I know that this is not germane but I keep thinking of this video: http://www.youtube.com/watch?v=kqFc4wriBvE
32 mechanical metronomes on a moveable floor. They all sync up in a bit more than two minutes. Dave > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Tom Van Baak > Sent: Saturday, December 29, 2012 20:17 > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] ensemble oscillators for better stability > > >> 1) This was a topic some years back -- for internal use, hp tightly > >> combined multiple 10811 oscillators so that the net > phase noise or > >> short-term performance was significantly better than > any one of the > >> constituent oscillators. > > > > Care to share a reference on that? It would be interesting > to see how > > they did it and how well they where doing it. > > Magnus, > > Yes, it came up in a long thread called "GPS noise reduction" > back in April 2008. I'll mention it again -- when I visited > the HP facility in Santa Clara years ago I saw or was told > about a special low noise 10 MHz reference that was used to > measure the phase noise of shipping 10811 oscillators. The > reference itself was a set of several hand-picked 10811's > that were combined in some clever way so that they all > steered themselves creating a coherent single output with > significantly lower noise than any one individual 10811. I > don't have further details but assume the RF and PLL experts > here on the list can figure out what is meant by this and > propose a paper design. It was probably more than 2 > oscillators, but I don't remember now if it was 3 or 6 or > more. Rick Karlquist may also know about this system; either > when/how it was built or what level of performance it delivered. > > /tvb > > > > _______________________________________________ > 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.
