JPH05102872A - Automatic level adjusting circuit - Google Patents
Automatic level adjusting circuitInfo
- Publication number
- JPH05102872A JPH05102872A JP25946891A JP25946891A JPH05102872A JP H05102872 A JPH05102872 A JP H05102872A JP 25946891 A JP25946891 A JP 25946891A JP 25946891 A JP25946891 A JP 25946891A JP H05102872 A JPH05102872 A JP H05102872A
- Authority
- JP
- Japan
- Prior art keywords
- transmission
- signal
- band pass
- temperature
- automatic
- 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
- Circuits Of Receivers In General (AREA)
Abstract
Description
【0001】[0001]
【産業上の利用分野】本発明は、伝送路における伝送損
失の変化を自動的に補償する自動レベル調整回路(AL
C回路)に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic level adjusting circuit (AL) for automatically compensating for changes in transmission loss in a transmission line.
C circuit).
【0002】[0002]
【従来の技術】図2は、従来の自動レベル調整回路を備
えた高周波信号伝送装置の構成例を示すブロック図であ
る。2. Description of the Related Art FIG. 2 is a block diagram showing a configuration example of a high-frequency signal transmission device having a conventional automatic level adjusting circuit.
【0003】図において、高周波信号伝送装置の基本構
成は、伝送路20を介して送信側に配置される送信器2
1および変調器22と、受信側に配置される復調器23
および受信器24であり、その間で高周波信号の伝送が
行われる。In the figure, the basic configuration of a high-frequency signal transmission device is a transmitter 2 arranged on the transmission side via a transmission line 20.
1 and modulator 22, and demodulator 23 arranged on the receiving side
And a receiver 24, between which high-frequency signals are transmitted.
【0004】ところで、伝送路20は温度変化その他の
要因によって特性が変化し、高周波信号の受信レベルは
伝送路20における伝送損失の変化に伴って変動する。
そこで、受信レベルが一定になるように制御して伝送路
20の特性変化を抑圧する自動レベル調整回路が用いら
れる。従来の自動レベル調整回路は、送信側で送信器2
1と変調器22との間に挿入されるパイロット信号挿入
部30と、受信側で復調器23と受信器24との間に挿
入される自動レベル調整部40とに分けられる。By the way, the characteristics of the transmission line 20 change due to temperature changes and other factors, and the reception level of the high-frequency signal fluctuates as the transmission loss of the transmission line 20 changes.
Therefore, an automatic level adjustment circuit is used that controls the reception level to be constant and suppresses the characteristic change of the transmission line 20. The conventional automatic level adjustment circuit uses the transmitter 2 on the transmission side.
1 and a modulator 22, and a pilot signal insertion unit 30 inserted between the demodulator 23 and the receiver 24 on the receiving side.
【0005】パイロット信号挿入部30では、パイロッ
ト信号発生器31が送信器21から送信される伝送信号
とは異なる周波数帯域のパイロット信号を発生し、その
パイロット信号を固定減衰器32を介して所定のレベル
に設定する。さらに、帯域通過フィルタ33を介してパ
イロット信号の周波数成分のみを取り出し、カプラ34
で伝送信号に重畳して変調器22に送る。In the pilot signal inserting section 30, the pilot signal generator 31 generates a pilot signal in a frequency band different from the transmission signal transmitted from the transmitter 21, and the pilot signal is passed through the fixed attenuator 32 to a predetermined value. Set to level. Further, only the frequency component of the pilot signal is extracted via the band pass filter 33, and the coupler 34
And superimposes it on the transmission signal and sends it to the modulator 22.
