Telecommunications — page 71 of 85

Telecommunications terms

7001. single-harmonic distortion Of a fundamental frequency, the ratio of the power of a specified harmonic to the power of the fundamental frequency.
7002. Single-Level Device A device that is used to process data of a single security level at any one time.
7003. single-mode fiber Synonym single-mode optical fiber.
7004. single-mode optical fiber An optical fiber in which only the lowest order bound mode can propagate at the wavelength of interest.
7005. single-mode optical waveguide Synonym single-mode optical fiber.
7006. single-Morse system Synonym neutral direct-current telegraph system.
7007. single-polarized antenna An antenna that radiates or receives radio waves with a specific polarization. Note: For a singly polarized antenna, the desired sense of polarization is…
7008. single-sideband (SSB) emission An amplitude modulated emission with one sideband only. [NTIA] [RR]
7009. single-sideband (SSB) equipment reference level The power of one of two equal tones that, when used together to modulate a transmitter, cause it to develop its full rated peak power output.
7010. single-sideband (SSB) transmission Sideband transmission in which only one sideband is transmitted. Note: The carrier may be suppressed.
7011. single-sideband suppressed carrier (SSB-SC) transmission Single-sideband transmission in which the carrier is suppressed. Note: In SSB-SC the carrier power level is suppressed to the point where it is…
7012. single-tone interference An undesired discrete frequency appearing in a transmission channel. Note: The single-tone interference frequency is the frequency that appears in the…
7013. Sink Any process, activity, or mechanism which removes a greenhouse gas, an aerosol, or a precursor of a greenhouse gas or aerosol from the atmosphere.
7014. Site In archeology, any location of past human activity.
7015. six-bit byte Synonym sextet.
7016. skew In parallel transmission, the difference in arrival time of bits transmitted at the same time. 2.
7017. skew ray In a multimode optical fiber, a bound ray that travels in a helical path along the fiber and thus (a) is not parallel to the fiber axis, (b) does not lie…
7018. Skimming The act of obtaining data from an unknowing end user who is not willingly submitting the sample at that time.
7019. skin effect The tendency of alternating current to flow near the surface of a conductor, thereby restricting the current to a small part of the total cross-sectional…
7020. SKIP A non-digging bucket or tray that hoists material
7021. skip distance At a given azimuth, the minimum distance between the transmitting station and the closest point of return to the Earth of a transmitted wave reflected…
7022. skip zone An annular region within the transmission range of an antenna, within which signals from the transmitter are not received.
7023. Skipjack See Clipper
7024. sky wave A radio wave that travels upward from the antenna. Note: A sky wave may be reflected to Earth by the ionosphere.
7025. slab-dielectric waveguide An electromagnetic waveguide (a) that consists solely of dielectric materials, (b) in which the dielectric propagation medium has a rectangular cross…
7026. slamming The action that occurs when a customer's long-distance telephone service (carrier selection) is switched from one long distance company to another without…
7027. slant range The line-of-sight distance between two points, not at the same level relative to a specific datum.
7028. slave clock A clock that is coordinated with a master clock. Note 1: Slave clock coordination is typically achieved by phase-locking the slave clock output signal to…
7029. slave station In a data network, a station that is selected and controlled by a master station.
7030. slewing Rotating a directional antenna or transducer rapidly about one or more axes. 2. Changing the frequency or pulse repetition rate of a signal source. 3.
7031. sliding window A variable-duration window that allows a sender to transmit a specified number of data units before an acknowledgement is received or before a specified…
7032. SLIP Motion occurring along a fault plane.
7033. slip-free operation Operation of a communications system with sufficient phase-locking to avoid overflowing or emptying buffers.
7034. slit source Synonym line source.
7035. slope An inclined surface usually defined by the ratio of the horizontal distance to the vertical distance, i.e. 2:1 (2 horizontal units to 1 vertical unit).
7036. slope equalizer A device or circuit used to achieve a specified slope in a metallic transmission line.
7037. slope-keypoint compaction Data compaction accomplished by stating (a) a specific keypoint of departure, (b) a direction or slope of departure, (c) the maximum deviation from a…
7038. slot A fishing size limit where the angler may keep fish shorter than a minimum length but longer than an upper length limit.
7039. slot antenna A radiating element formed by a slot in a conducting surface or in the wall of a waveguide.
7040. slot time In networks using carrier sense multiple access with collision detection (CSMA/CD), the length of time that a transmitting station waits before attempting…
7041. slotted-ring network A ring network that allows unidirectional data transmission between data stations by transferring data in predefined slots in the transmission stream over…
7042. smart bot Abbreviation for smart robot. See bot.
7043. Smart Card A credit card size device which contains a microprocessor, memory and a battery.
7044. smart jack Synonym [loosely] continuity check transponder.
7045. smart robot See bot.
7046. SMDR Abbreviation for station message-detail recording.
7047. smearing In video displays, a localized distortion over a sub-region of the image, characterized by reduced sharpness of edges and spatial detail.
7048. SMIL Acronym for synchronized multimedia integration language. A protocol for downloading digitized streams or audio/video data files in the absence of a…
7049. smooth Earth Idealized surfaces, such as water surfaces or very level terrain, having radio horizons that are not formed by prominent ridges or mountains but are…
7050. SMS/800 Help Desk The organization that administers the SMS/800 system for the centralized management of Toll Free numbers.
