|GLOSSARY OF TERMS
24 bit color - Computer
graphics system where each pixel can have 256 levels of red, 256 levels
of green, and 256 levels of blue simultaneously, allowing each pixel to
be any of over 16+ million colors (256x256x256).
A/B switch - An electronic or
manual switch which selects either the signal from cable A or the
signal from cable B and feeds the signal to a TV, VCR, or other
AC Adapter - Device that connects
to a wall electrical outlet (AC), and sends power to a device to:
charge its batteries, or operate without using battery power.
Adapter - A connector which allows
one type of plug to fit into another type of socket.
Analog - A signal that varies
continuously as opposed to a digital signal made of discrete levels.
Analog circuits can suffer from noise and distortion. Phonograph
records and tapes are examples of analog signals. CDs / Compact Discs
use digital signals.
(A-to-D) converter - A circuit that samples an analog signal
and outputs the information as digital data.
switch or flicker filter - A feature on some scan
converters that processes fine lines in computer graphics so that they
don't flicker when displayed as interlaced video on a TV.
Artifacts - Undesirable elements
or defects in a video picture, such as dots crawling along the edge of
colored graphics, or color rainbows around shirts with stripes or
herringbones. An artifact is some physical disruption of the image.
Aspect Ratio - The shape of a
TV screen expressed as width divided by its height. Common TV screens
have a 4:3 aspect ratio. High Definition HDTV screens have a 16:9
aspect ratio (a wider image).
ATSC - Advanced Television Systems
Committee, a group formed to study DTV and make recommendations to the
AV - AV stands for Audio Video
Bandwidth - The range of signal
frequencies that a piece of audio or video equipment can encode or
decode; the difference between the limiting frequencies of a continuous
frequency band. Video uses higher frequency that audio, thus requires a
BNC - A popular industrial connector
used for video or sync. Sometimes used for RF.
Brightness - In color video, the
characteristics that makes pictures appear to be most intense, created
by luminosity; also the quality of being filled with light.
CATV - An abbreviated term for
Community Antenna Television, now generally regarded as "cable TV".
Chroma - The video signal contains
two pieces that make up what you see on the screen: the black and white
(luma) part, and the color part. Short for chrominance, chroma is the
color component of the video signal.
Coax or Coaxial Cable
- Stiff, round wire about 1/4 inch in diameter, used to carry video,
sync, or RF (antenna) signals. Coaxial cable, sometimes called RF
Cable, is an electrical cable used mostly for transmission of video
signals. Due to its low signal loss, long lengths of this cable can be
used before any signal loss causes a drop in picture quality. The
connectors on each end of the cable are called RF Connectors.
Codec - Abbreviation of Coder-Decoder.
An electronic device or software used to compress and decompress video.
Component Video - Easily
confused with the similar sounding "Composite Video," a Component Video
connection involves a set of 3 cables: 2 cables to handle the color
(aka chrominance) and 1 to handle the brightness (aka luminance).
Component Video cables are color coded (red, green and blue) for easy
identification when hooking up your components. Component connections
are found on most DVD players and HDTV's and on mid- to upper-level AV
receivers. Generally superior quality to S-video, but not quite as good
as DVI or HDMI.
Composite Video - A video
stream that combines red, green, blue, and synchronization signals into
one so that it requires only one connector and/or connection. Composite
video is employed by most television systems (e.g., NTSC, PAL) and
VCRs. Unlike Component video's 3-cable method, Composite video is
a single cable, typically color coded yellow for easy differentiation
from similar looking audio cables. Composite video cables are designed
specifically to handle video signals. Composite video does a capable
job of delivering a good picture via a single cable, but there are
several higher quality choices. Also means color video carried on one
wire with the colors combined (encoded) with the brightness
constituents of the picture.
Compression - To reduce the size
of audio or video data through the use of compression. Also called
encode. The process of electronically processing audio or video
signals so that it requires less storage on a computer hard drive. A
5:1 compression requires more storage space, but has better quality
than a 10:1 compression. Higher compression ratio means a smaller file
size but also less quality.
