SIST EN 50248:2003
(Main)Characteristics of DAB receivers
Characteristics of DAB receivers
This standard describes the DAB (Digital Audio Broadcasting) receiver characteristics for consumer equipment intended for terrestrial and cable reception operating in band III and
L- band and for satellite reception in L-band. Dedicated receivers for specific applications are not within the scope of this standard.
Eigenschaften von DAB-Empfängern
Caractéristiques du récepteur DAB
Characteristics of DAB receivers
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN 50248:2003
01-oktober-2003
1DGRPHãþD
SIST EN 50248:1999
Characteristics of DAB receivers
Characteristics of DAB receivers
Eigenschaften von DAB-Empfängern
Caractéristiques du récepteur DAB
Ta slovenski standard je istoveten z: EN 50248:2001
ICS:
33.160.20 Radijski sprejemniki Radio receivers
SIST EN 50248:2003 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN 50248:2003
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SIST EN 50248:2003
EUROPEAN STANDARD EN 50248
NORME EUROPÉENNE
EUROPÄISCHE NORM August 2001
ICS 33.160.20 Supersedes EN 50248:1997
English version
Characteristics of DAB receivers
Caractéristiques du récepteur DAB Eigenschaften von DAB-Empfängern
This European Standard was approved by CENELEC on 2000-08-01. CENELEC members are bound to
comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the Central Secretariat or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any
other language made by translation under the responsibility of a CENELEC member into its own
language and notified to the Central Secretariat has the same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Czech Republic,
Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway,
Portugal, Spain, Sweden, Switzerland and United Kingdom.
CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Central Secretariat: rue de Stassart 35, B - 1050 Brussels
© 2001 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 50248:2001 E
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EN 50248:2001 - 2 -
Foreword
This European Standard was prepared by the Technical Committee CENELEC TC 206, Consumer
equipment for entertainment and information and related sub-systems.
The text of the draft was submitted to the Unique Acceptance Procedure and was approved by
CENELEC as EN 50248 on 2000-08-01.
This European Standard supersedes EN 50248:1997.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2002-02-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2003-08-01
Annexes designated "normative" are part of the body of the standard. Annexes designated "informative"
are given for information only. In this standard annexes A and C are informative and annex B is
normative.
__________
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Contents
1 Scope.4
2 Normative references .4
3 Terms and definitions .5
4 Basic implementation and functional performance requirements .5
4.1 Audio decoder .5
4.2 Automatic mode selection.7
4.3 Frequency bands .7
4.4 Service selection .7
4.5 Receiver reactions to a multiplex re-configuration.8
4.6 Automatic switching to another ensemble .8
4.7 Response to conditional access (CA) services .8
4.8 Output for audio and other services.8
4.9 Transparency for copy protection .9
4.10 Coding profiles (Minimum implementation of specified coding profiles).9
5 Interfaces .9
5.1 General.9
5.2 RF input .9
5.3 Analogue audio interface [EN 61938] .9
5.4 Digital audio interface [IEC 60958-3].9
5.5 Coded audio interface [IEC 61937].9
5.6 General digital interface (F in Figure 1) .10
5.7 Conditional access interface .10
6 Options.10
6.1 General.10
6.2 Receiver display .10
6.3 Other features .10
7 Minimum performance levels and measuring methods .11
7.1 General conditions.11
7.2 Audio part - Performance requirements .11
7.3 R.F. part .12
Annex A (informative) Recommended centre frequencies for DAB .18
Annex B (normative) Characteristics of a Rayleigh channel.21
Annex C (informative) Bibliography .26
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1 Scope
This standard describes the DAB (Digital Audio Broadcasting) receiver characteristics for consumer
equipment intended for terrestrial and cable reception operating in band III and
L- band and for satellite reception in L-band. Dedicated receivers for specific applications are not within
the scope of this standard.
2 Normative references
This European Standard incorporates by dated or undated reference, provisions from other publications.
These normative references are cited at the appropriate places in the text and the publications are listed
hereafter. For dated references, subsequent amendments to or revisions of any of these publications
apply to this European Standard only when incorporated in it by amendment or revision. For undated
references the latest edition of the publication referred to applies (including amendments).
