ISDB

Integrated Services Digital Broadcasting (ISDB) is the Japanese standard for the broadcasting of digital television over all broadcasting media. ISDB includes:

• ISDB-C, for digital cable television,
• ISDB-S, for digital satellite television,
• ISDB-T, for digital terrestrial television.

ISDB can be used for Standard Definition TV (SDTV) as well as for High Definition TV (HDTV) with multichannel digital sound and an enhanced teletext version. ISDB can be watched on an ordinary “analogue televison” through the use of a so-called set-top-box. This is a receiver which translates the incoming digital signal in a analogue signal format for the ordinary television set. Eventually, the digital receiver will be integrated in the television.

Just as the European DVB system, is ISDB- based on the transmission of MPEG-2 data containers. These containers can carry a flexible combination of MPEG-2 video, audio and other data services. The container can contain more than one program as well as data services. The data of the different programs are combined in a so-called multiplex. Each container carries Service Information (SI) which gives details about the programmes being broadcast.

The standars for the different media differ in the way the data containers are transmitted. The transmission is optimized for the transmission medium. The amount of error correction is also different for the various media.

ISDB-C and ISDB-S are based on the transmission of a single carrier on which the data is modulated with QPSK or 8PSK for ISDB-S or with 64QAM in the case of ISDB-C. ISDB-T is, just like DVB-T, based on OFDM transmission of a number of carriers.