JPS62212543A - Method for discriminating higher-order reflected light from optical fiber defect locating device - Google Patents
Method for discriminating higher-order reflected light from optical fiber defect locating deviceInfo
- Publication number
- JPS62212543A JPS62212543A JP5648086A JP5648086A JPS62212543A JP S62212543 A JPS62212543 A JP S62212543A JP 5648086 A JP5648086 A JP 5648086A JP 5648086 A JP5648086 A JP 5648086A JP S62212543 A JPS62212543 A JP S62212543A
- Authority
- JP
- Japan
- Prior art keywords
- reflected light
- arrival time
- optical fiber
- order
- display
- 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
- 239000013307 optical fiber Substances 0.000 title claims description 28
- 230000007547 defect Effects 0.000 title claims description 7
- 238000000034 method Methods 0.000 title claims description 5
- 239000003550 marker Substances 0.000 abstract description 9
- 230000003287 optical effect Effects 0.000 description 16
- 238000006243 chemical reaction Methods 0.000 description 10
- 238000010586 diagram Methods 0.000 description 8
- 238000005259 measurement Methods 0.000 description 2
- 230000002238 attenuated effect Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
- G01M11/30—Testing of optical devices, constituted by fibre optics or optical waveguides
- G01M11/31—Testing of optical devices, constituted by fibre optics or optical waveguides with a light emitter and a light receiver being disposed at the same side of a fibre or waveguide end-face, e.g. reflectometers
- G01M11/3109—Reflectometers detecting the back-scattered light in the time-domain, e.g. OTDR
- G01M11/3145—Details of the optoelectronics or data analysis
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Optics & Photonics (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- General Physics & Mathematics (AREA)
- Testing Of Optical Devices Or Fibers (AREA)
- Light Guides In General And Applications Therefor (AREA)
Abstract
Description
【発明の詳細な説明】
ｆａ）発明の技術分野
この発明は、光パルスを一定の繰返し周期で光ファイバ
に入射し、光ファイバからの反射パルスを受信して光フ
ァイバの欠陥位置を測定する場合に、光パルスが光ファ
イバの入出力端などを往復するために発生する高次反射
光の位置を識別する方法に関するものである。[Detailed Description of the Invention] fa) Technical Field of the Invention This invention relates to a case where a defect position in an optical fiber is measured by making a light pulse enter an optical fiber at a constant repetition period and receiving a reflected pulse from the optical fiber. In particular, the present invention relates to a method for identifying the position of high-order reflected light generated when a light pulse travels back and forth between the input and output ends of an optical fiber.
（ｂｌ従来技術と問題点
最初に、従来の光ファイバ欠陥位置測定器の構成図を第
２図に示す。(bl Prior Art and Problems First, a block diagram of a conventional optical fiber defect position measuring device is shown in FIG. 2.
第２図の１は光パルス発生回路、２は光スイ。In Fig. 2, 1 is an optical pulse generation circuit, and 2 is an optical switch.
チ、３は光ファイバ、４はＯ／Ｅ変換回路、５はＡ／Ｄ
変換回路、６は表示器、７は近端、８は遠端である。3 is an optical fiber, 4 is an O/E conversion circuit, 5 is an A/D
A conversion circuit, 6 is a display, 7 is a near end, and 8 is a far end.
第２図では、光パルス発生回路１の光パルスを一定の繰
返し周期で光スイツチ２に入射する。In FIG. 2, optical pulses from an optical pulse generating circuit 1 are input to an optical switch 2 at a constant repetition period.
光スイツチ２は方向性結合器のように動作し、光パルス
発生回路１からの光パルスを光ファイバ３に送出すると
ともに、光ファイバ３からの反射パルスをＯ／Ｅ変換回
路４に送出する。The optical switch 2 operates like a directional coupler, and sends out the optical pulse from the optical pulse generation circuit 1 to the optical fiber 3, and sends out the reflected pulse from the optical fiber 3 to the O/E conversion circuit 4.
