JPH08146970A - Electronic apparatus mounted with active silencer - Google Patents

Abstract

PURPOSE: To efficiently and stably decrease the noises leaking outside from an electronic apparatus. CONSTITUTION: A casing 1 is provided with fans 2a1 to 2an for cooling an exothermic board group 3. Noises are leaked outside from the casing 1 by these fans 2a1 to 2an and the air blasted therefrom. Plural sound propagation paths 8 are installed on the downstream side of the exothermic board group 3 of this apparatus. The respective propagation paths 8 are internally provided with actuators 4. Propagation paths 7 for mixing provided with reference signal input sensors 5 are installed between the exothermic board group 3 and the propagation paths 8. The noise signals having a high correlation with the noises are detected by the reference signal input sensors 5 and the silencing signals for silencing the noises are formed by a controller 6 based on the noise signals. Silencing with these silencing signals is executed by generating the sound waves for silencing within the respective propagation paths 8 from the actuators 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device equipped with an active muffling device, and more particularly to an electronic device equipped with an active muffling device for actively producing noise to muffle noise.

[0002]

2. Description of the Related Art In the development of computers, communication equipment, electric equipment, etc., high integration has progressed due to the development of small and high-performance products, and a large number of blowers, etc. have been used to suppress the internal heat generated by this. Forced air cooling is performed. As the degree of integration increases, the cooling capacity required for a blower for cooling, in particular, the air volume increases, and accordingly, the noise level increases and the sound environment is impaired. In order to remove this noise, it is known that the noise of the cooling blower or the like is effectively silenced by actively generating sound and destructively interfering with the sound wave.

At present, there is an active muffling apparatus which silences noise generated from an air-cooling blower by interfering a sound wave having a phase difference of 180 degrees with the sound wave and having the same amplitude as the sound wave. As a conventional example in which such an active silencer is used in an electronic device or the like, a method has been proposed in which a duct serving as a noise propagation path is formed along an inner surface of a housing containing the electronic device (for example, Japanese Laid-Open Patent Publication No. HEI5- 232973).

[0004]

In the above prior art, the propagation time until the noise emitted from the noise source propagates in the duct and reaches the duct opening is equal to or longer than the processing time in the active silencer. As described above, the duct is formed along the inner wall of the outer plate of the housing or is formed in a loop shape.
However, no consideration has been given to effectively muffling large blower cooling fan noise.

On the other hand, for a large amount of cooling fan noise, the flow path, that is, the sound wave propagation path is divided into a plurality of parts, that is, the diameter dimension is about 1 of the wavelength corresponding to the maximum frequency to be silenced. There is known a method of dividing into / 2 or less, providing a reference signal input sensor, an actuator, and an error sensor for each propagation path, and silencing each propagation path with an independent sound wave. However, with a large air volume, the number of propagation paths increases, and with this method, the number of each sensor increases according to the number of propagation paths, which leads to an increase in the amount of signal processing, and the cost reduction and compactness that are essential for electronic devices. Inhibit

The sound deadening volume of the active silencer increases in proportion to the degree of correlation between the target noise and the reference signal, that is, the magnitude of coherence. When there are multiple noise sources, if the reference signal input sensor can detect the signal after mixing the sound waves emitted and propagated from them, it is possible to obtain large information on the coherence with each noise source. It is self-evident that the quantity can be expected. However, in the case of an air-cooled electronic device, a plurality of blower noises propagate between heating board groups composed of a plurality of heating boards arranged almost in parallel, but due to the heating board, the sound waves emitted from each sound source are Mixing became insufficient, coherence became small, and sufficient silencing could not be obtained.

An object of the present invention is to provide an air-cooled electronic device that is compact and has a high degree of integration and requires heat exchange by a large amount of air, and is used for air-cooling that is generated from a plurality of blowers and leaks from the inside of the housing to the outside. In the process of propagating the blast sound through a plurality of short propagation paths, the additional sound waves output from the actuators installed in the plurality of propagation paths cause destructive interference and can effectively muffle the sound effectively. An object is to provide an electronic device equipped with a silencer.

Further, since the signal processing speed in the analog signal processing method is remarkably faster than that in the case of a digital circuit, the active silencer can be made compact and inexpensive, but on the other hand, the change of the acoustic propagation speed due to the temperature of the cooling air, the sensor and the actuator. There was a problem that the deterioration of the muffling performance and the unstable operation of the signal processing system of the active muffling device were caused due to the secular change.

Another object of the invention is to take advantage of the advantages of analog signal processing methods, low cost and compactness, and
An object of the present invention is to provide an electronic device equipped with an active muffling device capable of improving deterioration or instability of muffling performance, which is a drawback.

[0010]

In order to achieve the above object, the present invention provides a heat generating board group composed of a plurality of heat generating boards arranged in parallel, and a heat generating board for blowing air to the heat generating board group. A blower for air-cooling a group, a noise detection sensor for detecting noise generated by the blower and the blower of the blower, a sound generation means for generating a sound for silencing the noise, and a noise detected by the noise detection sensor. In an active silencer-equipped electronic device that includes information, and controls the sound generation unit based on the noise information to muffle the noise, the heat generation board group and the blower At least one of the upstream side and the downstream side is provided with a plurality of sound propagation paths, and the sound generation means is provided for each of the propagation paths, and further, the heat generation board group and the propagation path are provided. During or between the blower and the propagation path is obtained by installing the mixing for propagation path for mixing the noise.

