I would say my implementation is simpler than Nick’s: https://www.eevblog.com/forum/projects/lars-diy-gpsdo-with-arduino-and-1ns-resolution-tic/?all . It is just an Arduino+ two HCMOS and a few passive components. >From the beginning Nick copied my interpolator. Later he added a FET that >might act as a constant current generator but I doubt it works very well. At >least the variance of the FET’s are to large. The temperature stability is not >that good either. So far I have not seen any tests of this. The Elektor GPS by >Joost Breed copied Nick’s interpolator and a graph from that shows large >non-linearities as I can see. My simple interpolator that I linearize in software is not perfect but able to get down to about 1ns linearity by setting min-max and a square term. By using Tom Van Baak’s PICDIV 26 it is fairly easy to set the linearity. Information is in the instruction found on EEVblog. In the last pages I also enclosed ADEV, TDEV and a frequency plot direct from Timelab that works very well with the controller. ADEV at 1s is 8E-10. Also I don’t think Nick sends out the ns direct (absolutely not linearized) on the serial port as I do. As I said before this works very well with timelab. After a lot of testing I also thinks both my hardware and software is robust. Otherwise I would recommend the TAPR-TICC that I nowadays use more than my 5370. Good resolution and much lower power dissipation. Lars
>From: Attila Kinali<mailto:[email protected]> Sent: den 3 april 2018 21:04 On Tue, 3 Apr 2018 10:47:37 -0700 "Gary E. Miller" <[email protected]> wrote: >> What would you guys suggest as the cheapest way to see jitter down to >> around 1 nano second? Look at Nick Sayers GPSDO and his interpolator. You wont get any cheaper than that. Next best thing is to use a TDC7200 like in the TICC. Of course, you will need a standard that is stable enough on the time scales you are looking at. Which is for short taus (<100s) a good OCXO and for 1s to 10ks an Rb, and beyond that a Cs beam standard or hydrogen maser. Attila Kinali -- <JaberWorky> The bad part of Zurich is where the degenerates throw DARK chocolate at you. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
