! HDTV Glossary !

0-9 | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z


3:2 Pull Down
3:2 pull down is a process by which manufacturers add six frames to film original 24-frames-per-second format so that it can work within the NTSC standard, which is 30 fps. If this conversion was not done, the movie would be in fast motion and the sound would be sped up.

4:3
4:3 is an aspect ratio of traditional squarish National Television Systems Committee (NTSC) TV screens; it stands for four units of width for every three units of height. It also translates to a 1.33:1 aspect ratio which was the norm for movies prior to 1950. Also see: DVD Pictures

16:9
16:9 is an aspect ratio of widescreen DTV formats used in all HDTV (High Definition TV) and some SDTV (Standard Definition TV); it stands for 16 arbitrary units of width for every 9 arbitrary units of height. It also translates to 1.78:1 aspect ratio that is very close to the most popular widescreen movie aspect ratio of 1.85:1. Also see: DVD Pictures

24P
Terminology for 24 full frames per second digital video progressively captured and or displayed. In most cases it refers to the HD picture format of 1920×1080, though it is also used with 1280×720 images as well. Often used to loosely describe a capture system that operates at 23.976P as well.

480p
480p means that the resolution of the picture is 480 pixels high. The “p” stands for progressive scanning. The ATSC spec allows these variations of 480p broadcast video:

Pixels
Wide
Pixels High A/R Frame Rate

704

480

16:9

24

704

480

16:9

30

704

480

16:9

60

704

480

4:3

24

704

480

4:3

30

704

480

4:3

60

640

480

4:3

24

640

480

4:3

30

640

480

4:3

60

The red entries are what is most commonly used in 480p DTV broadcasts.

720p
720p means that the resolution of the picture is 1,280 pixels wide by 720 pixels high and p stands for progressive scanning. Progressive scanning offers a smoother picture as 720 horizontal lines are scanned progressively or in succession in a vertical frame that is repeated 60 times a second in US consumer HDTVs. The broadcast specification for 720p allows for 720p at 24fps, 720p at 30fps and 720p at 60fps. Most stations that broadcast in 720p use the 720p at 60fps selection. This includes ABC, FOX, My Network TV and ESPN on cable/satellite.

1080i
1080i means that the resolution of the picture is 1920 pixels wide by 1080 pixels high and i stands for interlaced scanning. Interlaced scanning is based on the principle that the screen is scanned with two fields to make up the entire frame. Field 1 shows all of the odd lines of screen and then field 2 shows all the even lines. Each field is completed in 1/60th second for a final frame rate of 30 frames per second. All HDTV stations other than those listed for 720p use this HDTV broadcast format. This includes, but not limited to, CBS, NBC, PBS, CW, and most cable/satellite HD channels.

1080p
1080p means that the resolution of the picture is 1,920 vertical pixels by 1,080 horizontal pixels and p stands for progressive scanning. This format works on the same principle as 720p; the only difference is that in this type there are more pixels thus resolution is better. The broadcast specification for 1080p allows for 1080p at 24 fps and 1080p at 30 fps. Currently there are not any broadcasters using either of these formats, however both Blu-ray and HD DVD high definition movie discs use the 1080p at 24 fps as the storage format. Some players will even output 1080p at 24 fps.


AC-3
The 5.1-channel sound system specified in the Standard for Digital-HDTV. Also known as “Dolby Digital,” AC-3 delivers CD-quality digital audio and provides five full-bandwidth channels for front left, front right, center, surround left and surround right speakers, plus an LFE (low-frequency effect) subwoofer, for a total of 5.1 channels.

A/D Converter
Analog to digital conversion. Used at transmission end of broadcast when the source is analog, such as analog cameras. Newer digital display technologies will use an A/D converter when viewing the composite video, s-video, component and VGA inputs to convert the analog signal received to the digital data required by the display. Even the newer CRT displays that use an all digital chassis will also use an A/D converter on these inputs to convert the signals for the digital processors.

