Frequency modulation
Frequency Modulation (usually shortened to FM) is a way of broadcasting radio signals. The sound quality of FM signals is better than that of amplitude modulation (AM) signals. However, FM signals do not travel as far as AM.
Many radio stations send out both kinds of signals, reserving AM for talk shows, and FM for music. In addition, FM is usually sent as two signals (with one signal's frequency a little lower than the other), which can come to two different speakers in a home. This creates FM stereo sound.
