JPH07160277A - Active silencer and electronic equipment provided with the same - Google Patents

Abstract

PURPOSE:To provide an active silencer and an electronic equipment which can improve silence effect in a ventilation path having a comparatively short length and a large area. CONSTITUTION:Since this device is constituted so that a sound wave generated in a noise source is propagated through plural sound wave propagation paths 12a-12n formed in parallel in an exhausting section 20, actuators 14a-14n and silence error sensors 13a-13n which generate an added sound wave for silence are provided in each sound wave propagation path and a sound wave propagating in the sound wave propagation path are actively silenced, the silence error sensor can accurately detect a silence error in each sound wave propagation path. Also, since an adaptive control signal processing section 1 can accurately control an actuator in each sound wave propagation path, high silence effect can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention allows an additional sound wave having a phase difference of 180 degrees and the same amplitude to interfere with a sound wave emitted from a ventilation path and becoming noise. The present invention relates to an active muffling device that muffles noise in the ventilation passage, and for example, relates to an active muffling device that is suitable for muffling the blowing noise of a cooling fan leaking from a general-purpose computer to the outside.

[0002]

2. Description of the Related Art An active muffling device which muffles a sound wave emitted from a ventilation path to cause noise by interfering an additional sound wave having a phase difference of 180 degrees and the same amplitude, is known. A reference sensor to be obtained, an actuator for supplying an additional sound wave into the air passage, a muffling error sensor, and an adaptive control signal processing unit for controlling the actuator based on output signals of the reference sensor and the muffling error sensor. And such an active muffler is installed in a duct system, an automobile, a refrigerator, etc. to reduce the noise level. In the duct system, in order to improve the frequency characteristics of the muffling, the middle of the duct is divided into multiple sound wave propagation paths, a reference sensor and an actuator are installed in each sound wave propagation path, and the divided sound wave propagation paths are merged at the rear side. The one in which a common noise reduction error sensor is installed in the duct is disclosed in, for example, Japanese Patent Application Laid-Open No. 3-13997.

[0003]

However, since this duct system has a structure in which the reference sensor and the actuator are installed in the sound wave propagation path formed by dividing the ventilation path, when the duct system is adopted in a device with a short ventilation path, the reference sensor is used. As a result, the actuator will approach, which makes control difficult. In addition, since a common sound deadening error sensor is installed in a plurality of sound wave propagation paths at the confluence position behind the plurality of sound wave propagation paths formed by division, a detection error may occur in a device having a large ventilation path. It becomes large, the control accuracy is lowered, and the muffling effect is reduced.

An object of the present invention is to provide an active muffler capable of enhancing the muffling effect in a relatively short and large area ventilation passage.

Another object of the present invention is to provide an electronic device in which the noise level can be effectively reduced by the active silencer.

[0006]

One aspect of the present invention is to provide a reference sensor for noise detection, a muffling actuator installed in a ventilation part and an error sensor for detecting a muffling state, and outputs from the reference sensor and the error sensor. In the active silencer including a signal processing unit that adaptively controls the actuator based on the information stored, the ventilation unit is divided into a plurality of sound wave propagation paths in parallel, and the actuator and the error sensor are provided for each sound wave propagation path. It is characterized in that the signal processing unit is adapted to adaptively control the respective actuators based on the output signals of the reference sensor and the error sensor, and another invention is a reference sensor for noise detection and a ventilation unit. Output from the muffling actuator and the mute state detecting error sensor installed in the, and the reference sensor and the error sensor In active noise reduction apparatus having a signal processing unit for adaptively controlling the actuator based on distribution, it is divided into a plurality of wave propagation path in parallel with the ventilation unit,
The actuator is provided for each of a plurality of adjacent sound wave propagations, the error sensor is provided for each sound wave propagation path, and the signal processing unit adaptively controls each actuator based on output signals of the reference sensor and the error sensor. According to still another aspect of the invention, a reference sensor for noise detection, an actuator for noise reduction installed in an exhaust passage and an error sensor for detecting a noise reduction state, the reference sensor and the error sensor output. In an electronic device including an active silencer having a signal processing unit that adaptively controls the actuator based on the information described above, the exhaust passage is divided into a plurality of sound wave propagation paths in which cooling air exhaust units provided in the main body case are arranged in parallel. According to still another aspect of the invention, the error sensor and the actuator are provided for each sound wave propagation path. A reference sensor for noise detection, a muffling actuator installed in the exhaust passage and an error sensor for detecting a muffling state, and a signal for adaptively controlling the actuator based on information output from the reference sensor and the error sensor In an electronic device provided with an active silencer having a processing section, the exhaust passage is configured by dividing a cooling air exhaust section provided in a main body case into a plurality of parallel sound wave propagation paths, and the reference sensor is an object to be cooled. And the error sensor and the actuator are provided for each of the sound wave propagation paths.

