Telecommunications terms starting with F

396 terms

FM broadcast translator See translator.
FM capture effect Synonym capture effect.
FM capture ratio See capture effect.
FM improvement factor The quotient obtained by dividing the signal-to-noise ratio (SNR) at the output of an FM receiver by the carrier-to-noise ratio (CNR) at the input of the…
FM improvement threshold The point in an FM receiver at which the peaks in the rf signal equal the peaks of the thermal noise generated in the receiver.
FM threshold effect In an FM receiver, the effect produced when the desired-signal gain begins to limit the desired signal, and thus noise limiting (suppression).
FM threshold extension A change in the value of the FM threshold of a receiver. Note: FM threshold extension may be obtained by decreasing the operational bandwidth, thus…
FO Force Operations (PATRIOT).
followup Synonym thread.
Footprint The land or water area covered by a project. This includes direct physical coverage (i.e.
forbidden character Synonym illegal character.
forced rerouting A procedure of transferring signaling traffic from one signaling route to another, when the signaling route in use fails or is required to be cleared of…
foreign exchange (FX) service A network-provided service in which a telephone in a given local exchange area is connected, via a private line, to a central office in another, i.e.
foreign instrumentation signals intelligence (FISINT) Intelligence information derived from electromagnetic emissions associated with the testing and operational deployment of foreign aerospace, surface, and…
form The mass or shape of an object or objects that appears unified, such as a vegetative opening in a forest, a cliff formation, or a water tank.
formal proof A complete and convincing mathematical argument, presenting the full logical justification for each proof step, for the truth of a theorem or set of…
formal security policy model 1. A mathematically precise statement of a system security policy. Some formal modeling techniques include: state transition models, temporal logic…
formal top-level specification (FTLS) A Top-Level Specification that is written in a formal mathematical language to allow theorems showing correspondence of the system specification to its…
formal verification The process of using formal proofs to demonstrate the consistency (design verification) between a formal specification of a system and a formal security…
Format The internal structure of a file, which defines the way it is stored and used. Specific applications may define unique formats for their data (i.e.
format converter 1. In video and television technology, a device that allows the reformatting of a digital data stream originating from one sampling structure (lines per…
format structure A combination of two or more data elements grouped in a prescribed sequence. [T1.201-1987] [T1.205-1988]
FORTRAN Formula Translation Language.
fortuitous conductor Any conductor that may provide an unintended path for signals. Note: Examples of fortuitous conductors are water pipes, wires, cables, and metal building…
fortuitous distortion Distortion resulting from causes generally subject to laws concerning random occurrences.
forum A computer conference devoted to a specific subject, having an initiator, members, readers, and possibly moderators. [2382-pt.
forward busying In a telecommunications system, a feature in which supervisory signals are forwarded in advance of address signals in order to seize assets of the system…
forward channel The channel of a data circuit that transmits data from the originating user to the destination user.
forward echo In a transmission line, an echo propagating in the same direction as the original wave and consisting of energy reflected back by one discontinuity and…
forward error correction (FEC) A system of error control for data transmission wherein the receiving device has the capability to detect and correct any character or code block that…
forward indicator bit (FIB) A bit in a signal unit which indicates the start of a retransmission cycle. [T1.226-1992]
forward propagation ionospheric scatter (FPIS) Synonym ionospheric scatter.
forward recovery The data reconstitution of a later version of data by using an earlier version and data recorded in a journal. [2382-pt.8]
forward scatter The deflection--by diffraction, nonhomogeneous refraction, or nonspecular reflection by particulate matter of dimensions that are large with respect to…
forward secrecy The confidence that the compromise of a long-term private key does not compromise any earlier session keys. [After X9.42]
forward sequence number (FSN) A field in a signal unit used to identify the transmitted message signal units. [T1.226-1992]
forward signal A signal sent in the direction from the calling to the called station, i.e., from the original data source to the original data sink.
FOT Follow-On Technologies.
four-wire circuit A two-way circuit using two paths so arranged that the respective signals are transmitted in one direction only by one path and in the other direction by…
four-wire repeater A repeater, consisting of two amplifiers, one associated with each direction, used in a four-wire circuit.
four-wire terminating set A balanced transformer used to perform a conversion between 4-wire and 2-wire operation.
Fourier analysis The definition of a periodic waveform of arbitrary shape as a summation of sine waves having specific amplitudes and phases, and having frequencies…
fox message A standard test message that includes all the alphanumerics on a teletypewriter and also function characteristics (yyspace, figures shift, letters shift).
FPIS Abbreviation for forward propagation ionospheric scatter. See ionospheric scatter.
FPS Fujita-Pearson Scale
fractal A mathematical formula or algorithm that constitutes or defines an efficient way of formulating computer graphics.
fractional frequency deviation Synonym fractional frequency offset.
fractional frequency fluctuation The deviation of the frequency of an oscillator from its nominal constant frequency, normalized to the nominal frequency.
fractional frequency offset A measure of the deviation of the frequency of a signal from a reference, expressed as a ratio.
fractional T1 In telecommunications, a portion of the 1.544 Mb/s (T1-aggregate) bit stream; the available fractions being determined by the type of multiplexer used to…
Fragmentation Process by which habitats are increasingly subdivided into smaller units, resulting in their increased insularity as well as losses of total habitat area.
