[time-nuts] Disciplining Rubidium

Tom Duckworth tomduck at comcast.net
Thu Apr 24 00:24:27 EDT 2008


I think the best of all worlds would be a double-ovenized SC-cut OCXO
running at 5 MHz (lower mass). These OCXOs have the lowest phase noise and
best Allen variance short term stability (1-100 seconds) of any xtal or Rb.
Then have this OCXO disciplined by the GPS, with an ephemeris of variations
constantly collected, statically averaged over a long period (at least 1
month), and the calculated average used to adjust the OCXO frequency.

Tom Duckworth

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of John Miles
Sent: Wednesday, April 23, 2008 8:02 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Disciplining Rubidium

Adding to Tom's worthy list:

11) Short-term phase noise; the GPS-Rb sources don't seem to be as clean as
the better GPS-OCXO packages.

-- john, KE5FX

> > More precisely, if I had two black boxes, one containing
> > a GPS-Rb-XTAL setup and another containing GPS-XTAL,
> > what measurement would you make from outside the boxes
> > to distinguish from one another?
> Ah, clever question. Here's ten ways to distinguish them...

time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to
and follow the instructions there.

More information about the time-nuts mailing list