Further, according to the present invention, in the active silencer-equipped electronic device having the above structure, a plurality of sound propagation paths are provided on at least one of the heat generating board group and the upstream side and the downstream side of the blower with respect to the blown air. In addition, the sound generation means and the noise detection sensor are provided for each of the propagation paths, and further, a phase filter that delays the phase of the noise signal detected by the noise detection sensor and then outputs the phase difference to the control means is provided. is there.

Furthermore, the present invention provides a heat generating board group composed of a plurality of heat generating boards arranged in parallel, a blower for blowing air to the heat generating board group and air cooling the heat generating board group, and the blower and the blower of the blower. Noise detection sensor for detecting noise generated by the noise detection means, sound generation means for generating a sound for silencing the noise, and noise signal detected by the noise detection sensor, and the sound generation means based on the noise signal. In the active silencer electronic device equipped with a control means for controlling the noise to muffle the noise, and a muffling error detection sensor for detecting the muffling error with respect to the muffling by the sound generating means. At least one of the heat generation board group and the upstream side and the downstream side of the blower, a plurality of sound propagation paths are installed, and the sound generating means is provided for each of the propagation paths. A sound detection sensor and a muffling error detection sensor are provided, and further, a phase filter that delays the phase of the noise signal detected by the noise detection sensor and then outputs it to the control means, and information of the muffling error fetched from the muffling error detection sensor. Based on, to detect the phase delay amount of the sound generated from the sound generating means with respect to the noise, to calculate the optimal phase delay amount of the noise signal in the phase filter based on the data of the phase delay amount, An optimum phase delay amount calculating means for outputting the calculation result to the phase filter is provided.

[0013]

The blower noise and blower noise generated by cooling the heat generating board group by the blower go out of the housing through the mixing propagation path and the plurality of sound propagation paths. At this time, the noise detection sensor provided in the mixing propagation path detects a plurality of pieces of noise information, and the control means creates a muffling signal based on the signal output from the noise detection sensor, and the muffling signal is generated. Is output to the sound generating means. As a result, the sound generating means generates a sound in accordance with the muffling signal output from the control means and actively muffles the blower noise.

If a phase filter for delaying the phase of the noise signal is provided, the blower noise can be reduced by the analog active silencer that gives the signal output from the noise detection sensor an arbitrary phase delay characteristic. Can be actively silenced.

Further, in the case where the muffling error detecting sensor is provided, the muffling error detecting sensor detects the error after the muffling, and based on the information of the muffling error, the phase of the sound generated from the sound generating means with respect to the noise. The amount of delay can be detected. Then, the optimum phase delay amount calculating means calculates the optimum phase delay amount of the noise signal in the phase filter based on the data of the phase delay amount, and outputs the calculation result to the phase filter to adaptively adjust the phase delay characteristic. Can be compensated.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 shows a schematic configuration of an electronic device equipped with an active silencer according to a first embodiment of the present invention. In the figure, 1 is a housing, 2a1 to 2an are blowers, 3 is a heating board group, 4 is an actuator, 5 is a reference signal input sensor, 6 is a controller, 7 is a propagation path for mixing, and 8 is a plurality of sounds. It is a propagation path. And the actuator 4
Are individually provided in the propagation path 8. The actuator 4 constitutes a sound generating means, the reference signal input sensor 5 constitutes a noise detecting sensor, and the controller 6 constitutes a control means.

First, the generation of noise will be briefly described. In order to cool the heat generating board group 3 housed in the housing 1, the blowers 2a1 to 2an housed in the housing 1 are rotated to pressurize the gas and suck the room temperature or low temperature gas from the outside of the housing 1. , Exhale toward the heating board group 3. The blowers 2a1 to 2an and the heat generating board group 3 are arranged in opposite positions, that is, the heat generating board group 3 is located in the peripheral portion of the housing 1 (downward in the figure) and the blowers 2a1 to 2an are located in the central portion of the housing 1 ( They may be arranged at the center).

When the blowers 2a1 to 2an discharge a gas at room temperature or a low temperature toward the heat generating board group 3, heat exchange is performed between the gas and the heat generating board group 3, and the gas having a large heat energy is enclosed in a casing. Exhaled outside the body 1. At this time, in the housing 1, the wind noises of the blowers 2a1 to 2an,
Electromagnetic / structural vibration noise and secondary sound in the heating board group 3 (such as wind noise generated in the heating board group 3 due to the airflow discharged from the blowers 2a1 to 2an) are generated, and the air intake part at normal temperature or low temperature Also, noise leaks to the outside of the housing 1 from the exhaust portion of the gas with increased heat energy. Therefore, sound absorbing materials are often provided before and after the blowers 2a1 to 2an and the heating board group 3. Since the sound absorbing material that can be used for electronic devices that require compactness has a thin plate thickness of several tens of millimeters or less, it is possible to mute high frequency sound waves that are equal to or more than the wavelength of sound waves, but are effective for low and medium frequency sounds. Is extremely small, and noise leaks from the housing 1 even if a sound absorbing material is used.

In the present embodiment, as shown in FIG. 1, between the exhaust side of a gas having a large thermal energy (or the inlet side of a gas at room temperature or low temperature) and a plurality of sound propagation paths 8. A mixing propagation path 7 is provided in the above, whereby a plurality of sounds are mixed in the mixing propagation path 7. Then, the sound wave is actively silenced in the propagation path 8.

