Active noise control device, vehicle, and active noise control method

Patent metadata

Field	Value
Publication number	US-10950216-B2
Application number	US-201916594729-A
Country	US
Kind code	B2
Filing date	Oct 7, 2019
Priority date	Oct 15, 2018
Publication date	Mar 16, 2021
Grant date	Mar 16, 2021

Abstract

An active noise control device includes: a reference signal source that outputs a reference signal having a correlation with noise; a reference signal input unit configured to receive the reference signal output from the reference signal source; a compressor that compresses the reference signal and outputs a compressed signal of the reference signal when an amplitude of the reference signal received by the reference signal input unit is greater than or equal to a threshold; and an adaptive filter unit configured to generate a canceling signal having a phase opposite to a phase of the compressed signal by multiplying the compressed signal using an adaptive filter having a coefficient that is updated successively. The coefficient of the adaptive filter is updated using a step size parameter for determining an amount of updating the coefficient of the adaptive filter based on a change in the amplitude of the reference signal.

First claim

The invention claimed is:

1. An active noise control device, comprising:
a reference signal source that outputs a reference signal having a correlation with noise;
a reference signal input configured to receive the reference signal output from the reference signal source;
a first gain adjuster that multiplies the reference signal received by the reference signal input by m, where m is a positive number, and outputs, to a compressor, the reference signal multiplied by m;
the compressor that compresses an amplitude of the reference signal multiplied by m within a threshold so that clipping of the reference signal multiplied by m is suppressed and outputs a compressed signal of the reference signal multiplied by m when the amplitude of the reference signal multiplied by m is greater than or equal to the threshold;
a second gain adjuster that multiplies the compressed signal output from the compressor by n, where n is a positive number, and outputs, to an adaptive filter, the compressed signal multiplied by n;
the adaptive filter configured to generate a canceling signal having a phase opposite to a phase of the compressed signal multiplied by n, the compressed signal multiplied by n being multiplied using the adaptive filter, the adaptive filter having a coefficient that is updated successively;
a filter coefficient updater that updates the coefficient of the adaptive filter using a step size parameter, the step size parameter determining an amount of updating the coefficient of the adaptive filter based on a change in the amplitude of the reference signal;
a third gain adjuster that multiplies the reference signal that is not yet input to the first gain adjuster by m×n, and outputs, to a μ adjuster, the reference signal multiplied by m×n; and
the μ adjuster that adjusts the step size parameter using the reference signal multiplied by m×n and output from the third gain adjuster.

2. The active noise control device according to claim 1 , wherein
updating the coefficient of the adaptive filter is stopped while the compressor outputs the compressed signal.

3. The active noise control device according to claim 1 , further comprising:
a canceling signal output configured to receive the canceling signal;
an error signal input configured to receive an error signal that corresponds to a residual sound resulting from interference between the noise and a canceling sound for reducing the noise, the canceling sound being generated using the canceling signal output from the canceling signal output; and
a simulated acoustic transfer characteristic filter configured to generate a filtered reference signal obtained by correcting the reference signal using simulated transfer characteristics that simulate acoustic transfer characteristics from the canceling signal output to the error signal input, wherein
the coefficient of the adaptive filter is further updated using the error signal and the filtered reference signal.

4. A vehicle, comprising:
the active noise control device according to claim 1 .

5. The active noise control device according to claim 1 , wherein a waveform of the compressed signal is same as a waveform of the reference signal.

6. The active noise control device according to claim 1 , wherein the compressed signal and the reference signal have a same frequency.

7. The active noise control device according to claim 1 , wherein the compressed signal and the reference signal have a same wavelength.

8. An active noise control method, comprising:
multiplying a reference signal by m, where m is a positive number, the reference signal being output from a reference signal source and having a correlation with noise;
compressing an amplitude of the reference signal multiplied by m within a threshold so that clipping of the reference signal multiplied by m is suppressed, the reference signal multiplied by m having the amplitude greater than or equal to the threshold;
outputting a compressed signal of the reference signal multiplied by m;
multiplying the compressed signal by n, where n is a positive number;
generating a canceling signal having a phase opposite to a phase of the compressed signal multiplied by n by multiplying the compressed signal multiplied by n output in the multiplying using an adaptive filter, the adaptive filter having a coefficient that is updated successively;
updating the coefficient of the adaptive filter using a step size parameter, the step size parameter determining an amount of updating the coefficient of the adaptive filter based on a change in the amplitude of the reference signal;
multiplying the reference signal, that is not yet multiplied by m, by m×n, and
adjusting the step size parameter using the reference signal multiplied by m×n.

9. The active noise control method according to claim 8 , wherein a waveform of the compressed signal is same as a waveform of the reference signal.

10. The active noise control method according to claim 8 , wherein the compressed signal and the reference signal have a same frequency.

11. The active noise control method according to claim 8 , wherein the compressed signal and the reference signal have a same wavelength.

12. An active noise control device, comprising:
a processor; and
a memory including a control program that, when executed by the processor, causes the processor to perform operations, the operations including:
receiving a reference signal output from a reference signal source, the reference signal having a correlation with noise;

multiplying the reference signal by m, where m is a positive number, the reference signal multiplied by m having an amplitude greater than or equal to a threshold;
compressing the amplitude of the reference signal multiplied by m within the threshold so that clipping of the reference signal multiplied by m is suppressed;
outputting a compressed signal of the reference signal multiplied by m;
multiplying the compressed signal by n, where n is a positive number;
generating a canceling signal having a phase opposite to a phase of the compressed signal by multiplying the compressed signal multiplied by n using an adaptive filter, the adaptive filter having a coefficient that is updated successively;
updating the coefficient of the adaptive filter using a step size parameter, the step size parameter determining an amount of updating the coefficient of the adaptive filter based on a change in the amplitude of the reference signal;
multiplying the reference signal, that is not yet multiplied by m, by m×n; and
adjusting the step size parameter using the reference signal multiplied by m×n.

13. The active noise control device according to claim 12 , the operations further including:
stopping the updating of the coefficient of the adaptive filter while the compressed signal is output.

14. The active noise control device according to claim 12 , the operations further including:
receiving an error signal that corresponds to a residual sound resulting from interference between the noise and a canceling sound for reducing the noise, the canceling sound being generated using the canceling signal; and
generating a filtered reference signal obtained by correcting the reference signal using simulated transfer characteristics that simulate acoustic transfer characteristics from the canceling signal, wherein
the coefficient of the adaptive filter is further updated using the error signal and the filtered reference signal.

15. The active noise control device according to claim 12 , wherein a waveform of the compressed signal is same as a waveform of the reference signal.

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Assignees

• Panasonic Ip Man Co Ltd

Inventors

• Tani Mitsuhiro

Classifications

• G10K2210/3044

  Phase shift, e.g. complex envelope processing · CPC title

• G10K2210/3026

  Feedback · CPC title

• G10K2210/1282

  Automobiles · CPC title

• G10K11/17881 Primary

  the reference signal being an acoustic signal, e.g. recorded with a microphone · CPC title

• G10K2210/3027

  Feedforward · CPC title