z Bang & Olufsen Audio System
z Digital radio tuner
z Te l e v ision hybri d t u n e r
Self-Study Programme 366
Digital Infotainment
Audi is a name synonymous with outstanding, innovative automotive engineering. A number of brand names
spring to mind: quattro®, FSI® and MMI, the pioneering Multi Media Interface, are just a few of the many
achievements that have had a profound impact on automotive manufacturing. Once again, the brand name
Audi lives up to its slogan "Vorsprung durch Technik".
With the digital radio, the television hybrid tuner and the Bang & Olufsen Audio System, Audi offers digital
infotainment systems that represent a significant addition to the standard product package in terms of variety
and quality.
Customary ease of use
One of the outstanding features of cutting-edge technology is its ease of use. The tried and tested, and yet
still pioneering, operating concept of the MMI (Multi Media Interface) ensures maximum functionality and
ease of use thanks to its intuitive navigation technology.
The large, high-resolution screen makes for clear presentation of all operator menus in the MMI, as well as
user-friendly presentation of all relevant additional information. The digitisation of signals greatly simplifies
the handling of information: This simplifies the processing of audio and visual signals while reducing the
volume of data. Unlike analog broadcasting, digital information can be reproduced and broadcast almost
without loss of quality.
Video and audio can now be combined with textual information
Digital reception also opens up additional possibilities for information processing and distribution.
In addition to the actual broadcast content, innovative services are broadcast with digital programmes.
These are: Audio and visual signals can combined with textual information thanks to digital broadcasting.
This information can refer to current programmes such as title, artist (with DAB) and the Electronic
Programme Guide (EPG) for DVB-T.
On the other hand, the information can also be unrelated to the current programme, such as messages,
weather reports or traffic messages for DAB. These new features will make digital receivers even more
attractive in future.
This self-study programme teaches the design and function of new vehicle models,
new automotive components or new technologies.
The self-study programme is not a workshop manual!
All values given are intended as a guideline only, and refer
to the software version valid at the time of publication of the SSP.
Please refer to the relevant Service Literature for current inspection, adjustment and repair instructions.
NoteReference
Bang & Olufsen Audio System
Bang & Olufsen is a Danish manufacturer of high-end entertainment electronics.
Bang & Olufsen attaches particular importance to performance, design, human expectations and perfect
workmanship. The goal for the development of the Bang & Olufsen Advanced Sound System was to build the
best sound system ever used in a motor vehicle. This applies both to the sound and to the ease of use and the
design.
Particular attention was paid to the acoustic quality of the sound system.
A motor vehicle places special demands on a sound system. The listeners are not seated at the auditory
centre of the loudspeakers. They are seated at different distances to the loudspeakers. The loudspeaker
position is, to a large extent, predefined by the requirements relating to the occupant cell. The materials used
to build the vehicle body and interior also affect the quality of the sound system.
Acoustic lens
– 2 x 19 mm treble loudspeaker
Centre
– 70 mm centre treble loudspeaker
4
Overview of the components
The Bang & Olufsen Advanced Sound System comprises a total of 14 loudspeakers. The loudspeakers are
driven by 2 amplifiers with 14 output channels. The amplifiers have a total power output of over 1000 W.
Front doors
– 90 mm mid-range loudspeaker
– 140 mm bass loudspeaker
Rear shelf
– 200 mm long-stroke subwoofer
– 2 x 70 mm mid-range loudspeaker
Rear doors
– 25 mm treble loudspeaker
– 133 mm bass loudspeaker
Amplifier
J787 Digital sound package control unit 2
– 4 x 125 W Class D
– 1 x 250 W Class D
J525 Digital sound package control unit
– 9 x 28 W MOST DSP
366_054
5
Bang & Olufsen Audio System
Function diagram
MOST
30
31
Optical fibre break
R14R105R158R103
R164
R164
Telephone audio IN
J525
Line Out
R21
R16R106R104
R23
6
V344
30
31
Line In
J787
R157R159
R20
R22
V345
Legend
J525 Digital sound package control unit
J787 Digital sound package control unit 2
R14Rear left treble loudspeaker
R16 Rear right treble loudspeaker
R20Front left treble loudspeaker
R21Bass loudspeaker, front left
R22Front right left treble loudspeaker
R23Bass loudspeaker, front right
R103 Front left mid-range loudspeaker
R104 Front right mid-range loudspeaker
R105 Rear left mid-range loudspeaker
R160
366_001
R106 Rear right mid-range loudspeaker
R157 Subwoofer in rear shelf
R158 Mid-range/treble loudspeaker, centre
R159 Mid-range/treble loudspeaker, rear left
R160 Mid-range/treble loudspeaker, rear right
R164 Microphone unit in front roof module
V344 Front left treble loudspeaker control motor
V345 Front right treble loudspeaker control motor
7
Bang & Olufsen Audio System
Treble loudspeakers in dash panel
Two 19 mm treble loudspeakers are fitted in the
dash panel. The loudspeakers are extended by an
electric motor when the MMI is switched on.
The extended position of the loudspeaker is
monitored by an integrated Hall sender.
An integrated worm gear is used to reduce the
motor speed to the crank speed. The rotation of the
crank is translated via a connecting rod to a linear
movement of the treble loudspeaker.
If the load on the drive is too high when the treble
loudspeakers are extending, e.g. because someone
is holding on to them, the connecting rod
disengages from the crank drive. The roller on the
crank slides along the slotted connecting rod.
