Re: [time-nuts] Logging the grid frequency....
So it is not correct to measure one point to a gnat's nose hair and call it the grid frequency. Bill, Yes, and this is true for any source of frequency. That's why when we specify stability the averaging interval is critical; the x-axis of a log-log ADEV plot. One might look at every cycle to measure stuff like jitter, not so much to measure frequency over a tau of 0.016 seconds. The nice thing about ADEV is that a single plot can convey frequency stability for all intervals from as short as a single cycle to as long as days or months or more. Now with a 10 MHz standard we don't normally start an ADEV plot at a single (100 ns) cycle. But for 60 Hz it's perfectly natural to do so. A histogram of period is another way to show variations in cycle time. This gives more information than a single ADEV point. But to show variations as a function of averaging time, a whole set of separate histograms, or overlaid histograms, are required. It might be more accurate to put a flywheel on a synchronous motor and measure its speed, because the time constant of that system is a whole lot closer to that of the real grid frequency. I too was suspicious of digital or PLL or filtered methods of monitoring 60 Hz phase. To validate the digital methods I compared against an old synchronous wall clock. In the following animated GIF, a photo was taken exactly every 900 seconds (15 minutes): http://leapsecond.com/pages/tec/mains-clock-ani.gif It turns out the zero-crossing microprocessor digital time-stamping method exactly agreed with the old mechanical synchronous motor/inertia method. Satisfied with this result, I do all my mains phase/frequency logging using the digital time-stamp method (picPET). /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] WWVB
On Fri, Feb 22, 2013 at 06:01:46PM -0500, paul swed wrote: Donald from what I have been seeing they are consistent. But there is a 1 hour period up around 1 or 2 pm est that they go back to the old modulation and that allows time clocks to lock. Just for information here (from their web page): Since October 29, 2012 at 1500 UTC (9:00 AM MDT), NIST Radio Station WWVB has been broadcasting a phase modulation (PM) time code protocol that has been added to the legacy AM/pulse-width-modulation signal. This enhancement to the broadcast, which has been tested throughout 2012, provides significantly improved performance in new products that are designed to receive it. Existing radio-controlled clocks and watches are not affected by this enhancement, and continue to work as before. Disciplined oscillator products that track and lock to the 60 kHz WWVB carrier and were designed to work as frequency standards, will not work with the PM signal and will now become obsolete. A few radio controlled clocks that used information from the carrier – specifically the Spectracom NetClock and receivers manufactured by True Time during the 1970s and 1980s – will no longer be able to read the time code and will also be obsolete. To allow users of these receivers to migrate to new products, the plan for implementing the new modulation protocol includes a transition period that will extend until at least March 21, 2013. During the transition period, the PM signal will be turned off for 30 minutes twice per day, at noon and midnight Mountain Standard Time (MST), allowing carrier tracking receivers to temporarily acquire the legacy signal. HTC, Herbert At least thats what the spectracom 8170 does. Then it says its locked for a very long time even though it isn't. Regards Paul WB8TSL On Fri, Feb 22, 2013 at 3:35 PM, Donald Henderickx wa9...@sandprairie.netwrote: Is wwvb consistent in the testing of there modulation scheme?I find that My Spectracom 8182 will stay in time sync for several days,and then loose it for five or six hours. Is any one else experiencing this? I am thinking of trying my kinemetrics/truetime 60-TF to see if it might function. Don Henderickx __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://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] Logging the grid frequency....
