Re: [time-nuts] Is possible precise 1pps?
On Wed, 13 Mar 2013 23:51:53 +0100 (CET) hutt...@seznam.cz wrote: NEO-6M buy for less than $ 10 including shipping from China, NEO-6T is unfortunately expensive, and frankly I do not know who sells it for at least a little reasonable prices. The -T models are not that expensive. The problem is that you have to buy them in batches 30 to get down to a reasonable price. U-blox seems to have taken the stance, that small buyers are not really benefitial to their business (which is understandable when you can sell millions of pieces on the chinese market). But they nevertheless support these small buyers trough their webshop where you can buy single pieces (which is far better than most manufacturers who do not sell single pieces at all). Attila Kinali -- The trouble with you, Shev, is you don't say anything until you've saved up a whole truckload of damned heavy brick arguments and then you dump them all out and never look at the bleeding body mangled beneath the heap -- Tirin, The Dispossessed, U. Le Guin ___ 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] Is possible precise 1pps?
Hi, On Wed, 13 Mar 2013 23:51:53 +0100 (CET) hutt...@seznam.cz wrote: NEO-6M buy for less than $ 10 including shipping from China, NEO-6T is unfortunately expensive, and frankly I do not know who sells it for at least a little reasonable prices. The -T models are not that expensive. The problem is that you have to buy them in batches 30 to get down to a reasonable price. U-blox seems to have taken the stance, that small buyers are not really benefitial to their business (which is understandable when you can sell millions of pieces on the chinese market). But they nevertheless support these small buyers trough their webshop where you can buy single pieces (which is far better than most manufacturers who do not sell single pieces at all). Sounds like a time-nuts group buy? I would be interested... Greetings, Pieter. Attila Kinali -- The trouble with you, Shev, is you don't say anything until you've saved up a whole truckload of damned heavy brick arguments and then you dump them all out and never look at the bleeding body mangled beneath the heap -- Tirin, The Dispossessed, U. Le Guin ___ 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] DCF77 PPS
Silly 1,2 instead of 0,0012 fudge: indeed a mistake. How I measured when I wrote the first message: - I waited for a bit to be received - exact after the bit was received and read by my testprogram, I would check what the offset was to a second. e.g 13:45:12.456 would be an offset if 456ms - the linux system returns in microseconds, I would simple discard those 3 extra digits. eg. 13:45:12.456987 would become .456 Saturday night I connected the testprogram to NTP: when a bit was received, I would check how many microseconds after the second the system was and send that to NTPd (like above but doing microseconds here). After a couple of days this gives: remote refid st t when poll reach delay offset jitter == o127.127.20.1.GPS.0 l1 16 3770.000 -0.001 0.002 -192.168.64.1.GPS.1 u 52 64 3760.114 -0.021 0.021 x192.168.62.129 SHM(0) 2 u 49 64 372.080 154.251 82.784 x82.95.142.92129.70.132.363 u 25 64 377 36.867 78.199 1.989 x127.127.28.0.SHM0. 1 l58 3770.000 -263.48 3.437 --- -194.109.22.18 193.79.237.142 u 18 64 377 17.321 -3.490 0.468 -194.109.20.18 193.79.237.142 u 12 64 377 17.292 -3.296 0.776 *193.79.237.14 .PPS.1 u 20 64 377 19.607 -2.342 0.294 +192.87.36.4 .GPS.1 u 64 64 377 21.556 -2.370 0.730 +134.221.205.12 .PPS.1 u 40 64 377 20.372 -2.363 0.441 -172.29.0.11 134.221.205.12 2 u 42 64 377 18.350 -2.479 6.184 The 127.127.28.0 (SHM0) source is the dcf77 pps source. 192.168.62.129 does the same trick by the way using an MSF receiver but lets ignore that for now. Allan deviation plot: http://keetweej.vanheusden.com/~folkert/SHM0-peerstats.2013w10.png Offset plot: http://keetweej.vanheusden.com/~folkert/SHM0-offset.png last 800 measurements: http://keetweej.vanheusden.com/~folkert/SHM0-offset-last800.png So my guestimate is that 259 and 263 are the values to look for and I should ignore the others so that I don't confuse ntpd. That doesn't make sense to me, probably because I don't understand your data collection environment and/or maybe it's dong something strange. Hopefully my explanation above makes it more clear. While writing this I got an epiphany: I think I know what causes the 0.26s offset: the serial port is configured at 50Bps, 8, n, 1. So each byte takes 10 bits (8 data-, 1 start- and 1 stop bit). So a maximum of 5 characters per second or 0,2s per character. Each DCF77 bit is signalled as a byte to the system, so that explains 0,2s of the offset seen. Maybe the receiver needs another 0,6s +/- to convert the received bits into something it can transmit over the TX line of the serial port. What I should do, is open the casing of the receiver and connect the