Auto-calibrating noise canceling headphone
AssigneeHarman International Industries, Incorporated
InventorUlrich Horbach
Life of this patent
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Abstract
A sound system is provided with a headphone that includes a transducer and at least one microphone. The sound system also includes an equalization filter and a loop filter circuit. The equalization filter is adapted to equalize an audio input signal based on at least one predetermined coefficient. The loop filter circuit includes a leaky integrator circuit that is adapted to generate a filtered audio signal based on the equalized audio input signal and a feedback signal indicative of sound received by the at least one microphone, and to provide the filtered audio signal to the transducer.
Claims10
A sound system comprising:
- a headphone including a transducer and at least two microphones disposed over the transducer and adapted to receive sound radiated therefrom;
- an equalization filter adapted to equalize an audio input signal based on at least one predetermined coefficient;
- and
- a loop filter circuit including a leaky integrator circuit adapted to generate a filtered audio signal based on the equalized audio input signal and a feedback signal indicative of sound received by the at least two microphones, and to provide the filtered audio signal to the transducer;
- and
- a switch adapted to switch between a first position, in which the equalization filter is connected to an audio source for receiving a first audio input signal, and a second position, in which the equalization filter is adapted to receive a second audio input signal;
- a controller programmed to:
- control the switch to be arranged in the second position in response to a user command;
- generate the second audio input signal which is indicative of a test signal;
- receive a second feedback signal indicative of a test sound received by the at least two microphones;
- calibrate the headphone by updating the at least one predetermined coefficient of the equalization filter based on the second feedback signal;
- and
- control the switch to be arranged in the first position in response to the at least one predetermined coefficient being updated.
A computer-program product embodied in a non-transitory computer readable medium that is programmed for automatically calibrating an active noise cancellation control system within a headphone, the computer-program product comprising instructions for:
- generating a first audio input signal that is indicative of a test signal;
- filtering the first audio input signal using an equalization filter and a loop filter;
- providing the first filtered audio signal to a transducer of the headphone, wherein the transducer is adapted to radiate a test sound in response to the first filtered audio signal;
- receiving a first feedback signal indicative of a spatial average of the test sound received by at least one microphone of the headphone;
- updating a coefficient of the equalization filter based on the first feedback signal
- receiving a second audio input signal from an audio source;
- equalizing the second audio input signal using the equalization filter;
- generating a second filtered audio signal using the loop filter based on the equalized second audio input signal and a second feedback signal indicative of a spatial average of sound received by the at least one microphone;
- providing the second filtered audio signal to the transducer;
- controlling a switch to be arranged in a second position in which the equalization filter is connected to a controller for receiving the first audio input signal;
- generating the first audio input signal in response to the switch being arranged in the second position;
- updating the coefficient of the equalization filter based on the first feedback signal;
- and
- controlling the switch to be arranged in a first position in which the equalization filter is connected to an audio source for receiving the second audio input signal, in response to the coefficient being updated.
Dependencies are inferred from the claim text.