FM Broadcasting (1 Viewer)

[AmyLeeIsGod]

Sorry if this sounds ignorant but I am really bad at Physics (it's going to be my downfall in my HSC marks).

But, how does FM convey both the frequency (pitch) and the amplitude (loudness) of the imposed audio signal?

 

[alcalder]

No, it's not ignorant. I did a whole year of this at Uni and it still evades me (mind you the lecturer was terrible, so that could be part of it).

http://en.wikipedia.org/wiki/Frequency_modulation

The signal wave (amplitude and all) is superimposed on a set carrier frequency (let's say 104.9 MHz ). When those two are added, the amplitude of the actual signal is incorporated into the outgoing signal by the superposition. Obviously, there could be some clipping of the outgoing signal if it's amplitude, when superimposed on the carrier frequency, exceeds that allowed in the outgoing signal.

At the other end the radio signal is pulled back out of the carrier wave and that's what you hear. There is some tricky technomagic that does all that, but I hope that very simple explanation helps (Oh, I feel inspired to pull out those Uni notes and see if I can finally understand it properly ).