Re: [time-nuts] Maser on a chip
I have a Science subscription so can read the complete paper and supplementary material. Their current device has about two orders of magnitude greater linewidth (34 kHz) than the ~400 Hz linewidth predicted from maser theory. The coherence time is ~9.4 us. They suggest this is due to charge flunctuations, and show time domain examples of the I/Q downconverted signal with discontinuities where the device drops out of masing. This is a moderately complex experimental setup, with very low signal levels requiring a superconducting Josephson parametric amplifier for some measurements at a reasonably S/N. The device maser cavity is superconducting. I agree that this is an initial proof of concept demonstrating masing with quantum dots. -- Bill Byrom N5BB Tektronix RF Application Engineer On Tue, Jan 20, 2015, at 01:51 AM, Attila Kinali wrote: On Sun, 18 Jan 2015 22:59:57 + Mark Sims hol...@hotmail.com wrote: http://www.princeton.edu/main/news/archive/S42/13/37M75/index.xml Not much detail there... but there is an article in Science. It looks like the supplemantary material[1] of the paper isnt behind a pay wall. Attila Kinali [1] http://www.sciencemag.org/content/347/6219/285/suppl/DC1 -- It is upon moral qualities that a society is ultimately founded. All the prosperity and technological sophistication in the world is of no use without that foundation. -- Miss Matheson, The Diamond Age, Neil Stephenson ___ 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] D term (was no subject)
On 1/25/15 1:30 PM, WarrenS via time-nuts wrote: I second Poul-Henning Kamp's comments concerning D-terms, (mostly) as done in the TBolt and likely other GPSDOs. Bear in mind that a PID loop is basically a fairly simple control loop that is easily susceptible to linear analysis. They're simple to implement with analog controls, they're simple to analyze, and for a whole lot of applications, they'll work just fine. And there's decades, if not centuries, of experience with P, PI and PID controllers in a practical sense. A lot of people know how to *tune* the parameters based on observed system dynamics. But for a lot of systems:ones where there are significant nonlinearities and/or time delays and/or saturation/limiting effects a PID loop might not be a good choice. (for instance, if you're doing a closed loop position control with a stepper motor as the actuator, with a small motor and a big heavy load, with low friction...) For myself, I am seduced by the idea of a control system that builds and adjusts a model of the system being controlled, and then derives the needed control inputs from inverting that model (whether arithmetically, or by some clever algorithmic means). For instance, a PID controller doing temperature control doesn't have a *good* way of incorporating side information like the outside temperature. There's all kinds of schemes for doing this (double loops, extra terms, etc.) ___ 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] Help me make some sense of adev measurements of SR620'sown clock
On 25 Jan 2015 23:02, Tom Van Baak t...@leapsecond.com wrote: You're getting 1e-12 at 1 second. Sounds fine to me. Obviously you have the experience to know that 1e-12 at 1 second is fine. But if it's possible, I would like to understand the relationship between the counters specification and the adev (or one of the modifications of it) one would expect to see. Obviously it is nice to know that the counter is working ok, but I would like to understand how one can ascertain that from the data I recorded, based on the SR620's specifications. Also, when you plot phase with TimeLab you'll notice a jump around T+23600 seconds. This is likely you breathing near the instrument, or touching a cable, or closing a door. That's interesting. It is about 4:30 am local time here, so when I was asleep. I would have expected data then to be better than during the day when I move around. The biggest disturbance occurred at a time I would have least expected it. Do most people save time information as I have done there, or phase information? Always save phase. Not sure what you mean by time. The counter can measure the time between the start and stop inputs, which is what I done. The numbers are around 17.5 ns due to the cable length. But instead of saving those time values, I could have configured the counter to save the phase in the range -180 