a letter for terms starting with that letter:
| B | C
| D | E
| F | G
| H | I
| J | K
| L | M
| N | O
| P | Q
| R | S
| T | U
| V | W
| X | Y
- A -
Acronym for American National Standards Institute.
The ratio of width to height of a frame or screen. The most
common aspect ratios for projectors are 4:3, 5:4 and 16:9.
Acronym for Air Transport Association. The ATA adopts and
maintains content protection standards for luggage that can
be carried aboard commercial jetliners.
Acronym for Alternating Current.
A type of signal transmission circuit that block the DC
component of a signal but uses the dynamic ( AC)
component. Useful for observing an AC signal
that rides on a DC signal.
To retrieve information from a storage medium, such as videodisc,
videotape, computer disk or tape, or videotape.
The total time required to locate, retrieve, and display data
after a retrieval command is given.
A process which uses a complex numerical algorithm (a set
of mathematical relationships) to generate signals that control
all imagesels simultaneously.
An LCD technology that uses a transistorized
storage element (Thin Film Transistor) in each imagesel to
achieve precise control of the voltage applied. Active-matrix
LCD projection panels have response times
which allow viewing of animation, rapid mouse movement, and
Acronym for analog-to-digital converter. A circuit that converts
analog values to digital values. Also Extron's
product designation for Analog Distribution Amplifier
The shared component in a system that handles host interface
and communication connection functions. Also an interface
between two sources.
Color Process (RGB)
A color generation process used in video that combines Red,
Green and Blue to make all colors. All three colors (red,
green and blue) at 100% present a white image on a video screen.
The absence of all three colors presents a black image. See
Subtractive Color (CYMK).
A notation (usually alphanumeric or numeric) that identifies
a location of stored data in a storage device. Also
a frame number or time code that identifies the location of
video and/or audio data on tape or disc. To manage the storage
of data, e.g., "That buffer can address 4 megabytes."
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 subnet mask.
Acronym for Automatic Gain Control.
Acronym for American Wire Gage.
Jagged edges in text and also along the outer boundaries of
diagonal or curved objects. Anti-aliasing refers to software
adjustments that correct this effect. Caused by inadequate
sampling techniques in computer-produced images. Basically,
a false representation of a signal because of insufficient
sampling of high frequencies or fast transitions, typically
caused by lack of sufficient memory.
A flow of electricity which reaches maximum in one direction,
decreases to zero, then reverses itself and reaches maximum
in the opposite direction. The cycle is repeated continuously.
The number of cycles per second is the frequency. The average
value of voltage during any cycle is zero.
National Standards Institute (ANSI)
A science organization that sets measurement standards. For
example, ANSI Lumens represents a brightness measurement made
using ANSI methods. ANSI developed three-character lamp codes
to identify lamps that meet particular application requirements,
Standard Code for Information Interchange (ASCII)
The standard, eight-bit data character code-system that is
used internationally to transfer information through the use
of binary values between data processing systems. It is the
most commonly used format for PC files. The standard code
consisting of 7-bit coded characters (8 bits including parity
check), utilized to exchange information between data processing
systems, data communication systems, and associated equipment.
The ASCII set contains control characters and graphic characters.
Wire Gage (AWG)
A measure of the diameter of an electrical conductor. The
larger the gauge number, the smaller the conductor diameter.
Refers to the atomic structure of silicon of which TFTs (thin
film transistors) are made. Without definite form or shape
and not crystallized. In the context of solids, the molecules
are randomly arranged as in glass, rather than periodically
arranged, as in a crystalline material.
The measured magnitude of an amount or strength of a signal.
In electronics, amplitude usually refers to either voltage
A unit of measurement for electrical current.
A continuous signal that takes time to make a transition from
one level to another. Standard audio and video signals are
analog. An analog signal has an infinite number of levels
between its highest and lowest value. Analog signals cannot
consistently and accurately be represented digitally.
A continuous-scale electrical signal carrying images and sounds.
The use of physical variables such as voltage or current
to represent numerical values.
An NTSC/PAL to VGA
Converter with a built-in scan-doubler.
A device used to convert analog signals to digital signals.
A digital electronic component that converts an electrical
signal (analog) into discrete binary values (ones and zeros).
Acronym for American National Standards Institute.
A networking protocol developed by Apple
Computer for communication between Apple computer brand
products and other companies' computers. This protocol is
independent of what network it is layered on so it is "cross-platform
or platform independent".
A short program written in Java that is attached to a World
Wide Web page and executed by the visitor's browser.
