Digital Audio Broadcasting – radio now and for the future · 2016-09-05 · 2 EBU Technical Review Autumn 1995 Kozamernik Digital Audio Broadcasting – radio now and for the future

2 EBU Technical Review Autumn 1995Kozamernik

Digital Audio Broadcasting– radio now and for the futureF. Kozamernik (Senior Engineer, EBU)

1. Introduction

The Eureka 147 Digital Audio Broadcasting (DAB)system is well known to readers of this journal:there is already a wealth of literature which givesinformation on the technical characteristics and theperformance of the system1.

Recently, some debate has started on the role thatDAB could play in the future information high-way. The present situation is characterized by theconvergence of computer, telecommunication andbroadcasting technologies, and the divergence ofdifferent delivery and storage media which useadvanced digital signal-processing techniques.Consumers are overwhelmed by the new electron-ic gadgets which appear almost daily on the mar-ket, and they are astonished by the radically newtechnical innovations that are being designed tochange their life-long habits. Even the broadcast-ing sector itself is facing profound changes, partic-ularly a growing competition between the publicand the private broadcasters.

1. See the bibliography given in issues 2 and 3 ofDAB Newsletter, published by the EBU in 1993.

The world’s first DAB services werelaunched in the United Kingdom andin Sweden at the end of September.

With several other broadcastersalso preparing for the “big day”, theauthor reports on the current statusof DAB technology, and summarizesthe progress being made to imple-ment DAB services worldwide.

The present article reviews the current status ofDAB worldwide, at a time when official serviceshave already started in Sweden and the UnitedKingdom, and as broadcasters elsewhere preparefor the imminent launch of their DAB services.

2. Analogue radio

In 1895, Guglielmo Marconi (1874 – 1937) con-ducted his first experiments with wireless telegra-phy on his father’s estate in Italy. Now, a centurylater, analogue AM and FM emission standardshave achieved technological and operationalmaturity; every day, radio reaches about twobillion receivers worldwide, offering the listenersa large diversity of speech and music pro-grammes.

Nevertheless, these analogue emission standardsare failing to provide many listeners with the audioquality they have come to expect in this age of thecompact disc.

Original language: EnglishManuscript received 25/9/95.

The DAB logo has beenregistered by a member of theEureka 147 DAB consortium.

3EBU Technical Review Autumn 1995Kozamernik

2.1. Frequency shortages

The frequency bands available for sound broad-casting are either rapidly saturating or havealready become saturated. As a result, the recep-tion quality is suffering more and more frommutual interference between transmissions. Inmany countries, there are now very little or noprospects of additional radio services beingprovided by means of the existing analoguetechnologies.

2.2. Difficulties with FM radioreception

FM radio services in VHF Band II were originallyplanned in the 1950s and 60s for fixed receptionusing a directional receiving antenna at a heightof 10 m above ground level. Those listeners whohave installed a good outdoor (or loft-mounted)antenna are generally quite happy with the qualityof their FM reception. However, the majority ofradio listening today is carried out with portableand mobile receivers which use only a simplewhip (or telescopic) antenna, resulting in sub-standard FM reception quality in many areas.

FM reception quality on a portable radio can bevery variable inside large buildings such as multi-storey “tower blocks”. This is due to the atten-uation of the FM radio signals by (and internalreflections from) the walls of the building(particularly if constructed from steel-reinforcedconcrete).

When listening on a portable or a mobile receiver,FM reception can be badly affected by shadowing(i.e. the blocking or screening of the signals by tallbuildings and hills which lie in the direction of thetransmitter) and by passive echoes (the arrival atthe receiver of delayed “multipath” signals whichhave been reflected from tall buildings and hills).For the motorist, there is the additional problemthat the strength and quality of the received FMsignals can change very rapidly as the vehicleproceeds. This places an almost impossibleburden on the car radio receiver.

2.3. Shortcomings of internationalbroadcasting

International broadcasters use terrestrial AM sys-tems on the shortwave (HF) bands as the primarymeans of delivering radio to wide supranationalareas. These transmissions are affected by diurnaland seasonal propagation variations which causefading and occasional loss of signal completely.

Hence, as a consumer commodity in the age of theCD, international shortwave broadcasting has lostmuch of its former attraction.

Today, one of the main objectives of internationalbroadcasters is to design and implement viableservices which are based on a new universal digitaldelivery system. This could be either a satellite ora terrestrial system, possibly a combination of thetwo, which in time would replace shortwavebroadcasting (see Section 15.).

