Transform coding of speech with weighted vector quantization

A new transform coding of speech is proposed which employs a weighted vector quantization scheme. First, the characteristics of the weighted vector quantization are checked. Then based on these considerations, a frequency domain coder is designed for medium-band (4.8-9.6 kbps) speech coding. In this coding scheme, the linear prediction residue is transformed and vector quantized. In order to control the quantization errors in the frequency domain, adaptively weighted matching is employed instead of the conventional adaptive bit allocation. Therefore, the residual signal can be reconstructed by the decoder, even if the spectral envelope parameters are destroyed due to transmission errors. The coded speech is natural and unaffected by background noise and its mean opinion score at 7.2 kbps is comparable to that of 5.5-bit log PCM coded speech.