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television (hardware) terms


video connection types:
"Component Video" -- uses three separate signal wires to convey the picture and is the best format.
"Super Video" or "S-Video" -- uses two signal wires and is next best format.
"Composite" -- uses a single signal wire and is least best.

Component Video connections - usually found only on certain DVD players, digital satellite systems, and HDTV receivers - use three RCA-ended video interconnects, often color-coded as red, green, and blue (even though they are not compatible with computer-display RGB inputs).

Composite connections are the most common type, and are your only option with standard VCRs. They are connected with a single interconnect with RCA ends, color-coded yellow. Use video, not audio cable for a video connection; audio cables do not have the smooth performance in the high frequencies needed for video signals (which are at least a hundred times higher than audio signals).

S-Video connectors - found on almost everything except standard VCRs - are about the size of an RCA connector, but the shell has two kinks in it (for proper orientation) and inside are four thin pins.

resolution - Vertical resolution for our 60-year-old NTSC television system is fixed at 240 lines. In television, the picture is systematically painted one picture element ("pixel') at a time. The scan goes from left to right horizontally, then skips back to the left side of the screen one line down.

Horizontal Resolution: specs for typical sources:

source h lines
analog TV broadcasts 330
VHS VCRs 240
DVD 480*
HDTV (high definition TV)   up to 540**
laserdisk 420
digital TV (DTV) 480

*up to 500 lines
** 540 horizontal lines = 1,080 lines of resolution

(S)VGA - sVGA inputs allow a television to serve as a computer monitor
2 15-pin D-sub (S)VGA inputs (one supports PC connection with a mini-plug audio jack for PC applications, the other provides connection for an HDTV converter or other high-resolution source component with RCA-type audio jacks).
"VGA monitor "plug-and-play" convenience is supported via EDID data reporting through DDC2B protocol."

NTSC -- 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.

Analog TV
Today's "standard" television broadcasts in analog TV, which receives broadcast signals in the NTSC format. Analog technology has been in use for the past 50 years to transmit conventional TV signals to consumers. Analog signals vary continuously, creating fluctuations in color and brightness.
Aspect Ratio
The width to height proportion of a TV screen. Current analog TV's have a 4:3, or (16:12) ratio. The HDTV ratio is 16:9, which is close to movie and theatre screen ratios.
An acronym for "Advanced Television Systems Committee", and the name of the DTV system used by broadcasters in the U.S.
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 term is short for "Coder-decoder." A codec is a device that converts analog video and audio signals into a digital format for transmission. It also converts received digital signals back into an analog format.
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.
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.
See "codec." A device or program that translates encoded data into its original format (i.e., it decodes the data.)
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 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 Television (DTV)
Digital TV is the umbrella term encompassing High-definition Television and several other applications, including Standard Definition Television, datacasting, multicasting and interactivity.
Digital Tuner
A digital tuner serves as the decoder required to receive and display digital broadcasts. It can be included inside TV sets or via a set-top box.
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.
Down Converting
Process by which a high-definition signal is converted to a standard definition picture.
Enhanced TV
Also known as "datacasting." This term is used for certain digital on-air programming that includes additional resources downloaded to viewers. Some forms of enhanced TV allow live interaction; other forms are not visible on-screen until later recalled by viewers. Producers add these options to some digital programming to enhance program material -- allowing viewers the ability to download related program resources to specially equipped computers, cache boxes, set-top boxes, or DTV receivers.
This acronym stands for "Enhanced Definition Television." It refers to a complete products/system with at least a digital receiver display scanning format, and Dolby Surround Sound audio output capabilities.
Federal Communications Commission
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.
"High-definition Television." This is the most superior video picture available in Digital TV. In the U.S., the 1080i and 720p formats in a 16:9 aspect ratio are the two acceptable HDTV formats. HDTV is a component of DTV.
Interlaced Scanning
This process divides and presents each video frame as two fields. Imagine a video frame being divided by the odd and even horizontal lines that make up the picture. The first field presents the odd lines; the second field represents the even lines. The fields are aligned and timed so that, with a still image, the human eye blends the two fields together and sees them as one. Motion in the image makes the fields noticeable. Interlace scanning allows only half the lines to be transmitted and presented at any given moment.
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).
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 channels of programming and/or data services. (For example, on channel 7, you could watch 7-1, 7-2, 7-3 or 7-4.)
This refers to the legal obligation of cable companies to carry analog or digital signals of over-the-air local broadcasters.
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.
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.
Pixels Per Inch
A pixel per inch (PPI) is a measure of the sharpness (that is, the density of illuminated points) on a television display screen.
Progressive Scanning
A system of video scanning where lines of a picture are displayed consecutively (unlike interlaced).
Refers to the quality, sharpness, and clarity of an image. The higher the resolution, the more picture detail there is. Many things affect picture quality, including number of bits, pixel count, format, receiver quality, cameras, lenses and lighting used for live or taped programming. The number of pixels displayed measures resolution. One of the high-definition picture formats is composed of 1080 active lines, and each line is composed of 1920 active pixels. Therefore, each frame has over 2 million (1080x1920=2,073,600) color pixels creating the image. By way of contrast, today's typical analog television is roughly equivalent to 480 active lines, with each line holding about 440 pixels. So, each frame has a little over 200,000-color pixels in use creating the image.
This is the digital process by which analog information is measured, often millions of times per second, in order to convert analog to digital.
Set-top Converter Box
This unit sits on top of the viewer's analog TV, receives the Digital TV signal, converts it to an analog signal, and then sends that signal on to the analog TV.
Standard Definition TV Format (SDTV)
There are two main digital formats - HDTV and SDTV. SDTV typically does produce better quality images than that of traditional analog TV and pictures somewhat akin to digital cable. However, its images are not nearly as sharp as the images from the ultimate form of digital television ¾ High-definition TV (HDTV).
This acronym is short for the "Super Video Graphics Array" display mode. SVGA resolution is 800 x 600 pixels.
Terrestrial Broadcasting
This is a broadcast signal transmitted "over-the-air" to an antenna.
Process by which a standard definition picture is changed to a simulated high-definition picture.
This acronym is short for the "Video Graphics Array" display mode. VGA resolution is 640 x 480 pixels.
Wide Screen
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.
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If my TV set has 800 lines of resolution, can it display a 720 line HDTV signal?