The worm gear is thus protected against
mechanical damage. If the treble loudspeakers are
subsequently retracted fully, the connecting rod
re-engages in the crank during this movement so
that the loudspeakers subsequently extend fully.
If an extended loudspeaker is pushed down
mechanically, e.g. by hand, the mechanism behaves
in exactly the same way. The connecting rod is
disengaged when the loudspeaker is pushed down.
If the treble loudspeaker is retracted by MMI,
the crank is moved into the lowest position and the
connecting rod re-engages.
Treble loudspeaker retracted
Loudspeaker
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Acoustic lens
An acoustic lens which provides optimal sound
radiation into the vehicle interior is attached to the
treble loudspeakers. The acoustic lens allows
optimally directed reflection of the sound into the
vehicle interior. The lens shape specially designed
for well-balanced horizontal sound distribution.
The result is much better acoustics than in a
conventional system, where the front windscreen,
among other things, acts as a sound reflector.
Con-rod
Crank
Motor
Treble loudspeaker extended
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Worm gear
Drive
8
366_008
366_015No reflection off windscreen
Integrated loudspeaker systems
All mid-range loudspeakers, bass loudspeakers and
the subwoofers are designed as fully integrated
loudspeaker systems. The housings for the
respective loudspeakers have been optimised for
minimum vibration. This prevents uncontrolled
vibration of the vehicle body and interior trim
panels. The result is enhanced sound clarity and
definition. Noise radiation away from the vehicle is
greatly reduced since the body's outer skin no
longer functions simultaneously as a loudspeaker
box.
However, due to the smaller housing volume
compared to non-integrated loudspeaker systems,
additional amplifier power is required to achieve the
same sound pressure level in each loudspeaker.
The sound pressure level is a measure of the volume
of a loudspeaker and is measured in dB ( decibels).
A 10 dB increase in sound pressure is equivalent to
doubling the volume.
Wide horizontal sound radiation
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9
Bang & Olufsen Audio System
Digital sound package control unit J525
The digital sound package control unit consists of
an audio amplifier equipped with a powerful digital
signal processor (in short: DSP).
The amplifier converts the digital stereo signal from
the MOST bus to the individual audio channels and
controls 9 loudspeakers and the digital sound
package control unit 2 J787.
In addition, the DSP adapts the audio signals to the
specific sound characteristics of the Audi A8 ‘03.
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Automatic source volume correction
Different audio sources, such as radio, CD, DAB, etc., transmit different music and voice at different volumes.
This is principally due to the fact that different radio stations broadcast their programmes at different
volumes, and because audio CDs are recorded at different volumes.
The digital signal processor in the amplifier recognises the volume and adjusts all sources in such a way that
the listener notices no change in volume after selecting a different audio source, e.g. from radio to CD.
Level
Level
10
Source 1
Source 2
Frequency
Frequency
Signal
processor
Level
Frequency
366_017
Frequency response correction
The acoustic properties of vehicle interiors are less than optimal, unlike rooms designed specially for this
purpose in buildings. To optimise in-vehicle acoustics, the digital signal processor corrects the frequency
response, i.e. bass, mid range and treble are adjusted digitally. Sound frequencies that are amplified by the
vehicle interior are output in an attenuated form by the amplifier. Sound frequencies that are heavily
attenuated by the vehicle interior are output in an amplified form. The digital signal processor also functions
as a frequency splitter.
The sounds transmissible from the respective loudspeakers are transmitted to the loudspeaker.
A treble loudspeaker receives only high frequencies, since the high energy of the low frequencies would
destroy the treble loudspeaker coil. A bass loudspeaker receives only low frequencies, since the large mass of
the loudspeaker coil would be much too slow for the transmission of high frequencies. The result for the
listener is a well-balanced auditory experience across the frequency range from very low to very high
frequencies.
Highpass filter
Treble loudspeaker
Frequency
Lowpass filter
Bass loudspeaker
Frequency
Level
Frequency
Signal
processor
Level
Level
1 attenuated frequency
2 amplified frequency
Bass and treble are also corrected digitally in the MMI and additionally in the amplifier for radio or
TV, CD, DAB.
366_018
Fabric and leather interior trims have different acoustic properties. To adapt the loudspeaker signals optimally
to the vehicle, the interior trim material can be selected in the amplifier configuration using the diagnostic
tester.
11
Bang & Olufsen Audio System
Position-dependent volume correction
The listeners are not seated in the auditory centre in the vehicle interior, i.e. equidistant from the left and right
loudspeakers. To compensate for the different distances which the sound travels from each individual
loudspeaker to the ears of the listener, the volume is corrected in the digital signal processor for each
loudspeaker.
The balance and fader settings in the MMI are also made digitally in the amplifier.
While driving, the engine, tyres and headwind,
for instance, produce background noise which
negatively affects the listening experience.
To compensate for this effect, various parameters
are monitored:
– Road speed (via MOST bus)
– Air conditioner blower speed (via MOST bus)
– Background noise via a measuring microphone
integrated in the overhead module
These parameters are used for correcting volume
and frequency response. At high ambient noise
levels, the human ear does not respond nearly as
well to low-volume music than to loud music.
To compensate for this effect, low-volume music is
amplified to a higher degree than loud music with
increasing vehicle speed. To the listener, the sound
system appears to maintain a constant volume
irrespective of the speed at which the vehicle is
travelling.
