black burstA composite color video signal comprised of sync, color burst, and black video.
black facsimile transmissionIn facsimile systems using amplitude modulation, that form of transmission in which the maximum transmitted power corresponds to the maximum density of…
black levelOf a television baseband signal (e.g., NTSC composite video), the voltage level corresponding to black or to the maximum limit of black peaks.
black noiseNoise that has a frequency spectrum of predominately zero power level over all frequencies except for a few narrow bands or spikes.
black recording1. In facsimile systems using amplitude modulation, recording in which the maximum received power corresponds to the maximum density of the record medium.
BLACK signalA signal that represents only unclassified or encrypted information, usually in cryptographic systems.
BlackbodyAn ideal substance that absorbs all radiation falling on it, and reflecting nothing.
blanketingThe interference that is caused by the presence of an AM broadcast signal of one volt per meter (V/m) or greater strengths in the area adjacent to the…
blanketing areaIn the vicinity of a transmitting antenna, the area in which the signal from that antenna interferes with the reception of other signals.
blankingThe period of time in which no video image is displayed. [JP 1-02] 2. In graphic display, the suppression of the display of one or more display elements…
blanking intervalIn raster-scanned television technology, the period between (a) the end of one horizontal scanning line and the beginning of the next (the horizontal…
blanking levelIn a baseband television signal, the DC level (nominally 0 volts) from which the amplitudes of the various components of the signal are measured.
blind transmissionTransmission without obtaining a receipt, i.e., acknowledgement of reception, from the intended receiving station.
blinkingIn graphic display devices, an intentional periodic change in the intensity of one or more display elements or display segments.
blockA repetition/replication of the Early, Mid and Late Seral Treatment plots and a Control plot. See Repetition/replication.
block checkIn the processing or transmission of digital data, an error-control procedure that is used to determine whether a block of data is structured according to…
Block Check Character (BCC)The result of a transmission verification algorithm accumulated over a transmission block, and normally appended at the end, e.g., CRC, LRC.
block codeAn error detection and/or correction code in which the encoded block consists of N symbols, containing K information symbols (K<N) and N-K redundant check…
block diagramA diagram of a system, a computer, or a device in which the principal parts are represented by suitably annotated geometrical figures to show both the…
block distortionIn the received image in video systems, distortion characterized by the appearance of an underlying block encoding structure.
block droppingA process by which one or more of the less significant bits of all the samples stored in a packet are dropped to alleviate congestion. [T1.509-1995]
block efficiencyIn a block, the ratio of the number of user information bits to the total number of bits.
block errorA block within which at least one bit error occurs when the block is transferred from the source to the destination within the time slot assigned.
Block HolderThe Service Provider to which a thousands-block (NXX-X) has been assigned for use.
block lengthThe number of data units, such as bits, bytes, characters, or records, in a block.
block parityThe designation of one or more bits in a block as parity bits used to force the block into a selected parity, either odd or even.
block transferThe process, initiated by a single action, of transferring one or more blocks of data.
block transfer attemptA coordinated sequence of user and telecommunication system activities undertaken to effect transfer of an individual block from a source user to a…
block transfer efficiencyThe average ratio of user information bits to total bits in successfully transferred blocks.
block transfer failureFailure to deliver a block successfully. Note: The principal block transfer failure outcomes are: lost block, misdelivered block, and added block.
block transfer rateThe number of successful block transfers during a performance measurement period divided by the duration of the period.
block transfer timeThe average value of the duration of a successful block transfer attempt. Note: A block transfer attempt is successful if (a) the transmitted block is…
block-error ratioThe ratio of the number of incorrectly received blocks to the total number of blocks transferred.
block-loss probabilityThe ratio of the number of lost blocks to the total number of block transfer attempts during a specified period.
block-misdelivery probabilityThe ratio of the number of misdelivered blocks to the total number of block transfer attempts during a specified period.
Blocked CallA blocked call is said to have occurred when a call presented to a telecommunications Service Provider (SP) facility cannot be completed due to Blocking.
BlockingThe sticking together or adhesion of successive windings in a tape pack. Blocking can result from (1) deterioration of the binder, (2) storage of tape…
blocking criterionIn telephone traffic engineering, a criterion that specifies the maximum number of calls or service demands that fail to receive immediate service.
blocking factorIn a tape backup operation, the number of tape blocks that are transferred in each write operation.
blocking formulaA specific probability distribution function intended to model calling patterns of users who fail to find available facilities.
blocking networkIn telecommunications, a network that has fewer transmission paths than would be required if all users were to communicate simultaneously.
blue noiseIn a spectrum of frequencies, a region in which the spectral density, i.e., power per hertz, is proportional to the frequency.
