Re: Different between color monitors?

[david@wyvern.cc.uow.edu.au (David E A Wilson)]

jpoore@pro-palmtree.cts.com (James Poore) writes:
>A composite color monitor is a monitor than conforms to the NTSC standard
>which has composite video (video, color, sound) at a level of 0-1V.

Correct. 0v = Sync, 0.3v = black, 1.0v = white. Color is encoded by phase
and amplitude modulation of the color burst frequency and added to the luminence
(brightness) signal.

>An Analog RGB monitor has 3 distinct video signals (red, green, blue) that
>form in various amounts to makes all colors.  Each signal is variable from
>0-5V and there is one other signal (sync) which locks the picture.

All the analog models I have seen use either 0.7v or 1.0v signals (depending
on whether they leave room for sync). Some have composite sync on the green
video signal, others have a composite sync pin while still others have separate
horizontal and vertical sync inputs.

>A digital RGB monitor has 5 digital signal lines (red, green, blue,
>intensity, and sync).  It can form only 16 colors (a combination of
>red, green, blue at low intesity for 8 and a combo of red, green, blue at
>high intensity for the other 8).  The digital RGB is not as good as analog
>RGB due to the fact that only 16 distinct colors are availiable, whereas
>the Analog RGB has an infinitely variable color palette.

Some digital RGB monitors have 2 or more inputs per color (ie 2 red, 2 green
and 2 blue gives 4x4x4 = 64 different shades [EGA on a PC I think]). The system
you describe is that used by CGA monitors.
-- 
David Wilson	Dept CompSci Uni Wollongong Australia	david@cs.uow.edu.au