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Is DMB a totally different technology to DAB?

Posted on Wednesday, December 5th, 2007 at 12:47am. #

Michael Mullane posts an inexplicable personal blog about DAB in France.

In it, he posts:

If you build a network capable of transmitting DMB audio, it is easy to convert it to deliver DMB video. However, if you build a DAB+ network, there is no migration path to the brave new world of multimedia services.

Wrong. 100% wrong. Both DMB and DAB+ (and DAB, for that matter) use the same network. No, there’s no difference in the transmitters or frequencies at all. If you wanted to, you could broadcast DMB, DAB+ and DAB in the same multiplex, using the same transmitter. Far from being “no migration path”, the migration path is built-in: because it’s the same thing. A DMB receiver would pick up all DMB, DAB+ and DAB transmissions - indeed, I’ve got one, which I’ve used successfully to pick up DMB and DAB transmissions. That’s it up there - picking up a DMB channel in Munich. And follow this link to see the same radio picking up DAB radio, in Norway. With multimedia content, dare I say.

Mike then goes on:

But perhaps the French are the ones who are seeing furthest into the future. … Different choices - T-DMB or DAB+ - may be appropriate in different countries.

Again, the opposite really ought to be true. “Standards” are there for a good reason - to standardise the way we do things, and benefit from globalisation. Arguably, the lack of a common standard has harmed DAB. The “oooh, but DAB+ is just around the corner, shouldn’t we just wait?” countries are procrastinators. The DRM Radio people are confusing the world yet further, with another competing technology. And then, there’s iBiquity’s HD Radio, which adds further complication (and there’s a broadcaster in Switzerland using HD Radio, incidentally). Will we ever get a digital radio into a mobile phone (built for a global market) or a car (built for a global market) when there’s all this local complication?

Putting aside the DAB+/DAB argument for a minute (it’s highly likely that new radios next year will be upgradeable anyway), the last thing that France needs is a ‘new’ digital radio technology; and, confusingly, audio-only DMB broadcasting is not even in the DMB specification, so not only will they be broadcasting something for which they’ll have no receivers, they’ll also be broadcasting out of spec audio, which is a little odd. Nick Piggott raises another point - “DMB Audio” means that cheap radios (the most important consumer driver is price) will be virtually impossible to build.

Different choices may be appropriate in different continents. But frankly, we need a European-wide solution to digital radio broadcasting - and a relevant broadcasting body to advise broadcasters and countries on the best option. France’s bizarre audio-DMB plan is madness: Mike Mullane’s assertions are curiously wrong. Which is a shame, because the last I saw him, he was buying me a beer at the top of a hotel in Singapore, so he can’t be that mad really.

3 comments

Mike said at December 5th, 2007 at 11:20am

Isn’t the “cultural” difference in France actually the one that Mike Mullane mentions in his blog - French broadcasters don’t want to provide more choice to listeners. UK (commercial) broadcasters were very interested in a DAB system because in the DAB world they can increase their market share against the BBC. French broadcasters are happy with the status quo, plus tyhe ability to offer data services on top. (Plus, they are French, and going it alone and not giving in to the Anglo-Saxons is in their blood…)

MM said at December 6th, 2007 at 10:55am

The key point is that T-DMB is less spectrum efficient than DAB+ . In addition, French radios will need a lot of bits to provide the kind of interactive and video services they are planning. For the sake of argument, if a multiplex is providing 50 DAB+ services, it will not be possible to migrate to 50 DMB services.

Incidentally, more details about France’s digital strategy are available at http://www.culture.gouv.fr/culture/actualites/conferen/albanel/radionum.htm

James Cridland said at December 6th, 2007 at 8:21pm

(A fair key point, MM. But the post is actually saying that the networks cannot be upgraded, and doesn’t talk about filling multiplexes totally and swapping like with like.)

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