DVB-T: The COFDM-based system for terrestrial television

In early 1996, the European DVB (Digital Video Broadcasting) Project finalised what is now called the 'common 2k/8k specification' for terrestrial television transmission. This specification is an important cornerstone of digital video broadcasting in Europe and numerous other countries in the world. Called DVB-T, it is based on the channel-coding algorithms the DVB Project had earlier devised for digital television on cable and satellite. The modulation scheme that is used for DVB-T is OFDM (orthogonal frequency division multiplexing), which when used in conjunction with channel coding is known as COFDM. Two variants are described, one employing 1705 individual carriers in an 8 MHz channel ('2k variant'), the other employing 6817 carriers ('8k variant'). Each individual carrier can be modulated either by QPSK, 16-QAM, 64-QAM or hierarchical modulation.