Re: [time-nuts] GPS W/10KHz
Re Bob's comments- This article is relevant. http://www.g4jnt.com/10MHz_Reference_Source_Stability.pdf DaveB, NZ - Original Message - From: Bob Camp li...@rtty.us To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sunday, February 09, 2014 5:22 AM Subject: Re: [time-nuts] GPS W/10KHz Hi The 10 KHz that these modules put out is not very “clean” in terms of driving a synthesizer. If you are looking at taking it straight to RF (as in driving a VHF radio), you likely will be less than happy with the result. Bob On Feb 8, 2014, at 8:02 AM, Alex Pummer a...@pcscons.com wrote: Thank you very much, 73 KJ6UHN Alex On 2/7/2014 8:10 PM, Perry Sandeen wrote: List, Wrote: where is a good source of GPS receiver modules I need one which has 10kHz output to phase lock a quartz oscillator. Fluke.1 Motorola ONCORE M12+T timing gps receiver 1pps 100hz eBay item number:290656401551 Also RDR There is another china seller that has them(10KHz) with leads for $90 but is almost impossible to find. Last time I searched it took me a hour. But he has a wide assortment. I forgot to bookmark his site. Regards, Perrier ___ 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. ___ 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] How I got my FE-5680A to lock in Sydney, Australia
On 09/02/14 02:57, Jamieson (Jim) Rowe wrote: Hi Magnus, Thanks again for those further suggestions. I do have a GPSDO, and I had been able to use it with a counter to check that the FE-5680A was swinging either side of 10MHz. But I didn't make sure that it was swinging evenly each side of 10MHz . According to my notes it was swinging between 9.999770 and 10.36MHz -- i.e., about 230Hz low and about 36Hz high. But it was spending more of the time below 10MHz than above -- does this suggest to you that I should tweak C217 until it swings by about the same amount either way? Yes, that is exactly what I would do. 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] How I got my FE-5680A to lock in Sydney, Australia
On 09/02/14 06:37, Mark Sims wrote: What was the timebase for your counter? I suspect that it is off freq and the Rb is not actually making it above 10 MHz. Inverting the Rb is causing a 2G shift in gravity to the Rb crystal probably shifting its freq enough to cause lock. This is what I have been thinking about, and adjusting the VCXO frequency should help. It would be interesting to confirm the 2G shift before adjustment. 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] Rb as source for ADEV?
On 09/02/14 05:48, Hal Murray wrote: b...@evoria.net said: Would I learn anything useful by hooking my Rb standard up to my 5335A and comparing that to the OCXO? What kind of time-nut question is that? :) Try it and see. Maybe you will find something interesting where you/we didn't expect it. If you assume the Rb is stable, you should be able to watch the long term drift of the OCXO. You can also see temperature variations. How many low digits can you get out of the 5335A? Has 1 ns resolution. Can do averaging on it's own but I rather use TimeLab or something. Do you have an GPSDO to add to the mix? That would let you calibrate the Rb. And you can measure the long-term drift of your rubidium with the same setup. 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] BC637PCI 1024 week rollover
Oh well, full credit to Mr Trimble for getting it right, he does bake exceedingly nice GPS modules and the Ace3 doesn't have a rollover issue and it does report the date correctly. Unfortunately, as far as I can tell anyway, the BC637PCI takes the raw GPS time data from the Ace3 and performs its own calculation which is where the problem seems to occur, certainly it's a 1024 week issue with the date from the BC637 being displayed as June 26 1994 in all versions of the associated demo software. It is possible to set the date correctly but the next packet from the GPS module promptly overwrites it again. I still don't recall seeing this before, although with two boards behaving in the same fashion I'm having doubts about that, but more to the point these boards indicate a firmware date of 2003 which implies they were put into the field like this, and that doesn't make much sense either. Any ideas anyone?, and again has anyone else seen this and/or am I missing something glaringly obvious? Regards Nigel GM8PZR ___ 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] Line Frequency
This probably came up during the recent discussion of Line Frequency Monitoring but I may have missed it. Does any one have a circuit (tested - operational) for monitoring line frequency? I'd like something that checks zero crossing so that it is relatively insensitive to line voltage variations. Simon Engineering is the art of making what you want from what you can get at a profit. ___ 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] BC637PCI 1024 week rollover
On 09/02/14 12:56, gandal...@aol.com wrote: Oh well, full credit to Mr Trimble for getting it right, he does bake exceedingly nice GPS modules and the Ace3 doesn't have a rollover issue and it does report the date correctly. Unfortunately, as far as I can tell anyway, the BC637PCI takes the raw GPS time data from the Ace3 and performs its own calculation which is where the problem seems to occur, certainly it's a 1024 week issue with the date from the BC637 being displayed as June 26 1994 in all versions of the associated demo software. It is possible to set the date correctly but the next packet from the GPS module promptly overwrites it again. I still don't recall seeing this before, although with two boards behaving in the same fashion I'm having doubts about that, but more to the point these boards indicate a firmware date of 2003 which implies they were put into the field like this, and that doesn't make much sense either. Any ideas anyone?, and again has anyone else seen this and/or am I missing something glaringly obvious? If the ACE3 gives correct date, but the BC637 FW does not, then it is obvious that the FW does the unwrapping itself just like a problematic GPS receiver would. Most probably would the ACE3 have issues if it looses it's CMOS backup. I haven't looked at those details, but you should be able to disable the date from being set by the GPS. Maybe play around there. Might be that the FW needs an update, which naturally may not be in existence. Can you read-out the EPROM? Only proves to show that my comment that NTPD needs to do the 1024 week correction for other GPS dependent drivers than the NMEA (NTP bug 2466) is a correct assumption. See the posting I forwarded yesterday. 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] BC637PCI 1024 week rollover
Hello, I'll be glad to check my GPS module to see what is going on there, however I am still waiting for the GPS antenna to be delivered. I tried to use some small form factor Trimple GPS antenna with BC637, but on-board GPS module couldn't lock with it. So, my BC637 is working in freerun mode now: Time Settings: Mode : Free Run Time Format: Binary Year : 2014 Local Offset : 0.0 Propagation Delay : 0 Current Leap Seconds : 0 Scheduled Leap Event Time : 1391731200 Scheduled Leap Event Flag : Insertion GPS Time Format: UTC Format IEEE Daylight Savings Flag : Enable I have no issues with date stamp in that mode: Binary Time: 02/09/2014 14:36:19.7005289 Status: 0 Binary Time: 02/09/2014 14:36:19.7105941 Status: 0 Binary Time: 02/09/2014 14:36:19.7206589 Status: 0 Even if I switch BC637 to GPS mode, it still using correct date. Which is expected, because in accordance with documents, if GPS is not locked, BC637 will behave in the same way as free run. The difference is the Status. Its shows, four bits. And one of them indicates that GPS is not locked: Binary Time: 02/09/2014 14:37:43.0045326 Status: 7 Binary Time: 02/09/2014 14:37:43.0146051 Status: 7 Binary Time: 02/09/2014 14:37:43.0246776 Status: 7 As soon as I'll get my bullet GPS antena attached, I'll see what is going on there for the date stamp. Also, in the documents, I saw some sections, which explain how to use data registers to send some command to Trimble GPS. Probably its is possible to do some corrections through that procedure. May be it is possible to attach another GPS module to the BC637 card. Its using 9 pin connector. This connector is used primarily for connecting the ACE III GPS. Data communications between the board and the GPS receiver are via serial signals. Additionally, the GPS receiver provides a 1 PPS signal to the board. Regards, V.P. On 2014-02-09 06:56, gandal...