Advanced Television Systems Committee (ATSC)
Advanced Television Systems Committee is responsible for establishing and developing digital television standards, as well as all 18 formats of Digital TV. For a table of the formats see the table in: HDTV Introduction.

Addressable Resolution
The highest resolution signal that a TV or monitor can accept. It is important to note that while a particular device (Digital-HDTV) is able to receive the resolution, it may not be capable of displaying it. An example would be the popular plasma displays that have a pixel resolution of 1024×768 or 1366×768. While these sets will receive a signal of 1920×1080 they are not capable of displaying the full resolution. The received images is scaled to the addressable resolution of the display. The addressable resolution is more commonly referred to as the native resolution of a display.

Analog TV
Analog technology has been in use for the past 50 years to transmit conventional TV signals to consumers. “Standard” television broadcasts in analog TV. Analog signals vary continuously, creating fluctuations in color and brightness. The current date for the broadcast cutoff for analog TV is Feb. 2009. Note this does not affect cable television systems.

Anamorphic video
Video images that have been “squeezed” to fit a video frame when stored on DVD to avoid the necessity of storing the black bars top and bottom on letterboxed movies. These images must be expanded (un-squeezed) by the display device or player. An increasing number of TVs employ either a screen with 16:9 aspect ratio, or some type of “enhanced-for-widescreen” viewing mode, so that anamorphic and other widescreen material can be viewed in its proper proportions. When anamorphic video is displayed on a typical TV with 4:3 screen size, the images will appear unnaturally tall and narrow. For more information see: Anamorphic DVD

Artifacts
Artifacts are defined as unwanted visible effects in the picture caused by disturbances and errors in the video transmission or digital processing. Artifacts include edge crawl or dot crawlor hanging dots in analog pictures, and pixelation, contouring or blockiness in digital pictures. For more detail of artifacts that are commonly found with HDTV see: HDTV Artifacts

Aspect ratio
Aspect ratio is ratio of width to height of a TV screen. It may be either traditional squarish 4:3 ratio of the National Television Systems Committee (NTSC) TV screen or 16:9 ratio of widescreen DTV formats for all HDTV (High Definition) and some SDTV (Standard Definition). With TV screens the aspect ratio is noted as shown, but movie aspect ratios will be 1.33:1, 1.85:1, 2.76:1 among others. For more detail see: DVD Pictures

ATSC
An acronym for Advanced Television Systems Committee, which is responsible for developing and establishing Digital-HDTV Standards; and the name of the DTV system used by broadcasters in the U.S. For a table of the ATSC formats see the table in: HDTV Introduction.

Bandwidth
Bandwidth, in general, means amount of information that can be carried in a given time period (usually a second). More exactly, it is a range of frequencies used for transmitting picture and sound information from transmitter to your TV. Federal Communications Commission (FCC) has allocated 6 MHz for TV broadcasters for each channel. This translates to a bit rate of 19.4 Mbps.

Barn Doors
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.” This is also commonly called by the term “pillarboxing.”

Bit Rate
Bit rate is measured as “bits per second” (bps) and refers to the rate at which the data is transmitted. For Digital TV, the maximum possible bit rate within the bandwidth is 19.4 Mbps while SDTV has a lower bit rate. The higher the bit rate, the more data is processed which usually results to higher picture resolution or better sound quality. When the bit rate is less that what is required, the result will be the macroblocking artifact that shows up often with fast motion.

Blu-ray Disc
Blu-ray is a blue laser disc system developed by primarily Sony that can hold up to 25GB on a single-layer disc and 50GB on a dual-layer disc making it suitable for HD movies. For more information see: www.blu-ray.com See also HD DVD Disc for a competing technology.

Burn-in
Burn-in is the result of a static image or pattern appearing so regularly on a screen that it ages the phosphors and remains as a ghost image. Not to be confused with image retention, which is temporary, burn-in is perminate damage to the phosphors. This only occurs on phosphor based TVs like CRT and plasma TVs.