[0007]

The sound wave generated by the noise source propagates through a plurality of parallel sound wave propagation paths formed in the ventilation section or the exhaust path, and each sound wave propagation path includes an actuator for generating additional sound waves for silencing and a sound deadening error sensor. , To mute propagating sound waves.

Since the muffling error sensor can accurately detect the muffling error in each sound wave propagation path, the signal processing unit can accurately control the actuator in each sound wave propagation path.
High muffling effect is obtained.

[0009]

【Example】

First Embodiment This first embodiment is a general-purpose computer in which noise generation is prevented by an active silencer, and will be described with reference to FIGS.

In FIG. 1, reference numeral 1 denotes an adaptive control signal processing unit,
2 is a D / A conversion unit, 3 is a D / A conversion filter unit, 4 is an actuator amplification unit, 5 is an error sensor A / D conversion unit, 6 is an error sensor filter unit, and 7 is an error sensor amplification unit. Section, 8 is an A / D conversion section for reference sensor, 9 is a filter section for reference sensor, 10 is an amplification section for reference sensor, 12
a to 12n are a plurality of sound wave propagation paths configured by dividing the ventilation path of the exhaust section into a plurality of parallel sound paths, and 13a to 13n are muffling errors such as microphones installed on the outlet side of the sound wave propagation paths 12a to 12n. Sensors, 14a to 14n are actuators such as speakers installed on the entrance side of each of the sound wave propagation paths 12a to 12n, 15 is a reference sensor such as a microphone, 16 is a case, 17 is a cooling fan, 18 is a cooling object, and 19 is an inlet. The air part, 20 is an exhaust part, and 21 is a sound absorbing material.

First, the generation of noise will be described. When the cooling fan 17 rotates, the outside air at room temperature or low temperature is sucked in from the air intake part 19, pressurized by the cooling fan 17 to the atmospheric pressure or higher, and discharged toward the cooling object 18 having a heating element (cooling fan). The positions of 17 and the cooling object 18 may be reversed). Here, heat exchange is performed between the room temperature or low temperature air and the heating element of the cooling object 18, and the air having increased thermal energy is discharged from the exhaust unit 20 to the outside. At this time, in the case 16, wind noise and vibration noise of the cooling fan 17 and secondary noise of the cooling object 18 are generated, and this sound wave leaks from the air intake portion 19 and the exhaust portion 20 to the outside to become noise. . Therefore, generally, a sound absorbing material is provided between the air intake portion 19 and the cooling fan 17 and between the cooling material 18 and the exhaust portion 20 so as to absorb the sound wave generated inside the case 16. However, there is a limit to muffling due to absorption, and low-frequency sound waves mainly leak from the exhaust unit 20 and become noise.

A plurality of sound wave propagation paths 1 formed in the exhaust section 20.
2a to 12n, the muffling error sensors 13a to 13n and actuators 14a to 14n installed in the sound wave propagation paths, and the means for controlling these in association with each other, efficiently transmit the sound waves that are going to pass through the ventilation path of the exhaust unit 20. Active mute.

