JPH0659683A - Noise controller - Google Patents

Abstract

PURPOSE:To simplify the configuration consisting of a plurality of sensors, actuators, and adaptive filters in a noise controller which is used to cancel a noise from an engine, a motor, etc. CONSTITUTION:A noise controller is provided with a plurality of microphones 41 to 43, which detect a residual noise in order to outputs it to a plurality of adaptive filters 11, 12 as an error signal, a plurality of actuators 31, 32, which reproduce the compensating signal from the plurality of filters 11, 12, which cancel the noise, and which form the residual noise, and a plurality of error signal mixing means 51, 52, which mix the error signal from the microphone of each group, when the microphones 41 to 43 are grouped into a plurality of groups, in order to form the mixed error signal and to output each mixed error signal to each adaptive filter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a noise control device for eliminating noise by outputting a signal of noise of an engine, a motor, etc. and an anti-phase equal sound pressure from a speaker, and more particularly to a noise control device of the present invention. An object is to simplify the configuration including the signal processing device.

[0002]

2. Description of the Related Art Conventionally, a passive muffler such as a muffler has been used to reduce noise generated from an internal combustion engine, etc., but improvements have been made in terms of size, muffling characteristics and the like. On the other hand, the noise generated from the sound source and the opposite phase
An active noise control device has been proposed which outputs a compensation sound of equal sound pressure from a speaker to cancel noise. By the way, the frequency characteristic or stability of the active noise control device itself is not sufficient, and its practical application has been delayed. However, as a result of the recent development of signal processing technology for processing digital signals and expansion of the frequency range to be handled, many practical noise control devices have been proposed (for example, Japanese Patent Laid-Open No. 63-311396). An outline of an apparatus for processing digital signals will be described below.

FIG. 7 is a diagram showing an apparatus for processing a digital signal in a conventional noise control apparatus. The digital signal processing device 10 shown in the figure is a DSP (Digital Signal).
Processor), which inputs a reference signal and automatically adjusts the filter coefficient to form a compensation signal (ADF output) that cancels noise, and FIR (Finite Impulse Respo
An nse) type adaptive filter 1 and a coefficient updating unit 2 for updating the filter coefficient of the adaptive filter 1. Here, the reference signal is, for example, a rotation speed signal of an engine as a noise source, a motor, or the like. The signal from the adaptive filter 1 causes the actuator 3 to reproduce the noise of opposite phase and equal sound pressure. Coefficient updating means 2
Forms the filter coefficient so that the error signal, which is the residual sound of the noise detected by the microphone 4 installed near the actuator 2, is minimized.

[0004]

By the way, the conventional digital signal processing device of the noise control device requires one digital signal processing device 10 corresponding to one actuator 3 and one microphone 4. In order to eliminate noise at different places with respect to a common noise source, a noise control device must be provided for each because the transfer characteristics from the noise source to that place are different. Therefore, when the numbers of the actuators 3 and the microphones 4 increase, the number of the digital signal processing devices 10 also increases in response to the increase, so that the scale of the digital signal processing device becomes large and there is a problem in cost.

Therefore, in view of the above problems, it is an object of the present invention to provide a noise control device which can be downsized even when the number of microphones and the like is increased.

[0006]

In order to solve the above problems, the present invention inputs a reference signal to form a compensating signal of an equal phase anti-phase with noise, and eliminates the error signal of the residual sound from which noise is eliminated. A noise control device having an adaptive filter to be minimized is provided with a plurality of microphones, a plurality of actuators and a plurality of error signal mixing means.

The plurality of microphones detect the residual sound and output it to the plurality of adaptive filters as an error signal. The plurality of actuators reproduce the compensation signal from the plurality of adaptive filters to cancel noise and form the residual sound. The plurality of error signal mixing means divides the plurality of microphones into a plurality of groups,
The error signals from the microphones of each group are mixed to form a mixed error signal, and each mixed error signal is output to each adaptive filter.

The error signal mixing means may mix all the error signals from the plurality of microphones and output them to one of the plurality of adaptive filters. The error signal mixing means may mix the error signals from the microphones of each group in common to form a mixed error signal.

Further, a noise control device detects the residual sound and outputs a microphone as an error signal to the plurality of adaptive filters, and reproduces the compensation signals from the plurality of adaptive filters to eliminate noise. There may be provided a plurality of actuators that form the residual sound, and error signal distribution means that outputs a distribution error signal obtained by distributing an error signal from the microphone into a plurality of signals to the plurality of adaptive filters.

