JPH0633511Y2 - Connection circuit for multiple display devices that display the same screen - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention connects a plurality of display devices for displaying the same screen when information display such as a stock price reporting device is performed by display devices provided in a plurality of places. Regarding the circuit.

[Conventional technology and its problems]

Conventionally, a T-type branch connector was used, one of which was used as a video input terminal and the other two were used as video output terminals, and a cathode ray tube (CRT) was connected to these two video output terminals. There are problems that the number of units and the total length of the connecting cable are limited, and that noise due to reflected waves and the like is mixed into the video signal, and the quality of the display screen is impaired.

[Means for Solving the Problems]

In order to solve the above problems, the circuit of the present invention includes a video input terminal 1 for inputting a composite video signal CVS as shown in the first and second illustrations, and a receiver for receiving the composite video signal CVS input to the input terminal 1. 2 and the level of the video signal output from this receiver 2 is converted to a level that meets the specifications of the display device, and the video signal VD of the level is converted.
Level converter 3 for outputting the composite video signal to the display device and the composite video signal CVS input to the video input terminal 1 for separating the composite video signal and introducing it into the vertical and horizontal deflection circuits of the display device. And composite signal separation device 4 for outputting the composite sync signal CS
And a video display circuit 7 including a signal synthesizing device 5 for synthesizing the composite sync signal CS and the video signal VD, and a video output terminal 6 of the composite video signal CVS output from the synthesizing device 5, a plurality of display devices 8 ₁ It is configured by sequentially connecting ~ 8 _n .

[Action]

The composite video signal CVS is input to the video input terminal 1 of the video display circuit 7 connected to the display device 8 ₁ and received by the receiver 2 to output the video signal VD. The video signal VD is output to the display device 8 1. The video signal is input to the video signal input terminal of ₁ and displayed on the screen, and the video signal VD
Is input to the signal synthesizer 5.

On the other hand, composite video signal CVS is a composite signal from the composite video signal CVS is input to the composite signal separation device 4 is separated, the vertical outputs than this, the horizontal synchronizing signal VS, HS display device 8 ₁ vertical, horizontal deflection circuit Is input to the signal synthesizing device 5 after the composite sync signal (composed of vertical and horizontal sync signals) CS is separated.

Video signal VD and composite sync signal to the signal synthesizer 5.
CS is entered synthetic, composite video signal CVS to output from the video output terminal 6 is input to a video input terminal 1 of the video display circuit 7 connected to the next display device _82, are treated in the same manner as described above the display device ₈₂ the same screen display is performed, the above-described operation is the same screen display is performed sequentially performed one after another display device below Te.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a video display circuit which constitutes an embodiment of the circuit of the present invention, and FIG. 2 is a block diagram showing the overall configuration of the circuit of the present invention.

In the figure, 9 is a control unit for outputting a composite video signal CVS, and 10 is its video output terminal. 8 ₁ to 8 _n are a plurality of display devices, for example, a cathode ray tube (CRT), which display the same video screen. Reference numeral 7 denotes a video display circuit for displaying the same screen on these CRTs 8 ₁ to 8 _n.
The video output terminal 6 of the video display circuit 7 of the final display device 8 _n is connected to the video output terminal 10 of the control unit 9 by the connection cable 16 (maximum length 100 m) in series.
It is connected by a total connection cable 17 (there is no limit on the cable length).

The video display circuit 7 is, for example, a composite video signal.
Video input terminal 1 that inputs CVS, receiver 2 that receives the composite video signal CVS that is input to this input terminal 1, and level that converts the level of the video signal output from this receiver 2 to a level that conforms to the CRT specifications. Output of the converter 3, the first and second video extracting circuits 11 and 12 for inputting the video signal VD of the predetermined level output from the level converter 3 to the video signal input terminal of the CRT, and the first video extracting circuit 11. A buffer amplifier 13 for amplifying the video signal and a composite signal separating device 4 for separating the composite signal from the composite video signal CVS input to the video input terminal 1.
And vertical / horizontal synchronization signal extraction circuits 14 and 15 for extracting vertical / horizontal synchronization signals VS and HS from the composite signal output therefrom and outputting them to the vertical / horizontal synchronization circuit (not shown) of the CRT.
And the composite sync signal (composed of vertical and horizontal sync signals) CS and buffer amplifier which are also separated and taken out.
It comprises a signal synthesizing device 5 for synthesizing the video signals extracted from 13, and a video output terminal 6 of the composite video signal CVS output from the synthesizing device 5.

