KR19990031764A - Video signal display device and control method thereof - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a broadcasting communication system for overlaying and outputting a television video signal currently output and another television video signal input from the outside. An external video mode detection unit (100) for detecting and generating a television carrier subcarrier of the external video signal so as to match the television method of the internal video signal to the television method of the external video signal; A microcomputer (200) for controlling the internal video signal and the external video signal to be overlaid according to the television method detected by the external video mode detector (100); An internal video providing unit (300) for outputting a video signal read from an internal storage area in accordance with a television method detected by the external video mode detection unit (100) under the control of the microcomputer (200); A D / A converter 400 for converting a digital video signal provided from the internal video provider 300 into an analog video signal; An RGB encoder (500) for encoding the analog signal converted by the D / A converter (400) in accordance with the television system detected by the external video mode detector (100); Different televisions comprising a switch unit 600 which operates under the control of the microcomputer 200 and selectively outputs the video signal output from the RGB encoder 500 and the video signal input from the outside. Video signal overlay apparatus and method thereof.

The present invention detects the television system of the video signal input from the outside, and overlays the television system of the video signal that is currently output according to the detected television system to display a clean video screen without distortion. .

Description

Video signal display device and control method thereof

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a broadcast communication system, and more particularly, to a video signal display apparatus for overlaying different video signals of NTSC scheme and PAL scheme and a control method thereof.

In general, a television system of a broadcast communication system includes NTSC (National Television System Committee), PAL (Phaser Alternation Line), SECAM (Sequential Couleur a Memoire). In the NTSC method, the system converts R, G, and B signals into one luminance signal (Y) and two chrominance signals (I, Q), and then has a frequency of 3.58 MHz in an image band with two chrominance signals. A subcarrier is modulated, and a complex signal obtained by adding a modulated color difference signal and a luminance signal is modulated and transmitted by a carrier having a higher frequency. In addition, the PAL method transmits a color subcarrier of 4.43 MHz as a color difference signal by performing quadrature two-phase modulation in addition to a luminance signal. A signal obtained by modulating one color difference signal is transmitted by inverting polarity for each scan line. The SECAM method alternately modulates the color subcarriers by two color difference signals for each scan line, and then transmits the modulated color difference signals by superimposing them on the luminance signal.

1 is a block diagram of a conventional video signal display apparatus.

As shown, a microcomputer 10 for controlling all operations required to display a video signal; An internal video providing unit (20) for reading a video signal from a storage device under the control of the microcomputer (10); A D / A converter (30) for converting the digital video signal provided from the internal video providing unit (20) into an analog video signal; An RGB encoder (40) for encoding the analog video signal converted by the D / A converter (30) into an RGB signal and outputting the composite video signal; The switch unit 50 operates under the control of the microcomputer 10 and selectively outputs a video signal through the RGB encoder 40 and a video signal from the outside.

The operation of the conventional video display device configured as described above is as follows.

First, under the control of the microcomputer 10, the internal video providing unit 20 reads a video signal such as JPEG, MPEG, etc. of NTSC format from the CD and provides it to the D / A converter 30. Then, the D / A converter 30 converts the NTSC video signal into an analog signal, and the RGB encoder 40 encodes the analog signal and outputs the composite video signal through the switch unit 50.

While the PAL video signal is input from the outside while the internal video signal is output in the NTSC system, the microcomputer 10 controls the switch unit 50 to overlay the internal video signal and the external video signal. Will print.

However, such a conventional video display device has a problem that the screen is distorted or the screen is broken when the NTSC-type internal video signal and the PAL-type video signal inputted from the outside are output.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems, and in particular, detects a video mode of an externally input video signal, and automatically converts a video mode of an outputted internal video signal to a detected external video mode. The present invention provides a video signal display device and a method of controlling the same, which outputs a clean screen by overlaying video signals of different video modes without distortion by outputting them in an external video mode.