０／Ｅ変換回路４は光スィッチ２からの反射バルスを電
気信号に変換し、変換出力をＡ／Ｄ変換回路５に送出す
る。The 0/E conversion circuit 4 converts the reflected pulse from the optical switch 2 into an electrical signal and sends the converted output to the A/D conversion circuit 5.
Ａ／Ｄ変換回路５はＯ／Ｅ変換回路４の変換出力をディ
ジタル信号に変換し、表示器６に反射パルスを表示させ
る。The A/D conversion circuit 5 converts the conversion output of the O/E conversion circuit 4 into a digital signal, and causes the display 6 to display the reflected pulse.
次に、光ファイバ３の特性を表示器６に表示したー・例
の波形図を第３図に示す。Next, FIG. 3 shows an example waveform diagram in which the characteristics of the optical fiber 3 are displayed on the display 6.
第３図の１１は光ファイバ３の近端７に対応する表示器
６の始端であり、第３図の右側にいくにしたがって光フ
ァイバ３を進行した光パルスが戻ってくる伏態を示して
いる。Reference numeral 11 in FIG. 3 is the starting end of the indicator 6 corresponding to the near end 7 of the optical fiber 3, and as it goes to the right in FIG. There is.
第３図の１２は近端７による近端反射光であり、１３は
光ファイバ３のレイリー散乱による後方散乱光である。Reference numeral 12 in FIG. 3 is near-end reflected light by the near end 7, and reference numeral 13 is backscattered light due to Rayleigh scattering of the optical fiber 3.
１４は光ファイバ３の遠端８からのフレネル反射光であ
り、１次反射光になる。14 is Fresnel reflected light from the far end 8 of the optical fiber 3, which becomes primary reflected light.
１５は２次反射光１４が光ファイバ３の近端７で再反射
したフレネル反射光であり、２次反射光になる。Reference numeral 15 indicates Fresnel reflected light obtained by re-reflecting the secondary reflected light 14 at the near end 7 of the optical fiber 3, and becomes secondary reflected light.
第３図では、２次反射光１５たけを示しているが、実際
の表示器６の管面には光ファイバ３を往復した高次反射
光が現れて（る。Although FIG. 3 shows only 15 pieces of secondary reflected light, higher-order reflected light that has traveled back and forth through the optical fiber 3 appears on the actual tube surface of the display 6.
後方散乱光１３は、光パルスが右側に進行するにしたが
って左端まで戻ってくる距離が長くなるので、減衰する
。このため、後方散乱光１３は右にいくにつれて右下が
りの曲線になる。The backscattered light 13 is attenuated because the distance it returns to the left end becomes longer as the optical pulse travels to the right. Therefore, the backscattered light 13 becomes a downward-sloping curve as it goes to the right.
第３図の時間ｔは光ファイバ３に入射した光パルスが光
ファイバ３を１往復した時間であり、１次反射光１４の
所要時間を示す。Time t in FIG. 3 is the time required for the optical pulse incident on the optical fiber 3 to make one round trip through the optical fiber 3, and indicates the time required for the primary reflected light 14.
時間２ｔは光ファイバ３に入射した光パルスがファイバ
３を２往復した時間であり、２次反射光１５の所要時間
である。The time 2t is the time required for the optical pulse incident on the optical fiber 3 to travel back and forth through the fiber 3 twice, and is the time required for the secondary reflected light 15.
次に、光ファイバ３の特性を表示器６に表示した他の例
の波形図を第４図に示す。Next, a waveform diagram of another example in which the characteristics of the optical fiber 3 are displayed on the display 6 is shown in FIG.
第４図の１１〜１４は第３図と同じものであり、１７は
２次反射光である。第４図は２次反射光１７が見掛は主
機方散乱光１３に重複して表示された例である。4 are the same as those in FIG. 3, and 17 is secondary reflected light. FIG. 4 is an example in which the secondary reflected light 17 appears to overlap the main engine scattered light 13.
第４図のＴは光パルス発生回路１の送出光パルスの繰返
し周期である。T in FIG. 4 is the repetition period of the optical pulse sent out by the optical pulse generating circuit 1. In FIG.
