Comparison of performance between discrete S transform frequency-domain algorithm and time-domain

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.