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6 DAB radio
6.1 What is DAB+?
DAB+ is a new digital format through which crystal clear sound with no noise can be heard. Contrary to
conventional analogue radio transmitters, with DAB multiple stations are transmitted on one and the same
frequency. This is referred to as an ensemble or multiplex. An ensemble is comprised of the radio station, as well
as several service components or data services, which are broadcast individually by the radio stations. For further
information go to www.dabplus.de or www.dabplus.ch.
6.1.1 Data compression
With this, digital radio takes advantage of the properties of human hearing. The human ear does not perceive
sounds which are found under a specific minimum volume. Data which are found under the so-called audibility
threshold can, therefore, be filtered out. This is possible because, in a digital data stream, the relevant relative
volume for other units is saved for every unit of information. Moreover, in an audio signal, the quieter parts are
superimposed by louder ones at a specific limit value. All audio information in a piece of music that is below the
so-called listening threshold can be filtered out of the transmitted signal. This leads to data reduction in the data
stream being transmitted, with no perceptible difference in sound for the listener (HE AAC v2 process as
a supplementary codification process for DAB+).
6.1.2 Audio stream
With digital radio, audio streams are continuous data streams which contain the MPEG 1 audio layer 2 frames
and thereby represent acoustic information. This enables standard radio channels to be broadcast and listened to
on the receiver side.
Digital radio provides you not only with excellent sound quality radio but also additional information. This could
relate to the channel currently being broadcast (DLS e.g. track, artist) or be independent of this (e.g. news,
weather, traffic, tips).
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