That also leads to a thought I've had -- if you have a pair of roughly comparable oscillators at say 5 MHz, what about combining their outputs in a mixer and using the 10 MHz sum output which (apart from noise added by the mixer) ought to be sqrt-2 better than either unit alone?
John ---- Tom Van Baak said the following on 04/06/2008 12:04 PM: >> Actually, in this application will a bit of interlocking not >> hurt, as the two oscillators should longterm have the same >> frequency and interlocking will pull them together to their >> average frequency. If you further aid this interlocking by >> externally couple them together for higher frequencies (up to >> say 10-100 Hz) then you can sum their outputs and get a >> reduced noise response, a 3 dB improvement. The noise >> processes internal to the oscillators will be uncorrelated >> where as the locking causes the signals to be in phase. > > This is very true. I saw that HP did this in their cal lab with a > half-dozen(?) hand-picked 10811 in order to get a combined > virtual OCXO with better phase noise than any one physical > OCXO. Rick, maybe you remember some details of this cool > 10811 ensemble? _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.