Hal, > How close could you get if you brought two of them together, compared phase, > drove them to the site for a nights work, drove them back to the same > location and compared the phase again.
That's essentially asking what the ADEV (or, TDEV) is for tau 1 day. Rb isn't near good enough. Neither is Cs, for that matter. See www.leapsecond.com/tmp/5071a-12-run8-5d-10d.gif for a plot of a bunch of 5071A Cs clocks. They are compared together for 5 days to determine their relative phase and frequency offsets and then go on a 5-day trip. You can see how the phase drifts as random walk does its thing. It's way more than 500 ps per day. That's why the OP cannot use free-running clocks. He needs some method to actively keep them in tight phase lock or passively compare them to within 500 ps in order to adjust the timestamps in post-facto. /tvb ----- Original Message ----- From: "Hal Murray" <[email protected]> To: "Tom Van Baak" <[email protected]>; "Discussion of precise time and frequency measurement" <[email protected]> Cc: <[email protected]> Sent: Wednesday, May 04, 2016 10:30 AM Subject: Re: [time-nuts] Fw: Optical transfer of time and frequency > > [email protected] said: >> Any of these methods is going to be a challenge, given their 500 ps >> requirement and their $2k budget. > > How stable are surplus rubidium oscillators? > > How close could you get if you brought two of them together, compared phase, > drove them to the site for a nights work, drove them back to the same > location and compared the phase again. > > > -- > These are my opinions. I hate spam. > > > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
