JPH0219724A - Acoustic spectrum measuring device - Google Patents
Acoustic spectrum measuring deviceInfo
- Publication number
- JPH0219724A JPH0219724A JP16880088A JP16880088A JPH0219724A JP H0219724 A JPH0219724 A JP H0219724A JP 16880088 A JP16880088 A JP 16880088A JP 16880088 A JP16880088 A JP 16880088A JP H0219724 A JPH0219724 A JP H0219724A
- Authority
- JP
- Japan
- Prior art keywords
- band
- measurement
- filter
- value
- measured
- 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
- 238000001228 spectrum Methods 0.000 title claims abstract description 25
- 238000005259 measurement Methods 0.000 claims description 48
- 238000004088 simulation Methods 0.000 claims description 5
- 230000007613 environmental effect Effects 0.000 abstract description 4
- 230000035945 sensitivity Effects 0.000 abstract description 3
- 238000010586 diagram Methods 0.000 description 6
- 238000000034 method Methods 0.000 description 4
- 230000002159 abnormal effect Effects 0.000 description 3
- 238000004364 calculation method Methods 0.000 description 3
- 230000005856 abnormality Effects 0.000 description 2
- 238000000605 extraction Methods 0.000 description 2
- 230000003595 spectral effect Effects 0.000 description 2
- 230000002238 attenuated effect Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000001186 cumulative effect Effects 0.000 description 1
- 238000003745 diagnosis Methods 0.000 description 1
- 238000002592 echocardiography Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 230000000644 propagated effect Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
Landscapes
- Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
Abstract
Description
【発明の詳細な説明】
[産業上の利用分野]
本発明は、産業用機器の機械部から発生する音響を測定
する際、測定点周辺の環境騒音や計測器の周波数に対す
る緩やかな計測誤差の影響などを抑圧して対象とする音
響スペクトルの特徴の抽出を容易にし、異常音を際立た
せ、機器の異常判断、異常部位の推定を容易に行えるよ
うにした音響スペクトル測定装置に関する。[Detailed Description of the Invention] [Industrial Application Field] The present invention is aimed at measuring the gradual measurement error due to the environmental noise around the measurement point and the frequency of the measuring instrument when measuring the sound generated from the mechanical part of industrial equipment. The present invention relates to an acoustic spectrum measurement device that suppresses influences, etc., facilitates extraction of characteristics of a target acoustic spectrum, highlights abnormal sounds, and facilitates determination of abnormalities in equipment and estimation of abnormal parts.
[従来の技術]
従来から産業用機器の機械部の異常を診断するために、
機械部から発生する振動を直接測定するか、又は振動に
よって発生し空気中を伝搬して来る音響を測定すること
が行われていた。[Conventional technology] Conventionally, in order to diagnose abnormalities in the mechanical parts of industrial equipment,
Vibrations generated by mechanical parts have been directly measured, or sound generated by vibrations and propagated through the air has been measured.
機械的振動を其の侭測定することは、大型の工業プラン
ト等で一般的に行われており、正羅な測定ができる。し
かし振動測定は、振動センサを機器に密着させる必要が
あり、予め機器にセンサを装着しておくか、測定時に機
器の適当な部位に接触させて測定しなければならず、前
者では設置費用が高額となり、後者では測定位置が露出
部に制限される。Measuring mechanical vibration from its side is commonly carried out in large industrial plants, etc., and allows accurate measurements. However, in order to measure vibration, it is necessary to place the vibration sensor in close contact with the equipment, and either the sensor must be attached to the equipment in advance or the sensor must be brought into contact with an appropriate part of the equipment during measurement, and the former requires installation costs. The latter method is expensive, and the measurement position is limited to exposed areas.
振動測定に比べて、音響測定は非接触で行うことができ
、手軽に計測できる長所があるが、周囲の雑音や反響音
など所謂環境騒音を拾い、周波数スペクトル上の特徴を
抽出することが困難である。Compared to vibration measurement, acoustic measurement can be performed without contact and has the advantage of being easy to measure, but it picks up so-called environmental noise such as surrounding noise and echoes, making it difficult to extract characteristics on the frequency spectrum. It is.
