说明：  本代码的方法是借助旋转不变技术估计信号参数(Estimation of Signal Parameters via Rotational Invariance Techniques)，现已成为谐波恢复（即正弦波个数及频率估计）的一种主要特征分解法。
(This code is to help the estimated ESPRIT signal parameters (Estimation of Signal Parameters via Rotational Invariance Techniques), has now become the harmonic retrieval (that is, the number and frequency sine wave estimated) of one of the main characteristics of decomposition.)