ABSTRACT
As noted in §4.1, a radio signal consists of a radio-frequency sinusoid (sine or cosine wave), called a carrier wave, that has undergone amplitude or frequency modulation. In AM the carrier amplitude is varied by the modulating signal, while in FM the carrier frequency is varied by the modulating signal. A bandwidth of as little as 5 kHz provides acceptable audible quality in an AM radio, and that of at least 10 kHz is required when the modulating signal broadcasts commercial music, whereas the range required for high-fidelity music must be wider in the range from 30 Hz (for a large organ pipe) to 15 kHz (for cymbals and trombone sounds).
