JPH0831823B2 - Optical reception level monitor circuit - Google Patents
Optical reception level monitor circuitInfo
- Publication number
- JPH0831823B2 JPH0831823B2 JP62081712A JP8171287A JPH0831823B2 JP H0831823 B2 JPH0831823 B2 JP H0831823B2 JP 62081712 A JP62081712 A JP 62081712A JP 8171287 A JP8171287 A JP 8171287A JP H0831823 B2 JPH0831823 B2 JP H0831823B2
- Authority
- JP
- Japan
- Prior art keywords
- reception level
- operational amplifier
- optical reception
- optical
- monitor circuit
- 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.)
- Expired - Lifetime
Links
Description
【発明の詳細な説明】 〔産業上の利用分野〕 この発明は，光受信器の光受信レベルをモニタする光
受信レベルモニタ回路の改良に関するものである。TECHNICAL FIELD The present invention relates to an improvement of an optical reception level monitor circuit for monitoring the optical reception level of an optical receiver.
〔従来の技術〕 光受信器の光受信レベルをモニタする光受信レベルモ
ニタ回路としては，光信号を電気信号に変換した後の振
幅又はピーク値を検出する方法と，光信号の平均値を電
気信号に変換して検出する方法が考えられる。簡易形の
光受信器では，構成が簡単である光信号の平均値を電気
信号に変換して検出する方法がよく用いられる。[Prior Art] An optical reception level monitor circuit for monitoring the optical reception level of an optical receiver includes a method of detecting an amplitude or a peak value after converting an optical signal into an electrical signal, and an average value of the optical signal as an electrical signal. A method of converting into a signal and detecting the signal can be considered. In a simple optical receiver, a method of converting an average value of an optical signal into an electric signal and detecting the electric signal is often used because of its simple structure.
従来，光信号の平均値を電気信号に変換して検出する
光受信レベルモニタ回路の構成の一例として，第３図に
示す回路がよく知られている。第３図において，（１）
は光信号を電気信号に変換する受光素子，（２），
（３），（５）は抵抗，（４）はコンデンサ，（６）は
演算増幅器，（７）は基準電圧源，（８）は比較器，
（９）はコンデンサ，（10）は増幅器である。Conventionally, the circuit shown in FIG. 3 is well known as an example of the configuration of an optical reception level monitor circuit that detects the average value of an optical signal by converting it into an electric signal. In Figure 3, (1)
Is a light receiving element for converting an optical signal into an electric signal, (2),
(3) and (5) are resistors, (4) is a capacitor, (6) is an operational amplifier, (7) is a reference voltage source, (8) is a comparator,
(9) is a capacitor and (10) is an amplifier.
従来の光受信レベルモニタ回路は，上記のように構成
されていて，受光素子（１）に入力した光信号は受光素
子（１）によって電流信号に変換され，抵抗（２）によ
って電圧信号に変換される。電圧信号は演算増幅器
（６）によって抵抗（３）の抵抗値に対する抵抗（５）
の抵抗値に比例して増幅される。増幅されるとき，電圧
信号はコンデンサ（４）によって平均され，演算増幅器
（６）の出力には光信号の平均値に比例した電圧が出力
される。基準電圧源（７）の電圧を所定の光受信レベル
に相当する電圧に設定すれば，演算増幅器（６）の出力
電圧と基準電圧源（７）の電圧が比較器（８）によって
比較され，その大小関係により比較器（８）の出力状態
が変化する。つまり，所定の光が受信されているか否か
をモニタすることができる。なお，交流成分はコンデン
サ（９）を介して増幅器（10）に入力され増幅される。The conventional optical reception level monitor circuit is configured as described above, and the optical signal input to the light receiving element (1) is converted into a current signal by the light receiving element (1) and converted into a voltage signal by the resistor (2). To be done. The voltage signal is supplied to the resistance (5) corresponding to the resistance value of the resistance (3) by the operational amplifier (6).
It is amplified in proportion to the resistance value of. When amplified, the voltage signal is averaged by the capacitor (4), and a voltage proportional to the average value of the optical signal is output to the output of the operational amplifier (6). If the voltage of the reference voltage source (7) is set to a voltage corresponding to a predetermined optical reception level, the output voltage of the operational amplifier (6) and the voltage of the reference voltage source (7) are compared by the comparator (8), The output state of the comparator (8) changes depending on the magnitude relationship. That is, it is possible to monitor whether or not the predetermined light is received. The AC component is input to and amplified by the amplifier (10) via the capacitor (9).