All, If you want a reason for logging the mains frequency, see the following link to a news item which appeared on a BBC news program a few weeks ago here in the UK. http://www.bbc.co.uk/news/science-environment-20629671 There was also a full program about it which you can listen to at the following link http://www.bbc.co.uk/programmes/b01p7bxw John G3UUT On 23/02/2013 08:15, Tom Van Baak wrote: So it is not correct to measure one point to a gnat's nose hair and call it the grid frequency. Bill, Yes, and this is true for any source of frequency. That's why when we specify stability the averaging interval is critical; the x-axis of a log-log ADEV plot. One might look at every cycle to measure stuff like jitter, not so much to measure frequency over a tau of 0.016 seconds. The nice thing about ADEV is that a single plot can convey frequency stability for all intervals from as short as a single cycle to as long as days or months or more. Now with a 10 MHz standard we don't normally start an ADEV plot at a single (100 ns) cycle. But for 60 Hz it's perfectly natural to do so. A histogram of period is another way to show variations in cycle time. This gives more information than a single ADEV point. But to show variations as a function of averaging time, a whole set of separate histograms, or overlaid histograms, are required. It might be more accurate to put a flywheel on a synchronous motor and measure its speed, because the time constant of that system is a whole lot closer to that of the real grid frequency. I too was suspicious of digital or PLL or filtered methods of monitoring 60 Hz phase. To validate the digital methods I compared against an old synchronous wall clock. In the following animated GIF, a photo was taken exactly every 900 seconds (15 minutes): http://leapsecond.com/pages/tec/mains-clock-ani.gif It turns out the zero-crossing microprocessor digital time-stamping method exactly agreed with the old mechanical synchronous motor/inertia method. Satisfied with this result, I do all my mains phase/frequency logging using the digital time-stamp method (picPET). /tvb ___ time-nuts mailing list --time-nuts@febo.com To unsubscribe, go tohttps://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] WWVB
So, if you use phase-tracking hardware, it's good for three more weeks. Wonderful... not. :(( LORAN-C all over again! -John = On Fri, Feb 22, 2013 at 06:01:46PM -0500, paul swed wrote: Donald from what I have been seeing they are consistent. But there is a 1 hour period up around 1 or 2 pm est that they go back to the old modulation and that allows time clocks to lock. Just for information here (from their web page): Since October 29, 2012 at 1500 UTC (9:00 AM MDT), NIST Radio Station WWVB has been broadcasting a phase modulation (PM) time code protocol that has been added to the legacy AM/pulse-width-modulation signal. This enhancement to the broadcast, which has been tested throughout 2012, provides significantly improved performance in new products that are designed to receive it. Existing radio-controlled clocks and watches are not affected by this enhancement, and continue to work as before. Disciplined oscillator products that track and lock to the 60 kHz WWVB carrier and were designed to work as frequency standards, will not work with the PM signal and will now become obsolete. A few radio controlled clocks that used information from the carrier â specifically the Spectracom NetClock and receivers manufactured by True Time during the 1970s and 1980s â will no longer be able to read the time code and will also be obsolete. To allow users of these receivers to migrate to new products, the plan for implementing the new modulation protocol includes a transition period that will extend until at least March 21, 2013. During the transition period, the PM signal will be turned off for 30 minutes twice per day, at noon and midnight Mountain Standard Time (MST), allowing carrier tracking receivers to temporarily acquire the legacy signal. HTC, Herbert At least thats what the spectracom 8170 does. Then it says its locked for a very long time even though it isn't. Regards Paul WB8TSL On Fri, Feb 22, 2013 at 3:35 PM, Donald Henderickx wa9...@sandprairie.netwrote: Is wwvb consistent in the testing of there modulation scheme?I find that My Spectracom 8182 will stay in time sync for several days,and then loose it for five or six hours. Is any one else experiencing this? I am thinking of trying my kinemetrics/truetime 60-TF to see if it might function. Don Henderickx __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://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] WWVB