Further, in the noise control device, a microphone for detecting the residual sound and outputting it as an error signal to the adaptive filter, and a distribution compensation signal obtained by distributing the compensation signals from the plurality of adaptive filters into a plurality of signals. May be provided to the plurality of actuators, and a plurality of actuators that reproduce the distribution compensation signal from the compensation signal distributor to cancel noise to form the residual sound.

Further, in the noise control device, the plurality of microphones for detecting the residual sound and outputting to the plurality of adaptive filters as error signals and the adaptive filters are divided into a plurality of groups, and the adaptive type of each group is divided into groups. Compensation signal mixing means for mixing the compensation signals from the filter to form a mixed compensation signal, and a plurality of actuators for reproducing the mixed compensation signal from the compensation signal mixing means to eliminate noise and form the residual sound are provided. Good.

The compensating signal mixing means may mix the compensating signals from the adaptive filters of each group in common to form a mixed compensating signal. Further, the compensation signal mixing means may mix all the compensation signals from the plurality of adaptive filters and output them to one of the plurality of actuators.

[0013]

According to the noise control device of the present invention, the residual sound is detected by the plurality of microphones and output as an error signal to the plurality of adaptive filters. The compensation signals from the adaptive filters are reproduced by the actuators to cancel noise and form the residual sound. The plurality of microphones are divided into a plurality of groups by the plurality of error signal mixing means, the error signals from the microphones of each group are mixed to form a mix error signal, and each mix error signal is generated by each of the adaptive filters. Is output to. Therefore, it is not necessary to form the compensation signal for each error signal of the plurality of microphones, and the number of adaptive filters can be reduced with respect to the number of microphones.

Since the error signal mixing means mixes all the error signals from the plurality of microphones and outputs the mixed signal to one of the plurality of adaptive filters, the number of the adaptive filters can be further reduced. . Since the error signal mixing means partially mixes the error signals from the microphones of each group to form a mixed error signal, it is possible to improve the noise effect and reduce the number of adaptive filters.

Since the error signal distribution means distributes the error signal from the microphone into a plurality of signals and outputs the distributed error signal to the plurality of adaptive filters,
Conventionally, a microphone is not required for each of the plurality of adaptive filters, and the number of microphones can be significantly reduced. Since the compensation signals from the plurality of adaptive filters are distributed to the plurality of signals by the plurality of compensation signal distribution means and the distribution compensation signals are output to the plurality of actuators, the adaptive filter is provided for each of the plurality of actuators. It is not necessary and the number of adaptive filters can be greatly reduced.

The adaptive filter is divided into a plurality of groups by the compensation signal mixing means, and the compensation signals from the adaptive filters for each group are mixed to form a mixed compensation signal. An actuator is not required for each filter, and the number of actuators can be reduced. The compensating signal mixing means forms a mixed compensating signal by partially mixing the compensating signals from the adaptive filters of each group to form a mixed compensating signal, so that it is possible to reduce the number of actuators while enhancing the noise effect.

Since the compensation signal mixing means mixes all the compensation signals from the plurality of adaptive filters and outputs the mixed signals to one of the plurality of actuators, the number of actuators can be significantly reduced.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a noise control device according to a first embodiment of the present invention. The noise control device shown in this figure is composed of an FIR type filter that inputs a common reference signal and automatically adjusts filter coefficients to form a compensation signal (ADF outputs 1 and 2) that cancels noise. First and second coefficient updating means 21 for forming the filter coefficients of the adaptive filters 11 and 12 and the first and second adaptive filters 11 and 12 by the method of least squares and supplying them.
And 22, and the first and second for reproducing the mute of the opposite phase equal sound pressure by inputting the compensation signals from the adaptive filters 11 and 12.
Of the actuators 31 and 32, and the first and second actuators 31 and 32, which are installed at different places for detecting the residual sound of the noise formed by the reproduced sound and the noise from the first and second actuators 31 and 32, The error signals as analog signals from the second and third microphones 41, 42 and 43 and the first and second and microphones 41 and 42 are converted into analog signals from the second and third microphones 42 and 43. The error signals are respectively mixed (error inputs 1 and 2), and first and second coefficient updating means 2
1 and 22 for outputting to the first and second error signal mixing means 51 and 52. The adaptive filter 11 and the coefficient updating means 21 are the first digital signal processing device 10-1.
In addition, the adaptive filter 12 and the coefficient updating means 22 form a second digital signal processing device 10-2, and the first digital signal processing device 10-1 and the second digital signal processing device 10-2. Constitutes the digital signal processor 10. The adaptive filter and the coefficient updating means are collectively referred to as an adaptive filter.

