- Digital TV is simply the process of transmitting television signals by digital means, either over the air, through a system of cables or via satellite. It provides an upgrade over the older analog broadcasting in terms of picture and sound quality (including HD video), the ability to transmit a greater amount of data and to even broadcast separate sub-channels simultaneously with the main channel.
- High definition is the term for the higher-resolution video shot by HD cameras, broadcast by the various networks, and received by TVs capable of displaying the technology. It involves a greatly increased number of lines of resolution (1920x1080), a higher frames-per-second ratio and an aspect ratio of 16:9, as opposed to the 4:3 used by older analog TVs. It also can feature Dolby Digital surround-sound audio with certain programs and channels.
- To process digital TV signals, a TV needs a digital (ATSC) tuner, mandatory in every TV produced since 2007 in anticipation of the digital transition. For older TVs with analog (NTSC) tuners, digital TV can still be viewed by connecting to a cable or satellite receiver box or a digital-to-analog converter box, available in stores that sell TVs and for which the government had a coupon voucher program to help defray the costs, though that has now ended.
- For cable and satellite customers, the transition had no real effect, though digital cable subscribers can also enjoy pay-per-view and on-demand programming as well as onscreen menus and other interactive features unavailable with standard cable. To view over-the-air programming, a standard antenna will work when connected to a TV with a digital tuner or to the converter box, which acts as a liaison between the antenna and the analog TV. The converter box scans and tunes the available channels; adjusting the antenna may help improve reception, just like with older TVs.
