JPH0638508Y2 - Automatic transmission cable loss compensator - Google Patents
Automatic transmission cable loss compensatorInfo
- Publication number
- JPH0638508Y2 JPH0638508Y2 JP1985169403U JP16940385U JPH0638508Y2 JP H0638508 Y2 JPH0638508 Y2 JP H0638508Y2 JP 1985169403 U JP1985169403 U JP 1985169403U JP 16940385 U JP16940385 U JP 16940385U JP H0638508 Y2 JPH0638508 Y2 JP H0638508Y2
- Authority
- JP
- Japan
- Prior art keywords
- signal
- cable
- frequency
- transmission cable
- transmission
- 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
Landscapes
- Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
- Closed-Circuit Television Systems (AREA)
Description
【考案の詳細な説明】 〈産業上の利用分野〉 本考案は例えばビデオカメラで撮影した映像情報を長い
伝送ケーブルを使用して遠方に設置されたVTR等の受信
機まで伝送する際等に生ずる伝送ケーブルロスを自動的
に補償する装置に関するものである。[Detailed Description of the Invention] <Industrial field of application> The present invention occurs, for example, when transmitting video information captured by a video camera to a receiver such as a VTR installed at a distance using a long transmission cable. The present invention relates to a device that automatically compensates for transmission cable loss.
〈考案の概要〉 本考案では送信機から受信機に伝送ケーブルを介して信
号を伝送する信号伝送システムにおいて、所定時に送信
機側から高周波信号を重畳させて伝送し、受信機側では
この高周波信号を検波しそのときの検波出力レベルに応
じてケーブル長を判別して伝送ケーブルロスを自動的に
補償するものである。<Outline of the Invention> In the present invention, in a signal transmission system in which a signal is transmitted from a transmitter to a receiver via a transmission cable, a high frequency signal is superimposed and transmitted from the transmitter side at a predetermined time, and the high frequency signal is transmitted to the receiver side. Is detected and the cable length is determined according to the detection output level at that time to automatically compensate the transmission cable loss.
〈従来の技術〉 一般に送受信機器間を接続する伝送ケーブルには銅線抵
抗による低域ロスと分布定数による高域ロスが存在し、
高精度が要求される機器においては送信側でプリエンフ
ァシスをかけて送信する方法や、また受信側で信号ロス
を検出しそれに見合った補償を行なう方法が採用されて
いる。<Prior art> Generally, a transmission cable connecting transmission / reception devices has a low frequency loss due to a copper wire resistance and a high frequency loss due to a distributed constant.
In equipment requiring high accuracy, a method of transmitting by applying pre-emphasis on the transmitting side, and a method of detecting signal loss on the receiving side and compensating for it are adopted.
第２図には従来からビデオカメラのような送信機とVTR
のような受信機とを伝送ケーブルを用いて結合する信号
伝送システムにおいて採用されている伝送ケーブルロス
自動補償装置の一例を示し、以下これについて説明する
と、ここで１はビデオカメラ、２は受信機、３は伝送ケ
ーブルであり、特に自動補償装置は受信機２内に内蔵さ
れている。即ちこの場合受信機２内の入力回路側にバー
ストゲート回路４とケーブル長判別回路５と利得制御増
幅器６とからなる伝送ケーブルロス自動補償装置が設け
られ、ビデオカメラ１にて撮影された映像信号が伝送ケ
ーブル３を介して受信機２に供給されたとき、受信機２
内ではこの映像信号が入力増幅器７及び利得制御増幅器
６にてそれぞれ増幅されたのち後段の信号処理回路８に
供給されて適宜の処理が施こされるが、このときまた利
得制御増幅器６より出力される映像信号がバーストゲー
ト回路４に加えられここでバースト信号成分のみが抜取
られケーブル長判別回路５に供給される。ケーブル長判
別回路５ではベースト信号レベルの減衰量を検知してケ
ーブル長が判別され、このとき得られる出力が利得制御
増幅器６に供給される。これにより利得制御増幅器６の
利得がケーブル長によるバースト信号レベルの減衰量に
応じて制御され、このような結果ビデオカメラ１より伝
送ケーブル３を介して得られる映像信号のケーブルロス
が自動的に補償されることになる。Fig. 2 shows a conventional transmitter such as a video camera and a VTR.