Here, the relationship between the microphone and the actuator will be described. FIG. 2 is a diagram showing an example of detecting an error signal based on the positional relationship between the actuator and the microphone in FIG. In this example, three microphones are provided to minimize the error signal. The actuator is basically provided corresponding to the microphone, but if the error signal of the microphone is formed by another actuator, the actuator for that microphone can be omitted. That is, as shown in FIG.
The noise at the position of the microphone 41 is deleted. Second
The actuator 32 of the third microphone 4
The noise at position 3 is eliminated. The noise at the position of the second microphone 42, which was conventionally canceled by the actuator indicated by the virtual line, is silenced by the first and second actuators. In such a mode, since the second microphone detects an error between the noise and the muffling from the first and second actuators, a dedicated actuator for the position of the second microphone 42 becomes unnecessary. Therefore, the number of digital signal processing devices for forming the compensation signals for the actuators is accordingly reduced to two.

However, it is necessary to process the signals from the three microphones with two digital signal processing devices,
In this case, it is particularly necessary to consider the signal processing of the second microphone 42. Returning to FIG. 1, the error signal resulting from the signal from the second microphone is fed back to the first and second coefficient updating means 21 and 22 by the first and second error signal mixing means 51 and 52, and then the second microphone. A filter coefficient is formed in consideration of the error signal of 42, and the compensation signal from the first and second adaptive filters 11 and 12 using this filter coefficient is reproduced by the first and second actuators 31 and 32. The error signal at the position of the second microphone 42 is also optimized.

Here, the first and second mixing means 51 and 52 may be constituted by ordinary adders, and further, the weights between the error signals of the first and second microphones 41 and 42, the second and third weights. The weights between the error signals of the microphones 42 and 43 may be adjusted. Therefore, by allocating the error signal detected by the second microphone 42 to the error signals detected by the other first and third microphones, a digital signal processing device comprising a set of adaptive filters and coefficient updating means. In addition, it is possible to reduce the number of actuators.

The above is the case where there are three microphones for detecting the error signal, but the reduction of the digital signal processing device in the case where there are a plurality of microphones will be described below. FIG. 3 is a diagram showing various modes in which the digital signal processing device can be omitted when there are a plurality of microphones. In the mode 1 shown in the figure, the noise control device includes a plurality of microphones 44-1 and 44-2.
..., 44-n, and of these, a microphone 44-1
And 44-2, microphones 44-3 and 44-4, ...
Error signal mixing means 54-1 for pairing microphones 44- (n-1) and 44-n to mix respective analog signals and output error signals (error inputs 1, 2, ..., M). , 54-2, ..., 54-m. According to this configuration, the number of error signals from the n microphones can be reduced to the number of m error signals (m≈n / 2) in which the error signals from the paired microphones of the same actuator are mixed. In accordance with this reduction, the number of digital signal processing devices can be reduced. In the above, the case where the microphones are paired has been described, but the microphones may be a plurality of groups.

In the mode 2 shown in the figure, the noise control device has a plurality of microphones 45-1, 45-2,
, 45-n and error signal mixing means 55 for mixing the analog signals of all of these microphones and outputting an error signal (error input 1). In this case, when the error signals from all the microphones are formed by a common actuator, the number (n) of error signals from the microphones is reduced to an error signal formed by one mix. Accordingly, only one digital signal processing device is required.

The mode 3 shown in this figure is a modification of the mode 1, in which error signals from n microphones are divided into a plurality of groups, each group shares error signals of several microphones, and each group shares the error signals. An error signal is formed to reduce the number of error signals. Therefore, the number of digital signal processing devices can be reduced similarly to the above. In the mode 4 shown in the figure, the noise control device divides the error signal (error input 1, 2, ...) Into the microphone 47 and the digital signal processing device which divides the output of the error signal from the microphone 47 into a plurality and processes each. , N) for outputting the error signal distribution means 57. According to this mode, the number of digital signal processing devices is not reduced by the error signal distribution means 57 as described above, but the microphone 47 is common because the error signal distribution means 57 mutes only the number of error signal distributions from the actuators. Since the error signal formed in (1) is detected, the error signal distribution means 57 can reduce the number of microphones needed n to one.

