[time-nuts] European Frequency and Time Seminars 2015
Fellow time-nuts, I spent last week at the European Frequency and Time Seminars 2015 in Besancon, France. It was a week full of seminars and also labsessions. It was a nice mixture of phase-noise, stability measures, GNSS, fibre-based time and frequency transfer, atomic clocks, laser cooling, crystal oscillators etc. from a distinguished set of lectures. This was the third run, with the assistance of Prof. Enrico Rubiola. Sharing lunch and sometimes breakfast or dinner with these lectures sure helped to spread the knowledge. Enrico was eager to share knowledge and answer questions, turning the paper table tablet upside down to draw and explain over lunch. Some of the labs stood out as good labs, and that includes Francois Vernottes data-analysis lab which illustrated the ADEV and MDEV uses, so that you needed MDEV to separate noises. It illustrated the linear drift limitations and how you can use either HDEV or drift-removal to recover the actual noise below that limit. All this using his Sigma THETA tool: https://theta.obs-besancon.fr/spip.php?article103lang=fr As a side-note, the question came up about delta-counters and the claim of using MDEV to process it correctly. Francois and I teamed up to explain why it does not work, and how the hockey-puck/droop response shapes. Later in the week I saw a diagram that had that response as measured for an optical clock, so I turned to Attila, waved my finger and said Bad science! Bad science!. The analysis of Omega-counters (those using linear regression for frequency estimation) triggered the discovery of the PDEV measure. However, there you use m-altering weighing rather than the typical fixed width filtering of delta and omega counters. The GNSS time transfer lecture of Pascale Defraigne from the Royal Observatory of Belgium was also interesting, showing her CGGTTS methods for comparing clocks between labs and also for the PPP stuff. The WhiteRabbit lecture was interesting, and the lab-session was really impressive in all its simplicity. CERN has certainly been thinking about how things should work. Thomasz was also a great guy to hang out with. Learning about pulsars and the efforts to measure those was also interesting. Also get to learn about DROs, CPT etc. through the combination of labs and lab-visits was interesting. We also got a tour of their crystal/resonator lab, which is where they did the research of the BVA. A particular nice exercise was to visit their observatory and then later on see Jupiter and three moons as well as Venus in the same view. Sharing this experience with fellow time-nut Attila Kinali was nice, and we picked up additional friends on the way, such as Guilermo who does MEMS design in his PhD and William that does Ca+ ion clocks in his PhD. As we could not stop talking we ended up in Enricos office and as we where migrating out of that we joined forces with another professor for a nice evening dinner on Friday, which included integration of flicker noise from an estimate of universes total age to the frequency so high it creates a black hole and ending up with just above 22 dB over the white noise floor. Epic moment! We also had a very good time and good food. The heat was considerable, so for a northerner like me it was a bit of a challenge, but I managed to cope with it better over the week. For people wanting to learn more about this, do consider going to the EFTS next year. Oh, before going to Besancon I came first to Geneva so I could do a presentation at CERN and meet up with the White Rabbit team. They where generous and showed me around! As I was going to Paris I was also setup with a contact at SYRTE as part of Observatoir de Paris, so I got a nice visit of SYRTE too. Did some other visits there, including some form of temporary tower that Gustaf Eiffel seems to have left behind, it's a L-beam marvel. 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] Attila Kinali's Request for inductance information
Fred, His Introduction to Electromagnetic Compatibility is also a good book. He isn't skipping past things, he explains them in depth. Haven't seen his Inductance book, so I might need to get that one then. Cheers, Magnus On 06/27/2015 01:48 AM, fre...@sprynet.com wrote: Long-time lurker here. Attila, you might find the book Inductance: Loop and Partial by Clayton Paul to be what you're looking for. IEEE Press / Wiley --Fred Message: 14 Date: Fri, 26 Jun 2015 14:34:15 +0200 From: Attila Kinali att...@kinali.ch To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] magnetic electronic components Message-ID: 20150626143415.202ea02460c2cb4b21294...@kinali.ch Content-Type: text/plain; charset=UTF-8 Moin! Thanks for all the answers and sorry for my late reply. I tried to at least skim trough the suggestions before. I would like to reply in one big mail instead of many small ones, in order not to clutter the mailinglist too much. On Tue, 23 Jun 2015 00:15:29 +0100 Adrian Godwin artgod...