JPS62105066A - Optical measuring instrument - Google Patents
Optical measuring instrumentInfo
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- JPS62105066A JPS62105066A JP60244986A JP24498685A JPS62105066A JP S62105066 A JPS62105066 A JP S62105066A JP 60244986 A JP60244986 A JP 60244986A JP 24498685 A JP24498685 A JP 24498685A JP S62105066 A JPS62105066 A JP S62105066A
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- Prior art keywords
- light
- output
- receiving element
- light receiving
- polarizer
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- Measuring Magnetic Variables (AREA)
- Measuring Instrument Details And Bridges, And Automatic Balancing Devices (AREA)
Abstract
Description
【発明の詳細な説明】
産業上の利用分野
この発明は高電圧または大電流を光を用いて非接触で計
測する光式計測装置に関するものである。DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to an optical measuring device that measures high voltage or large current using light in a non-contact manner.
従来の技術
従来の光式電流計測装置は、第３図に示すように、発光
ダイオードまたはレーザーダイオードなどの発光素子１
から発する光を偏光子２を通してファラディ素子（磁気
光学効果素子、ファラディローテータ） ３に入射し、
このファラディ素子３から出た光をもう一つのファラデ
ィ素子４に入射し、このファラディ素子４から出た光を
検光子５を通してＰＩＮホトダイオードなどの受光素子
６に入射させるようにしである。ファラディ素子３は検
出すべき電流Ｉが流れる導体７に近接配置し、もう一つ
のファラディ素子４にはコイル８を巻装してあり、パワ
ーアンプ９からコイル８に励磁電流ｉを流すようになっ
ている。また、受光素子６の出力は、プリアンプ１０を
介して最小値検出回路１１に入力され、この最小値検出
回路１１の出力をパワーアンプ９に入力として加えるよ
うになっている。2. Description of the Related Art A conventional optical current measuring device uses a light emitting element 1 such as a light emitting diode or a laser diode, as shown in FIG.
The light emitted from the is incident on a Faraday element (magneto-optic effect element, Faraday rotator) 3 through a polarizer 2,
The light emitted from this Faraday element 3 is made incident on another Faraday element 4, and the light emitted from this Faraday element 4 is made incident on a light receiving element 6 such as a PIN photodiode through an analyzer 5. The Faraday element 3 is placed close to the conductor 7 through which the current I to be detected flows, and the other Faraday element 4 is wound with a coil 8, so that the excitation current i flows from the power amplifier 9 to the coil 8. ing. Further, the output of the light receiving element 6 is inputted to a minimum value detection circuit 11 via a preamplifier 10, and the output of this minimum value detection circuit 11 is applied as an input to a power amplifier 9.
この先代電流計測装置は、発光素子１から出た光を偏光
子２によって直線偏光し、偏光された光をファラディ素
子３に通すと、このファラデイ素子３は電流■に応じて
、すなわち磁界Ｈに応じて偏光面を角度θ１だけ回転さ
せることになる。This predecessor current measuring device linearly polarizes the light emitted from the light emitting element 1 by the polarizer 2, and when the polarized light is passed through the Faraday element 3, the Faraday element 3 responds to the current ■, that is, to the magnetic field H. Accordingly, the plane of polarization is rotated by an angle θ1.
偏光面が角度θ１だけ回転した光をもう一つのファラデ
ィ素子４に通し、このファラディ素子４中で偏光面をコ
イル８に流れる励磁ｉｔ流ｉによってもとにもどすよう
に回転させる。The light whose polarization plane has been rotated by an angle θ1 is passed through another Faraday element 4, and in this Faraday element 4, the polarization plane is rotated back to its original state by the excitation it current i flowing through the coil 8.
そして、ファラディ素子４から出た光を検光子（検光面
が偏光子２の偏光面と直交している）５を通して受光素
子６に入射させ、この受光素子６の出力をプリアンプ１
０で増幅したのち最小値検出回路１１に加える。Then, the light emitted from the Faraday element 4 is made incident on the light receiving element 6 through the analyzer 5 (the analysis plane is perpendicular to the polarization plane of the polarizer 2), and the output of this light receiving element 6 is transmitted to the preamplifier 1.
After the signal is amplified by 0, it is added to the minimum value detection circuit 11.
