[time-nuts] using Fury GPSDO with Rb
smace at intt.net
Fri Apr 18 14:29:21 EDT 2008
Here's what I ended up with:
COARSE DAC : 105
DAC GAIN: 1200.00
EFC SCALE : 1.40
EFC DAMPING: 2
OCXO SLOPE : POSITIVE
TEMPERATURE COMPENSATION : 0.00
AGING COMPENSATION : 0.02744
PHASE CORRECTION : 35.000000
Here are some plots:
Everything is on an open work table right now, with the LPRO mounted on a
heatsink. The baseplate of the LPRO is about 38C. I have not tried too
much to adjust EFC damping either, it seemed that if it had more than 10 it
would become unstable.
SAIDJACK at aol.com wrote:
> Hi Scott,
> that's a great success story!
> What final Loop settings do you use on the Fury with LPRO-101?
> It would be interesting to see if the +-10ns temperature related deviations
> are coming from the LPRO or maybe the GPS, DAC etc? What is the EFC change
> over these temp changes?
> With the external clock source, it is not easy to use the temperature
> compensation of the Fury, but it could be done - need a current sink that is
> sensitive to temperature and uses about 50 - 200mA, that can be used as a highly
> accurate temperature sensor for the compensation routines.
> The digital temperature sensor on the Fury has only 1/16 Deg C resolution,
> not nearly enough to do accurate temperature compensation.
> In a message dated 4/18/2008 09:21:01 Pacific Daylight Time, smace at intt.net
> It's working well with the LPRO-101. It stays typically within +-3ns
> with excursions to +-10ns based on temp changes (hvac cycling, etc.)
> It is very apparent when you plot the temp sensor on the fury.
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