emd

代码说明：

  emd分解是对原始信号分解得到各个分量的过程，它的核心是通过找出信号的极大值和极小值点拟合出上下包络从而得到平均包络。(The emd decompose each component of the process of decomposition of the original signal, its core is by identifying the maximum and minimum points of the signal fitting upper and lower envelopes in order to get the average envelope.)