[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Commodore 1960 monitor work with IIgs?
Polymorph wrote:
Michael J. Mahon wrote:
Although most games will look great on a composite color display,
you will not be able to read the GSOS desktop, nor 80-column text.
Michael, I'm guessing this is why all the work is being done to get the
IIgs working with VGA and LCD monitors? Are there any other monitors
out there that share the IIgs's RGB monitors interface?
I thought that there was a list compiled of the most common NTSC-scan
analog RGB-capable monitors, and that it was in the CSA2 FAQ...
I might be opening up a can of worms here, but why is the clarity so
bad using composite? Is there limited bandwidth or excessive noise or
something? Is the composite output from the IIgs different from the //e
et al? I thought when the IIgs was originally introduced in '86, the
//e-->//gs upgrade kit could be used with the existing //e monitor. Did
Apple just not think clearly, or was it a clever plot to force these
users into buying a IIgs RGB monitor?
This topic comes up enough that it should also be in the FAQ if it
isn't.
Composite video uses a chroma subcarrier to carry the color information,
with a subcarrier frequency of 3.58MHz. Older analogmonitors use a
simple LC filter to lowpass the luminance (B&W) part of the composite
signal to eliminate frequencies above 3MHz. Since the luminance signal
contains the "detail" of the picture, resolution of a composite video
signal is generally limited to about 3MHz, or, generously, 300 pixels
across a line. Apple II 80-column text (and DHR) uses 560 pixels per
line, so details at this resolution are quite blurred, making, for
example, 80-column text unreadable.
-michael
New, faster SUDOKU v2.0 solver for Apple II's!
Home page: http://members.aol.com/MJMahon/
"The wastebasket is our most important design
tool--and it's seriously underused."