The active muffling in this embodiment will be described below. In the active silencing control method, first, a plurality of sound waves that have propagated between the heating board groups 3 are mixed in each space of the mixing propagation path 7. A noise signal having a high correlation with noise is detected by the reference signal input sensor 5 provided substantially corresponding to the mixed sound wave. The muffling signal that can be muted at each of the plurality of sound propagation paths 8 is created by the controller 6 based on the noise signal having a high correlation, and becomes a driving signal for the actuator 4, and each of the plurality of sound propagation paths 8 is generated. It is converted into sound waves for silencing inside. As a result, destructive interference occurs with respect to the noise propagating through the plurality of sound propagation paths 8.

As described above, according to the present embodiment, since active muffling is performed using a small number of reference signal input sensors,
The amount of calculation is small, and the calculation time of the signal processing required therefor can be shortened. As a result, a compact electronic device can be provided, and noise leaking from the housing 1 can be reduced.

(Second Embodiment) FIG. 2 shows a second embodiment of the present invention. In the figure, 1 is a housing, 2a1-2
An is a blower, 3 is a heating board group, 4 is an actuator, 5 is a reference signal input sensor, 6 is a controller, and 9 is a plurality of sound propagation paths, which are the same as those in the first embodiment. The feature of this embodiment is that the phase filter 10 is provided in the middle of the transmission path for transmitting the noise signal detected by the reference signal input sensor 5 to the controller 6.

The mechanism of noise generation is the same as that described in the first embodiment. Therefore, the blower 2a
In many cases, sound absorbing materials are provided before and after 1 to 2 an and the heating board group 3. Even if a sound absorbing material is used, noise is generated in the housing 1.
As shown in FIG. 2, a plurality of sound propagation paths 9 are provided on the exhaust side of the gas with increased thermal energy (or may be on the intake side of the gas at room temperature or low temperature). Active muffling is performed in the sound propagation path 9.

The active muffling in this embodiment will be described below. The active silencing control method is as follows. First, the reference signal input sensor 5 provided for each of the plurality of sound propagation paths 9 detects a noise signal having a high correlation with the noise, and the phase filter 10 detects the noise signal. An arbitrary transfer phase characteristic is given to the noise signal detected on each of the plurality of sound propagation paths 9. Then, the controller 6 creates a silencing signal for silencing the noise at each of the plurality of sound propagation paths 9 based on the noise signal provided with an arbitrary transfer phase characteristic. Next, the muffling signal output from the controller 6 causes the actuator 4 provided in each of the plurality of sound propagation paths 9 to generate a sound wave for silencing in each of the plurality of sound propagation paths 9 The noise propagating through the sound propagation path 9 is destructively interfered with.
Since this phase characteristic can also be realized by an analog type electronic circuit, the signal processing in the controller 6 can be performed by an analog method. Therefore, since an analog-digital converter and a high-speed arithmetic processor are not required, it is possible to perform ultra-high-speed arithmetic, which is a characteristic of analog type, and to realize compact and low cost.

According to this embodiment, active noise reduction is performed, and noise leaking from the housing 1 can be reduced. Although the present embodiment shows an example in which the transfer phase characteristic is given, it goes without saying that a configuration in which the transfer amplitude characteristic is given at the same time may be adopted.

(Third Embodiment) FIG. 3 shows a third embodiment of the present invention. In the figure, 1 is a housing, 2a1-2
an is a blower, 3 is a heating board group, 4 is an actuator, 5 is a reference signal input sensor, 6 is a controller, 9 is a plurality of sound propagation paths, and 10 is a phase filter.
This is the same as in the embodiment. The feature of this embodiment is that the error sensor 11, the phase detector 12, and the signal processor 13 are provided. The error sensor 11 constitutes a silence error detection sensor, and the phase detection unit 12 and the signal processing unit 13 constitute optimum phase delay amount calculation means.

The mechanism of noise generation is the same as that described in the first embodiment. Therefore, the blower 2a
Sound absorbing materials are provided before and after 1 to 2 an and the heating board group 3. Even if this sound absorbing material is used, noise leaks from the housing 1. Therefore, as shown in FIG. 3, the gas exhaust portion side where the thermal energy is large (it may be the room air or low temperature gas inlet portion side). A plurality of sound propagation paths 9 are provided in the above, and active muffling is performed in the plurality of sound propagation paths 9.

The active muffling in this embodiment will be described below. The active silencing control method is as follows. First, the reference signal input sensor 5 provided for each of the plurality of sound propagation paths 9 detects a noise signal having a high correlation with the noise, and the phase filter 10 detects the noise signal. An arbitrary transfer phase characteristic is given to the noise signal detected on each of the plurality of sound propagation paths 9. The controller 6 creates a silencing signal for silencing the noise at each of the plurality of sound propagation paths 9 based on the noise signal provided with an arbitrary transfer phase characteristic.

Next, the muffling signal output from the controller 6 causes a sound wave for muffling to be generated in each of the plurality of sound propagation paths 9 from the actuator 4 provided in each of the plurality of sound propagation paths 9. , Acoustically interferes with the noise propagating through the plurality of sound propagation paths 9. At this time, the error sensor 11 provided for each propagation path of the plurality of sound propagation paths 9 detects the muffling error for each propagation path, and outputs the muffling error signal output from the error sensor 11. And phase detector 1
In step 2, the phase delay of the sound wave for silencing generated from the actuator 4 at the location where the sound is to be silenced is calculated. Then, based on the phase delay signal output from the phase detection unit 12, the signal processing unit 13
Thus, the transfer phase characteristic of the phase filter 10 is changed so that the silencing error becomes small. For example, the phase filter 10
A switched capacitor filter is used as, and the sampling frequency of the switch is made variable in accordance with the silencing error signal.

