JPH06175668A - Noise controller - Google Patents

Abstract

PURPOSE:To efficiently cancel noises in multipoints in a vehicle room by forming cancel sounds with an opposite phase and an equal sound pressure to the noises. CONSTITUTION:A processing part 3 consisting of an adaptive filter for outputting plural compensation signal for multipoints so as to make an error signal due to a remaining sound canceling the noise minimum, an input switch 4 controlling that the error signals from the multipoints are inputted to the processing part 3, an output switch 5 controlling the compensation signal outputted from the processing part 3 to the multipoints and the select 6 of switch, etc., controlling the switches of the input switch 4 and the output switch 5, controlling the processing constitution of the processing part 3 and having a switch, etc., pattern memory 7 previously storing a switch pattern performing such a control, are provided on, the noise controller forming a cancel sound with an opposite phase and an equal sound pressure to the noise in the multipoints in a space in the vehicle room.

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 forming a cancellation sound having a phase opposite to that of noise and equal sound pressure.

[0002]

2. Description of the Related Art Conventionally, as a technique in such a field, there is one disclosed in Japanese Patent Laid-Open No. 63-311396. What is described in this is that noise is detected by a noise source microphone installed upstream of the duct, and a signal processing circuit outputs a signal of opposite phase and equal sound pressure from the speaker installed downstream of the duct and is canceled. A combination of a feedback system that detects and feeds back the result with a canceling microphone and a feedforward system,
This is a so-called 2-microphone / 1-speaker type active noise control device.

In this noise control device, a DSP (Digital Signal Processor) is usually used as a signal processing technique using a digital circuit for processing a digital signal obtained by converting an analog signal at a predetermined sampling frequency. Is an adaptive filter (Adap
The adaptive FIR filter forms a compensation sound for canceling noise having periodicity. As an applied technology, there is one that controls noise at multiple points in the vehicle interior. Below, as an example of this control, 4 sensors that are 4 point control, 4
The speaker and four adaptive filter configurations will be described.

FIG. 10 is a schematic diagram for explaining multipoint noise control in a conventional noise control device. The noise control device shown in the figure includes, for example, speakers s1, s2, s provided for canceling noise at each seat in a vehicle.
3, s4 and microphones M1, M2, M3, M4 for respectively capturing residual sounds generated by superposition of noise and cancellation sound from the speakers s1, s2, s3, s4.
Based on a reference signal, the speakers s1, s2, s3,
Adaptive filters (ADF1, ADF2, ADF3, A that form a compensation sound for outputting a cancellation sound in s4)
DF4) and the microphones M1, M2, M3, M
The coefficient updating unit (LMS1, LMS2, LMS1, LMS2, ADF4, ADF2, ADF3, ADF4, which forms the filter coefficient so as to minimize the error signal of the residual sound captured by
LMS3, LMS4) and the transfer characteristics between the speakers s1, s2, s3, s4 and the microphones M1, M2, M3, M4 based on the reference signal, and the LMS1, LMS2, LMS3, LMS4 form the transfer characteristics. Transfer characteristic forming section (FIR 11, 21,
31, 41, FIR12, 22, 32, 42, FIR1
3,23,33,43, FIR14,24,34,4
4) and in conjunction with FIR 11, 21, 31, 41 and LM
Switch SW1 for switching between S1 and FIR12, 2
Switch SW for switching between 2, 32, 42 and LMS2
2, a switch SW3 for switching between the FIRs 13, 23, 33, 43 and the LMS 3, and FIRs 14, 24, 34,
Switch SW4 for switching between 44 and LMS4, microphones M1, M2, M3, M4 and LMS1, LMS
Switch SW5 for switching between 2, LMS3 and LMS4
Consists of. In this way, the switches SW1, 2, 3, 4,
5 is periodically switched to eliminate noise at multiple points. Here, there are various methods of forming the reference signal, there is a method of forming by synthesizing frequencies of various orders with an engine pulse as a fundamental frequency, and a compensation signal of an adaptive filter and an error signal from a microphone. There is a method in which the engine noise is directly synthesized by a microphone, but the method may be any method in the present invention.

The adaptive filter is a FIR (Finite Impulse Response) filter having a variable multiplication coefficient.

[0006]

However, in the conventional noise control device for multipoint control, all the adaptive filters are always in the ON state, but the noise condition in the vehicle compartment changes depending on the engine speed. In addition, there is a problem in that there is a point where it is not necessary to cancel noise depending on the passengers, and it is difficult to secure a necessary processing amount at a low engine speed. That is, the DSP for processing the digital signal is not used efficiently, and unnecessary processing operations cause instability.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a noise control device capable of performing efficient multipoint control in view of the above problems.

