Experimental study on rationality of ‘Hilbert envelope’ based on Empirical Mode Decomposition

In auditory science, Hilbert transform (HT) was used for decomposition of temporal envelope (E) and fine structure (TFS) [1]. Sometimes the envelope is called `Hilbert envelope´. Although HT has rigorous mathematical definition, it has little intrinsic physical relationship with E or TFS. Aims to investigate the rationality of that method for E or TFS extraction, this study introduced Empirical Mode Decomposition (EMD). Experiment results showed that HT was usually rational for envelope extraction of narrow-band signals, but not for that of non-narrow-band signals. However, please keep in mind that this conclusion is not a definite proof but a experimental implication under the theory of EMD.