Patent ID: 6456964
Filing Date: 2002-09-24
Classification: G10L

Abstract:
A method for coding and decoding a quasi-periodic speech signal that is transmitted from a transmission source to a receiver, wherein the speech signal is represented by a residual signal generated by filtering the speech signal with a Linear Predictive Coding (LPC) analysis filter, and wherein the residual signal is divided into frames of data, comprising the steps of:extracting a current prototype from a current frame of the residual signal; calculating a first set of parameters which describe how to modify a previous prototype such that said modified previous prototype approximates said current prototype; selecting one or more codevectors from a first codebook, wherein said codevectors when summed approximate the difference between said current prototype and said modified previous prototype, and wherein said codevectors are described by a second set of parameters; transmitting said first set of parameters and said second set of parameters to the receiver; forming a reconstructed current prototype at the receiver based on said first set of parameters, said second set of parameters, and a reconstructed previous prototype; interpolating over the region between said reconstructed current prototype and said reconstructed previous prototype to form an interpolated residual signal; and synthesizing an output speech signal based on said interpolated residual signal.