EN 50255, Digital Audio Broadcasting system – Specification of the receiver data interface (RDI)
1)
EN 55013 , Limits and methods of measurement of radio disturbance characteristics of broadcast
receivers and associated equipment (CISPR 13, mod)
1)
EN 55020 , Electromagnetic immunity of broadcast receivers and associated equipment - Limits and
methods of measurement of immunity characteristics of sound and television broadcast receivers and
associated equipment
EN 60169-24, Radio-frequency connectors - Part 24: Radio-frequency coaxial connectors with screw
coupling, typically for use in 75 ohm cable distribution systems (Type F)
EN 60315-4, Methods of measurement on radio receivers for various classes of emission - Part 4:
Receivers for frequency-modulated sound broadcasting emissions
EN 61606, Audio and audiovisual equipment – Digital audio parts - Basic methods of measurement of
audio characteristics (IEC 61606)
EN 61938, Audio, Video and audiovisual systems – Interconnection and matching values. Preferred
matching values of analogue signals (IEC 61938)
EN 300 401, Digital Audio Broadcasting to mobile, portable and fixed receivers. (DAB system standard).
IEC 60169-10, Radio-frequency connectors - Part 10: R.F. coaxial connectors with inner diameter of
outer conductor 3 mm (0,12 in) with snap-on coupling - Characteristic impedance 50 ohms (Type SMB)
IEC 60315-1, Methods of measurement on radio receivers for various classes of emission - Part 1:
General considerations and methods of measurement, including audio-frequency measurement
(harmonized as HD 560.1)
IEC 60958-3, Digital audio interface - Part 3 : Consumer applications
IEC 61937, Interface for non-linear PCM encoded audio bitstreams applying to IEC 60958
ISO/IEC 11172-3, Coding of moving pictures and associated audio for digital storage media at up to
1,5 Mbit/s - Part 3: Audio
1)
An amendment concerning digital receivers is in preparation.
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ISO/IEC 11172-4, Coding of moving pictures and associated audio for digital storage media at up to
1,5 Mbit/s - Part 4: Compliance testing
ISO/IEC 13818-3, Generic coding of moving pictures and associated audio information - Part 3: Audio
ISO/IEC 13818-4, Generic coding of moving pictures and associated audio information - Part 4:
Compliance testing
ETSI TR 101 496-2, Digital Audio Broadcasting system (DAB) - Guidelines and rules of implementation
and operation. Volume 2: System feature.
ETSI TS 101 757, Digital Audio Broadcasting system (DAB) - Conformance Testing for DAB Audio
3 Terms and definitions
For the purpose of this European Standard, the following definitions apply.
Other definitions, abbreviations and symbols are solely related to DAB unless stated otherwise.
3.1
DAB receiver
receiver which is intended to receive and decode programmes transmitted according to the DAB system
specification EN 300 401
NOTE Figure 1 shows an example of a functional block diagram of a DAB Receiver according to EN 300 401(for information only).
3.2
minimum requirement
is the lowest value that a DAB receiver should fulfil in order to be called a DAB receiver. It takes into
account low cost receivers
4 Basic implementation and functional performance requirements
4.1 Audio decoder
The audio decoder function of a DAB receiver shall conform to the subset of ISO/IEC 11172-3 as defined
in EN 300 401. The conformity is described in ETSI TS 101 757. The audio decoder should include an
error concealment method which may be based on the ScF-CRC (Scale Factor-Cyclic Redundancy
Check) as defined within EN 300 401. If for any reason the data stream cannot be decoded, the receiver
shall mute.
The audio part shall be able to decode DAB bit streams corresponding to both 24 and 48 kHz sampling
frequencies.
It shall comply with ISO/IEC 11172-3 and ISO/IEC 13818-3 (bit-rates above 256 kHz/s are optional).
