基于自相关的LMS自适应滤波器期望响应构建

Construction ofdesired response of LMS adaptive filter based on autocorrelation

针对低信噪比条件下,谱减法和频谱法构建最小均方(Least Mean Square,LMS)自适应滤波器期望响应误差大的问题,在分析LMS自适应滤波原理的基础上,提出用自相关法构建LMS自适应滤波器期望响应。首先,根据噪声在不同时刻互不相关的特点,对输入信号进行采样延迟;然后,为了从低信噪比环境中检测出周期信号,对延迟后信号求自相关;最后,将自相关信号作为期望响应。通过仿真分析对方法进行了验证,可以在低信噪比下准确构建期望响应进行LMS自适应滤波。

Aiming at the problem that the desired response error of the least mean square(LMS)adaptive filter constructed by spectral subtraction and spectrum method is large under the condition of low signal-to-noise ratio(SNR),based on the analysis of LMS adaptive filtering principle,an autocorrelation method is proposed to construct the desired response of LMS adaptive filter.Firstly,according to the characteristic that the noise is uncorrelated at different times,the input signal is delayed;then,in order to detect the periodic signal from the low signal-to-noise ratio environment,the autocorrelation of the delayed signal is calculated;finally,the autocorrelation signal is taken as the expected response.The method is verified by simulation analysis,and the desired response can be accurately constructed for LMS adaptive filtering under low SNR.