JPH11133940A - Interface of personal computer main body and crt display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To connect a personal computer main body and a CRT display device to each other with one signal line by dividing the NTSC type image signal into the horizontal vertical synchronous signal and the analog Red, Green and Blue signal, and supplying them to an internal circuit of a CRT. SOLUTION: A compound circuit 2 of a personal computer main body 1 compounds each Red, Green and Blue signal of the digital signal and the VSYNC.HSYNC signal of the vertical.horizontal synchronous signal so as to change them to the image signal, which can be transmitted by one signal line similarly with the NTSC type composite video signal. The image signal output by one signal line is divided into the digital signal and the synchronous signal again by a dividing circuit 4, and the digital signal is changed to the analog RGB at need, and supplied to a CRT internal circuit 6 so as to be used for the internal signal. With this structure, interface of the personal computer main body 1 and the CRT display device 3 can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connection interface between a personal computer main unit and a CRT display device, and more particularly to an interface between a personal computer main unit and a CRT display device for transmitting an image signal through one signal line.

[0002]

2. Description of the Related Art A conventional personal computer body and C
The connection interface with the RT display device is a 15-pin D
_SUB or mini D_SUB connector is connected by a multi-wire cable composed of at least five signal lines to transmit a color image signal. The signals actually used are VSYNC, HSYNC except for the GND signal.
C, Analog Red, Analog Green, Analog B
lue five signals. The multi-wire cable has a large number of signal lines and a relatively large connector.

[0003]

The first problem is that since each signal is transmitted individually, the number of cables to be connected is large, and the cost of the cables increases.

[0004] The second problem is that since there are many signal lines, the connectors used for connection are large, which is disadvantageous in terms of mounting.

An object of the present invention is to replace a conventional multi-wire cable with a cable composed of one signal line with a composite image signal in the same manner as an NTSC system image signal.

[0006]

SUMMARY OF THE INVENTION Therefore, according to the present invention,
A personal computer body that connects the personal computer body and the CRT display device with a multi-wire cable including five signal lines for transmitting a horizontal synchronization signal, a vertical synchronization signal, an analog Red signal, an analog Green signal, and an analog Blue signal, respectively; In the interface of a CRT display device, the horizontal synchronization signal, the vertical synchronization signal, and the analog Red
A composite circuit for converting a signal, an analog Green signal, and an analog Blue signal into an NTSC image signal, a signal cable for transmitting the NTSC image signal, and the NTSC signal received through the signal cable.
And a separation circuit for separating the system image signal into the horizontal synchronization signal, the vertical synchronization signal, the analog Red signal, the analog Green signal, and the analog Blue signal, and supplying the separated signals to a CRT internal circuit.

Further, the signal cable is a coaxial cable comprising one signal line.

[0008] A red, green, digital signal of a digital signal is provided by a composite circuit provided in the main body of the personal computer.
Each signal of Blue, the VSYNC signal of the vertical synchronization signal, and the HSYNC signal of the horizontal synchronization signal are compounded, and
The video signal is converted into an image signal that can be transmitted through one signal line similar to the composite video signal of the TSC system. The image signal output from one signal line is converted into red, green, and blue digital signals by a separation circuit provided in a CRT display device.
ue signals and the synchronization signal VSYNC signal, HSYNC
The C signal and the C signal are separated again, and the digital signal is changed to analog RGB if necessary, supplied to the CRT internal circuit, and used for the internal signal. As a result, an interface between the personal computer main unit and the CRT display device can be obtained with one signal line.

[0009]

Next, an embodiment of the present invention will be described with reference to the drawings. Referring to FIG. 1, as a preferred embodiment of the present invention, a composite circuit 2 inside a personal computer main body 1, a separation circuit 4 inside a CRT display device 3, and a cable connecting the main body 1 and the device 3 are shown. And 10. The CRT display device 3 has a digital Red, Green, and Blue digital R based on a composite video signal received through the cable 10.
D / A for converting the GB signal 7 into an analog RGB signal 8
A converter 5 and a conventional C that constitutes the CRT display device 3
An analog RGB signal 8, a horizontal synchronizing signal and a vertical synchronizing signal 9 connected to the RT internal circuit 6 are included. The composite circuit 2 and the separation circuit 4 are the same kind of circuits used for the NTSC type receiver in TV broadcasting adapted to the synchronization method and resolution of the image output of the personal computer.

