Steve, my PLOTTER utility. I thought you did already try it out?
73s Ulrich, DF6JB > -----Ursprungliche Nachricht----- > Von: time-nuts-boun...@febo.com > [mailto:time-nuts-boun...@febo.com] Im Auftrag von Steve Rooke > Gesendet: Mittwoch, 17. Juni 2009 11:03 > An: Discussion of precise time and frequency measurement > Betreff: Re: [time-nuts] Z3805 initial behaviour after power up > > > Ulrich, > > What are you using to produce the graph you attached please? > > 73, > Steve > > 2009/6/17 Ulrich Bangert <df...@ulrich-bangert.de>: > > Gents, > > > > yesterday I received the Z3805 that I had bought from > fluke.I on eBay > > and immediately put it to work. I recorded the EFC value as well as > > the PPS TI value over about 20 hours. Attached is the graph of thes > > two values. > > > > I interprete this graph in this way: > > > > 1) Immediately after power up (perhaps up to the end of the site > > survey) the regulation loop seems to work with a very short time > > constant which is able to bring the PPS TI close to zero > although the > > OCXO has lots of drift at this time. > > > > 2) Then the loop time constant seems to switch to a > significant higher > > value which does not keep up with the oscillator's drift, > which leads > > to the negative excursion of nearly 500 ns. > > > > 3) This seems to be too much for the regulation which leads to > > switching back to the short time constant and to bring the > PPS TI back > > to near zero and to return to the longer time constant again... > > > > 4) ...which lets the procedure repeat again and again: > Drift to -500 > > ns and pullback. > > > > 5) Note that I thought it was a kind of malfunction and send a > > :system:preset command to the device after the last negative PPS TI > > spike. The result was, that the total procedure repeated: About 2 > > hours of PPS TI close to zero then again the drift and pullback > > procedure however with a reduced drift rate. > > > > 6) After 11 hours or so the regulation loop's time constant > seems to > > match the OCXO's drift and a "real" lock of the pll seems to take > > place. (The lock led had been on already hours ago...) > > > > Since I do not have an manual for the Z3805: Can any of you Z3801 > > owners second this behaviour to be normal or would you > think that it > > is kind of special for the Z3805 or even a real malfunction (in the > > sense that the OCXO's drift is above the specs in the beginning)? > > > > Best regards > > Ulrich Bangert > > > > Ulrich Bangert > > www.ulrich-bangert.de > > Ortholzer Weg 1 > > 27243 Gross Ippener > > > > _______________________________________________ > > 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. > > > > > > -- > Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW > A man with one clock knows what time it is; > A man with two clocks is never quite sure. > > _______________________________________________ > 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.