中文说明： emd是HHT（希尔伯特黄变换）的核心过程，该算法可以很好的处理非线性和非稳定信号数据，将复杂数据信号分解成简单信号的组合，目前已被应用到各个领域。
English Description：
EMD is the core process of the HHT (Hilbert Huang Transform), the algorithm can deal with the nonlinear and non steady signal data, complex data signal is decomposed into a combination of simple signal, has been applied to various fields.