JP2001008115A - Television receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently select an input mode desired by a user by detecting a synchronizing signal form each external input terminal in the case of switching the input mode and controlling a switching circuit so as to skip the external input terminal when no synchronizing signal is obtained from the input terminal. SOLUTION: The television receiver is provided with a changeover circuit 6 that detects presence of input of a video signal to each of external input terminals 2, 3, 4 and has a function on a menu by which a user can set the presence of input of the video signal to each external input terminal. The changeover circuit 6 detects the presence of the synchronizing signal at the external input terminals 2, 3, 4 in the case of selecting an input mode and gives its information to a microcomputer 11. As a result, the control microcomputer 11 uses a control signal 12 to control the changeover circuit 6 in the case of switching the input mode and skips the external input terminals with absence of the synchronizing signal and outputs a signal of the input terminal with the synchronizing signal to a video output terminal 7. Thus, the object input mode can be selected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television receiver having a function of efficiently switching the input mode to a device desired by a user when many externally connected devices are connected to the television receiver (international patent classification). H04N
5/44).

[0002]

2. Description of the Related Art In recent years, the number of externally connected devices (for example, VTR, LD, DVD, game, DVC, MN converter, MUSE-LD, etc.) to a television receiver has increased. Those equipped with many external input terminals are increasing rapidly. When switching to a desired input mode, the user generally performs a toggle-type sequential switching operation. For example, one described in JP-A-5-207386 is known. In a television receiver having this function, there is a circuit (for example, a circuit for detecting the presence or absence of a synchronization signal of a video signal) for each external device connection terminal for detecting the presence or absence of a video signal. In some cases, the input terminal is controlled to be skipped when the input mode is switched depending on the presence or absence of a video signal.

[0003]

As described above, it is necessary to provide a circuit for detecting the presence or absence of a video signal for each external input terminal. Therefore, a circuit for detecting the presence or absence of a video signal by the number of external input terminals is required, which is inefficient in terms of the circuit scale and the number of components. Since the number of devices externally connected to the television receiver is expected to increase more and more in the future, it is not efficient to provide a circuit for detecting the presence or absence of a video signal for all the external input terminals.

[0004]

In order to solve the above-mentioned problems, in a television receiver according to the present invention, a switch is provided at a video terminal of an external input terminal. This makes it possible to detect the connection of the input terminal. In addition, external input terminals that the user has already connected to external devices, or external input terminals that are not always connected but will be used with considerable frequency, are set in advance for each input terminal on the menu screen. Set whether to connect an external device. This allows the user to freely select the input terminal, and the control microcomputer can easily detect the connection status, control the switching circuit based on the result, and automatically control only the input terminal to which the external device is connected. Can be sequentially switched by a toggle method.

A video signal input from an external input terminal is always input to AVSW, and a desired signal is selected and output by AVSW. In this AVSW, for each video input,
Alternatively, a function for detecting the presence or absence of a video signal is provided for the video output, and the control microcomputer can switch the AVSW while recognizing the presence or absence of the video signal based on this information.

According to the present invention, there is provided a television receiver having a function capable of efficiently switching to an input mode desired by a user.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A television receiver according to a first aspect of the present invention detects a synchronizing signal for each external input terminal when switching input modes, and sends information on the presence or absence of a synchronizing signal to a control microcomputer. If there is no synchronization signal to be transmitted, the switching circuit is controlled so as to skip the external input terminal, whereby it is possible to sequentially switch by a toggle system.

In the television receiver according to a second aspect of the present invention, the presence or absence of connection of each external input terminal is determined by providing a mechanical switch on the video signal terminal and turning the switch ON and OFF (the terminal has a pin). If stuck, ON [L: low],
OFF [H: High] if not stabbed, detects the presence or absence of connection of each external input terminal, and can only switch the connection of external input terminal only with the toggle method in sequence and can switch to the desired input mode efficiently. Become.

