Preceding digital television (DTV), all televisions encoded pictures as an analog signal by varying signal voltage and radio frequencies. DTV is fast replacing analog TVs as digital broadcasting enables broadcasters to offer television with movie-quality picture and sound. Analog systems are more commonly known as NTSC systems.
A U.S. Senate panel has set an April 7, 2009, as the deadline for television stations to switch entirely from analog to digital broadcasts. Analog televisions will work until all analog broadcasting ceases. Once the transition to complete DTV has taken place, a converter will be required to receive DTV signals and change them to the analog format of these older types of televisions. However, these DTV-to-analog converters will not produce true DTV quality.
Analog televisions are now commonly referred to conventional televisions.
See also DTV.