一种多分量信号分解方法:时频滤波分解

A Multicomponent Signal Decomposition Method:Time-Frequency Filtering Decomposition

为解决目前信号分解分量时频域紧邻、重叠和间歇性复杂时频特征的多分量非平稳、非线性信号时,分解困难和效率低的问题,本文提出了一种基于信号时频分布的多分量非平稳信号分解方法——时频滤波分解(Time-Frequency Filtering Decomposition,TFFD). TFFD通过拟合所选反映信号中各分量时频瞬时特征与规律的时频域基准数据点,得到与分量实际瞬时频率(Instantaneous Frequency,IF)一致的拟合IF曲线,并以拟合IF曲线的时频坐标为基础,设置距离阈值条件确定分量在时频图上的分布区域,构造以拟合IF曲线时频坐标为中心频率、分布区域频宽为通带宽度的时频滤波器组,实现对多分量信号的时频滤波分解.通过对具有代表性时频特征的仿真和实际信号分析,并与经典信号分解方法对比,证明了TFFD方法优良的分解能力和分解效率.

The problems of difficulty and low efficiency in decomposing multicomponent nonstationary nonlinear sig⁃nal with complex time-frequency characteristics such as contiguity,overlap and intermittency in time-frequency domain are solved.Based on the time-frequency distribution of signal,a multicomponent nonstationary signal decomposition method called time-frequency filtering decomposition(TFFD)is proposed.TFFD gets the fitting IF curve which is consistent with the instantaneous frequency(IF)of the components by fitting the time-frequency datum points which can reflect the instan⁃taneous characteristics and laws of the components in the signal.Based on the time-frequency coordinates of fitting IF curve,the distribution area of component is determined by setting the distance threshold condition.Thus,a time-frequency filter bank is constructed,which is based on fitting IF curve time-frequency coordinates as the central frequency and the bandwidth of distribution area as the passband width,to achieve time-frequency filtering decomposition for multicomponent signal.Through the analysis of the simulation and the actual signal with the representative time-frequency characteristics,and the comparison with the classical signal decomposition methods,it is proved that the TFFD method has good decompo⁃sition ability and efficiency.