Yes, that is correct.

However, the choice of frequencies in your demod example is likely to give
you other problems not obvious from the basic theory. Harmonics of the 1 MHz
are likely to show up in the 10 (or 12 Mhz) output. There are also likely to
be many mixing products of all of the harmonics of 1 MHz and any other
frequency that can mix with 1 Mhz to produce a 10 (or 12) Mhz output. In
general, it's problematic to make a frequency conversion (mixer) process
where the LO is substantially lower than the output frequency, and
especially so if the LO is an exact sub-multiple of the output.

Joe
W3JDR


"Michael Dunn" wrote in message
.. .
Basic dumb question:

I read this in passing and am not sure I understood correctly. It
seemed to say that you can do image rejection with a quadrature
demodulator (by summing the outputs).

For example, feed 11MHz to an IQ demod running at 1MHz. The I & Q
outputs will each have 10MHz & 12MHz components in them. Sum the
outputs. One of the frequencies will phase-cancel, the other will add
constructively. Is this correct?

thx
Michael
mdunn **at** cantares.on.ca