The above is the description of reducing the number of digital signal processing devices that simply form a compensation signal from error signals of a plurality of microphones. A noise control device capable of outputting will be described. FIG. 4 is a diagram showing a noise control device according to a second embodiment of the present invention. As described above, the noise control device shown in this figure is a FIR type in which a common reference signal is input and a filter coefficient is automatically adjusted in order to form a compensation signal (ADF outputs 1 and 2) for canceling noise. Adaptive filters 11 and 12 formed of filters, and first and second coefficient updating for forming and supplying filter coefficients of the first and second adaptive filters 11 and 12 by the least square method Means 21 and 22
And the first and second actuators 81 and 83 for inputting the compensation signals (ADF outputs 1 and 2) from the adaptive filters 11 and 12 to reproduce the silence of the anti-phase equal sound pressure, and the first and second actuators 81 and 83. Compensation signal (AD
Compensation signal mixing means 71 for respectively inputting and mixing F outputs 1 and 2), and the compensation signal mixing means 71
A third actuator 82 for forming a silencing signal of opposite phase equal sound pressure from the mixed compensation signal from
The first and second microphones 91 for detecting the error signal, which is the residual sound of the reproduced sound of the actuators 81, 82, and 83 and the noise, and outputting the error signal to the first and second coefficient updating means 21 and 22, And 92.

Here, the microphone 91 has an error signal formed by the first and third actuators 81 and 83, and the microphone 92 has an error signal formed by the second and third actuators 83 and 82. Good. As described above, providing the actuators in a number larger than the number of microphones for detecting the error signal of the residual sound is useful for outputting the reproduced sound from various angles and enhancing the effect of noise control.

According to the present embodiment, the compensation signals to be reproduced by the plurality of actuators are conventionally supplied from the digital signal processing device, but the third actuator 82 is compensated by the compensation signal mixing means 71. Since the signal is supplied, the number of digital signal processing devices is reduced by one. The third actuator 82 forms a compensation signal that minimizes the error signal intermediate the error signals detected by the microphones 91 and 92.

In order to adjust the processing system of the compensation signals from the first and second adaptive filters 11 and 12 before the input of the compensation signal mixing means 71, the signals are inverted or delayed. , Processing system adjusting means 1 for level adjustment
01 and 102 may be provided. Although the number of actuators is three in the above, the scale reduction of the digital signal processing device in the case of a plurality of actuators will be described below.

FIG. 5 is a diagram showing various modes in which the scale of the digital signal processing device can be reduced when there are a plurality of actuators (No. 1). In mode 1 shown in this figure,
The noise control device receives a compensation signal (ADF output) from one digital signal processing device and distributes it to a plurality (n) of signals, and a compensation signal distribution device 72.
, 84-n for inputting the signal from the above and reproducing the compensation signal.

According to the compensating signal distributing means 72, since a plurality of actuator signals are formed by one digital signal processing device, conventionally, a plurality of digital signal processing devices corresponding to a plurality of actuators are required. By comparison, the number of digital signal processing devices can be significantly reduced. Next, the reduction of the number of actuators will be described. Although it is desirable that the number of microphones and the number of digital signal processing devices that detect the error signal be large, the number of actuators may be smaller than the above number. A noise control device capable of reducing the number of actuators in this case will be described.

In mode 2 shown in the figure, the noise control device divides the compensation signals (ADF outputs 1, 2, ..., N) from the digital signal processing device composed of a plurality of adaptive filters into a plurality of groups. , 73-m (n) for compensating signal mixing means 73-1, 73-2, ..., 73-m for mixing the compensating signals from the digital signal processing devices in each group.
> M) and the compensation signal mixing means 73-1 and 73-
, ..., 73-m, and actuators 84-1, 84-2 ,. Each of the actuators 84-1, 84-2, ...
The reproduced sound from 84-m is muted as noise to form a residual sound for a plurality of microphones (not shown).

Main compensation signal mixing means 73-1 and 73-
According to 2, ..., 73-m, it is possible to reduce the number of actuators to m, as compared with the conventional case where n actuators are required corresponding to n digital signal processing devices. Become. Each compensation signal mixing means 7
The processing system adjusting means shown in FIG. 4 may be provided before the input of 3-1, 73-2, ..., 73-m. The same applies hereinafter.

FIG. 6 is a diagram showing various modes in which the scale of the digital signal processing device can be reduced when there are a plurality of actuators (part 2). Compensation signal mixing means 74-1, 74-2, ..., 74-m for mode 3 shown in this figure
In the mode 2, the compensation signals from the digital signal processing devices divided into a plurality of groups are partially commonly input. In this way, the effect of noise control can be improved while reducing the number of actuators.

In the mode shown in this figure, the noise control device has n
Compensation signal mixing means 75 for mixing all the compensation signals (ADF outputs 1, 2, ..., N) from each digital signal processing device, and the mixed compensation signals from the compensation signal mixing means 75 are silently reproduced. Actuator 87
Including and According to the present compensation signal mixing means 75, the number of actuators can be reduced to one as compared with the conventional case where n actuators are required as described above.

