GPSAn acronym for Global Positioning System. A network of satellites which provide extremely accurate position and time information.
Graceful DegradationA condition in which a system continues to operate, providing service in a degraded mode rather than failing completely or catastrophically.
grade of service (GOS)1. The probability of a call's being blocked or delayed more than a specified interval, expressed as a decimal fraction.
graded-index fiberAn optical fiber with a core having a refractive index that decreases with increasing radial distance from the fiber axis.
graded-index profileIn the core of an optical fiber, a plot of the variation of refractive index such that the refractive index decreases with increasing radial distance from…
GradientGeneral slope or rate of change in vertical elevation per unit of horizontal distance of water surface of a flowing stream.
grandfathered systemsSystems, including but not limited to: (a) PBX and key telephone systems, directly connected to the public switched telephone network on June 1, 1978…
grandfathered terminal equipmentTerminal equipment (other than PBX and key telephone systems) and protective circuitry connected to the public switched telephone network before July 1…
GranularityThe size of the pieces you're dealing with, mentally speaking.
graphic characterA visual representation of a character, other than a control character. 2. In the ASCII code, a character other than an alphanumeric character, intended…
graphicsThe art or science of conveying information through the use of display media, such as graphs, letters, lines, drawings, and pictures.
graphics pipeIn computer science and technology, the special hardware within the computer optimized for the display of real-time 3D graphics.
Gray codeA binary code in which consecutive decimal numbers are represented by binary expressions that differ in the state of one, and only one, one bit.
Gray ScaleThe use of many shades of gray to represent an image. Continuous-tone images, such as black-and-white photographs, use an almost unlimited number of…
great circleA circle defined by the intersection of the surface of the Earth and any plane that passes through the center of the Earth.
Greenwich Civil Time (GCT)Synonym Greenwich Mean Time (GMT). Obsolete term. See Coordinated Universal Time.
Greenwich Mean Time (GMT)(GMT)Same as Coordinated Universal Time (UTC); the international time standard kept at Greenwich, England.
GroundA device used to protect the user of any electrical system or appliance from shock.
ground constantsThe electrical parameters of earth, such as conductivity, permittivity, and magnetic permeability.
ground currentIn the presence of an electrical fault, the current that flows in the protective ground wire of a power distribution system.
Ground LoopIn geothermal heat pump systems, a series of fluid-filled plastic pipes buried in the shallow ground, or placed in a body of water, near a building.
ground planeAn electrically conductive surface that serves as the near-field reflection point for an antenna. Note: A ground plane may consist of a natural (e.g.
ground potentialThe zero reference level used to apply and measure voltages in a system. Note: A potential difference may exist between this reference level and the…
ground startA method of signaling from a terminal or subscriber loop to a switch, in which method one side of a cable pair is temporarily grounded.
ground waveIn radio transmission, a surface wave that propagates close to the surface of the Earth.
ground windowThe interface or transition point between the isolated and integrated ground planes.
ground-return circuitA circuit using a common return path that is at ground potential. Note: Earth may serve as a portion of the ground-return circuit. 2.
ground-start signalingA type of analog voicegrade access line signaling that requires the customer interface (CI) to provide a ground on the ring conductor at the network…
group(also referred to as a Technology Center or TC) - a unit of several Group Art Units in the mechanical, electrical, chemical or design area, managed by one…
group addressIn a communications network, a predefined address used to address only a specified set of users. Synonym collective address.
group alerting and dispatching systemA service feature that (a) enables a controlling telephone to place a call to a specified number of telephones simultaneously, (b) enables the call to be…
group delayThe rate of change of the total phase shift with respect to angular frequency, dθ/d, through a device or transmission medium, where θ is the total phase…
group delay timeIn a group of waves that have slightly different individual frequencies, the time required for any defined point on the envelope (i.e.
group distribution frame (GDF)In frequency-division multiplexing, a distribution frame that provides terminating and interconnecting facilities at the group level, i.e.
