Glossary 163
VGA A type of video signal with a resolution of 640 (horizontal) ^ 480 (vertical) dots that is used by IBM PC/AT-compatible computers.
XGA A type of video signal with a resolution of 1,024 (horizontal) ^ 768 (vertical) dots that is used by IBM PC/AT-compatible
computers.
Aspect Ratio
(Aspect Ratio)
The ratio between an image's length and its height. HDTV images have an aspect ratio of 16:9 and appear elongated. The aspect
ratio for standard images is 4:3.
Interlace A method of image scanning whereby the image data is divided into fine horizontal lines that are displayed in sequence starting
from left to right and then from top to bottom. The even-numbered lines and odd-numbered lines are displayed alternately.
Gateway address
(Gateway Address)
This is a server (router) for communicating across a network (subnet) divided according to subnet masks.
Contrast The relative brightness of the light and dark areas of an image can be increased or decreased to make text and graphics stand out
more clearly, or to make them appear softer. Adjusting this particular property of an image is called Contrast adjustm ent.
Component Video A Video signal which has the lu minance component and col or component separated to provide better image quality.
Refers to images that consist of three independent signals: Y (luminance signal), Pb and Pr (color difference signals).
Composite video Video signals that have the video brightness signals and color signals mixed together. The type of signals commonly used by
household video equipment (NTSC, PAL, and SECAM formats). The carrier signal Y (luminance signal) and chroma (color) signal
that are contained in the color bar are overlapped to form a single signal.
Subnet mask
(Subnet Mask)
This is a numeric al value that defines the n umber of bits used for the network address on a divided network (subnet) from the IP
address.
Sync. The signals output from computers have a specific frequency. If the projector frequency does not match this frequency, the
resulting images are not of a good quality. The process of matching the phases of these signals (the relative position of the crests
and the troughs in the signal) is called Synchronization. If the signals are not synchronized, flickering, blurriness, and horizontal
interference occur.
Tracking The signals output from computers have a specific frequency. If the projector frequency does not match this frequency, the
resulting images are not of a good quality. The process of matching the frequency of these signals (the number of crests in the
signal) is called Tracking. If Tracking is not carried out correctly, wide vertical stripes appear in the signal.
Trap IP Address This is the IP Address for the destination computer used for error notification in SNMP.
Dolby Digital A sound format developed by Dolby Laboratories. Normal stereo is a 2-channel format that uses two speakers. Dolby Digital is a
6- channel (5.1-channel) system which adds to this a center speaker, two rear speakers, and a sub-woofer.
Progressive 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.