Re: [time-nuts] Measuring Phase diference between different GPSDO
-Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark C. Stephens Sent: Thursday, May 02, 2013 9:29 PM To: li...@lazygranch.com; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Measuring Phase diference between different GPSDO According to http://www.realhamradio.com/z3801a-turning-point.htm they use a HP 3575A phase meter to perform the measurement. Or perhaps I have misinterpreted the whole thing? 5370Bs were a $20,000 instrument by the time they went out of production, so that's probably why HP recommended the use of a more economical phase meter. Given that you have a 5370B, it's definitely the right thing to use. -- john, KE5FX Miles Design LLC ___ 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] Measuring Phase diference between different GPSDO
Hi If you have a pile of GPIB cables, you may also have a GPIB card on a PC. You will have a lot more luck finding free software to read and log the data from the 5370 than from the 3575. As mentioned before, the 5370 will be much more accurate / higher resolution in this application. Bob On May 3, 2013, at 12:28 AM, Mark C. Stephens ma...@non-stop.com.au wrote: According to http://www.realhamradio.com/z3801a-turning-point.htm they use a HP 3575A phase meter to perform the measurement. Or perhaps I have misinterpreted the whole thing? I do have a temperature controlled workshop that is always 24 degrees so hopefully thermal drift won't be too much of an issue. mark -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of li...@lazygranch.com Sent: Friday, 3 May 2013 12:12 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Measuring Phase diference between different GPSDO Meditating on this a bit, I assume in a strict sense, you can only consider GPSDOs phase locked if they are disciplined from the same GPS. Or is this being pedantic? ___ 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] Looking for HP115BR service manual
I am looking for the HP115BR service manual. thank You -- Luciano Timeok visit : www.timeok.it ___ 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] Measuring Phase diference between different GPSDO
Now the trick is: How to use the 5370B to measure the phase difference. Anyone care to point me towards an APP note or two?! mark -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of John Miles Sent: Friday, 3 May 2013 5:30 PM To: 'Discussion of precise time and frequency measurement'; li...@lazygranch.com Subject: Re: [time-nuts] Measuring Phase diference between different GPSDO -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark C. Stephens Sent: Thursday, May 02, 2013 9:29 PM To: li...@lazygranch.com; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Measuring Phase diference between different GPSDO According to http://www.realhamradio.com/z3801a-turning-point.htm they use a HP 3575A phase meter to perform the measurement. Or perhaps I have misinterpreted the whole thing? 5370Bs were a $20,000 instrument by the time they went out of production, so that's probably why HP recommended the use of a more economical phase meter. Given that you have a 5370B, it's definitely the right thing to use. -- john, KE5FX Miles Design LLC ___ 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] Measuring Phase diference between different GPSDO
Hey Bob, I was thinking the exact same thought, and I found a NI PCI-GPIB card in a PC with a dead HDD. These appear to be 5V PCI cards so I can't stick it in a nice rack mount server with raid as they all seem to be 3.3v PCI. So I put a new HDD in the PC and I have stuck WinXP on it. Now I am awaiting further orders! ;) mark -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Camp Sent: Friday, 3 May 2013 9:21 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Measuring Phase diference between different GPSDO Hi If you have a pile of GPIB cables, you may also have a GPIB card on a PC. You will have a lot more luck finding free software to read and log the data from the 5370 than from the 3575. As mentioned before, the 5370 will be much more accurate / higher resolution in this application. Bob On May 3, 2013, at 12:28 AM, Mark C. Stephens ma...@non-stop.com.au wrote: According to http://www.realhamradio.com/z3801a-turning-point.htm they use a HP 3575A phase meter to perform the measurement. Or perhaps I have misinterpreted the whole thing? I do have a temperature controlled workshop that is always 24 degrees so hopefully thermal drift won't be too much of an issue. mark -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of li...@lazygranch.com Sent: Friday, 3 May 2013 12:12 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Measuring Phase diference between different GPSDO Meditating on this a bit, I assume in a strict sense, you can only consider GPSDOs phase locked if they are disciplined from the same GPS. Or is this being pedantic? ___ 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] Measuring Phase diference between different GPSDO
