Patent ID: 6611798
Filing Date: 2003-08-26
Classification: G10L,H04B

Abstract:
A method of encoding an acoustic source signal to produce encoded information for transmission over a transmission medium, comprising:producing, in response to the acoustic source signal, a basic coded signal representing perceptually significant characteristics of the acoustic signal; a target signal representing a filtered version of the acoustic source signal; and a primary coded signal representing a reconstructed signal based on the basic coded signal; producing, in response to at least one of the primary coded signal and the target signal a corresponding smoothed signal constituting a perceptually improved representation of the primary coded signal respective the target signal; and producing a secondary coded signal on basis of a combination of either: the smoothed primary coded signal and the target signal; the primary coded signal and the smoothed target signal; or the smoothed primary coded signal and the smoothed target signal, wherein: the primary coded signal comprises coefficients of which each coefficient represents a frequency component; the target signal comprises coefficients of which each coefficient represents a frequency component; and the corresponding smoothed signals are selectively modified versions of the primary coded signal respective the target signal wherein a variation is reduced in the coefficient values representing frequency information above a threshold value.