CRT - Cathode Ray Tube (CRT). The heavy
glass picture tube used in most TVs and computer monitors. These are
quickly being phased out in favor of LCD and Plasma displays.
Digital zoom - An electronic
way of blowing up a picture making it look larger.
- A device which splits and amplifies an audio and/or video source
signal to several audio/video outputs. Used to duplicate one videotape
to any number of VCRs with minimal loss of signal strength..
DRM - (Digital Rights Management) Short
for digital rights management, a system for protecting the copyrights
of data circulated via the Internet or other digital media by enabling
secure distribution and/or disabling illegal distribution of the data.
Typically, a DRM system protects intellectual property by either
encrypting the data so that it can only be accessed by authorized users
or marking the content with a digital watermark or similar method so
that the content can not be freely distributed.
DTV - Digital Television, TV that is
broadcast, recorded, and processed digitally, possibly with extended
definition like HDTV.
DVI - (Digital Video Interface) - DVI
is one of the best methods for delivering video digitally and is
available on most HDTV tuners and HDTV-ready televisions as well as on
many DVD players, mid- to upper-level AV receivers and newer computer
monitors. DVI is an encrypted format so you can't record a signal
delivered via DVI. However, you can use DVI for your TV and an analog
video format (such as component video or S-video) to record to a DVR
(such as Tivo®) or DVD recorder.
DVR - Digital Video Recorder. A VCR or
computer disk recorder that records/plays digits representing audio and
F-Connector - The standard
connector used with coaxial cable and the RF inputs/outputs of most
Flic-Free™ - AITech's
Flic-Free™ filter optimizes the video signal to produce a clear and
stable TV image.
Gigahertz (GHz) - One billion
Hertz (Hz) or one billion cycles per second. Many wireless transmitters
and receivers that send video and wireless computer networking
equipment operate on the 2.4 GHz frequency.
HDCP - (High-bandwidth Digital Content
Protection) A form of digital copy protection developed by Intel
Corporation to protect digital audio and video content as it travels
across HDMI and DVI connections. Pre-2005 HDMI and DVI formats
displayed HD resolutions but without any digital protection. HDMI and
DVI Plasma, LCD TVs, monitors and projectors that do not have HDCP
support (all models pre 2005) will not be able to display HDCP material.
HDMI - (High Definition Multimedia
Interface) - HDMI is the current state-of-the-art in delivering the
highest quality video and audio through a single cable. HDMI can send
high definition video (HDTV) as well as surround sound. Most recent
HDTV television and mid- to upper-end home theater receivers and DVD
players offer HDMI connections. HDMI is also compatible with most DVI
connections for video so if you have, say a DVD player with DVI output
and a plasma TV with HDMI input, you can use an HDMI-to-DVI cable to
connect them, although you will need a separate connection for the
audio, such as optical digital or coaxial digital. HDMI is an encrypted
format so you can't record a signal delivered via HDMI. However, you
can use HDMI for your TV and an analog video format (such as component
video or S-video) to record to a DVR (such as Tivo®) or DVD recorder.
HDTV - (High-Definition Television) -
Method of displaying sharper, wider TV pictures than the present NTSC
system. Pictures are 16:9 aspect ratio, composed of 1,125 scanning
lines, each line having 1,920 pixels.
- The number of vertical black and white lines that can be defined, as
measured along a horizontal line.
IC - Integrated Circuit
Interlace - The manner in which a
television picture is composed, scanning alternate lines to produce one
field, approximately every 1/60 of a second in NTSC. Two fields
comprise one television frame resulting in the NTSC television frame
rate of approximately 30 fps.
