Re: [time-nuts] Hydrogen Maser Kit part 3
Corby, that's gorgeous. Can't think of a better man to accept that challenge, tvb excepted. Were I twenty (or 30) years younger, I'd love a challenge like that, but my employer would not allow time for such a project. What I've done while working is accumulate stuff to do when I retire. That happened in 1999, and my task list has been full since then. So it goes. Best regards, Bill Hawkins -Original Message- From: cdel...@juno.com Sent: Friday, December 19, 2014 11:30 PM Hi everyone, The Maser Kit is progressing. Old Teflon removed, Bulb cleaned, Ion pumps ready to test, and curing oven under construction. Details and PIX at: http://leapsecond.com/corby/maser/index.htm#part3 Cheers! Corby ___ 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] Cheap 5370A on eBay
I believe there are 5370 ROM dumps on KO4BB.COM I few years back i posted on this forum how I restored a 5370A that had a missing ROM board by installing an EEPROM into the empty socket on the CPU board. I did have to jumper a couple of address lines to the EEPROM and perhaps tweak the data buffer enable signal... it's been a while. The 5370A normally uses a separate ROM board containing the firmware in several ROM chips. I read out those chips from a good machine and merged the data into a single EPROM. ___ 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] Cheap 5370A on eBay
In message blu170-w651e405ea49cc0fe9e42d0ce...@phx.gbl, Mark Sims writes: I believe there are 5370 ROM dumps on KO4BB.COM They're also in the BBB-5370 repos. I few years back i posted on this forum how I restored a 5370A that had a missing ROM board by installing an EEPROM into the empty socket on the CPU board. I did have to jumper a couple of address lines to the EEPROM and perhaps tweak the data buffer enable signal... it's been a while. The 5370A normally uses a separate ROM board containing the firmware in several ROM chips. I read out those chips from a good machine and merged the data into a single EPROM. One detail to be aware of if you do this, is that the HP5370 uses inverters as address line buffers. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] ESA atomic clocks in space
Fellow time-nuts, Another project to blast atomic clocks into space: http://www.space-airbusds.com/en/press_centre/airbus-defence-and-space-assembles-most-precise-clock-ensemble-ever-for-k0q.html Would not mind a set of those in my lab. Cheers, Magnus ___ 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 Overload, part 2
Hi everyone, In case you didn't notice -- for the past few days the list is in moderation mode -- where all posts are held for review. No worries; we do this now and then. You may continue to post. It just means there will be some delay (minutes to hours) between when you hit send and when (if) it shows up on the list. What's different this time is that off-topic or low content submissions may get lower priority. This should reduce the rate of replies and also encourage posting quality over quantity. The 40, 50, 90 posts per day we have seen of late is unsustainable. Members tune out. Members leave. Something had to change. So one of the goals is getting back to just 10 or 20 interesting and informative time nuts postings per day; on a wider variety of topics; by a wider variety of members, old and new. Thanks, /tvb - Original Message - From: Tom Van Baak t...@leapsecond.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Wednesday, December 17, 2014 1:34 AM Subject: [time-nuts] Time Nuts Overload Hi everyone, The past couple of weeks or month it seems we've had a lot more traffic than usual. This is a reminder that there are 1300 of us and we look forward to rich content on this list. Postings that have little technical content, or are based on guessing, or are just one-liners, or are off-topic, or even rants are fine once in a while -- but when the list gets too busy, like it has recently, this sort of chatter drives good people away. Worse yet, it sets a really bad precedent for newcomers to the list, who might think this sort of casual content is normal, and then they mimic it. That's an exponential disaster in the making. We want to keep old-timers who value their time and we want to welcome new-comers to the wealth of experience, community, and deep information archives that this list offers. But because it's a mailing list and not a web forum, there must be restraint and focus on postings, and especially replies. So please do your part to keep the S/N really high. If you have questions on recent threads that I stopped, or postings that I rejected, or all the off-list emails that I sent this past week, please contact me directly. Also, if you have any suggestions on how else to solve this overload situation I'm all ears! Do not reply to this posting. Reply to me off-list. I'm at t...@leapsecond.com Thanks, /tvb http://www.leapsecond.com/time-nuts.htm ___ 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] Simple AC mains zero-cross detector
