Telecommunications terms starting with D

656 terms

dejitterizer A device that reduces jitter in a digital signal. Note 1: A dejitterizer usually consists of an elastic buffer in which the signal is temporarily stored…
Delay A device used to obtain detonation of charges at separate times. An electric blasting cap which explodes at a set interval after current is passed through…
delay distortion In a waveform consisting of two or more wave components at different frequencies, distortion caused by the difference in arrival times of the frequency…
delay encoding The encoding of binary data to form a two-level signal such that (a) a "0" causes no change of signal level unless it is followed by another "0" in which…
delay equalizer A corrective network designed to make the phase delay or envelope delay of a circuit or system substantially constant over a desired frequency range.
delay line A transmission line, or equivalent device, used to delay a signal. 2. A single-input-channel device, such as a single-input sequential logic element, in…
delay modulation See delay encoding.
delay time Synonym delay.
delay working In telephone switchboard operations, operation intended to ensure fair distribution of the time of one or more lines among groups of call originators.
delayed-delivery facility In a communications network, a facility that stores data, destined for delivery to one or more addresses, for delivery at a later time.
delegated accrediting authority Synonym designated approving authority.
deleted bit A bit not delivered to the intended destination.
deleted block A block not delivered to the intended destination.
delimiter A "character" or "string" that sets bounds to an arbitrarily-sized textual object, not to be confused with a "separator" or "terminator".
Deliverable An item produced or used during development of a system that is required to be made available to the evaluators for evaluation purposes.
delivered block A successfully transferred block.
delivered duplicated frame A frame D received by a particular destination user when both of the following conditions are true: D was not generated by the source user; D is exactly…
delivered errored frame A delivered frame when the value of one or more bits in the frame is in error, or when some, but not all, bits in the frame are lost bits or extra bits (i.
delivered out-of-sequence frame A delivered frame, Fi, that arrives at the destination user after any of the frames F(i+1), F(i+2), . . .
delivered overhead bit A bit that (a) is successfully transferred to a destination user, (b) performs its primary function within the telecommunications system, and (c) does not…
delivered overhead block A block that (a) is successfully transferred to a destination user, (b) performs its primary function within the telecommunications system, and (c) does…
Delivery The amount of water delivered to the point of use. The difference between delivery and release is usually the same as consumptive use.
delivery confirmation Information returned to the originator indicating that a given unit of information has been delivered to the intended addressee(s).
Dellinger effect An effect--lasting from several minutes to several hours--that causes electromagnetic sky wave signals to disappear rapidly as a result of greatly…
Dellinger fadeout Synonym Dellinger effect.
Dellinger fading Synonym Dellinger effect.
delta frame In digital television technology, a video frame created from the preceding key frame by modifying only those pixels that have changed.
delta modulation (DM) Analog-to-digital signal conversion in which (a) the analog signal is approximated with a series of segments, (b) each segment of the approximated signal…
delta-sigma modulation Delta modulation in which the integral of the input signal is encoded rather than the signal itself.
demagnetizing Synonym degaussing.
demand assignment An operation in which several users share access to a communications channel on a real-time basis, i.e.
demand assignment multiple access (DAMA) In a communications system, a technique for allocating use of bandwidth among multiple users, based on demand.
demand factor The ratio of (a) the maximum real power consumed by a system to (b) the maximum real power that would be consumed if the entire load connected to the…
demand load In general, the total power required by a facility. Note: The demand load is the sum of the operational load (including any tactical load) and…
demand service In ISDN applications, a telecommunications service that establishes an immediate communication path in response to a user request made through…
demarc Acronym for demarcation point.
demarcation point (demarc) That point at which operational control or ownership of communications facilities changes from one organizational entity to another.
democratically synchronized network A mutually synchronized network in which all clocks in the network are of equal status and exert equal amounts of control on the others, the network…
demodulation The recovery, from a modulated carrier, of a signal having substantially the same characteristics as the original modulating signal.
demon See daemon.
demultiplex (DEMUX) See demultiplexing.
demultiplexing The separation of two or more channels previously multiplexed; i.e., the reverse of multiplexing.
deMUX Acronym for demultiplex and demultiplexer.
denial of service 1. The prevention of authorized access to resources or the delaying of time-critical operations. [2382-pt.8] 2.
dense binary code A binary code in which all possible bit patterns that can be made from a fixed number of bits are used to encode user information but no overhead…
dense wavelength division multiplexing (DWDM) Multiplexing using close spectral spacing of individual optical carriers (wavelengths) to take advantage of desirable transmission characteristics (e.g.
Density The average number of people, families, or housing units on one unit of land. Density is also expressed as dwelling units per acre.
