ASIA-PACIFIC BROADCASTING

ISDB-Tmm technology is said to be highly compatible with ISDB-T, which is the standard for the Japanese terrestrial digital broadcasting that was deployed in 2003.

This technology is actively promoted by the ISDB-T Multimedia Forum, a group made up of approximately 80 Japanese corporations — another compelling reason why the use of ISDB-Tmm technology for broadcasting will become a reality next year.

The forum said with regards to the application of ISDB-Tmm for multimedia broadcasting, nationwide broadcasting is scheduled to use 207.5-222MHz, while VHF band 90-108MHz will be used for regional broadcasting.

Also adopted for nationwide broadcasting is MediaFLO while ISDB-TSB has been chosen for regional broadcasting. ISDB-TSB is highly compatible with ISDB-T and ISDB-Tmm, making it possible to broadcast over a narrow bandwidth.

ISDB-T, ISDB-Tmm and ISDB-TSB standards were developed with the same technology to form the “ISDB-T family”.

ISDB-Tmm eliminates the need for a guard band by combining some blocks of 13 segments (approximately 5.6MHz) and several 1 segments (1 segment = approximately 0.4MHz), and can be applied to various different bands of frequency.

In preparation for the start of ISDB-Tmm, a transmitter capable of transmitting a combination of 33 segments (14.2MHz) has already been developed. This device can fully handle the frequency band (14.5MHz) specified for mobile multimedia broadcasting, thereby significantly reducing transmission costs.

The ISDB-T Multimedia Forum added that the versatility of ISDB-Tmm enables it to be flexibly applied to a wide range of operating frequency bands, as well as support spectrum allocations for 7MHz and 8MHz bands.

Furthermore, ISDB-Tmm is highly compatible with the format used for the existing digital terrestrial TV (ISDB-T) systems.

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