JPH04284094A - Multi-screen television - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-screen television that displays two or more video signals on one display device.

0002

2. Description of the Related Art In recent years, there has been an increasing demand for multi-screen televisions that display a plurality of images on the same screen, such as picture-in-picture that displays a child screen within a main screen.

An example of the above-mentioned conventional multi-screen television will be described below with reference to the drawings. FIG. 3 shows a circuit block diagram of a conventional multi-screen television. In FIG. 3, reference numeral 1 denotes a video signal A input terminal, which is connected to a YC separation circuit 2 and a synchronization circuit 3. One output terminal of the YC separation circuit 2 is connected to the display size creation circuit 5, and the other output terminal is connected to the display size creation circuit 6 via the color demodulation circuit 4.
connected to. Reference numeral 7 denotes a video signal B input terminal, which is connected to a YC separation circuit 8 and a synchronization circuit 9. One output terminal of the YC separation circuit 8 is connected to a display size generation circuit 11, and the other output terminal is connected to a display size generation circuit 12 via a color demodulation circuit 10.

Reference numeral 13 denotes a switching means, which is a display size creation circuit 5.
and the output signal of the display size creation circuit 11 are switched and output to the luminance signal output terminal 14. Reference numeral 15 denotes a switching means, which switches the output signal of the display size creation circuit 6 and the output signal of the display size creation circuit 12 and outputs it to the color difference signal output terminal 16.

The output terminal of the synchronous circuit 3 is connected to the synchronous signal A output terminal 17, and the output terminal of the synchronous circuit 9 is connected to the synchronous signal B output terminal.
It is connected to the output terminal 18. The operation of the multi-screen television configured in this manner will be described below. First, the video signal A input from the video signal A input terminal 1 is separated into a luminance signal and a carrier color signal by the YC separation circuit 2.
The luminance signal is input to the display size generation circuit 5, and the carrier color signal is input to the color demodulation circuit 4, where it is converted into color difference signals (U=R-Y and V=B-Y).
) and then input to the display size creation circuit 6.

Display size creation circuits 5 and 6 enlarge or reduce the luminance signal output from the YC separation circuit 2 and the color difference signal output from the color demodulation circuit 4 to a desired display size of the video signal A, respectively.

On the other hand, the video signal B input from the video signal B input terminal 7 is separated into a luminance signal and a carrier color signal by a YC separation circuit 8, and the luminance signal is input to a display size creation circuit 11, which converts it into a carrier color signal. is a color difference signal (U=
After being demodulated into RY and V=BY), it is input to the display size creation circuit 12.

In the display size creation circuits 11 and 12, YC
The luminance signal output from the separation circuit 8 and the color difference signal output from the color demodulation circuit 10 are each enlarged or reduced to a desired size for displaying the video signal B.

In the switching means 13, the display size creation circuit 5
and the output signal of the display size creation circuit 11 are switched, and the luminance signals of two screens, video signal A and video signal B, are output to the luminance signal output terminal 14. Furthermore, the switching means 15 switches the output signal of the display size creation circuit 6 and the output signal of the display size creation circuit 12, and outputs the color difference signals of two screens, video signal A and video signal B, to the color difference signal output terminal 16. Ru.

The synchronization circuit 3 extracts the synchronization signal of the video signal A and outputs it to the synchronization signal A output terminal 17, and the synchronization circuit 9 extracts the synchronization signal of the video signal B and outputs it to the synchronization signal A output terminal 17. It is output to the output terminal 18. The signals from the luminance signal output terminal 14 and the color difference signal output terminal 16 are displayed in synchronization with the signal from the synchronization signal A output terminal.

[0011]

However, in the above configuration, the potentials of the color difference signal of the video signal A, which is the output of the color demodulation circuit 4, and the color difference signal of the video signal B, which is the output of the color demodulation circuit 10, are If the potentials of the color difference signals of the video signal A are different, and the colors are reproduced based on the potential of the color difference signal of the video signal A, there is a problem in that the hue of the video signal B is displayed differently from the original hue.

[0012] Furthermore, when the potentials of video signal A and video signal B are different, if the brightness is reproduced based on the potential of video signal A, the brightness of video signal B will be displayed different from the original brightness. had.

In view of the above-mentioned problems, the present invention aims to provide a multi-screen television that correctly reproduces the colors of video signals A and B even when the potentials of the color difference signals of video signals A and B are different. This is the purpose.

