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Velocity compensation methods for LPRF modulated frequency stepped-frequency(MFSF) radar 被引量:5
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作者 Guifen Xia Hongyan Su Peikang Huang 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2010年第5期746-751,共6页
In the high speed target environment,there exists serious Doppler effect in the low pulse repetition frequency(LPRF) modulated frequency stepped frequency(MFSF) radar signal.The velocity range of the target is lar... In the high speed target environment,there exists serious Doppler effect in the low pulse repetition frequency(LPRF) modulated frequency stepped frequency(MFSF) radar signal.The velocity range of the target is large and the velocity is high ambiguous,so the single method is difficult to satisfy the velocity measurement requirement.For this problem,a novel method is presented,it is a combination of cross-correlation inner frame velocity measurement and range-Doppler coupling velocity measurement.The cross-correlation inner frame method,overcoming the low Doppler tolerance of the cross-correlation between frames,can obtain the coarse velocity of the high speed target,and then the precision velocity can be obtained with the range-Doppler coupling method.The simulation results confirm the method is effective,and also it is well real-time and easy to the project application. 展开更多
关键词 modulated frequency stepped-frequency(MFSF) radar low pulse repetition frequency(LPRF) cross-correlation inner frame range-Doppler coupling.
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Discharge Characteristics of SF_6 in a Non-Uniform Electric Field Under Repetitive Nanosecond Pulses 被引量:2
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作者 冉慧娟 王磊 +2 位作者 王珏 王涛 严萍 《Plasma Science and Technology》 SCIE EI CAS CSCD 2014年第5期465-470,共6页
The characteristics of high pressure sulphur hexafluoride(SF6) discharges in a highly non-uniform electric field under repetitive nanosecond pulses are investigated in this paper.The influencing factors on discharge... The characteristics of high pressure sulphur hexafluoride(SF6) discharges in a highly non-uniform electric field under repetitive nanosecond pulses are investigated in this paper.The influencing factors on discharge process,such as gas pressure,pulse repetition frequency(PRF),and number of applied pulses,are analyzed.Experimental results show that the corona intensity weakens with the increase of gas pressure and strengthens with the increase of PRF or number of applied pulses.Spark discharge images suggest that a shorter and thicker discharge plasma channel will lead to a larger discharge current.The number of applied pulses to breakdown descends with the increase of PRF and ascends with the rise of gas pressure.The reduced electric field(E/p) decreases with the increase of PRF in all circumstances.The experimental results provide significant supplements to the dielectric characteristics of strongly electronegative gases under repetitive nanosecond pulses. 展开更多
关键词 discharge characteristic SF6 nanosecond pulse non-uniform electric field pulse repetition frequency electronegative gas
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The pulsed microwave damage trend of a bipolar transistor as a function of pulse parameters 被引量:1
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作者 马振洋 柴常春 +3 位作者 任兴荣 杨银堂 赵颖博 乔丽萍 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第2期534-538,共5页
In the present paper we conduct a theoretical study of the thermal accumulation effect of a typical bipolar transistor caused by high power pulsed microwaves(HPMs),and investigate the thermal accumulation effect as ... In the present paper we conduct a theoretical study of the thermal accumulation effect of a typical bipolar transistor caused by high power pulsed microwaves(HPMs),and investigate the thermal accumulation effect as a function of pulse repetition frequency(PRF) and duty cycle.A study of the damage mechanism of the device is carried out from the variation analysis of the distribution of the electric field and the current density.The result shows that the accumulation temperature increases with PRF increasing and the threshold for the transistor is about 2 kHz.The response of the peak temperature induced by the injected single pulses indicates that the falling time is much longer than the rising time.Adopting the fitting method,the relationship between the peak temperature and the time during the rising edge and that between the peak temperature and the time during the falling edge are obtained.Moreover,the accumulation temperature decreases with duty cycle increasing for a certain mean power. 展开更多
关键词 bipolar transistor high power microwave pulse repetition frequency duty cycle
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Generation of Atmospheric Pressure Plasma by Repetitive Nanosecond Pulses in Air Using Water Electrodes
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作者 邵涛 于洋 +3 位作者 章程 姜慧 严萍 周远翔 《Plasma Science and Technology》 SCIE EI CAS CSCD 2011年第6期735-739,共5页
Dielectric barrier discharge (DBD) excitated by pulsed power is a promising method for producing nonthermal plasma at atmospheric pressure. Discharge characteristic in a DBD with salt water as electrodes by a home-m... Dielectric barrier discharge (DBD) excitated by pulsed power is a promising method for producing nonthermal plasma at atmospheric pressure. Discharge characteristic in a DBD with salt water as electrodes by a home-made unipolar nanosecond-pulse power source is presented in this paper. The generator is capable of providing repetitive pulses with the voltage up to 30 kV and duration of 70 ns at a 300 Ω resistive load. Applied voltage and discharge current are measured under various experimental conditions. The DBD created between two liquid electrodes shows that the discharge is homogeneous and diffuse in the whole discharge regime, Spectra diagnosis is conducted by an optical emission spectroscopy. The air plasma has strong emission from nitrogen species below 400 nm, notably the nitrogen second positive system. 展开更多
关键词 non-thermal plasma dielectric barrier discharge pulsed power nanosecondpulse pulse repetition frequency atmospheric pressure air emission spectra.
