Title :
M-LCELP speech coding at 4 kbps
Author :
Ozawa, Kazunori ; Serizawa, Masahiro ; Miyano, Toshiki ; Nomura, Toshiyuki
Author_Institution :
C&C Inf. Technol. Res. Labs., NEC Corp., Kawasaki, Japan
Abstract :
This paper presents the M-LCELP (multi-mode learned code excited LPC) speech coder, which has been developed for the North American half-rate digital cellular systems. M-LCELP develops the following techniques to achieve high-quality synthetic speech at 4 kbps: (1) Multimode and multi-codebook coding, (2) Pitch lag differential coding with pitch tracking, (3) A two-stage joint design regular-pulse codebook with common phase structure in voiced frames, (4) An efficient vector quantization for LSP parameters, (5) An adaptive MA type comb filter to suppress excitation signal inter-harmonic noise. The MOS subjective test shows that 4.075 kbps M-LCELP synthetic speech quality is high, and that its quality is mostly equivalent to that for an 8 kbps North American full-rate VSELP coder
Keywords :
adaptive filters; cellular radio; digital radio; linear predictive coding; speech coding; speech synthesis; vector quantisation; vocoders; 4 kbit/s; LSP parameters; M-LCELP speech coding; MOS subjective test; North American full-rate VSELP coder; North American half-rate digital cellular systems; adaptive MA type comb filter; common phase structure; efficient vector quantization; excitation signal inter-harmonic noise; high-quality synthetic speech; multi-codebook coding; multimode coding; pitch lag differential coding; pitch tracking; speech coder; two-stage joint design regular-pulse codebook; voiced frames; Adaptive filters; Decoding; Information technology; Linear predictive coding; National electric code; Phase noise; Speech coding; Speech enhancement; Testing; Vector quantization;
Conference_Titel :
Acoustics, Speech, and Signal Processing, 1994. ICASSP-94., 1994 IEEE International Conference on
Conference_Location :
Adelaide, SA
Print_ISBN :
0-7803-1775-0
DOI :
10.1109/ICASSP.1994.389303
