Patent ID: 6687666
Filing Date: 2004-02-03
Classification: G10L

Abstract:
A CELP type voice encoding device comprising:a noise codebook which can be searched in two modes; means for selecting one of said two modes in accordance with linear predictive analysis results, a pitch gain and a pitch cycle all of which are obtained as analysis results of an input voice wherein the number of pulses forming a noise code vector is switched between a first case where a variation in pitch cycle is small throughout continuous sub-frames and in a second case where the variation is not small throughout continuous sub-frames; and a sound source generating portion for quantizing a pitch gain using a multi-stage quantizer wherein a first stage quantizer quantizes a calculated pitch gain which is obtained immediately after an adaptive codebook is searched, while a second or higher stage quantizer quantizes a difference between the pitch gain which is determined through a closed loop searching after a sound source searching is completed and a quantized pitch gain which is obtained by said first stage quantizer, and said quantized pitch gain which is quantized by said first stage quantizer is used to select one of said two modes.