Design of a robust LSP quantizer for a high-quality 4-kbit/s CELP speech coder

Yusuke Hiwasaki*, Kazunori Mano, Kazutoshi Yasunaga, Toshiyuki Morii, Hiroyuki Ehara, Takao Kaneko

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


This paper presents an efficient LSP quantizer implementation for low bit-rate coders. The major feature of the quantizer is that it uses a truncated cepstral distance criterion for the code selection procedure. This approach has generally been considered too computationally costly. We utilized the quantizer with a moving-average predictor, two-stage-split vector quantizer and delayed decision. We have investigated the optimal parameter settings in this case and incorporated the quantizer thus obtained into an ITU-T 4-kbit/s speech coding candidate algorithm with a bit budget of 21 bits. The objective performance is better than that with a conventional weighted mean-square criterion, while the complexity is still kept to a reasonable level. The paper also describes the codebook design and techniques that were employed to achieve robustness in noisy channel conditions.

Original languageEnglish
Pages (from-to)1496-1506
Number of pages11
JournalIEICE Transactions on Information and Systems
Issue number6
Publication statusPublished - 2004 Jun
Externally publishedYes


  • Line spectral frequencies
  • Line spectrum pairs
  • Spectral quantization
  • Speech coding
  • Split vector quantization

ASJC Scopus subject areas

  • Software
  • Hardware and Architecture
  • Computer Vision and Pattern Recognition
  • Electrical and Electronic Engineering
  • Artificial Intelligence


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