According to the present embodiment, the advantages of the analog type, such as low cost, compactness accompanying ultra-high speed calculation, that is, shortening of the duct length, and active muffling adaptively, are realized. Since the reduction in reliability and the low volume of sound, which are the drawbacks of (1), can be significantly improved, noise leaking from the housing 1 can be reduced. In the present embodiment, the example of giving the transfer phase characteristic is shown, but of course, a configuration of giving the transfer amplitude characteristic at the same time may be used.

(Fourth Embodiment) FIG. 4 shows a fourth embodiment of the present invention, showing an example of an actuator. In the figure, 14 is a sound propagation path, 15 is a sound absorbing material, 16 is a speaker box, 17 is a speaker, and 18 is a speaker cover.

As shown in the figure, the speaker box 16 to which the speaker 17 is attached is fixed to a hole formed in the wall surface of the sound propagation path 14. And the speaker 1
The vibrating surface of 7 is substantially permeable to sound waves and substantially impermeable to cooling gas so that there is substantially no step with the sound absorbing material 15 (may be absent) attached to the inner surface of the plurality of sound propagation paths 14. It is covered with a transparent speaker cover 18. The actuator of this embodiment is used as the actuator 4 of the above-described first to third embodiments.

(Fifth Embodiment) FIG. 5 shows a fifth embodiment of the present invention, showing another embodiment of the actuator. In the figure, 14 is a sound propagation path, 15 is a sound absorbing material, and 19 is a speaker box, which are the same as in the case of the fourth embodiment.
The feature of this embodiment is that the flat speaker 20 is provided.

As shown in FIG. 5, the flat speaker 20 is attached to a speaker box 19, and the speaker box 19 is fixed to a hole formed in the wall surface of the sound propagation path 14. The vibrating surface of the flat panel speaker 20 is
The sound absorbing member 15 is attached so as to have substantially no step with the sound absorbing member 15 (may be omitted) attached to the inner surface of the sound propagation path 14.

Conventionally, the secondary noise generated by the presence of the step causes the deterioration of the coherence. However, with the configuration of this embodiment, it is possible to realize the increase of the sound deadening level as in the fourth embodiment.

The actuator of this structure is composed of the first to third actuators.
It can be used as the actuator 4 of the embodiment.
Although only the actuator 4 is mentioned in the fourth and fifth embodiments, this configuration can be applied to the reference signal input sensor 5 and the error sensor 11.

(Sixth Embodiment) FIG. 6 shows a sixth embodiment of the present invention, showing an example of a sound propagation path. In the figure, 4
Is an actuator, 5 is a reference signal input sensor, 14 is a sound propagation path, 15 is a sound absorbing material, and 21 is a curved propagation path.

As shown in FIG. 6, a curved propagation path 21 is provided between the reference signal input sensor 5 and the actuator 4 in the sound propagation path 14 to which the sound absorbing material 15 (may be absent) is attached. . When such a curved propagation path 21 is provided, noise in the intermediate frequency band is reduced in the curved propagation path 21, and the low frequency sound that the active silencer is good at can be reduced. Noise in a wide band up to high frequencies can be reduced. Further, when the curved duct is installed at the upper part of the housing so that the duct outlet direction is substantially parallel to the floor surface where the housing is installed, the distance from the floor surface to the upper surface of the curved duct, that is, the height of the active silencer-equipped electronic device can be reduced. In an electronic device equipped with a straight pipe duct without bending, its blowing air sometimes hits the ceiling and impairs the cooling performance. However, this configuration enables the device to be made compact.

The sound propagation path of this configuration can be used as the plurality of sound propagation paths 9 in the first to third embodiments.

(Seventh Embodiment) FIG. 7 is a seventh embodiment of the present invention, showing another embodiment of the sound propagation path. In the figure, 4 is an actuator, 5 is a reference signal input sensor, 1
Reference numeral 4 denotes a plurality of sound propagation paths, 15 a sound absorbing material, and 21 a curved propagation path, which are the same as those in the sixth embodiment. The feature of this embodiment is that a net 22 is provided in the curved propagation path 21.

As shown in FIG. 7, in a plurality of sound propagation paths 14 to which a sound absorbing material 15 (which may not be present) is attached, for example, a reference signal input sensor 5 and an actuator 4 are provided.
A curved propagation path 21 is provided between the two (it is not necessary). Further, for example, a net 22 is inserted in the middle of the sound propagation path downstream of the curved propagation path 21 so that the wind velocity distribution on the cross section of the propagation path becomes as uniform as possible. With this configuration,
Since the maximum wind speed in the cross section of the propagation path 14 can be reduced, it is possible to suppress an increase in secondary generated sound in the duct and pressure loss in the duct. The actuator of this configuration can be used for the plurality of sound propagation paths 9 of the first to third embodiments.

(Eighth Embodiment) FIG. 8 shows an eighth embodiment of the present invention, showing another embodiment of the sound propagation path. In the figure, 4 is an actuator, 5 is a reference signal input sensor, 1
Reference numeral 4 denotes a plurality of sound propagation paths, 15 a sound absorbing material, and 21 a curved propagation path, which are the same as those in the above-described embodiment. The feature of the present embodiment is that the curved propagation path 21 has rounded portions 23a, 2a.
3b is provided.

