Digital Television Terms Glossary [g-p]
Ghosting
Refers to the effect where multiple overlaid TV images are noticeable
around the edges of objects. This occurs when the antenna picks up
multiple signals in addition to the original signal due to reflection
from objects or other distortions. Also refers to the image left on a
screen as a result of burn-in.
Grayscale
Range of gray at different intensities from completely black to
completely white.
HDMI / HDCP Interface
USB-like connection that can transmit both uncompressed digital audio
and video signals while simultaneously adhering to the High-bandwidth
Digital Content Protection (HDCP) standard.
HDTV
Acronym for "high definition television", the highest of the digital
television standards. HDTV displays pictures either in 720p or 1080i.
HDTV-Ready
Refers to any television that would be capable of receiving high
definition signals, provided that an additional receiver is also
connected. An HDTV-ready television requires an HDTV receiver in order
to receive and decode high definition signals.
HDTV Receiver
Device that receives and decodes high definition signals. An HDTV
receiver is required to be connected to an HDTV-ready TV in order for
the TV to receive high definition signals.
HDTV Tuner
Same as an HDTV receiver.
Horizontal Resolution
Number of vertical lines (or pixels) that can be resolved from one side
of an image to the other. While the vertical resolution of all analog
video sources is the same (480 lines), the horizontal resolution varies
according to the source. Some examples for typical sources: VHS VCRs
(240 lines), analog TV broadcasts (330 lines), non-HDTV digital
satellite TV (up to 380 lines), and DVD players (540 lines). DTV signals
have horizontal resolution that ranges from 640 lines for SDTV to 1,280
lines (for 720p HDTV) or 1,920 lines (for 1080i HDTV). (Definition
properly attributed to CNET.)
Integrated Speaker System
Refers to speakers built into the television. Many plasma and LCD models
do not come with integrated speakers. Therefore, it is important to note
whether this feature is included before purchasing. Otherwise, separate
speakers will need to be purchased.
Interlacing
Refers to scanning method used by the majority of televisions and the
1080i HDTV format. Interlacing involves painting the odd-numbered lines
of a screen in succession, then going back and filling in all the
remaining even-numbered lines. As opposed to progressive scanning in
which all the lines are painted in sequence, interlacing is more prone
to artifacts and is less stable than progressive.
LCD
Refers to liquid crystal display technology, one of the two most popular
technologies behind flat panel televisions (the other being plasma).
Liquid crystal display technology works by blocking light from a high
intensity source in order to display a picture. Liquid crystals are
sandwiched between two glass plates and minor temperature variations are
introduced to particular points causing the crystals to change colors in
predetermined patterns.
LCoS
Refers to "liquid crystal on silicon", a newer form of liquid crystal
technology. Whereas liquid crystal in an LCD screen is sandwiched
between two transparent plates, LCoS involves liquid crystals placed on
silicon, a hoped-for cheaper manufacturing alternative.
Letterbox
Refers to a way that wide-screen images are displayed on a standard 4:3
screen. In letterbox format, the image is bounded by black bars on the
top and bottom to create a widescreen image.
Line-doubler/tripler/multiplier
Technology used to create a higher-quality picture by increasing the
number of lines of resolution displayed.
Lumens
The unit of measure for the light output of a projector.
Mpeg-2
Refers to Moving Picture Experts Group-2, a video-compression scheme
used to condense digital video content for broadcast over thin TV
bandwidths or via the Internet, and to squeeze full-length digital films
onto a DVD.
Native Resolution
Refers to the resolution at which a TV or monitor is designed to display
images without conversion. Image signals higher or lower than a
specified native resolution must be converted to display accurately. For
example, a television with a native resolution of 1080i will need to
upconvert 480p images to 1080i to display properly. CRT TVs can have
multiple resolutions but flat panel TVs can only have one native
resolution.
NTSC
Acronym for National Television Standards Committee, the FCC engineering
group formed in 1940 to develop technical standards for black-and-white
television (NTSC broadcasting began July 1, 1941) and color television
(1953). NTSC developed the video-transmission standard used in the
western hemisphere, Japan, and other Asian countries. NTSC standards are
525 lines of resolution transmitted within a 6MHz channel at 30fps.
OSD
Refers to "on-screen display" program setup. OSD allows one to view and
change settings displayed on the television screen.
Over the Air Broadcast
Refers to any broadcast signal received by the television other than
from subscriber satellite or cable.
PAL
Acronym for Phase Alternating Line, the video-transmission standard
introduced in the early 1960s and used in most European countries except
France and the former Soviet Union. PAL standards specify 625 lines of
resolution at 50fps.
Picture-in-Picture (PIP)
Refers to the ability of newer television models to display two channels
at once. PIPs are usually displayed as a small rectangular screen within
the main TV screen or two images side-by-side.
Pixel
Refers to the smallest points of color on a screen, composed of separate
red, green and blue subpixels that combine to create an image.
Pixel Pitch
Refers to the distance between pixels. The lower the pixel pitch, the
sharper the image.
Plasma
Refers to the display technology in plasma televisions. Each plasma
panel contains thousands of tiny tubes filled with ionized gas that,
when excited by electricity, glow in different colors and intensities to
create an image.
Progressive Scan
Scanning method whereby each row of pixels is sequentially scanned as
opposed to interlaced scanning whereby all odd pixels are scanned, then
all even pixels.
PVR
Same as DVR.
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