广义指数分布及其在地球物理信号时频分析中的应用

Time-frequency analysis with the generalized exponential distribution kernel and its application to geophysical signal processing

广义指数分布是Ｃｏｈｅｎ类二次时频表示的一种，同传统的短时傅立叶交换和Ｗｉｇｎｅｒ－Ｖｉｌｌｅ分布相比，它具有更加优良的时频分析特性。本文利用广义指数分布ＧＥＤ分析了地磁脉动信号的时频分布特征，高分辨率地再现了地磁信号的频谱随时间的演变过程，同时本文还探讨了ＧＥＤ分布中参数选取的方法。本文结果表明，在参数Ｍ，Ｎ，ζ１，τ１；选取适当的情况下，ＧＥＤ可以达到既压缩多分量信号中的交叉干扰而同时又不损失自项时频分辨率的良好效果，是分析地球物理信号的有力工具。

The generalized exponential distribution is one of the bilinear time-frequency representation of Cohen's class, it has many good qualities in time-frequency analysis in comparison to the traditional STFT and Wigner-Ville distribution.GED has been used to analysis many kinds of unsteady signals. In this paper, the characteristic of geomagnetic pulsations will be analyzed by the GED and we will see an exact picture of the time-frequency evolution of geopulsations and we also present a method to select the parameters in the GED, Results show that, if the parameter M,N.ζ1,τ1 are selected properly, the GED can achieve cross-term reduction and auto-term preservation simultaneously and it is a powerful tool in geophysical signal processing.