Patent ID: 7787640

Claim:
A spectral enhancement system comprising: an input node for receiving an input signal; and a first signal channel for processing the input signal and for providing to an output node a first channel output signal that is within a first channel frequency band, said output node providing an output signal that is spectrally enhanced as compared to the input signal, said first signal channel comprising: a first temporal broad band pass filter coupled to said input node and having a first broad band pass range that is wider than the first channel frequency band of the first signal channel, said temporal first broad band pass filter providing a first broad band pass filtered signal; a first compression circuit coupled to said first temporal broad band pass filter for detecting a first envelope of the input signal within the first broad band pass range, and for non-linearly mapping the first broad band pass filtered signal by a first non-linear factor; a first temporal narrow band pass filter coupled to said first compression circuit and having a first narrow band pass range that is narrower than said first broad band pass range and providing a first narrow band pass filter signal, said first narrow band pass range being the same as the first channel frequency band of the first signal channel; and a first expansion circuit coupled to said temporal first narrow band pass filter for performing an expansion function of said first narrow band pass filtered signal, said expansion circuit includes a first detecting element to detect one or more non-linear factors of the input signal within the first narrow band pass range in said first temporal narrow band pass filter and uses said first non-linear factor and a second non-linear factor to perform said expansion function.