To boost the performance of 4-ary pulse amplitude modulated(PAM) at low signal-to-noise ratio(SNR), bistable stochastic resonance(BSR) system is introduced into digital communications system and get a reliable signal ...To boost the performance of 4-ary pulse amplitude modulated(PAM) at low signal-to-noise ratio(SNR), bistable stochastic resonance(BSR) system is introduced into digital communications system and get a reliable signal detection scheme. In this paper, we first analyse BSR system for different amplitudes of 4-ary PAM signals. The steadystate of the bistable system will be statistically distinct, and the feasibility of the proposed detection scheme is confirmed. On this basis, we present a detailed study on steady-state transitions of the BSR system, and an explicit expression of the bistable system parameters is derived. By setting the bistable system parameters, bistable system, 4-ary PAM signal, and noise reach the resonance state, and the BSR-based detection scheme is implemented. Moreover, we derive an analytical expression to calculate the symbol error rate(SER) of 4-ary PAM signals with the BSR-based detection under additive white Gaussian noise(AWGN). Finally, the simulation results validate that BSR-based detection scheme can improve the detection performance while efficiently reducing the symbol error rate.展开更多
A one-dimensional self-consistent fluid numerical model was developed to study the ignition characteristics of a pulsc-tmxlulated(PM)radio-frequency(RF)glow discharge in atmospheric helium assisted by a sub-microsecon...A one-dimensional self-consistent fluid numerical model was developed to study the ignition characteristics of a pulsc-tmxlulated(PM)radio-frequency(RF)glow discharge in atmospheric helium assisted by a sub-microsecond voltage excited pulsed discharge.The temporal evolution of discharge current density and electron density during PM RF discharge burst was investigated to demonstrate the discharge ignition characteristics with or without the pulsed discharge.Under the assistance of pulsed discharge,the electron density in RF discharge burst reaches the magnitude of 1.87 x 1017-3m within 10 RF cycles,accompanied by the formation of sheath structure.It proposes that the pulsed discharge plays an important role in the ignition of PM RF discharge burst.Furthermore,the dynamics of PM RF glow discharge arc demonstrated by the spatiotcmporal evolution of the election density with and without pulsed discharge.The spatial profiles of electron density,electron energy and electric field at specific time instants arc given to explain the assistive role of the pulsed discharge on PM RF discharge ignition.展开更多
Using a one-dimensional fluid model, the pulse-modulated radio-frequency dielectric barrier discharge in atmospheric helium is described. The influences of the pulse duty cycle on the discharge characteristics are stu...Using a one-dimensional fluid model, the pulse-modulated radio-frequency dielectric barrier discharge in atmospheric helium is described. The influences of the pulse duty cycle on the discharge characteristics are studied. The numerical results show that the dependence of discharge characteristics on the duty cycle is sensitive in the region of around 40% duty cycle under the given simulation parameters. In the case of a larger duty cycle, the plasma density is higher, the discharge becomes more intense, but the power consumption is higher. When the duty cycle is lower, one can get a weaker discharge, lower plasma density and higher electron temperature in the bulk plasma. In practical applications, in order to get a higher plasma density and a lower power consumption, it is more important to choose a suitable duty cycle to modulate the RF power supply.展开更多
针对常见雷达信号识别方法不能适应小脉宽信号识别的问题,本文提出了一种基于频谱复杂度的雷达信号调制方式识别方法。该方法通过提取信号频谱复杂度特征、信号平方频谱特征、谱峰特征以及最小二乘直线拟合方差特征,以4个特征参数为出发...针对常见雷达信号识别方法不能适应小脉宽信号识别的问题,本文提出了一种基于频谱复杂度的雷达信号调制方式识别方法。该方法通过提取信号频谱复杂度特征、信号平方频谱特征、谱峰特征以及最小二乘直线拟合方差特征,以4个特征参数为出发点,设计了一个基于频谱复杂度的树形结构流程。该流程首先对雷达信号的频谱序列进行量化,计算量化后的6种雷达信号的频谱复杂度,根据信号频谱复杂度的不同进行分类,然后根据所求特征参数对6种雷达信号进行分层次识别。仿真结果表明,基于频谱复杂度的雷达信号调制方式识别方法能够实现在窄脉冲的情况下的雷达信号调制方式识别,当信噪比大于6 d B时具有比较好的识别效果。展开更多