【0006】一方、復調器23で復調された信号は、自
動レベル調整部40の自動利得制御増幅器(AGCアン
プ)41を介してカプラ42に入力される。カプラ42
は入力信号を二分し、その一方を伝送信号の周波数成分
のみを通過させる帯域通過フィルタ(BPF)43を介
して受信器24に送り、その他方をパイロット信号の周
波数成分のみを通過させる帯域通過フィルタ(BPF)
44を介して検波器45に送る。検波器45は、パイロ
ット信号を検波してその受信レベルに応じた電圧を出力
する。比較器46は、参照電圧発生器47が発生する参
照電圧と検波器45の出力電圧とを比較することによ
り、伝送路20の伝送損失の変化に応じて生じるパイロ
ット信号のレベル変動分に相当する差分電圧を得る。自
動利得制御増幅器41の駆動回路48は、比較器47か
ら出力される差分電圧がゼロになるように自動利得制御
増幅器41の利得を調整してパイロット信号のレベル変
動分を補償し、併せて送信器21から送信された伝送信
号についての伝送損失分を補償する。なお、検波器4
5,比較器46,参照電圧発生器47および駆動回路4
8は、自動レベル制御部を構成する。On the other hand, the signal demodulated by the demodulator 23 is input to the coupler 42 via the automatic gain control amplifier (AGC amplifier) 41 of the automatic level adjusting section 40. Coupler 42
Is a bandpass filter that divides the input signal into two parts, one of which is sent to the receiver 24 through a bandpass filter (BPF) 43 that passes only the frequency component of the transmission signal, and the other is a bandpass filter that passes only the frequency component of the pilot signal. (BPF)
It sends to the wave detector 45 via 44. The detector 45 detects the pilot signal and outputs a voltage corresponding to its reception level. The comparator 46 compares the reference voltage generated by the reference voltage generator 47 with the output voltage of the detector 45, and corresponds to the level variation of the pilot signal generated according to the change of the transmission loss of the transmission line 20. Get the differential voltage. The drive circuit 48 of the automatic gain control amplifier 41 adjusts the gain of the automatic gain control amplifier 41 so that the differential voltage output from the comparator 47 becomes zero, compensates for the level fluctuation of the pilot signal, and transmits it at the same time. The transmission loss of the transmission signal transmitted from the device 21 is compensated. In addition, the detector 4
5, comparator 46, reference voltage generator 47 and drive circuit 4
8 constitutes an automatic level control unit.
【0007】このような構成により、伝送路20の特性
変化で生じる受信レベルの変動が抑圧され、安定した信
号伝送を実現することができる。With such a configuration, fluctuations in the reception level caused by changes in the characteristics of the transmission line 20 are suppressed, and stable signal transmission can be realized.
【0008】[0008]
【発明が解決しようとする課題】ところで、従来の自動
レベル調整回路では、伝送信号の受信レベルの調整は、
それに重畳して伝送されたパイロット信号の受信レベル
の変動を検出しそれを補償する構成により行っている。
しかし、伝送路20における伝送損失の変化分について
は従来の構成で十分に抑圧可能であるが、カプラ42以
降の伝送信号の通過経路にある帯域通過フィルタ43
と、パイロット信号の通過経路にある帯域通過フィルタ
44との温度特性が異なる場合に、パイロット信号を基
準にしたレベル調整では帯域通過フィルタ43,44の
温度特性の違いによるレベル変動までは吸収できなかっ
た。By the way, in the conventional automatic level adjustment circuit, the adjustment of the reception level of the transmission signal is performed as follows.
This is performed by a configuration that detects variations in the reception level of the pilot signal transmitted superimposed on it and compensates for it.
However, although the change in the transmission loss in the transmission line 20 can be sufficiently suppressed by the conventional configuration, the band pass filter 43 in the transmission path of the transmission signal after the coupler 42.
And the temperature characteristics of the band pass filter 44 in the passage of the pilot signal are different, the level adjustment based on the pilot signal cannot absorb the level fluctuation due to the difference of the temperature characteristics of the band pass filters 43 and 44. It was
【0009】本発明は、伝送路における伝送損失の変化
を抑圧する機能に加えて、伝送信号およびパイロット信
号をそれぞれ通過させる帯域通過フィルタで温度変化に
よって生じる通過損失の変化を自動的に抑圧することが
できる自動レベル調整回路を提供することを目的とす
る。According to the present invention, in addition to the function of suppressing the change of the transmission loss in the transmission line, the band-pass filter for passing the transmission signal and the pilot signal respectively automatically suppresses the change of the passage loss caused by the temperature change. It is an object of the present invention to provide an automatic level adjustment circuit capable of performing the above.