5370, PC, XP, GPIB... you are ready for the TimeLab! On Fri, May 3, 2013 at 4:12 PM, Azelio Boriani azelio.bori...@screen.itwrote: Take a look at the TimeLab software http://www.ke5fx.com/timelab/readme.htm that reads directly the 5370. On Fri, May 3, 2013 at 4:04 PM, Mark C. Stephens ma...@non-stop.com.auwrote: Now the trick is: How to use the 5370B to measure the phase difference. Anyone care to point me towards an APP note or two?! mark -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of John Miles Sent: Friday, 3 May 2013 5:30 PM To: 'Discussion of precise time and frequency measurement'; li...@lazygranch.com Subject: Re: [time-nuts] Measuring Phase diference between different GPSDO -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark C. Stephens Sent: Thursday, May 02, 2013 9:29 PM To: li...@lazygranch.com; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Measuring Phase diference between different GPSDO According to http://www.realhamradio.com/z3801a-turning-point.htm they use a HP 3575A phase meter to perform the measurement. Or perhaps I have misinterpreted the whole thing? 5370Bs were a $20,000 instrument by the time they went out of production, so that's probably why HP recommended the use of a more economical phase meter. Given that you have a 5370B, it's definitely the right thing to use. -- john, KE5FX Miles Design LLC ___ 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] Measuring Phase diference between different GPSDO
Take a look at the TimeLab software http://www.ke5fx.com/timelab/readme.htmthat reads directly the 5370. On Fri, May 3, 2013 at 4:04 PM, Mark C. Stephens ma...@non-stop.com.auwrote: Now the trick is: How to use the 5370B to measure the phase difference. Anyone care to point me towards an APP note or two?! mark -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of John Miles Sent: Friday, 3 May 2013 5:30 PM To: 'Discussion of precise time and frequency measurement'; li...@lazygranch.com Subject: Re: [time-nuts] Measuring Phase diference between different GPSDO -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark C. Stephens Sent: Thursday, May 02, 2013 9:29 PM To: li...@lazygranch.com; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Measuring Phase diference between different GPSDO According to http://www.realhamradio.com/z3801a-turning-point.htm they use a HP 3575A phase meter to perform the measurement. Or perhaps I have misinterpreted the whole thing? 5370Bs were a $20,000 instrument by the time they went out of production, so that's probably why HP recommended the use of a more economical phase meter. Given that you have a 5370B, it's definitely the right thing to use. -- john, KE5FX Miles Design LLC ___ 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] Measuring Phase difference between different GPSDO
Hi Grab an old garage sale category PC, blow the dust out of it and fire up the GPIB. Once it's all working next steps: Check out TimeLab and EZGpib. Both are pretty good at talking to stuff. TimeLab does support the 5370, not sure about the other programs. If you have two GPSDO's with pps outputs, feed one into each channel on the 5370. Put it in start / stop mode and you should see the difference between the two. Since they can be either ahead or behind each other things can get a little messy. Next, go to the software that runs your GPSDO and look for the cable delay setting. Adjust it on one GPSDO so it's always early (or late) by a couple hundred nanoseconds. Now fiddle the cables to the counter so it reads a couple hundred nanoseconds and not almost a full second :). At this point you are reading frequency to a very high resolution. The GPSDO's likely are only good to a couple of nanoseconds at 1 second. The counter should be good to ~0.02 ns. Run like this for a few minutes and see what you get. --- Now that you have conquered that approach it's time to tear it all apart and try something new. Feed the 1 pps into one input of the counter (just like before). Hit the other input with 10 MHz. You now will get a reading in the 0 to 100 ns range. Each time a cycle slips past the 1 pps the reading will skip from 99.xxx to 0.xxx ns. That's called a phase wrap around. Click the appropriate boxes on which ever software you are running and it should take care of the wrap. Either way the software should show you frequency, and frequency stability. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark C. Stephens Sent: Friday, May 03, 2013 10:07 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Measuring Phase diference between different GPSDO Hey Bob, I was thinking the exact same thought, and I found a NI PCI-GPIB card in a PC with a dead HDD. These appear to be 5V PCI cards so I can't stick it in a nice rack mount server with raid as they all seem to be 3.3v PCI. So I put a new HDD in the PC and I have stuck WinXP on it. Now I am awaiting further orders! ;) mark -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Camp Sent: Friday, 3 May 2013 9:21 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Measuring Phase diference between different GPSDO Hi If you have a pile of GPIB cables, you may also have a GPIB card on a PC. You will have a lot more luck finding free software to read and log the data from the 5370 than from the 3575. As mentioned before, the 5370 will be much more accurate / higher resolution in this application. Bob On May 3, 2013, at 12:28 AM, Mark C. Stephens ma...@non-stop.com.au wrote: According to http://www.realhamradio.com/z3801a-turning-point.htm they use a HP 3575A phase meter to perform the measurement. Or perhaps I have misinterpreted the whole thing? I do have a temperature controlled workshop that is always 24 degrees so hopefully thermal drift won't be too much of an issue. mark -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of li...@lazygranch.com Sent: Friday, 3 May 2013 12:12 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Measuring Phase diference between different GPSDO Meditating on this a bit, I assume in a strict sense, you can only consider GPSDOs phase locked if they are disciplined from the same GPS. Or is this being pedantic? ___ 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. ___ 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] hp5065b !!!