第４図で、２ｔ＞Ｔの関係にあると、２次反射光１７が
後方散乱光１３と重複して表示されようになる。In FIG. 4, if the relationship 2t>T exists, the secondary reflected light 17 will be displayed overlapping with the backscattered light 13.
第３図や第４図のように、表示４Ｂの管面に後方散乱光
１３以外に別の波形が現れると、それが高次反射光によ
るものなのか光ファイバ３の欠陥によるものなのかを識
別するのが困難になる。When a waveform other than the backscattered light 13 appears on the screen of the display 4B as shown in FIGS. becomes difficult to identify.
（ｃ）発明の目的
この発明は、表示器の管面に現れた１次反射光の位置か
ら高次光反射光の位置を演算で求め、管面に高次反射光
の位置をマーカとして表示することにより、表示器に現
れ・た波形が高次反射光なのかどうかを識別できるよう
にすることを目的とする。(c) Purpose of the Invention This invention calculates the position of higher-order reflected light from the position of primary reflected light appearing on the tube surface of a display device, and displays the position of the higher-order reflected light on the tube surface as a marker. The purpose is to make it possible to identify whether the waveform appearing on the display is high-order reflected light or not.
（ｄ）発明の実施例 まず、この発明による実施例の構成図を第１図に示す。(d) Examples of the invention First, a block diagram of an embodiment according to the present invention is shown in FIG.
第１図の９は１次反射光の到達時間測定手段、１０はｎ
次反射光の到達時間測定手段であり、１〜６は第２図と
同じものである。In FIG. 1, 9 is means for measuring the arrival time of the primary reflected light, and 10 is n
This is a means for measuring the arrival time of the next reflected light, and 1 to 6 are the same as in FIG. 2.
第３図から明らかなように、Ｃ１次反射光は１次反射光
１４の到達時間の整数倍の到達時間を２認とする。この
ため、１次反射光１４の到達時間を測定し、その整数倍
の時間を計算すれば、高次反射光の到達時間が判明する
。As is clear from FIG. 3, the arrival time of the C primary reflected light is an integral multiple of the arrival time of the primary reflected light 14. Therefore, by measuring the arrival time of the primary reflected light 14 and calculating the integral multiple thereof, the arrival time of the higher-order reflected light can be determined.
次に、第３図を参照しながら第１図の到達時間ｉ１＄１
定手段９．１０の動作を説明する。Next, while referring to FIG. 3, the arrival time i1$1 in FIG.
The operation of the determining means 9.10 will now be explained.
最初に、表示″ａ６のカーソルを１次反射光１４の位ｔ
６に合わせ、始端１１から１次反射光１４までの到達時
間ｔを到達特開−１１定手段９で求める。First, move the cursor on the display "a6" to the primary reflected light 14 position t.
6, the arrival time t from the starting end 11 to the primary reflected light 14 is determined by the arrival time t of the first reflected light 14.
次に、到達時間測定手段ｌＯで２℃を求め、表示器６の
２次反射光１５の位置にマーカを表示する。表示′ＪＡ
８の管面に表示するマーカは、１次反射光１４や２次反
射光１５と区別できるように、例えば破線カーソル１６
などを使用する。Next, 2° C. is determined by the arrival time measuring means 1O, and a marker is displayed at the position of the secondary reflected light 15 on the display 6. Display'JA
The marker displayed on the tube surface of 8 is, for example, a broken line cursor 16 so that it can be distinguished from the primary reflected light 14 and the secondary reflected light 15.
etc.
第３図では、破線カーソル１６と２次反射１５が同じ所
にあるので、２次反射光１５は１次反射光１４の２次反
射光であることが分かる。In FIG. 3, since the broken line cursor 16 and the secondary reflection 15 are located at the same place, it can be seen that the secondary reflection light 15 is the secondary reflection light of the primary reflection light 14.
次に、第１図の到達特開−Ｐ１定丁段９．１０の部分の
フローチャートを第５図に示す。Next, FIG. 5 shows a flowchart of the section 9.10 of the Japanese Patent Laid-open Publication No. 2003-110000-P1 fixed stage in FIG. 1.
