Application of the Generalized Demodulation Time-Frequency Analysis Method to Vibration Signals under Varying Speed

Instantaneous frequency is a primary parameter used for analyzing vibration signals of rolling bearings under harsh working conditions, which contains rich information besides the rotating speeds of the shaft. Such vibration signals exhibits characteristics of non-stationary and multi-components. The generalized demodulation time-frequency analysis approach is a novel signal processing method, which is suitable for processing non-stationary and multi-component signals. Its novelty lies in that the signal whose time-frequency distributions are curved paths can be transformed into that whose time-frequency distributions are linear paths paralleling time axis by using generalized demodulation. In this paper, to deal with the vibration signals under variable working speed condition, the generalized demodulation as well as a band-pass filter is used to separate the interested component from original vibration signal. The analysis results demonstrate the validity of the proposed approach.