The Study of The Denoising and the Trend Extraction Method of Signal

Based on the capability of orthogonal wavelet transform in de-noise and trend extract function of EMD, a new noise filter and trend extraction model is built up. Then, simulated data is used to test the method. The following conclusions are drawn from these tests: (1) Orthogonal wavelet transform and EMD method can better mitigate the random errors which hide in periodic signal; (2) For signal with linear trend, Orthogonal wavelet transform filtering method is superior to EMD. (3) For signal with nonlinear trend, theoretic analysis and simulation results show that the new noise filter and trend extraction model is superior to EMD and to union simply wavelet and EMD method. This method greatly improves accuracy of the extracted deformation.