说明：  用Matlab实现现代功率谱估计，主要有Levinson法，Burg法，协方差法及修正协方差法，四种方法的结果放到一起进行比较，有详细的注释
(Using Matlab implementation of modern power spectrum estimation, the main has Levinson Law, Burg method covariance method covariance method, and the amendment, four ways to put together the results of comparison, there is a detailed explanatory note)