SPEECH CODING/DECODING SYSTEM WITH REDUCED QUANTIZATION NOISE

摘要

An input speech signal is encoded by an adaptive quantizer (16) which quantizes the predicted residual signal produced by removing correlations from the digital input signal by predictors (6, 10), wherein a coefficient or weighting factor called a leakage at the predictor (6) is adaptively adjusted by a leakage selector (47) depending upon a prediction gain which indicates the accuracy of the prediction. The value of leakage is in the range between 0 and 1, depending upon the speech signal is voiced sound or unvoiced sound.