed radio communication. We have studied the use of MIMO ultrawide-band (MIMO-UWB) systems to enable higher-speed radio communication. We used frequency-domain equalization based on the minimum mean square error criterion (MMSE-FDE) to reduce intersymbol interference (ISI) and co-channel interference (CCI) in MIMO-UWB systems. Because UWB systems are expected to be used for short-range wireless communication, MIMO-UWB systems will usually operate in line-of-sight (LOS) environments and direct waves will be received at the receiver side. Direct waves have high power and cause high correlations between antennas in such environments. Thus, it is thought that direct waves will adversely affect the performance of spatial filtering and equalization techniques used to enhance signal detection. To examine the feasibility of MIMO-UWB systems, we conducted MIMO-UWB system propagation measurements in LOS environments. From the measurements, we found that the arrival time of direct waves from different transmitting antennas depends on the MIMO configuration. Because we can obtain high power from the direct waves, direct wave reception is critical for maximizing transmission performance. In this paper, we present our measurement results, and propose a way to improve performance using a method of transmit (Tx) and receive (Rx) timing control. We evaluate the bit error rate (BER) performance for this form of timing control using measured channel data.

  17. A UWB/Improved PDR Integration Algorithm Applied to Dynamic Indoor Positioning for Pedestrians.

    PubMed

    Chen, Pengzhan; Kuang, Ye; Chen, Xiaoyue

    2017-09-08

    Inertial sensors are widely used in various applications, such as human motion monitoring and pedestrian positioning. However, inertial sensors cannot accurately define the process of human movement, a limitation that causes data drift in the process of human body positioning, thus seriously affecting positioning accuracy and stability. The traditional pedestrian dead-reckoning algorithm, which is based on a single inertial measurement unit, can suppress the data drift, but fails to accurately calculate the number of walking steps and heading value, thus it cannot meet the application requirements. This study proposes an indoor dynamic positioning method with an error self-correcting function based on the symmetrical characteristics of human motion to obtain the definition basis of human motion process quickly and to solve the abovementioned problems. On the basis of this proposed method, an ultra-wide band (UWB) method is introduced. An unscented Kalman filter is applied to fuse inertial sensors and UWB data, inertial positioning is applied to compensation for the defects of susceptibility to UWB signal obstacles, and UWB positioning is used to overcome the error accumulation of inertial positioning. The above method can improve both the positioning accuracy and the response of the positioning results. Finally, this study designs an indoor positioning test system to test the static and dynamic performances of the proposed indoor positioning method. Results show that the positioning system both has high accuracy and good real-time performance.

  18. The laser linewidth effect on the image quality of phase coded synthetic aperture ladar

    NASA Astrophysics Data System (ADS)

    Cai, Guangyu; Hou, Peipei; Ma, Xiaoping; Sun, Jianfeng; Zhang, Ning; Li, Guangyuan; Zhang, Guo; Liu, Liren

    2015-12-01

    The phase coded (PC) waveform in synthetic aperture ladar (SAL) outperforms linear frequency modulated (LFM) signal in lower side lobe, shorter pulse duration and making the rigid control of the chirp starting point in every pulse unnecessary. Inherited from radar PC waveform and strip map SAL, the backscattered signal of a point target in PC SAL was listed and the two dimensional match filtering algorithm was introduced to focus a point image. As an inherent property of laser, linewidth is always detrimental to coherent ladar imaging. With the widely adopted laser linewidth model, the effect of laser linewidth on SAL image quality was theoretically analyzed and examined via Monte Carlo simulation. The research gives us a clear view of how to select linewidth parameters in the future PC SAL systems.

  19. Short pulse acquisition by low sampling rate with phase-coded sequence in lidar system

    NASA Astrophysics Data System (ADS)

    Wu, Long; Xu, Jiajia; Lv, Wentao; Yang, Xiaocheng

    2016-11-01

    The requirement of high range resolution results in impractical collection of every returned laser pulse due to the limited response speed of imaging detectors. This paper proposes a phase coded sequence acquisition method for signal preprocessing. The system employs an m-sequence with N bits for demonstration with the detector controlled to accumulate N+1 bits of the echo signals to deduce one single returned laser pulse. An indoor experiment achieved 2 μs resolution with the sampling period of 28 μs by employing a 15-bit m-sequence. This method shows the potential to improve the detection capabilities of narrow laser pulses with the detectors at a low frame rate, especially for the imaging lidar systems. Meanwhile, the lidar system is able to improve the range resolution with available detectors of restricted performance.

  20. Third order harmonic imaging for biological tissues using three phase-coded pulses.

    PubMed

    Ma, Qingyu; Gong, Xiufen; Zhang, Dong

    2006-12-22

    Compared to the fundamental and the second harmonic imaging, the third harmonic imaging shows significant improvements in image quality due to the better resolution, but it is degraded by the lower sound pressure and signal-to-noise ratio (SNR). In this study, a phase-coded pulse technique is proposed to selectively enhance the sound pressure of the third harmonic by 9.5 dB whereas the fundamental and the second harmonic components are efficiently suppressed and SNR is also increased by 4.7 dB. Based on the solution of the KZK nonlinear equation, the axial and lateral beam profiles of harmonics radiated from a planar piston transducer were theoretically simulated and experimentally examined. Finally, the third harmonic images using this technique were performed for several biological tissues and compared with the images obtained by the fundamental and the second harmonic imaging. Results demonstrate that the phase-coded pulse technique yields a dramatically cleaner and sharper contrast image.

  1. Non-invasive UWB sensing of astronauts' breathing activity.

    PubMed

    Baldi, Marco; Cerri, Graziano; Chiaraluce, Franco; Eusebi, Lorenzo; Russo, Paola

    2014-12-30

    The use of a UWB system for sensing breathing activity of astronauts must account for many critical issues specific to the space environment. The aim of this paper is twofold. The first concerns the definition of design constraints about the pulse amplitude and waveform to transmit, as well as the immunity requirements of the receiver. The second issue concerns the assessment of the procedures and the characteristics of the algorithms to use for signal processing to retrieve the breathing frequency and respiration waveform. The algorithm has to work correctly in the presence of surrounding electromagnetic noise due to other sources in the environment. The highly reflecting walls increase the difficulty of the problem and the hostile scenario has to be accurately characterized. Examples of signal processing techniques able to recover breathing frequency in significant and realistic situations are shown and discussed.

  2. Non-Invasive UWB Sensing of Astronauts' Breathing Activity

    PubMed Central

    Baldi, Marco; Cerri, Graziano; Chiaraluce, Franco; Eusebi, Lorenzo; Russo, Paola

    2015-01-01

    The use of a UWB system for sensing breathing activity of astronauts must account for many critical issues specific to the space environment. The aim of this paper is twofold. The first concerns the definition of design constraints about the pulse amplitude and waveform to transmit, as well as the immunity requirements of the receiver. The second issue concerns the assessment of the procedures and the characteristics of the algorithms to use for signal processing to retrieve the breathing frequency and respiration waveform. The algorithm has to work correctly in the presence of surrounding electromagnetic noise due to other sources in the environment. The highly reflecting walls increase the difficulty of the problem and the hostile scenario has to be accurately characterized. Examples of signal processing techniques able to recover breathing frequency in significant and realistic situations are shown and discussed. PMID:25558995

  3. A novel through-wall respiration detection algorithm using UWB radar.

    PubMed

    Li, Xin; Qiao, Dengyu; Li, Ye; Dai, Huhe

    2013-01-01

    Through-wall respiration detection using Ultra-wideband (UWB) impulse radar can be applied to the post-disaster rescue, e.g., searching living persons trapped in ruined buildings after an earthquake. Since strong interference signals always exist in the real-life scenarios, such as static clutter, noise, etc., while the respiratory signal is very weak, the signal to noise and clutter ratio (SNCR) is quite low. Therefore, through-wall respiration detection using UWB impulse radar under low SNCR is a challenging work in the research field of searching survivors after disaster. In this paper, an improved UWB respiratory signal model is built up based on an even power of cosine function for the first time. This model is used to reveal the harmonic structure of respiratory signal, based on which a novel high-performance respiration detection algorithm is proposed. This novel algorithm is assessed by experimental verification and simulation and shows about a 1.5dB improvement of SNR and SNCR.

  4. Noise Analysis of Spatial Phase coding in analog Acoustooptic Processors

    NASA Technical Reports Server (NTRS)

    Gary, Charles K.; Lum, Henry, Jr. (Technical Monitor)

    1994-01-01

    Optical beams can carry information in their amplitude and phase; however, optical analog numerical calculators such as an optical matrix processor use incoherent light to achieve linear operation. Thus, the phase information is lost and only the magnitude can be used. This limits such processors to the representation of positive real numbers. Many systems have been devised to overcome this deficit through the use of digital number representations, but they all operate at a greatly reduced efficiency in contrast to analog systems. The most widely accepted method to achieve sign coding in analog optical systems has been the use of an offset for the zero level. Unfortunately, this results in increased noise sensitivity for small numbers. In this paper, we examine the use of spatially coherent sign coding in acoustooptical processors, a method first developed for digital calculations by D. V. Tigin. This coding technique uses spatial coherence for the representation of signed numbers, while temporal incoherence allows for linear analog processing of the optical information. We show how spatial phase coding reduces noise sensitivity for signed analog calculations.

  5. FPGA based digital phase-coding quantum key distribution system

    NASA Astrophysics Data System (ADS)

    Lu, XiaoMing; Zhang, LiJun; Wang, YongGang; Chen, Wei; Huang, DaJun; Li, Deng; Wang, Shuang; He, DeYong; Yin, ZhenQiang; Zhou, Yu; Hui, Cong; Han, ZhengFu

    2015-12-01

    Quantum key distribution (QKD) is a technology with the potential capability to achieve information-theoretic security. Phasecoding is an important approach to develop practical QKD systems in fiber channel. In order to improve the phase-coding modulation rate, we proposed a new digital-modulation method in this paper and constructed a compact and robust prototype of QKD system using currently available components in our lab to demonstrate the effectiveness of the method. The system was deployed in laboratory environment over a 50 km fiber and continuously operated during 87 h without manual interaction. The quantum bit error rate (QBER) of the system was stable with an average value of 3.22% and the secure key generation rate is 8.91 kbps. Although the modulation rate of the photon in the demo system was only 200 MHz, which was limited by the Faraday-Michelson interferometer (FMI) structure, the proposed method and the field programmable gate array (FPGA) based electronics scheme have a great potential for high speed QKD systems with Giga-bits/second modulation rate.

  6. Transmission over UWB channels with OFDM system using LDPC coding

    NASA Astrophysics Data System (ADS)

    Dziwoki, Grzegorz; Kucharczyk, Marcin; Sulek, Wojciech

    2009-06-01

    Hostile wireless environment requires use of sophisticated signal processing methods. The paper concerns on Ultra Wideband (UWB) transmission over Personal Area Networks (PAN) including MB-OFDM specification of physical layer. In presented work the transmission system with OFDM modulation was connected with LDPC encoder/decoder. Additionally the frame and bit error rate (FER and BER) of the system was decreased using results from the LDPC decoder in a kind of turbo equalization algorithm for better channel estimation. Computational block using evolutionary strategy, from genetic algorithms family, was also used in presented system. It was placed after SPA (Sum-Product Algorithm) decoder and is conditionally turned on in the decoding process. The result is increased effectiveness of the whole system, especially lower FER. The system was tested with two types of LDPC codes, depending on type of parity check matrices: randomly generated and constructed deterministically, optimized for practical decoder architecture implemented in the FPGA device.

  7. UWB Impulse Radar Characterization and Processing Techniques

    DTIC Science & Technology

    2004-12-01

    S/B s’améliore de façon à peu près linéaire . L’intégration d’environ 80 impulsions donne lieu à un rapport S/B maximal d’environ 35 dB, avec une...défense Canada (RDDC) a un programme de recherche active sur bien des aspects des systèmes radar à bande ultra-large (UWB), y compris la simulation

  8. A software reconfigurable optical multiband UWB system utilizing a bit-loading combined with adaptive LDPC code rate scheme

    NASA Astrophysics Data System (ADS)

    He, Jing; Dai, Min; Chen, Qinghui; Deng, Rui; Xiang, Changqing; Chen, Lin

    2017-07-01

    In this paper, an effective bit-loading combined with adaptive LDPC code rate algorithm is proposed and investigated in software reconfigurable multiband UWB over fiber system. To compensate the power fading and chromatic dispersion for the high frequency of multiband OFDM UWB signal transmission over standard single mode fiber (SSMF), a Mach-Zehnder modulator (MZM) with negative chirp parameter is utilized. In addition, the negative power penalty of -1 dB for 128 QAM multiband OFDM UWB signal are measured at the hard-decision forward error correction (HD-FEC) limitation of 3.8 × 10-3 after 50 km SSMF transmission. The experimental results show that, compared to the fixed coding scheme with the code rate of 75%, the signal-to-noise (SNR) is improved by 2.79 dB for 128 QAM multiband OFDM UWB system after 100 km SSMF transmission using ALCR algorithm. Moreover, by employing bit-loading combined with ALCR algorithm, the bit error rate (BER) performance of system can be further promoted effectively. The simulation results present that, at the HD-FEC limitation, the value of Q factor is improved by 3.93 dB at the SNR of 19.5 dB over 100 km SSMF transmission, compared to the fixed modulation with uncoded scheme at the same spectrum efficiency (SE).

  9. Location detection and tracking of moving targets by a 2D IR-UWB radar system.

    PubMed

    Nguyen, Van-Han; Pyun, Jae-Young

    2015-03-19

    In indoor environments, the Global Positioning System (GPS) and long-range tracking radar systems are not optimal, because of signal propagation limitations in the indoor environment. In recent years, the use of ultra-wide band (UWB) technology has become a possible solution for object detection, localization and tracking in indoor environments, because of its high range resolution, compact size and low cost. This paper presents improved target detection and tracking techniques for moving objects with impulse-radio UWB (IR-UWB) radar in a short-range indoor area. This is achieved through signal-processing steps, such as clutter reduction, target detection, target localization and tracking. In this paper, we introduce a new combination consisting of our proposed signal-processing procedures. In the clutter-reduction step, a filtering method that uses a Kalman filter (KF) is proposed. Then, in the target detection step, a modification of the conventional CLEAN algorithm which is used to estimate the impulse response from observation region is applied for the advanced elimination of false alarms. Then, the output is fed into the target localization and tracking step, in which the target location and trajectory are determined and tracked by using unscented KF in two-dimensional coordinates. In each step, the proposed methods are compared to conventional methods to demonstrate the differences in performance. The experiments are carried out using actual IR-UWB radar under different scenarios. The results verify that the proposed methods can improve the probability and efficiency of target detection and tracking.

  10. Location Detection and Tracking of Moving Targets by a 2D IR-UWB Radar System

    PubMed Central

    Nguyen, Van-Han; Pyun, Jae-Young

    2015-01-01

    In indoor environments, the Global Positioning System (GPS) and long-range tracking radar systems are not optimal, because of signal propagation limitations in the indoor environment. In recent years, the use of ultra-wide band (UWB) technology has become a possible solution for object detection, localization and tracking in indoor environments, because of its high range resolution, compact size and low cost. This paper presents improved target detection and tracking techniques for moving objects with impulse-radio UWB (IR-UWB) radar in a short-range indoor area. This is achieved through signal-processing steps, such as clutter reduction, target detection, target localization and tracking. In this paper, we introduce a new combination consisting of our proposed signal-processing procedures. In the clutter-reduction step, a filtering method that uses a Kalman filter (KF) is proposed. Then, in the target detection step, a modification of the conventional CLEAN algorithm which is used to estimate the impulse response from observation region is applied for the advanced elimination of false alarms. Then, the output is fed into the target localization and tracking step, in which the target location and trajectory are determined and tracked by using unscented KF in two-dimensional coordinates. In each step, the proposed methods are compared to conventional methods to demonstrate the differences in performance. The experiments are carried out using actual IR-UWB radar under different scenarios. The results verify that the proposed methods can improve the probability and efficiency of target detection and tracking. PMID:25808773

  11. UWB Tracking System Design with TDOA Algorithm

    NASA Technical Reports Server (NTRS)

    Ni, Jianjun; Arndt, Dickey; Ngo, Phong; Phan, Chau; Gross, Julia; Dusl, John; Schwing, Alan

    2006-01-01

    This presentation discusses an ultra-wideband (UWB) tracking system design effort using a tracking algorithm TDOA (Time Difference of Arrival). UWB technology is exploited to implement the tracking system due to its properties, such as high data rate, fine time resolution, and low power spectral density. A system design using commercially available UWB products is proposed. A two-stage weighted least square method is chosen to solve the TDOA non-linear equations. Matlab simulations in both two-dimensional space and three-dimensional space show that the tracking algorithm can achieve fine tracking resolution with low noise TDOA data. The error analysis reveals various ways to improve the tracking resolution. Lab experiments demonstrate the UWBTDOA tracking capability with fine resolution. This research effort is motivated by a prototype development project Mini-AERCam (Autonomous Extra-vehicular Robotic Camera), a free-flying video camera system under development at NASA Johnson Space Center for aid in surveillance around the International Space Station (ISS).

  12. Application of UWB and MIMO Wireless Technologies to Tactical Networks in Austere Environments

    DTIC Science & Technology

    2010-09-01

    26 a. DRACO System .......................................................................26 b. Aircraft Wireless...Figure 12. Various UWB modulation techniques [from: Chung & et al., 2009] ..............25 Figure 13. DRACO UWB Communication Node [from: Fontana & et...Some of these systems are: DRACO , AWICS, Hydra UWB, PUMA system, and Trident’s UWB unattended ground sensors (UGS) and mesh network system. Even

  13. Associative recall in a volume holographic storage system based on phase-code multiplexing

    NASA Astrophysics Data System (ADS)

    Berger, G.; Denz, C.; Orlov, S. S.; Phillips, B.; Hesselink, L.

    2001-12-01

    We present two different techniques on how to realize a content-addressed holographic memory when using phase-code multiplexing, relying on simple intensity measurements rather than phase distributions. Theoretical and experimental results of associative recall in a phase-coded system designed for digital data storage will be presented and compared to the corresponding method when using angular multiplexing.

  14. A DS-UWB Cognitive Radio System Based on Bridge Function Smart Codes

    NASA Astrophysics Data System (ADS)

    Xu, Yafei; Hong, Sheng; Zhao, Guodong; Zhang, Fengyuan; di, Jinshan; Zhang, Qishan

    This paper proposes a direct-sequence UWB Gaussian pulse of cognitive radio systems based on bridge function smart sequence matrix and the Gaussian pulse. As the system uses the spreading sequence code, that is the bridge function smart code sequence, the zero correlation zones (ZCZs) which the bridge function sequences' auto-correlation functions had, could reduce multipath fading of the pulse interference. The Modulated channel signal was sent into the IEEE 802.15.3a UWB channel. We analysis the ZCZs's inhibition to the interference multipath interference (MPI), as one of the main system sources interferences. The simulation in SIMULINK/MATLAB is described in detail. The result shows the system has better performance by comparison with that employing Walsh sequence square matrix, and it was verified by the formula in principle.

  15. Multichannel neural recording with a 128 Mbps UWB wireless transmitter for implantable brain-machine interfaces.

    PubMed

    Ando, H; Takizawa, K; Yoshida, T; Matsushita, K; Hirata, M; Suzuki, T

    2015-01-01

    To realize a low-invasive and high accuracy BMI (Brain-machine interface) system, we have already developed a fully-implantable wireless BMI system which consists of ECoG neural electrode arrays, neural recording ASICs, a Wi-Fi based wireless data transmitter and a wireless power receiver with a rechargeable battery. For accurate estimation of movement intentions, it is important for a BMI system to have a large number of recording channels. In this paper, we report a new multi-channel BMI system which is able to record up to 4096-ch ECoG data by multiple connections of 64-ch ASICs and time division multiplexing of recorded data. This system has an ultra-wide-band (UWB) wireless unit for transmitting the recorded neural signals to outside the body. By preliminary experiments with a human body equivalent liquid phantom, we confirmed 4096-ch UWB wireless data transmission at 128 Mbps mode below 20 mm distance.

  16. Ultra-wideband signal generator based on cross gain modulation effect in a distributed feedback laser

    NASA Astrophysics Data System (ADS)

    Chen, Dalei; Wang, Rong; Xiang, Peng; Pu, Tao; Fang, Tao; Li, Yuandong; Su, Yang; Zheng, Jiling; Huang, Long; Zhu, Huatao; Huang, Jie

    2016-10-01

    In this paper, a novel scheme to generate ultra-wideband (UWB) signals based on cross-gain modulation (XGM) effect in a DFB laser is proposed and experimentally demonstrated, and the modulation and transmission of the UWB signals are also experimentally investigated. In the proposed system, a gain-switched laser (GSL) is used as master laser (ML) and the optical pulses from the ML are optically injected into a DFB laser, which is used as slave laser (SL). By proper system configuration, UWB monocycle, doublet or triplet UWB signals can be generated after the balanced photodiode (BPD) detection. Besides, other modulation formats can also be realized, such as on-off keying (OOK) and pulse amplitude modulation (PAM) by properly modulating the ML optical pulses. Finally, fiber transmission of the modulated UWB signals is experimentally investigated, and it is shown that the UWB signals can be well maintained after 40 km optical fiber transmission.

  17. Impact evaluation of conducted UWB transients on loads in power-line networks

    NASA Astrophysics Data System (ADS)

    Li, Bing; Månsson, Daniel

    2017-09-01

    Nowadays, faced with the ever-increasing dependence on diverse electronic devices and systems, the proliferation of potential electromagnetic interference (EMI) becomes a critical threat for reliable operation. A typical issue is the electronics working reliably in power-line networks when exposed to electromagnetic environment. In this paper, we consider a conducted ultra-wideband (UWB) disturbance, as an example of intentional electromagnetic interference (IEMI) source, and perform the impact evaluation at the loads in a network. With the aid of fast Fourier transform (FFT), the UWB transient is characterized in the frequency domain. Based on a modified Baum-Liu-Tesche (BLT) method, the EMI received at the loads, with complex impedance, is computed. Through inverse FFT (IFFT), we obtain time-domain responses of the loads. To evaluate the impact on loads, we employ five common, but important quantifiers, i.e., time-domain peak, total signal energy, peak signal power, peak time rate of change and peak time integral of the pulse. Moreover, to perform a comprehensive analysis, we also investigate the effects of the attributes (capacitive, resistive, or inductive) of other loads connected to the network, the rise time and pulse width of the UWB transient, and the lengths of power lines. It is seen that, for the loads distributed in a network, the impact evaluation of IEMI should be based on the characteristics of the IEMI source, and the network features, such as load impedances, layout, and characteristics of cables.

  18. Dual-frequency tissue harmonic suppression using phase-coded pulse sequence: proof of concept using a phantom.

    PubMed

    Shen, Che-Chou; Wang, Hui-Ting

    2013-03-01

    The presence of tissue harmonic generation during acoustic propagation is one major limitation in nonlinear detection of microbubble contrast agents. However, conventional solutions for tissue harmonic suppression are not applicable in dual-frequency (DF) harmonic imaging. In DF harmonic imaging, the second harmonic signal at second harmonic (2f(0)) frequency and the inter-modulation harmonic signal at fundamental (f(0)) frequency are simultaneously generated for imaging and both need to be suppressed to improve contrast-to-tissue ratio (CTR). In this study, a novel phase-coded pulse sequence is developed to accomplish DF tissue harmonic suppression. Phase-coded pulse sequence utilizes multiple firings with equidistant transmit phase for harmonic cancellation in the sum of respective echoes. For the f(0) transmit component, the transmit phase comes from the equidistant set of {-2π/3, 0, 2π/3} to suppress the second harmonic signal at 2f(0) frequency. Moreover, in order to provide the inter-modulation harmonic suppression at f(0) frequency, the 2f(0) transmit phase has to be particularly manipulated for the corresponding f(0) transmit phase. The proposed three-pulse sequence can remove not only the second-order harmonic signal but also other higher-order counterparts at both f(0) and 2f(0) frequencies. Measurements were performed at f(0) equal to 2.25 MHz and using hydrophone in water and contrast agents in tissue phantom. Experimental results indicate that the sequence reduces the tissue harmonic magnitude by about 20 dB along the entire axial depths and the corresponding CTR improves at both frequencies. In DF harmonic imaging, the proposed phase-coded sequence can effectively remove the tissue harmonic background at both f(0) and 2f(0) frequencies for improvement of contrast detection. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. UWB Tracking System Design for Free-Flyers

    NASA Technical Reports Server (NTRS)

    Ni, Jianjun; Arndt, Dickey; Phan, Chan; Ngo, Phong; Gross, Julia; Dusl, John

    2004-01-01

    This paper discusses an ultra-wideband (UWB) tracking system design effort for Mini-AERCam (Autonomous Extra-vehicular Robotic Camera), a free-flying video camera system under development at NASA Johnson Space Center for aid in surveillance around the International Space Station (ISS). UWB technology is exploited to implement the tracking system due to its properties, such as high data rate, fine time resolution, and low power spectral density. A system design using commercially available UWB products is proposed. A tracking algorithm TDOA (Time Difference of Arrival) that operates cooperatively with the UWB system is developed in this research effort. Matlab simulations show that the tracking algorithm can achieve fine tracking resolution with low noise TDOA data. Lab experiments demonstrate the UWB tracking capability with fine resolution.

  20. Phase coded, micro-power impulse radar motion sensor

    DOEpatents

    McEwan, Thomas E.

    1996-01-01

    A motion sensing, micro-power impulse radar MIR impresses on the transmitted signal, or the received pulse timing signal, one or more frequencies lower than the pulse repetition frequency, that become intermediate frequencies in a "IF homodyne" receiver. Thus, many advantages of classical RF receivers can be thereby be realized with ultra-wide band radar. The sensor includes a transmitter which transmits a sequence of electromagnetic pulses in response to a transmit timing signal at a nominal pulse repetition frequency. A receiver samples echoes of the sequence of electromagnetic pulses from objects within the field with controlled timing, in response to a receive timing signal, and generates a sample signal in response to the samples. A timing circuit supplies the transmit timing signal to the transmitter and supplies the receive timing signal to the receiver. The relative timing of the transmit timing signal and the receive timing signal is modulated between a first relative delay and a second relative delay at an intermediate frequency, causing the receiver to sample the echoes such that the time between transmissions of pulses in the sequence and samples by the receiver is modulated at the intermediate frequency. Modulation may be executed by modulating the pulse repetition frequency which drives the transmitter, by modulating the delay circuitry which controls the relative timing of the sample strobe, or by modulating amplitude of the transmitted pulses. The electromagnetic pulses will have a nominal center frequency related to pulse width, and the first relative delay and the second relative delay between which the timing signals are modulated, differ by less than the nominal pulse width, and preferably by about one-quarter wavelength at the nominal center frequency of the transmitted pulses.

  1. Phase coded, micro-power impulse radar motion sensor

    DOEpatents

    McEwan, T.E.

    1996-05-21

    A motion sensing, micro-power impulse radar MIR impresses on the transmitted signal, or the received pulse timing signal, one or more frequencies lower than the pulse repetition frequency, that become intermediate frequencies in a ``IF homodyne`` receiver. Thus, many advantages of classical RF receivers can be thereby be realized with ultra-wide band radar. The sensor includes a transmitter which transmits a sequence of electromagnetic pulses in response to a transmit timing signal at a nominal pulse repetition frequency. A receiver samples echoes of the sequence of electromagnetic pulses from objects within the field with controlled timing, in response to a receive timing signal, and generates a sample signal in response to the samples. A timing circuit supplies the transmit timing signal to the transmitter and supplies the receive timing signal to the receiver. The relative timing of the transmit timing signal and the receive timing signal is modulated between a first relative delay and a second relative delay at an intermediate frequency, causing the receiver to sample the echoes such that the time between transmissions of pulses in the sequence and samples by the receiver is modulated at the intermediate frequency. Modulation may be executed by modulating the pulse repetition frequency which drives the transmitter, by modulating the delay circuitry which controls the relative timing of the sample strobe, or by modulating amplitude of the transmitted pulses. The electromagnetic pulses will have a nominal center frequency related to pulse width, and the first relative delay and the second relative delay between which the timing signals are modulated, differ by less than the nominal pulse width, and preferably by about one-quarter wavelength at the nominal center frequency of the transmitted pulses. 5 figs.

  2. Two Novel Space-Time Coding Techniques Designed for UWB MISO Systems Based on Wavelet Transform.

    PubMed

    Zaki, Amira Ibrahim; Badran, Ehab F; El-Khamy, Said E

    2016-01-01

    In this paper two novel space-time coding multi-input single-output (STC MISO) schemes, designed especially for Ultra-Wideband (UWB) systems, are introduced. The proposed schemes are referred to as wavelet space-time coding (WSTC) schemes. The WSTC schemes are based on two types of multiplexing, spatial and wavelet domain multiplexing. In WSTC schemes, four symbols are transmitted on the same UWB transmission pulse with the same bandwidth, symbol duration, and number of transmitting antennas of the conventional STC MISO scheme. The used mother wavelet (MW) is selected to be highly correlated with transmitted pulse shape and such that the multiplexed signal has almost the same spectral characteristics as those of the original UWB pulse. The two WSTC techniques increase the data rate to four times that of the conventional STC. The first WSTC scheme increases the data rate with a simple combination process. The second scheme achieves the increase in the data rate with a less complex receiver and better performance than the first scheme due to the spatial diversity introduced by the structure of its transmitter and receiver. The two schemes use Rake receivers to collect the energy in the dense multipath channel components. The simulation results show that the proposed WSTC schemes have better performance than the conventional scheme in addition to increasing the data rate to four times that of the conventional STC scheme.

  3. Two Novel Space-Time Coding Techniques Designed for UWB MISO Systems Based on Wavelet Transform

    PubMed Central

    Zaki, Amira Ibrahim; El-Khamy, Said E.

    2016-01-01

    In this paper two novel space-time coding multi-input single-output (STC MISO) schemes, designed especially for Ultra-Wideband (UWB) systems, are introduced. The proposed schemes are referred to as wavelet space-time coding (WSTC) schemes. The WSTC schemes are based on two types of multiplexing, spatial and wavelet domain multiplexing. In WSTC schemes, four symbols are transmitted on the same UWB transmission pulse with the same bandwidth, symbol duration, and number of transmitting antennas of the conventional STC MISO scheme. The used mother wavelet (MW) is selected to be highly correlated with transmitted pulse shape and such that the multiplexed signal has almost the same spectral characteristics as those of the original UWB pulse. The two WSTC techniques increase the data rate to four times that of the conventional STC. The first WSTC scheme increases the data rate with a simple combination process. The second scheme achieves the increase in the data rate with a less complex receiver and better performance than the first scheme due to the spatial diversity introduced by the structure of its transmitter and receiver. The two schemes use Rake receivers to collect the energy in the dense multipath channel components. The simulation results show that the proposed WSTC schemes have better performance than the conventional scheme in addition to increasing the data rate to four times that of the conventional STC scheme. PMID:27959939

  4. Detection of motion and posture change using an IR-UWB radar.

    PubMed

    Van Nguyen; Javaid, Abdul Q; Weitnauer, Mary A

    2016-08-01

    Impulse radio ultra-wide band (IR-UWB) radar has recently emerged as a promising candidate for non-contact monitoring of respiration and heart rate. Different studies have reported various radar based algorithms for estimation of these physiological parameters. The radar can be placed under a subject's mattress as he lays stationary on his back or it can be attached to the ceiling directly above the subject's bed. However, advertent or inadvertent movement on part of the subject and different postures can affect the radar returned signal and also the accuracy of the estimated parameters from it. The detection and analysis of these postural changes can not only lead to improvement in estimation algorithms but also towards prevention of bed sores and ulcers in patients who require periodic posture changes. In this paper, we present an algorithm that detects and quantifies different types of motion events using an under-the-mattress IR-UWB radar. The algorithm also indicates a change in posture after a macro-movement event. Based on the findings of this paper, we anticipate that IR-UWB radar can be used for extracting posture related information in non-clinical enviroments for patients who are bed-ridden.

  5. Band-notched reconfigurable CPW-fed UWB antenna

    NASA Astrophysics Data System (ADS)

    Majid, H. A.; Rahim, M. K. A.; Hamid, M. R.; Murad, N. A.; Samsuri, N. A.; Yusof, M. F. M.; Kamarudin, M. R.

    2016-04-01

    A reconfigurable band-notched CPW-fed UWB antenna using electromagnetic bandgap (EBG) structure is proposed. Two structures are positioned adjacent to the transmission line of the UWB antenna. The band-notched characteristic can be disabled by switching the state of switch place at the strip line. The EBG structure produces reconfigurable band notched at 4.0 GHz, which covers C-band satellite communication (3.625-4.2 GHz) systems. The proposed antenna is suitable for UWB systems, which requires reconfigurable band reject function.

  6. Body Area Networks performance analysis using UWB.

    PubMed

    Fatehy, Mohammed; Kohno, Ryuji

    2013-01-01

    The successful realization of a Wireless Body Area Network (WBAN) using Ultra Wideband (UWB) technology supports different medical and consumer electronics (CE) applications but stand in a need for an innovative solution to meet the different requirements of these applications. Previously, we proposed to use adaptive processing gain (PG) to fulfill the different QoS requirements of these WBAN applications. In this paper, interference occurred between two different BANs in a UWB-based system has been analyzed in terms of acceptable ratio of overlapping between these BANs' PG providing the required QoS for each BAN. The first BAN employed for a healthcare device (e.g. EEG, ECG, etc.) with a relatively longer spreading sequence is used and the second customized for entertainment application (e.g. wireless headset, wireless game pad, etc.) where a shorter spreading code is assigned. Considering bandwidth utilization and difference in the employed spreading sequence, the acceptable ratio of overlapping between these BANs should fall between 0.05 and 0.5 in order to optimize the used spreading sequence and in the meantime satisfying the required QoS for these applications.

  7. Phase-coded multi-pulse technique for ultrasonic high-order harmonic imaging of biological tissues in vitro.

    PubMed

    Ma, Qingyu; Zhang, Dong; Gong, Xiufen; Ma, Yong

    2007-04-07

    Second or higher order harmonic imaging shows significant improvement in image clarity but is degraded by low signal-noise ratio (SNR) compared with fundamental imaging. This paper presents a phase-coded multi-pulse technique to provide the enhancement of SNR for the desired high-order harmonic ultrasonic imaging. In this technique, with N phase-coded pulses excitation, the received Nth harmonic signal is enhanced by 20 log(10)N dB compared with that in the single-pulse mode, whereas the fundamental and other order harmonic components are efficiently suppressed to reduce image confusion. The principle of this technique is theoretically discussed based on the theory of the finite amplitude sound waves, and examined by measurements of the axial and lateral beam profiles as well as the phase shift of the harmonics. In the experimental imaging for two biological tissue specimens, a plane piston source at 2 MHz is used to transmit a sequence of multiple pulses with equidistant phase shift. The second to fifth harmonic images are obtained using this technique with N = 2 to 5, and compared with the images obtained at the fundamental frequency. Results demonstrate that this technique of relying on higher order harmonics seems to provide a better resolution and contrast of ultrasonic images.

  8. A Novel Design of Frequency Reconfigurable Antenna for UWB Application

    NASA Astrophysics Data System (ADS)

    Yang, Xiaolin; Yu, Ziliang; Wu, Zheng; Shen, Huajiao

    2016-09-01

    In this paper, we present a novel frequency reconfigurable antenna which could be easily operate in a single notched-band (WiMAX (3.3-3.6 GHz)) UWB frequency band, another single notched-band (WLAN (5-6 GHz)) UWB frequency band and the dual band-notched UWB frequency band (the stopband covers the WiMAX (3.3-3.6 GHz) and WLAN (5-6 GHz)). The reconfigurability is achieved by changing the states of PIN diodes. The simulated results are in agreement well with the measured results. And the measured patterns are slightly changed with antenna reconfiguration. The proposed antenna is a good candidate for various UWB applications.

  9. Detection of Multiple Stationary Humans Using UWB MIMO Radar

    PubMed Central

    Liang, Fulai; Qi, Fugui; An, Qiang; Lv, Hao; Chen, Fuming; Li, Zhao; Wang, Jianqi

    2016-01-01

    Remarkable progress has been achieved in the detection of single stationary human. However, restricted by the mutual interference of multiple humans (e.g., strong sidelobes of the torsos and the shadow effect), detection and localization of the multiple stationary humans remains a huge challenge. In this paper, ultra-wideband (UWB) multiple-input and multiple-output (MIMO) radar is exploited to improve the detection performance of multiple stationary humans for its multiple sight angles and high-resolution two-dimensional imaging capacity. A signal model of the vital sign considering both bi-static angles and attitude angle of the human body is firstly developed, and then a novel detection method is proposed to detect and localize multiple stationary humans. In this method, preprocessing is firstly implemented to improve the signal-to-noise ratio (SNR) of the vital signs, and then a vital-sign-enhanced imaging algorithm is presented to suppress the environmental clutters and mutual affection of multiple humans. Finally, an automatic detection algorithm including constant false alarm rate (CFAR), morphological filtering and clustering is implemented to improve the detection performance of weak human targets affected by heavy clutters and shadow effect. The simulation and experimental results show that the proposed method can get a high-quality image of multiple humans and we can use it to discriminate and localize multiple adjacent human targets behind brick walls. PMID:27854356

  10. 47 CFR 15.519 - Technical requirements for hand held UWB systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... information to an associated receiver. The UWB intentional radiator shall cease transmission within 10 seconds... received. An acknowledgment of reception must continue to be received by the UWB intentional radiator...

  11. 47 CFR 15.519 - Technical requirements for hand held UWB systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... information to an associated receiver. The UWB intentional radiator shall cease transmission within 10 seconds... received. An acknowledgment of reception must continue to be received by the UWB intentional radiator...

  12. 47 CFR 15.519 - Technical requirements for hand held UWB systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... information to an associated receiver. The UWB intentional radiator shall cease transmission within 10 seconds... received. An acknowledgment of reception must continue to be received by the UWB intentional radiator...

  13. 47 CFR 15.519 - Technical requirements for hand held UWB systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... information to an associated receiver. The UWB intentional radiator shall cease transmission within 10 seconds... received. An acknowledgment of reception must continue to be received by the UWB intentional radiator...

  14. 47 CFR 15.519 - Technical requirements for hand held UWB systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... information to an associated receiver. The UWB intentional radiator shall cease transmission within 10 seconds... received. An acknowledgment of reception must continue to be received by the UWB intentional radiator...

  15. UWB radar technique for arc detection in coaxial cables and waveguides

    SciTech Connect

    Maggiora, R.; Salvador, S.

    2009-11-26

    As spread spectrum technology has revolutionized the communications industry, Ultra Wide Band (UWB) technology is dramatically improving radar performances. These advanced signal processing techniques have been adapted to coaxial cables and waveguides to provide new features and enhanced performance on arc detection. UWB signals constituted by a sequence of chips (properly chosen to reduce side lobes and to improve detection accuracy) are transmitted along the transmission lines at a specified Pulse Repetition Frequency (PRF) and their echoes are received by means of directional couplers. The core of the receiver is an ultra high-speed correlator implemented in a Digital Signal Processor (DSP). When a target (arc) is detected, its position and its 'radar cross section' are calculated to be able to provide the arc position along the transmission line and to be able to classify the type of detected arc. The 'background scattering' is routinely extracted from the received signal at any pulse. This permits to be resilient to the background structure of transmission lines (bends, junctions, windows, etc.). Thanks to the localization feature, segmentation is also possible for creating sensed and non-sensed zones (for example, to be insensitive to antenna load variations)

  16. Influence of the organism interface on the breast cancer detection by UWB

    NASA Astrophysics Data System (ADS)

    Xiao, Xia; Kikkawa, Takamaro

    2008-11-01

    Ultra-wide band (UWB) imaging technique is very attractive for the early breast cancer detection based on the obvious contrast in the electrical properties of malignant tumor to the normal fatty breast tissue. The tumor can be detected by analyzing the reflecting and scattering behavior of the UWB microwaves propagating in the breast. In this study, the influence of the organism interfaces is investigated from different cases of breast configuration involving different gland shapes as well as the tumor locations. Results show that the gland structure and tumor status have large influences on the reconstructed images generated from the detected signals due to the interface varieties. The tumor information in the proposed configurations can be obtained by series signal processing including eliminating the early time response of the detected signals caused by the direct wave and the reflection from the interface between the skin and the breast fat, and compensating the path loss of the propagating signal due to the radial spreading and the attenuation in the lossy breast. The location and the number of emitters and detectors affect the quality of the reconstructed image.

  17. UWB multi-burst transmit driver for averaging receivers

    DOEpatents

    Dallum, Gregory E

    2012-11-20

    A multi-burst transmitter for ultra-wideband (UWB) communication systems generates a sequence of precisely spaced RF bursts from a single trigger event. There are two oscillators in the transmitter circuit, a gated burst rate oscillator and a gated RF burst or RF power output oscillator. The burst rate oscillator produces a relatively low frequency, i.e., MHz, square wave output for a selected transmit cycle, and drives the RF burst oscillator, which produces RF bursts of much higher frequency, i.e., GHz, during the transmit cycle. The frequency of the burst rate oscillator sets the spacing of the RF burst packets. The first oscillator output passes through a bias driver to the second oscillator. The bias driver conditions, e.g., level shifts, the signal from the first oscillator for input into the second oscillator, and also controls the length of each RF burst. A trigger pulse actuates a timing circuit, formed of a flip-flop and associated reset time delay circuit, that controls the operation of the first oscillator, i.e., how long it oscillates (which defines the transmit cycle).

  18. Improved phase-coding methods with fewer patterns for 3D shape measurement

    NASA Astrophysics Data System (ADS)

    Wang, Yajun; Chen, Xiangcheng; Huang, Lijie; Liu, Qian; Li, Lulu; Huang, Wen

    2017-10-01

    Absolute phase information is required when multiple separated objects are being measured. The recent proposed phase-coding method can effectively achieve absolute phase retrieval by embedding the fringe order information in phase domain. However, it suffers from the limitation of codewords and the requirement of more coding patterns. To overcome these problems, this paper proposed several improved phase-coding methods to solve the absolute phase with fewer patterns. The four-frame and five-frame method are suitable when the fringes are sparse, since they can respectively encode N / 2 and N fringe periods(generally N ≤ 16). If really dense fringe patterns with more than N periods are required, the improved two-step phase-coding algorithm can be adopted since it can encode about N2 / 2 fringe periods. Experiments were conducted and the results verify the success of the proposed methods.

  19. Georeferencing in Gnss-Challenged Environment: Integrating Uwb and Imu Technologies

    NASA Astrophysics Data System (ADS)

    Toth, C. K.; Koppanyi, Z.; Navratil, V.; Grejner-Brzezinska, D.

    2017-05-01

    Acquiring geospatial data in GNSS compromised environments remains a problem in mapping and positioning in general. Urban canyons, heavily vegetated areas, indoor environments represent different levels of GNSS signal availability from weak to no signal reception. Even outdoors, with multiple GNSS systems, with an ever-increasing number of satellites, there are many situations with limited or no access to GNSS signals. Independent navigation sensors, such as IMU can provide high-data rate information but their initial accuracy degrades quickly, as the measurement data drift over time unless positioning fixes are provided from another source. At The Ohio State University's Satellite Positioning and Inertial Navigation (SPIN) Laboratory, as one feasible solution, Ultra- Wideband (UWB) radio units are used to aid positioning and navigating in GNSS compromised environments, including indoor and outdoor scenarios. Here we report about experiences obtained with georeferencing a pushcart based sensor system under canopied areas. The positioning system is based on UWB and IMU sensor integration, and provides sensor platform orientation for an electromagnetic inference (EMI) sensor. Performance evaluation results are provided for various test scenarios, confirming acceptable results for applications where high accuracy is not required.

  20. 3D positioning scheme exploiting nano-scale IR-UWB orthogonal pulses

    PubMed Central

    2011-01-01

    In these days, the development of positioning technology for realizing ubiquitous environments has become one of the most important issues. The Global Positioning System (GPS) is a well-known positioning scheme, but it is not suitable for positioning in in-door/building environments because it is difficult to maintain line-of-sight condition between satellites and a GPS receiver. To such problem, various positioning methods such as RFID, WLAN, ZigBee, and Bluetooth have been developed for indoor positioning scheme. However, the majority of positioning schemes are focused on the two-dimension positioning even though three-dimension (3D) positioning information is more useful especially in indoor applications, such as smart space, U-health service, context aware service, etc. In this paper, a 3D positioning system based on mutually orthogonal nano-scale impulse radio ultra-wideband (IR-UWB) signals and cross array antenna is proposed. The proposed scheme uses nano-scale IR-UWB signals providing fine time resolution and high-resolution multiple signal specification algorithm for the time-of-arrival and the angle-of-arrival estimation. The performance is evaluated over various IEEE 802.15.4a channel models, and simulation results show the effectiveness of proposed scheme. PMID:21970578

  1. 3D positioning scheme exploiting nano-scale IR-UWB orthogonal pulses

    NASA Astrophysics Data System (ADS)

    Kim, Nammoon; Kim, Youngok

    2011-10-01

    In these days, the development of positioning technology for realizing ubiquitous environments has become one of the most important issues. The Global Positioning System (GPS) is a well-known positioning scheme, but it is not suitable for positioning in in-door/building environments because it is difficult to maintain line-of-sight condition between satellites and a GPS receiver. To such problem, various positioning methods such as RFID, WLAN, ZigBee, and Bluetooth have been developed for indoor positioning scheme. However, the majority of positioning schemes are focused on the two-dimension positioning even though three-dimension (3D) positioning information is more useful especially in indoor applications, such as smart space, U-health service, context aware service, etc. In this paper, a 3D positioning system based on mutually orthogonal nano-scale impulse radio ultra-wideband (IR-UWB) signals and cross array antenna is proposed. The proposed scheme uses nano-scale IR-UWB signals providing fine time resolution and high-resolution multiple signal specification algorithm for the time-of-arrival and the angle-of-arrival estimation. The performance is evaluated over various IEEE 802.15.4a channel models, and simulation results show the effectiveness of proposed scheme.

  2. A phase code for memory could arise from circuit mechanisms in entorhinal cortex

    PubMed Central

    Hasselmo, Michael E.; Brandon, Mark P.; Yoshida, Motoharu; Giocomo, Lisa M.; Heys, James G.; Fransen, Erik; Newman, Ehren L.; Zilli, Eric A.

    2009-01-01

    Neurophysiological data reveals intrinsic cellular properties that suggest how entorhinal cortical neurons could code memory by the phase of their firing. Potential cellular mechanisms for this phase coding in models of entorhinal function are reviewed. This mechanism for phase coding provides a substrate for modeling the responses of entorhinal grid cells, as well as the replay of neural spiking activity during waking and sleep. Efforts to implement these abstract models in more detailed biophysical compartmental simulations raise specific issues that could be addressed in larger scale population models incorporating mechanisms of inhibition. PMID:19656654

  3. Sensing through the wall imaging using the Army Research Lab ultra-wideband synchronous impulse reconstruction (UWB SIRE) radar

    NASA Astrophysics Data System (ADS)

    Nguyen, Lam; Ressler, Marc; Sichina, Jeffrey

    2008-04-01

    The U.S. Army Research Laboratory (ARL), as part of a mission and customer funded exploratory program, has developed a new low-frequency, ultra-wideband (UWB) synthetic aperture radar (SAR). The radar is capable of penetrating enclosed areas (buildings) and generating SAR imagery. This supports the U.S. Army's need for intelligence on the configuration, content, and human presence inside these enclosed areas. The radar system is mounted on a ground based vehicle traveling along the road and is configured with an array of antennas pointing toward the enclosed areas of interest. This paper will describe an experiment conducted recently at Aberdeen Proving Ground (APG), Maryland. In this paper we briefly describe the UWB SIRE radar and the test setup in the experiment. We will also describe the signal processing and the image techniques used to produce the SAR imagery. Finally, we will present SAR imagery of the building and its internal structure from different viewing directions.

  4. Short-Range Vital Signs Sensing Based on EEMD and CWT Using IR-UWB Radar

    PubMed Central

    Hu, Xikun; Jin, Tian

    2016-01-01

    The radar sensor described realizes healthcare monitoring capable of detecting subject chest-wall movement caused by cardiopulmonary activities and wirelessly estimating the respiration and heartbeat rates of the subject without attaching any devices to the body. Conventional single-tone Doppler radar can only capture Doppler signatures because of a lack of bandwidth information with noncontact sensors. In contrast, we take full advantage of impulse radio ultra-wideband (IR-UWB) radar to achieve low power consumption and convenient portability, with a flexible detection range and desirable accuracy. A noise reduction method based on improved ensemble empirical mode decomposition (EEMD) and a vital sign separation method based on the continuous-wavelet transform (CWT) are proposed jointly to improve the signal-to-noise ratio (SNR) in order to acquire accurate respiration and heartbeat rates. Experimental results illustrate that respiration and heartbeat signals can be extracted accurately under different conditions. This noncontact healthcare sensor system proves the commercial feasibility and considerable accessibility of using compact IR-UWB radar for emerging biomedical applications. PMID:27916877

  5. Experimental Results of Site Calibration and Sensitivity Measurements in OTR for UWB Systems

    NASA Astrophysics Data System (ADS)

    Viswanadham, Chandana; Rao, P. Mallikrajuna

    2016-08-01

    System calibration and parameter accuracy measurement of electronic support measures (ESM) systems is a major activity, carried out by electronic warfare (EW) engineers. These activities are very critical and needs good understanding in the field of microwaves, antennas, wave propagation, digital and communication domains. EW systems are broad band, built with state-of-the art electronic hardware, installed on different varieties of military platforms to guard country's security from time to time. EW systems operate in wide frequency ranges, typically in the order of thousands of MHz, hence these are ultra wide band (UWB) systems. Few calibration activities are carried within the system and in the test sites, to meet the accuracies of final specifications. After calibration, parameters are measured for their accuracies either in feed mode by injecting the RF signals into the front end or in radiation mode by transmitting the RF signals on to system antenna. To carry out these activities in radiation mode, a calibrated open test range (OTR) is necessary in the frequency band of interest. Thus site calibration of OTR is necessary to be carried out before taking up system calibration and parameter measurements. This paper presents the experimental results of OTR site calibration and sensitivity measurements of UWB systems in radiation mode.

  6. Experimental Results of Site Calibration and Sensitivity Measurements in OTR for UWB Systems

    NASA Astrophysics Data System (ADS)

    Viswanadham, Chandana; Rao, P. Mallikrajuna

    2017-06-01

    System calibration and parameter accuracy measurement of electronic support measures (ESM) systems is a major activity, carried out by electronic warfare (EW) engineers. These activities are very critical and needs good understanding in the field of microwaves, antennas, wave propagation, digital and communication domains. EW systems are broad band, built with state-of-the art electronic hardware, installed on different varieties of military platforms to guard country's security from time to time. EW systems operate in wide frequency ranges, typically in the order of thousands of MHz, hence these are ultra wide band (UWB) systems. Few calibration activities are carried within the system and in the test sites, to meet the accuracies of final specifications. After calibration, parameters are measured for their accuracies either in feed mode by injecting the RF signals into the front end or in radiation mode by transmitting the RF signals on to system antenna. To carry out these activities in radiation mode, a calibrated open test range (OTR) is necessary in the frequency band of interest. Thus site calibration of OTR is necessary to be carried out before taking up system calibration and parameter measurements. This paper presents the experimental results of OTR site calibration and sensitivity measurements of UWB systems in radiation mode.

  7. Short-Range Vital Signs Sensing Based on EEMD and CWT Using IR-UWB Radar.

    PubMed

    Hu, Xikun; Jin, Tian

    2016-11-30

    The radar sensor described realizes healthcare monitoring capable of detecting subject chest-wall movement caused by cardiopulmonary activities and wirelessly estimating the respiration and heartbeat rates of the subject without attaching any devices to the body. Conventional single-tone Doppler radar can only capture Doppler signatures because of a lack of bandwidth information with noncontact sensors. In contrast, we take full advantage of impulse radio ultra-wideband (IR-UWB) radar to achieve low power consumption and convenient portability, with a flexible detection range and desirable accuracy. A noise reduction method based on improved ensemble empirical mode decomposition (EEMD) and a vital sign separation method based on the continuous-wavelet transform (CWT) are proposed jointly to improve the signal-to-noise ratio (SNR) in order to acquire accurate respiration and heartbeat rates. Experimental results illustrate that respiration and heartbeat signals can be extracted accurately under different conditions. This noncontact healthcare sensor system proves the commercial feasibility and considerable accessibility of using compact IR-UWB radar for emerging biomedical applications.

