Hi Well an un-stated assumption of mine was that they all came from the same measurement system and that it had the same floor under all circumstances….
Bob > On Aug 7, 2015, at 5:21 PM, John Miles <j...@miles.io> wrote: > >> Hi >> >> If that data is correct, then the 10811 you have is defective. >> Bob > > Well... some of the data is reasonable for a scenario where a counter is > being used to measure OCXOs. > > Looking at the ADEV plot, I'd say the blue trace (HP105B vs 5065A) is the > most questionable one if it came from a standalone TIC or frequency counter, > because 7E-12 @ t=1s isn't achievable with most counters under most > circumstances. A Wavecrest box can measure at that level if it's set up > _perfectly_ to take bursts of 100+ wrap-free averages within a small fraction > of the t0 interval. It might also be doable with an HP 5370A/B under similar > conditions, but I'd have less confidence that the averaging isn't distorting > the measurement. So while It looks like a valid measurement of an OCXO with > some minor crosstalk or other external interference, that may just be a > coincidence. > > Luciano, how was the blue trace taken? Is this from your DMTD project? If > so, it's looking promising. > > The green and magenta traces are definitely in the right ballpark for > measurements on a 5370-class counter. At 3E-11 @ t=12s the magenta trace is > optimistic but not outrageously so, while the green trace looks exactly like > I'd expect for a typical 10811 measured on a 5370. The observed noise is due > entirely to the counter until about t=200s. We see a glimpse of the 10811's > typical ADEV at about 250 seconds, just before either drift or ADEV > uncertainty causes the trace to turn upwards. A longer run would be needed > to distinguish between these two situations. > > -- john, KE5FX > Miles Design LLC > > > _______________________________________________ > 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.