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D
C
PAD
L-Band t errestrial
I
A L-Band satellite
L
5
23 4
Band III
1
RF Input
R
FFT, Demux &
J
Audio Decoder
IF- A/D
RF Front End Audio Processing
Channel Decoder
Speakers
System Bus
Analog/Digital
H
System Control
10
FIC &TII Decoding
Conditional 8 9
7
6
Access
Other Signal Sources
Man Machine Packet Mode
Synchronization
Interface (MMI) Decoder
Timing (FM, Cassette,CD, DCC)
G
Card
Display Digital Record / Play
Reader
Coded Audio
F DATA out E
Block 8 and 10 are optional, block 9 is not part of the DAB receiver
Figure 1 - Example of a functional block diagram of a DAB receiver
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4.2 Automatic mode selection
4.2.1 Introduction
Four different transmission modes are defined: modes I, II, III & IV. Radio frequency characteristics are
described in EN 300 401(see clause 15, Radio frequency characteristics).
The modes can be detected by checking the following relevant parameters of the DAB signal: the frame
duration, null symbol duration and carrier spacing.
4.2.2 Requirements
The receiver shall detect the mode of the DAB signal and switch to the appropriate reception mode.
4.3 Frequency bands
The receiver shall provide reception of at least one DAB ensemble, in the following RF Bands:
Band III: 174 MHz to 240 MHz
L-Band: 1 452 MHz to 1 492 MHz (see note 1)
Other bands: see note 2
The centre frequencies are given in annex A. The receiver should be able to correct transmitter
frequency offsets by up to ± 1/2 of the carrier spacing.
NOTE 1 L-Band as defined by ITU WARC-92. L-Band is allocated for both terrestrial and satellite digital sound broadcasting. See
also "Radio Regulations, Article 8 (Frequency Allocations) International Telecommunication Union. Update in 1995 Geneva Switzerland".
NOTE 2 For specific demands (e.g. cable distribution etc.) other frequencies can optionally be used.
4.4 Service selection
4.4.1 Introduction
The MSC (Main Service Channel) and the FIC (Fast Information Channel) carry the components and
Multiplex Configuration Information (MCI) respectively of the services which make up a DAB Ensemble
mulltiplex.
Each service has one or more service components. Several services may be carried in one Ensemble
multiplex.
A user of a DAB receiver accesses service components by selecting a service.
A distinction is made between the essential service component of a service, which is called the "Primary"
component and other components which are considered "Secondary".
The MCI is carried in the FIC to avoid the inherent transmission delay associated with the time-
interleaving process applied to the MSC.
4.4.2 Requirements
To gain access to the desired programme service, the receiver must decode the MCI, make the
information available to the MMI (Man Machine Interface) for selection, and then output the selected
service.
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4.5 Receiver reactions to a multiplex re-configuration
Information on a multiplex reconfiguration is provided in advance, to the receiver. This information
includes the following parts:
− the level of a forthcoming multiplex reconfiguration.
− the time when the receiver has to switch according to the MCI (Multiplex Configuration
Information).
− next MCI.
The receiver shall follow the multiplex reconfiguration as described in ETSI TR 101 496-2.
In cases where the service is unchanged by the reconfiguration, reception of that service should continue
without any adverse effect.
4.6 Automatic switching to another ensemble
In order to allow service following of a particular DAB service the ability of a mobile DAB receiver to
switch automatically to another ensemble is mandatory. Service following should be as described in
ETSI TR 101 496-2.
4.7 Response to conditional access (CA) services
4.7.1 Introduction
In DAB some service components belonging to a service may be individually scrambled to make these
components incomprehensible for unauthorised users.
4.7.2 Requirements for DAB receivers without CA capabilities
These receivers shall either make scrambled service components unavailable for selection or indicate
their presence together with the fact that they are scrambled and thus not accessible.
Special care has to be taken in the transition from "unscrambled" to "scrambled". When this occurs on
one of the selected service components, the receiver shall mute the audio and give an appropriate
indication.
NOTE CA capabilities are optional (see clause 6.)
4.8 Output for audio and other services
4.8.1 Introduction
The DAB system provides both programme and data services.
