Zonn wrote:
>If you watch the slow floating of a ship on Space War you can see the ship
>*jump* from one position to the next as it moves across the screen. It's very
>subtle but noticeable. The Cinematronics uses a 1024 x 768 (or thereabouts)
>grid for the starting points of it's vectors -- or about the resolution of
>10bit
>DACs. Since it's noticeable on a 19" screen it would sure be nice to have
>higher resolutions available for the possibilities of larger screens.
Interesting. I never noticed, but I never payed super-close attention
either. I was just happy when I got it working! ;-) I believe it though--
the "jump" in the Sega G-80 rotation system is pretty obvious when you're
spinning "big" objects...
>The disadvantage of 12bits is that your clock rate must be 4
>times faster than the asteroids DVG to maintain the same slew rate -- probably
>not a problem. I wasn't able to find any serial DACs (I didn't do all that
>thorough of a search) that worked at this speed, you might have to stick with
>parallel loaded DACs.
Ehhh, 12MHz vs. 3MHz-- not a big deal. Looks like the device will probably
go out to 40-60MHz withough any trouble...
re: serial DACs...
I was pretty much planning on parallel load DACs. If we went with serial
DACs I start thinking an Analog Devices fixed-point DSP is the smarter way
to do this. (I think that's what Atari used for the third-generation
vector generator that didn't make it out the door...)
Actually, one of our 56K modem chipsets would probably make a pretty
respectable "engine"... ;-)
-Clay
Clayton N. Cowgill Engineering Manager
_______________________________________________________________________
/\ Diamond Multimedia Systems, Inc. clay@supra.com
\/ Communications Division http://www.supra.com/
Received on Thu Dec 18 09:46:06 1997
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