Active noise reduction device, mobile object, and active noise reduction method
AssigneePanasonic Automotive Systems Co., Ltd.
InventorShotaro UENO
Life of this patent
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Abstract
An active noise reduction device includes a storage that stores an impulse response with a first sampling rate, the impulse response simulating a sound transfer characteristic ranging from a loudspeaker to a microphone when the adjustment state of a seat is a reference position, and a simulated sound transfer characteristic generator that generates a simulated sound transfer characteristic by acquiring the adjustment state of the seat, shifting the impulse response in a time-base direction according to the acquired adjustment state of the seat, and downsampling the shifted impulse response from the first sampling rate to a second sampling rate.
Claims11
An active noise reduction device that reduces noise at a position of a microphone provided at a seat whose position or orientation is adjustable, by outputting a cancellation sound from a loudspeaker in an inner space of a mobile object, the active noise reduction device comprising:
- a storage that stores an impulse response with a first sampling rate, the impulse response simulating a sound transfer characteristic ranging from the loudspeaker to the microphone when an adjustment state of the seat is a reference position;
- an adaptive filter part that generates a cancellation signal that is used to output the cancellation sound, by applying an adaptive filter to a reference signal that is correlated with the noise and that is output from a reference signal source provided in the mobile object;
- a simulated sound transfer characteristic generator that generates a simulated sound transfer characteristic by acquiring the adjustment state of the seat relative to the position of the microphone, shifting the impulse response in a time-base direction according to the adjustment state of the seat acquired, and downsampling the impulse response shifted, from the first sampling rate to a second sampling rate;
- a simulated sound transfer characteristic filter part that generates a filtered reference signal by correcting the reference signal in accordance with the simulated sound transfer characteristic generated;
- and
- a filter coefficient updater that updates a coefficient of the adaptive filter by using the filtered reference signal generated and an error signal that is output from the microphone and that corresponds to a residual sound caused by interference between the noise and the cancellation sound.
An active noise reduction method that is executed by an active noise reduction device that reduces noise at a position of a microphone provided at a seat whose position or orientation is adjustable, by outputting a cancellation sound from a loudspeaker in an inner space of a mobile object,
- the active noise reduction device including a storage that stores an impulse response with a first sampling rate, the impulse response simulating a sound transfer characteristic ranging from the loudspeaker to the microphone when an adjustment state of the seat is a reference position,
- the active noise reduction method comprising:
- generating a cancellation signal that is used to output the cancellation sound, by applying an adaptive filter to a reference signal that is correlated with the noise and that is output from a reference signal source provided in the mobile object;
- generating a simulated sound transfer characteristic by acquiring the adjustment state of the seat relative to the position of the microphone, shifting the impulse response in a time-base direction according to the adjustment state of the seat, and downsampling the impulse response shifted, from the first sampling rate to a second sampling rate;
- generating a filtered reference signal by correcting the reference signal in accordance with the simulated sound transfer characteristic generated;
- and
- updating a coefficient of the adaptive filter by using the filtered reference signal generated and an error signal that is output from the microphone and that corresponds to a residual sound caused by interference between the noise and the cancellation sound.
Dependencies are inferred from the claim text.