24
-Glossary
Appendix.fm7/22/03
Glossary
Complex terms used in this book, or terms not explained in the body of the text, will be briefly explained
here. For further explanation, please consult commercially available reference texts.
Aspect ratio
The ratio between an image's length and its height. Images which have an aspect ratio of
16:9 are called Widescreen. The aspect ratio for standard images is 4:3.
Color Temperature
The temperature of an object which is emitting light. When the colour temperature is high,
colours tend to take on a bluish tinge; when the colour temperature is low, colours tend to
take on a reddish tinge.
Component Video
A type of video signal which has the video brightness and colour signal information
separated, in order to provide better image quality. In high-definition TV (HDTV), it refers
to images which consist of three independent signals: Y (luminance signal), and Pb and Pr
(colour difference signals).
Composite Video
The standard home video signal (NTSC, PAL, SECAM) which has the video brightness and
colour signal information mixed together. Composite video consists of the carrier signal Y
(luminance signal) and the chroma (colour) signal, combined within the colour bar signal.
Contrast
The relative brightness of the light and dark areas of an image can be increased or decreased
in order to make text and graphics stand out, or appear softer. Adjusting this particular
property of an image is called "contrast adjustment".
Cool-down
The process used to cool down a projector lamp that is hot from use. Cool-down happens
automatically when the [Power] button is pressed on the projector or on the remote control
to turn the projector off. Do not unplug the projector power cable whilst it is cooling down.
If cool-down is interrupted, heat from the lamp gets trapped inside the projector, potentially
shortening the life of the lamp and causing projector failure.
Dolby digital
An audio format developed by Dolby Laboratories. Normal stereo is a 2-channel format
which uses two speakers, whereas Dolby Digital is a 6-channel (5.1-channel) system which
adds a centre speaker, two rear speakers and a sub-woofer.
HDTV
An abbreviation for High-Definition Television, it refers to high definition systems which
satisfy the following conditions.
• Vertical resolution of 750p or 1125i or greater
(p=Progressive scanning
g
, i=Interlaced scanning
g
)
• Screen aspect ratio of 16:9
• Dolby digital
g
l audio reception and playback (or output)
Interlaced scanning
Each screen is divided into fine horizontal lines which are displayed in sequence starting
from left to right and then from top to bottom. This method of image scanning, whereby
even numbered lines and odd numbered lines are displayed alternately, is called Interlaced
scanning.
Progressive
scanning
A method of image scanning whereby the image data from a single image is scanned
sequentially from top to bottom to create a single image.
Refresh Rate
The light-emitting element of a display maintains the same luminosity and colour for an
extremely short time. For this reason, the image must be scanned many times per second in
order to refresh the light-emitting element. The number of refresh operations per second is
called the "refresh rate", and is expressed in hertz (Hz).
RGB-Video
A term used to describe a video signal most commonly output to computer monitors. RGB
video is made up of electrical pulses representing the intensities of the three primary colours
of light, red, green and blue. A fourth or fifth pulse carries timing information.
SCART
A 21pin rectangular shaped connector for transmitting audio and video signals between TV,
VTR and AV equipment. RGB, S-Video/Composite video and two audio channels can be
transmitted.
SDTV
An abbreviation for Standard Definition Television. It refers to standard television systems
which do not satisfy the conditions for High-Definition Television.
Security lock
A device consisting of a projector case with a hole in it that a commercially-available theft-
prevention cable can be passed through in order to secure the device to a table or pillar. This
projector is compatible with the Microsaver Security System manufactured by Kensington.
Squeeze mode
The method of compressing 16:9 Widescreen images and recording them on video software
as 4:3 images.
When projecting with Squeeze mode on, the images will return to their original 16:9 format.
USERS_E.BOOK Page 24 Tuesday, July 22, 2003 3:37 PM