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Investigation on latch-up susceptibility induced by high-power microwave in complementary metal–oxide–semiconductor inverter 被引量:4
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作者 Yu-Hang Zhang Chang-Chun Chai +4 位作者 Xin-Hai Yu Yin-Tang Yang Yang Liu Qing-Yang Fan Chun-Lei Shi 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第2期492-498,共7页
The latch-up effect induced by high-power microwave(HPM) in complementary metal–oxide–semiconductor(CMOS) inverter is investigated in simulation and theory in this paper. The physical mechanisms of excess carrie... The latch-up effect induced by high-power microwave(HPM) in complementary metal–oxide–semiconductor(CMOS) inverter is investigated in simulation and theory in this paper. The physical mechanisms of excess carrier injection and HPM-induced latch-up are proposed. Analysis on upset characteristic under pulsed wave reveals increasing susceptibility under shorter-width pulsed wave which satisfies experimental data, and the dependence of upset threshold on pulse repetitive frequency(PRF) is believed to be due to the accumulation of excess carriers. Moreover, the trend that HPMinduced latch-up is more likely to happen in shallow-well device is proposed.Finally, the process of self-recovery which is ever-reported in experiment with its correlation with supply voltage and power level is elaborated, and the conclusions are consistent with reported experimental results. 展开更多
关键词 high-power microwave latch-up repetitive pulse frequency supply voltage dependence
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The influence of pulsed parameters on the damage of a Darlington transistor 被引量:1
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作者 Qiankun Wang Changchun Chai +1 位作者 Yuqian Liu Yintang Yang 《Journal of Semiconductors》 EI CAS CSCD 2018年第9期38-43,共6页
Theoretical research on the heat accumulation effect of a Darlington transistor induced by high power microwave is conducted,and temperature variation as functions of pulse repetitive frequency(PRF)and duty cycle(D... Theoretical research on the heat accumulation effect of a Darlington transistor induced by high power microwave is conducted,and temperature variation as functions of pulse repetitive frequency(PRF)and duty cycle(DC)are studied.According to the distribution of the electronic field and the current density in the Darlington transistor,the research of the damage mechanism is carried out.The results show that for repetitive pulses with the same pulse widths and different PRFs,the value of temperature variation increases with PRF increases,and the peak temperature has almost no change when PRF is lower than 200 k Hz;while for the repetitive pulses with the same PRF and different pulse widths,the larger the pulse width is,the greater temperature variation varies.The response of the peak temperature caused by a single pulse demonstrates that there is no temperature variation when the rising time is much shorter than the falling time.In addition,the relationship between the temperature variation and the time during the rising edge time as well as that between the temperature variation and the time during the falling edge time are obtained utilizing the curve fitting method.Finally,for a certain average power,with DC increases the value of temperature variation decreases. 展开更多
关键词 Darlington transistor high power microwave pulse repetitive frequency duty cycle
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A novel RHT-TBD approach for weak targets in HPRF radar 被引量:6
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作者 Hongbo YU Guohong WANG +1 位作者 Wei WU Shuncheng TAN 《Science China Earth Sciences》 SCIE EI CAS CSCD 2016年第12期59-72,共14页
A novel approach, which can handle ambiguous data from weak targets, is proposed within the randomized Hough transform track-before-detect(RHT-TBD) framework. The main idea is that, without the pre-detection and ambig... A novel approach, which can handle ambiguous data from weak targets, is proposed within the randomized Hough transform track-before-detect(RHT-TBD) framework. The main idea is that, without the pre-detection and ambiguity resolution step at each time step, the ambiguous measurements are mapped by the multiple hypothesis ranging(MHR) procedure. In this way, all the information, based on the relativity in time and pulse repetition frequency(PRF) domains, can be gathered among different PRFs and integrated over time via a batch procedure. The final step is to perform the RHT with all the extended measurements, and the ambiguous data is unfolded while the detection decision is confirmed at the end of the processing chain.Unlike classic methods, the new approach resolves the problem of range ambiguity and detects the true track for targets. Finally, its application is illustrated to analyze and compare the performance between the proposed approach and the existing approach. Simulation results exhibit the effectiveness of this approach. 展开更多
关键词 high pulse repetition frequency weak targets TRACK-BEFORE-DETECT randomized Hough transform multiple hypothesis ranging range ambiguity resolution