In the above description, the reduction of the digital signal processing device and the reduction of the adaptive filter are synonymous.

[0036]

As described above, according to the present invention, the error signal from the microphone is mixed and the compensation signal from the adaptive filter is mixed, so that the number of microphones, adaptive filters, and actuators is increased. Since the system can be reduced, the system can be simplified, miniaturized, and low cost.

[Brief description of drawings]

FIG. 1 is a diagram showing a noise control device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an example of detecting an error signal based on a positional relationship between an actuator and a microphone in FIG.

FIG. 3 is a diagram showing various modes in which the digital signal processing device can be omitted when there are a plurality of microphones.

FIG. 4 is a diagram showing a noise control device according to a second embodiment of the present invention.

FIG. 5 is a diagram showing various modes in which the scale of the digital signal processing device can be reduced when there are a plurality of actuators (No. 1).

FIG. 6 is a diagram showing various modes in which the scale of the digital signal processing device can be reduced when there are a plurality of actuators (No. 2).

FIG. 7 is a diagram showing an apparatus for processing a digital signal in a conventional noise control apparatus.

[Explanation of symbols]

 1 ... Adaptive filter 2 ... Coefficient updating means 3 ... Actuator 4 ... Microphone

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuhiro Sakiyama 1-2-2 Goshodori, Hyogo-ku, Kobe, Hyogo Prefecture Inside Fujitsu Ten Limited

Claims (8)

[Claims] 1. A noise control device having an adaptive filter for inputting a reference signal to form a compensating signal of anti-phase equal sound pressure to noise and minimizing an error signal of a residual sound from which noise is eliminated. A plurality of microphones that detect the noise and output as error signals to the plurality of adaptive filters; and a plurality of actuators that reproduce the compensation signals from the plurality of adaptive filters to eliminate noise and form the residual sound. , A plurality of error signal mix that divides the plurality of microphones into a plurality of groups, mixes error signals from the microphones of each group to form a mix error signal, and outputs each mix error signal to each of the adaptive filters. And a noise control device. 2. The noise control device according to claim 1, wherein the error signal mixing means mixes all error signals from the plurality of microphones and outputs the mixed error signals to one of the plurality of adaptive filters. 3. The noise control device according to claim 1, wherein the error signal mixing means mixes error signals from the microphones of each group in common to form a mixed error signal. 4. A noise control device having an adaptive filter for inputting a reference signal to form a compensating signal of anti-phase equal-sound pressure to noise and minimizing an error signal of residual noise from which noise is eliminated, A microphone that detects and outputs the error signal to the plurality of adaptive filters as an error signal; a plurality of actuators that reproduce the compensation signal from the plurality of adaptive filters to eliminate noise to form the residual sound; A noise control device comprising: an error signal distribution unit that outputs a distribution error signal obtained by distributing an error signal from a microphone into a plurality of signals to the plurality of adaptive filters. 5. A noise control device having an adaptive filter for inputting a reference signal to form a compensation sound signal having an anti-phase equal sound pressure to noise and minimizing an error signal of a residual sound from which noise is eliminated, A microphone that detects sound and outputs the error signal to the adaptive filter as an error signal, and a plurality of compensations that outputs a distribution compensation signal obtained by dividing the compensation signal from the plurality of adaptive filters into a plurality of signals to the plurality of actuators. A noise control apparatus comprising: a signal distribution unit; and a plurality of actuators that reproduce the distribution compensation signal from the compensation signal distribution unit to cancel noise and form the residual sound. 6. A noise control device having an adaptive filter for inputting a reference signal, forming a compensating sound signal having an anti-phase equal sound pressure to noise, and minimizing an error signal of a residual sound from which noise is eliminated. A plurality of microphones that detect sound and output as an error signal to the plurality of adaptive filters, and the adaptive filters are divided into a plurality of groups, and the compensation signals from the adaptive filters of each group are mixed to perform mix compensation. A noise control device comprising: a compensating signal mix means for forming a signal; and a plurality of actuators for reproducing the mix compensating signal from the compensating signal mix means to eliminate noise to form the residual sound. 7. The noise control device according to claim 6, wherein the compensation signal mixing means mixes the compensation signals from the adaptive filters of each group in common to form a mixed compensation signal. 8. The noise control device according to claim 7, wherein the compensation signal mixing means mixes all the compensation signals from the plurality of adaptive filters and outputs the mixed signals to one of the plurality of actuators.