Re: [time-nuts] Dual Mixer
Bruce Good, It does seem like we are finally making some good progress. You now seem to acknowledge that my tester could work if I integrate. You now seem to acknowledge that I am integrating by using a filter. I acknowledge that my integration method is not perfect, BUT it is simple and good enough. It would seem the only issue left is to show you just how good of answers my integration method gives. At least now we are JUST talking about what the S/W needs to do. Hopefully you now see that the hardware is adequate. What would you consider an acceptable error band, 3 dB, 1 dB, 0.1 dB? Pick a number zero. For a typical high speed data log taken at say 1 K samples per second, one would generally run a quick test with maybe a minute's worth of data. That would provide enough data to give a good tau plot up to about 10 seconds. Now if you can supply me with a 60K data log with any type of reasonably typical noise that you want to include in it I'll show you how close my approximate Integration comes to your perfect integration. I can set this up to do as many times as you want, until I have demonstrated by example that it is close enough, for every data log case that you will provide. Near enough IS good enough for me and most Nuts. As John pointed out, this is measuring noise. One is not going to get the exact same answer twice in a row anyway. My answer will not be perfect, but it will be simple and fast and easy and below the noise uncertainty band. Your turn to put a data log where your math is. Do try and remember I'm working with Frequency and not phase. BTW. just a heads-up warning to be fair. I have set up this situation so that I can not loose. If you want to setup your own situation go for it. I'll see if I can do it. Only requirement is that it should be broken down into no more than 60K sample sizes max for each test at the start. After I pass that, if you want to go for millions of samples or whatever, fine as long as I can read the text data log file. ws - Original Message - From: Bruce Griffiths bruce.griffi...@xtra.co.nz To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Tuesday, May 11, 2010 9:12 PM Subject: Re: [time-nuts] Dual Mixer Warren Calculating an integral using a sampled data system when the Nyquist criterion is met is exactly equivalent to filtering albeit using just the right coefficients. Using rectangular approximation to the integral of the underlying continuous function is also equivalent to a filter albeit a very simple one. Unfortunately rectangular integration (which you use) isnt particularly accurate, using trapezoidal integration is far more accurate in most cases. Since this isnt a control system the instability associated with trapezoidal integration and higher order integration algorithms in feedback systems isnt an issue. Whittaker-Shannon-Kotelnikov interpolation allows an exact reconstruction (when the Nyquist sampling criterion is met) of the underlying continuous function from the samples. The result can then be integrated term by term to produce a set of weights/filter coefficients for the data samples. In other words in a sampled data system integration is equivalent to using a filter. Near enough is never good enough if you can't estimate the errors involved in the various approximations. This is particularly true when one is attempting to evaluate the deviation of an approximate method from that achieved using the correct method. Bruce * WarrenS wrote: Bruce So why are you saying I need millions of samples? Is it that this method of integration may give the wrong answer one out a million times? And you will not let up until you find that one in a million times that it may error? I don't think you're going to find it, but if you want we can go with that. BTW It does NOT need ANY scale factors, special or otherwise to give the right answers. It uses the same scale factor of ONE for ALL noise sources. If you can't give me an example of a data log that it may fail on, that I can run thru excel to prove otherwise, then We're done here until next time. ws *** * The results have so far only been shown to be useful when white phase noise dominates. When the phase noise is white almost anything can be made to produce a result that differs from ADEV by at scale factor. In practice its sometimes difficult to know over what range of Tau that the phase noise is in fact white. The various tests and comparisons that have been made or are underway are necessary but not sufficient proof of the usefulness of this technique. The phase noise frequency response of the technique is also required so that its limitations can be delineated. 1000 samples of a divergent noise process are insufficient, spreadsheet analysis of the millions of samples that are probably necessary is
