JPH0659687A - Electronic noise eliminating system - Google Patents
Electronic noise eliminating systemInfo
- Publication number
- JPH0659687A JPH0659687A JP4209959A JP20995992A JPH0659687A JP H0659687 A JPH0659687 A JP H0659687A JP 4209959 A JP4209959 A JP 4209959A JP 20995992 A JP20995992 A JP 20995992A JP H0659687 A JPH0659687 A JP H0659687A
- Authority
- JP
- Japan
- Prior art keywords
- output
- noise
- duct
- differential circuit
- sensor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
- G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
- G10K11/1785—Methods, e.g. algorithms; Devices
- G10K11/17857—Geometric disposition, e.g. placement of microphones
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
- G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
- G10K11/1781—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase characterised by the analysis of input or output signals, e.g. frequency range, modes, transfer functions
- G10K11/17821—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase characterised by the analysis of input or output signals, e.g. frequency range, modes, transfer functions characterised by the analysis of the input signals only
- G10K11/17825—Error signals
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
- G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
- G10K11/1785—Methods, e.g. algorithms; Devices
- G10K11/17853—Methods, e.g. algorithms; Devices of the filter
- G10K11/17854—Methods, e.g. algorithms; Devices of the filter the filter being an adaptive filter
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
- G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
- G10K11/1785—Methods, e.g. algorithms; Devices
- G10K11/17861—Methods, e.g. algorithms; Devices using additional means for damping sound, e.g. using sound absorbing panels
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
- G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
- G10K11/1787—General system configurations
- G10K11/17879—General system configurations using both a reference signal and an error signal
- G10K11/17881—General system configurations using both a reference signal and an error signal the reference signal being an acoustic signal, e.g. recorded with a microphone
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
- G10K2210/10—Applications
- G10K2210/112—Ducts
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Multimedia (AREA)
- Soundproofing, Sound Blocking, And Sound Damping (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】この発明は、ダクト内を伝搬する
騒音を音波干渉により消音する電子消音システムに関す
るものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic silencing system for silencing noise propagating in a duct by acoustic interference.
【０００２】[0002]
【従来の技術】図２は例えば特開平４−７０２００号公
報に示された従来の電子消音システムの断面図であり、
図において１２は第１のセンサマイク、３９は第２のセ
ンサマイク、４０は第３のセンサマイク、１０はダク
ト、１６はダクト１０内に音波を発生するスピーカ、３
２は吸音材、１８はコントローラ、４４は遅延回路、４
８は差動回路である。2. Description of the Related Art FIG. 2 is a sectional view of a conventional electronic silencing system disclosed in, for example, Japanese Patent Laid-Open No. 4-70200.
In the figure, 12 is a first sensor microphone, 39 is a second sensor microphone, 40 is a third sensor microphone, 10 is a duct, 16 is a speaker for generating sound waves in the duct 10, 3
2 is a sound absorbing material, 18 is a controller, 44 is a delay circuit, 4
Reference numeral 8 is a differential circuit.
【０００３】次に、動作を説明する。ダクト１０内を伝
搬する騒音は第１のセンサマイク１２により検出され、
コントローラ１８に送られる。ダクト１０内の送風下流
側に設けられた第２、第３のセンサマイク３９，４０の
うちの第３のセンサマイク４０の出力にはマイク間距離
ｌ分の遅延時間が遅延回路４４により与えられ、かつ第
２のセンサマイク３９の出力と共に差動回路４８に入力
されて減算される。即ち、第２のセンサマイク３９は上
流側からの騒音と下流側からの騒音を集音し、第３のセ
ンサマイク４０は下流側からの騒音を集音するので、差
動回路４８では下流側からの騒音が相殺され、上流側へ
の指向特性を持って騒音が検出される。Next, the operation will be described. The noise propagating in the duct 10 is detected by the first sensor microphone 12,
It is sent to the controller 18. The output of the third sensor microphone 40 of the second and third sensor microphones 39, 40 provided on the downstream side of the air blow in the duct 10 is given the delay time of the inter-microphone distance 1 by the delay circuit 44. , And is input to the differential circuit 48 together with the output of the second sensor microphone 39 to be subtracted. That is, the second sensor microphone 39 collects noise from the upstream side and noise from the downstream side, and the third sensor microphone 40 collects noise from the downstream side. Noise is canceled out, and the noise is detected with the directivity characteristic toward the upstream side.
