Patent ID: 6438517
Filing Date: 2002-08-20
Classification: G10L

Abstract:
A method of modeling the voiced or unvoiced characteristics of a segment of an input signal, comprising the steps of:receiving a pitch value associated with said input speech signal; comparing a synthesized speech signal to said input speech signal on a harmonic by harmonic basis; for each harmonic, determining whether said harmonic is voiced or unvoiced; counting the number of said harmonics that are voiced; calculating a cut-off frequency of said input speech signal, using the ratio of the results of said counting step and the total number of said harmonics, such that said cut-off frequency represents a frequency below which said speech signal is assumed to be voiced and above which said speech signal is comprised of both voiced and unvoiced speech; and generating a synthesized representation of said speech signal using said pitch value such that for each harmonic that falls below the cut-off frequency the harmonics are assumed to be voiced and for each harmonic above the cut-off frequency the harmonics are assumed to be mixed using both voiced and unvoiced energies for each harmonic.