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Jan31-13, 09:01 PM
Sci Advisor
PF Gold
P: 2,080
An ideal mixer multiplies two signals. Use trig identities to write
cos(fm)*cos(fc) = cos(fm+fc) + cos(fm-fc)] / 2
A real mixer is non-ideal and allows some of fc to leak through to the output. (Leakage of fm is far away and is filtered out). Real mixers also produce harmonics and high-order mixing products, which again are filtered away.