54
Glossary
Following is an explanation of some of the terms used in this guide which may be unfamiliar or which
were not explained in the manual itself. Further information can be obtained by referring to other
commercially-available publications.
Aspect
The ratio between an image's length and its height.
HDTV images have an aspect of 16:9 and appear
elongated. The aspect for standard images is 4:3.
Component video
Video signals which have the video brightness signals
and color signals 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 (color difference signals).
Composite video
Video signals which 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).
Video signals which consist of a carrier signal Y
(luminance signal) within the color bar signal, and a
chroma or color signal (CbCr).
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 more clearly, or to make them
appear softer.
Cool-down
This is the process by which the projector's lamp is
cooled down after it has become hot through use. It is
carried out automatically when the [Power] button on
either the remote control or the projector's control panel
has been pressed to turn off the projector. Do not turn off
the main power switch while cool-down is in progress,
otherwise the cool-down process will not work properly.
If the cool-down period is not allowed to finish normally,
the projector's lamp and internal components will remain
at high temperatures, and this may shorten the useful life
of the lamp or cause problems with the operation of the
projector. The projector takes about 30 seconds to cool
down. The actual time will vary depending on the
external air temperature.
HDMI
An abbreviation for High Definition Multimedia
Interface, and refers to a standard for digital transmission
of high-definition images and multi-channel audio
signals.
HDMI is a standard that is targeted towards household
digital equipment and computers that allows digital
signals to be transmitted in their original high quality
without compression, and it also includes a digital signal
encryption function.
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 , i = interlaced )
• Screen aspect of 16:9
• Dolby Digital audio reception and playback (or output)
Interlace
A method of image scanning whereby the signal
bandwidth used is approximately half that required for
sequential scanning when images with the same still
picture resolution are broadcast.
NTSC
An abbreviation for National Television Standards
Committee, and a format for ground-based analogue
colour television broadcasts. This format is used in Japan,
North America and Central and South America.
PAL
An abbreviation for Phase Alternation by Line, and a
format for ground-based analogue colour television
broadcasts. This format is used in Western European
countries except France, and also in Asian countries such
as China and in Africa.
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.
Refresh rate
The light-emitting element of a display maintains the
same luminosity and color for an extremely short time.
Because of this, 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).
S-Video
A video signal which has the luminance component and
color component separated in order to provide better
image quality.
It refers to images which consist of two independent
signals: Y (luminance signal), and C (color signal).
SDTV
An abbreviation for Standard Definition Television. It
refers to standard television systems which do not satisfy
the conditions for HDTV.
SECAM
An abbreviation for Sequential Couleur A Memoire, and
a format for ground-based analogue colour television
broadcasts. This format is used in France, Eastern Europe
and the former Soviet Union, the Middle East and Africa.
