Title :
An improved 2.4 kbps class-dependent CELP speech coder
Author :
Jiang, Yingbo ; Cuperman, Vladimir
Author_Institution :
Sch. of Eng. Sci., Simon Fraser Univ., Burnaby, BC, Canada
Abstract :
This paper presents an improved 2.4 kbps class-dependent CELP speech coder. The improved coder is based on our previous efforts on a 2.4 kbps CELP coder. New classification schemes in both open-loop and closed-loop are used. An extra transition class is used in the closed-loop classification. We developed a predictive LSP VQ to reduce LPC bit rate to as low as 18 bits/frame (30 ms) while maintaining low spectral distortion. Experimental results show that the quality of synthesized speech is improved. We also discuss the results obtained from class-dependent weighting filters, and a class-dependent postfilter
Keywords :
filtering theory; linear predictive coding; speech coding; speech intelligibility; speech synthesis; vector quantisation; vocoders; 2.4 kbit/s; 30 ms; LPC bit rate reduction; class-dependent CELP speech coder; class-dependent postfilter; class-dependent weighting filters; classification schemes; closed-loop classification; experimental results; low spectral distortion; open-loop; predictive LSP VQ; synthesized speech quality; Autocorrelation; Bit rate; Filters; Linear predictive coding; Mobile communication; Speech analysis; Speech coding; Speech synthesis; Stochastic processes; Vectors;
Conference_Titel :
Communications, 1995. ICC '95 Seattle, 'Gateway to Globalization', 1995 IEEE International Conference on
Conference_Location :
Seattle, WA
Print_ISBN :
0-7803-2486-2
DOI :
10.1109/ICC.1995.524436