[0008]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a noise control device for forming a canceling sound of opposite phase and equal sound pressure with noise at multiple points in a vehicle interior space, and a processing unit. Input switches, output switches, and switches are selected. The processing unit comprises an adaptive filter for outputting a plurality of compensation signals for the multipoints so as to minimize an error signal due to a residual sound in which the noise is canceled.

The input switch controls the input of the error signal from the multipoint to the processing unit. The output switch controls output of a compensation signal from the processing unit to the multipoint. The selection of the switch or the like controls the switching of the input switch and the output switch, controls the processing configuration of the processing unit, and has a pattern memory of a switch or the like in which a switch pattern for performing such control is stored in advance. is there.

In selecting the SW or the like, the number of revolutions of the engine of the vehicle is detected, and the input switch and the output switch are controlled so as to narrow down the output of the compensation signal to the required multipoints according to the number of revolutions. . For the selection of the SW or the like, the position of the occupant is detected, and the input switch and the output switch are controlled so as to narrow down the output of the compensation signal to the multi-point where the occupant is.

For selecting the SW or the like, the number of revolutions of the engine of the vehicle is detected, and the input switch is controlled so as to synthesize the input to the processing unit as the rotation speed changes from high to low.
In response to this combination, the number of formed compensation signals in the processing unit 3 is reduced, control is performed to increase the filter length of the adaptive filter, and the output switch is controlled to branch and output the compensation signals. There is.

[0012]

According to the noise control device of the present invention, the number of revolutions of the engine of the vehicle is detected in selecting the SW or the like, and the output of the compensation signal is narrowed down to necessary multipoints as the revolution speed is changed from low to high. By controlling the input switch and the output switch to increase the number of multipoints from low rotation speed to high rotation speed, the number of operation systems is reduced, stable operation is achieved, and unnecessary processing systems are
By using FF, the processing amount can be reduced, and since the DSP can be used for other processing during this period, the efficiency is improved and the hardware can be downsized as a whole.

In selecting the SW or the like, the position of the occupant is detected, and the input switch and the output switch are controlled so that the output of the compensation signal is narrowed down to the multipoint where the occupant is located. Since it is changed, it is possible to obtain the same effect as the above. In selecting the SW or the like, the rotation speed of the engine of the vehicle is detected, and the input switch is controlled so that the input to the processing unit is combined as the rotation speed changes from high rotation to low rotation, and the processing unit 3 responds to this combination. Control to reduce the formation of compensation signal and increase the filter length of the adaptive filter,
By controlling the output switch so as to branch and output the compensation signal, the number of processing stages of the processing unit 3 is reduced and the FIR filter length is increased as the rotation speed changes from high rotation to low rotation, so that the accuracy is improved at low rotation. The amount of unnecessary processing can be reduced, which contributes to downsizing of the hardware surface.
Furthermore, the number of operating systems is reduced, and stability can be improved.

[0014]

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 an embodiment of the present invention. The noise control device shown in this figure is a vehicle 100.
Speakers S1, S2, S3, S4 provided near each seat inside for canceling noise at that position, and a microphone M1 for capturing a residual sound whose noise is canceled by the speakers S1, S2, S3, S4. , M2, M
3, M4, a rotation speed detection unit 2 that detects the rotation speed of the engine from the engine pulse from the engine 1, an occupant position sensor 13 that indicates an occupant position in the vehicle, and the speaker S.
1, a processing unit 3 for forming a compensation signal for outputting a cancel sound to S2, S3, S4, and a processing unit 3 provided between the processing unit 3 and the microphones M1, M2, M3, M4. An input switch 4 for controlling an input; an output switch 5 provided between the processing unit 3 and the speakers S1, S2, S3, S4 for controlling an output from the processing unit 3; Based on the signal from the occupant position sensor 13, the selection unit 6 such as a switch that switches the configuration of the processing unit 3, the input switch 4 and the output switch 5, and the processing unit 3 based on the information of the rotation speed detection unit 2 and the occupant position sensor in advance. , A pattern memory 7 such as a switch that stores a pattern for switching the configuration of the input switch 4 and the output switch 5 in advance, and the processing unit 3 processes signals of the microphones M1, M2, M3, and M4. A signal converter 8 for converting into so that,
A signal conversion unit 9 for converting the compensation signal of the processing unit 3 so that it can be output to the speakers S1, S2, S3, and S4.

FIG. 2 is a diagram showing the configuration of the processing unit 3 of FIG. The processing unit 3 shown in the figure has a basic configuration, and SW5 for periodically switching the signal via the input switch 4
And a processing unit 1, 2 for forming a compensation signal based on the signal from the SW 5 and the reference signal and outputting it to the output switch 5, respectively.
3 and 4 are provided. FIG. 3 shows each process 1, 2, 3, 4 of FIG.
It is a figure which shows the structure of. Each processing 1, 2, 3, shown in this figure
The description of the configuration of No. 4 is the same as that of FIG.

