实现功率谱估计的函数：



Arburg:用Burg算法估计AR模型的参数； Arcov: 用协方差法估计AR模型的参数；

Armcov:用改进的协方差法估计AR模型的参数；

Aryule:用Yule_Walker算法估计AR模型的参数；

-To achieve a function of power spectrum estimation: Arburg: AR with Burg algorithm to estimate model parameters　Arcov: AR covariance method to estimate the model parameters　Armcov: an improved method to estimate the covariance parameters of AR model　Aryule: with Yule_Walker algorithm to estimate AR model parameters