HHT就是先将信号进行经验模态分解（EMD分解），然后将分解后的每个IMF分量进行Hilbert变换，得到信号的时频属性的一种时频分析方法。-HHT is a first signal to carry on the empirical mode decomposition (EMD decomposition), and then decomposed each IMF component of the Hilbert transform, get signal time-frequency

基于matlab的EMD(经验模态分解)(It gives some files on EMD by the team of G Rilling,and it show the algorithm on EMD in detail.)