Patent ID: 8892448

Claim:
A method of signal processing by electronic circuitry, said method comprising: based on an excitation signal derived from a low-frequency portion of a speech signal, generating a highband excitation signal; according to the highband excitation signal and a plurality of filter parameters derived from a high-frequency portion of the speech signal, synthesizing a highband speech signal; for each of a series of successive time periods, based on a time-domain envelope of the synthesized highband speech signal over said time period, calculating a corresponding one of a first plurality of gain factor values; and for each of the series of successive time periods, calculating a corresponding one of a plurality of smoothed gain factor values, wherein the smoothed gain factor value is based on a sum of (A) the gain factor, as weighted by a first weight, that corresponds to said time period and (B) a smoothed gain factor value, as weighted by a second weight, that corresponds to a time period that begins earlier than said time period, and wherein at least one among the first and second weights is based on at least one among (A) a distance between gain factor values of the first plurality that correspond to adjacent ones of the series of successive time periods and (B) a ratio between gain factor values of the first plurality that correspond to adjacent ones of the series of successive time periods.