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APVQ encoder applied to wideband speech coding

By Josep Salavedra Molí and Enrique José Masgrau Gómez


The paper describes a coding scheme for broadband speech (sampling frequency 16 KHz). The authors present a wideband speech encoder called APVQ (adaptive predictive vector quantization). It combines subband coding, vector quantization and adaptive prediction. The speech signal is split into 16 subbands by means of a QMF filter bank and so every subband is 500 Hz wide. This APVQ encoder can be seen as a vectorial extension of a conventional ADPCM encoder. In this scheme, signal vector is formed with one sample of the normalized prediction error signal coming from different subbands and then it is vector quantized. The prediction error signal is normalized by its gain and normalized prediction error signal is the input of the VQ and therefore an adaptive gain-shape VQ is considered. This APVQ encoder combines the advantages of scalar prediction and those of vector quantization. They evaluate wideband speech coding in the range from 1.5 to 2 bits/sample, that leads to a coding rate from 24 to 32 kbps.Peer ReviewedPostprint (published version

Topics: Àrees temàtiques de la UPC::Enginyeria de la telecomunicació, Àrees temàtiques de la UPC::Enginyeria de la telecomunicació::Processament del senyal::Processament de la parla i del senyal acústic, Speech processing systems, Errors, Adaptive codes, Differential pulse code modulation, Errors, Speech coding, Processament de la parla, Errors
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Year: 1996
DOI identifier: 10.1109/ICSLP.1996.607757
OAI identifier: oai:upcommons.upc.edu:2117/88540
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