[time-nuts] synchronizing a large number of weakly coupled oscillators
Has anyone utilized a network of locally, weakly coupled oscillator synchronization (a la http://www.projectcomputing.com/resources/sync/index.html ) for precise timekeeping purposes? -- Eugen* Leitl a href=http://leitl.org;leitl/a http://leitl.org __ ICBM: 48.07100, 11.36820 http://www.ativel.com http://postbiota.org 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE ___ 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] Dual Mixer
WarrenS wrote: Bruce Good, It does seem like we are finally making some good progress. You now seem to acknowledge that my tester could work if I integrate. You now seem to acknowledge that I am integrating by using a filter. In a sampled data system integration is equivalent to a filter but not just any arbitrary low pass filter. The errors in your method are explicitly spelled out in the paper I gave the link to: http://hal.archives-ouvertes.fr/docs/00/37/63/05/PDF/alaa_p1_v4a.pdf In this paper xi is a phase sample and yi is a frequency sample. I acknowledge that my integration method is not perfect, BUT it is simple and good enough. Not yet proven nor quantified. It would seem the only issue left is to show you just how good of answers my integration method gives. At least now we are JUST talking about what the S/W needs to do. Hopefully you now see that the hardware is adequate. What would you consider an acceptable error band, 3 dB, 1 dB, 0.1 dB? Pick a number zero. The answer depends on how long one is willing to spend making the measurements. Certainly 0.1dB or better would require heroic efforts to demonstrate. Since the error will also depend on the phase noise spectra of the oscillators being compared a single figure answer isnt feasible. However for the case where white phase noise dominates the error should be not more than 1dB but potentially much less. The errors due to digital signal processing should be at least an order of magnitude lower. For a typical high speed data log taken at say 1 K samples per second, one would generally run a quick test with maybe a minute's worth of data. That would provide enough data to give a good tau plot up to about 10 seconds. That's a rather sweeping statement given that no estimates of the contribution to measurement noise due to the finite number of samples has been made. The maximum usable tau for a given record length depends on the maximum acceptable error due to the finite number of samples. Now if you can supply me with a 60K data log with any type of reasonably typical noise that you want to include in it I'll show you how close my approximate Integration comes to your perfect integration. You can't because your method of perfect integration isnt and its errors cannot be made sufficiently small with so few samples. I can set this up to do as many times as you want, until I have demonstrated by example that it is close enough, for every data log case that you will provide. Near enough IS good enough for me and most Nuts. Quantify near enough else all is just noise. As John pointed out, this is measuring noise. One is not going to get the exact same answer twice in a row anyway. My answer will not be perfect, but it will be simple and fast and easy and below the noise uncertainty band. Your turn to put a data log where your math is. Do try and remember I'm working with Frequency and not phase. Thats idle speculation as you havent quantified anything at all. The repeatability of the measurements needs to be quantified. BTW. just a heads-up warning to be fair. I have set up this situation so that I can not loose. Its actually almost trivial to produce a set of samples for which any given method will fail. Doing so is an unproductive exercise. If you want to setup your own situation go for it. I'll see if I can do it. Only requirement is that it should be broken down into no more than 60K sample sizes max for each test at the start. After I pass that, if you want to go for millions of samples or whatever, fine as long as I can read the text data log file. ws Bruce ___ 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] Dual Mixer
