Patent ID: 7003454

Claim:
A method of quantizing spectral parameter vectors in a speech coder, wherein a linear predictive filter is used to compute a plurality of spectral parameter coefficients in a frequency domain, and wherein a pluraltiy of predicted spectral parameter values based on previously decoded output values, and a plurality of residual codebook vectors, along with said plurality of spectral parameter coefficients, are used to estimate spectral distortion for selecting an optimal code vector based on the spectral distortion, said method comprising the steps of: obtaining a plurality of quantized spectral parameter coefficients from the respective predicted spectral parameter values and the residual codebook vectors for forming a quantized spectral representation, the representation having a plurality of elements indicative of said plurality of the quantized spectral parameter coefficients; rearranging the quantized spectral parameter coefficients in the frequency domain in an orderly fashion such that the elements in the representation are distributed in an ascending order; and obtaining the spectral distortion from the rearranged quantized spectral parameter coefficients and the respective spectral parameter coefficients.