Re: [time-nuts] Z3805 incident
Sorry, Ulli, if I'm not quite with it, today... Which one is the bad guy now, the oven or the RX? We can't decide that, can we? IMHO does neither the EFC nor the PPS TI response tell us, whether the RX or the Crystal caused this peak, what we see is just the difference time between them. Or does the time constant reveal more? Thank you Volker Am 29.11.2012 08:28, schrieb Ulrich Bangert: Volker, please note that much of the clear text in the status information is generated by Z38XX itself to make it easier to read. 2012-11-28 10:01:40: The last Smartclock Status is undefined 2012-11-28 10:01:40: Starting with status LOCK for example means that Z38XX is unaware of the receiver status and assumes that the status is locked. 73s de Ulli, DF6JB -Ursprüngliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von Volker Esper Gesendet: Mittwoch, 28. November 2012 22:24 An: Discussion of precise time and frequency measurement Betreff: [time-nuts] Z3805 incident When looking at the PPS TI vs. time curve today I felt kind of appalled - a big incident peak (not an outlier) on the curve! See picture. What happened to my Z3805? Any idea? No entry in the error log, the staus log says 2012-11-28 10:01:30: The Smartclock Status has changed to LOC 2012-11-28 10:01:40: The last Smartclock Status is undefined 2012-11-28 10:01:40: Starting with status LOCK Thanks Volker ___ 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.
Re: [time-nuts] Z3805 incident
On 29 Nov, 2012, at 02:32 , Charles P. Steinmetz charles_steinm...@lavabit.com wrote: This is a classic crystal jump. The crystal changed its frequency magically from one second to the next and the software compensated for it Here is another example of a 3805 having a bad moment. For just about two minutes, it reported a phase jump of nearly 3 uS and then immediately fell back nearly to its previous baseline, settling to the baseline in about an hour and not requiring any longer-term change of the EFC voltage. This does not look like a typical crystal frequency shift to me, but I cannot rule that out. It looks more like what I'd expect to see if I set the cable delay to 3 uS for 2 minutes, then back to 0. I think I would be more likely to call this one, where the crystal jumps to another frequency for a while and then jumps back to about what it was, a classic crystal jump. I've seen this before, though not as large as the change you show. I hear these raise hell when they try to use PTP to transmit telecom-quality timing over asynchronous ethernet because it is hard to run a PTP control loop tight enough (i.e. at a high enough data rate) to correct that before it does damage. I think the other problem, with the crystal jumping to another frequency and apparently staying there (I'm assuming it hasn't jumped back), could have a broader range of causes. Dennis Ferguson ___ 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.
Re: [time-nuts] Z3805 incident
...and I should see the loop time constant in the ADEV, too - if that is the case, the time constant should be about 2000 s, shouldn't it? (see picture) Volker Am 29.11.2012 05:35, schrieb Said Jackson: Volker, This is a classic crystal jump. The crystal changed its frequency magically from one second to the next and the software compensated for it You can nicely see the time constant of the loop.. Bye Said Sent From iPhone On Nov 28, 2012, at 13:24, Volker Esperail...@t-online.de wrote: When looking at the PPS TI vs. time curve today I felt kind of appalled - a big incident peak (not an outlier) on the curve! See picture. What happened to my Z3805? Any idea? No entry in the error log, the staus log says 2012-11-28 10:01:30: The Smartclock Status has changed to LOC 2012-11-28 10:01:40: The last Smartclock Status is undefined 2012-11-28 10:01:40: Starting with status LOCK Thanks Volker DF9PL_GPSDO_2_20121128_2108_PPS-TI_b.jpg ___ 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. attachment: DF9PL_GPSDO_1_20121128_2109_sigma(tau)_b.jpg___ 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.
Re: [time-nuts] Z3805 incident
HI Some simple empirical data: 1) Jumps tend to get further apart as the oscillator ages. 2) AT's have larger jumps than SC's. 3) A typical SC jump is below 1x10^-9 4) It's not a lot of things (spurs, drive, temperature, load,stress, micro-fractures, plating defects) if you need to explain all cases = they don't explain all events 5) It can be a lot of things (spurs, drive, temperature, load, stress, micro-fractures, plating defects) in some cases = they do explain some events The first published data I have seen on jumps is in a Fairchild Semiconductor App note from the late 60's / early 70's. They built a JFET based oscillator and it jumped…. Bob On Nov 29, 2012, at 7:30 PM, Volker Esper ail...@t-online.de wrote: ...imho it has indeed jumped back, see the picture of 1643 GMT today. You recognize the peak down yesterday at about 1900 GMT, then a smaller peak up at about 2300 GMT and - after having a troubled night - again a peak up. The EFC voltage now is nearly the same as prior to the impact series. I suppose it's actually a crystal jump. In 1997 HP wrote in it's AN 200-2 (Fundamentals of Quartz Oscillators): ...Crystals having unwanted signals could also shift from one resonate point to another producing a frequency jump which would be an undesirable effect. IEEE has some experience with that phenomenon, too. An article from 1996 can be found in their Digital Library http://ieeexplore.ieee.org/xpl/login.jsp?tp=arnumber=559877url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel3%2F4090%2F12100%2F00559877.pdf%3Farnumber%3D559877 wich deals with that issue: In this paper recently classified intermittent and discrete frequency jump phenomena are briefly reviewed and currently not well understood abrupt frequency jump phenomena are analysed and discussed in detail. John R. Vig writes in his Quartz Crystal Resonators and Oscillators For Frequency Control and Timing Applications - A Tutorial (2004): It is the changes in the stresses, and the changes produced by the stresses that cause frequency instabilities. There exists evidence that, on a microscopic level, stress relief is not a continuous process. It can occur in bursts that can, possibly, contribute to noise and frequency jumps. Numerous articles discuss the effects of contamination and failures of the crystal clamp that obviously contribute to the phenomenon. Though very interesting stuff, that all sounds kind of academical to me. Now I know it could be possible, that my GPSDO suffers from that cause. However, since I don't know if or when or how often the effect recurs, I am the one, who has broken nights now... I'll keep a jealous watch over the diagrams... Volker Am 30.11.2012 00:14, schrieb Dennis Ferguson: On 29 Nov, 2012, at 02:32 , Charles P. Steinmetzcharles_steinm...