M-LCELP speech coding at 4kbps with multi-mode and multi-codebook

• OZAWA K.

  Information Technology Research Laboratories, NEC Corporation

• Serizawa Masahiro

  Information Technology Research Laboratories, NEC Corporation

• Miyano Toshiki

  Information Technology Research Laboratories, NEC Corporation

• Nomura Toshiyuki

  Information Technology Research Laboratories, NEC Corporation

• Ikekawa Masao

  Information Technology Research Laboratories, NEC Corporation

• Taumi Shin-ichi

  Information Technology Research Laboratories, NEC Corporation

抄録

This paper presents the M-LCELP (Multi-mode Learned Code Excited LPC) speech coder, which has been developed for the next generation half-rate digital cellular telephone systems. M-LCELP develops the following techniques to achieve high-quality synthetic speech at 4 kb/s with practically reasonable computation and memory requirements: (1) Multi-mode and multi-codebook coding to improve coding efficiency, (2) Pitch lag differential coding with pitch tracking to reduce lag transmission rate, (3) A two-stage joint design regular-pulse codebook with common phase structure in voiced frames, to drastically reduce computation and memory requirements, (4) An efficient vector quantization for LSP parameters, (5) An adaptive MA type comb filter to suppress excitation signal inter-harmonic noise. The MOS subjective test results demonstrate that 4.075 kb/s M-LCELP synthetic speech quality is mostly equivalent to that for a North American full-rate standard VSELP coder. M-LCELP codec requires 18 MOPS computation amount. The codec has been implemented using 2 floating-point dsp chips.

収録刊行物

• IEICE Trans. Commun.

  IEICE Trans. Commun. 77 (9), 1114-1121, 1994

  一般社団法人電子情報通信学会

キーワード

• speech coding
• vector quantization
• speech processing
• dsp
• cellular telephone

詳細情報

• CRID: 1572824502325536384
• NII論文ID: 110003217232
• NII書誌ID: AA10826261
• ISSN: 09168516
• 本文言語コード: en
• データソース種別:
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