最小値検出回路１１において、プリアンプ１０の出力レ
ベルを検出し、プリアンプ１０の出力レベルが最小とな
るようにパワーアンプ９への入力端子Ｖを調整すると、
パワーアンプ９への入力電圧■に比例した励磁電流ｉが
コイル８に流れ、これによって生じる磁界によるファラ
ディ素子４における偏光面の回転角θ２が１を流りによ
るファラディ素子３の偏光面の回転角θ１の極性を反転
したものに等しくなる（θ２＝−０１）。このときの電
流ｉ、すなわち電圧■は電流Ｉに比例することになり、
電圧■を求めれば電流Ｉを計測したことになる。When the minimum value detection circuit 11 detects the output level of the preamplifier 10 and adjusts the input terminal V to the power amplifier 9 so that the output level of the preamplifier 10 becomes the minimum,
An excitation current i proportional to the input voltage ■ to the power amplifier 9 flows through the coil 8, and the rotation angle θ2 of the polarization plane in the Faraday element 4 due to the magnetic field generated by this becomes 1. The rotation angle of the polarization plane of the Faraday element 3 due to the flow It is equal to the polarity of θ1 inverted (θ2=-01). At this time, the current i, that is, the voltage ■, is proportional to the current I,
If the voltage ■ is determined, the current I is measured.
ここで、計測原理について数式を用いて説明する。ファ
ラディ素子３における偏光面の回転角θ′は、ファラデ
ィ素子３の長さを２、電流ｌによる磁界をＨ１導体７の
ターン数をＮ、 Ｖ Ｈ、Ｖ ） ’を定数とすれば、
θ１”ｖ！Ｈｊｌ＝ｖ、’Ｎｌ
で表わされ、またフプラディ素子４における偏光面の回
転角θ２は、コイル８に流れる励磁電流をｉ、コイル８
０巻数をｎ５Ｖ２を定数とすれば、θ２ ” Ｖ ２
ｎ ｉ
となる。今、励磁電流ｉの調整によってθ１＝０２
となったとすれば、
ｖ ＩＨｊ！ −Ｖ １’ Ｎ Ｉ ＝ ｖ ２ ｎ
ｉとなり、また、電圧Ｖと励磁電流ｉは、ｋを定数とし
たときに
Ｖ＝ｋ ｉ
の関係があるため、電圧Ｖがわかれば、電流Ｉまたは磁
界Ｈがわかることになる。なお、ファラディ素子３に代
えてポッケルス素子（電気光学効果素子）を用いると電
圧または電界を計測できる。Here, the measurement principle will be explained using mathematical formulas. The rotation angle θ' of the plane of polarization in the Faraday element 3 is given by θ1'', where the length of the Faraday element 3 is 2, the magnetic field due to the current l is H1, the number of turns of the conductor 7 is N, and VH,V)' are constants. v!Hjl=v,'Nl, and the rotation angle θ2 of the plane of polarization in the Hupradi element 4 is expressed as
If the number of turns is 0 and n5V2 is a constant, θ2 ” V 2
n i . Now, if θ1=02 by adjusting the excitation current i, then v IHj! −V 1' N I = v 2 n
Also, since the voltage V and the excitation current i have the relationship V=k i where k is a constant, if the voltage V is known, the current I or the magnetic field H can be found. Note that if a Pockels element (electro-optic effect element) is used in place of the Faraday element 3, the voltage or electric field can be measured.
発明が解決しようとする問題点
このような従来の光式電流計測装置は、ファラディ素子
３の偏光面の回転角θ１とファラディ素子４の偏光面の
回転角θ２とを正確に合致させる必要があり、必要な計
測精度を得るためには、プリアンプ１０．最小値検出回
路１１およびパワーアンプ９としてきわめて精度が高く
、雑音の少いものが必要であるという問題があった。Problems to be Solved by the Invention In such a conventional optical current measuring device, it is necessary to accurately match the rotation angle θ1 of the polarization plane of the Faraday element 3 with the rotation angle θ2 of the polarization plane of the Faraday element 4. , in order to obtain the necessary measurement accuracy, the preamplifier 10. There is a problem in that the minimum value detection circuit 11 and the power amplifier 9 need to be extremely accurate and have little noise.
