A metal plate filled with holes that perfectly match the phosphor groupings in a color television. The shadow mask, or aperture grill as it’s sometimes known, is used to keep the electron beams from straying into other phosphor groupings in a color cathode ray tube. Often the shadow mask is installed as part of the phosphor addition process because the tiny holes need to be perfectly aligned. A slight variance in the position of the shadow mask can greatly affect screen performance. (Glossary of Terms dot Net)
Shannon's Law
An arithmetic proof that defines the maximum data rate an analog device can achieve when sending information over a sampled, analog-to-digital connection when the analog device has no control over the timing of each individual sample. For the North American telephone system, which has a sample rate of 8,000 samples per second with a range of up to 128 sample values, Shannon's Law shows the maximum data rate that can be achieved over voice grade lines to be about 36Kbps.
Share
The percent of television households tuned to a particular program or category of programming.
Shared Wired Network
A topology where multiple households connect to a common piece of wire.
Sheath
An outer protective layer of a fiber optic cable. Also called the cable jacket. (FiberOpticsInfo)
Sheath Diagram courtesy of Fiber Optics Info, http://www.fiber-optics.info/fiber_optic_glossary/s
Sheave
A grooved wheel or pulley used when installing cable in underground plant. (Arris Glossary of Terms)
Shield
A sheet, screen or braid of metal, usually copper, aluminum or other conducting material placed around or between electric circuits or cables or their components, to contain any unwanted radiation, or to keep out any unwanted interference. (Arris Glossary of Terms)
Shield Coverage (Shield Percentage)
The physical area of a circuit or cable actually covered by shielding material, expressed in percent. (Arris Glossary of Terms)
Shop-At-Home
Programs allowing customers to view products and/or order them by cable TV, including catalogues, shopping shows, etc.
Short Circuit Current
A photo detector (PD) specification describing the current produced by a light source with defined optical power (typically rated in the number of lux) while the PD is operating with no bias voltage applied (VD = zero (0)). (Zanger)
Short Form Video
A type of video content that lacks a content arc which in its entirety typically lasts less than ten (10) minutes. The experience is typically uninterrupted with linear video ads playing before or after, instead of during a break (mid-roll). (Fain)
Shot Noise
Noise caused by current fluctuations arising from the discrete nature of electrons. (FiberOpticsInfo)
Shrink Tubing
A plastic-based tubing which, when heated to a critical temperature, will shrink and form a weatherproof seal. Applied to connectors to protect the connection from any possibility of water infusion. Also known as heatshrink. (Arris Glossary of Terms)
Si
Silicon; generally used in optical photo detectors. Good for short wavelengths only (e.g., < 1000 nm). (FiberOpticsInfo)
SI
Service Information
SI
System Integrators
SI Units
Système Internationale (in English, International System of Units), commonly known as the metric system. (FiberOpticsInfo)
SiC
Silicon Carbide; a bluish-black crystalline compound, SiC, one of the hardest known substances, used as an abrasive and heat-refractory material and in single crystals as semiconductors, especially in high-temperature applications. (Answers dot com)
Read more: http://www.answers.com/topic/silicon-carbide#ixzz1H3gIp6VO
SID
Service Identifier
Sideband
Frequencies distributed above and below the carrier that contain energy resulting from amplitude modulation. The frequencies above the carrier are called upper sidebands, and the frequencies below the carrier are called lower sidebands. (FiberOpticsInfo)
Side Lobe
A construct used to describe an antenna's ability to detect off-axis signals. The larger the side lobes, the more noise and interference a dish can detect. High side lobe rejection is a desirable antenna characteristic. (Arris Glossary of Terms)
SiGe
Silicon Germanium; a semiconductor material made from silicon and germanium. Germanium is very similar to silicon, but when one layer is grown on top of the other to form the base of the transistor, the resulting transistor can switch faster and yield higher performance. SiGe transistors are compatible with standard fabrication processes and are built on the same chip with silicon transistors to create high-frequency circuits. Only a handful of SiGe transistors are used in mobile phones, while tens of thousands are used in optical switches, DACs and ADCs. (PCmagazine)
Signal
Any visible or audible indication which can convey information. Also, the information conveyed through a communication system. (Arris Glossary of Terms)
Signal Leakage
Undesired emission of signals out of a cable television system.
