基于扫频滤波器线性调频信号的滤波算法

An Adaptive Filter Method of LFM Signal Based on Swept Filter

摘要:

研究了白噪声环境下线性调频信号的自适应滤波问题.提出一种线性调频信号(LFM)自适应滤波算法.该算法利用分数阶傅里叶变换将LFM信号转化为正弦信号,在分数阶傅里叶域进行自适应滤波,利用分数阶傅里叶反变换得到滤波后的时域信号.分数阶的滤波器可以使用扫频滤波器替代.性能分析表明,该算法的滤波效果取决于自适应滤波器的效果,在使用最下均方(LMS)算法时,步长的选取决定了滤波器的性能,在实际应用中必须按需选取.仿真表明该算法效果明显,计算方便.

Abstract:

An adaptive filter method of linear frequency modulation(LFM) signal in white noise is discussed,and a LFM signal is produced.The LFM signal is transformed to sinusoid signal by Fourier reverse transform(FRFT).The adaptive filter,which can be replaced by swept filter,is implemented in domain u,and the filtered signal is gained with the fractional FRFT.A detailed analysis of the method performance proves that the method performance depends on adaptive filter.When LMS algorithm is used,the performance of ALE is decided by step parameter,and the step parameter is selected in practice.At last,Simulation results show that this filtering algorithm is simple to computated and easy to implement.