王丰华等提出的相位差分法的实现，主要用于信号处理中提取信号的瞬时频率。注意该方法只适用于单分量信号。另外一个是利用自相关法求瞬时频率-Wang Fenghua such as the phase difference method to achieve, mainly used for signal processing to extract the instantaneous frequency of the signal. Note that this method is only applicable to single-component signal