A digital TV antenna is a television antenna that allows you to receive digital signals over the air. It is similar to an analog antenna because it interprets signals it receives in order to provide you with television entertainment and media. However, digital signals generally provide a clearer picture, and television is no longer sent over analog signals.
A traditional analog antenna, or "rabbit ears" as they were sometimes called, used to pick up analog RF signals in the air. The antenna could receive the information and display television programming. Digital antennas serve essentially the same function, but the information they are receiving is transmitted digitally, and not with analog RF signals.
A digital TV antenna can be attached directly to your TV. It has to be able to pick up a digital signal, however, so a signal has to be available from a satellite or from another source of digital programming such as a local broadcast station. It can also be attached to the roof of a home where it has access to a digital signal.
In order to transmit the television programming to a TV, the TV must be able to decode the digital signals it receives from the digital TV antenna. All televisions produced and sold after February of 2009 have the ability to decode digital signals built in. Televisions produced prior to 2009 may or may not be able to receive signals from a digital tv antenna, depending on whether the television has a digital converter or not.
In order to ensure that everyone has access to digital television, converter boxes are available. These converter boxes allow people with old analog televisions to still receive programming through an antenna, even though all the programming is not distributed in digital format. The boxes convert the digital signals to analog signals that your old TV can understand.
The change to digital television broadcasting as opposed to traditional analog broadcasting went into effect in February of 2009. The government wanted the change from digital to analog TV in order to free up radio frequencies for other military and other uses, since only a limited amount of data can travel along analog signals. Consumers were in favor of the switch to digital TV because digital TV provides a clearer picture and more features.
Digital TV should not be confused with high definition TV. While most digital signals are broadcast in high definition, having a digital TV antenna alone is not sufficient to ensure having access to high definition TV. The TV must also be able to display in high definition and to decode the high definition digital signals in order for a digital TV antenna to provide you with high definition TV.