Re: [time-nuts] What ALL of you Time Nuts really wants for Christmas!
I've got one David and for the price they do a reasonable job... I would strongly suggest that for an extra $ 200 you get the TG model ( DSA815TG ) that has the built in tracking generator.. I pretty much use mine for radio work and I would be lost without the tracking generator now... Cheers, Rob. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of David J Taylor Sent: Monday, 18 November 2013 5:25 PM To: time-nuts@febo.com Subject: Re: [time-nuts] What ALL of you Time Nuts really wants for Christmas! I'm considering a spectrum analyser with my pension lump sum cash: http://www.rigolna.com/products/spectrum-analyzers/dsa800/dsa815/ and perhaps an iPad Air: http://www.apple.com/uk/ipad-air/ More frequency than time, sorry! David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ 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] What ALL of you Time Nuts really wantsfor Christmas!
I've got one David and for the price they do a reasonable job... I would strongly suggest that for an extra $ 200 you get the TG model ( DSA815TG ) that has the built in tracking generator.. I pretty much use mine for radio work and I would be lost without the tracking generator now... Cheers, Rob. = Agreed, the TG option is a must. I don't have the room (or the weight-lifting strength) for one of the HP models you could likely get for the same money. G. David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ 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] national nc2001 atomic clock on eBay
On 18 November 2013 02:41, Bob Camp li...@rtty.us wrote: I have paid a lot of money over the years for “stuff”. I’m not in any way saying that buying “stuff” is a bad idea. If you could make it work, that’s certainly neat stuff. My only issue here is - what’s this going to do for somebody? The only sort of people I can see might be interested are historians, or anyone having some emotional attachment to it (e.g. they designed it). I find it hard to believe anyone in their right mind would buy it with the intension of restoring it so they have a workable frequency source. There are some interesting auctions on eBay. This was one of my all time favouries, although for some reasons I have put the pages of the PDF file in revese order http://www.g8wrb.org/useful-stuff/pdf/bad-amplifier.pdf Anyone know a quick way of reversing the order of the pages in a document? Dave ___ 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] national nc2001 atomic clock on eBay
Extract and rebuild in Acrobat... on it's way back to you:-) Regards Nigel GM8PZR In a message dated 18/11/2013 09:44:38 GMT Standard Time, drkir...@gmail.com writes: Anyone know a quick way of reversing the order of the pages in a document? ___ 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] What happened tohttp://tf.nist.gov/timefreq/general/pdf ?
Hi Tom, Thanks for checking this for me. From where I am I most definitely cannot access the web site - it keeps timing out. But, when I use an online proxy server it works fine. A bit of a hack, but luckily I can still access the material. Cheers, Stephan On 16 November 2013 16:18, Tom Van Baak t...@leapsecond.com wrote: Stephan, Try again. It looks ok to me. Test with: http://tf.boulder.nist.gov/general/pdf/1.pdf You can also use the search page: http://tf.nist.gov/timefreq/general/publications.htm /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. ___ 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] national nc2001 atomic clock on eBay
The description made it sound much worse than it was though. I've seen brassboards of ultimately highly successful products which were far worse than that. On 11/18/2013 4:39 AM, Dr. David Kirkby wrote: On 18 November 2013 02:41, Bob Camp li...@rtty.us wrote: I have paid a lot of money over the years for “stuff”. I’m not in any way saying that buying “stuff” is a bad idea. If you could make it work, that’s certainly neat stuff. My only issue here is - what’s this going to do for somebody? The only sort of people I can see might be interested are historians, or anyone having some emotional attachment to it (e.g. they designed it). I find it hard to believe anyone in their right mind would buy it with the intension of restoring it so they have a workable frequency source. There are some interesting auctions on eBay. This was one of my all time favouries, although for some reasons I have put the pages of the PDF file in revese order http://www.g8wrb.org/useful-stuff/pdf/bad-amplifier.pdf Anyone know a quick way of reversing the order of the pages in a document? Dave ___ 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] national nc2001 atomic clock on eBay
Bob Pease was famous for this. https://www.google.com/search?q=bob+pease+desktbm=ischtbo=usource=univsa =Xei=HkeKUrflDImdiQKnk4C4Agsqi=2ved=0CCoQsAQbiw=2133bih=1239 http://www.philbrickarchive.org/rap.htm http://www.eetimes.com/author.asp?section_id=28doc_id=1285208 http://www.ti.com/ww/en/bobpease/index.html (big PDF of his writings and engeneering) -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Peter Gottlieb Sent: Monday, November 18, 2013 05:09 To: time-nuts@febo.com Subject: Re: [time-nuts] national nc2001 atomic clock on eBay The description made it sound much worse than it was though. I've seen brassboards of ultimately highly successful products which were far worse than that. On 11/18/2013 4:39 AM, Dr. David Kirkby wrote: On 18 November 2013 02:41, Bob Camp li...@rtty.us wrote: I have paid a lot of money over the years for stuff. I'm not in any way saying that buying stuff is a bad idea. If you could make it work, that's certainly neat stuff. My only issue here is - what's this going to do for somebody? The only sort of people I can see might be interested are historians, or anyone having some emotional attachment to it (e.g. they designed it). I find it hard to believe anyone in their right mind would buy it with the intension of restoring it so they have a workable frequency source. There are some interesting auctions on eBay. This was one of my all time favouries, although for some reasons I have put the pages of the PDF file in revese order http://www.g8wrb.org/useful-stuff/pdf/bad-amplifier.pdf Anyone know a quick way of reversing the order of the pages in a document? Dave ___ 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] LFphoenix still on since last week.
