Difference Between Digital And High-Definition Television
Digital television (DTV) enables broadcasters to offer movie-quality picture and sound. DTV is generally more lithe and well-organized than the standard “analog” system. The number of programs a station can send on one digital channel depends on the level of resolution.
HDTV provides high-resolution programming, thanks to an increased number of horizontal scan lines on the screen. HDTV cameras and receivers combine to boost the amount of video information, resulting in a sharp digital image that matches the clarity and resolution of 35-millimeter film. The format also imitates the wide-screen dimensions of a theatrical movie, with an aspect ratio (units of width to units of height) of 16 by 9 (usually expressed as “16:9”). HDTV-compatible sets have the capacity to produce high-quality digital stereo sound or, when coupled with a home-theater system, surround sound.
Fully integrated HDTV sets are available, but some customers have opted to purchase an HD monitor with a separate receiver box, which also serves as a digital-to-analog converter that can be connected to a standard TV (but will not provide HDTV picture and sound).
In recent years, there has been a steady rise in the amount of HD programming available to viewers. The major networks—ABC, CBS, Fox, NBC, and PBS—now broadcast in HD as do the premium channels, including HBO HD, Showtime HD, and Cinemax HD. Numerous movies are available in HD on ON DEMAND. ESPN HD, a high-definition simulcast service of ESPN, was launched in March 2003, and ESPN2 HD, a simulcast of ESPN2, was launched in January 2005 to expand HDTV coverage of the excitement of professional sporting events. There are also such popular cable channels as Discovery HD and TNT HD, as well as local news and sports in HD.