BluetoothA low-power, short-range, rf technology that allows the connection of intelligent communications devices or appliances in a household or an office in a…
blurringIn television and video systems, a global distortion over the entire image, characterized by reduced sharpness of edges and limited spatial detail. [T1.
BNC connectorA type of bayonet (twist-lock) coaxial connector commonly used in applications involving small (e.g., RG-59, RG-62) coaxial cables.
Boltzmann's constant (k)The number that relates the average energy of a molecule to its absolute temperature. Note: Boltzmann's constant is approximately 1.
BondA long-term debt instrument with the promise to pay a specified amount of interest and to return the principal amount on a specified maturity date.
bondingIn electrical engineering, the process of connecting together metal parts so that they make low resistance electrical contact for direct current and lower…
bookmarkA link to a Web site or page previously visited.
Boolean functionA mathematical function that describes Boolean operations. 2. A switching function in which the number of possible values of the function and each of its…
Boolean operationAny operation in which each of the operands and the result take one of two values.
boot upTo take some kind of assenting action to initiate computer bootup, e.g., to turn on the primary power (often referred to as initiating a cold bootup) or…
bootstrapA technique or device designed to bring about a desired state by means of its own action. 2.
bootupIn computer science, the initial sequence of events (usually preprogrammed in firmware present in the computer) that are necessary to start a computer; i.
boresight1. The physical axis of a directional antenna. 2. To align a directional antenna, using either an optical procedure or a fixed target at a known location.
BotRobot. Software automaton, used to play and advance a character without human assistance or supervision.
bounceTo return, to the sender, e-mail that is, for whatever reason, undeliverable to its intended destination.
bouncing busy hour (BBH)The hour in which the highest usage is measured for any day. The readings are on the hour or half hour.
bound modeIn an optical fiber, a mode that (a) has a field intensity that decays monotonically in the transverse direction everywhere external to the core and (b)…
braidAn essential part of many fiber-optic cable designs, consisting of a layer of woven yarn.
BranchAn addition to the main pipe in a piping system.
branch pointA network point where two or more possible routes through different intermediate networks from the origination network to destination network physically…
branching networkA network used for transmission or reception of signals over two or more channels.
Breach1. The breaking or violating of a law, right or duty, either by an act or omission. 2. The failure to carry out any condition of a contract.
breadboardAn assembly of circuits or parts used to prove the feasibility of a device, circuit, system, or principle with little or no regard to the final…
break intervalIn dial-pulse signaling, that portion of the dial pulse in which the pulsing circuit is in its high-impedance condition. [T1.405-1989] 2.
break outTo separate the individual fibers or buffer tubes of a fiber-optic cable for the purpose of splicing or installing optical connectors.
break-out boxA testing device that permits a user to access individual leads of an interface cable, using jumper wires, in order to monitor, switch, or patch the…
breakout cableA multifiber fiber-optic cable design in which individual fibers, usually tight-buffered, are surrounded by separate strength members and jackets, which…
breakout kitA kit of materials, composed of an outer jacket in which is contained a strength member consisting of a bundle of usually aramid yarn, which jacket and…
Brewster's angleFor a plane electromagnetic wavefront incident on a plane boundary between two dielectric media having different refractive indices, the angle of…
brickAn informal name for a hand-held radiotelephone unit. Synonyms personal terminal, radio personal terminal.
brick wall filterA low-pass filter with a steep cut-off (such as 20 dB/octave or greater), such that a negligible amount of higher frequency information passes.
bridgeA filter paper or other substrate used as a wick and support structure for a plant tissue in culture when a liquid medium is used.
bridge lifterA device that electrically or physically removes bridged telephone pairs. Note: Relays, saturable inductors, and semiconductors are used as bridge lifters.
bridge-to-bridge stationA ship station operating in the port operations service in which messages are restricted to navigational communications and which is capable of operation…
bridged ringingThe part of a signaling system in which ringers associated with a particular line are connected across that line.
bridged tapAny portion of a loop that is not in the direct talking path between the central office and the service user's terminating equipment.
bridging connectionA parallel connection used to extract some of the signal energy from a circuit, usually with negligible effect on the normal operation of the circuit.
bridging lossAt a given frequency, the loss that results when an impedance is connected across a transmission line.
BrightnessA basic visual sensation describing the amount of light that appears to emanate from an object, or more precisely, the luminance of an object