JPH07123048A - Optical receiver - Google Patents
Optical receiverInfo
- Publication number
- JPH07123048A JPH07123048A JP5228837A JP22883793A JPH07123048A JP H07123048 A JPH07123048 A JP H07123048A JP 5228837 A JP5228837 A JP 5228837A JP 22883793 A JP22883793 A JP 22883793A JP H07123048 A JPH07123048 A JP H07123048A
- Authority
- JP
- Japan
- Prior art keywords
- stage amplifier
- photodiode
- pin diode
- output
- amplifier
- 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.)
- Pending
Links
Landscapes
- Electronic Switches (AREA)
- Optical Communication System (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、音声信号および映像信
号を周波数多重して伝送するアナログ光伝送装置におけ
る光受信装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical receiving device in an analog optical transmission device for frequency-multiplexing and transmitting an audio signal and a video signal.
【０００２】[0002]
【従来の技術】図３は従来の光受信装置の構成を示して
いる。図３において、１はフォトダイオードであり、２
はフォトダイオード１の負荷抵抗である。３はキャパシ
タンス、４は初段アンプ、５は可変減衰器、６はメイン
アンプである。７はＡＧＣ（Automatic Gain Control)
回路であり、メインアンプ６の出力をモニタして、可変
減衰器５の減衰量を制御する。2. Description of the Related Art FIG. 3 shows the configuration of a conventional optical receiver. In FIG. 3, 1 is a photodiode, and 2
Is the load resistance of the photodiode 1. Reference numeral 3 is a capacitance, 4 is a first stage amplifier, 5 is a variable attenuator, and 6 is a main amplifier. 7 is AGC (Automatic Gain Control)
The circuit monitors the output of the main amplifier 6 and controls the amount of attenuation of the variable attenuator 5.
【０００３】次に上記従来例における動作について説明
する。フォトダイオード１からの出力信号は、キャパシ
タンス３を介して初段アンプ４に接続され、可変減衰器
５を通ってメインアンプ６により増幅される。メインア
ンプ６の出力は、ＡＧＣ回路７によって監視され、ＡＧ
Ｃ回路７が、可変減衰器５の減衰量を、図２（ｂ）の破
線で示すように受光パワーに比例して増大するように制
御することにより、一定の出力レベルを得ている。Next, the operation of the above conventional example will be described. The output signal from the photodiode 1 is connected to the first stage amplifier 4 via the capacitance 3, passes through the variable attenuator 5, and is amplified by the main amplifier 6. The output of the main amplifier 6 is monitored by the AGC circuit 7,
The C circuit 7 controls the attenuation amount of the variable attenuator 5 so as to increase in proportion to the received light power as shown by the broken line in FIG. 2 (b), thereby obtaining a constant output level.
【０００４】このように、上記従来の光受信装置では、
ＡＧＣ回路７が可変減衰器５を制御することにより、受
光パワーが変化しても一定の出力を得ることができる。As described above, in the above conventional optical receiver,
Since the AGC circuit 7 controls the variable attenuator 5, it is possible to obtain a constant output even if the received light power changes.
【０００５】[0005]
【発明が解決しようとする課題】しかしながら、上記従
来の光受信装置では、大受光パワー時には、初段アンプ
４の出力レベルが過大となり、初段アンプ４により歪特
性が劣化するという問題があった。However, the above-mentioned conventional optical receiving device has a problem that the output level of the first-stage amplifier 4 becomes excessive at the time of high received light power and the distortion characteristic is deteriorated by the first-stage amplifier 4.
【０００６】また、初段アンプ４により発生する歪を制
御するために、初段アンプ４の前段に減衰器を挿入する
と、小受光パワー時にＣＮＲ（搬送波電力対雑音電力
比）特性が劣化するという問題があった。If an attenuator is inserted before the first-stage amplifier 4 in order to control the distortion generated by the first-stage amplifier 4, there is a problem that the CNR (carrier power to noise power ratio) characteristic is deteriorated at a small received power. there were.
【０００７】なお、初段アンプのインターセプトポイン
トを高くして、歪の劣化を抑制することも可能だが、こ
の場合には初段アンプにパワーアンプを用いる必要があ
り、ＮＦ（雑音指数）の劣化によるＣＮＲの劣化および
消費電力の増大という問題があった。It is possible to raise the intercept point of the first-stage amplifier to suppress the deterioration of distortion, but in this case, it is necessary to use a power amplifier for the first-stage amplifier, and CNR due to deterioration of NF (noise figure). There was a problem of deterioration of power consumption and increase of power consumption.
【０００８】本発明は、このような従来の問題を解決す
るものであり、広いダイナミックレンジにおいて、良好
な歪・ＣＮＲ特性を持つ光受信装置を提供することを目
的とするものである。The present invention solves such a conventional problem, and an object of the present invention is to provide an optical receiver having good distortion and CNR characteristics in a wide dynamic range.