【0010】[0010]
【課題を解決するための手段】本発明は、送信側に、伝
送信号にパイロット信号を重畳して伝送路に送出するパ
イロット信号挿入部を備え、受信側に、受信信号の利得
を制御する自動利得制御増幅器と、受信信号から前記伝
送信号を選択して後段の受信器に送出する第1の帯域通
過フィルタと、受信信号から前記パイロット信号を選択
する第2の帯域通過フィルタと、前記第2の帯域通過フ
ィルタを介して得られたパイロット信号のレベルと参照
電圧とを比較し、得られた差信号に応じて前記自動利得
制御増幅器を制御して前記伝送路における伝送損失の変
化を抑圧する自動レベル制御部とを備えた自動レベル調
整回路において、前記第1の帯域通過フィルタおよび前
記第2の帯域通過フィルタの周辺温度を検出する温度検
出手段と、前記温度検出手段で得られた周辺温度情報を
取り込んで前記各帯域通過フィルタにおける通過損失の
温度特性差を割り出し、前記自動レベル制御部にその温
度特性差を相殺する参照電圧を設定する演算処理手段と
を備えたことを特徴とする。According to the present invention, a transmitting side is provided with a pilot signal inserting section for superimposing a pilot signal on a transmission signal and sending it out to a transmission line, and a receiving side is provided with an automatic control for controlling the gain of the received signal. A gain control amplifier, a first band pass filter for selecting the transmission signal from the received signal and sending it to a receiver at a subsequent stage, a second band pass filter for selecting the pilot signal from the received signal, and the second Comparing the level of the pilot signal obtained through the band-pass filter with the reference voltage, and controlling the automatic gain control amplifier according to the obtained difference signal to suppress the change of the transmission loss in the transmission line. In an automatic level adjusting circuit including an automatic level control unit, temperature detecting means for detecting an ambient temperature of the first band pass filter and the second band pass filter; An arithmetic processing unit that takes in the ambient temperature information obtained by the detection unit to determine the temperature characteristic difference of the pass loss in each of the band pass filters, and sets a reference voltage that cancels the temperature characteristic difference in the automatic level control unit. It is characterized by having.
【0011】[0011]
【作用】本発明は、自動レベル制御部でパイロット信号
のレベル比較の基準となる参照電圧を固定とせず、伝送
信号を通過させる第1の帯域通過フィルタとパイロット
信号を通過させる第2の帯域通過フィルタの温度特性の
差を相殺する参照電圧を設定する。According to the present invention, the automatic level control section does not fix the reference voltage as a reference for level comparison of pilot signals, but the first band pass filter for passing the transmission signal and the second band pass for passing the pilot signal. Set the reference voltage that cancels the difference in the temperature characteristics of the filter.
【0012】すなわち、演算処理手段が温度検出手段で
検出される各帯域通過フィルタの周辺温度を取り込み、
各帯域通過フィルタの温度特性の差を相殺するような参
照電圧を割り出して設定することにより、パイロット信
号のレベルを伝送信号のレベルに換算してレベル調整を
行うことができる。したがって、パイロット信号を監視
しながら各帯域通過フィルタの温度特性の差を吸収で
き、伝送信号について伝送路における伝送損失の変化を
確実に抑圧することができる。That is, the arithmetic processing means fetches the ambient temperature of each band pass filter detected by the temperature detecting means,
By determining and setting the reference voltage that cancels the difference in the temperature characteristics of each band pass filter, the level of the pilot signal can be converted into the level of the transmission signal for level adjustment. Therefore, it is possible to absorb the difference in the temperature characteristics of the band pass filters while monitoring the pilot signal, and reliably suppress the change in the transmission loss of the transmission signal in the transmission path.
【0013】[0013]
【実施例】図1は、本発明の一実施例構成を示すブロッ
ク図である。なお、本実施例は、従来技術の説明で用い
た高周波信号伝送装置の構成に基づいて説明する。した
がって、伝送路20を介して接続される送信器21,変
調器22および復調器23,受信器24による基本構成
と、パイロット信号発生器31,固定減衰器32,帯域
通過フィルタ(BPF)33およびカプラ34により構
成されるパイロット信号挿入部30と、自動利得制御増
幅器(AGCアンプ)41,カプラ42,帯域通過フィ
ルタ(BPF)43,44は従来と同様である。1 is a block diagram showing the configuration of an embodiment of the present invention. The present embodiment will be described based on the configuration of the high-frequency signal transmission device used in the description of the prior art. Therefore, the basic configuration including the transmitter 21, the modulator 22, the demodulator 23, and the receiver 24 connected via the transmission path 20, the pilot signal generator 31, the fixed attenuator 32, the bandpass filter (BPF) 33, and The pilot signal insertion unit 30 including the coupler 34, the automatic gain control amplifier (AGC amplifier) 41, the coupler 42, and the bandpass filters (BPF) 43 and 44 are the same as those in the conventional case.