Interlaced - In a television
display, interlaced scan refers to the process of re-assembling a
picture from a series of video signals. The "standard" NTSC system uses
525 scanning lines to create a picture (frame). The frame/picture is
made up of two fields: The first field has 262.5 odd lines (1,3,5...)
and the second field has 262.5 even lines (2,4,6...). The odd lines are
scanned (drawn on the screen) in 1/60th of a second, and the even lines
follow in the next 1/60th of a second. This presents an entire
frame/picture of 525 lines in 1/30th of a second. Why did the founding
fathers of video decide to go with an interlaced system? It has to do
with frame rate. A large TV screen that was updated at 30 frames per
second would flicker, meaning that the image would begin to fade away
before the next one was drawn on the screen. By using two fields, each
containing one-half of the information that makes up the frame and each
field being drawn on the screen consecutively, the field update rate is
60 fields per second. At this update rate, the eye blends everything
together into a smooth, continuous motion. Analog NTSC video uses
interlaced scanning, as do several digital television formats. Formats
that include an "i" (1080i, 480i) use interlaced scanning. See also
IR - Abbreviated as IR, infrared is a
wave of light that in the area beyond the visible part of the color
spectrum. Wireless remote controls for TVs and other electronic devices
use IR to send commands from the remote to the TV.
Jitter - Short-term variations in the
characteristics (such as frequency, amplitude, etc.) of a signal.
LCD - A liquid crystal display (LCD) is
a thin, flat display device made up of any number of color or
monochrome pixels arrayed in front of a light source or reflector.
Line doubler - Device that
doubles the scan lines that makes a picture, essentially placing lines
between lines, improving the look of video when shown on computer-like
devices such as computer projectors.
Luminance - The term is used to
denote the brightness or black-and-white picture of a video image.
Mini phono jacks - Used on
devices like mp3 players and computer sound cards. Computer speakers
and computer sound cards also use these audio jacks. They are sometimes
called mini-phono plugs or 3.5mm jacks
Macrovision - An anti-copy
signal recorded on a video tape to make it playable but not copyable.
Monitor - A video display. A monitor
is like a TV except it lacks the ability to tune in channels. A monitor
may or may not have a sound amplifier and speaker.
Monochrome - Black and white
video. A video signal that represents the brightness values (luminance)
in the picture, but not the color values (chrominance).
MPEG - The term refers to the family of
digital video compression standards and file formats developed by the
Moving Picture Experts Group. MP3, MPEG-2 and MPEG-4 are common forms
of MPEG compression.
Multimedia - Audio, video, text,
graphics, and other information delivered by computer.
Noise - Unwanted disturbance within an
electronic system. Interference present in a video picture.
Non-interlaced - This is a
method of scanning out a video display that is the total opposite of
interlaced. All of the lines in the frame are scanned out sequentially,
one right after the other. The term field does not apply in a
noninterlaced system. Another term for a noninterlaced system is
NTSC - A TV Standard. National
Television Standards Committee. A group of businesses and engineers
originally created to decide on early standards for color and
black-and-white televisions in the U.S.. The NTSC system is also used
in Japan. Other television standards around the world include PAL (most
of Europe) and SECAM (France, parts of Africa and Russia).
Overscan - A technique used in
consumer display products that extends the deflection of a CRT's
electron beam beyond the physical boundaries of the screen to ensure
that images will always fill the display area. (A TV picture blown up
too big on the screen, causing the edges of the picture to be cut off
and hidden from view) When converting computer screen to
overscan, graphics and text at the edges of the image may be
lost. See also underscan.
PAL - A TV Standard. Phase Alternate
Line is the 625-line color video system currently used in most of
Western Europe, England, Australia, and South Africa. Incompatible with
the U.S. NTSC system.
PCI - Peripheral Component Interconnect,
a very fast pathway for data traveling from one board to another in the
computer. PCI video cards require little configuration (plug-and-play)
in order to work.
Pixel - Short for Picture Element, a
pixel is a single point in a graphic image. Graphics monitors display
pictures by dividing the display screen into thousands (or millions) of
pixels, arranged in rows and columns. The pixels are so close together
that they appear connected.