そのため、従来は、音響測定結果から、スペクトル上の
特徴を抽出するために、第2図に示すように、ある一定
のしきい値以下の音響パワーは雑音と見做し、しきい値
以上の音響スペクトルから特徴を判断する方法や、第3
図に示すように、正常に稼動している状態の音響を標準
値として測定しておいて、それと実稼動時の音響とを比
較する方法(特開昭57−184981号公報記載)な
どが行われていた。Therefore, conventionally, in order to extract spectral features from acoustic measurement results, as shown in Figure 2, acoustic power below a certain threshold is regarded as noise, and acoustic power above the threshold is regarded as noise. How to judge features from acoustic spectra,
As shown in the figure, there is a method (described in Japanese Patent Application Laid-open No. 184981/1983) in which the sound during normal operation is measured as a standard value and compared with the sound during actual operation. I was worried.
[発明が解決しようとする課題]
上記のように、従来の音響スペクトル測定装置では、周
辺環境の雑音の影響が大きく、監視対象機器からの音響
スペクトルの特徴を抽出することが困難であった。この
ような事態に対しては、古くから種々の対策が研究、実
行されており1例えば、「科学計測のための波形データ
処理」(南茂夫編著、昭和61年CQ出版)には、マイ
コン、パソコンを用いて従来実用困難であった手法を実
行することにより、良好な結果が得られるようになった
各種波形データ処理の例が多数記載されているが、これ
らを実際に所謂現場で活用することは必ずしも容易では
なかった。[Problems to be Solved by the Invention] As described above, in the conventional acoustic spectrum measurement device, the influence of noise in the surrounding environment is large, and it is difficult to extract the characteristics of the acoustic spectrum from the device to be monitored. Various countermeasures have been researched and implemented for a long time to deal with such situations. There are many examples of various types of waveform data processing in which good results have been obtained by executing methods that were previously difficult to put into practice using a personal computer, but it is difficult to actually utilize these in the so-called field. It wasn't always easy.
本発明は、監視対象機器で発生している異常音を、極め
て簡易に、検知、抽出できるようにした音響スペクトル
測定装置を提供することを目的とする。SUMMARY OF THE INVENTION An object of the present invention is to provide an acoustic spectrum measuring device that can extremely easily detect and extract abnormal sounds occurring in monitored equipment.
[課題を解決するための手段]
上記目的を達成するために本発明においては、測定対象
音響周波数の全域を、複数の測定帯域に等分し、各測定
帯域に、夫々、帯域通過特性が比較的狭いフィルタと帯
域通過特性が比較的広いフィルタを装備し、各測定帯域
において、狭帯域フィルタによる測定値をPn、広帯域
フィルタによる測定値をP としたとき、Pn、l/P
n、、=P1>1゜または、p、−p、=p2>oとな
る測定帯域に。[Means for Solving the Problems] In order to achieve the above object, the present invention divides the entire range of the acoustic frequencies to be measured into a plurality of measurement bands, and compares the bandpass characteristics of each measurement band. Equipped with a filter with a narrow bandpass characteristic and a filter with a relatively wide bandpass characteristic, and in each measurement band, let Pn be the measured value by the narrowband filter, and P be the measured value by the wideband filter, then Pn, l/P
In the measurement band where n,,=P1>1° or p,-p,=p2>o.
ピーク値が存在し、且つこれらPl又はP2なる値は相
対的ピーク値を表すものと見做すことにした。It was decided that a peak value exists and that these Pl or P2 values represent relative peak values.
[作用]
従来は一般に、上記のような各測定帯域に対して、特定
の帯域通過特性を有する1種類のフィルタだけしか設置
していなかったが、本発明では同一中心周波数を持つ狭
帯域特性のフィルタと広帯域特性のフィルタとを設置し
、狭帯域フィルタを通して高感度で其の帯域内の音響パ
ワーPn、、を拾わせ、広帯域フィルタを通して其の帯
域外の音響パワーをも含めて拾わせる。この場合、広帯
域フィルタを通して得られた音響パワーPwには、環境
騒音が比較的多く含まれていると考えられる。[Function] Conventionally, only one type of filter with specific bandpass characteristics was installed for each measurement band as described above, but in the present invention, narrowband characteristics with the same center frequency are installed. A filter and a filter with wideband characteristics are installed, and the acoustic power Pn within the band is picked up with high sensitivity through the narrowband filter, and the acoustic power outside the band is also picked up through the wideband filter. In this case, it is considered that the acoustic power Pw obtained through the broadband filter contains a relatively large amount of environmental noise.
このような考え方から、突出値を
P l = Pn、1/ Pn、 ・・・(1)P2
=Pn、−Pn、 ・・・(2)として、各測定帯域
毎に測定し、Pl又はP2のスペクトルをとることによ
り、突出した音響パワーを発生している測定帯域を特定
できる。Based on this idea, the salient value is P l = Pn, 1/ Pn, ... (1) P2
=Pn, -Pn, (2) By measuring for each measurement band and taking the spectrum of Pl or P2, it is possible to identify the measurement band in which outstanding acoustic power is being generated.
