Cliff Curry wrote:
This is a problem in general in direct conversion schemes: and this is the
reason that "quadrature" detectors are made, with two mixing channels 90
degrees apart, so that the phasing is no longer a problem. (the sqrt of
sum of squares of the signal out of the two channels (or "magnitude") is
not sensitive to phase.)

Hmm... I went through the math, and indeed, this is the case!

But this then begs the question: Since the quadrature detector obtains the
correct magnitude of the transmitted signal for ANY phase difference between
the carrier and the LO, and if we model the phase difference as a function
of time that slowly changes due to the fact that, in actuality, our LO isn't
_quite_ the same frequency as the carrier, will the system still work? This
almost seems too good to be true...

Thanks,
---Joel Kolstad