Gary n...@lazygranch.com wrote: I try to minimize dangerous voltages. Anyway, the filtering reduces the slew, so you can't have it both ways. Starting with 120v gives you 10x the slew rate that starting with 12v does, whatever filtering you use. If by post processing you are averaging, then you certainly have lost frequency variation data. Averaging is a filter. You will not lose grid frequency variation data unless you average the 60 per second samples for *extremely* long periods of time, because the grid frequency is generated by rotating machinery weighing many tons that can only change frequency very, very slowly. As I noted before, the simple system I described resolves frequency to better than 0.01 Hz in one cycle, so very little averaging is needed to achieve better resolution than anyone really cares about. As long as the averaging function is more agile than the actual grid (and it will be under all practical conditions), all actual grid frequency variations will be preserved. You proposed a method using steep hardware filtering, which presumably you do not think loses frequency variation data. The system I described can easily duplicate whatever filter you propose, in post-processing. So either your proposed system cannot track grid frequency variations, or my [built and tested] system can. You can't have it both ways. If the event is due to noise, you resolved essentially garbage to a microsecond. No, you resolved a grid phenomenon in which grid-nuts are interested to within a microsecond. If you average, you have done filtering. Yes, but for the reasons given above and in the other messages in this thread it is benign filtering that does not obscure any of the grid voltage features grid-nuts are trying to record. Furthermore, it is done in post-processing so you can re-do it at will to resolve whatever you want to resolve. You proposed a scheme with steep hardware filtering, which does not have this flexibility. This is getting tedious. If you are interested in grid logging, please build one of the simple systems I described and one of whatever system you think will work better, and present data to support your conjectures. Until then, you really aren't contributing anything useful to the discussion. Best regards, Charles ___ 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] Simple AC mains zero-cross detector
Yes, PMUs makes it a bit different. Here is a random paper someone wrote: https://rubidium.dyndns.org/~magnus/papers/KTH_paper1.pdf PMUs samples at some high frequency, mixes down the network frequency to base-band, filters away the mirror frequency before sub-sampling it into the configured sample-rate. The process is being controlled by the IEEE C37.118.1 standard, while the communication is described in IEEE C37.118.2 but an IEC 61850 extension provides for another way of conveying that data. PMUs have proven themselves to outperform many of the normal frequency and ROCOF estimators, which became evident in the 2003 NE black-out scenario, as the SCADA data kept getting them on the wrong tracks, so after 8 months they just scrapped the frequency readings from the traditional equipment and just looked at the PMU data, they could sort the events out properly in time. Turns out that the details of how a particular vendor implements the frequency estimation and filtering can be devastating in getting comparable frequency measures, and thus loosing the observation precision needed to follow the aftermath properly. The C37.118.1 has put a stringency on how filtering is to be done, as well as how frequency and ROCOF (Rate Of Change Of Frequency) is to be calculated. NIST has a small department focusing on the calibration of PMUs, and is working actively with the vendors to get them improved. Good folks and I have helped them a little with some ideas, amongst others to do through-zero calibrators. For other events, Digital Fault Recorders (DFR) is being used. They are essentially memory oscilloscopes which have a more advanced trigger adapted to go off on all interesting events. Today DFRs is a legal requirement in some countries. So, I do not completely agree that a through-zero measurement with a TIC has all the information, and for the information you do get, you would like to be as careful as the PMU folks about the group-delay of filters, time-compensation of processing and filters etc. to maintain good precision. There is reason to look at it and learn. Cheers, Magnus On 12/18/2014 11:59 PM, Mike Garvey wrote: There is an interesting article in the Nov/Dec issue of Inside GNSS describing the robust measurement of ...voltage and current phasors at widely dispersed locations in a power grid. A Phase Measurement Unit measures and time stamps the voltage and current phasors ...thousands of times per second... to an accuracy of 1 us using GPS. The authors discuss several strategies for dealing with jamming and spoofing of the civil GPS signals. It's a good read. See http://www.insidegnss.com/node/4281 Mike -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Hal Murray Sent: Wednesday, December 17, 2014 3:28 AM To: Discussion of precise time and frequency measurement Cc: hmur...