[time-nuts] HP Z3801 RB fun

Magnus Danielson magnus at rubidium.dyndns.org
Tue Dec 27 21:01:41 EST 2016


Have you matched up the Rb EFC sensitivity to that of the 10811.
If not, you have most probably grossly changed the loop gain, and I 
can't recall that the Z3801A was designed to have different loop-gains.

Just a thought.


On 12/28/2016 02:33 AM, paul swed wrote:
> OK so could not resist. The replacement of the HP 10811 with a PIEZO ocxo
> went very well. So in for a penny in for a pound. Why not an RB. Having a
> few around. Choice efratom FRS-c. Lot of thought went into this choice. Not
> really it was there. It has a inverse frequency to EFC voltage just like
> the piezo and opposite the HP 10811.
> Well it connects runs and locks using the simple 1 opamp level ofset and
> and phase inverter.
> But locked is a funny comment. According to HPsatstat and LH. Its pll is
> locked. But both scope and the LH graph shows a very slow frequency drift
> that with the offset I can make positive or negative. A cycle at 10 ns
> takes quite some time about an hour compared to a TBolt and another non
> modified Z3801. At this level of resolution some things start to become
> questionable.
> I almost wonder if the modified z3801 under some level of drift assumes
> everything is locked and fine. Can it be pushed beyond expectations. I
> suspect it can.
> Anyhow as I say a bit of GPSDO fun.
> Regards
> Paul
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.

More information about the time-nuts mailing list