JPS6128236A - Optical signal reception circuit - Google Patents

Optical signal reception circuit

Info

Publication number
JPS6128236A
JPS6128236A JP14877284A JP14877284A JPS6128236A JP S6128236 A JPS6128236 A JP S6128236A JP 14877284 A JP14877284 A JP 14877284A JP 14877284 A JP14877284 A JP 14877284A JP S6128236 A JPS6128236 A JP S6128236A
Authority
JP
Japan
Prior art keywords
signal
optical signal
amplifier
period
converter
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
Application number
JP14877284A
Other languages
Japanese (ja)
Other versions
JPH0620190B2 (en
Inventor
Kazuto Takaso
高祖　一人
Yoichi Ogura
洋一 小倉
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Toshiba Corp
Original Assignee
Toshiba Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Toshiba Corp filed Critical Toshiba Corp
Priority to JP59148772A priority Critical patent/JPH0620190B2/en
Publication of JPS6128236A publication Critical patent/JPS6128236A/en
Publication of JPH0620190B2 publication Critical patent/JPH0620190B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/60—Receivers
    • H04B10/66—Non-coherent receivers, e.g. using direct detection
    • H04B10/69—Electrical arrangements in the receiver
    • H04B10/691—Arrangements for optimizing the photodetector in the receiver
    • H04B10/6911—Photodiode bias control, e.g. for compensating temperature variations

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Circuits Of Receivers In General (AREA)
  • Optical Communication System (AREA)
  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)

Abstract

PURPOSE:To receive stably an optical signal of burst form incoming periodically without distortion by detecting a mean value of a level of an optical signal incoming periodically at each period and using the mean value to adjust the bias potential of a DC eliminating capacitor to the optical signal received at the next period and the gain of the amplifier. CONSTITUTION:The optical signal PD of burst form is inputted to a photodiode 1 at each period T shown in a figure (a) for times T1-T3 shown in a figure (b) and the optical signal PD is converted into an electric signal by the photodiode 1. Succeedingly, a DA converter 12 converts the mean value of the optical signal at the period just before into an analog signal and the said analog signal is fed to a gain adjusting signal of the amplifier 3. Similarly, the DA converter 13 converts the mean value of the optical signal of the period just before into an analog signal and the said analog signal is fed as a bias potential signal of the capacitor 2 via a resistor 14. For example, the DA converter 12 outputs a gain adjusting signal having a level shown in a figure (e) inversely proportional to the mean value of the optical signal received at the period just before. Thus, the gain of the amplifier 3 is adjusted at each period T to stabilize the output signal.

Description

【発明の詳細な説明】 〔発明の技術分野〕 本発明は、複数の光信号発信装置から予め定められた順
序で周期的に発信されるバースト構成の光信号を受信す
る光信号受信回路に関するものである。[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an optical signal receiving circuit that receives burst-structured optical signals periodically transmitted in a predetermined order from a plurality of optical signal transmitting devices. It is.

〔発明の技術的背景〕[Technical background of the invention]

近年、ある限られた範囲内に複数のデータ処理装置を設
置し、各処理装置相互間では光信号によってデータの相
互通信を行うことＫより、データ処理の効率化を図るよ
うにしたローカルエリアネットワークシステムが実用化
されている。In recent years, local area networks have been developed to improve the efficiency of data processing by installing multiple data processing devices within a limited area and mutually communicating data between each processing device using optical signals. The system has been put into practical use.

このようなシステムにおいて、データ通信用の光信号は
Ｆ８に変調等の変調を受けてバースト構成の光信号とし
て発信され、しかも予め定められた順序で周期的に発信
される。In such a system, an optical signal for data communication undergoes modulation such as F8 modulation and is transmitted as a burst optical signal, and is periodically transmitted in a predetermined order.

そこで、このような光信号を受ける側の装置には、従来
、第３図または第４図に示すような光信号受信回路が用
いられていた。Therefore, an optical signal receiving circuit as shown in FIG. 3 or 4 has conventionally been used in a device receiving such an optical signal.

すなわち、第３図に示す光信号受信回路は光信号ＰＨを
フォトダイオードＩＫよって受け、このフォトダイオー
ド１の出力信号を直流成分除去用のコンデンサ２を介し
て増幅器３に入力し、増幅器３で増幅の後所要の回路部
に送出するものである。また、第４図に示す光信号受信
回路は、第３図の構成に対してピーク値検出回路４と直
流増幅器５を付加し、増幅器３の出力信号レベルのピー
クを検出し、このピーク値に応じて増幅器３の利得を直
流増幅器５によって調整し、増幅器３の出力信号レベル
をほぼ一定に保つように改良したものである。That is, the optical signal receiving circuit shown in FIG. 3 receives an optical signal PH through a photodiode IK, inputs the output signal of the photodiode 1 to an amplifier 3 via a capacitor 2 for removing DC components, and amplifies it. After that, it is sent to the required circuit section. The optical signal receiving circuit shown in FIG. 4 adds a peak value detection circuit 4 and a DC amplifier 5 to the configuration shown in FIG. Accordingly, the gain of the amplifier 3 is adjusted by the DC amplifier 5, and the output signal level of the amplifier 3 is kept almost constant.

