基于FRFT的Wigner-Ville分布交叉项抑制方法

针对多分量线性调频信号的魏格纳-维尔分布(Wigner-Ville Distribution,WVD)交叉项干扰问题,提出一种抑制交叉项的方法。该方法利用分数阶傅里叶变换(Fractional Fourier Transform,FRFT)在最佳FRFT域中对给定的线性调频信号具有最好的能量聚集性,将多分量线性调频信号在FRFT域上分解为若干个单分量信号,线性叠加单分量信号的WVD,从而达到抑制交叉项的效果。此外,当多分量线性调频信号为周期信号时周期间存在干扰,进一步提出了在基于FRFT的WVD交叉项抑制方法中增加周期遮蔽处理。仿真结果表明,在保持较高的时频分辨率时,该方法能够有效抑制交叉项,并且有一定的抗噪声能力。

Wigner-Ville Distribution Cross Terms Suppression Method Based on FRFT

A method for suppressing cross terms is designed for multi-component linear frequency modulation (LFM) signals.Fractional Fourier transform (FRFT) is used to obtain the best energy aggregation for LFM signal in the optimal FRFT domain.In order to suppress the cross terms of the multi-component LFM signals,the multi-component LFM signals are decomposed into several single-component signal in the FRFT domain,and the Wigner-Ville distribution of single-component signal is linearly superposed.In addition,a period masking approach based on FRFT is further proposed to suppress the cross terms with regard to period signals.The simulation results show that the proposed method can effectively suppress cross terms and has a certain anti-noise ability while maintaining a high time-frequency resolution.