An example of a transmission cable loss automatic compensator used in a signal transmission system in which a receiver such as the above is coupled by using a transmission cable is described below. The description will be given below with reference to 1 is a video camera and 2 is a receiver. 3 is a transmission cable, and in particular, an automatic compensator is built in the receiver 2. That is, in this case, a transmission cable loss automatic compensating device including a burst gate circuit 4, a cable length discriminating circuit 5 and a gain control amplifier 6 is provided on the input circuit side in the receiver 2, and a video signal captured by the video camera 1 is provided. Is supplied to the receiver 2 via the transmission cable 3, the receiver 2
In the inside, this video signal is amplified by the input amplifier 7 and the gain control amplifier 6, respectively, and then supplied to the signal processing circuit 8 in the subsequent stage to be subjected to appropriate processing. The generated video signal is applied to the burst gate circuit 4, where only the burst signal component is extracted and supplied to the cable length determination circuit 5. The cable length discriminating circuit 5 discriminates the cable length by detecting the attenuation amount of the basal signal level, and the output obtained at this time is supplied to the gain control amplifier 6. As a result, the gain of the gain control amplifier 6 is controlled according to the amount of attenuation of the burst signal level due to the cable length, and as a result, the cable loss of the video signal obtained from the video camera 1 via the transmission cable 3 is automatically compensated. Will be done.
〈考案が解決しようとする問題点〉 ところが上記のような従来の自動補償装置では受信機側
での映像信号中に含まれるバースト信号のレベルを検知
して伝送ケーブルロスを判定しているが、このバースト
信号自身は水平同期信号のバックポーチ部に間歇的に挿
入されて伝送されて来るため、余程ケーブルが長くない
限りバースト信号レベルの微小な減衰を正確に検知する
ことは難しく、この検知判別にはかなりの高い精度が必
要となっていた。<Problems to be solved by the invention> However, in the conventional automatic compensator as described above, the transmission cable loss is judged by detecting the level of the burst signal included in the video signal on the receiver side. Since this burst signal itself is intermittently inserted and transmitted in the back porch of the horizontal sync signal, it is difficult to accurately detect minute attenuation of the burst signal level unless the cable is long enough. A fairly high accuracy was required for the discrimination.
〈問題点を解決するための手段〉 本考案はこのような点に鑑みなされたものであり、送信
機から受信機に伝送ケーブルを介して信号を伝送する信
号伝送システムにおいて、 特に送信機側には所定期間に高周波信号を発振させる高
周波発振手段と、該手段にて発振された高周波信号を伝
送信号に重畳させる高周波重畳手段と、高周波発振手段
と高周波重畳手段との間に接続された第１のスイッチと
を設け、一方受信機側には送信機側より伝送ケーブルを
介して重畳伝送されて来る高周波信号を検波する高周波
検波手段と、該手段より得られる検波出力レベルにより
ケーブル長を判別するケーブル長判別手段と、該手段に
よる判別出力に基いて伝送信号の利得を制御する利得制
御手段と、高周波検波手段と利得制御手段との間に接続
された第２のスイッチとを設けてなるものである。<Means for Solving Problems> The present invention has been made in view of such a point, and in a signal transmission system for transmitting a signal from a transmitter to a receiver via a transmission cable, particularly on the transmitter side. Is a high-frequency oscillating means for oscillating a high-frequency signal in a predetermined period, a high-frequency superposing means for superposing the high-frequency signal oscillated by the means on a transmission signal, and a first connection connected between the high-frequency oscillating means and the high-frequency superposing means. Switch is provided on the one hand, and on the other hand, the receiver side detects the high frequency signal superposed and transmitted from the transmitter side via the transmission cable, and the cable length is discriminated by the detection output level obtained from this means. A cable length discriminating means, a gain control means for controlling the gain of the transmission signal based on the discriminative output by the means, and a second connecting means between the high frequency detecting means and the gain controlling means. Those formed by providing a switch.