@megapathdsl.net Subject: Re: [time-nuts] Simple AC mains zero-cross detector csteinm...@yandex.com said: That one is not ideal for this task, because (i) its output pulse is symmetrical about the mains zero cross, and (ii) the hysteresis zone is not well characterized and will drift with temperature and input voltage. So, there is no edge that is well characterized in relation to the AC mains zero cross. What are you going to do with data from the line accurate to 1 microsecond? -- These are my opinions. 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. ___ 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] KS-24361 adjustable PLL time-constant
I know these has been discussed to death here, so my apologies for that. Also, apologies if this has already been reported; i did not find it in the archives.. It might be of interest to some that it appears that the KS-boxes has an adjustable PLL time constant: :SYST:LANG PFORTH pll_rep start ptr = 0stop_ptr = 0 max loop time = 700 ffom = 1 tfom = 1.0e-06 secs 1000 loop_time pll_rep start ptr = 0stop_ptr = 0 max loop time = 1000 ffom = 1 tfom = 1.0e-06 secs Looks like a teakable PLL parameter, but I don't have the measurements to back it up. Yet. Also, there is a command to report on the L1-status, which might make life easier for those who try to get the boxes going separately by manipulating the J5-port: On REF-0 print_l1 mode: locked, duration: 1152 locked duration: 1153, learning exceeded: 0 ready: 1, critical failure: 0 shutdown failure: 0 GPS locked once: 1 GPS found once: 1 Flywheel capable state: 0, time: 3600 sec Other flywheel capable state: 2, time: 28800 sec flywheel ready mode: idle Other GPS locked once: 1 other on: 1, delayed other on: 1 Monitor enable active: 1, ready: 1, hold actref: 1 ext_1pps_dead: 1 ext 1pps valid: 0 gps_1pps_dead: 0 gps 1pps valid: 1 HW lines cable 1, active in: 0, ready in: 1 Ext locked in: 0, GPS Locked once in 1 ACTREF out: 1, PRI_ACT out: 1 Int power: 0, Ext power: 0 - on REF-1: mode: locked, duration: 76342 locked duration: 76343, learning exceeded: 0 ready: 1, critical failure: 0 shutdown failure: 0 GPS locked once: 1 GPS found once: 1 Flywheel capable state: 2, time: 28800 sec ref duration: 100 other on: 1, delayed other on: 1 Monitor enable active: 1, ready: 1, hold actref: 0 ext_1pps_dead: 0 ext 1pps valid: 1 gps_1pps_dead: 0 gps 1pps valid: 1 HW lines cable 1, active in: 1, ready in: 1 ACTREF out: 0, PRI_ACT in: 0 Int power: 0, Ext power: 0 OleP ___ 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] Simple AC mains zero-cross detector
Charles, On 12/20/2014 09:24 AM, Charles Steinmetz wrote: Gary n...@lazygranch.com wrote: I try to minimize dangerous voltages. Anyway, the filtering reduces the slew, so you can't have it both ways. Starting with 120v gives you 10x the slew rate that starting with 12v does, whatever filtering you use. If by post processing you are averaging, then you certainly have lost frequency variation data. Averaging is a filter. You will not lose grid frequency variation data unless you average the 60 per second samples for *extremely* long periods of time, because the grid frequency is generated by rotating machinery weighing many tons that can only change frequency very, very slowly. As I noted before, the simple system I described resolves frequency to better than 0.01 Hz in one cycle, so very little averaging is needed to achieve better resolution than anyone really cares about. As long as the averaging function is more agile than the actual grid (and it will be under all practical conditions), all actual grid frequency variations will be preserved. As you look careful on the phase variations, you will find that you have forced oscillations being pushed onto the network, some extending into several hertz and in one case a wind-farm had a 13 Hz forced oscillation being pushed out on the power grid. Also, there is inter-area oscillations creating resonant modes on the power-grid. These can either be fed from generators injecting energy into the mode or cause variations as breakers, transformer tappings or change of load occurs. Things have been discovered when looking deeper into the phase variations with faster speeds. Besides doing wide-area monitoring, starting to use these observations to steer stabilizers have been discussed and tested. The development goes quickly in the power-grid world at the moment. Cheers, Magnus ___ 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] Cheap 5370A on eBay
