SYSTEMS AND METHODS FOR ADAPTIVE NOISE CANCELLATION BY ADAPTIVELY SHAPING INTERNAL WHITE NOISE TO TRAIN A SECONDARY PATH
First Claim
1. A personal audio device comprising:
- a personal audio device housing;
a transducer coupled to the housing 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 coupled to the housing for providing a reference microphone signal indicative of the ambient audio sounds;
an error microphone coupled to 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 comprising;
an adaptive filter having a response that generates an anti-noise signal from the reference microphone signal, wherein the response is shaped in conformity with the reference microphone signal and a playback corrected error, and wherein the playback corrected error is based on a difference between the error microphone signal and a secondary path estimate;
a secondary path estimate filter configured to model an electro-acoustic path of the source audio signal and have a response that generates the secondary path estimate from the source audio signal;
a secondary coefficient control block that shapes the response of the secondary path estimate filter in conformity with the source audio signal and the playback corrected error by adapting the response of the secondary path estimate filter to minimize the playback corrected error; and
a noise injection portion for injecting a noise signal into the source audio signal, wherein the noise signal is shaped based on the playback corrected error.
2 Assignments
0 Petitions
Accused Products
Abstract
A processing circuit may include: (i) an adaptive filter having a response that generates an anti-noise signal from a reference microphone signal, wherein the response is shaped in conformity with the reference microphone signal and a playback corrected error, and wherein the playback corrected error is based on a difference between an error microphone signal and a secondary path estimate; (ii) a secondary path estimate filter configured to model an electro-acoustic path of a source audio signal and having a response that generates a secondary path estimate from the source audio signal; (iii) a secondary coefficient control block that shapes the response of the secondary path estimate filter in conformity with the source audio signal and the playback corrected error by adapting the response of the secondary path estimate filter to minimize the playback corrected error; and (iv) a noise injection portion for injecting a noise signal into the source audio signal, wherein the noise signal is shaped based on the playback corrected error.
-
Citations
18 Claims
-
1. A personal audio device comprising:
-
a personal audio device housing; a transducer coupled to the housing 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 coupled to the housing for providing a reference microphone signal indicative of the ambient audio sounds; an error microphone coupled to 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 comprising; an adaptive filter having a response that generates an anti-noise signal from the reference microphone signal, wherein the response is shaped in conformity with the reference microphone signal and a playback corrected error, and wherein the playback corrected error is based on a difference between the error microphone signal and a secondary path estimate; a secondary path estimate filter configured to model an electro-acoustic path of the source audio signal and have a response that generates the secondary path estimate from the source audio signal; a secondary coefficient control block that shapes the response of the secondary path estimate filter in conformity with the source audio signal and the playback corrected error by adapting the response of the secondary path estimate filter to minimize the playback corrected error; and a noise injection portion for injecting a noise signal into the source audio signal, wherein the noise signal is shaped based on the playback corrected error. - View Dependent Claims (2, 3, 4, 5, 6)
-
-
7. A method for canceling ambient audio sounds in the proximity of a transducer of a personal audio device, the method comprising:
-
receiving a reference microphone signal indicative of the ambient audio sounds; receiving an error microphone signal indicative of the output of the transducer and the ambient audio sounds at the transducer; generating a source audio signal for playback to a listener; generating an anti-noise signal, from the reference microphone signal, countering the effects of ambient audio sounds at an acoustic output of the transducer by adapting a response of an adaptive filter that filters an output of the reference microphone to minimize the ambient audio sounds in the error microphone signal; adaptively generating a secondary path estimate, from the source audio signal, by filtering the source audio signal with a secondary path estimate adaptive filter configured to model an electro-acoustic path of the source audio signal and adapting the response of the secondary path estimate adaptive filter to minimize a playback corrected error, wherein the playback corrected error is based on a difference between the error microphone signal and the secondary path estimate; injecting a noise signal into the source audio signal, wherein the noise signal is shaped based on the playback corrected error; and combining the anti-noise signal with the source audio signal to generate an audio signal provided to the transducer. - View Dependent Claims (8, 9, 10, 11, 12)
-
-
13. 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 comprising; an adaptive filter having a response that generates an anti-noise signal from the reference microphone signal, wherein the response is shaped in conformity with the reference microphone signal and a playback corrected error, and wherein the playback corrected error is based on a difference between the error microphone signal and a secondary path estimate; a secondary path estimate filter configured to model an electro-acoustic path of the source audio signal and have a response that generates the secondary path estimate from the source audio signal; a secondary coefficient control block that shapes the response of the secondary path estimate filter in conformity with the source audio signal and the playback corrected error by adapting the response of the secondary path estimate filter to minimize the playback corrected error; and a noise injection portion for injecting a noise signal into the source audio signal, wherein the noise signal is shaped based on the playback corrected error. - View Dependent Claims (14, 15, 16, 17, 18)
-
Specification