上記のような従来の光受信レベルモニタ回路において
は，抵抗（３）の抵抗値をR3，抵抗（５）の抵抗値を
R5，演算増幅器（６）の入力オフセット電圧をVoffとす
ると受光素子（１）の光受信レベルが非常に低い，ある
いは光入力がない場合，演算増幅器（６）の出力にはR5
／R3Voffなるオフセット電圧が現われる。In the conventional optical reception level monitor circuit as described above, the resistance value of the resistor (3) is R 3 , and the resistance value of the resistor (5) is
R 5 and the input offset voltage of the operational amplifier (6) are Voff, if the light receiving level of the light receiving element (1) is very low or there is no optical input, the output of the operational amplifier (6) will be R 5
An offset voltage of / R 3 Voff appears.
であるため出力オフセット電圧が大きくなり，光受信レ
ベルモニタ回路が正確な光受信レベルをモニタできな
い，あるいは誤動作するという問題があった。 Therefore, there is a problem that the output offset voltage becomes large and the optical reception level monitor circuit cannot monitor the accurate optical reception level or malfunctions.
この発明は，上記に示す問題点を解決するためになさ
れたもので，出力オフセット電圧を非常に小さくするこ
とにより，誤動作が少なく正確な光受信レベルがモニタ
できるモニタ回路を得ることを目的とする。The present invention has been made to solve the above-mentioned problems, and an object thereof is to obtain a monitor circuit which can monitor an accurate optical reception level with few malfunctions by making the output offset voltage very small. .
〔聞題点を解決するための手段〕 この発明による光受信レベルモニタ回路は受光素子と
演算増幅器の負入力端子間に抵抗を接続し，さらに，演
算増幅器の負入力端子と出力端子間に抵抗と定電圧ダイ
オードを並列接続したものである。[Means for Solving the Problems] In the optical reception level monitor circuit according to the present invention, a resistor is connected between the light receiving element and the negative input terminal of the operational amplifier, and further a resistor is provided between the negative input terminal and the output terminal of the operational amplifier. And a constant voltage diode are connected in parallel.
この発明における光受信レベルモニタ回路は，演算増
幅器の入力から見た場合，抵抗と受光素子が直列に接続
されているため，電圧増幅度が小さく，演算増幅器の出
力オフセット電圧が非常に小さくなる。In the optical reception level monitor circuit according to the present invention, when viewed from the input of the operational amplifier, the resistance and the light receiving element are connected in series, so that the voltage amplification degree is small and the output offset voltage of the operational amplifier is very small.
第１図はこの発明の一実施例の構成を示す図であり，
（１）は受光素子，（３）は抵抗，（４）はコンデン
サ，（５）は抵抗，（６）は演算増幅器，（７）は基準
電圧源，（８）は比較器，（９）はコンデンサ，（10）
は増幅器，（11）は定電圧ダイオードである。FIG. 1 is a diagram showing a configuration of an embodiment of the present invention,
(1) is a light receiving element, (3) is a resistor, (4) is a capacitor, (5) is a resistor, (6) is an operational amplifier, (7) is a reference voltage source, (8) is a comparator, and (9). Is a capacitor, (10)
Is an amplifier and (11) is a constant voltage diode.
上記のように構成された光受信レベルモニタ回路にお
いて，受光素子（１）により光信号が電流信号に変換さ
れ抵抗（３）とコンデンサ（４）により平均化される。
平均化された電流をIdとすると演算増幅器（６）の出力
電圧V1は次式で示される。In the optical reception level monitor circuit configured as described above, an optical signal is converted into a current signal by the light receiving element (1) and averaged by the resistor (3) and the capacitor (4).
Letting Id be the averaged current, the output voltage V 1 of the operational amplifier (6) is expressed by the following equation.
ただし R5：抵抗（５）の抵抗値 RZD：定電圧ダイオード（11）の等化抵抗値 光受信レベルが低い場合，つまりV1が小さい場合はRZD
≫１であるため V1Id・R5……（２） となる。 However, R 5 : Resistance value of the resistor (5) R ZD : Equalization resistance value of the constant voltage diode (11) When the optical reception level is low, that is, when V 1 is small, R ZD
>> Because it is 1 , it becomes V 1 Id ・ R 5 (2).