This is one of the longest runs I have seen in a long time. Regards Paul WB8TSL Boston ___ 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] Mains frequency
Magnus, I'm going to push back a bit on your mains sampling claim. Mostly, I'd like to see the results of the professional I-Q demodulated gear that you mentioned. Can you post raw data, or a sample plot? I agree that looking at power line voltage with 16- or 24-bits at 1 Msps is going to reveal interesting amplitude and phase noise information. But see how well a $1 PIC can do. Attached is a plot made using TimeLab + picPET just now. The picPET is fast enough to capture the zero-crossing of every 60 Hz cycle with 400 ns resolution; the TimeLab plots have tau0 of 16.67 ms. -- The blue trace was simply plugging a 9 VAC wall-wart into the picPET though a 10k resistor. -- The pink trace was adding a 10 nF cap across the input. -- The green trace was unplugging my laptop switching power supply from the same outlet! -- The red trace is replacing the mains wall-wart with a hp 33120A set to 9VAC at 60 Hz, a tentative noise floor measurement of the picPET when used this way. My conclusions are that at least here in the US, or at least at my house, the short-term stability of mains hits about 5e-6, at about tau 0.2 seconds. The attached short-term plot is also not-inconsistent with the long-term plot at http://leapsecond.com/pages/mains/ My other conclusion is that the picPET (a simple PIC-based time-stamping counter) is doing a pretty good job measuring this. Note, no software or data filtering was used. This is just raw serial/USB data going into TimeLab. /tvb attachment: mains-picpet-04.gif___ 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] Mains frequency
Hi Let’s hope Santa does not bring you an X10 power line based remote control system for Christmas…. Bob On Nov 18, 2013, at 5:15 PM, Tom Van Baak t...@leapsecond.com wrote: Magnus, I'm going to push back a bit on your mains sampling claim. Mostly, I'd like to see the results of the professional I-Q demodulated gear that you mentioned. Can you post raw data, or a sample plot? I agree that looking at power line voltage with 16- or 24-bits at 1 Msps is going to reveal interesting amplitude and phase noise information. But see how well a $1 PIC can do. Attached is a plot made using TimeLab + picPET just now. The picPET is fast enough to capture the zero-crossing of every 60 Hz cycle with 400 ns resolution; the TimeLab plots have tau0 of 16.67 ms. -- The blue trace was simply plugging a 9 VAC wall-wart into the picPET though a 10k resistor. -- The pink trace was adding a 10 nF cap across the input. -- The green trace was unplugging my laptop switching power supply from the same outlet! -- The red trace is replacing the mains wall-wart with a hp 33120A set to 9VAC at 60 Hz, a tentative noise floor measurement of the picPET when used this way. My conclusions are that at least here in the US, or at least at my house, the short-term stability of mains hits about 5e-6, at about tau 0.2 seconds. The attached short-term plot is also not-inconsistent with the long-term plot at http://leapsecond.com/pages/mains/ My other conclusion is that the picPET (a simple PIC-based time-stamping counter) is doing a pretty good job measuring this. Note, no software or data filtering was used. This is just raw serial/USB data going into TimeLab. /tvb mains-picpet-04.gif___ 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] Mains frequency
Tom, Don't confuse everybody with facts, we had a good thread going :) The PicPet is holding its own very well in that application. I am surprised at the effect of the laptop supply. I would have certainly expected effect on phase noise (smaller taus), but not that close to the carrier. Do you know if it is a power factor corrected supply or not? Didier KO4BB Tom Van Baak t...@leapsecond.com wrote: Magnus, I'm going to push back a bit on your mains sampling claim. Mostly, I'd like to see the results of the professional I-Q demodulated gear that you mentioned. Can you post raw data, or a sample plot? I agree that looking at power line voltage with 16- or 24-bits at 1 Msps is going to reveal interesting amplitude and phase noise information. But see how well a $1 PIC can do. Attached is a plot made using TimeLab + picPET just now. The picPET is fast enough to capture the zero-crossing of every 60 Hz cycle with 400 ns resolution; the TimeLab plots have tau0 of 16.67 ms. -- The blue trace was simply plugging a 9 VAC wall-wart into the picPET though a 10k resistor. -- The pink trace was adding a 10 nF cap across the input. -- The green trace was unplugging my laptop switching