Hi
Unless your crystal has been cut for temperature sensing (AC or LC cut) you will have some issues sensing temperature over a very wide region. Bob > On Jul 4, 2015, at 12:45 AM, Brek Martin <bmar8...@bigpond.net.au> wrote: > > > > Hi Guys, > > I feel like I missed “The Big Thing” in time keeping land. I should have > watched my Ublox LEA-5T. > What is the difference if it is in the reporting mode for GPS or UTC time? > If they skip a second UTC, surely the GPS time isn’t run incorrectly forever. > > I’m using the Ublox to synchronise a micro that is clocked with the 10Mz > signal from and Rb module, > and the micro controller keeps time from there. So I currently wouldn’t see a > leap second unless I looked back at the GPS. > > Another idea I had since making a copper thermal mass for the Rb module… If you go back about 6 years ago in the archives, we went through all of the math on thermal mass as a regulator for this sort of thing. A search for “swimming pool full of mercury” may turn it up. Bottom line is that you need a *lot* of mass. A fan / sensor / heatsink / controller combo is a much more effective solution. > A microcontroller clocked with the Rb module should be able to tell the > temperature by counting the frequency > of any other crystal generated clock in the circuit.. not necessarily just > for the Rb thermal mass, but outside environment. > Although the temperature has some effect on the Rb module frequency, it is > less then the effect on Xtal frequency. Unless your crystal has been cut for temperature sensing (AC or LC cut) you will have some issues sensing temperature over a very wide region. Probably the best thing you can easily get would be: 1) An SC cut run on the wrong mode. 2) An AT cut for an OCXO and used to sense in the vicinity of room. Bob > Cheers, Brek. > > > ps. am I replying the way I’m supposed to with a new email and subject? > _______________________________________________ > 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.
