线调频小波WVD用于非平稳信号分析研究

The analysis of chirplet wigner-ville distribution for non-stationary signal

WVD(wigner-ville distribution)是一种常见的时频表示方法。为了消除WVD中出现的交叉项,提出了一种新的时频表示方法:线调频小波WVD(chirplet wigner-ville distribution,CWVD)。利用多分量的复杂信号可以通过频率旋转算子转换得到若干个单一频率的简单信号的特点,将WVD应用在频率旋转后的信号上,使用频移算子偏移信号的瞬时频率。由多项式函数或者样条函数逼近估计的IFs(instantaneous frequencies)来计算算子的参数。通过测试信号验证了多项式CWVD和样条CWVD的有效性。CWVD在抑制交叉项方面较其他时频方法具备更好的性能,且能量集中性能突出。

Wigner-Ville Distribution is a common time-frequency representation method.In order to eliminate the cross-term in WVD,a new method of time-frequency representation named Chirplet Wigner-Ville Distribution is proposed.The multi-component signal can be transformed into several simple mono-frequency signals by frequency rotating operators,and WVD is applied to the rotated signals,then frequency shift operators are utilized to relocate the signal’s IFs.The operators’parameters come from the estimation of the IFs which are approached with a polynomial functions or spline functions.The effectiveness of the polynomial CWVD and spline CWVD is verified by the test signal,and the excellent performance of CWVD is revealed by comparing with other time-frequency representation methods.