Abstract：The basic principles of S transform were briefly discussed. The simulation experiment was conducted to compare the time-frequency analysis and signal detection capabilities of short-time Fourier transform and S transform. Comparisons show that S transform is a more effective time-frequency analysis method for non-stationary signals. Taking a six-cylinder engine as an example, noise signals from the engine front end and top surface were recorded. S transform was adopted to analyze the recorded noise signals in time-frequency domain. The energy distribution laws of noise signals and the variation of frequency components with time were subsequently analyzed. According to the engine structural characteristics, the generation cause of the more prominent frequency components was discussed. The analysis showed that S transform is more suitable for investigating the time-frequency characteristics of noise signals.
2008, Vol. 29 