Frame The stationary portion of a window unit that is affixed to the facade and holds the sash or other operable portions of the windows.
frame alignment In the reception of framed digital data, the extent to which a received frame is correctly aligned with respect to the clock at the receiver. 2.
frame check sequence (FCS) See cyclic redundancy check.
frame duration The time between the beginning of a frame and the end of that frame. Note: For fixed-length frames, at a fixed data rate, frame duration is constant.
frame frequency Synonym frame rate.
frame grabber A device that can seize and record a single frame of video information out of a sequence of many frames.
frame matching The process of comparing one sequence of frames with another sequence of frames in order to determine the correspondence between frames in each sequence…
frame overhead Bits (binary digits) that are added at regular intervals to a digital signal at the sending end of a digital link and used to provide network functions…
frame pitch The distance, time, or number of bits between corresponding points, i.e., significant instants, in two consecutive frames. [From Weik '89]
frame rate The number of frames transmitted or received per unit time. Note 1: The frame rate is usually expressed in frames per second.
frame relay An interface protocol for statistically multiplexed packet-switched data communications in which (a) variable-sized packets (frames) are used that…
frame relaying protocol data unit (FPDU) A data unit exchanged at the user-network interface and having a format based on that defined in CCITT Recommendation Q.921 (1988) (ANSI T1.602). [T1.
frame relaying service data unit (FSDU) The data unit exchanged at the functional boundary between the core function of Q.
frame size The number of octets after the address field and before the frame check sequence (FCS) field in a frame.
frame slip In the reception of framed data, the loss of synchronization between a received frame and the receiver clock, causing a frame misalignment event, and…
frame synchronization Of a received stream of framed data, the process by which incoming frame alignment signals, i.e., distinctive bit sequences, are identified, i.e.
frame synchronization pattern In digital communications, a prescribed recurring pattern of bits transmitted to enable the receiver to achieve frame synchronization.
frame-alignment recovery time Synonym reframing time.
frame-alignment signal In the transmission of data frames, a distinctive sequence of bits used to accomplish frame alignment.
frame-alignment time slot A time slot occupying the same relative position in every frame and used to transmit the frame alignment signal. [T1.107-1988]
frame-rate conversion With respect to television or other video display technologies, the process of transforming from one standard frame rate to another, using an algorithm.
framed interface An interface through which information flow is partitioned into physical, periodic frames consisting of overhead information and an information payload.
Framing The structural materials and elements used to construct a wall.
framing bit A bit used for frame synchronization. 2. In a bit stream, a bit used in determining the beginning or end of a frame.
framing signal See frame-alignment signal, framing bit.
Fraunhofer diffraction pattern Synonym far-field diffraction pattern.
Fraunhofer region Synonym far-field region.
free net A radio net in which any station may communicate with any other station in the net without first obtaining the permission of the net-control station.
free routing The routing of messages in such a manner that they are forwarded toward their destination or addressee over any available channel without dependence upon…
free space A theoretical concept of space devoid of all matter. Note: Free space also implies remoteness from material objects that could influence the propagation…
free-running capability In a synchronized oscillator, the capability to operate in the absence of a synchronizing signal.
free-space coupling Coupling of magnetic, electric, or electromagnetic fields that are not confined to a conductor.
free-space loss The signal attenuation that would result if all absorbing, diffracting, obstructing, refracting, scattering, and reflecting influences were sufficiently…
freenet A system of computer networks (usually funded by individuals or organizations) consisting of community-based bulletin board systems with, e.g.
freeware Historically, any software that you give away, particularly if you make the source code available as well. Now often called open source software.
freeze frame A frame of visual information that is selected from a set of motion video frames, and is held in a buffer.
freeze frame television Television in which fixed ("still") images are transmitted sequentially at a rate far too slow to be perceived as continuous motion by human vision.
freeze-out The condition that occurs when an earlier nonactive speaker on an input transmission trunk channel becomes active and cannot immediately be assigned to a…
freeze-out fraction The ratio of the total time that the individual channels experience the freeze-out condition to the total time of the active intervals, and their…
Frequency The number of cycles through which an alternating current passes per second; in the U.S.
frequency accuracy The degree of conformity to a specified value of a frequency.
frequency aging Of an oscillator, the change in frequency, over time, caused by internal changes in oscillator parameters even when external factors, such as environment…
frequency allocation See allocation (of a frequency band).
frequency allotment See allotment (of a radio frequency or radio frequency channel).
frequency assignment Authorization, given by an Administration, for a radio station to use a radio frequency or radio frequency channel under specified conditions 2.
frequency assignment authority The power granted an Administration, or its designated or delegated leader or agency via treaty or law, to specify frequencies, or frequency bands, in the…
frequency averaging The process by which the relative phases of precision clocks are compared for the purpose of defining a single time standard. 2.
frequency band See electromagnetic spectrum.
frequency band allocation See allocation (of a frequency band).