The present invention to achieve the above object,

An external video mode detection unit for detecting a television system of the video signal input from the outside and generating a television carrier subcarrier of the external video signal to match the television system of the internal video signal to the television system of the external video signal; A microcomputer controlling the internal video signal and the external video signal to be overlaid according to the television system detected by the external video mode detector; An internal video providing unit for outputting a video signal read from a storage area in accordance with a television system detected by the external video mode detection unit under the control of the microcomputer; A D / A converter for converting a digital video signal provided from the internal video providing unit into an analog video signal; An RGB encoder for encoding the analog signal converted by the D / A converter according to the television system detected by the external video mode detector; A technical feature of the present invention is that the switch is configured to operate under the control of the microcomputer and selectively output the video signal output from the RGB encoder and the video signal input from the outside.

In order to achieve the above object, the present invention (method) is,

A television method determination step of detecting the synchronization of the video signal input from the outside to determine the television system of the video signal and checking whether the television system of the external video signal is different from the television system of the video signal currently being output; A television format conversion step of controlling the internal video signal to be converted into the television format of the external video signal if it is different from the television format of the internal video signal currently output in the determining step; The method is characterized in that the method comprises an output step of controlling the external video signal and the internal video signal converted by the television system to be overlaid and output.

1 is a block diagram of a conventional video display device;

2 is a block diagram of a video signal display device according to the present invention;

3 is a flowchart showing a video signal display control method according to the present invention;

<Explanation of symbols for main parts of the drawings>

100: external video mode detection unit 110: synchronous detector

120: subcarrier generator 200: microcomputer

300: Internal video provider 300: D / A converter

500: RGB encoder 600: switch

Hereinafter, the configuration and operation of an embodiment according to the technical spirit of the present invention "video signal display apparatus and control method thereof" will be described in detail with reference to the accompanying drawings.

<Example>

First, an embodiment configuration of a video signal display apparatus includes an external video mode detector 100 for detecting a video mode of a video signal input from the outside and generating a carrier of the external video mode as shown in FIG. A microcomputer (200) for controlling the overlay of the internal video signal and the external video signal according to the video mode detected by the external video mode detector (100); An internal video providing unit (300) for outputting a video signal read from a storage area in a video mode detected by the external video mode detecting unit (100) under the control of the microcomputer (200); A D / A converter 400 for converting a video signal provided from the internal video provider 300 into an analog signal; An RGB encoder (500) for encoding the analog signal converted by the D / A converter (400) in accordance with the video mode detected by the external video mode detector (100); The switch unit 600 operates under the control of the microcomputer 200 and selectively outputs the video signal output from the RGB encoder 500 and the video signal input from the outside.

The external video mode detector 100 includes: a synchronization detector 110 for detecting synchronization of a video signal input from the outside; The sub-carrier generator 120 generates a sub-carrier corresponding to the video mode detected by the sync detector 110.

Next, as shown in FIG. 3, the control method of the video signal display detects the synchronization of the video signal input from the outside to determine the television method of the video signal, and the video signal of which the television method of the external video signal is currently output. A television system determination step (ST10-ST13) for checking whether the television system differs from the television system; A television format conversion step (ST15-ST16) of controlling the internal video signal to be converted into the television format of the external video signal if it is different from the television system of the internal video signal currently output in the determination step (ST13); An output step ST17 is performed to control the external video signal and the internal video signal converted by the television system to be overlaid and output.

In the above-described television method determination step ST12, if the video synchronization signal of the video signal input from the outside is 60Hz, it is an NTSC video signal, and if it is not 60Hz, it is determined that it is a PAL video signal.

The operation and control method of the video signal display apparatus according to the present invention will be described as follows.