〈作用〉 従ってこの場合、送信機側より伝送ケーブルを介して受
信機側に信号を伝送する際に受信機側で伝送ケーブルロ
スに見合った補償が自動的に行なわれる。<Operation> Therefore, in this case, when the signal is transmitted from the transmitter side to the receiver side via the transmission cable, the receiver side automatically compensates for the transmission cable loss.
〈実施例〉 以下図面に示す実施例に従って本考案を説明する。第１
図は本考案装置の１実施例を示し、ここで第２図に示す
従来例と同一部分には同一符号を附記している。<Embodiment> The present invention will be described below with reference to an embodiment shown in the drawings. First
The drawing shows one embodiment of the device of the present invention, in which the same parts as those in the conventional example shown in FIG.
ここでは特にビデオカメラ１側に高周波発振器９とスイ
ッチ10を設け、一方受信機２内に高周波発振器11とスイ
ッチ12を設けたものである。Here, in particular, a high frequency oscillator 9 and a switch 10 are provided on the video camera 1 side, while a high frequency oscillator 11 and a switch 12 are provided in the receiver 2.
そしてここで撮影操作の開始に先立ってまず双方のスイ
ッチ10,12を一時的に投入すると、このとき所定期間だ
け前記発振器９の発振動作が行なわれ、このとき発振さ
れた高周波信号が映像信号に重畳され伝送ケーブル３と
介して受信機２側に供給される。このとき受信機２内で
は、高周波重畳映像信号が入力増幅器７及び利得制御増
幅器６にて増幅されたのち信号処理回路８に供給される
が、さらにここでは高周波信号成分のみが高周波検波回
路11にて検波され、このとき検波出力がスイッチ12を介
してケーブル長判別回路５に加えられ、その検波出力レ
ベルに応じてケーブル長が判別される。こうして一旦ケ
ーブル長が判別されると、その後たとえスイッチ10,12
にオフ状態となっても前記の判別内容がこの判別回路５
内で記憶保持され、このときの判別出力に基いて利得制
御増幅器６が常時一定の利得で増幅される。このような
結果受信機器２内ではビデオカメラ１より伝送ケーブル
３を介して得られる映像信号のケーブルロスが自動的に
補償されることになる。If both switches 10 and 12 are temporarily turned on before the start of the photographing operation, the oscillator 9 is oscillated for a predetermined period at this time, and the high frequency signal oscillated at this time is converted into a video signal. It is superimposed and supplied to the receiver 2 side via the transmission cable 3. At this time, in the receiver 2, the high frequency superimposed video signal is amplified by the input amplifier 7 and the gain control amplifier 6 and then supplied to the signal processing circuit 8. Further, here, only the high frequency signal component is supplied to the high frequency detection circuit 11. Then, the detected output is applied to the cable length determination circuit 5 via the switch 12, and the cable length is determined according to the detected output level. In this way, once the cable length is determined, even if
Even if it is turned off, the determination content is the same as the determination circuit 5 described above.
It is stored and held in the gain control amplifier 6, and the gain control amplifier 6 is always amplified with a constant gain based on the discrimination output at this time. As a result, in the receiving device 2, the cable loss of the video signal obtained from the video camera 1 via the transmission cable 3 is automatically compensated.
〈考案の効果〉 以上のように本考案の伝送ケーブルロス自動補償装置に
よれば、送信機から受信機に伝送ケーブルを介して信号
を伝送する信号伝送システムにおいて、伝送ケーブルの
使用に先立って一時的に送信機側のスイッチと受信機側
のスイッチとを投入することにより、一時的に送信機側
から高周波信号を重畳させて伝送し、受信機側ではこの
高周波信号を検波し、そのときの検波出力レベルに応じ
てケーブル長を判別して伝送ケーブルロスを自動的に補
償するものであるから、高周波信号成分の減衰を検知し
てケーブル長を正確に判別することができ、従ってこれ
に基いてケーブルロスを高精度で補償することが可能と
なり、しかも必要な信号の伝送時には検査用の高周波信
号が重畳されないので必要な信号に妨害を全く与えない
という特徴がある。<Advantages of Device> As described above, according to the transmission cable loss automatic compensator of the present invention, in a signal transmission system in which a signal is transmitted from a transmitter to a receiver via the transmission cable, it is possible to temporarily By turning on the switch on the transmitter side and the switch on the receiver side, the high frequency signal is temporarily superimposed and transmitted from the transmitter side, and the high frequency signal is detected on the receiver side. Since the cable length is determined according to the detection output level and transmission cable loss is automatically compensated for, the attenuation of high frequency signal components can be detected to accurately determine the cable length. The cable loss can be compensated with high accuracy, and high-frequency signals for inspection are not superposed at the time of transmission of the required signal, so the required signal must not be disturbed at all. There is a feature called.
