基于科恩分布的地球物理信号的时频分析

The time-frequency analysis of geophysical signals based on Cohen distributions

在简要讨论几种科恩类广义双线性时频分布的基础上 ,探讨双线性时频分布的算法实现与仿真流程 ,进而模拟出地磁脉动信号的几种时频分布。同时还对 Pc脉动的几种双线性时频分布进行了比较 ,给出了相应的交叉项抑制和参数选取的方法。结果表明 ,在核函数参数选取适当的情况下 。

Time frequency distributions are two dimensional functions that indicate the time varying frequency content of one dimensional signal. Each bilinear time frequency distribution corresponds to a kernel function that controls its cross term suppression properties. After a brief discussion of several generalized bilinear time frequency distributions of Cohen's class, the algorithm realization and simulation flowchart is studied, then the WVD, ED, and GED of Pc geopulsation are simulated.Also the contrasts of Pc's several TFD are processed, and the methods of corresponding cross term suppression and parameter selection are given. Results show that in the condition that the parameters of kernel function are properly selected, the generalized bilinear time frequency representation is a powerful means in analysing geophysical signals.