Telecommunications — page 33 of 85

8,405 terms including subtopics (8,400 terms filed directly here)

Subtopics

Mobile 5 terms

Telecommunications terms

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).
frequency coherence See phase coherence.
frequency compatibility 1. Of an electronic device, the extent to which it will operate at its designed performance level in its intended operational environment (including the…
frequency departure The difference between the instantaneous frequency of a digital signal and the long-term average frequency of that signal. [T1.Rpt17-1993] 2.
frequency deviation The amount by which a frequency differs from a prescribed value, such as the amount an oscillator frequency drifts from its nominal frequency. 2.
frequency dispersal An electronic counter-countermeasure (ECCM) in which communications nets' operating frequencies are widely separated from each other, causing a…
frequency displacement The end-to-end shift in frequency that may result from independent frequency translation errors in a circuit.
frequency distortion Synonym amplitude-vs.-frequency distortion.
frequency diversity Transmission and reception in which the same information signal is transmitted and received simultaneously on two or more independently fading carrier…
frequency drift An undesired progressive change in frequency with time. Note 1: Causes of frequency drift include component aging and environmental changes.
frequency fluctuation A short-term variation, with respect to time, of the frequency of an oscillator.
frequency flutter A deviation of frequency that generally results from irregular motion of the recording medium during the recording, duplication, or reproduction. [T1.
frequency frogging The interchanging of the frequencies of carrier channels to accomplish specific purposes, such as to prevent feedback and oscillation, to reduce…
frequency guard band A frequency band deliberately left vacant between two channels to provide a margin of safety against mutual interference.
frequency hopping [The] repeated switching of frequencies during radio transmission according to a specified algorithm, to minimize unauthorized interception or jamming of…
frequency hour One frequency used for one hour regardless of the number of transmitters over which it is simultaneously broadcast by a station during that hour. [47CFR]
frequency instability See frequency stability.
frequency lock The condition in which a frequency-correcting feedback loop maintains control of an oscillator within the limits of one cycle.
Frequency Modulation (FM) Modulation in which the instantaneous frequency of a sine wave carrier is caused to depart from the center frequency by an amount proportional to the…
frequency of optimum traffic (FOT) Synonym FOT.
frequency of optimum transmission (FOT) See FOT.
frequency offset The difference between the frequency of a source and a reference frequency.
frequency prediction A prediction of the maximum usable frequency (MUF), the optimum traffic frequency, and the lowest usable frequency (LUF) for transmission between two…
frequency range A continuous range or spectrum of frequencies that extends from one limiting frequency to another.
frequency response See insertion-loss-vs.-frequency characteristic.
frequency response curve A plot of the gain or attenuation of a device, such as an amplifier or a filter, as a function of frequency.
frequency scanning Conducting a search for signals over a band or range of frequencies by means of a manually or automatically tuned receiver. Note: The tuning rate, i.e.
frequency sharing The assignment to or use of the same radio frequency by two or more stations that are separated geographically or that use the frequency at different…
frequency shift Any change in frequency. 2. Any change in the frequency of a radio transmitter or oscillator.
frequency source See frequency standard.
frequency spectrum See electromagnetic spectrum.
frequency spectrum congestion The situation that occurs when many stations transmit simultaneously using frequencies that are close together, i.e.
frequency stability The degree to which variations of the frequency of an oscillator deviate from the mean frequency over a specified period of time.
frequency standard A stable oscillator used for frequency calibration or reference. Note 1: A frequency standard generates a fundamental frequency with a high degree of…
frequency synthesizer A device that produces frequencies that are phase coherent with a reference frequency.
frequency tolerance The maximum permissible departure by the center frequency of the frequency band occupied by an emission from the assigned frequency, or by the…
frequency translation The transfer of signals occupying a specified frequency band, such as a channel or group of channels, from one portion of the frequency spectrum to…
frequency-analysis compaction Data compaction accomplished by using an expression composed of a number of different frequencies of different magnitudes to represent a particular curve.
frequency-change signaling A signaling method in which one or more discrete frequencies correspond to each desired significant condition of a code.
frequency-derived channel A channel derived by dividing an allocated or available bandwidth over a medium into two or more portions, each usable separately.
frequency-division multiple access (FDMA) The use of frequency division to provide multiple and simultaneous transmissions to a single transponder.
frequency-division multiplexing (FDM) The deriving of two or more simultaneous, continuous channels from a transmission medium by assigning a separate portion of the available frequency…
frequency-exchange signaling Frequency-change signaling in which the change from one significant condition to another is accompanied by decay in amplitude of one or more frequencies…
frequency-hopping spread spectrum A signal structuring technique employing automatic switching of the transmitted frequency.
frequency-shift keying (FSK) Frequency modulation in which the modulating signal shifts the output frequency between predetermined values.
frequency-shift modulation Synonym frequency-shift keying.
frequency-shift signaling Synonym frequency-shift keying.
frequency-shift telegraphy Telegraphy by frequency modulation in which the telegraph signal shifts the frequency of the carrier between predetermined values. [NTIA] [RR]
frequently asked questions See FAQ file.
Fresnel diffraction pattern Synonym near-field diffraction pattern.
Fresnel reflection In optics, the reflection of a portion of incident light at a discrete interface between two media having different refractive indices.
Fresnel zone In radio communications, one of a (theoretically infinite) number of a concentric ellipsoids of revolution which define volumes in the radiation pattern…
front-end noise temperature A measure of the thermal noise generated in the first stage of a receiver.
front-end processor (FEP) A programmed-logic or stored-program device that interfaces data communication equipment with an input/output bus or memory of a data processing computer.
front-end security filter 1. [A] security filter logically separated from the remainder of an information system (IS) to protect system integrity.
front-to-back ratio 1. Of an antenna, the gain in a specified direction, i.e., azimuth, usually that of maximum gain, compared to the gain in a direction 180° from the…
FSDPSK Abbreviation for filtered symmetric differential phase-shift keying.
FSK Abbreviation for frequency-shift keying.
FTAM Abbreviation for file transfer, access, and management.
FTP File Transfer Protocol (ADP/Internet term).
FTP archive A collection of files that are available by using file transfer protocol (FTP). Synonyms file archive, file site.
FTP mail A method of accessing and retrieving FTP-based files via e-mail.
FTS (1) Flight Test Summary (2) Federal Telephone Service
FTS2000 Abbreviation for Federal Telecommunications System 2000. The designation for a defunct Federal telecommunications contract replaced by the contract…
FTS2001 Abbreviation for Federal Telecommunications System. A contract to provide a consolidated telecommunications capability to support Federal agencies with…
full carrier A carrier that is transmitted without reduction in power, i.e., a carrier that is of sufficient level to demodulate the sideband(s).
full carrier single-sideband emission A single-sideband emission without reduction of the carrier. [NTIA] [RR]

Sources

ATIS Telecom Glossary 2007 8,377 definitions
FCC Consumer Glossary of Communications 53 definitions