bandwidth

(redirected from Band width)
Also found in: Dictionary, Thesaurus, Medical, Financial.
Related to Band width: Quality factor

bandwidth

1. The range of frequencies over which an instrument, such as a radio telescope, is sensitive. A wide bandwidth gives good sensitivity to sources that emit over a wide range of frequencies (e.g. by synchrotron emission), whereas a narrow bandwidth gives good sensitivity to spectral lines.
2. (coherence bandwidth) The range of frequencies over which electromagnetic or other emissions from a source maintain coherence.

bandwidth

[′band‚width]
(communications)
The difference between the frequency limits of a band containing the useful frequency components of a signal.
A measure of the amount of data that can travel a communications path in a given time, usually expressed as thousands of bits per second (kbps) or millions of bits per second (Mbps).

bandwidth

(communications)
The difference between the highest and lowest frequencies of a transmission channel (the width of its allocated band of frequencies).

The term is often used erroneously to mean data rate or capacity - the amount of data that is, or can be, sent through a given communications circuit per second.

bandwidth

(1) Computer people may use the term for capability and time. For example, "not enough bandwidth to get the job done" means not enough staff or time to do it. Its true meaning follows.

(2) The transmission capacity of an electronic pathway such as a communications line, computer bus or computer channel. Digital bandwidth is the number of pulses per second measured in bits per second (bps). For example, Ethernet transmits at different speeds, including 10 Mbps, 100 Mbps and 1000 Mbps (see Mbps and baseband).

When transmitting alternating frequencies, as with all wired analog, many wired digital and most wireless communications, the bandwidth is the difference between the highest and lowest frequencies, measured in cycles per second, or Hertz (Hz). For example, 802.11n Wi-Fi transmits in 20 MHz and 40 MHz channels within the 2.4 GHz and 5 GHz bands. The 20 and 40 MHz channel frequencies are the bandwidths, and each channel is divided into subchannels.

From Hertz to Bits - A Complicated Process
When using alternating frequencies for digital transmission, the frequencies are modified (modulated) by the digital input. Using the 802.11n Wi-Fi example, the resulting bit rate can range from 6.5 Mbps to 600 Mbps. This extremely wide range is determined by the signal strength and interference in the environment at any given moment. Any one of more than 30 combinations of channel bandwidth (20, 40 MHz), modulation scheme, error correction rate, channel spacing and number of antennas may be selected, on a packet-by-packet basis. See modulation, video bandwidth, space/time and bandwidth junkie.


Bandwidth in Hertz to Bandwidth in Bits
This quadrature PSK (QPSK) example is one of the simplest modulation schemes. Each set of two input bits modifies the carrier into four phase angles. The amplitude remains constant, unlike QAM modulation, in which the amplitude is varied (see QAM).











References in periodicals archive ?
So the new protocols and the interface standards will be developed around fiver, which can give us as much as 1,000 times the band width per dollar of copper-based networks.
Tenders are invited for Supplying and fixing of pre-programmed water quality analysis spectrometer/colorimeter auto select wave length type with minium spectral band width 10 mm operating range 0+50 degree, ac/batery operated for measuring in parameters like free chlorine fluorides, etc.
Technical features of the rotocure include: curing drum diameter of 1,200 mm (60"); upper and lower drum diameter of 1,000 mm (40"); band width of 1,500 mm (60"); welded band length of 14,300 mm; stainless steel band thickness of 1 mm; maximum drum temperature of 360 [degrees] F; maximum curing field length of 2,800 mm (110"); network pressure of 170 psi; working pressure in the steam heated platens of 142 psi; press speed from 15 to 150 m/hr.
Its distribution networks is the most advanced from the technological point of view since 49% of subscribers view the channel with a band width of 750 MHZ.
The emission monochromator shall have wavelength coverage from at least 200-900 nm and a spectral band width ranging from at least 0-30 nm 8.
Presently over 1500 Points of Presence specifically segmented for this program, a hosting center with the band width equivalent of over 2,700 T-1's, and a staffed customer service department that is available 24 hours a day are available.
Tenders are invited for Public road transport in terms of planning to kill the band width of 3 inches.
Technical features of the Rotocure include: curing drum diameter of 1,200 mm (60"); upper and lower drum diameter of 1,000 mm (40"), band width of 1,500 mm (60"); welded band length of 14,300 mm; stainless steel band thickness of 1 mm; maximum drum temperature of 360 [degrees] F; maximum curing field length of 2,800 mm (110"); network pressure of 170 psi, working pressure in the steam heated platens of 142 psi; press speed from 15 to 150 m/hr.
Usually band building machines range in band width of 48 inch to 200 inch, each size of which also has a variety of circumferential ranges which are selected by the end user.
Presently over 550 Points of Presence specifically segmented for this program, a hosting center with the band width equivalent of over 2,700 T-1's, and a staffed customer service department that is available 24 hours a day are available.
Limited Tenders are invited for 20 Mbps (1:1) Internet Band Width
Fewer cycles are required to achieve the desired amplitude tolerance level as the tolerance band width is increased.