  8. A Novel UWB Antenna with Dual Band-Notched Characteristics

    NASA Astrophysics Data System (ADS)

    Lin, Yongfan; Liang, Jiangang; Wu, Goucheng; Xu, Zhiyong; Niu, Xuebin

    2015-11-01

    In this article, started from analyzing the basic principle of band-notched characteristics, a feasibly method used for band-notched antenna is demonstrated and the equivalent circuit for this method is designed. A novel UWB antenna is designed. Based on this method, two stubs which can be equivalent to shorted stubs in parallel configuration are added to realize dual band-notched characteristics. Simulated and measured results all show that the UWB antenna yields an impendence bandwidth of 2.0-10.6 GHz by defining VSWR ≦ 2, and two obvious band-notched functions (3.27-3.83 GHz, 4.60-5.90 GHz) occur at the working bandwidth of WIMAX (3.3-3.7 GHz) and HiperLAN/2 (5.15-5.35 GHz, 5.47-5.725 GHz), so the electromagnetic interference between UWB application and WIMAX, HiperLAN/2 can be suppressed.

  9. Hybrid UWB and WiMAX radio-over-multi-mode fibre for in-building optical networks

    NASA Astrophysics Data System (ADS)

    Perez, J.; Llorente, R.

    2014-01-01

    In this paper the use of hybrid WiMedia-defined ultra-wideband (UWB) and IEEE 802.16d WiMAX radio-over-fibre is proposed and experimentally demonstrated for multi-mode based in-building optical networks with the advantage of great immunity to optical transmission impairments. In the proposed approach, spectral coexistence of both signals must be achieved with negligible mutual interference. The experimental study performed addressed an indoor configuration with 50 μm multi-mode fibres (MMF) and 850 nm vertical-cavity surface-emitting laser (VCSEL) transmitters. The results indicate that the impact of the wireless convergence in radio-over-multi-mode fibre (RoMMF) is significant for UWB transmissions, mainly due to MMF dispersion and electrooptical (EO) devices with limited bandwidth. On the other hand, WiMAX transmission is feasible for a 300 m MMF and 30 m wireless link in the presence of UWB, with -31 dBm WiMAX EVM.

  10. Studies on an Iterative Frequency Domain Channel Estimation Technique for MIMO-UWB Communications

    NASA Astrophysics Data System (ADS)

    Takanashi, Masaki; Ogawa, Yasutaka; Nishimura, Toshihiko; Ohgane, Takeo

    MIMO (Multiple-Input Multiple-Output) technologies have attracted much interest for high-rate and high-capacity wireless communications. MIMO technologies under frequency-selective fading environments (wideband MIMO technologies) have also been studied. A wideband MIMO system is affected by ISI (Inter Symbol Interference) and CCI (Co-Channel Interference). Hence, we need a MIMO signal detection technique that simultaneously suppresses ISI and CCI. The OFDM system and SC-FDE (Single Carrier-Frequency Domain Equalization) techniques are often used for suppressing ISI. By employing these techniques with the ZF (Zero Forcing) or the MMSE (Minimum Mean Square Error) spatial filtering technique, we can cancel both ISI and CCI. To use ZF or MMSE, we need channel state information for calculating the receive weights. Although an LS (Least Square) channel estimation technique has been proposed for MIMO-OFDM systems, it needs a large estimation matrix at the receiver side to obtain sufficient estimation performance in heavy multipath environments. However, the use of a large matrix increases computational complexity and the circuit size. We use frequency domain channel estimation to solve these problems and propose an iterative method for achieving better estimation performance. In this paper, we assume the use of a MIMO-UWB system that employs a UWB-IR (Ultra-Wideband Impulse Radio) scheme with the FDE technique as the wideband wireless transmission scheme for heavy multipath environments, and we evaluate the iterative frequency domain channel estimation through computer simulations and computational complexity calculations.

  11. UWB Two-Cluster AOA Tracking Prototype System Design

    NASA Technical Reports Server (NTRS)

    Ngo, Phong H.; Arndt, D.; Phan, C.; Gross, J.; Jianjun; Rafford, Melinda

    2006-01-01

    This presentation discusses a design effort for a prototype ultra-wideband (UWB) tracking system that is currently under development at NASA Johnson Space Center (JSC). The system is being studied for use in tracking of lunar/Mars rovers during early exploration missions when satellite navigation systems are not available. The UWB technology is exploited to implement the tracking system due to its properties such as fine time resolution, low power spectral density and multipath immunity. A two cluster prototype design using commercially available UWB radios is employed to implement the Angle of Arrival (AOA) tracking methodology in this design effort. In order to increase the tracking range, low noise amplifiers (LNA) and high gain horns are used at the receiving sides. Field tests were conducted jointly with the Science and Crew Operation Utility Testbed (SCOUT) vehicle near the Meteor Crater in Arizona to test the tracking capability for a moving target in an operational environment. These tests demonstrate that the UWB tracking system can co-exist with other on-board radio frequency (RF) communication systems (such as Global Positioning System (GPS), video, voice and telemetry systems), and that a tracking resolution less than 1% of the range can be achieved.

  12. Security authentication with a three-dimensional optical phase code using random forest classifier: an overview

    NASA Astrophysics Data System (ADS)

    Markman, Adam; Carnicer, Artur; Javidi, Bahram

    2017-05-01

    We overview our recent work [1] on utilizing three-dimensional (3D) optical phase codes for object authentication using the random forest classifier. A simple 3D optical phase code (OPC) is generated by combining multiple diffusers and glass slides. This tag is then placed on a quick-response (QR) code, which is a barcode capable of storing information and can be scanned under non-uniform illumination conditions, rotation, and slight degradation. A coherent light source illuminates the OPC and the transmitted light is captured by a CCD to record the unique signature. Feature extraction on the signature is performed and inputted into a pre-trained random-forest classifier for authentication.

  13. Encrypted optical storage with wavelength-key and random phase codes.

    PubMed

    Matoba, O; Javidi, B

    1999-11-10

    An encrypted optical memory system that uses a wavelength code as well as input and Fourier-plane random phase codes is proposed. Original data are illuminated by a coherent light source with a specified wavelength and are then encrypted with two random phase codes before being stored holographically in a photorefractive material. Successful decryption requires the use of a readout beam with the same wavelength as that used in the recording, in addition to the correct phase key in the Fourier plane. The wavelength selectivity of the proposed system is evaluated numerically. We show that the number of available wavelength keys depends on the correlation length of the phase key in the Fourier plane. Preliminary experiments of encryption and decryption of optical memory in a LiNbO(3):Fe photorefractive crystal are demonstrated.

  14. Minimum peak range sidelobe filters for binary phase-coded waveforms

    NASA Astrophysics Data System (ADS)

    Zoraster, S.

    1980-01-01

    Linear programming techniques are utilized to determine the optimal filter weights for minimizing the peak range sidelobes of a binary phase-coded waveform. The resulting filter is compared with the filter obtained by use of the least square approximation to the ideal inverse filter. For a test case using the 13-element Barker code the linear programming filter is found to have peak sidelobes as much as 5 dB lower than the least squares filter of the same length.

  15. Standardization on body area network and a prototype system based on UWB.

    PubMed

    Li, Huan-Bang; Kohno, Ryuji

    2011-10-01

    Body area network (BAN) is a promising wireless technology that realizes wireless connectivity among vital signal sensors deployed on human body. Monitoring various vital signals collected through BAN provides an efficient way to lower disease occurrence rate and reduce medical expenditure. Task Group 6 (TG6) within the IEEE 802 Local and Metropolitan Area Network Standards Committee is developing a BAN standard, i.e., IEEE 802.15.6. In which, specifications of three physical layers (PHYs) and a single common medium access control (MAC) are being drafted. The standardization process has been continuing for several years in the Task Group 6 (TG6) under Working Group 15 (WG). In this paper, we describe the up-to-date status of IEEE 802.15.6 standardization. Some main specifications under drafting are presented. Moreover, as an effort of implementing a BAN model, a prototype BAN system based on the high band of ultra-wideband (UWB) is demonstrated.

  16. Phase coding by grid cells in unconstrained environments: Two-dimensional (2D) phase precession

    PubMed Central

    Climer, Jason R.; Newman, Ehren L.; Hasselmo, Michael E.

    2014-01-01

    Action potential timing is thought to play a critical role in neural representation. For example, theta phase precession is a robust phenomenon exhibited by spatial cells of the rat entorhinal-hippocampal circuit. In phase precession, the time a neuron fires relative to the phase of theta rhythm (6-10Hz) oscillations in the local field potential reduces uncertainty about the position of the animal. This relationship between neural firing and behavior has made precession an important constraint for hypothetical mechanisms of temporal coding. However, challenges exist in identifying what regulates the spike timing of these cells. We have developed novel analytical techniques for mapping between behavior and neural firing that provide sufficient sensitivity to examine features of grid cell phase coding in open environments. Here, we show robust, omnidirectional phase precession by entorhinal grid cells in openfield enclosures. We present evidence that full phase precession persists regardless of how close the animal comes to the center of a firing field. We found many conjunctive grid cells, previously thought to be phase locked, also exhibit phase coding. However, we were unable to detect directional or field specific phase coding predicted by some variants of models. Finally, we present data that suggests bursting of layer II grid cells contributes to the bimodality of phase precession. We discuss implications of these observations for models of temporal coding and propose the utility of these techniques in other domains where behavior is aligned to neural spiking. PMID:23718553

  17. Small Patch Antennas for UWB Wireless Body Area Network

    NASA Astrophysics Data System (ADS)

    Klemm, M.; Tröster, G.

    This paper presents the transient characteristics of an aperture-stacked patch antenna (ASPA) and its miniaturized version. These antennas were designed for ultra-wideband (UWB) body area network (BAN) applications, to operate within the 3 to 6 GHz frequency band. The APSA with large ground plane size has a planar dimensions 70 × 70 mm2, the smaller version has dimensions 32 × 26 mm2. The latest yields 85% reduction of the antenna surface. Time- and frequency-domain characteristics of these antennas were calculated in a transmission mode (Tx) and also in a complete, two-antenna (Tx-Rx) system. We have used 3 different waveforms to drive the antenna: gaussian pulse (duration-250 ps), monocycle pulse (duration-300 ps) and defined wavelet (duration-650 ps). The received pulses have very similar shapes (fidelity >90%), but they differ in the voltage amplitudes. Results show that the highest received voltage (best transmission efficiency) is achieved for the pulse with the closest spectrum to the antenna's transfer function characteristic. In order to disclose the effects of the human body proximity, two body models were built and full-wave FDTD method was employed to carry out the simulations. Significant changes of the UWB antenna performance when close to the body were identified. The most important effects are the seriously decreased radiation efficiency (16 to 34%) and different (from that in a free space) shape of the antenna transfer function. The first one can have the impact on low power implementations of UWB wearable radios; the second one discloses possible influence on the UWB systems design (especially for template receivers). The impact of the human body on antenna characteristics was identified to be a key factor in UWB body-worn antenna design.

  18. Outdoor propagation analysis of ultrawideband signals

    NASA Astrophysics Data System (ADS)

    Schiavone, Guy A.; Wahid, Parveen; Palaniappan, Ravi; Tracy, Judd; Van Doorn, Eric; Lonske, Benjamin

    2003-08-01

    An ultra wide band (UWB) signal is defined as any radiation in which the 3-dB bandwidth is greater than 25% of the center frequency. UWB signals are characterized by extreme low powers and large bandwidths, which can be used for data, voice and video communication. Since UWB waveforms have very short time duration, they are relatively immune to multi-path cancellation effects. In this paper we test the performance of a simulation to model the propagation of an UWB signal in outdoor forested environment. The simulation uses a combination of Finite Difference Time Domain and ray tracing methods to simulate the UWB wave propagation. The model takes into consideration the dielectric constants of the materials of the trees and measures the signal strength for vertical and horizontal polarizations of the UWB antennas placed at various heights and distances from each other. The results of the simulation are compared to measurements obtained from tests conducted at a wooded area in Seneca Creek State Park, Gaithersburg, Maryland. It was observed that upto 150 ft distance between the transmitter and receiver, the horizontally polarized antenna system gave better signal-to-noise ratio, but at greater distances the vertically polarized antenna system gave a better signal-to-noise ration performance. Three dimensional plots of the signal strengths and the signal-to-noise ratio for various transmitter and receiver distances are plotted for the system. These are compared with experimental results and the simulation closely matched the experimental data. The results of the simulation and measurements will be used for further developing an UWB location and tracking system for outdoor environments.

  19. Enhanced Ultra-Wideband (UWB) Circular Monopole Antenna with Electromagnetic Band Gap (EBG) Surface and Director

    DTIC Science & Technology

    2014-08-01

    enhanced UWB monopole antenna 4. Electromagnetic Band Gap Surface (EBG) Design EBG surfaces act as perfect magnetic conductors (PMCs) at a resonance...Enhanced Ultra-Wideband ( UWB ) Circular Monopole Antenna with Electromagnetic Band Gap (EBG) Surface and Director by Amir I Zaghloul, Youn M...DATES COVERED (From - To) 4. TITLE AND SUBTITLE Enhanced Ultra-Wideband ( UWB ) Circular Monopole Antenna with Electromagnetic Band Gap (EBG

  20. Multi-pulse multi-delay (MPMD) multiple access modulation for UWB

    DOEpatents

    Dowla, Farid U.; Nekoogar, Faranak

    2007-03-20

    A new modulation scheme in UWB communications is introduced. This modulation technique utilizes multiple orthogonal transmitted-reference pulses for UWB channelization. The proposed UWB receiver samples the second order statistical function at both zero and non-zero lags and matches the samples to stored second order statistical functions, thus sampling and matching the shape of second order statistical functions rather than just the shape of the received pulses.

  1. Design and Performance Analysis of a UWB Tracking System for Space Applications

    DTIC Science & Technology

    2005-01-01

    This paper discusses an ultra-wideband (UWB) tracking system design effort for a freeflying video camera system for aid in inspection around the International Space Station and the Space Shuttle. The UWB technology is exploited to implement the tracking system due to its properties such as high data rate, fine time resolution, low power spectral density and multipath immunity. A system design using commercially available UWB products

  2. Hand-Based Gesture Recognition for Vehicular Applications Using IR-UWB Radar.

    PubMed

    Khan, Faheem; Leem, Seong Kyu; Cho, Sung Ho

    2017-04-11

    Modern cars continue to offer more and more functionalities due to which they need a growing number of commands. As the driver tries to monitor the road and the graphic user interface simultaneously, his/her overall efficiency is reduced. In order to reduce the visual attention necessary for monitoring, a gesture-based user interface is very important. In this paper, gesture recognition for a vehicle through impulse radio ultra-wideband (IR-UWB) radar is discussed. The gestures can be used to control different electronic devices inside a vehicle. The gestures are based on human hand and finger motion. We have implemented a real-time version using only one radar sensor. Studies on gesture recognition using IR-UWB radar have rarely been carried out, and some studies are merely simple methods using the magnitude of the reflected signal or those whose performance deteriorates largely due to changes in distance or direction. In this study, we propose a new hand-based gesture recognition algorithm that works robustly against changes in distance or direction while responding only to defined gestures by ignoring meaningless motions. We used three independent features, i.e., variance of the probability density function (pdf) of the magnitude histogram, time of arrival (TOA) variation and the frequency of the reflected signal, to classify the gestures. A data fitting method is included to differentiate between gesture signals and unintended hand or body motions. We have used the clustering technique for the classification of the gestures. Moreover, the distance information is used as an additional input parameter to the clustering algorithm, such that the recognition technique will not be vulnerable to distance change. The hand-based gesture recognition proposed in this paper would be a key technology of future automobile user interfaces.

  3. Hand-Based Gesture Recognition for Vehicular Applications Using IR-UWB Radar

    PubMed Central

    Khan, Faheem; Leem, Seong Kyu; Cho, Sung Ho

    2017-01-01

    Modern cars continue to offer more and more functionalities due to which they need a growing number of commands. As the driver tries to monitor the road and the graphic user interface simultaneously, his/her overall efficiency is reduced. In order to reduce the visual attention necessary for monitoring, a gesture-based user interface is very important. In this paper, gesture recognition for a vehicle through impulse radio ultra-wideband (IR-UWB) radar is discussed. The gestures can be used to control different electronic devices inside a vehicle. The gestures are based on human hand and finger motion. We have implemented a real-time version using only one radar sensor. Studies on gesture recognition using IR-UWB radar have rarely been carried out, and some studies are merely simple methods using the magnitude of the reflected signal or those whose performance deteriorates largely due to changes in distance or direction. In this study, we propose a new hand-based gesture recognition algorithm that works robustly against changes in distance or direction while responding only to defined gestures by ignoring meaningless motions. We used three independent features, i.e., variance of the probability density function (pdf) of the magnitude histogram, time of arrival (TOA) variation and the frequency of the reflected signal, to classify the gestures. A data fitting method is included to differentiate between gesture signals and unintended hand or body motions. We have used the clustering technique for the classification of the gestures. Moreover, the distance information is used as an additional input parameter to the clustering algorithm, such that the recognition technique will not be vulnerable to distance change. The hand-based gesture recognition proposed in this paper would be a key technology of future automobile user interfaces. PMID:28398267

  4. A Detailed Algorithm for Vital Sign Monitoring of a Stationary/Non-Stationary Human through IR-UWB Radar

    PubMed Central

    Khan, Faheem; Cho, Sung Ho

    2017-01-01

    The vital sign monitoring through Impulse Radio Ultra-Wide Band (IR-UWB) radar provides continuous assessment of a patient’s respiration and heart rates in a non-invasive manner. In this paper, IR UWB radar is used for monitoring respiration and the human heart rate. The breathing and heart rate frequencies are extracted from the signal reflected from the human body. A Kalman filter is applied to reduce the measurement noise from the vital signal. An algorithm is presented to separate the heart rate signal from the breathing harmonics. An auto-correlation based technique is applied for detecting random body movements (RBM) during the measurement process. Experiments were performed in different scenarios in order to show the validity of the algorithm. The vital signs were estimated for the signal reflected from the chest, as well as from the back side of the body in different experiments. The results from both scenarios are compared for respiration and heartbeat estimation accuracy. PMID:28165416

  5. Towards Contactless Silent Speech Recognition Based on Detection of Active and Visible Articulators Using IR-UWB Radar

    PubMed Central

    Shin, Young Hoon; Seo, Jiwon

    2016-01-01

    People with hearing or speaking disabilities are deprived of the benefits of conventional speech recognition technology because it is based on acoustic signals. Recent research has focused on silent speech recognition systems that are based on the motions of a speaker’s vocal tract and articulators. Because most silent speech recognition systems use contact sensors that are very inconvenient to users or optical systems that are susceptible to environmental interference, a contactless and robust solution is hence required. Toward this objective, this paper presents a series of signal processing algorithms for a contactless silent speech recognition system using an impulse radio ultra-wide band (IR-UWB) radar. The IR-UWB radar is used to remotely and wirelessly detect motions of the lips and jaw. In order to extract the necessary features of lip and jaw motions from the received radar signals, we propose a feature extraction algorithm. The proposed algorithm noticeably improved speech recognition performance compared to the existing algorithm during our word recognition test with five speakers. We also propose a speech activity detection algorithm to automatically select speech segments from continuous input signals. Thus, speech recognition processing is performed only when speech segments are detected. Our testbed consists of commercial off-the-shelf radar products, and the proposed algorithms are readily applicable without designing specialized radar hardware for silent speech processing. PMID:27801867

  6. Towards Contactless Silent Speech Recognition Based on Detection of Active and Visible Articulators Using IR-UWB Radar.

    PubMed

    Shin, Young Hoon; Seo, Jiwon

    2016-10-29

    People with hearing or speaking disabilities are deprived of the benefits of conventional speech recognition technology because it is based on acoustic signals. Recent research has focused on silent speech recognition systems that are based on the motions of a speaker's vocal tract and articulators. Because most silent speech recognition systems use contact sensors that are very inconvenient to users or optical systems that are susceptible to environmental interference, a contactless and robust solution is hence required. Toward this objective, this paper presents a series of signal processing algorithms for a contactless silent speech recognition system using an impulse radio ultra-wide band (IR-UWB) radar. The IR-UWB radar is used to remotely and wirelessly detect motions of the lips and jaw. In order to extract the necessary features of lip and jaw motions from the received radar signals, we propose a feature extraction algorithm. The proposed algorithm noticeably improved speech recognition performance compared to the existing algorithm during our word recognition test with five speakers. We also propose a speech activity detection algorithm to automatically select speech segments from continuous input signals. Thus, speech recognition processing is performed only when speech segments are detected. Our testbed consists of commercial off-the-shelf radar products, and the proposed algorithms are readily applicable without designing specialized radar hardware for silent speech processing.

  7. Amplify-and-Forward Cooperative Diversity for Green UWB-Based WBSNs

    PubMed Central

    2013-01-01

    This paper proposes a novel green cooperative diversity technique based on suboptimal template-based ultra-wideband (UWB) wireless body sensor networks (WBSNs) using amplify-and-forward (AF) relays. In addition, it analyzes the bit-error-rate (BER) performance of the proposed nodes. The analysis is based on the moment-generating function (MGF) of the total signal-to-noise ratio (SNR) at the destination. It also provides an approximate value for the total SNR. The analysis studies the performance of equally correlated binary pulse position modulation (EC-BPPM) assuming the sinusoidal and square suboptimal template pulses. Numerical results are provided for the performance evaluation of optimal and suboptimal template-based nodes with and without relay cooperation. Results show that one relay node provides ~23 dB performance enhancement at 1e − 3 BER, which mitigates the effect of the nondesirable non-line-of-sight (NLOS) links in WBSNs. PMID:24307880

  8. Amplify-and-forward cooperative diversity for green UWB-based WBSNs.

    PubMed

    Shaban, Heba; Abou El-Nasr, Mohamad

    2013-01-01

    This paper proposes a novel green cooperative diversity technique based on suboptimal template-based ultra-wideband (UWB) wireless body sensor networks (WBSNs) using amplify-and-forward (AF) relays. In addition, it analyzes the bit-error-rate (BER) performance of the proposed nodes. The analysis is based on the moment-generating function (MGF) of the total signal-to-noise ratio (SNR) at the destination. It also provides an approximate value for the total SNR. The analysis studies the performance of equally correlated binary pulse position modulation (EC-BPPM) assuming the sinusoidal and square suboptimal template pulses. Numerical results are provided for the performance evaluation of optimal and suboptimal template-based nodes with and without relay cooperation. Results show that one relay node provides ~23 dB performance enhancement at 1e - 3 BER, which mitigates the effect of the nondesirable non-line-of-sight (NLOS) links in WBSNs.

  9. Input-Dependent Frequency Modulation of Cortical Gamma Oscillations Shapes Spatial Synchronization and Enables Phase Coding

    PubMed Central

    Lowet, Eric; Roberts, Mark; Hadjipapas, Avgis; Peter, Alina; van der Eerden, Jan; De Weerd, Peter

    2015-01-01

    Fine-scale temporal organization of cortical activity in the gamma range (∼25–80Hz) may play a significant role in information processing, for example by neural grouping (‘binding’) and phase coding. Recent experimental studies have shown that the precise frequency of gamma oscillations varies with input drive (e.g. visual contrast) and that it can differ among nearby cortical locations. This has challenged theories assuming widespread gamma synchronization at a fixed common frequency. In the present study, we investigated which principles govern gamma synchronization in the presence of input-dependent frequency modulations and whether they are detrimental for meaningful input-dependent gamma-mediated temporal organization. To this aim, we constructed a biophysically realistic excitatory-inhibitory network able to express different oscillation frequencies at nearby spatial locations. Similarly to cortical networks, the model was topographically organized with spatially local connectivity and spatially-varying input drive. We analyzed gamma synchronization with respect to phase-locking, phase-relations and frequency differences, and quantified the stimulus-related information represented by gamma phase and frequency. By stepwise simplification of our models, we found that the gamma-mediated temporal organization could be reduced to basic synchronization principles of weakly coupled oscillators, where input drive determines the intrinsic (natural) frequency of oscillators. The gamma phase-locking, the precise phase relation and the emergent (measurable) frequencies were determined by two principal factors: the detuning (intrinsic frequency difference, i.e. local input difference) and the coupling strength. In addition to frequency coding, gamma phase contained complementary stimulus information. Crucially, the phase code reflected input differences, but not the absolute input level. This property of relative input-to-phase conversion, contrasting with latency

  10. Input-dependent frequency modulation of cortical gamma oscillations shapes spatial synchronization and enables phase coding.

    PubMed

    Lowet, Eric; Roberts, Mark; Hadjipapas, Avgis; Peter, Alina; van der Eerden, Jan; De Weerd, Peter

    2015-02-01

    Fine-scale temporal organization of cortical activity in the gamma range (∼25-80Hz) may play a significant role in information processing, for example by neural grouping ('binding') and phase coding. Recent experimental studies have shown that the precise frequency of gamma oscillations varies with input drive (e.g. visual contrast) and that it can differ among nearby cortical locations. This has challenged theories assuming widespread gamma synchronization at a fixed common frequency. In the present study, we investigated which principles govern gamma synchronization in the presence of input-dependent frequency modulations and whether they are detrimental for meaningful input-dependent gamma-mediated temporal organization. To this aim, we constructed a biophysically realistic excitatory-inhibitory network able to express different oscillation frequencies at nearby spatial locations. Similarly to cortical networks, the model was topographically organized with spatially local connectivity and spatially-varying input drive. We analyzed gamma synchronization with respect to phase-locking, phase-relations and frequency differences, and quantified the stimulus-related information represented by gamma phase and frequency. By stepwise simplification of our models, we found that the gamma-mediated temporal organization could be reduced to basic synchronization principles of weakly coupled oscillators, where input drive determines the intrinsic (natural) frequency of oscillators. The gamma phase-locking, the precise phase relation and the emergent (measurable) frequencies were determined by two principal factors: the detuning (intrinsic frequency difference, i.e. local input difference) and the coupling strength. In addition to frequency coding, gamma phase contained complementary stimulus information. Crucially, the phase code reflected input differences, but not the absolute input level. This property of relative input-to-phase conversion, contrasting with latency codes

  11. UWB SAR system PULSAR: new generator and antenna developments

    NASA Astrophysics Data System (ADS)

    Delmonte, Philippe; Dubois, Cyril; Andrieu, Jo"l.; Beillard, Bruno; Lalande, Michèle; Bertrand, Valérie; Jecko, Bernard; Pecastaing, Laurent; Gibert, Alain; Paillol, Jean; Domens, Pierre; Guillerey, Régis; Monnier, Francis; Legoff, Marc

    2003-08-01

    PULSAR is an Ultra Wide-Band short pulse Radar developed by the CELAR (French Technical Centre for Armament Electronics) and the IRCOM (Research Institute of Microwave and Optical Communications) in order to detect foliage and ground concealed targets. One of the most promising mission of such potential radar is the detection of buried and surface land mine fields. An instrumentation measurement system has been designed and implemented. This paper deals with the recent development efforts on this system, specially on a new pulse generator and a new UWB antenna. Recently, the LGE (Laboratoire de Génie Electrique) has developed a high voltage pulse coaxial generator. These recent developments allowed to increase the pulse output voltage and the pulse rise time. The new UWB antenna is able to support a very high voltage; the bandwidth and the gain are greater than the ones of the previous antenna.

  12. UWB channel estimation using new generating TR transceivers

    DOEpatents

    Nekoogar, Faranak [San Ramon, CA; Dowla, Farid U [Castro Valley, CA; Spiridon, Alex [Palo Alto, CA; Haugen, Peter C [Livermore, CA; Benzel, Dave M [Livermore, CA

    2011-06-28

    The present invention presents a simple and novel channel estimation scheme for UWB communication systems. As disclosed herein, the present invention maximizes the extraction of information by incorporating a new generation of transmitted-reference (Tr) transceivers that utilize a single reference pulse(s) or a preamble of reference pulses to provide improved channel estimation while offering higher Bit Error Rate (BER) performance and data rates without diluting the transmitter power.

  13. Chip Discrimination for UWB Impulse Radio Networks in Multipath Channels

    DTIC Science & Technology

    2005-08-01

    IEEE, 92(2):295 – 311, Feb. 2004. [8] J. R. Foerster, M. Pendergrass, A. F. Molisch . A Channel Model for Ultrawideband Indoor Communication...Multipath Channels. In Proc. IRE, volume 46, pages 555 – 570, March 1958. [24] D. Cassioli, M. Z. Win, F. Vatalaro, A. F. Molisch . Performance of Low...M. Z. Win, F. Vatalaro, A. F. Molisch . Effects of Spreading Bandwidth on the Performance of UWB RAKE Receivers. IEEE International Conference on

  14. Progress in UWB generation with linear silicon switches

    NASA Astrophysics Data System (ADS)

    Cardwell, Kendall W.; Giorgi, David M.; McIntyre, Iain A.; Solone, Paul J.; Stuurman, K.; Zucker, Oved S. F.

    1993-06-01

    The use of linear photoconductive switches rather than nonlinear switches for the generation of Ultra-Wide-Band (UWB) pulses provides advantages such as jitter-free operation, low losses, and a reduction of the electrical and mechanical stresses in the switch. These advantages lead to the operation of many switches in series and/or parallel, higher average powers and longer lifetimes. Energy Compression Research Corporation (ECR) has demonstrated an advanced UWB source based on light activated silicon switches (LASS). The UWB source consists of a single LASS device mounted on a low impedance (< 0.5 (Omega) ) microstrip transmission line and a high fidelity impedance transformer connected to a 50 (Omega) coaxial connection. The voltage was measured at low impedance and 50 (Omega) to verify the efficiency and fidelity of the impedance transformer. After a transformation of 110:1 in impedance, the measurement at the end of the transformer verified that pulse rise-time was less than 100 ps and the overall efficiency was 50%. The system was tested up to 10 kV into 50 (Omega) before connector breakdown limited further increase. Larger powers can be radiated if the transformer is directly connected to the antenna.

  15. Independent theta phase coding accounts for CA1 population sequences and enables flexible remapping

    PubMed Central

    Chadwick, Angus; van Rossum, Mark CW; Nolan, Matthew F

    2015-01-01

    Hippocampal place cells encode an animal's past, current, and future location through sequences of action potentials generated within each cycle of the network theta rhythm. These sequential representations have been suggested to result from temporally coordinated synaptic interactions within and between cell assemblies. Instead, we find through simulations and analysis of experimental data that rate and phase coding in independent neurons is sufficient to explain the organization of CA1 population activity during theta states. We show that CA1 population activity can be described as an evolving traveling wave that exhibits phase coding, rate coding, spike sequences and that generates an emergent population theta rhythm. We identify measures of global remapping and intracellular theta dynamics as critical for distinguishing mechanisms for pacemaking and coordination of sequential population activity. Our analysis suggests that, unlike synaptically coupled assemblies, independent neurons flexibly generate sequential population activity within the duration of a single theta cycle. DOI: http://dx.doi.org/10.7554/eLife.03542.001 PMID:25643396

  16. Phase-amplitude coupling supports phase coding in human ECoG

    PubMed Central

    Watrous, Andrew J; Deuker, Lorena; Fell, Juergen; Axmacher, Nikolai

    2015-01-01

    Prior studies have shown that high-frequency activity (HFA) is modulated by the phase of low-frequency activity. This phenomenon of phase-amplitude coupling (PAC) is often interpreted as reflecting phase coding of neural representations, although evidence for this link is still lacking in humans. Here, we show that PAC indeed supports phase-dependent stimulus representations for categories. Six patients with medication-resistant epilepsy viewed images of faces, tools, houses, and scenes during simultaneous acquisition of intracranial recordings. Analyzing 167 electrodes, we observed PAC at 43% of electrodes. Further inspection of PAC revealed that category specific HFA modulations occurred at different phases and frequencies of the underlying low-frequency rhythm, permitting decoding of categorical information using the phase at which HFA events occurred. These results provide evidence for categorical phase-coded neural representations and are the first to show that PAC coincides with phase-dependent coding in the human brain. DOI: http://dx.doi.org/10.7554/eLife.07886.001 PMID:26308582

  17. 47 CFR 15.517 - Technical requirements for indoor UWB systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false Technical requirements for indoor UWB systems. 15.517 Section 15.517 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Ultra-Wideband Operation § 15.517 Technical requirements for indoor UWB systems. (a) Operation...

  18. 47 CFR 15.517 - Technical requirements for indoor UWB systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 1 2014-10-01 2014-10-01 false Technical requirements for indoor UWB systems. 15.517 Section 15.517 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Ultra-Wideband Operation § 15.517 Technical requirements for indoor UWB systems. (a) Operation...

  19. UWB EMI To Aircraft Radios: Field Evaluation on Operational Commercial Transport Airplanes. Volume 1

    NASA Technical Reports Server (NTRS)

    Oria, A. J. (Editor); Ely, Jay J.; Martin, Warren L.; Shaver, Timothy W.; Fuller, Gerald L.; Zimmerman, John; Fuschino, Robert L.; Larsen, William E.

    2005-01-01

    Ultrawideband (UWB) transmitters may soon be integrated into a wide variety of portable electronic devices (PEDs) that passengers routinely carry on board commercial airplanes. Airlines and the FAA will have difficulty controlling passenger use of UWB transmitters during flights with current airline policies and existing wireless product standards. The aeronautical community is concerned as to whether evolving FCC UWB rules are adequate to protect legacy and emerging aeronautical radio systems from electromagnetic interference (EMI) from emerging UWB products. To address these concerns, the NASA Office of Space Communications and Chief Spectrum Managers assembled a multidisciplinary team from NASA LaRC, NASA JPL, NASA ARC, FAA, United Airlines, Sky West Airlines, and Eagles Wings Inc. to carry out a comprehensive series of tests aimed at determining the nature and extent of any EMI to aeronautical communication and navigation systems from UWB devices meeting FCCapproved and proposed levels for unlicensed handheld transmitters.

  20. High speed Radix-4 soft-decision Viterbi decoder for MB-OFDM UWB system

    NASA Astrophysics Data System (ADS)

    Liang, Guixuan; Portilla, Jorge; Riesgo, Teresa

    2013-05-01

    In this paper, a 64 state soft decision Viterbi Decoder (VD) system by using a high speed radix-4 Add Compare Select (ACS) architecture is presented. The proposed VD system can support different data rate (from 53.5 Mbps to 480 Mbps) for Multiband Orthogonal Frequency-division Multiplexing (MB-OFDM) Ultra-Wideband (UWB) system when implemented onto the FPGA board. The proposed VD employs efficient two steps Radix 4 architecture, which is responsible of calculating two steps of 64 state Radix 4 Branch Metrics (BM) within one clock cycle. The branch metrics are calculated using a uniform distance measurement algorithm, which equals to the symbol itself when compared to logic-0 and equal to its one's complement when compared to logic-1. By employing the modified Modulo Normalization algorithm, it is possible to use only a 10- bit memory block to restore each of the 64 state metrics, with the advantage of avoiding errors caused by overflow during the updating process for state metrics, and simplifying the comparator circuit of the ACS unit. The Two Pointer Even Algorithm, which is considered to be very simple and more hardware-efficient than the register exchange algorithm, is used for tracing back the survivor sequence and output the decoded data stream. 3-bit soft decision input sequences are used for gathering the experimental results. The sampling frequency of the MBOFDM UWB system is 528 MHz, by using the proposed two steps Radix 4 VD architecture we can process 4 input signals in parallel within one clock cycle, therefore only 132 MHz operating frequency is needed for the proposed VD system. This will dramatically reduce the dynamic power consumption for hardware implementation. Final results of the implementation show that the proposed VD architecture can support a maximum working frequency of 152.5 MHz on Xilinx XUPV5-LX110T Evaluation Platform.

  1. A 128-channel 6 mW wireless neural recording IC with spike feature extraction and UWB transmitter.

    PubMed

    Chae, Moo Sung; Yang, Zhi; Yuce, Mehmet R; Hoang, Linh; Liu, Wentai

    2009-08-01

    This paper reports a 128-channel neural recording integrated circuit (IC) with on-the-fly spike feature extraction and wireless telemetry. The chip consists of eight 16-channel front-end recording blocks, spike detection and feature extraction digital signal processor (DSP), ultra wideband (UWB) transmitter, and on-chip bias generators. Each recording channel has amplifiers with programmable gain and bandwidth to accommodate different types of biological signals. An analog-to-digital converter (ADC) shared by 16 amplifiers through time-multiplexing results in a balanced trade-off between the power consumption and chip area. A nonlinear energy operator (NEO) based spike detector is implemented for identifying spikes, which are further processed by a digital frequency-shaping filter. The computationally efficient spike detection and feature extraction algorithms attribute to an auspicious DSP implementation on-chip. UWB telemetry is designed to wirelessly transfer raw data from 128 recording channels at a data rate of 90 Mbit/s. The chip is realized in 0.35 mum complementary metal-oxide-semiconductor (CMOS) process with an area of 8.8 x 7.2 mm(2) and consumes 6 mW by employing a sequential turn-on architecture that selectively powers off idle analog circuit blocks. The chip has been tested for electrical specifications and verified in an ex vivo biological environment.

  2. Integrated navigation fusion strategy of INS/UWB for indoor carrier attitude angle and position synchronous tracking.

    PubMed

    Fan, Qigao; Wu, Yaheng; Hui, Jing; Wu, Lei; Yu, Zhenzhong; Zhou, Lijuan

    2014-01-01

    In some GPS failure conditions, positioning for mobile target is difficult. This paper proposed a new method based on INS/UWB for attitude angle and position synchronous tracking of indoor carrier. Firstly, error model of INS/UWB integrated system is built, including error equation of INS and UWB. And combined filtering model of INS/UWB is researched. Simulation results show that the two subsystems are complementary. Secondly, integrated navigation data fusion strategy of INS/UWB based on Kalman filtering theory is proposed. Simulation results show that FAKF method is better than the conventional Kalman filtering. Finally, an indoor experiment platform is established to verify the integrated navigation theory of INS/UWB, which is geared to the needs of coal mine working environment. Static and dynamic positioning results show that the INS/UWB integrated navigation system is stable and real-time, positioning precision meets the requirements of working condition and is better than any independent subsystem.

  3. Proof-of-principle experiment of reference-frame-independent quantum key distribution with phase coding

    PubMed Central

    Liang, Wen-Ye; Wang, Shuang; Li, Hong-Wei; Yin, Zhen-Qiang; Chen, Wei; Yao, Yao; Huang, Jing-Zheng; Guo, Guang-Can; Han, Zheng-Fu

    2014-01-01

    We have demonstrated a proof-of-principle experiment of reference-frame-independent phase coding quantum key distribution (RFI-QKD) over an 80-km optical fiber. After considering the finite-key bound, we still achieve a distance of 50 km. In this scenario, the phases of the basis states are related by a slowly time-varying transformation. Furthermore, we developed and realized a new decoy state method for RFI-QKD systems with weak coherent sources to counteract the photon-number-splitting attack. With the help of a reference-frame-independent protocol and a Michelson interferometer with Faraday rotator mirrors, our system is rendered immune to the slow phase changes of the interferometer and the polarization disturbances of the channel, making the procedure very robust. PMID:24402550

  4. Decoding of responses to mixed frequency and phase coded visual stimuli using multiset canonical correlation analysis.

    PubMed

    Suefusa, Kaori; Tanaka, Toshihisa

    2016-08-01

    Brain-computer interfacing (BCI) based on steady-state visual evoked potentials (SSVEPs) is one of the most practical BCIs because of its high recognition accuracies and little training of a user. Mixed frequency and phase coding which can implement a number of commands and achieve a high information transfer rate (ITR) has recently been gaining much attention. In order to implement mixed-coded SSVEP-BCI as a reliable interface, it is important to detect commands fast and accurately. This paper presents a novel method to recognize mixed-coded SSVEPs which achieves high performance. The method employs multiset canonical correlation analysis to obtain spatial filters which enhance SSVEP components. An experiment with a mixed-coded SSVEP-BCI was conducted to evaluate performance of the proposed method compared with the previous work. The experimental results showed that the proposed method achieved significantly higher command recognition accuracy and ITR than the state-of-the-art.

  5. Proof-of-principle experiment of reference-frame-independent quantum key distribution with phase coding.

    PubMed

    Liang, Wen-Ye; Wang, Shuang; Li, Hong-Wei; Yin, Zhen-Qiang; Chen, Wei; Yao, Yao; Huang, Jing-Zheng; Guo, Guang-Can; Han, Zheng-Fu

    2014-01-09

    We have demonstrated a proof-of-principle experiment of reference-frame-independent phase coding quantum key distribution (RFI-QKD) over an 80-km optical fiber. After considering the finite-key bound, we still achieve a distance of 50 km. In this scenario, the phases of the basis states are related by a slowly time-varying transformation. Furthermore, we developed and realized a new decoy state method for RFI-QKD systems with weak coherent sources to counteract the photon-number-splitting attack. With the help of a reference-frame-independent protocol and a Michelson interferometer with Faraday rotator mirrors, our system is rendered immune to the slow phase changes of the interferometer and the polarization disturbances of the channel, making the procedure very robust.

  6. Proof-of-principle experiment of reference-frame-independent quantum key distribution with phase coding

    NASA Astrophysics Data System (ADS)

    Liang, Wen-Ye; Wang, Shuang; Li, Hong-Wei; Yin, Zhen-Qiang; Chen, Wei; Yao, Yao; Huang, Jing-Zheng; Guo, Guang-Can; Han, Zheng-Fu

    2014-01-01

    We have demonstrated a proof-of-principle experiment of reference-frame-independent phase coding quantum key distribution (RFI-QKD) over an 80-km optical fiber. After considering the finite-key bound, we still achieve a distance of 50 km. In this scenario, the phases of the basis states are related by a slowly time-varying transformation. Furthermore, we developed and realized a new decoy state method for RFI-QKD systems with weak coherent sources to counteract the photon-number-splitting attack. With the help of a reference-frame-independent protocol and a Michelson interferometer with Faraday rotator mirrors, our system is rendered immune to the slow phase changes of the interferometer and the polarization disturbances of the channel, making the procedure very robust.

  7. M-type potassium conductance controls the emergence of neural phase codes: a combined experimental and neuron modelling study.

    PubMed

    Kwag, Jeehyun; Jang, Hyun Jae; Kim, Mincheol; Lee, Sujeong

    2014-10-06

    Rate and phase codes are believed to be important in neural information processing. Hippocampal place cells provide a good example where both coding schemes coexist during spatial information processing. Spike rate increases in the place field, whereas spike phase precesses relative to the ongoing theta oscillation. However, what intrinsic mechanism allows for a single neuron to generate spike output patterns that contain both neural codes is unknown. Using dynamic clamp, we simulate an in vivo-like subthreshold dynamics of place cells to in vitro CA1 pyramidal neurons to establish an in vitro model of spike phase precession. Using this in vitro model, we show that membrane potential oscillation (MPO) dynamics is important in the emergence of spike phase codes: blocking the slowly activating, non-inactivating K+ current (IM), which is known to control subthreshold MPO, disrupts MPO and abolishes spike phase precession. We verify the importance of adaptive IM in the generation of phase codes using both an adaptive integrate-and-fire and a Hodgkin-Huxley (HH) neuron model. Especially, using the HH model, we further show that it is the perisomatically located IM with slow activation kinetics that is crucial for the generation of phase codes. These results suggest an important functional role of IM in single neuron computation, where IM serves as an intrinsic mechanism allowing for dual rate and phase coding in single neurons.

  8. UWB tomosynthesis of objects in mediums with metal inclusions

    NASA Astrophysics Data System (ADS)

    Yakubov, V. P.; Shipilov, S. E.; Sukhanov, D. Ya; Minin, I. V.; Minin, O. V.

    2017-08-01

    Radiowave tomography of dielectric objects containing metal inclusions is a rather complex problem, since the scattering of waves by dielectric inhomogeneities occurs against the background of substantially stronger reflections from metal parts, even if they are geometrically small. The arising features of obtaining a tomogram in such conditions, including overcoming of disguising by reinforcing ribbons and the appearance of locational shadows at different depths, are discussed in the paper. Herewith principled importance to achieve high focusing of UWB radiation by tomosynthesis is noted on the basis of direct experimental data.

  9. Hex-Sided Rounded Dipole Antenna (HSRDA) For UWB Applications

    NASA Astrophysics Data System (ADS)

    Singhal, Sarthak; Verma, Nand Kishor; Singh, Amit Kumar

    2016-03-01

    A hex-sided rounded dipole antenna (HSRDA) for UWB applications is presented. It is designed by the addition of semi-elliptical patch sections at the edges of a square bow-tie antenna. The antenna structure is fed by a modified microstrip feedline for better impedance matching. An impedance bandwidth of 2.9-11.4 GHz is achieved. The antenna structure has quasi omnidirectional radiation patterns and reasonable gain over the same frequency range. A good agreement between the experimental and simulation results is observed. The proposed antenna structure has miniaturized size for the same bandwidth as compared to already reported antenna structures.

  10. Generation of FCC-compliant and background-free millimeter-wave ultrawideband signal based on nonlinear polarization rotation in a highly nonlinear fiber.

    PubMed

    Li, Wei; Wang, Wen Ting; Sun, Wen Hui; Liu, Jian Guo; Zhu, Ning Hua

    2014-05-05

    We propose a novel approach to generating millimeter-wave (MMW) ultrawideband (UWB) signal based on nonlinear polarization rotation (NPR) in a highly nonlinear fiber (HNLF). The MMW UWB signal is background-free by eliminating the baseband frequency components using an optical filter. The proposed scheme is theoretically analyzed and experimentally verified. The generated MMW UWB signal centered at 25.5 GHz has a 10-dB bandwidth of 7 GHz from 22 to 29 GHz, which fully satisfies the spectral mask regulated by the Federal Communications Commission (FCC).

  11. Breath Activity Monitoring With Wearable UWB Radars: Measurement and Analysis of the Pulses Reflected by the Human Body.

    PubMed

    Pittella, Erika; Pisa, Stefano; Cavagnaro, Marta

    2016-07-01

    Measurements of ultrawideband (UWB) pulses reflected by the human body are conducted to evidence the differences in the received signal time behaviors due to respiration phases, and to experimentally verify previously obtained numerical results on the body's organs responsible for pulse reflection. Two experimental setups are used. The first one is based on a commercially available impulse radar system integrated on a single chip, while the second one implements an indirect time-domain reflectometry technique using a vector network analyzer controlled by a LabVIEW virtual instrument running on a laptop. When the UWB source is placed close to the human body, a small reflection due to the lung boundaries is present in the received pulse well distanced in time from the reflection due to the air-skin interface; this reflection proved to be linked to the different respiration phases. The changes in the reflected pulse could be used to detect, through wearable radar systems, lung movements associated with the breath activity. The development of a wearable radar system is of great importance because it allows the breath activity sensing without interfering with the subject daily activities.

  12. Entropy-Based TOA Estimation and SVM-Based Ranging Error Mitigation in UWB Ranging Systems

    PubMed Central

    Yin, Zhendong; Cui, Kai; Wu, Zhilu; Yin, Liang

    2015-01-01

    The major challenges for Ultra-wide Band (UWB) indoor ranging systems are the dense multipath and non-line-of-sight (NLOS) problems of the indoor environment. To precisely estimate the time of arrival (TOA) of the first path (FP) in such a poor environment, a novel approach of entropy-based TOA estimation and support vector machine (SVM) regression-based ranging error mitigation is proposed in this paper. The proposed method can estimate the TOA precisely by measuring the randomness of the received signals and mitigate the ranging error without the recognition of the channel conditions. The entropy is used to measure the randomness of the received signals and the FP can be determined by the decision of the sample which is followed by a great entropy decrease. The SVM regression is employed to perform the ranging-error mitigation by the modeling of the regressor between the characteristics of received signals and the ranging error. The presented numerical simulation results show that the proposed approach achieves significant performance improvements in the CM1 to CM4 channels of the IEEE 802.15.4a standard, as compared to conventional approaches. PMID:26007726

  13. Entropy-Based TOA Estimation and SVM-Based Ranging Error Mitigation in UWB Ranging Systems.

    PubMed

    Yin, Zhendong; Cui, Kai; Wu, Zhilu; Yin, Liang

    2015-05-21

    The major challenges for Ultra-wide Band (UWB) indoor ranging systems are the dense multipath and non-line-of-sight (NLOS) problems of the indoor environment. To precisely estimate the time of arrival (TOA) of the first path (FP) in such a poor environment, a novel approach of entropy-based TOA estimation and support vector machine (SVM) regression-based ranging error mitigation is proposed in this paper. The proposed method can estimate the TOA precisely by measuring the randomness of the received signals and mitigate the ranging error without the recognition of the channel conditions. The entropy is used to measure the randomness of the received signals and the FP can be determined by the decision of the sample which is followed by a great entropy decrease. The SVM regression is employed to perform the ranging-error mitigation by the modeling of the regressor between the characteristics of received signals and the ranging error. The presented numerical simulation results show that the proposed approach achieves significant performance improvements in the CM1 to CM4 channels of the IEEE 802.15.4a standard, as compared to conventional approaches.

  14. Interrogation of electrical connector faults using miniaturized UWB sources

    NASA Astrophysics Data System (ADS)

    Tokgöz, Çaǧata; Dardona, Sameh

    2017-01-01

    A diagnostic method for the detection, identification, and characterization of precursors of faults due to partial insertion of pin-socket contacts within electrical connectors commonly used in avionics systems is presented. It is demonstrated that a miniaturized ultrawideband (UWB) source and a minispectrum analyzer can be employed to measure resonant frequency shifts in connector S parameters as a small and low-cost alternative to a large and expensive network analyzer. The transfer function of an electrical connector is represented as a ratio of the spectra measured using the spectrum analyzer with and without the connector. Alternatively, the transfer function is derived in terms of the connector S parameters and the reflection coefficients at both ports of the connector. The transfer function data obtained using this derivation agreed well with its representation as a measured spectral ratio. The derivation enabled the extraction of the connector S parameters from the measured transfer function data as a function of the insertion depth of a pin-socket contact within the connector. In comparison with the S parameters measured directly using a network analyzer at multiple insertion depths, the S parameters extracted from the measured transfer function showed consistent and reliable representation of the electrical connector fault. The results demonstrate the potential of integrating a low-cost miniaturized UWB device into a connector harness for real-time detection of precursors to partially inserted connector faults.

  15. Capacity of UWB wireless channel for neural recording systems.

    PubMed

    El Khaled, Mohamad; Bahrami, Hadi; Fortier, Paul; Gosselin, Benoit; Rusch, Leslie Ann

    2014-01-01

    Ultra wide-band (UWB) short-range communication systems are valuable in medical technology, particularly for implanted devices, due to their low-power consumption, low cost, small size and high data rates. Monitoring of neural responses in the brain requires high data rate if we target a system supporting a large number of sensors. In this work, we are interested in the evaluation of the capacity of the ultra wide-band (UWB) channel that we could exploit using a realistic model of the biological channel. The channel characteristics are examined under two scenarios that are related to TX antenna placements. Using optimal power spectrum allocation (OPSA) at the transmitter side, we have computed this capacity by taking into account the fading characteristics of the channel. The results show the pertinence of the optimal power spectrum allocation for this type of channel. An improvement by a factor of 2 to 3 over a uniform power spectrum allocation (UPSA) when the SNR <; 0 dB was obtained. When the SNR is > 40 dB, both approaches give similar results. Antennas placement is examined under two scenarios having contrasting power constraints.

  16. 79 GHz UWB automotive short range radar - Spectrum allocation and technology trends

    NASA Astrophysics Data System (ADS)

    Bloecher, H.-L.; Sailer, A.; Rollmann, G.; Dickmann, J.

    2009-05-01

    Automotive UWB (Ultra-Wideband) short range radar (SSR) is on the market as a key technology for novel comfort and safety systems. SiGe based 79 GHz UWB SRR will be a definite candidate for the long term substitution of the 24 GHz UWB SRR. This paper will give an overview of the finished BMBF joint project KOKON and the recently started successing project RoCC, which concentrate on the development of this technology and sensor demonstrators. In both projects, the responsibilities of Daimler AG deal with application based sensor specification, test and evaluation of realized sensor demonstrators. Recent UWB SRR frequency regulation approaches and activitites will be introduced. Furthermore, some first results of Daimler activities within RoCC will be presented, dealing with the packaging and operation of these sensors within the complex car environment.

  17. Distortion effects in a switch array UWB radar for time-lapse imaging of human heartbeats

    NASA Astrophysics Data System (ADS)

    Brovoll, Sverre; Berger, Tor; Aardal, Åyvind; Lande, Tor S.; Hamran, Svein-Erik

    2014-05-01

    Cardiovascular diseases (CVD) are a major cause of deaths all over the world. Microwave radar can be an alternative sensor for heart diagnostics and monitoring in modern healthcare that aids early detection of CVD symptoms. In this paper measurements from a switch array radar system are presented. This UWB system operates below 3 GHz and does time-lapse imaging of the beating heart inside the human body. The array consists of eight fat dipole elements. With a switch system, every possible sequence of transmit/receive element pairs can be selected to build a radar image from the recordings. To make the radar waves penetrate the human tissue, the antenna array is placed in contact with the body. Removal of the direct signal leakage through the antennas and body surface are done by high-pass (HP) filtering of the data prior to image processing. To analyze the results, measurements of moving spheres in air and simulations are carried out. We see that removal of the direct signal introduces amplitude distortion in the images. In addition, the effect of small target motion between the collection times of data from the individual elements is analyzed. With low pulse repetition frequency (PRF) this motion will distort the image. By using data from real measurements of heart motion in simulations, we analyze how the PRF and the antenna geometry influence this distortions.

