Hi My main concern with gradients would be second order effects on the servo circuit. As you change the zero of the phase detector you get a net short term frequency shift. Gradients on the pc board -> stress on smt parts -> value changes -> phase shift.
Bob On Dec 24, 2009, at 8:09 PM, Magnus Danielson wrote: > Bob Camp wrote: >> Hi >> I certainly agree that, say potting the circuit board, would be a lot easier >> than some of the stuff we have been talking about. > > I am not sure that it would significantly improve the case. > > The physical package as a whole, needs temperature stabilization. Double-oven > strategies etc. is among them. At the same time it is a heat source, so we > need to cool a few wats off it. Except for possibly the resonant cavity, I > don't think thermal gradients is as important as stable temperature, where as > the crystal(s) of the electronics boards is another story. The electronics > might enjoy a cooler and somewhat gradient free environment, but for longer > taus most of the effects would be servoed in to the rubidium resonance > anyway, so I suspect most of those long-term effects can be focused on the > physical package. > >> My main concern about tearing up the unit is impacting the magnetic >> shielding. I assume that the outer enclosure forms part of the magnetic >> shield (at least that's what the data sheets say ...). > > Good point. > > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