To compensate for personal listening preferences,
the volume can be equalised in a continuously
variable manner in the MMI sound menu.
Petrol and diesel engines have different acoustic
properties. Yo adapt the volume equalisation
optimally to the vehicle, the engine type is encoded
in the diagnostic tester. The variants left-hand drive
and right-hand drive or short and long wheelbase
version can be selected as coding options.
ChangerSource
CD
DSP Bang & Olufsen
Sound Set
all
Surround Level
Volume equalisation
ManualSound
366_060
13
Bang & Olufsen Audio System
Loudspeaker signal propagation time correction
A propagation time correction is made for each individual loudspeaker. This correction compensates for the
different distances which the sound travels from the individual loudspeakers to the listener's ears, producing
a "surround sound". The listener has the impression of being seated before an orchestra in the centre of a
concert hall.
Using the SOUND SET option in the MMI, the sound can be set to ALL, DRIVER, FRONT and REAR. In these MMI
settings, the DSP corrections are adapted to the respective listener's seating position. The setting adapts both
the propagation time and the volume of the loudspeaker signals. In all settings, the audio signals are output
in surround sound.
Level
Time
Signal
processor
Level
Loudspeaker 1
Time
Level
Loudspeaker 2
Time
Level
Loudspeaker 3
Time
Level
Loudspeaker 4
Time
14
366_019
Surround Level
To create a three-dimensional sound, the signals
from the loudspeakers are delayed in relation to
each other in the digital signal processor.
The surround level can be set in the MMI. When the
surround level is set to minimum, the audio signal is
output in pure stereo, i.e. undelayed. The higher the
surround level, the greater the three-dimensional
sound effect. This effect is principally achieved by
delaying the output signals of the rear loudspeakers
in relation to the signals of the front loudspeakers.
The volume of the individual loudspeaker signals
remains unchanged. The surround level therefore
has no effect on the fader setting.
Entertainment Volume Reduction
During a navigation system announcement,
the digital signal processor is capable of mixing the
announcement and the audio source (e.g. CD).
The audio source volume during the navigation
system announcement is adjustable under MMI
menu item "Entertainment Volume Reduction".
CD changerSource
ManualSound
CD
Surround Level
366_061
Output signals
The amplifier sends the signals for the treble
loudspeakers, the centre loudspeaker, the centre
bass loudspeakers and the surround loudspeakers
to the loudspeakers in an amplified form.
The signals for the bass loudspeakers and the
subwoofers are transmitted in an non-amplified and
analog form to the digital sound package control
unit 2. The non-amplified signals are ground-free
differential signals. Thus, the signals are
well-protected from external interference.
Specifications
–MOST bus interface
–2 microphone inputs
– Digital signal processor with 14 available outputs
– 9 x 28 W amplifier for mid-range, lens and
surround sound
– 5 analog outputs and serial port for J787
– High-power 32-bit signal processor
– 24-bit digital-to-analog converter
– Hardware and voltage monitoring
– Fault memory
– Diagnostic function
15
Bang & Olufsen Audio System
Digital sound package control unit 2 J787
The digital sound package control unit 2 is an
amplifier incorporating Class-D technology.
This technology makes possible a high amplifier
power output with minimum power input.
Amplifier efficiency is approx. 95 %. Only approx.
5 % of energy consumed is converted to heat.
Because waste heat is reduced to a minimum,
the vehicle's power management system works just
as efficiently despite the system's high power.
The amplifier housing requires no cooling fins
either. The waste heat from the amplifier is
dissipated only through the closed aluminium
housing. On the amplifier PCB is mounted a small
fan which circulates the air within the amplifier and
allows the complete housing to be used for heat
radiation.
366_057
Functional principle of the amplifier
The digital sound package control unit 2 J787
operates as a digital amplifier.
In analog amplifiers, the input signal is amplified by
a transistor according to the input voltage.
The transistor behaves in much the same way as a
control valve. If the valve is half open, half the
voltage is conducted to the loudspeakers. A fraction
of the voltage is lost in the valve, i.e. a fraction of
the power (= voltage drop x current) is converted to
heat. For this reason, analog amplifiers require a
large heat sink for high power outputs. This makes
the amplifier large and heavy. In addition, the high
power loss has a negative effect on power
management.
Class-D amplifiers are much more effective in this
regard. Unlike analog amplifiers, the transistors in
digital amplifiers do not work as control valves,
but as switches. When the switch is open, the full
power is output to the loudspeakers. When the
switch is closed, no power is output to the
loudspeakers. As no current flows when the switch
is closed, no power loss can occur in the amplifier.
The amplifier converts the analog input signals to
pulse-width-modulated (PWM) signals.
The analog signal is converted into a pulsed current
(square-wave signal sequence) with a much higher
frequency than the highest music tones. Pulses are
typically in the high kilohertz range.
This PWM signal is amplified so that the desired
power is available at the output. The amplified
signals are subsequently converted back to
sine-wave signals in a lowpass filter comprising
coils and capacitors in order that the required
amplified analog signals are transmitted to the
loudspeakers.
Despite the high power output, a 30A fuse
(slow blow) is adequate for the amplifiers. This low
fuse rating is achieved, among other things,
by using capacitors. Acting as energy accumulators,
the capacitors are built into the amplifier to ensure
that short bass pulses, which have a high current
demand, do not place undue strain on the onboard
power supply.