signal coming from the antenna to the DCD pin of that serial port. Do you have a scope? The simplest way to see what's going on would be to trigger on the PPS from the GPS unit and look at the DCF77 signal. I don't have one but in a couple of weeks it is my birthday so maybe then. The result was neither! From visual inspection it looked as if only 3 or 4 different offsets were registered. So I ran 3 tests where I took 120 offset-samples, masked of the microseconds ... How did you mask off the microseconds? Did you do that in binary or drop the right part of an ascii string? If you masked in binary, maybe you got 2 extra bits. I did it the ascii way. E.g.: value = floor(value * 1000.0) / 1000.0; There are 2 parts to decoding something like the DCF77 signal. One is to get an accurate marker for the PPS signal. The other is to figure out the time for each PPS by decoding the pattern of pulse widths. You should be able to see the pulse widths if you capture both sides of the PPS signal. Yes, I read this weekend that 0 and 1 are 100ms versus 200ms. One common way to get a large/strange offset is to use the wrong edge of the PPS signal. If that's what was happening, I'd expect to see several clumps of offsets corresponding to the different pulse widths. I only see one broad clump. It's probably the naive way of measuring (see my epiphany). I wouldn't worry about confusing ntpd, at least not at this level. It has a noise reduction mechanism. It puts all the samples into a fifo. When the driver (PPS/Atom or SHM or ...) gets polled, ntpd sorts the buffer then discards 1/3 of the samples as (potentially crazy) outliers. Thanks regards, Folkert van Heusden -- www.vanheusden.com/multitail - win een vlaai van multivlaai! zorg ervoor dat multitail opgenomen wordt in Fedora Core, AIX, Solaris of HP/UX en win een vlaai naar keuze -- Phone:
[time-nuts] LORAN C is on the air as of 0900 EST Monday
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[time-nuts] SR620: cal error 23
Hi all, While auto calibrating the SR620 I get the message cal error 23 - the manual isn't that specific about this message, it only states, that error numbers 19 to 23 are caused by Stop TAC problems. However, the counter counts, but I can't do automatic calibration any more. Anyone having experience with that? Thanks a lot 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.
Re: [time-nuts] SR620: cal error 23
On Mon, Mar 18, 2013 at 04:28:32PM +0100, Volker Esper wrote: Hi all, While auto calibrating the SR620 I get the message cal error 23 - the manual isn't that specific about this message, it only states, that error numbers 19 to 23 are caused by Stop TAC problems. The manual also states that error codes 19-23 are the same as the start values (n - 16), so 23 minus 16 should be the same as '7' i.e. 'stop linearity byte out of range' However, the counter counts, but I can't do automatic calibration any more. Anyone having experience with that? Sorry, no further experience with that HTH, Herbert Thanks a lot 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] SR620: cal error 23
Am 18.03.2013 18:00, schrieb Herbert Poetzl: The manual also states that error codes 19-23 are the same as the start values (n - 16), so 23 minus 16 should be the same as '7' i.e. 'stop linearity byte out of range' Where do you read that, I can't find it :-/ 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.
Re: [time-nuts] SR620: cal error 23
On Mon, Mar 18, 2013 at 07:34:26PM +0100, Volker Esper wrote: Am 18.03.2013 18:00, schrieb Herbert Poetzl: The manual also states that error codes 19-23 are the same as the start values (n - 16), so 23 minus 16 should be the same as '7' i.e. 'stop linearity byte out of range' Where do you read that, I can't find it :-/ http://ilrs.gsfc.nasa.gov/docs/timing/sr620_manual.pdf page 40, search for 'stop tac' best, Herbert 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] u-blox -6T purchase
On Mon, Mar 18, 2013 at 12:00 PM, Pieter ten Pierick wrote: The -T models are not that expensive. The problem is that you have to buy them in batches 30 Sounds like a time-nuts group buy? Just going by the u-blox shop for North America: NEO-6T u-blox 6 GPS Module Precision Timing 1 - 999 pcs $ 179.00 Which is a bit more than 30 pieces. This compared to: NEO-6M u-blox 6 GPS Module (crystal) 1 - 999 pcs $ 99.00 which seems readily available for about $20 (USD) shipped. I have not contacted u-blox so I don't know if a normal bulk purchase would have price breaks at other points but I haven't seen the -6T for say $50 (USD). ___ 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] SR620: cal error 23
Am 18.03.2013 19:53, schrieb Herbert Poetzl: page 40, search for 'stop tac' Herbert, you are the best :-) I didn't expect the error codes in the programming commands section. I'm afraid it could be a hardware failure. 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.