  18. PCA-based artifact removal algorithm for stroke detection using UWB radar imaging.

    PubMed

    Ricci, Elisa; di Domenico, Simone; Cianca, Ernestina; Rossi, Tommaso; Diomedi, Marina

    2016-09-16

    Stroke patients should be dispatched at the highest level of care available in the shortest time. In this context, a transportable system in specialized ambulances, able to evaluate the presence of an acute brain lesion in a short time interval (i.e., few minutes), could shorten delay of treatment. UWB radar imaging is an emerging diagnostic branch that has great potential for the implementation of a transportable and low-cost device. Transportability, low cost and short response time pose challenges to the signal processing algorithms of the backscattered signals as they should guarantee good performance with a reasonably low number of antennas and low computational complexity, tightly related to the response time of the device. The paper shows that a PCA-based preprocessing algorithm can: (1) achieve good performance already with a computationally simple beamforming algorithm; (2) outperform state-of-the-art preprocessing algorithms; (3) enable a further improvement in the performance (and/or decrease in the number of antennas) by using a multistatic approach with just a modest increase in computational complexity. This is an important result toward the implementation of such a diagnostic device that could play an important role in emergency scenario.

  19. A Rugged Ultra-Wideband (UWB) Circular Planar Monopole for Multichannel Radar

    DTIC Science & Technology

    2016-03-01

    ARL-TR-7630 ● MAR 2016 US Army Research Laboratory A Rugged Ultra-Wideband (UWB) Circular Planar Monopole for Multichannel Radar... Laboratory A Rugged Ultra-Wideband (UWB) Circular Planar Monopole for Multichannel Radar by Seth A McCormick, Amir I Zaghloul, and Arthur C Harrison...0018185.1.1 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) US Army Research Laboratory ATTN: RDRL-SER-M

  20. Time-Reversal Based Range Extension technique for Ultra-wideband (UWB) Sensors and Applications in Tactical Communications and Networking

    DTIC Science & Technology

    2010-01-28

    DISTRIBUTION /AVAILABILITY STATEMENT release for public distribution . 13. SUPPLEMENTARY NOTES 14. ABSTRACT This final report summarizes major project...Communication System 57 4.2.4 Simulation Results 59 4.2.5 Conclusions 61 4.3 Publication List 62 III Technical Impacts 65 4.4 UWB MIMO ...Testbed 67 4.4.1 2-By-l UWB MISO Testbed Description 67 4.4.2 Potential UWB MIMO Testbed 67 CONTENTS 7 5 Waveform Diveristy 69 6 Wideband

  1. Time-Reversal Based Range Extension Technique for Ultra-Wideband (UWB) Sensors and Applications in Tactical Communications and Networking

    DTIC Science & Technology

    2008-10-16

    TOJ Tennessee Tech UNIVERSITY Time-Reversal Based Range Extension Technique for Ultra-wideband (UWB) Sensors and Applications in Tactical...for Ultra-wideband (UWB) Sensors and Applications in Tactical Communications and Networking 5a. CONTRACT NUMBER 5b. GRANT NUMBER N00014-07-1...and ARO—is to build a general purpose testbed with time reversal capability at the transmitter side. The envisioned application is for UWB sensors

  2. UWB Wind Turbine Blade Deflection Sensing for Wind Energy Cost Reduction

    PubMed Central

    Zhang, Shuai; Jensen, Tobias Lindstrøm; Franek, Ondrej; Eggers, Patrick C. F.; Olesen, Kim; Byskov, Claus; Pedersen, Gert Frølund

    2015-01-01

    A new application of utilizing ultra-wideband (UWB) technology to sense wind turbine blade deflections is introduced in this paper for wind energy cost reduction. The lower UWB band of 3.1–5.3 GHz is applied. On each blade, there will be one UWB blade deflection sensing system, which consists of two UWB antennas at the blade root and one UWB antenna at the blade tip. The detailed topology and challenges of this deflection sensing system are addressed. Due to the complexity of the problem, this paper will first realize the on-blade UWB radio link in the simplest case, where the tip antenna is situated outside (and on the surface of) a blade tip. To investigate this case, full-blade time-domain measurements are designed and conducted under different deflections. The detailed measurement setups and results are provided. If the root and tip antenna locations are properly selected, the first pulse is always of sufficient quality for accurate estimations under different deflections. The measured results reveal that the blade tip-root distance and blade deflection can be accurately estimated in the complicated and lossy wireless channels around a wind turbine blade. Some future research topics on this application are listed finally. PMID:26274964

  3. UWB Wind Turbine Blade Deflection Sensing for Wind Energy Cost Reduction.

    PubMed

    Zhang, Shuai; Jensen, Tobias Lindstrøm; Franek, Ondrej; Eggers, Patrick C F; Olesen, Kim; Byskov, Claus; Pedersen, Gert Frølund

    2015-08-12

    A new application of utilizing ultra-wideband (UWB) technology to sense wind turbine blade deflections is introduced in this paper for wind energy cost reduction. The lower UWB band of 3.1-5.3 GHz is applied. On each blade, there will be one UWB blade deflection sensing system, which consists of two UWB antennas at the blade root and one UWB antenna at the blade tip. The detailed topology and challenges of this deflection sensing system are addressed. Due to the complexity of the problem, this paper will first realize the on-blade UWB radio link in the simplest case, where the tip antenna is situated outside (and on the surface of) a blade tip. To investigate this case, full-blade time-domain measurements are designed and conducted under different deflections. The detailed measurement setups and results are provided. If the root and tip antenna locations are properly selected, the first pulse is always of sufficient quality for accurate estimations under different deflections. The measured results reveal that the blade tip-root distance and blade deflection can be accurately estimated in the complicated and lossy wireless channels around a wind turbine blade. Some future research topics on this application are listed finally.

  4. FM-UWB: Towards a Robust, Low-Power Radio for Body Area Networks

    PubMed Central

    Kopta, Vladimir; Farserotu, John; Enz, Christian

    2017-01-01

    The Frequency Modulated Ultra-Wideband (FM-UWB) is known as a low-power, low-complexity modulation scheme targeting low to moderate data rates in applications such as wireless body area networks. In this paper, a thorough review of all FM-UWB receivers and transmitters reported in literature is presented. The emphasis is on trends in power reduction that exhibit an improvement by a factor 20 over the past eight years, showing the high potential of FM-UWB. The main architectural and circuit techniques that have led to this improvement are highlighted. Seldom explored potential of using higher data rates and more complex modulations is demonstrated as a way to increase energy efficiency of FM-UWB. Multi-user communication over a single Radio Frequency (RF) channel is explored in more depth and multi-channel transmission is proposed as an extension of standard FM-UWB. The two techniques provide means of decreasing network latency, improving performance, and allow the FM-UWB to accommodate the increasing number of sensor nodes in the emerging applications such as High-Density Wireless Sensor Networks. PMID:28481248

  5. FM-UWB: Towards a Robust, Low-Power Radio for Body Area Networks.

    PubMed

    Kopta, Vladimir; Farserotu, John; Enz, Christian

    2017-05-06

    The Frequency Modulated Ultra-Wideband (FM-UWB) is known as a low-power, low-complexity modulation scheme targeting low to moderate data rates in applications such as wireless body area networks. In this paper, a thorough review of all FM-UWB receivers and transmitters reported in literature is presented. The emphasis is on trends in power reduction that exhibit an improvement by a factor 20 over the past eight years, showing the high potential of FM-UWB. The main architectural and circuit techniques that have led to this improvement are highlighted. Seldom explored potential of using higher data rates and more complex modulations is demonstrated as a way to increase energy efficiency of FM-UWB. Multi-user communication over a single Radio Frequency (RF) channel is explored in more depth and multi-channel transmission is proposed as an extension of standard FM-UWB. The two techniques provide means of decreasing network latency, improving performance, and allow the FM-UWB to accommodate the increasing number of sensor nodes in the emerging applications such as High-Density Wireless Sensor Networks.

  6. GPS/UWB/MEMS-IMU tightly coupled navigation with improved robust Kalman filter

    NASA Astrophysics Data System (ADS)

    Li, Zengke; Chang, Guobin; Gao, Jingxiang; Wang, Jian; Hernandez, Alberto

    2016-12-01

    The integration of Global Positioning System (GPS) with Inertial Navigation System (INS) has been very intensively developed and widely applied in multiple areas. To further enhance the reliability and availability of GPS/INS integrated navigation in GPS challenging environment, range observation through ultra-wideband (UWB) is introduced in GPS/INS tightly coupled navigation. An improved robust Kalman filter is proposed and used to resist the influence of gross error from UWB observation in GPS/UWB/IMU tightly coupled navigation. The variance of the squared Mahalanobis distance in moving window is calculated, which brings as new judgement factor for gross errors in order to decrease the rate of false outlier identification. A simulation analysis shows that the improved robust Kalman filter is able to correctly identify gross errors and the rate of false judgment as zero. In order to validate the new robust filter, a real experiment is conducted. The results indicate that the improved robust Kalman filter used in GPS/UWB/INS tightly coupled navigation is able to remove the harmful effect of gross error in UWB observation. It clearly illustrates that the improved robust Kalman filter is very effective, and all the simulated small and large gross errors added to UWB distance observation are successfully identified.

  7. A Novel Triangular Shaped UWB Fractal Antenna Using Circular Slot

    NASA Astrophysics Data System (ADS)

    Shahu, Babu Lal; Pal, Srikanta; Chattoraj, Neela

    2016-03-01

    The article presents the design of triangular shaped fractal based antenna with circular slot for ultra wideband (UWB) application. The antenna is fed using microstrip line and has overall dimension of 24×24×1.6 mm3. The proposed antenna is covering the wide frequency bandwidth of 2.99-11.16 GHz and is achieved using simple fractal based triangular-circular geometries and asymmetrical ground plane. The antenna is designed and parametrical studies are performed using method of moment (MOM) based Full Wave Electromagnetic (EM) software Simulator Zeland IE3D. The prototype of proposed antenna is fabricated and tested to compare the simulated and measured results of various antenna parameters. The antenna has good impedance bandwidth, nearly constant gain and stable radiation pattern. Measured return loss shows fair agreement with simulated one. Also measured group delay variation obtained is less than 1.0 ns, which proves good time domain behavior of the proposed antenna.

  8. A Novel Triangular Shaped UWB Fractal Antenna Using Circular Slot

    NASA Astrophysics Data System (ADS)

    Shahu, Babu Lal; Pal, Srikanta; Chattoraj, Neela

    2016-03-01

    The article presents the design of triangular shaped fractal based antenna with circular slot for ultra wideband (UWB) application. The antenna is fed using microstrip line and has overall dimension of 24×24×1.6 mm3. The proposed antenna is covering the wide frequency bandwidth of 2.99-11.16 GHz and is achieved using simple fractal based triangular-circular geometries and asymmetrical ground plane. The antenna is designed and parametrical studies are performed using method of moment (MOM) based Full Wave Electromagnetic (EM) software Simulator Zeland IE3D. The prototype of proposed antenna is fabricated and tested to compare the simulated and measured results of various antenna parameters. The antenna has good impedance bandwidth, nearly constant gain and stable radiation pattern. Measured return loss shows fair agreement with simulated one. Also measured group delay variation obtained is less than 1.0 ns, which proves good time domain behavior of the proposed antenna.

  9. Very compact quad band-notched UWB monopole antenna

    NASA Astrophysics Data System (ADS)

    Wu, Ling; Xia, Yingqing; Ye, Lei; Li, Lingzhi

    2016-10-01

    A very compact UWB antenna with four notched bands is proposed. The antenna consists of a rectangular radiating patch with a half circle at bottom, a tapered microstrip feed-line, and a semielliptical ground plane. With a pair of Lshaped slots, complementary co-directional SRR on the patch and a pair of L-shaped slots on the ground plane, four notched bands are created to prevent interference from WiMAX /WLAN/X-band. Experimental results show that the designed antenna, with compact size 20×30mm2, has an operating band(VSWR<2) from 2.7 to 20GHz,except four stop bands of 3.1 3.7GHz, 5.13 5.48GHz, 5.74 6.04GHz, 7.3 7.96GHz. And good radiation patterns within the operating band have been observed.

  10. Application of power transformation and moments in time based UWB ranging

    NASA Astrophysics Data System (ADS)

    Liu, Wenyan; Huang, Xiaotao

    2016-04-01

    For ultra-wideband (UWB) ranging, TOA estimation with the energy detection (ED) receiver is to detect the energy sample that contains the first path (FP) signal in dense multipath. Threshold crossing (TC) is used frequently. However, it is difficult to determine the threshold. Some threshold setting methods are based on constant false alarm rate (CFAR) and the chi-squared distribution. However, the distribution is complicated. Moreover, it depends on the degree of freedom (DOF). If the DOF used is wrong, it will degrade the detection performance. The study bypasses the distribution. We first examine the distribution of the output of the ED receiver after power transformation. Based on the new characteristics of the transformed data and approximate distributions, we propose some practical TOA estimation methods. Similarly, the moments of the output of the ED receiver, such as the second or one-third order moments, are also analysed and used. The proposed methods are easy to implement and can achieve about the same ranging performance with methods based on the chi-squared distribution. We provide both theoretical and simulation results to prove their effectiveness.

  11. Obstacle avoidance and concealed target detection using the Army Research Lab ultra-wideband synchronous impulse reconstruction (UWB SIRE) forward imaging radar

    NASA Astrophysics Data System (ADS)

    Nguyen, Lam; Wong, David; Ressler, Marc; Koenig, Francois; Stanton, Brian; Smith, Gregory; Sichina, Jeffrey; Kappra, Karl

    2007-04-01

    The U.S. Army Research Laboratory (ARL), as part of a mission and customer funded exploratory program, has developed a new low-frequency, ultra-wideband (UWB) synthetic aperture radar (SAR) for forward imaging to support the Army's vision of an autonomous navigation system for robotic ground vehicles. These unmanned vehicles, equipped with an array of imaging sensors, will be tasked to help detect man-made obstacles such as concealed targets, enemy minefields, and booby traps, as well as other natural obstacles such as ditches, and bodies of water. The ability of UWB radar technology to help detect concealed objects has been documented in the past and could provide an important obstacle avoidance capability for autonomous navigation systems, which would improve the speed and maneuverability of these vehicles and consequently increase the survivability of the U. S. forces on the battlefield. One of the primary features of the radar is the ability to collect and process data at combat pace in an affordable, compact, and lightweight package. To achieve this, the radar is based on the synchronous impulse reconstruction (SIRE) technique where several relatively slow and inexpensive analog-to-digital (A/D) converters are used to sample the wide bandwidth of the radar signals. We conducted an experiment this winter at Aberdeen Proving Ground (APG) to support the phenomenological studies of the backscatter from positive and negative obstacles for autonomous robotic vehicle navigation, as well as the detection of concealed targets of interest to the Army. In this paper, we briefly describe the UWB SIRE radar and the test setup in the experiment. We will also describe the signal processing and the forward imaging techniques used in the experiment. Finally, we will present imagery of man-made obstacles such as barriers, concertina wires, and mines.

  12. Photonics-assistant spectra shaping of ultra-wideband signals for dynamic spectrum access in cognitive network

    NASA Astrophysics Data System (ADS)

    Zheng, Jianyu; Zhu, Ninghua; Wang, Lixian; Wang, Hui; Du, Yuanxin; Liu, Jianguo

    2012-11-01

    The dynamic control for the spectra of the Ultra-wideband (UWB) signals, which is the key for implementing the dynamic spectrum access in the cognitive radio, is still a challenge due to the limited processing speed of the electronic devices. In this paper, we have summarized our recent work about controlling the spectrum shape of the UWB signals in optical domain, in addition to reviewing the other groups' related research work. The experiment setups and results based on nonlinear dynamics of the optoelectronic oscillator and transfer response of the phase or polarization-to-intensity convertor will be described in detail respectively, in which the controllable frequency suppress for the optical UWB signals at specific frequency positions were implemented. Particularly, the UWB pulse with the special shape, which corresponds to the 5-GHz band-rejection in frequency domain, was generated in order to avoid the interference between UWB and Wireless Fidelity system in practice. In addition, the UWB signals whose center frequency could be continuously tuned and converted up to the frequency range of millimeter wave were generated by utilizing the polarization modulator based optical switch. The areas for future development and the challenge of implementing these techniques for the applications in practice will also be discussed.

  13. Staggered Costas signals

    NASA Astrophysics Data System (ADS)

    Freedman, Avraham; Levanon, Nadav

    1986-11-01

    A radar signal, based on coherent processing of a train of staggered Costas (1984) bursts is based on a minimum number of collocation of their individual ambiguity function sidelobe peaks. The resulting ambiguity function combines qualities of both 'thumbtack' and 'bed of nails' signals. Comparison with linear-FM, V-FM, and complementary phase coded signals is given, as well as comparison with hybrid signals consisting of both phase and frequency coding.

  14. Matched filter design optimisation for UWB receiver for sensor network application

    NASA Astrophysics Data System (ADS)

    Naik, Rohit; Singh, Jugdutt; Veljanovski, Ronny

    2005-12-01

    Ultra Wideband (UWB) communications is one of the possible solutions for future wireless personal area network (WPAN) applications. The Federal Communications Commission (FCC), in the USA, allocated 7.5 GHz of unlicensed frequency bandwidth from 3.1 GHz to 10.6 GHz for UWB communication. It is an available spectrum which can be utilised for data communication using different technologies complying with FCC regulations. This paper presents a brief overview of the world wide regulations and Institute of Electrical and Electronic Engineers (IEEE) standardisation updates for UWB. It also focuses on the wireless sensor network application and the use of UWB communications in biomedical sensor networks. The paper aims at the design and implementation of an optimised pulsed matched filter (OPMF) used in the digital backend of a UWB radio. The optimisations are performed at the architectural and circuit level in order to reduce hardware complexity and reduced power. The OPMF is successfully implemented using the application specific integrated circuit (ASIC) design methodology and the results are compared with those obtained in previous implementation. The OPMF implementation presented in this paper yields improved characteristics such as reduction in area, almost 25% power reduction and better timing.

  15. A framework for UWB-based communication and location tracking systems for wireless sensor networks.

    PubMed

    Chóliz, Juan; Hernández, Angela; Valdovinos, Antonio

    2011-01-01

    Ultra wideband (UWB) radio technology is nowadays one of the most promising technologies for medium-short range communications. It has a wide range of applications including wireless sensor networks (WSN) with simultaneous data transmission and location tracking. The combination of location and data transmission is important in order to increase flexibility and reduce the cost and complexity of the system deployment. In this scenario, accuracy is not the only evaluation criteria, but also the amount of resources associated to the location service, as it has an impact not only on the location capacity of the system but also on the sensor data transmission capacity. Although several studies can be found in the literature addressing UWB-based localization, these studies mainly focus on distance estimation and position calculation algorithms. Practical aspects such as the design of the functional architecture, the procedure for the transmission of the associated information between the different elements of the system, and the need of tracking multiple terminals simultaneously in various application scenarios, are generally omitted. This paper provides a complete system level evaluation of a UWB-based communication and location system for Wireless Sensor Networks, including aspects such as UWB-based ranging, tracking algorithms, latency, target mobility and MAC layer design. With this purpose, a custom simulator has been developed, and results with real UWB equipment are presented too.

  16. Performance Evaluation of a UWB-RFID System for Potential Space Applications

    NASA Technical Reports Server (NTRS)

    Phan, Chan T.; Arndt, D.; Ngo, P.; Gross, J.; Ni, Jianjun; Rafford, Melinda

    2006-01-01

    This talk presents a brief overview of the ultra-wideband (UWB) RFID system with emphasis on the performance evaluation of a commercially available UWB-RFID system. There are many RFID systems available today, but many provide just basic identification for auditing and inventory tracking. For applications that require high precision real time tracking, UWB technology has been shown to be a viable solution. The use of extremely short bursts of RF pulses offers high immunity to interference from other RF systems, precise tracking due to sub-nanosecond time resolution, and robust performance in multipath environments. The UWB-RFID system Sapphire DART (Digital Active RFID & Tracking) will be introduced in this talk. Laboratory testing using Sapphire DART is performed to evaluate its capability such as coverage area, accuracy, ease of operation, and robustness. Performance evaluation of this system in an operational environment (a receiving warehouse) for inventory tracking is also conducted. Concepts of using the UWB-RFID technology to track astronauts and assets are being proposed for space exploration.

  17. Electromagnetic and thermal effects of IR-UWB wireless implant systems on the human head.

    PubMed

    Thotahewa, Kasun M S; Redouté, Jean-Michel; Yuce, Mehmet R

    2013-01-01

    The usage of implanted wireless transmitting devices inside the human body has become widely popular in recent years. Applications such as multi-channel neural recording systems require high data rates in the wireless transmission link. Because of the inherent advantages provided by Impulse-Radio Ultra Wide Band (IR-UWB) such as high data rate capability, low power consumption and small form factor, there has been an increased research interest in using IR-UWB for bio-medical implant applications. Hence it has become imperative to analyze the electromagnetic effects caused by the use of IR-UWB when it is operated in or near the human body. This paper reports the electromagnetic effects of head implantable transmitting devices operating based on Impulse Radio Ultra Wide Band (IR-UWB) wireless technology. Simulations illustrate the performance of an implantable UWB antenna tuned to operate at 4 GHz with an -10 dB bandwidth of approximately 1 GHz when it is implanted in a human head model. Specific Absorption Rate (SAR), Specific Absorption (SA) and temperature increase are analyzed to compare the compliance of the transmitting device with international safety regulations.

  18. Photonic generation of ultra-wideband signals by direct current modulation on SOA section of an SOA-integrated SGDBR laser.

    PubMed

    Lv, Hui; Yu, Yonglin; Shu, Tan; Huang, Dexiu; Jiang, Shan; Barry, Liam P

    2010-03-29

    Photonic ultra-wideband (UWB) pulses are generated by direct current modulation of a semiconductor optical amplifier (SOA) section of an SOA-integrated sampled grating distributed Bragg reflector (SGDBR) laser. Modulation responses of the SOA section of the laser are first simulated with a microwave equivalent circuit model. Simulated results show a resonance behavior indicating the possibility to generate UWB signals with complex shapes in the time domain. The UWB pulse generation is then experimentally demonstrated for different selected wavelength channels with an SOA-integrated SGDBR laser.

  19. Smart container UWB sensor system for situational awareness of intrusion alarms

    DOEpatents

    Romero, Carlos E.; Haugen, Peter C.; Zumstein, James M.; Leach, Jr., Richard R.; Vigars, Mark L.

    2013-06-11

    An in-container monitoring sensor system is based on an UWB radar intrusion detector positioned in a container and having a range gate set to the farthest wall of the container from the detector. Multipath reflections within the container make every point on or in the container appear to be at the range gate, allowing intrusion detection anywhere in the container. The system also includes other sensors to provide false alarm discrimination, and may include other sensors to monitor other parameters, e.g. radiation. The sensor system also includes a control subsystem for controlling system operation. Communications and information extraction capability may also be included. A method of detecting intrusion into a container uses UWB radar, and may also include false alarm discrimination. A secure container has an UWB based monitoring system

  20. Mitochondrial respiration inhibition after exposure to UWB pulses as a possible mechanism of antitumor action

    NASA Astrophysics Data System (ADS)

    Zharkova, L.; Romanchenko, I.; Bolshakov, M.; Rostov, V.

    2017-05-01

    The respiration of isolated mice liver mitochondria after exposure to nanosecond UWB pulses (0.15 - 36 kV/cm, 0.6 - 1.0 GHz centre frequency, 3 - 20 ns pulse duration) has been investigated. The respiratory control (RC, the ratio of oxygen consumption) was estimated. The possibility of mitochondrial membrane electroporation was detected as the decrease in the electrical resistance, according to the β-dispersion of the electric current. The monotonous decrease of RC after 1000 UWB pulses from 0.15 kV/cm was observed, the ohmic resistance of mitochondria suspension was reduced. The obtained data indicate the inhibitory effect of UWB pulses on a state of irradiated mitochondria and its membrane.

  1. Reconfigurable UWB Bandpass Filter with Flexible Notch Characteristics

    NASA Astrophysics Data System (ADS)

    Dhwaj, Kirti

    The thesis reports a compact tunable ultra-wideband (UWB) notch filter using hybrid microstrip and coplanar waveguide (CPW) structure. The tunable notch is implemented to filter out the wireless local area network (WLAN) channels from 5GHz to 6GHz. The proposed structure utilizes the resonance of open ended stubs to achieve transmission zeroes in the filter passband. Varactors and by-pass capacitors are then introduced for dynamic tunability of notch. Further, the electromagnetic decoupling of the two resonators leads to tunable bandwidth of notch. DC bias circuitry is implemented to control the varactor capacitances. Rejection levels up to 25 dB are attained using this technique while maintaining insertion loss levels below 2.5 dB in the passband. The reconfigurability of bandwidth is shown by maintaining a constant bandwidth of 150 MHz across the WLAN band for the notch. The filter achieves an excellent wide bandwidth (from 2.5 GHz to 8.5 GHz) using multimode-resonator (MMR) based topology which makes the filter one wavelength long at the central frequency.

  2. Breakdown Behavior of a Wireless Communication Network Under UWB Impact

    NASA Astrophysics Data System (ADS)

    Rohe, M.; Koch, M.

    Systems with high priority to safety and reliability such as monitoring systems on airports have to work properly. Fast information transmission, continuous access to databases, as well as the management of air traffic are most important for effective and safe operation. Sources of Intentional Electromagnetic Interference can be manufactured relatively easy using commercially available components by civilian persons with relevant expertise and can be used for sabotage or blackmail purposes. For analyzing the weak points of a system existing on airports, it is necessary to reproduce its setup. In this investigation a UHF transmitter of a wireless communication device is developed and its breakdown behavior to unipolar fast rise pulses (UWB) is determined. A breakdown is a non-permanent damage, but includes a type of upset, that requires manual reset or at least stops communications for some period of time. The transmitter consists of three main components connected by data cables: power supply, microcontroller, and loop antenna. The immunity tests are accomplished as a function of the electromagnetic field direction to the device using an open TEM waveguide.

  3. Breast tumor detection using UWB circular-SAR tomographic microwave imaging.

    PubMed

    Oloumi, Daniel; Boulanger, Pierre; Kordzadeh, Atefeh; Rambabu, Karumudi

    2015-01-01

    This paper describes the possibility of detecting tumors in human breast using ultra-wideband (UWB) circular synthetic aperture radar (CSAR). CSAR is a subset of SAR which is a radar imaging technique using a circular data acquisition pattern. Tomographic image reconstruction is done using a time domain global back projection technique adapted to CSAR. Experiments are conducted on a breast phantoms made of pork fat emulating normal and cancerous conditions. Preliminary experimental results show that microwave imaging of a breast phantom using UWB-CSAR is a simple and low-cost method, efficiently capable of detecting the presence of tumors.

  4. Integrated Navigation Fusion Strategy of INS/UWB for Indoor Carrier Attitude Angle and Position Synchronous Tracking

    PubMed Central

    Wu, Yaheng; Hui, Jing; Wu, Lei; Zhou, Lijuan

    2014-01-01

    In some GPS failure conditions, positioning for mobile target is difficult. This paper proposed a new method based on INS/UWB for attitude angle and position synchronous tracking of indoor carrier. Firstly, error model of INS/UWB integrated system is built, including error equation of INS and UWB. And combined filtering model of INS/UWB is researched. Simulation results show that the two subsystems are complementary. Secondly, integrated navigation data fusion strategy of INS/UWB based on Kalman filtering theory is proposed. Simulation results show that FAKF method is better than the conventional Kalman filtering. Finally, an indoor experiment platform is established to verify the integrated navigation theory of INS/UWB, which is geared to the needs of coal mine working environment. Static and dynamic positioning results show that the INS/UWB integrated navigation system is stable and real-time, positioning precision meets the requirements of working condition and is better than any independent subsystem. PMID:25121111

  5. Range sidelobe elimination in maximal sequence phase coded C.W. radars

    NASA Astrophysics Data System (ADS)

    Metaxas, D. G.; Aitchison, C. S.

    Elimination of the range sidelobe of the autocorrelation of the periodic binary maximal sequence has been achieved. A new property of the m-sequence is defined. As a result the ambiguity function of an m-sequence PSK CW radar coincides with the ambiguity function of the equivalent pulse radar as far as the range and velocity resolution are concerned. The signal to noise deterioration due to the post-correlation implementation of the new property is insignificant.

  6. Through-wall imaging and characterization of human activity using ultrawideband (UWB) random noise radar

    NASA Astrophysics Data System (ADS)

    Lai, Chieh-Ping; Narayanan, Ram M.

    2005-05-01

    Recent terrorist activities and law-enforcement situations involving hostage situations underscore the need for effective through-wall imaging. Current building interior imaging systems are based on short-pulse waveforms, which require specially designed antennas to subdue unwanted ringing. In addition, periodically transmitted pulses of energy are easily recognizable by the intelligent adversary who may employ appropriate countermeasures to confound detection. A coherent polarimetric random noise radar architecture is being developed based on UWB technology and software defined radio, which has great promise in its ability to covertly image obscured targets. The main advantages of the random noise radar lie in two aspects: first, random noise waveform has an ideal "thumbtack" ambiguity function, i.e., its down range and cross range resolution can be separately controlled, thus providing unambiguous high resolution imaging at any distance; second, random noise waveform is inherently low probability of intercept (LPI) and low probability of detection (LPD), i.e., it is immune from detection, jamming, and interference. Thus, it is an ideal candidate sensor for covert imaging of obscured regions in hostile environments. The coherency in the system can be exploited to field a fully-polarimetric system that can take advantage of polarization features in target recognition. Moving personnel can also be detected using Doppler processing. Simulation studies are used to analyze backscattered signals from the walls, and humans and other targets behind the walls. Real-time data processing shows human activity behind the wall and human target tracking. The high resolution provides excellent multipath and clutter rejection.

  7. Optical arbitrary waveform generator applicable to pulse generation and chromatic dispersion compensation of a remote UWB over fiber system.

    PubMed

    Zhou, Xin; Zheng, Xiaoping; Wen, He; Zhang, Hanyi; Zhou, Bingkun

    2011-12-12

    Optical arbitrary waveform generator (OAWG), which can generate pre-distorted ultra-wideband (UWB) pulses to tolerate the chromatic dispersion (CD) of the fiber without any other CD compensation solutions, provides a good solution for the UWB over fiber system. In our paper, we experimentally demonstrate a new OAWG scheme based on multiple incoherent continuous wave lights by double side band with suppressed carrier (DSB-SC) modulation. UWB Gaussian monocycle and doublet pulses are generated and the chromatic dispersion of 20-km, 50-km and 100-km single-mode fiber (SMF) are compensated by the OAWG system without any other CD compensation solutions. © 2011 Optical Society of America

  8. Ultrawideband monocycle pulse generation based on polarization modulator and low speed electrical NRZ signal

    NASA Astrophysics Data System (ADS)

    Sun, Guodan; Zhang, Qiufang; Wang, Quan

    2015-07-01

    A novel ultrawideband (UWB) monocycle pulse generation system by modulating a polarization modulator (PolM) with a low speed electrical nonreturn-to-zero (NRZ) signal is proposed, which significantly reduce the bandwidth requirement of the driving signal. At each bit transition of the input NRZ signal, two polarity-reversed Gaussian pulses are generated. By properly setting the delay between these two Gaussian pulses, an optical UWB monocycle pulse can be generated. Biphase modulation (BPM) can be realized by electrically switching the polarization direction at the output of PolM, if an electrically tunable arbitrary wave plate (AWP) is employed.

  9. ASIC Implementation of Highly Reliable IR-UWB Transceiver for Industrial Automation

    NASA Astrophysics Data System (ADS)

    Olonbayar, Sonom; Fischer, Gunter; Kreiser, Dan; Martynenko, Denys; Klymenko, Oleksiy; Kraemer, Rolf; Grass, Eckhard

    2016-07-01

    An in-depth treatment of impulse an radio ultra-wideband (IR-UWB) wireless system is provided reviewing theoretical background, proceeding with detailed implementation procedure, and finally giving simulation and test results. This is the first research and prototyping work to be published in the field of IR-UWB that operates in the 6-8 GHz band. The aim of this work is to implement an IR-UWB wireless system for industrial automation that is robust and reliable. To achieve this, an analogue bandwidth of 250 MHz and digital baseband processing at the clock frequency 499.2 MHz were realized in a 250 nm BiCMOS process, integrating the complete system into a single chip. Simulation and measurement results confirm that the implemented IR-UWB transceiver is operational across four frequency channels in the band 6-8 GHz each supporting three data rates 850 kb/s, 6.81 Mb/s and 27.24 Mb/s.

  10. 47 CFR 15.517 - Technical requirements for indoor UWB systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    .... 15.517 Section 15.517 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY... under the provisions of this section is limited to UWB transmitters employed solely for indoor operation... necessity to operate with a fixed indoor infrastructure, e.g., a transmitter that must be connected to the...

  11. 47 CFR 15.517 - Technical requirements for indoor UWB systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    .... 15.517 Section 15.517 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY... under the provisions of this section is limited to UWB transmitters employed solely for indoor operation... necessity to operate with a fixed indoor infrastructure, e.g., a transmitter that must be connected to the...

  12. 47 CFR 15.517 - Technical requirements for indoor UWB systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    .... 15.517 Section 15.517 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY... under the provisions of this section is limited to UWB transmitters employed solely for indoor operation... necessity to operate with a fixed indoor infrastructure, e.g., a transmitter that must be connected to the...

  13. On IEEE 802.15.6 IR-UWB receivers - simulations for DBPSK modulation.

    PubMed

    Niemelä, Ville; Hämäläinen, Matti; Iinatti, Jari

    2013-01-01

    In 2002, Federal Communications Commission (FCC) was the first in defining regulations for ultra wideband (UWB) communications followed by Europe and Japan some years later. Focusing on impulse radio (IR) UWB, in 2007 was the time for the first published standard targeting in personal area networks, released by the IEEE. The second IEEE released standard including UWB definitions is targeted for wireless body area networks (WBAN) and was published in 2012. As the wireless communications has been and will be passing through almost any levels in society, the natural step with WBAN is using it in different medical, healthcare and wellbeing applications. The arguments for these are related to the modern lifestyle, in which people have increasingly more free time and are more interested in taking care of their health and wellbeing. Another challenge is the population composition, i.e., aging in developed countries which call for new solutions and procedures, particularly from cost wise. In this paper, we are evaluating UWB receivers based on the IEEE 802.15.6 physical layer definitions and capable of detecting differentially encoded modulation. The evaluation is performed using two different WBAN channel models.

  14. Vital Sign Monitoring and Mobile Phone Usage Detection Using IR-UWB Radar for Intended Use in Car Crash Prevention.

    PubMed

    Leem, Seong Kyu; Khan, Faheem; Cho, Sung Ho

    2017-05-30

    In order to avoid car crashes, active safety systems are becoming more and more important. Many crashes are caused due to driver drowsiness or mobile phone usage. Detecting the drowsiness of the driver is very important for the safety of a car. Monitoring of vital signs such as respiration rate and heart rate is important to determine the occurrence of driver drowsiness. In this paper, robust vital signs monitoring through impulse radio ultra-wideband (IR-UWB) radar is discussed. We propose a new algorithm that can estimate the vital signs even if there is motion caused by the driving activities. We analyzed the whole fast time vital detection region and found the signals at those fast time locations that have useful information related to the vital signals. We segmented those signals into sub-signals and then constructed the desired vital signal using the correlation method. In this way, the vital signs of the driver can be monitored noninvasively, which can be used by researchers to detect the drowsiness of the driver which is related to the vital signs i.e., respiration and heart rate. In addition, texting on a mobile phone during driving may cause visual, manual or cognitive distraction of the driver. In order to reduce accidents caused by a distracted driver, we proposed an algorithm that can detect perfectly a driver's mobile phone usage even if there are various motions of the driver in the car or changes in background objects. These novel techniques, which monitor vital signs associated with drowsiness and detect phone usage before a driver makes a mistake, may be very helpful in developing techniques for preventing a car crash.

  15. Vital Sign Monitoring and Mobile Phone Usage Detection Using IR-UWB Radar for Intended Use in Car Crash Prevention

    PubMed Central

    Leem, Seong Kyu; Khan, Faheem; Cho, Sung Ho

    2017-01-01

    In order to avoid car crashes, active safety systems are becoming more and more important. Many crashes are caused due to driver drowsiness or mobile phone usage. Detecting the drowsiness of the driver is very important for the safety of a car. Monitoring of vital signs such as respiration rate and heart rate is important to determine the occurrence of driver drowsiness. In this paper, robust vital signs monitoring through impulse radio ultra-wideband (IR-UWB) radar is discussed. We propose a new algorithm that can estimate the vital signs even if there is motion caused by the driving activities. We analyzed the whole fast time vital detection region and found the signals at those fast time locations that have useful information related to the vital signals. We segmented those signals into sub-signals and then constructed the desired vital signal using the correlation method. In this way, the vital signs of the driver can be monitored noninvasively, which can be used by researchers to detect the drowsiness of the driver which is related to the vital signs i.e., respiration and heart rate. In addition, texting on a mobile phone during driving may cause visual, manual or cognitive distraction of the driver. In order to reduce accidents caused by a distracted driver, we proposed an algorithm that can detect perfectly a driver's mobile phone usage even if there are various motions of the driver in the car or changes in background objects. These novel techniques, which monitor vital signs associated with drowsiness and detect phone usage before a driver makes a mistake, may be very helpful in developing techniques for preventing a car crash. PMID:28556818

  16. Novel Dual-band Slot Antenna Design for Bluetooth and UWB Applications

    NASA Astrophysics Data System (ADS)

    Huang, Hai-Yan; Shao, Wei; Wang, Bing-Zhong; Ma, Xiao-Liang

    2014-05-01

    A novel technique to introduce an additional low frequency band to compact ultra wideband (UWB) slot antennas is proposed in this paper. To get an additional Bluetooth band, a parasitic strip is mounted on the back side of the slot edge. Because of the interaction of the strip and the slot edge, the Bluetooth band can be obtained while a notch band between the Bluetooth band and UWB band also appears. Two types of feeding, coplanar waveguide and microstrip line, are investigated. The proposed antennas are both fabricated on a low-cost FR4 substrate and have compact size (24 mm × 28 mm × 1 mm). The good agreement between measured and simulated results verifies our design.

  17. Emerging Communication Technologies (ECT) Phase 2 Report. Volume 3; Ultra Wideband (UWB) Technology

    NASA Technical Reports Server (NTRS)

    Bastin, Gary L.; Harris, William G.; Chiodini, Robert; Nelson, Richard A.; Huang, PoTien; Kruhm, David A.

    2003-01-01

    The Emerging Communication Technology (ECT) project investigated three First Mile communication technologies in support of NASA s Second Generation Reusable Launch Vehicle (2nd Gen RLV), Orbital Space Plane, Advanced Range Technology Working Group (ARTWG) and the Advanced Spaceport Technology Working Group (ASTWG). These First Mile technologies have the purpose of interconnecting mobile users with existing Range Communication infrastructures. ECT was a continuation of the Range Information System Management (RISM) task started in 2002. RISM identified the three advance communication technologies investigated under ECT. These were Wireless Ethernet (Wi-Fi), Free Space Optics (FSO), and Ultra Wideband (UWB). Due to the report s size, it has been broken into three volumes: 1) Main Report 2) Appendices 3) UWB

  18. Improving the power efficiency of SOA-based UWB over fiber systems via pulse shape randomization

    NASA Astrophysics Data System (ADS)

    Taki, H.; Azou, S.; Hamie, A.; Al Housseini, A.; Alaeddine, A.; Sharaiha, A.

    2016-09-01

    A simple pulse shape randomization scheme is considered in this paper for improving the performance of ultra wide band (UWB) communication systems using On Off Keying (OOK) or pulse position modulation (PPM) formats. The advantage of the proposed scheme, which can be either employed for impulse radio (IR) or for carrier-based systems, is first theoretically studied based on closed-form derivations of power spectral densities. Then, we investigate an application to an IR-UWB over optical fiber system, by utilizing the 4th and 5th orders of Gaussian derivatives. Our approach proves to be effective for 1 Gbps-PPM and 2 Gbps-OOK transmissions, with an advantage in terms of power efficiency for short distances. We also examine the performance for a system employing an in-line Semiconductor Optical Amplifier (SOA) with the view to achieve a reach extension, while limiting the cost and system complexity.

  19. Fabrication of CPW-Fed Fractal Antenna for UWB Applications with Omni-Directional Patterns

    PubMed Central

    Sedghi, Tohid; Jalali, Mahdi; Aribi, Tohid

    2014-01-01

    Novel and compact CPW-fed antennas are proposed comprised of a fractal patch and modified ground-plane. The ground-plane is truncated at the center and includes dielectric notches at its side to enhance the antenna's impedance bandwidth. The dimensions of the notches effectively control the upper and lower band edges of the antenna. The optimized antenna operates across 2.95–12.81 GHz for S11 ≤ −10 dB. Omnidirectional radiation pattern is achieved over the full UWB frequency range. The miniaturized antenna has a total size of 14 × 18 × 1 mm3. The characteristics of the proposed antenna are suitable for UWB wireless communication requiring low profile antennas. PMID:24672314

  20. Fabrication of CPW-fed fractal antenna for UWB applications with Omni-directional patterns.

    PubMed

    Sedghi, Tohid; Jalali, Mahdi; Aribi, Tohid

    2014-01-01

    Novel and compact CPW-fed antennas are proposed comprised of a fractal patch and modified ground-plane. The ground-plane is truncated at the center and includes dielectric notches at its side to enhance the antenna's impedance bandwidth. The dimensions of the notches effectively control the upper and lower band edges of the antenna. The optimized antenna operates across 2.95-12.81 GHz for S11 ≤ -10 dB. Omnidirectional radiation pattern is achieved over the full UWB frequency range. The miniaturized antenna has a total size of 14 × 18 × 1 mm(3). The characteristics of the proposed antenna are suitable for UWB wireless communication requiring low profile antennas.

  1. A Wireless FSCV Monitoring IC with Analog Background Subtraction and UWB Telemetry

    PubMed Central

    Dorta-Quiñones, Carlos I.; Wang, Xiao Y.; Dokania, Rajeev K.; Gailey, Alycia; Lindau, Manfred; Apsel, Alyssa B.

    2015-01-01

    A 30-μW wireless fast-scan cyclic voltammetry monitoring integrated circuit for ultra-wideband (UWB) transmission of dopamine release events in freely-behaving small animals is presented. On-chip integration of analog background subtraction and UWB telemetry yields a 32-fold increase in resolution versus standard Nyquist-rate conversion alone, near a four-fold decrease in the volume of uplink data versus single-bit, third-order, delta-sigma modulation, and more than a 20-fold reduction in transmit power versus narrowband transmission for low data rates. The 1.5-mm2 chip, which was fabricated in 65-nm CMOS technology, consists of a low-noise potentiostat frontend, a two-step analog-to-digital converter (ADC), and an impulse-radio UWB transmitter (TX). The duty-cycled frontend and ADC/UWB-TX blocks draw 4 μA and 15 μA from 3-V and 1.2-V supplies, respectively. The chip achieves an input-referred current noise of 92 pArms and an input current range of ±430 nA at a conversion rate of 10 kHz. The packaged device operates from a 3-V coin-cell battery, measures 4.7 × 1.9 cm2, weighs 4.3 g (including the battery and antenna), and can be carried by small animals. The system was validated by wirelessly recording flow-injection of dopamine with concentrations in the range of 250 nM to 1 μM with a carbon-fiber microelectrode (CFM) using 300-V/s FSCV. PMID:26057983

  2. Ultra Wideband (UWB) Synchronous Impulse Reconstruction (SIRE) Radar Upgrade Assessment Field Experiment

    DTIC Science & Technology

    2011-04-01

    transmitters, and the power available in 100 MHz bands was calculated along with a gain for an aperture antenna whose effective aperture (Ae) is 0.0071 m2...includes (a) Augmented Reality, (b) antenna array mounting structure, (c) electronic switch and electro-mechanical relay, and (d) low noise...structure with adequate height and width for mounting an array of antennas , (d) adequate space to add batteries for powering UWB SIRE radar and

  3. Implementation and Performance Analysis of Noncoherent UWB Transceiver Under LOS Residential Channel Environment

    NASA Astrophysics Data System (ADS)

    Choi, Sungsoo; Koo, Insoo; Kim, Youngsun

    This paper focuses on two things. One is to describe implementation of a Low-Rate Ultra-Wideband (LR-UWB) transceiver for low power Wireless Personal Area Network (WPAN) applications. The other is to derive the Bit Error Rate (BER) performance of the proposed system. At first, in order to implement low-power and low-complexity transceiver, we design a non-coherent On-Off-Keying(OOK) UWB system by adopting the architecture of the simplified asynchronous transmission and the edge-triggered pulse transmission, which makes the system performance independent of the shape of the transmitted waveform, robust to multipath channels. The designed non-coherent UWB transceiver architecture has an advantage of the simple realization since any mixer, high-speed correlator, and very high-sampling A/D converter are not necessary at the cost of performance degradation of about 3dB. Further, the designed non-coherent UWB transceiver is actually implemented with the wireless CANVAS prototyping testbed in short range indoor application environment such as a lecture room. The implemented prototype testbed is proven to offer the data rate of 9.6kbps and 115kbps on the conditions of Peer-to-Peer (P-to-P) in the indoor channel within the range of about 10m. At second, we analyze the bit error rate (BER) performance of this proposed system under the line-of-sight (LOS) residential channel environment. As a result, it is necessary to choose appropriate number of Window Bank(WB)s for better BER performance.

  4. Performances study of UWB monopole antennas using half-elliptic radiator conformed on elliptical surface

    NASA Astrophysics Data System (ADS)

    Djidel, S.; Bouamar, M.; Khedrouche, D.

    2016-04-01

    This paper presents a performances study of UWB monopole antenna using half-elliptic radiator conformed on elliptical surface. The proposed antenna, simulated using microwave studio computer CST and High frequency simulator structure HFSS, is designed to operate in frequency interval over 3.1 to 40 GHz. Good return loss and radiation pattern characteristics are obtained in the frequency band of interest. The proposed antenna structure is suitable for ultra-wideband applications, which is, required for many wearable electronics applications.

  5. A Wireless FSCV Monitoring IC With Analog Background Subtraction and UWB Telemetry.

    PubMed

    Dorta-Quiñones, Carlos I; Wang, Xiao Y; Dokania, Rajeev K; Gailey, Alycia; Lindau, Manfred; Apsel, Alyssa B

    2016-04-01

    A 30-μW wireless fast-scan cyclic voltammetry monitoring integrated circuit for ultra-wideband (UWB) transmission of dopamine release events in freely-behaving small animals is presented. On-chip integration of analog background subtraction and UWB telemetry yields a 32-fold increase in resolution versus standard Nyquist-rate conversion alone, near a four-fold decrease in the volume of uplink data versus single-bit, third-order, delta-sigma modulation, and more than a 20-fold reduction in transmit power versus narrowband transmission for low data rates. The 1.5- mm(2) chip, which was fabricated in 65-nm CMOS technology, consists of a low-noise potentiostat frontend, a two-step analog-to-digital converter (ADC), and an impulse-radio UWB transmitter (TX). The duty-cycled frontend and ADC/UWB-TX blocks draw 4 μA and 15 μA from 3-V and 1.2-V supplies, respectively. The chip achieves an input-referred current noise of 92 pA(rms) and an input current range of ±430 nA at a conversion rate of 10 kHz. The packaged device operates from a 3-V coin-cell battery, measures 4.7 × 1.9 cm(2), weighs 4.3 g (including the battery and antenna), and can be carried by small animals. The system was validated by wirelessly recording flow-injection of dopamine with concentrations in the range of 250 nM to 1 μM with a carbon-fiber microelectrode (CFM) using 300-V/s FSCV.

  6. A Very Compact and Low Profile UWB Planar Antenna with WLAN Band Rejection

    PubMed Central

    Syed, Avez; Aldhaheri, Rabah W.

    2016-01-01

    A low-cost coplanar waveguide fed compact ultrawideband (UWB) antenna with band rejection characteristics for wireless local area network (WLAN) is proposed. The notch band characteristic is achieved by etching half wavelength C-shaped annular ring slot in the radiating patch. By properly choosing the radius and position of the slot, the notch band can be adjusted and controlled. With an overall size of 18.7 mm × 17.6 mm, the antenna turns out to be one of the smallest UWB antennas with band-notched characteristics. It has a wide fractional bandwidth of 130% (2.9–13.7 GHz) with VSWR < 2 and rejecting IEEE 802.11a and HIPERLAN/2 frequency band of 5.1–5.9 GHz. Stable omnidirectional radiation patterns in the H plane with an average gain of 4.4 dBi are obtained. The band-notch mechanism of the proposed antenna is examined by HFSS simulator. A good agreement is found between measured and simulated results indicating that the proposed antenna is well suited for integration into portable devices for UWB applications. PMID:27088125

  7. A Very Compact and Low Profile UWB Planar Antenna with WLAN Band Rejection.

    PubMed

    Syed, Avez; Aldhaheri, Rabah W

    2016-01-01

    A low-cost coplanar waveguide fed compact ultrawideband (UWB) antenna with band rejection characteristics for wireless local area network (WLAN) is proposed. The notch band characteristic is achieved by etching half wavelength C-shaped annular ring slot in the radiating patch. By properly choosing the radius and position of the slot, the notch band can be adjusted and controlled. With an overall size of 18.7 mm × 17.6 mm, the antenna turns out to be one of the smallest UWB antennas with band-notched characteristics. It has a wide fractional bandwidth of 130% (2.9-13.7 GHz) with VSWR < 2 and rejecting IEEE 802.11a and HIPERLAN/2 frequency band of 5.1-5.9 GHz. Stable omnidirectional radiation patterns in the H plane with an average gain of 4.4 dBi are obtained. The band-notch mechanism of the proposed antenna is examined by HFSS simulator. A good agreement is found between measured and simulated results indicating that the proposed antenna is well suited for integration into portable devices for UWB applications.

  8. A Tightly-Coupled GPS/INS/UWB Cooperative Positioning Sensors System Supported by V2I Communication.

    PubMed

    Wang, Jian; Gao, Yang; Li, Zengke; Meng, Xiaolin; Hancock, Craig M

    2016-06-27

    This paper investigates a tightly-coupled Global Position System (GPS)/Ultra-Wideband (UWB)/Inertial Navigation System (INS) cooperative positioning scheme using a Robust Kalman Filter (RKF) supported by V2I communication. The scheme proposes a method that uses range measurements of UWB units transmitted among the terminals as augmentation inputs of the observations. The UWB range inputs are used to reform the GPS observation equations that consist of pseudo-range and Doppler measurements and the updated observation equation is processed in a tightly-coupled GPS/UWB/INS integrated positioning equation using an adaptive Robust Kalman Filter. The result of the trial conducted on the roof of the Nottingham Geospatial Institute (NGI) at the University of Nottingham shows that the integrated solution provides better accuracy and improves the availability of the system in GPS denied environments. RKF can eliminate the effects of gross errors. Additionally, the internal and external reliabilities of the system are enhanced when the UWB observables received from the moving terminals are involved in the positioning algorithm.

  9. A Tightly-Coupled GPS/INS/UWB Cooperative Positioning Sensors System Supported by V2I Communication

    PubMed Central

    Wang, Jian; Gao, Yang; Li, Zengke; Meng, Xiaolin; Hancock, Craig M.