@gmail.com wrote: Although it's published by a vendor, this applications manual has a lot of useful information. http://www.we-online.com/web/en/electronic_components/produkte_pb/fachbuecher/Trilogie.php Even though, I do not own a copy of The Trilogy, I know of it. It does a good job of covering the basics. But unfortunately, it does not contain much about the theoretical background, so does not help much in understanding how to work around the physical limits of cores. Other than that, I would recommend this book to every practicioning electrical engineer. On Mon, 22 Jun 2015 18:56:02 -0500 Bob kb8tq kb...@n1k.org wrote: You have two choices: 1) Read the physics stuff 2) Go back far enough that the divide had not occurred ( = 1950’s). Sorry about that …. Yes. I came to a similar conclusion. What irks me is, that this is the conclusion I came to with many topics in electrical engineering. At some point people decide that it is either too difficult to deal with or a solved problem and ignore it completely from then on. And if you are an engineer who tries to actually understand things instead of just repeating what some senior engineer told you long long ago, then you run up against walls. :-( On Mon, 22 Jun 2015 20:24:14 -0700 Jim Lux jim...@earthlink.net wrote: the best, and probably the only, book is the one by E.C. Snelling. http://www.amazon.com/Soft-ferrites-properties-applications-Snelling/dp/0592027902 1969 edition is https://archive.org/details/SNELLING__SOFT-FERRITES__1969 and it's not like the properties of magnetic fields have changed. Cool! Thanks a lot! I was looking for this, but couldn't find it. I somehow missed that archive.org had a copy. On Tue, 23 Jun 2015 07:25:57 -0400 Tim Shoppa tsho...@gmail.com wrote: Here in the USA, iron powder and ferrite cores of many different materials, sizes, and a few shapes are available from Amidon and kitsandparts.com. Many useful ferrite cores for multi-turn transformers and chokes, are sold as EMI beads by Mouser and Newark and other mainline distributors. I don't know too much about easy availability in EU. Buying cores is not much of a problem. For one there are the distributors you have mentioned, for another we have companies like Würth here in Germany and Coilcraft in the US who are no afraid of selling single pieces (if they dont just regard it as samples). BTW: I really like to work with Würth. I know very few components companies that go so much out of their way to help a struggling engineer to get his project done. And they never ask about the volume of your project. You need help, you get help. Thanks for all the replies and suggesttion. And sorry if I don't answer all of them individually. 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. ___ 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] beaglebones, time, web services
Since you want simple just use a CGI script written in your language of choice. Very easy technology to learn, Python has support libraries out of the box if you want. You have a webpge with carious simple controls on it like buttons etc, you click a special button that posts a request to a URL, the webserver runs a script that generates the response, the webserver serves it out, your browser displays it. Why bother with learning a framework? Messing about with mechanics is far more fun! Tom Harris celephi...@gmail.com On 4 July 2015 at 23:13, Jim Lux jim...@earthlink.net wrote: I've got a project I'm working on to make a sophisticated sundial with moving mirrors. I've got a batch of Arduinos that move the mirrors to the appropriate places, given the current sun angle, etc. I've got a beaglebone that runs some python code to calculate sun angle based on time The beaglebone will have a GPS feeding it to get time. BUT now, I'd like to add a web interface, so that it can be manipulated by a mobile device using a browser. One way I can think of is to run some sort of limited web server. there are a couple that come with the beaglebone, including the python simplehttpserver. But I'm sort of stuck on the interface between the webserver and the other code running. I've done this kind of thing where the one task goes out and updates files in the tree that's being served by the web server, and that works fine for status display kinds of things that don't update very quickly. It's also nicely partitioned. but I want to be able to change the behavior of the system (e.g. by having the server respond to a PUT or something) Is the best scheme to go in and modify the webserver code to look for specific URLs requested, and then fire off some custom code to do what I want? I'm not particularly interested in javascript, and would prefer python. Or are there libraries that make this more cookbook? (the little getting started with beaglebone book talks about flask) There's quite a few websites out there where someone has done some sort of home automation, but they tend to be a bit light on the analysis of pros and cons of implementation architectures: I built X using Y and Z and it sort of works. Actually, along a similar line.. my solar position code isn't very pretty (it's sort of replicating some code I wrote in Basic a long time ago, with some changes from stuff I cribbed from ccmatlab). If someone knows of a python package that just does this, I'd love to hear about it. Either Az El, or X,Y,Z in ECI or ECF would do. ___ 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] beaglebones, time, web services
