[time-nuts] CSAC Project(was CSAC purchase)

[Ronald Held]

Nigel;
   Will read the PDF carefully.
      Ronald


 "if it runs for years (or even months)" sounds like an informed comment:-)

When searching for some data recently I came across a report which
might be relevant.

"A Second Look at Chip Scale Atomic Clocks for Long Term Precision
Timing", written by
Alan T. Gardner and John A. Collins of the  Woods Hole Oceanographic
Institution, details their
experience with a number of earlier and more recent CSAC modules and
their findings make
for very interesting reading.

At the time of writing a copy is available here....

www.obsip.org/documents/Gardner_IEEE_Oceans_2016.pdf


Tim:
   Only three times worst then CSACs?
       Ronald


y those Woods Hole guys.

Their temperature-compensated 5 milliwatt crystal oscillators can be
back-corrected (linear drift model) to a few tens of milliseconds over a
year and they make a convincing case they know how to do this.

Their similar graphs for CSAC oscillators are maybe a factor of three
better.

Tim N3QE

Bob:
  Does it make sense to reset yearly if the offset is milliseconds?  Tenths?
       Ronald


Actually it was not quite what it sounded like. What I was trying to
say was “free runs”
for years or even months. Any device that is re-calibrated will have
the aging drift zeroed
out in that process. As noted in another post, CSAC’s have gone
through some growing
pains. The Woods Hole paper came out sort of at a low point in the process. The
current crop of CSAC parts seem to be more reliable than the ones Woods Hole
reported on. I’ve seen failures over the years, but not a lot of them ….

Bob


Tom:
   That PDF was interesting.  Not certain I would've one.
     Ronald


> www.obsip.org/documents/Gardner_IEEE_Oceans_2016.pdf

Also see the very nice presentation:

"Challenges of precise timing underwater"
http://www.ipgp.fr/~crawford/2017_EuroOBS_workshop/Resources/Gardner_OBS_Timing_ATG_20150427.pdf

/tvb