[time-nuts] Problems using digital TV signals as a time source
A little while back there was a discussion about some of the issues using the PSIP data from digital TV broadcasts as a time source... it's not a good idea. Here is some data of why not: http://home.earthlink.net/~schultdw/atsc/tdata/index.html And when daylight savings time gets thrown into the mix: http://home.earthlink.net/~schultdw/atsc/dst_data/index.html ___ 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] CSAC change in temperature, max is now 40C
My understanding is that 1000's of these are deployed on commercial ocean bottom seismographs (Co. name not important) and per my last conversation with them, that they had identified long term failure's on the CSAC. They also indicated that they could detect when failure was imminent, and that microsemi was implementing a 'fix'. Could be unrelated, but this might be the fix. Brent On Mon, Feb 9, 2015 at 7:06 PM, Jim Lux wrote: > The latest rev of the CSAC data sheet (rev H) shows the max non-operating > temperature to be 40C.. > and operating from -10 to +35C > > that's a substantial difference from the former version of the sheet which > presumably had the temperatures from the summary page: > The Quantum SA.45s Chip Scale Atomic Clock (CSAC) is available in the > following versions: > > Option 001, operates from -10 °C to +70 °C with an output frequency of > 10 MHz, ADEV = 2.5E-10 (tau = 1 sec) > Option 002, operates from -40 °C to +85 °C with an output frequency of > 10 MHz , ADEV = 2.5E-10 (tau=1 sec) > Option 003, operates from -10 °C to +70 °C with an output frequency of > 16.384 MHz, ADEV = 2.5E-10 (tau = 1 sec) > Option 004, operates from -10 °C to +70 °C with an output frequency of > 10.24 MHz, ADEV = 2.5E-10 (tau = 1 sec) > Option 006, operates from -10 °C to +70 °C with an output frequency of > 5 MHz, ADEV = 2.5E-10 (tau = 1 sec) > > > Rev H appears to be 121014 (12 October or 10 Dec 2014, I'd guess) > http://www.microsemi.com/document-portal/doc_download/ > 133305-quantum-sa-45s-csac > > > I wonder what happened? Is it a typo? are they seeing high temperature > failures? > > As a practical matter, a max operating temp of 35 and storage/ship of 40 > would make me nervous about shipping one in midsummer in California.. > That brown UPS truck gets pretty toasty warm, and 40C is easily achieved, > although fairly unusual for "in the shade air temp" > > And, of course, makes it useless for outdoor applications of any kind. > ___ > 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] CSAC change in temperature, max is now 40C
The latest rev of the CSAC data sheet (rev H) shows the max non-operating temperature to be 40C.. and operating from -10 to +35C that's a substantial difference from the former version of the sheet which presumably had the temperatures from the summary page: The Quantum SA.45s Chip Scale Atomic Clock (CSAC) is available in the following versions: Option 001, operates from -10 °C to +70 °C with an output frequency of 10 MHz, ADEV = 2.5E-10 (tau = 1 sec) Option 002, operates from -40 °C to +85 °C with an output frequency of 10 MHz , ADEV = 2.5E-10 (tau=1 sec) Option 003, operates from -10 °C to +70 °C with an output frequency of 16.384 MHz, ADEV = 2.5E-10 (tau = 1 sec) Option 004, operates from -10 °C to +70 °C with an output frequency of 10.24 MHz, ADEV = 2.5E-10 (tau = 1 sec) Option 006, operates from -10 °C to +70 °C with an output frequency of 5 MHz, ADEV = 2.5E-10 (tau = 1 sec) Rev H appears to be 121014 (12 October or 10 Dec 2014, I'd guess) http://www.microsemi.com/document-portal/doc_download/133305-quantum-sa-45s-csac I wonder what happened? Is it a typo? are they seeing high temperature failures? As a practical matter, a max operating temp of 35 and storage/ship of 40 would make me nervous about shipping one in midsummer in California.. That brown UPS truck gets pretty toasty warm, and 40C is easily achieved, although fairly unusual for "in the shade air temp" And, of course, makes it useless for outdoor applications of any kind. ___ 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] MSF Scheduled Maintenance Periods
In message <20150209121219.gy21...@belle.intranet.vanheusden.com>, folkert writ es: >> MSF Scheduled Maintenance Periods >> >> The MSF 60 kHz standard-frequency and time signal, broadcast by Babcock on >> behalf of NPL, is occasionally taken off-air to allow maintenance work on >> the masts and antennas at Anthorn Radio Station to be carried out in safety. >> This means that your radio-controlled clock will not be picking up the MSF >> signal, so may not be working correctly. > >Could it be that they changed something with their setup? The most likely explanation is a switch-mode power-supply in the local environment. 60kHz is a very popular choice of switching frequency. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ 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] MSF Scheduled Maintenance Periods
