Real time decomposition of speech into modulated components

Motivated by the active process of the outer hair cell (OHC) in the mammalian inner ear, a real time decomposition of speech into modulated components is presented. A generalized phase lock loop (GPLL) was applied to decompose the speech signal into its envelope and positive instantaneous frequency (PIF) parts, which can be further processed and represented by timing information alone. A log-derivative operator is applied to the bandpass signal. Analytic and antianalytic components occupying non overlapping frequency bands are separated by filtering. The proposed algorithms are used to represent speech signals processed through a bandpass filter bank.