Hi Backing up a bit ….
If this is all about a system that can quantize to 52 ns at best … your ADEV plot shows everything *well* below that at all offsets you display. If you assume a +/- 1 LSB sort of quantization, you are out to 104 ns. That’s 10X anything on the plot. You would very much need to dig into just how the i/o structure on the device actually handles asynchronous inputs to be sure of what it really is doing. There are a lot of “debounce / re-synch” sort of structures that get pasted into devices these days. Bob > On May 21, 2018, at 3:21 PM, Gary E. Miller <g...@rellim.com> wrote: > > Gregory! > > On Mon, 21 May 2018 19:06:17 +0000 > Gregory Maxwell <g...@xiph.org> wrote: > >> My best guess is that the magnitude of sawtooth error is just not >> large enough to matter for typical applications of linux PPS. > > No need to guess. I recently posted that the RasPi 3B granularity is > 52 nano Seconds and the PPS offset reported by UBX-TP is double that! > > So, clearly it matters. > > I'll do more data logging to get harder numbers. > > 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.