power supply from the same outlet! -- The red trace is replacing the mains wall-wart with a hp 33120A set to 9VAC at 60 Hz, a tentative noise floor measurement of the picPET when used this way. My conclusions are that at least here in the US, or at least at my house, the short-term stability of mains hits about 5e-6, at about tau 0.2 seconds. The attached short-term plot is also not-inconsistent with the long-term plot at http://leapsecond.com/pages/mains/ My other conclusion is that the picPET (a simple PIC-based time-stamping counter) is doing a pretty good job measuring this. Note, no software or data filtering was used. This is just raw serial/USB data going into TimeLab. /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. -- Sent from my Motorola Droid Razr 4G LTE wireless tracker while I do other things. ___ 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] Mains frequency
tom, nice plots. how do you figure out what the contribution of variability vs noise? In other words there is a differential between the ideal and the actual a dev curves... is there a way to tease out how much nose contribute to that differential? It does seem to me that there should be far less short term variability ( 100s) than there appears to be. Clearly in the very short tau ( 0.1 s) the picPET can't tease that out but as the curves diverge, how much of that is noise? between say 0.1s and 100s? Being a power plant operator I would say quite a bit although I am rethinking that some due to the way the turbines push and pull each other. I can envision some fine whole grid oscillations due to that push and pull. bill On Mon, Nov 18, 2013 at 4:15 PM, Tom Van Baak t...@leapsecond.com wrote: Magnus, I'm going to push back a bit on your mains sampling claim. Mostly, I'd like to see the results of the professional I-Q demodulated gear that you mentioned. Can you post raw data, or a sample plot? I agree that looking at power line voltage with 16- or 24-bits at 1 Msps is going to reveal interesting amplitude and phase noise information. But see how well a $1 PIC can do. Attached is a plot made using TimeLab + picPET just now. The picPET is fast enough to capture the zero-crossing of every 60 Hz cycle with 400 ns resolution; the TimeLab plots have tau0 of 16.67 ms. -- The blue trace was simply plugging a 9 VAC wall-wart into the picPET though a 10k resistor. -- The pink trace was adding a 10 nF cap across the input. -- The green trace was unplugging my laptop switching power supply from the same outlet! -- The red trace is replacing the mains wall-wart with a hp 33120A set to 9VAC at 60 Hz, a tentative noise floor measurement of the picPET when used this way. My conclusions are that at least here in the US, or at least at my house, the short-term stability of mains hits about 5e-6, at about tau 0.2 seconds. The attached short-term plot is also not-inconsistent with the long-term plot at http://leapsecond.com/pages/mains/ My other conclusion is that the picPET (a simple PIC-based time-stamping counter) is doing a pretty good job measuring this. Note, no software or data filtering was used. This is just raw serial/USB data going into TimeLab. /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. -- Doc Bill Dailey KXØO ___ 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] Mains frequency
Hi An “ideal” curve would go to the bottom of the scale as soon as the plot started. Anything that shows on the ADEV curve is by definition noise. The slope of the ADEV curve can help you determine what sort of noise it is. The slope(s) on an modified ADEV curve can do that slightly better. Bob On Nov 18, 2013, at 8:03 PM, Bill Dailey docdai...@gmail.com wrote: tom, nice plots. how do you figure out what the contribution of variability vs noise? In other words there is a differential between the ideal and the actual a dev curves... is there a way to tease out how much nose contribute to that differential? It does seem to me that there should be far less short term variability ( 100s) than there appears to be. Clearly in the very short tau ( 0.1 s) the picPET can't tease that out but as the curves diverge, how much of that is noise? between say 0.1s and 100s? Being a power plant operator I would say quite a bit although I am rethinking that some due to the way the turbines push and pull each other. I can envision some fine whole grid oscillations due to that push and pull. bill On Mon, Nov 18, 2013 at 4:15 PM, Tom Van Baak t...