In this embodiment, as shown in FIG. 8, a curved propagation path between the reference signal input sensor 5 and the actuator 4 in the middle of the sound propagation path 14 to which the sound absorbing material 15 (may be absent) is attached. In FIG. 21, at the corner of the curved propagation path 21, the rounded portion 23 in which the curvature change of the inner surface is gradually smoothed
a and 23b are formed. With such a configuration, the maximum wind speed in the cross section of the propagation path 14 can be reduced, so that the secondary generated sound in the duct and the increase in pressure loss of the duct can be suppressed. The rounded portions 23a and 23b of this embodiment can be used for the bending propagation path 21 of the sixth and seventh embodiments.

(Ninth Embodiment) FIG. 9 is a ninth embodiment of the present invention, showing another embodiment of the sound propagation path. In the figure, 4 is an actuator, 5 is a reference signal input sensor,
Reference numeral 14 is a sound propagation path, 15 is a sound absorbing material, and 21 is a curved propagation path, which are the same as those in the above-described embodiment. The feature of the present embodiment is that the bending propagation path 21 is provided with a straightening plate 24.

In this embodiment, as shown in FIG. 9, a curved propagation path between the reference signal input sensor 5 and the actuator 4 in the middle of the sound propagation path 14 to which the sound absorbing material 15 (may be absent) is attached. A baffle plate 24 is provided at 21. With such a configuration, the maximum wind speed in the cross section of the propagation path 14 can be reduced, so that the secondary generated sound in the duct and the increase in pressure loss of the duct can be suppressed. The current plate 24 of the present embodiment is the sixth
Can be used for the curved propagation path 21 of the eighth embodiment.

(Tenth Embodiment) FIG. 10 shows the first embodiment of the present invention.
0 Example is shown. In the figure, 1 is a housing, 3 is a heating board group, 4 is an actuator, 5 is a reference signal input sensor, 7 is a propagation path for mixing, 8 is a propagation path for a plurality of sounds, 25 is an error sensor, and 26 is Reference signal input sensor amplifier, 27 is reference signal input sensor filter, 28
Is a reference signal input sensor A / D converter, 29 is an error sensor amplifier, 30 is an error sensor filter, 31 is an error sensor A / D converter, 32 is an actuator amplifier, 33 is an actuator filter, 34 Is a D / A converter for actuator, 35 is a digital filter, 36 is an LMS algorithm, 37 is a switch, 38
Is an adaptive digital filter.

For the noise leaking from the housing 1, FIG.
As shown in 0, the mixing propagation path 7 is provided on the exhaust side of the gas having increased thermal energy (or may be on the intake side of the gas at room temperature or at low temperature), and a plurality of mixing propagation paths 7 are provided on the downstream side of the mixing propagation path 7. Propagation paths 8 for individual sounds are provided, and active muffling is performed in these sound propagation paths 8.

The active muffling in this embodiment will be described below. To control the active muffling, first, a reference signal input sensor 5 provided in each space of the mixing propagation path 7 detects a noise signal having a high correlation with noise, and the reference signal input sensor amplifier 26 detects the noise. Amplify the signal. In the amplified noise signal, only the necessary frequency components are discriminated by the reference signal input sensor filter 27, and the reference signal input sensor A
It is converted into digital noise data by the / D converter 28. The digital noise data is convoluted by an adaptive digital filter 38 to create silencing data for silencing at each of the plurality of sound propagation paths 8. The sound deadening data output from the adaptive digital filter 38 is converted into an analog sound deadening signal by the actuator D / A converter 34, and passes through the actuator filter 33 and the actuator amplifier 32 to propagate a plurality of sound propagation paths 8. A sound wave for silencing is generated from the actuator 4 provided on each propagation path and acoustically interferes with noise propagating through the sound propagation path 8.

On the other hand, the error sensor provided for each propagation path of the plurality of sound propagation paths 8 detects the muffling error at each location of the sound propagation path 8, and the error sensor amplifier 29,
Error sensor filter 30 and error sensor A / D
Through the converter 31, it is converted into digital error data. The LMS algorithm 36 updates the coefficient of the adaptive digital filter 38 based on the digital noise data and the digital error data convoluted by the digital filter 35. The coefficient update at this time is performed by dividing the coefficient string of the adaptive digital filter 38 into a plurality of blocks and sequentially for each of these blocks. By the above operation, the active muffling is adaptively performed, and the noise leaking from the housing 1 can be reduced.

Next, the coefficient update will be described with reference to FIG. First, the reference signal input sensor 5
And the signals X and E from the error sensor 25 are input (step 10), and the time series data of the signals X and E are updated (step 101). Signal X and digital filter 35
Create a signal R by convolution of (step 102),
The time series data of the signal R is updated (step 103).
Further, the signal Y is created by convolving the signal X and the adaptive digital filter (step 104), and the signal Y is output (step 105). Furthermore, for example, when the coefficient string of the adaptive digital filter is divided into n blocks, the coefficient group of the first block is updated at the first coefficient update, the coefficient group of the second block is updated at the second coefficient update, and the nth coefficient update is performed. At the time of updating the coefficient of the n-th block and the next updating of the coefficient, the process returns to the beginning to update the coefficient of the first block in order (steps 106 to 108).