I'm interested in these improvements too, and hope some can be applied to other models. I don't have a 5065A, nor do I expect to ever get one, but I do have three identical old Efratom units. Whether it's worthwhile to modify any Rb units also depends on whether it's possible to rejuvenate their Rb lamps, as discussed here a number of times, so that they can be maintained virtually indefinitely. Ed ___ 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] Measuring Phase difference between different GPSDO
Am on the way to doing my first 'phase difference' with timelab - takes an hour :) This is good stuff, everything went so smoothly, from installing the OS to using Timelab. Now I have to figure out how to measure and set the xtal turning temperature for this bunch of Z3805A's I have here. I have a Z3816A that is super stable. SYST:STAT? usually reports 0.0us for PU, sometimes it will go out as far as 0.2us, but very rarely :p So I am planning on using that guy as my reference to tune the Z3805A's. How does that sound? Many thanks, mark -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Camp Sent: Saturday, 4 May 2013 1:09 AM To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] Measuring Phase difference between different GPSDO Hi Grab an old garage sale category PC, blow the dust out of it and fire up the GPIB. Once it's all working next steps: Check out TimeLab and EZGpib. Both are pretty good at talking to stuff. TimeLab does support the 5370, not sure about the other programs. If you have two GPSDO's with pps outputs, feed one into each channel on the 5370. Put it in start / stop mode and you should see the difference between the two. Since they can be either ahead or behind each other things can get a little messy. Next, go to the software that runs your GPSDO and look for the cable delay setting. Adjust it on one GPSDO so it's always early (or late) by a couple hundred nanoseconds. Now fiddle the cables to the counter so it reads a couple hundred nanoseconds and not almost a full second :). At this point you are reading frequency to a very high resolution. The GPSDO's likely are only good to a couple of nanoseconds at 1 second. The counter should be good to ~0.02 ns. Run like this for a few minutes and see what you get. --- Now that you have conquered that approach it's time to tear it all apart and try something new. Feed the 1 pps into one input of the counter (just like before). Hit the other input with 10 MHz. You now will get a reading in the 0 to 100 ns range. Each time a cycle slips past the 1 pps the reading will skip from 99.xxx to 0.xxx ns. That's called a phase wrap around. Click the appropriate boxes on which ever software you are running and it should take care of the wrap. Either way the software should show you frequency, and frequency stability. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark C. Stephens Sent: Friday, May 03, 2013 10:07 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Measuring Phase diference between different GPSDO Hey Bob, I was thinking the exact same thought, and I found a NI PCI-GPIB card in a PC with a dead HDD. These appear to be 5V PCI cards so I can't stick it in a nice rack mount server with raid as they all seem to be 3.3v PCI. So I put a new HDD in the PC and I have stuck WinXP on it. Now I am awaiting further orders! ;) mark -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Camp Sent: Friday, 3 May 2013 9:21 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Measuring Phase diference between different GPSDO Hi If you have a pile of GPIB cables, you may also have a GPIB card on a PC. You will have a lot more luck finding free software to read and log the data from the 5370 than from the 3575. As mentioned before, the 5370 will be much more accurate / higher resolution in this application. Bob On May 3, 2013, at 12:28 AM, Mark C. Stephens ma...@non-stop.com.au wrote: According to http://www.realhamradio.com/z3801a-turning-point.htm they use a HP 3575A phase meter to perform the measurement. Or perhaps I have misinterpreted the whole thing? I do have a temperature controlled workshop that is always 24 degrees so hopefully thermal drift won't be too much of an issue. mark -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of li...@lazygranch.com Sent: Friday, 3 May 2013 12:12 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Measuring Phase diference between different GPSDO Meditating on this a bit, I assume in a strict sense, you can only consider GPSDOs phase locked if they are disciplined from the same GPS. Or is this being pedantic? ___ 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] Measuring Phase difference between different GPSDO