First, while the NTSC video signal is being output to the video display device, when the video signal is input from the outside to the sync detector 110 in the video mode detector 100 (ST10), the sync detector 110 detects the sync. The video synchronization signal is transmitted to the microcomputer 200. Then, the microcomputer 200 detects this video synchronization signal, and if the detection result is not 60Hz, the microcomputer 200 determines that the external video signal is a PAL video signal (ST12-ST13). If the video mode is different from the PAL video signal and the video signal of the internal video mode currently being output, the microcomputer 200 controls the internal video providing unit 300 to control the PAL of the video signal input from the outside. The internal video signal such as font data, JPEG, MPEG, etc. is provided to the D / A converter 400 in accordance with the scheme. Then, the D / A converter 400 converts the internal video signal received according to the PAL method into an analog video signal and delivers the same to the RGB encoder 500.

Meanwhile, the subcarrier generator 120 in the external video mode detector 100 generates a PAL subcarrier by the synchronization signal detected by the sync detector 110 and transmits the PAL subcarrier to the RGB encoder 500 (ST15).

Thus, the RGB encoder 500 transfers the video signal transmitted from the D / A converter 400 to the PAL subcarrier transmitted from the subcarrier generator 120 to make the internal video signal into the video mode of the video signal input from the outside. Encode (ST16). Then, the microcomputer 200 controls the switch unit 600 such that the internal video signal and the external video signal are overlaid at the position to be overlaid (ST17). Thus, the switch unit 600 selects and overlays the internal video signal output by the RGB encoder 500 according to the PAL method and the external video signal input by the PAL method from the outside under the control of the microcomputer 200. If a PAL video signal other than the NTSC method is input while the video signal is displayed in the NTSC method as described above, the NTSC video signal is automatically converted to the PAL method and overlaid. Thus, a clear video signal can be displayed without distortion.

As described above, the "video signal display apparatus and control method thereof" of the present invention particularly detects a television system of a video signal input from the outside, and detects a television system of a video signal currently being output. By overlaying them, the effect is to display a clear video screen without distortion.

Claims (4)

In the broadcast communication system for outputting by overlaying the video signal of the television system currently output and the video signal of another television system input from the outside, An external video mode detection unit 100 for detecting a television system of an input video signal from outside and generating a television carrier subcarrier of an external video signal so that the television system of an internal video signal can be matched to a television system of an external video signal; ; A microcomputer (200) for controlling the internal video signal and the external video signal to be overlaid according to the television method detected by the external video mode detector (100); An internal video providing unit (300) for outputting a video signal read from a storage area of an internal video signal in accordance with a television method detected by the external video mode detection unit (100) under the control of the microcomputer (200); A D / A converter 400 for converting a digital video signal provided from the internal video provider 300 into an analog video signal; An RGB encoder (500) for encoding the analog signal converted by the D / A converter (400) in accordance with the television system detected by the external video mode detector (100); A video signal, comprising a switch unit 600 that operates under the control of the microcomputer 200 and selectively outputs the video signal output from the RGB encoder 500 and the video signal input from the outside. Display device. The method of claim 1, wherein the external video mode detector 100, A synchronization detector 110 for detecting synchronization of a video signal input from the outside; And a subcarrier generator (120) for generating subcarriers corresponding to the television system detected by the sync detector (110). A method of overlaying and outputting a video signal of a television system currently being output and a video signal of another television system input from the outside, the method comprising: A television method determination step (ST10-ST13) that detects the synchronization of the video signal input from the outside to determine the television system of the video signal and checks whether the television system of the external video signal is different from the television system of the video signal currently being output. Wow; A television format conversion step (ST15-ST16) of controlling the internal video signal to be converted into the television format of the external video signal if it is different from the television system of the internal video signal currently output in the determination step (ST13); And an output step (ST17) of controlling the external video signal and the internal video signal converted by the television system to be overlaid and output. The method of claim 3, wherein the television system determination step (ST12), If the video synchronization signal of the video signal input from the outside is 60Hz NTSC video signal, if not 60Hz video signal display control method characterized in that it is determined.