Re: [time-nuts] Paper about DCF77 performance
The clock-correction seemed a bit crude. I expected to find a PI-filter and a phase-accumulator to steer the 300 MHz to 37 MHz synthesis. Actually I do use a phase accumulator, in Fig. 26 it's inside the binary search block. The phase is accumulated during several seconds (longer for a noisy signal), then the binary search takes a decision in which direction to modify the clock correction. A standard binary search cannot recover from a wrong decision, therefore I use smaller steps which slowly converges to the final value. I assume that the clock correction could also be implemented with a classical PLL algorithm, it would be interesting to compare the performance. ___ 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] Paper about DCF77 performance
Hm. Is the paper now online or do I have to add it to my list of downloads at next university trip? Thanks - Henry Hal Murray schrieb: enge...@alumni.ethz.ch said: Building the best DCF77 receiver in the world :-) You have found the right place. :) -- ehydra.dyndns.info ___ 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] Paper about DCF77 performance
Here is the PDF version of my paper Performance Analysis and Receiver Architectures of DCF77 Radio-Controlled Clocks, which was published in the May 2012 issue of the IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control: http://goo.gl/sWjFX Have fun reading! I'd be glad to hear your feedback. --Daniel Engeler ___ 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] Paper about DCF77 performance
Hi Very interesting !!! Thanks very much for sharing it. Bob On Jun 17, 2012, at 5:18 PM, Daniel Engeler wrote: Here is the PDF version of my paper Performance Analysis and Receiver Architectures of DCF77 Radio-Controlled Clocks, which was published in the May 2012 issue of the IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control: http://goo.gl/sWjFX Have fun reading! I'd be glad to hear your feedback. --Daniel Engeler ___ 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] Paper about DCF77 performance
Hi Daniel, On 17/06/12 23:18, Daniel Engeler wrote: Here is the PDF version of my paper Performance Analysis and Receiver Architectures of DCF77 Radio-Controlled Clocks, which was published in the May 2012 issue of the IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control: http://goo.gl/sWjFX Have fun reading! I'd be glad to hear your feedback. First of all, many thanks for providing us with a link to the paper. Second, it's a good paper. It includes the inherent re-occurence of the signal which can be utilized. Good to see that. There is many layers of analysis, so one has to be patient when reading this to see it through. I was lacking a frequency/time stability measurement. It would have been good to know how good it is in time stability. TIE, ADEV and TDEV plots would have been welcome. Possibly even an MTIE. Also, I would have enjoyed a stability analysis for code and carrier phase separately. 24h plot of them shifting around with a GPS receiver as reference would suffice. The clock-correction seemed a bit crude. I expected to find a PI-filter and a phase-accumulator to steer the 300 MHz to 37 MHz synthesis. 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.
Re: [time-nuts] Paper about DCF77 performance
On 6/17/2012 5:18 PM, Daniel Engeler wrote: Here is the PDF version of my paper Performance Analysis and Receiver Architectures of DCF77 Radio-Controlled Clocks, which was published in the May 2012 issue of the IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control: http://goo.gl/sWjFX Have fun reading! I'd be glad to hear your feedback. --Daniel Engeler ___ 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. Thanks looking forward to reading it. Paul WB8TSL ___ 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] Paper about DCF77 performance
Hi Attila Thanks for the feedback. * you have a lot of simulation and measurments on BER vs SNR. For time-nutty needs that's not so relevant. An ADEV plot would be much more informative on the stability. * Also some data on the absolute timing variations vs time would be nice to have. Yes that would be nice, but my spare time is short for this and the dozens of other ideas I have. * Fig 23 shows a very complex board. Given that you only have a relatively simple analog stage and an FPGA i wonder what the rest is for. Just the usual power supply, DAC for debugging FPGA-internal signals, galvanically isolated USB for logging, debug headers. * You use an LTC1562 8th order bandpass: Do you compensate for it's frequency dependend delay and its variation? Or is negligible compared to the antenna? I do compensate for it. The remaining uncertainty is taken into account in the paper. * Do you do any temperature stabilization? No, but it would be a nice addition. * What kind of reference oscillator do you use? Abracon ASV-12.000MHZ-E-J-T, 20 ppm, 12 MHz * You talk about 20 to 50ppm variations for XO's, are you aware that these are maximum variation including production variabiltiy and that the stability of an good XO is usually in the range of a few ppm in office conditions (i've measured an XO in a PC that showed a long term (months) stability in the ppb range) I worked with worst-case ranges as if it were a mass production. * Why did you use an FPGA and not a simple DSP or one of the more powerfull uC's like an Cortex-M3/4? The algorigthms don't look computationally intensive. And that would simplify the development considerably. At that time, I wanted to have some fun with FPGAs. It would also work on a uC, which BTW already is my next project. Both ways have advantages, for example the clock correction algorithm is easier to implement on an FPGA, while the signal processing would be simpler on a uC. * Where did you do your measurements? In Schlieren? Yes. * What is the application you had in mind while developing this? Building the best DCF77 receiver in the world :-) Regards, Daniel ___ 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] Paper about DCF77 performance