【０００４】コントローラ１８は第１のセンサマイク１
２及び差動回路４８の出力を入力され、差動回路４８の
出力が最小となるように、スピーカ１６からダクト１０
内を伝搬する騒音と同音圧で逆位相の音波を発生させ
る。ここで、コントローラ１８が有するデジタルフィル
タの係数は消音システム系内の伝達関数の変化に対して
常に最良の係数を持つべく適応制御されており、常に係
数の更新が行われている。こうして、ダクト１０内を伝
搬する騒音は消音され、効果も最良に保たれる。The controller 18 is the first sensor microphone 1
2 and the output of the differential circuit 48 are input so that the output of the differential circuit 48 is minimized from the speaker 16 to the duct 10.
A sound wave having the same sound pressure as that of the noise propagating in the inside and having an opposite phase is generated. Here, the coefficient of the digital filter included in the controller 18 is adaptively controlled so as to always have the best coefficient with respect to the change of the transfer function in the muffling system system, and the coefficient is constantly updated. In this way, the noise propagating in the duct 10 is silenced and the effect is kept at its best.
【０００５】[0005]
【発明が解決しようとする課題】上記のように従来の電
子消音システムにおいては、下流側センサマイクに指向
性を持たせることにより上流側からの伝搬音のみを検出
し、下流側からの騒音によって上流側からの騒音の低減
効果が低下するのを防止し、また系の安定性を確保しよ
うとしていたが、充分ではなかった。As described above, in the conventional electronic silencing system, by directing the downstream side sensor microphone, only the propagation sound from the upstream side is detected, and the noise from the downstream side is detected. Although it was tried to prevent the noise reduction effect from the upstream side from decreasing and to secure the stability of the system, it was not sufficient.
【０００６】この発明は上記のような課題を解決するた
めに成されたものであり、上流側からの騒音の低減効果
及び系の安定性を高めることができる電子消音システム
を得ることを目的とする。The present invention has been made to solve the above problems, and an object thereof is to obtain an electronic silencing system capable of reducing the noise from the upstream side and enhancing the stability of the system. To do.
【０００７】[0007]
【課題を解決するための手段】この発明に係る電子消音
システムは、第３、第２のセンサマイクの出力を遅延さ
せる第１及び第２の遅延回路と、第２のセンサマイクの
出力と第１の遅延回路の出力の差から上流側からの騒音
を検出する第１の差動回路と、第３のセンサマイクの出
力と第２の遅延回路の出力の差から下流側からの騒音を
検出する第２の差動回路と、第１の差動回路の出力が最
小となるようにフィルタ係数を定めてスピーカを制御す
る制御手段と、第２の差動回路の出力が第１の差動回路
の出力より大きいときにフィルタ係数の出力を停止する
手段を設けたものである。SUMMARY OF THE INVENTION An electronic silencing system according to the present invention is provided with first and second delay circuits for delaying the outputs of the third and second sensor microphones, the output of the second sensor microphone and the second delay circuit. The first differential circuit detects noise from the upstream side from the output difference of the first delay circuit, and the noise from the downstream side is detected from the difference between the output of the third sensor microphone and the output of the second delay circuit. And a control means for controlling the speaker by defining a filter coefficient so that the output of the first differential circuit is minimized, and the output of the second differential circuit is the first differential circuit. A means for stopping the output of the filter coefficient when the output of the circuit is larger than that of the circuit is provided.
【０００８】[0008]
【作用】この発明においては、下流側の２つのセンサマ
イクの出力から、上流側からの騒音及び下流側からの騒
音を検出し、下流側からの騒音の方が大きくなった場合
には制御手段のフィルタ係数の更新が停止される。According to the present invention, the noise from the upstream side and the noise from the downstream side are detected from the outputs of the two sensor microphones on the downstream side, and when the noise from the downstream side becomes louder, the control means is provided. The update of the filter coefficient of is stopped.
【０００９】[0009]
【実施例】以下、この発明の実施例を図面とともに説明
する。図１はこの実施例による電子消音システムの構成
を示し、ダクト１０は鋼板からなるダクト壁材９の内周
にグラスウールからなる吸音材８を設けて構成される。
４４，４５は音速距離ｌ分の遅延回路、４８，４９は差
動回路、２２，２４，２５はＡ／Ｄ変換部、２６はＤ／
Ａ変換部である。又、２８はアダプティブ（適応形）デ
ジタルフィルタ、３０は制御部であり、これらによりコ
ントローラ１８が構成される。Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the configuration of an electronic silencing system according to this embodiment. The duct 10 is constructed by providing a sound absorbing material 8 made of glass wool on the inner periphery of a duct wall material 9 made of steel plate.
44 and 45 are delay circuits for a sound velocity distance of 1, 48 and 49 are differential circuits, 22, 24 and 25 are A / D converters, and 26 is D /
It is an A converter. Further, 28 is an adaptive digital filter, 30 is a controller, and these constitute the controller 18.
