Digital Radio Mondiale

Categories: International broadcasting | Digital radio

Digital Radio Mondiale (DRM) is an international non-profit consortium committed to designing and implementing an open-source platform for digital radio broadcasting around the world, especially on shortwave. Unlike most other DAB systems, DRM uses IBOC technology and can operate in a hybrid mode called Single Channel Simulcast, simulcasting both analog signal and digital signal.

[edit]

Advantages of DRM Technology

The main advantage of such digital broadcasting is that it yields sound quality comparable to FM, but over shortwave distances. As a digital medium, DRM can also transmit other digital data besides digitized music, including text, pictures, and computer programs (datacasting) — as well as RDS-type metadata or program-associated data like DAB does. DRM has been designed especially to use older transmitters designed for audio AM, so major new investments are not required for early adopters. The encoding and decoding can be performed with digital signal processing, so that small computers added to a conventional transmitter and receiver can perform the rather complex encoding and decoding.

[edit]

DRM as an international standard

The organization has recently received approval for the AM standard from the IEC, and the ITU has approved its use in most of the world. Approval for the Americas (ITU region 2) is pending amendments to other existing international agreements. The inaugural broadcast took place on June 16, 2003, in Geneva, Switzerland, at the ITU's annual World Radio Conference.

[edit]

DRM's CODEC technology

DRM's system uses the MPEG-4 based standard aacPlus to encode the audio and CELP or HVXC for speech programs.

All codecs can optionally be combined with Spectral Band Replication.

The resulting low-bitrate digital information is modulated using COFDM. It can run in simulcast mode by switching between DRM and AM, and it is also prepared for linking to other alternatives (e.g. DAB or FM services). DRM has been tested successfully on shortwave, mediumwave (with 9 as well as 10 kHz channel spacing) and longwave.

[edit]

DRM for FM Radio DAB

While DRM currently covers the broadcasting bands below 30 MHz, the DRM consortium voted in March 2005 to begin the process of extending the system to the broadcasting bands up to 120 MHz. DRM Plus will be the name of this technology. The design, development and testing phases of DRM’s extension, which are being conducted by the DRM consortium, are expected to be completed by 2007-2009.


[edit]

External links

[edit]

DRM in general

[edit]

DRM radio stations

[edit]

DRM radio techniques

[edit]

DRM's COFDM

[edit]

Index

de:Digital Radio Mondiale fr:Digital Radio Mondiale it:Digital Radio Mondiale nl:Digital Radio Mondiale fi:Digital Radio Mondiale sv:Digital Radio Mondiale