[time-nuts] Looking for info about first true radio controlled clock

jimlux jimlux at earthlink.net
Tue Feb 22 13:34:53 UTC 2011


On 2/21/11 10:12 PM, Michael Lombardi wrote:
> I'm trying to determine the first product that could automatically
> decode and display a digital time code.  Digital time codes were
> added to WWV in 1960 and WWVB in  1965.  This was before they were
> added to any satellite  signals, or before they were added to LF
> stations in Europe, such as DCF77.  Telegraphic time codes, of
> course, were around much earlier.
>

the IRIG standaards started in the late 50s, and I'm pretty sure that
they used time code when recording on instrumentation recorders earlier
than that. You'd record a bunch of analog signals using FM on a
multitrack recorder, and because the playback speed varies and the tape
stretches, you need something to recover actual timing.

the first instrumentation recorders were used in the late 40s or early 50s

there's also a famous spread spectrum system used during WW2 with 
identical phono records with random noise, but I think those were sync'd 
by hand.


> I currently think the first true radio controlled clock that decoded
> a digital time code was the Develco 3391, introduced around 1969.  It
> received WWVB signals and was used by the electric power industry.
>
> Does anyone know of anything earlier?  Also, has anyone seen a
> Develco 3391 or have a good picture of one?
>
> Any help would be appreciated.
>
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