The Difference Between NTSC Tuners & ATSC Tuners

By Matt Bennett

A tuner converts over-the-air (OTA) television transmissions into audio and video signals used by receiving devices to create pictures and sound. National Television System Committee and Advanced Television Systems Committee are two standards for television transmission that require separate tuners. NTSC is an analog standard that has been in place since 1941 and ATSC is the digital standard adopted in 1995.

Standards History

NTSC was developed for use with black-and-white television in 1941 and then modified in 1953 to allow for color broadcasts. This color standard for color televisions was designed to be backward compatible with the black-and-white broadcasts for which the standard was originally created. ATSC was developed by the Grand Alliance, a consortium designed to develop high-definition television (HDTV) standards in the early 1990s to support digital broadcasts of much higher picture quality and sound than the NTSC standard.

Tuner Function

Tuners convert over-the-air television transmission signals into audio and video signals for use with a display device, usually a TV set or digital video recorder. The tuner's specific tasks include demodulation to extract the specific signal, error correction, extracting specific channels, decompressing the signal, synchronizing the audio and video signals and formatting the signal to the optimal input for a display device. While these two types of tuners perform the same functions, NTSC tuners were designed to work with analog signals and ATSC tuners work with the much larger digital signals.

System Differences

NTSC tuners supported analog signals and used a standard frame refresh rate of slightly under 30 frames per second, 525 scan lines, an aspect ratio of 4:3 and a frequency modulation (FM) sound signal. ATSC tuners support digitial and HDTV signals with a wide-screen aspect ratio of 16:9, resolutions ranging from 352 x 288 pixels to 1920 x 1080 pixels, refresh rates ranging from 24 to 60 frames per second and Dolby Digital 5.1 surround sound.

Analog to Digital TV

ATSC broadcasts replaced NTSC broadcasts in the United States by June 12, 2009. Similarly, Canada converted by August 31, 2011, and Mexico will switch on December 31, 2021. The switch required consumers to buy digital-to-analog converter boxes to receive ATSC broadcasts on their old analog TVs. TVs sold in the U.S. since May 2007 are required by the Federal Communications Commission (FCC) to have built-in digital tuners. ATSC has been widely adopted by the U.S., with other countries such as Canada and South Korea completing transitions by 2012.

Geographic Restrictions

NTSC-M was the analog color television standard adopted by the U.S., Canada, Mexico and several Caribbean, Central American, South American and Asian countries. Japan adopted a variant of NTSC-M, called NTSC-J, which used minor differentiations in color voltage levels. Most European countries used the PAL-M standard, which uses different color encoding with the same bandwidth levels and frame rate. As a result, NTSC tuners displayed PAL broadcasts in black and white because it cannot decode the color information.