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| Research on a Hybrid Time-frequency Method based on the optimal Morlet wavelet and Auto terms Window |
| Liu Wenyi;Tang Baoping; Chen Renxiang |
| (The State Key Laboratory of Mechanical Transmission,Chongqing University, Chongqing 400030, P.R.China) |
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Abstract A new hybrid time-frequency method was put forward in this paper based on the optimal Morlet wavelet and auto terms window. The Morlet wavelet, for its shape was similar to the mechanical shock signals, was improved by adding two parameters which decided the shape of the mother wavelet. The added parameters and the appropriate scale parameter for the continuous wavelet transformation were designed by the Cross Validation method and the Minimum Shannon Entropy method. Then, the useful components of the signal analyzed can be obtained by the improved Morlet wavelet de-noising method. Finally, the auto terms window based on the Smoothed Pseudo Wigner-Ville distribution (SPWVD) spectrum was used as a window function to remove the cross terms in Wigner-Ville distribution (WVD). The simulation and fault diagnosis experimental results show that the proposed method has a good de-nosing performance and is effective in removing the cross terms and fault feature extraction.
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Received: 10 June 2009
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2010, Vol. 29 
