离散时间系统中的噪声辅助信号传输

摘要

基于一种平均信噪比讨论了离散时间系统中的三种典型噪声辅助信号传输的问题.仿真得到:当输入周期信号在阈下时,噪声能辅助信号的传输,随机谐振现象存在.存在一个噪声强度范围,其间系统的输出平均信噪比大于其输人平均信噪比,即输出输入平均信噪比增益大于1.随机谐振的功效随着系统阈值的增加,或噪声概率密度函数的拖尾变厚、零均值周边脉7中变窄而降低.这些结果同样说明了离散时间系统中随机谐振的复杂性,它的存在和功效也依赖于系统性能的测度和噪声类型.这些结果拓广了随机谐振在数字信号处理中的应用.%This paper discusses noise-assisted signal transmission in discrete-time systems based on an average signal-to-noise ratio (ASNR) for three representative noises. We find, by numerical simulation, when the periodic input is subthreshold, noise can assist signal transmission,stochastic resonance (SR) exists.There is a range of the noise intensity, where the output ASNR is greater than the input ANSR,I.e.,the output-input ASNR gain is greater than one.The efficacy of SR decreases as the system threshold increases, or as the impulsion of the noise probability density function (PDF) around zero mean becomes thinner and the tail in PDF becomes heavier.These results show also the complexity of SR in a discrete-time system,the existence and the efficacy of SR depends on the system measure and noise, too.These results extend further SR to be applied in digital signal processing.