DRM – The Future?

DRM supports a range of audio content, including multi-lingual speech and music. Data and text can be carried to give computer-based readers a “web-feel”. You will need a special receiver to see all this and with tens of millions of short-wave radios around the world, it will need strong PR to get traditionalists to ditch the old kit. There is a part of me that thinks that this technology will be too expensive for SW’s core audience but change we must.

But DRM can use existing AM broadcast frequency bands. The signal is designed to fit in with the existing AM broadcast band plan, based on region.

Accountants will be pleased to know many existing AM transmitters can be easily modified to carry DRM signals…

Merging technologies will mean DRM could be a part of future personal computing products but how good will the receivers be? Remember the scanner market when we were told the whip antenna that came with it was good to long-wave…

The DRM system like DAB, uses a type of transmission called COFDM (Coded Orthogonal Frequency Division Multiplex). This means that all the data, produced from the digitally encoded audio and associated data signals, is shared out for transmission across a large number of closely spaced carriers. All of these carriers are contained within the allotted transmission channel. The DRM system is designed so that the number of carriers can be varied, depending on factors such as the allotted channel bandwidth and degree of robustness required.

The DRM system can use three different types of audio coding, depending on content. MPEG4 AAC audio coding, augmented by SBR bandwidth extension, is used as a general-purpose audio coder and provides the highest quality. MPEG4 CELP speech coding is used for high quality speech coding where there is no musical content. HVXC speech coding can be used to provide a very low bit-rate speech coder.

Here’s hoping…