Hi Sounds like you are up and running. TimeLab can be set for any length run you wish. Three to five minutes is a common one. I have a 30 day run going at the moment. Even while the run is going, you can switch between displays to see what's happening. Unless you have some very unusual OCXO's in your 3805's fiddling with the oven temperature isn't going to help things much. If they are SC based, there may not be a turn over temperature. Often the set point is derived either from crystal data or from wide range temp run performance. Like any piece of surplus, you can indeed have something broken somewhere. In that case, repair is a good idea. Unless you blew the thermistor in the OCXO, it's an unlikely repair though. Bob On May 3, 2013, at 12:48 PM, Mark C. Stephens ma...@non-stop.com.au wrote: Am on the way to doing my first 'phase difference' with timelab - takes an hour :) This is good stuff, everything went so smoothly, from installing the OS to using Timelab. Now I have to figure out how to measure and set the xtal turning temperature for this bunch of Z3805A's I have here. I have a Z3816A that is super stable. SYST:STAT? usually reports 0.0us for PU, sometimes it will go out as far as 0.2us, but very rarely :p So I am planning on using that guy as my reference to tune the Z3805A's. How does that sound? Many thanks, mark -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Camp Sent: Saturday, 4 May 2013 1:09 AM To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] Measuring Phase difference between different GPSDO Hi Grab an old garage sale category PC, blow the dust out of it and fire up the GPIB. Once it's all working next steps: Check out TimeLab and EZGpib. Both are pretty good at talking to stuff. TimeLab does support the 5370, not sure about the other programs. If you have two GPSDO's with pps outputs, feed one into each channel on the 5370. Put it in start / stop mode and you should see the difference between the two. Since they can be either ahead or behind each other things can get a little messy. Next, go to the software that runs your GPSDO and look for the cable delay setting. Adjust it on one GPSDO so it's always early (or late) by a couple hundred nanoseconds. Now fiddle the cables to the counter so it reads a couple hundred nanoseconds and not almost a full second :). At this point you are reading frequency to a very high resolution. The GPSDO's likely are only good to a couple of nanoseconds at 1 second. The counter should be good to ~0.02 ns. Run like this for a few minutes and see what you get. --- Now that you have conquered that approach it's time to tear it all apart and try something new. Feed the 1 pps into one input of the counter (just like before). Hit the other input with 10 MHz. You now will get a reading in the 0 to 100 ns range. Each time a cycle slips past the 1 pps the reading will skip from 99.xxx to 0.xxx ns. That's called a phase wrap around. Click the appropriate boxes on which ever software you are running and it should take care of the wrap. Either way the software should show you frequency, and frequency stability. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark C. Stephens Sent: Friday, May 03, 2013 10:07 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Measuring Phase diference between different GPSDO Hey Bob, I was thinking the exact same thought, and I found a NI PCI-GPIB card in a PC with a dead HDD. These appear to be 5V PCI cards so I can't stick it in a nice rack mount server with raid as they all seem to be 3.3v PCI. So I put a new HDD in the PC and I have stuck WinXP on it. Now I am awaiting further orders! ;) mark -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Camp Sent: Friday, 3 May 2013 9:21 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Measuring Phase diference between different GPSDO Hi If you have a pile of GPIB cables, you may also have a GPIB card on a PC. You will have a lot more luck finding free software to read and log the data from the 5370 than from the 3575. As mentioned before, the 5370 will be much more accurate / higher resolution in this application. Bob On May 3, 2013, at 12:28 AM, Mark C. Stephens ma...@non-stop.com.au wrote: According to http://www.realhamradio.com/z3801a-turning-point.htm they use a HP 3575A phase meter to perform the measurement. Or perhaps I have misinterpreted the whole thing? I do have a temperature controlled workshop that is always 24 degrees so hopefully thermal drift won't be too much of an issue.
Re: [time-nuts] hp5065b !!!
Hi One of the unique things about the 5065 is it's great big cells. The small cell compact Rb's are a very different beast. There is a body of evidence suggesting that the cell size is significant for ultra low ADEV. The basic concepts of improving signal (light intensity) and signal to noise (filtering) would apply to other units. Weather the mods give significant improvements on small cells is the open question. The compact Rb's may already be at the floor for their cell size…. Bob On May 3, 2013, at 10:40 AM, ed breya e...@telight.com wrote: I'm interested in these improvements too, and hope some can be applied to other models. I don't have a 5065A, nor do I expect to ever get one, but I do have three identical old Efratom units. Whether it's worthwhile to modify any Rb units also depends on whether it's possible to rejuvenate their Rb lamps, as discussed here a number of times, so that they can be maintained virtually indefinitely. Ed ___ 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] hp5065b !!!