@aol.com wrote: Oh well, full credit to Mr Trimble for getting it right, he does bake exceedingly nice GPS modules and the Ace3 doesn't have a rollover issue and it does report the date correctly. Unfortunately, as far as I can tell anyway, the BC637PCI takes the raw GPS time data from the Ace3 and performs its own calculation which is where the problem seems to occur, certainly it's a 1024 week issue with the date from the BC637 being displayed as June 26 1994 in all versions of the associated demo software. It is possible to set the date correctly but the next packet from the GPS module promptly overwrites it again. I still don't recall seeing this before, although with two boards behaving in the same fashion I'm having doubts about that, but more to the point these boards indicate a firmware date of 2003 which implies they were put into the field like this, and that doesn't make much sense either. Any ideas anyone?, and again has anyone else seen this and/or am I missing something glaringly obvious? Regards Nigel GM8PZR ___ 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. -- WBW, V.P. ___ 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] TARP TADD-3 and T-BOLT
Hello, I have a quick question about TADD-3 Pulse-per-Second Distribution Amplifier. Does anybody tried to use TADD-3 with Trimble T-Bolt in the configuration, when its using 1PPS and 10MHZ as TADD-3 inputs. The idea is to use TADD-3 to share BOTH t-bolt frequency outputs. Thanks ! -- WBW, V.P. ___ 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 W/10KHz
I have made a design with the 10KHz for usage on the OZ7IGY beacon project, I can mail you the diagram and support you with a PCB if you so whish :) http://rudius.net/oz2m/ngnb/gps.htm It have 2 times 10MHz outputs, the stability is less than 5 mHz. Designed for Rockwell Jupiter GPS receivers TU30, TU40 and TU60 series Michael, OZ2ELA -Oprindelig meddelelse- Fra: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] På vegne af ewkeh...@aol.com Sendt: 8. februar 2014 23:50 Til: time-nuts@febo.com Emne: Re: [time-nuts] GPS W/10KHz The problem with the PLL analog version is the same as with any digital GPSDO. The saw tooth is present at 10 KHz just like 1 Hz. To the best of my knowledge there is no GPS receivers out there for less than $ 1000 with out saw tooth. Timing receivers output the correction value and you can either with software or a variable delay do correction. I encourage you to pursue your idea since for more than ten years I had the privilege to communicate with some of the sharpest minds on that subject and obviously the missed something. That also applies for the three of us that have been working intensely on developing and testing the next generation of GPSDO's that we hope to introduce to time nuts soon. In the meantime with the ever increasing price of Tbolts, Shera is worth a second look. When we worked on the last code release of Shrea using a Morion we got consistently better than 1 E-11. Yes some of the IC's are hard to find and that is why I used more readily available parts and did a new board layout. Also did one using a $ 1.20 Altera gate array. Bert Kehren In a message dated 2/8/2014 12:33:48 P.M. Eastern Standard Time, albertson.ch...@gmail.com writes: On Sat, Feb 8, 2014 at 3:44 AM, Volker Esper ail...@t-online.de wrote: you don't need 10kHz to build a GPS disciplined oscillator. GPSDOs are build with control loop response times in the range of some hours, so the loop will be absolutely happy with a 1PPS input. Of course you are correct. Most GPSDOs are driven with a 1Hz pulse. But I think maybe the OP is not building just any GPSDO but maybe he is looking to repair a specific GPSDO that is designed to use the old (and now rare) Rockwell GPS. If that is the case he needs the old Rockwell or needs to redesign his system. If you are starting from scratch to build a new GPSDO it's easier now. All you need is some kind of a phase detector (74HC4046 ?) and a small uP that has a good built-in DAC. The uP checks the phase once per second and adjusts it'sDAC accordingly. -- 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. ___ 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] Rb as source for ADEV?
Hi Hal, I'm thinking about doing it, but I'm still doing extended tests of my GPSDO with the 5334B. So in order to get access to the 5335A, I'll have to write a server for my Prologix GPIB Ethernet adapter. I've got a lot of time nuts projects stacked up, and it looks like the GPIB server is going to be key to all of them. Bob - AE6RV From: Hal Murray hmur...@megapathdsl.net To: Bob Stewart b...@evoria.net; Discussion of precise time and frequency measurement time-nuts@febo.com Cc: hmur...@megapathdsl.net Sent: Saturday, February 8, 2014 10:48 PM Subject: Re: [time-nuts] Rb as source for ADEV? b...@evoria.net said: Would I learn anything useful by hooking my Rb standard up to my 5335A and comparing that to the OCXO? What kind of time-nut question is that? :) Try it and see. Maybe you will find something interesting where you/we didn't expect it. If you assume the Rb is stable, you should be able to watch the long term drift of the OCXO. How many low digits can you get out of the 5335A? Do you have an GPSDO to add to the mix? That would let you calibrate the Rb. -- 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] Line Frequency
The PicPET is what I use. Input is from a 5v ac transformer. Seems simple to me. I bought a handful of these. Love em. http://www.leapsecond.com/pic/picpet.htm Doc Sent from mobile On Feb 9, 2014, at 7:53 AM, M. Simon msimon6...@yahoo.com wrote: This probably came up during the recent discussion of Line Frequency Monitoring but I may have missed it. Does any one have a circuit (tested - operational) for monitoring line frequency? I'd like something that checks zero crossing so that it is relatively insensitive to line voltage variations. Simon Engineering is the art of making what you want from what you can get at a profit. ___ 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] Line Frequency
Bill, I was hoping to avoid a device that was dependent on line voltage (rather than zero crossings) for timing as it will then be line voltage sensitive (or at least more than a zero crossing detector). Of course zero voltage (zero crossing) detectors have other problems. Susceptibility to line noise being one major one. Simon Engineering is the art of making what you want from what you can get at a profit. On Sunday, February 9, 2014 3:25 PM, Bill Dailey docdai...@gmail.com wrote: The PicPET is what I use. Input is from a 5v ac transformer. Seems simple to me. I bought a handful of these. Love em. http://www.leapsecond.com/pic/picpet.htm Doc Sent from mobile On Feb 9, 2014, at 7:53 AM, M. Simon msimon6...@yahoo.com wrote: This probably came up during the recent discussion of Line Frequency Monitoring but I may have missed it. Does any one have a circuit (tested - operational) for monitoring line frequency? I'd like something that checks zero crossing so that it is relatively insensitive to line voltage variations. Simon Engineering is the art of making what you want from what you can get at a profit. ___ 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] Rb as source for ADEV?
