Comb filter - A circuit in NTSC sets that separates the color information from the brightness information.
CRTC - Canadian Radio-television and Telecommunications Commission, the federal regulatory body for television programming and broadcasting in Canada.
Down Converting - Process by which a high-definition signal is converted to a standard definition picture.
Aspect Ratio - the ratio of image width to image height. The term may apply to the display device configuration, or the shape of the content being displayed. (See Letterboxing) HDTV uses an aspect ratio of 16 units wide by 9 units high. Conventional television programming and displays are at an aspect ratio of 4 - 3. Digital SDTV programs may aspect ratios from 4 - 3 to 16 - 9, dependant on content and its source (e.g. upconverted NTSC is likely to be 4 - 3).
Letterbox - The full display of a wide aspect ratio 16 - 9 picture on a display of aspect ratio 4 - 3 will result in black bars above and below the picture. This arrangement is referred to as "Letterbox" and is often seen during movies shown on television.
HDTV - (High Definition TV) - A TV that displays 1280x720 pixels or better.
Pan-and-scan - A method of broadcasting a wide screen film on a 4:3 channel. Most of the time just the center of the image is shown. (The right and left edges are clipped off.)
Interlaced Scanning - Some HD televisions and most conventional televisions use the "interlace" method of scanning, in which the picture is transmitted and painted on the screen in two passes. In the first pass, every other line is painted and in the second, the lines in between. Some display types, such as LCD, plasma and DLP cannot display directly images transmitted as interlaced signals and must convert them to a progressive format prior to their display.
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.
MTS - (Multi-channel Television Sound) - This refers to an analog NTSC TV equipped with stereo and SAP (separate audio program) features.
YPrPb - Color representation requires three independent variables. CRTs - prefer red, green, and blue. Ink jet printers prefer yellow, magenta, and cyan. NTSC encodes color as luminance (brightness), hue (color), and saturation (absence of white in colors). Storage media such as DVDs prefer Y, Pr, and Pb, where Y is luminance, Pr is Y-red, and Pb is Y-blue. This is because Pr and Pb can be at lower resolution and not degrade the image noticeably, thus saving storage space.
Pixel - A picture element; a single displayable video dot. HDTV requires from 1 to 2 million pixels in the display for full resolution images to be shown.
Composite Video - An analog video signal (NTSC, PAL or SECAM) that includes both luminance (brightness) and chrominance (color) signals encoded together to form a single signal.
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 _ High-definition TV (HDTV).
A/D - Electronic device that connects an analog television signal to a digital system.
HDTV - High Definition Television - HDTV is a TV system having approximately twice the vertical and horizontal picture resolution of today's NTSC TV and having a wide aspect ratio of 16 - 9. Two HDTV formats are currently in use; (a) 1920 pixels per line and 1080i lines per frame and (b) 1280 pixels per line and 720p lines per frame. HDTV can be recognised by its spectacular picture resolution, freedom from annoying artefacts and impressive 5.1 channel surround sound.
MPEG-2 - (Motion Picture Experts Group technical standard 2) - This is a widely used standard for digital encoding of motion pictures. It typically achieves a 50 to 1 compression of data. It achieves this mainly by not retransmitting areas of the screen that have not changed since the previous frame.
Dolby Digital 2.0 - This is a two channel (stereo or Pro Logic) version of Dolby Digital. It is often used by DBS systems.
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 channels of programming and/or data services. (For example, on channel 7, you could watch 7-1, 7-2, 7-3 or 7-4.)
