JPH05244027A - Receiver using optical transmission system - Google Patents
Receiver using optical transmission systemInfo
- Publication number
- JPH05244027A JPH05244027A JP4044224A JP4422492A JPH05244027A JP H05244027 A JPH05244027 A JP H05244027A JP 4044224 A JP4044224 A JP 4044224A JP 4422492 A JP4422492 A JP 4422492A JP H05244027 A JPH05244027 A JP H05244027A
- Authority
- JP
- Japan
- Prior art keywords
- optical transmission
- signal
- input
- optical transmitter
- transmission device
- 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.)
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- Noise Elimination (AREA)
- Radio Relay Systems (AREA)
- Optical Communication System (AREA)
- Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は光伝送方式を用いた受信
装置に関し，特に人工衛星などの飛翔体を追跡し，テレ
メータ情報等を受信復調する場合に，ＩＦ帯の信号を光
伝送方式によって伝送する光伝送方式を用いた受信装置
に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiver using an optical transmission system, and particularly when tracking a flying object such as an artificial satellite and receiving and demodulating telemeter information etc., an IF band signal is transmitted by the optical transmission system. The present invention relates to a receiver using an optical transmission method for transmitting.
【０００２】[0002]
【従来の技術】従来，この種の受信装置では，アンテ
ナ，低雑音増幅部，受信周波数変換部で構成されるＲＦ
部から，周波数変換後のＩＦ信号を受信復調部へ接続す
る際に，この間の距離が数百ｍ以上ある場合には，ケー
ブル損失および温度特性の問題，また雷対策等の理由か
ら光伝送方式が採用されている。2. Description of the Related Art Conventionally, in this type of receiving apparatus, an RF including an antenna, a low noise amplifying section, and a receiving frequency converting section is used.
When connecting the IF signal after frequency conversion to the receiving and demodulating section from the cable section, if the distance between them is several hundred meters or more, the optical transmission system may be used due to problems such as cable loss and temperature characteristics, and lightning countermeasures. Has been adopted.
【０００３】図３に，従来の光伝送方式を用いた受信装
置の一例を示す。FIG. 3 shows an example of a receiver using the conventional optical transmission system.
【０００４】図３において，受信入力端から入力された
ＲＦ信号は，低雑音増幅装置１で増幅された後，受信周
波数変換装置２によってＩＦ信号に周波数変換される。In FIG. 3, the RF signal input from the reception input terminal is amplified by the low noise amplifier 1 and then frequency-converted into an IF signal by the reception frequency converter 2.
【０００５】このＩＦ信号は，光伝送装置（送信部）４
によって光信号に変換され，光ファイバ等の光伝送路８
によって離れた位置まで伝送される。This IF signal is transmitted to the optical transmission device (transmission unit) 4
Is converted into an optical signal by the optical transmission line 8 such as an optical fiber.
Transmitted to a remote location.
【０００６】伝送された光信号は光伝送装置（受信部）
５で受信されて電気信号に変換され，変換された信号は
受信復調部６によって復調される。The transmitted optical signal is an optical transmission device (reception unit).
The signal is received at 5 and converted into an electric signal, and the converted signal is demodulated by the reception demodulation unit 6.
【０００７】このように，光伝送装置を用いる受信装置
では，光伝送装置（送信部）４から発生する雑音がシス
テム雑音を決定し，この雑音によりシステム雑音温度の
劣化を招く為，低スレッショルドレベルの受信装置には
用いられず，また光伝送装置（送信部）４の入力レベル
規定があって上限レベルを決定している為に，受信入力
端でのダイナミックレンジが狭いなどの制約がある上で
用いられている。As described above, in the receiver using the optical transmission device, the noise generated from the optical transmission device (transmitter) 4 determines the system noise, and this noise causes the deterioration of the system noise temperature. Is not used for the receiving device and the upper limit level is determined by the input level regulation of the optical transmission device (transmitting unit) 4, so that there is a constraint such as a narrow dynamic range at the receiving input end. Used in.
【０００８】上述したシステム雑音温度の劣化と，ダイ
ナミックレンジの制約について，図４を参照して説明す
る。The above-mentioned deterioration of the system noise temperature and the restriction of the dynamic range will be described with reference to FIG.
【０００９】いま，図４に示す如く，ＲＦ部を構成する
低雑音増幅装置１と受信周波数変換装置２による利得が
５０ｄＢに設定されているとする。Now, as shown in FIG. 4, it is assumed that the gain by the low noise amplifying apparatus 1 and the receiving frequency converting apparatus 2 which constitute the RF section is set to 50 dB.