[0014] Furthermore, the present invention provides video signal A and video signal B.
It is an object of the present invention to provide a multi-screen television that can correctly reproduce the brightness of a video signal A and a video signal B even when the potentials of the video signals A and B are different.

[0015]

[Means for Solving the Problems] In order to solve the above problems, the multi-screen television of the present invention includes a first color demodulation circuit for extracting a color difference signal of a first video signal, and a synchronization circuit for synchronizing the first video signal. A first synchronous circuit that extracts the signal, a first potential detection circuit that detects the potential of the color difference signal from each output signal of the first color demodulation circuit and the first synchronous circuit, and a color difference signal of the second video signal. a second color demodulation circuit that extracts the synchronization signal of the second video signal, a second synchronization circuit that extracts the synchronization signal of the second video signal, and detects the potential of the color difference signal from each output signal of the second color demodulation circuit and the second synchronization circuit. a second potential detection circuit that calculates the difference between the output signals of the first potential detection circuit and the second potential detection circuit; a subtracter that adds the output signals of the second color demodulation circuit and the subtracter; It is equipped with an adder.

Further, the multi-screen television of the present invention includes a first YC separation circuit for extracting the luminance signal of the first video signal, a first synchronization circuit for extracting the synchronization signal of the first video signal, and a first YC separation circuit for extracting the luminance signal of the first video signal. a first potential detection circuit that detects the potential of the first video signal from each output signal of the first YC separation circuit and the first synchronization circuit; and a second YC separation circuit that extracts the luminance signal of the second video signal.
a C separation circuit, a second synchronization circuit that extracts a synchronization signal of the second video signal, and a second synchronization circuit that detects the potential of the second video signal from each output signal of the second YC separation circuit and the second synchronization circuit. 2
a potential detection circuit, a subtracter that takes the difference between each output signal of the first potential detection circuit and the second potential detection circuit, and an adder that adds each output signal of the second YC separation circuit and the subtracter. It has been established.

[0017]

[Operation] With the above-described configuration, even if the potentials of the color difference signals after color demodulation of the first video signal and the second video signal are different, the potential difference between the two is detected and the difference is converted into the second color signal. By adding and correcting the output signal of the demodulation circuit,
Even when color reproduction is performed based on the potential of the color difference signal of the first video signal, the hue of the second video signal can be correctly reproduced.

Furthermore, with the above-described configuration, the present invention detects the potential difference between the first video signal and the second video signal even when the potentials are different, and uses the difference as the output signal of the second YC separation circuit. By adding and correcting the potential of the first video signal, even when reproducing the brightness based on the potential of the first video signal, the potential of the second video signal is
The brightness of the video signal can be reproduced correctly.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit block diagram of a multi-screen television according to a first embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a video signal A input terminal, which is connected to a YC separation circuit 2 and a synchronization circuit 3. One output terminal of the YC separation circuit 2 is connected to the display size creation circuit 5, and the other output terminal is connected to the color demodulation circuit 4. The output terminal of the color demodulation circuit 4 is connected to the display size creation circuit 6 and the potential detection circuit 19, and the output terminal of the synchronization circuit 3 is connected to the potential detection circuit 19 and the synchronization signal A output terminal 17.

Reference numeral 7 denotes a video signal B input terminal, which is connected to a YC separation circuit 8 and a synchronization circuit 9. One output terminal of the YC separation circuit 8 is connected to a display size creation circuit 11, and the other output terminal is connected to a color demodulation circuit 10. The output terminal of the color demodulation circuit 10 is connected to the adder 22 and the potential detection circuit 20, and the output terminal of the synchronization circuit 9 is connected to the potential detection circuit 20 and the synchronization signal B output terminal 18.

21 is a subtracter that takes the difference between the output signals of the potential detection circuits 19 and 20. The output signal of the subtracter 21 is added to the output signal of the color demodulation circuit 10 in an adder 22, and the output signal of the adder 22 is The terminal is connected to the display size creation circuit 12.

The switching means 13 switches the output signals of the display size creation circuit 5 and the display size creation circuit 11 and outputs them to the luminance signal output terminal 14, and the switching means 15 switches between the display size creation circuit 6 and the display size creation circuit 12. The respective output signals are switched and output to the color difference signal output terminal 16.