In the coefficient updating method, the number of adaptive digital filters 38, which is as many as the number of actuators 4 of the adaptive digital filter 38, is divided into a plurality of parts, and the coefficient is updated for each block to disperse the calculation amount. You can also do it.

FIG. 12 shows an example of the coefficient of the digital filter 35 (corresponding to the impulse response between the actuator 4 and the error sensor 25). As shown in the figure, by setting a threshold value ε for the amplitude value of the coefficient and setting a coefficient smaller than the threshold value ε to 0, the number of taps (the number of coefficients) can be reduced and the amount of calculation can be reduced. Leads to.

Further, in place of the actuator 4 provided for each propagation path of the sound propagation path 8 with a plurality of actuators (may have small diameters), in the muffling signal for driving the actuators, the propagation path 8 is used. It is also possible to reduce the noise propagating through the sound propagation path 8 by controlling the low-frequency sound propagating as a plane wave in each of the propagation paths of 1 in the same manner and controlling the high-frequency sound individually.

Further, when the coefficient of the adaptive digital filter 38 is updated by the LMS algorithm 36 based on the digital noise data convolved by the digital filter 35 and the digital error data, the step width for the update is set to the noise data. And the error data are used for fuzzy reasoning. At this time, the step size for updating is controlled to gradually decrease from, for example, about 0.4.

(Eleventh Embodiment) FIG. 13 shows the eleventh embodiment of the present invention.
An example is shown. In the figure, 4a1 to 4b1,
4a2 to 4c2, 4am to 4dm are actuators, 5
a1 to 5am are reference signal input sensors, 6a1 to 6b1,
6a2 to 6c2 and 6am to 6dm are controllers.

The signal flow will be described with reference to FIG. Controller 6a based on the noise signal from the reference signal input sensor 5a1
Signal processing is performed by 1 to 6b1 and sound waves for silencing are generated from the actuators 4a1 to 4b1, respectively. Further, the controllers 6a2 to 6c2 perform signal processing based on the noise signal from the reference signal input sensor 5a2, and the sound waves for silencing are generated from the actuators 4a2 to 4c2, respectively. Similarly, the controllers 6am to 6dm perform signal processing based on the noise signal of the reference signal input sensor 5am, and the actuators 4am to 4dm generate mute sound waves. The configuration of this embodiment can be used in the first to third embodiments.

(Twelfth Embodiment) FIG. 14 shows the first embodiment of the present invention.
Two examples are shown. In the figure, 4a1 to 4b1
, 4a2 to 4c2, 4am to 4dm are actuators, 5a1 to 5am are reference signal input sensors, and 6a1 to 6
b1, 6a2 to 6c2, 6am to 6dm are controllers, 25a1 to 25b1, 25a2 to 25c2 and 25a
m to 25 dm are error sensors.

The signal flow will be described with reference to FIG. Based on the noise signal from the reference signal input sensor 5a1, the controller 6
Signal processing is performed by a1 to 6b1, and sound waves for silencing are generated from the actuators 4a1 to 4b1, respectively. The mute state at that time is detected by the error sensors 25a1 to 25b1,
The controllers 6a1 to 6b1 are adaptively changed. Further, the controllers 6a2 to 6c2 perform signal processing based on the noise signal from the reference signal input sensor 5a2, and the sound waves for silencing are generated from the actuators 4a2 to 4c2, respectively. The mute state at that time is indicated by the error sensor 25a2.
25c2, and each controller 6a adaptively
Variable from 2 to 6c2. Similarly, based on the noise signal from the reference signal input sensor 5am, the controllers 6am to 6am
signal processing by dm, and each actuator 4am
Generates sound waves of silence from ~ 4 dm. The mute state at that time is detected by the error sensors 25am to 25dm, and the controllers 6am to 6dm are adaptively changed. The configuration of this embodiment can be used in the first to third embodiments.

[0059]

As described above, according to the present invention,
The noise detection sensor can be input with a signal having a high coherence and a blast noise generated from a plurality of air-cooling blowers leaking from the electronic device to the outside, so that the number of noise detection sensors can be minimized. As a result, since the amount of calculation is small, the length of the sound propagation path can be shortened, and a compact active silencer that can efficiently perform stable silencing even for a blower with a large air volume can be obtained. Further, according to the present invention, since the silencing can be performed by the analog signal processing, the accuracy of the silencing processing can be improved.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an electronic device equipped with an active silencer according to a first embodiment of the present invention.

FIG. 2 is an overall configuration diagram of an electronic device with an active silencer according to a second embodiment of the present invention.

FIG. 3 is an overall configuration diagram of an active silencer electronic device according to a third embodiment of the present invention.

FIG. 4 is a configuration diagram of an actuator according to a fourth embodiment of the present invention.

FIG. 5 is a configuration diagram of an actuator according to a fifth embodiment of the present invention.

FIG. 6 is a configuration diagram of a bending propagation path according to a sixth embodiment of the present invention.

FIG. 7 is a configuration diagram of a bending propagation path according to a seventh embodiment of the present invention.

FIG. 8 is a configuration diagram of a bending propagation path according to an eighth embodiment of the present invention.

FIG. 9 is a configuration diagram of a bending propagation path according to a ninth embodiment of the present invention.

FIG. 10 is an overall configuration diagram of an electronic device equipped with an active silencer according to a tenth embodiment of the present invention.

