Application of short-time Fourier transform and Wigner-Ville distribution in time-frequency analysis of seismic wave

摘要

Seismic signal is a kind of non-stable signal,which can’t be analyzed suitably by classical Fourier analysis. Time-frequency analysis can analyze non-stationary signal in time-frequency domain and show out the distribution characteristics. WVD has perfect time-frequency concentration,but because it is a bilinear transformation,the existence of cross-terms is inevitable. STFT is linear transformation,has no cross-terms,but affected by the window size, it has bad time-frequency concentration. Based on the advantage of these two methods,we propose to obtain the time-frequency distribution by the combined method. This method can suppress the cross-term interference in WVD effectively,while keeping the excellent time-frequency concentration. By calculating simulation signal and actual data,the comparison result of STFT,WVD and the combined method indicates that the combination method is most suitable for computing the time-frequency distribution characteristics of earthquake waveform signal and more effective to detect the arrive time of P-waves.

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