JPS5957286A - Video signal processor - 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 The present invention relates to a video signal processing device, and more particularly to a device that converts data output from, for example, a personal combination coater into a composite video signal that can be displayed on a CRT display or the like.

2. Description of the Related Art Conventionally, devices have been put into practical use that connect a so-called personal computer and a CRT display and display data output from the personal computer on the CRT display. By the way, when different data such as graphic data and character data are overlapped, CR
There are cases where you want to display it on the T display. Therefore,
There was a strong demand for a device that would superimpose data output from two computers and display it on a CRT display.

Therefore, the main object of the present invention is to provide a video signal processing device that can satisfy the above-mentioned demands.

In summary, the present invention includes a first computer and a second computer that adjusts its internal synchronization to a horizontal synchronization signal and a vertical synchronization signal provided from the first computer, and which outputs signals from the first computer. The three primary color video signals and the three primary color video signals output from the second computer are superimposed, and the superimposed video signal is converted into a composite video signal.

The above objects and other objects and features of the invention will become more apparent from the following detailed description with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention.

In the figure, a personal computer 1 outputs video signals R, , G, , B of three primary colors. These signals R1, G, , B are applied to one input of the adder circuit 3. Further, a horizontal synchronization signal and a vertical synchronization signal are outputted from the personal computer 1 and given to the personal computer 2. This personal computer 2
is a computer that requires external synchronization, and the three primary color video signals R2, synchronized with the above-mentioned signals R, , Gl, B,
Exit G2 and B2. These signals R2*02
r 82 is applied to the other input of the adder circuit 3.

As shown in FIG. 2, the adder circuit 3 receives the signals R+, Gl, and B+ from the personal computer 1 as one input of each, and also receives the signals R+, Gl, and B+ from the personal computer 1 as inputs.
31, 32, and 33 receiving signals R2, G2, and B2 from the same circuit as their respective other inputs. Therefore, the OR gate 31 outputs a signal (R1+R2) in which the signals R7 and R2 are superimposed. Further, the OR gate 32 outputs a signal (Gl + Gz) in which the signals G and 02 are superimposed. Also, OR gate 3
3, a signal (BI
+82) is output. The output of the adder circuit 3 is given to an encoder circuit 4.

The encoder circuit 4 includes an adder circuit 3 as shown in FIG.
The three primary color signals from the luminance signal Y and color difference signal (R-Y),
(B-Y), a composite circuit 43 that converts the output of the conversion circuit 41 into a video signal that is a composite of a luminance signal and a carrier color signal, a conversion circuit 41 and a composite circuit 4.
emitter followers 42a, 42 inserted between
b, 42C. The conversion circuit 41 converts 11s<R+Rz), (G, G
buffers 411a, 411b, 4'llc which receive signals (B+ -82) and signals (R1
-R2>, (Gl-Gz), (B1-82), respectively, inverters 412A, 412+1, 41
2c, and a resistor matrix receiving the outputs of the buffers 411a to 411c and the inverters 412a to 412c.
413. Further, the composite circuit 43 includes various circuits as shown in FIG. A horizontal synchronization signal and a vertical synchronization signal from the personal computer 1 are superimposed on the output of the composite circuit 43 via an OR game j.44. In this way, a composite video signal in which the horizontal synchronization signal and the vertical synchronization signal are combined is provided to the emitter follower 45. This emitter follower 45
Meanwhile, a composite video signal of N T sC is extracted. NaJ
3. The output of the R-Y, B-Y mixing circuit in the composite circuit 43 is fed back to the luminance signal and carrier color signal mixing circuit via a bandpass filter 46 and a capacitor C. This bandpass filter 46 is provided to remove harmonic noise components from the composite video signal.

Figure 4 shows the output signals R, , G of the burner computer 1.
It is a waveform diagram showing + and B. FIG. 5 is a waveform diagram showing output signals R21G and 21B2 of the personal computer 2. FIG. 6 shows the output signal @(R+
+R2), (Gl +G2), ”(Bl +8
2) is a waveform diagram showing 2). Note that, for convenience of explanation, FIGS. 4 to 6 are shown so that the respective time axes correspond to each other.

The operation of an embodiment of the present invention will be described below with reference to FIGS. 1 to 6.

First, a horizontal synchronization signal and a vertical synchronization signal are provided from the personal computer 1 to the personal computer 2. Then, the personal computer 2 adjusts its internal synchronization to the applied horizontal synchronization signal and vertical synchronization signal. Therefore, the personal computer 1 and the personal computer 2 output video signals of three primary colors that are synchronized with each other. Next, the output signals R2, Gl, B of the personal computer 1 and the output signals Rt, G2.82 of the personal computer 2 are superimposed by each circuit 3. This superimposed signal is shown in FIG. This n-combined signal (R+
+R2), (Gl +G2>'+(81+82) are converted by the encoder circuit 4 into a composite video signal of a luminance signal and a carrier color signal.Furthermore, horizontal and vertical synchronization signals are converted via an OR gate 44. Superimposed NT
It is considered to be an SC composite video signal. Therefore, when this composite video signal is applied to a CRT display, data in which the data from the personal computer 1 and the data from the personal computer 2 are superimposed is displayed.

As described above, according to the present invention, the data output from two computers are superimposed and converted into a composite video signal, so that the data output from the two computers can be superimposed and converted into a composite video signal. It can be displayed. Therefore, it can be used very effectively when comparing different data.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention. FIG. 2 is a circuit diagram showing details of the adder circuit 3 shown in FIG. 1. FIG. 3 is a circuit diagram showing details of the encoder circuit 4 shown in FIG. 1. FIG. 4 is a waveform diagram showing output signals of the personal computer 1. FIG. 5 is a waveform diagram showing the output signal of the personal computer 2. As shown in FIG. 6th
The figure is a waveform diagram showing the output signal of the adder circuit 3. In the figure, 1 and 2 are personal computers, 3
4 indicates an adder circuit, and 4 indicates an encoder circuit. Patent applicant Sharp Corporation

Claims (1)

[Scope of Claims] A first computer that outputs a first video signal having three primary color signals, a horizontal synchronization signal, and a vertical synchronization signal in order to display input data as an image; The first step is to display the data as an image.
a second computer that outputs a second video signal having three primary color signals in synchronization with a horizontal synchronization signal and a vertical synchronization signal from the computer, the first video signal and the second video signal; A video signal processing device comprising means for superimposing three primary color video signals, and means for converting the superimposed three primary color video signals into a composite video signal.