Method of adding an audio signal to a carrier radio frequency (modulating the signal) so that the audio signal can be transmitted from place to place and later decoded from the radio frequency for reproduction. The basic theory of frequency modulation is to take a very high frequency signal (a radio frequency) and map onto it a much lower frequency signal (the audio signal). n audio signal’s frequency band is from 20 Hz to 20 kHz (20,000 Hz). Radio frequencies used to broadcast FM radio signals range from around 88 MHz to 108 MHz (88,000,000 Hz to 108,000,000 Hz). Obviously, there is a vast difference in frequency between the two. Additionally, audio waves and electromagnetic waves (such as radio waves and light waves) operate in two different media with sound waves travelling through air, water or other physical substances. Electromagnetic waves do not need such substances and instead travel as magnetic waves through air, water, or anything else including the lack of substance in space. he relatively small 20 Hz to 20 kHz spread of audio frequencies can be placed on top of the radio frequency. For instance, if the sound spectrum were placed on a radio frequency of 100 MHz, it would only move above and below the 100 MHz level to 100.02 MHz and 99.98 MHz. adio frequency waves travel easily through the atmosphere over long distances (and can actually travel out into space indefinitely), while audio waves cannot (for instance, someone yelling from across a field is difficult or impossible to hear). By combining the audio frequency with the carrier signal in the radio frequency spectrum, the audio frequency can be transmitted over long distances. The combination essentially blends the audio signal with the very high frequency of the radio frequency. High-power antennas broadcast this signal, and smaller antennas connected to tuning devices pick up the signal. uners allow users to choose a particular carrier frequency. The tuner then strips out the carrier frequency to leave only the audio frequency. The audio frequency is then played over a sound system like any other audio signal.