KR960033021A - Clamp signal automatic switching circuit - Google Patents

Abstract

The present invention detects the input of the vertical synchronization signal applied to the monitor and indirectly determines whether the synchronization signal is synthesized in the video signal, thereby automatically changing the trigger position of the clamp signal, regardless of the state of the synchronization signal. The present invention relates to a circuit for automatically cutting a clamp signal, which can always amplify a video signal.

According to an exemplary embodiment of the present invention, a pulse detection unit (100) for determining the presence or absence of a vertical synchronization signal input through the vertical synchronization signal input unit (70), and an output signal of the pulse detection unit (100) A pulse converting unit 110 for combining the output signal of the horizontal synchronizing signal output unit 60 to output the polarity of the output waveform in the positive or negative polarity according to the presence or absence of the input vertical synchronizing signal, and the pulse converting unit 110. A clamp signal output unit 120 for generating a clamp signal triggered in the back porch or the front porch of the output waveform of the pulse conversion unit 110 according to the output of the).

Accordingly, the present invention automatically converts the clamp signal to start at the front porch of the synchronous signal when the vertical synchronous signal is input according to the presence or absence of the vertical synchronous signal, and starts at the back porch of the synchronous signal when there is no input of the vertical synchronous signal. By stabilizing the amplification of the video signal, the reception range of the monitor is widened, and a stable screen can be reproduced. In addition, compared to the conventional, the circuit configuration has a useful effect of reducing the cost.

Description

Clamp signal automatic switching circuit

Since this is an open matter, no full text was included.

2 is a block diagram of a clamp signal automatic switching circuit according to the present invention.

Claims (4)

The image synthesis synchronization signal separating unit 20 which separates only the synchronization signal from the image synthesis synchronization signal output through the image synthesis synchronization signal input unit 10 and the horizontal input through the horizontal (horizontal / vertical) synchronization signal input unit 30. Alternatively, a synchronization signal selector 40 for selecting and outputting a horizontal / vertical synthesis synchronization signal and an image synthesis synchronization signal output through the image synthesis synchronization signal separation unit 20 and the synchronization signal selection unit 40. A horizontal / vertical synchronous signal separator 50 for separating and outputting the output synchronous signal into a horizontal / vertical synchronous signal, and a horizontal for outputting a horizontal synchronous signal through the output signal of the horizontal / vertical synchronous signal separator 50. The synchronous signal output unit 60 and the synchronous signal input through the vertical synchronous signal input unit 70 and the synchronous signal output through the horizontal / vertical synchronous signal separation unit 50 are selected to enable the vertical synchronous signal output unit 90. Vertical sync signal output to) In the monitor circuit including a unit 80, the pulse detection unit 100 for determining whether the vertical synchronization signal input through the vertical synchronization signal input unit 70 and the pulse detection unit 100 A pulse converter 110 for combining the output signal and the output signal of the horizontal synchronous signal output unit 60 to output the polarity of the output waveform in the positive or negative polarity according to the presence or absence of the input vertical synchronous signal, and the pulse conversion The clamp signal further comprises a clamp signal output unit 120 for generating a clamp signal triggered by the back porch or the front porch of the output waveform of the pulse converting unit 110 according to the output of the unit 110. Automatic switching circuit. According to claim 1, wherein the pulse detection unit 100 is connected to the power supply terminal (VCC) to the clear terminal (CLR), the input terminal (A) operating by recognizing the pulse in the falling paper is grounded, the pulse in the rising paper The input terminal (B) operating by recognizing the signal is connected to the output terminal of the vertical synchronous signal input unit 70, and the input terminal (C) (RC) is connected to the resistor R1 and the capacitor C1, which are time constants, are connected and connected. A clamp signal automatic switching circuit comprising a vibrator (MV1). According to claim 1 or 2, wherein the pulse conversion unit 110, one input terminal is connected to the inverting output terminal Q2 of the multivibrator MV1 of the pulse detection unit 100, the type force stage is the horizontal synchronization Clamp signal automatic switching circuit, characterized in that consisting of an exclusive o-gate (EX-OR1) connected to the output terminal of the signal output unit (60). According to claim 1 or claim 3, wherein the clamp signal output unit 120 is a clear end (CLR) and the input terminal (B) operating in the rising paper connected to the power supply terminal (VCC), the input terminal operating in polling paper (A) is connected to the output terminal of the exclusive o-gate EX-OR1 of the pulse converting unit 110, and a resistor R2 and a capacitor C2, which are time constants, are coupled to the input terminal C and RC. Clamp signal automatic switching circuit, characterized in that consisting of a multi-vibrator (MV2). ※ Note: The disclosure is based on the initial application.