IMPROVEMENTS IN SPECTRUM BAND PERCEPTIVE DUPLICATING CHARACTERISTIC AND ASSOCIATED METHODS FOR CODING HIGH-FREQUENCY RECOVERY BY ADAPTIVE ADDITION OF MINIMAL NOISE LEVEL AND LIMITING NOISE SUBSTITUTION Russian patent published in 2004 - IPC

FIELD: coding and decoding systems. SUBSTANCE: proposed method for improving source signal coding system includes following steps: evaluation of minimal source-signal noise level that functions as measure of difference between spectral envelope found by points of local minima of source signal spectral presentation; evaluation of other spectral envelope found by points of local maxima of source-signal spectral presentation; multiplexing of coded signal and minimal noise level to produce output signal of coder. EFFECT: provision for adding and controlling noise levels in the course of their high-frequency recovery in decoder. 16 cl, 9 dwg