Class-D amplifiers are classed as digital amplifiers
based on their internal PWM principle. The "D" does
not stand for digital. The Class-D technology was
developed chronologically after the Class-C
technology.
16
Treble loudspeaker motor drive
The instructions to extend or retract the treble loudspeakers are sent via the serial RS232 port from the digital
sound package control unit J525 to the digital sound package control unit 2. The digital sound package
control unit 2 controls the two electric motors for extending and retracting the front treble loudspeakers.
The movement of the treble loudspeakers is monitored by a Hall sender integrated in the treble loudspeaker.
The Hall sender is evaluated in the digital sound package control unit 2. It is used for blocked motor detection.
If a blocked motor is detected, the electric motor is switched off.
Serial data interface between the amplifiers
The serial port is used for data transfer between the two amplifiers for the digital sound package.
All information, such as control commands for the treble loudspeaker motors and diagnostic information,
is transmitted along this data line. The digital sound package control unit 2 J787 does not have its own
diagnostics address word. It is diagnosed entirely via the digital sound package control unit J525.
Switching the digital sound package control unit 2 J787 ON and OFF
There is a wake-up line from the digital sound package control unit J525 to the digital sound package control
unit 2 J787. A pulsed signal is sent via this line from the digital sound package control unit J525 to the digital
sound package control unit 2 J787. As long as the level of the signal is pulsed at regular intervals, the digital
sound package control unit 2 J787 remains switched on. If the signal stays at a constant level, the digital
sound package control unit 2 J787 cuts out.
J525J787
Wake-Up
Serial
interface
Specifications
– 1 x 250 W driven through 8 ohms
(0.1 % total harmonic distortion THD) amplifier
for subwoofers
– 4 x 125 W driven through 4 ohms
(0.1 % total harmonic distortion THD) amplifier
for bass reflex loudspeakers in doors
– 115 dB dynamic range
Line InLine Out
R22R21
V344V345
–5 analog inputs
– Specially developed DC converter optimised for
authentic sound
– Intelligent drive for external acoustic lenses
366_059
17
Digital radio tuner (DAB)
DAB technology
Digital Audio Broadcasting (DAB) is a digital
transmission standard for the terrestrial reception
of radio programmes. Terrestrial means that the
transmitter aerials are located at ground level
(Latin: Terra). The aerial locations are normally used
for analog FM radio.
366_036
The audio signals are digitised before they are
transmitted and compressed into the MPEG-1 Layer
2 format. MPEG-1 Layer 2 is a compression method
very similar to the well-known MPEG-1 Layer 3,
better known under the abbreviation MP3 as a
compression format for audio files on PCs.
The MPEG-1 Layer 2 format achieves for CD quality
sound a compression rate of 6, i.e. the data volume
is one sixth of that on an audio CD. By comparison,
MP3 achieves a compression rate for CD quality
sound of approximately 10.
Both compression methods are lossey. Retrieval of
the original, uncompressed audio data from this
data is no longer possible. However, in a listening
comparison between CD audio and MPEG
compressed data with a high bitrate, no difference
is noticeable, because, in the case of similar tones
with markedly different volume levels, the human
ear picks up the louder tone only. MPEG utilises this
psychoacoustic effect by removing by removing
from the digital information the tones which are not
perceptible to the human ear.
Data volume with same sound quality
366_023
Volu me
Short, loud signal
Non-audible sounds
Frequency
366_024
DAB stations use bitrates from 32 to 256 Kbits/s.
Various stations with different bitrates can be
grouped in an ensemble. Stations which broadcast
only voice information require a low bitrate.
Stations which broadcast music in a high sound
quality require a high bitrate. The sound
characteristics of the stations differ accordingly.
18
Example: several stations from the Bavaria ensemble
StationBitrateSignalProgramme
BR Traffic
Radio
BR B5 aktuell 96 Kbits/sMonoInformation
BR
BayernMobil
Rock Antenne192 Kbits/sStereoRock Music
BR Bayern 4192 Kbits/sStereoClassical
48 Kbits/sMonoTra ve l
128 Kbits/sStereoPop Music
type
For the transmission of digital information by aerial,
several audio data streams including data services
are grouped to form an "ensemble" . An ensemble is
a group of stations which is transmitted on a single
channel. In this way, multiple stations can be
transmitted simultaneously in an ensemble until the
total bitrate of all stations reaches the maximum
total ensemble bitrate of 1.7 Mbit/s.
The ensemble is modulated by means of Coded
Orthogonal Frequency Division Multiplex (COFDM).
This method offers much better immunity to
interference than analog broadcasting. COFDM also
offers the advantage that it is possible to build a
single frequency network.
Single frequency network
MemoryBand
Update station list
Bayern
"BR B 5 aktuell" channel
BR Bayern 4
BR Bayern Mobil
BR Business
ManualSound
366_025
StationEnsemble
Channel 11B
Channel 11B
A single frequency network transmits information
through various stations to various locations on the
same channel. Each ensemble uses up only one
channel in the reception band throughout the
coverage area. As a result, a single frequency
network has several times the capacity of analog
radio. Furthermore, DAB radio mixes the signals
from the various stations to obtain better reception.