Signal Level
The RMS voltage signal level, usually expressed in dBmV. (Arris Glossary of Terms)
Signal Level Meter (SLM)
A tuned radio frequency voltmeter, usually calibrated in decibels per millivolt (dBmV) as well as voltage. (Arris Glossary of Terms)
Signal Switching Point (SSP)
SSPs are points within the signaling system number 7 (SS7) network that terminate SS7 signaling links and also originate, terminate, or tandem switch calls.
Signal-to-Noise Ratio (S/N)
The ratio of usable signal power to extraneous noise power in a specified bandwidth, indicating picture quality, usually expressed in decibels. Also referred to as SNR. (Arris Glossary of Terms)
Signal Transfer Point (STP)
A STP is a node within signaling system number 7 (SS7) network that routes signaling messages based on their destination address. It is essentially a packet switch for SS7. It may also perform additional routing services such as Global Title Translation.
Signaling
The process by which an end system notifies a network that it wants service.
Signaling Connection Control Part (SCCP)
This is a protocol within the signaling system number 7 (SS7) suite of protocols that provides two functions: (1) The ability to address applications within a signaling point. (2) Global Title Translation.
Signaling Gateway (SG)
A signaling agent that receives/sends switched circuit network (SCN) native signaling at the edge of the Internet protocol (IP) network. In particular the signaling system number 7 (SS7) SG function translates variants ISUP and TCAP in an SS7-Internet Gateway to a common version of ISUP and TCAP.
Signaling System Number 7 (SS7)
SS7 is an architecture and set of protocols for performing out-of-band call signaling with a telephone network.
Signal-to-Noise Ratio (SNR)
The sensitivity of a communications receiver is generally specified in terms of the audio signal-to-noise ratio that results from an input signal of a certain number of microvolts.
Signed and Sealed
An “envelope” of information which has been signed with a digital signature and sealed using encryption.
Silica Glass
Glass made mostly of silicon dioxide, SiO2, used in conventional optical fibers. (FiberOpticsInfo)
SILVO
An organization formed in the mid 1980's to monitor frequency re-use. (Satnews)
Simple Gateway Control Protocol (SGCP)
A call signaling protocol used for controlling media gateways from a call agent (or Call Management Server) within the network. SGCP was the precursor to the PacketCable Network-based Call Signaling (NCS) protocol.
Simple Mail Transfer Protocol (SMTP)
A TCP/IP protocol used to send e-mail on a network or to route e-mail on the Internet.
Simple Network Management Protocol (SNMP)
SNMP allows a TCP/IP host running an SNMP application to query other nodes for network-related statistics and error conditions. The other hosts, which provide SNMP agents, respond to these queries and allow a single host to gather network statistics from many other network nodes.
Simplex
A circuit which can carry information in only one direction; for example, broadcasting. (Arris Glossary of Terms)
Simplex Cable
A term sometimes used for a single-fiber cable. (FiberOpticsInfo)
Simplex Transmission
Transmission in one direction only. Also referred to as half-duplex transmission. (FiberOpticsInfo)
Simplex Transmission Diagram courtesy of Fiber Optics Info, http://www.fiber-optics.info/fiber_optic_glossary/s
Single Attachment Concentrator
A concentrator that offers one attachment to the FDDI network. (FiberOpticsInfo)
Single Channel Amplifier
A narrow-band amplifier which is tuned to boost the signal strength of one particular television channel. (Arris Glossary of Terms)
Single-Channel-Per-Carrier (SCPC)
A method used to transmit a large number of signals over a single satellite transponder. (Satnews)
Single-line Laser
See single-longitudinal mode laser.