On 12/19/2014 10:40 PM, Mark Sims wrote: I few years back i posted on this forum how I restored a 5370A that had a missing ROM board by installing an EEPROM into the empty socket on the CPU board. Based off of that, I did similar, and documented it here: http://www.flatsurface.com/5370A/ ___ 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] Homebrew frequency counter, new board test result
Hi It's me again. I was debugging the new FPGA version board this week. The attached file is the test result of this new board, and 2 tests of CPLD version(2014/12/11) are also included. There are few things changed between these 2 version: 1) CPLD - FPGA 2) XC6206 - TPS79333 for TDC power supply. Analog and digital part of TDC use dedicated LDO. 3) 2 layer - 4 layer 4) add 74ALV2G14 since FPGA does not support schmitt input A little bit better than before. :) mistakes of current version: 1) the board is 1cm bigger than expected... 2) the themral pad of FPGA should be connected to ground test instruments 1) HP6622A as power supply 2) FE5650 rb as reference 3) PRS10 rb as DUT Li Ang ___ 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] Homebrew frequency counter, new board test result
Hi On Dec 20, 2014, at 10:28 AM, Li Ang lll...@gmail.com wrote: Hi It's me again. I was debugging the new FPGA version board this week. The attached file is the test result of this new board, and 2 tests of CPLD version(2014/12/11) are also included. There are few things changed between these 2 version: 1) CPLD - FPGA 2) XC6206 - TPS79333 for TDC power supply. Analog and digital part of TDC use dedicated LDO. good idea 3) 2 layer - 4 layer also a good idea 4) add 74ALV2G14 since FPGA does not support schmitt input I would suggest trying it with a non-schmitt trigger part as well. It should be a simple swap out since it’s a leaded part. In some cases the trigger level hysteresis is not helpful. The better over voltage immunity of the leaded parts compared to the FPGA inputs *is* a good idea. They also are a lot easier to swap out if you blow one out accidentally. A little bit better than before. :) Yes indeed. Not just better in magnitude, but better in terms of the traces all being close to each other. mistakes of current version: 1) the board is 1cm bigger than expected……. so you got some board for free :) 2) the themral pad of FPGA should be connected to ground Often multiple via’s are run to ground from the thermal pad to improve heat spreading. If the part is not hot to the touch, you should be ok for right now. test instruments 1) HP6622A as power supply 2) FE5650 rb as reference 3) PRS10 rb as DUT I would toss an OCXO or two into the mix eventually. ——— It looks like the three “4 layer FPGA” plots all cluster tightly at just under 2x10^-10 at 1 second as long as linear regression is turned off. That’s pretty good performance. I *think* I’m seeing that correctly on the plots. If I’m not, let me know. The two plots with linear regression are still a bit “interesting”: The plot with ref and DUT the same ( green) still is showing data that is in the “to good to be true” range. The averaging process of the linear regression is probably still causing this. The plot with ref and DUT not the same (RED) shows some sort of spur. That could indeed be a spur from one or the other of the Rb’s. It also could be something in your lab. Turning out the light is a good thing to check. Because of the low frequency, I would suspect a spur on the Rb. Put another way, the counter is not making a mistake in this case. It’s reporting what is actually going on with the inputs. Another test source (or pair of sources) would help sort this out. The ADEV of a (working) MV89 or similar OCXO over the 1 to 100 second range should be at the 2x10^-12 level. That’s good enough for the tests you are running. It’s also well below the (maybe) 1x10^-11 of the Rb’s at 1 second. So far the Rb’s ADEV has not been a problem for you. If you get a bit better with what you are doing, it may become an issue. You will need to use TimeLab’s built in “remove frequency error (drift)” capability when you are running OCXO’s. That’s an ok thing to do for the test. —— Something else to look at: Check your results vs input level. In other words, attenuate one of the input signals and see what happens. I would start with 3 or 6 db and go from there. The attenuation does not have to be precise. The frequencies involved are not high enough to require fancy parts. The idea is to check if the input noise level of the gates is a problem for you. If the data quickly get worse as you attenuate, they need some help. Enough for now. Thanks for sharing !! 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] KS-24361 adjustable PLL time-constant
