Hi Observing a curve and being able to compensate it are often two different things. Hysteresis is one very obvious example. Another is simple sensor lag. A some what less obvious one is that the temperature performance is also influenced by the rate of change in temperature.
Here's another thing to consider: If your crystal is running 3 ppm / C, and you are after 3.0 x 10^-11 stability at one second - You will need to either have a rate of change at ~ 1x10^-5 C/sec (0.6 mC / min) or you will need to compensate for some pretty small changes. That of course makes a bunch of assumptions …. Bob On Aug 31, 2012, at 11:26 PM, Jim Lux <jim...@earthlink.net> wrote: > On 8/31/12 7:16 PM, Bob Camp wrote: >> Hi >> >> Ok, that gets you back to the basics of really major delta F / delta T >> slopes. >> >> Bob >> > yeah.. but as long as you know what the curve is.. the NCO has a huge range > (after all, we already have to tune over >500 kHz...a few hundred Hz isn't a > big deal. > > > A more complex problem is doing insitu calibration from, e.g., GPS signals or > from some externally received frequency reference. (since the radio in > question can also work as a GPS receiver, eventually). > > > > > _______________________________________________ > 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.