【００１０】光伝送装置（送信部）４は，光通信におい
て要求される入力特性から，入力端でのＣ／Ｎが４５ｄ
Ｂ以上，かつ入力レベルは−２０ｄＢｍ以下と規定され
ている。The optical transmission device (transmitter) 4 has a C / N of 45d at the input end because of the input characteristics required in optical communication.
It is specified that the input level is B or higher and the input level is -20 dBm or lower.
【００１１】帯域幅が１０ＭＨｚであるとすると，光伝
送装置（送信部）４の入力で許容される雑音レベルは，
−２０−４５＝−６５（ｄＢｍ）で，さらに１Ｈｚ当り
に換算すると，−６５−７０＝−１３５（ｄＢｍ）以下
とすることが必要となる。Assuming that the bandwidth is 10 MHz, the allowable noise level at the input of the optical transmission device (transmitting section) 4 is
It is −20−45 = −65 (dBm), and when converted into 1 Hz, it is necessary to be −65−70 = −135 (dBm) or less.
【００１２】これらにもとづき，常温２０℃における光
伝送装置（送信部）４の入力で発生する雑音温度を求め
ると，ＴOPT ＝６３．６ｄＢＫ，すなわち２．２９０．
８６８Ｋとなる。Based on these, when the noise temperature generated at the input of the optical transmission device (transmission unit) 4 at room temperature of 20 ° C. is calculated, T OPT = 63.6 dBK, that is, 2.290.
It becomes 868K.
【００１３】従って，低雑音増幅装置１の入力側の受信
入力端での換算では，雑音温度ＴSOPT＝２２．９Ｋとな
る。Therefore, the noise temperature T SOPT = 22.9K when converted at the receiving input end on the input side of the low noise amplifier 1.
【００１４】このことは，ＴOPT ＝６３．６ｄＢＫの光
伝送装置（送信部）４により，受信入力端でＴSOPT＝２
２．９度の雑音温度劣化を等価的にもたらすことを意味
する。This means that T SOPT = 2 at the receiving input end by the optical transmission device (transmitting unit) 4 with T OPT = 63.6 dBK.
This means equivalently causing a noise temperature deterioration of 2.9 degrees.
【００１５】[0015]
【発明が解決しようとする課題】上述した従来の光伝送
方式を用いた受信装置では，図４に示す光伝送装置（送
信部）４で発生する雑音によって，受信入力端での雑音
温度の劣化量が２２．９Ｋとなり，受信系のシステム雑
音温度の劣化を招き，また光伝送装置（送信部）３の入
力端でのレベルが−２０ｄＢｍ以下という制約があるた
めに，受信入力端でのダイナミックレンジが大きくでき
ないという問題点がある。In the receiver using the above-mentioned conventional optical transmission system, the noise temperature at the receiving input end is deteriorated by the noise generated in the optical transmitter (transmitter) 4 shown in FIG. The amount becomes 22.9K, which causes deterioration of the system noise temperature of the receiving system, and the level at the input end of the optical transmission device (transmitting unit) 3 is -20 dBm or less. There is a problem that the range cannot be increased.
【００１６】本発明の目的は上述した問題点を解決し，
受信系のシステム雑音温度の劣化を著しく抑圧し，かつ
受信入力端でのダイナミックレンジの制約を大幅に緩和
しうる光伝送方式を用いた受信装置を提供することにあ
る。The object of the present invention is to solve the above-mentioned problems,
It is an object of the present invention to provide a receiver using an optical transmission system capable of significantly suppressing the deterioration of the system noise temperature of the receiving system and relieving the restriction of the dynamic range at the receiving input end significantly.
【００１７】[0017]
【課題を解決するための手段】本発明の受信装置は，人
工衛星などの飛翔体を追跡し，前記飛翔体の発するテレ
メータ情報を受けて受信復調する場合に，入力ＲＦ信号
を変換したＩＦ信号を光伝送装置によって伝送する光伝
送方式を用いた受信装置において，前記光伝送装置の送
信部の入力側に前記ＩＦ信号をステップ的に減衰させる
ステップ減衰器を設け，前記ステップ減衰器を入力ＲＦ
信号の強弱に応じて切り替えて受信入力端から前記光伝
送装置の送信入力までの利得を変化させ，前記光伝送装
置の送信部で発生する雑音によるシステム雑音温度の劣
化を抑圧し，かつ受信入力端でのダイナミックレンジを
拡大する構成を有する。The receiving apparatus of the present invention tracks an flying object such as an artificial satellite, and receives and demodulates the telemeter information emitted by the flying object to receive and demodulate the input RF signal. In a receiver using an optical transmission method for transmitting a signal by an optical transmission device, a step attenuator for stepwise attenuating the IF signal is provided at an input side of a transmitter of the optical transmission device, and the step attenuator is used as an input RF.
