ATSC Standards document a digital television format that will have replaced the analog NTSC television system by February 17, 2009 in the United States, and August 31, 2011 in Canada. It was developed by the Advanced Television Systems Committee.

The high definition television standards defined by the ATSC produce wide screen 16:9 images up to 1920×1080 pixels in size — more than six times the display resolution of the earlier standard. However, many different image sizes are also supported, so that up to six standard-definition "virtual channels" can be broadcast on a single 6 MHz TV channel.

ATSC also boasts "theater quality" audio because it uses the Dolby Digital AC-3 format to provide 5.1-channel surround sound. Numerous auxiliary datacasting services can also be provided.

Broadcasters who use ATSC and want to retain an analog signal must broadcast on two separate channels, as the ATSC system requires the use of an entire channel. Virtual channels allow channel numbers to be remapped from their physical RF channel to any other number 1 to 99, so that ATSC stations can either be associated with the related NTSC channel numbers, or all stations on a network can use the same number. There is also a standard for distributed transmission (DTx) which allows for booster stations.

ATSC standards are marked A/x (x is the standard number) and can be downloaded freely from ATSC website (see external links]] below).

Many aspects of ATSC are patented, including elements of the MPEG video coding, the AC-3 audio coding, and the 8VSB modulation. As with other systems, ATSC depends on numerous interwoven standards, e.g. the EIA-708 standard for digital closed captioning, leading to variations in implementation.

Resolution

The ATSC system supports a number of different display resolutions, aspect ratios, and [[frame rates. The formats are listed here by resolution, form of scanning (progressive or interlaced), and number of frames (or fields) per second (see also the TV resolution overview at the end of this article). The table includes formats from both A/53 Part 4 (MPEG-2 Video System Characteristics) and A/63 (Standard for Coding 25/50 Hz Video).

The different resolutions can operate in progressive scan or interlaced mode, although the highest 1080-line system cannot display progressive images at the rate of 59.94 or 60 frames per second. (Such technology was seen as too advanced at the time, plus the image quality was deemed to be too poor considering the amount of data that can be transmitted.) A terrestrial (over-the-air) transmission carries 19.39 megabits of data per second, compared to a maximum possible bitrate of 10.08 Mbit/s allowed in the DVD standard.

"EDTV" displays can reproduce progressive scan content and frequently have a 16:9 wide screen format. Such resolutions are 720×480 in NTSC or 720×576 in PAL, allowing 60 progressive frames per second in NTSC or 50 in PAL.