to +180 degrees. Your adev1 programe expected time in seconds rather than phase in degrees, which is why I saved time rather than phase. But I will use adev5 as you suggested. I used adev1 primarily since you had a web page on it. I am not talking about elapsed time, time of the day etc. That's something quite different. Even better is to save both phase and elapsed time or real time; the latter can be used as a check that your sample rates are what you expect. I did save elapsed time as you can see. I was in fact a bit surprised that the data points are spaced very slightly *less* than a second apart. I would have expected the data to take 1 second to collect, then some time processing time, especially since I introduced a delay of about 200 us to stop the GPIB reads randomly failing. That's a bit of a mystery. Personally, I prefix every ascii line received with a MJD timestamp. That way all my log files, everything from counters to temperature sensors to GPS NMEA lines can all be correlated against themselves and with other people. I had never heard of the MJD, but I will do what you suggest. Data collection started at: 23:2:55 GMT on 24/01/2015 (day/month/year format) Always use leading zeros for hours, minutes, and seconds. That was not intensional. I would have intended to put the leading zero. The preferred way to write this is simply 2015-01-24 23:02:55 (see ISO 8601). OK, I'll do that, despite it seems quite unnatural to us brits! John's software looks impressive. In fact is TimePod hardware too, but far out of my budget. I will have to make do with the SR620. I just wish I didn't have to load the data into a Windows program. Maybe at some point I will try to get gnuplot to do similar. /tvb Thank you Tom. Also to Bob. I will do as Bob suggested and repeat using an external 10 MHz source, rather than use the counters own timebase. 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] Unique TBolt GPS characteristics
Another unique thing about the TBolt engine is how fast it can calculate a Freq change in its 10MHz osc. Over short times periods, it can be 100 times better than a standard 1PPS GPS engine. It would be interesting to compare it to a high end dual freq GPS. With the Tbolt in manual hold over mode, and using Lady Heather for the readout, It takes less than 10 seconds, to measure the freq offset to well under 1e-11. Typically about 1e-11 freq error in 3 seconds When setup to use an external freq input, it makes a fast 11 plus digit, 10 MHz freq counter. The PPT output (osc Freq offset) of the Tbolt, responds to any freq changes in the next 1 sec output. How it does this is a mystery to me, because it is not using phase error. The limit is the noise which is very low. In a well set up Tbolt, the 1 second PPT freq noise is about 10ppt RMS (50e-12 PP). 5e-12 with 5sec filter, 3.5e-12 with 10 sec filter and 2.5e-12 with a 50 second filter. Attached is an old plot showing the noise floor difference between the TBolts phase and Freq outputs. The Uncertainty of a non-sawtooth corrected 1 sec GPS can be around 10 ns plus, with sawtooth correction that can go down to near 1ns uncertainty The GPS signal its self has up to a 10 ns uncertainly, so using the 1PPS signal out of a common GPS engine you get at best a 1e-8 to 1e-9 freq uncertainty using two readings 1 second apart. ws * This operation is very typical of all of the cell site GPSDO's. The only part that is unique to the TBolt is the ability to fiddle the loop characteristics a bit. bob And the fact that the GPS's CPU clock is derived from the 10MHz and therefore aligned to the PPS so there is no hanging bridge and sawtooth correction is not required. I am not aware of any other GPSDO implementing that scheme, which is very elegant in its simplicity. Didier KO4BB ** It is indeed an elegant solution. Based on looking at 1 pps outputs on a group of them over a year or more, It's actual impact on the control loop function is pretty minor compared to a properly executed sawtooth correction process. It would have a significant advantage if compared to a GPSDO that does not use sawtooth correction. Bob ___ 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] LTE Lite time error