Next, active muffling will be described. In the active noise reduction control, the noise information highly correlated with the noise is transmitted to the reference sensor 1
5, a noise signal is generated, the noise signal is amplified by the reference sensor amplifying unit 10, and only the frequency component that needs to be silenced is taken out by the reference sensor filter unit 9, and the reference sensor A / D conversion is performed. It is converted into a digital signal by the device 8 and input to the adaptive control signal processing unit 1 as noise data.

Further, the muffling leak sound wave propagating to the outlet side of each of the sound wave propagation paths 12a to 12n is transmitted to each muffling error sensor 13a.
To 13n to generate a muffling error signal for each of the sound wave propagation paths 12a to 12n, and the muffling error signal is amplified by the error sensor 7, the error sensor filter 6, and the error sensor A / D converter 5. Through the adaptive control signal processing unit 1
Is input as muffling error data for each of the sound wave propagation paths 12a to 12n.

The adaptive control signal processing unit 1 generates an additional sound control signal for each of the sound wave propagation paths 12a to 12n by adaptive control based on the input noise data and silencing error data, and the D / A conversion unit 2, The actuator 14 via the D / A conversion filter unit 3 and the actuator amplifier 4
a to 14n are controlled to supply additional sound waves for muffling into the sound wave propagation paths 12a to 12n, respectively.
Actively mute the sound waves in n.

Next, the adaptive control by the adaptive control signal processing section 1 will be described with reference to FIG. This figure shows the signal processing function of the adaptive control signal processing unit 1 in blocks. Reference numerals 101a to 101n denote transfer function units for signal processing and 1
02a to 102n are adaptive algorithm units, and 103a to 1
Reference numeral 03n is an equivalent space transfer function section, and 104a to 104n are weighting coefficient multiplication sections.

The noise data obtained by processing the noise source signal output from the reference sensor 15 includes the signal processing transfer function units 101a to 101n and the equivalent spatial transfer function unit 10.
Input to 3a to 103n. Here, the transfer function Cax of the equivalent space transfer function unit 103a is the sound wave propagation path 12a.
From each actuator 14a to each muffling error sensor 13a
To 13n, the transfer function Cbx of the equivalent spatial transfer function unit 103b is the modeling value of the spatial transfer function from the actuator 14b of the sound wave propagation path 12b to the silencing error sensors 13a to 13n,
The transfer function Cnx of the equivalent space transfer function unit 103n is
It is a modeling value of the spatial transfer function from the actuator 14n of the sound wave propagation path 12n to each of the silencing error sensors 13a to 13n. Further, the muffling error sensors 13a to 13n
The muffling error data obtained by processing the muffling error signal output from the above is input to each of the weighting coefficient multiplication units 104a to 104n. Here, for example, the weighting coefficient multiplication unit 104a
Is an arbitrary weighting factor M for each input silencing error data.
Weighting is performed with ax. Similarly, another weight coefficient multiplication unit 1
Also in 04b to 104n, each silencing error data is weighted by an arbitrary weighting coefficient Mbx to Mnx.

The equivalent spatial transfer function sections 103a to 103n corresponding to the sound wave propagation paths 12a to 12n, respectively.
And the signal processing transfer function units 101a-10, which are adapted by the adaptive algorithm units 102a-102n based on the data output from the weight coefficient multiplication units 104a-104n.
The coefficient of 1n is changed at any time, and each actuator 14a to 1
4n enhances the sound deadening effect by optimizing the additional sound waves for sound deadening.

Second Embodiment FIG. 3 shows a modification of the adaptive control by the adaptive control signal processing section 1. The same components as those in the above-mentioned embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. In the figure, 105a to 105n are sound wave propagation paths 12a to 12 respectively.
It is an equivalent space transfer function part dedicated to n. An additional sound wave generated from an actuator 14a installed in a certain sound wave propagation path, for example, the sound wave propagation path 12a is not transmitted to the sound deadening error sensors 13b to 13n of the sound wave propagation paths 12b to 12n other than the sound wave propagation path 12a due to addition of a sound absorbing material or the like. Also, the muffling error sensors 13a to 13n of the sound wave propagation paths 12a to 12n.
When the muffling error signal levels obtained from n are equal, a high active muffling effect can be obtained by independent adaptive control for each of the sound wave propagation paths 12a to 12n. here,
The transfer function Ca of the equivalent space transfer function unit 105a is a modeling value of the space transfer function from the actuator 14a of the sound wave propagation path 12a to the silencing error sensor 13a, and the transfer function Cb of the equivalent space transfer function unit 105b is the sound wave propagation path 12b. Silence error sensor 1 from actuator 14b
The modeling value of the space transfer function up to 3b and the transfer function Cn of the equivalent space transfer function unit 105n are the modeling values of the space transfer function from the actuator 14n of the sound wave propagation path 12n to the silencing error sensor 13n. The other processing functions are the same as those of the processing unit described above.

