Hi If you feed two identical signals into a double balanced mixer, you get 2X the input frequency and a DC component as the “ideal” outputs. You also have the input feed through and N x the input bouncing around as “non-ideal” signals. ( = the full expansion has a *lot* of terms in it).
A normal ( = saturated inputs) diode ring double balanced mixer has a non-linear transfer function for the DC output. As you shift phase, an ideal mixer would have a sine wave voltage vs phase plot. A saturated mixer has something that looks more like a clipped triangle wave as it’s plot. So, simple answer is that single double balanced mixer does not do a very good job as a wide range phase detector. It’s great for phase noise (when properly set up), but not ideal for an unlocked system. Bob > On Apr 27, 2020, at 4:08 AM, Taka Kamiya via time-nuts > <[email protected]> wrote: > > I have a question on heterodyining concept. > Say you have f1 and f2. Say you have f1 <> f2. Then the product is |f1+f2| > and |f1-f2|. (fundamental is not considered here) > What would happen f1 = f2? If phase is the same, it will be 2sin(omega t). > (amplitude doubles) If phase is an odd multiple of pi radian different, > result is zero. (cancels out each other) > What I am trying to do is to first, understand this in case where f1 = f2, > and second, mix f1 and f2 and get f3, which is a sum of f1 and f2. Doubling > won't do. > Can someone help me understand this? I haven't seen discussion of cases > where source frequencies are equal anywhere. > > > > --------------------------------------- > (Mr.) Taka Kamiya > KB4EMF / ex JF2DKG > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
