Leakage-modeling adaptive noise canceling for earspeakers
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 an output transducer including an anti-noise signal for countering the effects of ambient audio sounds in an acoustic output of the output transducer and source audio for playback to a listener;
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 acoustic output of the output transducer and the ambient audio sounds at the output transducer; and
a processing circuit that adaptively generates the anti-noise signal from a corrected reference microphone signal and in conformity with the error microphone signal such that the anti-noise signal causes substantial cancellation of the ambient audio sounds, wherein the processing circuit combines the anti-noise signal with a source audio signal to generate the output signal, wherein the processing circuit further models an acoustic leakage path from the output transducer to the reference microphone with an adaptive filter that filters the source audio signal to generate filtered source audio and removes the filtered source audio from the reference microphone signal to generate the corrected reference microphone signal.
2 Assignments
0 Petitions
Accused Products
Abstract
A personal audio device, such as a headphone, includes an adaptive noise canceling (ANC) circuit that adaptively generates an anti-noise signal from a reference microphone signal that measures the ambient audio, and the anti-noise signal is combined with source audio to provide an output for a speaker. The anti-noise signal causes cancellation of ambient audio sounds that appear at the reference microphone. A processing circuit uses the reference microphone to generate the anti-noise signal, which can be generated by an adaptive filter. The processing circuit also models an acoustic leakage path from the transducer to the reference microphone and removes elements of the source audio appearing at the reference microphone signal due to the acoustic output of the speaker. Another adaptive filter can be used to model the acoustic leakage path.
193 Citations
30 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 an output transducer including an anti-noise signal for countering the effects of ambient audio sounds in an acoustic output of the output transducer and source audio for playback to a listener; 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 acoustic output of the output transducer and the ambient audio sounds at the output transducer; and a processing circuit that adaptively generates the anti-noise signal from a corrected reference microphone signal and in conformity with the error microphone signal such that the anti-noise signal causes substantial cancellation of the ambient audio sounds, wherein the processing circuit combines the anti-noise signal with a source audio signal to generate the output signal, wherein the processing circuit further models an acoustic leakage path from the output transducer to the reference microphone with an adaptive filter that filters the source audio signal to generate filtered source audio and removes the filtered source audio from the reference microphone signal to generate the corrected reference microphone signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
-
11. A method of countering effects of ambient audio sounds by a personal audio device, the method comprising:
-
first measuring ambient audio sounds with a reference microphone to produce a reference microphone signal; second measuring an output of the transducer and the ambient audio sounds at the transducer with an error microphone; adaptively generating an anti-noise signal from a corrected reference microphone signal in conformity with a result of the second measuring for countering the effects of ambient audio sounds in an acoustic output of a transducer; providing the anti-noise signal to the transducer; combining the anti-noise signal with a source audio signal to generate the output signal; modeling an acoustic leakage path from the output transducer to the reference microphone with an adaptive filter that filters the source audio signal to generate filtered source audio; and removing the filtered source audio from the reference microphone signal to generate the corrected reference microphone signal. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
-
-
21. A personal audio device, comprising:
-
a personal audio device housing; a transducer mounted on the housing for reproducing an audio signal including an anti-noise signal for countering effects of ambient audio sounds in an acoustic output of the output transducer and source audio for playback to a listener; a reference microphone mounted on the housing for providing a reference microphone signal indicative of the ambient audio sounds; an error microphone mounted on 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 within the housing that adaptively generates the anti-noise signal from a corrected reference microphone signal and in conformity with the error microphone signal such that the anti-noise signal causes substantial cancellation of the ambient audio sounds, wherein the processing circuit combines the anti-noise signal with a source audio signal to generate the output signal, wherein the processing circuit further models an acoustic leakage path from the output transducer to the reference microphone with an adaptive filter that filters the source audio signal to generate filtered source audio and removes the filtered source audio from the reference microphone signal to generate the corrected reference microphone signal. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30)
-
Specification