What does sideband mean?
A sideband is a range of frequencies lying immediately above or below the main carrier or signal band in a communications system. It can carry additional information and is commonly encountered in radio transmission, modulation, filtering, and signal analysis. Depending on the design, a system may transmit one sideband, suppress one sideband, or use both. The term is technical rather than general, but it is useful for understanding how information can be represented outside a principal frequency band. Its compound structure is also intuitive: a sideband is, in effect, a band running alongside another band. The phrase “upper sideband” identifies the band above the carrier frequency, while “lower sideband” identifies the band below it.
nounA band of radio frequencies adjacent to and outside the principal or carrier frequency band, often used to transmit additional information. In signal processing, it may also refer to a band adjacent to a signal's main passband.
- A band of radio frequencies immediately above or below a carrier frequency or principal signal band.
- A frequency band adjacent to the passband of a filter or other signal-processing system.
"The radio receiver filtered out the unwanted lower sideband."
"Analysts examined both sidebands to identify interference in the transmission."
"The device attenuates the lower sideband while preserving the desired signal."
Commonly used in the plural when referring to the frequency bands above and below a carrier or signal band.
"The two sidebands carry redundant versions of the transmitted signal."
A sideband carries information beyond the main signal band—an apt name for extra material traveling alongside the central frequency.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of sideband
The compound combines “side,” from Old English, with “band,” borrowed through Old French from an Italian term referring to a strip or band. The technical use of “sideband” developed with radio and signal-processing systems, when engineers described frequency bands adjacent to a carrier frequency.
Related word forms
How sideband is actually used
Primarily used in radio, telecommunications, and signal-processing contexts. Upper and lower sidebands are distinguished by their position relative to the carrier frequency.