    2016-01-01

    This paper investigates a tightly-coupled Global Position System (GPS)/Ultra-Wideband (UWB)/Inertial Navigation System (INS) cooperative positioning scheme using a Robust Kalman Filter (RKF) supported by V2I communication. The scheme proposes a method that uses range measurements of UWB units transmitted among the terminals as augmentation inputs of the observations. The UWB range inputs are used to reform the GPS observation equations that consist of pseudo-range and Doppler measurements and the updated observation equation is processed in a tightly-coupled GPS/UWB/INS integrated positioning equation using an adaptive Robust Kalman Filter. The result of the trial conducted on the roof of the Nottingham Geospatial Institute (NGI) at the University of Nottingham shows that the integrated solution provides better accuracy and improves the availability of the system in GPS denied environments. RKF can eliminate the effects of gross errors. Additionally, the internal and external reliabilities of the system are enhanced when the UWB observables received from the moving terminals are involved in the positioning algorithm. PMID:27355947

  10. A comprehensive study of channel estimation for WBAN-based healthcare systems: feasibility of using multiband UWB.

    PubMed

    Islam, S M Riazul; Kwak, Kyung Sup

    2012-06-01

    Wireless personal area network (WPAN) is an emerging in wireless technology for short range indoor and outdoor communication applications. A more specific category of WPAN is the wireless body area network (WBAN) used for health monitoring. On the other hand, multiband orthogonal frequency division multiplexing (MB-OFDM) ultra-wideband (UWB) comes with a number of desirable features at the physical layer for wireless communications, for example, very high data rate. One big challenge in adoption of multiband UWB in WBAN is the fact that channel estimation becomes difficult under the constraint of extremely low transmission power. Moreover, the heterogeneous environment of WBAN causes a dense multipath wireless channel. Therefore, effective channel estimation is required in the receiver of WBAN-based healthcare system that uses multiband UWB. In this paper, we first outline the MB-OFDM UWB system. Then, we present an overview of channel estimation techniques proposed/investigated for multiband UWB communications with emphasis on their strengths and weaknesses. Useful suggestions are given to overcome the weaknesses so that these methods can be particularly useful for WBAN channels. Also, we analyze the comparative performances of the techniques using computer simulation in order to find the energy-efficient channel estimation methods for WBAN-based healthcare systems.

  11. Microwave Imaging Sensor Using Compact Metamaterial UWB Antenna with a High Correlation Factor.

    PubMed

    Islam, Md Moinul; Islam, Mohammad Tariqul; Faruque, Mohammad Rashed Iqbal; Samsuzzaman, Md; Misran, Norbahiah; Arshad, Haslina

    2015-07-23

    The design of a compact metamaterial ultra-wideband (UWB) antenna with a goal towards application in microwave imaging systems for detecting unwanted cells in human tissue, such as in cases of breast cancer, heart failure and brain stroke detection is proposed. This proposed UWB antenna is made of four metamaterial unit cells, where each cell is an integration of a modified split ring resonator (SRR), capacitive loaded strip (CLS) and wire, to attain a design layout that simultaneously exhibits both a negative magnetic permeability and a negative electrical permittivity. This design results in an astonishing negative refractive index that enables amplification of the radiated power of this reported antenna, and therefore, high antenna performance. A low-cost FR4 substrate material is used to design and print this reported antenna, and has the following characteristics: thickness of 1.6 mm, relative permeability of one, relative permittivity of 4.60 and loss tangent of 0.02. The overall antenna size is 19.36 mm × 27.72 mm × 1.6 mm where the electrical dimension is 0.20 λ × 0.28 λ × 0.016 λ at the 3.05 GHz lower frequency band. Voltage Standing Wave Ratio (VSWR) measurements have illustrated that this antenna exhibits an impedance bandwidth from 3.05 GHz to more than 15 GHz for VSWR < 2 with an average gain of 4.38 dBi throughout the operating frequency band. The simulations (both HFSS and computer simulation technology (CST)) and the measurements are in high agreement. A high correlation factor and the capability of detecting tumour simulants confirm that this reported UWB antenna can be used as an imaging sensor.

  12. Microwave Imaging Sensor Using Compact Metamaterial UWB Antenna with a High Correlation Factor

    PubMed Central

    Islam, Md. Moinul; Islam, Mohammad Tariqul; Faruque, Mohammad Rashed Iqbal; Samsuzzaman, Md.; Misran, Norbahiah; Arshad, Haslina

    2015-01-01

    The design of a compact metamaterial ultra-wideband (UWB) antenna with a goal towards application in microwave imaging systems for detecting unwanted cells in human tissue, such as in cases of breast cancer, heart failure and brain stroke detection is proposed. This proposed UWB antenna is made of four metamaterial unit cells, where each cell is an integration of a modified split ring resonator (SRR), capacitive loaded strip (CLS) and wire, to attain a design layout that simultaneously exhibits both a negative magnetic permeability and a negative electrical permittivity. This design results in an astonishing negative refractive index that enables amplification of the radiated power of this reported antenna, and therefore, high antenna performance. A low-cost FR4 substrate material is used to design and print this reported antenna, and has the following characteristics: thickness of 1.6 mm, relative permeability of one, relative permittivity of 4.60 and loss tangent of 0.02. The overall antenna size is 19.36 mm × 27.72 mm × 1.6 mm where the electrical dimension is 0.20 λ × 0.28 λ × 0.016 λ at the 3.05 GHz lower frequency band. Voltage Standing Wave Ratio (VSWR) measurements have illustrated that this antenna exhibits an impedance bandwidth from 3.05 GHz to more than 15 GHz for VSWR < 2 with an average gain of 4.38 dBi throughout the operating frequency band. The simulations (both HFSS and computer simulation technology (CST)) and the measurements are in high agreement. A high correlation factor and the capability of detecting tumour simulants confirm that this reported UWB antenna can be used as an imaging sensor. PMID:28793461

  13. Next Generation Ultra-Wideband (UWB) Intrusion Detection Radar.

    DTIC Science & Technology

    2007-11-02

    Marine, Inc., Charlot- tesville, VA, which marketed the product to law enforcement agencies. The Small Business Administration, in their 5th Annual...A,= - --N,(2.3) so that the equation for determining peak power is given by: 4P 2 - 4G = P, =- watt. (2.4) Solving for the effective radiated power...term drift. A small part of the transmitter signal is sampled by a "sniffer" or probe at each element and mixed with the CW microwave reference signal. A

  14. Performances study of UWB monopole antennas using half-elliptic radiator conformed on elliptical surface

    SciTech Connect

    Djidel, S.; Bouamar, M.; Khedrouche, D.

    2016-04-21

    This paper presents a performances study of UWB monopole antenna using half-elliptic radiator conformed on elliptical surface. The proposed antenna, simulated using microwave studio computer CST and High frequency simulator structure HFSS, is designed to operate in frequency interval over 3.1 to 40 GHz. Good return loss and radiation pattern characteristics are obtained in the frequency band of interest. The proposed antenna structure is suitable for ultra-wideband applications, which is, required for many wearable electronics applications.

  15. MB-OFDM-UWB Based Wireless Multimedia Sensor Networks for Underground Coalmine: A Survey

    PubMed Central

    Han, Ruisong; Yang, Wei; You, Kaiming

    2016-01-01

    Safety production of coalmines is a task of top priority which plays an important role in guaranteeing, supporting and promoting the continuous development of the coal industry. Since traditional wireless sensor networks (WSNs) cannot fully meet the requirements of comprehensive environment monitoring of underground coalmines, wireless multimedia sensor networks (WMSNs), enabling the retrieval of multimedia information, are introduced to realize fine-grained and precise environment surveillance. In this paper, a framework for designing underground coalmine WMSNs based on Multi-Band Orthogonal Frequency-Division Multiplexing Ultra-wide Band (MB-OFDM-UWB) is presented. The selection of MB-OFDM-UWB wireless transmission solution is based on the characteristics of underground coalmines. Network structure and design challenges are analyzed first, which is the foundation for further discussion. Then, key supporting technologies and open research areas in different layers are surveyed, and we provide a detailed literature review of the state of the art strategies, algorithms and general solutions in these issues. Finally, other research issues like localization, information processing, and network management are discussed. PMID:27999258

  16. MB-OFDM-UWB Based Wireless Multimedia Sensor Networks for Underground Coalmine: A Survey.

    PubMed

    Han, Ruisong; Yang, Wei; You, Kaiming

    2016-12-16

    Safety production of coalmines is a task of top priority which plays an important role in guaranteeing, supporting and promoting the continuous development of the coal industry. Since traditional wireless sensor networks (WSNs) cannot fully meet the requirements of comprehensive environment monitoring of underground coalmines, wireless multimedia sensor networks (WMSNs), enabling the retrieval of multimedia information, are introduced to realize fine-grained and precise environment surveillance. In this paper, a framework for designing underground coalmine WMSNs based on Multi-Band Orthogonal Frequency-Division Multiplexing Ultra-wide Band (MB-OFDM-UWB) is presented. The selection of MB-OFDM-UWB wireless transmission solution is based on the characteristics of underground coalmines. Network structure and design challenges are analyzed first, which is the foundation for further discussion. Then, key supporting technologies and open research areas in different layers are surveyed, and we provide a detailed literature review of the state of the art strategies, algorithms and general solutions in these issues. Finally, other research issues like localization, information processing, and network management are discussed.

  17. UWB micro-doppler radar for human gait analysis using joint range-time-frequency representation

    NASA Astrophysics Data System (ADS)

    Wang, Yazhou; Fathy, Aly E.

    2013-05-01

    In this paper, we present a novel, standalone ultra wideband (UWB) micro-Doppler radar sensor that goes beyond simple range or micro-Doppler detection to combined range-time-Doppler frequency analysis. Moreover, it can monitor more than one human object in both line-of-sight (LOS) and through wall scenarios, thus have full human objects tracking capabilities. The unique radar design is based on narrow pulse transceiver, high speed data acquisition module, and wideband antenna array. For advanced radar post-data processing, joint range-time-frequency representation has been performed. Characteristics of human walking activity have been analyzed using the radar sensor by precisely tracking the radar object and acquiring range-time-Doppler information simultaneously. The UWB micro-Doppler radar prototype is capable of detecting Doppler frequency range from -180 Hz to +180 Hz, which allows a maximum target velocity of 9 m/s. The developed radar sensor can also be extended for many other applications, such as respiration and heartbeat detection of trapped survivors under building debris.

  18. Design of UWB monopole antenna with dual notched bands using one modified electromagnetic-bandgap structure.

    PubMed

    Liu, Hao; Xu, Ziqiang

    2013-01-01

    A modified electromagnetic-bandgap (M-EBG) structure and its application to planar monopole ultra-wideband (UWB) antenna are presented. The proposed M-EBG which comprises two strip patch and an edge-located via can perform dual notched bands. By properly designing and placing strip patch near the feedline, the proposed M-EBG not only possesses a simple structure and compact size but also exhibits good band rejection. Moreover, it is easy to tune the dual notched bands by altering the dimensions of the M-EBG. A demonstration antenna with dual band-notched characteristics is designed and fabricated to validate the proposed method. The results show that the proposed antenna can satisfy the requirements of VSWR < 2 over UWB 3.1-10.6 GHz, except for the rejected bands of the world interoperability for microwave access (WiMAX) and the wireless local area network (WLAN) at 3.5 GHz and 5.5 GHz, respectively.

  19. Planar UWB Filter with Multiple Notched Band and Stopband with Improved Rejection Level

    NASA Astrophysics Data System (ADS)

    Ghazali, Abu Nasar; Pal, Srikanta

    2015-05-01

    Analysis and realization of a microstrip-based planar ultra-wideband (UWB) filter with integrated multiple notch elimination property and simultaneously extended upper stopband is proposed. Initially, a UWB filter based on back-to-back microstrip-to-CPW technology is designed. Later, multiple spiral defected ground structures (DGS) are embedded to obtain multiple passband notches. Further, double equilateral U (DEU)-type DGS are used to improve upon the rejection level in upper stopband. The multiple passband notches are results of embedded spiral-shaped DGS (SDGS), while extended upper stopband is the outcome of suppressed higher-order spurious harmonics. The flexible dual-attenuation poles of DEU-shaped DGS suppress the stopband harmonics and widen the stopband. An approximate lumped equivalent circuit model of the proposed filter is modelled. The filter is compact and its layout measures 25.26 mm × 11.01 mm. The measured result is in good agreement with the full-wave electromagnetic (EM) simulation and circuit simulation.

  20. Toward a highly accurate ambulatory system for clinical gait analysis via UWB radios.

    PubMed

    Shaban, Heba A; Abou el-Nasr, Mohamad; Buehrer, R Michael

    2010-03-01

    In this paper, we propose and investigate a low-cost and low-complexity wireless ambulatory human locomotion tracking system that provides a high ranging accuracy (intersensor distance) suitable for the assessment of clinical gait analysis using wearable ultra wideband (UWB) transceivers. The system design and transceiver performance are presented in additive-white-gaussian noise and realistic channels, using industry accepted channel models for body area networks. The proposed system is theoretically capable of providing a ranging accuracy of 0.11 cm error at distances equivalent to interarker distances, at an 18 dB SNR in realistic on-body UWB channels. Based on real measurements, it provides the target ranging accuracy at an SNR = 20 dB. The achievable accuracy is ten times better than the accuracy reported in the literature for the intermarker-distance measurement. This makes it suitable for use in clinical gait analysis, and for the characterization and assessment of unstable mobility diseases, such as Parkinson's disease.

  1. Subbanding of temporal and spatial UWB SAR imagery of buried mines

    NASA Astrophysics Data System (ADS)

    Wong, David C.; Carin, Lawrence

    1998-09-01

    A numerical algorithm has been developed for the modeling of ultra-wideband (UWB) plane-wave scattering from a class of buried mines. In particular, the model assumes that a mine can be simulated as a body of revolution (BOR). The numerical results indicate that there are particular frequency subbands in which a given target is excited most strongly, with the subband depending strongly on the target type. Moreover, these optimal subbands are also dependent on the depression angle; therefore, the synthetic aperture radar (SAR) aperture must be limited (spatial-spectrum subbanding) so that the desired depression angle is achieved over the aperture used for imaging. These results indicate that the scattered response from particular buried mines can be highlighted by proper processing of the temporal and spatial spectrum. So motivated, we have applied subbanding to data measured by the Army Research Laboratory (ARL) UWB SAR, which collects fully polarimetric data over the 50 - 1200 MHz bandwidth. The measured data, when processed appropriately corroborate the theoretical expectations of where example anti-personnel and anti-tank mines scatter optimally. In particular, we consider the Valmara anti-personnel mine and the M20 anti-tank mine, using data collected at Yuma Proving Grounds. After validating the theory, we present frequency subbanding that will highlight one mine over another, a technique of potential application to the discrimination of targets from clutter.

  2. Design of UWB Monopole Antenna with Dual Notched Bands Using One Modified Electromagnetic-Bandgap Structure

    PubMed Central

    Xu, Ziqiang

    2013-01-01

    A modified electromagnetic-bandgap (M-EBG) structure and its application to planar monopole ultra-wideband (UWB) antenna are presented. The proposed M-EBG which comprises two strip patch and an edge-located via can perform dual notched bands. By properly designing and placing strip patch near the feedline, the proposed M-EBG not only possesses a simple structure and compact size but also exhibits good band rejection. Moreover, it is easy to tune the dual notched bands by altering the dimensions of the M-EBG. A demonstration antenna with dual band-notched characteristics is designed and fabricated to validate the proposed method. The results show that the proposed antenna can satisfy the requirements of VSWR < 2 over UWB 3.1–10.6 GHz, except for the rejected bands of the world interoperability for microwave access (WiMAX) and the wireless local area network (WLAN) at 3.5 GHz and 5.5 GHz, respectively. PMID:24170984

  3. Low-power wide-locking-range injection-locked frequency divider for OFDM UWB systems

    NASA Astrophysics Data System (ADS)

    Jiangwei, Yin; Ning, Li; Renliang, Zheng; Wei, Li; Junyan, Ren

    2009-05-01

    This paper describes a divide-by-two injection-locked frequency divider (ILFD) for frequency synthesizers as used in multiband orthogonal frequency division multiplexing (OFDM) ultra-wideband (UWB) systems. By means of dual-injection technique and other conventional tuning techniques, such as DCCA and varactor tuning, the divider demonstrates a wide locking range while consuming much less power. The chip was fabricated in the Jazz 0.18 μm RF CMOS process. The measurement results show that the divider achieves a locking range of 4.85 GHz (6.23 to 11.08 GHz) at an input power of 8 dBm. The core circuit without the test buffer consumes only 3.7 mA from a 1.8 V power supply and has a die area of 0.38 × 0.28 mm2. The wide locking range combined with low power consumption makes the ILFD suitable for its application in UWB systems.

  4. A high linearity dual-band mixer for IMT-A and UWB systems

    NASA Astrophysics Data System (ADS)

    Xusheng, Tang; Xiaoyu, Wang; Jiang, Yang; Xin, Tang; Fengyi, Huang

    2014-11-01

    The design and analysis of a reconfigurable dual-band down-conversion mixer for IMT-advanced (3.4-3.6 GHz) and UWB (4.2-4.8 GHz) applications are presented. Based on a folded double-balanced Gilbert cell, which is well known for its low voltage, simplicity and well balanced performance, the mixer adopts a capacitive cross-coupling technique for input matching and performance improvement. Switched capacitors and resistors are added to shift the working bands. Fabricated in a TSMC 0.13 μm process, the test results show flat conversion gains from 9.6 to 10.3 dB on the IMT-A band and from 9.7 to 10.4 dB on the UWB band, with a noise figure of about 15 dB on both bands. The input third-order intercept points (IIP3) are about 7.3 dBm on both of the frequency bands. The whole chip consumes 11 mW under 1.2 V supply and the total area of the layout is 0.76 × 0.65 mm2.

  5. Information retrieval and cross-correlation function analysis of random noise radar signal through dispersive media

    NASA Astrophysics Data System (ADS)

    Alejos, Ana Vazques; Dawood, Muhammad

    2012-06-01

    In this contribution we examine the propagation of an ultrawideband (UWB) random noise signal through dispersive media such as soil, vegetation, and water, using Fourier-based analysis. For such media, the propagated signal undergoes medium-specific impairments which degrade the received signal in a different way than the non-dispersive propagation media. Theoretically, larger penetration depths into a dispersive medium can be achieved by identifying and detecting the precursors, thereby offering significantly better signal-to-noise ratio and enhanced imaging. For a random noise signal, well defined precursors in term of peak-amplitude don't occur. The phenomenon must therefore be studied in terms of energy evolution. Additionally, the distortion undergone by the UWB random noise signal through a dispersive medium can introduce frequency-dependent uncertainty or noise in the received signal. This leads to larger degradation of the cross-correlation function (CCF), mainly in terms of sidelobe levels and main peak deformation, and consequently making the information retrieval difficult. We would further analyze one method to restore the shape and carrier frequency of the input UWB random noise signal, thereby, improving the CCF estimation.

  6. A magnetometer-free indoor human localization based on loosely coupled IMU/UWB fusion.

    PubMed

    Zihajehzadeh, Shaghayegh; Yoon, Paul K; Park, Edward J

    2015-01-01

    The magnetic distortions in indoor environment affects the accuracy of yaw angle estimation using magnetometer. Thus, the accuracy of indoor localization based on inertial-magnetic sensors will be affected as well. To address this issue, this paper proposes a magnetometer-free solution for indoor human localization and yaw angle estimation. The proposed algorithm fuses a wearable inertial sensor consisting of MEMS-based accelerometer and gyroscope with a portable ultra-wideband (UWB) localization system in a cascaded two-step filter consisting of a tilt Kalman filter and a localization Kalman filter. By benchmarking against an optical motion capture system, the experimental results show that the proposed algorithm can accurately track position and velocity as well as the yaw angle without using magnetometer.

  7. A novel chaos-based UWB sensor for enhancing homeland security

    NASA Astrophysics Data System (ADS)

    Venkatasubramanian, Vijayaraghavan; Leung, Henry

    2005-05-01

    In this paper, we propose a novel chaos based ultra-wideband (UWB) sensor to enhance homeland security applications. The proposed chaos based modulation has a good resolution when used for wall penetrating applications. The receiver exploits the deterministic nature of chaos to cancel room reverberations avoiding complex synchronization procedure. Numerical electromagnetic (EM) simulations using finite difference time domain (FDTD) method are performed to illustrate the imaging performance of the proposed radar under real life surveillance situations with hidden and moving targets. The simulations are also employed to analyze the extent of penetrating ability of the proposed scheme for different structures. The effect of various structures and thickness on the detection performance are also commented upon.

  8. A Compact 5.5 GHz Band-Rejected UWB Antenna Using Complementary Split Ring Resonators

    PubMed Central

    Islam, M. M.; Faruque, M. R. I.; Islam, M. T.

    2014-01-01

    A band-removal property employing microwave frequencies using complementary split ring resonators (CSRRs) is applied to design a compact UWB antenna wishing for the rejection of some frequency band, which is meanwhile exercised by the existing wireless applications. The reported antenna comprises optimization of a circular radiating patch, in which slotted complementary SRRs are implanted. It is printed on low dielectric FR4 substrate material fed by a partial ground plane and a microstrip line. Validated results exhibit that the reported antenna shows a wide bandwidth covering from 3.45 to more than 12 GHz, with a compact dimension of 22 × 26 mm2, and VSWR < 2, observing band elimination of 5.5 GHz WLAN band. PMID:24971379

  9. A Frequency Offset Estimation and Compensation Scheme for MB-OFDM UWB Modem

    NASA Astrophysics Data System (ADS)

    Kim, Do-Hoon; Kang, Kyu-Min; Lee, Chungyong

    We present a carrier and sampling frequency offset estimation and compensation scheme for a multi-band orthogonal frequency division multiplexing (MB-OFDM) ultra-wideband (UWB) modem. We first perform initial carrier frequency offset (CFO) estimation and compensation during the preamble period, and then conduct the estimation and compensation of the residual CFO and sampling frequency offset (SFO) during the payload period. The proposed design scheme reduces the logic gate count of the frequency offset compensation block by about 10%, while it gives almost the same performance at the packet error rate (PER) of 10-4 in the CM1 channel. The frequency offset estimation and compensation block is implemented using 90nm CMOS technology and tested.

  10. Measurement of the transient shielding effectiveness of enclosures using UWB pulses inside an open TEM waveguide

    NASA Astrophysics Data System (ADS)

    Herlemann, H.; Koch, M.

    2007-06-01

    Recently, new definitions of shielding effectiveness (SE) for high-frequency and transient electromagnetic fields were introduced by Klinkenbusch (2005). Numerical results were shown for closed as well as for non closed cylindrical shields. In the present work, a measurement procedure is introduced using ultra wideband (UWB) electromagnetic field pulses. The procedure provides a quick way to determine the transient shielding effectiveness of an enclosure without performing time consuming frequency domain measurements. For demonstration, a cylindrical enclosure made of conductive textile is examined. The field pulses are generated inside an open TEM-waveguide. From the measurement of the transient electric and magnetic fields with and without the shield in place, the electric and magnetic shielding effectiveness of the shielding material as well as the transient shielding effectiveness of the enclosure are derived.

  11. Multiple-Antenna Receiving and Frequency Domain Equalization in Transmitted-Reference UWB Systems

    NASA Astrophysics Data System (ADS)

    Liao, Xuewen; Zhu, Shihua; Zeng, Erlin

    A multiple-antenna receiving and combining scheme is proposed for high-data-rate transmitted-reference (TR) Ultra-Wideband (UWB) systems. The nonlinearity of the inter-symbol interference (IST) model is alleviated via simple antenna combining. Under the simplified ISI model, frequency domain equalization (FDE) is adopted and greatly reduces the complexity of the equalizer. A simple estimation algorithm for the simplified ISI model is presented. Simulation results demonstrate that compared to the single receive antenna scheme, the proposed method can obtain a significant diversity gain and eliminate the BER floor effect. Moreover, compared to the complex second-order time domain equalizer, FDE showed better performance robustness in the case of imperfect model estimation.

  12. Design of Compact Flower Shape Dual Notched-Band Monopole Antenna for Extended UWB Wireless Applications

    NASA Astrophysics Data System (ADS)

    Sharma, Manish; Awasthi, Y. K.; Singh, Himanshu; Kumar, Raj; Kumari, Sarita

    2016-11-01

    In this letter, a compact monopole antenna for ultra wideband (UWB) applications is proposed with small size of 18×20=360 mm2. Antenna consist of a flower shape radiating patch with a pair of C-shaped slots which offer two notch bands for WiMAX (3.04-3.68 GHz) & WLAN (4.73-5.76 GHz) and two rectangular shaped slots in the ground plane which provides a wide measured usable fractional extended bandwidth of 163 % (2.83-14.0 GHz) with improved VSWR. Moreover, it is also convenient for other wireless application as close range radar, 8-12 GHz in X-band. Measured radiation patterns exhibits nearly omnidirectional in H-plane and dipole like pattern in E-plane across the bandwidth and furthermore exhibits good time domain performance.

  13. Measurement of knee flexion/extension angle using wearable UWB radios.

    PubMed

    Qi, Yongbin; Soh, Cheong Boon; Gunawan, Erry; Low, Kay-Soon; Maskooki, Arash

    2013-01-01

    This paper proposes a wearable system using UWB transceivers to measure the knee flexion/extension angle parameter, who is known to be of clinical importance. First, a pair of very small and light antennas is placed on the adjacent segments of knee joint. Then, the range data between these two antennas is acquired using Time of Arrival (TOA) estimator. We further use the measured distance to compute the flexion/extension angle using the law of cosines. The performance of the method was compared with a flexible goniometer by simultaneously measuring knee flexion-extension angle. The experimental results show that the system has reasonable performance and has sufficient accuracy for clinical applications.

  14. A compact 5.5 GHz band-rejected UWB antenna using complementary split ring resonators.

    PubMed

    Islam, M M; Faruque, M R I; Islam, M T

    2014-01-01

    A band-removal property employing microwave frequencies using complementary split ring resonators (CSRRs) is applied to design a compact UWB antenna wishing for the rejection of some frequency band, which is meanwhile exercised by the existing wireless applications. The reported antenna comprises optimization of a circular radiating patch, in which slotted complementary SRRs are implanted. It is printed on low dielectric FR4 substrate material fed by a partial ground plane and a microstrip line. Validated results exhibit that the reported antenna shows a wide bandwidth covering from 3.45 to more than 12 GHz, with a compact dimension of 22 × 26 mm(2), and VSWR < 2, observing band elimination of 5.5 GHz WLAN band.

  15. Scattering, resonance, creeping wave, traveling wave and all that: UWB measurements of various targets

    NASA Astrophysics Data System (ADS)

    Madonna, R. G.; Scheno, P. J.; Vilardi, G. H.; Hom, C.; Scannepieco, J.

    1993-01-01

    Ultra Wide Band (UWB) impulse radar has the potential to perform target identification. In order to realize this potential, target signatures must be measured and understood from the stand point of electromagnetic scattering. This paper discusses measurements of target 'echoes' using an impulse UWB system. We first examine the interaction of the transmitted pulse with conductive plates. At small incidence angles, we observe both specular scattering and a late time resonance. At large incidence angles, interactions with the leading edge and traveling waves are observed. In order to enhance the traveling wave interaction, we fabricated and test 'bullets' which are 5 foot long, 6 inch wide aluminum strips whose front ends are tapered to a point. The bullets are oriented approximately 20 deg to the incident wave. The returns from the bullets are due almost completely to traveling wave. We then look at data gather from a sphere. One clearly sees the specular return followed by the creeping wave. Resonance is observed at late times. We also have examined a dipole, which has a very large cross section at its resonance frequency. The dipole clearly exhibits ringing at ist fundamental fequency. We have fabricated and are in the process of measuring a resonance cavity. The cavity consists of a 27 inch diameter sphere with a 20 deg cap removed and a conducting cone (13.5 inches high) inserted into the sphere. We are observing resonance, and scattering from the cone. We will have more details to report at a later time as the measurements are in progress.

  16. Analysis of hyperbolic signatures from small discontinuities using an UWB ground-coupled radar: FDTD simulations and field experiments

    NASA Astrophysics Data System (ADS)

    Sagnard, Florence; Tebchrany, Elias; Baltazart, Vincent

    2013-04-01

    Ground penetrating radar (GPR) is a well-known non-destructive technique based on electromagnetic wave propagation that is able to detect by reflection or scattering of waves dielectric discontinuities in the underground. Our application is mainly concerned with civil engineering to perform supervision, inventory, and soil characterization. Because the air-coupled radar suffers from a significant reflection at the ground interface that reduces energy transfer of electromagnetic radiation in the sub-surface and penetration depth, we have developed an ultra-wide band (UWB) ground-coupled radar made of a pair of partially shielded compact planar bowtie slot antennas. As the antenna dimension (36*23 cm2) is close to the A4 sheet size, the maturity of the microstrip technology has allowed to design a particular geometry on the FR4 substrate (h=1.5 mm) which is able to operate at frequencies from 460 MHz to beyond 4 GHz in air. Contrary to a commercial GPR where details on antenna design are not available, it appears here possible to know and control the radiation characteristics and develop full-wave FDTD modeling that can represent field experiments for comparisons and analyses. The objective of this work is to improve, by means of a parametric study, the knowledge of physical phenomena involved in dielectric polarization when waves interact with buried discontinuities and particularly cracks, pipes, delaminations that can be distinguished by their shape, size, dielectric contrast with the surrounding medium, orientation relative to the electric field… Thus, we have first characterized by FDTD modeling and field measurements in a wet sand the radar link in two perpendicular polarizations (parallel and mirror) in the presence of a common soil (epsilon'=5.5, sigma=0.01 S/m) considering variable offsets. Afterwards, we have studied and analyzed the hyperbola signatures generated by the presence of buried canonical objects (pipes, strips) with several dielectric

  17. Integrable high order UWB pulse photonic generator based on cross phase modulation in a SOA-MZI.

    PubMed

    Moreno, Vanessa; Rius, Manuel; Mora, José; Muriel, Miguel A; Capmany, José

    2013-09-23

    We propose and experimentally demonstrate a potentially integrable optical scheme to generate high order UWB pulses. The technique is based on exploiting the cross phase modulation generated in an InGaAsP Mach-Zehnder interferometer containing integrated semiconductor optical amplifiers, and is also adaptable to different pulse modulation formats through an optical processing unit which allows to control of the amplitude, polarity and time delay of the generated taps.

  18. A 10.6mm3 Fully-Integrated, Wireless Sensor Node with 8GHz UWB Transmitter

    PubMed Central

    Kim, Hyeongseok; Kim, Gyouho; Lee, Yoonmyung; Foo, Zhiyoong; Sylvester, Dennis; Blaauw, David; Wentzloff, David

    2015-01-01

    This paper presents a complete, autonomous, wireless temperature sensor, fully encapsulated in a 10.6mm3 volume. The sensor includes solar energy harvesting with an integrated 2 μAh battery, optical receiver for programming, microcontroller and memory, 8GHz UWB transmitter, and miniaturized custom antennas with a wireless range of 7 meters. Full, stand-alone operation was demonstrated for the first time for a system of this size and functionality. PMID:26855848

  19. Compact self-grounded Bow-Tie antenna design for an UWB phased-array hyperthermia applicator.

    PubMed

    Takook, Pegah; Persson, Mikael; Gellermann, Johanna; Trefná, Hana Dobšíček

    2017-01-08

    Using UWB hyperthermia systems has the potential to improve the heat delivery to deep seated tumours. In this paper, we present a novel self-grounded Bow-Tie antenna design which is to serve as the basis element in a phased-array applicator. The UWB operation in the frequency range of 0.43-1 GHz is achieved by immersing the antenna in a water bolus. The radiation characteristics are improved by appropriate shaping the water bolus and by inclusion of dielectric layers on the top of the radiating arms of the antenna. In order to find the most appropriate design, we use a combination of performance indicators representing the most important attributes of the antenna. These are the UWB impedance matching, the transmission capability and the effective field size. The antenna was constructed and experimentally validated on muscle-like phantom. The measured reflection and transmission coefficients as well as radiation characteristics are in excellent agreement with the simulated results. MR image acquisitions with antenna located inside MR bore indicate a negligible distortion of the images by the antenna itself, which indicates MR compatibility.

  20. Path loss variation of on-body UWB channel in the frequency bands of IEEE 802.15.6 standard

    PubMed Central

    Sarma, Kanak C.; Mahanta, Anil

    2016-01-01

    The wireless body area network (WBAN) has gaining tremendous attention among researchers and academicians for its envisioned applications in healthcare service. Ultra wideband (UWB) radio technology is considered as excellent air interface for communication among body area network devices. Characterisation and modelling of channel parameters are utmost prerequisite for the development of reliable communication system. The path loss of on-body UWB channel for each frequency band defined in IEEE 802.15.6 standard is experimentally determined. The parameters of path loss model are statistically determined by analysing measurement data. Both the line-of-sight and non-line-of-sight channel conditions are considered in the measurement. Variations of parameter values with the size of human body are analysed along with the variation of parameter values with the surrounding environments. It is observed that the parameters of the path loss model vary with the frequency band as well as with the body size and surrounding environment. The derived parameter values are specific to the particular frequency bands of IEEE 802.15.6 standard, which will be useful for the development of efficient UWB WBAN system. PMID:27382482

  1. Through-the-Wall Localization of a Moving Target by Two Independent Ultra Wideband (UWB) Radar Systems

    PubMed Central

    Kocur, Dušan; Švecová, Mária; Rovňáková, Jana

    2013-01-01

    In the case of through-the-wall localization of moving targets by ultra wideband (UWB) radars, there are applications in which handheld sensors equipped only with one transmitting and two receiving antennas are applied. Sometimes, the radar using such a small antenna array is not able to localize the target with the required accuracy. With a view to improve through-the-wall target localization, cooperative positioning based on a fusion of data retrieved from two independent radar systems can be used. In this paper, the novel method of the cooperative localization referred to as joining intersections of the ellipses is introduced. This method is based on a geometrical interpretation of target localization where the target position is estimated using a properly created cluster of the ellipse intersections representing potential positions of the target. The performance of the proposed method is compared with the direct calculation method and two alternative methods of cooperative localization using data obtained by measurements with the M-sequence UWB radars. The direct calculation method is applied for the target localization by particular radar systems. As alternative methods of cooperative localization, the arithmetic average of the target coordinates estimated by two single independent UWB radars and the Taylor series method is considered. PMID:24021968

  2. Path loss variation of on-body UWB channel in the frequency bands of IEEE 802.15.6 standard.

    PubMed

    Goswami, Dayananda; Sarma, Kanak C; Mahanta, Anil

    2016-06-01

    The wireless body area network (WBAN) has gaining tremendous attention among researchers and academicians for its envisioned applications in healthcare service. Ultra wideband (UWB) radio technology is considered as excellent air interface for communication among body area network devices. Characterisation and modelling of channel parameters are utmost prerequisite for the development of reliable communication system. The path loss of on-body UWB channel for each frequency band defined in IEEE 802.15.6 standard is experimentally determined. The parameters of path loss model are statistically determined by analysing measurement data. Both the line-of-sight and non-line-of-sight channel conditions are considered in the measurement. Variations of parameter values with the size of human body are analysed along with the variation of parameter values with the surrounding environments. It is observed that the parameters of the path loss model vary with the frequency band as well as with the body size and surrounding environment. The derived parameter values are specific to the particular frequency bands of IEEE 802.15.6 standard, which will be useful for the development of efficient UWB WBAN system.

  3. Through-the-wall localization of a moving target by two independent ultra wideband (UWB) radar systems.

    PubMed

    Kocur, Dušan; Svecová, Mária; Rovňáková, Jana

    2013-09-09

    In the case of through-the-wall localization of moving targets by ultra wideband (UWB) radars, there are applications in which handheld sensors equipped only with one transmitting and two receiving antennas are applied. Sometimes, the radar using such a small antenna array is not able to localize the target with the required accuracy. With a view to improve through-the-wall target localization, cooperative positioning based on a fusion of data retrieved from two independent radar systems can be used. In this paper, the novel method of the cooperative localization referred to as joining intersections of the ellipses is introduced. This method is based on a geometrical interpretation of target localization where the target position is estimated using a properly created cluster of the ellipse intersections representing potential positions of the target. The performance of the proposed method is compared with the direct calculation method and two alternative methods of cooperative localization using data obtained by measurements with the M-sequence UWB radars. The direct calculation method is applied for the target localization by particular radar systems. As alternative methods of cooperative localization, the arithmetic average of the target coordinates estimated by two single independent UWB radars and the Taylor series method is considered.

  4. Performance evaluation on FPGA-implemented UWB-IR receiver for in-body to out-of-body communication systems.

    PubMed

    Shimizu, Yuto; Anzai, Daisuke; Jianqing Wang

    2014-01-01

    In order to design an optimized transceiver structure of ultra wideband (UWB) transmission in in-body to out-of-body communications, it is necessary to make the transceiver structure be easily adjustable in order to realize a good communication performance in an experimental environment. For this purpose, we first implement our develop UWB-impulse radio (IR) receiver structure for the in-body to out-of-body communication in a field programmable gate array (FPGA) board, and evaluate the fundamental communication performance of the FPGA-implemented UWB-IR receiver by a biological-equivalent liquid phantom experiment. The FPGA configuration results indicate that our FPGA realization of the UWB-IR receiver has accomplished good communication performance with few FPGA slices. Moreover, the evaluation results in the liquid phantom experiment show that the FPGA-implemented UWB-IR receiver can achieve a bit error rate (BER) of 10(-3) up to a communication distance of 70 mm with ensuring a high data rate of 2 Mbps.

  5. Efficient Management of Multiple Piconets in an MC-CDMA-Based UWB System

    NASA Astrophysics Data System (ADS)

    Gong, Peng; Xue, Peng; Piao, Cheng Jie; Kim, Duk Kyung

    With multiple overlapped piconets, the IEEE 802.15.3 Medium Access Control (MAC) protocol uses a Parent/Child (P/C) or Parent/Neighbor (P/N) configuration to avoid inter-piconet interference. However, the throughput of a P/N or P/C configuration cannot exceed that of a single piconet. In the present paper we propose an efficient means of managing multiple piconets to cooperate with a Multi-Carrier Code Division Multiple Access (MC-CDMA) based UWB system. The proposed management approach uses an Intermediate Device (IDEV) to connect Piconet Coordinators (PNCs). A senior PNC adaptively arranges two simultaneous data transmission links with the proposed spreading matrices in each Channel Time Allocation (CTA) instead of a P/C or P/N configuration, which supports only a single link in each CTA. Simulation results demonstrate the proposed scheme can achieve a higher throughput with an acceptable compromise of link success probability in multiple overlapped piconets.

  6. UWB Band-notched Adjustable Antenna Using Concentric Split-ring Slots Structure

    NASA Astrophysics Data System (ADS)

    Yin, Y.; Hong, J. S.

    2014-09-01

    In this paper, a kind of concentric split-ring slots structure is utilized to design a novel triple-band-notched UWB antenna. Firstly, a concentric split-ring slots structure that has a higher VSWR than that of a single slot at notch frequency is presented. What's more, the structure is very simple and feasible to obtain notched-band at different frequency by adjustment of the length of slot. Secondly, a triple-band-notched antenna, whose notched bands are at 3.52-3.81 GHz for WiMAX and 5.03-5.42 GHz and 5.73-56.17 GHz for WLAN, is designed by using this structure. At last, a compact size of 24 × 30 mm2 of the proposed antenna has been fabricated and measured and it is shown that the proposed antenna has a broadband matched impedance (3.05-14 GHz, VSWR < 2), relatively stable gain and good omnidirectional radiation patterns at low bands.

  7. A multiuser detector based on artificial bee colony algorithm for DS-UWB systems.

    PubMed

    Yin, Zhendong; Liu, Xiaohui; Wu, Zhilu

    2013-01-01

    Artificial Bee Colony (ABC) algorithm is an optimization algorithm based on the intelligent behavior of honey bee swarm. The ABC algorithm was developed to solve optimizing numerical problems and revealed premising results in processing time and solution quality. In ABC, a colony of artificial bees search for rich artificial food sources; the optimizing numerical problems are converted to the problem of finding the best parameter which minimizes an objective function. Then, the artificial bees randomly discover a population of initial solutions and then iteratively improve them by employing the behavior: moving towards better solutions by means of a neighbor search mechanism while abandoning poor solutions. In this paper, an efficient multiuser detector based on a suboptimal code mapping multiuser detector and artificial bee colony algorithm (SCM-ABC-MUD) is proposed and implemented in direct-sequence ultra-wideband (DS-UWB) systems under the additive white Gaussian noise (AWGN) channel. The simulation results demonstrate that the BER and the near-far effect resistance performances of this proposed algorithm are quite close to those of the optimum multiuser detector (OMD) while its computational complexity is much lower than that of OMD. Furthermore, the BER performance of SCM-ABC-MUD is not sensitive to the number of active users and can obtain a large system capacity.

  8. Time-lapse imaging of human heart motion with switched array UWB radar.

    PubMed

    Brovoll, Sverre; Berger, Tor; Paichard, Yoann; Aardal, Øyvind; Lande, Tor Sverre; Hamran, Svein-Erik

    2014-10-01

    Radar systems for detection of human heartbeats have mostly been single-channel systems with limited spatial resolution. In this paper, a radar system for ultra-wideband (UWB) imaging of the human heart is presented. To make the radar waves penetrate the human tissue the antenna is placed very close to the body. The antenna is an array with eight elements, and an antenna switch system connects the radar to the individual elements in sequence to form an image. Successive images are used to build up time-lapse movies of the beating heart. Measurements on a human test subject are presented and the heart motion is estimated at different locations inside the body. The movies show rhythmic motion consistent with the beating heart, and the location and shape of the reflections correspond well with the expected response form the heart wall. The spatial dependent heart motion is compared to ECG recordings, and it is confirmed that heartbeat modulations are seen in the radar data. This work shows that radar imaging of the human heart may provide valuable information on the mechanical movement of the heart.

  9. Flexible, Polarization-Diverse UWB Antennas for Implantable Neural Recording Systems.

    PubMed

    Bahrami, Hadi; Mirbozorgi, S Abdollah; Ameli, Reza; Rusch, Leslie A; Gosselin, Benoit

    2016-02-01

    Implanted antennas for implant-to-air data communications must be composed of material compatible with biological tissues. We design single and dual-polarization antennas for wireless ultra-wideband neural recording systems using an inhomogeneous multi-layer model of the human head. Antennas made from flexible materials are more easily adapted to implantation; we investigate both flexible and rigid materials and examine performance trade-offs. The proposed antennas are designed to operate in a frequency range of 2-11 GHz (having S11 below -10 dB) covering both the 2.45 GHz (ISM) band and the 3.1-10.6 GHz UWB band. Measurements confirm simulation results showing flexible antennas have little performance degradation due to bending effects (in terms of impedance matching). Our miniaturized flexible antennas are 12 mm×12 mm and 10 mm×9 mm for single- and dual-polarizations, respectively. Finally, a comparison is made of four implantable antennas covering the 2-11 GHz range: 1) rigid, single polarization, 2) rigid, dual polarization, 3) flexible, single polarization and 4) flexible, dual polarization. In all cases a rigid antenna is used outside the body, with an appropriate polarization. Several advantages were confirmed for dual polarization antennas: 1) smaller size, 2) lower sensitivity to angular misalignments, and 3) higher fidelity.

  10. A Multiuser Detector Based on Artificial Bee Colony Algorithm for DS-UWB Systems

    PubMed Central

    Liu, Xiaohui

    2013-01-01

    Artificial Bee Colony (ABC) algorithm is an optimization algorithm based on the intelligent behavior of honey bee swarm. The ABC algorithm was developed to solve optimizing numerical problems and revealed premising results in processing time and solution quality. In ABC, a colony of artificial bees search for rich artificial food sources; the optimizing numerical problems are converted to the problem of finding the best parameter which minimizes an objective function. Then, the artificial bees randomly discover a population of initial solutions and then iteratively improve them by employing the behavior: moving towards better solutions by means of a neighbor search mechanism while abandoning poor solutions. In this paper, an efficient multiuser detector based on a suboptimal code mapping multiuser detector and artificial bee colony algorithm (SCM-ABC-MUD) is proposed and implemented in direct-sequence ultra-wideband (DS-UWB) systems under the additive white Gaussian noise (AWGN) channel. The simulation results demonstrate that the BER and the near-far effect resistance performances of this proposed algorithm are quite close to those of the optimum multiuser detector (OMD) while its computational complexity is much lower than that of OMD. Furthermore, the BER performance of SCM-ABC-MUD is not sensitive to the number of active users and can obtain a large system capacity. PMID:23983638

  11. SEMICONDUCTOR INTEGRATED CIRCUITS: A low-spurious fast-hopping MB-OFDM UWB synthesizer

    NASA Astrophysics Data System (ADS)

    Danfeng, Chen; Wei, Li; Ning, Li; Junyan, Ren

    2010-06-01

    A frequency synthesizer for the ultra-wide band (UWB) group #1 is proposed. The synthesizer uses a phase-locked loop (PLL) and single-sideband (SSB) mixers to generate the three center frequencies of the first band group by mixing 4224 MHz with ±264 MHz and 792 MHz, respectively. A novel multi-QSSB mixer is designed to combine the function of frequency selection and frequency conversion for low power and high linearity. The synthesizer is fabricated in Jazz 0.18-μm RF CMOS technology. The measured reference spur is as low as -69 dBc and the maximum spur is the LO leakage of -32 dBc. A low phase noise of -110 dBc/Hz @ 1 MHz offset and an integrated phase noise of 1.86° are achieved. The hopping time between different bands is less than 1.8 ns. The synthesizer consumes 30 mA from a 1.8 V supply.

  12. Hybrid ARQ Error-Controlling Scheme for Robust and Efficient Transmission of UWB Body Area Networks

    NASA Astrophysics Data System (ADS)

    Suzuki, Haruka; Hernandez, Marco; Kohno, Ryuji

    This paper presents hybrid type-II automatic repeat request (H-ARQ) for wireless wearable body area networks (BANs) based on ultra wideband (UWB) technology. The proposed model is based on three schemes, namely, high rate optimized rate compatible punctured convolutional codes (HRO-RCPC), Reed Solomon (RS) invertible codes and their concatenation. Forward error correction (FEC) coding is combined with simple cyclic redundancy check (CRC) error detection. The performance is investigated for two channels: CM3 (on-body to on-body) and CM4 (on-body to a gateway) scenarios of the IEEE802.15.6 BAN channel models for BANs. It is shown that the improvement in performance in terms of throughput and error protection robustness is very significant. Thus, the proposed H-ARQ schemes can be employed and optimized to suit medical and non-medical applications. In particular we propose the use of FEC coding for non-medical applications as those require less stringent quality of service (QoS), while the incremental redundancy and ARQ configuration is utilized only for medical applications. Thus, higher QoS is guaranteed for medical application of BANs while allowing coexistence with non-medical applications.

  13. Meander-line-based inhomogeneous anisotropic artificial material for gain enhancement of UWB Vivaldi antenna

    NASA Astrophysics Data System (ADS)

    Pandey, Gaurav Kumar; Singh, Hari Shankar; Meshram, Manoj Kumar

    2016-02-01

    An inhomogeneous anisotropic (IA) artificial material (AM) is proposed having epsilon-near-zero (ENZ) characteristics and effective refractive index >1, simultaneously, in the same direction. Further, the proposed IA-AM is utilized for the gain enhancement of Vivaldi antenna for ultra-wideband (UWB) applications. The IA-AM consists of two types of compact meandered line-based anisotropic artificial material with ENZ characteristics in two adjacent narrow bands of 5.5-8.5 and 8-11.5 GHz. However, the non-resonant behavior of the artificial material in other direction appears with high refractive index property in broadband region. The combination of both the unit cells with broadband ENZ and high refractive index property is used to improve the gain of the Vivaldi antenna in broadband. The proposed IA-AM-loaded Vivaldi antenna exhibits a gain enhancement of up to 2 dBi compared to the original antenna in the operating frequency band of 3.1-12 GHz with | S 11| < -10 dB. The proposed antenna shows nearly stable unidirectional radiation patterns with high directivity and nearly flat group delay.

  14. Covert communications using random noise signals: effects of atmospheric propagation nulls and rain

    NASA Astrophysics Data System (ADS)

    Mohan, Karen M.; Narayanan, Ram M.

    2005-06-01

    In military communications, there exist numerous potential threats to message security. Ultra-wideband (UWB) signals provide secure communications because they cannot, in general, be detected using conventional receivers and they can be made relatively immune from jamming. The security of an UWB signal can be further improved by mixing it with random noise. By using a random noise signal, the user can conceal the message signal within the noise waveform and thwart detection by hostile forces. This paper describes a novel spread spectrum technique that can be used for secure and covert communications. The technique is based on the use of heterodyne correlation techniques to inject coherence in a random noise signal. The modulated signal to be transmitted containing the coherent carrier is mixed with a sample of an ultra-wideband (UWB) random noise signal. The frequency range of the UWB noise signal is appropriately chosen so that the lower sideband of the mixing process falls over the same frequency range. Both the frequency-converted noise-like signal and the original random noise signal are simultaneously transmitted on orthogonally polarized channels through a dual-polarized transmitting antenna. The receiver consists of a similar dual-polarized antenna that simultaneously receives the two orthogonally polarized transmitted signals, amplifies each in a minimum phase limiting amplifier, and mixes these signals in a double sideband upconverter. The upper sideband of the mixing process recovers the modulated signal, which can then be demodulated. The advantage of this technique lies in the relative immunity of the random noise-like unpolarized transmit signal from detection and jamming. Since the transmitted signal "appears" totally unpolarized and noise-like, linearly polarized receivers are unable to identify, decode, or otherwise extract useful information from the signal. The system is immune from interference caused by high power linearly polarized signal

  15. 0.18 um 3.1-10.6 GHz CMOS UWB LNA with 25±1dB gain

    NASA Astrophysics Data System (ADS)

    Shamsadini, Shila; Kashani, Farokh Hojat; Bathaei, Neda

    2011-05-01

    A 3.1-10.6 GHz ultra-wideband low noise-amplifier (UWB LNA) using standard 0.18 um CMOS technology which is applicable in telecommunication has been reported. A two-stage, common-gate in cascade with cascode, UWB LNA has been proposed to achieve more than 10 dB input and output return loss, maximum gain of 26 dB, and NF of 2.9 dB over the full frequency band. The proposed LNA consumes 10 mW from 1.8 V supply. The designed LNA has an excellent high gain in comparison with previous works.

  16. Sampled sinusoidal stimulation profile and multichannel fuzzy logic classification for monitor-based phase-coded SSVEP brain-computer interfacing

    NASA Astrophysics Data System (ADS)

    Manyakov, Nikolay V.; Chumerin, Nikolay; Robben, Arne; Combaz, Adrien; van Vliet, Marijn; Van Hulle, Marc M.

    2013-06-01

    Objective. The performance and usability of brain-computer interfaces (BCIs) can be improved by new paradigms, stimulation methods, decoding strategies, sensor technology etc. In this study we introduce new stimulation and decoding methods for electroencephalogram (EEG)-based BCIs that have targets flickering at the same frequency but with different phases. Approach. The phase information is estimated from the EEG data, and used for target command decoding. All visual stimulation is done on a conventional (60-Hz) LCD screen. Instead of the ‘on/off’ visual stimulation, commonly used in phase-coded BCI, we propose one based on a sampled sinusoidal intensity profile. In order to fully exploit the circular nature of the evoked phase response, we introduce a filter feature selection procedure based on circular statistics and propose a fuzzy logic classifier designed to cope with circular information from multiple channels jointly. Main results. We show that the proposed visual stimulation enables us not only to encode more commands under the same conditions, but also to obtain EEG responses with a more stable phase. We also demonstrate that the proposed decoding approach outperforms existing ones, especially for the short time windows used. Significance. The work presented here shows how to overcome some of the limitations of screen-based visual stimulation. The superiority of the proposed decoding approach demonstrates the importance of preserving the circularity of the data during the decoding stage.

  17. A case study on the feasibility and performance of an UWB-AoA real time location system for resources management of civil construction projects

    NASA Astrophysics Data System (ADS)

    Mok, Esmond; Xia, Linyuan; Retscher, Guenther; Tian, Hui

    2010-06-01

    The application of integrated satellite and modern wireless positioning technologies for ubiquitous real-time resources management in large scale civil engineering projects can greatly optimize the time and cost in the construction process, and is now the trend for modern construction project management. As the outdoor conditions of most civil construction sites are open to sky, satellite positioning with the popularly used Global Positioning System (GPS) has been proved to be very efficient and effective. However, the condition in indoor and underground construction site is very complicated due to the fact that different construction activities would be carried out in different congested areas, involving heavy construction plant, equipment, professionals and technical personnel. Nowadays different emerging technologies such as Wi-Fi and ZigBee can be adopted for position and tracking in indoor environments. Nevertheless, under the very complicated construction site conditions these technologies may fail due to movement of human resources and construction plant, variation of metrological conditions, and serious multipath effects of signals. It is considered that Ultra Wide Band (UWB) technology is more suitable for indoor construction site environments. In this paper, a case study on the attempt of integrating GPS with Ubisense Real-time Location System (RTLS) for resources management in an underground railway construction site is discussed. Laboratory and field tests have shown that the RTLS can provide better resources management capability in terms of positioning accuracy and stability than Wi-Fi and ZigBee technologies under complicated construction environments. The test results show that the system can normally achieve better than 15 cm accuracy, and better than 1 m under adverse geometrical site condition. However, the high instrumental set up cost and the requirement for high quality data transmission cable for high precision time synchronization between

  18. Design and Performance Evaluation of a UWB Communication and Tracking System for Mini-AERCam

    NASA Technical Reports Server (NTRS)

    Barton, Richard J.

