Demodulation Analysis And Application Research Of Multi-Component Modulation Signals In Mechanical Vibration Signals

Most of the mechanical equipment fault vibration signals are multi-component AM-FM signals. Through the multi-component modulated signal demodulation analysis, it can effectively extract fault feature information of signal, achieving fault diagnosis of mechanical equipment.For the traditional demodulation method is prone to the problem of interference spectrum peak in the demodulation of multi-component modulation signals and focuses on the properties of complex Morlet wavelets. It can be inferred that complex Morlet wavelet transform coefficients with the function of envelope detection, based on the realization of the complex Morlet wavelet envelope demodulation method. The validity and feasibility of the complex Morlet wavelet envelope demodulation method is verified by the demodulation analysis of the simulation signals. Experimental results show that the demodulation method applies not only to single component modulation signals, also apply to the multi-component modulated signals.The imaginary part of the wavelet cluster transform coefficients is the Hilbert transform of its real part, which can be used to implement envelope demodulation. Based on wavelet cluster of band-pass filter and envelope demodulation method, it will take pass filtering and envelope demodulation to unify, simplifying the operation steps, The method is used in the multi-component modulated signal demodulation analysis, which can easily extract the multi-component modulated signal at any frequency within the signal component modulated information.A wavelet cluster can also be used as a comb filter with comb filtering properties. The wavelet cluster comb filter not only can effectively suppress all kind of noise interference components outside the modulation frequency band, but also can effectively inhibit the noise in the modulation frequency band. Compared with the traditional demodulation method, a comb filter and envelope demodulation method is applied to the demodulation analysis of multi-component signals. The vibration data of rolling bearing in the laboratory and the vibration data of industrial field wind turbine are analyzed, and the results are compared with the results of other demodulation methods. The experimental results show that the demodulation spectrum obtained by the wavelet cluster comb filter envelope demodulation method is the best, which has a better inhibitory effect on the interference spectrum.