次に出力オフセット電圧V2を求めると次のようにな
る。Next, the output offset voltage V 2 is calculated as follows.
ただしVoff:演算増幅器（６）の入力オフセット電圧 RD：受光素子（１）の等価抵抗値 R3：抵抗（３）の抵抗値 光受信レベルが低い場合，RZD≫1,RD≫１であるため となり出力オフセット電圧は入力オフセット電圧と同程
度となり，通常の演算増幅器においては,Voff数mVで
あるため出力オフセット電圧が非常に小さくなる。 However, Voff: Input offset voltage of operational amplifier (6) R D : Equivalent resistance value of light receiving element (1) R 3 : Resistance value of resistor (3) When optical reception level is low, R ZD >> 1, R D >> 1 Because The output offset voltage is almost the same as the input offset voltage, and in an ordinary operational amplifier, the output offset voltage is very small because it is Voff several mV.
演算増幅器（６）の出力電圧は比較器（８）により基
準電圧源（７）と比較されるため，比較器（８）の出力
状態により，所定の光受信レベルの光が受信されている
か否かモニタすることができる。光受信レベルが高い場
合は第（１）式において，RZD≪R5となるため V1Id・R5……（５） となり，このときV1は定電圧ダイオード（11）の定電圧
値とほぼ同じ値となる。このため，演算増幅器（６）は
飽和せず演算増幅器（６）の負入力端子はほぼ零電位に
保持される。なお，入力した光信号のうち，交流成分は
抵抗（３）により電圧信号に変換されコンデンサ（９）
を介して増幅器（10）に入力され増幅される。Since the output voltage of the operational amplifier (6) is compared with the reference voltage source (7) by the comparator (8), whether the light of a predetermined optical reception level is received or not is determined by the output state of the comparator (8). Can be monitored. When the optical reception level is high, R ZD << R 5 in equation (1), so V 1 Id · R 5 (5), and V 1 is the constant voltage value of the constant voltage diode (11). Is almost the same value as. Therefore, the operational amplifier (6) is not saturated, and the negative input terminal of the operational amplifier (6) is held at substantially zero potential. The AC component of the input optical signal is converted into a voltage signal by the resistor (3) and is converted into a capacitor (9).
Is input to and amplified by the amplifier (10).
第２図はこの発明の他の実施例の構成を示す図であり
（１），（３）〜（11）は第１図に示すものと同じであ
る。動作については，第２図と比較すると受光素子
（１）の接続が逆であるため，信号の極性が逆になり，
定電圧ダイオード（11）と基準電圧源（７）の接続が逆
となることを除けば第２図と全く同じである。FIG. 2 is a diagram showing the configuration of another embodiment of the present invention, and (1), (3) to (11) are the same as those shown in FIG. Regarding the operation, compared with FIG. 2, the connection of the light receiving element (1) is reversed, so the polarity of the signal is reversed,
It is exactly the same as FIG. 2 except that the connection between the constant voltage diode (11) and the reference voltage source (7) is reversed.
〔発明の効果〕 以上のように，この発明によれば，受光素子と演算増
幅器の間に抵抗を接続しているため，演算増幅器の出力
オフセット電圧が非常に小さくなり，誤動作が少なく正
確な光受信レベルがモニタできる光受信レベルモニタ回
路が得られる効果がある。[Effects of the Invention] As described above, according to the present invention, since the resistor is connected between the light receiving element and the operational amplifier, the output offset voltage of the operational amplifier becomes very small, and there is little malfunction and accurate optical output. There is an effect that an optical reception level monitor circuit capable of monitoring the reception level can be obtained.
さらに加えて，演算増幅器の負入力端子と出力端子間
に抵抗と定電圧ダイオードを並列接続しているため，演
算増幅器が飽和せず，広い光受信レベル範囲で正確な動
作をする光受信レベルモニタ回路が得られる効果があ
る。In addition, since a resistor and a constant voltage diode are connected in parallel between the negative input terminal and output terminal of the operational amplifier, the operational amplifier does not saturate and the optical reception level monitor operates accurately in a wide optical reception level range. There is an effect that a circuit can be obtained.