The operation of the multi-screen television configured as described above will be explained below. First, video signal A
The video signal A input from the input terminal 1 is separated into a luminance signal and a carrier color signal by a YC separation circuit 2, the luminance signal is inputted to a display size creation circuit 5, and the carrier color signal is converted to a color difference signal by a color demodulation circuit 4. After being demodulated into (U=RY and V=BY), it is input to the display size creation circuit 6.

On the other hand, the video signal B inputted from the video signal B input terminal 7 is separated into a luminance signal and a carrier color signal by a YC separation circuit 8, and the luminance signal is inputted to a display size creation circuit 11, which converts it into a carrier color signal. is input to the color demodulation circuit 10 and demodulated into color difference signals (U=RY and V=BY).

In the potential detection circuit 19, the position of the pedestal of the color difference signal output from the color demodulation circuit 4 is detected from the output signal of the synchronization circuit 3, and the 0 level of the color difference signal of the video signal A is output. Further, in the potential detection circuit 20, the position of the pedestal of the color difference signal output from the color demodulation circuit 10 is detected from the output signal of the synchronization circuit 9, and the 0 level of the color difference signal of the video signal B is outputted.

The subtracter 21 detects the difference in 0 level between the color difference signals of the video signal A and the video signal B by taking the difference between the output signals of the potential detection circuit 19 and the potential detection circuit 20. In the adder 22, the output signal of the subtracter 21 is added to the output signal of the color demodulation circuit 10, and the result is input to the display size creation circuit 12, where the difference in 0 level between the color difference signals of the video signal A and the video signal B is corrected. Ru. Color reproduction is performed based on the 0 level of the color difference signal of the video signal A, but by this correction, the hue of the video signal B is also correctly reproduced.

In the display size creation circuits 5 and 6, the luminance signal output from the YC separation circuit 2 and the color difference signal output from the color demodulation circuit 4 are expanded and expanded to the desired display size of the video signal A.
In the display size creation circuits 11 and 12, the luminance signal output from the YC separation circuit 8 and the color difference signal output from the color demodulation circuit 10 are respectively enlarged or reduced to the desired display size of the video signal B.

In the switching means 13, the display size creation circuit 5
The output signals of the display size creation circuit 11 are switched, and the luminance signals of the two screens of video signals A and B are outputted to the luminance signal output terminal 14. Further, the switching means 15 switches the output signals of the display size generation circuit 11 and the display size generation circuit 12, and outputs color difference signals of two screens of video signals A and B to the color difference signal output terminal 16.

The synchronization signal of the video signal A, which is the output of the synchronization circuit 3, is output from the synchronization signal A output terminal 17, and the synchronization signal of the video signal B, which is the output of the synchronization circuit 9, is output from the synchronization signal B output terminal 17. However, the signals from the luminance signal output terminal 14 and the color difference signal output terminal 16 are displayed in synchronization with the synchronization signal of the video signal A.

As described above, according to this embodiment, the potential detection circuits 19 and 20 detect the 0 level of each color difference signal of the video signal A and the video signal B, and the output signals of the potential detection circuits 19 and 20. By providing a subtracter 21 that takes the difference and an adder 22 that adds the output signal of the subtracter 21 to the output signal of the color demodulation circuit 10, even if the 0 levels of the color difference signals of the video signal A and the video signal B are different, , the difference in the 0 level between the two is detected, and the difference is added to the output signal of the color demodulation circuit 10 and corrected, so that even if the color reproduction is based on the 0 level of the color difference signal of the video signal A, The hue of signal B can be reproduced correctly.

FIG. 2 is a circuit block diagram of a multi-screen television according to a second embodiment of the present invention. In FIG. 2, reference numeral 1 denotes a video signal A input terminal, which is connected to a YC separation circuit 2 and a synchronization circuit 3. One output terminal of the YC separation circuit 2 is connected to the display size creation circuit 5 and the potential detection circuit 23, and the other output terminal is connected to the color demodulation circuit 4. The output terminal of the color demodulation circuit 4 is connected to the display size creation circuit 6, and the output terminal of the synchronization circuit 3 is connected to the potential detection circuit 23 and the synchronization signal A output terminal 17.

Reference numeral 7 denotes a video signal B input terminal, which is connected to a YC separation circuit 8 and a synchronization circuit 9. One output terminal of the YC separation circuit 8 is connected to the potential detection circuit 24 and the adder 26,
The other output terminal is connected to the color demodulation circuit 10. The output terminal of the color demodulation circuit 10 is connected to the display size creation circuit 12, and the output terminal of the synchronization circuit 9 is connected to the potential detection circuit 24 and the synchronization signal B output terminal 18.