The signals follow various paths from the
transmitter antennas to the receiver, due to
reflection off buildings or natural obstacles. In the
case of analog systems such as VHF, this leads to
interference with reception while DAB also improves
reception quality by mixing.
Channel 11B
Channel 11B
366_026
366_027
19
Digital radio tuner (DAB)
DAB uses the range from 1452-1492 MHz for the
transmission of frequencies in band III
(174-230 MHz) as well as in the L band. Band III is
used for cross-regional ensembles. The L band is
used to broadcast local ensembles.
Transmission of text data
In addition to the audio data, other information,
such as radio text, is broadcast.
In analog radio systems, the station name is
stationary on the station display, unlike in RDS.
DAB also offers the "radio text" service, which
supports digital radio R147. All dynamic text
information, such as display of artist, title,
messages or other additional text information,
are broadcast through the "radio text" service.
The radio text can be selected in the MMI using the
"Manual" control key.
Band III
L band
366_034
366_021
DAB information on the Internet
The Internet offers much more information on the topic of DAB. A large amount of information in English can
be found at www.worlddab.org on the possibility for the reception of DAB in the various countries.
www.worlddab.org
This English-language web site provides a complete overview of the stations broadcast world-wide in
ensembles.In addition to this, of course, the respective operators in each country also provide information in
the respective national language.
www.wohnort.demon.co.uk/DAB/index.html
20
Digital radio R147
Integration in the MMI system
The digital radio optionally available with all MMI
systems. Even if a digital radio is available in the
vehicle, the vehicle nevertheless has an analog
radio tuner R (K Box) for FM, MW and LW. As with all
other infotainment control units, digital radio R147
is also integrated in the MOST data bus.
Update station list
TV tuner
R78
Digital radio
R147
Radio
R
366_028
Digital radio R147 is designed as a single tuner.
For this reason, there is no auto tuning function
which automatically updates the receivable
ensembles. The station list has to be updated
manually. Updating the station list can take
approximately 1 minute. In countries in which the
L band is not used (e.g. United Kingdom),
it is recommended to deactivate the L band in the
set-up. This will shorten the search time.
Station tracking
(automatic FM tuning)
The MMI system checks automatically if DAB
stations are additionally received via standard
analog radio R as FM stations. If the DAB transmit
signal received by the digital radio R147 is too weak,
the MMI system changes over immediately to the
same stations in the radio R. On the MMI display,
the changeover is indicated by an (FM) after the
station name.
MemoryBand
Radio DAB
Station list
Update station list
Bayern
BR B5 aktuell
BR Bayern 4
BR Bayern Mobil
ManualSound
366_062
MemoryBand
Radio DAB
Station list
Update station list
Bayern
BR B5 aktuell
BR Bayern 4
BR Bayern Mobil
ManualSound
366_029
21
Digital radio tuner (DAB)
The MMI system remains set to FM reception for at
least 30 seconds. This helps to avoid overly hectic
switching between tuners. Unnecessary switching
back and forth between tuners is undesirable, since
the digital signal is transmitted as an ensemble with
a delay of approx. 1 second compared to the FM
signal, due to the need for digitisation, compression
and compositing. The listener will be able to detect
the changeover between stations due to repeated or
missing words in a spoken sentence.
Radio Traffic Information
Radio Traffic Information can be activated or
deactivated in the set-up of the digital radio.
The traffic information function of the DAB station is
not used, rather the Radio Traffic Information
function of the FM station which is configured in the
radio R. The digital radio R147 in the MMI system
behaves in exactly the same way as, for example,
the CD changer or the TV tuner.
All traffic information services, such as TA, TP and
TMC, are used only by the analog radio tuner R.
Basically, DAB enables the VHF-RDS services TA
(=Traffic Announcement) and TMC (= Traffic
Message Channel) to be used digitally. Not all radio
stations make use of these services, which means
that, in practice, FM stations provide more
comprehensive coverage for car drivers.
Reception level
good
poor
Radio source
366_031
Setup Radio DABSettings
Radio Traffic
Information
Station tracking
ON
ON
ON
L band
PTY Filter
Clear memory
DisplaySound
366_035
Installation location
The digital radio R147 is installed in the vehicle rear
end adjacent the other Infotainment components.
In the Audi A8, the digital radio is attached to the
mounting plate adjacent the K box as shown.
In the Audi A6 the digital radio is also installed in
the vehicle rear end on the left-hand side.
In the Audi Q7, on the other and, the digital radio is
installed on the right-hand side.
366_013
22
Function diagram
The digital radio R147 receives its power supply via
terminals 30 and 31. As a control unit integrated in
the MOST optical fibre circuit, it has an optical
MOST terminal, as well as a line for optical fibre
break diagnostics of the MOST control units.
The aerial lead is connected to the control unit by a
black FaKra connector.
Legend
R24Aerial amplifier
R147 Digital radio
Aerial
In the Audi A8, a DAB amplifier has been added to
the aerial amplifier R24.
The aerial module with integrated DAB amplifier can
be identified by the black FaKra connector.
30
31
Optical fibre
MOST
break
R147
Illustration: side window with aerial?
DAB aerial
R24
366_010
366_032
In the Audi A6 Avant and in the Audi Q7, the aerial is
integrated in a side window. The associated aerial
amplifier is installed directly adjacent, and likewise
has a black FaKra connector.
Coding
The country configuration "Canada" can be
encoded. In Canada, DAB is likewise transmitted in
the L band frequency range (approx. 1.4 GHz).
