On Mon, 17 Aug 2009 23:18:58 +1200, you wrote:
>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) Has anybody out there already written that cross correlation / user interface stuff? I can / will build a neat multi channel digitizer, perhaps with USB2, but trying to link it to Linux/Windows would probably make it a never ending story. BTW when building the DG8SAQ vector network analyzer <http://groups.yahoo.com/group/VNWA> I had to learn that the sound system of my deLuxe Core Duo motherboard sports ridiculous 40 dB of channel separation. :-( I would also like to try Inphi's sample&holds in front of a decent RF ADC for a direct RF three cornered hat implementation (maybe a ANSI/VITA 57 mezzanine board for a contemporary Xilinx development board), but with all the software it's too much for one person. I have done a new incarnation of my discrete NIST-flavoured distribution amplifier. The input return loss still needs to be cleaned up, then it's ready for publication. Gerhard, DK4XP _______________________________________________ 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.