Now about those dead true-times. I am still looking for 1 or two to test with as I work on the WWVB d-PSK-r. I have shared one spectrcom solution with the group. And been working on a more universal costas loop answer. The loops seems to work nicely and has been operational over a two week period. Currently building a general purpose TRF front end for the loop. Johns put up with my emails through the year long process. Thanks. Regards Paul On Sat, Feb 23, 2013 at 9:37 AM, J. Forster j...@quikus.com wrote: So, if you use phase-tracking hardware, it's good for three more weeks. Wonderful... not. :(( LORAN-C all over again! -John = On Fri, Feb 22, 2013 at 06:01:46PM -0500, paul swed wrote: Donald from what I have been seeing they are consistent. But there is a 1 hour period up around 1 or 2 pm est that they go back to the old modulation and that allows time clocks to lock. Just for information here (from their web page): Since October 29, 2012 at 1500 UTC (9:00 AM MDT), NIST Radio Station WWVB has been broadcasting a phase modulation (PM) time code protocol that has been added to the legacy AM/pulse-width-modulation signal. This enhancement to the broadcast, which has been tested throughout 2012, provides significantly improved performance in new products that are designed to receive it. Existing radio-controlled clocks and watches are not affected by this enhancement, and continue to work as before. Disciplined oscillator products that track and lock to the 60 kHz WWVB carrier and were designed to work as frequency standards, will not work with the PM signal and will now become obsolete. A few radio controlled clocks that used information from the carrier – specifically the Spectracom NetClock and receivers manufactured by True Time during the 1970s and 1980s – will no longer be able to read the time code and will also be obsolete. To allow users of these receivers to migrate to new products, the plan for implementing the new modulation protocol includes a transition period that will extend until at least March 21, 2013. During the transition period, the PM signal will be turned off for 30 minutes twice per day, at noon and midnight Mountain Standard Time (MST), allowing carrier tracking receivers to temporarily acquire the legacy signal. HTC, Herbert At least thats what the spectracom 8170 does. Then it says its locked for a very long time even though it isn't. Regards Paul WB8TSL On Fri, Feb 22, 2013 at 3:35 PM, Donald Henderickx wa9...@sandprairie.netwrote: Is wwvb consistent in the testing of there modulation scheme?I find that My Spectracom 8182 will stay in time sync for several days,and then loose it for five or six hours. Is any one else experiencing this? I am thinking of trying my kinemetrics/truetime 60-TF to see if it might function. Don Henderickx __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nuts 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.
[time-nuts] Mems oscillators
Has anyone done any comparision between MEMS and quartz oscillators ? Is the long term stabilty (aging) of MEMS better than quartz ? ___ 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] Mems oscillators
Hi MEMS has the advantage of starting at a very high frequency. That lets you divide down and get pretty good broadband phase noise. That translates into good jitter performance over the normal telecom 12 KHz and up type of jitter masks. If you plan on putting in a very high shock / vibration environment (think 155mm projectiles) it will survive better than a chunk of quartz. Quartz has a higher resonator Q than MEMS and is rarely (if ever) seen in multiple resonator oscillator configurations. MEMS commonly shows up in multi resonator configurations. The lower Q means you will have worse close in phase noise on the MEMS. The multi-resonator stuff means the phase noise will get a bit nutty looking once you are inside the cluster of resonators (multiple peaks in the noise close to carrier). If your jitter requirement drives you to a mask with a low end limit below 100 Hz, the MEMS won't look very good for jitter compared to an XO. As you go lower still, an OCXO will look much better than either the XO or the MEMS. Aging wise, XO's are not something that people get real excited about aging on. If your $1 oscillator that is spec'd to 0.01% drifts 0.001% vs 0.0001% people rarely care. Not a lot of attention gets paid to that end of things. The same thing applies to MEMS. They are plenty good enough for the intended use. If you start looking at OCXO type aging, then no. MEMS is not going to do the same sort of 1.0x10^-10 per day / 1.0x10^-9 per month stuff that a modern chunk of quartz will do. Bob On Feb 23, 2013, at 12:07 PM, Darren Grist darren.gr...@gmail.com wrote: Has anyone done any comparision between MEMS and quartz oscillators ? Is the long term stabilty (aging) of MEMS better than quartz ? ___ 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] Logging the grid frequency....