Codec
Codec is a short term for Coder-decoder. This device is used to convert analog video and audio signals into digital format, and vice verse, it can also convert received digital signals into an analog format. Common codecs use in TV compression are mpeg2 and mpeg4.

Component Video Connection
The output of a video device (such as a DTV set-top box), or the input of a DTV receiver or monitor consisting of three primary color signals: red, green, and blue that together convey all necessary picture information. With current consumer video products, the three component signals have been translated into luminance (Y) and two color difference signals (Pb, Pr), each on a separate wire. The sync signals are combined with the (Y) signal. Many people think the signals are red, blue and green, but they are not directly. The Y signal (on the green wire) basically carries the black and white picture information plus the video sync signals. If you unplug the red and blue connections, you will still have a black and white picture. Component video connections will carry up to HD signals 720p and 1080i.

Composite Video
An analog, encoded video signal that includes vertical and horizontal synchronizing information. Since both luminance (brightness) and chrominance (color) signals are encoded together, only a single connection wire is needed. A composite video jack is usually a single RCA-type colored yellow. Composite video connections will carry 480i SD signals.

Compression
Compression allows the delivery of more programs in a single channel. It is a mathimatic manipulation of digital data that reduces and removes redundant and/or non-critical information in the digital picture and sound without noticeably degrading picture quality. One of the compression methods is called MPEG-2.

Computer Input
Some HDTV sets have a PC input like VGA that allows the TV sets to be connected to computers. Also TV sets with DVI and HDMI inputs may be connected to a computer when so equipped. For more information see: Hooking Up A PC to A HDTV

Contrast Ratio
Measures the difference between the brightest whites and the darkest blacks a display can show. The higher the contrast ratio, the greater the ability of a display to show subtle color details and tolerate ambient room light. Contrast ratio is an important spec for all types of TV display, but especially for front projectors.

Color Depth
This refers to the number of unique colors a given system can reproduce or convey. In the digital realm it will define the number of bits used to define each pixel. For example, 24 bit systems can define 16.7 million unique colors and the new HDMI 1.3 specification allows for 30, 36 and 48 bit color depth allowing billions of unique colors. Theoretically this will allow for improved contrast ratios and better color transitions when displays are also capable of the increased color depth.

CRT (Cathode-Ray Tube)
A CRT (”picture tube”) is a specialized vacuum tube in which images are created when an electron beam scans back and forth across the back side of a phosphor-coated screen. Each time the beam makes a pass across the screen, it lights up a horizontal line of phosphor dots on the inside of the glass tube. By rapidly drawing hundreds of these lines from the top to the bottom of the screen, images are created.

D*
An abbreviation for Directv.

D/A
Conversion of digital to analog signals. The device is also referred to as DAC (D/A converter). In order for CRT television technology to display digitally transmitted TV data, the data must be decoded first and then converted back to an analog signal. The newer all digital chassis CRTs will process all video data digitally and use a D/A converter to convert the resulting digital data to analog for output to the CRT.

Datacasting
Also known as “enhanced TV.” Datacasting is the act of providing enhanced options offered with some digital programming to provide additional program material or non-program related resources. This allows viewers the ability to download data (video, audio, text, graphics, maps, services, etc.) to specially equipped computers, cache boxes, set-top boxes, or DTV receivers.

Decoder
See “codec.” A device or program that translates encoded data into its original format (i.e., it decodes the data.) There are two types of decoders, hardware based and software based. The software based decoders are normally used in computers to decode digital data so that many different codecs can be handled. While this gives unlimited flexibility, the problem could be the computer processor may not be fast enough to keep up with the required framerate and skipping or stuttering can result. Hardware decoders will have a dedicated processor to accomplish the decoding which is usually located on the computer’s video card. They can either decode a fixed set of codecs or in some cases it is possible to reprogram with new codecs. The advantage of the hardware decoder is it is independent of the base computer speed.

