Text: Modulation, in a broad sense, is the process of altering an electrical signal so that is carries some sort of information - music, speech, dots and dashes, etc.. In audio, the intensity of an otherwise steady electric current is varied in accordance with the sound wave patterns of the program. In radio, modulation refers to superimposing an audio signal on the radio frequency wave (the "carrier wave"). At the radio receiver, a circuit known as a detector then separates the audio signal from the carrier. Once the audio signal is recovered, it is amplified and fed to the speakers for reproduction of the original sound wave pattern.

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