Hi Magnus; Very Nice Best Wishes; Thomas Knox
> Date: Thu, 2 Aug 2012 18:36:31 +0200 > From: mag...@rubidium.dyndns.org > To: time-nuts@febo.com > Subject: [time-nuts] FTS1200, OSA8600, OSA8601 phase noise and ADEV measures > > Fellow time-nuts, > > I have borrowed Björn's FTS1200 and OSA8600 and that complements my own > OSA8600 and OSA8601. > > I use a HP5087A and one of the OSA8600 as references, such that I can > cross-correlate out the reference oscillators. I'm still not quite > satisfied just yet, so I may need to work some more to perfect this > technique. > > http://rubidium.dyndns.org/~magnus/time/timelab/FTS1200_OSA8600_OSA8601_20120802_1.png > > Here you see the phase-noise of the four oscillators. > It is distinct how the white noise floor of the FTS1200 is around -141 > dBc/Hz when the OSA8600s reach for -155 to -156 dBc/Hz. > > The spurs on the FTS1200 may trace back to the fact that the FTS1200 is > -1.5 Hz of the references, but I like Johns comments on that. > > You can see that the older OSA8601 has better 1/f noise and that Björn's > OSA8600 SN711 has higher 1/f^3 noise than any of the other three which > seems comparable. The OSA8600 SN711 and SN817 has comparable 1/f noise. > > http://rubidium.dyndns.org/~magnus/time/timelab/FTS1200_OSA8600_OSA8601_20120802_2.png > > The ADEV plot of the oscillators. > The noise on the FTS1200 dominates, it's inital response, but it is more > clearly seen that the flat section is better and the OSAs. > > http://rubidium.dyndns.org/~magnus/time/timelab/FTS1200_OSA8600_OSA8601_20120802_3.png > The Hadamard Deviation plot of the oscillators. > The linear drift of the FTS1200 and OSA8601 is seen. > > http://rubidium.dyndns.org/~magnus/time/timelab/FTS1200_OSA8600_OSA8601_20120802_4.png > > The phase difference plot of the oscillators: > The linear drift noticed from the ADEV plot and mostly removed in the > Hadamard plot is seen more clearly in the phase plot as quadratic > phase-shifts, a slot tendency on the other oscillatos can also be seen. > > http://rubidium.dyndns.org/~magnus/time/timelab/FTS1200_OSA8600_OSA8601_20120802_5.png > > The Frequency difference of the oscillators. > The noise of the FTS1200 is visible. I haven't looked into it. > > As you may have noted, the measurement length varies, I haven't looked > into it. > > My OSAs has been heated for a fairly long time, even if they had a short > dip of voltage. Björns FTS1200 and OSA has been heated for almost 2 > weeks now. > > Measurement files: > http://rubidium.dyndns.org/~magnus/time/timelab/FTS1200_HP5065A_OSA86000_20120802_1.tim > http://rubidium.dyndns.org/~magnus/time/timelab/OSA8600SN711_HP5065A_OSA86000_20120802_1.tim > http://rubidium.dyndns.org/~magnus/time/timelab/OSA8600SN817_HP5065A_OSA86000_20120802_1.tim > http://rubidium.dyndns.org/~magnus/time/timelab/OSA8601SN1314_HP5065A_OSA86000_20120802_1.tim > > Comments welcome. I will spend some more quality time on this now that > I've made a first stab at it. > > Got to locate a cable so I can toss a well-heated 10811A into the battle. > > Cheers, > Magnus > > _______________________________________________ > 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.