KR910008620Y1 - Video signal input circuit - Google Patents

Abstract

No content.

Description

Video signal input circuit for TTL and analog input signals

1 is a circuit diagram of the present invention.

2 is an operating waveform diagram according to the present invention.

FIG. 3a is an exemplary diagram of hybrid integrated circuit of the present invention, and FIG. 3b is an example of fixing FIG. 3a using a connector on a circuit board.

4 is a block diagram using the present invention in a monitor.

* Explanation of symbols for main parts of the drawings

1-3: Color signal input 4: Clamp signal input

5-7: Color signal output terminal 8: Blanking signal input terminal

9: ground 100-102: TTL logic circuit

110: level control circuit 400: TTL-analog converter

410: video drive 411: contrast control signal input terminal

420: video output circuit R _1- R ₁₂ : resistance

TR ₁ -TR ₈ : Transistor

The present invention relates to a video signal input circuit, and more particularly, to a video signal input circuit for a TTL and analog input signal used when an analog signal and a TTL (transistor-transistor longic) signal are input to the video signal input circuit of a monitor. will be. Conventionally, analog and TTL signals have been used in common using electronic switches or mechanical switches before video signal output stages. However, when using such circuits, contrast controls must be used for each analog and TTL video drive stages. Due to the price increase factor and the monitor for analog and TTL common use, even if the buyer only needs to use analog, the TTL circuit is built in, resulting in the problem of cost increase. . The present invention has been made to solve the above problems, a circuit for converting the input pulse of the TTL signal to the input pulse of the analog signal to the same as the input pulse of the analog signal blanking (Blanking) in advance to the blanking circuit Is a hybrid integrated circuit, and the converter uses a single part to avoid the complexity of the video circuit according to the analog and TTL signal input, and to facilitate the production and management problems. When described in detail as follows. FIG. 1 is a circuit diagram of the present invention, in which a collector is connected to a power supply terminal (B ⁺ ) or a transistor (TR ₁ -TR ₆ ) to which a collector is connected through a resistor (R ₁ -R ₃ ). 100-102), the configuration and the transistor _{(TR 1), (TR 3} ), include color signal (RED, GREEN, BLUE) is connected such that the input to the transistor (TR ₂ input terminal (1-3) of (TR ₅₎ ), (TR _4), (the base of TR _6), but connected to the emitter of the transistor (TR ₇₎ is connected through a resistor (R ₄₎ to the power source (B ⁺⁾ wherein the transistor (TR ₁ -TR ₆₎ respectively, The common emitter is connected to output the color signals R, G, and B to the output terminals 5-7 through resistors R ₇ , TR ₉ , and R ₁₁ , respectively.

A resistor connected to the transistor _{(TR 2), (TR 4} ), a transistor (TR ₇₎ a power supply (B ⁺⁾ to the base and collector of the transistor (TR7), (TR ₈₎ connected to the common base of the (TR ₆₎ The transistor TR ₈ receives a blanking pulse through the terminal 8 at the base and the emitter is connected to the ground terminal 9 through R ₅ and R ₆ . The collector of the transistor TR ₇ is configured to be connected to the output terminal 5-7 through resistors R ₈ , R ₁₀ , and R ₁₂ and to the ground terminal 9. The effect of these will be described below.

In the first, the respective color signals R, G, and B are applied to the input terminals 1-3 connected to the transistors TR ₁ , TR ₃ , and TR ₅ of the TTL logic circuits 100-102. As shown in the waveform C of FIG. 2, the transistors TR ₁ , TR ₃ , and TR ₅ act as a buffer and emitter follower, It is down by the voltage and is output to the emitters of the transistors TR ₁ , TR ₃ , and TR ₅ , and this output signal is divided by the time constant ratio by each of the resistors R _7- R ₁₂ to obtain an input terminal ( This output signal is divided by each resistance value in the state of blanking synthesis by transistors TR ₂ , TR ₄ , and TR ₆ , and the waveform d of FIG. Is output together. On the other hand, a blanking signal such as the waveform (a) of FIG. 2 is applied to the base of the transistor TR ₈ through the input terminal 8, and the transistor TR ₈ is saturated when the blanking signal is not blanking time. since the collector-down with bolts transistor (TR ₂₎ of the TTL logic circuits _{(100-102), (TR 4)} , (TR 6) because the voltage on the base takes the transistor _{(TR 2), (TR 4} ), ( TR ₆ ) is off.

The transistors TR ₂ , TR ₄ , and TR ₆ are turned off, and the color signals output through the resistors R7-R12 are output without a blanking pulse.

When the blanking signal is in the blank time, the transistor TR ₈ is turned off and biased by the values of the resistors R ₅ and R ₆ of the transistor TR ₇ during the period, so that the load resistance R ₄ is biased. Since a constant potential is applied, a constant potential is turned on even at the bases of the transistors TR ₂ , TR ₄ , and TR ₆ . When the transistors TR ₂ , TR ₄ , and TR ₆ are turned on, a blanking signal is output from the emitter terminal to be synthesized with the video signal, and the synthesized arc is divided voltage of each of the resistors R _7- R ₁₂ . By Down and output value through output terminal (5-7) Is output. The first circuit internal circuit output as described above is integrated into a hybrid integrated circuit as shown in FIG. 3A, and then embedded only when necessary as a package using a connector as shown in FIG. 3B, so that the video is as shown in FIG. By adding this circuit in front of the drive 410, the analog and TTL color signals can be used in common.

As described above, by adding a circuit of the present invention using an analog video circuit used in the prior art, it is possible to cope with analog and TTL signals in common, and in terms of price, it is possible to unify control circuits compared to other common circuits. In addition, with the integrated integrated circuit, the productivity and quality can be improved and the various requirements of the buyer's analog and TTL circuit can be satisfied by the card concept or the common concept.

Claims (1)

A circuit for processing a video signal by a TTL signal and an analog signal, comprising: transistors TR1 to TR6 and resistors R1 to R3, a TTL logic circuit for converting input TTL signals of R, G, and B into analog signals. Transistors TR7, TR8, and resistor R4, which are connected to 100-102 and the TTL logic circuits 100-102, are synthesized with the video signal according to the input of the clamp signal and the blanking pulse to output initial blanking. And a level adjusting circuit 110 connected to emitter terminals of the transistors TR1 to TR6 which are the TTL logic circuits 100 to 102, and consisting of resistors R7 to R12 to adjust the level of the analog output signal. Video signal input circuit for TTL and analog input signals.