SDTV - "Standard Definition Television." SDTV are based on 480 lines of vertical resolution and may have either 4 - 3 or 16 - 9 aspect ratios, and surround sound. Several SDTV programs are sent together to form the simulcast bundle. While SDTV pictures are of significantly better quality than NTSC, they are not up to the standard of HDTV.
OTA - (over the air) - There are about 1500 OTA (terrestrial) TV stations in the U.S.
PCM - (Pulse Code Modulation) - This 2-channel digital audio standard is simpler than Dolby Digital.
CRTC - Canadian Radio-television and Telecommunications Commission, the federal regulatory body for television programming and broadcasting in Canada.
Multicasting - Term given to the sharing of the digital television channel among 2, 3, 4 or more individual programs and/or data services
Decoder - See "codec." A device or program that translates encoded data into its original format (i.e., it decodes the data.)
DTCP - (Digital Transmission Content Protection) - This is an encryption standard for IEEE 1394 that prevents the copying of first-run movies and pay-per-view events. DTCP is also called 5C Copy protection (in reference to the `five companies' that license it).
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.)