In this embodiment, each of the adaptive algorithm units 102a to 102n is not weighted to each muffling error data.
, But if necessary, as shown in Figure 4,
By adding the weighting coefficient multiplication unit 106 and modifying the weighting coefficient to be weighted by the weighting coefficient Mx, it is possible to efficiently perform active muffling.

Third Embodiment FIG. 5 and FIG. 6 show a general-purpose electronic computer equipped with an active silencer for applying an additional sound wave generated by one actuator to two adjacent sound wave propagation paths. The same components as those in the above-described embodiment are designated by the same reference numerals.

5 and 6, 1 is an adaptive control signal processing section, 2 is a D / A conversion section, 3 is a D / A conversion filter section, 4 is an actuator amplification section, and 5 is an error sensor A /. D conversion unit, 6 is an error sensor filter unit, 7 is an error sensor amplification unit, 8 is a reference sensor A / D conversion unit,
Reference numeral 9 is a reference sensor filter portion, 10 is a reference sensor amplifying portion, 12a to 12n are a plurality of sound wave propagation paths configured so as to be parallel to each other by dividing the ventilation path of the exhaust part into a plurality, and 13 is the sound wave propagation path 12a. Sound error sensor installed on the exit side of ~ 12n, 14ab ~ 14mn is the sound wave propagation path 12
An actuator installed so as to be shared by two sound wave propagation paths adjacent to the inlet sides of a to 12n, 15 is a reference sensor, 16 is a case, 17 is a cooling fan, 18 is a cooling object,
Reference numeral 19 is an air inlet, 20 is an exhaust, and 21 is a sound absorbing material. In a case where the sound wave propagation paths 12a to 12n are arranged in a two-dimensional matrix, it is possible to install the four sound wave propagation paths so as to share one actuator.

Next, the active silencing control performed by supplying the additional sound wave generated from one actuator to the plurality of sound wave propagation paths will be described.

Similar to the above-described embodiment, noise information having a high correlation with noise is detected by the reference sensor 15 to generate a noise signal, the noise signal is amplified by the reference sensor amplifying section 10, and the frequency component to be silenced. Is extracted by the reference sensor filter unit 9, converted into a digital signal by the reference sensor A / D converter 8 and input to the adaptive control signal processing unit 1 as noise data.

Further, the sound deadening sound waves of the sound wave propagation paths 12a to 12n are detected by the sound deadening error sensors 13a to 12n to generate sound deadening error signals for the respective sound wave propagation paths 12a to 12n. Each acoustic wave propagation path 1 is transmitted to the adaptive control signal processing unit 1 via the sensor amplification unit 7, the error sensor filter unit 6, and the error sensor A / D conversion unit 5.
Input muffling error data for every 2a to 12n.

The adaptive control signal processing unit 1 performs the adaptive control based on the input noise data and silencing error data so that two adjacent sound wave propagation paths 12a, 12b to 12m,
The additional sound control signal is generated every 12n, and the D / A conversion unit 2,
The actuator 14 is controlled via the D / A conversion filter unit 3 and the actuator amplifier 4, and the additional sound wave for silencing is supplied to each of the two sound wave propagation paths 12a, 12b to 12m, 12n, and each sound wave propagation path 12a. Actively mute sound waves within ~ 12n.

