将周期图、自相关、协方差、改进协方差、Burg五种谱分析法封装为函数，并调用之对三个不同的信号源进行谱估计。-Encapsuler 5 methods of frequency uation (Periodogram, COR, COV, MCOV, Burg) as functions, and use them to do frequency uation of three different signals.