Alan Hughes discusses changes to DAB + Data Rates
ABC / SBS Data rate
About 18you In June, the quality of the ABC / SBS DAB + digital radio signal will be changed.
ABC Classic has been increased from 80 kbit / s to 120 kbit / s. After all the initial complaints about sound quality, many of which were unjustified, it will be interesting to see if anyone notices.
ABC Jazz is slightly increased to 88 kbit / s, which is unlikely to make a noticeable difference.
The losers were ABC state,, triple j and triple j Excavated which are reduced from 80 kbit / s to 72 kbit / s. This is interesting because the younger audience of the triple j should have better hearing.
ABC Kids Listen it has also been reduced from 72 to 64 kbit / s.
The local ABC radio for each capital city still broadcasts at 64 kbit / s, which has changed from two-channel to parametric stereo, although their AM transmitter broadcasts in mono, with the exception of Darwin, which is in FM stereo.
SBS is unchanged, which means that their Cold and Pop Asia are still 72 kbit / s stereo. Only programs of 40 kbit / s are used for ABC and SBS speech.
Community television broadcasters are preferably 48 or 64 kbit / s.
Commercial radio data in general, it focused on the quantity of different programs compared to the quality.
South Cross Austereo make all their many programs 32 kbit / s using parametric stereo.
Parametric stereo it can be likened to FM stereo coding, where a mono signal is transmitted, but also a little additional information is sent to make the stereo information (L + R, LR in FM term). Other national networks as well 6IX are 48 kbit / s stereo each.
The cost of broadcasting
One ABC / SBS DAB + transmitter carries 18 programs. DAB + commercial / community transmitters carry up to 32 programs, making it the cheapest and least polluting way to move sound from a microphone to the listener’s speaker.
Streaming over a mobile phone and NBN networks means that each listener will have to receive their own signal, much more expensive and polluting. If transmitters are not used, there will have to be many more transceivers in cell phone towers that will require more spectrum to be purchased from ACMA.
Telecommunications companies will charge all listeners for this through increased prices. NBN will also need more optical connections between PBXs and operators.
How to reduce the cost of regional broadcasting
For the districts of the country there is 1 DRM band, which covers a much larger area than DAB + and a larger area than FM. A DRM transmitter can carry both commercial programs in better quality than now.
There is data capacity for a slideshow ad, an indexed text service that includes photos called Journaline.
This will reduce transmission costs, especially for those with an AM transmitter. ABC / SBS can also use DRM 1 for bandwidth to transmit all 18 programs using 6 channels per transmitter in each country. There is an emergency warning function, as those who are in the emergency zone can wake up the radio, tune it to the emergency channel, wake up potential victims and give a message. It can also display maps and detailed instructions, as well as redirect vehicle navigation systems around police closed roads.
DAB + has only 8 broadcast channels available in Australia, the rest are used by television, while there are 206 bands 1 DRM. This means that there are enough channels to install DRM on the existing towers of the FM transmitter.
There are now single-chip digital receivers that will receive DAB + and DRM on the overseas market.
About the author
Alan Hughes is a technical author who has taught technologists for 20 years.