    2005-01-01

    be a passive component of the communication system which will need to operate in a time-varying multipath environment created as the robot camera moves over the ISS structure. In addition, due to many interference sources located on the ISS, SSO, LEO satellites and ground-based transmitters, selecting a frequency for the ISS and Mini-AERCam link which will coexist with all interferers poses a major design challenge. To meet all of these challenges, ultrawideband (UWB) radio technology is being studied for use in the Mini-AERCam communication and tracking subsystem. The research described in this report is focused on design and evaluation of passive tracking system algorithms based on UWB radio transmissions from mini-AERCam.

  19. Ultrawide band signal analysis in urban environment

    NASA Astrophysics Data System (ADS)

    Schiavone, Guy A.; Palaniappan, Ravishankar; Tracy, Judd; Wahid, Parveen; Dere, Troy P.

    2002-06-01

    Ultra-wide band (UWB) is a relatively new term used to describe a technology that has been known since the 1960's as carrier free, baseband or impulse technology. The basic concept is to develop, transmit and receive an extremely short duration burst of radio frequency energy-typically a few tens of pico seconds to a few nanoseconds in duration. The resultant waveforms are extremely broadband, so much so that it is often difficult to determine an actual RF center frequency- thus the term carrier free. Since UWB waveforms are of such short time duration, they have some rather unique properties. In communications, for example, UWB pulses can be used to provide extremely high data rate performance in multi-user network applications [1]. For radar applications, these same pulses can provide very fine range resolution and precision distance and/or positioning measurement capabilities. These short duration waveforms are relatively immune to multi-path cancellation effects as observed in mobile and in-building environments. As a consequence, UWB systems are particularly well suited for high-speed, mobile wireless applications. As bandwidth is inversely related to pulse duration, the spectral extent of these waveforms can be made quite large. With proper engineering design, the resultant energy densities (i.e., transmitted watts of power per unit hertz of bandwidth) can be quite low. This low energy density translates into a low probability of detection (LPD) RF signature. An LPD signature is of particular interest for military applications (e.g., for covert communications and radar); however, an LPD signature also produces minimal interference to proximity systems and minimal RF health hazards, significant for both military and commercial applications. In this paper we consider the development of a simulation model to calculate ultra-wide band signal propagation characteristics in urban indoor and outdoor environments. The simulation is accomplished using a hybrid model

  20. A CPW-Fed Circular Wide-Slot UWB Antenna with Wide Tunable and Flexible Reconfigurable Dual Notch Bands

    PubMed Central

    Li, Yingsong; Li, Wenxing; Ye, Qiubo

    2013-01-01

    A coplanar waveguide (CPW)-fed circular slot antenna with wide tunable dual band-notched function and frequency reconfigurable characteristic is designed, and its performance is verified experimentally for ultra-wideband (UWB) communication applications. The dual band-notched function is achieved by using a T-shaped stepped impedance resonator (T-SIR) inserted inside the circular ring radiation patch and by etching a parallel stub loaded resonator (PSLR) in the CPW transmission line, while the wide tunable bands can be implemented by adjusting the dimensions of the T-SIR and the PSLR. The notch band reconfigurable characteristic is realized by integrating three switches into the T-SIR and the PSLR. The numerical and experimental results show that the proposed antenna has a wide bandwidth ranging from 2.7 GHz to 12 GHz with voltage standing wave ratio (VSWR) less than 2, except for the two notch bands operating at 3.8–5.9 GHz and 7.7–9.2 GHz, respectively. In addition, the proposed antenna has been optimized to a compact size and can provide omnidirectional radiation patterns, which are suitable for UWB communication applications. PMID:24222733

  1. A Miniaturized Antenna with Negative Index Metamaterial Based on Modified SRR and CLS Unit Cell for UWB Microwave Imaging Applications

    PubMed Central

    Islam, Md. Moinul; Islam, Mohammad Tariqul; Samsuzzaman, Md.; Faruque, Mohammad Rashed Iqbal; Misran, Norbahiah; Mansor, Mohd Fais

    2015-01-01

    A miniaturized antenna employing a negative index metamaterial with modified split-ring resonator (SRR) and capacitance-loaded strip (CLS) unit cells is presented for Ultra wideband (UWB) microwave imaging applications. Four left-handed (LH) metamaterial (MTM) unit cells are located along one axis of the antenna as the radiating element. Each left-handed metamaterial unit cell combines a modified split-ring resonator (SRR) with a capacitance-loaded strip (CLS) to obtain a design architecture that simultaneously exhibits both negative permittivity and negative permeability, which ensures a stable negative refractive index to improve the antenna performance for microwave imaging. The antenna structure, with dimension of 16 × 21 × 1.6 mm3, is printed on a low dielectric FR4 material with a slotted ground plane and a microstrip feed. The measured reflection coefficient demonstrates that this antenna attains 114.5% bandwidth covering the frequency band of 3.4–12.5 GHz for a voltage standing wave ratio of less than 2 with a maximum gain of 5.16 dBi at 10.15 GHz. There is a stable harmony between the simulated and measured results that indicate improved nearly omni-directional radiation characteristics within the operational frequency band. The stable surface current distribution, negative refractive index characteristic, considerable gain and radiation properties make this proposed negative index metamaterial antenna optimal for UWB microwave imaging applications. PMID:28787945

  2. A Miniaturized Antenna with Negative Index Metamaterial Based on Modified SRR and CLS Unit Cell for UWB Microwave Imaging Applications.

    PubMed

    Islam, Md Moinul; Islam, Mohammad Tariqul; Samsuzzaman, Md; Faruque, Mohammad Rashed Iqbal; Misran, Norbahiah; Mansor, Mohd Fais

    2015-01-23

    A miniaturized antenna employing a negative index metamaterial with modified split-ring resonator (SRR) and capacitance-loaded strip (CLS) unit cells is presented for Ultra wideband (UWB) microwave imaging applications. Four left-handed (LH) metamaterial (MTM) unit cells are located along one axis of the antenna as the radiating element. Each left-handed metamaterial unit cell combines a modified split-ring resonator (SRR) with a capacitance-loaded strip (CLS) to obtain a design architecture that simultaneously exhibits both negative permittivity and negative permeability, which ensures a stable negative refractive index to improve the antenna performance for microwave imaging. The antenna structure, with dimension of 16 × 21 × 1.6 mm³, is printed on a low dielectric FR4 material with a slotted ground plane and a microstrip feed. The measured reflection coefficient demonstrates that this antenna attains 114.5% bandwidth covering the frequency band of 3.4-12.5 GHz for a voltage standing wave ratio of less than 2 with a maximum gain of 5.16 dBi at 10.15 GHz. There is a stable harmony between the simulated and measured results that indicate improved nearly omni-directional radiation characteristics within the operational frequency band. The stable surface current distribution, negative refractive index characteristic, considerable gain and radiation properties make this proposed negative index metamaterial antenna optimal for UWB microwave imaging applications.

  3. A CPW-fed circular wide-slot UWB antenna with wide tunable and flexible reconfigurable dual notch bands.

    PubMed

    Li, Yingsong; Li, Wenxing; Ye, Qiubo

    2013-01-01

    A coplanar waveguide (CPW)-fed circular slot antenna with wide tunable dual band-notched function and frequency reconfigurable characteristic is designed, and its performance is verified experimentally for ultra-wideband (UWB) communication applications. The dual band-notched function is achieved by using a T-shaped stepped impedance resonator (T-SIR) inserted inside the circular ring radiation patch and by etching a parallel stub loaded resonator (PSLR) in the CPW transmission line, while the wide tunable bands can be implemented by adjusting the dimensions of the T-SIR and the PSLR. The notch band reconfigurable characteristic is realized by integrating three switches into the T-SIR and the PSLR. The numerical and experimental results show that the proposed antenna has a wide bandwidth ranging from 2.7 GHz to 12 GHz with voltage standing wave ratio (VSWR) less than 2, except for the two notch bands operating at 3.8-5.9 GHz and 7.7-9.2 GHz, respectively. In addition, the proposed antenna has been optimized to a compact size and can provide omnidirectional radiation patterns, which are suitable for UWB communication applications.

  4. Spectrum-averaged Harmonic Path (SHAPA) algorithm for non-contact vital sign monitoring with ultra-wideband (UWB) radar.

    PubMed

    Van Nguyen; Javaid, Abdul Q; Weitnauer, Mary Ann

    2014-01-01

    We introduce the Spectrum-averaged Harmonic Path (SHAPA) algorithm for estimation of heart rate (HR) and respiration rate (RR) with Impulse Radio Ultrawideband (IR-UWB) radar. Periodic movement of human torso caused by respiration and heart beat induces fundamental frequencies and their harmonics at the respiration and heart rates. IR-UWB enables capture of these spectral components and frequency domain processing enables a low cost implementation. Most existing methods of identifying the fundamental component either in frequency or time domain to estimate the HR and/or RR lead to significant error if the fundamental is distorted or cancelled by interference. The SHAPA algorithm (1) takes advantage of the HR harmonics, where there is less interference, and (2) exploits the information in previous spectra to achieve more reliable and robust estimation of the fundamental frequency in the spectrum under consideration. Example experimental results for HR estimation demonstrate how our algorithm eliminates errors caused by interference and produces 16% to 60% more valid estimates.

  5. A progressive processing method for breast cancer detection via UWB based on an MRI-derived model

    NASA Astrophysics Data System (ADS)

    Xiao, Xia; Song, Hang; Wang, Zong-Jie; Wang, Liang

    2014-07-01

    Ultra-wideband (UWB) microwave imaging is a promising method for breast cancer detection based on the large contrast of electric parameters between the malignant tumor and its surrounded normal breast organisms. In the case of multiple tumors being present, the conventional imaging approaches may be ineffective to detect all the tumors clearly. In this paper, a progressive processing method is proposed for detecting more than one tumor. The method is divided into three stages: primary detection, refocusing and image optimization. To test the feasibility of the approach, a numerical breast model is developed based on the realistic magnetic resonance image (MRI). Two tumors are assumed embedded in different positions. Successful detection of a 3.6 mm-diameter tumor at a depth of 42 mm is achieved. The correct information of both tumors is shown in the reconstructed image, suggesting that the progressive processing method is promising for multi-tumor detection.

  6. Design and Analysis of Miniaturized Microstrip Patch Antenna with Metamaterials Based on Modified Split-Ring Resonator for UWB Applications

    NASA Astrophysics Data System (ADS)

    Khedrouche, D.; Bougoutaia, T.; Hocini, A.

    2016-11-01

    In this paper, a miniaturized microstrip patch antenna using a negative index metamaterial with modified split-ring resonator (SRR) unit cells is proposed for ultra-wideband (UWB) applications. The new design of metamaterial based microstrip patch antenna has been optimized to provide an improved bandwidth and multiple frequency operations. All the antenna performance parameters are presented in response-graphs. Also it is mentioned that the physical dimensions of the metamaterial based patch antenna are very small, which is convenient to modern communication. A 130 % bandwidth, covering the frequency band of 2.9-13.5 GHz, (for return loss less than or equal -10 dB) is achieved, which allow the antenna to operate in the Federal Communication Commission (FCC) band. In addition, the antenna has a good radiation pattern in the ultra-wide band spectrum, and it is nearly omnidirectional.

  7. A Negative Index Metamaterial-Inspired UWB Antenna with an Integration of Complementary SRR and CLS Unit Cells for Microwave Imaging Sensor Applications

    PubMed Central

    Islam, Mohammad Tariqul; Islam, Md. Moinul; Samsuzzaman, Md.; Faruque, Mohammad Rashed Iqbal; Misran, Norbahiah

    2015-01-01

    This paper presents a negative index metamaterial incorporated UWB antenna with an integration of complementary SRR (split-ring resonator) and CLS (capacitive loaded strip) unit cells for microwave imaging sensor applications. This metamaterial UWB antenna sensor consists of four unit cells along one axis, where each unit cell incorporates a complementary SRR and CLS pair. This integration enables a design layout that allows both a negative value of permittivity and a negative value of permeability simultaneous, resulting in a durable negative index to enhance the antenna sensor performance for microwave imaging sensor applications. The proposed MTM antenna sensor was designed and fabricated on an FR4 substrate having a thickness of 1.6 mm and a dielectric constant of 4.6. The electrical dimensions of this antenna sensor are 0.20 λ × 0.29 λ at a lower frequency of 3.1 GHz. This antenna sensor achieves a 131.5% bandwidth (VSWR < 2) covering the frequency bands from 3.1 GHz to more than 15 GHz with a maximum gain of 6.57 dBi. High fidelity factor and gain, smooth surface-current distribution and nearly omni-directional radiation patterns with low cross-polarization confirm that the proposed negative index UWB antenna is a promising entrant in the field of microwave imaging sensors. PMID:26007721

  8. A Negative Index Metamaterial-Inspired UWB Antenna with an Integration of Complementary SRR and CLS Unit Cells for Microwave Imaging Sensor Applications.

    PubMed

    Islam, Mohammad Tariqul; Islam, Md Moinul; Samsuzzaman, Md; Faruque, Mohammad Rashed Iqbal; Misran, Norbahiah

    2015-05-20

    This paper presents a negative index metamaterial incorporated UWB antenna with an integration of complementary SRR (split-ring resonator) and CLS (capacitive loaded strip) unit cells for microwave imaging sensor applications. This metamaterial UWB antenna sensor consists of four unit cells along one axis, where each unit cell incorporates a complementary SRR and CLS pair. This integration enables a design layout that allows both a negative value of permittivity and a negative value of permeability simultaneous, resulting in a durable negative index to enhance the antenna sensor performance for microwave imaging sensor applications. The proposed MTM antenna sensor was designed and fabricated on an FR4 substrate having a thickness of 1.6 mm and a dielectric constant of 4.6. The electrical dimensions of this antenna sensor are 0.20 λ × 0.29 λ at a lower frequency of 3.1 GHz. This antenna sensor achieves a 131.5% bandwidth (VSWR < 2) covering the frequency bands from 3.1 GHz to more than 15 GHz with a maximum gain of 6.57 dBi. High fidelity factor and gain, smooth surface-current distribution and nearly omni-directional radiation patterns with low cross-polarization confirm that the proposed negative index UWB antenna is a promising entrant in the field of microwave imaging sensors.

  9. Analysis of Ultra Wide Band (UWB) Technology for an Indoor Geolocation and Physiological Monitoring System

    DTIC Science & Technology

    2002-03-12

    highly resistant to interference. This is critical as all other signals within the band occupied by a time- modulated signal act as jammers to the...sensitive to interference from cell phones, pagers, 802.11 and Bluetooth devices. Equally limiting are government and safety restrictions placed on...spectrum restrictions, which exist across international borders. A problem exists since a non-interfering radio in one country becomes a jammer in

  10. On the Analysis of the Dynamics and Synchronization of Chaotic Modulation and Demodulation in UWB Communication and Positioning Systems

    NASA Astrophysics Data System (ADS)

    Chedjou, J. C.; Dada, J. P.; Moussa, I.; Takenga, C.; Anne, R.; Kyamakya, K.

    This paper studies synchronization transitions in a system of coupled non-identical self-sustained chaotic oscillators of the Rössler type. The interest devoted to the Rössler oscillators is motivated by their capability to behave chaotically at very high frequencies. Both phase synchronization and lag synchronization are analyzed in terms of a coupling parameter. It is shown that both types of synchronization can be achieved when monitoring a coupling parameter. The advantage of using one parameter to insure both types of synchronization is found in practical realizations. Indeed one should monitor only one resistor to predict the boundaries of the control resistor for the occurrence of each type of synchronization. Another advantage of monitoring only one resistor is found in the accuracy of results. An experimental study of the synchronization is carried out. Experimental waveforms in the drive and response systems are obtained. The waveforms are compared to confirm the achievement of sync hronization experimentally. One of the advantages of using analog simulation in this work is the possibility to analyze the behaviour of the coupled system at very high frequencies by performing an appropriate time scaling. This offers the possibility of using our coupled system for Ultra-wideband (UWB) applications.

  11. The Applications of Decision-Level Data Fusion Techniques in the Field of Multiuser Detection for DS-UWB Systems.

    PubMed

    Gu, Yebo; Yang, Minglei; Shi, Zhenguo; Wu, Zhilu

    2015-09-25

    In this paper, the decision-level data fusion techniques are extended to the multiuser detection (MUD) field. Then two novel MUD algorithms, that is the chairman arbitrating decision-level fusion criterion (CA-DFC) based MUD algorithm and the veto logic decision-level fusion criterion (VL-DFC) based MUD algorithm, are proposed for DS-UWB communication systems. In CA-DFC based method, the chairman can make his arbitration among the preliminary decisions from sub-optimal detectors by his own rule. In the VL-DFC based method, the undetermined bits in these preliminary decisions are considered to construct a simplified solution space, and then the chairman can make his final decision within this space. Simulation results demonstrate that the performances of CA-DFC and VL-DFC based MUD algorithms are superior to those of other sub-optimal MUD algorithms, and even close to that of OMD. Moreover, both of these proposed algorithms have lower computational complexity than OMD, which reveals their efficiency. Compared with CA-DFC, VL-DFC based algorithm achieves a little improvement in its performance, at the cost of the increment in its computational complexity. Thus, they can be applied to different practical situations.

  12. Adaptive modulation and intra-symbol frequency-domain averaging scheme for multiband OFDM UWB over fiber system

    NASA Astrophysics Data System (ADS)

    He, Jing; Li, Teng; Wen, Xuejie; Deng, Rui; Chen, Ming; Chen, Lin

    2016-01-01

    To overcome the unbalanced error bit distribution among subcarriers caused by inter-subcarriers mixing interference (ISMI) and frequency selective fading (FSF), an adaptive modulation scheme based on 64/16/4QAM modulation is proposed and experimentally investigated in the intensity-modulation direct-detection (IM/DD) multiband orthogonal frequency division multiplexing (MB-OFDM) ultra-wideband (UWB) over fiber system. After 50 km standard single mode fiber (SSMF) transmission, at the bit error ratio (BER) of 1×10-3, the experimental results show that the power penalty of the IM/DD MB-OFDM UWBoF system with 64/16/4QAM adaptive modulation scheme is about 3.6 dB, compared to that with the 64QAM modulation scheme. Moreover, the receiver sensitivity has been improved about 0.52 dB when the intra-symbol frequency-domain averaging (ISFA) algorithm is employed in the IM/DD MB-OFDM UWBoF system based on the 64/16/4QAM adaptive modulation scheme. Meanwhile, after 50 km SSMF transmission, there is a negligible power penalty in the adaptively modulated IM/DD MB-OFDM UWBoF system, compared to the optical back-to-back case.

  13. The Applications of Decision-Level Data Fusion Techniques in the Field of Multiuser Detection for DS-UWB Systems

    PubMed Central

    Gu, Yebo; Yang, Minglei; Shi, Zhenguo; Wu, Zhilu

    2015-01-01

    In this paper, the decision-level data fusion techniques are extended to the multiuser detection (MUD) field. Then two novel MUD algorithms, that is the chairman arbitrating decision-level fusion criterion (CA-DFC) based MUD algorithm and the veto logic decision-level fusion criterion (VL-DFC) based MUD algorithm, are proposed for DS-UWB communication systems. In CA-DFC based method, the chairman can make his arbitration among the preliminary decisions from sub-optimal detectors by his own rule. In the VL-DFC based method, the undetermined bits in these preliminary decisions are considered to construct a simplified solution space, and then the chairman can make his final decision within this space. Simulation results demonstrate that the performances of CA-DFC and VL-DFC based MUD algorithms are superior to those of other sub-optimal MUD algorithms, and even close to that of OMD. Moreover, both of these proposed algorithms have lower computational complexity than OMD, which reveals their efficiency. Compared with CA-DFC, VL-DFC based algorithm achieves a little improvement in its performance, at the cost of the increment in its computational complexity. Thus, they can be applied to different practical situations. PMID:26404273

  14. 30 pJ/b, 67 Mbps, Centimeter-to-Meter Range Data Telemetry With an IR-UWB Wireless Link.

    PubMed

    Ebrazeh, Ali; Mohseni, Pedram

    2015-06-01

    This paper reports an energy-efficient, impulse radio ultra wideband (IR-UWB) wireless link operating in 3-5 GHz for data telemetry over centimeter-to-meter range distances at rates extended to tens of Mbps. The link comprises an all-digital, integrated transmitter (TX) fabricated in 90 nm 1P/9M CMOS that incorporates a waveform-synthesis pulse generator and a timing generator for on-off-keying (OOK) pulse modulation and phase scrambling. The link also incorporates an energy-detection receiver (RX) realized with commercial off-the-shelf (COTS) components that performs radio-frequency (RF) filtering, amplification, logarithmic power detection for data demodulation and automatic level control for robust operation in the presence of distance variations. Employing a miniaturized, UWB, chip antenna for the TX and RX, wireless transmission of pseudo-random binary sequence (PRBS) data at rates up to 50 Mbps over 10 cm-1 m is shown. Further, employing a high-gain horn antenna for the RX, wireless transmission of PRBS data at rates up to 67 Mbps over 50 cm-4 m is shown with a TX energy consumption of 30 pJ/b (i.e., power consumption of 2 mW) from 1.2 V. The measured bit error rate (BER) in both cases is < 10(-7) . Results from wireless recording of the background current of a carbon-fiber microelectrode (CFM) in one fast-scan cyclic voltammetry (FSCV) scan using the IR-UWB link are also included, exhibiting excellent match with those obtained from a conventional frequency-shift-keyed (FSK) link at ~433 MHz.

  15. Two-phase flow in a diverging nozzle. Comparison between a new formula for the pressure rise in an expansion and numerical calculation using two-phase codes with experimental data

    NASA Astrophysics Data System (ADS)

    Wadle, M.

    1986-05-01

    Stationary two phase flow of steam-water and air-water mixtures in a well instrumented horizontal diverging nozzle was investigated. The test section consists of a constant diameter tube, a friction section followed by an expansion (the diffusor) which has a tan h contour, and another constant diameter tube. The initial conditions were varied to achieve subcritical and critical mass flow rates. The agreement between the experimentally determined pressure recovery in the nozzle expansion and seven analytical models is poor. A model based on the superficial velocity concept shows good agreement. Calculation with the two phase code DUESE shows that in the diffusion mechanical nonequilibrium prevails, while thermodynamic nonequilibrium has only a small effect.

  16. Customization of UWB 3D-RTLS Based on the New Uncertainty Model of the AoA Ranging Technique

    PubMed Central

    Jachimczyk, Bartosz; Dziak, Damian; Kulesza, Wlodek J.

    2017-01-01

    The increased potential and effectiveness of Real-time Locating Systems (RTLSs) substantially influence their application spectrum. They are widely used, inter alia, in the industrial sector, healthcare, home care, and in logistic and security applications. The research aims to develop an analytical method to customize UWB-based RTLS, in order to improve their localization performance in terms of accuracy and precision. The analytical uncertainty model of Angle of Arrival (AoA) localization in a 3D indoor space, which is the foundation of the customization concept, is established in a working environment. Additionally, a suitable angular-based 3D localization algorithm is introduced. The paper investigates the following issues: the influence of the proposed correction vector on the localization accuracy; the impact of the system’s configuration and LS’s relative deployment on the localization precision distribution map. The advantages of the method are verified by comparing them with a reference commercial RTLS localization engine. The results of simulations and physical experiments prove the value of the proposed customization method. The research confirms that the analytical uncertainty model is the valid representation of RTLS’ localization uncertainty in terms of accuracy and precision and can be useful for its performance improvement. The research shows, that the Angle of Arrival localization in a 3D indoor space applying the simple angular-based localization algorithm and correction vector improves of localization accuracy and precision in a way that the system challenges the reference hardware advanced localization engine. Moreover, the research guides the deployment of location sensors to enhance the localization precision. PMID:28125056

  17. Customization of UWB 3D-RTLS Based on the New Uncertainty Model of the AoA Ranging Technique.

    PubMed

    Jachimczyk, Bartosz; Dziak, Damian; Kulesza, Wlodek J

    2017-01-25

    The increased potential and effectiveness of Real-time Locating Systems (RTLSs) substantially influence their application spectrum. They are widely used, inter alia, in the industrial sector, healthcare, home care, and in logistic and security applications. The research aims to develop an analytical method to customize UWB-based RTLS, in order to improve their localization performance in terms of accuracy and precision. The analytical uncertainty model of Angle of Arrival (AoA) localization in a 3D indoor space, which is the foundation of the customization concept, is established in a working environment. Additionally, a suitable angular-based 3D localization algorithm is introduced. The paper investigates the following issues: the influence of the proposed correction vector on the localization accuracy; the impact of the system's configuration and LS's relative deployment on the localization precision distribution map. The advantages of the method are verified by comparing them with a reference commercial RTLS localization engine. The results of simulations and physical experiments prove the value of the proposed customization method. The research confirms that the analytical uncertainty model is the valid representation of RTLS' localization uncertainty in terms of accuracy and precision and can be useful for its performance improvement. The research shows, that the Angle of Arrival localization in a 3D indoor space applying the simple angular-based localization algorithm and correction vector improves of localization accuracy and precision in a way that the system challenges the reference hardware advanced localization engine. Moreover, the research guides the deployment of location sensors to enhance the localization precision.

  18. A RF receiver frontend for SC-UWB in a 0.18-μm CMOS process

    NASA Astrophysics Data System (ADS)

    Rui, Guo; Haiying, Zhang

    2012-12-01

    A radio frequency (RF) receiver frontend for single-carrier ultra-wideband (SC-UWB) is presented. The front end employs direct-conversion architecture, and consists of a differential low noise amplifier (LNA), a quadrature mixer, and two intermediate frequency (IF) amplifiers. The proposed LNA employs source inductively degenerated topology. First, the expression of input impedance matching bandwidth in terms of gate-source capacitance, resonant frequency and target S11 is given. Then, a noise figure optimization strategy under gain and power constraints is proposed, with consideration of the integrated gate inductor, the bond-wire inductance, and its variation. The LNA utilizes two stages with different resonant frequencies to acquire flat gain over the 7.1-8.1 GHz frequency band, and has two gain modes to obtain a higher receiver dynamic range. The mixer uses a double balanced Gilbert structure. The front end is fabricated in a TSMC 0.18-μm RF CMOS process and occupies an area of 1.43 mm2. In high and low gain modes, the measured maximum conversion gain are 42 dB and 22 dB, input 1 dB compression points are -40 dBm and -20 dBm, and S11 is better than -18 dB and -14.5 dB. The 3 dB IF bandwidth is more than 500 MHz. The double sideband noise figure is 4.7 dB in high gain mode. The total power consumption is 65 mW from a 1.8 V supply.

  19. Low-Rank Matrix Recovery Approach for Clutter Rejection in Real-Time IR-UWB Radar-Based Moving Target Detection

    PubMed Central

    Sabushimike, Donatien; Na, Seung You; Kim, Jin Young; Bui, Ngoc Nam; Seo, Kyung Sik; Kim, Gil Gyeom

    2016-01-01

    The detection of a moving target using an IR-UWB Radar involves the core task of separating the waves reflected by the static background and by the moving target. This paper investigates the capacity of the low-rank and sparse matrix decomposition approach to separate the background and the foreground in the trend of UWB Radar-based moving target detection. Robust PCA models are criticized for being batched-data-oriented, which makes them inconvenient in realistic environments where frames need to be processed as they are recorded in real time. In this paper, a novel method based on overlapping-windows processing is proposed to cope with online processing. The method consists of processing a small batch of frames which will be continually updated without changing its size as new frames are captured. We prove that RPCA (via its Inexact Augmented Lagrange Multiplier (IALM) model) can successfully separate the two subspaces, which enhances the accuracy of target detection. The overlapping-windows processing method converges on the optimal solution with its batch counterpart (i.e., processing batched data with RPCA), and both methods prove the robustness and efficiency of the RPCA over the classic PCA and the commonly used exponential averaging method. PMID:27598159

  20. Low-Rank Matrix Recovery Approach for Clutter Rejection in Real-Time IR-UWB Radar-Based Moving Target Detection.

    PubMed

    Sabushimike, Donatien; Na, Seung You; Kim, Jin Young; Bui, Ngoc Nam; Seo, Kyung Sik; Kim, Gil Gyeom

    2016-09-01

    The detection of a moving target using an IR-UWB Radar involves the core task of separating the waves reflected by the static background and by the moving target. This paper investigates the capacity of the low-rank and sparse matrix decomposition approach to separate the background and the foreground in the trend of UWB Radar-based moving target detection. Robust PCA models are criticized for being batched-data-oriented, which makes them inconvenient in realistic environments where frames need to be processed as they are recorded in real time. In this paper, a novel method based on overlapping-windows processing is proposed to cope with online processing. The method consists of processing a small batch of frames which will be continually updated without changing its size as new frames are captured. We prove that RPCA (via its Inexact Augmented Lagrange Multiplier (IALM) model) can successfully separate the two subspaces, which enhances the accuracy of target detection. The overlapping-windows processing method converges on the optimal solution with its batch counterpart (i.e., processing batched data with RPCA), and both methods prove the robustness and efficiency of the RPCA over the classic PCA and the commonly used exponential averaging method.

  1. Subsurface Imaging by UWB Radar: Application to Humanitarian Demining in Cambodia

    NASA Astrophysics Data System (ADS)

    Sato, Motoyuki

    Ground Penetrating Radar (GPR) has been widely used applications which include detection of subsurface facilities, concrete inspection and archaeology. Among these applications, humanitarian demining is still difficult task. Since 2002, we have developed a new hand-held land mine detection dual-sensor ALIS. ALIS is equipped with a metal detector and a GPR, and it has a sensor tracking system, which can record the GPR and Metal detector signal with its location. ALIS can process the data and is used for image re-construction by migration processing. ALIS is the only one mine detection system in the world which can visualize the GPR image by hand scanning. We found that the migration processing can reduce the clutter and gives us clear images of buried mines. After several tests of ALIS in mine affected courtiers, operation of ALIS in mine fields in Cambodia started in summer 2009. Two sets of ALIS have been operated in Cambodia and more than 77 antipersonnel mines have been detected and 137,000m2 farmland was cleaned.

  2. On phaser-based processing of impulse radio UWB over fiber systems employing SOA

    NASA Astrophysics Data System (ADS)

    Taki, H.; Azou, S.; Hamie, A.; Al Housseini, A.; Alaeddine, A.; Sharaiha, A.

    2017-07-01

    In this study, we adopt a phaser-based processing to enhance the performance of impulse radio over fiber system utilizing SOA. The amplifier has been placed at a distance in the optical link, so as to extend the coverage area of proposed transceiver. Operating in the linear or saturation region for SOA, adds ASE noise or strong nonlinearities acting on the propagated pulses, respectively. Both lead to a degradation in the power efficiency and bit error rate performance. By applying up and down analog chirping technique, we have reduced the ASE power and nonlinearity simultaneously. Based on the 5th Gaussian pulse and Abraha's combination of doublets, a significant improvement has been achieved at extremely low and high input powers entering the amplifier (<-15 dBm and 0 dBm), recording a very good bit error rate performance and power efficiency. Better signal quality was observed after photo-detector, due to the fact that waveforms with lower frequency components are less affected by SOA nonlinearity. Our scheme has proved to be effective for 1 Gbps OOK and 0.5 Gbps PPM transmissions, while reaching a distance of 160 km in the optical fiber.

  3. Realistic modeling of the biological channel for the design of implantable wireless UWB communication systems.

    PubMed

    Bahrami, Hadi; Gosselin, Benoit; Rusch, Leslie A

    2012-01-01

    Several emerging medical applications require that a miniature data acquisition device be implanted into the head to extract and wirelessly communicate brain activity to other devices. Designing a reliable communication link for such an application requires a realistic model of the surrounding biological tissues. This paper exploits a realistic model of the biological channel to design a suitable wireless ultra wideband communication link in a brain monitoring application. Two scenarios for positioning the implanted transmitting antenna are considered. The 1(st) scenario places the antenna under the skull, whereas the 2(nd) scenario places the antenna under the skin, above the skull. The propagation characteristics of the signal through the tissues of the human head have been determined with full-wave electromagnetic simulation based on Finite Element Method. The implantable antenna and the external antenna are key components to establish an electromagnetic link between an implanted transmitter and an external receiver. The average specific absorption rate (ASAR) of the implantable antennas are evaluated and compared for the two proposed scenarios. Moreover, the maximum available power from the implanted antenna is evaluated to characterize the performance of the communication link established between the implantable antenna and the external antenna, with respect to spectrum and safety regulations. We show how sensitive the receiver must be in order to implement a reliable telemetry link based on the proposed model of the channel.

  4. Covert communications using random noise signals: overall system simulation and modulation analysis

    NASA Astrophysics Data System (ADS)

    Chuang, Jack; Narayanan, Ram M.

    2005-06-01

    In military communications, there exist numerous potential threats to message security. Ultra-wideband (UWB) signals provide secure communications because they cannot, in general, be detected using conventional receivers and they can be made relatively immune from jamming. The security of an UWB signal can be further improved by mixing it with random noise. By using a random noise signal, the user can conceal the message signal within the noise waveform and thwart detection by hostile forces. This paper describes a novel spread spectrum technique that can be used for secure and covert communications. The technique is based on the use of heterodyne correlation techniques to inject coherence in a random noise signal. The modulated signal to be transmitted containing the coherent carrier is mixed with a sample of an ultrawideband random noise signal. The frequency range of the ultra-wideband noise signal is appropriately chosen so that the lower sideband of the mixing process falls over the same frequency range. Both the frequency-converted noise-like signal and the original random noise signal are simultaneously transmitted on orthogonally polarized channels through a dual-polarized transmitting antenna. The receiver consists of a similar dual-polarized antenna that simultaneously receives the two orthogonally polarized transmitted signals, amplifies each in a minimum phase limiting amplifier, and mixes these signals in a double sideband up-converter. The upper sideband of the mixing process recovers the modulated signal, which can then be demodulated. The advantage of this technique lies in the relative immunity of the random noise-like un-polarized transmit signal from detection and jamming. Since the transmit signal "appears" totally un-polarized and noise-like, linearly polarized receivers are unable to identify, decode, or otherwise extract useful information from the signal. The system is immune from interference caused by high power linearly polarized signal

  5. Signal and Image Processing Algorithms for the U.S. Army Research Laboratory Ultra-wideband (UWB) Synchronous Impulse Reconstruction (SIRE) Radar

    DTIC Science & Technology

    2009-04-01

    8. PERFORMING ORGANIZATION REPORT NUMBER ARL-TR-4784 10 . SPONSOR/MONITOR’S ACRONYM(S) 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES...acquisition technique. ...................................8 Figure 10 . The SIRE transmitting pulse in the time-domain and frequency-domain... 10 Figure 11. False color plot of one complete frame of radar data: 16 receiving records using the left transmitter and 16 receiving

  6. Techniques for Clutter Suppression in the Presence of Body Movements during the Detection of Respiratory Activity through UWB Radars

    PubMed Central

    Lazaro, Antonio; Girbau, David; Villarino, Ramon

    2014-01-01

    This paper focuses on the feasibility of tracking the chest wall movement of a human subject during respiration from the waveforms recorded using an impulse-radio (IR) ultra-wideband radar. The paper describes the signal processing to estimate sleep apnea detection and breathing rate. Some techniques to solve several problems in these types of measurements, such as the clutter suppression, body movement and body orientation detection are described. Clutter suppression is achieved using a moving averaging filter to dynamically estimate it. The artifacts caused by body movements are removed using a threshold method before analyzing the breathing signal. The motion is detected using the time delay that maximizes the received signal after a clutter removing algorithm is applied. The periods in which the standard deviations of the time delay exceed a threshold are considered macro-movements and they are neglected. The sleep apnea intervals are detected when the breathing signal is below a threshold. The breathing rate is determined from the robust spectrum estimation based on Lomb periodogram algorithm. On the other hand the breathing signal amplitude depends on the body orientation respect to the antennas, and this could be a problem. In this case, in order to maximize the signal-to-noise ratio, multiple sensors are proposed to ensure that the backscattered signal can be detected by at least one sensor, regardless of the direction the human subject is facing. The feasibility of the system is compared with signals recorded by a microphone. PMID:24514883

  7. Techniques for clutter suppression in the presence of body movements during the detection of respiratory activity through UWB radars.

    PubMed

    Lazaro, Antonio; Girbau, David; Villarino, Ramon

    2014-02-07

    This paper focuses on the feasibility of tracking the chest wall movement of a human subject during respiration from the waveforms recorded using an impulse-radio (IR) ultra-wideband radar. The paper describes the signal processing to estimate sleep apnea detection and breathing rate. Some techniques to solve several problems in these types of measurements, such as the clutter suppression, body movement and body orientation detection are described. Clutter suppression is achieved using a moving averaging filter to dynamically estimate it. The artifacts caused by body movements are removed using a threshold method before analyzing the breathing signal. The motion is detected using the time delay that maximizes the received signal after a clutter removing algorithm is applied. The periods in which the standard deviations of the time delay exceed a threshold are considered macro-movements and they are neglected. The sleep apnea intervals are detected when the breathing signal is below a threshold. The breathing rate is determined from the robust spectrum estimation based on Lomb periodogram algorithm. On the other hand the breathing signal amplitude depends on the body orientation respect to the antennas, and this could be a problem. In this case, in order to maximize the signal-to-noise ratio, multiple sensors are proposed to ensure that the backscattered signal can be detected by at least one sensor, regardless of the direction the human subject is facing. The feasibility of the system is compared with signals recorded by a microphone.

  8. Signal voter

    DOEpatents

    Goodwin, Roy L.

    1981-01-01

    A voter for providing a single accurate output signal that is derived from the closest two signal levels of three input signals, each of which signals represents a measurement of the same phenomena. By means of the voting circuit, the signals are first sorted by level of amplitude and then ranked as highest, middle or lowest. The highest or lowest signal that is furthest from the middle signal is rejected, while the other highest or lowest signal is selected for processing. The selected high or low signal is then averaged with the middle signal to provide the output signal.

  9. Signal voter

    SciTech Connect

    Goodwin, R.L.

    1981-04-28

    A voter for providing a single accurate output signal that is derived from the closest two signal levels of three input signals , each of which signals represents a measurement of the same phenomena. By means of the voting circuit, the signals are first sorted by level of amplitude and then ranked as highest, middle or lowest. The highest or lowest signal that is furthest from the middle signal is rejected, while the other highest or lowest signal is selected for processing. The selected high or low signal is then averaged with the middle signal to provide the output signal.

  10. A digital method for cycle identification of short-distance Loran-C signal

    NASA Astrophysics Data System (ADS)

    Zou, De-Cai; Bian, Yu-Jing; Wu, Hai-Tao; Li, Yun

    2005-12-01

    The algorithm to judge the peak-value of the Loran-C impulse signal is improved. The individual cycle of the simulated short-distance Loran-C impulse signal with the noise is identified and the phase coding information is derived from the computation based on the sampling data of the simulated Loran-C impulse signal. The validity of the improved algorithm is verified with MATLAB and this algorithm is simulated with MODELSIM. The results indicate that the digital identification of the individual cycle of the short-distance Loran-C signal with a certain signal-to-noise ratio is realized preliminarily using the improved algorithm and this algorithm is practical.

  11. Radar transponder apparatus and signal processing technique

    SciTech Connect

    Axline, R.M. Jr.; Sloan, G.R.; Spalding, R.E.

    1994-12-31

    An active, phase-coded, time-grating transponder and a synthetic-aperture radar (SAR) and signal processor means, in combination, allow the recognition and location of the transponder (tag) in the SAR image and allow communication of information messages from the transponder to the SAR. The SAR is an illuminating radar having special processing modifications in an image-formation processor to receive an echo from a remote transponder, after the transponder receives and retransmits the SAR illuminations, and to enhance tile transponder`s echo relative to surrounding ground clutter by recognizing special transponder modulations from phase-shifted from the transponder retransmissions. The remote radio-frequency tag also transmits information to the SAR through a single antenna that also serves to receive the SAR illuminations. Unique tag-modulation and SAR signal processing techniques, in combination, allow the detection and precise geographical location of the tag, through the reduction of interfering signals from ground clutter, and allow communication of environmental and status information from said tag to be communicated to said SAR.

  12. Radar transponder apparatus and signal processing technique

    DOEpatents

    Axline, Jr., Robert M.; Sloan, George R.; Spalding, Richard E.

    1996-01-01

    An active, phase-coded, time-grating transponder and a synthetic-aperture radar (SAR) and signal processor means, in combination, allow the recognition and location of the transponder (tag) in the SAR image and allow communication of information messages from the transponder to the SAR. The SAR is an illuminating radar having special processing modifications in an image-formation processor to receive an echo from a remote transponder, after the transponder receives and retransmits the SAR illuminations, and to enhance the transponder's echo relative to surrounding ground clutter by recognizing special transponder modulations from phase-shifted from the transponder retransmissions. The remote radio-frequency tag also transmits information to the SAR through a single antenna that also serves to receive the SAR illuminations. Unique tag-modulation and SAR signal processing techniques, in combination, allow the detection and precise geographical location of the tag through the reduction of interfering signals from ground clutter, and allow communication of environmental and status information from said tag to be communicated to said SAR.

  13. Radar transponder apparatus and signal processing technique

    DOEpatents

    Axline, R.M. Jr.; Sloan, G.R.; Spalding, R.E.

    1996-01-23

    An active, phase-coded, time-grating transponder and a synthetic-aperture radar (SAR) and signal processor means, in combination, allow the recognition and location of the transponder (tag) in the SAR image and allow communication of information messages from the transponder to the SAR. The SAR is an illuminating radar having special processing modifications in an image-formation processor to receive an echo from a remote transponder, after the transponder receives and retransmits the SAR illuminations, and to enhance the transponder`s echo relative to surrounding ground clutter by recognizing special transponder modulations from phase-shifted from the transponder retransmissions. The remote radio-frequency tag also transmits information to the SAR through a single antenna that also serves to receive the SAR illuminations. Unique tag-modulation and SAR signal processing techniques, in combination, allow the detection and precise geographical location of the tag through the reduction of interfering signals from ground clutter, and allow communication of environmental and status information from said tag to be communicated to said SAR. 4 figs.

  14. SEMICONDUCTOR INTEGRATED CIRCUITS: A monolithic 3.1-4.8 GHz MB-OFDM UWB transceiver in 0.18-μm CMOS

    NASA Astrophysics Data System (ADS)

    Renliang, Zheng; Xudong, Jiang; Wang, Yao; Guang, Yang; Jiangwei, Yin; Jianqin, Zheng; Junyan, Ren; Wei, Li; Ning, Li

    2010-06-01

    A monolithic RF transceiver for an MB-OFDM UWB system in 3.1-4.8 GHz is presented. The transceiver adopts direct-conversion architecture and integrates all building blocks including a gain controllable wideband LNA, a I/Q merged quadrature mixer, a fifth-order Gm-C bi-quad Chebyshev LPF/VGA, a fast-settling frequency synthesizer with a poly-phase filter, a linear broadband up-conversion quadrature modulator, an active D2S converter and a variable-gain power amplifier. The ESD protected transceiver is fabricated in Jazz Semiconductor's 0.18-μm RF CMOS with an area of 6.1 mm2 and draws a total current of 221 mA from 1.8-V supply. The receiver achieves a maximum voltage gain of 68 dB with a control range of 42 dB in 6 dB/step, noise figures of 5.5-8.8 dB for three sub-bands, and an in-band/out-band IIP3 better than -4 dBm/+9 dBm. The transmitter achieves an output power ranging from -10.7 to -3 dBm with gain control, an output P1dB better than -7.7 dBm, a sideband rejection about 32.4 dBc, and LO suppression of 31.1 dBc. The hopping time among sub-bands is less than 2.05 ns.

  15. Hybrid graphene-copper UWB array sensor for brain tumor detection via scattering parameters in microwave detection system

    NASA Astrophysics Data System (ADS)

    Jamlos, Mohd Aminudin; Ismail, Abdul Hafiizh; Jamlos, Mohd Faizal; Narbudowicz, Adam

    2017-01-01

    Hybrid graphene-copper ultra-wideband array sensor applied to microwave imaging technique is successfully used in detecting and visualizing tumor inside human brain. The sensor made of graphene coated film for the patch while copper for both the transmission line and parasitic element. The hybrid sensor performance is better than fully copper sensor. Hybrid sensor recorded wider bandwidth of 2.0-10.1 GHz compared with fully copper sensor operated from 2.5 to 10.1 GHz. Higher gain of 3.8-8.5 dB is presented by hybrid sensor, while fully copper sensor stated lower gain ranging from 2.6 to 6.7 dB. Both sensors recorded excellent total efficiency averaged at 97 and 94%, respectively. The sensor used for both transmits equivalent signal and receives backscattering signal from stratified human head model in detecting tumor. Difference in the data of the scattering parameters recorded from the head model with presence and absence of tumor is used as the main data to be further processed in confocal microwave imaging algorithm in generating image. MATLAB software is utilized to analyze S-parameter signals obtained from measurement. Tumor presence is indicated by lower S-parameter values compared to higher values recorded by tumor absence.

  16. Advanced signal processing method for ground penetrating radar feature detection and enhancement

    NASA Astrophysics Data System (ADS)

    Zhang, Yu; Venkatachalam, Anbu Selvam; Huston, Dryver; Xia, Tian

    2014-03-01

    This paper focuses on new signal processing algorithms customized for an air coupled Ultra-Wideband (UWB) Ground Penetrating Radar (GPR) system targeting highway pavements and bridge deck inspections. The GPR hardware consists of a high-voltage pulse generator, a high speed 8 GSps real time data acquisition unit, and a customized field-programmable gate array (FPGA) control element. In comparison to most existing GPR system with low survey speeds, this system can survey at normal highway speed (60 mph) with a high horizontal resolution of up to 10 scans per centimeter. Due to the complexity and uncertainty of subsurface media, the GPR signal processing is important but challenging. In this GPR system, an adaptive GPR signal processing algorithm using Curvelet Transform, 2D high pass filtering and exponential scaling is proposed to alleviate noise and clutter while the subsurface features are preserved and enhanced. First, Curvelet Transform is used to remove the environmental and systematic noises while maintain the range resolution of the B-Scan image. Then, mathematical models for cylinder-shaped object and clutter are built. A two-dimension (2D) filter based on these models removes clutter and enhances the hyperbola feature in a B-Scan image. Finally, an exponential scaling method is applied to compensate the signal attenuation in subsurface materials and to improve the desired signal feature. For performance test and validation, rebar detection experiments and subsurface feature inspection in laboratory and field configurations are performed.

  17. Remote Monitoring and Tracking of UF6 Cylinders Using Long-Range Passive Ultra-wideband (UWB) RFID Tags

    SciTech Connect

    Nekoogar, F; Dowla, F

    2007-06-06

    An IAEA Technical Meeting on Techniques for IAEA Verification of Enrichment Activities identified 'smart tags' as a technology that should be assessed for tracking and locating UF6 cylinders. Although there is vast commercial industry working on RFID systems, the vulnerabilities of commercial products are only beginning to emerge. Most of the commercially off-the-shelf (COTS) RFID systems operate in very narrow frequency bands, making them vulnerable to detection, jamming and tampering and also presenting difficulties when used around metals (i.e. UF6 cylinders). Commercial passive RFID tags have short range, while active RFID tags that provide long ranges have limited lifetimes. There are also some concerns with the introduction of strong (narrowband) radio frequency signals around radioactive and nuclear materials. Considering the shortcomings of commercial RFID systems, in their current form, they do not offer a promising solution for continuous monitoring and tracking of UF6 cylinders. In this paper, we identify the key challenges faced by commercial RFID systems for monitoring UF6 cylinders, and introduce an ultra-wideband approach for tag/reader communications that addresses most of the identified challenges for IAEA safeguards applications.

  18. Few millimeter-resolution Brillouin optical correlation domain analysis using amplified-spontaneous-emission pump and signal waves

    NASA Astrophysics Data System (ADS)

    Cohen, Raphael; London, Yosef; Antman, Yair; Zadok, Avi

    2014-05-01

    A new technique for Brillouin optical correlation domain analysis is proposed and demonstrated, in which the pump and signal waves are drawn from the filtered amplified spontaneous emission of an erbium-doped fiber amplifier. An estimated spatial resolution of 3.3 mm is obtained using a 33 GHz-wide source. The reconstruction of the Brillouin gain line and the recognition of a localized hot spot are demonstrated in a proof-of-concept experiment. Unlike phase-coded correlation domain analysis methods, the proposed scheme is not restricted by the bandwidth of available electro-optic modulators or pattern generators. Resolution is scalable to less than one millimeter.

  19. Signaling aggression.

    PubMed

    van Staaden, Moira J; Searcy, William A; Hanlon, Roger T

    2011-01-01

    From psychological and sociological standpoints, aggression is regarded as intentional behavior aimed at inflicting pain and manifested by hostility and attacking behaviors. In contrast, biologists define aggression as behavior associated with attack or escalation toward attack, omitting any stipulation about intentions and goals. Certain animal signals are strongly associated with escalation toward attack and have the same function as physical attack in intimidating opponents and winning contests, and ethologists therefore consider them an integral part of aggressive behavior. Aggressive signals have been molded by evolution to make them ever more effective in mediating interactions between the contestants. Early theoretical analyses of aggressive signaling suggested that signals could never be honest about fighting ability or aggressive intentions because weak individuals would exaggerate such signals whenever they were effective in influencing the behavior of opponents. More recent game theory models, however, demonstrate that given the right costs and constraints, aggressive signals are both reliable about strength and intentions and effective in influencing contest outcomes. Here, we review the role of signaling in lieu of physical violence, considering threat displays from an ethological perspective as an adaptive outcome of evolutionary selection pressures. Fighting prowess is conveyed by performance signals whose production is constrained by physical ability and thus limited to just some individuals, whereas aggressive intent is encoded in strategic signals that all signalers are able to produce. We illustrate recent advances in the study of aggressive signaling with case studies of charismatic taxa that employ a range of sensory modalities, viz. visual and chemical signaling in cephalopod behavior, and indicators of aggressive intent in the territorial calls of songbirds.

  20. Signals of opportunity assisted ubiquitous geolocation and navigation technology

    NASA Astrophysics Data System (ADS)

    Tian, Hui; Mok, Esmond; Xia, Linyuan; Wu, Zhongyi

    2008-10-01

    The desire of geolocation and navigation technologies that provide precise, fast and reliable geo-services has exploded in the recent years, and there is a dramatic increase in the geo-service market varies from mass market applications to the new and innovative applications. The lack of reliable GNSS signals in the NLOS environment confronts many innovative ideas related to mass market location-based applications. But there is an optimized way to provide the ubiquitous geolocation services via exploitation of signals of opportunity (SoOP). The core concept of ubiquitous geolocation and navigation is provide globally available geo-services by giving the mobile terminal the ability to acquire their location information, this technology can be applied at all scales geo-reference by sharing some simple, inexpensive, robust geolocation and navigation algorisms for different technology such as GNSS and other emerging technology, and the goals of the ubiquitous geolocation and navigation service are reliable availability, transparency, seamlessness, awareness, and trustworthiness. SoOP are primarily envisioned to be man-made radio emitters not originally intended for geolocation and navigation, but may be extended to active beacons purposely deployed in an emergency situation, in this paper, we also regarded the signals of different wireless network those defined by the IEEE 802.11, IEEE 802.15 and IEEE 802.16 as an important part of SoOP. The use of widely available, powerful, and economically important SoOP in Hong Kong will provide a robust geolocation and navigation capability. We made some initial investigation into the use of the SoOP through feasibility studies and prototype investigations of the use of wireless local area network (WLAN), ultra-wide band (UWB) and ZigBee.

  1. Wireless Data Acquisition of Transient Signals for Mobile Spectrometry Applications.

    PubMed

    Trzcinski, Peter; Weagant, Scott; Karanassios, Vassili

    2016-05-01

    Wireless data acquisition using smartphones or handhelds offers increased mobility, it provides reduced size and weight, it has low electrical power requirements, and (in some cases) it has an ability to access the internet. Thus, it is well suited for mobile spectrometry applications using miniaturized, field-portable spectrometers, or detectors for chemical analysis in the field (i.e., on-site). There are four main wireless communications standards that can be used for wireless data acquisition, namely ZigBee, Bluetooth, Wi-Fi, and UWB (ultra-wide band). These are briefly reviewed and are evaluated for applicability to data acquisition of transient signals (i.e., time-domain) in the field (i.e., on-site) from a miniaturized, field-portable photomultiplier tube detector and from a photodiode array detector installed in a miniaturized, field-portable fiber optic spectrometer. These are two of the most widely used detectors for optical measurements in the ultraviolet-visible range of the spectrum. A miniaturized, 3D-printed, battery-operated microplasma-on-a-chip was used for generation of transient optical emission signals. Elemental analysis from liquid microsamples, a microplasma, and a handheld or a smartphone will be used as examples. Development and potential applicability of wireless data acquisition of transient optical emission signals for taking part of the lab to the sample types of mobile, field-portable spectrometry applications will be discussed. The examples presented are drawn from past and ongoing work in the authors' laboratory. A handheld or a smartphone were used as the mobile computing devices of choice. © The Author(s) 2016.

