A variable bit rate operation of LD-CELP mainly for VBD applications in DCME

Author

Shapira, Inbar ; Simchony, Tal ; Sourani, Sasson ; Piasetzky, Joshua

Author_Institution

ECI Telecom Ltd., Israel

fYear

1997

fDate

7-10 Sep 1997

Firstpage

73

Lastpage

74

Abstract

This paper describes the candidate algorithm for Annex J of ITU-T Rec. G.728. The algorithm achieves compression and near transparent transmission of VBD signals such as V.34 @ 19200 bps (and up to 21600 bps under moderate analog impairments conditions) using a 40 kbit/s transmission rate. Additionally the algorithm provides toll speech quality and smooth mode-switching (speech-to-data/data-to-speech) during voice and signaling signals. The main novelty of the algorithm is the application of trellis coded quantization (TCQ) approach to codebook search that results in sufficient quantization gain, lower complexity (than LD-CELP), and maintains the same algorithmic delay of 5 samples (0.625 msec)

Keywords

code standards; data communication; data compression; delays; linear predictive coding; quantisation (signal); speech codecs; speech coding; speech processing; telecommunication standards; trellis codes; voice communication; 19200 bit/s; 21600 bit/s; 40 kbit/s; Annex J; DCME; ITU-T Recommendation G.728; LD-CELP; TCQ; V.34; VBD applications; VBD signals; algorithm; algorithmic delay; analog impairments conditions; codebook search; data communication; decoder; mode-switching; quantization gain; signaling signals; toll speech quality; transmission rate; transparent transmission; trellis coded quantization; variable bit rate operation; voice signals; Bit rate; Convolution; Convolutional codes; Decoding; Equations; Filters; Linear predictive coding; Speech; Switches; Viterbi algorithm;

fLanguage

English

Publisher

ieee

Conference_Titel

Speech Coding For Telecommunications Proceeding, 1997, 1997 IEEE Workshop on

Conference_Location

Pocono Manor, PA

Print_ISBN

0-7803-4073-6

Type

conf

DOI

10.1109/SCFT.1997.623902

Filename

623902