[time-nuts] Z3805 initial behaviour after power up

Ulrich Bangert df6jb at ulrich-bangert.de
Wed Jun 17 07:33:19 EDT 2009


Steve,

> I must have lost the plot here but I thought that was only 
> for HPIB data.

By far not! PLOTTER does a lot to everything than can be pressed into ASCII
data column files.

> How are you collecting the data?

That has been done with a quick and dirty script for my EZGPIB utility
(which handles serial communication and some other goodies as well). I have
just included this script as "Z3805.488" to the examples.

Don't accuse me that I did not have warned you: PLOTTER is written in the
P-language while EZGPIB (which is written in the P-language itself) executes
scripts in the P-language, P-square if you like. Better get on rubber gloves
before you touch anything of it, hi.

73s Ulrich, DF6JB  


> -----Ursprungliche Nachricht-----
> Von: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Steve Rooke
> Gesendet: Mittwoch, 17. Juni 2009 11:29
> An: Discussion of precise time and frequency measurement
> Betreff: Re: [time-nuts] Z3805 initial behaviour after power up
> 
> 
> Ulrich,
> 
> I must have lost the plot here but I thought that was only 
> for HPIB data. How are you collecting the data?
> 
> 73,
> Steve
> 
> 2009/6/17 Ulrich Bangert <df6jb at ulrich-bangert.de>:
> > Steve,
> >
> > my PLOTTER utility. I thought you did already try it out?
> >
> > 73s Ulrich, DF6JB
> >
> >> -----Ursprungliche Nachricht-----
> >> Von: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at 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 <df6jb at 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 at febo.com
> >> > To unsubscribe, go to 
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> >> > 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 at febo.com
> >> To unsubscribe, go to 
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> >> and follow the instructions there.
> >
> >
> > _______________________________________________
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> >
> 
> 
> 
> -- 
> 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 at febo.com
> To unsubscribe, go to 
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