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

Volume

i

fYear

1994

fDate

19-22 Apr 1994

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;

fLanguage

English

Publisher

ieee

Conference_Titel

Acoustics, Speech, and Signal Processing, 1994. ICASSP-94., 1994 IEEE International Conference on

Conference_Location

Adelaide, SA

ISSN

1520-6149

Print_ISBN

0-7803-1775-0

Type

conf

DOI

10.1109/ICASSP.1994.389303

Filename

389303