JPH01315064A - Automatic video signal switching circuit - Google Patents

Abstract

PURPOSE:To omit the operation of a switch key by using a circuit which detects the working state of an external image generating device and performs the automatic switch to the video signal of said image generating generating device and preventing a user from being conscious of the actuation of a specific external image generating device. CONSTITUTION:The priority of preference is given to a VTR 1 or a VTR 2 that is actuated earlier. Then an external key is operated to acquire a VTR switch signal 15 when the switch is desired between both VTRs. Furthermore a detection control circuit 7 detects a VTR working state signal 4 if the operations of the VTRs are stopped in case a video signal 6 of the VTR 2 is presently shown on a TV signal switching circuit output signal 14 of the VTR 1 in the working states of both VTR 1 and VTR 2. Then a switch signal 8 is automatically switched and the video signal 5 of the VTR 1 is outputted to a VTR video signal switching circuit output signal 9 in its turn the signal 14. When both VTR 1 and 2 are stopped, the TV switch signal 13 of the VTR 1 of the circuit 7 is set in a TV state. Thus a TV signal 12 is outputted to the signal 14.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention can input signals from a plurality of external video generating devices such as VTRs. The present invention relates to video output devices such as televisions and monitors, and particularly relates to functions that can improve user-friendliness in a system that combines an external video generator and a video output device.

[Conventional technology]

In the conventional technology, only one video output device can be connected to an external video generator, and when the external video generator is in operation, it is possible to automatically display the video signal of the external video generator. However, in a video output device to which two or more external video generating devices can be connected, it is up to the user to select which external video generating device.

Related devices of this type include, for example, JP-A No. 5
An example of this is the channel selection device No. 8-88917.

[Problem to be solved by the invention]

In the above conventional technology, when two external video generating devices are connected to a video output device, each of them has Nα1. When the device number Nα2 is assigned and the external video generator becomes operational, first Nα
1 was selected, and the user had to perform a key operation to switch to 2. In such a case, first of all
There was an inconvenience that a key operation was always required to select Na 2 when only one of the two external video generators was in operation.
is being displayed on the video output device, if Nα1 is now stopped, the video output device will not display anything, and if the user wants to switch to N112, the user has to operate a key.

An object of the present invention is to automatically output Nα2 to the video output device when two external devices are connected to the video output device and only Nα2 is in an operating state. Further, when the two external video generating devices are in operation, when the external video generating device of Nal is stopped, the signal 2 is automatically output to the video output device. Another object of the present invention is to realize a function that allows the user to switch between the two external image generators by key operation only when the two external image generators are in operation.

[Means to solve the problem]

The above purpose is to incorporate into the video output device a circuit (automatic video signal switching circuit) that detects the operating state of the external video generator and automatically switches to the video signal of the external video generator that is in the operating state. This will be realized by

[Effect]

FIG. 2 shows a state transition diagram of the automatic video signal switching circuit of the present invention. Here, we will take as an example a video output device to which two external video generators can be connected, each with 301
．． #02 describes the equipment. Also, ON is the transition to the operating state (PLAY in the case of a VTR), and OFF is the stop state (PLAY).
In the case of VTR (7), the transition to 5TOP) is shown. Inside O is
Indicates the content being output by the video output device at that time 6
This figure shows that five states 1 to 5 exist.

16 is a reception signal of an internal tuner when the video output device is a television. Further, when the state is 19°20, the user can select a key operation.

The means to realize Figure 2 is to assemble it using logic circuits.

There are two ways to build it using microcontroller software.

By providing a circuit that holds the five states shown in FIG. 2, for example, if #01 turns ON from state 16, the state changes to state 17 and the contents of #01 are output to the video output device.
Further, if #02 turns ON from state 16, state 18 occurs, and the contents of #02 are output to the video output device.

Also, 301. If both #02 are ON or #01 is output in state 19, and #01 is turned OFF, the state becomes state 18 in which #02 is output.

Furthermore, in states 19 and 20, the user can switch between #01 and #02 as desired by a key operation.

6 [Embodiment] An embodiment of the present invention will be described below with reference to FIG. 1. In this figure, a 21-bin connector is used for the input section from the external video generating device, but the same applies to three or more.

This circuit consists of 21 bin connectors 1, 2. VTR video signal switching circuit 10. This is an example of a system configured with a VTRI television switching circuit 11 and a detection control circuit 7 that performs the state control shown in FIG.

Among the signal pins of the 21-pin connectors 1 and 2, those related to this circuit are the signal 3, which indicates the PLAY state of the VTR.
4 and video signals 5 and 6.

The detection control circuit 7 inputs these PLAY states 3 and 4,
If the VTR is in the PLAY state, the VTRI television switching signal 13 is set to the VTR side, and if the VTR in the operating state is a VTRI, the VTR switching signal 8 is set to the VTRI selection side.

As a result, the VTR video signal switching circuit output signal 9 becomes V
The same signal as TRI video signal 5 appears, and VTRI
The VTR video signal switching circuit output signal 9 appears in the television signal switching circuit output signal 14.

In addition, for VTRI and VTR2, the one that becomes operational sooner has priority until it stops operating, but if the user wants to switch the VTR (switch the priority) in the middle of the process, he/she can use the external key operation (remote control handset , local key, etc.)
The switching can be performed using the VTR switching signal 15.

Furthermore, VTRI and VTR2 are in the operating state and VTR2 is currently in operation.
If the video signal 6 of VTR1 appears in the TV signal switching circuit output signal 14, and the VTR stops operating, the detection control circuit 7 detects the VTR2 operating status signal 4 and switches the switching signal 8. , automatically outputs the VTRI video signal 5 to the VTR video signal switching circuit output signal 9 and, furthermore, to the VTRI television signal switching circuit output signal 14.

Further, when both the VTRI and the VTR2 are stopped, the VTRI television switching signal 13 of the detection control circuit 7 is set to the television state, so that the VTRI television signal switching circuit output signal 1
4, a television signal 12 is output.

〔Effect of the invention〕

According to the present invention, in a video output device to which two or more external video generating devices can be connected, it is possible to make the user aware of which external video generating device is in the operating state, and to connect the corresponding external video generating device. It is possible to eliminate the need for key vibrations to switch to .

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a state transition diagram of the detection control circuit of the present invention. 1...21 pin connector 1.2...21 pin connector 2.3...VTRITR status signal, 4...VTR
2 operating status signal, 5...VTRI video signal, 6...
- VTR2 video signal, 7... Operating state detection control circuit, 8... VTR switching signal, 9... VTR video switching circuit output signal, 10... VTR video signal switching circuit,
11...VTR1 television signal switching circuit, 12...TV signal, 13...VTRI television switching signal, 14.
...VTR1 TV switching circuit output signal, 15...External VTR switching signal, 16...Video output device internal signal output state, 17...Video output device #01 output state 1 (3
020FF), 18-...Video output device #02 output status 1 (8010FF), 19...Video output device #01
Output status 2 (#02ON), 20...Video output device #
02 output status 2 (301ON). Akira 7th/2

Claims (1)

[Claims] 1. A video output device to which a plurality of external video generating devices such as VTRs can be connected, including an input section for a video signal and an external device operating state signal, and a video switching section for switching video input signals from a plurality of external devices; If the video output device itself has a video source, the switching section between its internal video signal and the output from the video switching section, the control signal generation circuit for the video switching section manually operated by the user, and the operating status of the external device. 1. An automatic video signal switching circuit for a video output device, comprising a circuit that determines which external device is operating from a signal representing the video output device and automatically switches the external video generating device.