Glossary of HDTV Terms
720p: An image of 720 lines with an associated 1280 pixels, the minimum for HD programming. The “p” stands for “progressive,” which refers to how the pixel rows appear: progressively vs. interlaced.
1080i: An image of 1080 lines with an associated 1920 pixels. The “i” stands for “interlaced,” which refers to the broadcast process by which the image appears. Lines are displayed in two different sets vs. the progressive one.
1080p: The new way to display a high-definition image, combining the smoother broadcast of the progressive 720p with the high frame rate of the 1080i.
A/D Conversion: When a signal is converted from an analog format to a digital one.
Aspect Ratio: Describes the relationship between an image’s width and height. HDTV’s standard ratio is 16:9 or widescreen, which is similar to a film’s original size and look.
ATSC (Advanced Television Systems Committee): The standards established by the Advanced Television Standards Committee (ATSC) for digital television standards in the United States. Traditional television is NTSC.
Component Video: Component video separates video signals into three streams (of blue, red, and green), which are then carried by three individual cables.
Compositive Video: What a picture signal is called before combining with a sound signal and being modulated onto an RF carrier. In a composite video signal, there are three sources: Y, U, and V or simply YUV.
Contrast Ratio: The ratio of a picture signal’s white and black components.
Digital Cable Ready (DCR): Refers to a television being capable of accepting one-way HD cable signals without the need of an external box. The installation of a special cable card (CableCard, available from local cable provider) is all that’s needed.
Digital Television (DTV): The digital broadcast formats that form the new ATSC, assigned to replace the traditional television system (NTSC). There are 18 formats in all, each defined by its own standards for resolution, aspect ratio, etc.
Enhanced Definition Television (EDTV): Refers to some digitial formats that are of higher resolution than standard NTSC, but not to the level of HD.
HD-ready: A television that is capable of HD display but without the necessary digital tuner/converster to receive digital signals.
HDTV: Refers to digital formats that meet the minimum standards to be considered high-definition, including a scanning format of 720p, 1080i, or 1080p.
High Definition Monitor: A television that can receive and show HDTV, but not at the quality of true HDTV.
Interactive Digital Cable Ready (iDCR): Like Digital Cable Ready units, iDCR can receive HD and non-HD signals without an external box. All that is needed is a CableCard. But unlike non-interactive Digital Cable Ready, iDCR can purchase Pay Per View content with a remote control. DCR units need to contact the provider via phone.
Interlaced Scanning: Broadcast process in which odd- and even-numbered lines of an image/picture are scanned and then displayed consecutively as two separate fields but superimposed together to create one image on the screen.
NTSC (National Television Standards Committee): The current set of standards for analog television.
Native Resolution: The number of plasma cells that can be illuminated at once. HD programming requires a minimum native resolution of 720p.
Progressive Scanning: Broadcast process in which the lines of an image/picture are scanned consecutively, without interruption (as is the case with an “interlaced scan.”) This process creates a smoother delivery of the image.
Refresh Rate: Refers to the vertical frequency (or frame rate) of a monitor. The new standard sets the refresher rate at 75Hz (hertz) for monitors with resolutions of 640×480 or greater. It means that the display is redrawn or refreshed 75 times per second and the faster the rate, the less the flicker.
SDTV (Standard Definition Television): The standards established for televisions since the 1940s.
Viewing Angle: The area from which an image can be clearly seen on a display. The largest is the superwide 178-degree viewing angle.