From: Bruce Griffiths <[EMAIL PROTECTED]> Subject: Re: [time-nuts] GPS noise reduction Date: Mon, 07 Apr 2008 09:19:11 +1200 Message-ID: <[EMAIL PROTECTED]>
> Tom Van Baak wrote: > >> 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? > > > > /tvb > > > > > Tom > > Phase noise is also reduced when an oscillator uses several crystals > (with the same resonant frequency) connected in series. Yes, but it only reduces crystal related noise... where as amplifier noise is not reduced. Cheers, Magnus _______________________________________________ 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.