Odd indeed. My LTE-lite is one second late, appears to have already added the pending leap second. I can compare with four other GPS timeing receivers using time pulse on DCD line. The NMEA data reports in error. I am awaiting reply from JL. This is not good for an eBay sniper Bill, NL7F On Sun, 25 Jan 2015 12:12:55 -0800, Tom Van Baak wrote: Hi Paul, Odd, my LTE-Lite appears spot on. Let's take this off-list and see what's going on. If anyone else has been logging SkyTraq NMEA or binary from the LTE-Lite let us know. Bill Beam NL7F ___ 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] D term (was no subject)
Maybe we are getting a little off-topic here, but a very long time ago I was dealing with industrial ovens used to braze ceramics used to make microwave tubes. It was very difficult to maintain the precise temperature ramp up and down, particularly as the oven was not always loaded the same way. In order to automatically compensate for different oven loading (and ambient conditions), the controller injected a very low level random noise over the temperature setting and by analyzing how that noise was filtered by going through the oven, was able to determine the response of the oven itself and from that optimize the PID terms in real time as a function of the load. This was in the early 80's. It was pretty hot stuff then, even for an oven :) Didier KO4BB On Sun, Jan 25, 2015 at 8:12 PM, Jim Lux jim...@earthlink.net wrote: On 1/25/15 1:30 PM, WarrenS via time-nuts wrote: I second Poul-Henning Kamp's comments concerning D-terms, (mostly) as done in the TBolt and likely other GPSDOs. Bear in mind that a PID loop is basically a fairly simple control loop that is easily susceptible to linear analysis. They're simple to implement with analog controls, they're simple to analyze, and for a whole lot of applications, they'll work just fine. And there's decades, if not centuries, of experience with P, PI and PID controllers in a practical sense. A lot of people know how to *tune* the parameters based on observed system dynamics. But for a lot of systems:ones where there are significant nonlinearities and/or time delays and/or saturation/limiting effects a PID loop might not be a good choice. (for instance, if you're doing a closed loop position control with a stepper motor as the actuator, with a small motor and a big heavy load, with low friction...) For myself, I am seduced by the idea of a control system that builds and adjusts a model of the system being controlled, and then derives the needed control inputs from inverting that model (whether arithmetically, or by some clever algorithmic means). For instance, a PID controller doing temperature control doesn't have a *good* way of incorporating side information like the outside temperature. There's all kinds of schemes for doing this (double loops, extra terms, etc.) ___ 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] Tek FCA3100/Pendulum CNT91 vs Keysight/Agilen 53230A
Hi Time Nuts This is my first posting on Time-Nuts though I've been reading others postings for quite a while. I am thinking of upgrading my very basic counter but only have limited lab space which rules out the SRS 620 on the basis of physical size. Tektronix are offering an ex demo FCA3100 (which I think is a rebadged Pendulum CNT91) and the other choice seems to be to wait for the Keysight store to get some more 53230As in (I missed out on the last lot about six months ago). I am finding it hard to compare the FCA3100 to the 53230 in terms of practical differences (as apposed to the data sheet numbers). The key difference seems to be the single shot resolution of 20 psecs for the 53230A compared to 50 psecs for the FCA3100. I've seen three sets of results for the 53230A which actually measure around 8 to 11 psecs (using the delay of a length of coax method). But I've not seen any practical results for the FCA3100. If it is up at the 50 psec mark and the 53230A is really nearer 10 psecs then the difference between the two is even more marked than the data sheet numbers. Have any owners of the FCA3100/CNT 91 done such measurements? The FCA3100's main advantage over the 53230A is that it is cheaper but it also seems to have higher voltage resolution (1mV vs 2.5mV) and less noise (200 uV vs 350uV typical) and it has a pulse generator that I might find quite useful. Is there anything else I should consider? Any practical info/advice would be much appreciated. I'm hoping to use it for general GPSDO development and other experiments. James ___ 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] D term (was no subject)
