yes that is what I thought, but if I do observe correct, TB's
OCXO does not run at all free for minutes. With a time
constant of 360s the EFC and thePPS is surfing up and
down, why, I do not see the need to shift this OCXO within
2 minutes 80ppbs up and pps15ns as well - with this stable
oscillator....what is the driver, the SATs (I think not so)!
Arnold
First, are these 80ppbs and pps15ns numbers externally
measured by you or internally reported by tboltmon?
It's not that the OCXO runs free for N seconds and then is
corrected and then runs free for another N seconds and is
again corrected, etc. Most GPSDO seem to "continuously"
adjust the DAC. Exactly how much how often depends on
a lot of factors. For example, if you look closely the Z3801A
DAC effectively changes about a hundred times a second:
http://www.leapsecond.com/pages/z3801a-efc/
Play with the TBolt time constant to see what happens. If
you have a particularly stable TBolt and a very stable lab
environment then you should be able to increase the TC
which may improve the shifts that you see. For example:
http://www.leapsecond.com/pages/tbolt-tc/
/tvb
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