Digital Audio Broadcasting - DAB - Digital Video and Audio Broadcasting Technology - page 464

current content transmitted. In DAB, the modulation method is COFDM
with /4-shift DQPSK. DVB uses single-carrier transmission or COFDM
depending on transmission path. DAB is intended for terrestrial applica-
tions whereas DVB provides terrestrial, cable and satellite transmission
standards. Satellite transmission is provided for in DAB but currently not
used.

“Digital Radio 1“ Ensemble

“P1“ “BR1“ “BR3“ “P2“ Services

Service
components

Audio
1

Audio
2

Data
1

Audio
3

Data
2

Audio
4

Common
Interleaved
Frame

…

SC1 SC2 SC3 SC4 SC5 SC6 SC32

SC = subchannel (capacity = n * 8 kbit/s per subchannel)

Fig. 26.4. DAB ensemble

26.2 An Overview of DAB

The following sections will provide a brief overview of DAB - Digital Au-
dio Broadcasting. The DAB Standard is the ETSI Standard ETS300401.
In the Standard, the data structure, the FEC and the COFDM modulation
of the DAB Standard is described. In addition, the ETI (Ensemble Trans-
port Interface) supply signal is described in ETS300799, and in
ETS300797 the supply signals for the ensemble multiplexer STI (Service
Transport Interface) are described. A further important document is
TR101496 which contains guidelines and rules for the implementation and
operation of DAB. Furthermore, ETS301234 describes how multimedia
objects (data broadcasting) can be transmitted in DAB.
Fig. 26.4. shows an example of the composition of a multiplexed DAB
data stream. The term "Ensemble" covers several programs which are