Glossary of Terms
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+ 5.1 AUDIO or AC3:
The Dolby® Digital audio standard selected for DTV. This system consists of six audio channels: Left, Center, Right, Left Rear, Right Rear, and subwoofer. For the time being, only high end HDTV programs will utilize Dolby® Digital audio.
The first system used to broadcast Eight/KAET-TV. Analog television uses a series of radio frequency (RF) waves to transmmit and display pictures and sound. DTV uses data consisting of 1s and 0s to represent that same information.
Analog technology has been in use for the past 50 years to transmit conventional TV signals to consumers. Most current television transmissions are received through analog television sets. Analog signals vary continuously, creating fluctuations in color and brightness.
Imperfections in the DTV signal, known as "glitches" in analog television. The most common artifacts are small black or white blocks in the picture, called "pixilation," or pops and clicks in the audio.
+ ASPECT RATIO:
Televisons comes in two aspect ratios. These ratios are 4:3 and 16:9. The aspect ratio is the comparison of the screen’s width to its height. Traditional analog TV has a 4:3 aspect ratio. This means that a TV screen is 4 inches wide for every 3 inches of height. Many new digital televisions are 16:9, or “widescreen.” The 16:9 aspect ratio more closely approximates the look of movies.
“Letterbox” is the term used when 16:9 content is viewed on a 4:3 screen. In order to display the widescreen content without distortion or missing parts of the picture, the television will place black bars at the top and bottom of the image.
“Pillar box” is the term used when 4:3 content is viewed on a 16:9 screen. In order to display the squarer traditional picture on a widescreen monitor, black bars are placed down the sides of the screen.
“Postage stamp” is the term used when a 4:3 transmission contains widescreen images and its own letterbox bars. When viewed on a a television, the image will appear as a smaller box within your screen.
An acronym for Advanced Television Systems Committee, and the name of the DTV system used by broadcasters in the U.S.
The range of frequencies over which a signal is allocated for transmission. Eight/KAET's analog and digital transmitters are each allocated 6 megahertz (MHz) of bandwith in which to transmit its signal by the FCC.
+ BARN DOOR
A term used in television production to describe the effect that occurs when a 4:3 image is viewed on a 16:9 screen. When this happens, viewers see black bars on the sides of the screen or "barn doors."
The smallest increment of DTV digital information. A bit is a one or a zero. For the purposes of digital television signals, bits are counted in groups of a million each (Megabits, or Mb). To transmit the DTV signal, the transmitter sends out 20 Megabits (20 million bits) per second (Mb/s)
A term describing the amount of bandwith assigned to a channel. Both analog and digital television are considered broadband signals. Broadband is sometimes referred to as "the pipe" or "the highway".
Security card that digital cable ready TV owners must obtain from their cable company in order to view scrambled programming such as premium services.
CATHODE RAY TUBE (CRT) SCREENS:
Traditional color television screens are available for both analog and digital TV. Their resolution and scanning vary from model to model. These screens have a very bright picture but are limited in size and are quite heavy.
+ CLIFF EFFECT:
When approaching the fringes of reception, analog TV pictures begin to degrade by becoming "snowy." With DTV its all or nothing. In an area with a weak digital signal, a relatively small reduction in signal strength may cause the DTV signal to abruptly change from perfect to nothing; hence the name "cliff effect."
Coaxial inputs (sometimes just called “cable”) provide a simple and comon way to transmit video. Now coaxial inputs are mostly used for connecting a TV set to an antenna or cable system.
+ COMPONENT VIDEO:
Also know as Y Pb Pr, this connector splits the video signal into three parts. With two audio connections, this 5 wire solution is the most common way to connect EDTVs to DVD players and most HDTV monitors to their receivers or set-top boxes.
+ COMPOSITE VIDEO:
Also called “RCA” connectors, it is the most common way to connect peripherals and other components. It consists of one yellow connector for video and two audio connectors for “right” and “left.” Composite connectors cannot transmit high definition pictures, so for HDTV, another connector option, such as HDMI or Component Video, must be used.
Without compression, digital TV in the United States would not be possible. This process reduces the amount of data required to represent a video or audio signal. Basically, using complicated mathematical equations you can squeeze more information into the same amount of space without a noticeable difference in the picture quality.
Compression refers to the reduction of the size of digital data files by removing redundant and/or non-critical information ("data" being the elements of video, audio and other "information"). Digital TV in the U.S. would not be possible without compression.
+ COMPUTER INPUT
Some HDTV sets have an input like SVGA or VGA that allows the TV sets to be connected to computers.
