Speech coder and speech decoder
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsKazutoshi Yasunaga, Toshiyuki Morii
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Abstract
A dispersed vector generator used in an excitation vector generator for a speech coder/decoder is provided. The dispersed vector generator includes a pulse vector generating section that generates a pulse vector having a signed unit pulse on one element of a vector axis. The dispersed vector generator also includes a dispersion pattern storing section that stores a plurality of dispersion patterns, a switch that selects a dispersion pattern out of the plurality of dispersion patterns stored in the dispersion pattern storing section and a pulse vector dispersion section that generates a dispersed vector by convoluting the selected dispersion pattern and the pulse vector.
Claims12
A method for generating a dispersed vector used for speech decoding, the method comprising:
- providing a pulse vector having a signed unit pulse;
- comparing a value of an adaptive codebook gain with a preset threshold value;
- selecting a dispersion pattern from a plurality of dispersion patterns stored in a memory in accordance with both a result of said comparison and a parameter showing a short-time characteristic of an input speech;
- and
- generating said dispersed vector by convoluting said pulse vector and said selected dispersion pattern.
A dispersed vector generator used for a speech decoder to improve a speech quality, comprising:
- a receiver that receives a code number corresponding to a pulse position and a pulse polarity;
- a pulse vector provider that provides a pulse vector having a signed unit pulse on one element of a vector axis corresponding to said received code number;
- a comparator that compares a value of an adaptive codebook gain with a preset threshold value;
- a selector that selects a dispersion pattern from a plurality of dispersion patterns stored in a memory in accordance with a result of said comparison and a parameter showing a short-time characteristic of an input speech;
- and
- a generator that generates said dispersed vector by convoluting said pulse vector and said selected dispersion pattern.
Dependencies are inferred from the claim text.