S

S-VHS - Y/C (luminance/chrominance) signal processing (camera/VCR/monitor); yields better resolution and less noise than standard VHS

S-Video- Generic name for Y/C; applied to S-VHS or Beta ED

Sample Point - The raw data from an ADC used to calculate waveform points

Saticon - See TELEVISION CAMERA TUBES

Saturation - Quantity of pure color, which is diluted when mixed with white

Save - To store in a disk file, or on a NVRAM cartridge. If data is not saved, it will be lost when power to the computer is turned off

Scalar Computers - Computers designed to perform scalar processing, often in a large data processing environment. See SCALAR PROCESSING

Scalar Processing - The traditional method of computing in which one instruction is processed at a time

Sean - Examine character by character: move a light beam across the raster

Scrambling- Controlled distortion of a transmitted image in order to control reception; often used in pay channel distribution where an encoder is used to unscramble the picture on the receiving end

Screen Surfaces: Glass Beaded - Screen surface made up of very small glass beads to provide a bright image to a narrow viewing area

Screen Surfaces: Lenticular- Screen surface characterized by a lens-like embossed and silvered or aluminized surface to reflect maximum light over a wide horizontal and narrow vertical angle. Must be held very flat (tensioned) to avoid "hot spots"

Screen Surfaces: Mat or Matte White - Screen with flat, dull, non-shiny, non-glossy surface for even reflection over wide viewing angles

SCROLL - The smooth vertical movement of one or more lines of text on the screen.

SCSI - Small Computer System Interface: pronounced "scuzzy"

SECAM - Sequential Couleur a Memoire or sequential color and memory. A color TV system with 625 lines and 50 fields developed in France different from NTSC and PAL systems. Used in France, Russia and Eastern Europe

SEG - Special Effects Generator

Semiconductor Laser - A device that emits laser light under electrical stimulation. Applications include optical discs, bar code readers and optical communications.

Sensitivity - A rating given in dBV to express how hot" the microphone is by exposing the microphone to a specified sound field level (typically either 94dB SPL or 74dB SPL). This specification can be confusing because manufacturers designate the sound level different ways. Here is an easy reference guide: 94dB SPL =1 Pascal=10 microbars. To compare a microphone that has been measured at 94dB SPL with one that has been measured at 94dB SPL, simply add 20 to the dBV rating

Serial- A method of transmitting data bit-by-bit through a single communications channel

Shade- Color darkened with the addition of black or subtraction of light

Signal Generator (or Test Generator) - A test emulation device for injecting a signal into a circuit input; the circuit's output is usually identical to the actual device being emulated

Signal-to-Noise Ratio (S/N Ratio) - The ratio, measured in decibels, between the signal audio or video) and the noise accompanying the signal. The higher the S/N ratio, the better

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Silent Speed (Motion Picture Projectors) - A slower speed used to conserve film when sound is not a consideration. Almost never used in professionally produced films. Silent speed for 16 and 8mm film per ANSI Standards PH22.9 and 22.10 is 18 fr/s. There is no silent speed for 35mm film

Slave- A device or piece of equipment completely controlled by another device or piece of equipment, usually working in conjunction with that piece of equipment. Often a slave records signals from a master, as in tape duplicating

Slide Projector - A device containing a light source and lens system which focuses an image from a slide or transparency mounted in cardboard, glass, metal or plastic frame onto a screen. Some models have built-in rear viewing screens; some are provided with a high intensity light source for projection of large images, long throw, or when ambient light is high; some have random access or a built-in advance. The most common slide size is 2 x 2" (50 x 50mm). Slides may be contained in trays, cartridges, carousels or drums for use in appropriately designed projectors

Slide/Sync Recorder (or Visual/Sync Recorder) - An audio tape recorder capable of advancing one or more projectors on cue

SLR. Single lens reflex (camera)

SMDS - Switched Multimegabit Digital Service

SMPTE - Society of Motion Picture and Television Engineers

SNOBOL - String-Oriented Symbolic Language

Snow - Heavy random noise, causing static on a video signal

Soft Key - See FUNCTION KEY

Software - A set of instructions which controls a computer's Operation

Solar Cell - A semiconductor device that converts natural light to electricity. Pollution free and with low running costs, solar coils are used in desktop calculators, remote control units and artificial satellites.