【００１０】次に、動作を説明する。消音用音波発生ス
ピーカ１６の下流側に設けられた第２、第３のセンサマ
イク３９，４０の出力は第１、第２の遅延回路４４，４
５及び第１、第２の差動回路４８，４９に入力される。
遅延回路４４，４５の遅延時間Ｔは音速Ｃのセンサマイ
ク３９，４０間距離ｌ分（Ｔ＝ｌ／Ｃ）である。従っ
て、差動回路４８の出力は下流側からの伝搬騒音が相殺
されて上流側からの伝搬騒音に比例したものとなり、差
動回路４９からの出力は逆に下流側からの伝搬騒音に比
例したものとなる。Next, the operation will be described. The outputs of the second and third sensor microphones 39 and 40 provided on the downstream side of the sound-deadening sound wave generation speaker 16 are the first and second delay circuits 44 and 4, respectively.
5 and the first and second differential circuits 48 and 49.
The delay time T of the delay circuits 44 and 45 is the distance 1 (T = 1 / C) between the sensor microphones 39 and 40 having the speed of sound C. Therefore, the output of the differential circuit 48 is proportional to the propagation noise from the upstream side by canceling the propagation noise from the downstream side, and the output from the differential circuit 49 is conversely proportional to the propagation noise from the downstream side. Will be things.
【００１１】コントローラ１８は第１のセンサマイク１
２の出力をＡ／Ｄ変換部２２を介して入力されて上流側
からの伝搬騒音を検出するとともに、各差動回路４８，
４９の出力をＡ／Ｄ変換器２４，２５を介して入力さ
れ、第１の差動回路４８の出力が最小となるようにアダ
プティブデジタルフィルタ２８のフィルタ係数を定め、
これに応じてＤ／Ａ変換部２６を介してスピーカ１６か
ら伝搬騒音と同音圧逆位相の音波を発生させ、上流側か
らの伝搬騒音を消音させる。この場合は差動回路４８の
出力が差動回路４９の出力より大きい場合である。The controller 18 is the first sensor microphone 1
The output of 2 is input through the A / D converter 22 to detect the propagation noise from the upstream side, and each differential circuit 48,
The output of 49 is input via the A / D converters 24 and 25, and the filter coefficient of the adaptive digital filter 28 is determined so that the output of the first differential circuit 48 is minimized.
In response to this, a sound wave having the same sound pressure and opposite phase to the propagation noise is generated from the speaker 16 via the D / A conversion unit 26, and the propagation noise from the upstream side is silenced. In this case, the output of the differential circuit 48 is larger than the output of the differential circuit 49.
【００１２】次に、ダクト１０の放射口外騒音が大きく
なり、ダクト１０の放射口から騒音が上流に向って侵入
した場合を考えると、この場合は差動回路４８の出力よ
り差動回路４９の出力の方が大きくなる。従って、ダク
ト１０が放射する騒音はダクト１０外の騒音によりマス
クされ、全体の騒音量への寄与は小さくなる。このよう
な場合には、系の安定性を保つためにアダプティブデジ
タルフィルタ２８のフィルタ係数の更新を停止する。Next, considering the case where the noise outside the radiating port of the duct 10 becomes large and the noise enters from the radiating port of the duct 10 toward the upstream side, in this case, the output of the differential circuit 48 is different from that of the differential circuit 49. The output is larger. Therefore, the noise radiated from the duct 10 is masked by the noise outside the duct 10, and the contribution to the total noise amount is reduced. In such a case, updating of the filter coefficient of the adaptive digital filter 28 is stopped in order to maintain the stability of the system.
【００１３】従って、この実施例では、制御部３０にお
いて各差動回路４８，４９の出力の比較を行い、差動回
路４８の出力の方が大きい場合にはフィルタ係数を更新
しながら通常の消音制御を行い、差動回路４９の出力の
方が大きい場合にはフィルタ係数を固定して消音制御を
行う。Therefore, in this embodiment, the control unit 30 compares the outputs of the differential circuits 48 and 49, and when the output of the differential circuit 48 is larger, the filter coefficient is updated and the normal mute is performed. When the output of the differential circuit 49 is larger, the filter coefficient is fixed and the silencing control is performed.