The adaptive control signal processing unit 1 for executing such active muffling by adaptive control includes the signal processing transfer function units 101ab to 101mn and the adaptive algorithm unit 102.
ab to 102 mn, equivalent space transfer function units 103 ab to 1
03mn and weighting coefficient multiplication units 104ab to 104mn.

The noise data obtained by processing the noise signal output from the reference sensor 15 includes the signal processing transfer function units 101ab to 101mn and the equivalent spatial transfer function unit 1.
It is input to 03ab-103mn. Here, the transfer function Cabx of the equivalent space transfer function unit 103a is calculated by the muffling error sensors 13a to 13n from the actuator 14ab.
And the transfer function Cmnx of the equivalent spatial transfer function unit 103mn are the modeling values of the spatial transfer functions from the actuator 14mn to the silencing error sensors 13a to 13n. Further, the muffling error data obtained by processing the muffling error signals output from the muffling error sensors 13a to 13n are input to the weighting coefficient multiplication units 104ab to 104mn. Here, for example, the weighting coefficient multiplication unit 104ab weights each input silencing error data with an arbitrary weighting coefficient Mabx. Similarly, in the other weighting coefficient multiplication unit 104mn, each muffling error data is weighted with an arbitrary weighting coefficient Mmnx.

The equivalent spatial transfer function sections 103ab to 103 are provided corresponding to the sound wave propagation paths 12a to 12n.
mn and weighting coefficient multiplication units 104ab to 104mn based on data output from adaptive algorithm units 102ab to 102ab.
The signal processing transfer function unit 1 is adapted at 102 mn.
The coefficient of 01ab to 101mn is changed at any time, and the silencing effect is enhanced by optimizing the additional sound wave for silencing generated from each of the actuators 14ab to 14mn.

Further, for example, the additional sound wave generated from the actuator 14ab is not transmitted to the parts other than the muffling error sensors 13a and 13b due to the addition of the sound absorbing material 21, and the muffling error signal levels obtained from the respective muffling error sensors 13a to 13n are equal. In this case, for example, the actuator 14a
The equivalent space transfer function 103ab from b to the error sensors 13a and 13b, and the error sensors 13 of a1 and a2
It is also possible to perform adaptive control by using each of the silencing error data obtained from a and 13b, which is arbitrarily weighted by the weighting coefficient multiplication units 104ab to 104mn, in each of the adaptive algorithm units 102ab to 102mn.

[0031]

According to the present invention, a sound wave generated by a noise source is propagated through a plurality of parallel sound wave propagation paths formed in a ventilation section or an exhaust path, and a sound deadening is added to each sound wave propagation path. Since a sound wave generating actuator and a sound deadening error sensor are provided to actively mute sound waves propagating in the sound wave propagation path, the sound deadening error sensor can accurately detect the sound deadening error in each sound wave propagation path, and perform signal processing. The section can accurately control the actuator in each sound wave propagation path, and a high silencing effect can be obtained.

Therefore, the sound deadening effect can be enhanced in a relatively short and large area ventilation passage, and a quiet electronic device can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram of a general-purpose computer that is a first embodiment of the present invention.

FIG. 2 is a block diagram showing in detail an adaptive control signal processing unit of the embodiment shown in FIG.

FIG. 3 is a block diagram showing in detail an adaptive control signal processing unit of a general-purpose computer that is a second embodiment of the present invention.

FIG. 4 is a block diagram showing a modified example of the adaptive control signal processing unit of the embodiment shown in FIG.

FIG. 5 is a block diagram of a general-purpose computer that is a third embodiment of the present invention.