Department of Defense (DOD) master clock See DOD master clock.
departmental security officer The person responsible to the Permanent Head of a Government Department for establishing and enforcing Departmental Security policy; this includes the…
departure angle The angle between the axis of the main lobe of an antenna pattern and the horizontal plane at the transmitting antenna. Synonym takeoff angle.
dependency In security, a relationship between requirements such that one requirement must be satisfied before others can meet their own objectives.
depolarization Reducing or randomizing the polarization of an electromagnetic wave. Note: Depolarization may be caused by transmission through a nonhomogeneous medium or…
depressed-cladding fiber Synonym doubly clad fiber.
depressed-inner-cladding fiber Synonym doubly clad fiber.
dequeue To remove items from a queue.
Deregulation The process of changing regulatory policies and laws to increase competition among suppliers of commodities and services.
derivation key A double-length key used to compute another key cryptographically. Note: The derivation key is normally used (in receiving a transaction) to derive or…
derived unique key per transaction (DUKPT) In cryptography, a key-management technique that uses a unique key for each separate transaction to prevent the disclosure of any past key used by the…
DES A synthetic form of the hormone estrogen that was prescribed to pregnant women between about 1940 and 1971 because it was thought to prevent miscarriages.
descrambler The inverse of a scrambler. Note: The descrambler output is a signal restored to the state that it had when it entered the associated scrambler, provided…
descriptive top-level specification (DTLS) A top-level specification that is written in a natural language (e.g., English), an informal program design notation, or a combination of the two [TCSEC].
Descriptor See "file descriptor".
desensitation The reduction of desired signal gain as a result of receiver reaction to an undesired signal.
design margin The additional performance capability above required standard basic system parameters that may be specified by a system designer to compensate for…
design objective (DO) In communications systems, a desired performance characteristic for communications circuits and equipment that is based on engineering analyses, but (a)…
Design, Verify and Assign (DVA) Describes a given point in the order completion process in which the circuit design is checked for accuracy and all assignments are verified/available.
designated accrediting authority Synonym designated approving authority.
designated approving authority (DAA) [The] official with the authority to formally assume responsibility for operating a system at an acceptable level of risk.
desktop publishing The use of computers and associated application software to compose, lay out, model, and develop prototypes of documents that are usually intended to be…
desktop video The application of nondedicated personal computers to the performance of video auditioning (viewing) or editing.
desktop video teleconferencing See video teleconference.
despotically synchronized network A synchronized network in which a unique master clock controls all other clocks in the network. [From Weik '89]
despun antenna In a rotating communications satellite, an antenna with a main beam that is continuously redirected with respect to the satellite so that the antenna…
destination node A node having the network address, as determined by the release node, to be where an existing call should be routed.
destination routing In communications system operations, the routing of messages based on the name of the destination office, the destination user, or the address on the…
destination routing address A list of called party numbers (primary and alternative). [T1.667-1999]
destination user In an information transfer transaction, the user that receives information from the source, i.e., from the originating user.
desynchronizer That portion of a network element (NE) that attempts to recreate a signal's original clock and attenuates the high-frequency phase variations that result…
detailed design left
Detection The first of five Early Warning System components consisting of the processes and equipment necessary to collect information about the threatening event…
detectivity The reciprocal of noise equivalent power.
Detector A passive IR, visible, UV detector turns photons into an electrical signal. The IFOV of the detector is its solid angular sub-tense.
deterministic routing In a switched network, switching in which the routes between given pairs of nodes are pre-programmed, i.e., are determined, in advance of transmission.
deterministic transfer mode An asynchronous transfer mode in which the maximum information transfer capacity of a telecommunication service is provided throughout a call.
Deutsches Institut für Normung (DIN) Germany's standards-setting organization, equivalent to the American National Standards Institute (ANSI).
Developer The person or organization that manufacturers a Target of Evaluation [ITSEC].
developer security left
development environment 1. The set of procedures, methods, tools and standards used during system development. See also: Operational Environment [CESG]. 2.
development process The set of phases and tasks whereby a Target of Evaluation is constructed, translating requirements into actual hardware and software [ITSEC].
deviation ratio In a frequency modulation system, the ratio of the maximum frequency deviation of the carrier to the maximum modulating frequency of the system under…
device certificate In cryptography, a public key certificate or an attribute certificate, issued by a device manufacturer, tying the identity of the device to its attributes.
device driver Software that enables hardware or devices (such as a printer, mouse, or keyboard) to work with your computer.
DFSK Abbreviation for double-frequency shift keying.
dHTML Abbreviation for dynamic Hypertext Markup Language. A form of HTML used to create Web-page content that, as perceived by the viewer, appears to change…
Di Group A basic group of Pulse Code Modulation (PCM) channels assembled by Time Division Multiplex. In the United States it usually consists of 24 channels at 1.
diad Synonym dibit.
diagnostic program A program used to investigate the cause or the nature of conditions or problems within specified elements of a system. 2.
dial around Pertaining to long-distance services that require consumers to dial a long-distance provider's access code (or a "10-10" number) before dialing a…
dial back Synonym call back.
dial mode Operation of data circuit-terminating equipment (DCE) so that circuitry, such as data terminal equipment (DTE), associated with call origination is…