What is Baseband?
Baseband is
a signal that has a 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. The baseband can be synonymous
with lowpass or non-modulate, and is differentiate
from passband, bandpass, carrier-modulate, intermediate
frequency, or radiofrequency (RF).
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.
Baseband Signal
A base-band
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 basebands signal, whereas
a radio signal or any other modulated signal is not).
A base-band 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 the highest frequency and a nonzero lowest frequency.
Baseband Channel
A basebands
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 basebands telephone call, concurrently as one or
several carrier-modulated telephone calls.
Baseband Processor
A base-band processor is also known as BP or BBP is used to process the down-converted
digital signal to retrieve essential data for the wireless digital system. The
basebands processing block in GNSS receivers is usually responsible
for providing observable data: code pseudo-ranges and carrier phase
measurements, as well as navigation data.
Digital Baseband Transmission
Digital base-band transmission, also known as line coding, aims at transferring a digital bit stream over basebands channel, typically an unfiltered wire, contrary to passband transmission, also known as carrier-modulated transmission. Passband transmission makes communication possible over a bandpass filtered channel, such as the telephone network local-loop or a band-limited wireless channel.
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