Attila, An ADEV plot would be much more informative on the stability. I have found an old publication from former PTB researcher Dr. Peter Hetzel. This publication holds a diagram which (while not being exactly an ADEV plot) holds some interesting information on the topic: It shows the STANDARD DEVIATION of timing measurements made on DCF77's signal abt. 273 km away from the transmitter location as a function of the averaging time of the measurements. So no ADEV but coming close... The diagram starts at abt. 8E-8 std dev for 1 s avaraging time and is basically a straight line with a slope of abt. -0.8. that extends to 7E-14 for averaging times of 100 days. I list a few values: 8E-8@ 1 s 1E-9 @ 10 s 2E-10 @ 100 s 5E-11 @ 1000 s 2E-12 @ 1 d 3E-13 @ 10 d 7E-14 @ 100 d The diagram has no log sub scale so the readings are my estimate. The diagram hold a lot of individual points between 10 and 100 days averaging time indicating that a lot of measurements with that averaging times have really been done. Best regards Ulrich Bangert -Ursprungliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von Attila Kinali Gesendet: Donnerstag, 14. Juni 2012 07:56 An: Discussion of precise time and frequency measurement Betreff: Re: [time-nuts] Paper about DCF77 performance Hoi Dani! I see you've found the time-nuts as well :-) On Wed, 13 Jun 2012 21:46:56 +0200 Daniel Engeler enge...@alumni.ethz.ch wrote: This is my first post to this mailing list. I wrote a paper about the German longwave time transmitter DCF77 which you may find interesting. Here is the link, unfortunately I am not allowed to post the full PDF: There is an easy way to get around that: Prepare a second paper with more data in it (all that stuff that IEEE tends to get rid of during the publication process) and put that onto your website. http://ieeexplore.ieee.org/xpl/articleDetails.jsp?tp=arnumber=6202411 Performance Analysis and Receiver Architectures of DCF77 Radio-Controlled Clocks, by Daniel Engeler IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control (May 2012) Nice paper. I haven't had time to read it yet, but a few comments after i skimmed it: * you have a lot of simulation and measurments on BER vs SNR. For time-nutty needs that's not so relevant. An ADEV plot would be much more informative on the stability. * Also some data on the absolute timing variations vs time would be nice to have. * Fig 23 shows a very complex board. Given that you only have a relatively simple analog stage and an FPGA i wonder what the rest is for. * You use an LTC1562 8th order bandpass: Do you compensate for it's frequency dependend delay and its variation? Or is negligible compared to the antenna? * Do you do any temperature stabilization? * What kind of reference oscillator do you use? * You talk about 20 to 50ppm variations for XO's, are you aware that these are maximum variation including production variabiltiy and that the stability of an good XO is usually in the range of a few ppm in office conditions (i've measured an XO in a PC that showed a long term (months) stability in the ppb range) * Why did you use an FPGA and not a simple DSP or one of the more powerfull uC's like an Cortex-M3/4? The algorigthms don't look computationally intensive. And that would simplify the development considerably. * Where did you do your measurements? In Schlieren? * What is the application you had in mind while developing this? Attila Kinali -- Why does it take years to find the answers to the questions one should have asked long ago? ___ 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] Paper about DCF77 performance
enge...@alumni.ethz.ch said: Building the best DCF77 receiver in the world :-) You have found the right place. :) -- These are my opinions. I hate spam. ___ 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] Paper about DCF77 performance
On 6/13/2012 3:46 PM, Daniel Engeler wrote: Hi, This is my first post to this mailing list. I wrote a paper about the German longwave time transmitter DCF77 which you may find interesting. Here is the link, unfortunately I am not allowed to post the full PDF: http://ieeexplore.ieee.org/xpl/articleDetails.jsp?tp=arnumber=6202411 Performance Analysis and Receiver Architectures of DCF77 Radio-Controlled Clocks, by Daniel Engeler IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control (May 2012) Abstract: DCF77 is a longwave radio transmitter located in Germany. Atomic clocks generate a 77.5-kHz carrier which is amplitude- and phase-modulated to broadcast the official time. The signal is used by industrial and consumer radio-controlled clocks. DCF77 faces competition from the Global Positioning System (GPS) which provides higher accuracy time. Still, DCF77 and other longwave time services worldwide remain popular because they allow indoor reception at lower cost, lower power, and sufficient accuracy. Indoor longwave reception is challenged by signal attenuation and electromagnetic interference from an increasing number of devices, particularly switched-mode power supplies. This paper introduces new receiver architectures and compares them with existing detectors and time decoders. Simulations and analytical calculations characterize the performance in terms of bit error rate and decoding probability, depending on input noise and narrowband interference. The most promising detector with maximum-likelihood time decoder displays the time in less than 60 s after powerup and at a noise level of Eb/N0 = 2.7 dB, an improvement of 20 dB over previous receivers. A field-programmable gate array-based demonstration receiver built for the purposes of this paper confirms the capabilities of these new algorithms. The findings of this paper enable future high-performance DCF77 receivers and further study of indoor longwave reception. ___ 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. Daniel Might be a great read for us time-nuts. Unfortunately we have no access to the ieee site so it will go unread and appreciated. Regards Paul ___ 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] Paper about DCF77 performance
