On Monday 01 April 2013, Attila Kinali wrote: > On Mon, 1 Apr 2013 14:24:58 +0100 > > Wolfgang <timen...@triplespark.net> wrote: > > Anyway, each of these down-mixing approaches needs to resolve the > > mirror frequency problem. I.e. if you modulate your receiver with > > 7.1 GHz (or use an EOM to do that optically) and detect at 100 MHz, > > you do not know whether the input signal has an offset of 7.2 GHz > > or 7.0 GHz. > > So you might be locking on the wrong one. > > If i'm not mistaken, this shouldn't be a problem > I'm not demodulating the laser, but using a PLL to fix the difference > frequency. Being on the wrong side would invert the sign on the loop > gain, thus the mirror freuquency would be an unstable point. > Without too much of thinking it seems to me that there are 4 cases that show up as 100 MHz. Only 2 of them without the RF mixing. 2 will have the same loop sign (only 1 without RF mixing).
A-B = 7.2 GHz A-B = 7.0 GHz A-B = -7.0 GHz A-B = -7.2 GHz BTW, what's the linewidth of your lasers? -Wolfgang DL1SKY _______________________________________________ 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.