この発明は、精度の高い機器を必要と廿ずに電流または
電圧を計測することができる先代計測装置を提供するこ
とを目的とする。An object of the present invention is to provide a predecessor measuring device that can measure current or voltage without requiring highly accurate equipment.
問題点を解決するための手段
この発明の先代計測装置は、発光素子と、この発光素子
から出た光を受ける受光素子と、前記発光素子から前記
受光素子へ至る光路の発光素子側に配！した偏光子と、
前記光路の受光素子側に検光面が前記偏光子の偏光面と
４５度の角度で交差するように配置した検光子と、前記
偏光子および検光子の間において前記光路中に配置され
前記偏光子から出た光の偏光面を前記被計測信号に応じ
て回転させる第１の光変調素子と、前記偏光子および検
光子の間において前記光路中に前記第１の光変調素子と
直列に配ｒされた第２の光変調素子と、前記第２の光変
調素子に三角波または鋸歯状のキャリア信号を与え前記
偏光面を前記キャリア信号に応じて高速回転させるキャ
リア信号発生器と、前記受光素子の出力の直流分を抽出
する直流分抽出回路と、この直流分抽出回路の出力と前
記受光素子の出力とのレベル比較を行う比較回路と、こ
の比較回路の出力を復調する復調回路とを備える構成に
したことを特徴とする。Means for Solving the Problems The predecessor measuring device of the present invention includes a light emitting element, a light receiving element that receives light emitted from the light emitting element, and a light emitting element disposed on the light emitting element side of the optical path from the light emitting element to the light receiving element. polarizer and
an analyzer disposed on the light-receiving element side of the optical path so that its analysis plane intersects the polarization plane of the polarizer at an angle of 45 degrees, and an analyzer disposed in the optical path between the polarizer and the analyzer to detect the polarized light a first light modulation element that rotates a polarization plane of light emitted from the light according to the signal to be measured; and a first light modulation element arranged in series with the first light modulation element in the optical path between the polarizer and the analyzer. a carrier signal generator that applies a triangular wave or sawtooth carrier signal to the second optical modulator and rotates the plane of polarization at high speed according to the carrier signal; and the light receiving element. a DC component extracting circuit that extracts a DC component of the output of the DC component, a comparison circuit that compares the level of the output of the DC component extraction circuit and the output of the light receiving element, and a demodulation circuit that demodulates the output of the comparison circuit. It is characterized by its structure.
作用
この発明の光式計測装置は、発光素子と受光素子の間に
偏光面と検光面とが４５度の角度をなすように偏光子と
検光子を配置し、さらに偏光子および検光子の間に第１
および第２の光変調素子を直列に配置し、第１の光変調
素子によって被計測信号を光変調するとともに第２の光
変調素子によって三角波または鋸歯状波キャリア信号を
光変調し、受光素子の出力の直流分を抽出し、この直流
分と受光素子出力とのレベル比較を行うことにより被計
測信号をパルス幅変調してなるパルス幅変調波を作成し
、このパルス幅変調波を復調回路に通すことにより被計
測信号に比例した電圧信号を取出すようにしたものであ
るため、従来例のように高精度かつ低雑音の２機器を必
要とせずに計測を行うことができ、さらに第１の光変調
素子による回転角と第２の光変調素子による回転角の一
致を検出してパルス幅変調を行っているため、発光素子
の光量や光路の減衰量の経時変化に全く影響を受けるこ
とがない。Function The optical measuring device of the present invention has a polarizer and an analyzer arranged between a light emitting element and a light receiving element so that the polarization plane and the analysis plane form an angle of 45 degrees, and 1st in between
and a second optical modulation element are arranged in series, the first optical modulation element optically modulates the signal to be measured, and the second optical modulation element optically modulates the triangular wave or sawtooth wave carrier signal. By extracting the DC component of the output and comparing the level of this DC component with the output of the light receiving element, the measured signal is pulse width modulated to create a pulse width modulated wave, and this pulse width modulated wave is sent to the demodulation circuit. Since the voltage signal proportional to the signal to be measured is extracted by passing the signal through, measurement can be performed without the need for two high-precision, low-noise devices as in the conventional example. Since pulse width modulation is performed by detecting the coincidence of the rotation angle of the light modulation element and the rotation angle of the second light modulation element, it is completely unaffected by changes over time in the amount of light from the light emitting element or the amount of attenuation in the optical path. do not have.