Bob, If you want a C++ class to talk to the Prologix Ethernet, I have one. (I don't have a USB version, but that would just be a matter of implementing a simple subclass to do the communication with the device.) I also have code that uses the above and talk to a 5335A and to a 5370A, both of which like to sulk if you don't do things in the right order. It's written for Windows and should compile in the _free_ Visual Studio Express 2012 (it used to, but the last time I built it was with the full version). Porting to Linux/Mac/iOS would be easy enough... maybe I'll do iOS for fun, if Xcode doesn't sulk and stays alive long enough that is; the only thing Xcode does fast for me is crash! Licensing for all but the findAdapters method will be LGPL once I put headers in. findAdapters() is derived from John Miles's GPIB library and subject to its licensing. Orin, KJ7HQ On Sun, Feb 9, 2014 at 7:36 AM, Bob Stewart b...@evoria.net wrote: Hi Hal, I'm thinking about doing it, but I'm still doing extended tests of my GPSDO with the 5334B. So in order to get access to the 5335A, I'll have to write a server for my Prologix GPIB Ethernet adapter. I've got a lot of time nuts projects stacked up, and it looks like the GPIB server is going to be key to all of them. Bob - AE6RV From: Hal Murray hmur...@megapathdsl.net To: Bob Stewart b...@evoria.net; Discussion of precise time and frequency measurement time-nuts@febo.com Cc: hmur...@megapathdsl.net Sent: Saturday, February 8, 2014 10:48 PM Subject: Re: [time-nuts] Rb as source for ADEV? b...@evoria.net said: Would I learn anything useful by hooking my Rb standard up to my 5335A and comparing that to the OCXO? What kind of time-nut question is that? :) Try it and see. Maybe you will find something interesting where you/we didn't expect it. If you assume the Rb is stable, you should be able to watch the long term drift of the OCXO. How many low digits can you get out of the 5335A? Do you have an GPSDO to add to the mix? That would let you calibrate the Rb. -- 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. ___ 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] Line Frequency
Hi Simon, 1) You can use the picPET to measure zero crossings; just bias the input. 2) With no external parts at all the picPET is a 2.5V crossing detector. 3) What you find when you start playing with 60 Hz is that this is not a problem. That's why few/none of us bother with it. 4) The time of 60 Hz varies so much minute to minute or hour to hour that line voltage effects are mostly irrelevant. 5) The picPET input is pin5, which is a Schmitt trigger input. 6) Schmitt trigger or not, line noise is no problem for a time-stamping counter anyway. What level of precision are you after? /tvb (i5s) On Feb 9, 2014, at 8:04 AM, M. Simon msimon6...@yahoo.com wrote: Bill, I was hoping to avoid a device that was dependent on line voltage (rather than zero crossings) for timing as it will then be line voltage sensitive (or at least more than a zero crossing detector). Of course zero voltage (zero crossing) detectors have other problems. Susceptibility to line noise being one major one. Simon Engineering is the art of making what you want from what you can get at a profit. On Sunday, February 9, 2014 3:25 PM, Bill Dailey docdai...@gmail.com wrote: The PicPET is what I use. Input is from a 5v ac transformer. Seems simple to me. I bought a handful of these. Love em. http://www.leapsecond.com/pic/picpet.htm Doc Sent from mobile On Feb 9, 2014, at 7:53 AM, M. Simon msimon6...@yahoo.com wrote: This probably came up during the recent discussion of Line Frequency Monitoring but I may have missed it. Does any one have a circuit (tested - operational) for monitoring line frequency? I'd like something that checks zero crossing so that it is relatively insensitive to line voltage variations. Simon Engineering is the art of making what you want from what you can get at a profit. ___ 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] Line Frequency
I kind of like the synchronized oscillator on page 6 of this pdf http://cds.linear.com/docs/en/application-note/an12fa.pdf They claim good results. I may have to build one and see. Engineering is the art of making what you want from what you can get at a profit. On Sunday, February 9, 2014 7:44 PM, Chris Albertson albertson.ch...@gmail.com wrote: All you need to monitor line frequency is a small transformer connected to a computer's DCD pin on a serial port. You can get fancier and use comparator, opto isolation and so on but a simple 5V transformer is enough. This takes advantage of the electronics inside the RS232 port that is designed to handle positive and negative voltages up to about +/- 12 volts. Then the linux pulse per second driver will time stamp and log every cycle with the internal clock. It is accurate to a couple microseconds. Don't worry about line noise because that is what you are measuring and it averages out after a few cycles. You might try a 60Hz RC filter to remove noise but I think to do any better you will have to treat the signal as if it were audio frequency. So scale it to 1 volt peak to peak and read it with an audio interface and then use an FFT. But the transformer on the DCD pin of any normal computer with the Linux PPS driver works. People are doing just fine with the simple transformer and time stamping the transitions. And then it is just pure luck that Linux will already do this out of the box. On Sun, Feb 9, 2014 at 5:53 AM, M. Simon msimon6...@yahoo.com wrote: This probably came up during the recent discussion of Line Frequency Monitoring but I may have missed it. Does any one have a circuit (tested - operational) for monitoring line frequency? I'd like something that checks zero crossing so that it is relatively insensitive to line voltage variations. Simon Engineering is the art of making what you want from what you can get at a profit. ___ 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] Line Frequency
All you need to monitor line frequency is a small transformer connected to a computer's DCD pin on a serial port. You can get fancier and use comparator, opto isolation and so on but a simple 5V transformer is enough. This takes advantage of the electronics inside the RS232 port that is designed to handle positive and negative voltages up to about +/- 12 volts. Then the linux pulse per second driver will time stamp and log every cycle with the internal clock. It is accurate to a couple microseconds. Don't worry about line noise because that is what you are measuring and it averages out after a few cycles. You might try a 60Hz RC filter to remove noise but I think to do any better you will have to treat the signal as if it were audio frequency. So scale it to 1 volt peak to peak and read it with an audio interface and then use an FFT. But the transformer on the DCD pin of any normal computer with the Linux PPS driver works. People are doing just fine with the simple transformer and time stamping the transitions. And then it is just pure luck that Linux will already do this out of the box. On Sun, Feb 9, 2014 at 5:53 AM, M. Simon msimon6...@yahoo.com wrote: This probably came up during the recent discussion of Line Frequency Monitoring but I may have missed it. Does any one have a circuit (tested - operational) for monitoring line frequency? I'd like something that checks zero crossing so that it is relatively insensitive to line voltage variations. Simon Engineering is the art of making what you want from what you can get at a profit. ___ 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] Line Frequency
msimon6...@yahoo.com said: Does any one have a circuit (tested - operational) for monitoring line frequency? I'd like something that checks zero crossing so that it is relatively insensitive to line voltage variations. I'm assuming you are starting with an AC wall wart and 2 resistors to divide the voltage down to something within range. The easy to understand way is to use 2 more resistors to bias your input pin at the switching threshold and a cap to connect the middle of both pairs. The circuit would look like a H with 4 resistors on the vertical bars of the H and a cap on the horizontal bar. Top left of H connected to AC in, top right to +V, bottom left and bottom right to ground, and center right to input pin. You can do it with 3 resistors. Replace the lower of the 2 resistor setup with a pair, one to ground and the other to +V. Adjust the size of those resistors so the parallel resistance is the same as the one you are replacing and the middle voltage is the switching point. Mumble. There is a word for this that I can't remember. It's used for things like terminating ECL input signals. If you are going in to a RS-232 port, you can probably get a useful +V from one of the modem control signals. I forget the polarity. You may have to hack your software to set it to the right polarity. -- 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] How I got my FE-5680A to lock in Sydney, Australia
