IEICE Trans - A Fast Encoding Technique for Vector Quantization of LSF Parameters

A Fast Encoding Technique for Vector Quantization of LSF Parameters

Sangwon KANG
Yongwon SHIN
Changyong SON
Thomas R. FISCHER

Publication
IEICE TRANSACTIONS on Communications Vol.E88-B No.9 pp.3750-3755
Publication Date: 2005/09/01
Online ISSN:
DOI: 10.1093/ietcom/e88-b.9.3750
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Multimedia Systems for Communications" Multimedia Systems for Communications
Keyword:
line spectral frequency (LSF), speech coding, split VQ, EVRC, fast search VQ,

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Summary:
A fast encoding technique is described for vector quantization (VQ) of line spectral frequency parameters. A reduction in VQ encoding complexity is achieved by using a preliminary test that reduces the necessary codebook search range. The test is performed based on two criteria. One criterion uses the distance between a specific single element of the input vector and the corresponding element of the codevectors in the codebook. The other criterion makes use of the ordering property of LSF parameters. The fast encoding technique is implemented in the enhanced variable rate codec (EVRC) encoding algorithm. Simulation results show that the average searching range of the codebook can be reduced by 44.50% for the EVRC without degradation of spectral distortion (SD).