The gain from the reception input end to the transmission input of the optical transmission device is changed by switching according to the strength of the signal to suppress the deterioration of the system noise temperature due to the noise generated in the transmission part of the optical transmission device, and the reception input It has a structure to expand the dynamic range at the edge.
【００１８】[0018]
【実施例】次に，本発明について図面を参照して説明す
る。DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.
【００１９】図１は，本発明の一実施例の構成を示すブ
ロック図である。FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.
【００２０】図１に示す実施例は，ＲＦ部を構成する低
雑音増幅装置１および受信周波数変換装置２と，受信系
の利得をステップ的に減衰させるステップ減衰器３と，
光伝送系を構成する光伝送装置（送信部）４および光伝
送装置（受信部）５と，受信信号を復調し，かつ入力レ
ベルに対応したＡＧＣ電圧を出力する受信復調部６ａ
と，ＡＧＣ電圧にもとづいてステップ減衰器３のオン／
オフを制御する制御出力を送出するコンパレータ７とを
備えて成る。The embodiment shown in FIG. 1 includes a low noise amplifying apparatus 1 and a receiving frequency converting apparatus 2 which constitute an RF section, a step attenuator 3 for stepwise attenuating the gain of a receiving system,
An optical transmission device (transmission unit) 4 and an optical transmission device (reception unit) 5 that form an optical transmission system, and a reception demodulation unit 6a that demodulates a reception signal and outputs an AGC voltage corresponding to an input level.
And the step attenuator 3 is turned on / off based on the AGC voltage.
And a comparator 7 which outputs a control output for controlling the off state.
【００２１】次に，本実施例の動作について説明する。Next, the operation of this embodiment will be described.
【００２２】信号入力端から入力したＲＦ信号は，低雑
音増幅装置１で増幅され，受信周波数変換装置２によっ
てＩＦ信号に周波数変換される。このＩＦ信号はステッ
プ減衰器３を通り，光伝送装置（送信部）４に入力さ
れ，光信号として光ファイバで構成される光伝送路７に
て伝送される。The RF signal input from the signal input terminal is amplified by the low noise amplifier 1 and frequency-converted by the reception frequency converter 2 into an IF signal. The IF signal passes through the step attenuator 3 and is input to the optical transmission device (transmission unit) 4 and is transmitted as an optical signal through the optical transmission line 7 formed of an optical fiber.
【００２３】伝送された光信号は，光伝送装置（受信
部）５により受信され，電気信号に変換されるこの電気
信号は，受信復調部６において復調される。The transmitted optical signal is received by the optical transmission device (reception unit) 5, and this electric signal converted into an electric signal is demodulated by the reception demodulation unit 6.
【００２４】ステップ減衰器３は，入力したＩＦ信号の
レベルを０ｄＢ／２０ｄＢにステップ切り替えを行な
い，その切替を実行する制御信号は，受信復調部６が，
入力レベルに対応して発生し，出力するＡＧＣ電圧をコ
ンパレータ８によって比較，出力し，ステップ減衰器３
を自動制御する。The step attenuator 3 carries out step switching of the level of the input IF signal to 0 dB / 20 dB, and the control signal for executing the switching is received by the reception demodulation section 6.
The AGC voltage generated and output according to the input level is compared and output by the comparator 8, and the step attenuator 3
Control automatically.
【００２５】すなわち，受信信号レベルが−９０ｄＢｍ
と−７０ｄＢｍの間にあって所定の−９０ｄＢｍよりも
大きいときには，ステップ減衰器３をオンとして，２０
ｄＢの減衰レベルを与え，受信入力端から光伝送装置
（送信部）４までの非減衰時の利得７０ｄＢを５０ｄＢ
に減衰設定する。That is, the received signal level is -90 dBm.
And -70 dBm and larger than a predetermined -90 dBm, the step attenuator 3 is turned on to
An attenuation level of dB is applied, and a gain of 70 dB from the receiving input end to the optical transmission device (transmitting unit) 4 when not attenuated is 50 dB.
Set to decay.
【００２６】次に，受信信号レベルが−９０ｄＢｍ以下
で所定のレベルよりも小さいときには，ステップ減衰器
３はオフとして，減衰レベルを０ｄＢとして非減衰状態
とするので，受信入力端から光伝送装置（送信部）４ま
での利得が７０ｄＢとなり，光伝送装置（送信部）４の
入力端でのレベルは−２０ｄＢｍ未満となる。Next, when the received signal level is less than -90 dBm and smaller than a predetermined level, the step attenuator 3 is turned off and the attenuation level is set to 0 dB to bring the state into a non-attenuated state. The gain up to the transmission unit 4 is 70 dB, and the level at the input end of the optical transmission device (transmission unit) 4 is less than -20 dBm.