Hi Mark, I doubt if the counter is off frequency, since I'm using the 1pps pulses from my GPSDO as its timebase. So although there's a bit of short-term jitter, the longer-term count should be very close. I will try the experiment you suggest, though, and see what difference inversion makes to the frequency swing before locking (or non-locking). Thanks, -Original Message- From: Mark Sims Sent: Sunday, February 09, 2014 4:37 PM To: time-nuts@febo.com Subject: [time-nuts] How I got my FE-5680A to lock in Sydney, Australia What was the timebase for your counter? I suspect that it is off freq and the Rb is not actually making it above 10 MHz. Inverting the Rb is causing a 2G shift in gravity to the Rb crystal probably shifting its freq enough to cause lock. ___ 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] BC637PCI 1024 week rollover
In a message dated 09/02/2014 15:31:47 GMT Standard Time, mag...@rubidium.dyndns.org writes: On 09/02/14 12:56, gandal...@aol.com wrote: Oh well, full credit to Mr Trimble for getting it right, he does bake exceedingly nice GPS modules and the Ace3 doesn't have a rollover issue and it does report the date correctly. Unfortunately, as far as I can tell anyway, the BC637PCI takes the raw GPS time data from the Ace3 and performs its own calculation which is where the problem seems to occur, certainly it's a 1024 week issue with the date from the BC637 being displayed as June 26 1994 in all versions of the associated demo software. It is possible to set the date correctly but the next packet from the GPS module promptly overwrites it again. I still don't recall seeing this before, although with two boards behaving in the same fashion I'm having doubts about that, but more to the point these boards indicate a firmware date of 2003 which implies they were put into the field like this, and that doesn't make much sense either. Any ideas anyone?, and again has anyone else seen this and/or am I missing something glaringly obvious? If the ACE3 gives correct date, but the BC637 FW does not, then it is obvious that the FW does the unwrapping itself just like a problematic GPS receiver would. Most probably would the ACE3 have issues if it looses it's CMOS backup. I haven't looked at those details, but you should be able to disable the date from being set by the GPS. Maybe play around there. Might be that the FW needs an update, which naturally may not be in existence. Can you read-out the EPROM? Only proves to show that my comment that NTPD needs to do the 1024 week correction for other GPS dependent drivers than the NMEA (NTP bug 2466) is a correct assumption. See the posting I forwarded yesterday. Cheers, Magnus Hi Magnus, and thanks for your comments. I arrived at the same conclusion regarding the BC637 firmware and that's the issue I'd like to resolve, but I'm a bit cautious given that these were produced after 1999 as I can't understand why the firmware wouldn't already have been updated. It is possible to set the board for other than GPS, (Timecode, Freerunning, or 1PPS) but I suspect I might then loose the conditioning, something I'd need to check. Either way, I'd like to have the correct GPS date too if possible, but it's the conditioning that's of more interest so I'd do without the correct date if needs be. I've identified two programmable devices, the version H manual with schematics is very useful:-), the first being a OTP configuration PROM for the Spartan FPGA and the other a TMS29F010 flash mamory IC which I suspect holds the firmware. That is socketed but I don't think I have the necessary 32 pin quad adapter to be able to read it. This was only intended to be a quick test, funny how quick tests soon become major projects:-), so these might have to go back into hibernation again shortly, for the time being at least. Regards Nigel ___ 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] BC637PCI 1024 week rollover
It may be that your onboard batteries are in better health than mine are, although mine might have been disabled using the software, as I tried booting up without an antenna this evening and got the right year this time but twith he date as 1st January:-) What I found when running in GPS mode was that I could correct the date but it would get overwritten again. As I commented in my previous reply to Magnus' comments, I still don't understand why units produced after 1999 should have this problem anyway. Thanks for the data, I'll keep that and compare later, and I'll be very interested to hear how yours performs once the antennna is connected. Running off 1PPS is an option but I'd much prefer to use actual GPS time if possible, unfortunately, as commented earlier, the problem lies with the BC637 itself, not the GPS module. Your mention of other GPS modules reminds me that the appropriate set of schematics for these BC637s shows that a header swap would allow the board to use a Motorola Oncore in place of the Trimble ACE2 or ACE3. Not sure that I'll ever try that but it might help explain why they take the raw GPS data rather than what's already been processed by the module. Regards Nigel In a message dated 09/02/2014 15:34:22 GMT Standard Time, t...@patoka.org writes: Hello, I'll be glad to check my GPS module to see what is going on there, however I am still waiting for the GPS antenna to be delivered. I tried to use some small form factor Trimple GPS antenna with BC637, but on-board GPS module couldn't lock with it. So, my BC637 is working in freerun mode now: Time Settings: Mode : Free Run Time Format : Binary Year : 2014 Local Offset : 0.0 Propagation Delay : 0 Current Leap Seconds : 0 Scheduled Leap Event Time : 1391731200 Scheduled Leap Event Flag : Insertion GPS Time Format : UTC Format IEEE Daylight Savings Flag : Enable I have no issues with date stamp in that mode: Binary Time: 02/09/2014 14:36:19.7005289 Status: 0 Binary Time: 02/09/2014 14:36:19.7105941 Status: 0 Binary Time: 02/09/2014 14:36:19.7206589 Status: 0 Even if I switch BC637 to GPS mode, it still using correct date. Which is expected, because in accordance with documents, if GPS is not locked, BC637 will behave in the same way as free run. The difference is the Status. Its shows, four bits. And one of them indicates that GPS is not locked: Binary Time: 02/09/2014 14:37:43.0045326 Status: 7 Binary Time: 02/09/2014 14:37:43.0146051 Status: 7 Binary Time: 02/09/2014 14:37:43.0246776 Status: 7 As soon as I'll get my bullet GPS antena attached, I'll see what is going on there for the date stamp. Also, in the documents, I saw some sections, which explain how to use data registers to send some command to Trimble GPS. Probably its is possible to do some corrections through that procedure. May be it is possible to attach another GPS module to the BC637 card. Its using 9 pin connector. This connector is used primarily for connecting the ACE III GPS. Data communications between the board and the GPS receiver are via serial signals. Additionally, the GPS receiver provides a 1 PPS signal to the board. Regards, V.P. On 2014-02-09 06:56, gandal...@aol.com wrote: Oh well, full credit to Mr Trimble for getting it right, he does bake exceedingly nice GPS modules and the Ace3 doesn't have a rollover issue and it does report the date correctly. Unfortunately, as far as I can tell anyway, the BC637PCI takes the raw GPS time data from the Ace3 and performs its own calculation which is where the problem seems to occur, certainly it's a 1024 week issue with the date from the BC637 being displayed as June 26 1994 in all versions of the associated demo software. It is possible to set the date correctly but the next packet from the GPS module promptly overwrites it again. I still don't recall seeing this before, although with two boards behaving in the same fashion I'm having doubts about that, but more to the point these boards indicate a firmware date of 2003 which implies they were put into the field like this, and that doesn't make much sense either. Any ideas anyone?, and again has anyone else seen this and/or am I missing something glaringly obvious? Regards Nigel GM8PZR ___ 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. -- WBW, V.P. ___ 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] Fw: Rb as source for ADEV?
