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Source audio acoustic leakage detection and management in an adaptive noise canceling system

  • US 9,773,490 B2
  • Filed: 06/09/2015
  • Issued: 09/26/2017
  • Est. Priority Date: 05/10/2012
  • Status: Active Grant
First Claim
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1. A personal audio device, comprising:

  • a personal audio device housing;

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

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

    a processing circuit within the housing that adaptively generates the anti-noise signal by adaptively filtering the reference microphone signal with a first adaptive filter, such that the anti-noise signal causes substantial cancellation of the ambient audio sounds, wherein the processing circuit determines whether or not an amplitude of acoustic leakage of source audio into the reference microphone is substantial with respect to an amplitude of the ambient audio sounds, and in response to determining that the amplitude of acoustic leakage of source audio into the reference microphone is substantial with respect to the amplitude of the ambient audio sounds, takes action to prevent improper generation of the anti-noise signal; and

    an error microphone mounted on the housing that generates an error microphone signal indicative of the acoustic output of the output transducer and the ambient audio sounds at the output transducer, wherein the processing circuit further generates the anti-noise signal in conformity with an error 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, and wherein the taking action comprises sequencing adaptation of the secondary path adaptive filter and the first adaptive filter so that adaptation of the first adaptive filter is initiated only after adaptation of the secondary path adaptive filter is substantially completed, wherein the adaptation of the secondary path adaptive filter is performed while adaptation of the first adaptive filter is halted, and wherein the sequencing of the adaptation is performed in response to the processing circuit determining that the amplitude of acoustic leakage of the source audio into the reference microphone is substantial with respect to the amplitude of the ambient audio sounds.

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