Ring vs BCD counters for decades

William Donzelli wdonzelli at gmail.com
Sat Aug 30 18:11:00 CDT 2008

> 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.

Various sets used various techniques, but it all boiled down to
putting accurate cursor marks on the scopes. By the end, there were
some pretty amazing things happening.

In a few years - the early 1950s - the IFF sets were SIF encoded,
where each aircraft or ship, when interrogated by a radar, would reply
with an octal pulse code 0000 to 3777. The interrogating radar would
then read the pulses, compare them to the code of the day, and modify
the video to the scopes automatically (AN/UPX-1, AN/APX-25, AN/UPA-24,
for those paying attention) to the operator could call the shots. I
think there are remnants of this ancient system still in use.


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