group index (N)In fiber optics, for a given mode propagating in a medium of refractive index η, the velocity of light in vacuum, c, divided by the group velocity of the…
GSM (Global system for mobile communication)one of the leading digital cellular systems. GSM uses narrowband TDMA , which allows eight simultaneous calls on the same radio frequency.
guardIn computer security, a functional unit that provides a security filter between two data processing systems operating at different security levels or…
guard bandSee frequency guard band, time guard band.
guarded frequencyA transmission frequency that is not to be jammed or interfered with because of the value of the information being derived from it.
guided rayIn an optical fiber, a ray that is confined primarily to the core. Note: A guided ray satisfies the relation given by #f21 where θr is the angle the ray…
guided waveA wave having (a) energy concentrated near a boundary, or between substantially parallel boundaries, separating materials of different properties and (b)…
H-bendA smooth change in the direction of the axis of a waveguide, throughout which the axis remains in a plane parallel to the direction of magnetic H-field…
H-channelIn Integrated Services Digital Networks (ISDN), a 384-kb/s, 1472-kb/s, or 1536-kb/s channel, designated as "H0", "H10", and "H11", respectively…
HA1-receiver weightingA noise weighting used in a noise measuring set to measure noise across the HA1-receiver of a 302-type or similar instrument.
hack1. To break into or use a computer network or use a system without authorization, as a hacker might do. 2.
HackerSomeone who breaks into computer systems in order to steal, change or destroy information.
Hagelbarger codeA convolutional code that enables error bursts to be corrected provided that there are relatively long error-free intervals between the error bursts.
half-duplex (HDX) operationOperation in which communication between two terminals occurs in either direction, but in only one direction at a time.
halftone characteristicIn facsimile systems, the relationship between the density of the recorded copy and the density of the object, i.e., the original. 2.
Hamming codeAn error-detecting and error-correcting binary code, used in data transmission, that can (a) detect all single- and double-bit errors and (b) correct all…
Hamming DistanceThe number of non-corresponding digits in a string of binary digits; used to measure dissimilarity.
Hamming weightThe number of non-zero symbols in a symbol sequence. Note: For binary signaling, Hamming weight is the number of "1" bits in the binary sequence.
handoffThis occurs when information on positions, velocities and tracks are given by one sensor or system to another and the first sensor or system continues to…
HandoverThis occurs when information is passed on to another sensor or system in which the first does not continue to track.
handshakingIn data communications, a sequence of events governed by hardware or software, requiring mutual agreement of the state of the operational modes prior to…
handshaking procedures[The] dialogue between two information systems for synchronizing, identifying, and authenticating themselves to one another. [INFOSEC-99]
hang-upCalling- or called-user placement of a telephone set or other unit of telecommunications equipment in the quiescent state. [T1.104-1988]
hang-up signalAn on-hook signal sent from an end office toward the disconnect-control office indicating either calling or called user hang-up and requesting the…
hardenedPertaining to the condition of a facility with protective features that enable it to withstand destructive forces, such as explosions, natural disasters…
hardwareThe physical components of a computer system-the computer, plotters, printers, terminals, digitizers, and so on.
harmful interferenceAny emission, radiation, or induction interference that endangers the functioning or seriously degrades, obstructs, or repeatedly interrupts a…
harmonicOf a sinusoidal wave, an integral multiple of the frequency of the wave. Note: The frequency of the sine wave is called the fundamental frequency or the…
harmonic distortionIn the output signal of a device, distortion caused by the presence of frequencies that are not present in the input signal.
HarmonizationThe proposed harmonizing of patent laws in different countries to produce essentially one, worldwide patent law.
Hash FunctionA function used to create a hash value from binary input. The hash is substantially smaller than the text itself, and is generated by the hash function in…
hash totalThe result obtained by subjecting a set of data to an algorithm for purposes of checking the data at the time the algorithm is applied or for use at a…
hash valueIn cryptography, the result of applying a cryptologic hash function to a message. [After X9.31]
HashingThe process of using a mathematical algorithm against data to produce a numeric value that is representative of that data.