JPH056393B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention comprises a plurality of video signal input terminals,
This invention relates to a television receiver that can be used not only to reproduce television images, but also to reproduce VTR images and as a terminal display device for a computer.

Conventional configuration and its problems In recent years, it has become common to have multiple video signal input terminals, and to one of these input terminals, for example, the playback signal of a VTR is added, and to the other one, the output signal of a VHD disc player is added. Therefore, there are television receivers on the market that can display respective reproduced images or can also be used as a display device for a computer terminal by connecting one of the input terminals to a computer. In such a receiver, the input signal is switched by using a mode changeover switch using a light touch switch to switch the control signal generated by the control circuit, and select one of the plurality of video signal inputs according to this control signal. The broadcast television signal is selected and output, and the broadcast television signal is selected by a selection signal generated when the power switch of the receiver is first turned on. Therefore, when you want to watch the playback images on a VTR, first turn on the power switch,
It is necessary to operate the mode selector switch again, and the image on the VTR cannot be viewed immediately after the power switch is turned on.

FIG. 1 shows an example of an input selection circuit of such a conventional receiver. In the figure, 1 is a control circuit composed of JK flip-flop circuits 1a and 1b, and a trigger pulse is given by a mode changeover switch (not shown), and output terminals 2 and 3 and 4 and 5 are alternately set to high level and low level. The configuration is such that control signals are output to these terminals. 6 is a signal switching circuit, 7 and 8 are signal switching circuits 6
The base of transistor 7 is connected to terminal 2 of flip-flop circuit 1a, and the base of transistor 8 is connected to terminal 4 of flip-flop circuit 1b. The signal switching circuit 6 has a plurality of input circuits 9a, 9b, and 9c into which at least three signals are input in accordance with the combinations of conduction states of the plurality of transistors 7 and 8, and each input circuit has a television antenna,
It is connected to the output of the VTR and the video signal circuit from the computer, and one of these input signals is selected and output to the output terminal 10.

Now, when the power switch of the receiver is turned on, terminals 2 and 4 of the control circuit 1 become high level, terminals 3 and 5 become low level, transistors 7 and 8 are both conductive (turned on), and the signal switching circuit 6 is turned on. The television signal from the antenna is selected and the receiver enters television mode. Next, when a pulse is given to the control circuit 1 by the mode changeover switch, the terminal 2 becomes a low level, the terminal 4 becomes a high level, the transistor 7 becomes cut off (off), the transistor 8 becomes an on state, and the switching circuit 6 becomes the VTR. selects the input signal from the receiver, and the receiver enters video mode. Then, when a pulse enters the control circuit 1, terminal 2 becomes high level, terminal 4 becomes low level, transistor 7 is turned on, transistor 8 is turned off, and signal switching circuit 6 selects the video signal from the computer. It is output to the output circuit 10 and becomes RGB mode.

As described above, conventional television receivers have the inconvenience that they always enter the television mode immediately after turning on the power switch, and cannot immediately view input signals other than television after turning on the power switch.

OBJECT OF THE INVENTION The present invention eliminates the above-mentioned inconveniences and provides a television receiver with a multi-input terminal that can arbitrarily set the first input signal to be selected when the receiver's power switch is turned on. The purpose is to provide

Structure of the Invention The present invention provides a changeover switch that changes the combination of connections between the output terminal of the control circuit and the transistor in the conventional circuit described above, and operates the changeover switch to generate a changeover signal immediately after turning on the power switch. The input signal circuit selected by the signal can be changed to a desired one.

DESCRIPTION OF THE EMBODIMENT FIG. 2 is a circuit diagram of an embodiment of the present invention. In the figure, parts that are the same as those in FIG. The difference from FIG. 1 is that an initial mode changeover switch 11 is connected between the output terminal of the control circuit 1 and the transistors 7 and 8.
The common terminal c is connected to the base of the switching transistor 7, and the first fixed terminal a is connected to the JK flip-flop circuit 1 constituting the control circuit 1.
A is connected to terminal 2 of flip-flop circuit 1b, and a second fixed terminal b is connected to terminals 4 and 5 of flip-flop circuit 1b via backflow prevention diodes 12 and 13.

In the above configuration, when the sliding piece d of the initial mode changeover switch 11 is connected between the terminals a and c as shown, the operation is similar to the conventional example shown in FIG. That is, when the power switch is turned on in this state, the control circuit 1 has terminal 2 at high level and terminal 4 at high level.
also becomes high level, transistors 7 and 8 are both conductive, signal switching circuit 6 selects the television signal, and the receiver enters television mode. and control circuit 1
The control signal (high level, low level) changes each time a pulse is applied to the signal switching circuit 6, and the output signal of the signal switching circuit 6 changes accordingly, switching from video mode to RGB mode, as explained in Figure 1. It's the same as what I did.

Next, when the sliding piece d of the initial mode changeover switch 11 is placed in the connection between the terminals b and c, the base of the transistor 7 is connected to the terminals 3 and 5 of the control circuit 1 through the switch 11 and further through the diodes 12 and 13. connected to. When the power switch is turned on in this state, terminals 3 and 5 are at low level and terminal 4 is at high level, transistor 7 is off and transistor 8 is on, and the signal switching circuit is switched to VTR.
outputs the signal and enters video mode. By connecting the initial mode changeover switch 11 between terminals b and c in this manner, the video mode can be set at the same time as the power switch is turned on. To switch the receiver to another mode, either connect the sliding piece d of the initial mode changeover switch 11 between a and c and apply a pulse to the control circuit with a mode changeover switch (not shown), or By applying a pulse to the control circuit while keeping the connection between b and c, it is possible to sequentially switch from video mode to television mode and further to RGB mode.

Effects of the Invention As described above, according to the present invention, between the control circuit having a plurality of output terminals that generate control signals and the plurality of transistors whose conduction is controlled by the control signals, the output terminal and the transistor By providing a changeover switch that changes the combination of connections, it is possible to select the first input signal to be output when the power switch is turned on, and to obtain an image in a desired mode at the same time as the switch is turned on.

[Brief explanation of drawings]

FIG. 1 shows an example of an input signal selection circuit in a conventional television receiver, and FIG. 2 shows a circuit according to an embodiment of the present invention. 1... Control circuit, 1a, 1b... JK flip-flop circuit, 2, 3, 4, 5... Control signal output terminal, 6... Signal switching circuit, 7, 8... Switching transistor, 9a to 9c... Input signal, 1
0... Output signal, 11... Initial mode selector switch, 12, 13... Backflow prevention diode.

Claims (1)

[Claims] 1. A device comprising a plurality of flip-flop circuits and a plurality of pairs of output terminals connected to each flip-flop circuit, and outputting each pair of control signals (high level, low level) to the plurality of pairs of output terminals. a control circuit; a plurality of transistors each connected to one of the plurality of pairs of output terminals and whose conduction state is controlled by the high-level or low-level control signal; One input signal is sequentially selected and outputted according to the control signal (high level, low level) from among a plurality of input signal circuits into which at least three or more signals are input corresponding to combinations of conduction states of transistors. and a plurality of transistors respectively connected to one terminal of each pair of output terminals of the plurality of pairs of output terminals of the control circuit; the television receiver is connected to the power supply by changing the combination of conduction states of the plurality of transistors whose conduction states are controlled in accordance with the control signal by operating the changeover switch; 1. A television receiver characterized in that an input signal circuit to be selected can be changed by a control signal that is first generated.