Sounds like someone is grandstanding to me! Steve On 12 May 2010 22:26, Bruce Griffiths bruce.griffi...@xtra.co.nz wrote: WarrenS wrote: Bruce Good, It does seem like we are finally making some good progress. You now seem to acknowledge that my tester could work if I integrate. You now seem to acknowledge that I am integrating by using a filter. In a sampled data system integration is equivalent to a filter but not just any arbitrary low pass filter. The errors in your method are explicitly spelled out in the paper I gave the link to: http://hal.archives-ouvertes.fr/docs/00/37/63/05/PDF/alaa_p1_v4a.pdf In this paper xi is a phase sample and yi is a frequency sample. I acknowledge that my integration method is not perfect, BUT it is simple and good enough. Not yet proven nor quantified. It would seem the only issue left is to show you just how good of answers my integration method gives. At least now we are JUST talking about what the S/W needs to do. Hopefully you now see that the hardware is adequate. What would you consider an acceptable error band, 3 dB, 1 dB, 0.1 dB? Pick a number zero. The answer depends on how long one is willing to spend making the measurements. Certainly 0.1dB or better would require heroic efforts to demonstrate. Since the error will also depend on the phase noise spectra of the oscillators being compared a single figure answer isnt feasible. However for the case where white phase noise dominates the error should be not more than 1dB but potentially much less. The errors due to digital signal processing should be at least an order of magnitude lower. For a typical high speed data log taken at say 1 K samples per second, one would generally run a quick test with maybe a minute's worth of data. That would provide enough data to give a good tau plot up to about 10 seconds. That's a rather sweeping statement given that no estimates of the contribution to measurement noise due to the finite number of samples has been made. The maximum usable tau for a given record length depends on the maximum acceptable error due to the finite number of samples. Now if you can supply me with a 60K data log with any type of reasonably typical noise that you want to include in it I'll show you how close my approximate Integration comes to your perfect integration. You can't because your method of perfect integration isnt and its errors cannot be made sufficiently small with so few samples. I can set this up to do as many times as you want, until I have demonstrated by example that it is close enough, for every data log case that you will provide. Near enough IS good enough for me and most Nuts. Quantify near enough else all is just noise. As John pointed out, this is measuring noise. One is not going to get the exact same answer twice in a row anyway. My answer will not be perfect, but it will be simple and fast and easy and below the noise uncertainty band. Your turn to put a data log where your math is. Do try and remember I'm working with Frequency and not phase. Thats idle speculation as you havent quantified anything at all. The repeatability of the measurements needs to be quantified. BTW. just a heads-up warning to be fair. I have set up this situation so that I can not loose. Its actually almost trivial to produce a set of samples for which any given method will fail. Doing so is an unproductive exercise. If you want to setup your own situation go for it. I'll see if I can do it. Only requirement is that it should be broken down into no more than 60K sample sizes max for each test at the start. After I pass that, if you want to go for millions of samples or whatever, fine as long as I can read the text data log file. ws Bruce ___ 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. -- Steve Rooke - ZL3TUV G8KVD A man with one clock knows what time it is; A man with two clocks is never quite sure. ___ 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] synchronizing a large number of weakly coupled oscillators
Hi The tendency of clocks to self synchronize dates back at least to the days of pendulum clocks. It may date to the era of water clocks, but if so it's undocumented. It has been observed on a wide range of modern clock designs. If you look into injection locking you'll get a pretty good picture of what's going on. The whole injection locking debate has gone on many times here on this list. Some think it's a good idea, others are not as excited about it. I am not aware of anybody using injection locking in precision applications. Normally the requirements on a precision clock include filtering that are difficult to do with an injection lock approach. Bob On May 12, 2010, at 2:47 AM, Eugen Leitl wrote: Has anyone utilized a network of locally, weakly coupled oscillator synchronization (a la http://www.projectcomputing.com/resources/sync/index.html ) for precise timekeeping purposes? -- Eugen* Leitl a href=http://leitl.org;leitl/a http://leitl.org __ ICBM: 48.07100, 11.36820 http://www.ativel.com http://postbiota.org 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE ___ 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] synchronizing a large number of weakly coupled oscillators