FIG. 4 is a diagram showing the configuration of the signal conversion unit 8 for the signal from the microphone. The conversion unit 8 shown in the figure includes amplifiers for amplifying the signals of the microphones M1, M2, M3, and M4, low-pass filters connected to the amplifiers to remove high-frequency components and prevent aliasing, and low-pass filters. A / D converter (Analog to Digital Converter) that converts an analog signal connected to a pass filter to a digital signal
ter).

FIG. 5 is a diagram showing the configuration of the signal conversion unit 9 for the signal to the speaker. The signal conversion unit 9 shown in the figure is a D / A converter (Digital to Analog Converter) for converting each digital signal from the output switch 5 into an analog signal,
A low-pass filter connected to each D / A converter to remove high-frequency components, and a power amplifier connected to each low-pass filter to drive speakers S1, S2, S3, S4 are provided.

Next, the first operation of the select 6 such as a switch
And the examples of 2 will be described. 6 and 7 are diagrams showing first and second examples of the operation by the select 6 such as SW in FIG.
In the processing unit 3 of FIG. 6, SW5 is omitted for the sake of simplification of the description (the same applies hereinafter). In the select 6 such as SW, the rotation speed detection unit 2 first detects the rotation speed and turns on only the speaker and the microphone at a position with a high noise level.
And the rest is turned off. This is because the noise level distribution in the vehicle compartment varies depending on the number of revolutions. The SW or the like pattern memory 7 stores the switch pattern in the case where the difference is measured to determine which seat should be canceled depending on the rotational speed. For example, since the noise level of all seats is high at low rotation speeds, all the processes 1, 2, 3, 4 should be operated in order to cancel noise at all seats as in the low rotation speed shown in FIG. Input switch 4
And the pattern of the output switch 5 is stored so as to be through. However, since the noise level becomes high only in the front seats or the rear seats at the time of high rotation, the switches 4 and 5 are controlled as in the case of high rotation shown in FIG. The switch patterns of the input switch 4 and the output switch 5 are stored so that only the processes 1 and 4 of No. 3 are set to the through mode to operate. Therefore, in the case of high rotation, the processes 2 and 3 need not be operated.
The unnecessary processes 2 and 3 are separated from the processing unit 3 by the select 6 such as SW. Therefore, according to the present embodiment, the number of multi-points is increased as the rotation speed is changed from low rotation speed to high rotation speed, so that the number of operation systems is reduced, stable operation is performed, and the unnecessary processing system is turned off to reduce the processing amount. Can be reduced to DS
Since P can be used, the efficiency is improved and the hardware can be downsized as a whole.

A third example of the operation of the select 6 such as SW will be described. The SW etc. pattern memory 7 stores the occupant position and the switch patterns of the input switch 4 and the output switch 5. The input switch 4 and the output switch 5
The switch pattern is for turning on the microphone and speaker of the seat where the passenger is, and turning off the microphone and speaker of the seat where there is no passenger. In the select 6 such as SW, the occupant position sensor 13 detects the occupant position and controls the switches 4 and 5 to operate the processing of the processing unit 3 only for the seats in which the occupant is present. Then, the processing that is not operating is separated from the processing unit 3. Therefore, according to the present embodiment, since the multipoint is changed depending on the position of the occupant, it is possible to obtain the same effect as the above.

Next, fourth and fifth examples of the operation of the select 6 such as SW will be described. 8 and 9 are diagrams showing fourth and fifth examples of the operation by the select 6 such as SW in FIG. The noise cycle fluctuates depending on the engine speed, but at low rpm the noise cycle is low, so the spatial variation of noise in the passenger compartment is small, but the wavelength of the noise becomes longer, and at high rpm the opposite is true. . In consideration of this feature, the pattern memory 7 for SW or the like processes each of the processes 1, 2,
The patterns of the input switch 4 and the output switch 5 are stored so as to be through in order to connect to the speaker and the microphone so that 3 and 4 operate. Further, at the time of low rotation shown in FIG. 9, the SW etc. pattern memory 7 combines the signals from the signal converter 8 into one input switch 4
The switch pattern is stored. Further, in this case, each processing of the processing unit 3 is collectively FI in the pattern memory 7 such as SW so that the combined signal can be processed.
The switch pattern is stored so as to increase the tap length of the R filter. Further, the SW or the like pattern memory 7 stores the switch pattern of the output switch 5 for branching the signal from the processing section 3 to the respective speakers S1, S2, S3, S4. In this way, switching the switch patterns so as to be stored in the SW or the like pattern memory 7 at high rotation and low rotation is because the period of noise is small at high rotation, and the influence of the spatial distribution of noise becomes large. Since the control requires control and the wavelength of the noise is short, the tap length of the FIR filter may be short for accuracy, but at low rotation, the opposite is true, and the period of the noise is large, which reduces the influence of the spatial distribution of noise. This is because the multi-point control is relatively unnecessary and the wavelength of noise is long, so that the accuracy is better when the tap length of the FIR filter is larger. Thus, according to the present embodiment, the number of processing stages of the processing unit 3 is generally gradually decreased from the high rotation speed to the low rotation speed, and the FIR
Since the filter length is gradually increased, accuracy is improved at low speeds and unnecessary processing volume can be reduced, which contributes to downsizing of the hardware surface and further reduces the operating system and improves stability. .