@leapsecond.com wrote: Magnus, I'm going to push back a bit on your mains sampling claim. Mostly, I'd like to see the results of the professional I-Q demodulated gear that you mentioned. Can you post raw data, or a sample plot? I agree that looking at power line voltage with 16- or 24-bits at 1 Msps is going to reveal interesting amplitude and phase noise information. But see how well a $1 PIC can do. Attached is a plot made using TimeLab + picPET just now. The picPET is fast enough to capture the zero-crossing of every 60 Hz cycle with 400 ns resolution; the TimeLab plots have tau0 of 16.67 ms. -- The blue trace was simply plugging a 9 VAC wall-wart into the picPET though a 10k resistor. -- The pink trace was adding a 10 nF cap across the input. -- The green trace was unplugging my laptop switching power supply from the same outlet! -- The red trace is replacing the mains wall-wart with a hp 33120A set to 9VAC at 60 Hz, a tentative noise floor measurement of the picPET when used this way. My conclusions are that at least here in the US, or at least at my house, the short-term stability of mains hits about 5e-6, at about tau 0.2 seconds. The attached short-term plot is also not-inconsistent with the long-term plot at http://leapsecond.com/pages/mains/ My other conclusion is that the picPET (a simple PIC-based time-stamping counter) is doing a pretty good job measuring this. Note, no software or data filtering was used. This is just raw serial/USB data going into TimeLab. /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. -- Doc Bill Dailey KXØO ___ 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] Mains frequency
I meant ideal at the noise floor of the picPET (i.e in this case the generated 60Hz). On Mon, Nov 18, 2013 at 8:08 PM, Bob Camp li...@rtty.us wrote: Hi An “ideal” curve would go to the bottom of the scale as soon as the plot started. Anything that shows on the ADEV curve is by definition noise. The slope of the ADEV curve can help you determine what sort of noise it is. The slope(s) on an modified ADEV curve can do that slightly better. Bob On Nov 18, 2013, at 8:03 PM, Bill Dailey docdai...@gmail.com wrote: tom, nice plots. how do you figure out what the contribution of variability vs noise? In other words there is a differential between the ideal and the actual a dev curves... is there a way to tease out how much nose contribute to that differential? It does seem to me that there should be far less short term variability ( 100s) than there appears to be. Clearly in the very short tau ( 0.1 s) the picPET can't tease that out but as the curves diverge, how much of that is noise? between say 0.1s and 100s? Being a power plant operator I would say quite a bit although I am rethinking that some due to the way the turbines push and pull each other. I can envision some fine whole grid oscillations due to that push and pull. bill On Mon, Nov 18, 2013 at 4:15 PM, Tom Van Baak t...@leapsecond.com wrote: Magnus, I'm going to push back a bit on your mains sampling claim. Mostly, I'd like to see the results of the professional I-Q demodulated gear that you mentioned. Can you post raw data, or a sample plot? I agree that looking at power line voltage with 16- or 24-bits at 1 Msps is going to reveal interesting amplitude and phase noise information. But see how well a $1 PIC can do. Attached is a plot made using TimeLab + picPET just now. The picPET is fast enough to capture the zero-crossing of every 60 Hz cycle with 400 ns resolution; the TimeLab plots have tau0 of 16.67 ms. -- The blue trace was simply plugging a 9 VAC wall-wart into the picPET though a 10k resistor. -- The pink trace was adding a 10 nF cap across the input. -- The green trace was unplugging my laptop switching power supply from the same outlet! -- The red trace is replacing the mains wall-wart with a hp 33120A set to 9VAC at 60 Hz, a tentative noise floor measurement of the picPET when used this way. My conclusions are that at least here in the US, or at least at my house, the short-term stability of mains hits about 5e-6, at about tau 0.2 seconds. The attached short-term plot is also not-inconsistent with the long-term plot at http://leapsecond.com/pages/mains/ My other conclusion is that the picPET (a simple PIC-based time-stamping counter) is doing a pretty good job measuring this. Note, no software or data filtering was used. This is just raw serial/USB data going into TimeLab. /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. -- Doc Bill Dailey KXØO ___ 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. -- Doc Bill Dailey KXØO ___ 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] Mains frequency