Eugen Leitl wrote: Has anyone utilized a network of locally, weakly coupled oscillator synchronization (a la http://www.projectcomputing.com/resources/sync/index.html ) for precise timekeeping purposes? There was a discussion on this list about doing something like filling a cavern with pendulums in this connection a couple months ago. Bob York at UCSB and Ron Pogorzelski, a recently retired colleague of mine at JPL, hav done a lot of work with coupled oscillator arrays. They're used as a way to do phased array antennas. googling coupled oscillator array will turn up many hits. Allan had a paper where he had 8 inexpensive crystals coupled with mixers and a microcontroller. I think it's called the Clever Temperature Compensated XO or something like that. ___ 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] synchronizing a large number of weakly coupled oscillators
On Wed, May 12, 2010 at 06:03:11AM -0700, jimlux wrote: Eugen Leitl wrote: Has anyone utilized a network of locally, weakly coupled oscillator synchronization (a la http://www.projectcomputing.com/resources/sync/index.html ) for precise timekeeping purposes? There was a discussion on this list about doing something like filling a cavern with pendulums in this connection a couple months ago. I was thinking about a large population of freerunning oscillators coupled via RF (e.g. digital pulse radio). Basically a bit like WiFi radios in line of sight, talking to nearest neighbors. Bob York at UCSB and Ron Pogorzelski, a recently retired colleague of mine at JPL, hav done a lot of work with coupled oscillator arrays. They're used as a way to do phased array antennas. googling coupled oscillator array will turn up many hits. Thank you -- very interesting. Allan had a paper where he had 8 inexpensive crystals coupled with mixers and a microcontroller. I think it's called the Clever Temperature Compensated XO or something like that. Presumably, a large population of cheap coupled oscillators could be rather accurate collectively. -- Eugen* Leitl a href=http://leitl.org;leitl/a http://leitl.org __ ICBM: 48.07100, 11.36820 http://www.ativel.com http://postbiota.org 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE ___ 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] synchronizing a large number of weakly coupled oscillators
Bob Camp wrote: Hi The tendency of clocks to self synchronize dates back at least to the days of pendulum clocks. It may date to the era of water clocks, but if so it's undocumented. It has been observed on a wide range of modern clock designs. If you look into injection locking you'll get a pretty good picture of what's going on. Oooh. Clepsydra (is that also the plural?).. one of my favorite topics.. It never occurred to me that they might couple, although almost every other mechanical clock does. What would the mechanism be? How could one set up an experiment? (hey, it's getting to be summertime, and my kids need projects that might get them wet) ___ 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] synchronizing a large number of weakly coupled oscillators
Eugen Leitl wrote: On Wed, May 12, 2010 at 06:03:11AM -0700, jimlux wrote: Allan had a paper where he had 8 inexpensive crystals coupled with mixers and a microcontroller. I think it's called the Clever Temperature Compensated XO or something like that. Presumably, a large population of cheap coupled oscillators could be rather accurate collectively. I think that there's a point of diminishing returns.. the uncertainties in the coupling start to dominate over the reduction in uncertainty from combining multiple clocks. one of those N vs sqrt(N) sort of 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] synchronizing a large number of weaklycoupled oscillators
Hi My *guess* would be that you would need to setup a situation that favored the lock. Simple outflow clocks probably aren't going to lock. Any of the escarpment designs have the potential to lock. Past that, sounds like a good reason to build up some on a flimsy shelf and see what happens. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of jimlux Sent: Wednesday, May 12, 2010 9:27 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] synchronizing a large number of weaklycoupled oscillators Bob Camp wrote: Hi The tendency of clocks to self synchronize dates back at least to the days of pendulum clocks. It may date to the era of water clocks, but if so it's undocumented. It has been observed on a wide range of modern clock designs. If you look into injection locking you'll get a pretty good picture of what's going on. Oooh. Clepsydra (is that also the plural?).. one of my favorite topics.. It never occurred to me that they might couple, although almost every other mechanical clock does. What would the mechanism be? How could one set up an experiment? (hey, it's getting to be summertime, and my kids need projects that might get them wet) ___ 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] synchronizing a large number of weaklycoupled oscillators