実施例
この発明の一実施例を第１図および第２図に基づいて説
明する。この先代を流計測装置は、第１図に示すように
、発光ダイオードまたはレーザーダイオードなどの発光
素子ｌから発する光を偏光子２を通して第１の光変調素
子であるファラディ素子３に入射し、このファラディ素
子３から出た光を第２の光変調素子であるファラディ素
子４に入射し、このファラディ素子４から出た光を検光
子（検光面が偏光子２の偏光面に対して４５度傾斜して
いる）５を通してＰＩＮホトダイオードｔ４どの受光素
子６に入射させるように構成しである。Embodiment An embodiment of the present invention will be explained based on FIGS. 1 and 2. As shown in FIG. 1, this predecessor flow measuring device makes light emitted from a light emitting element l such as a light emitting diode or a laser diode pass through a polarizer 2 and enter a Faraday element 3, which is a first light modulating element. The light emitted from the Faraday element 3 is incident on the Faraday element 4, which is a second light modulation element, and the light emitted from the Faraday element 4 is passed through an analyzer (the analysis plane is 45 degrees with respect to the polarization plane of the polarizer 2). The configuration is such that the light is incident on any of the light receiving elements 6 through the PIN photodiode t4 (which is tilted).
ファラディ素子３は検出すべき電流Ｉが流れる導体７に
近接配置し、もう一つのファラディ素子４にはコイル８
を巻装してあり、このコイル８に三角波キャリア信号発
生器１２から出力される三角波キャリア信号を加えるよ
うになっている。この場合、三角波キャリア信号の周波
数は、被計測信号に含まれる最大周波数の１０倍以上が
望ましく、例えば被計測信号の周波数範囲がＤＣ〜２Ｋ
ｔｌｚなら、三角波キャリア信号の周波数２０ＫＨｚ以
上となる。The Faraday element 3 is placed close to the conductor 7 through which the current I to be detected flows, and the other Faraday element 4 has a coil 8.
A triangular wave carrier signal output from a triangular wave carrier signal generator 12 is applied to this coil 8 . In this case, the frequency of the triangular wave carrier signal is preferably 10 times or more the maximum frequency included in the signal under measurement, for example, the frequency range of the signal under measurement is DC to 2K.
tlz, the frequency of the triangular wave carrier signal is 20 KHz or more.
また、受光素子６の出力は直流抽出回路１３により直流
分が抽出され、この直流分抽出回路１３により抽出され
た直流分と受光素子６の出力とを比較回路１４で比較す
ることにより計測すべき電＞＆Ｉ（被計測信号）を三角
波キャリア信号でパルス幅変調してなるパルス幅変調信
号に変換し、このパルス幅変調信号中の高周波成分を復
調回路１５で除去することにより電流Ｉに比例した電圧
信号を取り出すようになっている。Further, the output of the light receiving element 6 should be measured by extracting the DC component by the DC extraction circuit 13 and comparing the DC component extracted by the DC component extraction circuit 13 with the output of the light receiving element 6 by the comparison circuit 14. Electric>& I (signal to be measured) is pulse width modulated with a triangular wave carrier signal to convert it into a pulse width modulated signal, and the high frequency component in this pulse width modulated signal is removed by the demodulation circuit 15 to generate a signal proportional to the current I. It is designed to extract voltage signals.
より詳しく説明すると、この先代電流計測装置は、発光
素子１から出た光を偏光子２によって直線偏光し、偏光
された光をファラディ素子３に通すと、このファラディ
素子３は電流Ｉに応じて偏光面を第２図の実線Ａ１のよ
うに回転させる。To explain in more detail, this previous current measuring device linearly polarizes the light emitted from the light emitting element 1 by the polarizer 2, and when the polarized light is passed through the Faraday element 3, the Faraday element 3 The plane of polarization is rotated as shown by the solid line A1 in FIG.
つぎに、ファラディ素子３から出た光はファラディ素子
４に入射するが、このファラディ素子４には三角波キャ
リア信号が加えられているため、ファラディ素子４中で
光は第２図の実線Ａ２で示すように偏光面の回転角が変
化することになる。Next, the light emitted from the Faraday element 3 enters the Faraday element 4, but since a triangular wave carrier signal is added to the Faraday element 4, the light in the Faraday element 4 is shown by the solid line A2 in FIG. The rotation angle of the plane of polarization changes as follows.
