KR960003744Y1 - Sub-screen signal level auto compensating apparatus - Google Patents

Abstract

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Description

Self-leveling device for two-screen TV

1 is a block diagram showing a conventional two-screen television.

2 is a block diagram showing an automatic screen level compensating device for a two screen television according to the present invention;

FIG. 3 is an exemplary view of the sub picture level adjustment circuit shown in FIG.

4 is another exemplary embodiment of the sub picture level adjustment circuit shown in FIG.

5 is a schematic diagram of the PIP processing circuit shown in FIG.

6 is a detailed circuit diagram of the luminance level adjusting unit shown in FIG.

7 is an input waveform diagram for explaining the operation of the sub picture level adjustment circuit according to the present invention.

* Explanation of symbols for main parts of the drawings

10: first RF detection circuit 20: first luminance and color signal separation circuit

30: second RF detection circuit 40: second luminance and color signal separation circuit

50: video signal switching circuit 60: sub picture level adjustment circuit

70: PIP processing circuit 80: luminance and color signal demodulation circuit

90: the award hall

The present invention relates to an automatic screen level compensator for two screen televisions. More specifically, the level of the parent screen and the sub screen is large so as to minimize the brightness variation of the child screen according to the brightness of the parent screen. In this case, the present invention relates to an automatic screen level compensator for displaying an optimal screen by compensating the screen level to increase or decrease to prevent the screen from becoming too dark or excessively bright.

Conventionally used two-screen televisions are constructed as shown in FIG.

The two-screen TV shown in the drawing shows first and second RF detection circuits (1) and (3) for detecting and outputting a video signal and an audio signal independently of the signals selected independently through the first and second antennas, respectively, and the first screen. And outputting the image signal outputted from the 2RF detection circuit (1) (3) into a luminance signal (Y) and a color signal (C), and outputting the first, second luminance and color signal separation circuits (2) and (4). The brightness and color signals output from the 1, 2 luminance and color signal separation circuits 2 and 4 are switched according to the selected mode, and separated into a parent video signal and a self image signal, and then the PIP processing circuit 60 and the brightness and It consists of a video signal switching circuit 50 which passes through the color signal demodulation circuit 7 and supplies it to the water pipe 8.

In the conventional two-screen television configured as described above, the beam current of the water pipe rises more than specified, and the R.G. When the AC level supplied to B decreases, the parent screen is very bright and the child screen is dark, and the parent screen is optimal because it is limited at the prescribed level, but the child screen is too dark. If the peripheral circuit is not operated at all, there is a problem that the magnetic screen is too bright, and the beam current rises over the specified RG When the DC level supplied to B decreases, the parent screen is optimal because it is limited at the specified level, but the screen is too dark. On the contrary, when the full screen is very dark and the screen is brightest, the peripheral circuit does not operate at all. There was a problem that the screen is too bright.

Accordingly, an object of the present invention is to provide a self-screening level compensator for a two-screen television that compensates for the brightness signal level of a child screen according to the brightness level of the parent screen to minimize the change of brightness of the child screen according to the brightness of the parent screen. have.

In order to achieve the above object, the present invention receives the luminance signals and the color signals of different broadcast signals respectively received by two antennas and passed through the first and second RF detection circuits and the first and second luminance and color signal separation circuits. A video signal switching circuit for separating and outputting the parent video signal and the child video signal, and outputting the sub picture level adjustment voltage according to the level difference between the brightness signal of the parent screen and the brightness signal of the child screen outputted from the video signal switching circuit. Demodulating the parent / child composite luminance and color signals outputted from the PIP processing circuit, a PIP processing circuit for adjusting the brightness level of the magnetic screen according to the voltage output from the sub picture level adjusting circuit, Characterized in that it consists of a luminance and color signal demodulation circuit to be supplied to the water tube.

Hereinafter, the present invention will be described in more detail with reference to the illustrated drawings.

FIG. 2 is a block diagram showing a self-screening level compensator for a dual-screen (PIP) television according to the present invention, wherein the first and second RF detection circuits 10 and 30 are independently connected to each other through the first and second antennas. The tuned signal is detected to be a video signal and an audio signal, and the modal signal is supplied to the first, second luminance and color signal separation circuits 20 and 40 which separately output the luminance signal and the color signal.

The video signal switching circuit 50 switches the luminance and color signals outputted from the first, second luminance and color signal separation circuits 30 and 40 to separate the parent video signal and the self image signal, and the PIP processing circuit 70 to be described later. And through the luminance and color signal recovery circuit (80), are supplied to the water pipe (90).

The magnetic screen level adjusting circuit 60 is configured to output the magnetic screen level adjusting voltage according to the level difference between the full screen luminance signal and the magnetic screen luminance signal outputted from the video signal switching circuit 50. Examples are shown in FIGS. 3 and 4.

