Info, spice model parameters for DEC pulse transformers?
v.slyngstad at frontier.com
Wed Jul 18 08:39:13 CDT 2018
From: Joseph Oswald: Wednesday, July 18, 2018 12:15 AM
> I'm trying to model the PDP-1 DEC system models, first with SPICE
> (ngspice on Linux), then with VHDL.
The spice modeling of flip-chip modules has been an interest area
for me. I imagine that's similar, though perhaps less daunting, than
modeling the earlier system modules. Flip chip schematics, etc. can
be found here:
and some of the spice model stuff here:
Particularly a parts library and the Perl to extract information (netlists)
from the Eagle schematics. There are sub-directories with results
from the Perl for red and blue handled modules, and a few of the
green. Finding data to fill in the component model library is "fun",
as the parts are long obsolete, and data sheets are hard to find.
I also lack the EE skills to be effective at converting the data sheets
into spice models, even when I can find them.
Your first "fun" step might be to locate module schematics and
convert them to a useful form.
> I'm struggling to understand the properties of various transformers in
> the system module circuits, most importantly (at least, the ones I see
> in schematics I want to model)
Those are all earlier than the info that I have, which is mostly for
the T2037 and T2052. Perhaps the earlier ones are wound on
a similar core, or the measurement technique Josh and I used
can be used to begin to reverse engineer them:
> Is there any source for information about these? Basic specs? I don't
> even know what the turns ratios are for these parts, much less
> plausible inductances, so my spice models misbehave pretty badly.
Unfortunately, the schematics don't usually state the relevant specs
(just part numbers), so it may be necessary to measure up originals.
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