Patent ID: 7760893

Claim:
For an audio amplifier having a manual volume control, which provides an audio signal to one or more speakers, an automatic volume control to compensate for speech interference noise comprising: a) a microphone for detecting acoustic waves emanating from the one or more speakers and background noise, and in response for producing a corresponding signal; b) a phase correlator process for phase correlating the microphone and amplifier signals; c) an amplitude correlator process for amplitude correlating the phase correlated microphone and amplifier signals; d) a subtraction process for producing a signal corresponding to a difference between the phase and amplitude correlated microphone and amplifier signals; e) a transform process for producing over a period of time a signal corresponding to the amplitude of each frequency component of the difference signal within the spectrum of said transform process; f) a bandpass filter process for filtering the transform process produced signal to pass only those frequency components within selected bands; g) a speech interference noise level calculation process for receiving the bandpass filtered frequency components and responsive to produce a signal corresponding to a combination of the amplitudes of the bandpass filtered frequency components; and h) a solver process for receiving the combined amplitudes of the bandpass filtered frequency components and responsive to produce according to an algorithm a signal for controlling the gain of the audio amplifier; i) a constraint process for receiving input from the manual volume control and responsive to produce according to an algorithm a signal constraining the gain control signal.