A digital TV station is a physical or virtual point of origin, or broadcaster, of digital television programming. Typically, a digital TV receiver of some kind is required to view these transmissions on a television. The programs broadcast by a digital TV station may be entirely digital in nature or produced using traditional equipment and then converted to a digital format.
For most of television's lifespan, stations have used analog television signals to transmit images and sound. Traditional analog broadcasts use radio signals, sent through the air, to supply communities with television programming. These radio waves are received by antennas, which carry the signal to a television for viewing.
While a digital TV station may send its signal using radio waves, many stations transmit signals that require digital TV receivers, also called digital TV boxes, to receive the signal and convert it into picture and sound. A cable TV or satellite TV provider will typically supply such a receiver to its subscribers. Some televisions contain a digital tuner, which helps process a digital signal, but in most cases a receiver is also needed for full signal reception.
Digital TV is generally preferred by broadcasters and viewers because it offers picture and sound quality that is typically superior than that of analog television. Digital TV reception is also more popular with viewers because its direct signal connection, through the receiver box, is more reliable than a signal sent over the air. This technology also allows digital TV stations to offer multiple channels of programming through one signal, using digital compression, which increases program choices for viewers.
A digital TV station broadcasts programming using a digital signal, but it does not necessarily produce all of the transmitted material itself. Typically, stations obtain programs made outside the station and broadcast them to viewers. Some of this programming is made using traditional equipment and methods, which is then translated to a digital format for broadcast. True digital TV is achieved when the programming is created using digital cameras, the signal is sent digitally, and the programming is received on a digital TV.
The number of digital TV stations around the world has grown substantially since the 1990s. Although stations in Japan, the U.S. and Europe were among the first to offer digital programming, digital TV is now available on every continent. On June 12, 2009, U.S. television stations began broadcasting only digital signals. This was mandated by the U.S. government to allow more room on analog airwaves for public safety communication, such as police and fire radios, and to offer consumers more channels and interactive video services.