この場合、偏光子２の偏光面と検光子５の検光面とが４
５度の角度で交差しているため、電流■による偏光面の
回転角および三角波キャリア信号による偏光面の回転角
の合成回転角と検光子５を通過する光量との間に第２図
の実線Ａ３で示すような関係（１＋ｃｏｓ ２ （θ−
４５”））があり、合成回転角が一４５度のときに零と
なり、＋４５度のときに最大となる。したがって、上記
の回転角は±４５度の範囲内におさめる必要がある。In this case, the polarization plane of the polarizer 2 and the analysis plane of the analyzer 5 are 4
Since they intersect at an angle of 5 degrees, the solid line in Figure 2 is between the composite rotation angle of the rotation angle of the polarization plane due to the current ■ and the rotation angle of the polarization plane due to the triangular wave carrier signal and the amount of light passing through the analyzer 5. The relationship shown in A3 (1+cos 2 (θ-
45")), which becomes zero when the combined rotation angle is 145 degrees and reaches a maximum when it is +45 degrees. Therefore, the above rotation angle needs to be within the range of ±45 degrees.
今、電流■による偏光面の回転に対して三角波キャリア
信号による偏光面の回転方向を逆方向となるように設定
しておけば、ファラディ素子４から出た光を検光子５を
通して受ける受光素子６の出力は、第２図の実線Ａ４で
示すように電流■と三角波キャリア信号とを合成した信
号波形となる。Now, if the rotation direction of the polarization plane by the triangular wave carrier signal is set to be opposite to the rotation of the polarization plane by the current ■, the light receiving element 6 receives the light emitted from the Faraday element 4 through the analyzer 5. The output has a signal waveform that is a combination of the current ■ and the triangular carrier signal, as shown by the solid line A4 in FIG.
この実線Ａ４で示す受光素子６の出力は、電流■による
回転角の変化に応じた出力成分（第２図の破線Ａ５で示
す）と三角波キャリア信号による回転角の変化に応じた
出力成分（第２図の破線Ａ６で示す）とが合成されたも
のである。The output of the light-receiving element 6 shown by the solid line A4 includes an output component corresponding to the change in the rotation angle due to the current ■ (indicated by the broken line A5 in FIG. 2), an output component corresponding to the change in the rotation angle due to the triangular wave carrier signal (indicated by the (shown by the broken line A6 in FIG. 2).
上記受光素子６の出力を直流分抽出回路１３に加えて直
流分（前記の合成回転角が０度に相当する受光素子出力
レベル）を抽出し、この直流分と前記受光素子６の出力
とのレベル比較を比較回路１４にて行えば、第２図の実
ｖＡＡ７に示すようなパルス幅変調波が得られ、このパ
ルス幅変調波を復調回路１５で復１！（高周波成分を除
去）すると電流■に比例した電圧信号が得られることに
なり、この電圧を求めれば、電流■を計測したことにな
る。The output of the light-receiving element 6 is added to the DC component extraction circuit 13 to extract the DC component (the light-receiving element output level corresponding to the composite rotation angle of 0 degrees), and the output of the light-receiving element 6 is combined with the DC component. If the level comparison is performed in the comparator circuit 14, a pulse width modulated wave as shown in the actual vAA7 in FIG. (Remove high frequency components) A voltage signal proportional to the current ■ will be obtained, and if this voltage is determined, the current ■ will be measured.
