说明：  HHT主要内容包含两部分，第一部分为经验模态分解（Empirical Mode Decomposition，简称EMD），它是由Huang提出的；第二部分为Hilbert谱分析（Hilbert Spectrum Analysis，简称HSA）。简单说来，HHT处理非平稳信号的基本过程是：首先利用EMD方法将给定的信号分解为若干固有模态函数（以Intrinsic Mode Function或IMF表示，也称作本征模态函数），这些IMF是满足一定条件的分量；然后，对每一个IMF进行Hilbert变换，得到相应的Hilbert谱，即将每个IMF表示在联合的时频域中；最后，汇总所有IMF的Hilbert谱就会得到原始信号的Hilbert谱。
(The main content of HHT includes two parts. The first part is Empirical Mode Decomposition (EMD), which was proposed by Huang, and the second part is Hilbert Spectrum Analysis (HSA). Simply speaking, the basic process of HHT processing non-stationary signals is: firstly, the given signal is decomposed into several intrinsic mode functions (represented by Intrinsic Mode Function or IMF, also known as intrinsic mode functions), which are components satisfying certain conditions; secondly, Hilbert transform is applied to each IMF. The corresponding Hilbert spectrum is obtained, that is, each IMF is represented in the joint time-frequency domain; finally, the Hilbert spectrum of the original signal is obtained by summing up the Hilbert spectrum of all IMFs.)