However, different frequency intervals are used
between the individual channels. If the digital radio
R147 is encoded incorrectly, reception in the 1.4 GHz
range will be affected.
23
TV hybrid tuner (analog and DVB-T)
DVB-T technology
DVB-T is the abbreviation for Digital Video
Broadcasting-Terrestrial and is the terrestrial variant
of digital television. In addition to this terrestrial
variant, there is also DVB-S for digital satellite
television and DVB-C for digital cable television.
In the case of DVB-T, the audio and visual signals are
compressed in accordance with the MPEG-2
standard and transmitted in the form of data
packets. MPEG-2 is also used for data compression
for DVDs. However, this does not mean that DVB-T is
broadcast in DVD quality. The MPEG-2 technology is
newer than the MPEG-1 technology, which is used
for DAB. MPEG-2 is specially designed for the
compression of video, i.e. relatively large volumes of
data.
As with DAB, the information modulated using
COFDM (Coded Orthogonal Frequency Division
Multiplex). The arguments in favour of CODFM are
the same as for DAB, the digital radio: immunity to
interference, the possibility for the use of a channelsaving single frequency network to broadcast
programmes and suitability for data transmission to
moving receivers, e.g. vehicles. CODFM provides
reliable signal transmission with a good level of
resistance to interference and reflection.
Data can be transferred at a bitrate of 5 to 32 Mbit//s
per channel. This is sufficient to broadcast 4 TV
programmes. A group of programmes which can be
broadcast over one channel is also referred to as a
"bouquet".
Picture quality similar to that of analog television is
possible. To achieve a high resolution, fast-moving
images require a higher bitrate than slow-moving
images. DVB-T allows for this. To improve quality,
the stations can shift the bitrates between
individual programmes in a bouquet so that action
or sports scenes can be shown in high resolution.
Although DVB-T is intended for broadcasting TV
programmes, radio programmes can also be
broadcast via DVB-T.
GSM 900 digital
FM (VHF)VHF (channels 5 - 12)
DAB band III
Central locking
UHF (channels 21 - 69)
radiotelephone
network
The VHF (very high frequency = 174 MHz to 230 MHz) and UHF(ultra high frequency = 470 MHz to 862 MHz)
channelsknown from analog radio are used for transmission. For this reason, apart from the aerials already
being used by the analog TV tuner, no additional aerials are required in the vehicle.
24
366_038
366_003
In addition to DVB-T, two other international standards exist: the US standard ATSC (Advanced Television
Systems Committee) and the Japanese standard ISDB (Integrated Services Digital Broadcasting). The actual
reception situation is shown on the map. The US and Japanese standards are not supported by TV hybrid
tuners.
DVB-T information on the Internet
The Internet provides a lot more information on the topic of DVB-T. Detailed information on Digital Video
Broadcast in the various countries can be found at www.dvb.org.
www.dvb.org
25
TV hybrid tuner (analog and DVB-T)
TV hybrid tuner
The word "hybrid" is of Latin original and means
"mixed" or "composite".
The TV hybrid tuner is, therefore, a television
receiver suitable both for analog and digital
television reception. The tuner is equipped with
three individual receivers, so tuning and diversity
are simultaneously possible. The subdivision of the
tuners into search tuners and reception tuners is
performed differently for analog and digital
reception, and will be explained in the following
section.
Order of display of programmes
Aerials 1- 4FBAS
366_002
In addition to television programmes, digital radio
programmes can be broadcast via DVB-T.
The TV hybrid tuner shows the digital television
programmes first in the station list, followed by the
analog television programmes, then the television
programmes which transmit no station name and
finally the digital radio programmes. Each display
block is sorted alphabetically.
The reception of digital radio programmes can be
deactivated with the diagnostic tester.
Te le te xt
The TV hybrid tuner is teletext capable, both in
combination with analog television programmes
and with digital television programmes. The teletext
can be selected manually in the MMI menu and is
operated with the control button.
ZDF
TV
DVB TV
MemorySource
BR
ZDF
Ch. 11
Ch. 23
Aerial
DVB Audio
ManualSound
Radio station
Unnamed stationAnalog station Digital station
366_047
Electronic Program Guide (EPG)
EPG is a data service provided by digital television
programmes. Television companies use this data
service to provide information about the
programme being broadcast. EPG can also be
selected in the MMI menu.
The TV tuner displays the information on the current
programme and those which follow. If the
programme is selected with the MMI button,
the TV tuner displays, among other things, a brief
description of the programme. EPG is not available
with analog stations.
26
366_044
366_045
Station nameCurrent programme Next programme
Setup TV
Picture parameters such as brightness, contrast,
colour, picture format and TV standard can be
adjusted in the TV set-up. The TV standard set in the
MMI is always active during operation. If the MMI is
reset to factory default, the encoded TV standard
becomes the default.
Dual audio
Like many stereo televisions for home use, the TV
hybrid tuner is dual audio capable. In the case of a
programmes broadcast in dual audio, a different
language is broadcast on each audio channel. The
programmes can only be broadcast in mono. Audio
channel A or B can be set in the MMI.
The broadcasting company decides whether
programmes are to be broadcast in dual audio.
This information is often provided in television
programme guides.
