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 appl