The advantages of using phase-coded pulse compression technique for radio fuze systems are evaluated. With building mathematical models a matched filter has been implemented successfully. Various simulations for pulse...The advantages of using phase-coded pulse compression technique for radio fuze systems are evaluated. With building mathematical models a matched filter has been implemented successfully. Various simulations for pulse compression waveform coding were done to evaluate the performance of fuze system under noisy environment. The results of the simulation and the data analysis show that the phase-coded pulse compression gets a good result in the signal identification of the radio fuze with matched filter. Simultaneously, a suitable sidelobe suppression filter is established by simulation, the suppressed sidelobe level is acceptable to radio fuze application.展开更多
Single pulse excited ultrasonic guided wave surfers high attenuation during the propagation in long bones.This results in small amplitude and low signal-to-noise ratio（SNR）of measured signals.Thus,the Barker code ex...Single pulse excited ultrasonic guided wave surfers high attenuation during the propagation in long bones.This results in small amplitude and low signal-to-noise ratio（SNR）of measured signals.Thus,the Barker code excitation is introduced into long bone detection to improve the quality of received signals,due to its efficiency in increasing amplitude and SNR.Both simulation and in vitro experiment were performed,and the results were decoded by the weighted match filter（WMF） and the finite impulse response- least squares inverse filter（FIRLSIF）,respectively.The comparison between the results of Barker code excitation and sine pulse excitation was presented.For 13-bit Barker code excitation,WMF produced 13 times larger amplitude than sine pulse excitation,while FIR-LSIF achieved higher peak-sidelobe-level（PSL） of -63.59 dB and better performance in noise suppression.The results show that the Barker code excited guided waves have the potential to be applied to the long bone detection.展开更多
A simple and convcnient method to gain bulk acoustic wave Barker code sequence is presented and the results of the correlation are givcn. The transducer response to a unit electric pulse is used as a unit code constit...A simple and convcnient method to gain bulk acoustic wave Barker code sequence is presented and the results of the correlation are givcn. The transducer response to a unit electric pulse is used as a unit code constituting the Barker code sequence of acoustic signal. The phase precision of the code sequence as well as the fairly ideal response function are guaranteed by the high accuraey of a DATA-2020 Arbitrary Waveform Synthesizer and a DATA-6000 Universal Wavcform Analyzer. Some deviations between the experiments and thcory are caused by the transient response and timc delay characteristics of the ultrasonic tansducer.展开更多
文摘The advantages of using phase-coded pulse compression technique for radio fuze systems are evaluated. With building mathematical models a matched filter has been implemented successfully. Various simulations for pulse compression waveform coding were done to evaluate the performance of fuze system under noisy environment. The results of the simulation and the data analysis show that the phase-coded pulse compression gets a good result in the signal identification of the radio fuze with matched filter. Simultaneously, a suitable sidelobe suppression filter is established by simulation, the suppressed sidelobe level is acceptable to radio fuze application.
基金supported by the NSFC(11174060,11327405)the Science and Technology Support Program of Shanghai(13441901900)the Ph.D.Programs Foundation of the Ministry of Education of China(20110071130004,20130071110020)
文摘Single pulse excited ultrasonic guided wave surfers high attenuation during the propagation in long bones.This results in small amplitude and low signal-to-noise ratio（SNR）of measured signals.Thus,the Barker code excitation is introduced into long bone detection to improve the quality of received signals,due to its efficiency in increasing amplitude and SNR.Both simulation and in vitro experiment were performed,and the results were decoded by the weighted match filter（WMF） and the finite impulse response- least squares inverse filter（FIRLSIF）,respectively.The comparison between the results of Barker code excitation and sine pulse excitation was presented.For 13-bit Barker code excitation,WMF produced 13 times larger amplitude than sine pulse excitation,while FIR-LSIF achieved higher peak-sidelobe-level（PSL） of -63.59 dB and better performance in noise suppression.The results show that the Barker code excited guided waves have the potential to be applied to the long bone detection.
文摘A simple and convcnient method to gain bulk acoustic wave Barker code sequence is presented and the results of the correlation are givcn. The transducer response to a unit electric pulse is used as a unit code constituting the Barker code sequence of acoustic signal. The phase precision of the code sequence as well as the fairly ideal response function are guaranteed by the high accuraey of a DATA-2020 Arbitrary Waveform Synthesizer and a DATA-6000 Universal Wavcform Analyzer. Some deviations between the experiments and thcory are caused by the transient response and timc delay characteristics of the ultrasonic tansducer.