On 1/26/15 5:55 AM, Poul-Henning Kamp wrote: In message 54c5a270.7090...@earthlink.net, Jim Lux writes: And there's decades, if not centuries, of experience with P, PI and PID controllers in a practical sense. Not quite a century I belive: Only the advent of electronics formalized the theory and developed the practice. Almost all mechanical governors er pure P. Maxwell strikes again http://upload.wikimedia.org/wikipedia/commons/b/b1/On_Governors.pdf definitely more than P controllers.. cups with liquid (Siemens governor), nonlinear mechanisms, etc. ___ 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] LTE Lite time error
We have confirmed this issue with the Skytraq firmware on the LTE-Lite and are working with Skytraq to obtain a firmware update. I will post again when a firmware update is available. Keith Keith On Sun, Jan 25, 2015 at 5:47 PM, Bill Beam wb...@gci.net wrote: Odd indeed. My LTE-lite is one second late, appears to have already added the pending leap second. I can compare with four other GPS timeing receivers using time pulse on DCD line. The NMEA data reports in error. I am awaiting reply from JL. This is not good for an eBay sniper Bill, NL7F On Sun, 25 Jan 2015 12:12:55 -0800, Tom Van Baak wrote: Hi Paul, Odd, my LTE-Lite appears spot on. Let's take this off-list and see what's going on. If anyone else has been logging SkyTraq NMEA or binary from the LTE-Lite let us know. Bill Beam NL7F ___ 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] question Alan deviation measured with Timelab and counters
The performance of the 2 systems should be comparable provided the similar equivalent noise bandwidths are used.Every 10Mhz edge needs to be timestamped with ps resolution and the resulting phase samples low pass filtered and decimated to achieve this.The 10MSPS picosecond or better resolution time stamping with femtosecond integral linearity will be a bit of a challenge to achieve. Bruce On Tuesday, 27 January 2015 3:26 PM, Stéphane Rey steph@wanadoo.fr wrote: I do understand. Has anyone already compared the performances of squaring the 10 MHz vs squaring the IF ? Stephane -Message d'origine- De : time-nuts [mailto:time-nuts-boun...@febo.com] De la part de Bob Camp Envoyé : dimanche 25 janvier 2015 19:01 À : Discussion of precise time and frequency measurement Objet : Re: [time-nuts] question Alan deviation measured with Timelab and counters Hi The approach in the original NIST paper below was sort of a “best guess” about how to do the limiting and filtering. When the paper was presented, a number of us questioned how that part of the circuit was arrived at. The conversation more or less ended up with “that’s something we can investigate further”. The Collins paper (and Bruce’s work based on it) is a much better way to look at the 10 Hz squaring process. At 10 MHz, that stuff is not needed. Bob On Jan 25, 2015, at 10:44 AM, Stéphane Rey steph@wanadoo.fr wrote: Hi everyone. Many thanks for your very useful comments. I had already seen most of the documents you were pointing but not on the collins and Bruce discussion around the multistage filter. However I've already seen this approach in the document from Allan (http://tf.nist.gov/timefreq/general/pdf/84.pdf) At first I had in mind to square the 10 MHz but this is the aim of the evaluation board to evaluate various architectures. So I will implement several squarers including the Collins Approach both at 10 MHz and 100 Hz and all the blocks will have input and output connectors so that I will be able to test several layouts. I will show you the final design. Cheers Stephane -Message d'origine- De : time-nuts [mailto:time-nuts-boun...@febo.com] De la part de Charles Steinmetz Envoyé : dimanche 25 janvier 2015 08:08 À : Discussion of precise time and frequency measurement Objet : Re: [time-nuts] question Alan deviation measured with Timelab and counters Stephane wrote: I'm now trying to evaluate various architectures of 2-channels squarers and a DMDT. For that I'm designing a PCB with 4 squarers : simple 74ac04 gate biased at VCC/2, a LT1016 comparator, the transistor based differential amplifier from Winzel and the one from Charles. Note that squaring a 10MHz sine wave and squaring a 10 or 100Hz mixer output are two very different tasks. If you start at baseband, a Collins-style multi-stage limiting amp is a great benefit. That is generally not necessary if you start at 10MHz (or