[time-nuts] Tbolt issues
ewkehren at aol.com
Sun Sep 11 14:25:17 EDT 2016
Know all that that is why we decided not to do it. Not knowing all the ins and outs and limits of the Tbolts that is why I asked the question to begin with
Sent from Samsung tabletCharles Steinmetz <csteinmetz at yandex.com> wrote:Bert wrote:
> On our to do list was temperature control and clean up loop. In order to do
> an analog clean up we need short interval changes and that is why I went
> on the list since we have not been able to do it and looking at past posting
> have not found data that will get us there.
To do any kind of "cleanup" at tau=1S, you need a source that is better
at that tau than the one you are trying to clean up. But if you have
that, why use it to clean up something else? Just use it as your
standard. (One might respond that the point would be to use the Tbolt
to discipline the better oscillator at longer tau to correct drift, but
you would need a very long time constant -- thousands of seconds --
which you cannot achieve with an analog loop.) I do not think there is
any realistic possibility of doing the kind of cleanup you propose in
the analog domain.
Are you absolutely certain you tried the Tbolt with the damping set to
10 seconds or more? Did you let it settle for several weeks before
deciding it wasn't doing what you need?
Perhaps you can try one last time:
1. Do a hard reset back to factory settings
2. Change TC to 500 seconds and damping to 10-12
3. Set recovery jam synch to "ON" with a threshold of 55-65 nS
4. Set recovery max offset frequency to >=1000 (this is in ppb)
5. Put it in an undisturbed location, inside a box of some kind
6. Let it sit for a month
7. Now, measure it
If this is better, but not quite good enough, try damping settings of 30
Alternatively, for a 10MHz reference you can just forget about and use,
buy another PRS10 and discipline it with the PPS from the Tbolt. I'd
recommend buying a new one from SRS so you know that it has the PPS
discipline feature and you could get help from SRS to optimize the
discipline for your needs (the discipline is very adjustable and it is
easy to get confused).
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