<P> Baseband is a signal that has a very narrow and near - zero frequency range, i.e. a spectral magnitude that is nonzero only for frequencies in the vicinity of the origin (termed f = 0) and negligible elsewhere . In telecommunications and signal processing, baseband signals are transmitted without modulation, that is, without any shift in the range of frequencies of the signal . Baseband has a low - frequency--contained within the bandwidth frequency close to 0 hertz up to a higher cut - off frequency . Baseband can be synonymous with lowpass or non-modulated, and is differentiated from passband, bandpass, carrier - modulated, intermediate frequency, or radio frequency (RF). </P> <P> A baseband signal or lowpass signal is a signal that can include frequencies that are very near zero, by comparison with its highest frequency (for example, a sound waveform can be considered as a baseband signal, whereas a radio signal or any other modulated signal is not). </P> <P> A baseband bandwidth is equal to the highest frequency of a signal or system, or an upper bound on such frequencies, for example the upper cut - off frequency of a low - pass filter . By contrast, passband bandwidth is the difference between a highest frequency and a nonzero lowest frequency . </P> <P> A baseband channel or lowpass channel (or system, or network) is a communication channel that can transfer frequencies that are very near zero . Examples are serial cables and local area networks (LANs), as opposed to passband channels such as radio frequency channels and passband filtered wires of the analog telephone network . Frequency division multiplexing (FDM) allows an analog telephone wire to carry a baseband telephone call, concurrently as one or several carrier - modulated telephone calls . </P>

Difference between low pass channel and bandpass channel