Hi If the oscillators all lock to each other, then multiple oscillators don't have any particular advantage. Let's assume you can isolate them so they don't lock to each other. If they are all of similar construction in a similar environment, there is a very real limit to the advantage you would obtain, no matter how many you have. It turns out that's true at one level for simple crystal clocks, and at a very different level for atomic clocks. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Eugen Leitl Sent: Wednesday, May 12, 2010 9:21 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] synchronizing a large number of weaklycoupled oscillators On Wed, May 12, 2010 at 06:03:11AM -0700, jimlux wrote: Eugen Leitl wrote: Has anyone utilized a network of locally, weakly coupled oscillator synchronization (a la http://www.projectcomputing.com/resources/sync/index.html ) for precise timekeeping purposes? There was a discussion on this list about doing something like filling a cavern with pendulums in this connection a couple months ago. I was thinking about a large population of freerunning oscillators coupled via RF (e.g. digital pulse radio). Basically a bit like WiFi radios in line of sight, talking to nearest neighbors. Bob York at UCSB and Ron Pogorzelski, a recently retired colleague of mine at JPL, hav done a lot of work with coupled oscillator arrays. They're used as a way to do phased array antennas. googling coupled oscillator array will turn up many hits. Thank you -- very interesting. Allan had a paper where he had 8 inexpensive crystals coupled with mixers and a microcontroller. I think it's called the Clever Temperature Compensated XO or something like that. Presumably, a large population of cheap coupled oscillators could be rather accurate collectively. -- Eugen* Leitl a href=http://leitl.org;leitl/a http://leitl.org __ ICBM: 48.07100, 11.36820 http://www.ativel.com http://postbiota.org 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE ___ 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] Fluke monitor
On 05/06/2010 12:29 PM, Arthur Dent wrote: But now here is the finding. The monitor board has the 7805 SMD version and I was feeding from +12Volt and after a while the SMD voltage regulator overheated and started to drop the voltage and it was the reason to receive/display garbled msg.the display is built into the same box as the gpsdo. the temp of the gpsdo was around 45 Celsius, so inside the box the temp also was elevated so no wonder why the SMD voltage reg overheated Ernie, Glad to hear you were able to find the problem. Quite often you can use a can of spray coolant to identify thermal problems like this one. The regulator is rated 0.5A but the amount of power it was asked to dissipate caused the thermal shutdown. It was working just the way it was designed. One suggestion I would make is to epoxy a small heatsink onto the chip to make sure this doesn't happen again. The 75 ohm resistor you're using will probably take care of the problem permanently but even a small heatsink cut and formed from a soda can wouldn't hurt. -Arthur My fluke.l monitor stopped working today after one overnight session. LH is connected at the same time and is reporting good data from the tbolt. I currently think that it's perhaps a clock speed issue, not a voltage issue, because I'm getting 5V out of the regulator right now and it's not working. Here's how I got here: The monitor is a recent model and has the regulator. I left it on overnight, in its original case and out in the open, hooked to a 13.5V supply. I had it on a ammeter the whole time, and it never draws more than 0.02A. The backlight is fine and the display works. It says No Message and occasionally gives garbled displays of other data. Once it said No Message / PowerSupply Fail but not again. Turning it off for an hour didn't help. I tried it at a lower voltage (8V) and it works some, alternating between No Message and some data or otehr every few minutes, but the data doesn't appear to be accurate (claiming 2D/3D mode when it's not, including question marks in numeric fields, etc). With 12.2V-13.5V in, I get 4.99-5.01V from the square via on the left of the board to the 3 round vias next to it, yet I still get No message or garbled data. Leigh/WA5ZNU ___ 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] Fluke monitor