Plは突出の程度を比率で示しており、PL>1のとき
は突出、Plく1のときはパワーが低いことを示してい
る。P2は突出の程度を差で示しており、P2〉0のと
きは突出、P2<Oのときはパワーが低いことを示して
いる。PL、P2とも値が大きい程、突出の程度が大き
く、相対的ピーク値を示すものと考えて良い。Pl indicates the degree of protrusion as a ratio; PL>1 indicates protrusion, and Pl<1 indicates low power. P2 indicates the degree of protrusion as a difference, and when P2>0, it indicates protrusion, and when P2<O, it indicates that the power is low. The larger the value of both PL and P2, the greater the degree of protrusion, which can be considered to indicate a relative peak value.
なお、2種類のフィルタは、周波数に対してフラットな
音響パワーの入力に対しては、同じ計測値となるように
正規化されていなければならない。Note that the two types of filters must be normalized so that they give the same measurement value for an input of acoustic power that is flat with respect to frequency.
上記のようにすれば、簡便な音響測定器を用いても、音
響スペクトル上の特徴を容易に抽出することができ、産
業用機器の機械部の故障診断などに際して、そのスペク
トルから異常な突出周波数の分布と大きさから故障の診
断や故障部位の推定が容易になる。By doing the above, it is possible to easily extract the features on the acoustic spectrum even using a simple sound measuring instrument, and when diagnosing the failure of the mechanical part of industrial equipment, etc., abnormally prominent frequencies can be detected from the spectrum. It becomes easy to diagnose the failure and estimate the failure location based on the distribution and size of the failure.
本発明実施に際して、各測定帯域に、それぞれ、狭帯域
特性と広帯域特性の2種類のフィルタを装備するのは多
額の費用を要するから、その代りに、狭、又は広の何れ
か一方の同種類の帯域特性のフィルタのみを設置し、こ
れらフィルタを通して得た測定値に適当な処理を施して
、他方の帯域特性の(仮想装備)フィルタによる測定値
を十分な精度でシミュレートできればフィルタの数を半
減できる。When implementing the present invention, it would be costly to equip each measurement band with two types of filters, one with a narrowband characteristic and one with a wideband characteristic. If you install only filters with the band characteristics of 1, apply appropriate processing to the measured values obtained through these filters, and simulate the measured values of the (virtual equipment) filter with the other band characteristic with sufficient accuracy, you can reduce the number of filters. It can be halved.
例えば、各測定帯域に狭帯域特性のフィルタのみを設置
し、これらを通して得た各測定値をPn、ON、 Pn
、□N、・・・とするとき、特定帯域から周波数軸上で
離れるのにつれて、順次1 / 2 (−6dB)に低
減する、帯域ごとの、一般に窓と呼ばれる重みWf (
Wi= 1/2 Wi−□、wi=w−、、Wo”=
1/3、kは帯域の数で表した影響の及ぶ範囲、各帯域
に対する重みの総和は1)を乗じた値を累計したを以っ
て測定帯域fnにおける広帯域特性のフィルタにより測
定した音響パワーのシミュレーション値と見做す。この
ようにして得た(仮想装備)広帯域特性フィルタによる
測定値のシミュレーション値と狭帯域特性フィルタによ
り実温して得た音響パワー値とを前記(1)又は(2)
式に当て嵌めて。For example, only filters with narrowband characteristics are installed in each measurement band, and each measurement value obtained through these filters is Pn, ON, Pn
, □N, ..., the weight Wf (generally called a window) for each band is sequentially reduced to 1/2 (-6 dB) as it moves away from a specific band on the frequency axis.
Wi= 1/2 Wi−□, wi=w−,, Wo”=
1/3, k is the range of influence expressed in the number of bands, and the total weight for each band is the cumulative value multiplied by 1), which is the acoustic power measured by a filter with wideband characteristics in the measurement band fn. It is regarded as a simulation value. The simulated value of the measured value using the wideband characteristic filter obtained in this way (virtual equipment) and the acoustic power value obtained at the actual temperature using the narrowband characteristic filter are combined as described in (1) or (2) above.
Apply it to the formula.
音響スペクトルの突出値を抽出する。Extract the salient values of the acoustic spectrum.
