Digital Basics

What is digital radio?



Digital radio is a new way of transmitting radio signals that brings with it a host of exciting features and added value to the listening experience. Because it uses radio spectrum more efficiently, digital radio offers a number of advantages over traditional analogue radio.

Digital radio is different to AM and FM radio as, instead of the audio directly modulating the radio signal, the audio is first digitised and it is the resulting digital data that modulates the radio signal. Digital radio signals are far less likely to be affected by adverse weather conditions, local sources of interference or degradation due to multipath reception.



Why move to digital?


Beyond the promise of better reception and greater clarity of audio, listeners can also access a range of new services. These include scrolling text information, program details, track listings, news headlines, and other multimedia content. Digital radio receivers also tune by station name, rather than frequency, making it easier to find favourite radio stations. Further functionality also includes audio capture built into the radio receiver enabling ‘pause’ and ‘rewind’ by the user.



How digital radio works


Digital radio works by using technology that converts music or speech from analogue signal into digital code. This reduces the potential for radio broadcasts to be corrupted during transmission by weather conditions and any other problems that degrade the quality of reception.

A digital signal also allows radio stations to deliver multimedia content alongside an audio stream. Therefore, to receive digital radio, listeners will need to purchase a specialised receiver that may include a screen. This can display a host of information such as the station name, track listings, or weather updates, for example.

The screen can display a host of information such as the station name, track listings, or weather updates, for example.
The relationship between a radio station and its listeners is also altered in a digital environment. Australia has adopted the Eureka 147 digital radio transmission standard for the initial state capital rollout. Under Eureka 147 there will no longer be a direct relationship between an individual radio station and the licensed transmitter. Instead many stations or content providers will feed through multiplexes to the same transmitter.

By contrast to analogue, radio stations operating in digital transmit a signal to a ‘multiplex’ – the transmission infrastructure for digital radio – that combines several audio channels and encodes them into a single stream. Data and other services – such as multimedia content – can then be added to form an ‘ensemble’.

Therefore, new management entities will be required to operate the digital transmit multiplexes. In addition the community broadcasting sector will require new management entities to jointly manage the provision of content.



When is digital radio being introduced?


The Federal Government has decided on a staged rollout of digital radio services, beginning in the six state capitals from 2009. As a result, the initial involvement of community broadcasters is limited to forty ‘wide-coverage’ stations. The Government hasn’t committed to a full rollout of digital radio throughout Australia.

Digital radio will supplement existing analogue radio services for a considerable period and may never be a complete replacement, according to Government policy.

In the meantime, the sector has secured digital capacity for a limited number of stations and some financial resources for an initial rollout of digital radio infrastructure.



What are the benefits of digital radio?


There are several benefits of digital radio:

1. Improved reception and sound quality:

The robust nature of digital transmission avoids many of the problems that can affect analogue, such as interference – or the hiss and crackle – of current broadcasts.

Digital signals are also far less likely to be affected by adverse weather conditions or local sources of interference – like trams and other electrically driven machines.

Sound quality is able to be ramped up to impressive quality, or ramped right down for minimal quality services. These quality parameters can be made by broadcasters on a permanent or dynamically changing basis.

2. Increased listener choices:

In the UK, digital radio technology has enabled broadcasters such as the BBC to transmit many more stations than ever before. However, because digital spectrum is currently scarce in Australia, there will be limited opportunities for large numbers of new services.

3. Easy programme selection:

Digital radio receivers also tune by station name, rather than frequency, making it easier to find favourite radio stations. Some receivers also come equipped with an Electronic Programme Guide (EPG) and hard drive, allowing listeners to easily record programmes in much the same way as digital television.

4. Other services:

The flexible nature of digital radio means that community radio stations can provide ‘secondary services’ for the listener. Digital radio receivers come equipped with a small screen which can carry information, such as programme details, the name of the track currently being played, web addresses, competition details, sports and weather, as a few examples.