Wavelet Transform Time-Frequency Analysis Method for the Time-Varying Non-stationary Signals

For the strong non-linear, non-Gauss and non-stationary vibration signal of rotating machinery, a time-frequency analysis method based on the wavelet transform technology and the traditional time-frequency analysis technology is proposed. In the method, the wavelet transform technology is used to achieve the signal decomposition of the variable scale time-frequency atom (wavelet functions), and FFT is used to complete time-frequency analysis. With the method, a simulation for the assumed non-stationary shock-vibration signal on bearing-rotor system is carried out. The simulated bearing vibration signal with the shock response component is analyzed, and the vibration characteristics in the time domain and frequency domain are obtained. The results show that the method can more quickly and accurately extract the non-stationary signal characteristics (frequency and magnitude), and its accuracy is higher than that of FFT and STFT.