Hi all, quick question. In class last term we had learned about how signal transmission worked through modulation/demodulation of frequency responses. Anyway, in order to shift the frequency responses we learned that this can be done by multiplying the signal by a sinusoid (generated by an oscillator).

My question is, what is the circuit that is used to multiply the signal of interest by the oscillator's sinusoid to shift the frequency response into the FM/AM band?

We were just shown the black box but I am just curious.

Thanks!

 

For AM you can use an analog multiplier or non-linear mixer circuit.

For FM you need an FM Modulator, a type of voltage controlled oscillator.