This study presented an efficient time-frequency analysis scheme for vibration signals with transients. The scheme was developed based on the short-time Fourier transform with varying window size over time. The variable window size was determined by the local kurtosis. In regions where the kurtosis measured relatively high, a large window size was applied to improve the resolution of time-frequency image. Conversely, a small window size was applied to regions where the kurtosis measured relatively low. The method was tested by simulation signals and vibration signals in SNR 10 dB Gaussian noise. The results showed that the stationary or non-stationary signals with transients can be retrieved in time-frequency image.
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