Applications Information
Figure 4
shows the block diagram of a typical analog RGB
color monitor The RGB monitor is used with CAD CAM
work stations PC’s arcade games and in a wide range of
other applications that benefit from the use of color display
terminals The RGB color monitor characteristics may differ
in such ways as sweep rates screen size CRT color trio
spacing (dot pitch) or in video amplifier bandwidths but will
still be generally configured as shown in
Figure 4
Separate
horizontal and vertical sync signals may be required or they
may be contained in the green video input signal The video
input signals are usually supplied by coax cable which is
terminated in 75X at the monitor input and internally ac cou-
pled to the video amplifiers These input signals are approxi-
mately 1 volt peak to peak in amplitude and at the input of
the high voltage video section approximately 6V peak to
peak At the cathode of the CRT the video signals can be as
high as 60V peak to peak One important requirement of the
three video amplifiers is that they match and track each
other over the contrast and brightness control range The
Figure 4
block labeled ‘‘VIDEO AMPLIFICATION WITH
GAIN AND DC CONTROL’’ describes the function of the
LM1203 which contains the three matched video amplifiers
contrast control and brightness control
TL H 9178 – 4
FIGURE 4 Typical RGB Color Monitor Block Diagram
http
www national com
6
NSC [ NATIONAL SEMICONDUCTOR ]