In message bb988fb5-d829-4c9d-a8bd-f2c8731b8...@rtty.us, Bob Camp writes: The basic concepts of improving signal (light intensity) and signal to noise (filtering) would apply to other units. I was wondering about that. The normally quoted number for change in (detected) light intensity is approx 0.1%. It would be interesting to find out if this changes significantly with the extra filtering ? If so, that would likely help smaller cells more than big cells... -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Extended length Phase Noise Measurements with TimeLab
Recently I was looking at a co-workers Lab View measurements taken with a 5120A. She is studying vibration on Phase Noise. I asked how Lab View compared to TimeLab and she said in many ways she prefers TimeLab but ran into a problem. The research she is currently conducting requires collecting data in extremely long measurement periods beyond the TimeLab limits. Is she missing something? If not is measurement length an easy fix? One other problem during her project was related to the 5120A, occasionally the vibration must hit a resonance and the 5120A stops measurement saying measurement parameters were exceeded. It would be nice to be able to adjust or disable that feature. Thanks in advance for your ideas. Thomas Knox ___ 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] Extended length Phase Noise Measurements with TimeLab
Hi Tom -- Are you talking about capture time limits, or minimum tau? I've never encountered any capture time limits in TimeLab and have done out to 30 days. However, one thing I have noticed with the 5120A ethernet using my own capture software is that the data flow will sometimes stop for several seconds and then restart. You don't actually lose any samples, but the client software can suffer a TCP timeout. I got around this by setting the timeout in my software (using Perl's libtelnet module under Linux) to something like 30 seconds. That solved the issue for me. I've never seen the TCP timeout affect TimeLab; I don't know what kind of time limit John has coded but it seems to be long enough. Re the 5120A itself erroring out, it does complain if either the frequency or the amplitude change too much during the measurement. Unfortunately, I don't know of a way to disable that. John On 5/3/2013 2:21 PM, Tom Knox wrote: Recently I was looking at a co-workers Lab View measurements taken with a 5120A. She is studying vibration on Phase Noise. I asked how Lab View compared to TimeLab and she said in many ways she prefers TimeLab but ran into a problem. The research she is currently conducting requires collecting data in extremely long measurement periods beyond the TimeLab limits. Is she missing something? If not is measurement length an easy fix? One other problem during her project was related to the 5120A, occasionally the vibration must hit a resonance and the 5120A stops measurement saying measurement parameters were exceeded. It would be nice to be able to adjust or disable that feature. Thanks in advance for your ideas. Thomas Knox ___ 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] Extended length Phase Noise Measurements with TimeLab
As JohnA says there's no hard limit on the duration for phase data logging, other than available RAM. She would definitely want to use a 64-bit PC for this. The TSC 5120A cranks out phase data at 1000 samples per second by default, so even a well-endowed 64 bit PC will run out of memory when trying to record for 1 day. Two things you can do about that: - Use the 'set phaserate' command over a Telnet connection to lower the data rate from the 5120A to 10 or 100 samples per second. Change the 'Input Data Rate' field in the TimeLab acquisition dialog accordingly. This will work only with newer 5120A firmware. - Leave the TSC's phase data rate (and the Input Data Rate field) at 1000 samples/second and use the Output Decimation field to reduce the amount of stored data. Both of those options should be used with TimeLab 1.1 or greater. For the issue where the 5120A stops the measurement, I'd log the signal with a counter or a scope, maybe, to make sure that the signal isn't going even farther out of range than expected. If so, it would be best to fix that problem at the source. Otherwise, consider using a bandpass filter or PLL whose bandwidth is wide enough to accommodate the desired analysis spectrum but narrow enough to act as a flywheel during the (hopefully brief) excursions that are confusing the 5120A. -- john, KE5FX Miles Design LLC -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Tom Knox Sent: Friday, May 03, 2013 11:22 AM To: Time-Nuts Subject: [time-nuts] Extended length Phase Noise Measurements with TimeLab Recently I was looking at a co-workers Lab View measurements taken with a 5120A. She is studying vibration on Phase Noise. I asked how Lab View compared to TimeLab and she said in many ways she prefers TimeLab but ran into a problem. The research she is currently conducting requires collecting data in extremely long measurement periods beyond the TimeLab limits. Is she missing something? If not is measurement length an easy fix? One other problem during her project was related to the 5120A, occasionally the vibration must hit a resonance and the 5120A stops measurement saying measurement parameters were exceeded. It would be nice to be able to adjust or disable that feature. Thanks in advance for your ideas. Thomas Knox ___ 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] Extended length Phase Noise Measurements with TimeLab
