Computer graphics processing and selective visual display system – Display driving control circuitry – Display power source
Reexamination Certificate
2000-03-22
2003-12-02
Chow, Dennis-Doon (Department: 2675)
Computer graphics processing and selective visual display system
Display driving control circuitry
Display power source
C345S011000, C348S572000
Reexamination Certificate
active
06657623
ABSTRACT:
CLAIM OF PRIORITY
This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. §119 from an application entitled METHOD FOR SENDING IMAGE SIGNAL earlier filed in the Korean Industrial Property Office on Jul. 13
th
1999, and there duly assigned Serial No. 99-28202.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method and apparatus for transmitting a video signal, and more particularly, to a method and apparatus for transmitting a video signal by processing a video signal from a computer and inputting the processed signal to a cathode ray tube (CRT) monitor.
2. Description of the Related Art
In a typical computer, a graphic controlling unit controls a video random access memory (RAM) according to a control signal, an address signal and a data signal from a central processing unit (CPU) to generate a parallel digital video signal. The parallel digital video signal is converted to an analog video signal and then is transmitted to a cathode ray tube (CRT) monitor.
Referring to
FIG. 1
, a video card of a conventional computer
100
includes a graphic controller
11
, a video random access memory (RAM)
12
, a clock pulse generator
13
and a digital-to-analog converter (DAC)
14
. The graphic controller
11
reads or writes data from or to an input address (ADR) area of the video random access memory (RAM)
12
by means of a read/write signal (R/W) according to a control signal (CTR) output from the central processing unit (CPU)
10
of the computer
100
. The graphic controller
11
and the digital-to-analog converter (DAC)
14
operate according to a clock pulse signal (CLK) output from the clock pulse generator
13
.
The graphic controller
11
processes data output from the video random access memory (RAM)
12
to generate a parallel digital red video signal R
P
, a parallel digital green video signal G
P
, a parallel digital blue video signal B
P
, a horizontal sync signal H
SYNC
, a vertical sync signal V
SYNC
and a data enable signal DE.
The digital-to-analog converter (DAC)
14
processes the parallel digital signals output from the graphic controller
11
to generate an analog red video signal R
A
, an analog green video signal G
A
, an analog blue video signal B
A
, and an analog synthesized sync signal SYNC
A
. The analog signals output from the digital-to-analog converter (DAC)
14
are transmitted to a monitor
110
via a metal cable
15
.
An amplifier
16
of the monitor
110
amplifies the received analog video signals R
A
, G
A
, and B
A
and inputs the amplified signals R
A
, G
A
, and B
A
to a cathode ray tube (CRT) driver
18
of monitor
110
. Also, a synchronization controller
17
of monitor
110
controls the received analog synthesized sync signal SYNC
A
to input this controlled signal to the cathode ray tube (CRT) driver
18
.
According to the conventional transmission method, the parallel digital video signals are transmitted as converted analog signals. Thus, noise externally generated affects the transmission of the analog signals so that the video signals are easily distorted during the transmission period.
SUMMARY OF THE INVENTION
To solve the above problem, it is an objective of the present invention to provide a method and apparatus for transmitting a video signal from a computer to a cathode ray tube monitor by processing the video signal so that the rate of distortion of the transmitted video signal can be reduced.
Accordingly, to achieve the above objective and other objectives of the present invention, there is provided a method of and apparatus for transmitting parallel digital video signals output from a graphic controller of a computer to a driver of a cathode ray tube monitor, transmission being achieved by converting the parallel digital video signals to serial digital video signals, transmitting the converted serial digital video signals to the cathode ray tube monitor via a cable, converting the transmitted serial digital video signals to serial analog video signals, and inputting the converted serial analog video signals to the driver of the cathode ray tube monitor.
REFERENCES:
patent: RE33916 (1992-05-01), Saenz et al.
patent: 5798720 (1998-08-01), Yano
patent: 5949495 (1999-09-01), Tallman et al.
Digital Display Working Group, “Digital Visual Interface DVI, Revision 1.0”, Apr. 2, 1999, pp. 11, 24-27 and 30.*
Silicon Image documents “All-Digital Solutions for All-Digital Displays” and “Hitachi Launches First All-Digital Desktop PC Family in Japan Using Silicon Image's PanelLink Technology”.
Bushnell , Esq. Robert E.
Chow Dennis-Doon
Sam-Sung Electronics Co., Ltd.
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