Single-longitudinal Mode Laser (SLM)
An injection laser diode which has a single dominant longitudinal mode. A single-mode laser with a side mode suppression ratio (SMSR) < 25 dB. (FiberOpticsInfo)
SLM Graph of Relative Output versus Wavelength courtesy of Fiber Optics Info, http://www.fiber-optics.info/fiber_optic_glossary/s
Single-Mode Fiber (SMF)
An optical waveguide through which only one mode will propagate. Single-mode waveguide is produced by reducing the diameter of the core of the waveguide to 2 to 10 microns. The diameter of the core is dependent on the difference in the refractive index of the core and cladding. As the difference in the refractive index of the core and cladding decreases, the diameter of the core increases. Theoretically, the core could be infinitely large as the difference in index become infinitely small. Single-mode operation is desirable because all modes except the lowest and simplest mode are excluded. This reduces time distortion of signals propagating in unwanted modes, retains phase relationships, and reduces dispersion to the lowest possible value. (Arris Glossary of Terms)
Single-mode Optical Loss Test Set (SMOLTS)
An optical loss test set for use with single-mode fiber. (FiberOpticsInfo)
Single Sideband (SSB)
A form of amplitude modulation (AM) whereby one of the sidebands and the AM carrier are suppressed. (Satnews)
SIP
Session Initiation Protocol
Skew
An adjustment that compensates for slight variance in angle between identical senses of polarity generated by two or more satellites. (Satnews)
Skew Angle
The angle at which photoelectric sensors are aligned to prevent light from being reflected back to the sensor from the object during retroreflective sensing; also, the angle a measured part is positioned away from the coordinate system of the measuring instrument. (Photonics dot com)
Skin Effect
The behavior whereby electricity migrates to the outside wall of a wire. Link to an SCTE sponsored primer on skin effect: http://www.scte.org/mmpres/Primer/SkinEffect/index.html
Sky Filter
A filter designed to decrease the luminosity of the sky without decreasing that of the landscape in the foreground. A filter that has a depth of tint that decreases from top to bottom is used in black and white photography, while a neutral density filter is used in color applications. (Photonics dot com)
Slab Dielectric Waveguide
A waveguide with a rectangular cross section that is composed entirely of dielectric materials. (Photonics dot com)
Slab Laser
Solid-state laser geometry in which the standard rod is replaced by a slab of laser material. Often called total-internal-reflection face-pumped laser (TIR-FPL). (Photonics dot com)
Slant Range
The length of the path between a communications satellite and an associated earth station. (Satnews)
SLED
See surface-emitting diode.
Slit
An aperture, usually rectangular in shape, with a large length-to-width ratio, and a fixed or adjustable shape through which radiation enters or leaves an instrument. The aperture is generally small as compared to the light source. (Photonics dot com)
SLM
See single-longitudinal mode laser.
Slope
The difference between signal levels at the highest frequency and at the lowest frequency in a cable system. Also called spectrum tilt. (Arris Glossary of Terms)
Slope-compensation
The action of a slope-compensated gain control, whereby slope of amplifier equalization is simultaneously changed with the gain so as to provide the correct cable equalization for different lengths of cable; normally specified by range and tolerance.
Slope Efficiency (SE)
The mean value of the incremental change in optical power for an incremental change in forward current when the device is operating in the lasing region of the optical power output versus forward current curve. Also referred to as differential efficiency. (FiberOpticsInfo)
Slot
That longitudinal position in the geosynchronous orbit into which a communications satellite is "parked". Above the United States, communications satellites are typically positioned in slots which are based at two to three degree intervals. (Satnews)
Slow-Scan Television
A television system that uses a slow rate of horizontal scanning to increase its reproduction and transmittance accuracy of printed matter, photographs and illustrations. (Photonics dot com)
SMA (Optical)
A threaded type of optical connector. One of the earliest optical connectors to be widely used. Offers poor repeatability and performance. (FiberOpticsInfo) Amphenol developed the SMA from the "Subminiature A" hence SMA, microwave connector. The model 905 had a machined ferrule exactly 1/8 inch in diameter that mated in a machined adapter. When the adapters were not precise enough for better fibers, a necked-down ferrule that mated with a Delrin adapter for better insertion loss performance was offered. Optical SMA connectors are still in use on some military and industrial systems. (Fiber Optic Association)
Photograph of Optical SMA Connectors courtesy of The Fiber Optic Association, http://www.thefoa.org/tech/connID.htm
Small Office/Home Office (SOHO)
An industry term used to refer to a telecommunications market segment comprised of people working out of their homes or small offices.
Smart Structures
Also smart skins. Materials containing sensors (fiber optic or other types) to measure their properties during fabrication and use. (FiberOpticsInfo)
SMATV
Satellite Master Antenna Television System; The adding of an earth station to a MATV system to receive satellite programs. (Satnews)
Smear
A term used to describe a picture condition in which objects appear to be extended horizontally beyond their normal boundaries in a blurred or “smeared” manner.