第１図は本考案装置の１実施例を示すブロック図、第２
図は従来装置のブロック図である。 １……ビデオカメラ、２……受信機、３……伝送ケーブ
ル、５……ケーブル長判別回路、６……利得制御増幅
器、９……高周波発振器。FIG. 1 is a block diagram showing an embodiment of the device of the present invention, and FIG.
The figure is a block diagram of a conventional device. 1 ... Video camera, 2 ... Receiver, 3 ... Transmission cable, 5 ... Cable length determination circuit, 6 ... Gain control amplifier, 9 ... High frequency oscillator.
Claims (1)
信号を伝送する信号伝送システムにおいて、 前記送信機側には所定期間に高周波信号を発振させる高
周波発振手段と、該手段にて発振された高周波信号を伝
送信号に重畳させる高周波重畳手段と、前記高周波発振
手段と前記高周波重畳手段との間に接続された第１のス
イッチとを設け、 前記受信機側には送信機側より伝送ケーブルを介して重
畳伝送されて来る高周波信号を検波する高周波検波手段
と、該手段より得られる検波出力レベルによりケーブル
長を判別するケーブル長判別手段と、該手段による判別
出力に基いて伝送信号の利得を制御する利得制御手段
と、前記高周波検波手段と前記利得制御手段との間に接
続された第２のスイッチとを設けるようにしたことを特
徴とする伝送ケーブルロス自動補償装置。1. A signal transmission system for transmitting a signal from a transmitter to a receiver via a transmission cable, wherein the transmitter has a high-frequency oscillating means for oscillating a high-frequency signal for a predetermined period, and the means oscillates. And a first switch connected between the high-frequency oscillating means and the high-frequency superimposing means, and a transmission cable from the transmitter side to the receiver side. High-frequency detection means for detecting a high-frequency signal superposed and transmitted through the cable, cable length determination means for determining the cable length based on the detection output level obtained by the means, and gain of the transmission signal based on the determination output by the means. And a second switch connected between the high frequency detection means and the gain control means. Cable loss automatic compensation device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1985169403U JPH0638508Y2 (en) | 1985-10-31 | 1985-10-31 | Automatic transmission cable loss compensator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1985169403U JPH0638508Y2 (en) | 1985-10-31 | 1985-10-31 | Automatic transmission cable loss compensator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6277935U JPS6277935U (en) | 1987-05-19 |
| JPH0638508Y2 true JPH0638508Y2 (en) | 1994-10-05 |
Family
ID=31103178
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1985169403U Expired - Lifetime JPH0638508Y2 (en) | 1985-10-31 | 1985-10-31 | Automatic transmission cable loss compensator |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0638508Y2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2673598B2 (en) * | 1990-05-31 | 1997-11-05 | 日本電信電話株式会社 | Video signal transmission system |
| US7221389B2 (en) * | 2002-02-15 | 2007-05-22 | Avocent Corporation | Automatic equalization of video signals |
| US9560371B2 (en) | 2003-07-30 | 2017-01-31 | Avocent Corporation | Video compression system |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5880936A (en) * | 1981-11-09 | 1983-05-16 | Yagi Antenna Co Ltd | Fm signal transmission system |
-
1985
- 1985-10-31 JP JP1985169403U patent/JPH0638508Y2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6277935U (en) | 1987-05-19 |
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