Editing Baseband (section)

{{Short description|Range of frequencies occupied by an unmodulated signal}}

[[File:bandlimited2.svg|thumb|Spectrum of a '''baseband signal''', energy ''E'' per unit frequency as a function of frequency ''f''. The total energy is the area under the curve.]]

In [[telecommunications]] and [[signal processing]], '''baseband''' is the range of frequencies occupied by a [[signal]] that has not been [[modulation|modulated]] to higher frequencies.<ref>Jeff Rutenbeck, ''Tech Terms: What Every Telecommunications and Digital Media Professional Should Know'', [https://books.google.com/books?id=dfFsAAAAQBAJ&pg=PA24 p. 24], CRC Press, 2012 {{ISBN|1136034501}}</ref> Baseband signals typically originate from [[transducer]]s, converting some other variable into an electrical signal.  For example, the electronic output of a microphone is a baseband signal that is analogous to the applied voice audio. In conventional [[analog signal|analog]] [[radio broadcasting]], the baseband [[audio signal]] is used to [[Modulation|modulate]] an [[Radio frequency|RF carrier signal]] of a much higher frequency.

A baseband signal may have frequency components going all the way down to the [[DC bias]], or at least it will have a high [[ratio bandwidth]].  A modulated baseband signal is called a [[passband signal]].  This occupies a higher range of frequencies and has a lower ratio and [[fractional bandwidth]].