Method and apparatus for enhancing loudness of a speech signal
AssigneeMotorola, Inc.
InventorsMarc Boillot, John Harris
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Abstract
A speech filter (108) enhances the loudness of a speech signal by expanding the formant regions of the speech signal beyond a natural bandwidth of the formant regions. The energy level of the speech signal is maintained so that the filtered speech signal contains the same energy as the pre-filtered signal. By expanding the formant regions of the speech signal on a critical band scale corresponding to human hearing, the listener of the speech signal perceives it to be louder even though the signal contains the same energy.
Claims13
A method of increasing the perceived loudness of a processed speech signal, the processed speech signal corresponding to a natural speech signal and having formant regions and non-formant regions and a natural energy level, the method comprising:
- expanding the formant regions of the processed speech signal beyond a natural bandwidth;
- and
- restoring an energy level of the processed speech signal to the natural energy level.
A speech filter, comprising,
- an analysis portion having a set of filter coefficients determined by warped linear prediction analysis including pole displacement, the analysis portion having unit delay elements;
- a synthesis portion having a set of filter coefficients determined by warped linear prediction synthesis including pole displacement, the synthesis portion having unit delay elements;
- and
- a locally recurrent feedback element having a scaling value coupled to the unit delay elements of the analysis and synthesis portions thereby producing non-linear frequency resolution.
A method of processing a speech signal comprising expanding formant regions of the speech signal on a critical band scale using a warped pole displacement filter.
Dependencies are inferred from the claim text.