KR950020672A - Video signal switching circuit - Google Patents

Abstract

1. A video signal switching circuit applied to a video cassette tape recorder, comprising: first switching means for selecting and outputting any one of an output of the tune unit, an input signal of the external input unit, and an output signal of the deck A; A sync separator configured to detect a complex sync signal included in an image signal among the signals input through the first switching means, and output the split sync signal into a horizontal sync signal and a vertical sync signal; A pulse generator for receiving the horizontal synchronizing signal and the vertical synchronizing signal separated by the synchronizing separator and outputting the composite blanking signal and the composite synchronizing signal, respectively; A blank unit which outputs only a pure video signal by inputting a composite blanking signal and a video signal of the pulse generator; An inverting amplifier for inverting the video signal of the blank part and amplifying the video signal to a predetermined level; A mixing unit for mixing the inverted inverted video signal and the synthesized synchronization signal to output a complete video signal; Second switching means for selectively switching the video signal of the mixing unit and the non-inverted video signal of the first switching means to output to the monitor or to the deck B; An image signal switching circuit comprising a control unit for controlling the second switching means and the pulse generator is implemented. Therefore, by separating the image signal into a reverse signal and a non-inverted signal there is an advantage that can obtain a screen such as watching a photographic film when inverted.

Description

Video signal switching circuit

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

1 is a block diagram of a video signal switching circuit according to an embodiment of the present invention.

2 (a) and (d) are output waveform diagrams of respective parts of an image signal switching circuit according to an exemplary embodiment of the present invention.

Claims (3)

First switching means 20 for selecting and outputting only one of an output of a tuner, an input signal of an external input unit, and an output signal of deck A; A sync separator 60 for detecting a complex sync signal included in an image signal among the signals input through the first switching means 20 and separating the horizontal sync signal into a horizontal sync signal and outputting the sync signal; A pulse generator (70) for receiving the horizontal and vertical synchronization signals separated by the synchronization separation unit (60) and outputting the composite blanking signal and the composite synchronization signal, respectively; A blank unit 30 for outputting only the pure video signal by inputting the composite blanking signal and the video signal of the pulse generator 70; An inverting amplifier 40 for inverting and amplifying the video signal of the blank unit 30 to a predetermined level; A mixing unit 50 for mixing the inverted video signal of the inverted amplification port 40 with the synthetic synchronous signal to output a complete video signal; Second switching means (100) for selectively switching the video signal of the mixing section (50) and the non-inverting video signal of the first switching means (20) to output to the monitor or to the deck B; Image signal switching circuit, characterized in that consisting of a control unit 90 for controlling the second switching means 100 and the pulse generator 70, The video signal switching circuit according to claim 1, wherein the control unit (90) connects a mode switch to apply a control signal to the pulse generator (70) and the second switching means (100). The video signal switching circuit of claim 2, wherein the operation of all the switches is displayed on a display unit connected to a control unit output terminal. ※ Note: The disclosure is based on the initial application.