【００２７】したがって，弱信号受信時に，受信入力端
において，光伝送装置（送信部）４によるシステム雑音
温度劣化量を従来例の場合よりも２０ｄＢ低い０．２３
Ｋに低減出来，また光伝送装置（送信部）４の入力端で
の入力レベルの制約によって受信入力端でのダイナミッ
クレンジの制約を受けることも大幅に抑圧することが出
来る。Therefore, when a weak signal is received, the system noise temperature deterioration amount due to the optical transmission device (transmission unit) 4 at the receiving input end is 20 dB lower than that of the conventional example by 0.23.
It can be reduced to K, and the restriction of the dynamic range at the receiving input end due to the restriction of the input level at the input end of the optical transmission device (transmitting section) 4 can be greatly suppressed.
【００２８】図２は，図１の実施例の動作の説明図であ
る。FIG. 2 is an explanatory diagram of the operation of the embodiment shown in FIG.
【００２９】低雑音増幅器１ａ，受信周波数変換装置２
ならびにステップ減衰器３を含むＲＦ部は，ステップ減
衰器３による減衰が零のとき，７０ｄＢの利得に設定さ
れる。Low noise amplifier 1a, reception frequency converter 2
The RF section including the step attenuator 3 is set to a gain of 70 dB when the attenuation by the step attenuator 3 is zero.
【００３０】光伝送装置（送信部）４の最大入力レベル
は−２０ｄＢｍであり，この光伝送装置（送信部）４の
入力で発生する雑音温度ＴOPT は前述した従来例と同じ
６３．６ｄＢＫ（２．２９０．８６８Ｋ）である。The maximum input level of the optical transmission device (transmission unit) 4 is -20 dBm, and the noise temperature T OPT generated at the input of this optical transmission device (transmission unit) 4 is 63.6 dB ( 2.290.868K).
【００３１】ステップ減衰器３がオフ状態に設定される
とき，すなわち受信入力端におけるＲＦ信号の入力レベ
ルが−９０ｄＢｍ以下であるとき，ＲＦ部における利得
は７０ｄＢに保持され，これにより，受信入力端での光
伝送装置（送信部）４によってもたらされる入力換算の
雑音温度は，利得５０ｄＢの場合よりもパワー比でさら
に２０ｄＢ低い０，２３Ｋとなる。When the step attenuator 3 is set to the off state, that is, when the input level of the RF signal at the receiving input end is less than -90 dBm, the gain in the RF section is held at 70 dB, whereby the receiving input end is held. The input-referred noise temperature caused by the optical transmission device (transmission unit) 4 in the above is 0,23K, which is 20 dB lower in power ratio than in the case of a gain of 50 dB.
【００３２】また，受信入力端でのＲＦ信号のレベルが
高く，−９０ｄＢｍを超え，−９０ｄＢｍと−７０ｄＢ
ｍ間にあるときは，ステップ減衰器３が制御信号によっ
て−２０ｄＢの減衰を与えるようにオンとされ，ＲＦ部
における利得は２０ｄＢダウンさせて５０ｄＢに設定さ
れる。Further, the level of the RF signal at the receiving input end is high, exceeding -90 dBm, -90 dBm and -70 dBm.
When it is between m, the step attenuator 3 is turned on by the control signal so as to give an attenuation of -20 dB, and the gain in the RF section is set down to 50 dB by 20 dB down.
【００３３】この場合，光伝送装置（送信部）４の入力
レベルは，受信入力端のレベルが−７０ｄＢｍであった
とすれば，−２０ｄＢｍから−４０ｄＢｍにダウンさせ
られ，この場合も受信入力端での換算雑音温度は０．２
３Ｋとなる。In this case, the input level of the optical transmission device (transmitting section) 4 is lowered from -20 dBm to -40 dBm if the level at the receiving input end is -70 dBm, and in this case as well, at the receiving input end. Converted noise temperature is 0.2
It will be 3K.
【００３４】このようにして，光伝送装置（送信部）４
の入力ダイナミックレンジの制約を大幅に緩和し，かつ
受信入力端での雑音温度劣化量も著しく抑圧したものと
することができる。In this way, the optical transmission device (transmission unit) 4
The restriction on the input dynamic range of 1 can be greatly relaxed, and the noise temperature deterioration at the receiving input can be significantly suppressed.
