中文说明：
介绍了Cohen类双线性时频分布并针对交叉干扰项影响无法完全消除的问题进行了重排时频变换以提取及分辨，含有白噪声和窄带周期干扰的局部放电信号。处理仿真和现场检测到的局部放电超声信号时根据白噪声和窄带，周期干扰信号在时域上的平稳性特性发现重排Cohen类时频变换方法不仅可以很好地将局放信号和背景噪声以 及窄带周期干扰信号分辨开来,而且大大减弱并抑制了交叉干扰项的影响，保持了更高的时频分辨率和时频聚集性，从而验证了重排Cohen类时频变换方法的有效性。
English Description：
The Cohen type bilinear time-frequency distribution is introduced, and the time-frequency transformation is rearranged to extract and distinguish PD signals with white noise and narrow-band periodic interference. According to the stationarity of white noise, narrow-band and periodic interference signals in time domain, it is found that the Cohen type time-frequency transform method can not only reduce the PD signal and background noise to noise, but also reduce the noise to noise