Hi Past 100 seconds I have seen some FE's that look better than your LPRO plot and some FE's that look worse than your FE plots. Running in a +/- 2C room apparently is not the best way to operate them for good long tau performance.
Bob On Feb 8, 2012, at 9:36 PM, John Ackermann N8UR wrote: > As threatened, I've measured stability (out to a trustworthy 10K seconds) and > phase noise of the three popular telecom surplus Rb standards. I looked at > two units of the FE-5680, two units of the Efratom FRS, and one Datum LPRO. > (I have two more LPROs but don't have the mating connector on hand, and > didn't want to solder on all three.) > > The Cliff Notes version: > > * The units had similar short term stability from 1 to 100 seconds. > > * Above 100 seconds, the LPRO was the clear winner. The FE and FRS split, > with one of each being the worst two. > > * The FE-5680 phase noise loses big-time, both in noise floor and in the > quantity and amplitude of spurs. That DDS comes with a price. > > * The LPRO has the best phase noise floor and cleanest spectrum. > > Pretty plots and the underlying data are at > http://febo.com/pages/oscillators/rubes/ > > Important note: there's known to be a lot of variability among these units, > so my sample size of one or two each isn't a guarantee that your unit will > perform similarly. > > Next step is to do some longer-term stability measurements (out to 100K > seconds). You may see that data in a month or so. > > John > > _______________________________________________ > 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. _______________________________________________ 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.
