Patent ID: 6738739
Filing Date: 2004-05-18
Classification: G10L

Abstract:
A speech codec comprisinga failure detection circuit configured to initiate a frequency transformation of a speech signal using a harmonic model circuit when said failure detection circuit detects at least one of a long term pre-processing circuit failure, a long term processing circuit failure, and an irregular voice speech portion of the speech signal; a classifier configured to process parameters that identify a transition region between at least two portions of the speech signal, one of the at least two portions of the speech signal being a voiced portion; and a periodic smoothing circuit configured to smooth the transition region represented by at least one of a weighted representation of the speech signal, a residual signal, and the speech signal using at least one of an interpolated pitch lag and a constant pitch lag, the interpolated pitch lag being derived from a pitch track corresponding to the voiced portion of the speech signal, wherein the periodic smoothing circuit is configured to use at least one of a forward pitch extension and a backward pitch extension.