产生脉内Frank相位编码调制信号，并对其进行平方、四次方变换，利用四次方FFT结果为单频信号的特点完成调制识别，最后绘图观察其瞬时相位曲线。-Generating pulse code modulation signal within Frank polyphase, and its square, four square transformed by FFT results for the fourth power single-frequency signal modulation characteristics of complete identification, finally drawing to observe the instantaneous phase of the curve.