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IEEE 6th International Conference on Photonics (ICP)

作者： Horiguchi, Tsuneo Shibaura Inst Technol Koto Ku 3-7-5 Toyosu Tokyo 1358548 Japan

ISBN: (纸本)9781467381536

We review coding techniques for fiber-optic distributed strain and temperature sensors, Brillouin Optical Time Domain Analysis (BOTDA) and Brillouin Optical Time Domain Reflectometry (BOTDR), based on stimulated and spontaneous Brillouin scatterings. The straightforward employment of previous coding techniques fails to enhance signal-to-noise ratio with high spatial resolution. The failure is caused by acousticwave damping effects which involve in the Brillouin scatterings. We show that both the advantageous use and the reduction of the acoustic damping effects lead to successful and efficient implementation of coding techniques to high spatial resolution fiber-optic Brillouin sensors.

关键词： BOTDA BOTDR Brillouin scattering distributed fiber sensor pulse coding

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Design of a fast echo matching algorithm to reduce crosstalk with Doppler shifts in ultrasonic ranging

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MEASUREMENT SCIENCE AND TECHNOLOGY 2017年第2期28卷 025103-025103页

作者： Liu, Lei Guo, Rui Wu, Jun-an Nanjing Univ Sci & Technol Sch Mech Engn Nanjing 210094 Jiangsu Peoples R China Eindhoven Univ Technol Dept Mech Engn NL-5600 MB Eindhoven Netherlands Nanjing Univ Sci & Technol ZNDY Minist Key Lab Nanjing 210094 Jiangsu Peoples R China

Crosstalk is a main factor for wrong distance measurement by ultrasonic sensors, and this problem becomes more difficult to deal with under Doppler effects. In this paper, crosstalk reduction with Doppler shifts on small platforms is focused on, and a fast echo matching algorithm (FEMA) is proposed on the basis of chaotic sequences and pulse coding technology, then verified through applying it to match practical echoes. Finally, we introduce how to select both better mapping methods for chaotic sequences, and algorithm parameters for higher achievable maximum of cross-correlation peaks. The results indicate the following: logistic mapping is preferred to generate good chaotic sequences, with high autocorrelation even when the length is very limited;FEMA can not only match echoes and calculate distance accurately with an error degree mostly below 5%, but also generates nearly the same calculation cost level for static or kinematic ranging, much lower than that by direct Doppler compensation (DDC) with the same frequency compensation step;The sensitivity to threshold value selection and performance of FEMA depend significantly on the achievable maximum of cross-correlation peaks, and a higher peak is preferred, which can be considered as a criterion for algorithm parameter optimization under practical conditions.

关键词： crosstalk Doppler shifts ultrasonic sensor chaotic sequences pulse coding echo matching

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Elimination of second-harmonics in CMUTs using square pulse excitation

Elimination of second-harmonics in CMUTs using square pulse ...

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IEEE International Ultrasonics Symposium

作者： Anders Lei Soren Elmin Diederichsen Sebastian Molbech Hansen Matthias Bo Stuart Jan Peter Bagge Jorgen Arendt Jensen Erik Vilain Thomsen Department of Micro and Nanotechnology Technical University of Denmark DK-2800 Kgs. Lyngby Denmark Center for Fast Ultrasound Imaging Department of Electrical Engineering Technical University of Denmark DK-2800 Kgs. Lyngby Denmark BK Ultrasound Herlev Denmark

ISBN: (纸本)9781467398985

The harmonic imaging mode is today a fundamental part of ultrasound imaging;it is not only used for suppressing the grating lobe artifact, but also to reduce many other acoustical artifacts in the ultrasound image. A vital performance parameter for accepting CMUT probes as a clinical usable transducer technology is, that it can support harmonic imaging. The large bandwidth of the CMUT is a clear advantage for harmonic imaging, but the inherent nonlinear behavior of the CMUT poses an issue as it is difficult to dissociate the harmonics generated in the tissue from the harmonic content of the transmitted signal. This work presents how proper pulse coding of a bipolar pulser, which is present in most commercial ultrasound scanners, can reduce the intrinsic generated harmonic to fundamental pressure amplitude ratio to below -35 dB, making CMUT probes usable for clinical applications.

