Re: Cinematronics > Atari Adapter???

Well get right on that Rodger! :)

Seriously, I was under the impression that the settling time for the DAC was
determined more by the DAC than subsequent Op-Amps. The DAC7541 seems to have a
settling time of 30 m sec, while the DAC-80s (or DAC7580) have settling times
around 4 m sec.

Unfortunately, even if the DAC was $11 each, you need two, plus the supporting
hardware so your cost is running about $35 in parts alone (gotta include those
connectors). A finished PCB would add another $10 or so. This gets into the
realm of what a Cine monitor board costs (well, usually on the high end as most
operators don't want these monitors at all).

But I agree a 'new' Cine->WG conversion board would be really cool. What's the
cheapest way to go with this?

tm

Rodger Boots wrote:

> You could use something like the DAC7541 which is under $11 even in
> single lots. The op-amp following the DAC will determine the settling
> time. Like Tom says, you can have the DAC only give a positive output
> (in this case by using a negative reference for the DAC) to allow cheap
> switches and subtract out the midpoint (using the same reference voltage
> for best results) to get the desired output swing.
>
> Really nothing much to it.
>
> Tom McClintock wrote:
>
> >Wait, here are some notes from Zonn.
> >
> >------------------
> >Your biggest problem with doing a Cine->WG board is
> >that you are forced to use 12 bit parallel DACs, which
> >are expensive. The Cine design is pretty much going to
> >force you to find ~1 to 2 us settling time parts. (To
> >keep the frame rate up, we had to do the same.)
> >
> >Though you might be able to save some money by using
> >single supply 12 bit DACs and shifting the voltage
> >after the analog switch / RC stuff. This is the
> >approach we took in the ZVG. This also allows the use
> >of the much more available and less expensive 74HC4066
> >switches which are only single polarity switches. The
> >LF13331 were bi-polar, and also expensive (when they
> >were available).
> >
> >You can't use serial DACs. They would require a
> >parallel to serial conversion and there is no time
> >allocated in the hardware to allow this. The DACs are
> >latched and the Z-axis is turned on for the draw,
> >there's no "clock data into DACs" time, which at
> >minimum would take 16 clock cycles, if both DACs were
> >simultaneously clocked.
> >-------------------------------
> >
> >
> >Beyond that, lemme know if you come up with something :)
> >
> >
> >tm
> >
> >
> >
>
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Received on Mon Oct 14 07:19:42 2002