Digital Radio - Overview of systems and distribution platforms

At a time when digital is supplanting analog in all image and sound transfer techniques, the sound broadcasting sector is a rather special case, insofar as the two modes seem to have found a state of equilibrium in cohabitation. Having taken the gamble that analog cannot endure in the face of the inescapable thrust of digital, this article is the first in a major dossier devoted to the relative prospects for the evolution of an exclusively digital radio.

This dossier concerns only the last segment of a radio production-distribution chain, which runs from a point of transmission to the receiving terminal, and constitutes the "secondary distribution" segment.

After a brief history of radio, this article looks at the technical platforms and networks that can be used for analog and then digital radio. The article then presents a brief overview of the technical systems developed for the secondary distribution of digital radio (by broadcast or distribution via telecom networks) and compares their different uses according to the distribution platforms.

This dossier includes three other articles:

• [TE 6 142] , which presents the main techniques common to the various digital radio systems: audio coding (in particular MPEG-4 HE-AAC), data protection and OFDM modulation;

• [TE 6 144] , which details the first broadcast standard developed, DAB (Digital Audio Broadcasting) and its 2nd generation, DAB+, as well as T-DMB (Terrestrial – Digital Multimedia Broadcasting), derived from DAB, but extended to broadcast video to mobiles;

• [TE 6 146] , which showcases other digital radio broadcasting systems via other technical platforms and networks:

  • DRM (Digital Radio Mondiale) and DRM+,

  • simulcast HD Radio,

  • satellite radio,

  • radio integrated with DVB (Digital Video Broadcasting) ;

• radio distribution via telecom networks, in particular the Internet and mobile networks....