Patent ID: 7383176
Filing Date: 2008-06-03
Classification: G10L

Abstract:
1. A CELP-based speech encoder that performs encoding by decomposing one frame into a plurality of subframes, comprising: an LPC synthesizer that obtains synthesized speech by filtering an adaptive excitation vector and a stochastic excitation vector stored in an adaptive codebook and in a stochastic codebook using LPC coefficients obtained from input speech; a gain calculator that calculates gains of said adaptive excitation vector and said stochastic excitation vector; a parameter coder that performs vector quantization of the adaptive excitation vector and the stochastic excitation vector obtained by comparing distortions between said input speech and said synthesized speech; a pitch analyzer that calculates correlation values by performing pitch analyses of the plurality of subframes before performing an adaptive codebook search for a first subframe and finds a value most approximate to a pitch period using said correlation values; and a search range setter that determines a lag search range using at least one of said correlation values and a value calculated using said correlation values.