SMD
Surface-Mount Device; see SMT. (FiberOpticsInfo)
SMG
Subscriber Media Gateway
SMPTE
Society for Motion Picture and Television Engineers
SMPTE 259M
Television standard, written by the Society of Motion Picture and Television Engineers (SMPTE), that describes a serial digital interface (SDI) for 10-bit 4:2:2 component and 4fsc composite digital transport. (FiberOpticsInfo)
SMPTE 310M
Television standard, written by the Society of Motion Picture and Television Engineers (SMPTE), that describes a synchronous serial interface for MPEG-2 digital transport streams. (FiberOpticsInfo)
SMS Spam
Sometimes called cell phone spam; any junk message delivered to a mobile phone as text messaging through the Short Message Service (SMS). The practice is fairly rare in North America, but has been common in Japan for years. In 2001-2002, the systems at DoCoMo, the country's major service provider, were overcome by the volume of SMS spam, causing users' screens to freeze and spreading programs that caused the phones to dial emergency numbers.
Text messaging has greatly increased in popularity in the past five years and the government is trying to keep up with rapidly changing technology. Although SMS spam is less prevalent than email spam, it still accounts for roughly 1% of texts sent in the United States and 30% of text messages sent in parts of Asia. In the United States, SMS spam messages have been illegal under the Telephone Consumer Protection Act since 2004. Citizens who receive unsolicited SMS messages can now bring the solicitors to small claims court. In 2009, China’s three main mobile phone operators (China Telecom, China Mobile Ltd and China Unicom) signed an agreement to combat mobile spam by setting limits on the number of text messages sent each hour. (Target)
SMS
Spectrum Management System
SMT
Surface Mount Technology
S.MTA
Standalone Multimedia Terminal Adapter
SMTP
Simple Mail Transfer Protocol
SNA
Systems Network Architecture
SNAP
Subnetwork Access Protocol
SNG
Satellite News Gathering; usually with a transportable uplink truck. Sometimes referred to as a “SNG van” or “SNG truck”. (Satnews)
SNMP
Simple Network Management Protocol
Snow
Heavy random noise displayed on a video or television monitor.
SNR
Signal-to-Noise Ratio
SOC
System On A Chip
SOC
Selectable Output Control
Society for Cable Telecommunications Engineers (SCTE)
A non-profit professional organization serving the cable industry by providing training, certification and standards.
Society for Motion Picture and TV Engineers (SMPTE)
A professional society for motion picture and TV engineers with more than 9,000 members worldwide. It prepares standards and documentation for TV production. SMPTE time code records hours, minutes, seconds and frames on audio or videotape for synchronization purposes.
Software
Programming and programming materials such as films, videotapes, and slides.
SOHO
Small Office/Home Office
SoI
Silicon on Insulator; a semiconductor manufacturing technology in which thin films of single-crystalline silicon are grown over an electrically insulating substrate. (Answers dot com) Read more: http://www.answers.com/topic/silicon-on-insulator#ixzz1H3em0Nwk
Solar Outage
Solar outages occur when an antenna is looking at a satellite, and the sun passes behind or near the satellite and within the field of view of the antenna. This field of view is usually wider than the beamwidth. Solar outages can be exactly predicted as to the timing for each site. (Satnews)
Solid State
A term taken from physics, used interchangeably with the word transistorized; also includes other semiconductor elements, such as diodes. Generally refers to non-vacuum tube equipment.
Soliton Pulse
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 purpose of essentially negating dispersion over long distances. (FiberOpticsInfo)
SONET
Synchronous Optical NETwork. A worldwide standard of digital communication utilizing optical interfaces. (Arris Glossary of Terms)
SOS
Silicon on Sapphire; a hetero-epitaxial process that consists of a thin layer of silicon grown on a sapphire (Al2O3) wafer. SOS is part of the Silicon on Insulator (SOI) family of CMOS technologies. SOS is primarily used in military and space applications because of its inherent resistance to radiation. SOS has seen little commercial use to date because of difficulties in fabricating the very small transistors used in modern high-density applications. This drawback is because the SOS process results in the formation of dislocations from crystal lattice disparities between the sapphire and silicon. (Word IQ)
SOT-115J
The acronym “SOT” refers to “Small Outline Transistor” and is a JEDEC standard class of packaged electronic device. SOT-115J is not an official JEDEC package designation. Philips Semiconductor coined the designation “SOT-115J” in the 1990s to define the cable industry’s in-use since 1968 CATV hybrid amplifier module package outline and dimensions. The “SOT-115J” is neither small nor merely a transistor. Below is a dimensioned package outline drawing of the SOT-115J package (courtesy of RFMD). Link to RFMD website: http://www.rfmd.com/products/BroadbandTransmission/default.aspx
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