A subtracter 25 takes the difference between the output signals of the potential detection circuits 23 and 24, and the output signal of the subtracter 25 is added to the output signal of the YC separation circuit 8 in an adder 26.
The output terminal 6 is connected to the display size creation circuit 11.

The switching means 13 switches the output signals of the display size creation circuit 5 and the display size creation circuit 11 and outputs them to the luminance signal output terminal 14, and the switching means 15 switches between the display size creation circuit 6 and the display size creation circuit 12. The respective output signals are switched and output to the color difference signal output terminal 16.

The operation of the multi-screen television configured as described above will be explained below. First, video signal A
Video signal A input from input terminal 1 is sent to YC separation circuit 2
The luminance signal is input to the display size creation circuit 5, and the carrier color signal is input to the color demodulation circuit 4.
The signals are demodulated into color difference signals (U=RY and V=BY) and then input to the display size creation circuit 6.

On the other hand, the video signal B input from the video signal B input terminal 7 is separated into a luminance signal and a carrier color signal by a YC separation circuit 8, and the luminance signal is sent to a potential detection circuit 24 and an adder 2.
6, and the carrier color signal is input to a color demodulation circuit 10 and demodulated into color difference signals (U=RY and V=BY).

The potential detection circuit 23 detects the pedestal position of the luminance signal output from the YC separation circuit 2 from the output signal of the synchronization circuit 3, and outputs the pedestal level of the video signal A. Further, the potential detection circuit 24 detects the pedestal position of the luminance signal output from the YC separation circuit 8 from the output signal of the synchronization circuit 9, and outputs the pedestal level of the video signal B.

The subtracter 25 detects the difference between the pedestal levels of the video signal A and the video signal B by taking the difference between the output signals of the potential detection circuit 23 and the potential detection circuit 24. In the adder 26, the output signal of the subtracter 25 is added to the output signal of the YC separation circuit 8, and the result is input to the display size creation circuit 11, and the difference in pedestal level between the video signal A and the video signal B is corrected. Although brightness reproduction is performed based on the pedestal level of video signal A, this correction also correctly reproduces the brightness of video signal B.

In the display size creation circuits 5 and 6, the luminance signal output from the YC separation circuit 2 and the color difference signal output from the color demodulation circuit 4 are respectively enlarged or reduced to the desired size for displaying the video signal A. In size creation circuits 11 and 12, YC
The luminance signal output from the separation circuit 8 and the color difference signal output from the color demodulation circuit 10 are each enlarged or reduced to a desired size for displaying the video signal B.

In the switching means 13, the display size creation circuit 5
The output signals of the display size creation circuit 11 are switched, and the luminance signals of the two screens of video signals A and B are outputted to the luminance signal output terminal 14. Furthermore, the switching means 15 switches the output signals of the display size creation circuit 6 and the display size creation circuit 12, and outputs the color difference signals of the two screens of video signals A and B to the color difference signal output terminal 16.

The synchronization signal of the video signal A, which is the output of the synchronization circuit 3, is output from the synchronization signal A output terminal 17, and the synchronization signal of the video signal B, which is the output of the synchronization circuit 9, is output from the output terminal 17 of the synchronization signal B. However, the signals from the luminance signal output terminal 14 and the color difference signal output terminal 16 are displayed in synchronization with the synchronization signal of the video signal A.

As described above, according to this embodiment, the potential detection circuits 23 and 24 detect the pedestal levels of the video signal A and the video signal B, and the difference between the output signals of the potential detection circuits 23 and 24 is calculated. By providing a subtracter 25 and an adder 26 that adds the output signal of the subtracter 25 to the output signal of the YC separation circuit 8, even if the pedestal levels of video signal A and video signal B are different, the pedestal levels of both can be adjusted. By detecting the difference and correcting the difference by adding it to the output signal of the YC separation circuit 8, even if the brightness is reproduced based on the pedestal level of the video signal A, the brightness of the video signal B can be correctly reproduced. Can be done.

