经验模式分解程序，由我们课题组编写，计算本征模函数-emd program, our group write,compute imf

集合经验模态分解主要用于信号分解与降噪，为后期信号特征提取提供理论基础-The set of EMD is mainly used for signal decomposition and denoising, which provides a theoretical basis for signal feature extraction.