On 2015-02-06, [email protected] <[email protected]> wrote: > On Friday, February 6, 2015 at 3:38:14 PM UTC-6, William Unruh wrote: > >> > Is there any reason why I could not share the PPS output of say, my u-blox >> > 7 GPS module on multiple computers? Would it be good or bad to peer these >> > 2 systems with each other? >> >> By share you mean run the PPS output to each of the computers? The main >> thing you would need to do is make sure that the gps is able to handle >> the current load, and that the signals had the appropriate level at each >> of the computers. > > Yes, exactly what I mean. >> >> >> > >> > On the opposite end of the spectrum, would it be reasonable to have a PPS >> > output from said module on a computer, with a second PPS (from another GPS >> > module) on that same computer? >> >> Sure. you need to have two differnt interrupt lines available (GPIO, >> serial ports, parallel ports) >> > > Awesome! > >> > >> > The Chronodot/DS323X chips have 1 Hz sqaure wave output and they have +/- >> > 2ppm. It seems that the ATOM clock driver could be used, but would it be >> > better to write a driver specifically for this chip? >> >> 2PPM is not that great. That is one second out per 6 day. A minute out >> per year. >> What is that chip. >> > > I was thinking more as a worst case, offline for hours situation. Perhaps a > new driver could 'sync' the Dallas Semiconductor/Maxim DS3231 OXCO Real Time > Chip periodically. > > What is the ppm error of the RTC in a pc or my MacBook?
from a few to many PPM. The uncompensated one can be up to 50PPM. But if you computer is on, and ntp has disciplined the clock and the machines internal temp does not change by much (eg yousuddenly start doing some massive numerical calculation or start playing a game) then you computer itself should be able to do 2PPM without any help. > >> > Does someone know the admin of tick.uh.edu? I am not getting a response >> > from them or the server. >> >> What reponse do you want? Why should they respond to you? > > I would like to use tick.uh.edu as one of my 'local' Stratum 1's. I have 1 > from Oklahoma, but I'm in Texas... and the server is either down, or the name > has changed on Pulic Strat 1's list hasnt been updated. Ah, response from the computer, not response from the people there. Yes, it seems down to me as well. > _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
