Being "hardware oriented" it seems they had a lot of stray capacitance
and inductance with no ground plane, therefore "non controlled
impedance. Just basing in my RF intuition.
I guess it wouldn't be too well controlled, but the ttl bus drivers of the
day seemed to match wirewrap backplanes fairly well. The waveforms looked good
on a scope anyway, fwir, but bus speeds were only in the low Mhz at the time.
At this time i characterized back panel daughter boards connectors using TDR
reflectometers. Very interesting results.
That does sound interesting, though I assume that you matched the tdr source
Z with the connecter characteristics ?. Sounds like an order of magnitude or
two faster than unibus or qbus, and signals through the connector would be
significant. I still have a tdr plugin for tek 7000 series scope, though haven't
used it for a long time. 1970's technology and it can detect a 0.25" or less
piece of hardline or sma T no problem. 30pS risetime and not bad for what was
a design using 60's technology. Tek were very, very good at that time and way
ahead of the curve.
Am droning on a bit again, but, to bring back on topic, found a very interesting
discussion on tech log re aircraft testing and stall:
http://www.pprune.org/tech-log/17316...ver-stall.html
Definately worth a read, imho, but prepare to be disturbed
...