The disguised covert detection method that imitates whale calls has received great attention in recent years because it can solve the traditional problem of the trade-off between long-range detection and covert detect...The disguised covert detection method that imitates whale calls has received great attention in recent years because it can solve the traditional problem of the trade-off between long-range detection and covert detection.However,under strong reverberation conditions,traditional echo signal processing methods based on matched filtering will be greatly disturbed.Based on this,a disguised sonar signal waveform design is proposed based on imitating whale calls and computationally efficient anti-reverberation echo signal processing method.Firstly,this article proposed a disguised sonar signal waveform design method based on imitating whale calls.This method uses linear frequency modulation(LFM)signals to replace LFM-like segments in real whale calls,and extracts the envelope of the real whale call’s LFM-like segment to modify the LFM signal.Secondly,this article proposed an echo signal processing method of fractional Fourier transform(FrFT)based on target echo locating of synchronization signals.This method uses the synchronization signal to locate the target echo,and determines the step-size interval of the FrFT based on the information carried by the synchronization signal.Compared with the traditional FrFT,this method effectively reduces the amount of calculation and also improves the anti-reverberation ability.Finally,the excellent performance of the proposed method is verified by simulation results.展开更多
The effect of signal modulating noise in bistable stochastic resonance systems was studied theoretically and experimentally. A mathematical analysis was made on the bistable stochastic resonance model with small syste...The effect of signal modulating noise in bistable stochastic resonance systems was studied theoretically and experimentally. A mathematical analysis was made on the bistable stochastic resonance model with small system parameters. An analogue circuit was designed to perform the effect. The effect of signal modulating noise was shown in the analog simulation experiment. The analog experiment was conducted for two sinusoidal signals with different frequencies. The results show that there are a sinusoidal component corresponding to the input sinusoidal signal and a noise component presented as a Wiener process corresponding to the input white noise in the system output. By properly selecting system parameters, the effect of signal modulating noise can be manifested in the system output.展开更多
基金National Natural Science Foundations of China under Grant(Nos.61971307,61905175,51775377)National Key Research and Development Plan Project(No.2020YFB2010800)+5 种基金Fok Ying Tung Education Foundation(No.171055)China Postdoctoral Science Foundation(No.2020M680878)Guangdong Province Key Research and Development Plan Project(No.2020B0404030001)Tianjin Science and Technology Plan Project(No.20YDTPJC01660)Foreign Affairs Committee of China Aviation Development Sichuan Gas Turbine Research Institute(Nos.GJCZ-2020-0040,GJCZ-2020-0041)Science and Technology on Underwater Information and Control Laboratory under Grant(No.6142218081811)。
文摘The disguised covert detection method that imitates whale calls has received great attention in recent years because it can solve the traditional problem of the trade-off between long-range detection and covert detection.However,under strong reverberation conditions,traditional echo signal processing methods based on matched filtering will be greatly disturbed.Based on this,a disguised sonar signal waveform design is proposed based on imitating whale calls and computationally efficient anti-reverberation echo signal processing method.Firstly,this article proposed a disguised sonar signal waveform design method based on imitating whale calls.This method uses linear frequency modulation(LFM)signals to replace LFM-like segments in real whale calls,and extracts the envelope of the real whale call’s LFM-like segment to modify the LFM signal.Secondly,this article proposed an echo signal processing method of fractional Fourier transform(FrFT)based on target echo locating of synchronization signals.This method uses the synchronization signal to locate the target echo,and determines the step-size interval of the FrFT based on the information carried by the synchronization signal.Compared with the traditional FrFT,this method effectively reduces the amount of calculation and also improves the anti-reverberation ability.Finally,the excellent performance of the proposed method is verified by simulation results.
基金Project (10276032) supportedjointly by the National Natural Science Foundation of China and by the Science Foundationof China Academy of Engineering Physics NSAFproject(2005038228) supported by Postdoctoral Science Foundation of China projectsupported by the Postdoctoral Science Foundation of Central South University(2005)
文摘The effect of signal modulating noise in bistable stochastic resonance systems was studied theoretically and experimentally. A mathematical analysis was made on the bistable stochastic resonance model with small system parameters. An analogue circuit was designed to perform the effect. The effect of signal modulating noise was shown in the analog simulation experiment. The analog experiment was conducted for two sinusoidal signals with different frequencies. The results show that there are a sinusoidal component corresponding to the input sinusoidal signal and a noise component presented as a Wiener process corresponding to the input white noise in the system output. By properly selecting system parameters, the effect of signal modulating noise can be manifested in the system output.