〔背景技術の問題点〕[Problems with background technology]

ところ力ζ第３図および第４図に示す従来回路は、いず
れも増幅器３の入力に直流成分除去用のコンデンサ２が
接続されているため、複数の発信源から受ける光信号の
直流レベルに差がある場合。In both conventional circuits shown in Figures 3 and 4, a capacitor 2 for removing DC components is connected to the input of an amplifier 3, so there is no difference in the DC level of optical signals received from multiple sources. If there is.

異なる直流レベルの光信号を受けた時にコンデンサ２に
過渡電流が流れ、増幅器３の出力信号に歪みが生じると
いう問題がありた。また、増幅器３の利得を調整する第
４図の従来回路では、ピーク値検出回路４および直流増
幅器５の応答遅れのために、増幅器３の出力信号レベル
が安定するまでに時間を要し、特に発信源毎に光信号直
流レベルが異なる場合には増幅器３の出力信号を解読す
るのが困難になるという問題点があった。There is a problem in that when optical signals of different DC levels are received, a transient current flows through the capacitor 2, causing distortion in the output signal of the amplifier 3. Furthermore, in the conventional circuit shown in FIG. 4 that adjusts the gain of the amplifier 3, it takes time for the output signal level of the amplifier 3 to become stable due to the response delay of the peak value detection circuit 4 and the DC amplifier 5. There is a problem in that it becomes difficult to decipher the output signal of the amplifier 3 when the optical signal DC level differs depending on the source.

〔発明の目的〕[Purpose of the invention]

本発明は、上記のような問題点を解決し１周期的に到来
するバースト構成の光信号を歪みなく安定に受信できる
光信号受信回路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 optical signal receiving circuit that can solve the above-mentioned problems and stably receive burst-structured optical signals that arrive periodically without distortion.

〔発明の概要〕[Summary of the invention]

本発明は１周期的に到来する光信号のレベルの平均値を
各周期毎に検出し、この平均値により次の周期に受ける
光信号に対する直流除去用コンデンサのバイアス電位お
よび増幅器の利得を調整するように＃ｌ成したこと釦よ
り、上記の目的を達成している。The present invention detects the average value of the level of the optical signal that arrives in each period, and uses this average value to adjust the bias potential of the DC removal capacitor and the gain of the amplifier for the optical signal received in the next period. As shown in the #l button, the above purpose has been achieved.

〔発明の実施例〕[Embodiments of the invention]

以下、実施例に基づいて本発明の詳細な説明する。 Hereinafter, the present invention will be described in detail based on examples.

第１図は本発明の一実施例を示す回路図であり、フォト
ダイオード１には第２図（ａ）に示す周期Ｔ毎に第２図
（ｂ）に示すような時間Ｔ、、Ｔ、、’ｒ３のバースト
構成の光信号ＰＤが入力される。この光信号ＰＤはフォ
トダイオード１によって電気信号に変換されるが、この
フォトダイオード１の出力信号は従来と同様罠直流除去
用のコンデンサ２を介して増幅器３に入力される。また
同時に、バッファアンプ６を介して抵抗７とコンデンサ
８とから成る平均化回路圧入力され、その出力信号レベ
ルの平均値信号が形成される。これにより、第２図（ｂ
）　Ｋ示すようなレベルの光信号Ｐ　Ｈが到来した場合
には、第２図（Ｃ）に示すような平均値信号が形成され
る。FIG. 1 is a circuit diagram showing an embodiment of the present invention, in which the photodiode 1 is connected to the photodiode 1 for each period T shown in FIG. , 'r3 burst-configured optical signals PD are input. This optical signal PD is converted into an electric signal by a photodiode 1, and the output signal of the photodiode 1 is inputted to an amplifier 3 via a capacitor 2 for removing trap direct current, as in the conventional case. At the same time, the voltage is input to an averaging circuit consisting of a resistor 7 and a capacitor 8 via a buffer amplifier 6, and an average value signal of the output signal level is formed. As a result, Figure 2 (b
) When an optical signal PH of a level as shown by K arrives, an average value signal as shown in FIG. 2(C) is formed.