TV set-up
Settings
Brightness
Contrast
Colour
Tim
Audio channel
TV standard
Channel A
Europe
DisplaySound
366_048
TV set-up
Settings
Brightness
Contrast
Colour
Tim
Audio channel
TV standard
Europe
Channel A
Channel B
DisplaySound
366_051
Station tracking
The station tracking function makes it possible to
toggle automatically between a digital station and
the same analog station with the result that the
television station is received via an analog channel
when the vehicle leaves the digital coverage area.
The prerequisite for this is that both stations use the
same programme name.
If a station broadcasts the same programme to
various locations with different station names,
station tracking is not always guaranteed.
When driving in a border region between digital and
analog television, unnecessary switching back and
forth between stations by the tuner can be avoided
by deactivating the station tracking function.
The tuner will now stay tuned to the selected digital
or analog programme.
TV set-up
Settings
Picture format
Station tracking
Tel e t ext Zo o m
ON
OFF
Clear memory
DisplaySound
366_052
27
TV hybrid tuner (analog and DVB-T)
Installation location
The TV hybrid tuner is installed in the same position
as the previous analog TV tuner. In the Audi A8 and
A6, this is in the luggage compartment at the rear
left. In the Audi Q7, the TV tuner is installed in the
luggage compartment at the rear right
(see SSP 361). The illustration shows the installation
location in the A8.
366_014
Function diagram
30
MOST
R78
J523
31
Optical fibre break
Audio L
External input 1External input 2External output
R24
Audio R
Video
Earth
Earth
Audio L
Audio R
Video
Earth
Earth
Audio L
Audio R
Video
Earth
Earth
366_009
Legend
J523 Front information control unit
R24Aerial amplifier
R78TV tuner
The TV tuner receives its power supply via terminals 30 and 31. As a control unit integrated in the MOST
optical fibre circuit, it has an optical MOST terminal, as well as a line for optical fibre break diagnostics of the
MOST control units.
28
Two inputs are available for audio and video signals
(e.g. Rear Seat Entertainment, mobile devices such
as CD player, DVD player or the like), as well as one
output for audio and video signals. Mobile end user
devices can be connected to the TV tuner by a
pre-terminated adaptor cable, available from the
spare parts catalogue.
366_046
The inputs can be selected in MMI under CD/TV
-> Source function key. For safety reasons, the video
signal is deactivated in the front information control
unit J523 while driving. The audio channel remains
active while driving so that the inputs, e.g. for MP3
player or the like, can be used. External devices
cannot be controlled via the MMI.
Integration into the MOST bus
The TV hybrid tuner is optionally available with all
MMI systems with colour screen. As with all other
infotainment control units, TV hybrid tuner R78 is
integrated in the MOST data bus. The tuner is
currently available in one MOST variant only.
A variant for other vehicles is currently under
preparation. This tuner can be connected to devices
with a colour screen by means of the 54-pin
connector.
External AV source 1Memory
Source
CD
TV
External AV source 1
External AV source 2
ManualSound
366_053
Navigation
system J401
Digital radio
R147
TV tuner
R78
366_028
29
TV hybrid tuner (analog and DVB-T)
Function during reception of a digital station
Aerial 1
Aerial 2
Aerial 3
Aerial 4
Digital signal processing
Tun er 1
Mixer
Tun er 2
Tun er 3
Tuning
Aerial selector switchMMI station selection
Audio-visual signal
Video signal
digital
analog
Audio signal
MMI station list
FBAS
MOST
366_039
The TV hybrid tuner has three independent internal
receivers. Tuner 1 receives the signal with aerial 1.
Tuner 2 receives the signal with aerial 2. Both bits of
digital video information are added in the mixer.
Tuner 3 receives the signal from aerial 3 or aerial 4.
In search mode, the station list is updated with
tuner 3 and aerials 3 and 4. In reception mode, the
audio-visual information from the adjusted station
is added to the signal from tuners 1 and 2 in the
mixer with tuner 3.
The audio information from the composite signal of
all tuners is then relayed to the MOST bus, while the
video information is converted to an analog FBAS
signal (see SSP 293). The analog video signal is,
as with previous TV tuners, transmitted along a
coaxial cable to the front information control unit
J523.
30
If only one tuner were to be used for audio and
video reception, the reception quality would be
relatively poor, because all aerials in the vehicle
have a directional characteristic. Reception is good
if the aerial is perfectly aligned. In the case of home
aerial systems, this effect is used by rotating the
aerial towards the station. This is not possible in
vehicles.
If the vehicle is travelling in a circle, reception will
vary depending on the directional effect of the
individual aerials. While driving, therefore, the
different aerials receive the signals of varying
strength from the set stations. For digital operation,
this means that loss of signal can occur if reception
is bad. In practise, each aerial and tuner show loss
of signal at different times. The digital TV tuner
utilises this effect by adding the signals from
2-3 tuners. In case of bad reception, this means
much less loss of signal than would be the case if
only one tuner were installed. Good audio-visual
signal quality is maintained even though quality of
reception has dropped.
Aerial 3Aerial 4
Channel
Tuner 3 receives the signal from aerial 3 or aerial 4.
The signal is used temporarily for tuning purposes.
During this time, only tuners 1 and 2 are used for
picture evaluation purposes. The auto tuning
automatically updates the station list. The tuner
uses one aerial to search all channels for receivable
stations. After this, it switches over automatically to
the other aerial, and again searches all channels for
receivable stations. This process is then repeated.