[0044]

As described above, according to the present invention, the first color demodulation circuit extracts the color difference signal of the first video signal;
a first synchronization circuit that extracts a synchronization signal of the video signal; a first potential detection circuit that detects the potential of the color difference signal from each output signal of the first color demodulation circuit and the first synchronization circuit; a second color demodulation circuit for extracting a color difference signal of the video signal;
a second synchronous circuit that extracts the synchronous signal of the video signal; a second potential detection circuit that detects the potential of the color difference signal from each output signal of the second color demodulation circuit and the second synchronous circuit; By providing a subtracter that takes the difference between each output signal of the potential detection circuit and the second potential detection circuit, and an adder that adds each output signal of the second color demodulation circuit and the subtracter, the first Even if the potentials of the color difference signals after color demodulation of the video signal and the second video signal are different, the potential difference between the two is detected and the difference is added to the output signal of the second color demodulation circuit for correction. Even when color reproduction is performed based on the potential of the color difference signal of the first video signal, the hue of the second video signal can be correctly reproduced.

Furthermore, according to the present invention, the first YC separation circuit extracts the luminance signal of the first video signal, the first synchronization circuit extracts the synchronization signal of the first video signal, and the first YC separation circuit extracts the luminance signal of the first video signal. a first potential detection circuit that detects the potential of the first video signal from each output signal of the separation circuit and the first synchronization circuit;
a second YC separation circuit that takes out the luminance signal of the video signal; a second synchronization circuit that takes out the synchronization signal of the second video signal; each output of the second YC separation circuit and the second synchronization circuit; a second potential detection circuit that detects the potential of the second video signal from the signal; a subtracter that takes the difference between each output signal of the first potential detection circuit and the second potential detection circuit; and a second YC separation. By providing a circuit and an adder that adds each output signal of the subtracter, even if the potentials of the first video signal and the second video signal are different, the potential difference between the two is detected and the difference is added to the second video signal. Since it is corrected by adding it to the output signal of the YC separation circuit, even when the brightness is reproduced based on the potential of the first video signal, the brightness of the second video signal can be correctly reproduced.

[Brief explanation of the drawing]

FIG. 1 is a circuit block diagram of a multi-screen television in a first embodiment of the present invention.

FIG. 2 is a circuit block diagram of a multi-screen television in a second embodiment of the present invention.

FIG. 3 is a circuit block diagram of a conventional multi-screen television.

[Explanation of symbols]

1 Video signal A input terminal 7 Video signal B input terminal 2, 8 YC separation circuit 3, 9 Synchronization circuit 4, 10 Color demodulation circuit 5, 6, 11, 12 Display size creation circuit 13, 15
Switching means 14 Luminance signal output terminal 16 Color difference signal output terminal 17 Synchronous signal A output terminal 18 Synchronous signal B output terminal 19, 20, 23, 24 Potential detection circuit 21, 25
Subtractor 22, 26 Adder

Claims (2)

[Claims] 1. A first YC separation circuit that extracts a first video signal, a carrier color signal of the first video signal, and a first YC separation circuit that extracts a color difference signal from the carrier color signal of the first video signal. 1 color demodulation circuit, a first synchronization circuit that extracts a synchronization signal of the first video signal, and a first video signal obtained from each output signal of the first color demodulation circuit and the first synchronization circuit. a first potential detection circuit that detects the potential of the color difference signal;
a second YC separation circuit that extracts a carrier color signal of the second video signal; a second color demodulation circuit that extracts a color difference signal from the carrier color signal of the second video signal; A second synchronization circuit extracts a synchronization signal of the second video signal, and the potential of the color difference signal of the second video signal is determined from each output signal of the second color demodulation circuit and the second synchronization circuit. a second potential detection circuit to detect, a subtracter that takes the difference between each output signal of the first potential detection circuit and the second potential detection circuit, and each of the second color demodulation circuit and the subtracter. A multi-screen television equipped with an adder that adds output signals. 2. A first video signal, a first YC separation circuit for extracting a luminance signal of the first video signal, and a first synchronization circuit for extracting a synchronization signal of the first video signal. ,
a first potential detection circuit that detects the potential of the first video signal from each output signal of the first YC separation circuit and the first synchronization circuit; a second video signal; and a second video signal. a second YC separation circuit for extracting a luminance signal of the signal;
a second synchronization circuit that extracts a synchronization signal of the video signal; and a second potential that detects the potential of the second video signal from each output signal of the second YC separation circuit and the second synchronization circuit. a detection circuit, a subtracter that takes the difference between each output signal of the first potential detection circuit and the second potential detection circuit, and an addition that adds each output signal of the second YC separation circuit and the subtracter. A multi-screen television with equipment.