JPS6046689A - Signal superposing device - Google Patents

Abstract

PURPOSE:To prevent the generation of mutual interference by separating a color composite video signal of two systems into a Y signal and a chroma signal component, and mixing signals of the systems individually and then mixing both the mixed signals of both systems together. CONSTITUTION:The composite signal from a terminal 1 is applied by a Y-C separating circuit 7 and separated into the Y signal (c) and chroma signal (d), which are applied to a Y signal mixing circuit 7 and a chroma signal mixing circuit 9. An R, a G, and a B signal applied from a personal computer to terminals 4a-4c, on the other hand, are applied to a Y signal generating circuit 5 and a chroma signal generating circuit 6, and a Y signal (e) and a chroma signal (f) generated by those circuits are supplied to mixing circuits 8 and 9 respectively. Then, a Y-C mixing circuit 10 mixes the outputs of those mixing circuits 8 and 9 together to obtain a desired composite color video signal (i) of two systems, which is sent out from a terminal 1 to a following circuit.

Description

[Detailed Description of the Invention] Technical Field> The present invention is applicable to superimposing images of different systems, such as data from a burner computer, on a received image screen of television broadcasting, etc. The present invention relates to a signal superimposition device that is effective for.

<Background Art> Recently, personal computers have come to be used in ordinary homes. Attempts are now being made to connect a home color television receiver '1cRT display device to a personal computer and display data from the personal computer on the screen of the color television receiver. Furthermore, recently, color television broadcasting screens have been
A combination/system of a color television receiver and a personal computer that superimposes and displays data from a personal computer has been developed and is already commercially available.

<Disclosure of the Invention> The present invention provides a signal superimposition device suitable for use in such a combination system.

The signal superimposition device of the present invention separates a color composite video signal from a television receiver or the like into a luminance (Y) signal component and a chroma signal component, and separates each of these signals into a data system of a personal computer, etc. The two signals are individually added and mixed to generate one color composite video signal in which two systems of video information are superimposed.

<Example> The misfire 8A will be explained below according to the example shown in the drawings. FIG. 1 is a block diagram showing one embodiment of the device of the present invention, where 1 is a video input terminal, and 2 is the input terminal I.
A burst gate circuit 3 separates only the burst signal component from the color composite video signal supplied to the burst gate circuit 2;
．． A color subcarrier oscillation circuit that oscillates a 58 MHz color subcarrier signal; 4a, 4b, and 4c are R, G, and B input terminals, respectively; 5 is an R input terminal supplied to the input terminals 4a, 4b, and 4c;
G.

A Y signal generation circuit that generates a Y signal based on the B signal; 6 a chroma signal generation circuit that generates a chroma signal based on the R, G, and B signals and the color subcarrier signal from the color subcarrier oscillation circuit 3; , 7 is a y-c separation circuit that separates the color composite video signal supplied to the input terminal 1 into a Y signal and a chroma signal, and 8 is a y-c separation circuit that separates the color composite video signal supplied to the input terminal 1 into a Y signal and a chroma signal. A Y signal mixing circuit mixes the Y signal from the Y signal generation circuit 5, and 9 is obtained from the chroma signal separated by the y-c separation circuit 7 and the chroma signal generation circuit 6. A chroma signal mixing circuit that completely mixes with the chroma signal, IO is Y obtained from the two mixing circuits 8.9 above.
A Y-C mixing circuit mixes the signal and the chroma signal, and 11 is a video output terminal.

In a signal superimposition device composed of the above,
A color composite video signal as shown in FIG. 2 is supplied to the video terminal 1 from, for example, a color television receiver, and -
1 R, G1 B input terminals receive R, G data from a system other than the receiver, such as a personal computer.
, B signals are supplied, first, the burst gate circuit 2 separates and derives only the burst signal I component of the composite video signal as shown in FIG. be done. On the other hand, in the y-c separation circuit 7, the Y signal component and the chroma signal component are separately derived as shown in FIG. The signals are respectively supplied to the chroma 1 word mixing circuit 9.

At this time, the color subcarrier oscillation circuit 3 oscillates a continuous color subcarrier signal of 3.58 MHz that matches the frequency and phase of the burst signal, and this is transmitted to the chroma signal generation circuit 6.
is supplied to The chroma signal generation circuit 6 uses the R, G1B input terminal 4 FLs 4 b based on the color subcarrier signal.
A chroma signal as shown in FIG. 2 is generated according to the RlG and B signals supplied to the chroma signal mixing circuit 9.

Similarly, in the Y signal generation circuit 5, the input terminals 4a, 4b, 4c
The R, G, and B signals supplied to 031:0.59:
0. Y as shown in Figure 2 Φ) VC mixed at a ratio of
A signal is generated. The Y-signal mixing circuit 8 has two Y-systems obtained from the y-c separating circuit 7 and the Y-signal generating circuit 5.
The signals are mixed to obtain a composite Y signal as shown in FIG. On the other hand, in the chroma signal mixing circuit 9, the y-c separation circuit 7
The two systems of chroma signals obtained from the chroma signal generation circuit 6 are mixed to obtain a composite chroma signal as shown in FIG. At this time, the y-c mixing circuit 10 mixes the composite Y signal and the composite chroma signal, and outputs a color composite video signal as shown in FIG. 2 to the video output terminal 11.

In this way, in this embodiment, the color composite video signal supplied to the input terminal 1 is once separated into a Y signal component and a chroma signal component, and these Y signal and chroma signal are combined with the Y signal and chroma signal generated from separate sources. mixed separately with the signal,
Thereafter, both are mixed, and as a result, one color composite video signal in which the two systems of video signals are superimposed is derived at the output terminal II.

Effect> As described above, according to the signal superimposition device of the present invention, instead of directly mixing two systems of color composite video signals, the color composite video signal is once separated into a Y signal component and a chroma signal component. , since the two systems of Y signal and chroma signal are individually mixed and then both Y signal and chroma signal are mixed to obtain a color composite video signal, mutual interference between the Y signal and chroma signal occurs. This rarely happens, and even when two systems of video are superimposed on the screen, cross-color interference almost never appears as in the past.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the device of the present invention, and FIG. 2 is a signal waveform diagram for explaining the operation of the same embodiment. 1--Video input terminal, 4a, 4b, 4cmR. G, f3 input terminal, 7 - Y-C separation circuit, 8... Y signal, signal mixing circuit, 9 - Chroma signal mixing circuit, 10...
Y-C mixed circuit.

Claims (1)

[Claims] 1 Y-C separation means for separating a color composite video signal into a luminance (Y) signal component and a chroma signal component, and a Y-C separation means for mixing the Y signal separated by the Y-C separation means with a Y signal of another system. a signal means, a chroma signal mixing means for mixing the chroma signal separated by the Y-C separation means and the chroma signal of the different system, and a Y signal obtained from the Y signal mixing means and the chroma signal mixing means. 1. A signal superimposing device comprising: y-c mixing means for mixing the obtained chroma signals, and obtaining a color composite video signal in which two systems of video signals are superimposed.