LOW-LATENCY MULTI-DRIVER ADAPTIVE NOISE CANCELING (ANC) SYSTEM FOR A PERSONAL AUDIO DEVICE
First Claim
1. A personal audio system, comprising:
- a source of audio for reproduction, wherein the source of audio provides a source audio signal;
a first transducer for reproducing high-frequency content of the source audio signal for playback to a listener and a first anti-noise signal for countering the effects of ambient audio sounds in an acoustic output of the first transducer;
a second transducer for reproducing low-frequency content of the source audio signal for playback to the listener and a second anti-noise signal for countering the effects of ambient audio sounds in an acoustic output of the second transducer;
at least one microphone for providing at least one microphone signal indicative of the ambient audio sounds; and
a processing circuit that generates the first anti-noise signal and the second anti-noise signal from the at least one microphone signal using a first filter to reduce the presence of the ambient audio sounds at the first transducer and the second transducer in conformity with the at least one microphone signal, wherein the processing circuit generates the second anti-noise signal from the at least one microphone signal using a second filter to reduce the presence of the ambient audio sounds at the first transducer and the second transducer in conformity with the at least one microphone signal.
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Accused Products
Abstract
A personal audio device including multiple output transducers for reproducing different frequency bands of a source audio signal, includes an adaptive noise canceling (ANC) circuit that adaptively generates an anti-noise signal for each of the transducers from at least one microphone signal that measures the ambient audio to generate anti-noise signals. The anti-noise signals are generated by separate adaptive filters such that the anti-noise signals cause substantial cancellation of the ambient audio at their corresponding transducers. The use of separate adaptive filters provides low-latency operation, since a crossover is not needed to split the anti-noise into the appropriate frequency bands. The adaptive filters can be implemented or biased to generate anti-noise only in the frequency band corresponding to the particular adaptive filter. The anti-noise signals are combined with source audio of the appropriate frequency band to provide outputs for the corresponding transducers.
55 Citations
30 Claims
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1. A personal audio system, comprising:
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a source of audio for reproduction, wherein the source of audio provides a source audio signal; a first transducer for reproducing high-frequency content of the source audio signal for playback to a listener and a first anti-noise signal for countering the effects of ambient audio sounds in an acoustic output of the first transducer; a second transducer for reproducing low-frequency content of the source audio signal for playback to the listener and a second anti-noise signal for countering the effects of ambient audio sounds in an acoustic output of the second transducer; at least one microphone for providing at least one microphone signal indicative of the ambient audio sounds; and a processing circuit that generates the first anti-noise signal and the second anti-noise signal from the at least one microphone signal using a first filter to reduce the presence of the ambient audio sounds at the first transducer and the second transducer in conformity with the at least one microphone signal, wherein the processing circuit generates the second anti-noise signal from the at least one microphone signal using a second filter to reduce the presence of the ambient audio sounds at the first transducer and the second transducer in conformity with the at least one microphone signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of countering effects of ambient audio sounds by a personal audio system, the method comprising:
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measuring ambient audio sounds with at least one microphone to produce at least one microphone signal; first generating a first anti-noise signal from the at least one microphone signal using a first filter to reduce the presence of the ambient audio sounds at the first transducer in conformity with the at least one microphone signal; second generating a second anti-noise signal from the at least one microphone signal using a second filter to reduce the presence of the ambient audio sounds at the second transducer in conformity with the at least one microphone signal; providing a source of audio for reproduction, wherein the source of audio provides a source audio signal; reproducing high-frequency content of the source audio signal and the first anti-noise signal with the first transducer; and reproducing low-frequency content of the source audio signal and the second anti-noise signal with the second transducer. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. An integrated circuit for implementing at least a portion of a personal audio system, comprising:
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a source of audio for reproduction, wherein the source of audio provides a source audio signal; a first output for providing a first output signal to a first transducer for reproducing high-frequency content of the source audio signal and a first anti-noise signal for countering the effects of ambient audio sounds in an acoustic output of the first transducer; a second output for providing a second output signal to a second transducer for reproducing a second audio signal including both second source audio for playback to a listener and a second anti-noise signal for countering the effects of ambient audio sounds in an acoustic output of the second earspeaker; at least one microphone input for providing at least one microphone signal indicative of the ambient audio sounds; and a processing circuit that generates the first anti-noise signal and the second anti-noise signal from the at least one microphone signal using a first filter to reduce the presence of the ambient audio sounds at the first transducer and the second transducer in conformity with the at least one microphone signal, wherein the processing circuit generates the second anti-noise signal from the at least one microphone signal using a second filter to reduce the presence of the ambient audio sounds at the first transducer and the second transducer in conformity with the at least one microphone signal. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27)
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28. A personal audio system, comprising:
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multiple output transducers; at least one microphone for providing at least one microphone signal indicative of the ambient audio sounds; and a processing circuit that implements adaptive noise-canceling in which multiple adaptive filters generate multiple anti-noise signals for corresponding ones of the multiple output transducers and operate as cross-overs for separating the at least one microphone signal into multiple frequency bands corresponding to the multiple output transducers by generating the multiple anti-noise signals in the corresponding ones of the multiple frequency bands.
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29. A method of countering effects of ambient audio sounds by a personal audio system, the method comprising:
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measuring ambient audio sounds with at least one microphone to generate at least one microphone signal; generating multiple anti-noise signals for providing to corresponding ones of multiple output transducers using corresponding ones of multiple adaptive filters that operate as cross-overs for separating the at least one microphone signal into multiple frequency bands corresponding to the multiple output transducers by generating the multiple anti-noise signals in the corresponding ones of the multiple frequency bands.
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30. An integrated circuit for implementing at least a portion of a personal audio system, comprising:
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multiple outputs for providing multiple output signals to corresponding ones of multiple output transducers; at least one microphone input for receiving at least one microphone signal indicative of the ambient audio sounds; and a processing circuit that implements adaptive noise-canceling in which multiple adaptive filters generate multiple anti-noise signals at corresponding ones of the multiple outputs and operate as cross-overs for separating the at least one microphone signal into multiple frequency bands corresponding to the multiple output transducers by generating the multiple anti-noise signals in the corresponding ones of the multiple frequency bands.
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Specification