Yes cgi scripts take a few hours to learn and take only a small processor. Drubbing a dims and all is overkill and will not perform well on the BBB. On Monday, July 6, 2015, Tom Harris celephi...@gmail.com wrote: Since you want simple just use a CGI script written in your language of choice. Very easy technology to learn, Python has support libraries out of the box if you want. You have a webpge with carious simple controls on it like buttons etc, you click a special button that posts a request to a URL, the webserver runs a script that generates the response, the webserver serves it out, your browser displays it. Why bother with learning a framework? Messing about with mechanics is far more fun! Tom Harris celephi...@gmail.com javascript:; On 4 July 2015 at 23:13, Jim Lux jim...@earthlink.net javascript:; wrote: I've got a project I'm working on to make a sophisticated sundial with moving mirrors. I've got a batch of Arduinos that move the mirrors to the appropriate places, given the current sun angle, etc. I've got a beaglebone that runs some python code to calculate sun angle based on time The beaglebone will have a GPS feeding it to get time. BUT now, I'd like to add a web interface, so that it can be manipulated by a mobile device using a browser. One way I can think of is to run some sort of limited web server. there are a couple that come with the beaglebone, including the python simplehttpserver. But I'm sort of stuck on the interface between the webserver and the other code running. I've done this kind of thing where the one task goes out and updates files in the tree that's being served by the web server, and that works fine for status display kinds of things that don't update very quickly. It's also nicely partitioned. but I want to be able to change the behavior of the system (e.g. by having the server respond to a PUT or something) Is the best scheme to go in and modify the webserver code to look for specific URLs requested, and then fire off some custom code to do what I want? I'm not particularly interested in javascript, and would prefer python. Or are there libraries that make this more cookbook? (the little getting started with beaglebone book talks about flask) There's quite a few websites out there where someone has done some sort of home automation, but they tend to be a bit light on the analysis of pros and cons of implementation architectures: I built X using Y and Z and it sort of works. Actually, along a similar line.. my solar position code isn't very pretty (it's sort of replicating some code I wrote in Basic a long time ago, with some changes from stuff I cribbed from ccmatlab). If someone knows of a python package that just does this, I'd love to hear about it. Either Az El, or X,Y,Z in ECI or ECF would do. ___ time-nuts mailing list -- time-nuts@febo.com javascript:; 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 javascript:; To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Chris Albertson Redondo Beach, California ___ 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] beaglebones, time, web services
On 7/6/15 3:19 PM, Tom Harris wrote: Since you want simple just use a CGI script written in your language of choice. Very easy technology to learn, Python has support libraries out of the box if you want. You have a webpge with carious simple controls on it like buttons etc, you click a special button that posts a request to a URL, the webserver runs a script that generates the response, the webserver serves it out, your browser displays it. Why bother with learning a framework? Messing about with mechanics is far more fun! The only hiccup with the cgi approach (and with directly code the action in the guts of the server like with flask) is that the subprocess that's spawned has to complete before control returns (e.g. to serve stdout to the user). So if you want to fire off a task that will run in parallel with the webserver's other stuff, you need to have some sort of interprocess communication (e.g. a named pipe, socket, file, MPI communicator, etc.). (or you do something like run at or batch, which is basically using a file as a interprocess communication, and the at daemon watches the file) ___ 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] New wrist watch
