>> 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.
