用斜率鉴频法求取地震信号的瞬时频率

EXTRACTION OF INSTANTANEOUS FREQUEN-CIES BY SLOPE DISCRIMINATION

西南石油学院勘探系

地震波的频率参数是地震波重要的动力学特征.用希尔伯特变换的方法可以求出地震信号的瞬时频率.但是,希尔伯特变换滤波因子是衰减较慢的无穷序列,这给求取仅持续两三个相位的地震于波的瞬时频率带来困难.本文提出用斜率鉴频的办法求取瞬时频率,给出具有最短滤波因子的鉴频滤波器设计,最后将理论试算的结果和希尔伯特变换算法的结果加以比较.

Seismic frequency is an important dynamic character of seismic wave. The instantaneous frequency of seismic signal could be derived by Hil-bert transformation. But the filtering factor used in Hilbert transformation is an infinite sequence of slowly attenuating. This would make it very difficult to extract the instantaneous frequencies of the wavelets with only 2 or 3 maximum(minimum) extremes. In this paper, a new technique for extracting the instantaneous frepuencies by slope discrimination was suggested. A plan for designing a frequency discrimination filter with the shortest filtering factor was worked out. Results from computation and Hilbert transformation were compared with each other at the end of this paper.