Hi There are some warning messages in TimeLab about runs with more than xx,xxx,xxx,xxx,xxx,xxx samples in them may harm poor fuzzy animals. I've routinely exceeded them with no obvious damage to the local environment. I may not have the wording of the error message quite right…. If the resonance on the vibration table is enough to push the frequency beyond a certain point, all of these boxes get a bit bothered. The 5120 is by no means unique in that regard. The trip points vary from model to model. The ones I seem to remember were in the 10's of ppm. Bob On May 3, 2013, at 2:21 PM, Tom Knox act...@hotmail.com wrote: Recently I was looking at a co-workers Lab View measurements taken with a 5120A. She is studying vibration on Phase Noise. I asked how Lab View compared to TimeLab and she said in many ways she prefers TimeLab but ran into a problem. The research she is currently conducting requires collecting data in extremely long measurement periods beyond the TimeLab limits. Is she missing something? If not is measurement length an easy fix? One other problem during her project was related to the 5120A, occasionally the vibration must hit a resonance and the 5120A stops measurement saying measurement parameters were exceeded. It would be nice to be able to adjust or disable that feature. Thanks in advance for your ideas. Thomas Knox ___ 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] Measuring Phase difference between different GPSDO
Actually Bob, What put me onto this was one of the Z3805A, the PU decreases dramatically when a cooling fan is pointed at it. The Second one, is the opposite, positioned near the hot air exhaust of a server gets the best PU. I have 3 other Z3805A which I have yet to play with. Am I onto something or clutching at straws? mark -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Camp Sent: Saturday, 4 May 2013 3:01 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Measuring Phase difference between different GPSDO Hi Sounds like you are up and running. TimeLab can be set for any length run you wish. Three to five minutes is a common one. I have a 30 day run going at the moment. Even while the run is going, you can switch between displays to see what's happening. Unless you have some very unusual OCXO's in your 3805's fiddling with the oven temperature isn't going to help things much. If they are SC based, there may not be a turn over temperature. Often the set point is derived either from crystal data or from wide range temp run performance. Like any piece of surplus, you can indeed have something broken somewhere. In that case, repair is a good idea. Unless you blew the thermistor in the OCXO, it's an unlikely repair though. Bob On May 3, 2013, at 12:48 PM, Mark C. Stephens ma...@non-stop.com.au wrote: Am on the way to doing my first 'phase difference' with timelab - takes an hour :) This is good stuff, everything went so smoothly, from installing the OS to using Timelab. Now I have to figure out how to measure and set the xtal turning temperature for this bunch of Z3805A's I have here. I have a Z3816A that is super stable. SYST:STAT? usually reports 0.0us for PU, sometimes it will go out as far as 0.2us, but very rarely :p So I am planning on using that guy as my reference to tune the Z3805A's. How does that sound? Many thanks, mark -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Camp Sent: Saturday, 4 May 2013 1:09 AM To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] Measuring Phase difference between different GPSDO Hi Grab an old garage sale category PC, blow the dust out of it and fire up the GPIB. Once it's all working next steps: Check out TimeLab and EZGpib. Both are pretty good at talking to stuff. TimeLab does support the 5370, not sure about the other programs. If you have two GPSDO's with pps outputs, feed one into each channel on the 5370. Put it in start / stop mode and you should see the difference between the two. Since they can be either ahead or behind each other things can get a little messy. Next, go to the software that runs your GPSDO and look for the cable delay setting. Adjust it on one GPSDO so it's always early (or late) by a couple hundred nanoseconds. Now fiddle the cables to the counter so it reads a couple hundred nanoseconds and not almost a full second :). At this point you are reading frequency to a very high resolution. The GPSDO's likely are only good to a couple of nanoseconds at 1 second. The counter should be good to ~0.02 ns. Run like this for a few minutes and see what you get. --- Now that you have conquered that approach it's time to tear it all apart and try something new. Feed the 1 pps into one input of the counter (just like before). Hit the other input with 10 MHz. You now will get a reading in the 0 to 100 ns range. Each time a cycle slips past the 1 pps the reading will skip from 99.xxx to 0.xxx ns. That's called a phase wrap around. Click the appropriate boxes on which ever software you are running and it should take care of the wrap. Either way the software should show you frequency, and frequency stability. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark C. Stephens Sent: Friday, May 03, 2013 10:07 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Measuring Phase diference between different GPSDO Hey Bob, I was thinking the exact same thought, and I found a NI PCI-GPIB card in a PC with a dead HDD. These appear to be 5V PCI cards so I can't stick it in a nice rack mount server with raid as they all seem to be 3.3v PCI. So I put a new HDD in the PC and I have stuck WinXP on it. Now I am awaiting further orders! ;) mark -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Camp Sent: Friday, 3 May 2013 9:21 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Measuring Phase diference between different GPSDO Hi If you have a pile of GPIB cables, you may also have a GPIB card
Re: [time-nuts] Extended length Phase Noise Measurements with TimeLab
