31 Aug
2008
31 Aug
'08
11:01 p.m.
Message: 5
Date: Sat, 30 Aug 2008 15:57:59 -0800
From: Brent Hilpert <hilpert at cs.ubc.ca>
Subject: Re: Ring vs BCD counters for decades
To: General at invalid.domain, "Discussion at invalid.domain":On-Topic and
Off-Topic Posts <cctalk at classiccmp.org>
Message-ID: <48B9DE87.7781F95E at cs.ubc.ca>
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William Donzelli wrote:
> Ranging. For fire control, very accurate ranging is very important, as
> it is one of the biggest variables in ballistics equations. Getting
> accurate range data out of the radars was thus extremely important, so
> the range circuits were very precise, and often employed dividers and
> flip flops and such to generate cursor information on the scopes for
> the operators.
Interesting, I didn't know they had gotten that
complex with the WWII stuff.
Offhand I would have thought they would have used capacitor / pulse-interval
integration techniques for such calculations in that era rather than digital
counters. Not accurate enough perhaps.
(I do have a picture somewhere from WWII of my dad on
a Wehrmacht anti-aircraft
gun that he said was automatically ranged and targetted by radar.)
I maintained Nike Antiaircraft Missile systems in the mid 1950s.
We used a phantastron circuit
http://ed-thelen.org/diagrams.html
to generate a pulse to compare with the timing of the received radar pulse from the
target.
http://ed-thelen.org/ifc_track.html
The range tracking circuits compared the timing of the two pulses
for operator optional automatic range tracking.
This was part of the target range tracking system, which had to be as identical
as possible with the missile tracking system to provide accurate voltage
information to the analog computer for missile steering -
http://ed-thelen.org/computer.html
To help calibrate both range systems, we used pulses from
a 100 KHz crystal controlled oscillator. "worked good ;-))"
(remarkably stable!!)