Application sharing is a feature that allows two people to
work together when one of the individuals doesn't have the
same application, or the same version of the application.
In application sharing, one user launches the application
and it runs simultaneously. Both users can input information
and otherwise control the application using the keyboard and
mouse. Although it appears that the application is running
on two PCs, it actually runs on only one while each user operates
as though the application were running on both PCs. Files
associated with the application can be easily transferred,
so the results of the collaboration are available to both
users immediately. The person who launched the application
can lock out the other person from making changes, so the
locked-out person sees the application running but cannot
The specific use of a technology to accomplish a task. Often
used when referring to software programs that perform a specific
task, such as word processing, database management, or graphics.
Program Interface (API)
A set of calling conventions defining how a service is invoked
through a software package.
Acronym for Application Program Interface.
Specific Integrated Circuit (ASIC)
Usually a fairly large IC that has been designed for a particular
specialized electronic function. These are often used to take
advantage of the right reliability and repeatability, low
power consumption, small size, high speed, and very low cost
associated with modern IC manufacturing capabilities.
Transfer Mode (ATM)
A high-speed (up to 155 Mbps), high-bandwidth, low-delay,
transport technology that can integrate multiple data types
(voice, video, and data). ITU has selected ATM as the basis
for the future broadband network because of its flexibility
and suitability for both transmission and switching. May be
used in the phone and computer networks of the future.
Acronym for Asynchronous Transfer Mode.
Acronym for American Standard Code for Information Interchange.
Acronym for Applications Specific Integrated Circuit.
The ratio of height and width of a frame or screen. Horizontal
dimension of a picture expressed relative to the vertical
dimensions. The aspect ratio for NTSC video is 3:4. and the
aspect ratio of HDTV is 9:16.
Acronym for Advanced Television Systems Committee. A group
formed in 1998 to explore the development of television systems
for the U.S. more advanced than the existing NTSC system.
Its work resulted in the DTV system adopted in 1996,
which incorporates SDTV and HDTV
The decrease in the magnitude of a signal. A decrease in signal
voltage during its transmission from one point to another.
Equipment that mixes multiple audio inputs and feeds back
composite audio to each station after removing the individual
station's input. This equipment may also be called a mix-minus
A term used when audio signals are tied to other signals,
such as video, and they are switched together. (The opposite
The section of a videodisk or tape that contains a sound signal.
A system with two audio tracks can utilize either two independent
sound tracks or stereo sound.
The desktop system used on an IBM PS/2 that allows users to
integrate text, sound, pictures and motion video into multimedia
Visual Authoring Language
A high-level, usually English-like computer programming language
specifically designed to implement computer-based training
(CBT) or interactive multimedia applications. Authoring languages
allow users without formal training in programming to perform
the programming functions of multimedia development.
The person who creates an interactive videodisc or multimedia
program using an authoring language or system. Development
a multimedia or computer program using an authoring language
and/or authoring system. Authoring is a structured approach
involving the development of all of the elements of a multimedia
program or presentation.
In equipment having loop-through or "daisy-chain"
connections, termination is done at the last device on the
chain. Some such devices provide termination automatically
by the fact that there is no cable going out. Thus this is
the last device and termination is provided.
A collection of specialized authoring programs that helps
users without programming training design multimedia programs
in a relatively "easy-to-learn" language or code.
The automatic alignment of the convergence or red, green and
blue color images on a CRT projector. These
systems use the adjustment of green as the reference.
Internet (TCP/IP) terminology for a collection of gateways
(routers) that fall under one administrative entity and cooperate
using a common Interior Gateway Protocol (IGP).
Automatic picture sizing adjustment to compensate for different
display modes, than enabling the display system to center
the picture and fill the screen.
Gain Control (AGC)
A circuit that adjusts signal amplification based on feedback
from its output or from another circuit. Automatic gain can
be applied ahead of almost any circuit that requires specific
levels to operate. As an example, the color decoder needs
to see a particular level of color sub-carrier at its input
in order to display the correct color at the output. There
is a reference burst at the beginning of each horizontal line
of known original amplitude. The AGC circuit looks at the
incoming signal level and applies any gain correction necessary
to make the burst amplitude correct. In the process of doing
that, it also corrects the amplitude of the color information
in the active picture area.
Acronym for Audio Visual Authoring language.
Acronym for Audio Visual Connection.
Picture Level (APL)
The average signal level with respect to blanking during the
active picture time. APL is expressed as a percentage of the
difference between the blanking and reference white levels.
Acronym for American Wire Gauge.