3. Beginnings of digital radio

Radio is witnessing an increasingly strong com-petition from non-broadcast media which usedigital techniques to produce the optimum perfor-mance, at a cost that is acceptable to large con-sumer markets.

The compact disc was the first mass-storage digitalmedium to offer superior sound quality in thedomestic marketplace. The CD has now beenjoined by various other tape and disk storage for-mats, such as R-DAT and S-DAT, digital compactcassette (DCC), MiniDisc (MD) and CD-I.

In parallel with these mass-storage developments,digital sound-broadcasting systems – which userelatively simple source- and channel-codingtechniques – have been developed. These systemshave been designed for specific purposes whereimmunity to frequency-selective fading is notrequired and where reception is only via a staticreceiver. They do not provide reliable reception ina multipath propagation environment.

The main systems to date are now describedbriefly.

3.1. NICAM 728

NICAM 728 is a digital stereophonic soundsystem which was developed for use with PALterrestrial television broadcasting (recently for usewith SECAM also). Directional receiving anten-nas are used to eliminate, or at least reduce, anymultipath problems.

3.2. DSR

The Digital Satellite Radio (DSR) system is a high-quality stereo satellite system which providessixteen sound programmes in an FSS/BSS satellitechannel.

3.3. ADR

The Astra Digital Radio (ADR) system has beendeveloped recently for the satellite distribution of


digital sound signals to fixed individual receiversand to feed national FM networks (and possiblyDAB networks at a later date). It is planned thatADR services will commence later this year.

The ADR system makes use of unused capacityavailable on the existing analogue transponders ofAstra satellites. Each transponder can accommo-date twelve digitally-modulated subcarriers, eachof which can carry a digital stereo sound pro-gramme at a data rate of 192 kbit/s.

3.4. DVB

Recently, the European Digital Video Broadcast-ing (DVB) Project has developed and standardizeda digital television broadcasting system for satel-lite and cable delivery [1], [2], [3]. The DVB sys-tem makes use of ISO/IEC MPEG-2 video/audiosource coding and transport packet multiplexing,in conjunction with either QPSK modulation (forsatellite delivery) or multi-level QAM modulation(for cable delivery).

The DVB system allows potentially large numbers(several hundreds) of audio programmes to becarried in a BSS/FSS satellite channel, but it isonly suitable for stationary reception at home.

4. Eureka 147 DAB system

The Eureka 147 DAB system has been developedby a European consortium which was establishedin 1987 and now has over 40 members; it is com-posed of manufacturers, broadcasters, networkproviders and research institutes. The ProjectOffice of the Eureka 147 Consortium is managedby the DLR2, based in Cologne, Germany. AEureka on-line information service is available onthe Internet World Wide Web and can be accessedvia: http://www.dlr.de/DAB/.

The Eureka 147 DAB system has been designed toprovide high-quality, multi-programme digitalsound and data broadcasting services – not only forreception by fixed receivers but particularly forin-car and portable reception using a simple whipantenna.

The Eureka DAB system can operate in any dedi-cated broadcasting band at both VHF and UHF.Even when working in severe multipath condi-tions, such as in dense urban areas, the systemprovides an unimpaired sound quality in the DABreceiver. The system has also been designed as a

2. Deutsche Forschungsanstalt für Luft- und Raumfahrt e.V.

flexible, general-purpose, integrated servicesdigital broadcasting system which supports a widerange of source- and channel-coding options, aswell as programme-associated and independentdata services.

4.1. DAB ensembles

Unlike conventional analogue broadcasting, theDAB system enables several sound programmesto be multiplexed together and broadcast on thesame radio-frequency channel. The number ofprogrammes in an “ensemble” (i.e. a multiplex)depends on the trade-off implemented between:

1) the encoded bit rate per audio programme;

2) the channel protection that is provided againsterrors occurring on the propagation path;

3) the data capacity required for the variousprogramme-associated and independent dataservices that are included in the ensemble.

4.2. COFDM

In the Eureka 147 system, a transmission tech-nique called coded orthogonal frequency divisionmultiplex (COFDM) is employed. In this system,the complete ensemble is transmitted via severalhundred (or even several thousand) closely-spaced RF carriers which occupy a total bandwidthof around 1.5 MHz, the so-called frequency block.Each individual RF carrier transmits – at a fairlylow data rate – only a tiny fraction of the total datawhich makes up the ensemble, thus providing aform of diversity reception.

