What is DTV Transition?
The switch from analog to digital broadcast television is referred to as the digital TV (DTV) transition. In 1996, the U.S.Congress authorized the distribution of an additional broadcast channel to each broadcast TV station so that they could start a digital broadcast channel while simultaneously continuing their analog broadcast channel.
Later, Congress mandated that February 17, 2009 would be the last day for full-power television stations to broadcast in analog. Broadcast stations in all U.S. markets are currently broadcasting in both analog and digital. After February 17, 2009, full-power television stations will broadcast in digital only.