Solids Modeling - Creating a three-dimensional representation of an object on a computer screen

Sound Advance (Motion Picture Projectors) - The physical distance in frames or inches that the sound is in advance of the corresponding visual. This is done because the sound bead and picture aperture cannot physically occupy the same space. Standards have been established: 16mm magnetic track, 28 frames; 16mm optical track, 26 frames; Super 8 magnetic track, 18 frames: Super 8 optical track, 22 frames. Sound advance on regular 8 magnetic track is 56 frames (not commonly used in the A-V industry)

Sound Filmstrip Projector - A filmstrip projector with an accompanying or built-in source of sound (record player or tape recorder/player)

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Sound Slide Projector- A slide projector with an accompanying or built-in source of sound record player or tape recorder/player). In most cases the sound unit controls the slide advance automatically, usually by the 10001-k system

Sound Speed (Motion Picture Projectors) -24 frames per second (fps) in the United States. This applies to 35mm, 16mm and Super 8. Some Super 8 systems operate at 18 fps as well as 24 fps. See appendix for running times Speech Compression and Expansion - A method of electronically correcting the pitch as the playback of standard tape is changed in order to keep the faster (compressed) or slower (expanded) speech intelligible; speeds range from half of normal to 2 1/2 times normal

SPL - Sound Pressure Level is the loudness of sound relative to a reference level of 0.0002 microbars.

Square Wave- A common wave shape consisting of repeating square pulses

Standards - Uniform specifications to permit interoperability in videoconferencing that is manufacturing independent.

Stereo - Equipment with separate signals and channels for the left and right audio information

Still Frame - A term for a captured frame of motion video or, less often, a still graphic image of any type. Also used to describe conferencing systems restricted to this mode of transmission and display.

Studio System - Studio video teleconferencing is usually built into a conference room or gallery setting to accommodate a large number of users. The monitor size and/or projection system is a determining factor for audience size. Two monitors are used, one showing the conferees and the other showing the information being discussed.

Subcarrier- The portion of the composite video signal which contains the color information. The frequency of this signal in the NTSC system is 3.579545MHz

Supercardioid Microphone- A unidirectional microphone with tighter front pickup angle (115°) than a cardioid, but with some rear pickup. Angle of best rejection is 126° from the front of the microphone, that is, 54° from the rear

Super Slides. One of the popular formats for mounting 2"x 2" slides in which the mounted size of the image is 38mm x 38mm

Super VHS - This type of tape gives a more detailed picture. Super VHS VCRs must be used with Super VHS tapes for optimum performance.

Superworkstation- A new generation of high-performance stand-alone workstation that incorporates a fast CPU, floating-point processing, superior graphics, networking and three-dimensional modeling capabilities

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Surface Attributes - Functions that give a life-like appearance to a computer generated object, including texture, translucency and light source simulation

Surround Sound - This refers to the simulation of the theater or concert experience by surrounding the listener with sound coming from different areas around the room.

Sweep - One horizontal pass of an electron beam from left to right across the CRT screen

Sweep Speed - Same as TIME BASE

Switched 56- A term commonly used to refer to 56Kbps public switched service. Also "Dual Switched 56" - An aggregate channel of 112Kbps bandwidth composed of two 56Kbps circuits; commonly the least expensive worldwide transmission mode for basic videoconferencing.

Switched Network - A network which allows any site connected to it to communicate with any other site connected to the same network. When a videoconference is conducted over a switched network, connections are made by "dialing" the other parties in a similar manner to that in which normal phone calls are made.

Switcher - A specific special effects generator which allows a director or operator to electronically manipulate and assign multiple incoming video camera signals

Synchronizer (Multi-Image Devices)- A single-function device which, with a tape recorder or other type of playback. operates other equipment; i.e., signals for a slide change. Has only decoding' ability (reads the signal on playback and translates it into commands). Often built into a programmer, the synchronizer tells the programmer when something is to happen, and the programmer determines what happens. It may also be built into a tape recorder. Compare with PROGRAMMER

Syntax - The structure of an instruction. If the user supplies commands to the computer without using the correct spelling or verbiage, the computer will often respond with a syntax error

System Disk - The primary program diskette. Many software programs include several diskettes; however, the main program resides on only one of them

T

T1- Commonly used transmission line for videoconferencing, with a capacity of 1,544Kbps.

T3 Channel (DS-3) - In North America, a digital channel which communicates at 45.304Mbps.

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T.120 - A family of proposed international standards for audiographic conferencing.

