Patent ID: 8484036

Claim:
A method of signal processing, said method comprising: generating, by a signal processing apparatus, a highband excitation signal based on a narrowband excitation signal, wherein said narrowband excitation signal is based on a result of a first linear prediction analysis operation on a narrowband signal, and wherein said generating a highband excitation signal includes: applying, by the signal processing apparatus, a nonlinear function to a signal that is based on the narrowband excitation signal to generate a spectrally extended signal; performing, by the signal processing apparatus, a second linear prediction analysis operation on the spectrally extended signal to generate a plurality of filter coefficients; based on the filter coefficients, performing, by the signal processing apparatus, a filtering operation on the spectrally extended signal to generate a spectrally flattened signal; and mixing, by the signal processing apparatus, a signal that is based on the spectrally flattened signal with a modulated noise signal to generate a mixed signal, wherein the highband excitation signal is based on the mixed signal, and wherein the modulated noise signal is based on a result of modulating a noise signal according to a time-domain envelope of a signal that is based on the spectrally flattened signal.