Hi On Dec 20, 2014, at 10:26 AM, Ole Petter Ronningen olep...@gmail.com wrote: I know these has been discussed to death here, so my apologies for that. Also, apologies if this has already been reported; i did not find it in the archives.. You are the first to dig into the PFORTH side of this box. It might be of interest to some that it appears that the KS-boxes has an adjustable PLL time constant: :SYST:LANG PFORTH pll_rep start ptr = 0stop_ptr = 0 max loop time = 700 ffom = 1 tfom = 1.0e-06 secs 1000 loop_time pll_rep start ptr = 0stop_ptr = 0 max loop time = 1000 ffom = 1 tfom = 1.0e-06 secs Looks like a teakable PLL parameter, but I don't have the measurements to back it up. Yet. The key would be to find the magic report that shows the current PLL setting. They likely push it out to max a bit at a time. If it does get to the max, then indeed bumping it up might be a good idea. Something like “current pull” could be the key here. To have full control you also would need to find the table (or formula) for the P,I, and D values associated with each time constant. Also, there is a command to report on the L1-status, which might make life easier for those who try to get the boxes going separately by manipulating the J5-port: On REF-0 print_l1 mode: locked, duration: 1152 locked duration: 1153, learning exceeded: 0 ready: 1, critical failure: 0 shutdown failure: 0 GPS locked once: 1 GPS found once: 1 Flywheel capable state: 0, time: 3600 sec Other flywheel capable state: 2, time: 28800 sec that one suggests that the two boxes know a bit about each other. It’s also possible they simply are timing the same event. flywheel ready mode: idle Other GPS locked once: 1 other on: 1, delayed other on: 1 Delayed on probably is the flash back and forth sequence at startup. Monitor enable active: 1, ready: 1, hold actref: 1 ext_1pps_dead: 1 ext 1pps valid: 0 gps_1pps_dead: 0 gps 1pps valid: 1 HW lines cable 1, active in: 0, ready in: 1 Ext locked in: 0, GPS Locked once in 1 ACTREF out: 1, PRI_ACT out: 1 Int power: 0, Ext power: 0 A bit of work could put names with the pins on the connector. Here are a few guesses: cable = pin 3, goes to ground on pin 13 on ref-1, low is shown as 1 in the report above int power = pin 10, goes to pin 6 on ref-1, (17/23 dbm switch), low shown as 0 in the report above ext power = pin 6, pin 10 on ref-1, “ ACTREF out = Ext locked = Ready in = … (guess 2,14 below, low reported as a 1) signaling pairs left are: 2,14(low,low) 4,12(low ,high) 7,9 (low,high) Simply based on the (low,low) the Ready in / out pair would appear to be 2,14. That’s on the assumption that both report the same (see below). It’s a coin flip in terms of the other two. - on REF-1: mode: locked, duration: 76342 locked duration: 76343, learning exceeded: 0 ready: 1, critical failure: 0 shutdown failure: 0 GPS locked once: 1 GPS found once: 1 Flywheel capable state: 2, time: 28800 sec ref duration: 100 other on: 1, delayed other on: 1 That’s not the same report as the other one. The boxes know what they are and run different code or the report changes based on who’s active. Monitor enable active: 1, ready: 1, ready out shows the same as ready on the other box. hold actref: 0 ext_1pps_dead: 0 ext 1pps valid: 1 gps_1pps_dead: 0 gps 1pps valid: 1 HW lines cable 1, active in: 1, ready in: 1 ready in shows same as the other box Bob ACTREF out: 0, PRI_ACT in: 0 Int power: 0, Ext power: 0 OleP ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Looking for J1 pinout newly purchased 10811D
Hi, the HP 10811D I just purchased (one like ebay #300568433895) resides on a small pcb. Could someone pls guide me which voltage for the LM317 feeding the oscillator with 12V should be applied at J1/1 and J1/2 ? I would also be interested to learn for which devices these board were originally made - couldn't find anything. Thank you in advance Ulli ___ 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] Looking for J1 pinout newly purchased 10811D
Mod Mix wrote: Hi, the HP 10811D I just purchased (one like ebay #300568433895) resides on a small pcb. Could someone pls guide me which voltage for the LM317 feeding the oscillator with 12V should be applied at J1/1 and J1/2 ? I would also be interested to learn for which devices these board were originally made - couldn't find anything. Thank you in advance Ulli Without knowing anything about the item in the Ebay listing, I can tell you that the input to the regulator supplying the 10811 oscillators in many HP counters is specified to be +15 - +18 Volts. Actually, any voltage within the rated input voltage range of the LM317 regulator is OK, so long as the power dissipated by the LM317 remains reasonable. Cheers, Dave M ___ 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] Looking for J1 pinout newly purchased 10811D
Thanks, Charles. The board should have a part number etched in copper, of the form 0-y. should be the instrument model number. 08770-y is etched in copper = 8770A Arbitrary Waveform Synthesizer. 8770A spec: REFERENCE OSCILLATOT (10 MHz Quartz) Aging rate 5 x 10^^-10/day Makes sense. Ulli ___ 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] Looking for J1 pinout newly purchased 10811D