The power supply contribution is interesting. This might have been a useful tool when a year ago I was playing with some very large inverters on a microgrid. I had one inverter as master (in UF mode) and two others as grid-connected slaves in PQ mode. The first slave would come online just fine yet when the second was synched the entire microgrid would go unstable. It was noise at the zero crossings but not enough to see on a scope. With all the distributed generation coming online I would be wary of relying on those zero crossings. Peter On 11/18/2013 5:15 PM, Tom Van Baak wrote: Magnus, I'm going to push back a bit on your mains sampling claim. Mostly, I'd like to see the results of the professional I-Q demodulated gear that you mentioned. Can you post raw data, or a sample plot? I agree that looking at power line voltage with 16- or 24-bits at 1 Msps is going to reveal interesting amplitude and phase noise information. But see how well a $1 PIC can do. Attached is a plot made using TimeLab + picPET just now. The picPET is fast enough to capture the zero-crossing of every 60 Hz cycle with 400 ns resolution; the TimeLab plots have tau0 of 16.67 ms. -- The blue trace was simply plugging a 9 VAC wall-wart into the picPET though a 10k resistor. -- The pink trace was adding a 10 nF cap across the input. -- The green trace was unplugging my laptop switching power supply from the same outlet! -- The red trace is replacing the mains wall-wart with a hp 33120A set to 9VAC at 60 Hz, a tentative noise floor measurement of the picPET when used this way. My conclusions are that at least here in the US, or at least at my house, the short-term stability of mains hits about 5e-6, at about tau 0.2 seconds. The attached short-term plot is also not-inconsistent with the long-term plot at http://leapsecond.com/pages/mains/ My other conclusion is that the picPET (a simple PIC-based time-stamping counter) is doing a pretty good job measuring this. Note, no software or data filtering was used. This is just raw serial/USB data going into TimeLab. /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. ___ 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] Mains frequency
Hi There is no way to come up with the noise floor of the picPET from that plot. In fact coming up with the floor of a single channel device like the picPET is not all that easy. First you need an ideal noise free sine wave signal …. I’ve spent more than a few hours on that particular project with other list members involved as well. As always we kept it off list to keep from offending those who place a high value on their bandwidth. Bob On Nov 18, 2013, at 9:11 PM, Bill Dailey docdai...@gmail.com wrote: I meant ideal at the noise floor of the picPET (i.e in this case the generated 60Hz). On Mon, Nov 18, 2013 at 8:08 PM, Bob Camp li...@rtty.us wrote: Hi An “ideal” curve would go to the bottom of the scale as soon as the plot started. Anything that shows on the ADEV curve is by definition noise. The slope of the ADEV curve can help you determine what sort of noise it is. The slope(s) on an modified ADEV curve can do that slightly better. Bob On Nov 18, 2013, at 8:03 PM, Bill Dailey docdai...@gmail.com wrote: tom, nice plots. how do you figure out what the contribution of variability vs noise? In other words there is a differential between the ideal and the actual a dev curves... is there a way to tease out how much nose contribute to that differential? It does seem to me that there should be far less short term variability ( 100s) than there appears to be. Clearly in the very short tau ( 0.1 s) the picPET can't tease that out but as the curves diverge, how much of that is noise? between say 0.1s and 100s? Being a power plant operator I would say quite a bit although I am rethinking that some due to the way the turbines push and pull each other. I can envision some fine whole grid oscillations due to that push and pull. bill On Mon, Nov 18, 2013 at 4:15 PM, Tom Van Baak t...@leapsecond.com wrote: Magnus, I'm going to push back a bit on your mains sampling claim. Mostly, I'd like to see the results of the professional I-Q demodulated gear that you mentioned. Can you post raw data, or a sample plot? I agree that looking at power line voltage with 16- or 24-bits at 1 Msps is going to reveal interesting amplitude and phase noise information. But see how well a $1 PIC can do. Attached is a plot made using TimeLab + picPET just now. The picPET is fast enough to capture the zero-crossing of every 60 Hz cycle with 400 ns resolution; the TimeLab plots have tau0 of 16.67 ms. -- The blue trace was simply plugging a 9 VAC wall-wart into the picPET though a 10k resistor. -- The pink trace was adding a 10 nF cap across the input. -- The green trace was unplugging my laptop switching power supply from the same outlet! -- The red trace is replacing the mains wall-wart with