【０００９】[0009]
【課題を解決するための手段】本発明は、上記目的を達
成するために、初段アンプの前段にフォトダイオードの
負荷抵抗と交流的に並列にｐｉｎダイオードを挿入し、
大受光パワー時にのみ初段アンプの入力レベルを減衰さ
せて初段アンプによる歪の劣化を抑制するようにしたも
のである。In order to achieve the above-mentioned object, the present invention inserts a pin diode in parallel with the load resistance of the photodiode in parallel with the load resistance of the photodiode in front of the first-stage amplifier,
The input level of the first-stage amplifier is attenuated only at the time of large received light power to suppress the distortion deterioration due to the first-stage amplifier.
【００１０】[0010]
【作用】したがって、本発明によれば、大受光パワー時
における初段アンプの歪特性の劣化を抑制することによ
り、歪特性の良好な光受信装置を実現することができ
る。Therefore, according to the present invention, it is possible to realize an optical receiving apparatus having a good distortion characteristic by suppressing the deterioration of the distortion characteristic of the first-stage amplifier at the time of high received light power.
【００１１】[0011]
【実施例】図１は本発明の一実施例の構成を示すもので
ある。図１において、１１はフォトダイオードであり、
１２はフォトダイオード１１の負荷抵抗である。１３は
キャパシタンス、１４は初段アンプ、１６はメインアン
プ、１７はＡＧＣ回路である。１８はｐｉｎダイオード
であり、キャパシタンス１９を介して負荷抵抗１２と並
列接続される。ＡＧＣ回路１７は、２つの出力を持ち、
一方の出力はｐｉｎダイオード１８に流す順電流を制御
し、他方の出力は可変減衰器１５の減衰量を制御する。DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the configuration of an embodiment of the present invention. In FIG. 1, 11 is a photodiode,
Reference numeral 12 is a load resistance of the photodiode 11. Reference numeral 13 is a capacitance, 14 is a first stage amplifier, 16 is a main amplifier, and 17 is an AGC circuit. Reference numeral 18 is a pin diode, which is connected in parallel with the load resistor 12 via a capacitance 19. The AGC circuit 17 has two outputs,
One output controls the forward current flowing through the pin diode 18, and the other output controls the attenuation amount of the variable attenuator 15.
【００１２】次に上記実施例における動作について説明
する。フォトダイオード１１からの出力信号は、キャパ
シタンス１３を介して初段アンプ１４に接続され、可変
減衰器１５を通ってメインアンプ１６から出力される。
ＡＧＣ回路１７は、メインアンプ１６の出力を監視し
て、受光パワーが増大した時にはｐｉｎダイオード１８
に流す順電流を増大させる。これによりｐｉｎダイオー
ド１８の抵抗成分が減少し、フォトダイオード１１の負
荷抵抗１２が等価的に減少するため、初段アンプ１４の
入力レベルＰO は、図２（ａ）に示すように、従来例の
レベル（破線）と比較して大受光パワー時に減衰する。
これと同時に可変減衰器１５の減衰量（ＡＴＴ）を図３
（ｂ）に示すように同様に減衰させることにより、光受
光装置の出力は一定に保たれる。このときのＣＮＲ特性
は、図３（ｃ）に示すように、従来例の特性（破線）と
殆ど差は生じない。また、歪に関しては、従来例では図
３（ｄ）の破線に示すように大受光パワー時に初段アン
プ１４で生じる歪が支配的になって大きく劣化するが、
本実施例では、大受光パワー時に初段アンプ１４の入力
が減衰するため、初段アンプ１４で発生する歪が抑制さ
れ、図３（ｄ）の実線に示すように改善される。Next, the operation of the above embodiment will be described. The output signal from the photodiode 11 is connected to the first-stage amplifier 14 via the capacitance 13, passes through the variable attenuator 15, and is output from the main amplifier 16.
The AGC circuit 17 monitors the output of the main amplifier 16, and when the received light power increases, the pin diode 18
To increase the forward current. As a result, the resistance component of the pin diode 18 is reduced and the load resistance 12 of the photodiode 11 is equivalently reduced, so that the input level P O of the first-stage amplifier 14 is the same as that of the conventional example as shown in FIG. Compared to the level (broken line), it attenuates when the received light power is large.
At the same time, the attenuation amount (ATT) of the variable attenuator 15 is shown in FIG.
By similarly attenuating as shown in (b), the output of the light receiving device is kept constant. As shown in FIG. 3C, the CNR characteristic at this time is almost the same as the characteristic (broken line) of the conventional example. Regarding the distortion, in the conventional example, as shown by the broken line in FIG. 3 (d), the distortion generated in the first-stage amplifier 14 at the time of large received light power becomes dominant and is greatly deteriorated.
In the present embodiment, the input of the first-stage amplifier 14 is attenuated when the received light power is large, so that the distortion generated in the first-stage amplifier 14 is suppressed, and the distortion is improved as shown by the solid line in FIG.