Plasma Display - A plasma
display panel (PDP) is a type of flat panel display now commonly used
for large TV displays (typically above 32"). Many tiny cells located
between two panels of glass hold an inert mixture of noble gases (neon
and xenon). The gas in the cells is electrically turned into a plasma
which then excites phosphors to emit light. It is often used in the
home environment and is becoming increasingly popular in modern
Power Supply / Power Adapter
- Circuit in electronic equipment which converts household electricity
to the kind of power (correct voltage and frequency) the equipment
needs in order to run.
Progressive scan - Some
digital television broadcast formats (1080p, 720p, 480p), and some
higher-end DVD players, use a type of video signal known as progressive
scan. Instead of splitting each video frame into two sequential fields
like standard interlaced NTSC video, progressive-scan video displays
the entire frame in a single sweep. So, where standard NTSC video
displays 30 frames (60 fields) per second, progressive scan displays 60
full frames per second. Displaying progressive-scan video
requires more bandwidth (there's twice as much vertical information)
and a faster horizontal scan frequency than interlaced video.
Progressive-scan picture quality is more film-like, with more fine
detail and less flicker. For progressive-scan viewing, you'll need a TV
PS/2 - The PS/2 connector is used for
connecting a keyboard and a mouse to a PC compatible computer system.
interference / RF interference - Typically experienced as
"snow" in a TV screen or "pops" in your speakers, there are numerous
sources of radio interference. Some sources are nearby like CB or Ham
radios, or cell phones. Other sources can be far away like radio
stations, microwave towers and the like.
RCA Connector or Phono Plug -
Small connector used to carry analog audio signals and, in home video
equipment, video signals and sometimes RF signals. While there are
higher quality types of audio connections available, older devices
often only offer RCA jacks.
Refresh Rate - The refresh rate
(most commonly the "vertical refresh rate", "vertical scan rate" for
CRTs) is the number of times in a second that display hardware draws
the data it is being given.
Resolution - The clarity or
sharpness of the picture. Resolution is most often stated in the number
of total lines or pixels that make up an image.
RF coaxial - Also known as "75 ohm input" or simply
"coaxial input," this is the basic connector for hooking up antennas,
cable boxes, VCRs and TVs. This connector carries both video and audio
(though only stereo, not surround sound).
RF Modulator - Electronic device which combines audio and
video signals, coding them into RF, a TV channel number.
RGB - Red, Green, and Blue are the three additive colors
used for TV and computer monitor signals. .
Saturation - The strength or
amount of a certain color present in a television picture; saturation
is expressed as the purity of the color.
Scaling - Scaling is the act of
changing the effective resolution of the image. For example, let's take
a TV size resolution of 640x480 and display that image as a smaller
picture on the same screen, so that multiple pictures can be shown
simultaneously. We could scale the original image down to a resolution
of 320x240, which is 1/4 of the original size. Now, four pictures can
be shown at the same time. That was an example of "scaling down."
Scaling up is what occurs when a snapshot is enlarged into an 8"x 10"
glossy. There are many different methods for image scaling, and some "
look" better than others. In general, though, the better the algorithm
"looks," the harder or more expensive it is to implement.
Scan Converter - Electronic
device that changes the signals that a computer sends to its monitor,
into video signals that can be displayed on a TV monitor or recorded on
SCART - This is a 21-pin connector
supported by many consumer audio/video components in Europe. It allows
mono or stereo audio, composite video, S-video, and RGB video to be
transmitted between equipment.
SDTV - Standard Definition Television,
digitally broadcast TV signals with about the same sharpness and screen
shape as today's NTSC television.
SECAM - A TV Standard. Sequential
Color And Memory---a video standard used in much of Asia, incompatible
with our NTSC system.
S-Video - Separated Video, also
called Y/C video. A type of video signal. S-Video transmits luminance
and color portions separately, using multiple wires, thus avoiding the
color encoding process and its inevitable loss of picture quality. The
format uses a 4-pin din cable to carry the separated signals,
chrominance and luminance, versus the composite type that combines the
signal over one wire. Virtually all DVD players, most satellite
receivers and AV receivers and most newer TVs have S-video connections.
