Patent ID: 6275796
Filing Date: 2001-08-14
Classification: G10L

Abstract:
A spectral envelope quantizing apparatus with noise robustness for representing a spectral envelope of speech by a minimum number of bits for the optimal coding of a speech signal, comprising:a line spectrum frequencies (LSFS) input portion for converting linear predictive coding coefficients extracted from the speech into Nth order line spectrum frequencies coefficients and inputting the coefficients as the LSFs of a current frame;a linked split-vector quantizing portion for dividing the LSFs into a predetermined number of linked sub-vectors and quantizing the sub-vectors;a predictive linked split-vector quantizing portion for obtaining the difference between the LSFs of a current frame and the LSFs of a previous frame and vector-quantizing the difference; andan error selector for comparing the error values of the LSFs quantized in the linked split-vector quantizing portion and the predictive linked split-vector quantizing portion, selecting the codebook index of the quantized LSFs having the smaller error value, and outputting the selected codebook index together with a mode bit.