Digital television pedia

) is a telecommunication system for broadcasting and receiving moving pictures and sound by means of digital signals, in contrast to analog signals used by analog (traditional) TV. DTV uses digital modulation data, which is digitally compressed and requires decoding by a specially designed television set, or a standard receiver with a set-top box, or a PC fitted with a television card. Introduced in the late 1990s, this technology appealed to the television broadcasting business and consumer electronics industries as offering new financial opportunities.

Digital television has several advantages over traditional analog TV, the most significant being that digital channels take up less bandwidth space. This means that digital broadcasters can provide more digital channels in the same space, provide High-Definition digital service, or provide other non-television services such as pay-multimedia services or interactive services. Digital television also permits special services such as multicasting (more than one program on the same channel) and electronic program guides. The sale of non-television services may provide an additional revenue source. As well, digital television often has a superior image, improved audio quality, and better reception than analog.

However, digital television picture technology is still in its early stages. Digital television images have some picture defects that are not present on analog television or motion picture cinema, due to present-day limitations of bandwidth and the compression algorithms such as MPEG-2. When a compressed digital image is compared with the original program source, such as a 35mm motion-picture film print, some digital image sequences may have distortion or degradation such as quantization noise, incorrect color, blockiness when high-speed motion is depicted, or a blurred, shimmering haze.