KR940004957Y1 - Luma/chroma signal separation for multi tv system - Google Patents

Abstract

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Description

Luminance and color separation circuit capable of processing two broadcasting methods

1 is a luminance and color separation circuit diagram of a conventional NTSC broadcasting system.

2 is a luminance and color separation circuit diagram capable of processing two broadcasting methods according to the present invention.

* Explanation of symbols for main parts of the drawings

10, 20: NTSC and PAL signal processing circuit 11: NTSC comb filter

12, 22: filter circuit 12a, 22a: BPF1, BPF2

21: PAL comb filter DL1-DL4: Delay line

SW1 to SW3: Switch 100: Intermediate frequency processor

200: V / C demodulation circuit

The present invention relates to color television, and more specifically, to enable brightness and color separation of the National Television System Committee (NTSC) and Phase Alternation By Llne (PAL) broadcasting systems according to the switching under the control of the microcomputer. The present invention relates to a luminance and color separation circuit capable of processing various kinds of broadcasting methods.

In general, in the countries of the East, such as Korea and Japan, the NTSC broadcasting system is used as the standard method of television, so the luminance and color separation circuits are to follow.

That is, the luminance and color separation circuit of the conventional NTSC broadcasting system as shown in FIG. 1 is used. The processing is as follows.

First, luminance and color separation are performed through the intermediate frequency processor 100 and then through signal processing based on an NTSC comb filter.

However, at this time, crosstalk is generated between luminance signal and color signal in luminance and color separation in comb filter, and unnecessary noise is generated. Inconsistently, the luminance and color separation processing of PAL broadcasting method similar to that of NTSC was impossible.

This invention aims to solve these problems, and the purpose of this invention is to reduce noise and color separation in luminance and color separation, and to enable luminance and color separation of NTSC and PAL broadcasting. It is to provide a separate circuit.

Features of the invention to achieve this purpose, in the video signal processing circuit, connected to the intermediate frequency processor switch for selecting NTSC and PAL broadcasting method according to the control logic of the microcomputer, NTSC and PAL in accordance with the switching of the switch NTSC and PAL signal processing circuit for signal processing, a delay line connected to the NTSC and PAL signal processing circuit to match the timing of the luminance signal and the color signal, and a microcomputer connected to the delay line and the NTSC and PAL signal processing circuit. There is provided a luminance and color separation circuit capable of processing two broadcasting methods, which are composed of a control logic and a switch in which the luminance signal and the color signal of NTSC and PAL broadcasting are switched separately according to the switching state of the switch.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

2 is a luminance and color separation circuit diagram capable of processing two broadcasting methods according to the present invention. The switch SW1 selects the NTSC and PAL broadcasting methods according to the control logic ⓒ of the microcomputer in the intermediate frequency processor 100. Connect it.

The switch SW1 is connected to the NTSC and PAL signal processing circuits 10 and 20 which perform NTSC and PAL signal processing according to the switching of the switch SW1.

The NTSC signal processing circuit 10 includes an NTSC comb filter 11 for comb filtering an NTSC signal, and a filter circuit 12 for band filtering the NTSC signal.

The filter circuit 12 includes a trap circuit 12a for absorbing and attenuating components other than the required frequency components of the 3.58 MHz band of the NTSC signal and the 3.58 MHz band of the NTSC signal. A 3.58 MHz band pass filter BPF1 is passed through.

The PAL signal processing circuit 20 includes a PAL comb filter 21 for comb filtering the PAL signal and a filter circuit 22 for band filtering the PAL signal, and the filter circuit 22 is a color part of the PAL signal. A trap circuit 22a for absorbing and attenuating components other than the required frequency components of the 4.43 MHz band, which is the carrier signal frequency, and the 4.43 MHz bandpass filter (BFP2), which passes the signal components of the 4.43 MHz band, which is the color carrier signal frequency of the PAL signal. It is composed.

In addition, delay lines DL1 to DL4 are connected to the NTSC and PAL signal processing circuits 10 and 20 to match the timing of the luminance signal and the color signal.

The delay lines DL1 to DL4 and the NTSC and PAL signal processing circuits 10 and 20 according to the switching states of the control logics ⓐ, ⓑ and the switch SW1 of the microcomputer are NTSC and The switch (SW2) and (SW3) for switching the luminance signal and the color signal of the PAL broadcast method are connected separately.

In addition, the switches SW2 and SW3 have a video / chroma demodulation circuit 200 for demodulating the luminance and color signals separated through the switches SW2 and SW3. Connect it.

In the above configuration, the composite video signal output from the intermediate frequency processor 100 is switched at the switch SW1 according to the control logic ⓒ of the microcomputer.

