The transmitter convertsdirect current (DC) intoalternating current (AC) at the desired frequency. Most transmitters use aquartz crystal to set the frequency of the resulting carrier wave. Amodulator modifies the carrier wave, byfrequency modulation oramplitude modulation or some other kind, to include the information needed, such as an audio or video signal. The modified waves are sent by an antenna to another antenna at the receiver which extracts the information from the waves.