The sub picture level adjusting circuit 60 shown in FIG. 3 is configured to multiply the parent signal brightness signal output from the image signal switching circuit 50 and the sub picture brightness signal level difference by a predetermined gain and output the multiplicity of the brightness signals. Transistors Q1 and Q2 that are differentially amplified by a level, a plurality of bias resistors, and transistors Q3 and vias resistance and the transistor that supply constant current to the emitter terminals of the transistors Q1 and Q2. A differential amplifier 62 composed of a blocking transformer L1 having a balanced output of (Q1) and (Q2) as a soft balance output and a noise component included in the adjustment voltage output from the differential amplifier 62 are removed. It consists of a low pass filter composed of a resistor R8 and a condenser C2, and a low pass filter portion 64 composed of a plurality of resistors R12 and R13 for setting reference voltages of the magnetic field level adjustment voltage.

In addition, the differential amplifier 62 of the sub picture level adjusting circuit 60 shown in FIG. 4 receives an op amp and a resistor for differentially amplifying the sub picture signal and the sub picture luminance signal as inputs, respectively. It consists of (R1-R4).

Meanwhile, as shown in FIG. 5, the PIP processing circuit 70 includes a demodulator 71 for demodulating the luminance signal and the color signal for the sub picture output from the video signal switching circuit 50, and the demodulator 71. A controller that converts the color difference signal RY (BY) output from the digital signal into a digital signal, stores it in the memory unit 73, reads it faster than the normal speed, compresses the color difference signal to a certain size, and converts and outputs the analog signal. (72), a modulator (74) for modulating the color difference signal compressed and output from the controller (72) into a color signal and a luminance signal, and the level of the luminance signal output from the modulator (74) is adjusted to a sub picture level. The luminance level adjusting unit 75 adjusted according to the voltage output from the circuit 60, and the luminance and color signals of the sub-screen whose luminance level is adjusted by the luminance level adjusting unit 75 are mixed with the luminance and color signals for the parent screen. Outputs the luminance signal and the parent-purple signal Consists west 76, the luminance level adjusting unit 75 has the embodiment as illustrated in Figure 6.

The luminance level adjusting unit 75 shown in FIG. 6 is applied to the voltage output from the transistor Q25 and the bias unit operating according to the luminance signal Y level output from the modulator 74 of the PIP processing circuit 70. Transistors Q26 and Q24 that determine the screen luminance signal level according to the voltage output from the transistor Q26 and the screen level adjustment circuit 60 whose operation points are determined, and the screen level adjustment circuit ( Transistor Q21 for controlling the emitter current of transistor Q22 according to the voltage output from 60 and collector current are determined according to the operation of transistor Q21 to control the emitter current of transistor Q24. It consists of (Q23).

The operation process of the sub picture level automatic compensation device of the present invention having the configuration as described above is as follows.

The broadcast signal of the parent / child screen respectively received from the first and second antennas of the two-screen (PIP) reproducing television employing the sub picture level automatic compensation device shown in FIG. 2 is provided with the first and second RF detection circuits 10 ( 30), the video signal and the audio signal are separated, and the audio signal of the parent / child screen is supplied to the audio signal processing circuit through the video signal switching circuit 50, which will be described later. 2 are supplied to the luminance and color signal separation circuits 20 and 40, and are separated into luminance and color signals, respectively, and are supplied to the image signal switching circuit 50.

The video signal switching circuit 50 switches the luminance signal and the color signal respectively output from the first, second luminance and color signal separation circuits 20 and 40 according to the selected mode to display the parent image signal (Y + C) and the self image. The signal is separated into the signal Y + C and then supplied to the PIP processing circuit and the parent / child luminance signal Y is supplied to the sub picture level adjustment circuit 60 shown in FIGS. 3 and 4. .

In this manner, the parent screen luminance signal Y and the sub screen luminance signal Y outputted from the video signal switching circuit 50 have waveforms such as (a) and (b) shown in FIG. When supplied to the base terminal and the operational amplifier OP of the transistors Q1 and Q2, which are the differential amplifiers of the differential amplifier 62 shown in FIG. 4 and FIG. 4, respectively, the luminance signal Y for the parent screen and the magnetic screen are used. A waveform such as (c) of FIG. 7 multiplied by a gain multiplied by a difference of the luminance signal Y is output and supplied to the low pass filter unit 64. The signal output from the differential amplifier is low pass through the blocking transformer L. It is supplied to the filter part 64.

As shown in (c) of FIG. 7 supplied to the low pass filter unit 64, the noise level is removed through the low pass filter formed by the resistor R8 and the capacitor C2, and then the resistors R12 and R13. Is added to the reference voltage of the sub picture level adjustment voltage, which is determined by?, And is supplied to the sub picture brightness level adjusting unit 75 of the PIP processing circuit 70.

On the other hand, the luminance signal and the color signal of the sub picture output from the image signal switching circuit 50 are demodulated by the demodulator 71 and then converted into a digital signal by an analog-to-digital converter internally provided to the controller 72 to be converted into a digital signal. 73. In this case, the controller 72 reads and compresses the data stored in the memory unit 73 at a speed faster than the speed of storing the digital data in the memory unit 73, and then stores the digital-to-analog converter. The analog signal is converted into an analog signal and supplied to the modulator 74.

