Title :
A 7 kHz bandwidth, 32 kbps speech coder for ISDN
Author :
Quackenbush, Schuyler
Author_Institution :
AT&T Bell Lab., Murray Hill, NJ, USA
Abstract :
The author describes a voice codec with a 20 to 7000 Hz bandwidth that compresses to 2 bits per sample at a sample rate of 16 kHz. The algorithm is based on a transform coder that employs dynamic bit allocation in the frequency domain using a perceptual noise weighting criterion, and by Huffman compression of the quantized transform signal. It is well suited to ISDN (integrated services digital network) channels since it permits two coded voice signals to be carried on a single 64 kbps ISDN B channel. A two-channel coder has been implemented in real-time using three AT&T DSP32C signal processors and runs on the public switched ISDN network. The one-way communication delay of this hardware is 75 msec
Keywords :
ISDN; encoding; speech analysis and processing; vocoders; 20 Hz to 7 kHz; 32 kbit/s; 75 msec; AT&T DSP32C signal processors; Huffman compression; ISDN B channel; dynamic bit allocation; frequency domain; integrated services digital network; one-way communication delay; perceptual noise weighting criterion; public switched ISDN network; quantized transform signal; transform coder; two coded voice signals; voice codec; Bandwidth; Bit rate; Codecs; Communication switching; Delay; Frequency domain analysis; ISDN; Signal processing; Signal processing algorithms; Speech;
Conference_Titel :
Acoustics, Speech, and Signal Processing, 1991. ICASSP-91., 1991 International Conference on
Conference_Location :
Toronto, Ont.
Print_ISBN :
0-7803-0003-3
DOI :
10.1109/ICASSP.1991.150264
