What is the Difference in ATSC SDTV and LCD HDTV?

ATSC

The Advanced Television Standards Committee is a non-profit organization that sets voluntary worldwide standards for digital television, so everyone will be talking about the same thing when they use certain terminology. The ATSC's aim is to establish what constitutes standard-definition TV and what constitutes high-definition TV, among other standards. The standards suggested by the ATSC provide consumers with a clearer understanding of what they can expect from a television. Technically speaking, both SDTV and HDTV can be prefixed by the word "ATSC," because it refers to the ATSC standard resolution of each medium.

A liquid crystal display television screen or computer monitor uses liquid crystal technology to form images. LCD television screens have five layers: a white backlight; a polarizing filter; a pattern of red, green, and blue colors; liquid crystal cells; and another polarizing filter. The polarizing filters are used to align the light produced by the white back light in a specific direction. The light is sent from the backlight through the polarizing filter, and then sent through the red, green, or blue color filter. The picture is then plotted onto the liquid crystal cells before being aligned again by the second polarizing filter. LCD television screens are more energy-efficient than ordinary television screens and have virtually no visible flicker. An LCD television with the capability to support HDTV also can display SDTV images.

ATSC standards say SDTV must have a resolution of at least 640 x 480. Resolution refers to the number of pixels that make up a line of the image displayed on the screen. A pixel is a tiny square of color, and pixels are used to build the image being displayed. Very poor-quality recordings may have visible pixelation on screen, meaning you can see the squares that make up the image.

HDTV can be simply thought of as a television image made up of more pixels, which means it displays a sharper, more defined image. Two different standards have been established for HDTV. The first is 1280 x 720 pixels, which almost doubles the pixels that make up an SDTV image. The second standard is 1920 x 1080, which increases the resolution over SDTV by more than double. Both SDTV and HDTV can be defined by ATSC standards and both can be displayed on an LCD screen. The main difference between the two is the resolution.