Yes, those messages are just there to warn users that if they try to record multi-million point phase records, they may either run out of memory or generate a gigabyte+ file that will be painfully slow to work with. The warning threshold is quite a bit higher in the 64-bit version but it will still pop up if you get too aggressive with the data rate and/or duration. -- john, KE5FX Miles Design LLC -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Camp Sent: Friday, May 03, 2013 1:46 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Extended length Phase Noise Measurements with TimeLab Hi There are some warning messages in TimeLab about runs with more than xx,xxx,xxx,xxx,xxx,xxx samples in them may harm poor fuzzy animals. I've routinely exceeded them with no obvious damage to the local environment. I may not have the wording of the error message quite right.. If the resonance on the vibration table is enough to push the frequency beyond a certain point, all of these boxes get a bit bothered. The 5120 is by no means unique in that regard. The trip points vary from model to model. The ones I seem to remember were in the 10's of ppm. Bob On May 3, 2013, at 2:21 PM, Tom Knox act...@hotmail.com wrote: Recently I was looking at a co-workers Lab View measurements taken with a 5120A. She is studying vibration on Phase Noise. I asked how Lab View compared to TimeLab and she said in many ways she prefers TimeLab but ran into a problem. The research she is currently conducting requires collecting data in extremely long measurement periods beyond the TimeLab limits. Is she missing something? If not is measurement length an easy fix? One other problem during her project was related to the 5120A, occasionally the vibration must hit a resonance and the 5120A stops measurement saying measurement parameters were exceeded. It would be nice to be able to adjust or disable that feature. Thanks in advance for your ideas. Thomas Knox ___ 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] Extended length Phase Noise Measurements with TimeLab
Tom, For long measurement runs especially, I almost always do my data collection separately from my data analysis and plotting. That way there is no TimeLab CPU or RAM limit. You can start/stop/exit TimeLab or Stable32 or Plotter or Excel at will without worrying about losing raw data. The data collection tool I use does a file checkpoint every minute, so if there is an app or OS or PC or cable or switch or TSC glitch or TSC crash or lab power failure I don't lose hours or days or weeks of data. It also means I can use old cheap PC's that run at 1% busy (no fan) to log tens of data streams instead of having to have an instance(s) of TimeLab peg my CPU and turn my laptop into a hair dryer. I collect TSC 5110A and 5120A data from serial (1 Hz) and LAN (1 kHz) ports. I have never, ever, had problems with serial data. Serial ports may be old fashion but they are stateless and so more reliable for data logging than stateful USB or LAN connections. I do have issues with long-term reliability of the TSC 5120 LAN port data stream. The TCP timeout bug was introduced in one of the very early firmware upgrades and no one has been able to track it down. I've spent hours snooping packets. The pre-production TSC5120/BSD firmware used to output 1 kHz phase samples evenly about every millisecond over ethernet. At some point before production the firmware got smart and buffered packets into chunks as large as 1024 or 5120 or 8192 samples each. My hunch is this optimization correlates with the rare TCP hangs that users see. I've tried multiple PC's and multiple OS's with the same result so I'm pretty sure it's the TSC firmware, and not me or my PC's or even TSC hardware to blame. I can't help you with the measurement parameters exceeded problem. I know the TSC boxes have limits on dynamic frequency variations. To debug, or at least to get around this, I would run a high-res frequency counter (like a 53132A or CNT-90) in parallel with the TSC analyzer, since those counters have no dynamic range limits. /tvb - Original Message - From: Tom Knox act...@hotmail.com To: Time-Nuts time-nuts@febo.com Sent: Friday, May 03, 2013 11:21 AM Subject: [time-nuts] Extended length Phase Noise Measurements with TimeLab Recently I was looking at a co-workers Lab View measurements taken with a 5120A. She is studying vibration on Phase Noise. I asked how Lab View compared to TimeLab and she said in many ways she prefers TimeLab but ran into a problem. The research she is currently conducting requires collecting data in extremely long measurement periods beyond the TimeLab limits. Is she missing something? If not is measurement length an easy fix? One other problem during her project was related to the 5120A, occasionally the vibration must hit a resonance and the 5120A stops measurement saying measurement parameters were exceeded. It would be nice to be able to adjust or disable that feature. Thanks in advance for your ideas. Thomas Knox ___ 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] hp5065b !!!
Great big and small Rb cells: http://leapsecond.com/corby/rb-lamp.htm Also: http://leapsecond.com/corby/5065a-optical/ /tvb - Original Message - From: Bob Camp li...@rtty.us To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Friday, May 03, 2013 10:07 AM Subject: Re: [time-nuts] hp5065b !!! Hi One of the unique things about the 5065 is it's great big cells. The small cell compact Rb's are a very different beast. There is a body of evidence suggesting that the cell size is significant for ultra low ADEV. The basic concepts of improving signal (light intensity) and signal to noise (filtering) would apply to other units. Weather the mods give significant improvements on small cells is the open question. The compact Rb's may already be at the floor for their cell size…. Bob On May 3, 2013, at 10:40 AM, ed breya e...@telight.com wrote: I'm interested in these improvements too, and hope some can be applied to other models. I don't have a 5065A, nor do I expect to ever get one, but I do have three identical old Efratom units. Whether it's worthwhile to modify any Rb units also depends on whether it's possible to rejuvenate their Rb lamps, as discussed here a number of times, so that they can be maintained virtually indefinitely. Ed ___ 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] 5V antenna on 3V receiver via dist. amp?
