Title :
The adaptive multi-rate speech coder
Author :
Ekudden, E. ; Hagen, R. ; Johansson, I. ; Svedberg, J.
Author_Institution :
Ericsson Res., Ericsson Radio Syst. AB, Stockholm, Sweden
Abstract :
In this paper, we describe the adaptive multi-rate (AMR) speech coder currently under standardization for GSM systems as part of the AMR speech service. The coder is a multi-rate ACELP coder with 8 modes operating at bit-rates from 12.2 kbit/s down to 4.75 kbit/s. The coder modes are integrated in a common structure where the bit-rate scalability is realized mainly by altering the quantization schemes for the different parameters. The coder provides seamless switching on 20 ms frame boundaries. The quality when used on GSM channels is significantly higher than for existing services
Keywords :
adaptive codes; algebraic codes; cellular radio; linear predictive coding; speech coding; vector quantisation; vocoders; 4.75 to 12.2 kbit/s; ACELP coder; AMR speech service; GSM channels; adaptive codebook; adaptive multi-rate speech coder; algebraic CELP coder; algebraic codebook; bit-rate scalability; quantization schemes; seamless switching; Background noise; Bit rate; Europe; Filters; GSM; Quantization; Scalability; Speech coding; Speech enhancement; Standardization;
Conference_Titel :
Speech Coding Proceedings, 1999 IEEE Workshop on
Conference_Location :
Porvoo
Print_ISBN :
0-7803-5651-9
DOI :
10.1109/SCFT.1999.781503
