FM broadcasting

FM broadcasting is a method of radio broadcasting using frequency modulation (FM). Invented in 1933 by American engineer Edwin Armstrong, wide-band FM is used worldwide to provide high fidelity sound over broadcast radio. FM broadcasting is capable of higher fidelity—that is, more accurate reproduction of the original program sound—than other broadcasting technologies, such as AM broadcasting. Therefore, FM is used for most broadcasts of music or general audio (in the audio spectrum). FM radio stations use the very high frequency range of radio frequencies.

AM and FM modulated signals for radio. AM (amplitude modulation) and FM (frequency modulation) are types of modulation (coding). The sound of the program material, usually coming from a radio studio, is used to modulate (vary) a carrier wave of a specific frequency, then broadcast.

In AM broadcasting, the amplitude of the carrier wave is modulated to encode the original sound. In FM broadcasting, the frequency of the carrier wave is modulated to encode the sound. A radio receiver extracts the original program sound from the modulated radio signal and reproduces the sound in a loudspeaker.
Position of FM radio in the electromagnetic spectrum
A commercial 35 kW FM radio transmitter built in the late 1980s. It belongs to FM radio station KWNR in Henderson, Nevada and broadcasts at a frequency of 95.5 MHz.