Ulli wrote: I would also be interested to learn for which devices these board were originally made - couldn't find anything. The board should have a part number etched in copper, of the form 0-y. should be the instrument model number. Best regards, Charles ___ 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] Simple AC mains zero-cross detector
Magnus wrote: So, I do not completely agree that a through-zero measurement with a TIC has all the information No, a series of time-stamped zero crossings doesn't have all of the information in the original signal, and a small glitch that occurs during the middle of a cycle (far away from a zero cross) could hide and show nothing more than a slight displacement of one or two zero crosses. Grid-nuts can ignore such short glitches. Utilities can't, particularly in today's cybersecurity environment. Horses for courses. From my observations of the AC mains while I was testing the simple ZCD, I would expect such hidden glitches [that are real grid-related phenomena, not just someone starting a motor downstairs] to be very rare. The grid phenomena I saw typically last more than one grid cycle and thus affect more than one zero cross, and/or are large in magnitude and cause serious displacement of at least one zero crossing, or several extra zero crossings. Best regards, Charles ___ 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] Simple AC mains zero-cross detector
From a Time-Nut perspective, isn't phase/frequency of the (nominal) 60 Hz all we'd be interested in? Phase is best measured at a zero crossing as this is the (only) phase measurement point which is independent of amplitude. Mike -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Charles Steinmetz Sent: Saturday, December 20, 2014 4:57 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Simple AC mains zero-cross detector Magnus wrote: So, I do not completely agree that a through-zero measurement with a TIC has all the information No, a series of time-stamped zero crossings doesn't have all of the information in the original signal, and a small glitch that occurs during the middle of a cycle (far away from a zero cross) could hide and show nothing more than a slight displacement of one or two zero crosses. Grid-nuts can ignore such short glitches. Utilities can't, particularly in today's cybersecurity environment. Horses for courses. From my observations of the AC mains while I was testing the simple ZCD, I would expect such hidden glitches [that are real grid-related phenomena, not just someone starting a motor downstairs] to be very rare. The grid phenomena I saw typically last more than one grid cycle and thus affect more than one zero cross, and/or are large in magnitude and cause serious displacement of at least one zero crossing, or several extra zero crossings. Best regards, Charles ___ 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] DeLorme Tripmate GPS receiver
I just picked up an old DeLorme Tripmate GPS receiver for cheap, and am wondering if it can be used for getting a 1 PPS signal. I looked online a little and found it's pretty common, but didn't see anything about getting deep into the guts. Most hacks seemed to be about getting it powered up, fooling it into starting up (apparently the character string ASTRAL has to be sent to it), and running to output navigational info (NMEA). The interface is a DB-9 serial connector that I suppose went to a PC and nav software. I don't care about that, and I don't want to even talk to it - just whether it can be fired up and automatically running with an internal mod, to get a 1 PPS out, without ASTRAL or anything else. Does anyone know or have info about this aspect, or info about the guts - block diagrams, sub-modules, documents, schematics, etc? I haven't opened it up yet, but will soon see what's in there. Ed ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Cheap 5370A on eBay
On Sat, Dec 20, 2014 at 12:12 AM, Poul-Henning Kamp p...@phk.freebsd.dk wrote: In message blu170-w651e405ea49cc0fe9e42d0ce...@phx.gbl, Mark Sims writes: I believe there are 5370 ROM dumps on KO4BB.COM They're also in the BBB-5370 repos. I few years back i posted on this forum how I restored a 5370A that had a missing ROM board by installing an EEPROM into the empty socket on the CPU board. I did have to jumper a couple of address lines to the EEPROM and perhaps tweak the data buffer enable signal... it's been a while. The 5370A normally uses a separate ROM board containing the firmware in several ROM chips. I read out those chips from a good machine and merged the data into a single EPROM. One detail to be aware of if you do this, is that the HP5370 uses inverters as address line buffers. I suppose that would affect the order in which you merge the ROMS into a single (E)EPROM, but that's hardly necessary any more. The images in the BBB repos are in the reversed order necessary for programming a new ROM. I had to reverse the order to disassemble the code... ___ 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.