With my new found interest in time nuttiness I thought I should upgrade to a decently accurate watch. I had some features I was looking for and settled on a Casio Wave Ceptor. My second choice was an Eco Drive, but the Casio had the right mix of features at a good price. As I was sitting outside reading the manual after buying it, I laid it flat on the table and started a manual sync to WWVB. The UI is pretty intuitive for having so few buttons and indicators. It quickly told me that it had found a stable signal, and about six minutes later it was synced. Pretty cool. Anyone know what the drift is like in this watch if it can't find the signal for several days/weeks? I would hope that actual performance is a little better than the +/- 15 sec per month stated in the manual. I should trap it in a faraday bag for a while to test it... Dan ___ 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] Controlling the 5370A via GPIB
I need to capture the time between the PPS and the OCXO on my GPSDO to fine-tune my calibration curve. I'm having good luck doing this with my 5335A, which of course, has less resolution than my 5370A. But, when I setup the 5370A with what I think is the right setup, every 6th or 7th value is off by many ns. If you have experience capturing a 5370A over GPIB under this type of circumstance and are willing to take a look at my GPIB setup commands, could you contact me off list? Bob - AE6RV bob at evoria.net ___ 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] beaglebones, time, web services
Keep it simple, use a Cgi bin script. Your url is can be any executable. Any language you like. The script can do anything and then it writes out html to stdout. Simple enough. . On Saturday, July 4, 2015, Jim Lux jim...@earthlink.net wrote: I've got a project I'm working on to make a sophisticated sundial with moving mirrors. I've got a batch of Arduinos that move the mirrors to the appropriate places, given the current sun angle, etc. I've got a beaglebone that runs some python code to calculate sun angle based on time The beaglebone will have a GPS feeding it to get time. BUT now, I'd like to add a web interface, so that it can be manipulated by a mobile device using a browser. One way I can think of is to run some sort of limited web server. there are a couple that come with the beaglebone, including the python simplehttpserver. But I'm sort of stuck on the interface between the webserver and the other code running. I've done this kind of thing where the one task goes out and updates files in the tree that's being served by the web server, and that works fine for status display kinds of things that don't update very quickly. It's also nicely partitioned. but I want to be able to change the behavior of the system (e.g. by having the server respond to a PUT or something) Is the best scheme to go in and modify the webserver code to look for specific URLs requested, and then fire off some custom code to do what I want? I'm not particularly interested in javascript, and would prefer python. Or are there libraries that make this more cookbook? (the little getting started with beaglebone book talks about flask) There's quite a few websites out there where someone has done some sort of home automation, but they tend to be a bit light on the analysis of pros and cons of implementation architectures: I built X using Y and Z and it sort of works. Actually, along a similar line.. my solar position code isn't very pretty (it's sort of replicating some code I wrote in Basic a long time ago, with some changes from stuff I cribbed from ccmatlab). If someone knows of a python package that just does this, I'd love to hear about it. Either Az El, or X,Y,Z in ECI or ECF would do. ___ 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. -- Chris Albertson Redondo Beach, California ___ 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] GPS/UTC time
So, what *is* the ADEV of the earth's rotation? http://leapsecond.com/museum/earth/ /tvb ___ 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] leap second video from NICT Japan
Hi, On 07/05/2015 04:09 PM, dikshie wrote: On Sun, Jul 5, 2015 at 7:52 PM, John C. Westmoreland, P.E. j...@westmorelandengineering.com wrote: Hello Dikshie, Thanks for sharing this. Wow, not sure we had anything in the US that was comparable - crowd actually applauded. sorry for wrong url. the previous one was 2012. the 2015 leap second video is here: https://www.youtube.com/watch?v=mQvwMgwTMNs Nice that it is such a public event as it occurs 9 in the morning, that it is convenient for everyone to see it. Here it occured 2 in the night, so even if I where at a the European Time and Frequency Seminars, we all slept it through. I at one time had to answer when various countries introduce the leapsecond, as if it where a national decision, but they failed to understand that it occurs in the underlying UTC time-scale, so that is why it shifts in Japan at 9 in the morning. Thank you for sharing the link. They joy of kids was nice to see. :) 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] beaglebones, time, web services
If looking at using the bbb for driving steppers. http://blog.machinekit.io/p/hardware-capes.html?m=1 /Björn ___ 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.
