sideband

In radio communications, a sideband is a band of frequencies higher than or lower than the carrier frequency, containing power as a result of the modulation process. The sidebands consist of all the Fourier components of the modulated signal except the carrier. All forms of modulation produce sidebands.
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In amplitude modulation (AM), a band of frequencies higher than or lower than the carrier frequency , containing energy as a result of the modulation process. (188 ) Note: Amplitude modulation results in two sidebands. The frequencies above the carrier frequency constitute what is referred to as the "upper sideband" those below the carrier frequency, constitute the "lower sideband." In conventional AM transmission , both sidebands are present. Transmission in which one sideband is removed is called "single-sideband transmission ."