Digital Terrestrial Television (DTTV or DTT) is an implementation of Digital Video Broadcasting (DVB) technology to provide a greater number of channels, and digital quality of sound and picture, through a conventional aerial instead of a satellite dish or cable connection. Digital terrestrial television is also known as DVB-T.

Transmission

DTTV is transmitted on Radio frequencies that are similar to standard Analogue television, with the primary difference being the use of multiplex transmitters to allow reception of multiple channels on a single frequency range (such as a UHF or VHF channel).

The amount of data that can be transmitted (and therefore the number of channels) is directly affected by the modulation method of the channel. The modulation method is COFDM with either 64 or 16 state QAM (Quadrature Amplitude Modulation). In general a 64QAM channel is capable of transmitting a greater bitrate, but is more susceptible to interference.

Reception

DTTV is received via a set-top-box, or integrated receiving device, that decodes the signal received via a standard aerial. However, due to frequency planning issues, an aerial upgrade may be required if the DTT multiplexes lie outside the bandwidth of the installed aerial (quite common in the UK).

DTT Around the world

The UK leads the world in DTT uptake by the general population, using the Freeview and Top Up TV platforms. In Germany, on 4th August 2003, Berlin became the first city in the world to switch off its analogue broadcast signal and transfer completely to digital TV.

See also : Digital television

de:DVB-T fr:Télévision numérique terrestre