このように、この実施例は、ｉｉ流Ｉによってファラデ
ィ素子３の回転角を変化させるとともに三角波キャリア
信号によってファラディ素子４の回転角を逆方向に変化
させ、かつ検光子５の検光面と偏光子２の偏光面とが４
５度の角度で交差するように両者を配置し、ファラディ
素子３．４の合成回転角と受光素子６の出力がほぼ比例
関係にある領域で検光を行うことにより電流Ｉと三角波
キャリア信号との合成信号を受光素子６から取り出し、
この合成信号をその中に含まれる直流分とレベル比較す
ることにより、パルス幅変調波を作り、これを復調する
ようにしたため、従来例のような零調整は不要で精度が
高く低雑音の機器は不要となる。また、パルス幅変調を
行っているため、ファラディ素子３．４における偏光面
の回転角が一致するタイミングを検出するだけであって
、発光素子ｌの光量の大小は計測値に無関係であるため
、発光素子１の光量や光路の減衰量の経時変化に全く影
響を受けることはない。In this way, in this embodiment, the rotation angle of the Faraday element 3 is changed by the flow I, and the rotation angle of the Faraday element 4 is changed in the opposite direction by the triangular wave carrier signal, and the analysis plane of the analyzer 5 and the polarization The polarization plane of child 2 is 4
By arranging them so that they intersect at an angle of 5 degrees, and performing analysis in a region where the combined rotation angle of the Faraday element 3.4 and the output of the light receiving element 6 are approximately proportional, the current I and the triangular wave carrier signal can be determined. Take out the composite signal from the light receiving element 6,
By comparing the level of this composite signal with the DC component contained in it, a pulse width modulated wave is created and demodulated, so zero adjustment as in conventional systems is not required, resulting in high precision and low noise equipment. becomes unnecessary. In addition, since pulse width modulation is performed, only the timing at which the rotation angles of the polarization planes in the Faraday elements 3 and 4 match is detected, and the amount of light from the light emitting element l is irrelevant to the measured value. It is completely unaffected by changes over time in the amount of light from the light emitting element 1 or the amount of attenuation of the optical path.
なお、上記実施例では三角波キャリア信号を用いてパル
ス幅変調を行づたが、鋸歯状波をキャリア信号として用
いてもパルス幅変調を行うことができ、鋸歯状波でパル
ス幅変調を行う実施例についてもこの発明範囲に含まれ
るものである。In the above embodiment, pulse width modulation was performed using a triangular wave carrier signal, but pulse width modulation can also be performed using a sawtooth wave as a carrier signal. Examples are also included within the scope of this invention.
また、上記実施例では、ファラディ素子３を用いて電流
を計測するようにしたが、ポッケルス素子（電気光学効
果素子）を使用すれば、電圧を計測することができる。Further, in the above embodiment, the Faraday element 3 is used to measure the current, but a Pockels element (electro-optic effect element) can be used to measure the voltage.
また、ファラディ素子４によって変調を行うようにした
が、ポッケルス素子う用いて変調を行うこともできる。Furthermore, although the Faraday element 4 is used for modulation, a Pockels element may also be used for modulation.
また、キャリアとして、正弦波を用いて位相変調を行う
ことによって電流または電圧を計測することもできる。Further, current or voltage can also be measured by performing phase modulation using a sine wave as a carrier.
この場合の受光素子出力Ｑは、Ｘ。In this case, the light receiving element output Q is X.
Ｙを定数、ω。を搬送波周波数、ω、を信号周波数とす
れば、
Ｑ＝Ｘｃｎｓ （ｓｉｎ ω（ｔ −Ｙｓｉｎ ω３
ｔ）で表わされることになる。Y is a constant, ω. If is the carrier frequency and ω is the signal frequency, then Q=Xcns (sin ω(t −Ysin ω3
t).
発明の効果
この発明の光式計測装置は、発光素子と受光素子の間に
偏光面と検光面が４５度の角度をなすように偏光子と検
光子を配置し、さらに偏光子および検光子の間に第１お
よび第２の光変調素子を直列に配置し、第１の光変調素
子によって被計測信号を光変調するとともに第２の光変
調素子によって三角波または鋸歯状波キャリア信号を光
変調し、受光素子の出力の直流分を抽出し、この直流分
と受光素子出力とのレベル比較を行うことにより被計測
信号をパルス幅変調してなるパルス幅変調波を作成し、
このパルス幅変調波を復調回路に通すことにより被計測
信号に比例した電圧信号を取出すようにしたものである
ため、従来例のように高精度かつ低雑音の機器を必要と
せずに計測を行うことができ、さらに第１の光変調素子
による回転角と第２の光変調素子による回転角の一致を
検出してパルス幅変調を行っているため、発光素子の光
量や光路の減衰量の経時変化に全く影響を受けることが
ない。Effects of the Invention The optical measurement device of the present invention has a polarizer and an analyzer arranged between a light emitting element and a light receiving element so that the polarization plane and the analysis plane form an angle of 45 degrees, and further includes a polarizer and an analyzer. A first and a second optical modulation element are arranged in series between the two, and the first optical modulation element optically modulates the signal to be measured, and the second optical modulation element optically modulates the triangular wave or sawtooth wave carrier signal. Then, by extracting the DC component of the output of the light receiving element and comparing the levels of this DC component and the output of the light receiving element, a pulse width modulated wave is created by pulse width modulating the signal to be measured,
By passing this pulse width modulated wave through a demodulation circuit, a voltage signal proportional to the signal being measured is extracted, so measurements can be performed without the need for high-precision, low-noise equipment as in conventional methods. Furthermore, since pulse width modulation is performed by detecting the coincidence of the rotation angle of the first light modulation element and the rotation angle of the second light modulation element, the amount of light of the light emitting element and the amount of attenuation of the optical path change over time. Not affected by change at all.
