Power management of adaptive noise cancellation (ANC) in a personal audio device
First Claim
Patent Images
1. A personal audio device, comprising:
- a personal audio device housing;
a transducer mounted on the housing for reproducing an audio signal including both source audio 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;
at least one microphone mounted on the housing for providing at least one microphone signal indicative of the ambient audio sounds; and
a processing circuit that generates the anti-noise signal using an adaptive filter to reduce the presence of the ambient audio sounds heard by the listener in conformity with the at least one microphone signal, and wherein the processing circuit further estimates a background noise level from the at least one microphone signal and sets a power conservation mode of the personal audio device in conformity with a magnitude of the estimated background noise level, wherein the processing circuit estimates the background noise level from a minimum value of noise sources within a time interval having a predetermined duration using a noise power measurement algorithm that measures the at least one microphone signal using a minima-tracking algorithm over the time interval to filter non-stationary noise sources and non-noise sources from the at least one microphone signal.
1 Assignment
0 Petitions
Accused Products
Abstract
A personal audio device, such as a wireless telephone, includes an adaptive noise canceling (ANC) circuit that adaptively generates an anti-noise signal from an output of a microphone that measures ambient audio. 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 microphone. A processing circuit estimates a level of background noise from the microphone output and sets a power conservation mode of the personal audio device in response to detecting that the background noise level is lower than a predetermined threshold.
-
Citations
27 Claims
-
1. A personal audio device, comprising:
-
a personal audio device housing; a transducer mounted on the housing for reproducing an audio signal including both source audio 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; at least one microphone mounted on the housing for providing at least one microphone signal indicative of the ambient audio sounds; and a processing circuit that generates the anti-noise signal using an adaptive filter to reduce the presence of the ambient audio sounds heard by the listener in conformity with the at least one microphone signal, and wherein the processing circuit further estimates a background noise level from the at least one microphone signal and sets a power conservation mode of the personal audio device in conformity with a magnitude of the estimated background noise level, wherein the processing circuit estimates the background noise level from a minimum value of noise sources within a time interval having a predetermined duration using a noise power measurement algorithm that measures the at least one microphone signal using a minima-tracking algorithm over the time interval to filter non-stationary noise sources and non-noise sources from the at least one microphone signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. A method of countering effects of ambient audio sounds by a personal audio device, the method comprising:
-
adaptively generating an anti-noise signal using an adaptive filter to reduce the presence of the ambient audio sounds heard by the listener in conformity with the at least one microphone signal; combining the anti-noise signal with source audio; providing a result of the combining to a transducer; measuring the ambient audio sounds with at least one microphone; estimating a background noise level from a minimum value of noise sources within a time interval having a predetermined duration by measuring the at least one microphone signal using a minima-tracking algorithm over the time interval to filter non-stationary noise sources and non-noise sources from the at least one microphone signal; and setting a power conservation mode of the personal audio device in conformity with a magnitude of the estimated background noise level. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
-
-
19. 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 both source audio 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; at least one microphone input for receiving at least one microphone signal indicative of the ambient audio sounds; and a processing circuit that adaptively generates the anti-noise signal using an adaptive filter to reduce the presence of the ambient audio sounds heard by the listener in conformity with the at least one microphone signal, and wherein the processing circuit further estimates a background noise level from the at least one microphone signal and sets a power conservation mode of the personal audio device in conformity with a magnitude of the estimated background noise level, wherein the processing circuit estimates the background noise level from a minimum value of noise sources within a time interval having a predetermined duration using a noise power measurement algorithm that measures the at least one microphone signal using a minima-tracking algorithm over the time interval to filter non-stationary noise sources and non-noise sources from the at least one microphone signal. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27)
-
Specification