Continuous tuning is not necessary, because the
station list only requires updating at relatively long
time intervals. If no tuning is needed, tuner 3 is also
used for audio and video reception.
366_050
366_042
In TV tuner R78, the changeover between aerial
3 and aerial 4 can be deactivated by encoding. If the
changeover is deactivated by encoding, the switch
stays continuously set to aerial 3. This function is
available for vehicles with 3 receiver aerials, but is
currently not in use.
31
TV hybrid tuner (analog and DVB-T)
Function during reception of an analog station
Aerial 2
Aerial 1
Aerial 3
Aerial 4
Tun er 2
Tun er 1
Tun er 3
Aerial selector switchMMI station selection
analog
digital
analog
digital
analog
digital
Digital signal processing
Selector
switch
Tuning
Mixer
Video signal
digital
analog
Audio signal
MMI station list
FBAS
MOST
366_040
Unlike the reception of digital stations, a different concept is used during reception of analog stations in order
to ensure optimal analog audio and video signal quality.
Because analog stations are received, the signals from the tuners must be converted with analog-to-digital
converters prior to digital signal processing.
If an analog station is selected in the MMI, only one tuner is in search mode at any one time. This is either
tuner 1 or tuner 3. The changeover is performed electronically in the digital signal processing unit.
Tuner 2 and the tuner which is currently not in search mode are used for audio and video reception of the
selected television channel.
Future function: multi-standard tuning
In future, auto tuning will be possible across various TV standards. In normal operation, auto tuning is
performed only in the television standard configured in the set-up.
In a multi-standard tuning system, the television programme is saved in the station memory together with the
associated television standard. The tuning routine takes into consideration the television standard stored in
the set-up, as well as the television standards of all stations stored in the station memory. This may extend the
search time accordingly.
If, for example, stations from Italy, France and Switzerland have been stored, the tuning routine runs through
all 3 television standards.
This function is not included in the original TV tuner.
32
Non-supported digital television functions
Encrypted stations which require a decoder or a smartcard for reception cannot be received by the
TV hybrid tuner.
The Multimedia Home Platform Standard, MHP for short, specifies the transmission and representation of
interactive content in digital television. The MHP standard provides not only broadcast information such as
information pages, games, programme list, extensive EPGs, but also interactive services which require an
additional back channel, such as polls, quiz questions and the like. MHP is not supported by the TV hybrid
tuner.
The standards for high-resolution television (HDTV) and for television on handhelds (DVB-H) are not supported
either.
Aerials
Aerial 4Aerial 3Aerial 2Aerial 1
The TV hybrid tuner uses the same aerial system as the previous analog TV tuner.
As the TV hybrid tuner connects the cable shield of the aerial cable to its enclosure ground via capacitors,
the aerial amplifier can no longer use the cable shield as a ground line.
The aerial amplifier requires only the ground line directly connected to the aerial amplifier for operation.
366_032
Diagnosis
If the TV picture in the MMI is selected, various
measuring and coding values are displayed directly
during diagnosis of the TV tuner with the diagnostic
tester on the MMI screen. This provides a quick
overview of, for example, the function of the aerials,
the supply voltage and the like. All of these values
can also be read out with the diagnostic tester using
the "Read data block" or "Coding" function. It is not
possible to display the values on the MMI screen
without selecting the address word 57 TV tuner with
a diagnostic tester connected.
366_049
33
TV hybrid tuner (analog and DVB-T)
Coding
Various types of vehicle can be encoded. The coding adapts the TV tuner to the respective aerial system,
as well as the fan control in the TV tuner. In the default coding, the TV tuner switches to energy-saving mode if
a source other than the TV tuner is selected in the MMI. To supply the rear seat entertainment system with
signals via the external output even when a different audio source is selected in the MMI, TV tuner R78 must
also be re-encoded. Only then is audio and video output (e.g. via headphones) possible at the rear seat
entertainment system, even though the driver is listening to a CD, for instance.
The encodable TV standards have, compared to the analog TV tuner, been supplemented to include Russia
and various Asian TV standards, with the result that 26 different TV standards can now be encoded.
List of receivable television standards
CountryTelevision standard
Central EuropePAL B / G
ItalyPAL B/G
United Kingdom, IrelandPAL I
Eastern Europe - SECAMSECAM D/K
FranceSECAM L
North AmericaNTSC M
AustraliaPAL B/H
BrazilPAL M
ArgentinaPAL N
New ZealandPAL B
Eastern Europe PALPAL D/K
PR CHINAPAL D /K
Africa PALPAL I
Greece, Egypt SECAM B/G
Africa SECAMSECAM K1
JapanNTSC M
MoroccoMOROCCO
Eastern Europe OIRT PAL PAL B/ G
Eastern Europe PALPAL B/G
Asia PALPAL B /G
South AmericaNTSC
Asia NTSC NTSC M
RussiaSECAM D/K
IndiaPAL B/G
China / Hong KongPAL I
34
366_063
Self-Study Programmes
SSP 286 New Data Bus Systems (MOST)
– LIN bus - the single-wire data bus
– MOST bus - the optical data bus
–Bluetooth
–Diagnostics bus
Order number: 000.2811.06.20
TM
- the wireless data bus
SSP 293 Audi A8 ´03 Infotainment
– Infotainment
–Sound System
–Radio Module
–Navigation
– Telephone/telematics