Analog television

The prevailing technology in use for more than 50 years to transmit conventional television signals. By comparison, LPs are an example of analog recording technology that have been superseded by digital media such as compact discs and MP3 files.

Bandwidth

The amount of spectrum used for a broadcast application. For Digital TV, the FCC-approved plan assigns 6 MHz (megahertz) of the broadcast spectrum for each television broadcaster. This bandwidth can be allocated in different ways: one SDTV (standard definition) signal, one HDTV (high definition) signal, or a combination of the two (multicasting) — plus datacasting.

Broadcasting

Transmission of a television signal over the air for receipt by an antenna.

Datacasting

Transmission of data along with video signals that can be stored for later retrieval. This can include video, audio, graphics and text, especially for educational programming.

Digital TV (DTV)

A broadcast signal that is encoded as a series of zeroes and ones - the digital code used in computers, calculators, compact discs and on the Internet.

High definition television (HDTV)

High definition television. This is the digital format that provides crystal-clear quality, wide-screen pictures with surround sound comparable to a CD. The aspect ratio of HDTV is 16:9 as compared to the traditional 4:3 format.

Multicasting

Simultaneous transmission of several programs within a single Digtial TV channel. See also "Bandwidth" above.

Public service broadcasting

Educational and informational broadcasting services that respond to the needs of a wide range of audiences, many of them under-served by other media.

SDTV (standard definition television)

This digital format is comparable to CD-quality video Digital TV delivers picture and sound without noise, ghosts and interference and could include a wide range of data services.