In the "Good-Better-Best" scenario of choices, S-video is somewhere
between 'Good' and 'Better.' Utilizing a round, 4-pin connector,
S-video provides better picture quality than RF Coaxial or Composite
video, but not as good as Component video or the two digital formats,
DVI and HDMI.
Scaling - Scaling is the act of changing the effective
resolution of the image. For example, let's take a TV size resolution
of 640x480 and display that image as a smaller picture on the same
screen, so that multiple pictures can be shown simultaneously. We could
scale the original image down to a resolution of 320x240, which is 1/4
of the original size. Now, four pictures can be shown at the same time.
That was an example of "scaling down." Scaling up is what occurs when a
snapshot is enlarged into an 8"x 10" glossy. There are many different
methods for image scaling, and some " look" better than others. In
general, though, the better the algorithm "looks," the harder or more
expensive it is to implement.
Streaming Media - Internet
video and/or audio clips that can play directly over the Internet,
without needing to be downloaded first onto a computer. Used to view
and hear broadcasts, and to interactively play and seek in stored clips.
TV Standard - Set of technical
specifications describing how a TV picture is made. In the USA, the FCC
(Federal Communications Committee) ordained the NTSC (National
Television Standards Committee) standard. In Europe, they use a
different, incompatible standard, PAL.
UL - UL stands for Underwriters
Laboratories Inc., an independent, non-profit, product safety testing
and certification organization in the United States. Since 1894, UL has
been one of the leaders in testing products for public safety. If a
product is UL listed, it has been tested and approved by the
Underscan - A technique generally
used by some TV and video systems as a way of ensuring that the
complete image is always visible within a display area. TV picture
which is smaller than the screen, showing the black edges of the
picture on the screen. Most televisions use overscanning.
Underscanning modifies the video timing so that the entire video signal
appears in a rectangle centered on the television screen with a black
border. The resolutions for square-pixel underscan and overscan images
NTSC overscan: 640 x 480
NTSC underscan: 512 x 384
PAL overscan: 768 x 576
PAL underscan: 640 x 480
USB - (Universal Serial Bus) ports are
on virtually every PC and Mac made in the past 5 years. A USB
connection is often used to connect flash drives, digital cameras, mp3
players and other portable A/V devices to a computer. There are a few
types of USB connectors. The USB Type A connector plugs into the USB
port on your computer. The USB Type B connector plugs into a peripheral
device (such as a monitor or printer). Compact devices like cameras and
mp3 players typically have smaller USB jacks called a mini USB. All USB
cables have a Type A connector on one end (for the computer) and either
a Type B or mini USB connector on the other end.
VGA - Also sometimes referred to as RGB
(D-sub 15-pin), VGA cables are used to connect a computer to a
projector, computer monitor, scan converter, plasma TV, LCD TV or other
digital flat panel TV's. VGA provides high quality analog video by
separating the video signal into 3 parts which allows for exceptionally
clear and bright images.
VGA Monitor - A monitor capable of displaying a VGA signal. Can be
either CRT, LCD, Plasma.
Video Card or Video Adapter - Sometimes also called a VGA Card, this is
the device inside a laptop or desktop computer that the computer
monitor connects to.
Video signal - An electrical
signal that includes all of the information present in the television
picture together with the necessary synchronizing signals.
VOD - (Video On Demand) High speed
Internet connection permitting users to download video (i.e., movies),
playing it in real time on their TVs.
VSPro™ - AITech's patented video
signal processing technology, which is used in the AITech's scan
conversion products. VSPro is a high-speed, digital signal processing
technology. It is implemented in AITech's single chip scan converter
products, such as the AIT2138 and AIT1168.
WLAN - (Wireless LAN) A wireless LAN or
WLAN is a wireless local area network, which is the linking of two or
more computers without using wires.
Y/C Video - See S-Video
YPbPr - Analog video signal carried by
component video cable in consumer electronics. Note that the green
cable carries Y, the blue cable carries Pb and the red cable carries Pr.