  2. Conversion of a phase- to a rate-coded position signal by a three-stage model of theta cells, grid cells, and place cells.

    PubMed

    Blair, Hugh T; Gupta, Kishan; Zhang, Kechen

    2008-01-01

    As a rat navigates through a familiar environment, its position in space is encoded by firing rates of place cells and grid cells. Oscillatory interference models propose that this positional firing rate code is derived from a phase code, which stores the rat's position as a pattern of phase angles between velocity-modulated theta oscillations. Here we describe a three-stage network model, which formalizes the computational steps that are necessary for converting phase-coded position signals (represented by theta oscillations) into rate-coded position signals (represented by grid cells and place cells). The first stage of the model proposes that the phase-coded position signal is stored and updated by a bank of ring attractors, like those that have previously been hypothesized to perform angular path integration in the head-direction cell system. We show analytically how ring attractors can serve as central pattern generators for producing velocity-modulated theta oscillations, and we propose that such ring attractors may reside in subcortical areas where hippocampal theta rhythm is known to originate. In the second stage of the model, grid fields are formed by oscillatory interference between theta cells residing in different (but not the same) ring attractors. The model's third stage assumes that hippocampal neurons generate Gaussian place fields by computing weighted sums of inputs from a basis set of many grid fields. Here we show that under this assumption, the spatial frequency spectrum of the Gaussian place field defines the vertex spacings of grid cells that must provide input to the place cell. This analysis generates a testable prediction that grid cells with large vertex spacings should send projections to the entire hippocampus, whereas grid cells with smaller vertex spacings may project more selectively to the dorsal hippocampus, where place fields are smallest.

  3. A two-phase code for protoplanetary disks

    NASA Astrophysics Data System (ADS)

    Inaba, S.; Barge, P.; Daniel, E.; Guillard, H.

    2005-02-01

    A high accuracy 2D hydrodynamical code has been developed to simulate the flow of gas and solid particles in protoplanetary disks. Gas is considered as a compressible fluid while solid particles, fully coupled to the gas by aerodynamical forces, are treated as a pressure-free diluted second phase. The solid particles lose energy and angular momentum which are transfered to the gas. As a result particles migrate inward toward the star and gas moves outward. High accuracy is necessary to account for the coupling. Boundary conditions must account for the inward/outward motions of the two phases. The code has been tested on one and two dimensional situations. The numerical results were compared with analytical solutions in three different cases: i) the disk is composed of a single gas component; ii) solid particles migrate in a steady flow of gas; iii) gas and solid particles evolve simultaneously. The code can easily reproduce known analytical solutions and is a powerful tool to study planetary formation at the decoupling stage. For example, the evolution of an over-density in the radial distribution of solids is found to differ significantly from the case where no back reaction of the particles onto the gas is assumed. Inside the bump, solid particles have a drift velocity approximately 16 times smaller than outside which significantly increases the residence time of the particles in the nebula. This opens some interesting perspectives to solve the timescale problem for the formation of planetesimals.

  4. Phase-Coding Self-Testing Quantum Random Number Generator

    NASA Astrophysics Data System (ADS)

    Song, Xiao-Tian; Li, Hong-Wei; Yin, Zhen-Qiang; Liang, Wen-Ye; Zhang, Chun-Mei; Han, Yun-Guang; Chen, Wei; Han, Zheng-Fu

    2015-08-01

    Not Available Supported by the National Basic Research Program of China under Grant Nos 2011CBA00200 and 2011CB921200, the National Natural Science Foundation of China under Grant Nos 61201239, 61205118, 11304397 and 61475148, and the Strategic Priority Research Program (B) of Chinese Academy of Sciences under Grant Nos XDB01030100 and XDB01030300.

  5. Signal processing

    NASA Astrophysics Data System (ADS)

    Norman, David M.

    The application of signal processing technology to conventional weapons systems can lower operator workloads and enhance kill probabilities, while automating wide-area surveillance, target search and classification, target tracking, and aimpoint selection. Immediate opportunities exist for automatic target cueing in underwater and over-the-horizon targeting, as well as for airborne multiple-target fire control. By embedding the transit/receive electronics into conformal aircraft sensor arrays, a 'smart' skin can be created. Electronically scanned phased arrays can be used to yield accurate azimuthal and elevation positions while nullifying EW threats. Attention is given to major development thrusts in algorithm design.

  6. Signal Processing

    DTIC Science & Technology

    1989-03-01

    ORGANIZATION Univ of Minnesota (f*fto U. S. Army Research Office 6c. ADDRESS (City, State, and ZIP Code) 7b. ADDRESS (Wiy Stat, and ZIP Code...Minneapolis, MN 55455 P. 0. Box 12211 Research Triangle Park, NC 27709-2211 Sa. NAME Of FUNDING ISPONSORING Sb. OFFICE SYMBOL 9. PROCUREMENT INSTRUMENT...PROJECT ITASK jWORK UNIT Research Triangle Park, NC 27709-2211 EMNTO.I NO NO CESOIO 11. TITLE (Incudt Security Classifiratio") Signal Processing of, he auth

  7. Analyses and Measures of GPR Signal with Superimposed Noise

    NASA Astrophysics Data System (ADS)

    Chicarella, Simone; Ferrara, Vincenzo; D'Atanasio, Paolo; Frezza, Fabrizio; Pajewski, Lara; Pavoncello, Settimio; Prontera, Santo; Tedeschi, Nicola; Zambotti, Alessandro

    2014-05-01

    The influence of EM noises and environmental hard conditions on the GPR surveys has been examined analytically [1]. In the case of pulse radar GPR, many unwanted signals as stationary clutter, non-stationary clutter, random noise, and time jitter, influence the measurement signal. When GPR is motionless, stationary clutter is the most dominant signal component due to the reflections of static objects different from the investigated target, and to the direct antenna coupling. Moving objects like e.g. persons and vehicles, and the swaying of tree crown, produce non-stationary clutter. Device internal noise and narrowband jamming are e.g. two potential sources of random noises. Finally, trigger instabilities generate random jitter. In order to estimate the effective influence of these noise signal components, we organized some experimental setup of measurement. At first, we evaluated for the case of a GPR basic detection, simpler image processing of radargram. In the future, we foresee experimental measurements for detection of the Doppler frequency changes induced by movements of targets (like physiological movements of survivors under debris). We obtain image processing of radargram by using of GSSI SIR® 2000 GPR system together with the UWB UHF GPR-antenna (SUB-ECHO HBD 300, a model manufactured by Radarteam company). Our work includes both characterization of GPR signal without (or almost without) a superimposed noise, and the effect of jamming originated from the coexistence of a different radio signal. For characterizing GPR signal, we organized a measurement setup that includes the following instruments: mod. FSP 30 spectrum analyser by Rohde & Schwarz which operates in the frequency range 9 KHz - 30 GHz, mod. Sucoflex 104 cable by Huber Suhner (10 MHz - 18 GHz), and HL050 antenna by Rohde & Schwarz (bandwidth: from 850 MHz to 26.5 GHz). The next analysis of superimposed jamming will examine two different signal sources: by a cellular phone and by a

  8. Urothelial Signaling

    PubMed Central

    Andersson, Karl-Erik

    2013-01-01

    The urothelium, which lines the inner surface of the renal pelvis, the ureters, and the urinary bladder, not only forms a high-resistance barrier to ion, solute and water flux, and pathogens, but also functions as an integral part of a sensory web which receives, amplifies, and transmits information about its external milieu. Urothelial cells have the ability to sense changes in their extracellular environment, and respond to chemical, mechanical and thermal stimuli by releasing various factors such as ATP, nitric oxide, and acetylcholine. They express a variety of receptors and ion channels, including P2X3 purinergic receptors, nicotinic and muscarinic receptors, and TRP channels, which all have been implicated in urothelial-neuronal interactions, and involved in signals that via components in the underlying lamina propria, such as interstitial cells, can be amplified and conveyed to nerves, detrusor muscle cells, and ultimately the central nervous system. The specialized anatomy of the urothelium and underlying structures, and the possible communication mechanisms from urothelial cells to various cell types within the bladder wall are described. Changes in the urothelium/lamina propria (“mucosa”) produced by different bladder disorders are discussed, as well as the mucosa as a target for therapeutic interventions. PMID:23589830

  9. Signal processing techniques for the U.S. Army Research Laboratory stepped frequency ultra-wideband radar

    NASA Astrophysics Data System (ADS)

    Nguyen, Lam

    2017-05-01

    The U.S. Army Research Laboratory (ARL) recently designed and tested a new prototype radar, the Spectrally Agile Frequency-Incrementing Reconfigurable (SAFIRE) radar system, based on a stepped-frequency architecture to address issues associated with our previous impulse-based radars. This is a low-frequency ultra-wideband (UWB) radar with frequencies spanning from 300 to 2000 MHz. Mounted on a vehicle, the radar can be configured in either sidelooking or forward-looking synthetic aperture radar (SAR) mode. We recently conducted our first experiment at Yuma Proving Grounds (YPG). This paper summarizes the radar configurations, parameters, and SAR geometry. The radar data and other noise sources, to include the self-interference signals and radio-frequency interference (RFI) noise sources, are presented and characterized in both the raw (pre-focus) and SAR imagery domains. This paper also describes our signal processing techniques for extracting noise from radar data, as well as the SAR imaging algorithms for forming SAR imagery in both forward- and side-looking modes. Finally, this paper demonstrates our spectral recovery technique and results for a radar operating in a spectrally restricted environment.

  10. Scram signal generator

    DOEpatents

    Johanson, E.W.; Simms, R.

    A scram signal generating circuit for nuclear reactor installations monitors a flow signal representing the flow rate of the liquid sodium coolant which is circulated through the reactor, and initiates reactor shutdown for a rapid variation in the flow signal, indicative of fuel motion. The scram signal generating circuit includes a long-term drift compensation circuit which processes the flow signal and generates an output signal representing the flow rate of the coolant. The output signal remains substantially unchanged for small variations in the flow signal, attributable to long term drift in the flow rate, but a rapid change in the flow signal, indicative of a fast flow variation, causes a corresponding change in the output signal. A comparator circuit compares the output signal with a reference signal, representing a given percentage of the steady state flow rate of the coolant, and generates a scram signal to initiate reactor shutdown when the output signal equals the reference signal.

  11. Scram signal generator

    DOEpatents

    Johanson, Edward W.; Simms, Richard

    1981-01-01

    A scram signal generating circuit for nuclear reactor installations monitors a flow signal representing the flow rate of the liquid sodium coolant which is circulated through the reactor, and initiates reactor shutdown for a rapid variation in the flow signal, indicative of fuel motion. The scram signal generating circuit includes a long-term drift compensation circuit which processes the flow signal and generates an output signal representing the flow rate of the coolant. The output signal remains substantially unchanged for small variations in the flow signal, attributable to long term drift in the flow rate, but a rapid change in the flow signal, indicative of a fast flow variation, causes a corresponding change in the output signal. A comparator circuit compares the output signal with a reference signal, representing a given percentage of the steady state flow rate of the coolant, and generates a scram signal to initiate reactor shutdown when the output signal equals the reference signal.

  12. SEMICONDUCTOR INTEGRATED CIRCUITS: A 3.1-4.8 GHz transmitter with a high frequency divider in 0.18 μm CMOS for OFDM-UWB

    NASA Astrophysics Data System (ADS)

    Renliang, Zheng; Junyan, Ren; Wei, Li; Ning, Li

    2009-12-01

    A fully integrated low power RF transmitter for a WiMedia 3.1-4.8 GHz multiband orthogonal frequency division multiplexing ultra-wideband system is presented. With a separate transconductance stage, the quadrature up-conversion modulator achieves high linearity with low supply voltage. The co-design of different resonant frequencies of the modulator and the differential to single (D2S) converter ensures in-band gain flatness. By means of a series inductor peaking technique, the D2S converter obtains 9 dB more gain without extra power consumption. A divided-by-2 divider is used for carrier signal generation. The measurement results show an output power between -10.7 and -3.1 dBm with 7.6 dB control range, an OIP3 up to 12 dBm, a sideband rejection of 35 dBc and a carrier rejection of 30 dBc. The ESD protected chip is fabricated in the Jazz 0.18 μm RF CMOS process with an area of 1.74 mm2 and only consumes 32 mA current (at 1.8 V) including the test associated parts.

  13. Signal processor for processing ultrasonic receiver signals

    DOEpatents

    Fasching, George E.

    1980-01-01

    A signal processor is provided which uses an analog integrating circuit in conjunction with a set of digital counters controlled by a precision clock for sampling timing to provide an improved presentation of an ultrasonic transmitter/receiver signal. The signal is sampled relative to the transmitter trigger signal timing at precise times, the selected number of samples are integrated and the integrated samples are transferred and held for recording on a strip chart recorder or converted to digital form for storage. By integrating multiple samples taken at precisely the same time with respect to the trigger for the ultrasonic transmitter, random noise, which is contained in the ultrasonic receiver signal, is reduced relative to the desired useful signal.

  14. Signal verification can promote reliable signalling

    PubMed Central

    Broom, Mark; Ruxton, Graeme D.; Schaefer, H. Martin

    2013-01-01

    The central question in communication theory is whether communication is reliable, and if so, which mechanisms select for reliability. The primary approach in the past has been to attribute reliability to strategic costs associated with signalling as predicted by the handicap principle. Yet, reliability can arise through other mechanisms, such as signal verification; but the theoretical understanding of such mechanisms has received relatively little attention. Here, we model whether verification can lead to reliability in repeated interactions that typically characterize mutualisms. Specifically, we model whether fruit consumers that discriminate among poor- and good-quality fruits within a population can select for reliable fruit signals. In our model, plants either signal or they do not; costs associated with signalling are fixed and independent of plant quality. We find parameter combinations where discriminating fruit consumers can select for signal reliability by abandoning unprofitable plants more quickly. This self-serving behaviour imposes costs upon plants as a by-product, rendering it unprofitable for unrewarding plants to signal. Thus, strategic costs to signalling are not a prerequisite for reliable communication. We expect verification to more generally explain signal reliability in repeated consumer–resource interactions that typify mutualisms but also in antagonistic interactions such as mimicry and aposematism. PMID:24068354

  15. Retroactive Signaling in Short Signaling Pathways

    PubMed Central

    Sepulchre, Jacques-Alexandre; Merajver, Sofía D.; Ventura, Alejandra C.

    2012-01-01

    In biochemical signaling pathways without explicit feedback connections, the core signal transduction is usually described as a one-way communication, going from upstream to downstream in a feedforward chain or network of covalent modification cycles. In this paper we explore the possibility of a new type of signaling called retroactive signaling, offered by the recently demonstrated property of retroactivity in signaling cascades. The possibility of retroactive signaling is analysed in the simplest case of the stationary states of a bicyclic cascade of signaling cycles. In this case, we work out the conditions for which variables of the upstream cycle are affected by a change of the total amount of protein in the downstream cycle, or by a variation of the phosphatase deactivating the same protein. Particularly, we predict the characteristic ranges of the downstream protein, or of the downstream phosphatase, for which a retroactive effect can be observed on the upstream cycle variables. Next, we extend the possibility of retroactive signaling in short but nonlinear signaling pathways involving a few covalent modification cycles. PMID:22848403

  16. Ultra-Wideband Signals for Target Detection in Foliage

    DTIC Science & Technology

    2007-11-02

    1997], and Fourier analysis [ Papoulis , 1987]. This approach gives a simple intuitive physical explanation for the formation and propagation of...transform or Fast Fourier Transform (FFT) techniques can be applied to compute (2.14) and (2.15) [ Papoulis , 1987; Oppenheim et al., 1997] to obtain the...Assessment of Ultra-Wideband (UWB) Technology, Battelle Tactical Technology Center, July 13, 1990. A. Papoulis , The Fourier Integral and its

  17. Multidimensional signal processing for ultrasonic signal classification

    NASA Astrophysics Data System (ADS)

    Kim, J.; Ramuhalli, P.; Udpa, L.; Udpa, S.

    2001-04-01

    Neural network based signal classification systems are being used increasingly in the analysis of large volumes of data obtained in NDE applications. One example is in the interpretation on ultrasonic signals obtained from inspection of welds where signals can be due to porosity, slag, lack of fusion and cracks in the weld region. Standard techniques rely on differences in individual A-scans to classify the signals. This paper proposes an ultrasonic signal classification technique based on the information in a group of signals and examining the statistical characteristics of the signals. The method was 2-dimensional signal processing algorithms to analyze the information in B- and B'-scan images. In this paper, 2-dimensional transform based coefficients of the images are used as features and a multilayer perceptron is used to classify them. These results are then combined to get the final classification for the inspected region. Results of applying the technique to data obtained from the inspection of welds are presented.

  18. ERK Signals: Scaffolding Scaffolds?

    PubMed Central

    Casar, Berta; Crespo, Piero

    2016-01-01

    ERK1/2 MAP Kinases become activated in response to multiple intra- and extra-cellular stimuli through a signaling module composed of sequential tiers of cytoplasmic kinases. Scaffold proteins regulate ERK signals by connecting the different components of the module into a multi-enzymatic complex by which signal amplitude and duration are fine-tuned, and also provide signal fidelity by isolating this complex from external interferences. In addition, scaffold proteins play a central role as spatial regulators of ERKs signals. In this respect, depending on the subcellular localization from which the activating signals emanate, defined scaffolds specify which substrates are amenable to be phosphorylated. Recent evidence has unveiled direct interactions among different scaffold protein species. These scaffold-scaffold macro-complexes could constitute an additional level of regulation for ERK signals and may serve as nodes for the integration of incoming signals and the subsequent diversification of the outgoing signals with respect to substrate engagement. PMID:27303664

  19. A Novel Approach to Photonic Generation and Modulation of Ultra-Wideband Pulses

    NASA Astrophysics Data System (ADS)

    Xiang, Peng; Guo, Hao; Chen, Dalei; Zhu, Huatao

    2016-01-01

    A novel approach to photonic generation of ultra-wideband (UWB) signals is proposed in this paper. The proposed signal generator is capable of generating UWB doublet pulses with flexible reconfigurability, and many different pulse modulation formats, including the commonly used pulse-position modulation (PPM) and bi-phase modulation (BPM) can be realized. Moreover, the photonic UWB pulse generator is capable of generating UWB signals with a tunable spectral notch-band, which is desirable to realize the interference avoidance between UWB and other narrow band systems, such as Wi-Fi. A mathematical model describing the proposed system is developed and the generation of UWB signals with different modulation formats is demonstrated via computer simulations.

  20. Signaling in myxobacteria.

    PubMed

    Kaiser, Dale

    2004-01-01

    Myxobacteria use soluble and cell-contact signals during their starvation-induced formation of fruiting bodies. These signals coordinate developmental gene expression with the cell movements that build fruiting bodies. Early in development, the quorum-sensing A-signal in Myxococcus xanthus helps to assess starvation and induce the first stage of aggregation. Later, the morphogenetic C-signal helps to pattern cell movement and shape the fruiting body. C-signal is a 17-kDa cell surface protein that signals by contact between the ends of two cells. The number of C-signal molecules per cell rises 100-fold from the beginning of fruiting body development to the end, when spores are formed. Traveling waves, streams, and sporulation have increasing thresholds for C-signal activity, and this progression ensures that spores form inside fruiting bodies.

  1. Signal sciences workshop proceedings

    SciTech Connect

    Candy, J.V.

    1997-05-01

    This meeting is aimed primarily at signal processing and controls. The technical program for the 1997 Workshop includes a variety of efforts in the Signal Sciences with applications in the Microtechnology Area a new program at LLNL and a future area of application for both Signal/Image Sciences. Special sessions organized by various individuals in Seismic and Optical Signal Processing as well as Micro-Impulse Radar Processing highlight the program, while the speakers at the Signal Processing Applications session discuss various applications of signal processing/control to real world problems. For the more theoretical, a session on Signal Processing Algorithms was organized as well as for the more pragmatic, featuring a session on Real-Time Signal Processing.

  2. Tetrapyrrole Signaling in Plants

    PubMed Central

    Larkin, Robert M.

    2016-01-01

    Tetrapyrroles make critical contributions to a number of important processes in diverse organisms. In plants, tetrapyrroles are essential for light signaling, the detoxification of reactive oxygen species, the assimilation of nitrate and sulfate, respiration, photosynthesis, and programed cell death. The misregulation of tetrapyrrole metabolism can produce toxic reactive oxygen species. Thus, it is not surprising that tetrapyrrole metabolism is strictly regulated and that tetrapyrrole metabolism affects signaling mechanisms that regulate gene expression. In plants and algae, tetrapyrroles are synthesized in plastids and were some of the first plastid signals demonstrated to regulate nuclear gene expression. In plants, the mechanism of tetrapyrrole-dependent plastid-to-nucleus signaling remains poorly understood. Additionally, some of experiments that tested ideas for possible signaling mechanisms appeared to produce conflicting data. In some instances, these conflicts are potentially explained by different experimental conditions. Although the biological function of tetrapyrrole signaling is poorly understood, there is compelling evidence that this signaling is significant. Specifically, this signaling appears to affect the accumulation of starch and may promote abiotic stress tolerance. Tetrapyrrole-dependent plastid-to-nucleus signaling interacts with a distinct plastid-to-nucleus signaling mechanism that depends on GENOMES UNCUOPLED1 (GUN1). GUN1 contributes to a variety of processes, such as chloroplast biogenesis, the circadian rhythm, abiotic stress tolerance, and development. Thus, the contribution of tetrapyrrole signaling to plant function is potentially broader than we currently appreciate. In this review, I discuss these aspects of tetrapyrrole signaling. PMID:27807442

  3. Signal Processing, Analysis, & Display

    SciTech Connect

    Lager, Darrell; Azevado, Stephen

    1986-06-01

    SIG is a general-purpose signal processing, analysis, and display program. Its main purpose is to perform manipulations on time- and frequency-domain signals. However, it has been designed to ultimately accommodate other representations for data such as multiplexed signals and complex matrices. Two user interfaces are provided in SIG - a menu mode for the unfamiliar user and a command mode for more experienced users. In both modes errors are detected as early as possible and are indicated by friendly, meaningful messages. An on-line HELP package is also included. A variety of operations can be performed on time- and frequency-domain signals including operations on the samples of a signal, operations on the entire signal, and operations on two or more signals. Signal processing operations that can be performed are digital filtering (median, Bessel, Butterworth, and Chebychev), ensemble average, resample, auto and cross spectral density, transfer function and impulse response, trend removal, convolution, Fourier transform and inverse window functions (Hamming, Kaiser-Bessel), simulation (ramp, sine, pulsetrain, random), and read/write signals. User definable signal processing algorithms are also featured. SIG has many options including multiple commands per line, command files with arguments,commenting lines, defining commands, and automatic execution for each item in a repeat sequence. Graphical operations on signals and spectra include: x-y plots of time signals; real, imaginary, magnitude, and phase plots of spectra; scaling of spectra for continuous or discrete domain; cursor zoom; families of curves; and multiple viewports.

  4. Satellite signaling at synapses

    PubMed Central

    O'Connor-Giles, Kate M.; Ganetzky, Barry

    2013-01-01

    Neural function requires effective communication between neurons and their targets at synapses. Thus, proper formation, growth and plasticity of synapses are critical to behavior. A retrograde (muscle to neuron) BMP signal is required to promote synaptic growth, homeostasis and stability at Drosophila neuromuscular junctions (NMJs).1-4 We recently demonstrated that this signal constitutes an instructive signal that sculpts synaptic growth in a graded manner and uncovered a presynaptic endocytic mechanism that modulates BMP signaling levels. In the absence of this regulation, excessive BMP signaling results in overgrown NMJs with a proliferation of ectopic boutons.5 PMID:20798607

  5. Acoustic Signal Processing

    NASA Astrophysics Data System (ADS)

    Hartmann, William M.; Candy, James V.

    Signal processing refers to the acquisition, storage, display, and generation of signals - also to the extraction of information from signals and the re-encoding of information. As such, signal processing in some form is an essential element in the practice of all aspects of acoustics. Signal processing algorithms enable acousticians to separate signals from noise, to perform automatic speech recognition, or to compress information for more efficient storage or transmission. Signal processing concepts are the building blocks used to construct models of speech and hearing. Now, in the 21st century, all signal processing is effectively digital signal processing. Widespread access to high-speed processing, massive memory, and inexpensive software make signal processing procedures of enormous sophistication and power available to anyone who wants to use them. Because advanced signal processing is now accessible to everybody, there is a need for primers that introduce basic mathematical concepts that underlie the digital algorithms. The present handbook chapter is intended to serve such a purpose.

  6. Neuronal signaling through endocytosis.

    PubMed

    Cosker, Katharina E; Segal, Rosalind A

    2014-02-01

    The distinctive morphology of neurons, with complex dendritic arbors and extensive axons, presents spatial challenges for intracellular signal transduction. The endosomal system provides mechanisms that enable signaling molecules initiated by extracellular cues to be trafficked throughout the expanse of the neuron, allowing intracellular signals to be sustained over long distances. Therefore endosomes are critical for many aspects of neuronal signaling that regulate cell survival, axonal growth and guidance, dendritic branching, and cell migration. An intriguing characteristic of neuronal signal transduction is that endosomal trafficking enables physiological responses that vary based on the subcellular location of signal initiation. In this review, we will discuss the specialized mechanisms and the functional significance of endosomal signaling in neurons, both during normal development and in disease.

  7. Neuronal Signaling through Endocytosis

    PubMed Central

    Cosker, Katharina E.; Segal, Rosalind A.

    2014-01-01

    The distinctive morphology of neurons, with complex dendritic arbors and extensive axons, presents spatial challenges for intracellular signal transduction. The endosomal system provides mechanisms that enable signaling molecules initiated by extracellular cues to be trafficked throughout the expanse of the neuron, allowing intracellular signals to be sustained over long distances. Therefore endosomes are critical for many aspects of neuronal signaling that regulate cell survival, axonal growth and guidance, dendritic branching, and cell migration. An intriguing characteristic of neuronal signal transduction is that endosomal trafficking enables physiological responses that vary based on the subcellular location of signal initiation. In this review, we will discuss the specialized mechanisms and the functional significance of endosomal signaling in neurons, both during normal development and in disease. PMID:24492712

  8. Telephone multiline signaling using common signal pair

    NASA Technical Reports Server (NTRS)

    Goodloe, R. R.; Toole, P. C.; Belt, J. L.; Leininger, D. B. (Inventor)

    1979-01-01

    An operator can rapidly and automatically produce coded electrical signals by manipulating mechanical thumb wheel switches so as to instruct a service center to connect any number of telephone lines to the console thus enabling the operator to listen and/or talk over several lines simultaneously. The system includes an on-site console having several mechanically operated thumb wheel switches to which the desired lines to be connected can be dialed in. Electrical coded signals are fed to a number of banks of line AND gates representing units, tens and hundreds, a group of channel gates, and a command gate. These signals are gated out in a controlled manner to an encoder which generates tones that are transmitted over a single line to a communication service center.

  9. Quantitation of signal transduction.

    PubMed

    Krauss, S; Brand, M D

    2000-12-01

    Conventional qualitative approaches to signal transduction provide powerful ways to explore the architecture and function of signaling pathways. However, at the level of the complete system, they do not fully depict the interactions between signaling and metabolic pathways and fail to give a manageable overview of the complexity that is often a feature of cellular signal transduction. Here, we introduce a quantitative experimental approach to signal transduction that helps to overcome these difficulties. We present a quantitative analysis of signal transduction during early mitogen stimulation of lymphocytes, with steady-state respiration rate as a convenient marker of metabolic stimulation. First, by inhibiting various key signaling pathways, we measure their relative importance in regulating respiration. About 80% of the input signal is conveyed via identifiable routes: 50% through pathways sensitive to inhibitors of protein kinase C and MAP kinase and 30% through pathways sensitive to an inhibitor of calcineurin. Second, we quantify how each of these pathways differentially stimulates functional units of reactions that produce and consume a key intermediate in respiration: the mitochondrial membrane potential. Both the PKC and calcineurin routes stimulate consumption more strongly than production, whereas the unidentified signaling routes stimulate production more than consumption, leading to no change in membrane potential despite increased respiration rate. The approach allows a quantitative description of the relative importance of signal transduction pathways and the routes by which they activate a specific cellular process. It should be widely applicable.

  10. UWB Monitoring System for AAL Applications

    PubMed Central

    Kolakowski, Jerzy

    2017-01-01

    Independent living of elderly persons in their homes requires support that can be provided with modern assistive technologies. Monitoring of elderly persons behaviour delivers valuable information that can be used for diagnosis and detection of health problems as well as triggering alerts in emergency situations. The paper includes a description of the ultra wideband system developed within Networked InfrasTructure for Innovative home Care Solutions (NITICS) Active and Assisted Living (AAL) project. The system can be used as a component of AAL platforms. It delivers data on users localization and has a fall detector functionality. The system also provides access to raw measurement results from Microelectromechanical Systems (MEMS) sensors embedded in the device worn by the monitored person. These data can be used in solutions intended for elderly person’s behaviour investigation. The system was investigated under laboratory conditions as well as in home environment. The detailed system description and results of performed tests are included in the article. PMID:28895917

  11. Assessment of Ultra-Wideband (UWB) Technology

    DTIC Science & Technology

    1990-07-13

    planar antenna arrays . The suggested level of effort of each study is one person-year. (3) The Panel recommends that the...ultra-wideband linear and planar antenna arrays should be accomplished. (4) TRANSMITTER/SOURCE Although the continued development DESIGN of potential...because it is difficult to have low antenna sidelobes with an impulse radar. This is especially true when the radar employs a phased array antenna .

  12. Time-Reversal for UWB Communications Systems

    DTIC Science & Technology

    2005-08-15

    2000. 55. S. Kim, G. F. Edelmann , W. A. Kuperman, W. S. Hodgkiss, and H. G. Song, “Spatial resolution of time-reversal arrays in shallow water,” J...694–696, 2002. 58. G. F. Edelmann , T. Akal, W. S. Hodgkiss, S. Kim, W. A. Kuperman and H. C. Song, “An Initial Demonstration Of Underwater Acoustic

  13. Wnt signaling in cancer

    PubMed Central

    Zhan, T; Rindtorff, N; Boutros, M

    2017-01-01

    Wnt signaling is one of the key cascades regulating development and stemness, and has also been tightly associated with cancer. The role of Wnt signaling in carcinogenesis has most prominently been described for colorectal cancer, but aberrant Wnt signaling is observed in many more cancer entities. Here, we review current insights into novel components of Wnt pathways and describe their impact on cancer development. Furthermore, we highlight expanding functions of Wnt signaling for both solid and liquid tumors. We also describe current findings how Wnt signaling affects maintenance of cancer stem cells, metastasis and immune control. Finally, we provide an overview of current strategies to antagonize Wnt signaling in cancer and challenges that are associated with such approaches. PMID:27617575

  14. [Growth hormone signaling pathways].

    PubMed

    Zych, Sławomir; Szatkowska, Iwona; Czerniawska-Piatkowska, Ewa

    2006-01-01

    The substantial improvement in the studies on a very complicated mechanism-- growth hormone signaling in a cell, has been noted in last decade. GH-induced signaling is characterized by activation of several pathways, including extracellular signal-regulated kinase (ERK), the signal transducer and activator of transcription and phosphatidylinositol-3 kinase (PI3) pathways. This review shows a current model of the growth hormone receptor dimerization, rotation of subunits and JAK2 kinase activation as the initial steps in the cascade of events. In the next stages of the signaling process, the GH-(GHR)2-(JAK2)2 complex may activate signaling molecules such as Stat, IRS-1 and IRS-2, and particularly all cascade proteins that activate MAP kinase. These pathways regulate basal cellular functions including target gene transcription, enzymatic activity and metabolite transport. Therefore growth hormone is considered as a major regulator of postnatal growth and metabolism, probably for mammary gland growth and development too.

  15. Optical signal processing

    NASA Technical Reports Server (NTRS)

    Casasent, D.

    1978-01-01

    The article discusses several optical configurations used for signal processing. Electronic-to-optical transducers are outlined, noting fixed window transducers and moving window acousto-optic transducers. Folded spectrum techniques are considered, with reference to wideband RF signal analysis, fetal electroencephalogram analysis, engine vibration analysis, signal buried in noise, and spatial filtering. Various methods for radar signal processing are described, such as phased-array antennas, the optical processing of phased-array data, pulsed Doppler and FM radar systems, a multichannel one-dimensional optical correlator, correlations with long coded waveforms, and Doppler signal processing. Means for noncoherent optical signal processing are noted, including an optical correlator for speech recognition and a noncoherent optical correlator.

  16. Optical Signal Processing

    DTIC Science & Technology

    1990-02-28

    compatible with the laser cation in the on-line inspection of products such as source. Thus, if the laser wavelength is z850 nm, hypodermic needles ...content for cw signals, short pulse signals, and evolving pulse signals - - the most difficult ones to analyze. We performed an extensive analysis on a...agreer.nt with the theory , and support our claims concerning the high performance level of our acousto-optir. architecture. We recognized the opportunity to

  17. Signaling Mechanisms for Chemotaxis

    PubMed Central

    Wang, Yu; Chen, Chun-Lin; Iijima, Miho

    2011-01-01

    Cells recognize external chemical gradients and translate these environmental cues into amplified intracellular signaling that results in elongated cell shape, actin polymerization toward the leading edge, and movement along the gradient. Mechanisms underlying chemotaxis are conserved evolutionarily from Dictyostelium amoeba to mammalian neutrophils. Recent studies have uncovered several parallel intracellular signaling pathways that crosstalk in chemotaxing cells. Here, we review these signaling mechanisms in Dictyostelium discoideum. PMID:21585354

  18. Danger signals in stroke.

    PubMed

    Gelderblom, Mathias; Sobey, Christopher G; Kleinschnitz, Christoph; Magnus, Tim

    2015-11-01

    Danger molecules are the first signals released from dying tissue after stroke. These danger signals bind to receptors on immune cells that will result in their activation and the release of inflammatory and neurotoxic mediators, resulting in amplification of the immune response and subsequent enlargement of the damaged brain volume. The release of danger signals is a central event that leads to a multitude of signals and cascades in the affected and neighbouring tissue, therefore providing a potential target for therapy. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Slit-Robo signaling.

    PubMed

    Blockus, Heike; Chédotal, Alain

    2016-09-01

    Slits are secreted proteins that bind to Roundabout (Robo) receptors. Slit-Robo signaling is best known for mediating axon repulsion in the developing nervous system. However, in recent years the functional repertoire of Slits and Robo has expanded tremendously and Slit-Robo signaling has been linked to roles in neurogenesis, angiogenesis and cancer progression among other processes. Likewise, our mechanistic understanding of Slit-Robo signaling has progressed enormously. Here, we summarize new insights into Slit-Robo evolutionary and system-dependent diversity, receptor-ligand interactions, signaling crosstalk and receptor activation.

  20. Signaling by Gasotransmitters

    PubMed Central

    Mustafa, Asif K.; Gadalla, Moataz M.; Snyder, Solomon H.

    2009-01-01

    Nitric oxide is well established as a major signaling molecule. Evidence is accumulating that carbon monoxide and hydrogen sulfide also are physiologic mediators in the cardiovascular, immune, and nervous systems. This Review focuses on mechanisms whereby they signal by binding to metal centers in metalloproteins, such as in guanylyl cyclase, or modifying sulfhydryl groups in protein targets. PMID:19401594

  1. MBA Quality Signals.

    ERIC Educational Resources Information Center

    Chapman, Randall S.

    1998-01-01

    A study identified quality signals for master's programs in business administration (MBAs). Traditional scholarly oriented academic signals are apparently not valued as such by external customer groups. MBA academic quality appears to be a multidimensional construct, with subdimensions of real-worldness; placement; student satisfaction; and…

  2. Geophysical Signal Recognition,

    DTIC Science & Technology

    1981-01-01

    quite helpful in the magnetosphere. Detecting a particular in earthquake prediction . However pattern recog- micropulsation event can provide a diagnosis...bio- In su..a.iry, application of pattern recognition to medical signals, progress in geophysical signal earthquake prediction is in its infancy

  3. MBA Quality Signals.

    ERIC Educational Resources Information Center

    Chapman, Randall S.

    1998-01-01

    A study identified quality signals for master's programs in business administration (MBAs). Traditional scholarly oriented academic signals are apparently not valued as such by external customer groups. MBA academic quality appears to be a multidimensional construct, with subdimensions of real-worldness; placement; student satisfaction; and…

  4. Adaptive signal processor

    SciTech Connect

    Walz, H.V.

    1980-07-01

    An experimental, general purpose adaptive signal processor system has been developed, utilizing a quantized (clipped) version of the Widrow-Hoff least-mean-square adaptive algorithm developed by Moschner. The system accommodates 64 adaptive weight channels with 8-bit resolution for each weight. Internal weight update arithmetic is performed with 16-bit resolution, and the system error signal is measured with 12-bit resolution. An adapt cycle of adjusting all 64 weight channels is accomplished in 8 ..mu..sec. Hardware of the signal processor utilizes primarily Schottky-TTL type integrated circuits. A prototype system with 24 weight channels has been constructed and tested. This report presents details of the system design and describes basic experiments performed with the prototype signal processor. Finally some system configurations and applications for this adaptive signal processor are discussed.

  5. Jasmonate signalling: a copycat of auxin signalling?

    PubMed

    Pérez, A Cuéllar; Goossens, A

    2013-12-01

    Plant hormones regulate almost all aspects of plant growth and development. The past decade has provided breakthrough discoveries in phytohormone sensing and signal transduction, and highlighted the striking mechanistic similarities between the auxin and jasmonate (JA) signalling pathways. Perception of auxin and JA involves the formation of co-receptor complexes in which hormone-specific E3-ubiquitin ligases of the SKP1-Cullin-F-box protein (SCF) type interact with specific repressor proteins. Across the plant kingdom, the Aux/IAA and the JASMONATE-ZIM DOMAIN (JAZ) proteins correspond to the auxin- and JA-specific repressors, respectively. In the absence of the hormones, these repressors form a complex with transcription factors (TFs) specific for both pathways. They also recruit several proteins, among which the general co-repressor TOPLESS, and thereby prevent the TFs from activating gene expression. The hormone-mediated interaction between the SCF and the repressors targets the latter for 26S proteasome-mediated degradation, which, in turn, releases the TFs to allow modulating hormone-dependent gene expression. In this review, we describe the similarities and differences in the auxin and JA signalling cascades with respect to the protein families and the protein domains involved in the formation of the pathway-specific complexes.

  6. Deblurring Signal Network Dynamics.

    PubMed

    Kamps, Dominic; Dehmelt, Leif

    2017-09-15

    To orchestrate the function and development of multicellular organisms, cells integrate intra- and extracellular information. This information is processed via signal networks in space and time, steering dynamic changes in cellular structure and function. Defects in those signal networks can lead to developmental disorders or cancer. However, experimental analysis of signal networks is challenging as their state changes dynamically and differs between individual cells. Thus, causal relationships between network components are blurred if lysates from large cell populations are analyzed. To directly study causal relationships, perturbations that target specific components have to be combined with measurements of cellular responses within individual cells. However, using standard single-cell techniques, the number of signal activities that can be monitored simultaneously is limited. Furthermore, diffusion of signal network components limits the spatial precision of perturbations, which blurs the analysis of spatiotemporal processing in signal networks. Hybrid strategies based on optogenetics, surface patterning, chemical tools, and protein design can overcome those limitations and thereby sharpen our view into the dynamic spatiotemporal state of signal networks and enable unique insights into the mechanisms that control cellular function in space and time.

  7. Plant Cyclic Nucleotide Signalling

    PubMed Central

    Martinez-Atienza, Juliana; Van Ingelgem, Carl; Roef, Luc

    2007-01-01

    The presence of the cyclic nucleotides 3′,5′-cyclic adenyl monophosphate (cAMP) and 3′,5′-cyclic guanyl monophosphate (cGMP) in plants is now generally accepted. In addition, cAMP and cGMP have been implicated in the regulation of important plant processes such as stomatal functioning, monovalent and divalent cation fluxes, chloroplast development, gibberellic acid signalling, pathogen response and gene transcription. However, very little is known regarding the components of cyclic nucleotide signalling in plants. In this addendum, the evidence for specific mechanisms of plant cyclic nucleotide signalling is evaluated and discussed. PMID:19704553

  8. Electrical signaling and photosynthesis

    PubMed Central

    Mancuso, Stefano

    2011-01-01

    Mechanical irritation of trigger hairs and subsequent generation of action potentials have significant impact on photosynthesis and respiration in carnivorous Venus flytrap (Dionaea muscipula). Action potential-mediated inhibition of photosynthesis and stimulation of respiration is confined only to the trap and was not recorded in adjacent photosynthetic lamina. We showed that the main primary target of electrical signals on assimilation is in the dark enzymatic reaction of photosynthesis. Without doubt, the electrical signaling is costly, and the possible co-existence of such type of signals and photosynthesis in plant cell is discussed. PMID:21558815

  9. Aestivation: signaling and hypometabolism.

    PubMed

    Storey, Kenneth B; Storey, Janet M

    2012-05-01

    Aestivation is a survival strategy used by many vertebrates and invertebrates to endure arid environmental conditions. Key features of aestivation include strong metabolic rate suppression, strategies to retain body water, conservation of energy and body fuel reserves, altered nitrogen metabolism, and mechanisms to preserve and stabilize organs, cells and macromolecules over many weeks or months of dormancy. Cell signaling is crucial to achieving both a hypometabolic state and reorganizing multiple metabolic pathways to optimize long-term viability during aestivation. This commentary examines the current knowledge about cell signaling pathways that participate in regulating aestivation, including signaling cascades mediated by the AMP-activated kinase, Akt, ERK, and FoxO1.

  10. GNSS Ocean Reflected Signals

    NASA Astrophysics Data System (ADS)

    Hoeg, P.

    2012-12-01

    Ocean reflected signals from the GNSS satellites (received at low-Earth orbiting satellites, airplanes and fixed mountain locations) describe the ocean surface mean height, waves, roughness, spectral reflectivity and emissivity. The estimated accuracy of the average surface height is of the order of 10 cm for smooth conditions. Thus global observations could be an important new contribution to long-term variations of the ocean mean height as well as the monitoring of ocean mesoscale eddies, which result in sea-height changes much larger than the accuracy of the GNSS technique for reflected signals. The ocean reflected signals can be divided into two set of measurements, 1) high elevation measurements (equal to low incidence angles) and 2) low elevation grazing angle measurements. For the first type the ocean reflection cross-section has a limited extent. The reflected signal is coherent with smaller errors due to ocean waves, sampling rate and the internal processing method of the receiver. For low elevations, the signal reveals the incoherent scatter process at the reflection zone. To quantify the potential of the GNSS signals for determining spectral reflectivity at low elevations, we present ocean reflection GPS measurements from the Haleakala Summit on Maui, Hawaii, revealing the spectral characteristics of both the direct satellite signal and the ocean reflected signal for low elevation angles. The characteristics of the reflected signal depend on the scattering properties of the sea surface and the footprint of the reflection zone. While the footprint size and shape in turn depends on the signal incidence angle, the ocean mean tilt, and the relative velocities of transmitter and receiver to the reflection point. Thus the scattering properties of the sea surface are related to the sea surface roughness. We present the spectral properties of the signals as received by a high precision GPS instrument, simultaneously in both phase-locked mode and open-loop raw

  11. Peptide signaling in Hydra.

    PubMed

    Fujisawa, Toshitaka; Hayakawa, Eisuke

    2012-01-01

    Peptides play a number of crucial roles as signaling molecules in metazoans. In order to elaborate a more complete picture of the roles played by peptides in a single organism, we launched the "Hydra Peptide Project". For this project, we used Hydra magnipapillata, a species belonging to Cnidaria, one of the most basal metazoan phyla, and using a peptidomic approach, we systematically identified a number of peptide signaling molecules, their encoding genes and their functions. In this article, we report the peptides isolated from Hydra and other cnidarians, as well as their synthesis, processing and release from the cells to the target. Possible peptide signaling pathways are overviewed and finally we discuss the evolution of the peptide signaling system.

  12. Signal processing in SETI

    NASA Technical Reports Server (NTRS)

    Cullers, D. K.; Linscott, I. R.; Oliver, B. M.

    1985-01-01

    It is believed that the Galaxy might contain ten billion potential life sites. In view of the physical inaccessibility of extraterrestrial life on account of the vast distances involved, a logical first step in a search for extraterrestrial intelligence (SETI) appears to be an attempt to detect signals already being radiated. The characteristics of the signals to be expected are discussed together with the search strategy of a NASA program. It is pointed out that all presently planned searches will use existing radio-astronomy antennas. If no extraterrestrial intelligence signals are discovered, society will have to decide whether SETI justifies a dedicated facility of much greater collecting area. Attention is given to a multichannel spectrum analyzer, CW signal detection, pulse detection, the pattern detector, and details of SETI system operation.

  13. Nucleotide signalling during inflammation

    PubMed Central

    Idzko, Marco; Ferrari, Davide; Eltzschig, Holger K.

    2014-01-01

    Inflammatory conditions are associated with the extracellular release of nucleotides, particularly ATP. In the extracellular compartment, ATP predominantly functions as a signalling molecule through the activation of purinergic P2 receptors. Metabotropic P2Y receptors are G-protein-coupled, whereas ionotropic P2X receptors are ATP-gated ion channels. Here we discuss how signalling events through P2 receptors alter the outcomes of inflammatory or infectious diseases. Recent studies implicate a role for P2X/P2Ysignalling in mounting appropriate inflammatory responses critical for host defence against invading pathogens or tumours. Conversely, P2X/P2Y signalling can promote chronic inflammation during ischaemia and reperfusion injury, inflammatory bowel disease or acute and chronic diseases of the lungs. Although nucleotide signalling has been used clinically in patients before, research indicates an expanding field of opportunities for specifically targeting individual P2 receptors for the treatment of inflammatory or infectious diseases. PMID:24828189

  14. Audio signal processor

    NASA Technical Reports Server (NTRS)

    Hymer, R. L.

    1970-01-01

    System provides automatic volume control for an audio amplifier or a voice communication system without introducing noise surges during pauses in the input, and without losing the initial signal when the input resumes.

  15. Signals from the Cosmos.

    ERIC Educational Resources Information Center

    Lichtman, Jeffrey M.

    1991-01-01

    Introduces the basics of radio astronomy and describes how to assemble several simple systems for receiving radio signals from the cosmos. Includes schematics, parts lists, working drawings, and contact information for radio astronomy suppliers. (11 references) (Author/JJK)

  16. Transmembrane Signalling: Membrane messengers

    NASA Astrophysics Data System (ADS)

    Cockroft, Scott L.

    2017-05-01

    Life has evolved elaborate means of communicating essential chemical information across cell membranes. Inspired by biology, two new artificial mechanisms have now been developed that use synthetic messenger molecules to relay chemical signals into or across lipid membranes.

  17. Quantifying Ubiquitin Signaling

    PubMed Central

    Ordureau, Alban; Münch, Christian; Harper, J. Wade

    2015-01-01

    Ubiquitin (UB)-driven signaling systems permeate biology, and are often integrated with other types of post-translational modifications (PTMs), most notably phosphorylation. Flux through such pathways is typically dictated by the fractional stoichiometry of distinct regulatory modifications and protein assemblies as well as the spatial organization of pathway components. Yet, we rarely understand the dynamics and stoichiometry of rate-limiting intermediates along a reaction trajectory. Here, we review how quantitative proteomic tools and enrichment strategies are being used to quantify UB-dependent signaling systems, and to integrate UB signaling with regulatory phosphorylation events. A key regulatory feature of ubiquitylation is that the identity of UB chain linkage types can control downstream processes. We also describe how proteomic and enzymological tools can be used to identify and quantify UB chain synthesis and linkage preferences. The emergence of sophisticated quantitative proteomic approaches will set a new standard for elucidating biochemical mechanisms of UB-driven signaling systems. PMID:26000850

  18. Signals from the Cosmos.

    ERIC Educational Resources Information Center

    Lichtman, Jeffrey M.

    1991-01-01

    Introduces the basics of radio astronomy and describes how to assemble several simple systems for receiving radio signals from the cosmos. Includes schematics, parts lists, working drawings, and contact information for radio astronomy suppliers. (11 references) (Author/JJK)

  19. Signal processing in SETI

    NASA Technical Reports Server (NTRS)

    Cullers, D. K.; Linscott, I. R.; Oliver, B. M.

    1985-01-01

    It is believed that the Galaxy might contain ten billion potential life sites. In view of the physical inaccessibility of extraterrestrial life on account of the vast distances involved, a logical first step in a search for extraterrestrial intelligence (SETI) appears to be an attempt to detect signals already being radiated. The characteristics of the signals to be expected are discussed together with the search strategy of a NASA program. It is pointed out that all presently planned searches will use existing radio-astronomy antennas. If no extraterrestrial intelligence signals are discovered, society will have to decide whether SETI justifies a dedicated facility of much greater collecting area. Attention is given to a multichannel spectrum analyzer, CW signal detection, pulse detection, the pattern detector, and details of SETI system operation.

  20. Optical Signal Processing.

    DTIC Science & Technology

    1986-10-31

    8217 \\..\\ We let k be the ratio of the time base of the reference\\ \\ . signal to that of the received signal. PAU~ ~; II .~** We could analyze this case for an...decreases. The central to the approximation usually stated in optics texts. lobe of the pattern just covers the region II :s I when k We claimed...Reference Waveforms for Heterodyne Spectrum Analyzers K We previously developed the use of a distributed local oscillator, generated by a reference wavefront

  1. Dissecting DR3 signaling.

    PubMed

    Pobezinskaya, Yelena L; Liu, Zhenggang; Choksi, Swati

    2014-01-01

    Receptor signaling can be evaluated in multiple ways, including analysis of phosphorylation of downstream molecules and analysis of proteins that are recruited to the receptor upon ligand binding. Majority of studies on the mechanism of DR3 signaling were performed using overexpression systems that can often lead to artifacts. In this chapter we describe how to analyze DR3 downstream events with most attention being paid to endogenous immunoprecipitation.

  2. Wnt signaling and osteoporosis

    PubMed Central

    Manolagas, Stavros C.

    2014-01-01

    Major advances in understanding basic bone biology and the cellular and molecular mechanisms responsible for the development of osteoporosis, over the last 20 years, have dramatically altered the management of this disease. The purpose of this mini-review is to highlight the seminal role of Wnt signaling in bone homeostasis and disease and the emergence of novel osteoporosis therapies by targeting Wnt signaling with drugs. PMID:24815296

  3. Signal-light nomogram

    NASA Technical Reports Server (NTRS)

    Gordon, J. I.; Edgerton, C. F.; Duntley, S. Q.

    1975-01-01

    A nomogram is presented for predicting the sighting range for white, steady-burning signal lights. The theoretical and experimental bases are explained and instructions are provided for its use for a variety of practical problems concerning the visibility of signal lights. The nomogram is appropriate for slant path as well as horizontal sightings, and the gain of range achieved by utilizing binoculars can be predicted by use of it.

  4. Digital signal processing

    NASA Astrophysics Data System (ADS)

    Oppenheim, A. V.; Baggeroer, A. B.; Lim, J. S.; Musicus, B. R.; Mook, D. R.; Duckworth, G. L.; Bordley, T. E.; Curtis, S. R.; Deadrick, D. S.; Dove, W. P.

    1984-01-01

    Signal and image processing research projects are described. Topics include: (1) modeling underwater acoustic propagation; (2) image restoration; (3) signal reconstruction; (4) speech enhancement; (5) pitch detection; (6) spectral analysis; (7) speech synthesis; (8) speech enhancement; (9) autoregressive spectral estimation; (10) knowledge based array processing; (11) speech analysis; (12) estimating the degree of coronary stenosis with image processing; (13) automatic target detection; and (14) video conferencing.

  5. Redox signaling in plants.

    PubMed

    Foyer, Christine H; Noctor, Graham

    2013-06-01

    Our aim is to deliver an authoritative and challenging perspective of current concepts in plant redox signaling, focusing particularly on the complex interface between the redox and hormone-signaling pathways that allow precise control of plant growth and defense in response to metabolic triggers and environmental constraints and cues. Plants produce significant amounts of singlet oxygen and other reactive oxygen species (ROS) as a result of photosynthetic electron transport and metabolism. Such pathways contribute to the compartment-specific redox-regulated signaling systems in plant cells that convey information to the nucleus to regulate gene expression. Like the chloroplasts and mitochondria, the apoplast-cell wall compartment makes a significant contribution to the redox signaling network, but unlike these organelles, the apoplast has a low antioxidant-buffering capacity. The respective roles of ROS, low-molecular antioxidants, redox-active proteins, and antioxidant enzymes are considered in relation to the functions of plant hormones such as salicylic acid, jasmonic acid, and auxin, in the composite control of plant growth and defense. Regulation of redox gradients between key compartments in plant cells such as those across the plasma membrane facilitates flexible and multiple faceted opportunities for redox signaling that spans the intracellular and extracellular environments. In conclusion, plants are recognized as masters of the art of redox regulation that use oxidants and antioxidants as flexible integrators of signals from metabolism and the environment.