关键词： Harmonic analysis Imaging Sonar equipment Ultrasonic imaging Voltage measurement Acoustics Acoustic measurements Ultrasonography Acoustic measurements voltage measurement Acoustics Fourier analysis harmonics Imaging Sonar equipment pulse coding SQUARE WAVE pulse impulse excitation characteristic parameter Harmonic Content

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OBSERVATIONS OF FIELD-ALIGNED IRREGULARITIES IN THE IONOSPHERE USING MULTI-FREQUENCY RANGE IMAGING TECHNIQUE

OBSERVATIONS OF FIELD-ALIGNED IRREGULARITIES IN THE IONOSPHE...

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IEEE International Geoscience and Remote Sensing Symposium (IGARSS)

作者： Chen, Jenn-Shyong Chu, Yen-Hsyang Su, Ching-Lun Hashiguchi, Hiroyuki Li, Ying China Med Univ Ctr Gen Educ Shenyang 110001 Peoples R China Natl Cent Univ Inst Space Sci Taoyuan Taiwan Kyoto Univ Res Inst Sustainable Humanosphere Kyoto 6068501 Japan Yuan Ze Univ Dept Commun Engn Taoyuan Taiwan

ISBN: (纸本)9781479979295

Multi-frequency range imaging (RIM) implemented in the Middle and Upper atmosphere Radar (MUR;34.85 degrees N, 136.10 degrees E) was utilized for the first time to observe the field-aligned irregularities (FAI) in the mid-latitude ionosphere. Five frequencies equally spaced between 46 MHz and 47 MHz were employed. Two types of RIM data collected with 16-element binary complementary codes and without phase codes were examined, respectively. It is shown that RIM works well and can resolve striation structures of FAI within the pulse length, thereby improving the range resolution of measurement greatly. However, duplicated echoes due to code-sidelobes appeared frequently at altitudes above and below the source regions. A procedure taking advantage of RIM to mitigate the code-sidelobe echoes is progressing.

关键词： range imaging field-aligned irregularities ionosphere pulse coding

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OBSERVATIONS OF FIELD-ALIGNED IRREGULARITIES IN THE IONOSPHERE USING MULTI-FREQUENCY RANGE IMAGING TECHNIQUE

OBSERVATIONS OF FIELD-ALIGNED IRREGULARITIES IN THE IONOSPHE...

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IEEE International Geoscience and Remote Sensing Symposium

作者： Jenn-Shyong Chen Yen-Hsyang Chu Ching-Lun Su Hiroyuki Hashiguchi Ying Li Center for General Education China Medical University Institute of Space Science National Central University Research Institute for Sustainable Humanosphere Kyoto University Department of Communications Engineering Yuan Ze University

ISBN: (纸本)9781479979301

Multi-frequency range imaging (RIM) implemented in the Middle and Upper atmosphere Radar (MUR;34.85°N, 136.10°E) was utilized for the first time to observe the field-aligned irregularities (FAI) in the mid-latitude ionosphere. Five frequencies equally spaced between 46 MHz and 47 MHz were employed. Two types of RIM data collected with 16-element binary complementary codes and without phase codes were examined, respectively. It is shown that RIM works well and can resolve striation structures of FAI within the pulse length, thereby improving the range resolution of measurement greatly. However, duplicated echoes due to code-sidelobes appeared frequently at altitudes above and below the source regions. A procedure taking advantage of RIM to mitigate the code-sidelobe echoes is progressing.

关键词： Range imaging Field-aligned irregularities Ionosphere pulse coding

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COMPARISON OF SINGLE- AND DOUBLE-SIDED pulse WIDTH MODULATED SIGNALS WITH NON-LINEAR PREDISTORTION

COMPARISON OF SINGLE- AND DOUBLE-SIDED PULSE WIDTH MODULATED...

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5th European DSP Education and Research Conference (EDERC)

作者： Morrison, Christopher Weiss, Stephan Macleod, Malcolm D. Stewart, Robert W. Inst Syst Level Integrat Edinburgh Midlothian Scotland

ISBN: (纸本)9781467345972;9781467345958

Class D amplifiers are based on a low-bit pulse width modulated (PWM) signal reconstructed through the lowpass characteristic of the loudspeaker. To create a PWM signal, a non-linear conversion from a standard pulse code modulated (PCM) signal has to be performed. The non-linear distortion created in this conversion process can be minimised by non-linear predistortion based on a Wiener-Hammerstein system. In this paper, we compare single and double-sided PWM conversion, whereby the former exhibits a higher resolution but also higher non-linearity compared to the latter. The trade-off between both approaches in creating a highly linear high performance class D audio amplifier is demonstrated by means of simulations and an implementation.