この平均値信号はＡＤ変換器９に入力され、タイミング
発生器１０から第２図（ａ）に示すように時間Ｔｎ（ｎ
＝１．２．３）の開始部分で発生されるタイミング信号
によりディジタル値に変換される。This average value signal is input to the AD converter 9, and from the timing generator 10, the time Tn(n
= 1.2.3) is converted into a digital value by a timing signal generated at the beginning.

そしてそのディジタル値はタイミング発生器１０から発
生される前記タイミング信号に同期したタイミングでメ
モリ１１に記憶される。The digital value is then stored in the memory 11 at a timing synchronized with the timing signal generated from the timing generator 10.

このメモリ１１に記憶されたディジタル値、すなわち光
信号の平均値は次の周期の光信号を受ける開始タイミン
グでタイミング発生器１０から発生されるタイミング信
号によって読出され、ＤＡ変換器１２および１３に供給
される。すると、ＴＥＡ変換器１２は直前の周期の光信
号の平均値をアナログ信号に変換し、このアナログ信号
を増幅器３の利得調整信号として供給する。同様に、Ｄ
Ａ変換器１３も直前の周期の光信号の平均値をアナログ
信号に変換し、このアナログ信号を抵抗１４を介してコ
ンデンサ２のバイアス電位信号として供給する。The digital value stored in this memory 11, that is, the average value of the optical signal, is read out by the timing signal generated from the timing generator 10 at the start timing of receiving the next cycle of the optical signal, and is supplied to the DA converters 12 and 13. be done. Then, the TEA converter 12 converts the average value of the optical signal of the immediately previous period into an analog signal, and supplies this analog signal as a gain adjustment signal to the amplifier 3. Similarly, D
The A converter 13 also converts the average value of the optical signal of the immediately preceding period into an analog signal, and supplies this analog signal as a bias potential signal to the capacitor 2 via the resistor 14.

例えば、ＤＡ変換器１２は直前の周期に受けた光信号の
平均値の大きさに反比例して第２図（ｅ）　Ｋ示すよう
なレベルの利得調整信号を出力する。これにより、増幅
器３の利得は周期Ｔ毎に調整され、その出力信号の安定
化が図られる。For example, the DA converter 12 outputs a gain adjustment signal having a level as shown in FIG. 2(e) K in inverse proportion to the average value of the optical signal received in the immediately preceding period. Thereby, the gain of the amplifier 3 is adjusted every cycle T, and the output signal thereof is stabilized.

一方、ＤＡ変換器１３も直前の周期に受けた光信号の平
均値の大きさに反比例してコンデンサ２のバイアス電位
を調整するための第２図（ｅ）と同様のバイアス電位信
号を出力する。これにより、光信号の直流レベルが変動
するために時間Ｔｎ　（ｎ　＝１．２．３）の境界でコ
ンデンサ２の出力に発生する第２図（ｄ）に示すような
過渡的な波形Ａは、バイアス電位の調整によって抑制さ
れる。この結果、増幅器３には第２図（ｆ）に示すよう
に直流レベルが一様に揃った信号が入力され、この増幅
器３からは利得調整と相乗効果により、第２図（ｇ）に
示すように交流成分のみの安定したレベＩしの信号が出
力されるようになる。On the other hand, the DA converter 13 also outputs a bias potential signal similar to that shown in FIG. 2(e) for adjusting the bias potential of the capacitor 2 in inverse proportion to the average value of the optical signal received in the previous cycle. . As a result, as the DC level of the optical signal fluctuates, the transient waveform A shown in FIG. , can be suppressed by adjusting the bias potential. As a result, a signal with a uniform DC level is input to the amplifier 3 as shown in FIG. 2(f), and the signal is output from the amplifier 3 as shown in FIG. 2(g) due to gain adjustment and synergistic effect. In this way, a stable signal with only the AC component at level I is output.

このように本実施例においては、周期的に到来する光信
号の直流レベルが異なる場合でも歪みのない安定したレ
ベルの光信号の受信出力を送出することかできる。また
、コンデンサ２のバイアス電位および増幅器３の利得を
バースト周期毎に調整しているため、従来のように利得
調整の応答遅れに起因する問題点も解消し得る。In this manner, in this embodiment, even if the DC levels of the periodically arriving optical signals are different, it is possible to send out the reception output of the optical signal at a stable level without distortion. Further, since the bias potential of the capacitor 2 and the gain of the amplifier 3 are adjusted every burst period, the problem caused by the delay in response in gain adjustment, which is conventional, can be solved.