Tachistoscope- A device for exposing objects, words and phrases for a brief interval, usually fractions of a second. Some use a camera shutter or other mechanical means to "flash" material; others expose material briefly by moving images in and out of focus; some expose and then mask material; some control duration of illumination of material. All devices present controllable intermittent timed exposures and retain visual materials more rapidly and more accurately. Also see PACING DEVICE and CONTROLLED READING DEVICE

Tactile - Markings on keys

Tape Counter - A device driven by the tape recorder or playback mechanism which indicates the amount of tape run past the heads. 2X counter (ICIA recommended practice for compact cassette equipment indicates relative location on a tape and should advance 1 digit for every 2 revolutions of the supply spindle

Tape Deck - Tape recorder designed solely for use with an external or separate sound system; includes a transport mechanism with heads and pre-amplifier electronics

Tape Drive or Transport - The motor and mechanism that moves the tape at the correct and constant speed and tension past the heads. Some transports have 3 motors, one each for the supply reel, take-up reel and capstan; others have a single motor with belts and pulleys or idler rollers to drive the reels and capstan

TCP/IP - Transmission Control Protocol/Internet Protocol, a standard communication protocol developed by DARPA (Defense Advanced Research Projects Agency)

Telecine- A video camera system specifically designed to pick up for viewing standard slides and motion picture film

Teleconferencing- The use of electronic channels to facilitate real-time communications among groups of people at two or more locations. Teleconferencing is a generic term that refers to a variety of technologies and applications, including audioconferencing, audiographics conferencing, videoconferencing, business television, and distance learning or distance education. (ITCA)

Television Camera Tubes: Image Orthicon- Early type of camera pickup tube, basically obsolete

Television Camera Tubes: Plumbicon - Trade name of N.V. Philips' special tube, more sensitive than a Vidicon; used in some color video cameras

Television Camera Tubes: Saticon - Tube with similar characteristics of a plumbicon, with special usage in 2/3"portable color cameras

Television Camera Tubes: Vidicon - The most common video camera pickup tube for translating the light focused on its target into electronic scanning lines for recording or reproduction on a picture tube

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Television Projector or Video Projector - A device which projects the video image onto a screen

Television Receiver - A device for reproducing both pictures and sound from broadcast television signals or a modulatedcable system; technically, the signal has to be broadcast to become television

Television Receiver Monitor - A combination allowing the viewer to switch from either closed circuit or broadcast signals

Test Generator - See SIGNAL GENERATOR

Texture Mapping The ability of a digital picture manipulator to create textured surfaces that can be applied to shapes

Threading (British "lacing") - Inserting or directing a film or tape through the projector or recorder mechanism, Threading may be of several kinds:

Threading - A computer program which requires the use of several subprograms

Threading. Manual - Requires the operator to thread film/tape through the machine a step at a time, around and

Threading. Self - Uses a cartridge or cassette from which the film is extracted and threaded automatically

Threading. Slot or Channel - Threading by placing film or tape in an open slot and operating one control to adjust mechanism. With Automatic Threading, the film must be inserted into an opening manually but is then transported automatically through the entire mechanism. With slot or automatic threading 16mm projectors, it is often necessary to feed the end of the film onto the take-up reel

Throw Distance - The distance from the center front side of the projector lens to the center of the screen

Time Base Corrector (Video) - Slight errors in the line-to-line position of video information occur between record and playback. At the time of playback, these appear as serrations which tend to make the edges of the image waver. This condition is referred to as "time base error," and the corrector smooths out the wavers.

Time Base Generator - A sync generator that puts a time clock signal on the videotape to refer precise horizontal lock-up of an image lime Code - A system of numbering video frames. SMPTE lime Code is an audio signal pulse recorded onto an audio track of the tape; Vertical Interval mine Code is recorded with the image on the video frame itself and is capable of identifying odd and even numbered fields. Vertical Interval Time Code (VITC) is considered the most accurate

Time Division Multiplex (Multi-Image Devices) - A form of programming where the signal is pulsed with varying interspersed intervals of time to produce commands. Compare with FREQUENCY DIVISION MULTIPLEX

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Time Lapse Recorder - A video recorder modified to permit intermittent sampling of video information. Used primarily for security and surveillance

Tint - Saturation; amount of white in a color

Toggle - To alternate or switch back and forth between two modes. Many keys on the computer are often used as "toggles" to switch various functions on/off

Tone - Amount of black (shade) and white (tint) in a color

Touch Panel Switch - Replaces the conventional push ­buttons and other manual switches; works by capacitance, resistance or physical contact

Trace - The visible shapes drawn on a CRT by the movement of the electron beam. Trace lines are also known as video lines on a CRT

Track - The path of a recorded signal on film, tape or disc. Audio on tape is ordinarily along a straight longitudinal track; video on tape is ordinarily along a helical or diagonal track; the track on a disc is spiral. In reproduction, the responder must track or follow the recorded signal accurately.

Tracking Control - This feature adjusts tape speeds and cleans out picture "jitter".

Transducer - A device that converts a specific physical quantity such as sound, pressure, strain, or light intensity into an electrical signal

Transforms- A set of functions that allows a user to manipulate an image on the display. Common features include zooming, panning, and rotation

Transmission Speed - Data rate for videoconferencing, usually expressed in kilobits per second.

