SOT: FM radio explaination?

[Brian Marshall]

Ok... am radio makes sense to me... vary the amplitude of carrier, and use the change in amplitued to create a sound wave.  easy enough.

FM???  Ive always been curious if this is similar to the way a theramin works.  does it use a differential frequency to create a lower sound wave.  Seem to me this is more like the way old cb sidebands work.  My dad was trying to tell me that the harmonic structure of the carrier is varried, but couldnt tell me much more...

anyone know?

[cd]

http://www.radiodesign.com/radwrks.htm

[Brian Marshall]

so im right... dad was wrong.

so much for him being an electonics engineer with 35 years experience.