fft

代码说明：

  描绘了一个三种频率四个端点的图，行这个图纸呢更可以进行小波变换和HHT你是内环，通过结果说明HHt谱与时间的关系(Depicts a figure three frequencies of the four endpoints, line drawings that can do more wavelet transform and inner HHT you are, by the results illustrate the relationship between the spectrum and time HHt)