Monday, 30 November 2020

Baseband

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).


Baseband Signal

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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