Programme services comprise of an audio primary service component and (optionally) additional
secondary service components. Each audio service component can also contain PAD (Programme
Associated Data) which is used to convey information intimately linked to the sound programme in terms
of content and synchronisation. DRC (Dynamic Range Control) is an example of a PAD application.
Data services comprise of non-audio primary service components and may optionally have additional
secondary service components.
4.8.2 Requirements
The DAB receiver shall output the audio signal to e.g. loudspeakers and/or provide other outputs via one
of the interfaces specified in clause 5.
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4.9 Transparency for copy protection
The DAB system allows transmission of copy protection information within the header of the ISO/IEC-
coded audio bit stream. The information shall be transferred, together with the complete header, to the
digital audio output as described in 5.4, 5.5 or 5.6.
4.10 Coding profiles (Minimum implementation of specified coding profiles)
The channel decoder shall support all protection profiles and shall be able to decode at least one stereo
audio programme with a bit rate of up to 256 kbit/s.
5 Interfaces
5.1 General
If any of the following interfaces are applied, the described standardised versions should be used.
Dedicated solutions, which do not require connections to other standard products, may use special
interfaces.
5.2 RF input
(A in Figure 1)
Domestic DAB receiver: 75 Ohms (female) acc. to EN 60169-24 (type "F")
Car DAB receiver: 50 Ohms (male) acc. to IEC 60169-10 (type "SMB")
Portable DAB receiver: 75 Ohms (female) acc. to EN 60169-24 (type "F")
Antenna interface specifications for receivers designed to support an active antenna:
Frequency range Band III and L-Band
Antenna connector IEC 60169-10 (SMB, male 50 Ohms)
Remote power supply 8,8 V – 16 V
Maximum current < 100 mA
Maximum input power at receiver Band III: -10 dB(mW) + Gain
L-Band: -25 dB(mW) + Gain
Typical values for the active antenna:
Noise figure < 3 dB
Gain (without cable loss) 6 dB
Intermodulation (IM3) * 40 dBc
*Measured with a two-tone signal: Δf = 100 kHz, total power at the receiver = -25 dB(mW).
5.3 Analogue audio interface [[[[EN 61938]]]]
(I, J and H in Figure 1)
5.4 Digital audio interface [[[[IEC 60958-3]]]]
(D in Figure 1)
5.5 Coded audio interface [[[[IEC 61937]]]]
The DAB receiver may optionally provide an interface/output of the error-corrected but source-coded bit
stream of one audio sub-channel. The audio coding is based on ISO/IEC 11172-3 or ISO/IEC 13818-3.
(G in Figure 1)
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5.6 General digital interface
(F in Figure 1)
Receiver Data Interface (RDI) (EN 50255).
5.7 Conditional access interface
The conditional access interface is under consideration.
6 Options
6.1 General
The following features are not mandatory for a basic receiver, but are recommended. When any of these
optional features are supported they shall be implemented in accordance with ETSI TR 101 496-2.
6.2 Receiver display
It is recommended that 16 characters be used, and the following information be displayed:
− service label;
− service component label;
− programme type;
− language;
− ensemble label;
− dynamic label
− status for conditional access;
− region label;
− time and date;
− support character set "0000" (Complete EBU Latin based repertoire), as defined in 5.2.2.2
of EN 300 401.
6.3 Other features
− support service following from DAB to FM and vice-versa;
− mono / stereo / joint stereo;
− selective volume adjustment for music and speech;
− Dynamic Range Control (DRC);
− reaction to announcements:
− alarm,
− traffic,
− weather,
− etc.;
− switching to regional announcements using TII;
− mute in case of:
− non audio service,
− future defined service;
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− response to Pnum switching (Programme number):
− Programme Type, PTy (static or dynamic),
− PTy preview,
− PTy downloading,
− conditional access.
7 Minimum performance levels and measuring methods
7.1 General conditions
7.1.1 Introduction - Published specifications
A comprehensive specification shall contain all the performance values in accordance with this chapter.
Abbreviated specifications may be published in addition. In both cases, the published values of all the
characteristics shall be measured by the methods specified here. There should be a statement to that
effect in the text or footnotes of the measuring results. For example, this might read: "measured in
accordance with EN 50248". All measuring results shall be published for all frequency bands covered.
