Excitation vector generator, speech coder and speech decoder

Abstract

Disclosed are a excitation vector generator and a speech encoding and decoding device. A random code vector reading section and a random codebook of a conventional CELP type speech coder / decoder are respectively replaced with an oscillator for outputting different vector streams in accordance with values of input seeds, and a seed storage section for storing a plurality of seeds. This makes it unnecessary to store fixed vectors as they are in a fixed codebook (ROM), thereby considerably reducing the memory capacity.

Description

[0001] This application is a divisional application of the parent application with the title of "Sound source vector generation device and sound decoding device for sound coding device", the filing date is November 6, 1997, and the application number is 03160355.6. technical field [0002] The present invention relates to a sound source vector generating device capable of obtaining high-quality synthesized sound, and a sound encoding device and a sound decoding device capable of encoding / decoding high-quality sound signals at a low bit rate. Background technique [0003] CELP (Code Excited Linear Prediction: Code Excited Linear Prediction)-type sound coding device performs linear prediction on each frame of sound divided by a certain time, and uses an adaptive codebook that stores past driving sound sources and stores multiple The noise codebook of the noise vector, the way to encode the prediction residual (excitation signal) of the linear prediction of each frame. For exam...

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Problems solved by technology

[0044] However, in the CELP-type speech encoding device / sound decoding device including the above-mentioned algebraic structure sound source in the random codebook, because the object for searching the random codebook is encoded with the burst vector continuously, it is difficult to improve the sound quality. has its limits in terms of improvement

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