Next, the operation of this embodiment will be described with reference to FIGS. 2, 3 and 4. FIG. 2 is a timing waveform of an image signal in this embodiment. It is basically the same as the composite video signal of the NTSC system, but the differences are as follows. The frequency of VSYNC depends on the display mode of the personal computer main body 1, and is 60 Hz at 60 Hz and 75 at 75 Hz.
Hz. The number of HSYNCs is equal to the number of scanning lines in the display mode of the main body 1. For example, 1024 dots x 7
For 68 lines, 768HSYNC during 1VSYNC
There are C scan lines. Also, the display data 2 in FIG.
1, a horizontal front porch 22, a horizontal synchronization pulse 23, and a horizontal back porch 24 are similarly adapted to the display mode.

FIG. 3 shows VSY which is a vertical synchronizing pulse 32.
In the composite video signal of the NTSC system, VSYNC has a width equivalent to three HSYNCs, an equivalent pulse equal to three HSYNCs before VSYNC, and an equivalent pulse equivalent to three HSYNCs after VSYNC. In this embodiment, the equivalent pulses 32 before VSYNC depend on the display mode of the main body 1 and have the same number of HSYNCs as the vertical front porch 31. Also, V
The equivalent pulses after the SYNC also have the same number of HSYNCs as the vertical back porch 33. VSYNC is the same number of HSYNCs as the width of the vertical synchronization pulse 32.

FIG. 4 shows the HSYNC of the horizontal synchronization pulse 42.
The signal waveforms in the vicinity are of the NTSC composite
For video signals, HSYNC is 4.7us ± 0.1u
s, the front porch is 1.5 μs ± 0.1 μs, and the back porch is 4.7 μs. In this embodiment, all depend on the display mode of the main body 1. For example, HSYNC
42 is 2.542us, and the horizontal front porch 44 is 0.10us.
675us, horizontal back porch 46 is 3.138us,
Then, each horizontal front porch 44 is 0.67
5us, the horizontal back porch 46 becomes 3.138us. Similarly to the composite video signal of the NTSC system, a 9-cycle color burst 43 is inserted into the horizontal back porch 46. In one horizontal line, color information of the number of dots corresponding to the display mode is multiplexed.

[0013]

The first effect is that the number of signal lines can be reduced to one. The reason is that, in the prior art, using a 15-pin D_SUB or mini D_SUB connector, except for the GND signal, VSYNC, HS
Although five signal lines of YNC, analog Red, analog Green, and analog B1ue have been used, the present invention can connect the personal computer main body and the CRT display device with one signal line except for the GND signal. Because.

The second effect is advantageous in terms of mounting because a connector used for connecting a CRT display device can be small. The reason is that the present invention can reduce the size of the connector because only one signal line is required.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing a timing waveform of horizontal synchronization of an image signal in FIG. 1;

FIG. 3 is a signal waveform showing a vertical synchronization signal of the image signal in FIG.

FIG. 4 is a signal waveform showing a horizontal synchronization signal of the image signal in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Personal computer main body 2 Composite circuit 3 CRT display device 4 Separation circuit 5 D / A converter 6 CRT internal circuit 7 Digital RGB signal 8 Analog RGB signal 9 Horizontal synchronization signal and vertical synchronization signal 10 Cable

Claims (2)

[Claims] 1. A personal computer main body and a CRT display device are connected to each other by using a horizontal synchronizing signal, a vertical synchronizing signal, and an analog signal.
ed signal, analog Green signal, and analog Blue
An interface between a personal computer main unit and a CRT display device connected by a multi-wire cable including five signal lines each transmitting a signal, wherein the horizontal synchronizing signal, the vertical synchronizing signal, the analog Red signal, and the analog Gre signal are provided to the personal computer main unit.
NTSC by combining the “en” signal and the analog Blue signal.
A composite circuit for converting the NTSC image signal into an image signal, an NTSC image signal received through the signal cable, the horizontal synchronization signal, the vertical synchronization signal, the analog Red signal, and the analog signal. Green signal and analog Blu
An interface between a personal computer main unit and a CRT display device, comprising: a separation circuit for separating the signal into an e-signal and supplying the separated signal to a CRT internal circuit. 2. The interface between a personal computer main unit and a CRT display device according to claim 1, wherein said signal cable is a coaxial cable comprising one signal line.