The processing volume in calculating a weight value for perceptually weighted vector quantization is decreased to speed up the processing or to minimize hardware. To this end, an inverted LPC finds LPC (linear prediction coding) residuals of an input speech signal which are processed with sinusoidal analysis encoding by a sinusoidal analysis encoding unit. The resulting parameters are processed by a vector quantizer with perceptually weighted vector quantization. For this perceptually weighted vector quantization, the weight value is calculated based on results of an orthogonal transform of parameters derived from the impulse response of the transfer function of the weight.
Reduced length infinite impulse response weighting