7051. SMTP Simple Mail Transfer Protocol (computer term).
7052. SNA Abbreviation for systems network architecture. A proprietary communications architecture.
7053. sneak current In a communications circuit, an anomalous current that presents no immediate danger, but may cause improper operation or damage.
7054. sneak current protection Application of a protective device that is intended to limit currents that are too small to operate fuse links, stub cables, or the fuse of a fused…
7055. Snell's law A law of geometric optics that defines the amount of bending that takes place when a light ray strikes a refractive boundary, e.g.
7056. Sniffer The name of the filter program used by the Infoseek search engine to prevent spamdexing.
7057. SNMP Simple Network Management Protocol. A standard Internet protocol that facilitates communications between a system being managed and the management console…
7058. Snow Precipitation that consists of frozen flakes formed when water vapor accumulates on ice crystals, going directly to the ice phase.
7059. SNR Signal-to-Noise Ratio
7060. soft copy A nonpermanent display image, for example, a cathode ray tube display.
7061. Soft Dial Tone Numbers Numbers that permit restricted dialing, such as calling emergency services and sometimes receive incoming calls (FCC 00-104, ¶ 33).
7062. soft limiting See limiting.
7063. soft sectoring On magnetic disks, magnetic drums, and optical disks, the identification of sector boundaries by using recorded information.
7064. Softswitch See Call Agent
7065. Software Coded instructions (programs) that make a computer do useful work.
7066. software defined radio A radio consisting of a receiver and/or a transmitter, where each has the following properties, respectively: (a) the received signal is digitized and…
7067. software engineering (1) A discipline whose objectives are to define, create, and apply a welldefined methodology that addresses a software life cycle of planning…
7068. software package A package that consists of (a) one or more computer programs and possibly related material such as utility programs or tutorial programs, recorded on a…
7069. software piracy The unauthorized use, copying, or distribution of software products. [2382-pt.8]
7070. software tool Software, such as a computer program, routine, subroutine, program block, or program module, that can be used to develop, test, analyze, or maintain a…
7071. SOH A declaration from a client computer that asserts the computer's health status.
7072. solid-state scanning In facsimile, scanning in which all or a part of the scanning process is performed by electronic commutation of an array of solid-state photosensitive…
7073. soliton An optical pulse having a shape, spectral content, and power level designed to take advantage of nonlinear effects in an optical fiber waveguide, for the…
7074. sonar An acronym derived from the expression "sound navigation and ranging." Refers to the method or equipment for determining by underwater sound techniques…
7075. SONET Synchronous Optical Network.
7076. sonobuoy In sonar systems, a device (a) that is used to detect acoustic waves, such as those produced by ships and submarines, (b) that, when activated, relays…
7077. sound navigation and ranging See sonar.
7078. sound wave See acoustic wave.
7079. sound-powered telephone A telephone in which the operating power is derived from the speech input only.
7080. sounder prediction station A station equipped with an ionosphere sounder for realtime monitoring of upper atmosphere phenomena or to obtain data for the prediction of propagation…
7081. sounding A set of data measuring the vertical structure of an atmospheric parameter (temperature, humidity, pressure, winds, etc.) at a given time.
7082. Source Any place or object from which air pollutants are released. Sources that are fixed in space are stationary sources and sources that move are mobile…
7083. source efficiency In optical systems, the ratio of emitted optical power of a source to the input electrical power.
7084. source language In computing, data processing, and communications systems, a language from which statements are translated.
7085. source program A computer program written in a source language. Note: An example of a source program is a program that serves as the input to an assembler, compiler, or…
7086. source quench A congestion-control technique in which a computer experiencing data traffic congestion sends a message back to the source of the messages or packets…
7087. source user The user providing the information to be transferred to a destination user during a particular information transfer transaction.
7088. space In telegraphy, one of the two significant conditions of encoding. Note 1: The complementary significant condition is called a "mark.
7089. space diversity A method of transmission or reception, or both, in which the effects of fading are minimized by the simultaneous use of two or more physically separated…
7090. space operation service A radiocommunication service concerned exclusively with the operation of spacecraft, in particular space tracking, space telemetry and space telecommand.
7091. space radiocommunication Any radiocommunication involving the use of one or more space stations or the use of one or more reflecting satellites or other objects in space.
7092. space research service A radiocommunication service in which spacecraft or other objects in space are used for scientific or technological research purposes. [NTIA] [RR]
7093. space station A station located on an object which is beyond, is intended to go beyond, or has been beyond, the major portion of the Earth's atmosphere.
7094. space subsystem In satellite communications, that portion of the satellite link that is in orbit.
7095. space system Any group of cooperating Earth stations and/or space stations employing space radiocommunication for specific purposes. [NTIA] [RR] [47CFR]
7096. space telecommand The use of radiocommunication for the transmission of signals to a space station to initiate, modify or terminate functions of equipment on an associated…
7097. space telemetry The use of telemetry for the transmission from a space station of results of measurements made in a spacecraft, including those relating to the…
7098. space tracking Determination of the orbit, velocity or instantaneous position of an object in space by means of radiodetermination, excluding primary radar, for the…
7099. space-division multiplexing A misnomer. Note: Space-division multiplexing has been improperly applied to the use of multiple physical transmission channels, e.g.
7100. space-division switching In telephony, switching in which single transmission-path routing determination is accomplished in a switch by using a physically separated set of matrix…