Re: [time-nuts] Is possible precise 1pps?
It you want a current technology timing GPS with support and a warranty and just need one unit, you can get these for about $60. The specs in the PDF below say it is pretty good. You have to call and ask for the special evaluation prices and say how you heard about it. The receivers are easy to use, all the connections are on one header pin. http://www.synergy-gps.com/images/stories/pdf/m12mt_brochure.pdf On Mon, Mar 18, 2013 at 1:21 AM, Pieter ten Pierick time-nuts-m...@tenpierick.com wrote: Hi, On Wed, 13 Mar 2013 23:51:53 +0100 (CET) hutt...@seznam.cz wrote: NEO-6M buy for less than $ 10 including shipping from China, NEO-6T is unfortunately expensive, and frankly I do not know who sells it for at least a little reasonable prices. The -T models are not that expensive. The problem is that you have to buy them in batches 30 to get down to a reasonable price. U-blox seems to have taken the stance, that small buyers are not really benefitial to their business (which is understandable when you can sell millions of pieces on the chinese market). But they nevertheless support these small buyers trough their webshop where you can buy single pieces (which is far better than most manufacturers who do not sell single pieces at all). Sounds like a time-nuts group buy? I would be interested... Greetings, Pieter. Attila Kinali -- The trouble with you, Shev, is you don't say anything until you've saved up a whole truckload of damned heavy brick arguments and then you dump them all out and never look at the bleeding body mangled beneath the heap -- Tirin, The Dispossessed, U. Le Guin ___ 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. -- 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] SR620: cal error 23
Running Auto Cal a few seconds after switching the counter on, the calibration succeeds, though with values different from the warm ones (who'd have thunk). After warming up, error 23 wins. I have to open it and do the old school trouble shooting with coolant spray... However, any advice, tip, hint would be appreciated. Thank you Volker Am 18.03.2013 20:33, schrieb Volker Esper: Am 18.03.2013 19:53, schrieb Herbert Poetzl: page 40, search for 'stop tac' Herbert, you are the best :-) I didn't expect the error codes in the programming commands section. I'm afraid it could be a hardware failure. 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] u-blox -6T purchase
I thought there was someplace where you can get them for $35 or $60. Check the archives Sent from mobile On Mar 18, 2013, at 1:23 PM, Paul tic-...@bodosom.net wrote: On Mon, Mar 18, 2013 at 12:00 PM, Pieter ten Pierick wrote: The -T models are not that expensive. The problem is that you have to buy them in batches 30 Sounds like a time-nuts group buy? Just going by the u-blox shop for North America: NEO-6T u-blox 6 GPS Module Precision Timing 1 - 999 pcs $ 179.00 Which is a bit more than 30 pieces. This compared to: NEO-6M u-blox 6 GPS Module (crystal) 1 - 999 pcs $ 99.00 which seems readily available for about $20 (USD) shipped. I have not contacted u-blox so I don't know if a normal bulk purchase would have price breaks at other points but I haven't seen the -6T for say $50 (USD). ___ 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] TIE measurement for arbitrary frequency oscillator
Hi all! First time poster here, but I've been lurking for a couple months and found this place to be highly informative. I want to measure TIE for a 7.362 MHz oscillator. Ultimately, I want to process into TDEV and MTIE. 1) Is it acceptable to use the DMTD method and set a signal generator (driven by rubidium) as the reference frequency to a value equal to the oscillator's? 2) If not, can you point me to a more proper way of doing this type of measurement for arbitrary frequencies that are not easily divisible into 10 MHz? Thank you! ___ 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] TIE measurement for arbitrary frequency oscillator
John, Besides buying an expensive source analyzer that will cost $10K or more, a high quality frequency counter should do the job. You could also use a cheap pld or PicTic to generate a 1PPS from your oscillator then use the counter to compare the 1pps to your reference 1pps for phase drift to calculate mtie. Then use Ulrich Bangerts free Plotter utility to do the analysis. Bye Said Sent From iPhone On Mar 18, 2013, at 21:10, John Doering johndoerin...@gmail.com wrote: Hi all! First time poster here, but I've been lurking for a couple months and found this place to be highly informative. I want to measure TIE for a 7.362 MHz oscillator. Ultimately, I want to process into TDEV and MTIE. 1) Is it acceptable to use the DMTD method and set a signal generator (driven by rubidium) as the reference frequency to a value equal to the oscillator's? 2) If not, can you point me to a more proper way of doing this type of measurement for arbitrary frequencies that are not easily divisible into 10 MHz? Thank you! ___ 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.