if you do use a Collins-style limiter it needs far fewer stages). All of the squarers you mention work well at 10MHz, but not as well at baseband. The LT1719 is easier to apply and faster than the LT1016. You may want to use that instead of the 1016. The LT1719 and LT1715 datasheets show the simplest possible implementation (see below). The MPSH81 devices in my version are available in surface-mount (MMBTH81) if that is more convenient. Other fast transistors will also work (BFT92, BFT93, BFG31). Best regards, Charles --- L'absence de virus dans ce courrier électronique a été vérifiée par le logiciel antivirus Avast. http://www.avast.com ___ 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. --- L'absence de virus dans ce courrier électronique a été vérifiée par le logiciel antivirus Avast. http://www.avast.com ___ 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] question Alan deviation measured with Timelab and counters
I do understand. Has anyone already compared the performances of squaring the 10 MHz vs squaring the IF ? Stephane -Message d'origine- De : time-nuts [mailto:time-nuts-boun...@febo.com] De la part de Bob Camp Envoyé : dimanche 25 janvier 2015 19:01 À : Discussion of precise time and frequency measurement Objet : Re: [time-nuts] question Alan deviation measured with Timelab and counters Hi The approach in the original NIST paper below was sort of a “best guess” about how to do the limiting and filtering. When the paper was presented, a number of us questioned how that part of the circuit was arrived at. The conversation more or less ended up with “that’s something we can investigate further”. The Collins paper (and Bruce’s work based on it) is a much better way to look at the 10 Hz squaring process. At 10 MHz, that stuff is not needed. Bob On Jan 25, 2015, at 10:44 AM, Stéphane Rey steph@wanadoo.fr wrote: Hi everyone. Many thanks for your very useful comments. I had already seen most of the documents you were pointing but not on the collins and Bruce discussion around the multistage filter. However I've already seen this approach in the document from Allan (http://tf.nist.gov/timefreq/general/pdf/84.pdf) At first I had in mind to square the 10 MHz but this is the aim of the evaluation board to evaluate various architectures. So I will implement several squarers including the Collins Approach both at 10 MHz and 100 Hz and all the blocks will have input and output connectors so that I will be able to test several layouts. I will show you the final design. Cheers Stephane -Message d'origine- De : time-nuts [mailto:time-nuts-boun...@febo.com] De la part de Charles Steinmetz Envoyé : dimanche 25 janvier 2015 08:08 À : Discussion of precise time and frequency measurement Objet : Re: [time-nuts] question Alan deviation measured with Timelab and counters Stephane wrote: I'm now trying to evaluate various architectures of 2-channels squarers and a DMDT. For that I'm designing a PCB with 4 squarers : simple 74ac04 gate biased at VCC/2, a LT1016 comparator, the transistor based differential amplifier from Winzel and the one from Charles. Note that squaring a 10MHz sine wave and squaring a 10 or 100Hz mixer output are two very different tasks. If you start at baseband, a Collins-style multi-stage limiting amp is a great benefit. That is generally not necessary if you start at 10MHz (or if you do use a Collins-style limiter it needs far fewer stages). All of the squarers you mention work well at 10MHz, but not as well at baseband. The LT1719 is easier to apply and faster than the LT1016. You may want to use that instead of the 1016. The LT1719 and LT1715 datasheets show the simplest possible implementation (see below). The MPSH81 devices in my version are available in surface-mount (MMBTH81) if that is more convenient. Other fast transistors will also work (BFT92, BFT93, BFG31). Best regards, Charles --- L'absence de virus dans ce courrier électronique a été vérifiée par le logiciel antivirus Avast. http://www.avast.com ___ 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. --- L'absence de virus dans ce courrier électronique a été vérifiée par le logiciel antivirus Avast. http://www.avast.com ___ 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] LTE Lite time error
