JPS6382068A - Video signal switching device - Google Patents

Abstract

PURPOSE:To greatly increase the number of switching devices which are connected in parallel by passing an external control signal through the buffer circuit of an initial-stage video signal switch and connecting respective trailing- stage video signal switches in parallel. CONSTITUTION:Buffer circuits 14, 24, 34,..., 44 are provided additionally to respective video signal switches 10, 20, 30,..., 40 and input terminals of the buffer circuits 14, 24, 34,..., 44 are connected between control input terminals 11, 21, 31, and 41 and control interface circuits 12, 22, 32, and 42. Output signals are outputted at control buffer terminals 15, 25, 35, and 45. Only the control input terminal 11 of the initial-stage switch 10 is connected to an external controller 1 and the control input terminals 21, 31,..., 41 of trailing-stage switches 20, 30,..., 40 are connected to the control buffer terminal 15 of the buffer circuit 14 in parallel. Consequently, the load viewed from the control circuit 1 is only the initial-stage switch and switches which are squared times as many as before can be connected in parallel.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a video signal switching device for switching video signals to be transmitted on a large scale in a television studio transmission system.

[Conventional technology]

FIG. 3 shows the configuration of a conventional video signal switching device.

A conventional video signal switching device includes a plurality of video signal switchers 10.
20, 30. ...40 are combined to form a large-scale video signal switching device.

The control signal from the external control device 1 is transmitted to the control input terminals 11, 2 of each video signal switch 10, 20, 30, . . . , 40.
1, 31.degree. 41, and controls each video signal switching device 10, 20, 30, 40, forming a control system of a large-scale video signal switching device. The video signal switchers 10, 20, 30, and 40 have the same configuration, and each video signal switch is distinguished by an address. The control signals supplied in parallel to the external control input terminals 11, 21, 31.41 are transmitted to each control interface circuit 12, 22.
At 32.42, the address of each video signal switch is compared and the video Itami switching unit is controlled from the control interface circuit of the corresponding video signal switch.

[Problem that the invention seeks to solve]

Conventional control methods for video signal switching devices enable control of each video signal switching device by inputting control signals from an external control device in parallel to each video signal switching device as described above. There is a limit to the number of video signal switching devices that can be connected in parallel depending on the drive capacity of the device, and the limit is about a few, which limits the configuration of a large-scale video signal switching device.

An object of the present invention is to provide a video signal switching device that can significantly increase the number of video signal switching devices that can be connected in parallel, and that enables the construction of a large-scale video signal switching device.

[Means for solving problems]

The present invention includes a plurality of video signal switching devices including an external control device, a control interface circuit into which a control signal from the external control device is inputted through a control input terminal, and a video switching unit that switches video according to a command from the control interface circuit. A buffer circuit is provided in the first-stage video signal switching device among the plurality of video signal switching devices, the buffer circuit is connected to the external control device, and the output side of the buffer circuit is provided with a buffer circuit for each subsequent-stage video signal switching device. This is a video signal switching device characterized in that control input terminals are connected in parallel.

〔Example〕

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. As shown in FIG. 1, the present invention provides video signal switching devices 10, 20
, 30...40, buffer circuits 14, 24, 34
,...44 are additionally provided, and the control input terminals 11, 2
1, 31, 41 and control interface circuits 12, 22
, 32, 42, the buffer circuits 14, 24, 34
...44 input terminals are connected. An output signal is output to the control buffer terminal 15, 25° 35.45 of each buffer circuit. Only the control input terminal 11 of the first-stage video signal switching device 10 is connected to the external control device 1, and each of the subsequent-stage video signal switching devices 20, 30 . . . 40 control input terminals 21, 31 . . . 41 are connected in parallel to the control buffer terminal 15 of the buffer circuit 14 of the video signal switch 10. Other configurations are the same as before.

Therefore, the control signal from the external control device 1 passes through the buffer circuit 14 of the video signal switch 10 and controls each video signal switch 20, 30, 40 at the subsequent stage. In addition, video signal switch 1
0 is controlled without passing through the buffer circuit 14 as in the conventional example. Moreover, each buffer circuit 24, 34, 44 of the video signal switch 20, 30, 40 and the control buffer terminal 25°3
5 and 45 are left unused except for use as a first-stage video signal switch.

Here, the configuration of the large-scale video signal switching device according to the present invention will be explained with reference to FIG. In FIG. 2, there are blocks 200, 300, and 400 having the same configuration as the block 100 shown in FIG. 1, which shows one embodiment of the present invention. here,
The control input terminals 11 of the video signal switching devices 10 of each block 100, 200, 300, and 400 are connected to each other in parallel. The control signal from the external control device 1 is supplied to the control input terminal 11 of each first stage video signal switch 10 of each block 100, 200, 300, 400, and controls each video signal switch via the buffer circuit 14. do.

〔Effect of the invention〕

As described in detail above, the present invention is a large-scale video signal switching device that combines a plurality of video signal switching devices, in which a control signal from an external control device is passed through a buffer circuit of the first-stage video signal switching device, By connecting each video signal switcher in parallel, the load seen by the external control device is only the first-stage video signal switcher, making it possible to connect multiple first-stage video signal switchers in parallel, compared to conventional This makes it possible to perform parallel connections as many as the square of , and has the effect of configuring a large-scale video signal switching device in which 100 or more video signal switching devices are connected in parallel.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a video signal switching device according to the present invention, FIG. 2 is a block diagram for explaining the effects of the present invention, and FIG. 3 is a block diagram of a conventional video signal switching device. . 1... External control device, 10, 20, 30, 40...
Video signal switcher, 11, 21, 31, 41... Control input terminal, 12, 22, 32, 42... Control interface circuit, 13, 23, 33, 43... Video switching unit, 14, 24 , 34, 44... Buffer circuit, 15° 25. 35, 45... Control buffer output terminal, 100, 200, 300... Video signal switch block

Claims (1)

[Claims] (1) A plurality of video signal switching devices each including an external control device, a control interface circuit into which a control signal from the external control device is inputted through a control input terminal, and a video switching unit that switches images according to a command from the control interface circuit. A buffer circuit is provided in the first-stage video signal switching device among the plurality of video signal switching devices, the buffer circuit is connected to the external control device, and the output side of the buffer circuit is provided with a buffer circuit in the first-stage video signal switching device among the plurality of video signal switching devices. A video signal switching device characterized in that control input terminals are connected in parallel.