Hi If you have a GPS on your local lan, just use it for the calibration. There’s no need for NTP to get involved.
If you are running NTP over a normal home setup going to the internet, then you will be doing very well to get low ms with NTP. Going back to the original post, the request is for a method to calibrate a newly assembled board. Since we are talking about a generalized calibration procedure, simply saying “use NTP” without mentioning setting up a LAN / GPS NTP empire seems to be a bit misleading. That is a very unique system that the vast majority of the world would not be using. Bob > On Apr 13, 2018, at 2:18 PM, David J Taylor via time-nuts > <[email protected]> wrote: > > Hi > > NTP will give you “millisecond" level accuracy / stability. If you want to > set an > oscillator to 0.1 ppm, you will need to run for over 10,000 seconds. It is not > uncommon to have things out in the 10 ms range. That would put you at > 100,000 seconds. In more common units, a couple of hours to > 1 day > would be needed. > > Keep in mind, this is for a single observation. If you need to make three or > four > tweaks to get things set, the numbers would go up a bit. > > The earlier mentioned GPS approach with a $10 USB dongle would do it a *lot* > faster. More or less, you could expect a bit better than a 1000:1 speed > improvement. > > Bob > ================================== > > With respect, NTP using a GPS/PPS clock can give tens of microseconds or > better, even on a Raspberry Pi. For example: > > http://www.satsignal.eu/mrtg/raspi1_ntp.html > > (The slight downward slope back over time is an artefact of MRTG with small > integers.) > > Cheers, > Davis > -- > SatSignal Software - Quality software written to your requirements > Web: http://www.satsignal.eu > Email: [email protected] > Twitter: @gm8arv > _______________________________________________ > 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.