a hp 33120A set to 9VAC at 60 Hz, a tentative noise floor measurement of the picPET when used this way. My conclusions are that at least here in the US, or at least at my house, the short-term stability of mains hits about 5e-6, at about tau 0.2 seconds. The attached short-term plot is also not-inconsistent with the long-term plot at http://leapsecond.com/pages/mains/ My other conclusion is that the picPET (a simple PIC-based time-stamping counter) is doing a pretty good job measuring this. Note, no software or data filtering was used. This is just raw serial/USB data going into TimeLab. /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. -- Doc Bill Dailey KXØO ___ 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. -- Doc Bill Dailey KXØO ___ 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] Mains frequency
ok Bob, Then how do you tease out the difference between the clean generated 60Hz and the mains 60Hz adev curves to determine what is noise and what is the variability in the 60Hz? That is the point of my question not semantics about ideal vs non-ideal. doc On Mon, Nov 18, 2013 at 8:36 PM, Bob Camp li...@rtty.us wrote: Hi There is no way to come up with the noise floor of the picPET from that plot. In fact coming up with the floor of a single channel device like the picPET is not all that easy. First you need an ideal noise free sine wave signal …. I’ve spent more than a few hours on that particular project with other list members involved as well. As always we kept it off list to keep from offending those who place a high value on their bandwidth. Bob On Nov 18, 2013, at 9:11 PM, Bill Dailey docdai...@gmail.com wrote: I meant ideal at the noise floor of the picPET (i.e in this case the generated 60Hz). On Mon, Nov 18, 2013 at 8:08 PM, Bob Camp li...@rtty.us wrote: Hi An “ideal” curve would go to the bottom of the scale as soon as the plot started. Anything that shows on the ADEV curve is by definition noise. The slope of the ADEV curve can help you determine what sort of noise it is. The slope(s) on an modified ADEV curve can do that slightly better. Bob On Nov 18, 2013, at 8:03 PM, Bill Dailey docdai...@gmail.com wrote: tom, nice plots. how do you figure out what the contribution of variability vs noise? In other words there is a differential between the ideal and the actual a dev curves... is there a way to tease out how much nose contribute to that differential? It does seem to me that there should be far less short term variability ( 100s) than there appears to be. Clearly in the very short tau ( 0.1 s) the picPET can't tease that out but as the curves diverge, how much of that is noise? between say 0.1s and 100s? Being a power plant operator I would say quite a bit although I am rethinking that some due to the way the turbines push and pull each other. I can envision some fine whole grid oscillations due to that push and pull. bill On Mon, Nov 18, 2013 at 4:15 PM, Tom Van Baak t...@leapsecond.com wrote: Magnus, I'm going to push back a bit on your mains sampling claim. Mostly, I'd like to see the results of the professional I-Q demodulated gear that you mentioned. Can you post raw data, or a sample plot? I agree that looking at power line voltage with 16- or 24-bits at 1 Msps is going to reveal interesting amplitude and phase noise information. But see how well a $1 PIC can do. Attached is a plot made using TimeLab + picPET just now. The picPET is fast enough to capture the zero-crossing of every 60 Hz cycle with 400 ns resolution; the TimeLab plots have tau0 of 16.67 ms. -- The blue trace was simply plugging a 9 VAC wall-wart into the picPET though a 10k resistor. -- The pink trace was adding a 10 nF cap across the input. -- The green trace was unplugging my laptop switching power supply from the same outlet! -- The red trace is replacing the mains wall-wart with a hp 33120A set to 9VAC at 60 Hz, a tentative noise floor measurement of the picPET when used this way. My conclusions are that at least here in the US, or at least at my house, the short-term stability of mains hits about 5e-6, at about tau 0.2 seconds. The attached short-term plot is also not-inconsistent with the long-term plot at http://leapsecond.com/pages/mains/ My other conclusion is that the picPET (a simple PIC-based time-stamping counter) is doing a pretty good job measuring this. Note, no software or data filtering was used. This is just raw serial/USB data going into TimeLab. /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. -- Doc Bill Dailey KXØO ___ 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. -- Doc Bill Dailey KXØO ___ 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. -- Doc
