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SPEECH DISTRIBUTION SYSTEM

  • US 20080021706A1
  • Filed: 08/06/2007
  • Published: 01/24/2008
  • Est. Priority Date: 12/09/1999
  • Status: Abandoned Application
First Claim
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1. A method of distributing speech in the presence of an audio system and using a single microphone (18.1) which includes the steps of:

  • (a) at a first location receiving a first audio signal (S1a) through a single microphone (18.1), the first audio signal including a second signal related to an output of the audio system, a voice signal representing speech originating from or near the first location, and noise (AS1m), (b) extracting from the first audio signal a third signal (S1ae1), representing the voice signal and the noise, by subtracting from the first audio signal an estimation of the second signal, determined by using an electrical output signal (Ase) of the audio system on its own as a reference signal for an adaptive filter, (52), the third signal being extracted directly from the first audio signal and without going through a loudspeaker and microphone first, (c) amplifying the third signal and then mixing the third signal (S1ae1) with the electrical output signal (Ase) to produce a combined output signal, (d) distributing the combined output signal through the audio system to at least one loudspeaker (12.2 to 12.4), said method further including at least one of the following steps;

    (i) automatically adjusting the level of amplification of the third signal in step (c) based on at least the level of background noise;

    (ii) individually adjusting the level of amplification of the third signal in step (c) for each loudspeaker;

    (iii) reducing the third signal in step (c) if it is determined that no speech is present in the first audio signal (S1a), and (iv) using the combined output(s) as reference input(s) to an adaptive echo cancellation mechanism (54) to reduce acoustic feedback.

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