8 Nov
2007
8 Nov
'07
11:18 a.m.
Eric J Korpela wrote:
There's a line of chip from Analog Devices, AD273/AD274/AD275 and others,
which will convert from RGB to NTSC/PAL. It gives composite and split video
outputs. They're in the US$5 range. Perhaps this could be used with my
previous circuit that converts TTL to analogue?
Alexis.
I've had luck with converting the RGB to VGA
and then converting the
VGA to NTSC using both this sort of device
(http://www.genao.com/converters.htm) and this
(http://www.converters.tv/products/cga_to_vga/425.html (Warning,
expensive))
Not cheap, but when it needs to be done, it needs to be done.
converters.tv does have a CGA to NTSC converter that they are offering
for 110 AUD (~$100 US)
(http://www.converters.tv/signals/cga_to_ntsc.html)
Unfortunately both the converters.tv units ignore the "intensity" pin of
CGA, which means that only 8 of the 16 colors can be displayed from an
IBM CGA card. :-( This is the bit (pun intended) missing from all
converters I've come across, unfortunately.