关键词: 时-频分析, 离散S变换, 时域算法, 频域算法, 周期性

Abstract: With excellent time-frequency combination, S transform has been extensively used in the field of signal processing. In physical system, S transform can be finished with discrete numerical calculation, providing a correct basis for analyzing and solving problems. The discrete S transform can be implemented in two ways which are frequency-domain and time-domain and the former being used widely. There are some obvious differences on signal spectrograms by different algorithms, but the related references about it cannot be found. The frequency-domain algorithm of discrete S transform is usually implemented by FFT and IFFT. Due to the inherent periodicity of Fourier transform, the ends of signal spectrogram generated by frequency-domain algorithm have false frequency information, interfering signal time-frequency analysis. Based on the study of basic principles of S transform, this paper proposes a time-domain algorithm of discrete S transform, which overcomes the shortages of the frequency-domain algorithm and can map signal time-frequency distribution more accurately. The paper validates the algorithm of time-domain by introducing comparative tests, and gives using recommendations. The frequency-broadening processing of the algorithm is used real seismic data, and the result indicates that this method can availably improve seismic signal resolution both in time and frequency domain.

Key words: time-frequency analysis, discrete S transform, time-domain algorithm, frequency-domain algorithm, periodicity