Digital Visual Interface connections allow users to create a digital-to-digital connection between their display and source. We most commonly see the digital-to-digital connection between flat screen monitors and computers. However, new HDTV set top boxes can be found which offer DVI output.
The signal your television receives with an antenna is analog. Sometimes the picture is fuzzy, sometimes it comes in perfectly clear, and sometimes it fades in and out. With a digital signal, the signal is either on or off, so "fuzziness" is not possible. That is not to say that an analog signal always looks fuzzy. A high quality analog signal also produces beautiful, clear images. The signals are just not quite as consistent as digital.