Hi Leigh: Is the wiring to the monitor exposed such that you can touch it? I think mine died because of static zap to the exposed wiring. http://www.prc68.com/I/ThunderBolt.shtml#iCruze Have Fun, Brooke Clarke http://www.PRC68.com Leigh L. Klotz, Jr WA5ZNU wrote: On 05/06/2010 12:29 PM, Arthur Dent wrote: But now here is the finding. The monitor board has the 7805 SMD version and I was feeding from +12Volt and after a while the SMD voltage regulator overheated and started to drop the voltage and it was the reason to receive/display garbled msg.the display is built into the same box as the gpsdo. the temp of the gpsdo was around 45 Celsius, so inside the box the temp also was elevated so no wonder why the SMD voltage reg overheated Ernie, Glad to hear you were able to find the problem. Quite often you can use a can of spray coolant to identify thermal problems like this one. The regulator is rated 0.5A but the amount of power it was asked to dissipate caused the thermal shutdown. It was working just the way it was designed. One suggestion I would make is to epoxy a small heatsink onto the chip to make sure this doesn't happen again. The 75 ohm resistor you're using will probably take care of the problem permanently but even a small heatsink cut and formed from a soda can wouldn't hurt. -Arthur My fluke.l monitor stopped working today after one overnight session. LH is connected at the same time and is reporting good data from the tbolt. I currently think that it's perhaps a clock speed issue, not a voltage issue, because I'm getting 5V out of the regulator right now and it's not working. Here's how I got here: The monitor is a recent model and has the regulator. I left it on overnight, in its original case and out in the open, hooked to a 13.5V supply. I had it on a ammeter the whole time, and it never draws more than 0.02A. The backlight is fine and the display works. It says No Message and occasionally gives garbled displays of other data. Once it said No Message / PowerSupply Fail but not again. Turning it off for an hour didn't help. I tried it at a lower voltage (8V) and it works some, alternating between No Message and some data or otehr every few minutes, but the data doesn't appear to be accurate (claiming 2D/3D mode when it's not, including question marks in numeric fields, etc). With 12.2V-13.5V in, I get 4.99-5.01V from the square via on the left of the board to the 3 round vias next to it, yet I still get No message or garbled data. Leigh/WA5ZNU ___ 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] Fluke monitor
My fluke.l monitor stopped working today ... Mine stopped yesterday The monitor is a recent model and has the regulator. So does mine and I run the board from a 9V regulator. The display is built into the same box as the gpsdo I left it on overnight, Mine has been on continuously for over a month The backlight is fine and the display works. and occasionally gives garbled displays of other data. alternating between ... some data or other every few minutes, but the data doesn't appear to be accurate...including question marks in numeric fields, Same thing here Other errors that I get : 2 lines of date time Only one line of date time on the display It has frozen displaying only one line of date time for several minutes Sometimes displays TSIP LED Monit Ocassionally only the back-light is on, nothing displayed This lasts for a couple minutes then resumes normal display. There seems to be a pattern developing. Is this an inherent problem with the processor board or with the software? All together, mine has been in operation about 3 months which would seem to rule out a software problem. The occasional display of TSIP LED Monit would indicate that the processor is being reset as this is normally seen at power-up. Maury W5UGQ ___ 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] Fluke monitor
In a message dated 12/05/2010 17:45:16 GMT Daylight Time, le...@wa5znu.org writes: The monitor is a recent model and has the regulator. I left it on overnight, in its original case and out in the open, hooked to a 13.5V supply. I had it on a ammeter the whole time, and it never draws more than 0.02A. The backlight is fine and the display works. -- Something doesn't seem right with that current consumption. Mine's not in use at the moment, as my test area is still stripped down, but when it was I measured a consistent 47mA once the regulator had a high enough supply to ensure it was regulating, in my case I was using 12 volts but the current is determined by the regulator output voltage so shouldn't vary much anyway. The display is what was fitted originally fitted to the iCruze module but the processor board has been changed so that Didier's Tbolt Monitor code can be used. The processor module circuit is pretty basic so I wouldn't have thought there was too much room for a design error. I'd be inclined to start by separating the processor board from the display and then reconnect using a temporary link of flexible wiring so as to be able to check if the processor circuitry is actually drawing current, then I'd probably continue by looking for quality issues, bad joints, solder bridges, etc. If that turned up nothing obvious then a more in depth examination of what the processor is doing would be my next step, in particular it would be interesting to know how it's handling the RS232 interfacing just in case it's a comms issue. Given that Didier's code is freely available, and the processor board schematic is easily traced, it shouldn't be too difficult as a last resort just to build a replacement. regards Nigel GMPZR ___ 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] Fluke monitor
