US 9,066,176 B2 · Systems and methods for adaptive noise cancellation including dynamic bias of coefficients of an adaptive noise cancellation system

Abstract

In accordance with method and systems of the present disclosure, a processing circuit may implement an adaptive filter having a response that generates the anti-noise signal from the reference microphone signal to reduce the presence of the ambient audio sounds heard by the listener, a coefficient control block that shapes the response of the adaptive filter in conformity with the error microphone signal and the reference microphone signal by adapting the response of the adaptive filter to minimize the ambient audio sounds in the error microphone signal, and a coefficient bias control block which biases coefficients of the coefficient control block towards zero in a range of frequencies outside of a frequency response of the source audio signal.

Claims39

Dependent claims

A personal audio device comprising:

a transducer for reproducing an audio 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;
a reference microphone for providing a reference microphone signal indicative of the ambient audio sounds;
an error microphone located 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 implements:
an adaptive filter having a response that generates the anti-noise signal from the reference microphone signal to reduce the presence of the ambient audio sounds heard by the listener;
a coefficient control block that shapes the response of the adaptive filter in conformity with the error microphone signal and the reference microphone signal by adapting the response of the adaptive filter to minimize the ambient audio sounds in the error microphone signal;
and
a coefficient bias control block which biases coefficients of the coefficient control block towards zero in a range of frequencies outside of a frequency response of the source audio signal.

6 more elements

A personal audio device comprising:

a transducer for reproducing an audio 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;
a reference microphone for providing a reference microphone signal indicative of the ambient audio sounds;
an error microphone located 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 implements:
a feedforward filter having a response that generates the anti-noise signal from the reference microphone signal to reduce the presence of the ambient audio sounds heard by the listener;
a secondary path estimate adaptive filter configured to model an electro-acoustic path of the source audio signal and have a response that generates a secondary path estimate from the source audio;
a coefficient control block that shapes the response of the secondary path estimate adaptive 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 coefficient bias control block which biases coefficients of the coefficient control block towards zero in a range of frequencies outside of a frequency response of the source audio signal.

7 more elements

An integrated circuit for implementing at least a portion of a personal audio device, comprising:

an output for providing a 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;
a reference microphone input for receiving a reference microphone signal indicative of the ambient audio sounds;
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:
a feedforward filter having a response that generates the anti-noise signal from the reference microphone signal to reduce the presence of the ambient audio sounds heard by the listener;
a secondary path estimate adaptive filter configured to model an electro-acoustic path of the source audio signal and have a response that generates a secondary path estimate from the source audio;
a coefficient control block that shapes the response of the secondary path estimate adaptive 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 coefficient bias control block which biases coefficients of the coefficient control block towards zero in a range of frequencies outside of a frequency response of the source audio signal.

7 more elements

Dependencies are inferred from the claim text.

Systems and methods for adaptive noise cancellation including dynamic bias of coefficients of an adaptive noise cancellation system

Life of this patent

Systems and methods for adaptive noise cancellation including dynamic bias of coefficients of an adaptive noise cancellation system

Life of this patent

Abstract

Claims39