[sdiy] presets on a modular

[harrybissell]

>On Fri, 12 Nov 2004 09:50:26 -0000 "Paul Maddox"
<P.Maddox at signal.QinetiQ.com> wrote.

>Why?
>You could have 4 supply lines,
> 15V,  5V,  3.3V and -15V and two grounds, one analogue, one digital.
>As long some basic precautions are taken there is no need to limit a system
>by saying it can only have one PSU.

its not efficient. If you have to do level translation all the time you
will have a lot of problems to overcome.

JH made a point some years ago about using the 'natural' signal levels
of the circuits themselves (for example, no filter circuit REALLY runs
+/-10V ... internally they are more like 50mV).  That would be OK
for the 5V logic.

H^) harry