Deinterlacing
The process of converting an interlaced-scan video signal (where each frame is split into two sequential fields) to a progressive-scan signal (where each frame remains whole). De-interlacers are found in digital TVs and progressive-scan DVD players. More advanced de-interlacers include a feature called 3-2 pulldown processing. For TVs, de-interlacing is often referred to as “line-doubling” or “upconversion.”

Digital *
Digital refers to the circuitry in which data-carrying signals are restricted to one of two voltage levels, corresponding to logic 1 or 0. By combining many of these single 0 or 1 signals (called a bit) many bit patterns can be made to represent the original picture or sound.

Digital Cable
A service provided by many cable providers. By converting video and sound to digital data digital cable offers viewers more channels because once digital the program can be compressed with an encoder. The resulting digital data will require a lot less cable space so the channels can be placed closer together. Both standard definition and high definition channels can exist on digital cable. The transmission method for cable is called QAM and to receive the programming you need a QAM tuner as opposed to a NTSC (analog) or ATSC (OTA digital) tuner. The QAM tuner can be built into many TVs or in a separate cable set top box or DVR.

Digital Television (DTV)
Digital TV is the umbrella term encompassing High-definition Television and several other applications, including Standard Definition Television, datacasting, multicasting and interactivity. OTA digital television actually encompasses 18 different formats from 480i to 1080i. For more information see the information in HDTV Introduction.

Digital Tuner
A digital tuner serves as the decoder required to receive and display digital broadcasts. It can be included inside TV sets, via a set-top box or on a computer card. The ATSC digital tuners are used to receive OTA digital broadcasts, but QAM cable tuners and the tuners in satellite receivers are also digital tuners, they just use different data formats.

Direct-view TV
The conventional and most common type of TV, which uses a single large (up to 40″) CRT to display images.

DLP (digital light processor)
A proprietary electro-mechanical device invented by Texas Instruments that reflects light on a pixel-by-pixel basis to create a projected image. The key components of a DLP are the digital micromirror device, which actually stores image information and reflects light with thousands of 16×16-micron mirrors based on that information, a scan converter that decodes multiple signal sources into progressive red, green and blue information and an RGB color filter wheel. For more information see: www.dlp.com

Dolby Digital (Dolby AC-3)
Dolby Digital, also called Digital 5.1 or AC-3, is a five-channel surround sound system which delivers CD-quality digital audio and provides five channels of full frequency for front left, front right, center, surround left and surround right speakers, plus one channel for LFE (low frequency effect) subwoofer. It is the official audio standard for Digital TV and HDTV. It is the successor to Pro Logic surround. For more see: Let’s Talk Surround

Downconvert
A term used to describe the format conversion from a higher resolution input signal number to a lower display number, such as 1080i input to 480i display. Some HDTV tuners are able to downconvert digital HDTV signals for display on a regular analog TV.

DTS
Digital Theater Systems sound. Discrete 5.1 channel surround system similar but not the same as Dolby Digital. Dolby Digital is the DTV standard, but DTS competes with it on DVD and in the movie theaters.

DTV (Digital Television)
DTV stands for Digital Television. It refers to all digital television formats and standards established by the Advanced Television Systems Committee (ATSC). Two basic DTV standards are HDTV (high-definition television) and SDTV (standard-definition television) and for more information see HDTV Introduction. Many times DTV is also used to shorten Directv, but the more often used abbreviation for Directv is D*.

DVI (Digital Visual Interface)
DVI is a standard that provides a high-bandwidth, low-cost digital interface between a video source and a display device. It is capable of carrying uncompressed unprotected high resolution video transfers of HDTV signals, and supports real-time complex graphics displays and user interfaces found in program guides and other interactive features for high definition television.

DVI w/HDCP (Digital Visual Interface with High Density Copy Protection)
This is the same as above adding high-density digital copy protection, primarily for the secure transfer of high-resolution video content.

