On Dienstag, 3. März 2020 09:25:13 CET Dana Whitlow wrote: > Matthias, > > You said that the LPRO has a pulling range of 4 PPM. Really? I > would think that 4PPB would be much more likely for a Rb.
Yes, sorry, typing mistake. The user guide says "more then +/- 1.5E-9", I found it more in the range +/- 2E-9". It's 4ppb, not 4ppm. BR, Matthias > > Dana > > > On Mon, Mar 2, 2020 at 3:21 PM Matthias Welwarsky <[email protected]> > > wrote: > > On Montag, 2. März 2020 18:32:44 CET Skip Withrow wrote: > > [...] > > > > > The Thunderbolt DAC steps in 10uV steps IIRC. And it steps its DAC > > > voltage every second. With GPS signals jumping around you can still > > > (will) end up with poorer short term performance than if the Rb was > > > left to its own devices. Hint, let the Thunderbolt do its thing with > > > the Rb, but use Lady Heather and disable disciplining when making > > > measurements/comparisons. > > > > The LPRO has a pulling range of just 4ppm at the external C-Field input > > (0-5V > > swing). 10µV steps over 6V should be, like 19 bits or so? That should give > > at > > least 7e-15 resolution for the DAC. > > > > With a reasonably stable PPS from a timing receiver, just looking at the > > DAC > > movements, it should not be a problem to have a MDEV of 1e-14'ish for > > tau=1s. > > The LPRO itself probably has a MDEV of somewhere between 1e-11 to 1e-10 at > > tau=1s, so the GPSDO is not going to cause a lot of disturbance. Some, > > yes. > > The undisturbed Rb will always be better short-term than the disciplined > > one. > > But not an awful lot. > > > > BR, > > Matthias > > > > > Regards, > > > Skip Withrow > > > > > > _______________________________________________ > > > time-nuts mailing list -- [email protected] > > > To unsubscribe, go to > > > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and > > > > follow > > > > > the instructions there. > > > > _______________________________________________ > > time-nuts mailing list -- [email protected] > > To unsubscribe, go to > > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow > the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
