Hi Maybe if we keep the thread alive long enough *somebody* will measure a GPS 16 simply to get rid of us :)
What if you put an accurate clock on the micro that feeds the AND gate ( yes, the one we threw out last message). Let it “flywheel” (= produce it’s own 1 ms accurate pulse) when the GPS goes away. Windows may have trouble with 1 ms sort of stuff. Micros don’t have much trouble in that regard. More or less “substitute” the output of an oscillator you know is good to << 1 ms over 15 minutes when you need it. Bob > On Mar 12, 2019, at 6:20 PM, Steve Olney <[email protected]> wrote: > > Hi Bob, > > On 13/03/2019 1:30 am, Bob kb8tq wrote: >> Sorry if this is an ongoing / somewhat random dump of a bunch of things … I >> am not doing the >> same sort of thing you are doing. That makes a lot of this a bit less >> focused than maybe >> it could be. > > Thanks for your suggestions - they have been most helpful. It was just when > the discussion turned to Maser clocks and interferometry that I was concerned > that the discussion had "dropped out of lock and drifting with many ppm" :-) > > I simply want to know about the behaviour of the GPS 16 HVS under no-lock > conditions. I need that information to optimise a fail-safe mechanism in my > software. Basically, if there is a loss of lock I need to account for that. > In my application, it doesn't matter if the GPS unit drops out of lock as I > can re-schedule the timing event to a slightly later time when a valid fix is > present. All that matters is that I have an accurate time-stamp. It doesn't > matter if that time-stamp is re-scheduled for a minute or two later. > However, if I know the drift of the 1 PPS output under invalid fix conditions > I might not need to reschedule the timing event at all as long as the > (tdrift/dt) * (how long the invalid fix has lasted) < 1 ms. The value of > tdrift/dt is the key to implementing this. > > Thanks for your suggestions. > > Cheers > > Steve > > HawkRAO > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