11 is a flowchart of a coefficient updating process in the electronic device equipped with the active silencer of FIG.

12 is a diagram showing a method of reducing an impulse response expression coefficient in the electronic device equipped with the active silencer of FIG.

FIG. 13 is a block diagram showing an example of active silencing according to an eleventh embodiment of the present invention.

FIG. 14 is a block diagram showing another example of active sound deadening according to the twelfth embodiment of the present invention.

[Explanation of symbols]

 1 Case 2a1 to 2an Blower 3 Heating Board Group 4 Actuator 5 Reference Signal Input Sensor 6 Controller 7 Mixing Propagation Path 8, 9, 14 Sound Propagation Path 10 Phase Filter 11, 25 Error Sensor 12 Phase Detection Section 13 Signal Processing Section 15 Sound Absorbing Material 16 Speaker Box 17 Speaker 18 Speaker Cover 19 Speaker Box 20 Planar Speaker 21 Bent Propagation Path 22 Nets 23a, 23b Earle Part 24 Rectifier Plate

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location // H03H 7/20 Z (72) Inventor Yasushi Takano 502 Kandachi-cho, Tsuchiura-shi, Ibaraki Japan Co., Ltd. (72) Inventor Shigeru Koizumi 1 Horiyamashita, Hadano City, Kanagawa Pref., General Computer Division, Hiritsu Manufacturing Co., Ltd. (72) Ho, Tsukaguchi, 1 Horiyamashita, Hadano, Kanagawa Computer Division (72) Inventor Takahiro Oguro 1st Horiyamashita, Hadano City, Kanagawa Prefecture

Claims (19)