第５図のフローチャートは、表示器６のカーソルを移動
させた場合、１回ごとにフローさせる。The flowchart in FIG. 5 causes the flow to flow every time the cursor on the display 6 is moved.
ステップ２１では、近端反射光１２の位置に表示器６の
マーカを移動し、時間ｔ１を決める。In step 21, the marker on the display 6 is moved to the position of the near-end reflected light 12, and time t1 is determined.
第３図では、ｔ１＝０としている。In FIG. 3, t1=0.
ステップ２２では、近端反射光１２の位置から１次反射
光１４の位置まで表示器６のマーカを移動し、到達時間
測定手段９により、時間℃２を決める。In step 22, the marker on the display 6 is moved from the position of the near-end reflected light 12 to the position of the primary reflected light 14, and the arrival time measuring means 9 determines the time C2.
ステップ２３では、到達時間測定手段１０により、ｎ次
反射光の位置を次の式（１）で計算する。In step 23, the arrival time measuring means 10 calculates the position of the n-th reflected light using the following equation (1).
Ｔ、１：ｎ（ｔ、〜ｔ 、 ） ＋ ｔ 、 ・・・
−−−−−−・・・（１）式日）のＴｒｌは、ｎ次反射
光である。T, 1:n(t, ~t, ) + t, ...
--------... (1) Trl is n-th reflected light.
ステップ２４では、式（口で計算したＴ４が周期Ｔより
小さいかどうかを判断し、小さい場合はステップ２６に
進む。In step 24, it is determined whether T4 calculated using the formula (original) is smaller than the period T, and if it is smaller, the process proceeds to step 26.
Ｔｎ＜Ｔの場合は、第３図のように高次反射光が１次反
射光１４より右側に現れる。When Tn<T, the higher-order reflected light appears on the right side of the primary reflected light 14 as shown in FIG.
Ｔ ｎ ＞ Ｔの場合は、第４図のように高次反射光が
１次反射光１４の左側に現れ、高次反射光が後方散乱光
１３に１復して表示されるので、そのときはステップ２
５で処理する。When T n > T, the higher-order reflected light appears to the left of the primary reflected light 14 as shown in Fig. 4, and the higher-order reflected light is displayed once again on the backscattered light 13. is step 2
Process in step 5.
ステップ２５では、Ｔ ｎ Ｔを演算し、その結果が
Ｔｎ＜Ｔになるまでステップ２４とステップ２５を繰り
返す。In step 25, T n T is calculated, and steps 24 and 25 are repeated until the result is Tn<T.
ステップ２１〜２５で高次反射光の位置が求められるの
で、その位置に破線マーカ１６なとを表示する。Since the position of the high-order reflected light is determined in steps 21 to 25, a broken line marker 16 is displayed at that position.
（ｅ）発明の効果
この発明によれば、１次反射光の到達時間測定手段と高
次反射光の到達時間測定手段を採用しているので、高次
反射光の位置を表示器上にマーカとして表示することが
でき、高次反射光による波形なのか実際の波形なのかを
容易に区別することができる。(e) Effects of the Invention According to the present invention, since the arrival time measuring means of the primary reflected light and the arrival time measuring means of the higher-order reflected light are employed, the position of the higher-order reflected light can be marked on the display. It is possible to easily distinguish whether the waveform is caused by higher-order reflected light or the actual waveform.
したがって、実際の測定で高次反射光による誤測定を少
なくすることができる。Therefore, erroneous measurements due to higher-order reflected light can be reduced in actual measurements.
