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Definitions for the Audio Visual field.

N through Z

Non-Interlaced
Each line of an imaged is scanned during each total vertical (full) screen refresh, this process greatly reduces image flicker, resulting in reduced eyestrain.

NTSC
National Television Standards Committee. Usually refers to the standard for video and broadcasting used in the United States, Canada and several other countries. The NTSC standard is older and produces lower resolution than other television systems used in the world. It is incompatible with other television standards.

OHP
The common abbreviation for overhead projector.

Overhead Projector (OHP)
A device consisting of light source, a glass platform and a focusable lens assembly, designed to project to a screen, images from transparencies. Overhead projectors for LCD panels are particularly bright, and start at about 3000 lumens, or about 2 to 4 times as bright as most older overheads.

Overlay
The ability to superimpose computer generated graphics and/or text on motion or still video.

PAL
Phase Alternate Line. The PAL television system used extensively in Great Britain and western Europe. It is incompatible with other television standards.

Palette
The number of colors available for use in creating an image.

Parallel
A method of transmitting several bits of data simultaneously through a communications channel.

Passive Matrix LCD
The original LCDs, these are controlled by a single processing system, for the whole screen, unlike active and poly-silicate panels, which have discrete circuits for each "pixel". This results in a panel with less color dynamics and lower contrast ratio. A major drawback of passive matrix LCD is they are very slow. With a passive LCD laptop computer, any moving screen object, such as the cursor, may disappear until you stop moving it. Very few projectors still use a passive matrix display.

Peripheral
External devices controlled by the computer, e.g. printer, keyboard, mouse.

Pixel
Short for picture element. The smallest element of a raster display represented as a point with specified color and intensity.

Polysilicon LCD
The latest LCD technology for LCD projectors. Polysilicon is usually 3 separate layers of LCDs, for red, green and blue light. This results in increased color dynamics, with high contrast ratios around 200:1. Poly silicon is ideal for multimedia applications.

Power Lens
Typically a motorized lens that allows adjustment of focus and zoom from a remote control.

Rear Screen Projection
The projector is placed behind a translucent glass or plastic screen, out of sight of the audience. It projects onto the back screen and the audience sees on the front. Some large screen projection monitors use rear screen projection.

Refresh Rate
The number of times the screen image is "painted" or refreshed per second, expressed in Hz.

Resolution
Number of dots or pixels per unit of area. The greater the pixels per unit area the higher the resolution, giving more detail.

Response Time
The reaction time for a pixel to turn on and off. An active-matrix LCD projection panel's response time is fast enough to display full-motion video and rapid mouse cursor movements.

Reverse Image
Reverse image is a feature found on many projectors which flips the image horizontally. Reverse image is needed for rear projection.

RGB
Red, Green, Blue, A video or data signal in which the component color information of a video signal is carried as separate signals. Also used to describe the type of monitor.

Scan Rate
Referring to the horizontal or vertical rates, expressed in Kilo Hertz(kHz).

SCSI
Small Computer Systems Interface, pronounced "scussy". A device independent interface used for a wide range of peripherals.

SECAM
A television standard for video and broadcasting. Used mainly in France and the former East Bloc countries. Higher resolution than NTSC. It is incompatible with other television standards.

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

Short Throw Lens
A lens designed to project the largest possible image a short distance. They are often required for rear projection, where the depth behind the screen is limited.

Source
An input feeding a signal to a projector.

Sun Workstation Resolution
Most Sun workstations use 1152 x 900 as their default resolution.

STN
Super Twist Nematic.

SVGA (Super VGA) Resolution
SVGA refers to a 800 x 600 pixel display, regardless of the number of colors available.

SXGA Resolution
SXGA refers to a monitor resolution of 1280 x 1024 pixel display, regardless of the number of colors available.

S-VHS Input
S-VHS is a standard for transmitting video information. It provides significantly better image quality than composite video.

TFT
Thin Film Transistor. This is a developing technology that attempts to place the controller an LCD panel directly on the surface of the glass.

Touchscreen
A display device that acts as an input device by responding to the touch of the user.

Track Ball
A device used to control movement of an icon (such as a cursor) across an image. Rotating the ball in a direction corresponds directly to the mouse's movements.

Transmitivity
The percent of the light that is transmitted off the stage of the overhead projector that reaches the screen at a given distance. Typically, LCD projection panels are able to use less than 10% of the total light available.

True Color
A term for 24 bit color (16.7 million colors - any combination of 256 shades each of Red, Green, and Blue).

TSTN
Triple Super Twist Nematic. Where three separate LCD plates are combined to form a single panel.

VESA Standard
A set of display specifications agreed upon by the Video Electronics Standards Association. A non-profit group organized to define and improve computer graphics standards.

Video
The capability to project images from a VCR, laser disc, or PC with CD-ROM drive.

Video Standards
A variety of broadcast and video standards, including NTSC, PAL, SECAM. Multiple Video Standards is an important feature if you plan to use your projector in other countries.

Viewing Angle
Maximum angle at which a viewer can clearly see an image projected on a screen.

VGA
Video Graphics Array. 640 x 480 resolution.

VGA Resolution
VGA resolution normally refers to a 640 x 480 pixel display, regardless of the number of colors available.

Window
A portion of the computer screen in which a video image or other information is presented.

Workstation
A desktop computer typically dedicated to a single engineer. Usually a high-end machine.

Workstation Resolutions
Generally a number of different resolutions, higher than 1024 x 768. Most widely used: 1280 x 1024, 1152 x 900 and 1600 x 1200. Some workstations can be set to the lower resolution of 1024 x 768, but are not normally operated there.

WYSIWYG
What You See Is What You Get. This refers to a graphical display mode in which the page on the display screen represents exactly what will appear on the printed page.

XGA Resolution
One of several terms used to describe 1024 x 768 resolution.

Y-Cable
Most computers have only one monitor output. Subsequently, a special cable is necessary to split the monitor signal so it will work simultaneously with both a monitor and a projector.

Zoom Lens
A lens with a variable focal length. This translates to being able to adjust the size of the image on a screen by adjusting the zoom lens, instead of having to move the projector closer or further.

Zoom Lens Ratio
The ratio between the smallest and largest image a lens can projector from a fixed distance.

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