Must be the Y2.01K bug... Sorry about the problems being reported recently. While I have no association with Bob of Fluke.l, he is using my design and he was kind enough to send me one demo model, which I have yet to turn on. In general, if the processor is not fried, there is very little that can go wrong: 1) check that the serial data getting to the processor is clean. Noise on these lines in unforgiving since the protocol has no error detection or correction. In my design, I use a single bipolar transistor to convert the RS-232 to TTL. Not the best way to do it if noise is a concern. It works fine for me, but YMMV 2) check the interface to the LCD. There are 7 wires in addition to ground and +5V. An intermittent connection with cause trouble. 3) check the supply voltage. Most regulators should work fine with 7V input, more voltage only makes more heat. With an LCD display, the current consumption should be low (20 to 50mA) and relatively constant, mostly a function of the backlight. With a VFD display, the consumption is quite a bit higher (several hundred mA) and fluctuates depending on how many segments (pixels) are turned on. Didier msproul mspr...@suddenlink.net wrote: My fluke.l monitor stopped working today ... Mine stopped yesterday The monitor is a recent model and has the regulator. So does mine and I run the board from a 9V regulator. The display is built into the same box as the gpsdo I left it on overnight, Mine has been on continuously for over a month The backlight is fine and the display works. and occasionally gives garbled displays of other data. alternating between ... some data or other every few minutes, but the data doesn't appear to be accurate...including question marks in numeric fields, Same thing here Other errors that I get : 2 lines of date time Only one line of date time on the display It has frozen displaying only one line of date time for several minutes Sometimes displays TSIP LED Monit Ocassionally only the back-light is on, nothing displayed This lasts for a couple minutes then resumes normal display. There seems to be a pattern developing. Is this an inherent problem with the processor board or with the software? All together, mine has been in operation about 3 months which would seem to rule out a software problem. The occasional display of TSIP LED Monit would indicate that the processor is being reset as this is normally seen at power-up. Maury W5UGQ ___ 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] synchronizing a large number ofweaklycoupled oscillators
Hi If the oscillators all lock to each other, then multiple oscillators don't have any particular advantage. Let's assume you can isolate them so they don't lock to each other. If they are all of similar construction in a similar environment, there is a very real limit to the advantage you would obtain, no matter how many you have. It turns out that's true at one level for simple crystal clocks, and at a very different level for atomic clocks. Bob Multiple oscillators locking implies that some energy is given off by some clocks and received by others. The modern way is simply to compare the clocks in isolation and manage the ensemble as a paper clock, in software; no injection locking in this case. You can create any mean you want, weighted or not. UTC is a good example of this. /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] Time nuttiness at Dayton!
Who is headed to Dayton?? Any vendors with junk? cu there! 73 de Norm n3ykf ___ 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] synchronizing a large number of weakly coupled oscillators
Presumably, a large population of cheap coupled oscillators could be rather accurate collectively. Why? There are 2 main sources of error in inexpensive crystal oscillators. The first is the initial manufacturing error. I'd expect crystals made from the same batch to have similar errors. If you want a large population, you are going to get most/many of them from similar batches. The other is temperature. I'd expect that oscillators of a specific design to have similar temperature dependencies. Some vendors even include a graph in their app-notes. It might be interesting to collect oscillators from different vendors and batches and see what sort of spread you end up with. -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Time nuttiness at Dayton!