【００３５】[0035]
【発明の効果】以上説明したように本発明は，光伝送装
置（送信部）の前段にステップ減衰器を設け，受信信号
レベルに対応したＡＧＣ電圧でステップ減衰器のオン／
オフを自動的に制御することにより，運用者の介入を必
要とせずに光伝送装置（送信部）から発生する雑音によ
る受信入力端におけるシステム雑音温度の劣化を著しく
抑圧し，かつ光伝送装置（送信部）の入力レベル制約に
よる受信入力端におけるダイナミックレンジの制約も著
しく緩和することが出来る効果がある。As described above, according to the present invention, the step attenuator is provided in the preceding stage of the optical transmission device (transmission unit), and the step attenuator is turned on / off by the AGC voltage corresponding to the received signal level.
By automatically controlling the OFF, deterioration of the system noise temperature at the receiving input end due to noise generated from the optical transmission device (transmission unit) can be significantly suppressed without requiring operator intervention, and the optical transmission device ( There is an effect that the restriction of the dynamic range at the receiving input end due to the input level restriction of the transmitter) can be remarkably relaxed.
【図１】本発明の一実施例の光伝送方式を用いた受信装
置の構成を示すブロック図である。FIG. 1 is a block diagram showing a configuration of a receiver using an optical transmission system according to an embodiment of the present invention.
【図２】図１における受信動作の説明図である。FIG. 2 is an explanatory diagram of a receiving operation in FIG.
【図３】従来の光伝送方式を用いた受信装置の構成を示
すブロック図である。FIG. 3 is a block diagram showing a configuration of a receiving device using a conventional optical transmission system.
【図４】図３における受信動作の説明図である。FIG. 4 is an explanatory diagram of a receiving operation in FIG.
１ 低雑音増幅装置 ２ 受信周波数変換装置 ３ ステップ減衰器 ４ 光伝送装置（送信部） ５ 光伝送装置（受信部） ６ 受信復調部 ７ コンパレータ ８ 伝送路 1 Low Noise Amplifier 2 Received Frequency Converter 3 Step Attenuator 4 Optical Transmitter (Transmitter) 5 Optical Transmitter (Receiver) 6 Receive Demodulator 7 Comparator 8 Transmission Line
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.5 識別記号 庁内整理番号 ＦＩ 技術表示箇所 Ｈ０４Ｂ 15/00 9298−5Ｋ ─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 5 Identification code Internal reference number FI technical display location H04B 15/00 9298-5K
Claims (1)
翔体の発するテレメータ情報を受けて受信復調する場合
に，入力ＲＦ信号を変換したＩＦ信号を光伝送装置によ
って伝送する光伝送方式を用いた受信装置において，前
記光伝送装置の送信部の入力側に前記ＩＦ信号をステッ
プ的に減衰させるステップ減衰器を設け，前記ステップ
減衰器を入力ＲＦ信号の強弱に応じて切り替えて受信入
力端から前記光伝送装置の送信入力までの利得を変化さ
せ，前記光伝送装置の送信部で発生する雑音によるシス
テム雑音温度の劣化を抑圧し，かつ受信入力端でのダイ
ナミックレンジを拡大することを特徴とする光伝送方式
を用いた受信装置。1. An optical transmission system in which an IF signal converted from an input RF signal is transmitted by an optical transmission device when a flying object such as an artificial satellite is tracked and receiving and demodulating by receiving telemeter information emitted by the flying object. In the receiver used, a step attenuator for stepwise attenuating the IF signal is provided on the input side of the transmitter of the optical transmission device, and the step attenuator is switched according to the strength of the input RF signal to receive the input terminal. To suppress the deterioration of the system noise temperature due to the noise generated in the transmission section of the optical transmission device and to expand the dynamic range at the reception input end by changing the gain from the optical transmission device to the transmission input of the optical transmission device. And a receiver using the optical transmission method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4044224A JPH05244027A (en) | 1992-03-02 | 1992-03-02 | Receiver using optical transmission system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4044224A JPH05244027A (en) | 1992-03-02 | 1992-03-02 | Receiver using optical transmission system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH05244027A true JPH05244027A (en) | 1993-09-21 |
Family
ID=12685575
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4044224A Withdrawn JPH05244027A (en) | 1992-03-02 | 1992-03-02 | Receiver using optical transmission system |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH05244027A (en) |
-
1992
- 1992-03-02 JP JP4044224A patent/JPH05244027A/en not_active Withdrawn
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A300 | Withdrawal of application because of no request for examination |
Free format text: JAPANESE INTERMEDIATE CODE: A300 Effective date: 19990518 |