Skytraq has also confirmed the issue and is working on a firmware update. Updating the Skytraq firmware on the LTE-Lite Eval Board requires the unit be returned to Jackson Labs for reprogramming. We will update the Skytraq firmware on units at no charge if units are returned to us. Please contact us off list to make arrangements for returns. Also, the ROM firmware in the Skytraq does not exhibit this issue, so selecting the ROM boot with a jumper between pins 1 and 2 of J3 is a work-around. When making the J3 connection, be sure to remove power to the board to avoid corrupting the flash. The LTE-Lite will operate in a mobile mode without sawtooth correction when the Skytraq is booted from ROM. Thanks, Keith Keith On Mon, Jan 26, 2015 at 10:43 AM, Keith Loiselle keith.loise...@gmail.com wrote: We have confirmed this issue with the Skytraq firmware on the LTE-Lite and are working with Skytraq to obtain a firmware update. I will post again when a firmware update is available. Keith Keith On Sun, Jan 25, 2015 at 5:47 PM, Bill Beam wb...@gci.net wrote: Odd indeed. My LTE-lite is one second late, appears to have already added the pending leap second. I can compare with four other GPS timeing receivers using time pulse on DCD line. The NMEA data reports in error. I am awaiting reply from JL. This is not good for an eBay sniper Bill, NL7F On Sun, 25 Jan 2015 12:12:55 -0800, Tom Van Baak wrote: Hi Paul, Odd, my LTE-Lite appears spot on. Let's take this off-list and see what's going on. If anyone else has been logging SkyTraq NMEA or binary from the LTE-Lite let us know. Bill Beam NL7F ___ 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] LTE Lite time error
Be careful with 'eyeball data'. GPS receiver does not generate NMEA time data and the leading edge of PPS at the same time. Programs like Tac32 (totally accurate clock) and Lady Heather increment the time display at the leading edge of PPS with a value 1 second greater than the previous NMEA data time. I am able to run multiple GPS receivers into multiple computers running Tac32. The LTE-lite displays one second earlier than all the others. Prior to the announcement of Leap Second Pending in the GPS data stream the LTE-lite agreed with all other units. Now it does not. On Mon, 26 Jan 2015 22:59:36 +0100, Mike Cook wrote: Yes there is certainly an error here: With my timing module I was just eyeballing the output on a windows platform , comparing GUI data. I have just linked the module up to a BeagleBone Black syncGd with NTP and this is the NMEA msg log: root@bb3:/home/mike/serial-ports# while read GGA; do echo `date` $GGA; done /dev/ttyO4 Mon Jan 26 21:51:07 UTC 2015 $GPGGA,215106.000,4847.3526,N,00216.3005,E,1,04,2.8,192.8,M,47.0,M,,*5C Mon Jan 26 21:51:07 UTC 2015 $GPGLL,4847.3526,N,00216.3005,E,215106.000,A,A*56 Mon Jan 26 21:51:07 UTC 2015 $GPGSA,A,3,25,12,06,31,3.0,2.8,1.0*3A Mon Jan 26 21:51:07 UTC 2015 $GPRMC,215106.000,A,4847.3526,N,00216.3005,E,000.0,173.5,260115,,,A*60 Mon Jan 26 21:51:07 UTC 2015 $GPVTG,173.5,T,,M,000.0,N,000.0,K,A*0D Mon Jan 26 21:51:07 UTC 2015 $GPZDA,215106.000,26,01,2015,00,00*54 Mon Jan 26 21:51:07 UTC 2015 $PSTI,00,2,0,4.6,,*30 snip The time data is all a second late so they appear to have a serious issue. Le 26 janv. 2015 + 02:47, Bill Beam wb...@gci.net a +ªcrit : snip Odd indeed. My LTE-lite is one second late, appears to have already added the pending leap second. I can compare with four other GPS timeing receivers using time pulse on DCD line. The NMEA data reports in error. snip Bill Beam NL7F ___ 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] D term (was no subject)
In message 5E5E892CF8A2440FBF18FFAD000B65FD@NewComputer, Lee Mushel writes: I'm fairly sure that Jim is right. I never had to worry about PID machine control before the late sixties and by the mid-seventies the concepts were firmly in place and in use. The basic math of PID has been around for about 100 years. The invention of the servo (and synchro/resolver) is what makes its day... Almost all mechanical governors er pure P. Maxwell strikes again http://upload.wikimedia.org/wikipedia/commons/b/b1/On_Governors.pdf definitely more than P controllers.. I said Almost all... :-) -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] LTE Lite time error
