Creative Speculation

Last edited Thu Nov 7, 2013, 02:09 PM - Edit history (2)

In radio, a high-frequency carrier signal is modulated (made louder and softer) at audio frequencies. The high-frequency component is stripped off by the receiver, and the audio remaining is amplified so you can hear it.

Another way microwaves can be modulated is by interference of two microwave signals. This can generate interference "beat frequencies" at the frequency of the difference in frequency between the two microwave signals. So by changing the frequency of one of the interfering microwave beams, you can generate audio beat frequencies.