DAB Digital Radio Explained
What is DAB digital radio?
Digital Audio Broadcasting is a new transmission system bringing the benefits of digital to the world of radio.
The main benefits to the DAB listener:
The robust nature of DAB transmissions almost completely eradicates the problem of the hiss and fade that can spoil analogue radio transmissions. This is particularly good news for listeners to BBC Radio Five Live who can now hear the latest news and sport without all the usual problems associated with Medium Wave reception.
DAB signals are also far less likely to be affected by adverse weather conditions or local sources of interference - like pirate radio stations.
DAB technology allows broadcasters to transmit far more radio stations within the same comparable amount of radio spectrum compared to FM. It was this extra capacity that allowed the BBC to launch the five 'digital only' services in 2002 - in addition to our established stations: BBC Radio 1 to 5 as well as the BBC World Service. The flexible nature of national DAB radio mutliplex means that the BBC can create secondary services - allowing them to offer Radio 4's Long Wave content in digital clarity, and double the capacity of Radio Five Live with its sister channel; Five Live Sports Extra.
As well as music and speech - DAB transmissions also contain data information. A DAB set utilises a screen, on which various kinds of information can be displayed.
Who invented DAB?
Digital Audio Broadcasting or 'DAB digital radio' has been developed by a consortium of manufacturers and broadcasters. The BBC pioneered DAB digital radio and was the first broadcaster in the UK to build a transmission network and start broadcasting DAB in 1995.
How does it work?
Put simply - DAB radio works by utilising both MPEG and COFDM (Coded Orthogonal Frequency Division Multiplex) technology which converts the music or speech from analogue signal into digital (binary) code. This vastly reduces the potential for the broadcast to be corrupted during transmission by weather conditions, and other problems that can degrade the quality of reception.
How is this different from FM?
The 'multipath' interference which disturbs FM reception (caused by radio signals bouncing off buildings and hills) is eliminated in DAB. Digital radio sets have processors which filter out interference and correct signal errors. Digital radio is designed to use 'multipath' to its advantage. DAB technology allows the receiver to combine delayed signals, making for a more robust reception overall.
Digital radio text & data:
Have you ever heard a song on the radio and wanted to know who it is by or what it's called, or tuned into speech radio and wanted to know what the programme is about or who is speaking?
DAB digital radio sets come equipped with a small screen which carries information about the programme you're listening to. This may be a plot summary to a play, the name of the track currently being played, email addresses, up to the minute sports results or competition details.
Some stations also scroll news headlines and other up-to-date information. It is anticipated that this service will develop even further in time - providing free, useful information and Electronic Programme Guides (EPG) to make listening to DAB radio an even better experience.