[Claims] 1. A heat generating board group composed of a plurality of heat generating boards arranged in parallel, a blower for blowing air to the heat generating board group to cool the heat generating board group, and noise generated by the blower and the air blown by the blower. A noise detection sensor that detects noise, a sound generation unit that generates a sound for canceling the noise, and information about noise detected by the noise detection sensor, and controls the sound generation unit based on the noise information. And a control means for silencing the noise, the electronic device equipped with an active silencer, wherein a plurality of sound propagation paths are provided on at least one of the heating board group and the upstream side and the downstream side of the blower with respect to the blown air. In addition to the installation, the sound generating means is provided for each of the propagation paths, and the noise is reduced between the heat generating board group and the propagation paths or between the blower and the propagation paths. The active silencer mounted electronic device, characterized in that installed mixing for propagation path for sequencing. 2. The active muffler electronic device according to claim 1, wherein the number of the mixing propagation paths is equal to the number of the blowers arranged in the same direction as the direction in which the heating board groups are arranged. An electronic device equipped with an active silencer characterized by being equal. 3. The electronic device with an active sound deadening device according to claim 1, wherein the noise detection sensor is provided for each of the propagation paths for mixing. 4. A heat generating board group composed of a plurality of heat generating boards arranged in parallel, a blower for blowing air to the heat generating board group to cool the heat generating board group, and noise generated by the blower and the blower of the blower. A noise detection sensor for detecting the noise, a sound generation means for generating a sound for silencing the noise, and a noise signal detected by the noise detection sensor, and controlling the sound generation means based on the noise signal. An electronic device equipped with an active silencer, comprising: a control unit for silencing the noise, wherein a plurality of sound propagation paths are provided on at least one of the upstream side and the downstream side of the heating board group and the blower with respect to the blown air. In addition, the sound generation means and the noise detection sensor are provided for each of the propagation paths, and the phase of the noise signal detected by the noise detection sensor is delayed and then the control is performed. The active silencer mounted electronic apparatus characterized in that a phase filter for outputting to the device. 5. The active silencer electronic device according to claim 1, wherein at least one of the sound generating means and the noise detection sensor is capable of substantially transmitting a sound wave at a portion connected to the propagation path. An electronic device with an active silencer, characterized in that the cooling air is covered with a material that is substantially impermeable. 6. A heat generating board group composed of a plurality of heat generating boards arranged in parallel, a blower for blowing air to the heat generating board group to cool the heat generating board group, and noise generated by the blower and the air blown by the blower. A noise detection sensor for detecting the noise, a sound generation means for generating a sound for silencing the noise, and a noise signal detected by the noise detection sensor, and controlling the sound generation means based on the noise signal. An active-noise-reduction-device-equipped electronic device comprising: a control unit configured to muffle the noise; and a muffling error detection sensor configured to detect a muffling error with respect to the muffling by the sound generation unit, wherein the heating board is provided for the blown air. A plurality of sound propagation paths are installed on at least one of the upstream side and the downstream side of the group and the blower, and the sound generating means and the noise detection sensor are provided for each propagation path. And a muffling error detection sensor, further based on a phase filter that delays the phase of the noise signal detected by the noise detection sensor and then outputs to the control means, and the muffling error information fetched from the muffling error detection sensor. , Detecting the phase delay amount of the sound generated from the sound generating means with respect to the noise, and calculating the optimum phase delay amount of the noise signal in the phase filter based on the data of the phase delay amount, the calculation result And an optimum phase delay amount calculating means for outputting to the phase filter. 7. The active silencer electronic device according to claim 6, wherein at least one of the sound generating unit, the noise detecting sensor, and the silence error detecting sensor has a sound wave at a portion connected to the propagation path. An electronic device equipped with an active silencer, which is covered with a material that is substantially permeable to cooling air and substantially impermeable to cooling air. 8. The electronic device equipped with an active silencer according to claim 6, wherein the optimum phase delay amount calculating means is in a propagation path provided with a sound generating means to be controlled among a plurality of silence error detecting sensors. An electronic device with an active silencer, which calculates an optimum phase delay amount based on the silence error information from the silence error detection sensor. 9. The electronic device with active silencer according to claim 4, wherein the phase filter is a switched capacitor filter. 10. The electronic device with active muffler according to claim 1, 2, or 6, wherein the sound generating means is a flat speaker. 11. The electronic device with an active sound deadening device according to claim 1, wherein a net is provided in the middle of the propagation path. 12. The electronic device with active muffler according to claim 1, 2, or 6, wherein a curved portion is formed in the propagation path, and the noise detection sensor and the sound generating means are sandwiched by the curved portion. An electronic device equipped with an active silencer, which is provided. 13. The electronic device with active silencer according to claim 12, wherein an inner surface of the bent portion is formed in a rounded shape. 14. The electronic device with active noise suppressor according to claim 12, wherein a rectifying plate is provided in the bent portion. 15. The electronic device with an active sound deadening device according to claim 1, 2, or 6, wherein the control means controls the sound generating means, of the noise detecting sensors, a noise detecting sensor closest to the sound generating means. An electronic device with an active noise reduction device, which is performed based on noise information from the vehicle. 16. A heat generating board group composed of a plurality of heat generating boards arranged in parallel, a blower for blowing air to the heat generating board group to cool the heat generating board group, and noise generated by the blower and the blower of the blower. A noise detection sensor for detecting the noise, a sound generation means for generating a sound for silencing the noise, and a noise signal detected by the noise detection sensor, and controlling the sound generation means based on the noise signal. An active-noise-reduction-device-equipped electronic device comprising: a control unit configured to muffle the noise; and a muffling error detection sensor configured to detect a muffling error with respect to the muffling by the sound generation unit, wherein the heating board is provided for the blown air. A plurality of sound propagation paths are installed on at least one of the upstream side and the downstream side of the group and the blower, and the sound generating means and the noise detection sensor are provided for each of the propagation paths. And a mute error detection sensor, and further, an adaptive digital filter is provided in the control means, and a calculation amount reduction type signal processing algorithm is used to update the coefficient of the adaptive digital filter for each arbitrarily divided block. An electronic device equipped with an active muffling device, wherein the control means has a built-in function of muffling sound for each block. 17. A heat generating board group composed of a plurality of heat generating boards arranged in parallel, a blower for blowing air to the heat generating board group to cool the heat generating board group, and noise generated by the blower and the air blown by the blower. A noise detection sensor for detecting the noise, a sound generation means for generating a sound for silencing the noise, and a noise signal detected by the noise detection sensor, and controlling the sound generation means based on the noise signal. An active-noise-reduction-device-equipped electronic device comprising: a control unit configured to muffle the noise; and a muffling error detection sensor configured to detect a muffling error with respect to the muffling by the sound generation unit, wherein the heating board is provided for the blown air. A plurality of sound propagation paths are installed on at least one of the upstream side and the downstream side of the group and the blower, and the sound generating means and the noise detection sensor are provided for each of the propagation paths. And a muffling error detection sensor, further, by digitally detecting an impulse response between the sound generating means and the muffling error detection sensor, and ignoring a tap having a value smaller than an arbitrary threshold value in the impulse response. An electronic device with an active silencer, characterized in that the control means has a built-in function of silencing by using a signal processing algorithm for reducing the amount of calculation. 18. A heat generating board group composed of a plurality of heat generating boards arranged in parallel, a blower for blowing air to the heat generating board group to cool the heat generating board group, and noise generated by the blower and the blower of the blower. A noise detection sensor for detecting the noise, a sound generation means for generating a sound for silencing the noise, and a noise signal detected by the noise detection sensor, and controlling the sound generation means based on the noise signal. An active-noise-reduction-device-equipped electronic device comprising: a control unit configured to muffle the noise; and a muffling error detection sensor configured to detect a muffling error with respect to the muffling by the sound generation unit, wherein the heating board is provided for the blown air. A plurality of sound propagation paths are installed on at least one of the upstream side and the downstream side of the group and the blower, and the sound generating means and the noise detection sensor are provided for each of the propagation paths. Preliminary silencing error detecting sensor is provided, further, the step width when updating the transfer function to create a mute signal for the sound generator adaptively,
An electronic device equipped with an active silencer, characterized in that the control means has a built-in function of silencing by using a signal processing algorithm variably controlled by fuzzy inference. 19. A heat generating board group composed of a plurality of heat generating boards arranged in parallel, a blower for blowing air to the heat generating board group to cool the heat generating board group, and noise generated by the blower and the blower of the blower. A noise detection sensor that detects noise, a sound generation unit that generates a sound for canceling the noise, and information about noise detected by the noise detection sensor, and controls the sound generation unit based on the noise information. And a control means for silencing the noise, the electronic device equipped with an active silencer, wherein a plurality of sound propagation paths are provided on at least one of the heating board group and the upstream side and the downstream side of the blower with respect to the blown air. A plurality of the sound generating means are provided for each of the propagation paths, and a low frequency that propagates as a plane wave in the propagation path with respect to the plurality of sound generating means. Controls the same, high frequency sound is active silencer mounted electronic apparatus characterized by the ability to control, it was incorporated in the control means individually.