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Multiple model particle flter track-before-detect for range ambiguous radar 被引量:16
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作者 Wang Guohong Tan Shuncheng +2 位作者 Guan Chengbin Wang Na Liu Zhaolei 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2013年第6期1477-1487,共11页
The middle pulse repetition frequency(MPRF)and high pulse repetition frequency(HPRF)modes are widely adopted in airborne pulse Doppler(PD)radar systems,which results in the problem that the range measurement of ... The middle pulse repetition frequency(MPRF)and high pulse repetition frequency(HPRF)modes are widely adopted in airborne pulse Doppler(PD)radar systems,which results in the problem that the range measurement of targets is ambiguous.The existing data processing based range ambiguity resolving methods work well on the condition that the signal-to-noise ratio(SNR)is high enough.In this paper,a multiple model particle flter(MMPF)based track-beforedetect(TBD)method is proposed to address the problem of target detection and tracking with range ambiguous radar in low-SNR environment.By introducing a discrete variable that denotes whether a target is present or not and the discrete pulse interval number(PIN)as components of the target state vector,and modeling the incremental variable of the PIN as a three-state Markov chain,the proposed algorithm converts the problem of range ambiguity resolving into a hybrid state fltering problem.At last,the hybrid fltering problem is implemented by a MMPF-based TBD method in the Bayesian framework.Simulation results demonstrate that the proposed Bayesian approach can estimate target state as well as the PIN simultaneously,and succeeds in detecting and tracking weak targets with the range ambiguous radar.Simulation results also show that the performance of the proposed method is superior to that of the multiple hypothesis(MH)method in low-SNR environment. 展开更多
关键词 Bayesian framework Particle flter pulse repetition frequency Range ambiguity Signal-to-noise ratio Track-before-detect
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Fast approximate maximum likelihood period estimation from incomplete timing data 被引量:2
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作者 Ye Haohuan Liu Zheng Jiang Wenli 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2013年第2期435-441,共7页
To estimate the period of a periodic point process from noisy and incomplete observations, the classical periodogram algorithm is modified. The original periodogram algorithm yields an estimate by performing grid sear... To estimate the period of a periodic point process from noisy and incomplete observations, the classical periodogram algorithm is modified. The original periodogram algorithm yields an estimate by performing grid search of the peak of a spectrum, which is equivalent to the periodogram of the periodic point process, thus its performance is found to be sensitive to the chosen grid spacing. This paper derives a novel grid spacing formula, after finding a lower bound of the width of the spectral mainlobe. By employing this formula, the proposed new estimator can determine an appropriate grid spacing adaptively, and is able to yield approximate maximum likelihood estimate (MLE) with a computational complexity of O(n2). Experimental results prove that the proposed estimator can achieve better trade-off between statistical accuracy and complexity, as compared to existing methods. Simulations also show that the derived grid spacing formula is also applicable to other estimators that operate similarly by grid search. 展开更多
关键词 Grid search Maximum likelihood period estimation Periodic point process PERIODOGRAM pulse repetition frequency
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Development of single-resonant optical parametric oscillator with tunable output from 410 nm to 630 nm
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作者 Miao Wang Jian Ma +3 位作者 Tingting Lu Shanjiang Hu Xiaolei Zhu Weibiao Chen 《Chinese Optics Letters》 SCIE EI CAS CSCD 2022年第2期80-84,共5页
A single-resonant low-threshold type-Iβ-Ba_(2)BO_(4)(BBO) optical parametric oscillator (OPO) with tunable output from 410 nm to 630 nm at 5 k Hz repetition rate is reported.By taking the noncollinear phase matching ... A single-resonant low-threshold type-Iβ-Ba_(2)BO_(4)(BBO) optical parametric oscillator (OPO) with tunable output from 410 nm to 630 nm at 5 k Hz repetition rate is reported.By taking the noncollinear phase matching method,low-threshold OPO operation could be obtained compared with the configuration of collinear phase matching,and the maximum optical–optical conversion efficiency of 11.8%was achieved at 500 nm wavelength when 0.4 m J pump pulse energy was applied.When the noncollinearity angle was preset at 1.6°,4.8°,and 6.3°,a continuously tuning output with a total spectral range of 220 nm was successfully obtained by adjusting the phase matching angle of the BBO crystal. 展开更多
关键词 optical parametric oscillator noncollinear phase matching low threshold high pulse repetition frequency widely tunable spectrum range
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