【0014】本実施例の特徴とするところは、まず受信
側に設けられる自動レベル調整部10の自動レベル制御
部において、検波器45,比較器46および駆動回路4
8は従来と同様であるが、参照電圧発生器11が発生す
る参照電圧を外部からの制御によって変更できる構成で
ある。さらに、帯域通過フィルタ43,44の周辺温度
を検出する温度検出器12を設け、温度検出器12で得
た温度情報に応じて参照電圧発生部11が発生する参照
電圧を制御する演算処理手段として、演算処理部(CP
U)13とメモリ14とを備えた構成にある。The feature of this embodiment is that in the automatic level control section of the automatic level adjusting section 10 provided on the receiving side, the detector 45, the comparator 46 and the drive circuit 4 are first provided.
Although 8 is the same as the conventional one, the reference voltage generated by the reference voltage generator 11 can be changed by external control. Further, a temperature detector 12 that detects the ambient temperature of the bandpass filters 43 and 44 is provided, and as a calculation processing unit that controls the reference voltage generated by the reference voltage generation unit 11 according to the temperature information obtained by the temperature detector 12. , Arithmetic processing unit (CP
U) 13 and the memory 14.
【0015】なお、本実施例では、メモリ14に各帯域
通過フィルタ43,44の通過損失の温度特性データを
あらかじめ記憶し、演算処理部13が温度検出器12で
得た各帯域通過フィルタ43,44の周辺温度に応じ
て、メモリ14から対応する温度特性データを読み出
し、各帯域通過フィルタにおける通過損失の違いを相殺
する参照電圧を算出する構成を特徴とする。In this embodiment, the temperature characteristic data of the pass loss of each of the band pass filters 43, 44 is stored in the memory 14 in advance, and the arithmetic processing unit 13 obtains each of the band pass filters 43, 44 obtained by the temperature detector 12. It is characterized in that corresponding temperature characteristic data is read from the memory 14 in accordance with the ambient temperature of 44, and a reference voltage for canceling the difference in the pass loss in each band pass filter is calculated.
【0016】したがって、本実施例の構成によれば、演
算処理部13が各帯域通過フィルタ43,44の温度特
性の差を相殺するような参照電圧を参照電圧発生器11
に設定することにより、パイロット信号のレベルを基準
にした自動レベル調整であっても、間接的ながら伝送信
号のレベルの変動を確実に抑圧することができる。Therefore, according to the configuration of this embodiment, the reference voltage generator 11 generates the reference voltage that the arithmetic processing unit 13 cancels the difference in the temperature characteristics of the band pass filters 43 and 44.
By setting to, even if automatic level adjustment is performed with reference to the level of the pilot signal, it is possible to reliably suppress fluctuations in the level of the transmission signal indirectly.
【0017】なお、本発明は、温度変化による伝送損失
の変化が大きい光伝送システムにおいて特に有効である
が、その場合には、変調器22,伝送路20および復調
器23は、それぞれ電気/光変換器,光ファイバケーブ
ル,光/電気変換器となる。The present invention is particularly effective in an optical transmission system in which a change in transmission loss due to a change in temperature is large, but in that case, the modulator 22, the transmission line 20, and the demodulator 23 are respectively electrically / optical. It becomes a converter, an optical fiber cable, and an optical / electrical converter.
【0018】[0018]
【発明の効果】以上説明したように本発明は、高周波信
号を低損失で伝送する高周波信号伝送装置その他の伝送
システムにおいて、伝送路および受信端での温度変化に
よるレベル変化を確実を抑圧することができ、伝送信号
の受信レベルを極めて安定したものにすることができ
る。As described above, according to the present invention, in a high-frequency signal transmission device or other transmission system that transmits a high-frequency signal with low loss, it is possible to reliably suppress a level change due to a temperature change in a transmission line and a receiving end. Therefore, the reception level of the transmission signal can be made extremely stable.
【図1】本発明の一実施例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.
【図2】従来の自動レベル調整回路を備えた高周波信号
伝送装置の構成例を示すブロック図である。FIG. 2 is a block diagram showing a configuration example of a high-frequency signal transmission device including a conventional automatic level adjustment circuit.