Hi Orin, No, it's not a matter of just talking to the device. I can to that. The problem happens when you want more than one program/process to access the GPIB bus at the same time; e.g. running two different tests. For that you have to have a server process which manages the interface and relays packets to the clients. Prologix hadn't written one when they commented here last summer. Bob From: Orin Eman orin.e...@gmail.com To: Bob Stewart b...@evoria.net; Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sunday, February 9, 2014 12:55 PM Subject: Re: [time-nuts] Rb as source for ADEV? Bob, If you want a C++ class to talk to the Prologix Ethernet, I have one. (I don't have a USB version, but that would just be a matter of implementing a simple subclass to do the communication with the device.) I also have code that uses the above and talk to a 5335A and to a 5370A, both of which like to sulk if you don't do things in the right order. It's written for Windows and should compile in the _free_ Visual Studio Express 2012 (it used to, but the last time I built it was with the full version). Porting to Linux/Mac/iOS would be easy enough... maybe I'll do iOS for fun, if Xcode doesn't sulk and stays alive long enough that is; the only thing Xcode does fast for me is crash! Licensing for all but the findAdapters method will be LGPL once I put headers in. findAdapters() is derived from John Miles's GPIB library and subject to its licensing. ___ 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] How I got my FE-5680A to lock in Sydney, Australia
Hi Magnus, Thanks for your further comments. As you probably saw in my reply to Mark Sims, I am proposing to check the swing limits 'before and after' inverting the unit, to check out the theory before I open it up and try tweaking C217. Cheers, Jim -Original Message- From: Magnus Danielson Sent: Sunday, February 09, 2014 7:34 PM To: time-nuts@febo.com Subject: Re: [time-nuts] How I got my FE-5680A to lock in Sydney, Australia On 09/02/14 02:57, Jamieson (Jim) Rowe wrote: Hi Magnus, Thanks again for those further suggestions. I do have a GPSDO, and I had been able to use it with a counter to check that the FE-5680A was swinging either side of 10MHz. But I didn't make sure that it was swinging evenly each side of 10MHz . According to my notes it was swinging between 9.999770 and 10.36MHz -- i.e., about 230Hz low and about 36Hz high. But it was spending more of the time below 10MHz than above -- does this suggest to you that I should tweak C217 until it swings by about the same amount either way? Yes, that is exactly what I would do. 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 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] Line Frequency
It depends of your goals. If you want a 60 Hz time/frequency standard then using a mains disciplined oscillator is good. Like AN12 shows. But if your goal is to measure mains itself, warts and all, then measure mains as it is, not a pure oscillator tied to mains by PLL or FLL. See this Atmel app note: http://www.atmel.com/images/doc2508.pdf Also: http://leapsecond.com/pages/ac-detect/ /tvb (i5s) On Feb 9, 2014, at 12:04 PM, M. Simon msimon6...@yahoo.com wrote: I kind of like the synchronized oscillator on page 6 of this pdf http://cds.linear.com/docs/en/application-note/an12fa.pdf They claim good results. I may have to build one and see. Engineering is the art of making what you want from what you can get at a profit. On Sunday, February 9, 2014 7:44 PM, Chris Albertson albertson.ch...@gmail.com wrote: All you need to monitor line frequency is a small transformer connected to a computer's DCD pin on a serial port. You can get fancier and use comparator, opto isolation and so on but a simple 5V transformer is enough. This takes advantage of the electronics inside the RS232 port that is designed to handle positive and negative voltages up to about +/- 12 volts. Then the linux pulse per second driver will time stamp and log every cycle with the internal clock. It is accurate to a couple microseconds. Don't worry about line noise because that is what you are measuring and it averages out after a few cycles. You might try a 60Hz RC filter to remove noise but I think to do any better you will have to treat the signal as if it were audio frequency. So scale it to 1 volt peak to peak and read it with an audio interface and then use an FFT. But the transformer on the DCD pin of any normal computer with the Linux PPS driver works. People are doing just fine with the simple transformer and time stamping the transitions. And then it is just pure luck that Linux will already do this out of the box. On Sun, Feb 9, 2014 at 5:53 AM, M. Simon msimon6...@yahoo.com wrote: This probably came up during the recent discussion of Line Frequency Monitoring but I may have missed it. Does any one have a circuit (tested - operational) for monitoring line frequency? I'd like something that checks zero crossing so that it is relatively insensitive to line voltage variations. Simon Engineering is the art of making what you want from what you can get at a profit. ___ 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. ___ 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] BC637PCI 1024 week rollover
I found the document about Trimble ACE3 module: http://www.symres.com/files/ACE3.pdf Here is the paragraph about WNRO: Effect of GPS Week Number Roll-over (WNRO) The ACE III GPS module has been designed to handle WNRO, and there are no problems with either dates or first fix after WNRO through the year 2015. [* Note – GPS Week Numbers system, as defined by the ICD200 GPS Specification, occupy a range from zero to 1023. The Week Number Roll Over (WNRO) occurs every 1024 weeks, or approximately every 19 years 8 months. August 1999 was the first roll-over for the GPS system since the beginning of GPS time on 06 January 1980.] [ Caution – Trimble OEM GPS receivers have reported the true GPS Week Number in TSIP messages 0x41 and 0x8F-20 as a number between 0 and 1023. The ACE III GPS outputs the Extended GPS Week Number as the absolute number of weeks since the beginning of GPS time or 06 January 1980. If the true GPS Week Number is desired, the system developer should ignore the extra MSBs of the Extended GPS Week Number and use only the 10 LSBs] I tried to modify the demo code to obtain FW of my GPS module. But I had no luck with it, since bcGPSMan subroutine always return ERROR state in response to packet ID 0x1F. Regards, V.P. On 2014-02-09 16:05, gandal...@aol.com wrote: In a message dated 09/02/2014 15:31:47 GMT Standard Time, mag...@rubidium.dyndns.org writes: On 09/02/14 12:56, gandal...@aol.com wrote: Oh well, full credit to Mr Trimble for getting it right, he does bake exceedingly nice GPS modules and the Ace3 doesn't have a rollover issue and it does report the date correctly. Unfortunately, as far as I can tell anyway, the BC637PCI takes the raw GPS time data from the Ace3 and performs its own calculation which is where the problem seems to occur, certainly it's a 1024 week issue with the date from the BC637 being displayed as June 26 1994 in all versions of the associated demo software. It is possible to set the date correctly but the next packet from the GPS module promptly overwrites it again. I still don't recall seeing this before, although with two boards behaving in the same fashion I'm having doubts about that, but more to the point these boards indicate a firmware date of 2003 which implies they were put into the field like this, and that doesn't make much sense either. Any ideas anyone?, and again has anyone else seen this and/or am I missing something glaringly obvious? If the ACE3 gives correct date, but the BC637 FW does not, then it is obvious that the FW does the unwrapping itself just like a problematic GPS receiver would. Most probably would the ACE3 have issues if it looses it's CMOS backup. I haven't looked at those details, but you should be able to disable the date from being set by the GPS. Maybe play around there. Might be that the FW needs an update, which naturally may not be in existence. Can you read-out the EPROM? Only proves to show that my comment that NTPD needs to do the 1024 week correction for other GPS dependent drivers than the NMEA (NTP bug 2466) is a correct assumption. See the posting I forwarded yesterday. Cheers, Magnus Hi Magnus, and thanks for your comments. I arrived at the same conclusion regarding the BC637 firmware and that's the issue I'd like to resolve, but I'm a bit cautious given that these were produced after 1999 as I can't understand why the firmware wouldn't already have been updated. It is possible to set the board for other than GPS, (Timecode, Freerunning, or 1PPS) but I suspect I might then loose the conditioning, something I'd need to check. Either way, I'd like to have the correct GPS date too if possible, but it's the conditioning that's of more interest so I'd do without the correct date if needs be. I've identified two programmable devices, the version H manual with schematics is very useful:-), the first being a OTP configuration PROM for the Spartan FPGA and the other a TMS29F010 flash mamory IC which I suspect holds the firmware. That is socketed but I don't think I have the necessary 32 pin quad adapter to be able to read it. This was only intended to be a quick test, funny how quick tests soon become major projects:-), so these might have to go back into hibernation again shortly, for the time being at least. Regards Nigel ___ 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. -- WBW, V.P. ___ 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] Line Frequency