Thats fine If the 3 v rcvr complains connect a 450 ohm from the antenna to ground that should make it happy. The resistor really isn't picky On Thu, May 2, 2013 at 10:38 PM, Paul tic-...@bodosom.net wrote: On Thu, May 2, 2013 at 5:51 PM, time-nuts-requ...@febo.com wrote: A distribution amplifier (like the 58516A) should also be OK. If you are going to have a GPS receiver that can provide 5V to the antenna and amplifier, that would be ideal. Yes, my plan was to attach a 5V receiver to power in (port 1 on a 58516A) and 3V receivers to the DC-blocked ports. ___ 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] Measuring Phase diference between different GPSDO
How about just running the two different 10 mhz outputs into a doubly balanced mixer and monitoring the DC output with a volt meter from the IF port of the mixer? Sure beats $20,000 for a fancy HP. Of course this is a very simple method and is boring as heck to sit and watch a voltmeter but it could easily be automated. Suitable doubly balanced mixers can be often found on eBay for under $50. I found a nice Mini-Circuit unit with BNC connectors for around $20 that I have often used. I often just use a scope and Lissajous figures for looking at phase differences. Al, K9SI Now the trick is: How to use the 5370B to measure the phase difference. Anyone care to point me towards an APP note or two?! mark ___ 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] Measuring Phase difference between different GPSDO
Hi OCXO's don't really like major temperature changes. They are much happier in steady state environments. Transient behavior may or may not correlate with steady state behavior, so trying to correct it by fiddling the oven - not a good idea. The one exception to that would be if the oven has burned out. In that case the EFC voltage should be pegged. --- Better way to start: Fire up the software of your choice on the PC. Let it talk to the Z3805's make sure that it's doing what it should (locking up to GPS etc). I'm guessing that's already taken care of. Let it run for a while and watch the EFC voltage. It'll start out moving fairly quickly. After a few days / weeks it should settle out. It should be near center scale after settling. While the OCXO is settling out, you can watch the PPS output and the 10 MHz. The 10 MHz should be pretty close after the first day or two. In this case pretty close is 0.1 Hz on the 10 MHz. Pretty close on the pps should be 20 ns. If they are not, the disciplining part of the unit is broke. Depending on what you do / don't find there are lots of different directions to head. Bob On May 3, 2013, at 5:04 PM, Mark C. Stephens ma...@non-stop.com.au wrote: Actually Bob, What put me onto this was one of the Z3805A, the PU decreases dramatically when a cooling fan is pointed at it. The Second one, is the opposite, positioned near the hot air exhaust of a server gets the best PU. I have 3 other Z3805A which I have yet to play with. Am I onto something or clutching at straws? mark -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Camp Sent: Saturday, 4 May 2013 3:01 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Measuring Phase difference between different GPSDO Hi Sounds like you are up and running. TimeLab can be set for any length run you wish. Three to five minutes is a common one. I have a 30 day run going at the moment. Even while the run is going, you can switch between displays to see what's happening. Unless you have some very unusual OCXO's in your 3805's fiddling with the oven temperature isn't going to help things much. If they are SC based, there may not be a turn over temperature. Often the set point is derived either from crystal data or from wide range temp run performance. Like any piece of surplus, you can indeed have something broken somewhere. In that case, repair is a good idea. Unless you blew the thermistor in the OCXO, it's an unlikely repair though. Bob On May 3, 2013, at 12:48 PM, Mark C. Stephens ma...@non-stop.com.au wrote: Am on the way to doing my first 'phase difference' with timelab - takes an hour :) This is good stuff, everything went so smoothly, from installing the OS to using Timelab. Now I have to figure out how to measure and set the xtal turning temperature for this bunch of Z3805A's I have here. I have a Z3816A that is super stable. SYST:STAT? usually reports 0.0us for PU, sometimes it will go out as far as 0.2us, but very rarely :p So I am planning on using that guy as my reference to tune the Z3805A's. How does that sound? Many thanks, mark -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Camp Sent: Saturday, 4 May 2013 1:09 AM To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] Measuring Phase difference between different GPSDO Hi Grab an old garage sale category PC, blow the dust out of it and fire up the GPIB. Once it's all working next steps: Check out TimeLab and EZGpib. Both are pretty good at talking to stuff. TimeLab does support the 5370, not sure about the other programs. If you have two GPSDO's with pps outputs, feed one into each channel on the 5370. Put it in start / stop mode and you should see the difference between the two. Since they can be either ahead or behind each other things can get a little messy. Next, go to the software that runs your GPSDO and look for the cable delay setting. Adjust it on one GPSDO so it's always early (or late) by a couple hundred nanoseconds. Now fiddle the cables to the counter so it reads a couple hundred nanoseconds and not almost a full second :). At this point you are reading frequency to a very high resolution. The GPSDO's likely are only good to a couple of nanoseconds at 1 second. The counter should be good to ~0.02 ns. Run like this for a few minutes and see what you get. --- Now that you have conquered that approach it's time to tear it all apart and try something new. Feed the 1 pps into one input of the counter (just like before). Hit the other input with 10 MHz. You now will get a reading in the 0 to 100 ns range. Each time a cycle slips past the 1 pps the reading will