E*
An abbreviation for Echostar who offers Dish Network. Thus E* is also used for shorthand of Dish Network.

EDTV (Enhanced-Definition Television)
EDTV stands for Enhanced Definition Television. The picture quality of EDTV is superior to that of standard analog TV (480i) but not as good as HDTV (1080i or 720p). EDTV displays the picture at a resolution of 852×480 (480p) lines in either 4:3 or 16:9 aspect ratios and it includes Dolby Digital sound system. For more information see: HDTV Introduction.

EPG
EPG stands for electronic program guide. It is a system displaying channels and program data on-screen for an extended time period (typically 36 hours or more).


Frequency
The number of times per second that a signal fluctuates. The international unit for frequency is the hertz (Hz). One thousand hertz equals 1 KHz (kilohertz). One million hertz equals 1 MHz (megahertz). One billion hertz equals 1 GHz (gigahertz). Television is broadcast in frequencies ranging from 54 MHz to 216 MHz (VHF) and 470 MHz to 806 MHz (UHF).

Flat-panel TV
Flat-panel TV typically displays picture using gas plasma, SED or LCD technology and is only a few inches thick. The SED displays have not yet been released.

Frame rate
The rate at which frames are displayed. The frame rate for movies is 24 frames per second (24 fps). In regular NTSC video, the frame rate is 30 fps. The frame rate of a progressive-scan format display is twice that of an interlaced-scan format it’s at 60 fps although the broadcast standard will allow 24, 30 and 60 fps depending on the format selected by the broadcaster. For more information see: HDTV Introduction.

Front-projection TV
Front-projection TV comprises 2 parts a separate front projector (usually placed on a table or ceiling-mounted) and a reflective screen (or simply a wall). The projector is placed at one end of the room, the screen is at the other end, and the speakers may be placed wherever they will provide you good sound experience. The picture can be rather large but remember the larger the picture, the more visible the pixels or scan lines and the darker the image.


Gain
Measures the light-reflecting ability of a projection screen. The higher the number, the greater the amount of light reflected back to the viewer(s).

Generation Loss
This refers to video degradation caused by successive recordings (dubs of other dubs) from the master source. This is overcome by digital recording.

Ghosting
Ghosting means multiple overlaid TV images or ghosts which you can notice around the objects while watching TV. Ghosting is caused by the broadcast signal traveling to your TV through various obstacles, for example hills or tall buildings, and your antenna picks up the original TV signal along with signals reflected by the obstacles. If the ghosting is changing rather than static, it may be caused by the signal reflected by flexible objects, for example trees or airplanes. That definition applies to analog reception, but there is another method of seeing ghosting. Ghosting can also occur due to impedance mismatches in analog cabling because of reflected signals. The most common time this will occur is when very long runs of cable are made or should two TVs have their analog video connected through a simple Y connector.

Grayscale
This describes the ability of a display to be in a state between full ON and full OFF. Each of these definable states is a gray level. The grayscale is composed of the number of gray levels. The more levels from OFF (black) to ON (white) you can distinguish on a display the better. For an example of a test pattern used to check grayscale see: Square Grayscale Snakes


HDCP (High-Bandwidth Digital Content Protection)
HDCP encryption is used with high-resolution signals over DVI and HDMI connections and on D-Theater D-VHS recordings to prevent unauthorized duplication of copyrighted material.

HD DVD Disc
HD DVD is a blue laser disc system developed by primarily Toshiba that can hold up to 15GB on a single-layer disc and 30GB on a dual-layer disc. For more information see: What is HD DVD? See also Blu-ray Disc for a competing technology.

HD Lite
To save bandwidth some of the HD providers are transmitting what is reduced resolution HD signals. Can be either 1440×1080i or 1280×1080i, but because it is not the full 1920×1080 pixels, the term HD Lite has been applied.

