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Systems and methods for selectively enabling and disabling adaptation of an adaptive noise cancellation system

  • US 10,181,315 B2
  • Filed: 06/13/2014
  • Issued: 01/15/2019
  • Est. Priority Date: 06/13/2014
  • Status: Active Grant
First Claim
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1. An integrated circuit for implementing at least a portion of a personal audio device, comprising:

  • an output for providing an output signal to a transducer including both a source audio signal for playback to a listener and an anti-noise signal for countering the effect of ambient audio sounds in an acoustic output of the transducer;

    an error microphone input for receiving an error microphone signal indicative of the output of the transducer and the ambient audio sounds at the transducer; and

    a processing circuit that implements;

    an anti-noise generating filter having a response configured to generate the anti-noise signal based on the error microphone signal;

    a secondary path estimate filter configured to model an electro-acoustic path of the source audio signal and having a response configured to generate a secondary path estimate from the source audio signal, wherein at least one of the response of the anti-noise generating filter and the response of the secondary path estimate filter is an adaptive response shaped by an adaptive coefficient control block;

    the adaptive coefficient control block comprising at least one of;

    a filter coefficient control block configured to shape the response of the anti-noise generating filter by adapting the response of the anti-noise generating filter to minimize the ambient audio sounds in the error microphone signal; and

    a secondary path estimate coefficient control block configured to shape the response of the secondary path estimate filter in conformity with the source audio signal and a playback corrected error by adapting the response of the secondary path estimate filter to minimize the playback corrected error, wherein the playback corrected error is based on a difference between the error microphone signal and the secondary path estimate; and

    a controller configured to;

    determine a degree of convergence of the adaptive response;

    enable adaptation of the adaptive response if the degree of convergence of the adaptive response is below a particular threshold; and

    if the degree of convergence of the adaptive response is above the particular threshold, repeatedly disable adaption of the adaptive response for a first period of time and enable adaptation of the adaptive response for a second period of time until the degree of convergence of the adaptive response is below the particular threshold.

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