@lavabit.com wrote: This is a classic crystal jump. The crystal changed its frequency magically from one second to the next and the software compensated for it Here is another example of a 3805 having a bad moment. For just about two minutes, it reported a phase jump of nearly 3 uS and then immediately fell back nearly to its previous baseline, settling to the baseline in about an hour and not requiring any longer-term change of the EFC voltage. This does not look like a typical crystal frequency shift to me, but I cannot rule that out. It looks more like what I'd expect to see if I set the cable delay to 3 uS for 2 minutes, then back to 0. I think I would be more likely to call this one, where the crystal jumps to another frequency for a while and then jumps back to about what it was, a classic crystal jump. I've seen this before, though not as large as the change you show. I hear these raise hell when they try to use PTP to transmit telecom-quality timing over asynchronous ethernet because it is hard to run a PTP control loop tight enough (i.e. at a high enough data rate) to correct that before it does damage. I think the other problem, with the crystal jumping to another frequency and apparently staying there (I'm assuming it hasn't jumped back), could have a broader range of causes. Dennis Ferguson ___ 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. DF9PL_GPSDO_2_20121129_2137_PPS-TI.jpgDF9PL_GPSDO_2_20121129_1643_PPS-TI.jpg___ 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.
[time-nuts] Z3805 incident
When looking at the PPS TI vs. time curve today I felt kind of appalled - a big incident peak (not an outlier) on the curve! See picture. What happened to my Z3805? Any idea? No entry in the error log, the staus log says 2012-11-28 10:01:30: The Smartclock Status has changed to LOC 2012-11-28 10:01:40: The last Smartclock Status is undefined 2012-11-28 10:01:40: Starting with status LOCK Thanks Volker attachment: DF9PL_GPSDO_2_20121128_2108_PPS-TI_b.jpg___ 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.
Re: [time-nuts] Z3805 incident
The reference is still the Rb? Then how you can tell which of the two is doing that... On Wed, Nov 28, 2012 at 10:24 PM, Volker Esper ail...@t-online.de wrote: When looking at the PPS TI vs. time curve today I felt kind of appalled - a big incident peak (not an outlier) on the curve! See picture. What happened to my Z3805? Any idea? No entry in the error log, the staus log says 2012-11-28 10:01:30: The Smartclock Status has changed to LOC 2012-11-28 10:01:40: The last Smartclock Status is undefined 2012-11-28 10:01:40: Starting with status LOCK Thanks Volker ___ 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.
Re: [time-nuts] Z3805 incident
Ops, I missed the EFC value... On Wed, Nov 28, 2012 at 10:43 PM, Azelio Boriani azelio.bori...@screen.itwrote: The reference is still the Rb? Then how you can tell which of the two is doing that... On Wed, Nov 28, 2012 at 10:24 PM, Volker Esper ail...@t-online.de wrote: When looking at the PPS TI vs. time curve today I felt kind of appalled - a big incident peak (not an outlier) on the curve! See picture. What happened to my Z3805? Any idea? No entry in the error log, the staus log says 2012-11-28 10:01:30: The Smartclock Status has changed to LOC 2012-11-28 10:01:40: The last Smartclock Status is undefined 2012-11-28 10:01:40: Starting with status LOCK Thanks Volker ___ 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.
Re: [time-nuts] Z3805 incident
Not Rb but OCXO vs GPS... Am 28.11.2012 22:47, schrieb Azelio Boriani: Ops, I missed the EFC value... On Wed, Nov 28, 2012 at 10:43 PM, Azelio Boriani azelio.bori...@screen.itwrote: The reference is still the Rb? Then how you can tell which of the two is doing that... On Wed, Nov 28, 2012 at 10:24 PM, Volker Esperail...@t-online.de wrote: When looking at the PPS TI vs. time curve today I felt kind of appalled - a big incident peak (not an outlier) on the curve! See picture. What happened to my Z3805? Any idea? No entry in the error log, the staus log says 2012-11-28 10:01:30: The Smartclock Status has changed to LOC 2012-11-28 10:01:40: The last Smartclock Status is undefined 2012-11-28 10:01:40: Starting with status LOCK Thanks Volker ___ 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. ___ 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.
Re: [time-nuts] Z3805 incident
Volker, please note that much of the clear text in the status information is generated by Z38XX itself to make it easier to read. 2012-11-28 10:01:40: The last Smartclock Status is undefined 2012-11-28 10:01:40: Starting with status LOCK for example means that Z38XX is unaware of the receiver status and assumes that the status is locked. 73s de Ulli, DF6JB -Ursprüngliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von Volker Esper Gesendet: Mittwoch, 28. November 2012 22:24 An: Discussion of precise time and frequency measurement Betreff: [time-nuts] Z3805 incident When looking at the PPS TI vs. time curve today I felt kind of appalled - a big incident peak (not an outlier) on the curve! See picture. What happened to my Z3805? Any idea? No entry in the error log, the staus log says 2012-11-28 10:01:30: The Smartclock Status has changed to LOC 2012-11-28 10:01:40: The last Smartclock Status is undefined 2012-11-28 10:01:40: Starting with status LOCK Thanks Volker ___ 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.