Stop by the TAPR booth! I'll be there most of the time (when I'm not out snooping around in the flea market). John normn3...@stny.rr.com said the following on 05/12/2010 06:08 PM: Who is headed to Dayton?? Any vendors with junk? cu there! 73 de Norm n3ykf ___ 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] synchronizing a large number of weakly coupled oscillators
Well I guess no because accuracy is the deviation from a known standard (I think) Stability repeatability might be better but you need to consider what the variables might be. Variations in thickness (basically frequency), cut angle (temp coeficient and maybe others), crystal purity (aging, ESR ?). If you average many randomly selected samples you might reduce the level of variablilty of these aspects but would that make them more accurate? I doubt that maybe more capable of staying within a given accuracy once adjusted. I still think the cost effective way is get one good one, the best you can afford, characterise it and the make adjustments either calculated or by disciplining. Even an ordinary crystal can be made to perform quite well by adjusting it to track it to something better. Many LF BC stations in Europe are much better than a cheapy (computer grade) crystal and Droitwich and Allouis are locked to a Rb standard and regularly measure against the national standards. A few part in 10^11 costs a couple of hundred dollars.This is 5 orders better than a cheapy crystal. My back of envelope calculation suggest you might need about 100,000 oscillators to achieve this level (ok tell me I'm wrong with the calculation and, as the exam script says, show you working .the red wine was very nice I can take it !! :-)) ) Alan G3NYK - Original Message - From: Hal Murray hmur...@megapathdsl.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Wednesday, May 12, 2010 11:31 PM Subject: Re: [time-nuts] synchronizing a large number of weakly coupled oscillators Presumably, a large population of cheap coupled oscillators could be rather accurate collectively. Why? There are 2 main sources of error in inexpensive crystal oscillators. The first is the initial manufacturing error. I'd expect crystals made from the same batch to have similar errors. If you want a large population, you are going to get most/many of them from similar batches. The other is temperature. I'd expect that oscillators of a specific design to have similar temperature dependencies. Some vendors even include a graph in their app-notes. It might be interesting to collect oscillators from different vendors and batches and see what sort of spread you end up with. -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] time-nuts Digest, Vol 70, Issue 31
On 5/12/2010 10:41 AM, Jim Lux wrote: It never occurred to me that they might couple, although almost every other mechanical clock does. What would the mechanism be? Perhaps if all of them run off the same reservoir ___ 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] time-nuts Digest, Vol 70, Issue 31
Is it possible that mechanical (pendulum) clocks could couple not due to energy transfer between the clocks but external mechanical events such as seismic events of a very low level ?? or even gravitational or lunar gravitational effects.?? Maybe the same for water clocks ?? Alan G3NYK - Original Message - From: Christopher Hoover c...@murgatroid.com To: time-nuts@febo.com Sent: Thursday, May 13, 2010 1:00 AM Subject: Re: [time-nuts] time-nuts Digest, Vol 70, Issue 31 On 5/12/2010 10:41 AM, Jim Lux wrote: It never occurred to me that they might couple, although almost every other mechanical clock does. What would the mechanism be? Perhaps if all of them run off the same reservoir ___ 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] time-nuts Digest, Vol 70, Issue 31
That would not explain the lessing of the effect as the clocks are moved father from each other or arranged as sides of a triangle. Maybe gravity between the pendulums or more likely vibrations. http://www.scholarpedia.org/article/Synchronization http://www.siam.org/pdf/news/481.pdf http://www.bhi.co.uk/hj/Coupled%20Pendulums%20Quadrature%20and%20Clocks%20by%20John%20Haine.pdf http://www.ralph-abraham.org/articles/MS%2344.Resonance/ms44.pdf Stanley - Original Message From: Alan Melia alan.me...@btinternet.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Wed, May 12, 2010 7:12:55 PM Subject: Re: [time-nuts] time-nuts Digest, Vol 70, Issue 31 Is it possible that mechanical (pendulum) clocks could couple not due to energy transfer between the clocks but external mechanical events such as seismic events of a very low level ?? or even gravitational or lunar gravitational effects.?? Maybe the same for water clocks ?? Alan G3NYK - Original Message - From: Christopher Hoover c...@murgatroid.com To: time-nuts@febo.com Sent: Thursday, May 13, 2010 1:00 AM Subject: Re: [time-nuts] time-nuts Digest, Vol 70, Issue 31 On 5/12/2010 10:41 AM, Jim Lux wrote: It never occurred to me that they might couple, although almost every other mechanical clock does. What would the mechanism be? Perhaps if all of them run off the same reservoir ___ 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.
