> It would be interesting to look at the data to see if you can find the sort
Hi Hal, There's lots of examples of sawtooth patterns at: http://leapsecond.com/pages/MG1613S/ In particular there's this monster: http://leapsecond.com/pages/MG1613S/tic-72-hour.gif It's simple for a microprocessor-based GPSDO with its TIC to realize when it's getting too lost in a hanging bridge. There are a number of ways around the problem. My favorite is gluing a resistor on top of the GPS chip and pumping a few tens of mW through it when you want the bridge to stop. Here's the proof-of-concept: http://leapsecond.com/pages/vp/heater.htm /tvb ----- Original Message ----- From: "Hal Murray" <hmur...@megapathdsl.net> To: "Nick Sayer" <nsa...@kfu.com> Cc: "Discussion of precise time and frequency measurement" <time-nuts@febo.com>; "Hal Murray" <hmur...@megapathdsl.net> Sent: Monday, July 18, 2016 9:41 PM Subject: Re: [time-nuts] How does sawtooth compensation work? > > nsa...@kfu.com said: >> Yes, thatâ?Ts true. Given the facilities I have available with the present >> hardware, I donâ?Tt believe I have much choice. I am not confident that I >> could tell the difference between noise in the phase detection system and >> PPS jitter variations that small. If the PA6H receiver gave sawtooth >> corrections, Iâ?Td be able to do better. > > It would be interesting to look at the data to see if you can find the sort > of pattern that a sawtooth correction would help and where a hanging bridge > might cause confusion. > > If the bridge isn't hanging, the data samples should be spread over a range > that is the clock period of the GPS unit. Round that up to 100 ns. I doubt > if you will see that with a PC. > > On the other hand, you can get the same sort of pattern with a PPS over USB. > That would be a ms wide and easy for a PC to get time stamps much finer > grained than that. > > > -- > 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.