Modulation/demodulation with mixers

in a mixer, if a sinusoid is applied to RF port, I suppose the modulation/demodulation is AM.
How is an FM or digital modulation/demodulation performed in a mixer ?

If you have two mixers, you can make an IQ demodulator and feed that into your baseband chip for digital demodulation.

Your RF is actually = Mod +RF. So when you go thru a mixer you get
(RF+Mod) - LO. And LO ~= RF . So your IF ~= Mod Signal. This is a simple case
where it's true if this where a Direct Conversion System.

Just remember that the IF output of the mixer will spit out what ever LOW
Freq Modulation that was Summed on the RF Carrier.

In AM modulation the modulator is a multiplier i.e. a mixer.
In digital modulation the mixer is just a part of the whole modulator/demodulator.
In FM modulation the modulator is basically a VCO, so if you send an FM signal to a mixer you have just upconversion or downconversion.


Bye