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ADAPTIVE-NOISE CANCELING (ANC) EFFECTIVENESS ESTIMATION AND CORRECTION IN A PERSONAL AUDIO DEVICE

  • US 20140270223A1
  • Filed: 09/17/2013
  • Published: 09/18/2014
  • Est. Priority Date: 03/13/2013
  • Status: Active Grant
First Claim
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1. A personal audio device, comprising:

  • a personal audio device housing;

    a transducer mounted on the housing for reproducing an audio signal including both source audio for playback to a listener and an anti-noise signal for countering effects of ambient audio sounds in an acoustic output of the transducer;

    a reference microphone mounted on the housing for providing a reference microphone signal indicative of the ambient audio sounds;

    an error microphone mounted on the housing in proximity to the transducer for providing an error microphone signal indicative of the acoustic output of the transducer and the ambient audio sounds at the transducer; and

    a processing circuit that adaptively generates the anti-noise signal from the reference signal by adapting a first adaptive filter to reduce the presence of the ambient audio sounds heard by the listener in conformity with an error signal and the reference microphone signal, wherein the processing circuit implements a secondary path adaptive filter having a secondary path response that shapes the source audio and a combiner that removes the source audio from the error microphone signal to provide the error signal, wherein the processing circuit computes a ratio of a first indication of a magnitude of the error microphone signal including effects of the anti-noise signal to a second indication of the magnitude of the error microphone signal not including the effects of the anti-noise signal to determine an adaptive noise canceling gain.

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