[time-nuts] Discipline an oscillator with NTP?

[paul swed]

Yes but zero beat by ear is terrible. Are you talking a scope and I think
thats only 1 X 10-7 as I recall.
Regards
Paul.

On Sat, Jul 23, 2011 at 12:42 PM, Bob Camp <lists at rtty.us> wrote:

> 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 <
> albertson.chris at gmail.com
> >> 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 <jimlux at earthlink.net> 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.
> >>>
> >>> _______________________________________________
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> >>>
> >>
> >>
> >>
> >> --
> >>
> >> Chris Albertson
> >> Redondo Beach, California
> >>
> >> _______________________________________________
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