Hal, The resistor H bridge with a capacitor in between sounds like a good idea. Yes - I'm starting with a wall wart. About 12 VAC. Maybe a couple of back to back diodes (zeners?) across the capacitor to make sure the voltage stays in the input range of the op amp/comparator. I like the LT1122 for speed. It is not too pricey. But there is always the ubiquitous LM111 family. I do get the ECL biasing trick you pointed out. Chris, Experimenting is good. Except that to do a valid test I'd have to run the experiments in parallel. I'm not just using this for triac triggering. I want to take measurements in real time. i.e. a PC running an FFT will not get me what I want. I may ultimately have to create a test set that generates 60.000 Hz and injects a noise signal ( +/- .1V pulses at 100 KHz say) that can be turned off. The 60 Hz need not be extremely accurate. Just stable. My counter does time triggering so I can do averaging if necessary without the counter swallowing pulses. Simon Engineering is the art of making what you want from what you can get at a profit. On Sunday, February 9, 2014 8:38 PM, Hal Murray hmur...@megapathdsl.net wrote: msimon6...@yahoo.com said: Does any one have a circuit (tested - operational) for monitoring line frequency? I'd like something that checks zero crossing so that it is relatively insensitive to line voltage variations. I'm assuming you are starting with an AC wall wart and 2 resistors to divide the voltage down to something within range. The easy to understand way is to use 2 more resistors to bias your input pin at the switching threshold and a cap to connect the middle of both pairs. The circuit would look like a H with 4 resistors on the vertical bars of the H and a cap on the horizontal bar. Top left of H connected to AC in, top right to +V, bottom left and bottom right to ground, and center right to input pin. You can do it with 3 resistors. Replace the lower of the 2 resistor setup with a pair, one to ground and the other to +V. Adjust the size of those resistors so the parallel resistance is the same as the one you are replacing and the middle voltage is the switching point. Mumble. There is a word for this that I can't remember. It's used for things like terminating ECL input signals. If you are going in to a RS-232 port, you can probably get a useful +V from one of the modem control signals. I forget the polarity. You may have to hack your software to set it to the right polarity. -- 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] BC637PCI 1024 week rollover
On 09/02/14 22:05, gandal...@aol.com wrote: In a message dated 09/02/2014 15:31:47 GMT Standard Time, mag...@rubidium.dyndns.org writes: On 09/02/14 12:56, gandal...@aol.com wrote: Oh well, full credit to Mr Trimble for getting it right, he does bake exceedingly nice GPS modules and the Ace3 doesn't have a rollover issue and it does report the date correctly. Unfortunately, as far as I can tell anyway, the BC637PCI takes the raw GPS time data from the Ace3 and performs its own calculation which is where the problem seems to occur, certainly it's a 1024 week issue with the date from the BC637 being displayed as June 26 1994 in all versions of the associated demo software. It is possible to set the date correctly but the next packet from the GPS module promptly overwrites it again. I still don't recall seeing this before, although with two boards behaving in the same fashion I'm having doubts about that, but more to the point these boards indicate a firmware date of 2003 which implies they were put into the field like this, and that doesn't make much sense either. Any ideas anyone?, and again has anyone else seen this and/or am I missing something glaringly obvious? If the ACE3 gives correct date, but the BC637 FW does not, then it is obvious that the FW does the unwrapping itself just like a problematic GPS receiver would. Most probably would the ACE3 have issues if it looses it's CMOS backup. I haven't looked at those details, but you should be able to disable the date from being set by the GPS. Maybe play around there. Might be that the FW needs an update, which naturally may not be in existence. Can you read-out the EPROM? Only proves to show that my comment that NTPD needs to do the 1024 week correction for other GPS dependent drivers than the NMEA (NTP bug 2466) is a correct assumption. See the posting I forwarded yesterday. Cheers, Magnus Hi Magnus, and thanks for your comments. I arrived at the same conclusion regarding the BC637 firmware and that's the issue I'd like to resolve, but I'm a bit cautious given that these were produced after 1999 as I can't understand why the firmware wouldn't already have been updated.' It probably operates on a shifted 1024 week period and that was probably not changed after the original code was written. Obviously the shifted wrapping has now occurred. 1999 is only relevant for the non-shifted 1024 period. It is possible to set the board for other than GPS, (Timecode, Freerunning, or 1PPS) but I suspect I might then loose the conditioning, something I'd need to check. Either way, I'd like to have the correct GPS date too if possible, but it's the conditioning that's of more interest so I'd do without the correct date if needs be. I've identified two programmable devices, the version H manual with schematics is very useful:-), the first being a OTP configuration PROM for the Spartan FPGA and the other a TMS29F010 flash mamory IC which I suspect holds the firmware. That is socketed but I don't think I have the necessary 32 pin quad adapter to be able to read it. It would be the TMS29F010 flash which would be of interest. This was only intended to be a quick test, funny how quick tests soon become major projects:-), so these might have to go back into hibernation again shortly, for the time being at least. Fair enough! 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] Rb as source for ADEV?
Hi If both / all of the counters are collecting 1 second data, the GPIB stuff isn’t going to be to bad … There’s always an If. You need to run the counters so they do it all automatically (arm etc). That’s the way it’s normally done It should not be to big a constraint. The rest of it turns into a poll this poll that loop. When one of the counters has data you grab it and shove it into a file someplace. The counters buffer the data, so they only get bothered if the poll / read process gets to a significant fraction of a second. They started out doing HPIB / GPIB with some *very* slow hardware. The 5335 and 5334 date to that era. They have been fully debugged with gear that waits a while to grab data from them. If you are running a lot faster then yes… you can get into issues. Bob On Feb 9, 2014, at 4:28 PM, Bob Stewart b...@evoria.net wrote: Hi Orin, No, it's not a matter of just talking to the device. I can to that. The problem happens when you want more than one program/process to access the GPIB bus at the same time; e.g. running two different tests. For that you have to have a server process which manages the interface and relays packets to the clients. Prologix hadn't written one when they commented here last summer. Bob From: Orin Eman orin.e...@gmail.com To: Bob Stewart b...@evoria.net; Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sunday, February 9, 2014 12:55 PM Subject: Re: [time-nuts] Rb as source for ADEV? Bob, If you want a C++ class to talk to the Prologix Ethernet, I have one. (I don't have a USB version, but that would just be a matter of implementing a simple subclass to do the communication with the device.) I also have code that uses the above and talk to a 5335A and to a 5370A, both of which like to sulk if you don't do things in the right order. It's written for Windows and should compile in the _free_ Visual Studio Express 2012 (it used to, but the last time I built it was with the full version). Porting to Linux/Mac/iOS would be easy enough... maybe I'll do iOS for fun, if Xcode doesn't sulk and stays alive long enough that is; the only thing Xcode does fast for me is crash! Licensing for all but the findAdapters method will be LGPL once I put headers in. findAdapters() is derived from John Miles's GPIB library and subject to its licensing. ___ 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] Line Frequency
