Title :
Variable bit rate PARCOR-VQ hybrid Vocoder
Author :
Mizui, Kiyoshi ; Wakabayashi, Syuuichi ; Satoh, Masatoshi ; Minami, Yasuhiro ; Nakagawa, Masao
Author_Institution :
Fac. of Sci. & Technol., Keio Univ., Yokohama, Japan
Abstract :
The variable bit rate PARCOR-VQ hybrid vocoder uses the PARCOR scheme for unvoiced or transient periods and the VQ (vector quantization) scheme for voiced periods with a variable bit rate method. The ratio of voiced periods is much higher than that of unvoiced periods. Thus, it is expected that the average bit rate of the proposed vocoder will be much lower than that of the PARCOR vocoder. With respect to the accuracy of analysis-synthesis for unvoiced periods (important for recognition of words), the proposed vocoder is better than the VQ vocoder because it uses the PARCOR scheme for its periods. It is also expected that reconstructed speech of the proposed vocoder will be higher than that of the VQ vocoder. By computer simulation and listening tests, it was confirmed that the proposed vocoder, whose average bit rate is 919 b/s, has nearly the same quality as the 2.4 kb/s PARCOR vocoder
Keywords :
analogue-digital conversion; decoding; speech analysis and processing; vocoders; 2.4 kbit/s; 919 bit/s; PARCOR-VQ hybrid Vocoder; computer simulation; listening tests; speech quality; transient periods; unvoiced periods; variable bit rate vocoder; vector quantization; voiced periods; words recognition; Asynchronous transfer mode; Bit rate; Books; Computer simulation; Paper technology; Speech analysis; Speech coding; Speech synthesis; Testing; Vocoders;
Conference_Titel :
Global Telecommunications Conference and Exhibition 'Communications Technology for the 1990s and Beyond' (GLOBECOM), 1989. IEEE
Conference_Location :
Dallas, TX
DOI :
10.1109/GLOCOM.1989.64265