The DTV technology that allows Eight/KAET to use leftover bandwith not being used to transmit television programs to transmit data. This data could include transcripts or web links, video, audio, text or graphics. This information could then be decoded by specially equipped computers, set-top boxes, or DTV receivers. DTV's broadband channel allows information to be downloaded about 600 times faster than a personal computer modem.
Digital refers to the circuitry in which data-carrying signals are restricted to one of two voltage levels, corresponding to logic 1 or 0.
+ DIGITAL BROADCAST SATELLITE (DBS):
TV programming delivered via high-powered satellite. Signals are transmitted to a small dish (usually 18 – 24 inches across) and mounted outside.
+ DIGITAL CABLE:
A service provided by many cable providers, digital cable offers viewers more channels. Contrary to many consumers' beliefs, digital cable is not the same as High- Definition Television or digital television; rather digital cable simply offers cable subscribers the options of paying for more services. Digital Monitor: DTV monitors are televisions that can display a digital signal but lack an integrated tuner (unlike an integrated digital set), and thus cannot receive a digital broadcast signal without an additional set-top box.
+ DIGITAL CABLE READY (DCR):
Also referrred to as “plug-and-play,” this is a DTV or other device for digital cable customers that plugs directly into the cable jack and does not require a separate set-top box to view analog and unscrambled digital cable. Used with a CableCARD, it can receive scrambled programming such as premium services.
+ DOLBY® DIGITAL
This is a digital surround sound technology used in movie theaters and upscale home theater systems that enhances audio. Home theater components with this technology work in conjunction with a "5.1-speaker" system (five speakers plus a low-frequency subwoofer) to produce true-to-life audio that draws the listener into the onscreen action.
The process by which a high resolution signal is reduced to a lower resolution for display. Usually, extra lines are simply ignored when drawing the lower resolution image, but sometimes more sophisticated methods are used.
+ DTV (DIGITAL TELEVISION):
The umbrella term used for the new broadcasting system adopted by the FCC in 1996. DTV includes all elements of digital broadcasting, including High and Standard Definition television, datacasting and multicasting. Analog television receives one continuous electronic signal. In contrast, DTV works on the same principle as a computer or a digitally recorded compact disk. It uses binary code, a series of ones and zeros, rather than a continuous signal.
+ DVI DIGITAL VIDEO INTERFACE (DVI):
DVI is a high quality digital connector. Similar to HDMI and sometimes with HDCP. DVI can digitally transmit uncompressed high definition video, preserving perfect picture quality. Unlike HDMI or Firewire, DVI requires a separate audio connection.
+ ELECTRONIC PROGRAMMING GUIDE (EPG):
Electronics Program Guide (EPG) is an interactive list of upcoming TV programming that can be transmitted along with a DTV program. This menu-based screen will help the viewer navigate the channels available in much the same way that small dish satellites do today. The EPG will allow the viewer to display choices in a variety of ways, such as by genre or other category. Ultimately, the EPG will enable the television to "learn" the viewing habits of its user and suggest viewing schedules.
+ ENHANCED TELEVISON:
(Also known as Interactive Television) The term used for certain digital on-air programming (usually educational) that includes additional resources viewers can download. The system will allow viewers to simultaneously watch an enhanced television program while downloading additional video, audio, text and data related to the program. Currently, the system is still based on broadcast technology, so users who wish to interact with the content provider must have a "back channel" i.e. a telephone or computer modem.
Better digital television transmission than SDTV with at least 480 (progressive), in a 16:9 or 4:3 display and Dolby® digital surround sound. 480p is the quality of most progressive scan DVDs and players.
Also called IEEE 1394 or I-link. Firewire is a way to transmit compressed data and video between components on one cable.
+ FLAT PANEL TV:
Flat Panel TVs are very thin, lightweight TVs that are often hung on the wall. Current flat panels use either Liquid Crystal Display (LCD) or plasma screen technology.
The various standards used to broadcast DTV. Currently, there are several formats used to broadcast both standard and high definition programs. You may hear terms like 480i, 720p and 1080i. These are digital formats.
High Definition Content Protection, a technology used to prevent piracy of high quality uncompressed video, primarily over DVI connections.
High Definition Multimedia Interface, a high quality digital connector. Similar to DVI and sometimes with HDCP, HDMI can digitally transmit uncompressed high definition video and audio on the same cable, preserving picture and sound quality.
+ HDTV (HIGH DEFINITION TELEVISION):
This is the best picture and sound quality available on DTV. HDTV uses four times as many lines of picture as analog television and is also broadcast in the wide-screen, 16:9 format. True HDTV also incorporates 5.1 audio. This is far superior than the analog, stereo audio available on current analog sets.
