Arcam DiVA DT81 Handboek - Pagina 9

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Troubleshooting

1. Display shows 'Service not found' when attempting to

This can happen when the tuner has an ensemble stored that is

no longer available. For example when the tuner is ﬁ rst shipped

it has the BBC ensemble stored, and if it is used in another

country then that ensemble will not be available. In this situation

one should perform a search.

Note that re-conﬁ guration of services within an ensemble is

handled without having to perform a search, so if services

are added or removed from the ensemble it is not necessary

to perform a search. Therefore 'Service not found' may also

appear when an attempt is made to select a service that has

been removed from the ensemble. Normally redundant services

are automatically removed from the list but occasionally they

are not. If this happens, simply select another active service

to remove redundant services fom the list of available services

and from any stored presets.

The other situation when the tuner may fail to select a service

is when the signal strength is insufﬁ cient. When a service is not

selected it is possible to view the signal strength in Engineering

Mode (provided an attempt has been made to select a service

from the required ensemble) . Generally the meter needs to be

past the 'E' in 'Strength' for reliable reception.

We strongly recommend that an external aerial is used for the

best possible performance. If the signal strength is marginal

then an indoor aerial will only work some of the time, as the

signal quality is affected by weather and the time of day.

Note: There will be situations where some ensembles are

strong and others are weak. With a good aerial you may be

able to weakly pick up some ensembles from outside their

normal coverage range.

2. Display shows 'No Signal'

This message is displayed if a signal at the required frequency

is missing. Note that it may take some time (about one minute)

to show the message. If you have removed the aerial and this

message appears, reconnect the aerial and reselect a service

to restore operation.

3. Display shows 'No services stored' at the end of the

This will happen when the signal strength is insufﬁ cient due to

either a poor aerial or lack of an available DAB signal.

4. Audio is lost and display shows 'signal weak – muted'

This happens when the signal becomes weak. A better aerial

is required.

5. Audio is lost and display shows 'Service ended' or

This occurs if the selected service is no longer broadcast – in

practice this will rarely happen. Select another active service.

6. Display shows 'No service stored' when a preset

This message is shown if a service has not been assigned to

a preset button or if that service has been removed from the

ensemble, even temporarily. If ensemble components are only

partially detected (due to weak signal strength) then the tuner

sometimes decides that a service has been removed and the

preset is deleted.

select a service

'Arcam DAB Tuner'

button is pressed

Notes on data rate and sound quality

The tuner supports MPEG audio data rates up to 256 kb/s

which is the maximum rate as deﬁ ned by the ETSI speciﬁ cation

for DAB radio.

Data rates transmitted are generally lower than this because

broadcasters prefer to include a high number of services within

the available bandwidth. Higher compression factors are used

to lower data rates, reducing audio quality.

Most stereo services operate at 192kb/s at present, and this

has been found to give very high quality audio (though 256kb/s

is even better).

Some speech-based services use mono in order to reduce

the data rate and some apply higher compression as well. It

is also common to ﬁ nd that different services have different

audio quality even though they operate at the same data rate.

This is due to differences in the audio processing techniques

used in the transmission chain. Generally speaking, audio

is transmitted without applying dynamic range compression

(DRC) – unlike FM broadcasts. DAB uses a system whereby

the coefﬁ cients for DRC are transmitted separately, so that

the tuner can apply the compression itself. This is beneﬁ cial

because the listener can decide whether or not to apply DRC:

most hi-ﬁ enthusiasts do not. However some DAB broadcasts

have some form of DRC applied directly to the audio and this

generally impairs audio quality.

DT81