なお、上記(3)式のような乗算や加算は、測定器にマ
イクロコンピュータを内蔵させておくことにより容易に
実行させることが出来る。Note that multiplication and addition as in the above equation (3) can be easily executed by incorporating a microcomputer into the measuring instrument.
実際には、特定測定帯域内では酩一定な低い減衰率を有
し、帯域外では急激に減衰率が高くなる帯域通過特性の
良好な狭帯域フィルタは高価なので、各測定帯域に広帯
域フィルタだけを設置し、これらのフィルタにより得ら
れた測定値がら、狭帯域フィルタにより得られる筈の値
をシミュレートできれば、広帯域フィルタは比較的安価
であるカラ、経済的には好都合である。この場合は、前
述の狭帯域フィルタにより得られた測定値から広帯域フ
ィルタにより得られる筈の値をシミュレートする場合と
、丁度、既知数と未知数を逆転させた形の計算をするこ
とになる。但し、この場合は、仮定した窓の重みが、実
際に使用している広帯域フィルタの特性に良く一致して
いる必要がある。In reality, narrowband filters with good bandpass characteristics, which have a constant low attenuation rate within a specific measurement band and a sharp attenuation rate outside the band, are expensive, so only wideband filters are used in each measurement band. Since wideband filters are relatively inexpensive, it is economically advantageous if the measured values obtained by these filters can be used to simulate the values that would be obtained by narrowband filters. In this case, calculations are performed in which the known and unknown quantities are reversed, similar to when simulating the value that would be obtained by the wideband filter from the measurement value obtained by the narrowband filter described above. However, in this case, the assumed window weights need to closely match the characteristics of the wideband filter actually used.
なお、本発明では、測定対象音響周波数の全域をかなり
多数の測定帯域に分割するから、上記計算はそれだけ多
元の一次連立方程式を解くことになり、マイクロコンピ
ュータを利用するにしても、実際の計算に際しては、例
えば前記「波形データ処理」に記載されているように、
ガウス・ザイデル法を用いるなどの配慮が必要である。In addition, in the present invention, since the entire range of the acoustic frequencies to be measured is divided into quite a large number of measurement bands, the above calculation involves solving multiple linear simultaneous equations, and even if a microcomputer is used, the actual calculation is difficult. For example, as described in "Waveform data processing" above,
Considerations such as using the Gauss-Seidel method are required.
[実施例コ 第1図(a)は本発明の基本原理を説明する図である。[Example code] FIG. 1(a) is a diagram explaining the basic principle of the present invention.
このようにすれば、測定装置は高価なものになるが、測
定値の扱いは簡単になる。なお、現在、マイクロホンは
JISに規定され、性能検定済みの市販品があり、極端
な低周波を除き全可聴周波数域にわたって、略−様な感
度を有するものが入手可能である。In this way, the measuring device becomes expensive, but the measurement values become easier to handle. Currently, there are commercially available microphones that are regulated by JIS and whose performance has been verified, and which have approximately the same sensitivity over the entire audible frequency range except for extremely low frequencies.
第1図(b)は本発明の一実施例図である。測定対象音
響周波数帯域は1〜16kHzで、これを24チヤネル
に分割しである。使用する広帯域フィルタは、隣接チャ
ネル減衰率1/2 (−6dB/チヤネル)の特性を持
つものとする。前記の如く、この実施例で、広帯域フィ
ルタを通して測定した実測値から狭帯域フィルタを通し
て得られる筈の値をシミュレートするためには、24元
連立−次方程式を解かなければならないから、当然マイ
クロコンビコータを利用して処理を行うことになる。FIG. 1(b) is a diagram showing one embodiment of the present invention. The acoustic frequency band to be measured is 1 to 16 kHz, which is divided into 24 channels. It is assumed that the wideband filter used has a characteristic of an adjacent channel attenuation rate of 1/2 (-6 dB/channel). As mentioned above, in this example, in order to simulate the value that should be obtained through the narrowband filter from the actual value measured through the wideband filter, it is necessary to solve the 24-dimensional simultaneous equations, so naturally, the microcombination Processing will be performed using a coater.
本実施例測定装置を用いて、定常回転体を測定した結果
、広帯域フィルタを通して得られた音響パワーの周波数
スペクトルは第4図に示すようになり、これらの値から
計算して得られた狭帯域フィルタを通して得られる筈の
値のシミュレーション結果は第5図に示すようになり、
これら両者の値を比較して抽出された音響スペクトルの
突出値は第6図に示すようになった。As a result of measuring a stationary rotating body using the measurement device of this embodiment, the frequency spectrum of the acoustic power obtained through the wideband filter is shown in Figure 4, and the narrowband frequency spectrum obtained by calculating from these values The simulation results for the values that should be obtained through the filter are shown in Figure 5.
