说明：  Hilbert-Huang变换(HHT)是一种新的非平稳信号处理技术，该方法由经验模态 分解(EMD)与Hilbert谱分析两部分组成。任意的非平稳信号首先经过EMD方法处理后被分解为一系列具有不同特征尺度的数据序列，每一个序列称为一个固有模态函数(IMF)，然后对每个IMF分量进行Hilbert谱分析得到相应分量的Hilbert谱，汇总所有Hilbert谱就得到了原信号的谱图。该方法从本质上讲是对非平稳信号进行平稳化处理，将信号中真实存在的不同尺度波动或趋势逐级分解出来，最终用瞬时频率和能量来表征原信号的频率含量。
(Hilbert-Huang transform (HHT) is a new non-stationary signal processing techniques, the method by the empirical mode decomposition (EMD) and Hilbert spectral analysis of two parts. Any non-stationary signals are first processed through the EMD method after being broken down into a series of data sequences with different characteristic scales, each sequence is called an intrinsic mode function (IMF), then Hilbert spectrum analysis of each component of the corresponding IMF component of the Hilbert spectrum, Hilbert spectrum is obtained summary of all the spectrum of the original signal. This method is essentially non-stationary signals smooth process, different scales of the signal in real fluctuation or trend gradually break out, ultimately the instantaneous frequency and energy to characterize the frequency content of the original signal.)