+ HDTV BUILT-IN: (also Integrated HDTV):
HDTV set with the tuner built into the set. It does not need a separate set-top box to receive over-the-air signals.
+ IEEE 1394:
Also called Firewire or I-link, IEEE 1394 is a way to transmit compressed data and video between components on one cable.
Blank bars above and below the image when viewing 16:9 aspect ratio content on a 4:3 screen.
Because DTV allows you to pack more information into the allotted signal using compression, we can transmit multiple channels in the same bandwith instead of just one. Think of the broadcasting bandwith as a multi-lane freeway. You can run a big, flashy, wide-load truck carrying an HDTV program and take up all the lanes, or you can send multiple compact cars down the same freeway, each carrying an SDTV program.
+ MULTI-CHANNEL DIGITAL SOUND:
Feature of DTV that permits numerous streams of sound to be ttansmitted for a given program, providing stereo, surround sound, and even other languages.
+ NATIVE RESOLUTION:
Specific resolution that a television, whether or not integrated, or a monitor, is designed to display. All other resolutions must be either upconverted or downcoverted for display.
A term used for the digital editing and storage of audio, video and other data. Information (like video footage or a completed program) is retrievable and available for use almost immediately, unlike tape based systems, which require time to move the tape to locate the footage or program needed.
NTSC is the acronym that stands for National Television Systems Committee" and the name of the current analog transmission standard used in the U.S., which the committee created in 1953.
+ PILLAR BOX:
Blank bars to the left and right of a image when viewing 4:3 aspect ratio content on a 16:9 screen.
A tiny sample of video information; the"dots" that make up the television picture.
Pixel is actually two words jammed together: Picture and Element. A pixel is a tiny sample of video information, the "little squares" that make up an overall picture.
+ POSTAGE STAMP:
Occurs when an image is both letter and pillar boxed. When viewed on a television, the image will appear as a smaller box within your screen.
+ PROGRAM AND SYSTEM INFORMATION PROTOCOL (PSIP):
A part of the digital signal which sends information to the digital television about Eight/KAET programs. This information is then used to create the Electronic Program Guide the viewer uses to select programming.
Amount of detail that can be seen in a broadcast image. For television, resolution is measured in horizontal lines displayed (commonly 480, 720, or 1080).
+ SET-TOP CONVERTER BOX (STB):
The STB is used to receive and decode the DTV signal and deliver it to a monitor. It also referred to as a converter box. The STB may also be capable of capturing and decoding enhanced television transmissions.
Other types of STBs are used to convert and decode data for analog cable, digital cable and small dish satellite. Some, but not all of these STBs are also capable of decoding DTV.
+ STANDARD DEFINITION TELEVISION (SDTV):
Digital formats that do not achieve the quality of HDTV, but are equal to or superior to an analog signal. SDTV signals may be broadcast in 4:3 or 16:9 formats and may or may not include Dolby® Digital audio.
A broadcast signal transmitted "over the air" to an antenna.
+ TIVO (or REPLAY TV):
Two brand names for a consumer video file server. These units will continually record what you are watching on television, allowing you to immediately replay parts of the program, pause the program, or record for viewing later. It is expected that these units will eventually be incorporated into Set-Top Boxes and are already available in some STBs used for Direct TV.
Process by which a digital, high definition television takes a lower definition picture and converts it into a higher definition picture. This may be done by doubling each line as it is drawn on the screen, or by using advanced algorithms to interpolate the data between each lower resolution line, filling in the missing image.
+ VIDEO DISPLAY UNIT (VDU):
Formerly known as your TV, now called your VDU or your monitor, the device containing the television tube or tubes which display the television picture.
+ VIDEO FILE SERVER:
A unit which uses computer hard drives rather than magnetic tape to record and playback video and audio. Because these units are "non-linear" a program may be broadcast while the end of the program is still being recorded. They are also very useful in editing television programs, since pieces of the programs can be easily moved about.
A term given to picture displays with a wider aspect ratio than NTSC 4:3. Digital HDTV or SDTV is referred to as "16:9 wide screen." Most motion pictures also have a 16:9 wide screen aspect ratio. Most Digital TVs have a screen that is wider than it is tall (if a Digital TV screen is nine inches high, it's 16 inches wide.) When watching a show recorded in the wide screen format on a Digital TV, viewers see more of the movie, while when viewing wide screen format on an analog TV, cropped edges are evident.
+ YAGI ANTENNA:
Type of antenna, generally designed for UHF frequencies, that is ideal for receiving most DTV stations. Ranging in size from several inches to many feet, a yagi antenna is the most common design for roof-top antennas.
Sources include: http://www.dtv.gov