> -----Original Message----- > From: [email protected] [mailto:[email protected]] On > Behalf Of Rick Karlquist > Sent: Thursday, August 13, 2009 3:35 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] OCXO sensitive to gravity > > Tom Duckworth wrote: > > The orientation change is due more to the earth's magnetic flux > effect on > > the oscillator, and less so from gravity. > > > > Tom > > Tom Duckworth > > [email protected] > > Sorry, this is simply incorrect. Magnetic flux from the > earth has no effect on quartz oscillators. There is no > mechanism there. Acceleration definitely affects quartz. > >
Hmm. We're investigating just this at work, in connection with things destined to orbit Jupiter, where we expect to see a periodically varying flux as the spacecraft spins. The quartz is insensitive, but the mounting isn't necessarily insensitive to magnetic fields, especially if any magnetic materials (i.e. Kovar seems to be of interest) are used. If you have any circuits sensitive to DC offsets, then a varying magnetic field can cause problems (e.g. the VCO input in a PLL). I suppose it depends on "how good" the oscillator is expected to be... _______________________________________________ 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.
