Research on instantaneous feature of non-stationary signal based on hilbert-huang transform and wavelet packet decomposition

An improved analysis method for non-stationary signal based on Hilbert-Huang transform (HHT) and the wavelet packets decomposition (WPD) is presented in this paper. First, the WPD is used to decompose the signal into a set of narrow band signals prior to HHT. Second, the suitable threshold value is selected for each decomposed components. Last, HHT is only applied to those components which wavelet coefficients are larger than the threshold value. The proposed method can not only solve the shortcoming of empirical mode decomposition (EMD) in HHT, but also decrease the unnecessary noise influence upon the later decomposition, and reduce the computing quantities and the decomposition layers of EMD. The results of simulation and experiment indicate the proposed method is very effective