Comparison of Three Time-Frequency Analysis Techniques for Engine Cylinder Head Vibration Signals under Stable Conditions

The precise relationships among three joint time-frequency analysis techniques,i.e.analytic wavelet transform(AWT),S transform(ST),Gaussian windowed STFT,were derived,the numerical implementations of AWT and ST were united,then the characteristics of IC engine vibration signals under stable conditions were examined.The three techniques were applied to real signals to be compared.It shows that equal resolution of STFT is not necessarily an adverse aspect for time-frequency analysis of these signals,to the contrary,it could locate the frequency components excited by transient events more correctly without much sacrifice in time resolution.