Trigger - The circuit that initiates a horizontal sweep on an oscilloscope and determines the beginning point of the waveform horizontal scan lines, 50 frames per second written 625150). Used in Western Europe, Australia, parts of Africa, the Middle East and Brazil

V

Video Standards SECAM - Sequential Couleur a Memoire Sequential Color and Memory) - 625 horizontal scan lines, 50 frames per second (625I50~ similar to PAL but differs greatly in method of producing color signals. Used in Saudi Arabia, USSR and France

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Video Tape Recorder (VTR) - A device which accepts signals from a video camera and a microphone and records Images arid sound on videotape in the form of reels, cassettes or cartridges. It can then play back the recorded program for viewing on a video monitor or receiver. Some machines have modulators for feeding a video receiver directly. Also called a Television Tape Recorder

Video Teleconferencing - A form of conferencing that employs voice and video communications, usually accomplished using digital channels (ISDIN).

Vidicon - See TELEVISION CAMERA TUBES Viewing Angle - Screens do not reflect equally in all directions. Most light is reflected in a conical volume centered around the 'line of best viewing" or along the on axis". A viewer located along the surface of the cone sees only 50 percent of the maximum brightness. A viewer located outside the cone sees less than 50 percent of maximum brightness. Curved screens usually have smaller viewing angles than flat screens

Virtual Memory - A technique by which the CPU does not require an entire process or program be loaded into RAM. This technique, which breaks the active processes into pieces, brings data into main memory as needed from the disk. It allows very large programs to be executed.

VITC - Vertical Interval Time Code. See TIME CODE VLSI - Very Large Scale Integration. See also IC VLSIC - Very Large-Scale Integrated Circuits. V-Mail Video MaiIi - A term used to describe the delivery of messages containing video content over digital networks, often to the user's desktops. These may be real time, time shifted, stored and forwarded, or any combination of above.

Voice-Activated Switching - In multiway videoconferencing, used so that all participating sites automatically see the site which is currently speaking. Volt - The unit of electrical potential difference Voltage - The difference in electrical potential, expressed in volts, between two points

Volume Unit Meter (VU Meter) - A device for sound systems or recorders to indicate the relative levels of the various sounds being recorded or played. Usually calibrated to show a point of maximum recording level to avoid tape saturation and limit distortion.

VTR - Video Tape Recorder

W

Watt - A unit of electricity; power needed to maintain a current of one amp under the pressure of one volt Waveform - A graphic representation of a voltage varying over time

Windowing - A feature that allows several applications to simultaneously appear in separate sectors, or windows, on a computers display screen.

Wireless - A distribution system not depending on wires; may be AM, FM, infrared, magnetic or ultrasonic transmission

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Workstation - A desktop computer typically dedicated to a single engineer.

Wow - A low rate periodic disturbance in sound usually caused by regular variations in the rotation of some mechanical component of the system. Usually Wow and Flutter are combined; see FLUTTER

WWW (World Wide Web) - The universe of hypertext servers (HTTP servers) which are the servers that allow text, graphics, sound files etc. to be mixed together

WYSIWYG - What You See Is What You Get; when the visual image on a computer screen is what prints out

X

X-Axis - The horizontal reference in a 2-dimensional coordinate system

Xenon Arc Lamp - A point source arc lamp filled with high pressure Xenon gas. Xenon arc lamps have no filament. The arc is formed by electric current flowing through the Xenon gas between two tungsten electrodes. Used mainly in motion picture and slide projectors and follow spotlights for medium and high intensity applications.

XL-type Connector (also XLR or cannon) - A very sturdy and secure type of connecting jack, usually used in professional 'balanced' type audio systems. Incorporates three terminals, two for the signal and one for the system grounding.

Y

Y Signal - The luminance signal (as opposed to the chrominance signal transmitted in standard color video; in a color picture it is made up of 030 red, 0.59 green, and 0.11 blue and is compatible with a standard monochrome receiver.

Y-Axis - The vertical reference in a 2-D coordinate system

Y(C - Y=Luminance, C=Chrominance: Broadcast NTSC with separate color

Y. R-Y, B-v - CAV signals used in PAL systems as well as for some encoder and most decoder applications in NTSC systems; Y is the luminance signal, R-Y is the first color difference signal and B-Y is the second color difference signal.

Z

Z-Axis - The Z axis is in the third dimension, perpendicular to the X and V axes and indicates depth

Zoom - Usually a lens with a long focal length that allows the camera operator to move his view in on progressively smaller portions of the currently visible scene and subsequently move his view back out and view the entire scene. Only the lens moves~ the operator remains stationary

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