Folkert, As far as I know the transmitted signal has not changed and is its normal strength with me. Have you thought that you may be experiencing some form of interference to the signal? If you can monitor the signal on a receiver, maybe on a long wave broadcast receiver, you may find that there are many loud noises heard from wall mounted power units, computer supplies etc. In particular the use of computer networking equipment that uses the household electricity supply cables, such as homeplug, can be very destructive. Can you check if you have connected some new equipment such as a laptop, telephone charger etc and as a test disconnect them all and see if the receiver then works OK. Best of luck in finding the problem Peter On 09/02/2015 12:12, folkert wrote: MSF Scheduled Maintenance Periods The MSF 60 kHz standard-frequency and time signal, broadcast by Babcock on behalf of NPL, is occasionally taken off-air to allow maintenance work on the masts and antennas at Anthorn Radio Station to be carried out in safety. This means that your radio-controlled clock will not be picking up the MSF signal, so may not be working correctly. Could it be that they changed something with their setup? A couple of years back I could receive MSF fine (Gouda, the Netherlands) but this year (reconnected the radio in January) no bit comes in at all. The led on the radio also flickers dramatically, not once per second. Folkert van Heusden ___ 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] MSF Scheduled Maintenance Periods
Could it be that they changed something with their setup? A couple of years back I could receive MSF fine (Gouda, the Netherlands) but this year (reconnected the radio in January) no bit comes in at all. The led on the radio also flickers dramatically, not once per second. Folkert van Heusden === Folkert, I'm not aware of any significant changes. Could it be that you have more interference at 60 kHz than two years ago? Cheers, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ 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] Wavecres SIA-3000 and DTS-2070 schematics (was: T.I. questions)
I have two DTS2070s. The only manual I can find now is one for the DTS-2079. No schematics, but, a whole lot of other info. Can email it to you if you would like. Regards - Mike Mike B. Feher, EOZ Inc. 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 office 908-902-3831 cell -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Attila Kinali Sent: Monday, February 09, 2015 5:28 AM To: Discussion of precise time and frequency measurement Subject: [time-nuts] Wavecres SIA-3000 and DTS-2070 schematics (was: T.I. questions) On Fri, 06 Feb 2015 20:55:56 +0100 Magnus Danielson wrote: > The Wavecres SIA-3000 has a single-shot resolution of 200 fs, but the > trigger jitter. Later models only went to 300 fs as far as I know. The > DTS-2070C has a resolution of 800 fs. Hmm... does anyone have the schematics (or any other description of the inner working) of those two? My google skills fail me. Attila Kinali ___ 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] D term (was no subject)
Many thanks for the link, Attila. One of the authors of Volume 25 was Nichols of "Ziegler-Nichols tuning" fame (q.v.) Bill Hawkins -Original Message- From: Attila Kinali Sent: Monday, February 09, 2015 4:14 AM And here the link to the pdf's in case anyone is looking: https://www.jlab.org/ir/MITSeries.html ___ 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] MSF Scheduled Maintenance Periods
> MSF Scheduled Maintenance Periods > > The MSF 60 kHz standard-frequency and time signal, broadcast by Babcock on > behalf of NPL, is occasionally taken off-air to allow maintenance work on > the masts and antennas at Anthorn Radio Station to be carried out in safety. > This means that your radio-controlled clock will not be picking up the MSF > signal, so may not be working correctly. Could it be that they changed something with their setup? A couple of years back I could receive MSF fine (Gouda, the Netherlands) but this year (reconnected the radio in January) no bit comes in at all. The led on the radio also flickers dramatically, not once per second. Folkert van Heusden -- MultiTail är ett flexibel redskap för att följa en eller flera logfiler, utföra kommandon, filtrera, färglägga, sammanfoga, o.s.v... -- Phone: +31-6-41278122, PGP-key: 1F28D8AE, www.vanheusden.com ___ 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] Good references on holdover?