第１図はこの発明による実施例の構成図、第２図は従来
の光ファイバ欠陥位置１１１１定番の構成図、
第３図は光ファイバ３の特性を表示器６に表示した一例
の波形図、
第４図は光ファイバ３の特性を表示器６に表示した他の
例の波形図、
第５図は到達時間測定手段９．１０の部分のフローチャ
ート。
１・・・・・・光パルス発生回路、２・・・・・・光ス
ィッチ、３・・・・・・光ファイバ、４・・・・・・Ｏ
／Ｅ変換回路、５・・・・・・Ａ／Ｄ変換回路、６・・
・・・・表示器、７・・・・・・近端、８・・・・・・
遠端、９・・・・・・到達時間測定手段、１０・・・・
・・到達時間１ｊ１１定手段、１１・・・・・・始端、
１２・・・・・・近端反射光、１３・・・・・・後方散
乱光、１４・・・・・・１次反射光、１５・・・・・・
２次反射光、１６・・・・・・破線マーカ、１７・・・
・・・２次反射光。
代理人 弁理−ト 小 俣 欽 ｉ°１第 １
図
第 ！ メFIG. 1 is a block diagram of an embodiment according to the present invention, FIG. 2 is a block diagram of a standard conventional optical fiber defect location 1111, and FIG. 3 is a waveform diagram of an example of the characteristics of the optical fiber 3 displayed on the display 6. FIG. 4 is a waveform diagram of another example in which the characteristics of the optical fiber 3 are displayed on the display 6, and FIG. 5 is a flowchart of the arrival time measuring means 9.10. 1... Optical pulse generation circuit, 2... Optical switch, 3... Optical fiber, 4... O
/E conversion circuit, 5...A/D conversion circuit, 6...
...Display unit, 7...Near end, 8...
Far end, 9... Arrival time measuring means, 10...
...Arrival time 1j11 constant means, 11...Start point,
12... Near end reflected light, 13... Backscattered light, 14... Primary reflected light, 15...
Secondary reflected light, 16...Dotted line marker, 17...
...Secondary reflected light. Agent Attorney Kin Omata i°1 1st
Figure number! Mail
Claims (1)
らの反射光を電気信号に変換し、前記信号を表示器に表
示させて前記光ファイバの欠陥位置を検出する光ファイ
バ欠陥位置測定器において、前記表示器上の始端から１
次反射光までの到達時間を測定する第１の到達時間測定
手段と、前記表示器上の始端から高次反射光までの到達
時間を測定する第２の到達時間測定手段とを備え、第１
の到達時間測定手段と第２の到達時間測定手段により、
前記表示器に現れる高次反射光の位置を演算で求め、前
記表示器上に高次反射光の位置を表示することを特徴と
する光ファイバ欠陥位置測定器の高次反射光識別方法。1. An optical fiber defect position measuring device that detects the defect position of the optical fiber by inputting a light pulse into an optical fiber, converting the reflected light from the optical fiber into an electrical signal, and displaying the signal on a display, 1 from the starting end on the display
a first arrival time measuring means for measuring the arrival time to the next reflected light; and a second arrival time measuring means for measuring the arrival time from the starting point on the display to the higher-order reflected light;
By the arrival time measuring means and the second arrival time measuring means,
A method for identifying high-order reflected light in an optical fiber defect position measuring device, characterized in that the position of the high-order reflected light appearing on the display is calculated and the position of the high-order reflected light is displayed on the display.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5648086A JPS62212543A (en) | 1986-03-14 | 1986-03-14 | Method for discriminating higher-order reflected light from optical fiber defect locating device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5648086A JPS62212543A (en) | 1986-03-14 | 1986-03-14 | Method for discriminating higher-order reflected light from optical fiber defect locating device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62212543A true JPS62212543A (en) | 1987-09-18 |
| JPH0262169B2 JPH0262169B2 (en) | 1990-12-25 |
Family
ID=13028257
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5648086A Granted JPS62212543A (en) | 1986-03-14 | 1986-03-14 | Method for discriminating higher-order reflected light from optical fiber defect locating device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS62212543A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0733893A2 (en) * | 1995-03-20 | 1996-09-25 | Tektronix, Inc. | Apparatus and method for displaying multiple sample spacing waveform segments |
-
1986
- 1986-03-14 JP JP5648086A patent/JPS62212543A/en active Granted
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0733893A2 (en) * | 1995-03-20 | 1996-09-25 | Tektronix, Inc. | Apparatus and method for displaying multiple sample spacing waveform segments |
| EP0733893A3 (en) * | 1995-03-20 | 1998-11-11 | Tektronix, Inc. | Apparatus and method for displaying multiple sample spacing waveform segments |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0262169B2 (en) | 1990-12-25 |
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