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Unformatted text preview: In AM (amplitude modulation) radio transmissions, the amplitude of the combined audio frequency and radio frequency waves varies to match the audio signal. AM radio is subject to problems with static interference. Electromagnetic waves (like radio waves) are produced by the spark discharges in car ignition systems, brushes of electric motors and in all sorts of electrical appliances, as well as in thunderstorms. There is considerable background noise that changes the amplitude of the radio wave signal adding random crackling noises called static. In FM (frequency modulation) radio transmissions, the frequency of the combined waves changes to reproduce the audio signal. For example, higher frequency is associated with the peak amplitude in the audio wave. FM waves do not have a problem with interference because the noise background does not modify the radio wave frequency. In addition FM waves give better sound reproduction....
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- Spring '09