# Modulation of AM and FM radio

* The amplitude and wavelength were arbitrarily adjusted to see it easily.
* For your understanding, the frequency modulation range of FM broadcasts is exaggerated.

The audible frequency, commonly referred to as 'sound', is in the frequency range of about 20 Hz to 20 kHz.
In order to transmit and receive electromagnetic waves of this audible frequency directly to the radio, there are a number of restrictions, such as the size of the antenna must be huge.
In general, electromagnetic waves for broadcast have much higher frequency.
Frequently used AM and FM radio frequency bands are as follows.