HDMI (High Definition MultiMedia Interface)
HDMI assures that the best video signal is always sent from source (e.g., HDTV signal) to the display (e.g., plasma television). It does this by allowing uncompressed video and multi-channel audio data to be input to the display device through one single cable. The need for multiple analog connections for high-resolution audio and video are eliminated. Without a HDMI connection one would need 3 video connections for high definition video and 6 audio connections for high-resolution audio. Simply stated the HDMI connection combines the DVI connection and the digital coax audio connection into a common connection. Most all of the hDMI connections will incorporate the HDCP copy protection.

HD-ready
Describes a television that is capable of displaying one or both of the prescribed high-definition television formats (720p, 1080i) but is not equipped with the requisite tuner/converter to receive digital signals. In order to be called a television it will need some type of tuner and HD Ready TVs are equipped with NTSC (analog) tuners. Today they are not sold anymore because the FCC has mandated TVs must have digital tuners. There are HD capable monitors that do not have any tuner at all still sold today however.

HDTV (High-Definition Television)
HDTV stands for High Definition Television. HDTV refers to the highest-resolution formats of the 18 total DTV formats. With twice the vertical and horizontal picture resolution, the picture of HDTV is approximately twice as sharp as that of NTSC. HDTV has widescreen aspect ratio of 16:9 and Dolby Digital sound system. Currently used HDTV broadcast formats - 1080i and 720p both offer reduced artifacts like ghosting and dot crawl, but will add other artifacts. See HDTV Artifacts for more information.

High Def
Is short for High Definition.

High Definition
Usually refers to a video format consisting of either 720 active lines of progressive video or 1080 active lines of either progressive or interlaced video. For more info see: HDTV Introduction.

HTPC
Home Theater Personal Computer.  A specialized PC that is intended for use in a home theater enviroment.  Not only do HTPCs require video cards that will interconnect with televisions, but generally a TV tuner card, DVD or HDM disc drive, multichannel audio (5.1 or 7.1) and large storage hard drive or drives are required for the PC to be considered a HTPC.


IEEE-1394 (also FireWire or i.LINK)
High-speed digital video and data interface technology adopted by the Institute of Electrical and Electronics Engineers; a nascent standard for connecting digital television and computers to various components and peripherals, such as Digital VHS, set-top HDTV tuner boxes and digital video camcorders.

Interactive Television
This is when TV programming features interactive content and enhancements, blending traditional TV viewing with the interactivity of a personal computer.

Interlaced Scanning
Interlaced scanning is a method based on the principle that the screen shows every odd line at one scan of the screen and then all the even lines in a second scan. This method of video transmission was adopted at the dime when the receiving device was a CRT. Due to bandwidth considerations the maximum resolution of an analog signal at that time was approximately 300 lines of video. That combined with the fact that CRTs needed to have their phosphors refreshed at at least 60 times per second (50 in Europe) to reduce flicker, the scheme of interlacing was employed. NTSC video employed the two passes to increase the perceived resolution on CRT to double the lines of video. Currently 480i video consists of two 240 line passes and 1080i video consists of two 540 line passes.


LCD (Liquid Crystal Display)
LCD stands for Liquid Crystal Displays. LCD technology is one of the methods used to create flat-panel TVs. The display consists of two polarizing transparent panels and a liquid crystal solution sandwiched in between. An electric current passed through the liquid causes the crystals to align so that light cannot pass through them. Each crystal acts like a shutter, either allowing light to pass through or blocking the light. The pattern of transparent and dark crystals forms the image. In addition to the flat panels, LCD panels are also used in projection type displays, both rear projection and front projection. See Also: LCD Response Time Explained

LCoS (liquid crystal on silicon)
A type of LCD and projection TV display technology (can be used in rear-projection and front-projection TVs), LCoS sandwiches liquid crystals between a plate of glass and a silicon microchip rather than between two layers of glass. Where the LCD has the light behind the panel, the LCoS panel reflects the light like the DLP chips. As such LCoS is used in projection systems.

