Roughly, when you're receiving an AM signal, you use the rectifying effect of a diode coupled to a low-pass filter. The idea is that the envelope is all you rea

Roughly, when you're receiving an AM signal, you use the rectifying effect of a diode coupled to a low-pass filter. The idea is that the envelope is all you really need to pass to the speaker, if the signal itself is powerful enough. http://en.wikipedia.org/wiki/Envelope_detector http://en.wikipedia.org/wiki/Envelope_detector