7.1.2 Power supply
The power supply shall be in accordance with IEC 60315-1.
7.1.3 Atmospheric conditions
The atmospheric conditions for measurement shall be within the ranges:
Ambient temperature: 15°C to 35°C
Relative humidity: 25 % to 75 %
Atmospheric pressure: 86 kPa to 106 kPa
For further information, see EN 60068-1, EN 60721 and IEC Guide 106.
7.1.4 BER measurement conditions
The bit error ratio (BER) shall be measured at the receiver's convolutional decoder output, such as "F" in
Figure 1. During the measurement, the receiver should remain synchronised. Unless otherwise noted,
BER measurements shall be performed in the MSC, using an equal error protection (EEP) sub-channel
with code rate 1/2.
Any known digital pattern with a length of more than 1 symbol can be used as test sequence. For
example, either all zeros or a test pattern confirming to CCITT Rec.0.151 would be suitable.
7.1.5 DAB signal
The generated DAB signal shall be in accordance with EN 300 401. The DAB signal power is defined as
the r.m.s. power of the DAB-ensemble.
7.2 Audio part - Performance requirements
ETSI TS 101 757 specifies the procedures for testing the conformance of the DAB audio decoder.
Audio characteristics shall be measured according to EN 61606. This standard applies to the basic
methods of measurement of the audio characteristics of the digital audio part of audio and audiovisual
equipment (for both consumer and professional uses). The standard describes tests for equipment with
analogue output and digital input.
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7.3 R.F. part
7.3.1 Sensitivity
7.3.1.1 Method of measurement (Gaussian Channel)
The measurement set up is given in Figure 2. The signal generator shall be connected to the RF-input
"A" of the receiver under test. The BER shall be measured at the output "F".
-4
The input power is reduced until the BER reaches 10 .
AFDAB BER
Signal
Receiver Meter
Generator
Power
Meter
Figure 2 - Block diagram for the measurement of the sensitivity and the max. input power
7.3.1.2 Presentation of results
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The sensitivity is the input power expressed in dB(mW) at which the BER reaches 10 .
7.3.1.3 Requirements
Minimum requirement: -81 dB(mW) (for VHF and L-band)
NOTE External antenna / cable losses and additional connector losses are not included.
7.3.2 Maximum input power
7.3.2.1 Introduction
The maximum input power is the maximum input level at which the DAB receiver will perform according
to criteria given in 7.3.2.2
7.3.2.2 Method of measurement (Gaussian Channel)
The same measurement set up as given in 7.3.1.1 shall be used. The input power is increased until the
-4
BER reaches 10 or just before synchronisation is lost.
7.3.2.3 Presentation of results
The maximum input power is expressed in dB(mW). It shall be given for all frequency bands covered.
7.3.2.4 Requirements
Minimum requirements VHF: -10 dB(mW) . -20 dB(mW),
depending on the type of receiver (see Table 1)
L-Band: -25 dB(mW)
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Table 1 - Minimum requirements for maximum input power
Minimum requirement Mobile receiver Stationary receiver Portable receiver
VHF -10 dB(mW) -15 dB(mW) -20 dB(mW)
L-Band -25 dB(mW) -25 dB(mW) -25 dB(mW)
7.3.3 Selectivity
For selectivity two kinds of measurements are considered: Adjacent channel selectivity (A ) and far-off
CS
selectivity.
7.3.3.1 Adjacent channel selectivity
7.3.3.1.1 Method of measurement
Both wanted signal and interferer shall be DAB signals according to 7.1.5. The spectrum shall be in
accordance with Figure 3.
0,77MHz
0
0,97MHz
-45
1,3MHz
-60
2,5MHz
-80
01 2 3
offset from centre frequency [MHz]
Figure 3 - Spectrum mask of the DAB signal for selectivity measurements.
The difference between the centre frequencies of the DAB ensembles shall be 1,712 MHz,
corresponding to a guard band of 176 kHz.
The measurement set up is depicted in Figure 4.
