Patent ID: 7359854

Claim:
A method of producing in a signal decoder, a wide-band acoustic signal (a WB ) based on a narrow-band acoustic signal (a NB ), the spectrum (A WB ) of the wide-band acoustic signal (a WB ) having a larger bandwidth than the spectrum (A NB ) of the narrow-band acoustic signal (a NB ), the method comprising: receiving the narrow-band acoustic signal (a NB ); extracting by a feature extraction unit, at least one essential attribute (z NB (r, c), E NB ) from the narrow-band acoustic signal (a NB ); estimating by a parameter estimation unit, a parameter describing aspects of wide-band frequency components outside the spectrum (A NB ) of the narrow-band acoustic signal (a NB ) based on the at least one essential attribute (z NB (r, c), E NB ); deriving by a confidence level derivation unit, a confidence level which reflects a probability that an estimated parameter value accurately describes a particular wide-band frequency component; allocating by the signal decoder, the estimated parameter value to the particular wide-band frequency component based on the derived confidence level, wherein the estimated parameter value is allocated such that: a relatively high parameter value is allocated to the particular wide-band frequency component if the confidence level indicates a comparatively high degree of certainty that the parameter value accurately describes the particular wide-band frequency component; and a relatively low parameter value is allocated to the particular wide-band frequency component if the confidence level indicates a comparatively low degree of certainty that the parameter value accurately describes the particular wide-band frequency component; and outputting the wide-band acoustic signal (a WB ) to produce an acoustic signal of improved perceived signal quality compared to the narrow-band acoustic signal (a NB ).