The outstanding values of the acoustic spectrum extracted by comparing these two values are shown in FIG.
このように、高音域側で減衰している音源においても、
的確に突出値を測定できるため、従来は振動測定でしか
特徴をつかめなかったが1本実施例では非接触の音響測
定により、振動の高調波音から、簡便で且つ安価な装置
を用いて、特徴を掴めるようになった。一般に高調波は
高音域では減衰する傾向があるが、本実施例では的確に
特徴を抽出している。なお、本実施例で、測定対象音響
周波数の下端を1 kHzにしたのは、1 k)lz以
下の音響は、回転体の固有振動から発生する音響が大き
く、故障の有無によるスペクトルの差異の抽出が難しい
ため、高調波から、スペクトルの特徴を抽出するように
したのである。In this way, even for sound sources that are attenuated on the high frequency side,
Since the salient value can be accurately measured, the characteristic could previously only be determined by vibration measurement, but in this embodiment, the characteristic can be determined from the harmonic sound of vibration using a simple and inexpensive device, using non-contact acoustic measurement. Now I can grasp it. Generally, harmonics tend to attenuate in the high frequency range, but in this embodiment, the characteristics are accurately extracted. In this example, the lower end of the measurement target acoustic frequency was set to 1 kHz because the sound below 1 kHz is generated from the natural vibration of the rotating body, and the difference in spectrum due to the presence or absence of a failure can be minimized. Since extraction is difficult, we decided to extract spectral features from harmonics.
[発明の効果]
以上説明したように本発明によれば、非接触で音響を計
測し、煩わしい事前の標準計測値の収集などを必要とせ
ず、容易に音響スペクトルの特徴を抽出することが可能
となり、産業用機器の機械部分の故障診断などに応用で
きる。[Effects of the Invention] As explained above, according to the present invention, it is possible to measure sound without contact and easily extract the characteristics of the acoustic spectrum without the need for troublesome collection of standard measurement values in advance. Therefore, it can be applied to failure diagnosis of mechanical parts of industrial equipment.
第1図(a)は本発明の基本原理を説明する図、第1図
(b)は本発明の広帯域フィルタのみを装備した一実施
例図、第2図はしきい値以下の音響パワーは雑音と見做
し、しきい値以上の音響スペクトルから特徴を判断する
従来の方法を示す図、第3図は正常に稼動している状態
の音響を標準値として測定しておいて、それと実稼動時
の音響とを比較する従来の方法を示す図、第4図は広帯
域フィルタのみを装備した本発明実施例装置により定常
回転体を測定して得られた音響パワーの周波数スペクト
ル図、第5図は同実施例実測値から計算して得られた狭
帯域フィルタを通して得られる音響パワーのシミュレー
ション結果を示す図、第6図は前記両者の値を比較して
抽出された音響スペクトルの突出値を示す図である。FIG. 1(a) is a diagram explaining the basic principle of the present invention, FIG. 1(b) is a diagram of an embodiment equipped with only the broadband filter of the present invention, and FIG. 2 is a diagram for explaining the basic principle of the present invention. Figure 3 shows the conventional method of determining characteristics from the sound spectrum above a threshold value, which is considered as noise. Figure 4 is a frequency spectrum diagram of acoustic power obtained by measuring a stationary rotating body using the apparatus according to the present invention equipped with only a broadband filter; The figure shows the simulation results of the acoustic power obtained through the narrowband filter calculated from the actual measurement values of the same example, and Fig. 6 shows the prominent values of the acoustic spectrum extracted by comparing the two values. FIG.
