Hi > On May 21, 2018, at 2:08 PM, Gary E. Miller <g...@rellim.com> wrote: > > Yo Bob! > > On Mon, 21 May 2018 14:00:41 -0400 > Bob kb8tq <kb...@n1k.org> wrote: > >>>> Ok, are you trying to hold close to UTC or simply have a second >>>> that is as close to 1 second as possible? >>> >>> Yes. One follows the other. >> >> Not really, you can have a source of seconds that are all within 0.1 >> ns of the right length but are offset from UTC by 200 ns. ( stable >> but not accurate) >> >> You can have a series of seconds that are all within 10 ns of UTC, >> but one may be 20 ns to short and the next is 20 ns to long. >> ( accurate but not stable ) >> >> So, which of the two is more important? > > UTC is most important (to me), but if one has perfect UTC, then one also > has perfect seconds.
Except that you are doing a design. That involves tradeoffs. Pre-processing a thing message that comes in 800 ms before a pulse does not sound like a big deal to me. In your design it apparently *is* a big deal. If you indeed want very tight UTC, that involves very similar sorts of things. There are a *lot* of delays to be worked out. The offsets between GPS time and UTC need to be downloaded and summed into the servo as well. A GPSDO ( or anything that works like one) will have accurate second to second timing. In a very general sense, it does not care about a time offset. A fixed delay of 100 ns is no different than a fixed delay of 200 ns as far as it’s output or it’s function. So, no, it’s not a drop dead simple choice. Bob > > RGDS > GARY > --------------------------------------------------------------------------- > Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 > g...@rellim.com Tel:+1 541 382 8588 > > Veritas liberabit vos. -- Quid est veritas? > "If you can’t measure it, you can’t improve it." - Lord Kelvin > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.