> -----Original Message----- > From: [email protected] [mailto:[email protected]] On > Behalf Of Bob Camp > Sent: Wednesday, December 23, 2009 9:52 AM > To: 'Discussion of precise time and frequency measurement' > Subject: Re: [time-nuts] Cheap Rubidium > > Hi > > If you can achieve <= 1x10^-13 at 10,000 to 100,000 seconds, that's quite a > bit better than any OCXO has a right to be doing. Yes I know that there is > one in the entire universe that gets close. > > Even if you just do < 1x10^-12 at 1,000 seconds, that's better than a whole > lot of OCXO's will do at that tau. > > The place where the OCXO does come in is < 100 seconds. Between 1 and 100 > seconds you can get a number of OCXO's that will run <2x10^-12 over the > entire range. You can fine a lot more that will do < 1x10-12 over that range > than you can find that will do < 1x10^-12 at 1,000 seconds. The rubidium is > struggling to get to 1x10^-11 at 1 second and may or may not get to 1x10^-12 > at 100 seconds. >
Typical (Cassini, MGS, etc., data from Sami Asmar) UltraStableOscillator (USO) specs as used in spaceflight do about 1E-13 at tau =10 to 1000 seconds, 3E-13 at 1 second. Today, you can probably do maybe an order of magnitude better. These are state of the art oscillators in a vacuum envelope with double ovens, etc. _______________________________________________ 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.
