On Mon, 17 Aug 2009 23:18:58 +1200 Bruce Griffiths wrote: > Steve Rooke wrote: > > 2009/8/17 Bruce Griffiths <[email protected]>: > > > >> [email protected] wrote: > >> > >>> Please, how do time-nuts measure phase noise? What may be a minimal setup > >>> whit recording capability? > >>> Thanks, > >>> Antonio I8IOV > >>>
> >>> > >> snip > 1) Use 3 sources, S1, S2 and X. > > 2) Phase lock S1 in quadrature to X using a diode double balanced mixer > using a low bandwidth PLL. > > 3) Phase lock S2 in quadrature to X using a diode double balanced mixer > using a low bandwidth PLL. > > Then for frequencies outside the PLL bandwidth the crosspower spectrum > of the 2 mixer outputs should be predominantly due to the phase noise X. > > In practice its best if the phase noise of the 2 standards S1, S2 isn't > significantly worse than that of X. > > It is also desirable that both S1 and X and S2 and X be locked at their > respective mixers quadrature point (not necessarily the same as that for > zero dc output) > > Bruce Bruce, is this what actually time-nuts do? This is unpractical for me, as I have not much time for a circuit building project. Moreover, I would be satisfied even with the analysis at a single frequency, not necessarily the whole phase noise spectrum, and with relative but repeatable measurements. So, does it make any sense using a selective voltmeter, such as an HP 3586A or similar? Antonio I8IOV _______________________________________________ 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.