In the above configuration, the composite video signal CVS output from the video output terminal 10 of the control unit 9 is input to the video input terminal 1 of the video display circuit 7 of the CRT 8 ₁ and the receiver 2
And the video signal VD is output from the video signal VD. The video signal VD is transmitted via the first and second video extracting circuits 11 and 12 to C
The video signal VD output from the first video extraction circuit 11 is amplified by the buffer amplifier 13 while being input to the video signal input terminal of the RT8 ₁ for screen display, and the signal synthesizer 5
Entered in.

On the other hand, the composite video signal CVS is input to the composite signal separation device 4 and the composite signal is separated from the composite video signal VS, and the vertical signal output from this is output.
Horizontal sync signals VS and HS are vertical, horizontal sync signal extraction circuit 14,
Extracted by 15, CRT 8 ₁ vertical, is provided are input to a horizontal deflection circuit (not shown) on a screen stationary, and also the composite synchronizing signal CS is input is separated into the signal synthesizer 5.

Video signal VD and composite sync signal to the signal synthesizer 5.
CS is entered synthetic, composite video signal CVS to output from the video output terminal 6 is input to a video input terminal 1 of the video display circuit 7 connected to the next CRT 8 _2, this is processed in the same manner as described above CRT 8 ₂ same screen display is performed, the above-described operation is the same screen displayed sequentially performed one after another CRT is performed below.

Since a plurality of CRT8 ₁ to 8 _n displaying the same screen are sequentially connected by the video display circuit 7 connected to them, the number of CRT8 ₁ to 8 _n and the total connection cable 1
The length of 7 is not limited.

[Effect of device]

That is, according to the present invention, since a plurality of display devices 8 ₁ to 8 _n displaying the same screen are sequentially connected by the video display circuit 7 connected to them, the display devices 8 ₁ to 8 _n are The effect is that there is no restriction on the number of units and the length of the total connection cable 17.

[Brief description of drawings]

FIG. 1 is a block diagram of a video display circuit which constitutes an embodiment of the circuit of the present invention, and FIG. 2 is a block diagram showing the overall configuration of the circuit of the present invention. 1 ... video input terminal, 2 ... receiver, 3 ... level converter, 4 ... composite signal separating device, 5 ... signal combining device, 6 ... video output terminal, 7 ... video display circuit, 8 ₁ to 8 _n: Display device (CRT), CVS: composite video signal, VD: video signal, CS: composite sync signal, VS: vertical sync signal, HS: horizontal sync signal.

Claims (1)

[Scope of utility model registration request] 1. A video input terminal 1 for inputting a composite video signal CVS, a receiver 2 for receiving the composite video signal CVS input to this input terminal 1, and a level of a video signal output from the receiver 2 of a display device. Convert to a level that meets specifications and convert the video signal to that level
Level converter 3 that outputs VD to the display device, and vertical and horizontal synchronization signals VS and HS that separate the composite signal from the composite video signal CVS input to the video input terminal 1 and introduce it into the vertical and horizontal deflection circuits of the display device. And a composite signal separation device 4 for outputting a composite sync signal CS,
A plurality of display devices 8 ₁ to 8 are provided by a video display circuit 7 including a signal synthesizing device 5 for synthesizing the composite sync signal CS and the video signal VD, and a video output terminal 6 of the composite video signal CVS output from the synthesizing device 5. A connection circuit of a plurality of display devices configured to sequentially display _n and displaying the same screen.