なお、実施例におけるＤＡ変換器１２　、１．３は、と
もに前の周期の光信号の平均値に反比例した信号を出力
するものであるため、いずれか一方の出力信号を抵抗等
によって分割してコンデンサ２のバイアス電位および増
幅器３の利得調整信号として与えるようにすれば、他方
を省略することができる。Note that the DA converters 12 and 1.3 in the embodiment both output signals that are inversely proportional to the average value of the optical signals of the previous period, so the output signal of either one is divided by a resistor or the like. If it is provided as the bias potential of the capacitor 2 and the gain adjustment signal of the amplifier 3, the other can be omitted.

〔発明の効果〕〔Effect of the invention〕

以上の説明から明らかなように本発明によれば、周期的
に到来するバースト構成の光信号を６４のない安定した
レベルの受信出力として送１１することができ、事実上
受信信号のダイナミックレンジを拡大できるという効果
がある。従って、Ｎ個の光発信源から光信号を受けて通
信を行う各種の光通信システム等に適用すれば、極めて
優れた効果を発揮する。As is clear from the above description, according to the present invention, it is possible to transmit periodically arriving optical signals having a burst structure as a reception output of a stable level without 64, and in fact, the dynamic range of the reception signal can be reduced. It has the effect of being expandable. Therefore, if applied to various optical communication systems that perform communication by receiving optical signals from N optical transmission sources, extremely excellent effects will be exhibited.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は不発明の一実施例を示す回路図、第２図は第１
図の回路における各部出力波形を示す図。 第３図および第４図は従来の光信号受信回路の構成を示
す図である。 １・・・フォトダイオード、２・・・コンデンサ、３・
・・増幅器、８・・・コンデンサ、９・・・ＡＤ変換器
、１１・・・メモリ、１２．１３−・・ＤＡ変換器。Fig. 1 is a circuit diagram showing one embodiment of the invention, and Fig. 2 is a circuit diagram showing an embodiment of the invention.
FIG. 3 is a diagram showing output waveforms of each part in the circuit shown in the figure. FIGS. 3 and 4 are diagrams showing the configuration of a conventional optical signal receiving circuit. 1... Photodiode, 2... Capacitor, 3...
...Amplifier, 8...Capacitor, 9...AD converter, 11...Memory, 12.13-...DA converter.

Claims (1)

【特許請求の範囲】[Claims] バースト構成の光信号を所定周期で受ける受光素子と、
この受光素子の出力信号から直流成分を除去して増幅器
に入力するコンデンサと、前記受光素子の出力信号レベ
ルを平均化する平均化回路と、この平均化回路の出力信
号を前記所定周期でディジタル値に変換するＡＤ変換器
と、このＡＤ変換器から出力されるディジタル値を記憶
する記憶回路と、この記憶回路に記憶されたディジタル
値に基づき次の周期に受ける光信号に対する前記コンデ
ンサのバイアス電位および前記増幅器の利得を設定する
ＤＡ変換器とを備えて成る光信号受信回路。a light receiving element that receives a burst-configured optical signal at a predetermined period;
a capacitor that removes the DC component from the output signal of the light receiving element and inputs it to the amplifier; an averaging circuit that averages the output signal level of the light receiving element; and an averaging circuit that converts the output signal of the averaging circuit into a digital value at the predetermined period. an AD converter that converts the digital value into a digital value; a memory circuit that stores the digital value output from the AD converter; and a bias potential of the capacitor and the optical signal received in the next cycle based on the digital value stored in the memory circuit. An optical signal receiving circuit comprising: a DA converter for setting the gain of the amplifier.
JP59148772A 1984-07-18 1984-07-18 Optical signal receiving circuit Expired - Lifetime JPH0620190B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP59148772A JPH0620190B2 (en) 1984-07-18 1984-07-18 Optical signal receiving circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP59148772A JPH0620190B2 (en) 1984-07-18 1984-07-18 Optical signal receiving circuit

Publications (2)

Publication Number Publication Date
JPS6128236A true JPS6128236A (en) 1986-02-07
JPH0620190B2 JPH0620190B2 (en) 1994-03-16

Family

ID=15460315

Family Applications (1)

Application Number Title Priority Date Filing Date
JP59148772A Expired - Lifetime JPH0620190B2 (en) 1984-07-18 1984-07-18 Optical signal receiving circuit

Country Status (1)

Country Link
JP (1) JPH0620190B2 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0258934A (en) * 1988-08-25 1990-02-28 Toshiba Corp Automatic gain controlled amplifying circuit
US5737111A (en) * 1996-07-02 1998-04-07 Fujitsu Limited Optical receiving apparatus

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0258934A (en) * 1988-08-25 1990-02-28 Toshiba Corp Automatic gain controlled amplifying circuit
US5737111A (en) * 1996-07-02 1998-04-07 Fujitsu Limited Optical receiving apparatus

Also Published As

Publication number Publication date
JPH0620190B2 (en) 1994-03-16

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