4 ms·
Interesting! What is the accuracy like when lacking "PPS precision"/Clayface? I'm wondering about the magnitude by which it is off (seconds, minutes, or other).
by boneitis 2y ago
Interesting! What is the accuracy like when lacking "PPS precision"/Clayface? I'm wondering about the magnitude by which it is off (seconds, minutes, or other).
PPS turned up quickly on Wikipedia, so that one is readily answered
> PPS signals have an accuracy ranging from 12 picoseconds to a few microseconds per second, or 2.0 nanoseconds to a few milliseconds per day based on the resolution and accuracy of the device generating the signal.
- lightswitch05 2y agoYou can see for yourself the level of accuracy in the ntpviz output. Notice the units of measurement on the graphs: * Clayface: https://www.developerdan.com/ntp/#./clayface/7-days/ https://www.developerdan.com/ntp/#./clayface/7-days/ * Catwoman: https://www.developerdan.com/ntp/#./catwoman/7-days/ https://www.developerdan.com/ntp/#./catwoman/7-days/ That Wikipedia quote should mention temperature! Temperature variations have a big impact at this level of accuracy. These really cheap GPS receivers do not have temperature adjusted clocks. Unfortunately my server closet (this is just a hobby) does not have well regulated temperature, so you can see the impact of temperature on the clock accuracy. Also, I found if I start running a bunch of stuff on these computers - that makes the CPU heat up, which also affects the jitter. If you really want high-precision, you'll have to shell out some extra cash then I did: https://www.sparkfun.com/products/18774 https://www.sparkfun.com/products/18774
- hcfman 2y agortk gnsses really rock. I would to save up for one for next year :)