This is a great list. Thanks everyone! Much of the material relates to cases where good holdover needs to be maintained for several hours, but there's a lot of insight to be gained from the reading, and I am sure those techniques will come in handy for other projects. Thanks again! Javier On Fri, Feb 6, 2015 at 2:58 PM, Attila Kinali wrote: > On Fri, 6 Feb 2015 10:21:08 +0100 > Javier Serrano wrote: > >> We would like to start working on holdover performance for White >> Rabbit [1]. This is a new domain for us. Our main use case is a WR >> switch losing its reference because someone disconnects a fiber. We >> can have redundancy, but it will take some time for a switch to change >> over to another reference. During this time, the oscillator in that >> switch will be free-running. We want to minimize the phase drift >> during that interval, which we think should be a couple of seconds >> maximum. We have never worked on holdover, and I am wondering if we >> can do something smarter than the obvious feeding of some constant >> voltage to the VCXO, based on averaging during the locked state. Does >> anybody know of any good references on holdover? > > I think you are looking for something like [1]. I think [2] could be also > of help, although it's not as good as the Nicholls paper. Zhou's paper [3] > seems to be very similar to what Nicholls did (i have not fully read it yet). > > HTH > > Attila Kinali > > > > [1] "Adaptive OXCO Drift Correction Algorithm", by Nicholls and Carlton, 2004 > http://dx.doi.org/10.1109/FREQ.2004.1418510 > > [2] "A Frequency Model for OCXO for Holdover Mode of DP-PLL", > by Hwang, Shin, Han, Kim, 2000 > http://dx.doi.org/10.1109/SICE.2000.889649 > > [3] "Adaptive Correction Method for an OCXO and Investagion of Analytical > Cummulative Time Eror Upperbound", by Zhou, Kunz, Schwartz, 2011 > http://www.sce.carleton.ca/faculty/schwartz/abstracts/HuiPaperschwartz.pdf > > -- > It is upon moral qualities that a society is ultimately founded. All > the prosperity and technological sophistication in the world is of no > use without that foundation. > -- Miss Matheson, The Diamond Age, Neil Stephenson > ___ > 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] Wavecres SIA-3000 and DTS-2070 schematics
Attila, On 02/09/2015 11:28 AM, Attila Kinali wrote: On Fri, 06 Feb 2015 20:55:56 +0100 Magnus Danielson wrote: The Wavecres SIA-3000 has a single-shot resolution of 200 fs, but the trigger jitter. Later models only went to 300 fs as far as I know. The DTS-2070C has a resolution of 800 fs. Hmm... does anyone have the schematics (or any other description of the inner working) of those two? My google skills fail me. I've made sure to dump a lot of documentations on Didiers site. There is a set of interesting patents to be read. Essentially a 100 MHz coarse clock and Time-to-voltage converters followed by ADCs as the basic approach, nothing new, they just went further than many others. 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] Wavecres SIA-3000 and DTS-2070 schematics (was: T.I. questions)
On Fri, 06 Feb 2015 20:55:56 +0100 Magnus Danielson wrote: > The Wavecres SIA-3000 has a single-shot resolution of 200 fs, but the > trigger jitter. Later models only went to 300 fs as far as I know. The > DTS-2070C has a resolution of 800 fs. Hmm... does anyone have the schematics (or any other description of the inner working) of those two? My google skills fail me. Attila Kinali -- It is upon moral qualities that a society is ultimately founded. All the prosperity and technological sophistication in the world is of no use without that foundation. -- Miss Matheson, The Diamond Age, Neil Stephenson ___ 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] D term (was no subject)
On Fri, 06 Feb 2015 21:20:39 + "Poul-Henning Kamp" wrote: > >If anyone wants to dive into control theory I recommend reading the > >book "Feedback control of dynamic systems" by Franklin, Powell and > >Emami-Naeini. > > And if you are more of a historical bent, the MIT Radiation Lab > series is the motherlode. And here the link to the pdf's in case anyone is looking: https://www.jlab.org/ir/MITSeries.html Attila Kinali -- It is upon moral qualities that a society is ultimately founded. All the prosperity and technological sophistication in the world is of no use without that foundation. -- Miss Matheson, The Diamond Age, Neil Stephenson ___ 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.
