Hi Peter: Yes, as far as I can tell all oscillators have an adjustment to allow changing their frequency, including the C Filed adjustment on a Cesium standard. The key difference is that with the Cesium standard, by definition, it does not drift. So if you make a phase plot comparing any oscillator to say a timing grade GPS receiver the shape will be parabolic or some higher polynomial. But for a Cesium it will be a straight line.
The more modern Cesium standards have control loops that automatically set the C Field and maintain it so do come very close to the plug and play idea. But the first few generations of Cesium standards need to be tweaked on frequency. The HP 5060 C Field adjustment is so coarse that a modern Rubidium standard is more accurate. http://www.prc68.com/I/5060A.html <- C Field step size near 1E-10 if you use the smallest mark on the vernier of the 10 turn pot http://www.prc68.com/I/FTS4060.shtml <- C field step size near 1E-14, 3 digit thumb wheel. Have Fun, Brooke Clarke http://www.PRC68.com http://www.precisionclock.com Peter Vince wrote: > ); SAEximRunCond expanded to false > Errors-To: [EMAIL PROTECTED] > > Everyone on the 'net agrees on the frequency of the Caesium > oscillation, but the precise frequency quoted for Rubidium varies by > a few Hz :-( Now I realise that you can make it anything you like > (within reason) by altering the magnetic field, and perhaps different > sources quote different figures which are more or less easy to > synthesise? > > On the (USA) NIST web-page > (http://tf.nist.gov/general/enc-re.htm#rubidiumoscillator) they quote > 6,834,682,608 Hz, but the (German) PTB (on > http://www.ptb.de/en/org/4/44/441/info2_e.htm) give 6,384,682,612.8 > Hz, and the (British) NPL quotes 6,834,682,610.904 324 Hz in a > powerpoint presentation > http://www.npl.co.uk/time/club/meeting1/secondaryrepsec.pdf > (admittedly for a Rubidium fountain). > > I have also seen the frequency of a Hydrogen Maser given as both > 1,420,405,751 Hz and ...752 Hz. I would be very surprised if the > frequency was an exact whole number of Hertz different from Caesium, > so perhaps this is just rounded for convenience as again it can be > steered to anywhere you like? > > Would anyone care to comment on this differences please? > > Thank you, > > Peter Vince (G8ZZR, London) > > _______________________________________________ > 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.
