Patent ID: 6510407
Filing Date: 2003-01-21
Classification: G10L

Abstract:
A method for coding speech comprising the steps of:sampling an input speech to produce a plurality of speech samples; determining coefficients for a speech synthesis filter, including grouping said speech samples into a first set of groups and computing LPC coefficients for each such group, whereby said filter coefficients are based on said LPC coefficients; producing excitation signals, including: grouping said speech samples into a second set of groups; categorizing each group in said second group into an unvoiced, voiced or onset category; and for each group in said unvoiced category, producing said excitation signals based on a gain/shape coding scheme; for each group in said voiced category, producing said excitation signal by further categorizing such group into a low-pitch voiced group or a high-pitched voice group, wherein for low-pitched voice groups said excitation signals are based on a long term predictor and a single pulse, and for high-pitched voice groups said excitation signals are based on a sequence of pulses which are spaced apart by a pitch period; for each group in said onset category, producing said excitation signals by selecting at least two pulses from said group; and encoding said excitation signals.