KR940000657Y1 - Three different video singals selection apparatus for tv receiver - Google Patents

Abstract

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Description

3RF signal selection circuit

1 is a circuit diagram of the present invention.

2 is a diagram showing the output of the microcomputer and the RF signal selection state.

* Explanation of symbols for main parts of the drawings

10: micom 20, 30: relay

Q1, Q2: Transistors D1, D2: Diode

The present invention relates to a 3RF signal selection circuit that selects one RF signal from three RF input signals when receiving an external RF signal input and selecting one of the RF signal inputs and applying the same to a tuner. Applied to TV, it is used to simply select one RF signal.

External connection devices that use the RF input terminal of the TV are becoming more diverse, such as cable TV, VCR, computer, TV game machine, and VDP (Video Disk Player). Currently, only one RF input terminal or two TV receivers are installed. Since there are many external devices, the connection status of the RF input terminal had to be changed.

In other words, due to the large increase in the number of external connection devices, the RF input terminal of the existing TV receiver cannot be accommodated at all. Therefore, the connection status of the RF input terminal must be changed every time a single connection device is used. This is also a problem that can not be connected to more than two connections.

In view of the above, the present invention can be connected to many external devices without changing the connection state of the RF input terminal by configuring three RF input stages of a TV receiver and selecting only one RF signal among three RF input signals. The present invention is to provide a 3RF signal selection circuit that can simply select a single RF input signal, the present invention has a micom to recognize the RF selection key input and output the RF selection signal, the drive is driven by the RF selection signal of the micom The transistor is selected.

Thus, the present invention for selecting one of the three RF input signal based on the present invention in detail as follows.

The present invention recognizes the selection input of the RF input selection key input by the user and outputs the RF selection logic signal to the terminal (P1) (P2) and the output from the terminal (P1) of the micom (10) The transistor Q1 which is controlled to be driven by the selected RF selection logic signal and the relay coil is selected by the driving of the transistor Q1 to select one of the RF inputs RF2 and RF3. 20, the transistor Q2 whose driving is controlled by the RF selection logic signal output from the terminal P2 of the microcomputer 10, and the operation of the relay coil by the driving of the transistor Q2 are selected. It is composed of a relay 30 for selecting one RF input of the RF input (RF1) and the RF input selected from the relay 20 to be applied as an input signal of the tuner.

At this time, the diodes D1 and D2 are for protecting the counter electromotive force of the relays 20 and 30.

The RF input state selected by the RF selection signal level of the microcomputer 10 is shown in the table of FIG.

In the present invention configured as described above, when the user presses the RF input selection key of the remote controller, the microcomputer 10 recognizes this and outputs the RF selection logic signal level to the terminals P1 and P2. When the RF input RF1 is selected, (P1) (P2) is set to the mode low level. When selecting RF input (RF2), terminal P1 is at low level and terminal P2 is at high level. When selecting RF input (RF3), terminal P1 is selected. (P2) is all high level.

Each time the RF input selection key of the remote controller is pressed once, the above-mentioned RF selection signal is changed by one step and outputted.

In other words, press the RF selection key on the remote control once to select the RF input (RF1), press again to select the RF input (RF2), and press once to select the terminal (P1) (P2) of the microcomputer 10 so that the RF input (RF3) is selected. To control the output.

First, let's look at selecting the RF input (RF1).

At this time, since the low level is output from the terminals P1 and P2 of the microcomputer 10 to 'turn off' the transistors Q1 and Q2, the relays 20 and 30 do not operate the relay coil ( The relay coils 20 and 30 are not operated so that the relays 20 and 30 maintain their initial state.

Here, the initial state of the relay 20 is a state in which terminals (b) and (c) are connected, and the initial state of the relay 30 is in a state in which terminals (e) and (f) are connected.

Therefore, the RF input RF1 is selected because only the RF input RF1 is applied to the tuner.

Next, let's look at selecting the RF input (RF2).

In this case, a low level is output from the terminal P1 of the microcomputer 10 and a high level is output from the terminal P2, so that the transistor Q1 is 'turned off' and the transistor Q2 is 'turned on'.

When the transistor Q1 is 'turned off', the relay 20 is in an initial state, and the terminals b and c are connected. When the transistor Q2 is 'turned on', the relay coil of the relay 30 is operated. The relay 30 is in a state where the terminals d and e are connected.

At this time, terminals (a) and (b) of the relay 20 are in an 'off' state, and terminals (e) and (f) of the relay 30 are also in an 'off' state.

Therefore, since the RF input RF2 is input to the tuner inside the TV, the RF input RF2 is selected.

On the other hand, look at when selecting the RF input (RF3).

At this time, all of the terminals P1 and P2 of the microcomputer 10 output a high level so that the transistors Q1 and Q2 are 'turned on', and when the transistors Q1 and Q2 are 'turned on', the relay 20 The relay coil of (30) is operated so that terminals (a) (b) and terminals (d) (e) are respectively connected.

Therefore, the RF input RF3 is inputted to the tuner inside the TV through the reel 20 terminal (a) (b) and again through the relay 30 terminal (d) (e). RF3) can be selected.

As shown in FIG. 2, the RF inputs RF1, RF2, and RF3 are selected according to the output states of the terminals P1 and P2 of the microcomputer 10 changed by the RF input selection key of the remote controller. As it is.

As described above, the present invention allows one of the three RF input signals to be output by selecting one of the RF signals with a remote controller, and thus, the external input device can be used and the RF input can be easily selected.

Claims (1)

The microcomputer 10 recognizes the selection input of the RF input selection key and outputs an RF selection logic signal to the terminals P1 and P2, and the RF selection logic signal output from the terminal P1 of the microcomputer 10. A transistor Q1 in which driving is controlled, a relay 20 in which an operation of a relay bean is selected by driving the transistor Q1, and a relay 20 for selecting one RF input from an RF input RF2 or an RF3; The driving of the transistor Q2 is controlled by the RF selection logic signal outputted from the terminal P2 of the terminal P2 and the operation of the relay coil is selected by the driving of the transistor Q2 so that the RF input RF1 and the relay ( 20. A 3RF signal selection circuit comprising a relay 30 for selecting one RF input among the RF inputs selected in 20) and applying it as an input signal of a tuner.