【００１４】[0014]
【発明の効果】以上のようにこの発明によれば、下流側
に設けた２つのセンサマイクの出力に基づいて上流側か
らの騒音と下流側からの騒音を検出しており、下流側か
らの騒音の方が大きい場合には制御手段のフィルタ係数
の更新を停止するようにしており、系の安定性を高める
ことができる。As described above, according to the present invention, the noise from the upstream side and the noise from the downstream side are detected based on the outputs of the two sensor microphones provided on the downstream side. When the noise is louder, the updating of the filter coefficient of the control means is stopped so that the stability of the system can be enhanced.
【図１】この発明による電子消音システムの構成図であ
る。FIG. 1 is a configuration diagram of an electronic silencing system according to the present invention.
【図２】従来の電子消音システムの構成図である。FIG. 2 is a configuration diagram of a conventional electronic silencing system.
１０ ダクト １２，３９，４０ センサマイク １６ スピーカ １８ コントローラ ２８ アダプティブデジタルフィルタ ３０ 制御部 ４４，４５ 遅延回路 ４８，４９ 差動回路 10 duct 12, 39, 40 sensor microphone 16 speaker 18 controller 28 adaptive digital filter 30 control unit 44, 45 delay circuit 48, 49 differential circuit
Claims (1)
のセンサマイクと、第１のセンサマイクより下流側に設
けられ、ダクト内を伝搬する騒音を検出する第２のセン
サマイクと、第２のセンサマイクより下流側に設けら
れ、ダクト内を伝搬する騒音を検出する第３のセンサマ
イクと、第１と第２のセンサマイク間に設けられ、ダク
ト内に騒音と同音圧で逆位相の音波を発生するスピーカ
と、第３のセンサマイクの出力を第２のセンサマイクと
の距離分だけ遅延させる第１の遅延回路と、第２のセン
サマイクの出力を第３のセンサマイクとの距離分だけ遅
延させる第２の遅延回路と、第２のセンサマイクの出力
と第１の遅延回路の出力の差を求め、上流側からの騒音
を検出する第１の差動回路と、第３のセンサマイクの出
力と第２の遅延回路の出力の差を求め、下流側からの騒
音を検出する第２の差動回路と、第１のセンサマイクの
出力と各差動回路の出力を入力され、第１の差動回路の
出力が最小となるようにフィルタ係数を定め、これに応
じてスピーカを制御する制御手段と、第２の差動回路の
出力が第１の差動回路の出力より大きくなった場合には
フィルタ係数の更新を停止する手段を備えたことを特徴
とする電子消音システム。1. A first detector for detecting noise propagating in a duct.
Sensor microphone, and a second sensor microphone provided downstream of the first sensor microphone for detecting noise propagating in the duct, and a second sensor microphone provided downstream of the second sensor microphone for propagating in the duct A third sensor microphone that detects noise and a speaker that is provided between the first and second sensor microphones and that generates a sound wave of the opposite phase at the same sound pressure as the noise in the duct, and the output of the third sensor microphone. A first delay circuit for delaying the distance from the second sensor microphone, a second delay circuit delaying the output of the second sensor microphone by the distance from the third sensor microphone, and a second sensor The difference between the output of the microphone and the output of the first delay circuit is obtained, and the difference between the output of the first differential circuit that detects noise from the upstream side and the output of the third delay circuit and the output of the second delay circuit is calculated. Second to detect and detect noise from the downstream side Control circuit, the output of the first sensor microphone and the output of each differential circuit are input, the filter coefficient is determined so that the output of the first differential circuit is minimized, and the speaker is controlled accordingly. An electronic silencing system comprising means and means for stopping the updating of the filter coefficient when the output of the second differential circuit becomes larger than the output of the first differential circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4209959A JP2887030B2 (en) | 1992-08-06 | 1992-08-06 | Electronic silencing system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4209959A JP2887030B2 (en) | 1992-08-06 | 1992-08-06 | Electronic silencing system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0659687A true JPH0659687A (en) | 1994-03-04 |
| JP2887030B2 JP2887030B2 (en) | 1999-04-26 |
Family
ID=16581507
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4209959A Expired - Lifetime JP2887030B2 (en) | 1992-08-06 | 1992-08-06 | Electronic silencing system |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2887030B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2003030147A1 (en) * | 2001-09-28 | 2003-04-10 | Takenaka Corporation | Noise reduction apparatus |
| US7492911B2 (en) | 2003-05-15 | 2009-02-17 | Takenaka Corporation | Noise reducing device |
-
1992
- 1992-08-06 JP JP4209959A patent/JP2887030B2/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2003030147A1 (en) * | 2001-09-28 | 2003-04-10 | Takenaka Corporation | Noise reduction apparatus |
| US7492911B2 (en) | 2003-05-15 | 2009-02-17 | Takenaka Corporation | Noise reducing device |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2887030B2 (en) | 1999-04-26 |
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