Systems and methods for selectively enabling and disabling adaptation of an adaptive noise cancellation system
First Claim
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.
1 Assignment
0 Petitions
Accused Products
Abstract
In accordance with the present disclosure, an adaptive noise cancellation system may include a controller. The controller may be configured to determine a degree of convergence of an adaptive coefficient control block for controlling an adaptive response of the adaptive noise cancellation system. The controller may enable adaptation of the adaptive coefficient control block if the degree of convergence of the adaptive response is below a particular threshold and disable adaptation of the adaptive coefficient control block if the degree of convergence of the adaptive response is above a particular threshold, such that when the adaptive noise cancellation system is adequately converged, the adaptive noise cancellation system may conserve power by disabling one or more of its components.
-
Citations
40 Claims
-
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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
-
-
18. A method for canceling ambient audio sounds in the proximity of a transducer of a personal audio device, the method comprising:
-
receiving an error microphone signal indicative of an acoustic output of the transducer and the ambient audio sounds at the transducer; adaptively generating an anti-noise signal to reduce the presence of the ambient audio sounds by adapting an adaptive response of an adaptive noise cancellation system to minimize the ambient audio sounds at the acoustic output of the transducer, wherein adaptively generating the anti-noise signal comprises; generating the anti-noise signal based on at least the error microphone signal with an anti-noise generating filter; generating a secondary path estimate from a source audio signal with a secondary path estimate filter for modeling an electro-acoustic path of a source audio signal; and at least one of; adaptively generating the anti-noise signal by adapting the response of the anti-noise generating filter to minimize the ambient audio sounds in the error microphone signal, wherein the adaptive response comprises the response of the anti-noise generating filter; and adaptively generating the secondary path estimate by shaping a 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, wherein the adaptive response comprises the response of the secondary path estimate filter; combining the anti-noise signal with a source audio signal to generate an output signal provided to the transducer; determining a degree of convergence of the adaptive response; enabling 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 disabling adaption of the adaptive response for a first period of time and enabling 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. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
-
-
35. A personal audio device comprising:
-
a transducer for reproducing an output signal including both a source audio signal for playback to a listener and an anti-noise signal for countering the effects of ambient audio sounds in an acoustic output of the transducer; an error microphone for generating 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 that generates 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 that generates 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 that shapes 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 that shapes 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; anda 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.
-
-
36. An integrated circuit for implementing at least a portion of a personal audio device, comprising a controller configured to:
-
determine a degree of convergence of an adaptive response of an adaptive filter in an adaptive noise cancellation system; 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, while continuing to apply the adaptive response to generate an anti-noise signal, until the degree of convergence of the adaptive response is below the particular threshold. - View Dependent Claims (37, 38, 39, 40)
-
Specification