On 2011-09-04, Chris Albertson <albertson.ch...@gmail.com> wrote: > On Sat, Sep 3, 2011 at 4:34 PM, A C <agcarver+...@acarver.net> wrote: > >> What I meant was what method is the best way to determine the value of >> time1. > > > That is what I meant above when I said, setting it is easy. Knowing > what to set it the is the hard part. The simplest way is to connect > with a few pool servers then "Fudge" your GPS' time for best match to > the Internet servers.
Since the pool servers are a few orders of magnitude worse than PPS, that would not be a vary useful way. > > The get better then that means you need a trusted source of UTC time. > For most of us that would mean having a "few" GPS receivers of > different brands and times and hardware (Like a Universal Counter) > that can measure the phase between PPS signals. When you get to this > level you are going to have to measure cable lengths. The main problem is actually getting the signal into the computer (interrupt service routines for example). When I tested that time scale was something like 1-2 us. (I times it by timestamping when I sent a signal out on a parallel port pin which was connected to the interrupt pin on the parallel port. the two timestamps tended to be 1-3usec apart). _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