The luminance signal for the magnetic screen modulated by the modulator 74 is supplied to the luminance level adjusting unit 75 and the level is varied according to the voltage output from the magnetic screen level adjusting circuit 60. The luminance level adjusting unit ( The luminance signal for the magnetic field supplied to the 75 is supplied to the base terminal of the transistor Q25 shown in FIG. 6, and the level is varied in accordance with the voltage output from the magnetic field level adjusting circuit 60 so that the transistor Q22 ( Output from Q24).

That is, the current flowing through the collectors of the transistors Q21 to Q26 of the luminance level adjusting unit 75 shown in FIG. 6 is equal to IQ25 = IQ26 = IQ21 + IQ22 = IQ23 + IQ24.

Therefore, when the sub picture level adjusting voltage output from the sub picture level adjusting circuit 60 increases, the IQ 21 and I Q 24 become large and the I Q 25 and I Q 26 are constant, so that the levels of the sub luminance signal for the sub picture are amplified and output. When the sub picture level adjustment voltage decreases, the opposite operation is performed so that the sub-level luminance signal becomes low.

As such, the level of the luminance signal is varied according to the magnetic screen level adjustment voltage output from the magnetic screen level adjusting circuit 60, passes through the mixer 76, and passes through the luminance and color signal demodulation circuit 80 to receive the water pipe 90. ), So the sub-display is optimally displayed.

The operation and effect of the present invention, which operates as described above, adjusts the level of the luminance signal for the child screen according to the level difference between the luminance signal for the parent screen and the luminance signal for the child screen. By increasing or decreasing the screen level, the optimal subscreen can be provided by preventing the subscreen from being excessively dark or excessively bright.

Claims (7)

Input the luminance signal and the color signal of the different broadcast signals respectively received from the two antennas and passed through the first and second RF detection circuits and the first, second luminance and color signal separation circuits, respectively, to separate the parent video signal and the self video signal. An image signal switching circuit to be output, a child screen level adjusting circuit for outputting a child screen bell control voltage according to a level difference between the brightness signal of the parent screen and the brightness signal of the child screen output from the video signal switching circuit, and the magnetic screen A PIP processing circuit for adjusting the brightness level of the magnetic screen according to the voltage output from the level adjusting circuit, and a luminance and color signal demodulation circuit for demodulating the parent / child composite luminance and color signals outputted from the PIP processing circuit and supplying them to the receiving tube. Self-winding television automatic compensation device of the two-screen television, characterized in that consisting of. 2. The display device as claimed in claim 1, wherein the sub picture level adjusting circuit comprises: an automatic amplifier for multiplying and outputting a constant gain multiplied by a level difference between the sub picture brightness signal and the sub picture brightness signal output from the video signal switching circuit; A self-leveling level compensator for two-screen television, characterized by comprising a low pass filter that removes a noise component included in an output adjustment voltage. The blocking circuit of claim 2, wherein the differential amplifier comprises first and second transistors differentially amplified by the levels of the parent screen luminance signal and the subscreen luminance signal, and a balanced output of the first and second transistors as an unbalanced output. A self-screening television auto-compensation device for a two-screen television comprising a trance. The apparatus of claim 2, wherein the differential amplifier comprises a differential image amplifier that amplifies the luminance signal for the parent screen and the luminance signal for the sub picture as an input. 3. The self-leveling level compensator for two screens of claim 2, wherein the low pass filter comprises a low pass filter comprising a resistor and a condenser to remove noise components included in the luminance adjustment voltage output from the differential amplifier. . 2. The PIP processing circuit of claim 1, wherein the PIP processing circuit demodulates a luminance signal for a sub picture and a color signal output from a video signal switching circuit, and converts the color difference signal output from the demodulation unit into a digital signal and stores the digital signal. And a controller for compressing the color difference signal to a predetermined size by reading at a speed higher than a storage speed and outputting an analog conversion, and a modulator for modulating the color difference signal compressed and output from the controller into a color signal and a luminance signal, and the modulator. A brightness level adjusting unit for adjusting the level of the luminance signal outputted from the sub-screen according to the voltage output from the sub-screen level adjusting circuit, and the luminance and color signals of the sub-screen whose brightness level is adjusted by the brightness level adjusting unit to the brightness and color signals for the parent screen. It is composed of a mixer unit for mixing and outputting the parent-child luminance signal and the parent-purple signal. Automatic TV Compensation Device 7. The display device of claim 6, wherein the luminance level adjusting unit comprises a fifth transistor operating according to the luminance signal level output from the modulator of the PIP processing circuit, and a sixth transistor and a sub picture level whose operating point is determined according to a voltage output from the bias unit. Second and fourth transistors for determining and outputting a sub picture luminance signal level according to a voltage output from an adjustment circuit and a first transistor for controlling the emitter current of the second transistor according to a voltage output from the sub picture level adjustment circuit. And a third transistor configured to control a emitter current of the fourth transistor by determining a collector current according to the operation of the first transistor.