The splitter makes two identical signals from Ref 1 The quadrature hybrid makes two signals out of Ref 2, but with a 90 degree phase shift between the signals.
It's essentially a QPSK Demodulator, but set up to run in the linear region, rather than clipping. It's also sometimes called an I-Q detector. There is some closely related info here: http://www.minicircuits.com/pages/pdfs/mod11-2.pdf -John =============== > My attempt to understand your diagram, not sure about how the quadrature hybrid > is connected. > > Stanley > > > > ----- Original Message ---- > From: J. Forster <[email protected]> > To: Discussion of precise time and frequency measurement > <[email protected]> > Sent: Sun, July 25, 2010 10:29:23 AM > Subject: Re: [time-nuts] Basic question regarding comparing two > frequencies > > There is a cute way to use a scope. > > It requires a power splittere, a quadrature hybrid, and two mixers (all appropriate for the frequencies you are comparing), and an X-Y scope. Mini-Circuits sells appropriate parts. The stuff is hooked up like this: > > > X Axis > S | H > P ---- MIX ---- Y > REF 1--L B -- REF2 > I ---- MIX ---- R > T | I > Y Axis D > > The 'scope display will be roughly a circle if the frequencies are a bit different and the spot will go around CW or CCW depending on which Ref is > higher. > > -John > <snip> _______________________________________________ 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.
