Title :
A high quality 4 kb/s multiple pulse-dispersion ACELP speech coder
Author :
Li, Yue ; Tang, Kun ; Cui, Huijuan
Author_Institution :
State Key Lab. on Microwave & Digital Commun., Tsinghua Univ., Beijing, China
Abstract :
Pulse dispersion is a very efficient technology to improve the speech quality of a low bit-rate code-excited linear-prediction (CELP) coder. A novel high quality 4 kb/s algebraic CELP (ACELP) speech coder is presented. Different pulse-dispersion technologies are applied to both encoder and decoder to reduce the adverse effects of the sparse algebraic codebook vector and improve the perceptual quality of noise-like and unvoiced speech. Also, pitch preemphasis technology is introduced to improve the robustness of pitch analysis. An harmonic-enhancement technology is introduced to enhance the performance of the fixed codebook further. Informal tests show that the speech quality of the presented 4 kb/s speech coder is very close to that of the 4.75 kb/s coder of ETSI AMR.
Keywords :
adaptive filters; algebraic codes; high-pass filters; linear predictive coding; speech coding; vocoders; 4 kbit/s; 4.75 kbit/s; adaptive post filter; algebraic CELP speech coder; code-excited linear-prediction coder; harmonic-enhancement technology; high-pass filter; multiple pulse-dispersion speech coder; noise-like speech; perceptual quality; pitch analysis; pulse-disperse filter; sparse algebraic codebook vector; unvoiced speech; Adaptive filters; Decoding; Digital communication; Distortion measurement; Laboratories; Noise reduction; Noise robustness; Speech analysis; Speech coding; Speech enhancement;
Conference_Titel :
Communications, Circuits and Systems, 2004. ICCCAS 2004. 2004 International Conference on
Print_ISBN :
0-7803-8647-7
DOI :
10.1109/ICCCAS.2004.1346331
