An implementation of a variable rate codec based on ADPCM with multi-quantizer (ADPCM-MQ)

Author

Tomita, Yoshihiro ; Iseda, Kohei ; Taniguchi, Takafumi ; Unagami, Shigeyuki

Author_Institution

Fujitsu Lab. Ltd., Kawasaki, Japan

fYear

1988

fDate

28 Nov-1 Dec 1988

Firstpage

1080

Abstract

Discusses an implementation of an experimental variable bit rate codec (VRC) based on adaptive differential pulse code modulation with a multiquantizer (ADPCM-MQ) that processes speech signals at 16 kb/s to 48 kb/s. The authors propose a method for the combined use of constant SNR (signal/noise ratio) and constant noise to determine optimum bit/rate control of the VRC. This algorithm was implemented using six digital signal processor chips. The average bit rate of the prototype codec for the telephone voice channel was about 23 kb/s, including supplementary information, and a quality better than that specified in G.721 (32 kb/s ADPCM) was observed

Keywords

analogue-digital conversion; codecs; pulse-code modulation; 16 to 48 kbit/s; ADPCM-MQ; adaptive differential pulse code modulation; algorithm; bit/rate control; constant SNR; constant noise; digital signal processor chips; multiquantizer; signal/noise ratio; speech quality; telephone voice channel; variable bit rate codec; Bit rate; Digital signal processors; Modulation coding; Pulse modulation; Signal processing; Signal processing algorithms; Signal to noise ratio; Speech codecs; Speech coding; Speech processing;

fLanguage

English

Publisher

ieee

Conference_Titel

Global Telecommunications Conference, 1988, and Exhibition. 'Communications for the Information Age.' Conference Record, GLOBECOM '88., IEEE

Conference_Location

Hollywood, FL

Type

conf

DOI

10.1109/GLOCOM.1988.26001

Filename

26001