Patent ID: 8160889

Claim:
A digital-controller-implemented method for providing increased bandwidth, in a digitally sampled acoustic speech signal having a restricted bandwidth, so as to improve intelligibility of the speech signal, the method comprising: using a digital-controller-implemented spectral shifter, coupled to the speech signal to generate digitally an upper bandwidth extension signal in which at least a portion of the speech signal is shifted upwardly by a predetermined shifting frequency value, and wherein the spectral shifter is configured to perform a cosine modulation of the speech signal; using a first digital-controller-implemented high pass filter, coupled to an output of the spectral shifter, so as to digitally generate a filtered upper bandwidth extension signal by filtering the upper bandwidth extension signal to remove frequency components below a shifter output cutoff frequency; using a second digital-controller-implemented high pass filter, disposed between the speech signal and the spectral shifter, to remove frequency components to the spectral shifter that are below a shifter input cutoff frequency; and generating digitally an extended bandwidth speech signal based on the speech signal and the filtered upper bandwidth extension signal.