Letterbox
Letterbox refers to the image of a wide-screen picture on a standard 4:3 aspect ratio television screen, typically with black bars above and below. It is used to maintain the original aspect ratio of the original source (usually a theatrical motion picture of 16:9 aspect ratio or wider).

Light output
Is the amount of light produced by a front projector. Expressed in “lumens” or “ANSI lumens,” with the higher number indicating greater light output.

Lumen
The unit of measure for light output of a projector or display.

Luminance
The brightness or black-and-white component of a color video signal. Determines the level of picture detail.


Multicasting
The option to multicast was made possible by digital technology to allow each digital broadcast station to split its bit stream into 2, 3, 4 or more individual subchannels of programming and/or data services. (For example, on channel 7, you could watch 7-1, 7-2, 7-3 or 7-4.) Currently there are stations that have divided their channel up into up to 5 SD subchannels allocating roughly 3.8 Mbits to each subchannel out of the 19.4 Mbits available. Since it is generally accepted 11 Mbits are required for a HD channel to maintain a minimum of macroblocking, stations will often limit the additional SD subchannels to 2.


Native Resolution
The highest resolution signal that a TV or monitor can accept. It is important to note that while a particular device (Digital-HDTV) is able to receive the resolution, it may not be capable of displaying it. An example would be the popular plasma displays that have a pixel resolution of 1024×768 or 1366×768. While these sets will receive a signal of 1920×1080 they are not capable of displaying the full resolution. The received images is scaled to the addressable resolution of the display.

In the case of plasma displays, the native resolution is the actual number of plasma cells that can be illuminated at once, and it’s the very first thing you should check when shopping for a plasma display. In order to enjoy high-definition programming, your TV must have a minimum native resolution of 720p. Common native resolutions of displays sold as HDTV are 1024×768, 1024×1024, 1280×768, 1280×720, and 1920×1080. The first two fall short of the ATSC resolution for HDTV, but the CEA considers a display HD as long as it has a minimum of 720 pixels high.

NTSC (National Television Systems Committee)
NTSC or National Television System Committee is the organization that develops technical standards for black-and-white television and color television. NTSC established the 525-line (480 visible) analog broadcast TV standard. The new DTV digital broadcast standard will replace NTSC for OTA broadcasting in February 2009. At that time people with NTSC only TV sets will need an external digital tuner.


OTA or Over-The-Air Broadcast
Over-the-air Broadcast is also called Terrestrial Broadcast. It is standard over-the-air broadcast to an antenna, as opposed to satellite or cable transmission. Currently it can be either NTSC (analog) or ATSC (digital) but will got to all digital in February 2009. For more information see: OTA Antennas

Overscan
Overscan is basically when the picture displayed on the screen will be only a portion of what is transmitted. Effectively the actual edges of the picture is pushed behind the bezel. All TV displays will overscan and digital based TVs will use the internal scaler to enlarge the picture, usually about 5% to 10%. For more information on this see: Hooking Up A PC to A HDTV


Picture-in-picture (PIP)
Picture-in-picture is a television feature in which you can see one program inside a small window on the screen, while watching another program on the large background screen. You can choose whatever you wish you can watch two TV programs simultaneously or you can watch TV and video or DVD at the same time. See A Discussion on PIP

Pillarboxing
See Barn Doors.

Pixel
Short for “picture element.” The smallest bit of data in a video image. The smaller the size of the pixels in an image, the greater the resolution. HDTV broadcasts are either 1280 pixels wide by 720 pixels high OR 1920 pixels wide by 1080 pixels high.

Plasma Displays (PDP)
Plasma display is created by thousands of tiny tubes filled by ionized gas in a plasma state. Plasmas are available in resolutions of 852×480, 1024×768, 1024×1024, 1366×768, and 1920×1080.

