New codecs that deliver better sound, hybrid slide show innovations, and more countries broadcasting in DRM were some of the latest developments presented by the Digital Radio Mondiale group at last week’s Digital Broadcasting Symposium in Kuala Lumpur.
Lindsay Cornell (pictured) explained the latest development in hybrid radio, which now enables RDS, slide shows and other program service information to be compatible across different standards. This will bring benefits for both receiver manufacturers and audiences.
“This new evolution allows for more modern presentation of slideshow material, to make it feel more like the experience that audiences have when using phone apps,” said Cornell.
“We have developed a standard framework so that all devices will know how to use the slides, it will now be up to broadcasters to decide how they want to use it.”
Cornell also explained COFDM, the system used to overcome multipath distortion. “It interleaves the signals to compensate for the distortion. We add extra data in the beginning because we know we are going to lose some along the way, then we can get the original quality signal back.”
Echoing a common message from all digital radio speakers, Ruxandra Obreja told engineers and managers from Asian broadcast stations that radio must be digital. “Radio cannot stay analog. Whatever platform you choose doesn’t matter, it only matters that you deliver better quality and more features to the listener,” she said.
Obreja highlighted some of the new developments for DRM since last year, including being awarded an ITU Diploma for activities in the developing world to assist in emergency broadcasting.
Fraunhofer’s Alex Zink (right) explained the features of DRM that can be used by emergency agencies during disasters. This includes the ability to wake up the receiver, tune it to the emergency channel and turn up the volume when emergency warnings are needed. Screen enabled receivers can also display emergency graphics.
India remains DRMs key market, with the adoption of DRM by All India Radio in several transmission locations.
“We are hearing a lot about the Phase 3 FM roll out in India, but did you know there is also a digital DRM rollout. 36 transmitters should be ready by July 2015… When phase 1 of the DRM roll out is complete there will be digital radio coverage across 50% of the country,” said Obreja.
In other developments, DRM was invited to hold a workshop (March 10th) at Vietnam’s national broadcaster VoV .
In Indonesia, RRI will organize a broadcast trail and workshop in the week of March 23. “Indonesia is an important market in Asia and we will see how DRM can meet their needs,” said Obreja.
Russia is also continuing to test and use DRM and two DRM digital radio channels are on air in Pretoria South Africa.
Transmission of Radio Pulpit on 1440 kHz, and a second channel on the same frequency carrying BBC World Service, began in Pretoria on 1st February. It includes DRM text messaging, Journaline and RSS feeds.
Addressing the question of whether there are enough different types of receivers at a range of price points, Obreja told delegates “chipset manufacturers are getting more agnostic.”
“There are now multi-standard chip sets and we hope these will result in multi standard receivers in the future.”
The first mass market DRM receiver is the AVION, which is going into commercial production in India this month. It has a screen, provides the full range of DRM features and emergency warning functions.
Addressing one of the technical reasons why broadcasters should go digital with DRM, Alex Zink explained that DRM is a standard that can broadcast on all existing bands, so less spectrum and infrastructure is needed to get it to air.
Audio quality in DRM has also improved with the introduction of MPEG xHE-AAC to the DRM system specification, replacing the speech-only codecs HVXC and CELP. This codec allows more services to be broadcast in a single transmission signal and aligns with the latest technology for mobile phones
Audio comparisons were played to attendees of a Thursday afternoon DRM workshop, demonstrating the much improved sound quality, even at low bit rates.
Ampegon’s Peter Streader explained the transmission properties of DRM, emphasizing the significant savings that can be obtained by DRM’s reduced energy consumption and reduced cooling needs. To achieve maximum energy efficiency “the whole system matters,” said Streader, giving an example of a coverage area that required 142 kW of power to transmit one AM service, while a DRM transmitter covering the same coverage area only required 50 kW power and could deliver three services on the same frequency.