Some grid connected inverters have a LOT of noise around the zero crossings, so much so that certain digital power meters won't function as they can't get frequency lock. I've seen this on the large Parker units as well as the low bid units out of China. So if you have solar or wind farm alternative energy projects nearby you may indeed see excessive noise. Excess noise and high order harmonics from such inverters has on occasion caused capacitive line filters on nearby equipment to overheat and catch fire. Peter On 2/23/2013 7:53 AM, Didier Juges wrote: I am curious how this compares with the zero crossing method. I suppose it should work much better because this method will not be so sensitive to noise around the zero crossings. It will use the entire waveform. Didier Sent from my Droid Razr 4G LTE wireless tracker. -Original Message- From: Gabs Ricalde gsrica...@gmail.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Fri, 22 Feb 2013 9:01 PM Subject: Re: [time-nuts] Logging the grid frequency Hello, I also don't have a Picotest or similar equipment but I've done similar things by using the line input of a soundcard. Multiply the recorded signal with a 60 Hz quadrature oscillator, apply a low pass filter then do some analysis on the resulting phasor. The stability of the sound card oscillator should be enough for this purpose. You can measure the frequency difference w.r.t. the 60 Hz oscillator by taking the slope of the phasor angle (be careful with phase wraparounds) and you can do this as often as you like. I'm curious how this compares with the zero crossing method. On Fri, Feb 22, 2013 at 8:46 PM, Daniel Mendes dmend...@gmail.com wrote: Hi, I have a Picotest U6200A. I´m trying to log the grid frequency (60Hz) to generate data for my work. I need to get data from every cycle. I setup their program (it always starts in chinese... very funny) but seems that it can only log every 100ms. Questions: 1) Is that a limitation of the equipment or the software? 2) Using direct comands, can I get data faster? Thanks for any help... Daniel ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ 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. - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1430 / Virus Database: 2639/5625 - Release Date: 02/23/13 ___ 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] Logging the grid frequency....
That was on my mind when I suggested a sampling phase comparator with the sampling time adjusted for noise rejection. Of course since I have been doing a lot of research recently on sampler design, every problem looks like a nail. :) Thyristor commutation into a reactive load can be nasty but I have heard horror stories about inverters as well. On Sat, 23 Feb 2013 14:05:36 -0500, Peter Gottlieb n...@verizon.net wrote: Some grid connected inverters have a LOT of noise around the zero crossings, so much so that certain digital power meters won't function as they can't get frequency lock. I've seen this on the large Parker units as well as the low bid units out of China. So if you have solar or wind farm alternative energy projects nearby you may indeed see excessive noise. Excess noise and high order harmonics from such inverters has on occasion caused capacitive line filters on nearby equipment to overheat and catch fire. Peter On 2/23/2013 7:53 AM, Didier Juges wrote: I am curious how this compares with the zero crossing method. I suppose it should work much better because this method will not be so sensitive to noise around the zero crossings. It will use the entire waveform. Didier Sent from my Droid Razr 4G LTE wireless tracker. -Original Message- From: Gabs Ricalde gsrica...@gmail.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Fri, 22 Feb 2013 9:01 PM Subject: Re: [time-nuts] Logging the grid frequency Hello, I also don't have a Picotest or similar equipment but I've done similar things by using the line input of a soundcard. Multiply the recorded signal with a 60 Hz quadrature oscillator, apply a low pass filter then do some analysis on the resulting phasor. The stability of the sound card oscillator should be enough for this purpose. You can measure the frequency difference w.r.t. the 60 Hz oscillator by taking the slope of the phasor angle (be careful with phase wraparounds) and you can do this as often as you like. I'm curious how this compares with the zero crossing method. ___ 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] Hello and new Project
Finally broke down and built a crossover Ethernet cable Manually setting my laptop to 192.168.56.100, I can connect to the TS2100L on 192.168.56.99 I was able to telnet to the TS2100 L and clear out the stray bits in the config that were not allowing me to config via the serial port. Appreciate the help from everyone! Martin Flynn On 2/23/2013 12:15 AM, Scott McGrath wrote: Ill see if I can dig up my manual for this used these units a few years ago Sent from my iPhone On Feb 22, 2013, at 9:10 PM, Martin A Flynn mafl...@theflynn.org wrote: Scott, Can you point me at the appropriate documentation so I can default the unit? Martin On 2/22/2013 1:06 PM, Scott McGrath wrote: Recommend doing a reset to default and configure as directed there are a lot of configurable options which can control access to this box ___ 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.