【００１３】このように、上記実施例によれば、大受光
パワー時にのみ、ｐｉｎダイオード１８に電流を流し
て、初段アンプ１４の入力レベルを減衰させるため、初
段アンプ１４による歪の劣化が抑制されるという効果を
有する。As described above, according to the above-described embodiment, the current is passed through the pin diode 18 and the input level of the first-stage amplifier 14 is attenuated only when the large light-receiving power is received. Has the effect of
【００１４】[0014]
【発明の効果】本発明は、上記実施例から明らかなよう
に、大受光パワー時には、初段アンプの前段で入力信号
を減衰させるため、初段アンプによる歪の劣化を抑制す
ることができ、また、小受光パワー時には、従来と同等
な動作をするため、ＣＮＲ特性の劣化を抑制することが
できるという効果を有する。As is apparent from the above-described embodiments, the present invention attenuates the input signal at the stage before the first-stage amplifier at the time of high received light power, so that the distortion of the first-stage amplifier can be prevented from being deteriorated. When the received light power is small, the same operation as that of the related art is performed, so that it is possible to suppress the deterioration of the CNR characteristics.
【図１】本発明の一実施例における光受信装置の構成を
示す概略ブロック図FIG. 1 is a schematic block diagram showing the configuration of an optical receiver according to an embodiment of the present invention.
【図２】（ａ）受光パワーに対する初段アンプ入力レベ
ルの関係を示す特性図 （ｂ）受光パワーに対する可変減衰器の減衰量の関係を
示す特性図 （ｃ）受光パワーに対するＣＮＲの関係を示す特性図 （ｄ）受光パワーに対する歪の関係を示す特性図FIG. 2A is a characteristic diagram showing the relationship between the received light power and the input level of the first-stage amplifier. FIG. 2B is a characteristic diagram showing the relationship between the received light power and the attenuation of the variable attenuator. FIG. 2C is a characteristic showing the relationship between the received light power and CNR. Figure (d) Characteristic diagram showing the relationship between the received light power and distortion
【図３】従来の光受信装置の構成を示す概略ブロック図FIG. 3 is a schematic block diagram showing a configuration of a conventional optical receiver.
１１ フォトダイオード １２ フォトダイオードの負荷抵抗 １３ キャパシタンス １４ 初段アンプ １５ 可変減衰器 １６ メインアンプ １７ ＡＧＣ回路 １８ ｐｉｎダイオード １９ キャパシタンス 11 Photodiode 12 Photodiode load resistance 13 Capacitance 14 First stage amplifier 15 Variable attenuator 16 Main amplifier 17 AGC circuit 18 Pin diode 19 Capacitance
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 ＦＩ 技術表示箇所 Ｈ０４Ｂ 10/28 10/26 10/14 10/04 10/06 ─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 6 Identification code Office reference number FI technical display location H04B 10/28 10/26 10/14 10/04 10/06
Claims (1)
ードと直列に接続された負荷抵抗と、前記負荷抵抗と交
流的に並列に挿入されたｐｉｎダイオードと、前記フォ
トダイオードの出力を増幅する初段アンプと、前記初段
アンプの出力を減衰させる可変減衰器と、前記可変減衰
器の出力を増幅するメインアンプと、前記メインアンプ
の出力を監視して前記可変減衰器およびｐｉｎダイオー
ドを制御するＡＧＣ回路とを備え、前記ＡＧＣ回路が、
大受光パワー時に前記ｐｉｎダイオードに順電流を流し
て、前記フォトダイオードの交流的な負荷抵抗を減少さ
せることにより前記初段アンプの入力電力を減衰させる
ことを特徴とする光受信装置。1. A photodiode, a load resistance connected in series with the photodiode, a pin diode inserted in parallel with the load resistance in alternating current, and a first stage amplifier for amplifying an output of the photodiode. A variable attenuator that attenuates the output of the first-stage amplifier, a main amplifier that amplifies the output of the variable attenuator, and an AGC circuit that monitors the output of the main amplifier and controls the variable attenuator and the pin diode. , The AGC circuit,
A light receiving device characterized in that a forward current is passed through the pin diode at the time of high light reception power to reduce an AC load resistance of the photodiode to attenuate input power of the first stage amplifier.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5228837A JPH07123048A (en) | 1993-09-14 | 1993-09-14 | Optical receiver |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5228837A JPH07123048A (en) | 1993-09-14 | 1993-09-14 | Optical receiver |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH07123048A true JPH07123048A (en) | 1995-05-12 |
Family
ID=16882641
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5228837A Pending JPH07123048A (en) | 1993-09-14 | 1993-09-14 | Optical receiver |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07123048A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19547603A1 (en) * | 1995-12-20 | 1997-06-26 | Sel Alcatel Ag | Optical amplifier device |
| EP1990657A1 (en) | 2007-05-07 | 2008-11-12 | Sick Ag | Optical rangefinder |
-
1993
- 1993-09-14 JP JP5228837A patent/JPH07123048A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19547603A1 (en) * | 1995-12-20 | 1997-06-26 | Sel Alcatel Ag | Optical amplifier device |
| EP1990657A1 (en) | 2007-05-07 | 2008-11-12 | Sick Ag | Optical rangefinder |
| EP1990656A1 (en) * | 2007-05-07 | 2008-11-12 | Sick Ag | Attenuator with PIN diodes for optical rangefinder |
| US7859651B2 (en) | 2007-05-07 | 2010-12-28 | Sick Ag | Optical range finder |
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