第１図はこの発明の一実施例による光受信レベルモニタ
回路の構成を示す図，第２図はこの発明の他の実施例に
よる光受信レベルモニタ回路の構成を示す図，第３図は
従来の光受信レベルモニタ回路の構成を示す図である。 図において，（１）は受光素子，（２），（３），
（５）は抵抗，（４），（９）はコンデンサ，（６）は
演算増幅器，（７）は基準電圧源，（８）は比較器，
（10）は増幅器である。 なお，図中，同一符号は同一または相当部分を示す。FIG. 1 is a diagram showing a configuration of an optical reception level monitor circuit according to an embodiment of the present invention, FIG. 2 is a diagram showing a configuration of an optical reception level monitor circuit according to another embodiment of the present invention, and FIG. It is a figure which shows the structure of the optical reception level monitor circuit of. In the figure, (1) is a light receiving element, (2), (3),
(5) is a resistor, (4) and (9) are capacitors, (6) is an operational amplifier, (7) is a reference voltage source, (8) is a comparator,
(10) is an amplifier. In the drawings, the same reference numerals indicate the same or corresponding parts.
Claims (1)
受信レベルをモニタする光受信レベルモニタ回路におい
て、光信号を電気信号に変換する受光素子と、この光受
素子の出力を増幅する演算増幅器と、上記受光素子と演
算増幅器の負入力端子に接続された抵抗と、上記演算増
幅器の負入力端子と出力端子間に並列接続された抵抗と
定電圧ダイオードと、基準電圧源と、上記演算増幅器の
出力電圧と上記基準電圧源の電圧を比較する比較器とを
具備したことを特徴とする光受信レベルモニタ回路。1. An optical reception level monitor circuit for monitoring an optical reception level of an optical receiver for converting an optical signal into an electric signal, and a light receiving element for converting the optical signal into an electric signal, and an output of the light receiving element is amplified. An operational amplifier, a resistor connected to the negative input terminal of the light receiving element and the operational amplifier, a resistor and a constant voltage diode connected in parallel between the negative input terminal and the output terminal of the operational amplifier, a reference voltage source, An optical reception level monitor circuit comprising: a comparator for comparing the output voltage of the operational amplifier with the voltage of the reference voltage source.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62081712A JPH0831823B2 (en) | 1987-04-02 | 1987-04-02 | Optical reception level monitor circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62081712A JPH0831823B2 (en) | 1987-04-02 | 1987-04-02 | Optical reception level monitor circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63246942A JPS63246942A (en) | 1988-10-13 |
| JPH0831823B2 true JPH0831823B2 (en) | 1996-03-27 |
Family
ID=13754006
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62081712A Expired - Lifetime JPH0831823B2 (en) | 1987-04-02 | 1987-04-02 | Optical reception level monitor circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0831823B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0771717B2 (en) * | 1990-03-26 | 1995-08-02 | 本田技研工業株式会社 | Engine valve manufacturing method |
-
1987
- 1987-04-02 JP JP62081712A patent/JPH0831823B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63246942A (en) | 1988-10-13 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JPH1114663A (en) | Sensor for physical quantity | |
| US3024658A (en) | Measuring system | |
| JPH0831823B2 (en) | Optical reception level monitor circuit | |
| JPH09329628A (en) | Hall element type current detector | |
| JP2558691B2 (en) | AC light component amplifier | |
| JP2543612B2 (en) | Light receiving device | |
| US4612438A (en) | Light intensity sensor providing a variable output current | |
| US4176393A (en) | A.C. to D.C. voltage converter | |
| SU1583994A1 (en) | Device for measuring pressure in vacuum electronic device | |
| JP2769911B2 (en) | Pressure sensing circuit | |
| JPH0749538Y2 (en) | Electronic load device | |
| JP2918738B2 (en) | Photoelectric conversion circuit for distance measuring device | |
| SU1649462A1 (en) | Rectified sinusoidal voltage amplitude value extractor | |
| JPS6142239Y2 (en) | ||
| JPH0611482Y2 (en) | Peak detection circuit | |
| JP2700500B2 (en) | Pressure detection circuit | |
| JPH0690237B2 (en) | Peak value detection circuit | |
| JPH0251144B2 (en) | ||
| JP2530856Y2 (en) | Electromagnetic flow meter | |
| SU1018044A1 (en) | Electric radio component parameter automatic measuring device | |
| JPS5812141Y2 (en) | AC signal peak level detection circuit | |
| RU2024885C1 (en) | Device for measuring conductance | |
| JPH08500182A (en) | Level measuring device | |
| JPS5852543Y2 (en) | Poor contact detection device | |
| JPH0695120B2 (en) | Electronic component measuring device |