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Glossary of Terms

Glossary of Terms

5-wire Separate Horizontal & Vertical Sync
The signal: RGBHV = red, green, blue, horizontal sync (The sync pulses that control the horizontal scanning of the electron beam in a video device. NTSC standard is 15,75 kHz.) and vertical sync (Vertical sync is the timing pulse that triggers the electron beam to turn off and then return to the top of frame and start scanning the next frame or field.). This signal is referred to as full bandwidth RGB with separate sync. This is the height of signal quality and stability. This requires five cables to carry the signal. This can be thought of like the ""line king"" of the video food chain; everything after this is weaker.
S/N Ratio
Acronym for Signal-to-Noise ratio.
S-VHS
Super-Video Home System - A high band video recording process for VHS that increases the picture quality and resolution capability. See S-Video.
S-Video
Generic name for Y/C, applied to S-VHS or Beta E.
SaBRE
Acronym for Subtractive Bi-Refringent, Effect, a technology that allows two panels rather than three to generate the full 16 color VGA palette. The top panel provides white, magenta, blue, and cyan; the second provides colors from white through yellow and to red.
Saturation
The intensity of the color, or the extent to which a given color in any image is free from white. The less white in a color, the truer the color, or the greater its saturation. On a display device, it can be adjusted with the color control. Not to be confused with the brightness, saturation is the amount of pigment in a color, and not the intensity. Low saturation is like adding white to the color. For example, a low-saturated red looks pink.
Scan
In video, to move an electron beam across the raster in a camera or monitor. To feed visual information into a computer by means of an optical device called a scanner.
Scan Converter
Also called "video converter" or "TV converter", a scan converter is a device that changes the scan rate of a source video signal to fit the needs of a display device. Examples: computer-video to NTSC (TV), or NTSC to computer-video.
Scan Doubler
A device used to change composite interlaced video to non-interlaced component video, thereby increasing brightness and picture quality. Also called "line doubler".
Scan-Doubling
The process of making the scan lines less visible by doubling the number of lines and filling in the blank spaces. Also called "line doubling".
Script
Written instructions for visuals and audio in a video program multimedia presentation.
Scrolling
The displayed image (or interfering "noise" on the image) rolling constantly moving on the screen.
SCSI
Acronym for Small Computer System Interface.
SDA
Extron's product designation for System Distribution amplifier.
SDTV
Acronym for Standard-Definition Television
SECAM
Acronym for Systeme En Couleur Avec Memoire (sequential color with memory); the color TV system used in France and throughout the Eastern Block Republics.
SEG
Acronym for special Effects Generator.
Sequential Couleur Avec Memoire
Translated as "Sequential Color with memory". A composite color transmission system that potentially eliminates a need for both a color and hue control on the monitor. One of the color difference signals is transmitted on one line and the second is transmitted on the second line. Memory is required to obtain both color difference signals for color decoding. This system is used in France, Africa, Asia, Russia, Saudi Arabia and many Eastern European countries. Similar to PAL, but produces color signals in a different manner, 625 horizontal scan lines, 50 fields per second (625/50).
Serial
A method of transmitting data bit-by-bit through a single communications channel.
Serial Data
A way to transfer information by breaking the characters of a word into bits which are then transmitted sequentially along a single line. Compare to parallel, which uses more than one line.
Serial Port
An input/output connection on the computer that allows it to communicate with other devices in a serial fashion - data bits flowing on a single pair of wires. The serial port is used with RS-232 protocol.
Serration
A vertical synchronizing pulse divided into a number of small pulses, each acting for the duration of half a line in a television system. Serrations are used to keep the horizontal oscillator synchronized during the vertical sync pulse interval in early televisions.
Serration Pulse Removal Switch
A switch on certain Extron interfaces that removes the incoming serration pulses from the computer video source.
Shadow Mask
A metal plate with holes or vertical lines that is used to determine exactly where the electron beam strikes the CRT screen.
Shareware
Computer software distributed with the intention that the user will pay a fee to the program author if the program is considered useful or satisfactory by the user. This type of software is typically available on electronic bulletin boards.
Sharpness
The definition of the edges of an image. Also see "peaking".
Sharpness Control
Same as peaking control.
Shiftlock
An Extron feature used to lock video displays together when using Extron's VideoShift.
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 audio or video signal and the noise accompanying the signal. The higher the S/N ratio, the better the quality of the sound or picture.
Simulation
Representation of a situation, device, or system with a high degree of realism. Allows users to learn or practice the operation of equipment without damaging it or encountering other harmful consequences.
SL
Extron's product designation for ShiftLock.
SLR Connector
A type of audio connector featuring three leads, two for the signal and one for overall system grounding. A secure connector, often found on high quality audio and video equipment. Also called cannon connector.
Small Computer System Interface
An industry-standard input/output bus for peripheral computer devices, such as hard disk and CD ROM drives. A standard peripheral bus on Mac computers.
SMPTE
Acronym for Society of Motion Picture and Television Engineers.
SMPTE Pattern
The video test pattern consisting of color, black and white bands used as a standard for setting up video equipment.
Snow
Visual "noise" in a video picture giving the appearance of white flacks of snow.
Society of Motion Picture and Television Engineers
SMPTE. Society of Motion Picture and Television Engineers. A global organization, based in the United States, that sets standards for baseband visual communications. This includes film as well as video standards.
Software
The programs used to instruct a processor and its peripheral equipment to perform prescribed operations.
Spartial Resolution
Spartial resolution is a measurement of the total number of imagesels displayed in an entire image, usually noted in terms of horizontal by vertical (640 x 480).
Speaker
A device in a projector that gives life to displayed images by emitting sound.