  6. Cytokinin signaling networks.

    PubMed

    Hwang, Ildoo; Sheen, Jen; Müller, Bruno

    2012-01-01

    Despite long-standing observations on diverse cytokinin actions, the discovery path to cytokinin signaling mechanisms was tortuous. Unyielding to conventional genetic screens, experimental innovations were paramount in unraveling the core cytokinin signaling circuitry, which employs a large repertoire of genes with overlapping and specific functions. The canonical two-component transcription circuitry involves His kinases that perceive cytokinin and initiate signaling, as well as His-to-Asp phosphorelay proteins that transfer phosphoryl groups to response regulators, transcriptional activators, or repressors. Recent advances have revealed the complex physiological functions of cytokinins, including interactions with auxin and other signal transduction pathways. This review begins by outlining the historical path to cytokinin discovery and then elucidates the diverse cytokinin functions and key signaling components. Highlights focus on the integration of cytokinin signaling components into regulatory networks in specific contexts, ranging from molecular, cellular, and developmental regulations in the embryo, root apical meristem, shoot apical meristem, stem and root vasculature, and nodule organogenesis to organismal responses underlying immunity, stress tolerance, and senescence.

  7. Sucrose signaling in plants

    PubMed Central

    Tognetti, Jorge A.; Pontis, Horacio G.; Martínez-Noël, Giselle M.A.

    2013-01-01

    The role of sucrose as a signaling molecule in plants was originally proposed several decades ago. However, recognition of sucrose as a true signal has been largely debated and only recently this role has been fully accepted. The best-studied cases of sucrose signaling involve metabolic processes, such as the induction of fructan or anthocyanin synthesis, but a large volume of scattered information suggests that sucrose signals may control a vast array of developmental processes along the whole life cycle of the plant. Also, wide gaps exist in our current understanding of the intracellular steps that mediate sucrose action. Sucrose concentration in plant tissues tends to be directly related to light intensity, and inversely related to temperature, and accordingly, exogenous sucrose supply often mimics the effect of high light and cold. However, many exceptions to this rule seem to occur due to interactions with other signaling pathways. In conclusion, the sucrose role as a signal molecule in plants is starting to be unveiled and much research is still needed to have a complete map of its significance in plant function. PMID:23333971

  8. Calcium signaling and cytotoxicity.

    PubMed Central

    Kass, G E; Orrenius, S

    1999-01-01

    The divalent calcium cation Ca(2+) is used as a major signaling molecule during cell signal transduction to regulate energy output, cellular metabolism, and phenotype. The basis to the signaling role of Ca(2+) is an intricate network of cellular channels and transporters that allow a low resting concentration of Ca(2+) in the cytosol of the cell ([Ca(2+)]i) but that are also coupled to major dynamic and rapidly exchanging stores. This enables extracellular signals from hormones and growth factors to be transduced as [Ca(2+)]i spikes that are amplitude and frequency encoded. There is considerable evidence that a number of toxic environmental chemicals target these Ca(2+) signaling processes, alter them, and induce cell death by apoptosis. Two major pathways for apoptosis will be considered. The first one involves Ca(2+)-mediated expression of ligands that bind to and activate death receptors such as CD95 (Fas, APO-1). In the second pathway, Ca(2+) has a direct toxic effect and its primary targets include the mitochondria and the endoplasmic reticulum (ER). Mitochondria may respond to an apoptotic Ca(2+) signal by the selective release of cytochrome c or through enhanced production of reactive oxygen species and opening of an inner mitochondrial membrane pore. Toxic agents such as the environmental pollutant tributyltin or the natural plant product thapsigargin, which deplete the ER Ca(2+) stores, will induce as a direct result of this effect the opening of plasma membrane Ca(2+) channels and an ER stress response. In contrast, under some conditions, Ca(2+) signals may be cytoprotective and antagonize the apoptotic machinery. Images Figure 1 Figure 2 Figure 3 PMID:10229704

  9. Purinergic signalling and diabetes.

    PubMed

    Burnstock, Geoffrey; Novak, Ivana

    2013-09-01

    The pancreas is an organ with a central role in nutrient breakdown, nutrient sensing and release of hormones regulating whole body nutrient homeostasis. In diabetes mellitus, the balance is broken-cells can be starving in the midst of plenty. There are indications that the incidence of diabetes type 1 and 2, and possibly pancreatogenic diabetes, is rising globally. Events leading to insulin secretion and action are complex, but there is emerging evidence that intracellular nucleotides and nucleotides are not only important as intracellular energy molecules but also as extracellular signalling molecules in purinergic signalling cascades. This signalling takes place at the level of the pancreas, where the close apposition of various cells-endocrine, exocrine, stromal and immune cells-contributes to the integrated function. Following an introduction to diabetes, the pancreas and purinergic signalling, we will focus on the role of purinergic signalling and its changes associated with diabetes in the pancreas and selected tissues/organ systems affected by hyperglycaemia and other stress molecules of diabetes. Since this is the first review of this kind, a comprehensive historical angle is taken, and common and divergent roles of receptors for nucleotides and nucleosides in different organ systems will be given. This integrated picture will aid our understanding of the challenges of the potential and currently used drugs targeted to specific organ/cells or disorders associated with diabetes.

  10. Spotforming with an Array of Ultra-Wideband Radio Transmitters

    SciTech Connect

    Dowla, F; Spiridon, A

    2003-09-29

    Ultra-wideband (UWB) array signal processing has the distinct advantage in that it is possible to illuminate or focus on ''spots'' at distant points in space, as opposed to just illuminating or steering at certain directions for narrowband array processing. The term ''spotforming'' is used to emphasize the property that point-focusing techniques with UWB waveforms can be viewed as a generalization of the well-known narrowband beamforming techniques. Because methods in spotforming can lead to powerful applications for UWB systems, in this paper we derive, simulate and experimentally verify UWB spot size as a function of frequency, bandwidth and array aperture.

  11. Spotforming with an array of ultra-wideband radio transmitters

    SciTech Connect

    Dowla, F; Spiridon, A

    2004-02-05

    Ultra-wideband (UWB) array signal processing has the distinct advantage in that it is possible to illuminate or focus on ''spots'' at distant points in space, as opposed to just illuminating or steering at certain directions for narrowband array processing. The term ''spotforming'' is used to emphasize the property that point-focusing techniques with UWB waveforms can be viewed as a generalization of the well-known narrowband beamforming techniques. Because methods in spotforming can lead to powerful applications for UWB systems, in this paper we derive, simulate and experimentally verify UWB spot size as a function of frequency, bandwidth and array aperture.

  12. Separation of Climate Signals

    SciTech Connect

    Kamath, C; Fodor, I

    2002-11-13

    Understanding changes in global climate is a challenging scientific problem. Simulated and observed data include signals from many sources, and untangling their respective effects is difficult. In order to make meaningful comparisons between different models, and to understand human effects on global climate, we need to isolate the effects of different sources. Recent eruptions of the El Chichon and Mt. Pinatubo volcanoes coincided with large El Nino and Southern Oscillation (ENSO) events, which complicates the separation of their contributions on global temperatures. Current approaches for separating volcano and ENSO signals in global mean data involve parametric models and iterative techniques [3]. We investigate alternative methods based on principal component analysis (PCA) [2] and independent component analysis (ICA) [1]. Our goal is to determine if such techniques can automatically identify the signals corresponding to the different sources, without relying on parametric models.

  13. Integrin signaling in atherosclerosis.

    PubMed

    Finney, Alexandra C; Stokes, Karen Y; Pattillo, Christopher B; Orr, A Wayne

    2017-06-01

    Atherosclerosis, a chronic lipid-driven inflammatory disease affecting large arteries, represents the primary cause of cardiovascular disease in the world. The local remodeling of the vessel intima during atherosclerosis involves the modulation of vascular cell phenotype, alteration of cell migration and proliferation, and propagation of local extracellular matrix remodeling. All of these responses represent targets of the integrin family of cell adhesion receptors. As such, alterations in integrin signaling affect multiple aspects of atherosclerosis, from the earliest induction of inflammation to the development of advanced fibrotic plaques. Integrin signaling has been shown to regulate endothelial phenotype, facilitate leukocyte homing, affect leukocyte function, and drive smooth muscle fibroproliferative remodeling. In addition, integrin signaling in platelets contributes to the thrombotic complications that typically drive the clinical manifestation of cardiovascular disease. In this review, we examine the current literature on integrin regulation of atherosclerotic plaque development and the suitability of integrins as potential therapeutic targets to limit cardiovascular disease and its complications.

  14. Telemetry Ranging: Signal Processing

    NASA Astrophysics Data System (ADS)

    Hamkins, J.; Kinman, P.; Xie, H.; Vilnrotter, V.; Dolinar, S.

    2016-02-01

    This article describes the details of the signal processing used in a telemetry ranging system in which timing information is extracted from the downlink telemetry signal in order to compute spacecraft range. A previous article describes telemetry ranging concepts and architecture, which are a slight variation of a scheme published earlier. As in that earlier work, the telemetry ranging concept eliminates the need for a dedicated downlink ranging signal to communicate the necessary timing information. The present article describes the operation and performance of the major receiver functions on the spacecraft and the ground --- many of which are standard tracking loops already in use in JPL's flight and ground radios --- and how they can be used to provide the relevant information for making a range measurement. It also describes the implementation of these functions in software, and performance of an end-to-end software simulation of the telemetry ranging system.

  15. Updating dopamine reward signals

    PubMed Central

    Schultz, Wolfram

    2013-01-01

    Recent work has advanced our knowledge of phasic dopamine reward prediction error signals. The error signal is bidirectional, reflects well the higher order prediction error described by temporal difference learning models, is compatible with model-free and model-based reinforcement learning, reports the subjective rather than physical reward value during temporal discounting and reflects subjective stimulus perception rather than physical stimulus aspects. Dopamine activations are primarily driven by reward, and to some extent risk, whereas punishment and salience have only limited activating effects when appropriate controls are respected. The signal is homogeneous in terms of time course but heterogeneous in many other aspects. It is essential for synaptic plasticity and a range of behavioural learning situations. PMID:23267662

  16. Plant TOR signaling components

    PubMed Central

    John, Florian; Roffler, Stefan; Wicker, Thomas; Ringli, Christoph

    2011-01-01

    Cell growth is a process that needs to be tightly regulated. Cells must be able to sense environmental factors like nutrient abundance, the energy level or stress signals and coordinate growth accordingly. The Target Of Rapamycin (TOR) pathway is a major controller of growth-related processes in all eukaryotes. If environmental conditions are favorable, the TOR pathway promotes cell and organ growth and restrains catabolic processes like autophagy. Rapamycin is a specific inhibitor of the TOR kinase and acts as a potent inhibitor of TOR signaling. As a consequence, interfering with TOR signaling has a strong impact on plant development. This review summarizes the progress in the understanding of the biological significance and the functional analysis of the TOR pathway in plants. PMID:22057328

  17. Endocytosis, Signaling, and Beyond

    PubMed Central

    Di Fiore, Pier Paolo; von Zastrow, Mark

    2014-01-01

    The endocytic network comprises a vast and intricate system of membrane-delimited cell entry and cargo sorting routes running between biochemically and functionally distinct intracellular compartments. The endocytic network caters to the organization and redistribution of diverse subcellular components, and mediates appropriate shuttling and processing of materials acquired from neighboring cells or the extracellular milieu. Such trafficking logistics, despite their importance, represent only one facet of endocytic function. The endocytic network also plays a key role in organizing, mediating, and regulating cellular signal transduction events. Conversely, cellular signaling processes tightly control the endocytic pathway at different steps. The present article provides a perspective on the intimate relationships that exist between particular endocytic and cellular signaling processes in mammalian cells, within the context of understanding the impact of this nexus on integrated physiology. PMID:25085911

  18. PKD signaling and pancreatitis

    PubMed Central

    Yuan, Jingzhen; Pandol, Stephen J.

    2016-01-01

    Background Acute pancreatitis is a serious medical disorder with no current therapies directed to the molecular pathogenesis of the disorder. Inflammation, inappropriate intracellular activation of digestive enzymes, and parenchymal acinar cell death by necrosis are the critical pathophysiologic processes of acute pancreatitis. Thus, it is necessary to elucidate the key molecular signals that mediate these pathobiologic processes and develop new therapeutic strategies to attenuate the appropriate signaling pathways in order to improve outcomes for this disease. A novel serine/threonine protein kinase D (PKD) family has emerged as key participants in signal transduction, and this family is increasingly being implicated in the regulation of multiple cellular functions and diseases. Methods This review summarizes recent findings of our group and others regarding the signaling pathway and the biological roles of the PKD family in pancreatic acinar cells. In particular, we highlight our studies of the functions of PKD in several key pathobiologic processes associated with acute pancreatitis in experimental models. Results Our findings reveal that PKD signaling is required for NF-κB activation/inflammation, intracellular zymogen activation, and acinar cell necrosis in rodent experimental pancreatitis. Novel small-molecule PKD inhibitors attenuate the severity of pancreatitis in both in vitro and in vivo experimental models. Further, this review emphasizes our latest advances in the therapeutic application of PKD inhibitors to experimental pancreatitis after the initiation of pancreatitis. Conclusions These novel findings suggest that PKD signaling is a necessary modulator in key initiating pathobiologic processes of pancreatitis, and that it constitutes a novel therapeutic target for treatments of this disorder. PMID:26879861

  19. TOR signalling in plants.

    PubMed

    Rexin, Daniel; Meyer, Christian; Robaglia, Christophe; Veit, Bruce

    2015-08-15

    Although the eukaryotic TOR (target of rapamycin) kinase signalling pathway has emerged as a key player for integrating nutrient-, energy- and stress-related cues with growth and metabolic outputs, relatively little is known of how this ancient regulatory mechanism has been adapted in higher plants. Drawing comparisons with the substantial knowledge base around TOR kinase signalling in fungal and animal systems, functional aspects of this pathway in plants are reviewed. Both conserved and divergent elements are discussed in relation to unique aspects associated with an autotrophic mode of nutrition and adaptive strategies for multicellular development exhibited by plants. © 2015 Authors; published by Portland Press Limited.

  20. Noninvasive vital signal monitoring

    NASA Astrophysics Data System (ADS)

    Wang, Zenan; Chee, Jonny; Chua, Kok Poo; Chen, ZhouDe

    2010-05-01

    Vital signals of patients, such as heart rate, temperature and movement are crucial to monitor patients in hospital. Current heart rate measurement is obtained by using Electrocardiograph, which normally applies electrodes to the patient's body. As electrodes are extremely uncomfortable to ware and hinder patient's movement, a non-invasive vital signal-monitoring device will be a better solution. Similar to Electrocardiograph, the device detects the voltage difference across the heart by using concept of capacitance, which can be obtained by two conductive fiber sewing on the bed sheet. Simultaneous temperature reading can also be detected by using surface mounted temperature sensor. This paper will mainly focus on the heart rate monitoring.

  1. Physiological Signal Conditioner

    NASA Technical Reports Server (NTRS)

    Friedericks, C.

    1999-01-01

    Sensors 2000! is developing a Physiological Signal Conditioner (PSC) for monitoring of astronauts in the ISS Human Research Facility. The PSC is battery powered and worn by the crew. The Engineering Development Unit (PSC EDU) and the form-and-fit PSC Tooling Model will be displayed along with associated graphics and text explanations. Results of a recent advanced PSC-2 feasibility study will be presented. The presentation will stimulate discussion of the functional capabilities of a wireless, crew worn Physiological Signal Conditioner. Application of advanced technology to meet the conflicting demands of size, power, and functional capability will be of interest.

  2. Universal signal conditioning amplifier

    NASA Technical Reports Server (NTRS)

    Larson, William E.; Hallberg, Carl; Medelius, Pedro J.

    1994-01-01

    Engineers at NASA's Kennedy Space Center have designed a signal conditioning amplifier which automatically matches itself to almost any kind of transducer. The product, called Universal Signal Conditioning Amplifier (USCA), uses state-of-the-art technologies to deliver high accuracy measurements. USCA's features which can be either programmable or automated include: voltage, current, or pulsed excitation, unlimited resolution gain, digital filtering and both analog and digital output. USCA will be used at Kennedy Space Center's launch pads for environmental measurements such as vibrations, strains, temperatures and overpressures. USCA is presently being commercialized through a co-funded agreement between NASA, the State of Florida, and Loral Test and Information Systems, Inc.

  3. Multichannel signal enhancement

    DOEpatents

    Lewis, Paul S.

    1990-01-01

    A mixed adaptive filter is formulated for the signal processing problem where desired a priori signal information is not available. The formulation generates a least squares problem which enables the filter output to be calculated directly from an input data matrix. In one embodiment, a folded processor array enables bidirectional data flow to solve the recursive problem by back substitution without global communications. In another embodiment, a balanced processor array solves the recursive problem by forward elimination through the array. In a particular application to magnetoencephalography, the mixed adaptive filter enables an evoked response to an auditory stimulus to be identified from only a single trial.

  4. Array signal processing

    SciTech Connect

    Haykin, S.; Justice, J.H.; Owsley, N.L.; Yen, J.L.; Kak, A.C.

    1985-01-01

    This is the first book to be devoted completely to array signal processing, a subject that has become increasingly important in recent years. The book consists of six chapters. Chapter 1, which is introductory, reviews some basic concepts in wave propagation. The remaining five chapters deal with the theory and applications of array signal processing in (a) exploration seismology, (b) passive sonar, (c) radar, (d) radio astronomy, and (e) tomographic imaging. The various chapters of the book are self-contained. The book is written by a team of five active researchers, who are specialists in the individual fields covered by the pertinent chapters.

  5. 29 CFR 1926.1422 - Signals-hand signal chart.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 8 2014-07-01 2014-07-01 false Signals-hand signal chart. 1926.1422 Section 1926.1422 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION... Construction § 1926.1422 Signals—hand signal chart. Hand signal charts must be either posted on the...

  6. 29 CFR 1926.1422 - Signals-hand signal chart.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 8 2012-07-01 2012-07-01 false Signals-hand signal chart. 1926.1422 Section 1926.1422 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION... Construction § 1926.1422 Signals—hand signal chart. Hand signal charts must be either posted on the...

  7. 29 CFR 1926.1422 - Signals-hand signal chart.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 8 2011-07-01 2011-07-01 false Signals-hand signal chart. 1926.1422 Section 1926.1422 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION... Construction § 1926.1422 Signals—hand signal chart. Hand signal charts must be either posted on the...

  8. 29 CFR 1926.1422 - Signals-hand signal chart.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 8 2013-07-01 2013-07-01 false Signals-hand signal chart. 1926.1422 Section 1926.1422 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION... Construction § 1926.1422 Signals—hand signal chart. Hand signal charts must be either posted on the...

  9. Contextual signaling in cancer.

    PubMed

    Smithson, Laura J; Anastasaki, Corina; Chen, Ran; Toonen, Joseph A; Williams, Sidney B; Gutmann, David H

    2016-10-01

    The formation and maintenance of an organism are highly dependent on the orderly control of cell growth, differentiation, death, and migration. These processes are tightly regulated by signaling cascades in which a limited number of molecules dictate these cellular events. While these signaling pathways are highly conserved across species and cell types, the functional outcomes that result from their engagement are specified by the context in which they are activated. Using the Neurofibromatosis type 1 (NF1) cancer predisposition syndrome as an illustrative platform, we discuss how NF1/RAS signaling can create functional diversity at multiple levels (molecular, cellular, tissue, and genetic/genomic). As such, the ability of related molecules (e.g., K-RAS, H-RAS) to activate distinct effectors, as well as cell type- and tissue-specific differences in molecular composition and effector engagement, generate numerous unique functional effects. These variations, coupled with a multitude of extracellular cues and genomic/genetic changes that each modify the innate signaling properties of the cell, enable precise control of cellular physiology in both health and disease. Understanding these contextual influences is important when trying to dissect the underlying pathogenic mechanisms of cancer relevant to molecularly-targeted therapeutics.

  10. Communication Signals in Lizards.

    ERIC Educational Resources Information Center

    Carpenter, Charles C.

    1983-01-01

    Discusses mechanisms and functional intent of visual communication signals in iguanid/agamid lizards. Demonstrated that lizards communicate with each other by using pushups and head nods and that each species does this in its own way, conveying different types of information. (JN)

  11. Signal processing in SETI.

    PubMed

    Cullers, D K; Linscott, I R; Oliver, B M

    1985-11-01

    The development of a multi-channel spectrum analyzer (MCSA) for the SETI program is described. The spectrum analyzer is designed for both all-sky surveys and targeted searches. The mechanisms of the MCSA are explained and a diagram is provided. Detection of continuous wave signals, pulses, and patterns is examined.

  12. Communication Signals in Lizards.

    ERIC Educational Resources Information Center

    Carpenter, Charles C.

    1983-01-01

    Discusses mechanisms and functional intent of visual communication signals in iguanid/agamid lizards. Demonstrated that lizards communicate with each other by using pushups and head nods and that each species does this in its own way, conveying different types of information. (JN)

  13. Signaling by Sensory Receptors

    PubMed Central

    Julius, David; Nathans, Jeremy

    2012-01-01

    Sensory systems detect small molecules, mechanical perturbations, or radiation via the activation of receptor proteins and downstream signaling cascades in specialized sensory cells. In vertebrates, the two principal categories of sensory receptors are ion channels, which mediate mechanosensation, thermosensation, and acid and salt taste; and G-protein-coupled receptors (GPCRs), which mediate vision, olfaction, and sweet, bitter, and umami tastes. GPCR-based signaling in rods and cones illustrates the fundamental principles of rapid activation and inactivation, signal amplification, and gain control. Channel-based sensory systems illustrate the integration of diverse modulatory signals at the receptor, as seen in the thermosensory/pain system, and the rapid response kinetics that are possible with direct mechanical gating of a channel. Comparisons of sensory receptor gene sequences reveal numerous examples in which gene duplication and sequence divergence have created novel sensory specificities. This is the evolutionary basis for the observed diversity in temperature- and ligand-dependent gating among thermosensory channels, spectral tuning among visual pigments, and odorant binding among olfactory receptors. The coding of complex external stimuli by a limited number of sensory receptor types has led to the evolution of modality-specific and species-specific patterns of retention or loss of sensory information, a filtering operation that selectively emphasizes features in the stimulus that enhance survival in a particular ecological niche. The many specialized anatomic structures, such as the eye and ear, that house primary sensory neurons further enhance the detection of relevant stimuli. PMID:22110046

  14. Hybrid ECG signal conditioner

    NASA Technical Reports Server (NTRS)

    Rinard, G. A.; Steffen, D. A.; Sturm, R. E.

    1979-01-01

    Circuit with high common-mode rejection has ability to filter and amplify accepted analog electrocardiogram (ECG) signals of varying amplitude, shape, and polarity. In addition, low power circuit develops standardized pulses that can be counted and averaged by heart/breath rate processor.

  15. Multipath signal model development

    NASA Technical Reports Server (NTRS)

    Ghais, A. F.; Wachsman, R. H.

    1970-01-01

    The development and use of mathematical models of signals received through the multipath environmental of a TDRS-to-user spacecraft link and vice versa are discussed. The TDRS (tracking and data relay satellite) will be in synchronous orbit. The user spacecraft will be in a low altitude orbit between 200 and 4000 km.

  16. Chondrodysplasias and TGFβ signaling

    PubMed Central

    Le Goff, Carine; Cormier-Daire, Valerie

    2015-01-01

    Human chondrodysplasias are a group of conditions that affect the cartilage. This review is focused on the involvement of transforming growth factor-β signaling in a group of chondrodysplasias, entitled acromelic dysplasia, characterized by short stature, short hands and restricted joint mobility. PMID:25798233

  17. Signals: Applying Academic Analytics

    ERIC Educational Resources Information Center

    Arnold, Kimberly E.

    2010-01-01

    Academic analytics helps address the public's desire for institutional accountability with regard to student success, given the widespread concern over the cost of higher education and the difficult economic and budgetary conditions prevailing worldwide. Purdue University's Signals project applies the principles of analytics widely used in…

  18. Auxin signal transduction.

    PubMed

    Hagen, Gretchen

    2015-01-01

    The plant hormone auxin (indole-3-acetic acid, IAA) controls growth and developmental responses throughout the life of a plant. A combination of molecular, genetic and biochemical approaches has identified several key components involved in auxin signal transduction. Rapid auxin responses in the nucleus include transcriptional activation of auxin-regulated genes and degradation of transcriptional repressor proteins. The nuclear auxin receptor is an integral component of the protein degradation machinery. Although auxin signalling in the nucleus appears to be short and simple, recent studies indicate that there is a high degree of diversity and complexity, largely due to the existence of multigene families for each of the major molecular components. Current studies are attempting to identify interacting partners among these families, and to define the molecular mechanisms involved in the interactions. Future goals are to determine the levels of regulation of the key components of the transcriptional complex, to identify higher-order complexes and to integrate this pathway with other auxin signal transduction pathways, such as the pathway that is activated by auxin binding to a different receptor at the outer surface of the plasma membrane. In this case, auxin binding triggers a signal cascade that affects a number of rapid cytoplasmic responses. Details of this pathway are currently under investigation. © 2015 Authors; published by Portland Press Limited.

  19. Signals: Applying Academic Analytics

    ERIC Educational Resources Information Center

    Arnold, Kimberly E.

    2010-01-01

    Academic analytics helps address the public's desire for institutional accountability with regard to student success, given the widespread concern over the cost of higher education and the difficult economic and budgetary conditions prevailing worldwide. Purdue University's Signals project applies the principles of analytics widely used in…

  20. Synergistic signals in the environment.

    PubMed Central

    Arnold, S F; McLachlan, J A

    1996-01-01

    Numerous endogenous signals (such as hormones and growth factors) or environmental signals (including chemicals or temperature) contribute to determining the overall biological response produced by cells. Some combinations of endogenous or environmental signals produce synergistic activity. This commentary examines the different types of interactions between signals that contribute to synergy at the biological level. Images Figure 1. PMID:8930538

  1. Aural perception of NDE signals

    SciTech Connect

    Light, G.M.; Holt, A.E.; Polk, K.D.; Godwin, J.G.; Clayton, W.T.

    1994-12-31

    During nondestructive evaluation (NDE) of a material, the inspection signals are received typically by an NDE instrument. These signals usually are displayed electronically for visual interpretation. Work has been done to convert these signals into aural (audible) signals with the intent to enhance the accuracy of evaluation through the use of two senses (ears and eyes) instead of one. This paper describes auralization of ultrasonic NDE testing signals to improve characterization and evaluation of materials.

  2. Signal processor chip implementation

    NASA Astrophysics Data System (ADS)

    Beraud, J. P.

    1985-03-01

    Advances in technology have made it now possible to integrate very large microprocessors on a single chip. Two basic design methodologies are available, including gate array and custom design. The present paper is concerned with a signal processor (SP) chip which is based on a mixture of the two technologies. Involved is a high-density chip which requires little manual effort for its production. The SP is characterized by separate instruction and data memories. The SP consists of three main parts which operate simultaneously. These parts include the sequencer, the address generator, and the computer portion. The chip comprises a library of predesigned building blocks. Attention is given to a signal processor block diagram, the basic TTL gate, a two-input master-slave latch, the physical library, aspects of logical design, the multiplier basic cell and adder line organization, and physical design methodology.

  3. Signals and Responses

    PubMed Central

    Lee, Angie

    2006-01-01

    The nitrogen-fixing symbiosis between bacteria in the family Rhizobiaceae and members of the legume family (Fabaceae) has been well studied, particularly from the perspective of the early signaling and recognition events. Recent studies of non-nodulating legume mutants have resulted in the identification of a number of genes that are responsive to signal molecules from the bacteria. However, a second group of nodule-forming bacteria, completely unrelated to the Rhizobiaceae, which are α-Proteobacteria, has been discovered. These bacteria belong to the β-Proteobacteria and have been designated β-rhizobia to distinguish them from the better-known α-rhizobia. Here, we review what is known in this economically important symbiosis about the interaction between legumes and α-rhizobia, and we incorporate information, where known, about the β-rhizobia. PMID:19521481

  4. Microglia Ontology and Signaling

    PubMed Central

    ElAli, Ayman; Rivest, Serge

    2016-01-01

    Microglia constitute the powerhouse of the innate immune system in the brain. It is now widely accepted that they are monocytic-derived cells that infiltrate the developing brain at the early embryonic stages, and acquire a resting phenotype characterized by the presence of dense branching processes, called ramifications. Microglia use these dynamic ramifications as sentinels to sense and detect any occurring alteration in brain homeostasis. Once a danger signal is detected, such as molecular factors associated to brain damage or infection, they get activated by acquiring a less ramified phenotype, and mount adequate responses that range from phagocyting cell debris to secreting inflammatory and trophic factors. Here, we review the origin of microglia and we summarize the main molecular signals involved in controlling their function under physiological conditions. In addition, their implication in the pathogenesis of multiple sclerosis and stress is discussed. PMID:27446922

  5. Strigolactones: promising plant signals.

    PubMed

    Gomez-Roldan, Victoria; Roux, Christophe; Girard, Daniel; Bécard, Guillaume; Puech-Pagés, Virginie

    2007-05-01

    As obligate biotrophic symbionts, Arbuscular Mycorrhizal (AM) fungi must efficiently recognize their host plant to insure their survival and complete their life cycle. Recent works have shown that some root secreted molecules, the strigolactones, activate the presymbiotic growth of AM fungi at extremely low concentrations. These compounds, derived from carotenoid biosynthesis, induce the mitochondrial metabolism of the fungus. The hypothesis that strigolactones are important plant recognition signals for AM fungi was further supported in this study by using maize seedlings treated with fluridone, an upstream inhibitor of the carotenoid metabolism. We showed that mycorrhization of the treated seedlings was significantly reduced, but restored by the addition of GR24, a strigolactone analogue. Similar results were obtained with the y9 mutant of maize defective in an upstream step of carotenoid synthesis. These data provide additional evidence that strigolactones may be essential symbiotic signals for the establishment of AM symbiosis.

  6. JAZing up jasmonate signaling.

    PubMed

    Staswick, Paul E

    2008-02-01

    Recent discoveries show that jasmonate ZIM-domain (JAZ) transcriptional repressors are key regulators of jasmonate hormonal response. Jasmonate promotes interaction between JAZ proteins and the SCF(COI1) ubiquitin ligase, leading to JAZ degradation via the 26S proteasome in Arabidopsis thaliana. Elimination of JAZ repressors then frees the MYC2 transcription factor to stimulate jasmonate-dependent gene expression. Although jasmonic acid and methyl jasmonate were thought to be key regulators of jasmonate responses, they were ineffective in promoting SCF(COI1)-JAZ interaction and it is the isoleucine conjugate of jasmonic acid that acts in this signal transduction pathway. The discovery of JAZ transcriptional regulators greatly advances our understanding of how jasmonate signaling regulates plant growth and response to the environment.

  7. Tailpulse signal generator

    DOEpatents

    Baker, John; Archer, Daniel E.; Luke, Stanley John; Decman, Daniel J.; White, Gregory K.

    2009-06-23

    A tailpulse signal generating/simulating apparatus, system, and method designed to produce electronic pulses which simulate tailpulses produced by a gamma radiation detector, including the pileup effect caused by the characteristic exponential decay of the detector pulses, and the random Poisson distribution pulse timing for radioactive materials. A digital signal process (DSP) is programmed and configured to produce digital values corresponding to pseudo-randomly selected pulse amplitudes and pseudo-randomly selected Poisson timing intervals of the tailpulses. Pulse amplitude values are exponentially decayed while outputting the digital value to a digital to analog converter (DAC). And pulse amplitudes of new pulses are added to decaying pulses to simulate the pileup effect for enhanced realism in the simulation.

  8. Wnt signaling in cnidarians.

    PubMed

    Holstein, Thomas W

    2008-01-01

    Cnidarians are an ancient group of animals at the base of metazoan evolution. They exhibit a simple body plan with only one well-defined body axis and a small number of cell types. Cnidarians are also well known for their enormous regeneration capacity. Recent work in the freshwater polyp Hydra and in the sea anemone Nematostella has identified an unexpectedly high level of genetic complexity of wnt genes. Canonical Wnt signaling acts in pattern formation and regeneration of Hydra and also in gastrulation and early embryogenesis of Nematostella. Vertebrate-specific Wnt-antagonists were also identified from cnidarians and exhibit similar conserved functions. The simple cnidarian body plan and the now available genomes from Hydra and Nematostella, together with new functional approaches, make these animals an attractive model for studying the basic functions of canonical and non-canonical Wnt signaling.

  9. Pituitary Somatostatin Receptor Signaling

    PubMed Central

    Ben-Shlomo, Anat; Melmed, Shlomo

    2010-01-01

    Somatostatin (SRIF) is a major regulator of pituitary function, mostly inhibiting hormone secretion and to a lesser extent pituitary cell growth. Five SRIF receptor subtypes (SSTR1–5) are ubiquitously expressed G-protein coupled receptors. In the pituitary, SSTR1, SSTR2, SSTR3 and SSTR5 are expressed, with SSTR2 and SSTR5 predominating. As new SRIF-analogs have recently been introduced for treatment of pituitary disease, we evaluate the current knowledge of cell-specific pituitary SRIF receptor signaling and highlight areas of future research for comprehensive understanding of these mechanisms. Elucidating pituitary SRIF receptor signaling enables understanding of pituitary hormone secretion and cell growth, and also points to future therapeutic development for pituitary disorders. PMID:20149677

  10. Growth hormone signaling pathways.

    PubMed

    Carter-Su, Christin; Schwartz, Jessica; Argetsinger, Lawrence S

    2016-06-01

    Over 20years ago, our laboratory showed that growth hormone (GH) signals through the GH receptor-associated tyrosine kinase JAK2. We showed that GH binding to its membrane-bound receptor enhances binding of JAK2 to the GHR, activates JAK2, and stimulates tyrosyl phosphorylation of both JAK2 and GHR. The activated JAK2/GHR complex recruits a variety of signaling proteins, thereby initiating multiple signaling pathways and cellular responses. These proteins and pathways include: 1) Stat transcription factors implicated in the expression of multiple genes, including the gene encoding insulin-like growth factor 1; 2) Shc adapter proteins that lead to activation of the grb2-SOS-Ras-Raf-MEK-ERK1,2 pathway; 3) insulin receptor substrate proteins implicated in the phosphatidylinositol-3-kinase and Akt pathway; 4) signal regulatory protein α, a transmembrane scaffold protein that recruits proteins including the tyrosine phosphatase SHP2; and 5) SH2B1, a scaffold protein that can activate JAK2 and enhance GH regulation of the actin cytoskeleton. Our recent work has focused on the function of SH2B1. We have shown that SH2B1β is recruited to and phosphorylated by JAK2 in response to GH. SH2B1 localizes to the plasma membrane, cytoplasm and focal adhesions; it also cycles through the nucleus. SH2B1 regulates the actin cytoskeleton and promotes GH-dependent motility of RAW264.7 macrophages. Mutations in SH2B1 have been found in humans exhibiting severe early-onset childhood obesity and insulin resistance. These mutations impair SH2B1 enhancement of GH-induced macrophage motility. As SH2B1 is expressed ubiquitously and is also recruited to a variety of receptor tyrosine kinases, our results raise the possibility that effects of SH2B1 on the actin cytoskeleton in various cell types, including neurons, may play a role in regulating body weight.

  11. Complex Auditory Signals

    DTIC Science & Technology

    1988-09-01

    Journal of the Acoustical Society of America, 56, 1835-1847. Sachs, M. B., and Young, E.ID. (1979). Encoding of steady-state vowels in the auditory nerve...amplitude to the amplitude of that component of the standard in decibels . If the signal amplitude is one-eighth the amplitude of the com- ponent of the...Isolated pure tone appears to have little to do with how we recognize differences between vowels or broadband consonants. The simplicity of

  12. Strain Gage Signal Interpretation.

    DTIC Science & Technology

    1986-02-01

    blades and vanes in many engines have been collected, played back and examined. The engine types encompass GE’s stable of turbine engines from the small...aeromechanical engineer . 1.3 SUMMARY OF RESULTS Strain gage signals from vibrating rotor blades and vanes were collected, examined, classified, and generalized...turboprops, to turbojets and to the large high bypass turbofan engines . Test conditions include all the phases that are investigated

  13. Signal Acquisition Using AXIe

    NASA Astrophysics Data System (ADS)

    Narciso, Steven J.

    2011-08-01

    An emerging test and measurement standard called AXIe, AdvancedTCA extensions for Instrumentation, is expected to find wide acceptance within the Physics community as it offers many benefits to applications including shock, plasma, particle and nuclear physics. It is expected that many COTS (commercial off-the-shelf) signal conditioning, acquisition and processing modules will become available from a range of different suppliers. AXIe uses AdvancedTCA® as its basis, but then levers test and measurement industry standards such as PXI, IVI, and LXI to facilitate cooperation and plug-and-play interoperability between COTS instrument suppliers. AXIe's large board footprint and power allows high density in a 19" rack, enabling the development of high-performance signal conditioning, analog-to-digital conversion, and data processing, while offering channel count scalability inherent in modular systems. Synchronization between modules is flexible and provided by two triggering structures: a parallel trigger bus, and radially-distributed, time-matched point-to-point trigger lines. Inter-module communication is also provided with an adjacent module local bus allowing data transfer to 600 Gbits/s in each direction, for example between a front-end digitizer and DSP. AXIe allows embedding high performance computing and a range of COTS AdvancedTCA® computer blades are currently available that provide low cost alternatives to the development of custom signal processing modules. The availability of both LAN and PCI Express allow interconnection between modules, as well as industry-standard high-performance data paths to external host computer systems. AXIe delivers a powerful environment for custom module devel opment. As in the case of VXIbus and PXI before it, commercial development kits are expected to be available. This paper will give an overview of the architectural elements of AXIe 1.0, the compatibility model with AdvancedTCA, and signal acquisition performance of many

  14. Automatic Seismic Signal Processing

    DTIC Science & Technology

    1982-02-04

    CATALOG NUMBER 4. TITLE (end Sublitle) S. TYPE O REPORT & PERIOD COVERED FINAL TECHNICAL REPORT - ROUTINE AUTOM!ATIC SEISMIC ANALYSIS TECHNICAL PACKAGE 6...Seismic Analysis Package ARPA Order Number: 4199 Name of Contractor: ENSCO, Inc. 4 - Contract Number: F086 06-80-C-0021 Effective Date of Contract: 10...developed and demonstrated. This timing detector algorithm times the start time of signals and their envelope peaks. It was designed to measure the size

  15. RASSP signal processing architectures

    NASA Astrophysics Data System (ADS)

    Shirley, Fred; Bassett, Bob; Letellier, J. P.

    1995-06-01

    The rapid prototyping of application specific signal processors (RASSP) program is an ARPA/tri-service effort to dramatically improve the process by which complex digital systems, particularly embedded signal processors, are specified, designed, documented, manufactured, and supported. The domain of embedded signal processing was chosen because it is important to a variety of military and commercial applications as well as for the challenge it presents in terms of complexity and performance demands. The principal effort is being performed by two major contractors, Lockheed Sanders (Nashua, NH) and Martin Marietta (Camden, NJ). For both, improvements in methodology are to be exercised and refined through the performance of individual 'Demonstration' efforts. The Lockheed Sanders' Demonstration effort is to develop an infrared search and track (IRST) processor. In addition, both contractors' results are being measured by a series of externally administered (by Lincoln Labs) six-month Benchmark programs that measure process improvement as a function of time. The first two Benchmark programs are designing and implementing a synthetic aperture radar (SAR) processor. Our demonstration team is using commercially available VME modules from Mercury Computer to assemble a multiprocessor system scalable from one to hundreds of Intel i860 microprocessors. Custom modules for the sensor interface and display driver are also being developed. This system implements either proprietary or Navy owned algorithms to perform the compute-intensive IRST function in real time in an avionics environment. Our Benchmark team is designing custom modules using commercially available processor ship sets, communication submodules, and reconfigurable logic devices. One of the modules contains multiple vector processors optimized for fast Fourier transform processing. Another module is a fiberoptic interface that accepts high-rate input data from the sensors and provides video-rate output data to a

  16. Biological Information Signal Processor

    NASA Technical Reports Server (NTRS)

    Chow, Edward T.; Peterson, John C.; Yoo, Michael M.

    1993-01-01

    Biological Information Signal Processor (BISP) is computing system analyzing data on deoxyribonucleic acid (DNA) sequences for molecular genetic analysis. Includes coprocessors, specialized microprocessors complementing present and future computers by performing rapidly most-time-consuming DNA-sequence-analyzing functions, establishing relationships (alignments) between both global sequences and defining patterns in multiple sequences. Also includes state-of-art software and data-base systems on both conventional and parallel computer systems to augment analytical abilities of developmental coprocessors.

  17. Multipoint multirate signal processing

    NASA Astrophysics Data System (ADS)

    Claypoole, Roger L., Jr.

    1994-12-01

    This thesis provides a fundamentally new, systematic study of multipoint multirate signal processing systems. The multipoint multirate operators are analyzed via equivalent circuits comprised entirely of conventional multirate operators. Interconnections of the operators are demonstrated, and the multipoint noble identities are derived. The multipoint polyphase representation is presented, and the M channel multipoint multirate system with vector length N is presented as an MN channel multipoint polyphase system. The conditions sufficient for perfect reconstruction in the multipoint multirate system are derived. These conditions constrain the multipoint filter banks to be composed of comb filters generated from paraunitary sets of conventional filters. The perfect reconstruction multipoint multirate system is then combined with the multiresolution wavelet decomposition to form the generalized wavelet decomposition with varying vector decimation length at each level. The generalized wavelet decomposition is used as an algorithm to redistribute the energy of a signal throughout the levels of the decomposition. It is shown that, for band pass and high pass signals, significant improvements can be made in the energy distribution. It is recommended that this algorithm be studied as a front end to a vector quantizer for data compression applications.

  18. Adaptive Signal Processing Testbed

    NASA Astrophysics Data System (ADS)

    Parliament, Hugh A.

    1991-09-01

    The design and implementation of a system for the acquisition, processing, and analysis of signal data is described. The initial application for the system is the development and analysis of algorithms for excision of interfering tones from direct sequence spread spectrum communication systems. The system is called the Adaptive Signal Processing Testbed (ASPT) and is an integrated hardware and software system built around the TMS320C30 chip. The hardware consists of a radio frequency data source, digital receiver, and an adaptive signal processor implemented on a Sun workstation. The software components of the ASPT consists of a number of packages including the Sun driver package; UNIX programs that support software development on the TMS320C30 boards; UNIX programs that provide the control, user interaction, and display capabilities for the data acquisition, processing, and analysis components of the ASPT; and programs that perform the ASPT functions including data acquisition, despreading, and adaptive filtering. The performance of the ASPT system is evaluated by comparing actual data rates against their desired values. A number of system limitations are identified and recommendations are made for improvements.

  19. Plant peptide hormone signalling.

    PubMed

    Motomitsu, Ayane; Sawa, Shinichiro; Ishida, Takashi

    2015-01-01

    The ligand-receptor-based cell-to-cell communication system is one of the most important molecular bases for the establishment of complex multicellular organisms. Plants have evolved highly complex intercellular communication systems. Historical studies have identified several molecules, designated phytohormones, that function in these processes. Recent advances in molecular biological analyses have identified phytohormone receptors and signalling mediators, and have led to the discovery of numerous peptide-based signalling molecules. Subsequent analyses have revealed the involvement in and contribution of these peptides to multiple aspects of the plant life cycle, including development and environmental responses, similar to the functions of canonical phytohormones. On the basis of this knowledge, the view that these peptide hormones are pivotal regulators in plants is becoming increasingly accepted. Peptide hormones are transcribed from the genome and translated into peptides. However, these peptides generally undergo further post-translational modifications to enable them to exert their function. Peptide hormones are expressed in and secreted from specific cells or tissues. Apoplastic peptides are perceived by specialized receptors that are located at the surface of target cells. Peptide hormone-receptor complexes activate intracellular signalling through downstream molecules, including kinases and transcription factors, which then trigger cellular events. In this chapter we provide a comprehensive summary of the biological functions of peptide hormones, focusing on how they mature and the ways in which they modulate plant functions.

  20. Space-Variant Processing Using Phase Codes and Fourier-Plane Sampling Techniques,

    DTIC Science & Technology

    1980-06-01

    also established. A technique for fabricating a two dimensional phase mask using Dichromated gelatin is described in Appendix G. In the following two...fabricating phase masks using dichromated gelatin is discussed in Appen- dix G. Additional work needs to be done in this area to perfect this fabrication...89-97. [22] L. H. Lin, "Hologram formation in hardened dichromated gelatin films," Applied Optics, 8, 963 (1969). (23] C. D. Leonard, and B. D

  1. FORCE2: A state-of-the-art two-phase code for hydrodynamic calculations

    SciTech Connect

    Ding, Jianmin; Lyczkowski, R.W. ); Burge, S.W. . Research Center)

    1993-02-01

    A three-dimensional computer code for two-phase flow named FORCE2 has been developed by Babcock and Wilcox (B W) in close collaboration with Argonne National Laboratory (ANL). FORCE2 is capable of both transient as well as steady-state simulations. This Cartesian coordinates computer program is a finite control volume, industrial grade and quality embodiment of the pilot-scale FLUFIX/MOD2 code and contains features such as three-dimensional blockages, volume and surface porosities to account for various obstructions in the flow field, and distributed resistance modeling to account for pressure drops caused by baffles, distributor plates and large tube banks. Recently computed results demonstrated the significance of and necessity for three-dimensional models of hydrodynamics and erosion. This paper describes the process whereby ANL's pilot-scale FLUFIX/MOD2 models and numerics were implemented into FORCE2. A description of the quality control to assess the accuracy of the new code and the validation using some of the measured data from Illinois Institute of Technology (UT) and the University of Illinois at Urbana-Champaign (UIUC) are given. It is envisioned that one day, FORCE2 with additional modules such as radiation heat transfer, combustion kinetics and multi-solids together with user-friendly pre- and post-processor software and tailored for massively parallel multiprocessor shared memory computational platforms will be used by industry and researchers to assist in reducing and/or eliminating the environmental and economic barriers which limit full consideration of coal, shale and biomass as energy sources, to retain energy security, and to remediate waste and ecological problems.

  2. FORCE2: A state-of-the-art two-phase code for hydrodynamic calculations

    SciTech Connect

    Ding, Jianmin; Lyczkowski, R.W.; Burge, S.W.

    1993-02-01

    A three-dimensional computer code for two-phase flow named FORCE2 has been developed by Babcock and Wilcox (B & W) in close collaboration with Argonne National Laboratory (ANL). FORCE2 is capable of both transient as well as steady-state simulations. This Cartesian coordinates computer program is a finite control volume, industrial grade and quality embodiment of the pilot-scale FLUFIX/MOD2 code and contains features such as three-dimensional blockages, volume and surface porosities to account for various obstructions in the flow field, and distributed resistance modeling to account for pressure drops caused by baffles, distributor plates and large tube banks. Recently computed results demonstrated the significance of and necessity for three-dimensional models of hydrodynamics and erosion. This paper describes the process whereby ANL`s pilot-scale FLUFIX/MOD2 models and numerics were implemented into FORCE2. A description of the quality control to assess the accuracy of the new code and the validation using some of the measured data from Illinois Institute of Technology (UT) and the University of Illinois at Urbana-Champaign (UIUC) are given. It is envisioned that one day, FORCE2 with additional modules such as radiation heat transfer, combustion kinetics and multi-solids together with user-friendly pre- and post-processor software and tailored for massively parallel multiprocessor shared memory computational platforms will be used by industry and researchers to assist in reducing and/or eliminating the environmental and economic barriers which limit full consideration of coal, shale and biomass as energy sources, to retain energy security, and to remediate waste and ecological problems.

  3. Geometric phase coded metasurface: from polarization dependent directive electromagnetic wave scattering to diffusion-like scattering

    NASA Astrophysics Data System (ADS)

    Chen, Ke; Feng, Yijun; Yang, Zhongjie; Cui, Li; Zhao, Junming; Zhu, Bo; Jiang, Tian

    2016-10-01

    Ultrathin metasurface compromising various sub-wavelength meta-particles offers promising advantages in controlling electromagnetic wave by spatially manipulating the wavefront characteristics across the interface. The recently proposed digital coding metasurface could even simplify the design and optimization procedures due to the digitalization of the meta-particle geometry. However, current attempts to implement the digital metasurface still utilize several structural meta-particles to obtain certain electromagnetic responses, and requiring time-consuming optimization especially in multi-bits coding designs. In this regard, we present herein utilizing geometric phase based single structured meta-particle with various orientations to achieve either 1-bit or multi-bits digital metasurface. Particular electromagnetic wave scattering patterns dependent on the incident polarizations can be tailored by the encoded metasurfaces with regular sequences. On the contrast, polarization insensitive diffusion-like scattering can also been successfully achieved by digital metasurface encoded with randomly distributed coding sequences leading to substantial suppression of backward scattering in a broadband microwave frequency. The proposed digital metasurfaces provide simple designs and reveal new opportunities for controlling electromagnetic wave scattering with or without polarization dependence.

  4. Thermal Coherence Tomography Using Match Filter Binary Phase Coded Diffusion Waves

    NASA Astrophysics Data System (ADS)

    Tabatabaei, Nima; Mandelis, Andreas

    2011-10-01

    Energy transport in diffusion-wave fields is gradient-driven and therefore diffuse, yielding depth-integrated responses with poor axial resolution. Using matched-filter principles, we propose a methodology enabling these parabolic diffusion-wave energy fields to exhibit energy localization akin to propagating hyperbolic wave fields. This not only improves axial resolution but also allows for deconvolution of individual responses of superposed axially discrete sources, opening a new field of depth-resolved subsurface thermal coherence tomography using diffusion waves.

  5. Geometric phase coded metasurface: from polarization dependent directive electromagnetic wave scattering to diffusion-like scattering.

    PubMed

    Chen, Ke; Feng, Yijun; Yang, Zhongjie; Cui, Li; Zhao, Junming; Zhu, Bo; Jiang, Tian

    2016-10-24

    Ultrathin metasurface compromising various sub-wavelength meta-particles offers promising advantages in controlling electromagnetic wave by spatially manipulating the wavefront characteristics across the interface. The recently proposed digital coding metasurface could even simplify the design and optimization procedures due to the digitalization of the meta-particle geometry. However, current attempts to implement the digital metasurface still utilize several structural meta-particles to obtain certain electromagnetic responses, and requiring time-consuming optimization especially in multi-bits coding designs. In this regard, we present herein utilizing geometric phase based single structured meta-particle with various orientations to achieve either 1-bit or multi-bits digital metasurface. Particular electromagnetic wave scattering patterns dependent on the incident polarizations can be tailored by the encoded metasurfaces with regular sequences. On the contrast, polarization insensitive diffusion-like scattering can also been successfully achieved by digital metasurface encoded with randomly distributed coding sequences leading to substantial suppression of backward scattering in a broadband microwave frequency. The proposed digital metasurfaces provide simple designs and reveal new opportunities for controlling electromagnetic wave scattering with or without polarization dependence.

