Filter bank properties of envelope modified EMD methods

Abstract

Envelope modified versions of the empirical mode decomposition (EMD) method such as the B-spline interpolation-based EMD (B-EMD) method and cardinal spline interpolation-based EMD (C-EMD) method have been proposed recently for purpose of improving its effectiveness. To shed further light on their performance, the behaviours of these EMD-type methods in the presence of white Gaussian noises are investigated in this study based on extensive numerical experiments. Similarly to the EMD method, it turns out that the envelope modified EMD methods also act as filter banks essentially. However, the spectra among the first several intrinsic mode functions of the B-EMD method have fewer overlaps than those of the EMD and C-EMD methods, which indicate that the B-EMD method has a better ability to alleviate the mode mixing problem for signals with higher frequencies. On the other hand, the C-EMD method is shown to perform better than the EMD and B-EMD methods on separating tones with lower frequencies.