According to a third aspect of the present invention, in the television receiver, the video signal input from the external input terminal is an AV signal.
The signal is input to SW, the desired signal is selected by AVSW and output. The AVSW has a function of detecting the presence or absence of a video signal for each video input or video output, and the control microcomputer uses the detection information of the presence or absence of the video signal from the AVSW when switching the input. In addition, it is possible to skip and switch the input terminal having no video signal. Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. In the embodiments, the same reference numerals are used for the same components, and the description is omitted.

(Embodiment 1) FIG. 1 is a block diagram showing the configuration of a television receiver according to Embodiment 1 of the present invention.

In FIG. 1, 1 to 5 are input terminals (2 to 4 are external input terminals) of respective video signals, 6 is a switching circuit, 7 is a video output terminal, and 8 to 10 are synchronization detection circuits of each external input terminal. , 1
1 is a control microcomputer, and 12 is a control signal of the switching circuit 6.

Next, the operation of the above configuration will be described.
When the input mode is switched, the presence or absence of a synchronization signal at the external input terminals 2, 3, and 4 is detected, and the information is transmitted to the control microcomputer. From this result, the control microcomputer controls the switching circuit 6 with the control signal 12 when switching the input mode, skips the external input terminal without the synchronization signal, and outputs only the input terminal with the synchronization signal to the video output terminal 7. I do. This makes it possible to switch to the desired input mode.

(Embodiment 2) FIG. 2 is a block diagram of a television receiver according to Embodiment 2 of the present invention. In FIG. 2, S2 to S4 denote connection detection switches of external input terminals, and 13 denotes a connection detection switch. This is a state detection circuit. Next, the operation of the above configuration will be described. The ON / OFF data of the connection detection switches S2 to S4 is input to the state detection circuit 13 for the presence or absence of the external device connection of the external inputs 2, 3, and 4. The control microcomputer 11
The state of the state detection circuit 13 is read, and when the input is switched, only those having an external input connection are sequentially switched by a toggle method.

Thus, the state of the externally connected device can be automatically detected, and efficient input switching can be performed.

(Embodiment 3) FIG. 3 is a block diagram showing a configuration of a television receiver according to Embodiment 3 of the present invention. In the switching circuit 6, as for the external inputs 2, 3 and 4, the presence or absence of a video signal is always detected because the video detection circuit is provided in the circuit of 6. At the time of input switching, the control microcomputer can control such that an external input having no video signal is automatically skipped based on the information.

[0016]

As described above, according to the present invention, in a television receiver equipped with many external input terminals,
A switch is provided for detecting the presence or absence of connection with respect to the video signal of each external input terminal, and also has a function of allowing the user to set whether or not there is connection to each external input terminal on the menu screen. In addition, by adding a function to detect the presence or absence of video to the AVSW input or output that always receives the video signal input from the external input terminal, the user can quickly switch to the desired input mode Is provided.
In addition, in addition to these functions,
It is needless to say that the effect can be obtained from the viewpoint of reducing the circuit size and the number of components.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram of a television receiver according to Embodiment 1 of the present invention.

FIG. 2 is a circuit configuration diagram of a television receiver according to Embodiment 2 of the present invention.

FIG. 3 is a circuit configuration diagram of a television receiver according to Embodiment 3 of the present invention.

[Explanation of symbols]

 Reference Signs List 1 TV video signal input 2 External input (video 1) 3 External input (video 2) 4 External input (video 3) 5 Satellite broadcast video signal input 6 Switching circuit (AVSW) 7 Video signal output 8 Sync detection circuit (video 1) Reference Signs List 9 synchronization detection circuit (video 2) 10 synchronization detection circuit (video 3) 11 control microcomputer 12 control signal 13 state detection circuit

Claims (2)

[Claims] When switching an input mode, the presence or absence of a synchronization signal is detected for each external input terminal. If there is no synchronization signal, the external input terminal is controlled to be skipped and sequentially switched by a toggle method. Television receiver. 2. A mechanical switch is provided at a video terminal of each external input terminal to detect the presence / absence of connection of an external device, and the channel selection microcomputer can grasp the connection status of the external device based on the detection result and automatically connect. 2. The television receiver according to claim 1, further comprising a function capable of sequentially switching only the input mode in a toggle manner.