Grundig Digital Radio User Manual
DIGITAL RADIO GUIDE
WHAT IS DIGITAL RADIO?
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What is Digital Radio?
Since the early days of broadcasting, analogue systems have been used to carry
programmes from the studios to the listeners. Now, due to the growing number of
broadcasters and programme services, the frequency bands allocated to AM and FM
radio in many regions of the world are full. The resulting congestion in the radio spectrum
has led to a decline in reception quality and is a real constraint to further growth.
Furthermore, in densely populated areas, FM reception on car radios and portables can
be very poor. This is due to the effect of severe multipath propagation caused by signal
reflections and shadowing due to high buildings.
programmes from the studios to the listeners. Now, due to the growing number of
broadcasters and programme services, the frequency bands allocated to AM and FM
radio in many regions of the world are full. The resulting congestion in the radio spectrum
has led to a decline in reception quality and is a real constraint to further growth.
Furthermore, in densely populated areas, FM reception on car radios and portables can
be very poor. This is due to the effect of severe multipath propagation caused by signal
reflections and shadowing due to high buildings.
Digital transmission technology can offer much improved coverage and availability. It is
expected to replace analogue transmissions in many areas, but as digital systems are
incompatible with current AM and FM broadcasting systems, new receivers will be
needed.
expected to replace analogue transmissions in many areas, but as digital systems are
incompatible with current AM and FM broadcasting systems, new receivers will be
needed.
In basic form, digital radio is an application of the technology in which sound is processed
and transmitted as a stream of binary digits. The principle of using digital technology for
audio transmission is not new, but early systems used for terrestrial television sound
(such as NICAM 728) need considerable bandwidth and use the RF spectrum inefficiently,
by comparison with today’s digital systems.
and transmitted as a stream of binary digits. The principle of using digital technology for
audio transmission is not new, but early systems used for terrestrial television sound
(such as NICAM 728) need considerable bandwidth and use the RF spectrum inefficiently,
by comparison with today’s digital systems.
The development of digital radio has been helped by the rapid progress that has been
made in digital coding techniques used in RF and audio systems. This has led to
improved spectrum efficiency, more channel capacity, or a combination of these benefits.
Digital compression techniques used in audio systems have improved sound quality at
low bit rates to the extent that radio broadcasts can be made on location and then
transmitted to the broadcaster’s production studios over telephone circuits in high quality.
made in digital coding techniques used in RF and audio systems. This has led to
improved spectrum efficiency, more channel capacity, or a combination of these benefits.
Digital compression techniques used in audio systems have improved sound quality at
low bit rates to the extent that radio broadcasts can be made on location and then
transmitted to the broadcaster’s production studios over telephone circuits in high quality.
Ideally, to reach the widest range of listeners, a genuinely universal digital radio system
should be capable of being transmitted via terrestrial, satellite and cable systems.
should be capable of being transmitted via terrestrial, satellite and cable systems.
There are new digital radio systems in operation. The list is set out in Table 2.1.
The table illustrates the wide spread of operational systems throughout the world.
The great strength of the present analogue transmission systems is the world-wide
standardisation on just two systems (FM and AM). This enables listeners to use one radio
to receive programmes at any location. But in the development of digital systems, it is
now clear that similar standardisation will not be so easily achieved. Differing market
requirements are driving digital systems to be more specialised and tailored to meet
regional, national, or application-oriented needs. Furthermore, the complexity of digital
systems compared to existing analogue techniques fosters this differentiation.
standardisation on just two systems (FM and AM). This enables listeners to use one radio
to receive programmes at any location. But in the development of digital systems, it is
now clear that similar standardisation will not be so easily achieved. Differing market
requirements are driving digital systems to be more specialised and tailored to meet
regional, national, or application-oriented needs. Furthermore, the complexity of digital
systems compared to existing analogue techniques fosters this differentiation.