第１図はこの発明の一実施例を示すブロック図、第２図
はその動作説明図、第３図は従来例のブロック図である
。
■・・・発光素子、２・・・偏光子、３・・・ファラデ
ィ素子（第１の光変調素子）、４・・・ファラディ素子
（第２の光変調素子）、５・・・検光子、６・・・受光
素子、１３・・・直流分抽出回路、１４・・・比較回路
、１５・・・復調回路FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is an explanatory diagram of its operation, and FIG. 3 is a block diagram of a conventional example. ■... Light emitting element, 2... Polarizer, 3... Faraday element (first light modulation element), 4... Faraday element (second light modulation element), 5... Analyzer , 6... Light receiving element, 13... DC component extraction circuit, 14... Comparison circuit, 15... Demodulation circuit
Claims (1)
と、前記発光素子から前記受光素子へ至る光路の発光素
子側に配置した偏光子と、前記光路の受光素子側に検光
面が前記偏光子の偏光面と４５度の角度で交差するよう
に配置した検光子と、前記偏光子および検光子の間にお
いて前記光路中に配置され前記偏光子から出た光の偏光
面を被計測信号に応じて回転させる第１の光変調素子と
、前記偏光子および検光子の間において前記光路中に前
記第１の光変調素子と直列に配置された第２の光変調素
子と、前記第２の光変調素子に三角波または鋸歯状のキ
ャリア信号を与え前記偏光面を前記キャリア信号に応じ
て高速回転させるキャリア信号発生器と、前記受光素子
の出力の直流分を抽出する直流分抽出回路と、この直流
分抽出回路の出力と前記受光素子の出力とのレベル比較
を行う比較回路と、この比較回路の出力を復調する復調
回路とを備えた光式計測装置。a light-emitting element, a light-receiving element that receives light emitted from the light-emitting element, a polarizer disposed on the light-emitting element side of an optical path from the light-emitting element to the light-receiving element, and an analysis surface on the light-receiving element side of the optical path. An analyzer arranged to intersect the polarization plane of the polarizer at an angle of 45 degrees, and an analyzer arranged in the optical path between the polarizer and the analyzer, and detect the polarization plane of the light emitted from the polarizer as a signal to be measured. a first light modulation element that is rotated according to a carrier signal generator that applies a triangular wave or sawtooth carrier signal to an optical modulation element and rotates the polarization plane at high speed according to the carrier signal; a DC component extraction circuit that extracts a DC component of the output of the light receiving element; An optical measuring device comprising: a comparison circuit that compares the levels of the output of the DC component extraction circuit and the output of the light receiving element; and a demodulation circuit that demodulates the output of the comparison circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60244986A JPS62105066A (en) | 1985-10-31 | 1985-10-31 | Optical measuring instrument |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60244986A JPS62105066A (en) | 1985-10-31 | 1985-10-31 | Optical measuring instrument |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62105066A true JPS62105066A (en) | 1987-05-15 |
| JPH0462354B2 JPH0462354B2 (en) | 1992-10-06 |
Family
ID=17126882
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP60244986A Granted JPS62105066A (en) | 1985-10-31 | 1985-10-31 | Optical measuring instrument |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS62105066A (en) |
-
1985
- 1985-10-31 JP JP60244986A patent/JPS62105066A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0462354B2 (en) | 1992-10-06 |
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