Study Of Speech Codeing System Based On Conjugate Structure Algebraic Code Excited Linear Prediction

Conjugate Structure Algebraic Code Excited Linear Prediction was approved as ITU Recommendation in 1996 based on the project of USA AT&T, Japan NTT, Franc Telecom and Canada Sherbrooke University. CS-ACELP based on adapt Linear Prediction is one of the most sophisticate algorithms in the field of low bit rate speech coding. It synthesizes the excellence of wave coding and parameter coding, adopts Vector Quantity, Analyse- Synthesize, Perceptual Weighting ,therefore,gains good speech coding quality at 8kbit/s. CS-ACELP can be used in individual telecom, IPHONE,C/N, microwave telecom and ISDN.An 8kbit/s speech coding system is realized based on CS-ACELP. This system is simulated by using VC++6.0 in Windows2000. It is composed of encoder and decoder. Encoder makes up of Pre-processing, Linear Prediction and quantization, Perceptual Weighting, adaptive codebook search and fixed codebook search, quantization of gains and parameter coder. Decoder is hided in encoder in respect that this system adopts Analyse-Synthesize. Each of synthesis filter of decoder and encoder has same export bit flow. Decoder is contrary process of encoder. The result of simulating examination makes this system obtain good rebuilding speech coding quality which comply with G.729.An 8kbit/s speech coding system is designed in the text. It is also simulated by using VC++6.0 in Windows2000. The result of simulating examination make know this system obtain good rebuilding speech coding quality. In the end, original speech wave and rebuilding speech wave, original speech frequence and rebuilding speech frequence is listed.