Abstract: Noise cancellation is one of the most successful applications of the wavelet transform. Its basic idea is to compare wavelet decomposition coefficients with the given thresholds and only keep those bigger ones and set those smaller ones to zero and then do wavelet reconstruction with those new coefficients. It is most likely for this method to treat some useful weak components as noise and eliminate them. Based on the cyclostationary property of vibration signals of rotating ma-chines, a novel wavelet based noise cancellation method is proposed. A numerical signal and an experimental signal of rubbing fault are used to test and compare the performances of the new method and the conventional wavelet based de-noising method provided by Matlab. The results show that the new noise cancellation method can efficaciously suppress the noise component at all frequency bands and has better de-noising performance than the conventional one.

Key words: Discrete wavelet transform, Noise cancellation, Vibration signal Rotating machine