[time-nuts] 10811 foam enclosure
mikes at flatsurface.com
Mon Jan 10 13:39:44 UTC 2011
At 07:59 AM 1/10/2011, Bob Camp wrote...
>The spec they were after was a warmup to "on frequency +/- 1x10^-8"
>from -40 C sort of thing. I believe the warmup time was under 15
>minutes, but I don't know the exact number.
Nope. It was only spec'd for operation from 0-50C. It was required to
achieve satellite lock within 60 minutes of powerup, but only had to
achieve +/- 1 us (PPS) while locked. Freq spec was < 10E-9 one day
average. You don't even need an OCXO to do all of that.
As I already stated, the warmup/training spec allowed 24 hours, after
which it was expected to be able to holdover for 24 hours within 7 us.
This, while experiencing temperature cycles (0-30C, 20-50C). The
successor, the GPSTM, doubled the warmup to 48 hours, but added an
additional temperature range (35-65C) to the holdover requirement.
The double oven was there for holdover stability, not warmup time.
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