Abstract:

 To improve the time-frequency concentration of the S-transform (ST) for the time-phase modulation (TPM), the generalized S-transform (GST) was adopted to the analysis of the TPM signal. Based on the window function of ST, a controllable parameter was added in the window function of GST. The window width for each frequency was optimized through the optimization of the added parameter and the time-frequency concentration was enhanced. The simulation shows that the GST approach can enhance the time-frequency concentration of the TPM signal in comparison to the standard ST, and the phase jump character of the TPM signal is retained which is helpful to the next processing of the signal detection.

Key words: S-transform, generalized S-transform, time-phase modulation, time-frequency distribution, time-frequency concentration