KR920005454Y1 - Brightness delayed time selecting circuit by transmition type of color television - Google Patents

Abstract

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Description

Luminance delay time selection circuit according to the transmission method of color TV

1 is a conventional circuit diagram.

2 is a circuit diagram of the present invention.

* Explanation of symbols for main parts of the drawings

100: chroma trap circuit 200: chroma filter circuit

300: luminance signal delay circuit 310: arm type luminance delay circuit

320: Secam method luminance delay circuit 400: chroma decoder circuit

500: chroma matrix circuit 600: luminance delay time switching circuit

TR ₁ , TR ₂ : switching transistor C ₁ , C ₂ : coupling capacitor

R ₁ to R ₅ : voltage drop resistance R ₆ : load resistance

The present invention relates to a Y-Delay Time selection circuit that can be used for PAL / SECAM color TVs. In particular, the delay time of the luminance signal is increased depending on the transmission method (PAL, SECAM). The present invention relates to a luminance delay time selection circuit according to a transmission method of a color TV that removes an inconsistency between luminance and color signals generated by different transmission methods to improve a screen state.

Conventionally, when receiving a transmitted TV signal and displaying an image on a screen, as illustrated in FIG. 1, the chroma trap circuit 100, the chroma filter circuit 200, the luminance signal delay circuit 300, A circuit consisting of a chroma decoder circuit 400 and a chroma matrix circuit 500 is used. When a color video blanking signal transmitted to the circuit is applied, luminance from the video synthesis signal is applied. After separating the signal and the chroma signal, the luminance signal is delayed for a predetermined time using a delay line, and the chroma signal is demodulated, and then the synthesized delay signal and the demodulated chroma signal are recombined and applied to the CRT. You can watch the screen.

At this time, since the signal of the arm alteration by line or sequence de couleurs avec ME'moire method is different from each other, the delay time of the separated luminance signal must also be different from each other. Regardless of the delay, the delay time of the luminance signal does not match when the transmission method is changed. Therefore, the luminance signal and the chroma signal are shifted on the screen. TV screen viewing was difficult because of the same poor screen condition.

In order to solve the above drawbacks, the present invention divides the luminance signal delay circuit into a delay time suitable for each transmission method, but uses a luminance delay time switching circuit to automatically delay the luminance signal according to the transmission method. When the signal is synthesized, the luminance signal and the chroma signal coincide with each other so that a clean screen can be always viewed regardless of the transmission method. Hereinafter, the present invention will be described with reference to the accompanying drawings.

As shown in FIG. 2, the chromatographic circuit 100 that separates the luminance signal from the received image synthesis signal 10, and the chroma filter circuit 200 that separates only the chroma signal from the received image synthesis signal And an arm method luminance delay circuit 310 for delaying the luminance signal by a delay time suitable for the arm method, a Secam method luminance delay circuit 320 for delaying the luminance signal for the Secam method, and the separated chroma signal. In a color TV including a demodulated chroma decoder circuit 400, the video composite signal input terminal 10 is connected to the chroma trap circuit 100 and the chroma filter circuit 200, respectively, and the chroma trap circuit 100 ) Is an arm type luminance delay circuit 310 for delaying the separated luminance signal by a delay time suitable for an arm type, and a Secam method luminance delay circuit 320 for delaying the separated luminance signal to fit a Secam method. Respectively, and the chroma filter circuit 200 is connected to the chroma decoder circuit 400, and the output terminal A of the arm and seqham luminance delay circuits 310 and 320 and the chroma deco circuit 400 are connected to each other. ) And (B) are switched in accordance with the output of the chroma decoder circuit 400 and connected to the luminance delay time switching circuit 600 for selectively applying the outputs of the arms and the Seqham luminance delay circuits 310 and 320. It is configured by.

20 denotes a luminance signal output terminal.

The luminance delay time switching circuit 600 is connected to the coupling capacitor (C ₁ ) (C ₂ ) and the resistance to drop (R _{1 ~} R ₄ ) to the base terminal of the switching transistor (TR ₁ ) (TR ₂ ) , of the switching transistor (TR _1), the collector terminal of the (TR ₂₎ is connects to the B ⁺ terminal through a load resistor (R _6), the transistor for the switch _{(TR 1), (TR 2} ) for the emitter terminal It is grounded through the voltage drop resistor R _{5 and} connected to the luminance signal output terminal 20.

