Definition: ATSC stands for Advanced Television Systems Committee. They are an international organization setting the standards for digital television. In time, they will replace the NTSC, which is an American organization overseeing analog TV transmissions.
When purchasing a digital television, ATSC is a term that will be listed on the specifications showing that the television has a built-in digital tuner. There are 18 frequencies in the digital spectrum, which includes high definition.
Examples:
32" HDTV with a bult-in ATSC digital tuner.