In the first and second examples and the fourth and fifth examples of the selection 6 of SW or the like, the engine speed is switched in reverse to each other due to the configuration, but either the control of the noise level or the improvement of the accuracy is performed. They are common in that they are used with emphasis on crab and both achieve the same purpose.

[0022]

As described above, according to the present invention, the multipoint is changed according to the rotation, and the multipoint is changed depending on the position of the occupant. The operation becomes stable and the amount of processing can be reduced by turning off the unnecessary processing system. During this period, the DSP can be used for other processing, so that the efficiency is improved and the hardware can be downsized as a whole. Further, as the number of stages in the processing unit is reduced and the filter length of the adaptive filter is increased as the rotation speed is changed from high rotation to low rotation, the accuracy is improved at low rotation.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a configuration of a processing unit 3 in FIG.

FIG. 3 is a diagram showing a configuration of each processing 1, 2, 3, 4 of FIG.

FIG. 4 is a diagram showing a configuration of a signal conversion unit 8 for a signal from a microphone.

FIG. 5 is a diagram showing a configuration of a signal conversion unit 9 for a signal to a speaker.

FIG. 6 is a diagram showing a first example of an operation at a low rotation speed by the select 6 such as SW of FIG.

FIG. 7 is a diagram showing a second example of the operation at the time of high rotation by the select 6 such as SW of FIG.

FIG. 8 is a diagram showing a fourth example of the operation at the time of high rotation by the select 6 such as SW of FIG.

FIG. 9 is a diagram showing a fifth example of the operation at the time of low rotation by the select 6 such as SW of FIG.

FIG. 10 is a schematic diagram illustrating noise control at multiple points in a conventional noise control device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Rotation speed detection part 3 ... Processing part 4 ... Input switch 5 ... Output switch 6 ... SW etc. selection 7 ... SW etc. pattern memory 8, 9 ... Signal conversion part 13 ... Occupant position sensor 200 ... Vehicle interior S1 , S2, S3, S4 ... Speakers M1, M2, M3, M4 ... Microphones

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Kazuhiro Sakiyama 1-2-2 Goshodori, Hyogo-ku, Kobe, Hyogo Prefecture Fujitsu Ten Limited (72) Inventor Masahiro Babasaki 1 Goshodori, Hyogo-ku, Hyogo Prefecture 2-28, Fujitsu Ten Limited (72) Inventor Osamu Ishikawa 1-2-2, Gosho-dori, Hyogo-ku, Kobe, Hyogo Prefecture (2-72) Inside Fujitsu Ten Limited (72) Hideki Kitao Gosho, Kobe-shi, Hyogo Prefecture Fujitsu 1-22 FUJITSU TEN CORPORATION

Claims (4)

[Claims] 1. A noise control device for forming a canceling sound of opposite phase and equal sound pressure to noise at multiple points in a space of a vehicle interior, wherein an error signal due to a residual sound canceling the noise is minimized. A processing unit (3) including an adaptive filter for outputting a plurality of compensation signals for the multipoints, and an error signal from the multipoints being processed by the processing unit (3).
An input switch (4) for controlling the input to the multipoint, an output switch (5) for controlling the output of the compensation signal from the processing unit (3) to the multipoint, the input switch (4) and the output switch Controlling the switching of (5), controlling the processing configuration of the processing unit (3),
Further, the noise control device is provided with a select (6) such as a switch having a pattern memory (7) for storing a switch pattern for performing such control in advance. 2. The selection (6) of the SW or the like detects the number of revolutions of the engine of the vehicle, and the input switch (4) and the output so as to restrict the output of the compensation signal to the required multipoints according to the change of the revolution. A switch for controlling the switch (5).
The described noise control device. 3. The selection (6) of the SW or the like controls the input switch (4) and the output switch (5) so as to detect the position of the occupant and narrow down the output of the compensation signal to the multipoint where the occupant is. 1. The noise control device according to 1. 4. The input switch (4) detects the rotation speed of the engine of the vehicle in the selection (6) of the SW or the like, and synthesizes the input to the processing unit (3) as the rotation speed changes from high rotation to low rotation. And processing unit (3) corresponding to this synthesis.
2. The noise control device according to claim 1, wherein the number of formed compensation signals is controlled to decrease, the filter length of the adaptive filter is increased, and the output switch (5) is controlled to branch and output the compensation signal. .