Yes there is certainly an error here: With my timing module I was just eyeballing the output on a windows platform , comparing GUI data. I have just linked the module up to a BeagleBone Black sync’d with NTP and this is the NMEA msg log: root@bb3:/home/mike/serial-ports# while read GGA; do echo `date` $GGA; done /dev/ttyO4 Mon Jan 26 21:51:07 UTC 2015 $GPGGA,215106.000,4847.3526,N,00216.3005,E,1,04,2.8,192.8,M,47.0,M,,*5C Mon Jan 26 21:51:07 UTC 2015 $GPGLL,4847.3526,N,00216.3005,E,215106.000,A,A*56 Mon Jan 26 21:51:07 UTC 2015 $GPGSA,A,3,25,12,06,31,3.0,2.8,1.0*3A Mon Jan 26 21:51:07 UTC 2015 $GPRMC,215106.000,A,4847.3526,N,00216.3005,E,000.0,173.5,260115,,,A*60 Mon Jan 26 21:51:07 UTC 2015 $GPVTG,173.5,T,,M,000.0,N,000.0,K,A*0D Mon Jan 26 21:51:07 UTC 2015 $GPZDA,215106.000,26,01,2015,00,00*54 Mon Jan 26 21:51:07 UTC 2015 $PSTI,00,2,0,4.6,,*30 Mon Jan 26 21:51:08 UTC 2015 $GPGGA,215107.000,4847.3526,N,00216.3005,E,1,04,2.8,192.8,M,47.0,M,,*5D Mon Jan 26 21:51:08 UTC 2015 $GPGLL,4847.3526,N,00216.3005,E,215107.000,A,A*57 Mon Jan 26 21:51:08 UTC 2015 $GPGSA,A,3,25,12,06,31,3.0,2.8,1.0*3A Mon Jan 26 21:51:08 UTC 2015 $GPGSV,3,1,10,25,73,294,42,12,59,063,44,14,45,264,20,29,41,196,25*7B Mon Jan 26 21:51:08 UTC 2015 $GPGSV,3,2,10,24,34,136,13,02,28,091,21,31,22,306,34,06,19,047,37*74 Mon Jan 26 21:51:08 UTC 2015 $GPGSV,3,3,10,32,03,310,,03,01,347,*7A Mon Jan 26 21:51:08 UTC 2015 $GPRMC,215107.000,A,4847.3526,N,00216.3005,E,000.0,173.5,260115,,,A*61 Mon Jan 26 21:51:08 UTC 2015 $GPVTG,173.5,T,,M,000.0,N,000.0,K,A*0D Mon Jan 26 21:51:08 UTC 2015 $GPZDA,215107.000,26,01,2015,00,00*55 Mon Jan 26 21:51:08 UTC 2015 $PSTI,00,2,0,-3.9,,*15 The time data is all a second late so they appear to have a serious issue. I module I have is the NS-T from NavSpark, so I will get on to them to see if they have a fix. Updates later. Ceux qui sont prêts à abandonner une liberté essentielle pour obtenir une petite et provisoire sécurité, ne méritent ni liberté ni sécurité. Benjimin Franklin Le 26 janv. 2015 à 02:47, Bill Beam wb...@gci.net a écrit : Odd indeed. My LTE-lite is one second late, appears to have already added the pending leap second. I can compare with four other GPS timeing receivers using time pulse on DCD line. The NMEA data reports in error. I am awaiting reply from JL. This is not good for an eBay sniper Bill, NL7F On Sun, 25 Jan 2015 12:12:55 -0800, Tom Van Baak wrote: Hi Paul, Odd, my LTE-Lite appears spot on. Let's take this off-list and see what's going on. If anyone else has been logging SkyTraq NMEA or binary from the LTE-Lite let us know. Bill Beam NL7F ___ 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] D term (was no subject)
In message CAMQqFumOdB4gcFfQjQ_nced0C_U=fbmyofwl7vuxm8wotqg...@mail.gmail.com , Didier Juges writes: In order to automatically compensate for different oven loading (and ambient conditions), the controller injected a very low level random noise over the temperature setting and by analyzing how that noise was filtered by going through the oven, was able to determine the response of the oven itself and from that optimize the PID terms in real time as a function of the load. This was in the early 80's. It was pretty hot stuff then, even for an oven :) Many off the shelf temperature controllers have an auto-tune button these days which does exactly that: Inject a heat-pulse, see what happens, do math... -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] D term (was no subject)
I'm fairly sure that Jim is right. I never had to worry about PID machine control before the late sixties and by the mid-seventies the concepts were firmly in place and in use. It certainly was the appearance of solid state industrial controls which made it all possible. And those ideas have made possible some system performance that I recall as being impossible only a few years earlier. Lee Mushel - Original Message - From: Jim Lux jim...@earthlink.net To: Poul-Henning Kamp p...@phk.freebsd.dk; Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Monday, January 26, 2015 8:21 AM Subject: Re: [time-nuts] D term (was no subject) On 1/26/15 5:55 AM, Poul-Henning Kamp wrote: In message 54c5a270.7090...@earthlink.net, Jim Lux writes: And there's decades, if not centuries, of experience with P, PI and PID controllers in a practical sense. Not quite a century I belive: Only the advent of electronics formalized the theory and developed the practice. Almost all mechanical governors er pure P. Maxwell strikes again http://upload.wikimedia.org/wikipedia/commons/b/b1/On_Governors.pdf definitely more than P controllers.. cups with liquid (Siemens governor), nonlinear mechanisms, etc. ___ 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.