At this time, if the control logic (©) value of the microcomputer is "high", the switch SW1 is switched to the "1" terminal to enter the NTSC processing mode. Therefore, the composite video signal through the switch SW1 is connected to the NTSC comb filter 11 and the filter. It is simultaneously input to the circuit 12.

Here, the signals input to the NTSC comb filter 11 and the filter circuit 12 are connected to the terminals ③ and ⑦ of the switches SW2 and SW3 when the values of the control logics ⓐ and (ⓑ) of the microcomputer are “ψψ”. The signal from the NTSC comb filter 11 is separated into a luminance signal and a color signal, input to the V / C demodulation circuit 200, and processed.

If the control logic (ⓐ) and (ⓑ) of the Hanfun and the microcomputer are " ψ1 ", the video signals through the filter circuit 12 are connected to the ④ and ⑧ terminals of the switches SW2 and SW3 so that the luminance signal and the color are mixed. Separated by signal.

Further, when the control logic (Y) value is logic " low ", the switch SW1 is switched to terminal < RTI ID = 0.0 > 2 < / RTI > to enter the PAL signal processing mode.

Accordingly, the composite video signal from the intermediate frequency processor 100 is simultaneously input to the PAL comb filter 21 and the filter circuit 22.

Here, the signals input to the PAL comb filter 21 and the filter circuit 22 are processed according to the control logics (ⓐ) and (ⓑ) of the microcomputer, and if it is "1ψ" like the control logics (ⓐ) and (ⓑ), ⑤ and ⑨ terminals of the switches SW2 and SW3 are connected so that the signal from the PAL comb filter 21 is separated into a luminance signal and a color signal.

When the control logic (ⓐ) and (ⓑ) values are " 11 ", they are connected to the ⑥ and ⑩ terminals of the switches SW2 and SW3 so that the composite video signal through the filter circuit 22 is separated into a luminance signal and a color signal. And input to the V / C demodulation circuit 200 to be processed.

As described above, this design selects NTSC and PAL broadcasting processing modes by controlling switch SW1 with the control logic ⓒ of the microcomputer, and switches SW2 and SW3 with the control logics ⓐ and ⓑ of the microcomputer. ) To separate the luminance signal from the color signal.

As described above, Ioan is a multi-system system that can separate the luminance signal and the color signal corresponding to NTSC and PAL broadcasting modes, and separates the luminance and color signals using switching. Since it does not occur, there is an effect of reducing the chance of noise generation.

Claims (5)

In the video signal processing circuit, a switch SW1 connected to the intermediate frequency processor 100 to select NTSC and PAL broadcasting schemes according to the control logic ⓒ of the microcomputer and NTSC and PAL according to the switching of the switch SW1. The delay line DL1 connected to the NTSC and PAL signal processing circuits 10 and 20 for signal processing and matching the timing of the luminance signal and the color signal by being connected to the NTSC and PAL signal processing circuits 10 and 20. ) To (DL4), the delay lines (DL1) to (DL4), and NTSC and PAL signal processing circuits (10) and (20) to control logic (ⓐ), (ⓑ) and switch (SW1) of the microcomputer. A luminance and color separation circuit capable of processing two broadcasting methods, consisting of a switch (SW2) and a switch (SW3) in which the luminance signal of the NTSC and PAL broadcasting method and the color signal are switched separately according to the switching state. The NTSC signal processing circuit (10) according to claim 1, wherein the NTSC signal processing circuit (10) comprises two NTSC comb filters (11) for comb filtering NTSC signals and a filter circuit (12) for band filtering the NTSC signals. Brightness and color separation circuits. 3. The filter circuit (12) according to claim 2, wherein the filter circuit (12) includes a trap circuit (12a) for attenuating components other than the required frequency components of the 3.58 MHz band, which is the color carrier signal frequency of the NTSC signal, and 3.58, which is the color carrier signal frequency of the NTSC signal. 2. A luminance and color separation circuit capable of processing two broadcast methods, consisting of a 3.58 MHz band pass filter (BPF1) that passes signal components in the MHz band. 2. The PAL signal processing circuit 20 according to claim 1, wherein the PAL signal processing circuit 20 includes two PAL comb filters 21 for comb filtering the PAL signals and a filter circuit 22 for band filtering the PAL signals. Brightness and color separation circuits. 5. The filter circuit (22) according to claim 4, wherein the filter circuit (22) is a trap circuit (22a) for attenuating components other than the required frequency components of the 4.43 MHz band, which is the color part carrier and signal frequency of the PAL signal, and the color part carrier signal frequency of the PAL signal. 2. A luminance and color separation circuit capable of processing two broadcast methods, which is composed of a 4.43 MHz band pass filter (BPF2) that passes a signal component of 4.43 MHz and a signal component of 4.43 MHz.