Balanced - Signaling code with an equal number of high and low states.
Bandpass - A range of wavelengths over which a component will meet specifications.
Bandwidth - The information capacity of a fiber optic cable. Precisely it is usually measured in GHz (1 Billion Hz). Occasionally it is idiomatically discussed in terms of the data transmission rate- the BPS- the actual GHz bandwidth can support. In some contexts it is expressed as MHz-km and denotes the analog bandwidth capability of digital transitions per second that a fiber optic cable can sustain over a 1-km distance. Occasionally the bandwidth of a light source is referred to. This is the width of the spectrum emitted.
Bandwidth-limited operation - The condition in a fiber optic cable based communications link when bandwidth, rather than received signal power, limits performance. This condition is reached when the signal becomes distorted, principally by dispersion, beyond specified limits.
Baseband - A method of communication in which a signal is transmitted at its original frequency rather than being impressed upon a carrier frequency.
Baud - A unit of data transmission signaling speed - data transmission rate - equal to the number of signal symbols per second. With binary modulation systems this is the same as the data transmission rate in Bits Per Second. However, it is different with non-binary modulation systems.
Beam splitter - An optical device, such as a partially reflecting mirror, for dividing an optical beam in 2 or more separate beams. It can be used in a fiber optic cable data link as a directional coupler.
Bend loss - A+ form of increased attenuation caused by allowing high order modes to radiate from the walls of a fiber optic cable. There are 2 common types of bend losses. The first type results when the fiber optic cable is curved through a restrictive radius or curvature. The second type is generally referred to as microbends. It is caused by small distortions of the fiber optic cable imposed by externally induced perturbations as, for example, slip shod cabling techniques.
BER - Bit Error Rate. This is the probability that a transmitted bit is demodulated in error at the destination receiver.
Biconic - A connector type which has a taper sleeve which would be fixed to the fiber optic cable. When this plug was inserted into its receptacle the tapered end was a means for locating the fiber optic cable in the proper position. With this connector cap, fit over the ferrules, rest against guided rings and screw onto the threaded sleeve to secure the connection. This was one of the earliest connectors used in fiber optic systems but is in little use at present.
Bit - A binary digit which is generally either '0' or '1.' It is the smallest representation of information in a communications and/or computing system.
Bit rate - The number of bits of data transmitted per second over a communications link. This usually represented as BPS with KBPS standing for kilo bits per second (1000 BPS) and MBPS standing for mega bits per second (million BPS) and GBPS standing for giga bits per second (billion BPS) etc.
Break Out cable - Same as a Fan Out cable. This is a multiple fiber optic cables constructed in the tight buffered design. It is designed for ease of connectorization and rugged applications for intra-building and inter-building requirements.
Broadband - A method of communication in which the signal is transmitted by being impressed on a higher frequency carrier. Also the ability of a communications system to carry a multitude of signals simultaneously. In data transmission is denotes transmission facilities capable of handling frequencies greater than those for high-grade voice communications. The higher frequency allows the carrying of several simultaneous channels. Broadband infers the use of a carrier signal rather than direct modulation, baseband.
Buffer - A protective layer over the fiber optic cable, such as a coating, an inner jacket, or a hard tube. The primary buffer, next to the cladding, is 250 mm in diameter. A secondary buffer of 900 mm is used on indoor cables.
Buffer coating - A protective layer, such as an acrylic polymer, applied over the fiber optic cable cladding.
Buffered fiber - Fiber optic cable protected with an additional material, usually hytrel or nylon, to provide ease in handling, connectorization and increased tensile strength.
Buffering - It is used in 2 contexts. First, it refers to a protective material extruded directly on the fiber optic cable coating to protect it from the environment. Secondly, it refers to extruding a tube around the coated fiber optic cable to allow isolation of the fiber from stresses.
Buffer tube - A hard plastic tube, having an inside diameter several times that of a fiber optic cable, that holds 1 or more fiber optic cables.
Building entrance - Terminal cable entrance point where typically a trunk cable between buildings is terminated and fiber is then distributed through the building.
Bundle - Many individual fiber optic cables within a single jacket or buffer tube. Also, a group of buffered fiber optic cables distinguished in some fashion from another group in the same cable core.
Bus network - A network topology in which all of the terminals are attached to a transmission medium serving as a bus. All other terminals receive all signals transmitted from a terminal connected to the bus.
Bus - Commonly called data bus. The term is used to describe the physical linkage between stations on a network sharing a common communication.
Byte - A unit of 8 bits.
No comments:
Post a Comment