Referring to the effect of the present invention configured as described above in detail.

The image synthesis signal applied through the image synthesis signal input terminal 10 is separated into a luminance signal and a chroma signal by the known chroma trap circuit 100 and the known chroma filter circuit 200, respectively, and the chroma trap circuit 100 The luminance signal outputted from the Rx is applied to the arm type luminance delay circuit 310 and the Secam type luminance delay circuit 320 having different delay times, respectively. The arm type luminance delay circuit 310 is set to fit the arm type. The delayed luminance signal is delayed by using a delay line, and the Seqham luminance delay circuit 320 delays and outputs the input luminance signal to conform to the Secam method.

The arm and seqham luminance delay circuits 310 and 320 are circuits for delaying and then outputting the input signals differently in time, and a technique for delaying the signals in time may use various types of delay circuits known in the art. Can be.

In addition, the chroma decoder circuit 400 demodulates the chroma signal output from the chroma filter circuit 200. In this case, a luminance delay time to be described later is output by outputting a different driving signal according to a transmission method through output terminals A and B. FIG. The switching circuit 600 is controlled to selectively apply the outputs of the arms and the Secam luminance delay circuits 310 and 320.

First, when the signal transmission method is an arm method, a low signal is output from the output terminal (a) of the chroma decoder circuit 400 and a high signal is output from another output terminal (B), respectively. When the decoder circuit 400 is the SECAM method, the output terminal A is H and the output terminal B is L, and in the PAL method, the output terminal A is L and the output terminal B is H. The chroma decoder circuit ( Since the high signal output to the output terminal B of the 400 is applied to the base terminal of the transistor TR ₁ via the voltage drop resistor R ₁ (R ₃ ) in the luminance delay time switching circuit 600, the transistor (TR ¹ ) is conducted.

In this case, since a luminance signal delayed to match the arm method output from the arm type luminance delay circuit 310 is applied to the base terminal of the transistor TR ₁ through the coupling capacitor C ₁ , the luminance signal is transmitted to the transistor TR. ¹ ) is output to the circuit signal output terminal 20 by the DC voltage applied through the circuit, and another transistor TR ₂ is cut off by a humanized low signal from the output terminal A of the chroma decoder circuit 400. In this state, the luminance signal outputted from the Seqam luminance delay circuit 320 is not output.

Therefore, when receiving an arm type signal, a luminance signal delayed for the arm type can be obtained.

On the other hand, when the signal transmission method is a SECAM method, a high signal is output from the output terminal A of the chroma decoder circuit 400 and a low signal is output from another output terminal B. As a result, the transistor TR ₁ is in a non-conducting state, and the high signal output to the output terminal A of the chroma decoder circuit 400 passes through the voltage drop resistor R ₂ (R ₄ ) to pass through the transistor TR. since ₂₎ is applied to the base terminal of the transistor (TR ₂₎ it is conductive.

Therefore, since the luminance signal delayed in accordance with the Secam method outputted from the Secam method luminance delay circuit 320 is output to the luminance signal output terminal 20 by the DC voltage applied through the conducting transistor TR ₂ . Likewise, when receiving a Secam method, a luminance signal delayed in accordance with the Secam method can be obtained.

As described above, the present invention automatically changes the delay time of the luminance signal whenever the transmission method of the signal is changed, so that the user can watch a clear screen in which the luminance signal and the chroma signal match in any broadcasting method such as the arm or secam method. It is effective.

Claims (1)

The chromatographic circuit 100 and the chroma filter circuit 200 are connected to the image synthesis signal input terminal 10, respectively, and the chroma trap circuit 100 delays the separated luminance signal by a delay time corresponding to the arm method. And an arm type luminance delay circuit 310 and a secam method luminance delay circuit 320 for delaying the separated luminance signal to match the Secam method. The chroma filter circuit 200 may be configured as the chroma decoder circuit. In the known connection connected to 400, the chroma is output to the output terminals A and B of the arm type luminance delay circuit 30, the Secam method luminance delay circuit 320, and the chroma decoder circuit 400. According to the signal output from the decoder circuit, the luminance delay time switching circuit 600 for selectively applying the outputs of the arm method and the Secam method luminance delay circuits 310 and 320 is connected to always display a clean screen regardless of the broadcasting method. Phrase to watch A luminance delay time selection circuit according to the transmission method of a color TV, characterized in that.