Tom, I was hoping for 1E-5 precision or better. My time stamping counter will have a 30 MHz clock (for convenience). My initial experiments will just set the 30 MHz clock to within about .1 ppm and ultimately I will sync it with GPS so I can track phase long term. In fact for quick, dirty, and cheap I will probably use a 10 ppm packaged oscillator with no adjustment. The ones I have checked out so far seem to be about +/- 2 ppm or so at room temperature. I like your idea (well you made me think of it) of filtering with time stamps. Only stamps within +/- 1 Hz of the line frequency are accepted (or what ever seems reasonable given grid limits). I would probably need a loss of line voltage circuit in addition. That is not a drawback. But loss of line voltage might be done in software as well. Simon Date: Sun, 9 Feb 2014 11:53:04 -0800 From: Tom Van Baak (lab) t...@leapsecond.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Line Frequency Message-ID: 475bacc5-deef-43b7-a8ce-6416d997f...@leapsecond.com Content-Type: text/plain; charset=us-ascii Hi Simon, 1) You can use the picPET to measure zero crossings; just bias the input. 2) With no external parts at all the picPET is a 2.5V crossing detector. 3) What you find when you start playing with 60 Hz is that this is not a problem. That's why few/none of us bother with it. 4) The time of 60 Hz varies so much minute to minute or hour to hour that line voltage effects are mostly irrelevant. 5) The picPET input is pin5, which is a Schmitt trigger input. 6) Schmitt trigger or not, line noise is no problem for a time-stamping counter anyway. What level of precision are you after? /tvb (i5s) On Feb 9, 2014, at 8:04 AM, M. Simon msimon6...@yahoo.com wrote: Bill, I was hoping to avoid a device that was dependent on line voltage (rather than zero crossings) for timing as it will then be line voltage sensitive (or at least more than a zero crossing detector). Of course zero voltage (zero crossing) detectors have other problems. Susceptibility to line noise being one major one. Simon Engineering is the art of making what you want from what you can get at a profit. ___ 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] Line Frequency
This one is very good, i have assembled it myself: http://www.dextrel.net/diyzerocrosser.htm Works very well with a very big voltage range, and it´s isolated. Only disadvantage is that it generates 120Hz output, but I think you can easily change that (turning the bridge rectifier into a half-wave rectifier). Daniel Em 09/02/2014 19:34, Tom Van Baak (lab) escreveu: It depends of your goals. If you want a 60 Hz time/frequency standard then using a mains disciplined oscillator is good. Like AN12 shows. But if your goal is to measure mains itself, warts and all, then measure mains as it is, not a pure oscillator tied to mains by PLL or FLL. See this Atmel app note: http://www.atmel.com/images/doc2508.pdf Also: http://leapsecond.com/pages/ac-detect/ /tvb (i5s) On Feb 9, 2014, at 12:04 PM, M. Simon msimon6...@yahoo.com wrote: I kind of like the synchronized oscillator on page 6 of this pdf http://cds.linear.com/docs/en/application-note/an12fa.pdf They claim good results. I may have to build one and see. Engineering is the art of making what you want from what you can get at a profit. On Sunday, February 9, 2014 7:44 PM, Chris Albertson albertson.ch...@gmail.com wrote: All you need to monitor line frequency is a small transformer connected to a computer's DCD pin on a serial port. You can get fancier and use comparator, opto isolation and so on but a simple 5V transformer is enough. This takes advantage of the electronics inside the RS232 port that is designed to handle positive and negative voltages up to about +/- 12 volts. Then the linux pulse per second driver will time stamp and log every cycle with the internal clock. It is accurate to a couple microseconds. Don't worry about line noise because that is what you are measuring and it averages out after a few cycles. You might try a 60Hz RC filter to remove noise but I think to do any better you will have to treat the signal as if it were audio frequency. So scale it to 1 volt peak to peak and read it with an audio interface and then use an FFT. But the transformer on the DCD pin of any normal computer with the Linux PPS driver works. People are doing just fine with the simple transformer and time stamping the transitions. And then it is just pure luck that Linux will already do this out of the box. On Sun, Feb 9, 2014 at 5:53 AM, M. Simon msimon6...@yahoo.com wrote: This probably came up during the recent discussion of Line Frequency Monitoring but I may have missed it. Does any one have a circuit (tested - operational) for monitoring line frequency? I'd like something that checks zero crossing so that it is relatively insensitive to line voltage variations. Simon Engineering is the art of making what you want from what you can get at a profit. ___ 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. ___ 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] BC637PCI 1024 week rollover
On 09/02/14 23:24, d0ct0r wrote: I found the document about Trimble ACE3 module: http://www.symres.com/files/ACE3.pdf Here is the paragraph about WNRO: Effect of GPS Week Number Roll-over (WNRO) The ACE III GPS module has been designed to handle WNRO, and there are no problems with either dates or first fix after WNRO through the year 2015. [* Note – GPS Week Numbers system, as defined by the ICD200 GPS Specification, occupy a range from zero to 1023. The Week Number Roll Over (WNRO) occurs every 1024 weeks, or approximately every 19 years 8 months. August 1999 was the first roll-over for the GPS system since the beginning of GPS time on 06 January 1980.] First GPS week of 2016 is GPS week of 1878. Which gives indication wrap-around and also means it has been valid since mid 1996. [ Caution – Trimble OEM GPS receivers have reported the true GPS Week Number in TSIP messages 0x41 and 0x8F-20 as a number between 0 and 1023. The ACE III GPS outputs the Extended GPS Week Number as the absolute number of weeks since the beginning of GPS time or 06 January 1980. If the true GPS Week Number is desired, the system developer should ignore the extra MSBs of the Extended GPS Week Number and use only the 10 LSBs] If you don't listen to the Extended GPS Week Number, you are toast, but as there is an end to the Ace III extension capability, there isn't far away and you are toast anyway. I tried to modify the demo code to obtain FW of my GPS module. But I had no luck with it, since bcGPSMan subroutine always return ERROR state in response to packet ID 0x1F. I think this is another case where the developers didn't forsee this situation. 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] Line Frequency
On Sun, Feb 9, 2014 at 3:11 PM, M. Simon msimon6...@yahoo.com wrote: Hal, The resistor H bridge with a capacitor in between sounds like a good idea. Yes - I'm starting with a wall wart. About 12 VAC. Maybe a couple of back to back diodes (zeners?) The normal clamp design uses two normal diodes both pointing the same direction and in series. Theses span the power supply rails. Of course they are installed in the direction where they do not normally conduct. Your signal goes to the point where the two diodes connect. No Zeners. The 1N4000 series or anything like it would be fine. If the signal goes higher than the higher voltage rail then the diode that connects to that rail will conduct. A resister in series with the input signal will limit current to what the diode can handle. Knowing that you can limit current, a smaller (and faster) switching diode made be used. I use this diode clamp setup an an Anemometer that produces AC current with frequency proportional to wind speed. The diodes clamp the voltage (which can get up to 12V i a storm) just fine. I'm using a cheap lm311. But if this is feeding an RS232 port, the port is designed to handle about +/- 12 volts so you'd only be protecting from shorts and other accidents. Zeners are good for lightening protection. So are MOVs and you might want these on anything connected to mains power but in your application I'd just use a handily spike bar aka surge protector. -- 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] How I got my FE-5680A to lock in Sydney, Australia
Hi again Magnus, Mark, Tom Harris, Ed Palmer et al, Well, before performing any surgery on my tricky little beasty, I decided to check its frequency swing limits when starting up in the 'inverted' position, and then when starting up in the right-side-up position. Here's what I found, as before looking at the frequency with my counter (GPSDXO 1pps timebase): Inverted position: swings between 9,999,798Hz and 10,000,001Hz, before locking. Normal position: swings between 9,999,756Hz and 10,000,057Hz, a few times. But wait for it -- it then locked up, reliably, in the right-side-up position! So now I'm really confused. It looks as if whatever was wrong with it before has somehow fixed itself, after running it for a couple of days locked in the inverted position... Anyway, I think I'll leave opening it up for a while (at least) -- since it's now running locked fine in the right-side-up position. I don't want to tempt fate, while its OK. What's that old adage? If it ain't broke, don't try to fix it. Cheers all, Jim Rowe -Original Message- From: Jamieson (Jim) Rowe Sent: Monday, February 10, 2014 8:05 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] How I got my FE-5680A to lock in Sydney, Australia Hi Magnus, Thanks for your further comments. As you probably saw in my reply to Mark Sims, I am proposing to check the swing limits 'before and after' inverting the unit, to check out the theory before I open it up and try tweaking C217. Cheers, Jim -Original Message- From: Magnus Danielson Sent: Sunday, February 09, 2014 7:34 PM To: time-nuts@febo.com Subject: Re: [time-nuts] How I got my FE-5680A to lock in Sydney, Australia On 09/02/14 02:57, Jamieson (Jim) Rowe wrote: Hi Magnus, Thanks again for those further suggestions. I do have a GPSDO, and I had been able to use it with a counter to check that the FE-5680A was swinging either side of 10MHz. But I didn't make sure that it was swinging evenly each side of 10MHz . According to my notes it was swinging between 9.999770 and 10.36MHz -- i.e., about 230Hz low and about 36Hz high. But it was spending more of the time below 10MHz than above -- does this suggest to you that I should tweak C217 until it swings by about the same amount either way? Yes, that is exactly what I would do. 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 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] Line Frequency
