Re: Apple ][gs VGA Card

[blakjak@panix.com (Noah Mittman)]

AURI MAN (aar7334@exodus.valpo.edu) screamed from comp.sys.apple2:
: Ummm... just for us lamen's, could you tell us what the difference between
: interlaced and non-interlaced is? :)

Well, it describes the method of how the scan lines are drawn on the
monitor. In TV, the screen is interlaced as fields - 60 fields / sec,
30 frames / sec. Only the odd lines are filled in, and then the even
lines, to make the full frame. For TV, since they decided to use AC
current to time the sets (60Hz) it was the only way to remove flicker
and use the phenomenon of "persistance of vision" - like when you stand
in a dark room and suddenly turn out the light, your perception of the
light would fade out, and not just instantly cut off - to make it seem
as if the picture moved fluidly. As you still saw the odd field, the even
field would appear, and vice versa.
Same thing goes for computers, but they're not limited to odd or even
fields, or even the same timing. If a monitor gun draws from the top to
the bottom, it's non-interlaced. If it has any system of skipping lines
or sections and going back to them later, it's interlaced.

-- 
noah [blakjak@panix.com] | <tankPolice!>
belong to us and we'll make you select() on ptys
"but if the answer isn't violence / neither is your silence" - pwei