Question and misc...

Hi everyone.

Rainy as all hell here last weekend so I got some time in on
game-projects...

Question: What's a reasonable price to ask for a new yoke for a B/W XY
monitor? (Selling one to somebody and I don't want to be too high, or
too low either... ;-)

Misc #1: In my rather limited testing, it seems that a MC68A09EP
processor (the slower rated sibling of the MC68B09EP used in Star Wars)
will work just fine in a Star Wars CPU board. I only had two to try,
but both seemed to work fine. YMMV

Misc #2: I did some tinkering in Electronics Workbench modeling the
behavior of the Cinematronics "bloom-clamp". It's kinda neat. Analog
design is pretty funky stuff to me, so I needed to *see* what it was
doing to actually understand it.

http://www.e-volve.net/~clay/cinemat.gif

...is a "virtual" o-scope trace of the bloom-clamp in action on a 1KHz
triangle wave. The blue trace is the "ideal" triangle wave, the red
trace is the output of the bloom-clamp. The bloom-clamp provides gain
on the input signal, so the scales for the input and output waves are
different. Essentially the circuit provides a fairly linear gain
characteristic (with a little bit of boost to low voltages), but the
gain starts to roll off as the input voltage increases. For low input
voltages the gain is close to 2:1, but as the input voltage increases
the gain drops off in a "curve" like fashion.

I suppose this would have the effect of "pulling in" parts of an image
near the edges of the CRT (near the edge of deflection where input
voltages are greater). It also looks like it might cause a little
distortion of its own near the center of the screen though too... I'm
going to try to hack it into one of the Display Corrector PCB's instead
of the "standard" feedback resistor. See what happens. ;-)

-Clay

Clayton N. Cowgill Engineering Manager
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/\ Diamond Multimedia System, Inc.
\/ Communications Division
Received on Mon May 18 11:11:14 1998