Simon, Good, you decided to make a time stamping counter instead of a frequency counter then? On your spec -- 1e-5 precision of what? Of time accuracy? Or frequency accuracy? And over what time frame? The power line will give you 1e-5 stability at one second intervals; but this precision is destroyed as you average longer and longer (due to the rather significant variation in frequency that occurs in the grid). By one minute or one hour it's 1e-4. It takes a couple of days of averaging to get back down to 1e-5 precision. The way to see this is with an ADEV of the power line frequency: http://leapsecond.com/pages/mains/mains-picpet-23.gif I'm not sure about your +/- 1 Hz filtering suggestion. I don't do that here. But maybe your use for mains is different from mine. Do you want to use the power line as a reference time to slowly steer a drifting quartz oscillator over a month or year? Or do you want to make measurements of power line phase and frequency to make pretty real-time plots like Hal and I and others do? /tvb - Original Message - From: M. Simon To: time-nuts@febo.com ; t...@leapsecond.com Sent: Sunday, February 09, 2014 4:27 PM Subject: Re: [time-nuts] Line Frequency Tom, I was hoping for 1E-5 precision or better. My time stamping counter will have a 30 MHz clock (for convenience). My initial experiments will just set the 30 MHz clock to within about .1 ppm and ultimately I will sync it with GPS so I can track phase long term. In fact for quick, dirty, and cheap I will probably use a 10 ppm packaged oscillator with no adjustment. The ones I have checked out so far seem to be about +/- 2 ppm or so at room temperature. I like your idea (well you made me think of it) of filtering with time stamps. Only stamps within +/- 1 Hz of the line frequency are accepted (or what ever seems reasonable given grid limits). I would probably need a loss of line voltage circuit in addition. That is not a drawback. But loss of line voltage might be done in software as well. Simon Date: Sun, 9 Feb 2014 11:53:04 -0800 From: Tom Van Baak (lab) t...@leapsecond.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Line Frequency Message-ID: 475bacc5-deef-43b7-a8ce-6416d997f...@leapsecond.com Content-Type: text/plain;Charest=us-ASCII Hi Simon, 1) You can use the picPET to measure zero crossings; just bias the input. 2) With no external parts at all the picPET is a 2.5V crossing detector. 3) What you find when you start playing with 60 Hz is that this is not a problem. That's why few/none of us bother with it. 4) The time of 60 Hz varies so much minute to minute or hour to hour that line voltage effects are mostly irrelevant. 5) The picPET input is pin5, which is a Schmitt trigger input. 6) Schmitt trigger or not, line noise is no problem for a time-stamping counter anyway. What level of precision are you after? /tvb (i5s) On Feb 9, 2014, at 8:04 AM, M. Simon msimon6...@yahoo.com wrote: Bill, I was hoping to avoid a device that was dependent on line voltage (rather than zero crossings) for timing as it will then be line voltage sensitive (or at least more than a zero crossing detector). Of course zero voltage (zero crossing) detectors have other problems. Susceptibility to line noise being one major one. Simon ___ 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] Line Frequency
Maybe a couple of back to back diodes (zeners?) across the capacitor to make sure the voltage stays in the input range of the op amp/comparator. The standard approach in the digital world is Schottky diodes. They come with a pair in a tiny 3 pin package. Most digital logic has built-in protection diodes. Look at the fine print in the data sheets. There is usually a max current and/or max voltage/time/area spec. It may be off in the general info sheet for the logic family. It's common to take advantage of those diodes by using a current limiting resistor. I like the LT1122 for speed. It is not too pricey. But there is always the ubiquitous LM111 family. I'm missing the big picture. Why are you adding another chip? What are you going to connect this signal to? As tvb has shown, you can connect the AC line directly to a PIC input pin with a big enough current limiting resistor. I'm using an AC wall wart and a pair of resistors to get within range of the modem control signals. I've had no noise events in the past 50 days. I did have noise problems with boxes running off an isolated power brick. I never tracked it down. I assume it was a missing green wire ground so the chassis ground jumped around when interesting stuff came in over the power line. -- You can feed the signal into the audio input and capture the raw data and look for glitches. -- 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] GPS W/10KHz
On 8 Feb, 2014, at 14:50 , ewkeh...@aol.com wrote: The problem with the PLL analog version is the same as with any digital GPSDO. The saw tooth is present at 10 KHz just like 1 Hz. To the best of my knowledge there is no GPS receivers out there for less than $ 1000 with out saw tooth. Timing receivers output the correction value and you can either with software or a variable delay do correction. This is very true, though the sawtooth at a 10 kpps sample rate is going to a little different than the sawtooth at a 1 pps sample rate. The frequency of the sawtooth noise will lie somewhere in the Nyquist bandwidth. At a 1 pps sample rate the frequency of the sawtooth noise will hence be somewhere between 0 Hz and 0.5 Hz, while at 10 kpps the sawtooth frequency will range from 0 Hz to 5 kHz. Noise at less than 0.5 Hz is not easy to filter, so you are going to require the correction from the receiver and/or an integrator with a time constant that can only be realized digitally. Sawtooth noise over most of a 0 Hz to 5 kHz range, on the other hand, should be eliminated by the analog low pass filter after the phase detector in the PLL, giving you something nice and clean coming out. It is only if you get unlucky and the beat frequency between GPS time and the receiver's oscillator ends up very close to an integer multiple of 10 kHz that you'll see noise at a low enough frequency to leak through into the control response. This is interesting because it suggests that very simple GPSDOs using 10 kHz from the receiver might at times work worse than you are likely to observe in a single bench measurement as aging (or something) moves the receiver's oscillator frequency through one of the bad frequency errors. Or is there a way to avoid that altogether (maybe if the receiver does dithering)? 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] How I got my FE-5680A to lock in Sydney, Australia
Could this be a case of the Rb settling on the bottom of the bulb and then being vaporized when the bottom became the top? Bob From: Jamieson (Jim) Rowe jimr...@optusnet.com.au To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sunday, February 9, 2014 6:39 PM Subject: Re: [time-nuts] How I got my FE-5680A to lock in Sydney, Australia Hi again Magnus, Mark, Tom Harris, Ed Palmer et al, snip But wait for it -- it then locked up, reliably, in the right-side-up position! ___ 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] Line Frequency
On Sun, Feb 9, 2014 at 4:27 PM, M. Simon msimon6...@yahoo.com wrote: Tom, I was hoping for 1E-5 precision or better. My time stamping counter will have a 30 MHz clock (for convenience). I think noise will not allow that level of accuracy with only one time stamp per cycle. I think you'd be better off making many samples per cycle. Taking 48,000 samples per second give 800 samples per cycle. 48K is the standard sample rate for audio used with video.Likely your computer already has the means to sample two audio signals at 48K samples per second. It is not taxing on any modern computer or even for a smart phone. Doing this on my iMac is so trivial I don't bother to save the setup. I have an audio interface to samples 24 bits at 96K SPS. I placed a 1 volt peak to peak signal on it and then brought up a spectra display. I can log the spectra to a file. This kind of software is available for free. 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] How I got my FE-5680A to lock in Sydney, Australia
Jim wrote: Here's what I found, as before looking at the frequency with my counter (GPSDXO 1pps timebase): Inverted position: swings between 9,999,798Hz and 10,000,001Hz, before locking. Normal position: swings between 9,999,756Hz and 10,000,057Hz, a few times. Are you sure you didn't transpose the high swing numbers? As you state it above, the oscillator swings 203 Hz (peak-to-peak) when inverted and 301 Hz p-p right-side-up. If we swap the high swing numbers, it is 245 Hz inverted and 259 Hz right-side-up, which seems more plausible. There seems to be little reason why the absolute value of the sweep range would vary so much (203 to 301). Also, a normal range of 9,999,756 to 10,000,001 and an inverted range of 9,999,798 to 10,000,057 would seem to explain your previous results, while the results reported above would not. I'm a little confused by what you've said about your counter time base -- as I recall, you said you were feeding GPS 1pps to the counter. I'm not familiar with any counter that locks to 1pps -- most counters I'm familiar with lock to 10MHz (or in older gear, 5MHz or 1MHz). Can you say a bit more about your 1pps timebase? Best regards, Charles ___ 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.
