Hi The simple answer is that normal NTP via the net will give you accuracy similar to the "zero beat to WWV" approach. It will take a few days to get to that level. Much faster to fire up the radio and use WWV.
Bob On Jul 23, 2011, at 12:29 PM, paul swed wrote: > I may be reading way to much into the question. > But the goal discipline the local oscillator as an alternate to GPS or WWVB > etc > Further assumption get the same types of services out of the oscillator > Frequency and time plus pulses. > > That said if its one ntp source you look at, potentially far down stream > with many network hops, doesn't that make your reference only as good as > that ntp server as it jitters around? > > Would it be better to track say 3 servers hopefully up toward the top of the > ntp service. Analyze their behavior to each other to attempt to account for > network behaviors and the server behaviors. > > Essentially compare all three and derive a number to adjust the local > oscillator. > > I might add that by adding any 1 pps source from radio or GPS while > available would really let you understand what jitter and path delays you > are getting and then establish the adjustment. (Fully understand that the > path is variable in IP. > > Love simple but I suspect, its much tougher then that otherwise why mess > with GPS at all. > ;-) Its that darn radio stuff. > Regards > Paul > WB8TSL > > > On Fri, Jul 22, 2011 at 10:25 PM, Chris Albertson <[email protected] >> wrote: > >> Yes but in this case it really is easy; Below is an outline (don't >> try to compile it.). It has a slight problem because just using >> "sleep" is kind of simplistic. One should wait on the new second and >> add some error chacking Point here is just to show that this is not >> weeks and weeks worth of work". The below pulse a bit every second >> and if the system is running NTP then the length of a second is >> controlled by NTP. >> >> Main() >> { >> int status; >> int fd; >> int pw = 1000 /* pulse width in uS */ >> fd=open("dev/tty",O_RDWR); >> while(1) { >> status = 1; >> ioctl(fd, TIOCMSET, &status); >> ussleep(pw); >> status = 0; >> ioctl(fd, TIOCMSET, &status); >> ussleep(1000000-pw); >> } >> } >> >> On Fri, Jul 22, 2011 at 6:08 PM, Jim Lux <[email protected]> wrote: >>> On 7/22/11 3:46 PM, brent evers wrote: >>>> >>>> "After that all you need to do is write some code to..." >>>> >>>> Oh - if I had a nickel for every time I've heard that! >>>> >>>> Brent >>>> >>> >>> When I worked in the physical effects business, we'd get a set of >>> storyboards from a director, and we'd have to figure out how we were >> going >>> to build a rig or arrange the effect as required. The catch phrase was >>> always "then, all you gotta do is"... >>> >>> representing some sort of incredibly difficult, tedious, or impractical >>> activity. Sure, install 10,000 lightbulb sockets into a frame and wire >> them >>> up before tomorrow morning's call time at 6AM.. *all you gotta do* is get >> 50 >>> people to each wire 200 sockets, screw in the bulbs and test them. >>> >>> _______________________________________________ >>> 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. >>> >> >> >> >> -- >> >> Chris Albertson >> Redondo Beach, California >> >> _______________________________________________ >> 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. _______________________________________________ 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.