Special Effects Generator
A video mixing device that allows switching among several cameras and a variety of special effects such as dissolves, fades, wipes and inserts.
Spectrum
The range of electromagnetic radio frequencies used in transmission of voice, data and television. Most is in the 900 MHz range.
Split Screen
A video effect where portions of images from two sources divide the screen.
Square Wave
A common wave shape consisting of repeating square pulses.
Stamper
Disc that is used to mold final replicated discs, and which is made from the mother disc.
Standard Definition Television
A subset of thye ASTC's standatd for DTV. SDTV refers to digital signals with about the same picture quality as analog NTSC images. Several ADTV programs can be broadcast in the spectrum space taken up by a single HDTV program. All HDTV sets will also reproduce SDTV programs.
Stereo
An audio playback technology that divides sound into two or more sources, creating a more realistic sound.
Still
In video, the term "still" is used as opposed to "motion" because there can be a difference in the way these two types of video are processed for the best viewing results, especially when the video is line-doubled or line-quadrupled. Still video includes text and slide presentations, while motion would include movies and TV programs. See "motion".
Still Frame
One film or video frame (1/24 or 1/30 of a second, respectively) presented as a single, stationary image).
STN
Acronym for SuperTwist Nematic.
Strike
In the audio/video business, a term for taking down an installation, for example at a show.
Sub-Carrier
The modulation sidebands of the color sub-carrier containing the R-Y and B-Y information.
Sub Menu
Menu(s) that enable the user to branch to a new information location without returning to the main menu.
Subnet Mask
A bit mask used to select bits from an Internet address for sub-net addressing. The mask is 32 bits long and selects the network portion of the Internet address and one more bits of the local portion. Sometimes called an address mask.
Subtractive Color
The process of creating a full color gamut by starting with white light and filtering out the unwanted components, instead of adding red, green, and blue together. This is exactly the same principle used throughout the typical printing and color photography processes.
Subtractive Color Process (CMYK)
Used in color printing, all desired colors are produced by mixing Cyan, Magenta, Yellow and Black. Examples: 0% of C, M, Y and K = white (no ink); 100% of C and M = red; 100% C, M and Y = process black. Also see "additive color" (RGB).
Subwoofer
An audio device dedicated to replicating the lowest, deepest sounds ascertainable by the human ear.
Super VGA
(SVGA - A term used to denote higher than VGA (640 x 480) resolution. Most Super VGA computers/cards output resolutions up to 1280 x 1024 and 16 million colors.
Superimposition
Placing one image over another so that both may be seem simultaneously. The effect can be achieved in many ways: by more than one exposure on a single piece of film, by multiple printing, or by registered projection. Abbreviated "super".
SuperTwist Nematic
An LCD type that is required to display high density, high multiplex rate video information. Unlike common LCDs with a ninety degree light rotation angle (used in watches and calculators), STN panels have a static "off" light rotation of between one hundred eighty degrees and two hundred seventy degrees.
SVGA
A video resolution equating to 800x600 imagesels in size; acronym for Super VGA.
Sweep
One horizontal pass of an electron beam from left to right across the CRT screen.
Sweep Signal
A signal whose frequency is varied through a given frequency range. The process of orienting the transmitter and receiver circuits in the proper manner in order that they can be synchronized. Home television sets are synchronized by an incoming sync signal with the television cameras in the studios 60 times per second. The horizontal and vertical hold controls on the television set are used to set the receiver circuits to the approximate sync frequencies of incoming television picture and the sync pulses in the signal then fine tune the circuits to the exact frequency and phase.
Switched 56
Switched 56 service allows customers to dial up and transmit digital information up to 56,000 bits per second in much the same way that they dial up an analog telephone call. The service is billed like a voice line-a monthly charge plus a cost for each minute of usage. Nearly all LECs and IXCs offer switched 56 service and any switched 56 offering can connect with any other offering, regardless of which carrier offers the service.
Switcher (1)
A device which allows the selection between more than one source, such as: video cameras, VCRs, etc. In audio/video, a means of selecting an input source and connecting it to an output device or a system. Also see "matrix switcher".
Switcher (2)
Term often used to describe a special effects generator; a unit which allows the operator to switch between video camera signals. Switchers are often used I industrial applications to switch between video camera monitoring certain areas for display on a monitor, or system of display devices. These kinds of switchers do not have sync generators.
Sync
In video, a means of controlling when things happen with respect to other things. Usually done with timing pulses to insure that each step in a process occurs at exactly the right time. For example: horizontal sync determines exactly when to begin each horizontal line (sweep) of the electron beam. Vertical sync determines when to bring the electron beam to the top-left of the screen to start a new field. There are many other types of sync in a video system. (Also called "sync signal" or "sync pulse".)
Sync Generator
An electronic circuit that produces sync impulses.
Sync on Green
The signal: RGsB = red, green, blue and composite sync added to the green channel. This signal is referred to as full bandwidth RGB with sync on green. This too is close to the height of signal quality, but stability may suffer a bit because we have added the two sync signals together, and then added that to the green channel. This signal requires three cables to carry the entire signal. We're descending the food chain, getting weaker still.
Sync-On-Green Switch
A switch on certain Extron interfaces that allows sync signal to be added to the green channel as required.
Sync Polarity
When a circuit is intended to function according to timing provided by a sync pulse, it can be designed to operate on the beginning (leading edge) or end (trailing edge) of that sync pulse. With some equipment, sync polarity (plus or minus) may be a selected through an option switch.
System Switcher
A switching device that communicates with other components in a system. For example, with communications between a switcher and a projector, the projector's remote control can command the switcher to change inputs. Also, the projector can be turned on/off by a command from the switcher.
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