Progressive Scanning
Progressive scanning offers rather smooth picture as the horizontal lines are scanned progressively or in succession in a vertical frame that is repeated 60 times a second. Some displays, for example LCD, DLP and plasma use progressive scanning method, while CRTs may use progressive (e.g. in computer monitors) or interlaced scanning method.



Rear Projection
Rear projection is a TV system where the picture is projected against a mirror inside the cabinet and you can watch it as you would an average television. Until recently, the rear projection TVs comprised three CRTs but the new types of rear projection TVs include LCD and DLP. The image is reflected onto the rear of a Fresnel lenticular screen which requires a seating position on front of the screen for best viewing.

Refresh Rate
The refresh rate for a monitor is measured in hertz (Hz) and is also called the vertical frequency, vertical scan rate, frame rate or vertical refresh rate. The old standard for monitor refresh rates was 60Hz, but a new standard developed by VESA sets the refresh rate at 75Hz for monitors displaying resolutions of 640×480 or greater. This means that the monitor redraws the display 75 times per second. The faster the refresh rate, the less a CRT monitor will flicker.

Resolution
Resolution reflects the density of lines, and dots per line which make up a visual image. It is measured by the number of pixels displayed. The level of resolution directly affects picture quality. Usually the higher number of lines and dots means also sharper and more detailed picture. Analog TV has a little over 200,000 color pixels while HDTV, with 1080 vertical pixels and 1920 horizontal ones, has more than 2 million pixels creating the image. The resolution of ATSC HDTV broadcasts is either 1280×720 or 1920×1080 pixels.


Sampling
This is the digital process by which analog information is measured, often millions of times per second, in order to convert analog to digital.

SED
Surface-conduction Electron-emitter Display. Basically a flat panel display with three guns per pixel. See: The SEDs are Comming!

SDTV (Standard-Definition Television)
SDTV stands for Standard Definition Television. The SDTV picture, having either in 4:3 or 16:9 aspect ratios, is better and of higher quality than the one of NTSC, however, it does not reach the quality and resolution of HDTV. SDTV is based on 480 lines of vertical resolution and in both interlaced and progressively scanned formats. Often the current analog NTSC video is referred to as SDTV because the resolutions are nearly the same.

STB or Set-top Box
Also called converter boxes, these receivers convert broadcasts (either analog cable, digital cable, or HDTV) for display on a television. HDTV-ready TVs (those without a built-in HDTV tuner) must be connected to a compatible HDTV tuner set-top box in order to receive digital television programs.

SVGA
This acronym is short for the “Super Video Graphics Array” display mode. SVGA resolution is 800 x 600 pixels.

S-Video
Separated video. An encoded video signal which separates the brightness from color data. S-video can greatly improve the picture when connecting TVs to any high quality video source such as digital broadcast satellite (DBS) and DVDs. S-Video connections will carry 480i SD signals.


TV or Television
What we are talking about!


UHF
Ultra high frequency, the range used by OTA TV channels 14 through 69.

Ultra High Definition
Any format that exceeds HDTV like 2500×2000 and 4000×2000 - the format of choice for the new Digital Cinema. The formats shown are also referred to as 2K video. There is also 4K video.

Upconverting
Process by which a standard definition picture is changed to a simulated high-definition picture. It also could be construed to be the conversion from 720p to 1080i or 1080p as well. Basically anytime the resolution of pixels are increased, it is upconverting.


VGA
This acronym is short for the “Video Graphics Array” display mode. VGA resolution is 640 x 480 pixels.

VHF
Very high frequency, the range used by OTA TV channels 2 through 13.


Widescreen
Widescreen TV is the television with 16:9 aspect ratio. 16:9 is the aspect ratio of DTV formats used in all HDTV (High Definition TV) and some SDTV (Standard Definition TV); it stands for 16 units of width for every 9 units of height.

Comments…



REV. 1

Blog Of Hawaii

page template

High Definition Blog is proudly powered by WordPress
Entries (RSS) and Comments (RSS).

-->