关键词： pulse width modulation signals Predistortion pulse WIDTH pulse coding class D audio amplifier CONVERSION PROCESS High definition Pokeweed Mitogens pulse width modulation Nonlinear distortion

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Comparison of single- and double-sided pulse width modulated signals with non-linear predistortion

Comparison of single- and double-sided pulse width modulated...

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European DSP Education and Research Conference (EDERC)

作者： Christopher Morrison Stephan Weiss Malcolm D. Macleod Robert W. Stewart Institute for System Level Integration Edinburgh UK Dept of EEE University of Strathclyde Glasgow UK QinetiQ Limited UK

ISBN: (纸本)9781467345965

关键词： simulations andan implementation pulse width modulation signals simulating pulse coding class D audio amplifier signals High definition CONVERSION PROCESS Pokeweed Mitogens pulse width modulation Nonlinear distortion pulse WIDTH

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Experimental results of a 10-element, Gatling-styled Marx generator system

Experimental results of a 10-element, Gatling-styled Marx ge...

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IEEE International Power Modulator and High Voltage Conference

作者： Mayes, J.R. Carey, W.J. Applied Physical Electronics L.C Austin TX United States ARC Technology Whitewater AR United States

ISBN: (纸本)9781424471294

A Gatling Marx generator system has been previously presented[1]. This effort focused on the summation of high voltage pulses, delivered by multiple unique Marx generators, by a common adder element. More recent efforts have focused on understanding the system's functionality and uniqueness. This paper discusses the experimental results of a ten-element Gatling system, with discussions and demonstrations illustrating the functionality of the Gatling system. Topics include demonstrating the ability to achieve extreme repetition rates in a burst mode, pulse coding techniques and wave shape synthesis. The Marx generators, for this effort, were supported by a common trigger source and a common charge voltage source configured for discrete voltage pickoffs. Theoretical considerations are made and supported by experimental results. © 2010 IEEE.

关键词： Marx generators Voltage pulses Summation pulse coding Repetition rate measurement result waveforms charging voltage

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Response of a Chaotic Spiking Neuron to Various Periodic Inputs and Its Potential Applications

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IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES 2009年第8期E92A卷 2053-2060页

作者： Torikai, Hiroyuki Nishigamit, Toru Osaka Univ Grad Sch Engn Sci Toyonaka Osaka 5608531 Japan

In this paper a chaotic spiking neuron is presented and its response characteristics to various periodic inputs are analyzed. A return map which can analytically describe the dynamics of the neuron is derived. Using the map, it is theoretically shown that a set of neurons can encode various periodic inputs into a set of spike-trains in such a way that a spike density of a summation of the spike-trains can approximate the waveform of the input. Based on the theoretical results, some potential applications of the presented neuron are also discussed. Using a prototype circuit, typical encoding functions of the neuron are confirmed by experimental measurements.

关键词： forced oscillator chaos spiking neuron pulse coding

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An artificial chaotic spiking neuron inspired by spiral ganglion cell: Paralleled spike encoding, theoretical analysis, and electronic circuit implementation

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NEURAL NETWORKS 2009年第5-6期22卷 664-673页

作者： Torikai, Hiroyuki Nishigami, Toru Osaka Univ Grad Sch Engn Sci Osaka 5608531 Japan

A novel chaotic spiking neuron is presented and its nonlinear dynamics and encoding functions are analyzed. A set of paralleled N neurons accepts a common analog input and outputs a set of N chaotic spike-trains. Three theorems which guarantee that the neurons can encode the analog input into a Summation of the N chaotic spike-trains are derived: (1) a spike histogram of the summed spike-train can mimic waveforms Of Various inputs, (2) the spike-trains do not synchronize to each other and thus the summed spike-train can have N times higher encoding resolution than each single spike-train, and (3) firing rates of the neurons can be adjusted by internal parameters. The theorems are proven by using nonlinear iterative maps and are confirmed by numerical simulations as well. Electronic circuit implementation methods of the paralleled neurons are also presented and typical paralleled encoding functions are confirmed by both experimental measurements and SPICE simulations. (C) 2009 Elsevier Ltd. All rights reserved.

关键词： Spiking neuron Chaos pulse coding Spiral ganglion cell

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