Claims (1)
分し、各測定帯域に、それぞれ、帯域通過特性が比較的
狭いフィルタと帯域通過特性が比較的広いフィルタを装
備し、各測定帯域において、狭帯域フィルタによる測定
値をP_n、広帯域フィルタによる測定値をP_wとし
たとき、P_n/P_w=P1>1、又は、P_n−P
_w=P2>0となる測定帯域に、測定対象のピーク値
が存在し、且つこれらP1又はP2なる値は相対的ピー
ク値を表すものと見做すことを特徴とする音響スペクト
ル測定装置。 2、測定対象音響周波数の全域を、複数に等分した測定
帯域夫々に狭帯域フィルタのみを装備し、これらのフィ
ルタを通して得た実測値に、特定帯域からの周波数の隔
たりに応じて帯域ごとに順次低減する重みを乗じた値を
累計して、該特定帯域に対し仮想広帯域フィルタを通し
て測定した値のシミュレーション値とし、実測およびシ
ミュレーションで得た狭、広帯域フィルタによる値を、
両者の比または差をとって比較し、ピーク値が存在する
測定帯域と其処での相対的ピーク値を推定する音響スペ
クトル測定装置。 3、測定対象音響周波数の全域を複数に等分した測定帯
域夫々に、広帯域フィルタのみを装備し、これらのフィ
ルタを通して得た実測値を、仮想狭帯域フィルタによる
測定値から請求項2記載の如くシミュレーションによっ
て得られたものと見做して、上記広帯域フィルタによる
実測値から逆に仮想狭帯域フィルタによる測定値を算出
し、狭、広帯域フィルタによる値を、両者の比または差
をとって比較し、ピーク値が存在する測定帯域と其処で
の相対的ピーク値を推定する音響スペクトル測定装置。[Claims] 1. The entire range of acoustic frequencies to be measured is divided equally into a plurality of measurement bands, and each measurement band is provided with a filter with a relatively narrow bandpass characteristic and a filter with a relatively wide bandpass characteristic. and in each measurement band, when the measurement value by the narrowband filter is P_n and the measurement value by the wideband filter is P_w, P_n/P_w=P1>1, or P_n-P
An acoustic spectrum measurement device characterized in that a peak value of a measurement target exists in a measurement band where _w=P2>0, and the value P1 or P2 is regarded as representing a relative peak value. 2. The entire range of acoustic frequencies to be measured is divided equally into multiple measurement bands, each of which is equipped with only a narrowband filter, and the actual measured values obtained through these filters are filtered for each band according to the frequency distance from the specific band. The values multiplied by the weights that are sequentially reduced are accumulated to be the simulated value of the value measured through the virtual wideband filter for the specific band, and the values obtained by the narrow and wideband filters obtained through actual measurement and simulation are:
An acoustic spectrum measurement device that compares the ratio or difference between the two to estimate the measurement band where the peak value exists and the relative peak value there. 3. Equipped with only a wideband filter in each measurement band where the entire range of the acoustic frequency to be measured is divided into a plurality of equal parts, and the actual measured values obtained through these filters are converted from the measured values by the virtual narrow band filter as described in claim 2. Assuming that it was obtained by simulation, calculate the measured value using the virtual narrow band filter from the actual measured value using the above wide band filter, and then compare the values obtained using the narrow and wide band filters by taking the ratio or difference between the two. , an acoustic spectrum measurement device that estimates a measurement band where a peak value exists and a relative peak value there.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP16880088A JPH0219724A (en) | 1988-07-08 | 1988-07-08 | Acoustic spectrum measuring device |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP16880088A JPH0219724A (en) | 1988-07-08 | 1988-07-08 | Acoustic spectrum measuring device |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH0219724A true JPH0219724A (en) | 1990-01-23 |
JPH0551852B2 JPH0551852B2 (en) | 1993-08-03 |
Family
ID=15874715
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP16880088A Granted JPH0219724A (en) | 1988-07-08 | 1988-07-08 | Acoustic spectrum measuring device |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH0219724A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2015065352A (en) * | 2013-09-26 | 2015-04-09 | 東レエンジニアリング株式会社 | Substrate floating device |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS62169273A (en) * | 1986-01-22 | 1987-07-25 | Nec Corp | Registration and reference system for label information in language processing program |
JPH0187485U (en) * | 1987-12-02 | 1989-06-09 | ||
JPH03151738A (en) * | 1989-11-08 | 1991-06-27 | Hitachi Ltd | Verification data generating system |
-
1988
- 1988-07-08 JP JP16880088A patent/JPH0219724A/en active Granted
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS62169273A (en) * | 1986-01-22 | 1987-07-25 | Nec Corp | Registration and reference system for label information in language processing program |
JPH0187485U (en) * | 1987-12-02 | 1989-06-09 | ||
JPH03151738A (en) * | 1989-11-08 | 1991-06-27 | Hitachi Ltd | Verification data generating system |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2015065352A (en) * | 2013-09-26 | 2015-04-09 | 東レエンジニアリング株式会社 | Substrate floating device |
Also Published As
Publication number | Publication date |
---|---|
JPH0551852B2 (en) | 1993-08-03 |
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