6 is a block diagram showing in detail an adaptive control signal processing unit of the embodiment shown in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Adaptive control signal processing part, 12a-12n ... Sound wave propagation path, 13a-13n ... Silence error sensor, 14a-14
n ... actuator, 15 ... reference sensor, 101a-1
01n ... Transfer function unit for signal processing, 102a to 102n ...
Adaptive algorithm unit, 103a to 103n ... Equivalent space transfer function unit, 104a to 104n ... Weighting coefficient multiplication unit.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number for FI Technical indication H03H 21/00 8842-5J // G01H 3/00 A 9215-2G (72) Inventor Osamu Sekiguchi Ibaraki Prefectural Machinery Research Laboratory, Hirata Manufacturing Co., Ltd., Tsuchiura City, Japan (72) Inventor, Makoto Watanabe ▲ Nori ▼ 502, Shinritsu Manufacturing Co., Ltd., Tsuchiura City, Ibaraki Prefecture (72) Inventor Takahiro Oguro Kanagawa Prefecture Horiyamashita, Hadano-shi, 1st General-purpose computer division, Hiritsu Manufacturing Co., Ltd. (72) Inventor Ho Tsukaguchi, 1st, Horiyama-shita, Hadano-shi, Kanagawa Pref. Horiyamashita No. 1 General-purpose computer division, Hiritsu Manufacturing Co., Ltd.

Claims (8)

[Claims] 1. A noise-detecting reference sensor, a noise-reducing actuator installed in a ventilation portion, and a noise-reduction state detecting error sensor, and the actuator based on information output from the reference sensor and the error sensor. In an active silencer including a signal processing unit that adaptively controls, the ventilation unit is divided into a plurality of sound wave propagation paths arranged in parallel, the actuator and an error sensor are provided for each sound wave propagation path, and the signal processing unit is the An active silencer characterized in that each actuator is adaptively controlled based on output signals of a reference sensor and an error sensor. 2. The sound processing device according to claim 1, wherein the signal processing unit includes a weighting coefficient assigning unit that weights the output signal output from each of the error sensors, and a sound wave having a high silencing error level detected by the error sensor. An active silencer characterized by emphasizing adaptive control for a propagation path actuator. 3. A noise-detecting reference sensor, a noise-reducing actuator installed in a ventilation section, and a noise-reduction state detecting error sensor, and the actuator based on information output from the reference sensor and the error sensor. In an active silencer including a signal processing unit for adaptive control, the ventilation unit is divided into a plurality of sound wave propagation paths arranged in parallel, the actuator is provided for each of a plurality of adjacent sound wave propagations, and the error sensor is provided for each sound wave propagation. An active silencer, wherein each signal processing unit is provided for each path and adaptively controls each of the actuators based on the output signals of the reference sensor and the error sensor. 4. The sound processing device according to claim 3, wherein the signal processing unit includes a weighting coefficient assigning unit that weights the output signal output from each of the error sensors, and a sound wave with a high silencing error level detected by the error sensor. An active silencer characterized by emphasizing adaptive control for a propagation path actuator. 5. A reference sensor for noise detection, a muffling actuator installed in an exhaust passage, and an error sensor for detecting a muffling state, and the actuator based on information output from the reference sensor and the error sensor. In an electronic device provided with an active silencer having a signal processing unit for adaptive control, the exhaust passage is configured by dividing a cooling air exhaust unit provided in a main body case into a plurality of acoustic wave propagation paths arranged in parallel, and transmitting each acoustic wave. An electronic device comprising the error sensor and the actuator for each road. 6. The sound processing device according to claim 5, wherein the signal processing unit includes a weighting coefficient giving unit that gives a weight to an output signal output from each of the error sensors, and a sound wave having a high silencing error level detected by the error sensor. An electronic device characterized by focusing on adaptive control for a propagation path actuator. 7. A reference sensor for noise detection, a muffling actuator installed in an exhaust passage, and an error sensor for detecting a muffling state, and the actuator based on information output from the reference sensor and the error sensor. In an electronic device equipped with an active silencer having a signal processing unit for adaptive control, the exhaust passage is configured by dividing a cooling air exhaust unit provided in a main body case into a plurality of acoustic wave propagation paths arranged in parallel, and the reference sensor Is provided in common between the object to be cooled and the cooling air exhaust unit, and the error sensor and the actuator are provided for each of the sound wave propagation paths. 8. The sound processing device according to claim 7, wherein the signal processing unit includes a weighting coefficient giving unit that gives a weight to an output signal output from each of the error sensors, and a sound wave having a large silencing error level detected by the error sensor. An electronic device characterized by focusing on adaptive control for a propagation path actuator.