Patent ID: 8868432

Claim:
A method for decoding an audio signal having an audio bandwidth extending beyond an audio bandwidth of a CELP excitation signal in an audio decoder including a CELP-based decoder element, the method comprising: obtaining a second excitation signal having an audio bandwidth extending beyond the audio bandwidth of the CELP excitation signal; obtaining a set of signals by filtering the second excitation signal with a set of bandpass filters; scaling the set of signals using a set of energy-based parameters; obtaining a composite output signal by combining the scaled set of signals with a signal based on the audio signal decoded by the CELP-based decoder element; and scaling the set of signals based on energy at an output of the set of bandpass filters in the audio decoder; wherein the energy at the output of the set of bandpass filters in the audio decoder is determined by an energy measurement interval based on a pitch period of the CELP-based decoder element; and wherein the energy measurement interval, given by I e , is related to the pitch period, T, of the CELP-based decoder element and is dependent upon a level of voicing, V, estimated in the decoder by the following equations: I e = { LT ; V ≥ 0.7 S ; V < 0.7 where S is a fixed number of samples that correspond to a speech synthesis interval and L is an up-sampling factor.