基金supported by the National Natural Science Foundation of China (61631015, 61501354, 61501356, and 61573202)the Fundamental Research Funds of the Ministry of Education (7215433803)+5 种基金the Foundation of State Key Laboratory of Integrated Services Networks (ISN1101002)Higher School Subject Innovation Engineering Plan (B08038)Science and Technology Innovation Team Key Plan of Shaanxi Province (2016KCT-01)The Fundamental Research Funds of the Ministry of Education, China (Grant No. JB160101)The Key Laboratory Foundation of Ministry of Industry and Information Technology (KF20181912)China Postdoctoral Science Foundation (2018M631122)
文摘To boost the performance of 4-ary pulse amplitude modulated(PAM) at low signal-to-noise ratio(SNR), bistable stochastic resonance(BSR) system is introduced into digital communications system and get a reliable signal detection scheme. In this paper, we first analyse BSR system for different amplitudes of 4-ary PAM signals. The steadystate of the bistable system will be statistically distinct, and the feasibility of the proposed detection scheme is confirmed. On this basis, we present a detailed study on steady-state transitions of the BSR system, and an explicit expression of the bistable system parameters is derived. By setting the bistable system parameters, bistable system, 4-ary PAM signal, and noise reach the resonance state, and the BSR-based detection scheme is implemented. Moreover, we derive an analytical expression to calculate the symbol error rate(SER) of 4-ary PAM signals with the BSR-based detection under additive white Gaussian noise(AWGN). Finally, the simulation results validate that BSR-based detection scheme can improve the detection performance while efficiently reducing the symbol error rate.
文摘A one-dimensional self-consistent fluid numerical model was developed to study the ignition characteristics of a pulsc-tmxlulated(PM)radio-frequency(RF)glow discharge in atmospheric helium assisted by a sub-microsecond voltage excited pulsed discharge.The temporal evolution of discharge current density and electron density during PM RF discharge burst was investigated to demonstrate the discharge ignition characteristics with or without the pulsed discharge.Under the assistance of pulsed discharge,the electron density in RF discharge burst reaches the magnitude of 1.87 x 1017-3m within 10 RF cycles,accompanied by the formation of sheath structure.It proposes that the pulsed discharge plays an important role in the ignition of PM RF discharge burst.Furthermore,the dynamics of PM RF glow discharge arc demonstrated by the spatiotcmporal evolution of the election density with and without pulsed discharge.The spatial profiles of electron density,electron energy and electric field at specific time instants arc given to explain the assistive role of the pulsed discharge on PM RF discharge ignition.
基金supported jointly by National Natural Science Foundation of China （No. 10835004） and National Basic Research Program of China （No. 2010CB832901）
文摘Using a one-dimensional fluid model, the pulse-modulated radio-frequency dielectric barrier discharge in atmospheric helium is described. The influences of the pulse duty cycle on the discharge characteristics are studied. The numerical results show that the dependence of discharge characteristics on the duty cycle is sensitive in the region of around 40% duty cycle under the given simulation parameters. In the case of a larger duty cycle, the plasma density is higher, the discharge becomes more intense, but the power consumption is higher. When the duty cycle is lower, one can get a weaker discharge, lower plasma density and higher electron temperature in the bulk plasma. In practical applications, in order to get a higher plasma density and a lower power consumption, it is more important to choose a suitable duty cycle to modulate the RF power supply.
文摘针对常见雷达信号识别方法不能适应小脉宽信号识别的问题,本文提出了一种基于频谱复杂度的雷达信号调制方式识别方法。该方法通过提取信号频谱复杂度特征、信号平方频谱特征、谱峰特征以及最小二乘直线拟合方差特征,以4个特征参数为出发点,设计了一个基于频谱复杂度的树形结构流程。该流程首先对雷达信号的频谱序列进行量化,计算量化后的6种雷达信号的频谱复杂度,根据信号频谱复杂度的不同进行分类,然后根据所求特征参数对6种雷达信号进行分层次识别。仿真结果表明,基于频谱复杂度的雷达信号调制方式识别方法能够实现在窄脉冲的情况下的雷达信号调制方式识别,当信噪比大于6 d B时具有比较好的识别效果。