Would be interesting if I can read it. As far as I know even the IEEE grants the right to the author of his paper to locate it on his own web-site for public download. Thanks - Henry paul schrieb: On 6/13/2012 3:46 PM, Daniel Engeler wrote: Hi, This is my first post to this mailing list. I wrote a paper about the German longwave time transmitter DCF77 which you may find interesting. Here is the link, unfortunately I am not allowed to post the full PDF: http://ieeexplore.ieee.org/xpl/articleDetails.jsp?tp=arnumber=6202411 Daniel Might be a great read for us time-nuts. Unfortunately we have no access to the ieee site so it will go unread and appreciated. Regards Paul -- ehydra.dyndns.info ___ 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] Paper about DCF77 performance
Hi Do they grant the right, or do people just get away with it? Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of ehydra Sent: Wednesday, June 13, 2012 4:24 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Paper about DCF77 performance Would be interesting if I can read it. As far as I know even the IEEE grants the right to the author of his paper to locate it on his own web-site for public download. Thanks - Henry paul schrieb: On 6/13/2012 3:46 PM, Daniel Engeler wrote: Hi, This is my first post to this mailing list. I wrote a paper about the German longwave time transmitter DCF77 which you may find interesting. Here is the link, unfortunately I am not allowed to post the full PDF: http://ieeexplore.ieee.org/xpl/articleDetails.jsp?tp=arnumber=6202411 Daniel Might be a great read for us time-nuts. Unfortunately we have no access to the ieee site so it will go unread and appreciated. Regards Paul -- ehydra.dyndns.info ___ 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] Paper about DCF77 performance
Do they grant the right, or do people just get away with it? We used to get away with it by publishing an in-house research report that was a preliminary version of what turned into the paper. That was many years ago, before the web. We actually printed hard copies. We had good in-house editors so the preliminary version was pretty good, maybe even better if interesting stuff had to be trimmed for the official paper. Matt Blaze has a good blog entry on this mess: Why do IEEE and ACM act against the interests of scholars? http://www.crypto.com/blog/copywrongs/ Daniel: Your timing was interesting. We just had a discussion on this topic a few days ago. If you want to review it, it's in the archives. Subject is Paywall rant, but a few comments probably rolled over to a few other threads. If you don't know how to find the archives, poke me off-list. -- These are my opinions. I hate spam. ___ 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] Paper about DCF77 performance
On 6/13/12 1:38 PM, Bob Camp wrote: Hi Do they grant the right, or do people just get away with it? it is formally granted.. the IEEE instructions for authors or something like that talks about it. You can put your own papers up on your own website, and you make sure you have appropriate attribution, etc. I'll look for the reference. ___ 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] Paper about DCF77 performance
Hoi Dani! I see you've found the time-nuts as well :-) On Wed, 13 Jun 2012 21:46:56 +0200 Daniel Engeler enge...@alumni.ethz.ch wrote: This is my first post to this mailing list. I wrote a paper about the German longwave time transmitter DCF77 which you may find interesting. Here is the link, unfortunately I am not allowed to post the full PDF: There is an easy way to get around that: Prepare a second paper with more data in it (all that stuff that IEEE tends to get rid of during the publication process) and put that onto your website. http://ieeexplore.ieee.org/xpl/articleDetails.jsp?tp=arnumber=6202411 Performance Analysis and Receiver Architectures of DCF77 Radio-Controlled Clocks, by Daniel Engeler IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control (May 2012) Nice paper. I haven't had time to read it yet, but a few comments after i skimmed it: * you have a lot of simulation and measurments on BER vs SNR. For time-nutty needs that's not so relevant. An ADEV plot would be much more informative on the stability. * Also some data on the absolute timing variations vs time would be nice to have. * Fig 23 shows a very complex board. Given that you only have a relatively simple analog stage and an FPGA i wonder what the rest is for. * You use an LTC1562 8th order bandpass: Do you compensate for it's frequency dependend delay and its variation? Or is negligible compared to the antenna? * Do you do any temperature stabilization? * What kind of reference oscillator do you use? * You talk about 20 to 50ppm variations for XO's, are you aware that these are maximum variation including production variabiltiy and that the stability of an good XO is usually in the range of a few ppm in office conditions (i've measured an XO in a PC that showed a long term (months) stability in the ppb range) * Why did you use an FPGA and not a simple DSP or one of the more powerfull uC's like an Cortex-M3/4? The algorigthms don't look computationally intensive. And that would simplify the development considerably. * Where did you do your measurements? In Schlieren? * What is the application you had in mind while developing this? Attila Kinali -- Why does it take years to find the answers to the questions one should have asked long ago? ___ 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.