10 自動レベル調整部 11 参照電圧発生器 12 温度検出器 13 演算処理部(CPU) 14 メモリ 20 伝送路 21 送信器 22 変調器 23 復調器 24 受信器 30 パイロット信号挿入部 31 パイロット信号発生器 32 固定減衰器 33 帯域通過フィルタ(BPF) 34 カプラ 40 自動レベル調整部 41 自動利得制御増幅器(AGCアンプ) 42 カプラ 43,44 帯域通過フィルタ(BPF) 45 検波器 46 比較器 47 参照電圧発生器 48 駆動回路 10 Automatic Level Adjustment Unit 11 Reference Voltage Generator 12 Temperature Detector 13 Calculation Processing Unit (CPU) 14 Memory 20 Transmission Line 21 Transmitter 22 Modulator 23 Demodulator 24 Receiver 30 Pilot Signal Insertion Unit 31 Pilot Signal Generator 32 Fixed Attenuator 33 Band pass filter (BPF) 34 Coupler 40 Automatic level adjusting unit 41 Automatic gain control amplifier (AGC amplifier) 42 Coupler 43,44 Band pass filter (BPF) 45 Detector 46 Comparator 47 Reference voltage generator 48 Drive circuit
Claims (1)
重畳して伝送路に送出するパイロット信号挿入部を備
え、 受信側に、受信信号の利得を制御する自動利得制御増幅
器と、受信信号から前記伝送信号を選択して後段の受信
器に送出する第1の帯域通過フィルタと、受信信号から
前記パイロット信号を選択する第2の帯域通過フィルタ
と、前記第2の帯域通過フィルタを介して得られたパイ
ロット信号のレベルと参照電圧とを比較し、得られた差
信号に応じて前記自動利得制御増幅器を制御して前記伝
送路における伝送損失の変化を抑圧する自動レベル制御
部とを備えた自動レベル調整回路において、 前記第1の帯域通過フィルタおよび前記第2の帯域通過
フィルタの周辺温度を検出する温度検出手段と、 前記温度検出手段で得られた周辺温度情報を取り込んで
前記各帯域通過フィルタにおける通過損失の温度特性差
を割り出し、前記自動レベル制御部にその温度特性差を
相殺する参照電圧を設定する演算処理手段とを備えたこ
とを特徴とする自動レベル調整回路。1. A transmission side is provided with a pilot signal insertion section for superimposing a pilot signal on a transmission signal and sending it out to a transmission line, and a reception side is provided with an automatic gain control amplifier for controlling the gain of the reception signal, and a reception signal It is obtained via a first band pass filter for selecting the transmission signal and sending it to a receiver at a subsequent stage, a second band pass filter for selecting the pilot signal from the received signal, and a second band pass filter. An automatic level control unit for comparing the level of the pilot signal and the reference voltage, and controlling the automatic gain control amplifier according to the obtained difference signal to suppress the change of the transmission loss in the transmission line. In the automatic level adjusting circuit, a temperature detecting unit that detects the ambient temperature of the first band-pass filter and the second band-pass filter, and the ambient temperature obtained by the temperature detecting unit. Arithmetic processing means for fetching temperature information to determine a temperature characteristic difference of the pass loss in each of the band pass filters, and setting a reference voltage for canceling the temperature characteristic difference in the automatic level control unit. Automatic level adjustment circuit.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP25946891A JPH05102872A (en) | 1991-10-07 | 1991-10-07 | Automatic level adjusting circuit |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP25946891A JPH05102872A (en) | 1991-10-07 | 1991-10-07 | Automatic level adjusting circuit |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH05102872A true JPH05102872A (en) | 1993-04-23 |
Family
ID=17334498
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP25946891A Pending JPH05102872A (en) | 1991-10-07 | 1991-10-07 | Automatic level adjusting circuit |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH05102872A (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0903010A1 (en) * | 1996-05-31 | 1999-03-24 | Scientific-Atlanta, Inc. | Method and apparatus for dynamic automatic gain control when pilot signal is lost |
JP2001160780A (en) * | 1999-12-03 | 2001-06-12 | Sumitomo Electric Ind Ltd | Distributed compensation module, line switch device and optical communication system |
US6587012B1 (en) * | 1999-10-01 | 2003-07-01 | Arris International, Inc. | Automatic slope and gain (ASG) detector technique including a pilot signal |
-
1991
- 1991-10-07 JP JP25946891A patent/JPH05102872A/en active Pending
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0903010A1 (en) * | 1996-05-31 | 1999-03-24 | Scientific-Atlanta, Inc. | Method and apparatus for dynamic automatic gain control when pilot signal is lost |
EP0903010A4 (en) * | 1996-05-31 | 1999-04-07 | ||
US6587012B1 (en) * | 1999-10-01 | 2003-07-01 | Arris International, Inc. | Automatic slope and gain (ASG) detector technique including a pilot signal |
JP2001160780A (en) * | 1999-12-03 | 2001-06-12 | Sumitomo Electric Ind Ltd | Distributed compensation module, line switch device and optical communication system |
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