The power level of the wanted signal P at the DAB receiver input "A" in Figure 4 shall be adjusted to
wanted
-70 dB(mW) using the attenuator 1 when signal generator 2 is switched off. The signal level P of
unwanted
-4
the interfering ensemble shall then be increased until a bit error ratio (BER) of 10 at point "F" is
reached. (see 7.1.4.)
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DAB Signal Attenuator
Generator1 1
(wanted)
AF BER
DAB
Combiner
Meter
Receiver
Signal
Attenuator
Generator2
2
Selective
(unwanted)
Power
Meter
Figure 4 - Block diagram for selectivity measurements.
7.3.3.1.2 Presentation of results
The adjacent channel selectivity (A ) of a DAB receiver is expressed in dB and shall be given for VHF
CS
and L-band separately. These values shall be calculated from the adjusted signal levels by equation:
A = P [dB] -P [dB] = P [dB] + 70 [dB]
CS unwanted wanted unwanted
7.3.3.1.3 Requirements
Minimum requirement (for P ): ACS ≥ 30 dB (VHF and L-Band)
wanted = - 70 dB(mW)
7.3.3.2 Rejection of unwanted signals (far-off selectivity)
7.3.3.2.1 Introduction
An unwanted signal received together with the wanted signal at the input of the receiver may have a
degrading effect on reception quality.
7.3.3.2.2 Method of measurement
The measurement set up is shown in Figure 4.
The wanted signal is a DAB signal (according to 7.1.5.)
Adjust attenuator 1 so that the power level measured at the input "A" to the receiver becomes-
70 dB(mW).
The unwanted signal is a standard FM modulated signal as defined in EN 60315-4.
This measurement shall be carried out on the upper, lower and centre frequencies, in both VHF and L-
band. The frequency of the unwanted signal should be ≥ 5 MHz from the centre frequency of the wanted
DAB signal. The output power of the unwanted signal (measuring at the DAB receiver input "A") is
-4
increased until the BER is 10 .
7.3.3.2.3 Presentation of results
The rejection of unwanted signals is expressed in dB.
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The relative level of the maximum permissible unwanted signal is given for both measurements by the
equation:
R = P [dB] - P [dB] = P [dB] + 70 [dB]
r unwanted wanted unwanted
where
R is the rejection ratio.
r
7.3.3.2.4 Requirements
Minimum requirement: 40 dB (VHF and L-Band) for any in-band or out-of-band interfering frequency with
an offset ≥ 5 MHz from the centre of the wanted DAB signal.
7.3.4 Performance in a Rayleigh channel
7.3.4.1 Sensitivity
7.3.4.1.1 Introduction
It is recognised that the behaviour under mobile conditions is one of the strong features of the DAB
system. The objective of this measurement is to provide a reference for the performance of a DAB car
receiver in a dynamically changing environment. Typically, such an environment is described by the
Rayleigh channel model.
The effects described above, model the propagation of electromagnetic waves in realistic terrain, and
under moving conditions. Included in these models is the Doppler-effect, as well as multi-path reception
plus fast and slow fading. Since many combinations of these effects are possible, there has been effort
to standardise a set of conditions for measurement purposes. These so-called profiles were laid down in
the [COST 207] document on digital land mobile radio communications. Extracted from that document,
certain relevant profiles have been selected. These are given in annex B.
Based on static conditions, it is possible to compare the behaviour of different receivers. However, since
the channel is changing dynamically, it is difficult to test without long term observation. Therefore, long
-4
term evaluation is required, during which the BER may not drop below 10 .
7.3.4.1.2 Method of measurement
The block diagram of a basic set-up for channel simulation is shown in Figure 5.
DAB
AFDAB BER
Channel Variable
Signal
Receiver Meter
Simulator Attenuator
Generator
Selective
Controler
Power
Meter
Figure 5 - Block diagram for measuring the performance in a Rayleigh channel
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The DAB signal generator is set to one of the centre frequencies given in Table 2, and is modulated by a
DAB encoder. A channel simulator is inserted between the DAB signal generator and the variable
attenuator. This simulator must be programmed through its controller with parameters corres
...
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