JPS6046597A - Personal computer - 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 Technical Field The present invention relates to a personal computer capable of mixing composite video signals from an external source.

Recently, personal computers have come to be used in ordinary households. Attempts are now being made to connect a home color television receiver as a CRT display device to a personal computer and display data from the personal computer on the screen of the color television receiver. Furthermore, recently, a combination system of a color television receiver and a personal computer has been developed that displays data from a personal computer superimposed on the screen of a color television broadcast.
Already on the market.

<Prior Art> FIG. 1 shows a schematic diagram of such a combination system. In FIG. 1, 1 is a color television receiver including a color cathode ray tube 2 and a mixing circuit 3, and 4 is a personal computer having a keyboard 5. Desired information is inputted from the keyboard 5 while receiving television broadcasting. Then, this information is appropriately processed within the personal computer 4, and the data is output as R, G, and B signals synchronized with the synchronization signal obtained from the synchronization signal output terminal 1 of the receiver 1, and the R1G% of this personal computer 2. The B signal is sent to the receiver from R, G, and B input terminals 7R, 7c, and 7B.
The mixing circuit 3 in the mixer circuit 3 individually adds the R and G%B signals obtained by receiving and processing the television broadcast, and the added output is supplied to the color cathode ray tube 2. As a result, data from the personal computer 4 is displayed on the cathode ray tube screen superimposed on the broadcast received video.

However, in the combination system as described above, a specially designed television receiver 1 having a synchronizing signal output terminal 6 and a mixing circuit 3 is required as a display device for the personal computer 4, and half f k : +7
The fuser usually cannot be combined with a common television receiver, making such systems very expensive for the user.

Purpose of the Invention The present invention has been made in view of the above points, and is capable of broadcasting by using a commonly used television receiver with a video terminal, without requiring a special television receiver as a display device. To provide a personal computer that can superimpose and display data from a personal computer on a reception screen.

<Examples> The present invention will be described below according to examples shown in the drawings. Second
The figure shows a schematic diagram when a personal computer according to the present invention is used in combination with a color television receiver equipped with a video terminal. Connect to output terminal IO and also external video output terminal 9
is connected to the video input terminal 11 of the television receiver 1, and signals are exchanged between the personal computer 4 and the color television receiver 1 using composite video signals via these input and output terminals.

- FIG. 3 shows an embodiment of the personal computer of the present invention. In FIG. 3, 5 is a keyboard, 12 is a clock pulse generator, 13 is a synchronous controller, and 14 is a character/figure generator, which are not particularly different from those used in ordinary personal computers. Here, we will roughly explain the synchronization separation circuit 15 and the burst gate circuit 1.
6. Color subcarrier oscillation circuit 17, chroma signal generation circuit 18
, a Y signal generation circuit 19, a mixing circuit 20.21, and a mode changeover switch 22.28.

□ A personal computer composed of the above components has a color television receiver [8! When a composite video signal is supplied from II to external video input terminal 8, this composite video signal is supplied to synchronization separation circuit 15 and burst gate circuit 16, and is also supplied to mixing circuit 21 via changeover switch 23.

At this time, the synchronization separation circuit 15 separates horizontal and vertical synchronization signals from the composite video signal and applies them to the synchronization controller 1B. On the other hand, the burst gate circuit 16 gates only the burst signal in the composite video signal based on the horizontal synchronization signal from the synchronization separation circuit 15.
Added to 7.

At this time, the oscillation circuit 17 oscillates a color subcarrier signal of 8.58 MHz in synchronization with this burst signal, and supplies it to the chroma signal generation circuit 18. The synchronous controller 1B is synchronously driven based on clock pulses from the clock pulse generator 12 and horizontal and vertical synchronization signals from the synchronous separation circuit 15.
When desired information is input to 3, data such as characters and figures according to the information is separated into R, G, and B signals and derived from the character and figure generator 14, and these signals are sent to the chroma signal generation circuit 18 and the Y The signal is supplied to the signal generation circuit 19. Furthermore, R
%G, B signals are R%G, B output terminals 24R, 24c,
24B. The chroma signal generation circuit 18 generates chroma signals according to the R%G and B signals shown below based on the color subcarrier signal from the color subcarrier oscillation circuit 17, while the Y signal generation circuit 19 generates a Y signal. The chroma signal and the Y signal are mixed in the mixing circuit 20 to generate a composite video signal. The composite video signal obtained from the mixing circuit 20 is supplied to the mixing circuit 21 via the changeover switch 22, where it is mixed with the composite video signal from the color television receiver obtained from the external video input terminal 8, and the external video signal is mixed with the composite video signal from the color television receiver obtained from the external video input terminal 8. A composite video signal in which the two signals are mixed is derived from the output terminal 9.

If the composite video signal thus led out to the external video output terminal 9 is supplied to the video input terminal 11 of a normal color television receiver 1, the television broadcast reception will be displayed on the screen of the cathode ray tube 2 of the receiver 1. Data corresponding to input information from the personal computer 4 is superimposed and displayed together with the video.

Here, the mode changeover switches 22 and 23 are arbitrarily turned on and off based on commands from the synchronous controller 13 by changing modes through input operations from the keyboard 5.
If only the switch 22 is turned on, only the data from the personal computer 21 can be displayed on the cathode ray tube screen of the receiver 2, and conversely, if only the switch 23 is turned on, the data from the personal computer 21 can be displayed on the cathode ray tube screen of the receiver 2. This system blocks out all other data and displays only the original television broadcast images received by the color television receiver on the cathode ray tube screen.

<Effects> As described above, according to the personal computer of the present invention, it can be used with commercially available television receivers with video terminals without using a special mixing device or a dedicated color television receiver as in the past. By combining, it becomes possible to simultaneously display the personal computer data on the receiver screen by superimposing it on the broadcast received video.

Note that the personal computer of the present invention can be connected not only to a TV set, but also to other video equipment such as a video tape recorder or a video printer.

[Brief explanation of drawings]

FIG. 1 is an outline diagram of a system in which a conventional personal computer and a color television receiver are combined, and FIG. 2 is an outline diagram of a system in which a personal computer and a color television receiver according to the present invention are combined. 8 are block diagrams of the personal computer of the present invention. 8... External video input terminal, 9... External video output terminal, 12... Clock pulse generator, 1B... Synchronous controller, 14... Character/figure generator, 15...
... Synchronization separation circuit, 16 ... Burst gate circuit, 1
7... Color subcarrier oscillation circuit, 18... Chroma signal generation circuit, 19... Y signal generation circuit, 20.21...
mixed circuit.

Claims (1)

[Claims] 1. An external video input terminal, an external video output terminal, means for separating horizontal and vertical synchronization signals from a composite video signal supplied to the external video input terminal, and means for separating a burst signal from the composite video signal. and means for oscillating a one-color subcarrier signal based on the burst signal separated by the means, and characters, figures, etc. according to input information from the cow board based on the horizontal and vertical synchronization signals. means for generating data based on the color subcarrier signal, means for generating a composite video signal according to the data based on the color subcarrier signal, and a means for generating a composite video signal generated by the means and supplied to the external video input terminal. What is claimed is: 1. A personal computer comprising: means for mixing a composite video signal mixed by the means; and an external video output terminal for outputting the composite video signal mixed by the means.