These are less stable than a rubidium eg tau=10e-11@1000s and monthly ageing of 9e-10. The price of these has gone up too- they're now about US5000.
Cheers Michael On Wed, 22 Mar 2017 at 7:03 am, Scott McGrath <scmcgr...@gmail.com> wrote: > Or perhaps use the Symmetricom CSAC ... > > Relatively expensive but might work > > > On Mar 21, 2017, at 8:08 AM, Attila Kinali <att...@kinali.ch> wrote: > > > > On Tue, 21 Mar 2017 13:38:51 +1100 > > Hugh Blemings <h...@blemings.org> wrote: > > > >> This got me to wondering if a Rubidium based standard might do the trick > >> - the Efratom SLCR-101s seem readily available for ~USD$200 mark. > > > > As TvB wrote, a single one will not do the trick. You will need > > a stability 1e-14 @1d. IIRC most Rb standards floor out at 1e-12 to 1e-13 > > somewhere between 1k and 100k seconds. Even the Super-5065 has a floor > > of about 3-4e-14 (unless our friends here improved on this already). > > > > There will be a few things that you will need to do, if you want to go > > with Rubidiums: > > 1) Stabilize or compensate for environmental effects (temperature, air > pressure) > > 2) Build ensembles of Rb clocks. > > > > The former is to prevent the ADEV from "turning upwards" again and > > keep the Rb's as stable as possible as long as possible. I have no > > experience how much this helps, but I suspect, with the correct modeling > > that you could get the ADEV to be flat up to a day, maybe even two. > > You will have to include aging and drift of the cell itself in the model. > > This also means that you will have your Rbs running for a few > weeks/months > > prior to any measurement so that the aging settles down a bit. > > > > The ensemble is to get the ADEV down. Averaging of clocks with the same > > noise decreases the ADEV by the square root of the number of clocks used. > > If you are close to the ADEV you need, the averaging will help you > getting > > it further down. Unfortunately, getting from 1e-13 down to 1e-14 is > > impractical as you'd need 100 clocks to average over.... But a factor > > of 2 to 3 should be possible. > > > > > > Alternatively, you can ask Oscilloquartz whether they let you borrow > > two of their new OSA3300 for a publicity stunt :-) > > > > Attila Kinali > > -- > > It is upon moral qualities that a society is ultimately founded. All > > the prosperity and technological sophistication in the world is of no > > use without that foundation. > > -- Miss Matheson, The Diamond Age, Neil Stephenson > > _______________________________________________ > > time-nuts mailing list -- time-nuts@febo.com > > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