  6. Episodic sequence memory is supported by a theta-gamma phase code

    PubMed Central

    Heusser, Andrew C.; Poeppel, David; Ezzyat, Youssef; Davachi, Lila

    2016-01-01

    The meaning we derive from our experiences is not a simple static extraction of the elements, but is largely based on the order in which those elements occur. Models propose that sequence encoding is supported by interactions between high and low frequency oscillations, such that elements within an experience are represented by neural cell assemblies firing at higher frequencies (i.e. gamma) and sequential order is coded by the specific timing of firing with respect to a lower frequency oscillation (i.e. theta). During episodic sequence memory formation in humans, we provide evidence that items in different sequence positions exhibit relatively greater gamma power along distinct phases of a theta oscillation. Furthermore, this segregation is related to successful temporal order memory. These results provide compelling evidence that memory for order, a core component of an episodic memory, capitalizes on the ubiquitous physiological mechanism of theta-gamma phase-amplitude coupling. PMID:27571010

  7. Geometric phase coded metasurface: from polarization dependent directive electromagnetic wave scattering to diffusion-like scattering

    PubMed Central

    Chen, Ke; Feng, Yijun; Yang, Zhongjie; Cui, Li; Zhao, Junming; Zhu, Bo; Jiang, Tian

    2016-01-01

    Ultrathin metasurface compromising various sub-wavelength meta-particles offers promising advantages in controlling electromagnetic wave by spatially manipulating the wavefront characteristics across the interface. The recently proposed digital coding metasurface could even simplify the design and optimization procedures due to the digitalization of the meta-particle geometry. However, current attempts to implement the digital metasurface still utilize several structural meta-particles to obtain certain electromagnetic responses, and requiring time-consuming optimization especially in multi-bits coding designs. In this regard, we present herein utilizing geometric phase based single structured meta-particle with various orientations to achieve either 1-bit or multi-bits digital metasurface. Particular electromagnetic wave scattering patterns dependent on the incident polarizations can be tailored by the encoded metasurfaces with regular sequences. On the contrast, polarization insensitive diffusion-like scattering can also been successfully achieved by digital metasurface encoded with randomly distributed coding sequences leading to substantial suppression of backward scattering in a broadband microwave frequency. The proposed digital metasurfaces provide simple designs and reveal new opportunities for controlling electromagnetic wave scattering with or without polarization dependence. PMID:27775064

  8. Code Inverse Filtering for Complete Sidelobe Removal in Binary Phase Coded Pulse Compression Systems

    DTIC Science & Technology

    2005-05-01

    Thus for the comparison presented in Table 1 either the FIR or the IIR approaches to range sidelobe suppression could be implemented with similar...sidelobe reduction filter design would be applicable. 8. CONCLUSIONS This paper has reviewed several techniques for reducing the range sidelobe levels...F.E.Nathanson, J.P.Reilly, and M.Cohen. Radar Design Principles, 2 ed., New York: McGraw-Hill, 1991. 3. O.Erikmats, " Range sidelobe elimination for

  9. [Interference Detection and Signal Quality Assessment of Pulse Signals].

    PubMed

    Zhang, Aihua; Wei, Fangyuan; Chou, Yongxin; Yang, Xiaohua

    2015-07-01

    Pulse signal contains a wealth of biological and pathological information. However, it is susceptible to the influence of various factors which results in poor signal quality, and causes the device to generate false alarms. First the pulse signals are processing into discrete symbols, and then compare the test signal with the pulse template by using Dynamic Time Warping (DTW) to get the threshold for which can be used to find the interference segment of the test signal. By analyzing the DTW distance of the pulse signal, we can get the interference degree of the signal, then the quality level of the plus signal can be defined by the relationship between the interference degree and quality of the signal. The 1 055 group pulse signals provided by MIMIC II physiological database are used to train and test the signal quality assessment algorithms, and compared with other existing algorithms. The results show that the algorithms can accurately detect interference segments in pulse signal and reflect the quality of it.

  10. The Hedgehog Signal Transduction Network

    PubMed Central

    Robbins, David J.; Fei, Dennis Liang; Riobo, Natalia A.

    2013-01-01

    Hedgehog (Hh) proteins regulate the development of a wide range of metazoan embryonic and adult structures, and disruption of Hh signaling pathways results in various human diseases. Here, we provide a comprehensive review of the signaling pathways regulated by Hh, consolidating data from a diverse array of organisms in a variety of scientific disciplines. Similar to the elucidation of many other signaling pathways, our knowledge of Hh signaling developed in a sequential manner centered on its earliest discoveries. Thus, our knowledge of Hh signaling has for the most part focused on elucidating the mechanism by which Hh regulates the Gli family of transcription factors, the so-called “canonical” Hh signaling pathway. However, in the past few years, numerous studies have shown that Hh proteins can also signal through Gli-independent mechanisms collectively referred to as “noncanonical” signaling pathways. Noncanonical Hh signaling is itself subdivided into two distinct signaling modules: (i) those not requiring Smoothened (Smo) and (ii) those downstream of Smo that do not require Gli transcription factors. Thus, Hh signaling is now proposed to occur through a variety of distinct context-dependent signaling modules that have the ability to crosstalk with one another to form an interacting, dynamic Hh signaling network. PMID:23074268

  11. Purinergic Signalling: Therapeutic Developments

    PubMed Central

    Burnstock, Geoffrey

    2017-01-01

    Purinergic signalling, i.e., the role of nucleotides as extracellular signalling molecules, was proposed in 1972. However, this concept was not well accepted until the early 1990’s when receptor subtypes for purines and pyrimidines were cloned and characterised, which includes four subtypes of the P1 (adenosine) receptor, seven subtypes of P2X ion channel receptors and 8 subtypes of the P2Y G protein-coupled receptor. Early studies were largely concerned with the physiology, pharmacology and biochemistry of purinergic signalling. More recently, the focus has been on the pathophysiology and therapeutic potential. There was early recognition of the use of P1 receptor agonists for the treatment of supraventricular tachycardia and A2A receptor antagonists are promising for the treatment of Parkinson’s disease. Clopidogrel, a P2Y12 antagonist, is widely used for the treatment of thrombosis and stroke, blocking P2Y12 receptor-mediated platelet aggregation. Diquafosol, a long acting P2Y2 receptor agonist, is being used for the treatment of dry eye. P2X3 receptor antagonists have been developed that are orally bioavailable and stable in vivo and are currently in clinical trials for the treatment of chronic cough, bladder incontinence, visceral pain and hypertension. Antagonists to P2X7 receptors are being investigated for the treatment of inflammatory disorders, including neurodegenerative diseases. Other investigations are in progress for the use of purinergic agents for the treatment of osteoporosis, myocardial infarction, irritable bowel syndrome, epilepsy, atherosclerosis, depression, autism, diabetes, and cancer.

  12. Notch Signaling Components

    PubMed Central

    Liu, Zhi-Yan; Wu, Tao; Li, Qing; Wang, Min-Cong; Jing, Li; Ruan, Zhi-Ping; Yao, Yu; Nan, Ke-Jun; Guo, Hui

    2016-01-01

    Abstract Non-small-cell lung cancer (NSCLC) is a lethal and aggressive malignancy. Currently, the identities of prognostic and predictive makers of NSCLC have not been fully established. Dysregulated Notch signaling has been implicated in many human malignancies, including NSCLC. However, the prognostic value of measuring Notch signaling and the utility of developing Notch-targeted therapies in NSCLC remain inconclusive. The present study investigated the association of individual Notch receptor and ligand levels with lung adenocarcinoma (ADC) and squamous cell carcinoma (SCC) prognosis using the Kaplan-Meier plotte database. This online database encompasses 2437 lung cancer samples. Hazard ratios with 95% confidence intervals were calculated. The results showed that higher Notch1, Notch2, JAG1, and DLL1 mRNA expression predicted better overall survival (OS) in lung ADC, but showed no significance in SCC patients. Elevated Notch3, JAG2, and DLL3 mRNA expression was associated with poor OS of ADC patients, but not in SCC patients. There was no association between Notch4 and OS in either lung ADC or SCC patients. In conclusion, the set of Notch1, Notch2, JAG1, DLL1 and that of Notch3, JAG2, DLL3 played opposing prognostic roles in lung ADC patients. Neither set of Notch receptors and ligands was indicative of lung SCC prognosis. Notch signaling could serve as promising marker to predict outcomes in lung ADC patients. The distinct features of lung cancer subtypes and Notch components should be considered when developing future Notch-targeted therapies. PMID:27196489

  13. Biphonation in voice signals

    NASA Astrophysics Data System (ADS)

    Herzel, Hanspeter; Reuter, Robert

    1996-06-01

    Irregularities in voiced speech are often observed as a consequence of vocal fold lesions, paralyses, and other pathological conditions. Many of these instabilities are related to the intrinsic nonlinearities in the vibrations of the vocal folds. In this paper, a specific nonlinear phenomenon is discussed: The appearance of two independent fundamental frequencies termed biphonation. Several narrow-band spectrograms are presented showing biphonation in signals from voice patients, a newborn cry, a singer, and excised larynx experiments. Finally, possible physiological mechanisms of instabilities of the voice source are discussed.

  14. Optical signal computing

    NASA Astrophysics Data System (ADS)

    Cathey, Wade Thomas; Schmidt, Rodney A.; Moddel, Garret

    1989-12-01

    Architectures for optical symbolic computing were designed, devices were designed and built that were specifically for the architectures, and test circuits for some of the logic elements were designed, constructed, and operated. The research elements were designed, constructed, and operated. The research led to novel architectures for optical symbolic computing. Devices were developed that are suitable for optical 2-D memory and logic. These devices are pixilated photo-addressed spatial light modulators (SLMs) with a three terminal arrangement so that the threshold can be adjusted. Spinoff non-pixilated devices are useful as high frame rate, high resolution SLMs that can be used for many optical signal processing applications.

  15. Arabidopsis brassinosteroid signaling pathway.

    PubMed

    Belkhadir, Youssef; Wang, Xuelu; Chory, Joanne

    2006-12-05

    Plants control their size through the action of several phytohormones. One class of growth-promoting hormones is the brassinosteroids (BRs), the polyhydroxylated steroid hormones of plants. Here, we present the Arabidopsis-specific proteins that are the founding members of key BR signaling pathway components found in all plants. The genetic studies that identified these components are unique to Arabidopsis owing to its rapid generation time, sophisticated genetics, and facile transformation protocols, thereby highlighting the importance of a reference plant for understanding fundamental processes in all land plants.

  16. Biphonation in voice signals

    SciTech Connect

    Herzel, H.; Reuter, R.

    1996-06-01

    Irregularities in voiced speech are often observed as a consequence of vocal fold lesions, paralyses, and other pathological conditions. Many of these instabilities are related to the intrinsic nonlinearities in the vibrations of the vocal folds. In this paper, a specific nonlinear phenomenon is discussed: The appearance of two independent fundamental frequencies termed biphonation. Several narrow-band spectrograms are presented showing biphonation in signals from voice patients, a newborn cry, a singer, and excised larynx experiments. Finally, possible physiological mechanisms of instabilities of the voice source are discussed. {copyright} {ital 1996 American Institute of Physics.}

  17. Signal Processing Circuit Development.

    DTIC Science & Technology

    1986-07-01

    Simplified active filter circuit 64 42. Video output amplifier 66 43. 64/128 gated clock circuitry 68 44. Two pole Sallen-Key active filters 7!1 45. Switched...four quadrant multiplier, log compression, multiple pole active video filtering and black level control. In what follows in this report an attempt...chip is shown in Fiqu-e 5. This is the master synch chip which generates all of the control signals necessary for TV monitor presentation of video data

  18. Calcium Signaling in the Liver

    PubMed Central

    Amaya, Maria Jimena; Nathanson, Michael H.

    2014-01-01

    Intracellular free Ca2+ ([Ca2+]i) is a highly versatile second messenger that regulates a wide range of functions in every type of cell and tissue. To achieve this versatility, the Ca2+ signaling system operates in a variety of ways to regulate cellular processes that function over a wide dynamic range. This is particularly well exemplified for Ca2+ signals in the liver, which modulate diverse and specialized functions such as bile secretion, glucose metabolism, cell proliferation, and apoptosis. These Ca2+ signals are organized to control distinct cellular processes through tight spatial and temporal coordination of [Ca2+]i signals, both within and between cells. This article will review the machinery responsible for the formation of Ca2+ signals in the liver, the types of subcellular, cellular, and intercellular signals that occur, the physiological role of Ca2+ signaling in the liver, and the role of Ca2+ signaling in liver disease. PMID:23720295

  19. A controllable water signal transistor.

    PubMed

    Wu, Lili; Zhou, Xiaoyan; Lu, Hangjun; Liang, Qing; Kou, Jianlong; Wu, Fengmin; Fan, Jintu

    2017-03-27

    We performed molecular dynamics simulations to study the regulating ability of water chains confined in a Y-shaped nanochannel. It was shown that a signal at the molecular level could be controlled by two other charge-induced signals when the water chains were confined in a Y-shaped nanochannel, demonstrating promising applications as water signal transistors in nanosignal systems. The mechanism of a water signal transistor is similar to a signal logic device. This remarkable ability to control the water signal is attributed to the strong dipole-ordering of the water chains in the nanochannel. The controllable water signal process of the Y-shaped nanochannel provides opportunities for future application in the design of molecular-scale signal devices.

  20. Signal quality of endovascular electroencephalography

    NASA Astrophysics Data System (ADS)

    He, Bryan D.; Ebrahimi, Mosalam; Palafox, Leon; Srinivasan, Lakshminarayan

    2016-02-01

    Objective, Approach. A growing number of prototypes for diagnosing and treating neurological and psychiatric diseases are predicated on access to high-quality brain signals, which typically requires surgically opening the skull. Where endovascular navigation previously transformed the treatment of cerebral vascular malformations, we now show that it can provide access to brain signals with substantially higher signal quality than scalp recordings. Main results. While endovascular signals were known to be larger in amplitude than scalp signals, our analysis in rabbits borrows a standard technique from communication theory to show endovascular signals also have up to 100× better signal-to-noise ratio. Significance. With a viable minimally-invasive path to high-quality brain signals, patients with brain diseases could one day receive potent electroceuticals through the bloodstream, in the course of a brief outpatient procedure.

  1. Simple hormones but complex signalling.

    PubMed

    Vogler, Hannes; Kuhlemeier, Cris

    2003-02-01

    It has not been easy to make sense of the pleiotropic effects of plant hormones, especially of auxins; but now, it has become possible to study these effects within the framework of what we know about signal transduction in general. Changes in local auxin concentrations, perhaps even actively maintained auxin gradients, signal to networks of transcription factors, which in turn signal to downstream effectors. Transcription factors can also signal back to hormone biosynthetic pathways.

  2. Macula densa cell signaling.

    PubMed

    Bell, P Darwin; Lapointe, Jean Yves; Peti-Peterdi, János

    2003-01-01

    Macula densa cells are renal sensor elements that detect changes in distal tubular fluid composition and transmit signals to the glomerular vascular elements. This tubuloglomerular feedback mechanism plays an important role in regulating glomerular filtration rate and blood flow. Macula densa cells detect changes in luminal sodium chloride concentration through a complex series of ion transport-related intracellular events. NaCl entry via a Na:K:2Cl cotransporter and Cl exit through a basolateral channel lead to cell depolarization and increases in cytosolic calcium. Na/H exchange (NHE2) results in cell alkalization, whereas intracellular [Na] is regulated by an apically located H(Na)-K ATPase and not by the traditional basolateral Na:K ATPase. Communication from macula densa cells to the glomerular vascular elements involves ATP release across the macula densa basolateral membrane through a maxi-anion channel. The adaptation of multi-photon microscopy is providing new insights into macula densa-glomerular signaling.

  3. Calcium signalling in diabetes.

    PubMed

    Guerrero-Hernandez, Agustin; Verkhratsky, Alexei

    2014-11-01

    Molecular cascades responsible for Ca(2+) homeostasis and Ca(2+) signalling could be assembled in highly plastic toolkits that define physiological adaptation of cells to the environment and which are intimately involved in all types of cellular pathology. Control over Ca(2+) concentration in different cellular compartments is intimately linked to cell metabolism, because (i) ATP production requires low Ca(2+), (ii) Ca(2+) homeostatic systems consume ATP and (iii) Ca(2+) signals in mitochondria stimulate ATP synthesis being an essential part of excitation-metabolic coupling. The communication between the ER and mitochondria plays an important role in this metabolic fine tuning. In the insulin resistance state and diabetes this communication has been impaired leading to different disorders, for instance, diminished insulin production by pancreatic β cells, reduced heart and skeletal muscle contractility, reduced NO production by endothelial cells, increased glucose production by liver, increased lipolysis by adipose cells, reduced immune responses, reduced cognitive functions, among others. All these processes eventually trigger degenerative events resulting in overt diabetes due to reduction of pancreatic β cell mass, and different complications of diabetes, such as retinopathy, nephropathy, neuropathy, and different cardiovascular diseases.

  4. GTPases in semaphorin signaling.

    PubMed

    Püschel, Andreas W

    2007-01-01

    A hallmark of semaphorin receptors is their interaction with multiple GTPases. Plexins, the signal transducing component of semaphorin receptors, directly associate with several GTPases. In addition, they not only recruit guaninine nucleotide exchange factors (GEFs) and GTPase activating proteins (GAPs) but also are the only known integral membrane proteins that show a catalytic activity as GAPs for small GTPases. GTPases function upstream of semaphorin receptors and regulate the activity of plexins through an interaction with the cytoplasmic domain. The association of Plexin-Al (Sema3A receptor) or Plexin-B1 (Sema4D receptor) with the GTPase Rnd1 and ligand-dependent receptor clustering are required for their activity as R-Ras GAPs. The GTPases R-Ras and Rho function downstream of plexins and are required for the repulsive effects of semaphorins. In this review, I will focus on the role of GTPases in signaling by two plexins that have been analyzed in most detail, Plexin-A1 and Plexin-B1.

  5. Calcium Signaling and Neurodegeneration

    PubMed Central

    2010-01-01

    Neurodegenerative disorders, such as Alzheimer’s disease (AD), Parkinson’s disease (PD), amyotrophic lateral sclerosis (ALS), Huntington’s disease (HD), and spinocerebellar ataxias (SCA) are very important both for fundamental science and for practical medicine. Despite extensive research into the causes of these diseases, clinical researchers have had very limited progress and, as of now, there is still no cure for any of these diseases. One of the main obstacles in the way of creating treatments for these disorders is the fact that their etiology and pathophysiology still remain unclear. This paper reviews results that support the so–called “calcium hypothesis of neurodegenerative diseases.” The calcium hypothesis states that the atrophic and degenerative processes in the neurons of AD, PD, ALS, HD, and SCA patients are accompanied by alterations in calcium homeostasis. Moreover, the calcium hypothesis states that this deregulation of calcium signaling is one of the early–stage and key processes in the pathogenesis of these diseases. Based on the results we reviewed, we conclude that the calcium channels and other proteins involved in the neuronal calcium signaling system are potential drug targets for AD, PD, ALS, HD, and SCA therapy. PMID:22649630

  6. Endocannabinoid Signaling in Autism.

    PubMed

    Chakrabarti, Bhismadev; Persico, Antonio; Battista, Natalia; Maccarrone, Mauro

    2015-10-01

    Autism spectrum disorder (ASD) is a complex behavioral condition with onset during early childhood and a lifelong course in the vast majority of cases. To date, no behavioral, genetic, brain imaging, or electrophysiological test can specifically validate a clinical diagnosis of ASD. However, these medical procedures are often implemented in order to screen for syndromic forms of the disorder (i.e., autism comorbid with known medical conditions). In the last 25 years a good deal of information has been accumulated on the main components of the "endocannabinoid (eCB) system", a rather complex ensemble of lipid signals ("endocannabinoids"), their target receptors, purported transporters, and metabolic enzymes. It has been clearly documented that eCB signaling plays a key role in many human health and disease conditions of the central nervous system, thus opening the avenue to the therapeutic exploitation of eCB-oriented drugs for the treatment of psychiatric, neurodegenerative, and neuroinflammatory disorders. Here we present a modern view of the eCB system, and alterations of its main components in human patients and animal models relevant to ASD. This review will thus provide a critical perspective necessary to explore the potential exploitation of distinct elements of eCB system as targets of innovative therapeutics against ASD.

  7. Universal signal conditioning amplifier

    NASA Technical Reports Server (NTRS)

    Medelius, Pedro J.; Hallberg, Carl; Cecil, Jim

    1994-01-01

    A state-of-the-art instrumentation amplifier capable of being used with most types of transducers has been developed at the Kennedy Space Center. This Universal Signal Conditioning Amplifier (USCA) can eliminate costly measurement setup item and troubleshooting, improve system reliability and provide more accurate data than conventional amplifiers. The USCA can configure itself for maximum resolution and accuracy based on information read from a RAM chip attached to each transducer. Excitation voltages or current are also automatically configured. The amplifier uses both analog and digital state-of-the-art technology with analog-to-digital conversion performed in the early stages in order to minimize errors introduced by offset and gain drifts in the analog components. A dynamic temperature compensation scheme has been designed to achieve and maintain 12-bit accuracy of the amplifier from 0 to 70 C. The digital signal processing section allows the implementation of digital filters up to 511th order. The amplifier can also perform real-time linearizations up to fourth order while processing data at a rate of 23.438 kS/s. Both digital and analog outputs are available from the amplifier.

  8. The Akt signaling pathway

    PubMed Central

    Madhunapantula, SubbaRao V; Mosca, Paul J

    2011-01-01

    Studies using cultured melanoma cells and patient tumor biopsies have demonstrated deregulated PI3 kinase-Akt3 pathway activity in ∼70% of melanomas. Furthermore, targeting Akt3 and downstream PRAS40 has been shown to inhibit melanoma tumor development in mice. Although these preclinical studies and several other reports using small interfering RNAs and pharmacological agents targeting key members of this pathway have been shown to retard melanoma development, analysis of early Phase I and Phase II clinical trials using pharmacological agents to target this pathway demonstrate the need for (1) selection of patients whose tumors have PI3 kinase-Akt pathway deregulation, (2) further optimization of therapeutic agents for increased potency and reduced toxicity, (3) the identification of additional targets in the same pathway or in other signaling cascades that synergistically inhibit the growth and progression of melanoma, and (4) better methods for targeted delivery of pharmaceutical agents inhibiting this pathway. In this review we discuss key potential targets in PI3K-Akt3 signaling, the status of pharmacological agents targeting these proteins, drugs under clinical development, and strategies to improve the efficacy of therapeutic agents targeting this pathway. PMID:22157148

  9. Neural Network Communications Signal Processing

    DTIC Science & Technology

    1994-08-01

    This final technical report describes the research and development- results of the Neural Network Communications Signal Processing (NNCSP) Program...The objectives of the NNCSP program are to: (1) develop and implement a neural network and communications signal processing simulation system for the...purpose of exploring the applicability of neural network technology to communications signal processing; (2) demonstrate several configurations of the

  10. SIG. Signal Processing, Analysis, & Display

    SciTech Connect

    Hernandez, J.; Lager, D.; Azevedo, S.

    1992-01-22

    SIG is a general-purpose signal processing, analysis, and display program. Its main purpose is to perform manipulations on time and frequency-domain signals. However, it has been designed to ultimately accommodate other representations for data such as multiplexed signals and complex matrices. Two user interfaces are provided in SIG; a menu mode for the unfamiliar user and a command mode for more experienced users. In both modes errors are detected as early as possible and are indicated by friendly, meaningful messages. An on-line HELP package is also included. A variety of operations can be performed on time and frequency-domain signals including operations on the samples of a signal, operations on the entire signal, and operations on two or more signals. Signal processing operations that can be performed are digital filtering (median, Bessel, Butterworth, and Chebychev), ensemble average, resample, auto and cross spectral density, transfer function and impulse response, trend removal, convolution, Fourier transform and inverse window functions (Hamming, Kaiser-Bessel), simulation (ramp, sine, pulsetrain, random), and read/write signals. User definable signal processing algorithms are also featured. SIG has many options including multiple commands per line, command files with arguments, commenting lines, defining commands, and automatic execution for each item in a `repeat` sequence. Graphical operations on signals and spectra include: x-y plots of time signals; real, imaginary, magnitude, and phase plots of spectra; scaling of spectra for continuous or discrete domain; cursor zoom; families of curves; and multiple viewports.

  11. SIG. Signal Processing, Analysis, & Display

    SciTech Connect

    Hernandez, J.; Lager, D.; Azevedo, S.

    1992-01-22

    SIG is a general-purpose signal processing, analysis, and display program. Its main purpose is to perform manipulations on time-and frequency-domain signals. However, it has been designed to ultimately accommodate other representations for data such as multiplexed signals and complex matrices. Two user interfaces are provided in SIG - a menu mode for the unfamiliar user and a command mode for more experienced users. In both modes errors are detected as early as possible and are indicated by friendly, meaningful messages. An on-line HELP package is also included. A variety of operations can be performed on time and frequency-domain signals including operations on the samples of a signal, operations on the entire signal, and operations on two or more signals. Signal processing operations that can be performed are digital filtering (median, Bessel, Butterworth, and Chebychev), ensemble average, resample, auto and cross spectral density, transfer function and impulse response, trend removal, convolution, Fourier transform and inverse window functions (Hamming, Kaiser-Bessel), simulation (ramp, sine, pulsetrain, random), and read/write signals. User definable signal processing algorithms are also featured. SIG has many options including multiple commands per line, command files with arguments, commenting lines, defining commands, and automatic execution for each item in a repeat sequence. Graphical operations on signals and spectra include: x-y plots of time signals; real, imaginary, magnitude, and phase plots of spectra; scaling of spectra for continuous or discrete domain; cursor zoom; families of curves; and multiple viewports.

  12. SIG. Signal Processing, Analysis, & Display

    SciTech Connect

    Hernandez, J.; Lager, D.; Azevedo, S.

    1992-01-22

    SIG is a general-purpose signal processing, analysis, and display program. Its main purpose is to perform manipulations on time- and frequency-domain signals. However, it has been designed to ultimately accommodate other representations for data such as multiplexed signals and complex matrices. Two user interfaces are provided in SIG - a menu mode for the unfamiliar user and a command mode for more experienced users. In both modes errors are detected as early as possible and are indicated by friendly, meaningful messages. An on-line HELP package is also included. A variety of operations can be performed on time- and frequency-domain signals including operations on the samples of a signal, operations on the entire signal, and operations on two or more signals. Signal processing operations that can be performed are digital filtering (median, Bessel, Butterworth, and Chebychev), ensemble average, resample, auto and cross spectral density, transfer function and impulse response, trend removal, convolution, Fourier transform and inverse window functions (Hamming, Kaiser-Bessel), simulation (ramp, sine, pulsetrain, random), and read/write signals. User definable signal processing algorithms are also featured. SIG has many options including multiple commands per line, command files with arguments,commenting lines, defining commands, and automatic execution for each item in a repeat sequence. Graphical operations on signals and spectra include: x-y plots of time signals; real, imaginary, magnitude, and phase plots of spectra; scaling of spectra for continuous or discrete domain; cursor zoom; families of curves; and multiple viewports.

  13. Salicylic acid signaling inhibits apoplastic reactive oxygen species signaling

    PubMed Central

    2014-01-01

    Background Reactive oxygen species (ROS) are used by plants as signaling molecules during stress and development. Given the amount of possible challenges a plant face from their environment, plants need to activate and prioritize between potentially conflicting defense signaling pathways. Until recently, most studies on signal interactions have focused on phytohormone interaction, such as the antagonistic relationship between salicylic acid (SA)-jasmonic acid and cytokinin-auxin. Results In this study, we report an antagonistic interaction between SA signaling and apoplastic ROS signaling. Treatment with ozone (O3) leads to a ROS burst in the apoplast and induces extensive changes in gene expression and elevation of defense hormones. However, Arabidopsis thaliana dnd1 (defense no death1) exhibited an attenuated response to O3. In addition, the dnd1 mutant displayed constitutive expression of defense genes and spontaneous cell death. To determine the exact process which blocks the apoplastic ROS signaling, double and triple mutants involved in various signaling pathway were generated in dnd1 background. Simultaneous elimination of SA-dependent and SA-independent signaling components from dnd1 restored its responsiveness to O3. Conversely, pre-treatment of plants with SA or using mutants that constitutively activate SA signaling led to an attenuation of changes in gene expression elicited by O3. Conclusions Based upon these findings, we conclude that plants are able to prioritize the response between ROS and SA via an antagonistic action of SA and SA signaling on apoplastic ROS signaling. PMID:24898702

  14. Signal localization: a new approach in signal discovery.

    PubMed

    Malov, Sergey V; Antonik, Alexey; Tang, Minzhong; Berred, Alexandre; Zeng, Yi; O'Brien, Stephen J

    2017-01-01

    A new approach for statistical association signal identification is developed in this paper. We consider a strategy for nonprecise signal identification by extending the well-known signal detection and signal identification methods applicable to the multiple testing problem. Collection of statistical instruments under the presented approach is much broader than under the traditional signal identification methods, allowing more efficient signal discovery. Further assessments of maximal value and average statistics in signal discovery are improved. While our method does not attempt to detect individual predictors, it instead detects sets of predictors that are jointly associated with the outcome. Therefore, an important application would be in genome wide association study (GWAS), where it can be used to detect genes which influence the phenotype but do not contain any individually significant single nucleotide polymorphism (SNP). We compare power of the signal identification method based on extremes of single p-values with the signal localization method based on average statistics for logarithms of p-values. A simulation analysis informs the application of signal localization using the average statistics for wide signals discovery in Gaussian white noise process. We apply average statistics and the localization method to GWAS to discover better gene influences of regulating loci in a Chinese cohort developed for risk of nasopharyngeal carcinoma (NPC). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Rise-Time Distortion of Signal without Carrying Signal

    NASA Astrophysics Data System (ADS)

    Bukhman, N. S.

    2016-08-01

    The article deals with one-dimensional problem of rise-time distortion signal without carrying signal, that appears in the starting point intermittently, that is signal distortion at front edge or one of its derivative. The authors show that front edge of signal isn't distorted in case of propagation in unrestricted (including absorbing) area (amplitude of starting signal step or of one of its derivatives doesn't change) and move with the accuracy of vacuum light speed. The paper proves that it is the time interval shortage that causes signal loss with the route extension, but not the reduction of its starting amplitude, during which front edge of signal retains its starting value. The research presents new values for this time interval.

  16. Binary-Signal Recovery

    NASA Technical Reports Server (NTRS)

    Griebeler, Elmer L.

    2011-01-01

    Binary communication through long cables, opto-isolators, isolating transformers, or repeaters can become distorted in characteristic ways. The usual solution is to slow the communication rate, change to a different method, or improve the communication media. It would help if the characteristic distortions could be accommodated at the receiving end to ease the communication problem. The distortions come from loss of the high-frequency content, which adds slopes to the transitions from ones to zeroes and zeroes to ones. This weakens the definition of the ones and zeroes in the time domain. The other major distortion is the reduction of low frequency, which causes the voltage that defines the ones or zeroes to drift out of recognizable range. This development describes a method for recovering a binary data stream from a signal that has been subjected to a loss of both higher-frequency content and low-frequency content that is essential to define the difference between ones and zeroes. The method makes use of the frequency structure of the waveform created by the data stream, and then enhances the characteristics related to the data to reconstruct the binary switching pattern. A major issue is simplicity. The approach taken here is to take the first derivative of the signal and then feed it to a hysteresis switch. This is equivalent in practice to using a non-resonant band pass filter feeding a Schmitt trigger. Obviously, the derivative signal needs to be offset to halfway between the thresholds of the hysteresis switch, and amplified so that the derivatives reliably exceed the thresholds. A transition from a zero to a one is the most substantial, fastest plus movement of voltage, and therefore will create the largest plus first derivative pulse. Since the quiet state of the derivative is sitting between the hysteresis thresholds, the plus pulse exceeds the plus threshold, switching the hysteresis switch plus, which re-establishes the data zero to one transition

  17. Notch Signaling in Pancreatic Development

    PubMed Central

    Li, Xu-Yan; Zhai, Wen-Jun; Teng, Chun-Bo

    2015-01-01

    The Notch signaling pathway plays a significant role in embryonic cell fate determination and adult tissue homeostasis. Various studies have demonstrated the deep involvement of Notch signaling in the development of the pancreas and the lateral inhibition of Notch signaling in pancreatic progenitor differentiation and maintenance. The targeted inactivation of the Notch pathway components promotes premature differentiation of the endocrine pancreas. However, there is still the contrary opinion that Notch signaling specifies the endocrine lineage. Here, we review the current knowledge of the Notch signaling pathway in pancreatic development and its crosstalk with the Wingless and INT-1 (Wnt) and fibroblast growth factor (FGF) pathways. PMID:26729103

  18. Chaos-Based Signal Processing

    NASA Astrophysics Data System (ADS)

    Ogorzałek, Maciej J.

    2002-07-01

    Nonlinear systems exhibiting chaotic behavior can be considered as a source of a great variety of signals. Given a time series measured from a known or an unknown dynamical system we address a series of problems, such as section-wise approximation of the measured signal by pieces of trajectories from a chosen nonlinear dynamical system (model) signal restoration when the measured signal has been corrupted e.g. by quantization; signal coding and compression. The key to attack these problems is estimation of the initial conditions for a dynamical system which is used as the generator of approximating waveforms.

  19. Quantitative measures for redox signaling.

    PubMed

    Pillay, Ché S; Eagling, Beatrice D; Driscoll, Scott R E; Rohwer, Johann M

    2016-07-01

    Redox signaling is now recognized as an important regulatory mechanism for a number of cellular processes including the antioxidant response, phosphokinase signal transduction and redox metabolism. While there has been considerable progress in identifying the cellular machinery involved in redox signaling, quantitative measures of redox signals have been lacking, limiting efforts aimed at understanding and comparing redox signaling under normoxic and pathogenic conditions. Here we have outlined some of the accepted principles for redox signaling, including the description of hydrogen peroxide as a signaling molecule and the role of kinetics in conferring specificity to these signaling events. Based on these principles, we then develop a working definition for redox signaling and review a number of quantitative methods that have been employed to describe signaling in other systems. Using computational modeling and published data, we show how time- and concentration- dependent analyses, in particular, could be used to quantitatively describe redox signaling and therefore provide important insights into the functional organization of redox networks. Finally, we consider some of the key challenges with implementing these methods. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Epigenetic signaling in schizophrenia

    PubMed Central

    Ibi, Daisuke; González-Maeso, Javier

    2015-01-01

    Histone modifications and DNA methylation represent central dynamic and reversible processes that regulate gene expression and contribute to cellular phenotypes. These epigenetic marks have been shown to play fundamental roles in a diverse set of signaling and behavioral outcomes. Psychiatric disorders such as schizophrenia and depression are complex and heterogeneous diseases with multiple and independent factors that may contribute to their pathophysiology, making challenging to find a link between specific elements and the underlying mechanisms responsible for the disorder and its treatment. Growing evidences suggest that epigenetic modifications in certain brain regions and neural circuits represent a key mechanism through which environmental factors interact with individual’s genetic constitution to affect risk of psychiatric conditions throughout life. This review focuses on recent advances that directly implicate epigenetic modifications in schizophrenia and antipsychotic drug action. PMID:26120009

  1. Collider Signal I :. Resonance

    NASA Astrophysics Data System (ADS)

    Tait, Tim M. P.

    2010-08-01

    These TASI lectures were part of the summer school in 2008 and cover the collider signal associated with resonances in models of physics beyond the Standard Model. I begin with a review of the Z boson, one of the best-studied resonances in particle physics, and review how the Breit-Wigner form of the propagator emerges in perturbation theory and discuss the narrow width approximation. I review how the LEP and SLAC experiments could use the kinematics of Z events to learn about fermion couplings to the Z. I then make a brief survey of models of physics beyond the Standard Model which predict resonances, and discuss some of the LHC observables which we can use to discover and identify the nature of the BSM physics. I finish up with a discussion of the linear moose that one can use for an effective theory description of a massive color octet vector particle.

  2. Chemotherapy and signaling

    PubMed Central

    Bagnyukova, Tetyana; Serebriiskii, Ilya G; Zhou, Yan; Hopper-Borge, Elizabeth A; Golemis, Erica A

    2010-01-01

    In recent years, oncologists have begun to conclude that chemotherapy has reached a plateau of efficacy as a primary treatment modality, even if toxicity can be effectively controlled. Emerging specific inhibitors of signaling and metabolic pathways (i.e., targeted agents) contrast with traditional chemotherapy drugs in that the latter primarily interfere with the DNA biosynthesis and the cell replication machinery. In an attempt to improve on the efficacy, combination of targeted drugs with conventional chemotherapeutics has become a routine way of testing multiple new agents in early phase clinical trials. This review discusses the recent advances including integrative systematic biology and RNAi approaches to counteract the chemotherapy resistance and to buttress the selectivity, efficacy and personalization of anticancer drug therapy. PMID:20935499

  3. Oxygen sensing and signaling.

    PubMed

    van Dongen, Joost T; Licausi, Francesco

    2015-01-01

    Oxygen is an indispensable substrate for many biochemical reactions in plants, including energy metabolism (respiration). Despite its importance, plants lack an active transport mechanism to distribute oxygen to all cells. Therefore, steep oxygen gradients occur within most plant tissues, which can be exacerbated by environmental perturbations that further reduce oxygen availability. Plants possess various responses to cope with spatial and temporal variations in oxygen availability, many of which involve metabolic adaptations to deal with energy crises induced by low oxygen. Responses are induced gradually when oxygen concentrations decrease and are rapidly reversed upon reoxygenation. A direct effect of the oxygen level can be observed in the stability, and thus activity, of various transcription factors that control the expression of hypoxia-induced genes. Additional signaling pathways are activated by the impact of oxygen deficiency on mitochondrial and chloroplast functioning. Here, we describe the molecular components of the oxygen-sensing pathway.

  4. Signaling dynamics and peroxisomes.

    PubMed

    Mast, Fred D; Rachubinski, Richard A; Aitchison, John D

    2015-08-01

    Peroxisomes are remarkably responsive organelles. Their composition, abundance and even their mechanism of biogenesis are influenced strongly by cell type and the environment. This plasticity underlies peroxisomal functions in metabolism and the detoxification of dangerous reactive oxygen species. However, peroxisomes are integrated into the cellular system as a whole such that they communicate intimately with other organelles, control signaling dynamics as in the case of innate immune responses to infectious disease, and contribute to processes as fundamental as longevity. The increasing evidence for peroxisomes having roles in various cellular and organismal functions, combined with their malleability, suggests complex mechanisms operate to control cellular dynamics and the specificity of cellular responses and functions extending well beyond the peroxisome itself. A deeper understanding of the functions of peroxisomes and the mechanisms that control their plasticity could offer opportunities for exploiting changes in peroxisome abundance to control cellular function. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. [Signal Processing Suite Design

    NASA Technical Reports Server (NTRS)

    Sahr, John D.; Mir, Hasan; Morabito, Andrew; Grossman, Matthew

    2003-01-01

    Our role in this project was to participate in the design of the signal processing suite to analyze plasma density measurements on board a small constellation (3 or 4) satellites in Low Earth Orbit. As we are new to space craft experiments, one of the challenges was to simply gain understanding of the quantity of data which would flow from the satellites, and possibly to interact with the design teams in generating optimal sampling patterns. For example, as the fleet of satellites were intended to fly through the same volume of space (displaced slightly in time and space), the bulk plasma structure should be common among the spacecraft. Therefore, an optimal, limited bandwidth data downlink would take advantage of this commonality. Also, motivated by techniques in ionospheric radar, we hoped to investigate the possibility of employing aperiodic sampling in order to gain access to a wider spatial spectrum without suffering aliasing in k-space.

  6. Cannabinoid signaling system

    PubMed Central

    Gómez, María; Hernández, Mariluz

    2008-01-01

    The cannabinoid signaling system is located during brain development in a position concordant with playing a modulatory function in the regulation of neuronal and glial cell proliferation and migration, survival of neural progenitors, axonal elongation and synaptogenesis and differentiation of oligodendrocytes and formation of myelin. This assumption is based on the fact that CB1 receptors and their ligands emerge early in brain development and are transiently expressed in certain brain regions that play key roles in these processes. We have recently proposed that this modulatory action might be exerted through regulating L1 and other cell adhesion molecules, that are also key elements for those processes. The present commentary will address these two questions trying to summarize all the available evidence and to suggest the future directions for research. PMID:19262157

  7. [Signal Processing Suite Design

    NASA Technical Reports Server (NTRS)

    Sahr, John D.; Mir, Hasan; Morabito, Andrew; Grossman, Matthew

    2003-01-01

    Our role in this project was to participate in the design of the signal processing suite to analyze plasma density measurements on board a small constellation (3 or 4) satellites in Low Earth Orbit. As we are new to space craft experiments, one of the challenges was to simply gain understanding of the quantity of data which would flow from the satellites, and possibly to interact with the design teams in generating optimal sampling patterns. For example, as the fleet of satellites were intended to fly through the same volume of space (displaced slightly in time and space), the bulk plasma structure should be common among the spacecraft. Therefore, an optimal, limited bandwidth data downlink would take advantage of this commonality. Also, motivated by techniques in ionospheric radar, we hoped to investigate the possibility of employing aperiodic sampling in order to gain access to a wider spatial spectrum without suffering aliasing in k-space.

  8. Signal conditioning system

    NASA Technical Reports Server (NTRS)

    Zahzah, Mohamad (Inventor); Korkosz, Gregory J. (Inventor); Bohr, Gerald (Inventor)

    2000-01-01

    A current-driven signal conditioning system comprising a first terminal, a second terminal, a strain gauge, and an instrumentation amplifier is disclosed. The strain gauge is adapted to measure a deformation of a structure and to generate a resistance which corresponds to the measured deformation. The instrumentation amplifier is adapted to be connected between the first terminal and the second terminal. The instrumentation amplifier is further adapted to be connected to the strain gauge and to place an output current on the second terminal. The output current is proportional to the resistance generated by the strain gauge. An output resister is coupled between the strain gauge and the second terminal, and a capacitor is coupled between the resister and the first terminal. A zenor diode is coupled between the first terminal and the strain gauge, and a diode is also coupled between the first terminal and the strain gauge.

  9. Adipogenesis and WNT signalling

    PubMed Central

    Christodoulides, Constantinos; Lagathu, Claire; Sethi, Jaswinder K.; Vidal-Puig, Antonio

    2015-01-01

    An inability of adipose tissue to expand consequent to exhausted capacity to recruit new adipocytes might underlie the association between obesity and insulin resistance. Adipocytes arise from mesenchymal precursors whose commitment and differentiation along the adipocytic lineage is tightly regulated. These regulatory factors mediate cross-talk between adipose cells, ensuring that adipocyte growth and differentiation are coupled to energy storage demands. The WNT family of autocrine and paracrine growth factors regulates adult tissue maintenance and remodelling and, consequently, is well suited to mediate adipose cell communication. Indeed, several recent reports, summarized in this review, implicate WNT signalling in regulating adipogenesis. Manipulating the WNT pathway to alter adipose cellular makeup, therefore, constitutes an attractive drug-development target to combat obesity-associated metabolic complications. PMID:19008118

  10. Surface electromyogram signal modelling.

    PubMed

    McGill, K C

    2004-07-01

    The paper reviews the fundamental components of stochastic and motor-unit-based models of the surface electromyogram (SEMG). Stochastic models used in ergonomics and kinesiology consider the SEMG to be a stochastic process whose amplitude is related to the level of muscle activation and whose power spectral density reflects muscle conduction velocity. Motor-unit-based models for describing the spatio-temporal distribution of individual motor-unit action potentials throughout the limb are quite robust, making it possible to extract precise information about motor-unit architecture from SEMG signals recorded by multi-electrode arrays. Motor-unit-based models have not yet been proven as successful, however, for extracting information about recruitment and firing rates throughout the full range of contraction. The relationship between SEMG and force during natural dynamic movements is much too complex to model in terms of single motor units.

  11. Interactive digital signal processor

    NASA Technical Reports Server (NTRS)

    Mish, W. H.; Wenger, R. M.; Behannon, K. W.; Byrnes, J. B.

    1982-01-01

    The Interactive Digital Signal Processor (IDSP) is examined. It consists of a set of time series analysis Operators each of which operates on an input file to produce an output file. The operators can be executed in any order that makes sense and recursively, if desired. The operators are the various algorithms used in digital time series analysis work. User written operators can be easily interfaced to the sysatem. The system can be operated both interactively and in batch mode. In IDSP a file can consist of up to n (currently n=8) simultaneous time series. IDSP currently includes over thirty standard operators that range from Fourier transform operations, design and application of digital filters, eigenvalue analysis, to operators that provide graphical output, allow batch operation, editing and display information.

  12. Biasing GPCR signaling from inside.

    PubMed

    Shukla, Arun K

    2014-01-28

    The discovery of "functional selectivity" or "biased signaling" through G protein-coupled receptors (GPCRs) has redefined the classical GPCR signaling paradigm. Moreover, the therapeutic potential of biased signaling by and biased ligands for GPCRs is changing the landscape of GPCR drug discovery. The concept of biased signaling has primarily been developed and discussed in the context of ligands that bind to the extracellular regions of GPCRs. However, two recent reports demonstrate that it is also possible to bias GPCR signaling from inside the cell by targeting intracellular regions of these receptors. These findings present a novel handle for delineating the functional outcomes of biased signaling by GPCRs. Moreover, these approaches also uncover a previously unexplored framework for biasing GPCR signaling for drug discovery.

  13. Signaling on the endocytic pathway.

    PubMed

    McPherson, P S; Kay, B K; Hussain, N K

    2001-06-01

    Ligand binding to receptor tyrosine kinases and G-protein-coupled receptors initiates signal transduction events and induces receptor endocytosis via clathrin-coated pits and vesicles. While receptor-mediated endocytosis has been traditionally considered an effective mechanism to attenuate ligand-activated responses, more recent studies demonstrate that signaling continues on the endocytic pathway. In fact, certain signaling events, such as the activation of the extracellular signal-regulated kinases, appear to require endocytosis. Protein components of signal transduction cascades can assemble at clathrin coated pits and remain associated with endocytic vesicles following their dynamin-dependent release from the plasma membrane. Thus, endocytic vesicles can function as a signaling compartment distinct from the plasma membrane. These observations demonstrate that endocytosis plays an important role in the activation and propagation of signaling pathways.

  14. EEG signal analysis: a survey.

    PubMed

    Subha, D Puthankattil; Joseph, Paul K; Acharya U, Rajendra; Lim, Choo Min

    2010-04-01

    The EEG (Electroencephalogram) signal indicates the electrical activity of the brain. They are highly random in nature and may contain useful information about the brain state. However, it is very difficult to get useful information from these signals directly in the time domain just by observing them. They are basically non-linear and nonstationary in nature. Hence, important features can be extracted for the diagnosis of different diseases using advanced signal processing techniques. In this paper the effect of different events on the EEG signal, and different signal processing methods used to extract the hidden information from the signal are discussed in detail. Linear, Frequency domain, time - frequency and non-linear techniques like correlation dimension (CD), largest Lyapunov exponent (LLE), Hurst exponent (H), different entropies, fractal dimension(FD), Higher Order Spectra (HOS), phase space plots and recurrence plots are discussed in detail using a typical normal EEG signal.

  15. Systemic signaling during plant defense.

    PubMed

    Kachroo, Aardra; Robin, Guillaume P

    2013-08-01

    Systemic acquired resistance (SAR) is a type of pathogen-induced broad-spectrum resistance in plants. During SAR, primary infection-induced rapid generation and transportation of mobile signal(s) 'prepare' the rest of the plant for subsequent infections. Several, seemingly unrelated, mobile chemical inducers of SAR have been identified, at least two of which function in a feed-back regulatory loop with a lipid transfer-like protein. Signal(s) perception in the systemic tissues relies on the presence of an intact cuticle, the waxy layer covering all aerial parts of the plant. SAR results in chromatin modifications, which prime systemic tissues for enhanced and rapid signaling derived from salicylic acid, which along with its signaling components is key for SAR induction. This review summarizes recent findings related to SAR signal generation, movement, and perception. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Oxytocin receptor signalling.

    PubMed

    Devost, Dominic; Wrzal, Paulina; Zingg, Hans H

    2008-01-01

    The great diversity of the expression sites and proposed function of the oxytocin (OXT) receptor (OXTR) is paralleled by a diversity of its signalling pathways, many of which have still remained unexplored. We have used different approaches to discover novel pathways. By means of a phosphoproteomics approach, we have detected several distinct OXT-induced changes in tyrosine as well as threonine phosphorylation states of intracellular protein in myometrial cells. The most prominent change involved dephosphorylation of a 95-kDa phosphothreonine moiety. By N-terminal amino acid microsequence analysis, this moiety was shown to correspond to eukaryotic translation factor eEF2. This protein is a key regulator of protein synthesis and mediates, upon dephosphorylation, the translocation step of peptide chain elongation. These findings define a novel mechanism by which OXT assumes a so far unrecognized trophic function. We next elucidated the intracellular pathway(s) involved. We found that this effect is not mediated by any of the known pathways known to induce eEF2 dephosphorylation (mTOR, ERK1/2 or p38) but by protein kinase C. Consistent with this idea, we also found that direct stimulation of protein kinase C with a phorbol ester induced eEF2 dephosphorylation in myometrial cells. Using phosphoERK antibodies, we discovered by Western blotting that OXT induced phosphorylation of a higher molecular weight ERK-related protein. We were able to show that this band corresponded to "big MAP kinase1" or ERK5. ERK5 is part of a distinct MAPK cascade and promotes expression of the myosin light chain gene and plays an obligatory role in muscle cell development and differentiation. The role of ERK5 in myometrium has remained unexplored, but it is likely to represent an important novel pathway mediating OXT's effects on smooth muscle function. Further elucidation of these novel signalling pathways will have significant relevance for the development of novel pathway-specific OXTR

  17. Ultra-wideband ranging precision and accuracy

    NASA Astrophysics Data System (ADS)

    MacGougan, Glenn; O'Keefe, Kyle; Klukas, Richard

    2009-09-01

    This paper provides an overview of ultra-wideband (UWB) in the context of ranging applications and assesses the precision and accuracy of UWB ranging from both a theoretical perspective and a practical perspective using real data. The paper begins with a brief history of UWB technology and the most current definition of what constitutes an UWB signal. The potential precision of UWB ranging is assessed using Cramer-Rao lower bound analysis. UWB ranging methods are described and potential error sources are discussed. Two types of commercially available UWB ranging radios are introduced which are used in testing. Actual ranging accuracy is assessed from line-of-sight testing under benign signal conditions by comparison to high-accuracy electronic distance measurements and to ranges derived from GPS real-time kinematic positioning. Range measurements obtained in outdoor testing with line-of-sight obstructions and strong reflection sources are compared to ranges derived from classically surveyed positions. The paper concludes with a discussion of the potential applications for UWB ranging.

  18. Integrin endosomal signalling suppresses anoikis

    PubMed Central

    Alanko, Jonna; Mai, Anja; Jacquemet, Guillaume; Schauer, Kristine; Kaukonen, Riina; Saari, Markku; Goud, Bruno; Ivaska, Johanna

    2016-01-01

    Integrin containing focal adhesions (FAs) transmit extracellular signals across the plasma membrane to modulate cell adhesion, signalling and survival. Although integrins are known to undergo continuous endo/exocytic traffic, potential impact of endocytic traffic on integrin-induced signals is unknown. Here, we demonstrate that integrin signalling is not restricted to cell-ECM adhesions and identify an endosomal signalling platform that supports integrin signalling away from the plasma membrane. We show that active focal adhesion kinase (FAK), an established marker of integrin-ECM downstream signalling, localises with active integrins on endosomes. Integrin endocytosis positively regulates adhesion-induced FAK activation, which is early endosome antigen-1 (EEA1) and small GTPase Rab21 dependent. FAK binds directly to purified endosomes and becomes activated on them, suggesting a role for endocytosis in enhancing distinct integrin downstream signalling events. Finally, endosomal integrin signalling contributes to cancer-related processes such as anoikis resistance, anchorage-independence and metastasis. Integrins are heterodimeric cell surface adhesion receptors functioning as integrators of the extra-cellular matrix (ECM) driven cues, the cellular cytoskeleton and the cellular signalling apparatus 1.Upon adhesion, integrins trigger the formation of plasma-membrane proximal large mechanosensing and signal-transmitting protein clusters depicted as “adhesomes” 2, 3. In addition, integrins undergo constant endocytic traffic to facilitate focal adhesion turnover, cell migration, invasion and cytokinesis 4. For other receptor systems it is well established that endocytic membrane traffic regulates bioavailability of cell-surface molecules and therefore the intensity and/or specificity of receptor-initiated signals 5, 6. Although active integrins and their ligands have been detected in endosomes 7–9 and increased integrin recycling to the plasma membrane contributes

  19. Crosstalk between Photoreceptor and Sugar Signaling Modulates Floral Signal Transduction

    PubMed Central

    Matsoukas, Ianis G.

    2017-01-01

    Over the past decade, integrated genetic, cellular, proteomic and genomic approaches have begun to unravel the surprisingly crosstalk between photoreceptors and sugar signaling in regulation of floral signal transduction. Although a number of physiological factors in the pathway have been identified, the molecular genetic interactions of some components are less well understood. The further elucidation of the crosstalk mechanisms between photoreceptors and sugar signaling will certainly contribute to our better understanding of the developmental circuitry that controls floral signal transduction. This article summarizes our current knowledge of this crosstalk, which has not received much attention, and suggests possible directions for future research. PMID:28659814

  20. Crosstalk between Photoreceptor and Sugar Signaling Modulates Floral Signal Transduction.

    PubMed

    Matsoukas, Ianis G

    2017-01-01

    Over the past decade, integrated genetic, cellular, proteomic and genomic approaches have begun to unravel the surprisingly crosstalk between photoreceptors and sugar signaling in regulation of floral signal transduction. Although a number of physiological factors in the pathway have been identified, the molecular genetic interactions of some components are less well understood. The further elucidation of the crosstalk mechanisms between photoreceptors and sugar signaling will certainly contribute to our better understanding of the developmental circuitry that controls floral signal transduction. This article summarizes our current knowledge of this crosstalk, which has not received much attention, and suggests possible directions for future research.