Patent ID: 8260611

Claim:
A method of generating a highband excitation signal via an audio coder, wherein the audio coder comprises at least one of an audio encoder, an audio decoder, and an audio codec, said method comprising: harmonically extending via the audio coder at least a magnitude spectrum of a signal that is based on a narrowband excitation signal; calculating via the audio coder a time-domain envelope of a signal that is based on the narrowband excitation signal; modulating via the audio coder a noise signal according to the time-domain envelope; and calculating via the audio coder a weighted sum of (A) a harmonically extended signal based on a result of said harmonically extending and (B) a modulated noise signal based on a result of said modulating, wherein the narrowband excitation signal is based on a residual of a speech signal, and wherein said calculating a weighted sum includes weighting the harmonically extended signal according to a first weighting factor whose value varies over time and weighting the modulated noise signal according to a second weighting factor whose value varies over time, and wherein said calculating a weighted sum includes calculating a value for one among the first and second weighting factors based on at least one of (A) a value of the other among the first and second weighting factors and (B) a desired value of a sum of squared values of the first and second weighting factors, and wherein the highband excitation signal is based on the weighted sum.