With COFDM, multipath reception is practicallyeliminated. Due to the low data rate of each RFcarrier, any delayed reflections of the signal (i.e.“passive echoes”) add in a constructive manner tothe direct signal already received. The only situa-tion where passive echoes do not contribute in aconstructive manner is when the delays are muchgreater than the time guard interval of the DABsignal, i.e. greater than 300 �s at VHF. (Delays ofthis magnitude are extremely rare in most types ofterrain where multipath reflections are apparent.)

4.3. A conceptual DAB transmitterand receiver

Figure 1 (top) shows a conceptual DAB transmit-ter drive, in which a sound and a data service arecoded individually at source level, then errorprotected and time interleaved. Next, the soundand data services are multiplexed into the MainService Channel, together with other services,according to a predetermined but changeableservice configuration. The multiplexer output is


frequency interleaved and combined with multi-plex control and service information which travelin a Fast Information Channel which is not timeinterleaved. At this stage, very rugged synchro-nization pulses are added and then OFDM isapplied to the signal before, finally, it is DQPSK-modulated onto a large number of RF carriers toform the complete DAB signal.

Figure 1 (bottom) shows a conceptual receiver inwhich the wanted DAB ensemble is selected in theanalogue tuner, downconverted and quadraturedemodulated before applying it to an analogue-to-digital converter. Thereafter, the receiver per-forms the operations of the transmitter in reverseorder. The digitized output of the converter is fedto the Fast Fourier Transform (FFT) stage and thendifferentially demodulated. This stage is followedby a time and frequency de-interleaving process,and error correction. Next, the original coded ser-vices are further processed in an audio decoder,including an error concealment circuit, to producethe left and right audio signals.

The decoding of more than one service componentfrom the same ensemble, such as an audio pro-gramme in parallel with a data service, is practica-ble and provides interesting possibilities for newreceiver features.

5. Eureka 147 and IntellectualProperty Rights

Recently, the Eureka 147 Consortium has resolvedthe issues concerning DAB and Intellectual Prop-erty Rights (IPR). The DAB system is now consid-ered as fully open; it can be manufactured by anyinterested party following the fulfilment of thelicence conditions. The Consortium is willing tonegotiate licences with other parties on a non-discriminatory basis and on reasonable terms andconditions.

No broadcaster will be charged for implementingDAB networks based on the Eureka 147 system.

Frequencyinterleaver OFDM

Syncgenerator

Soundservice

Dataservice

Servicesconfiguration

Audioencoder

Channelencoder

Timeinterleaver

Timeinterleaver

Channelencoder

Dataencoder

DABsignal

Other sound services

Other data services

MUX

DAB transmitter drive

Tuner,down-converterand quadrature

demodulator

A/Dconversion

FFT anddifferential

demodulator

Time & frequencyde-interleaving

and error -correction

Userinterface

Datadecoder

Audiodecoder

L

R

Dataservices

DAB receiver

FICgenerator

Control andsynchronization

MUXcontroller

Figure 1Conceptual DAB

transmitter drive (top)and DAB receiver.


6. Principal advantages ofDAB

6.1. CD quality

DAB has several advantages over conventionalanalogue AM/FM broadcasting. The main benefitis that the high sound quality, normally indistin-guishable from that of the CD, is effectively freefrom interference. However, DAB also has aunique ability to serve the mobile audience, thusproviding high-quality coverage wherever andwhenever required.

6.2. Spectrum efficiency

A further advantage of DAB is that it is spectrum-efficient. This means that it will be possible toincrease the number of radio stations – initially bya factor of at least three when compared with FM– without congesting the radio waves. As moreefficient audio coding (compression) methods areintroduced, it will be possible to carry even moreradio programmes with no degradation to existingservices, and without needing to modify existingreceivers. A radio set of the future will thus makeit possible to choose, for example, a favourite typeof music station from among hundreds of musicstations.

6.3. “Active echoes”

As mentioned in Section 4.2., the Eureka 147 DABsystem is able to use “passive echoes” such thatthey add in a constructive manner to the directsignals already received. The Eureka system isalso able to use “active echoes” constructively –i.e. delayed signals generated by other co-channeltransmitters. This leads to two important concepts:

– single frequency networks (SFNs);

– co-channel gap-fillers.

The SFN concept enables all transmitters coveringa particular area with the same set of sound pro-grammes to operate on the same nominal radio-frequency channel, i.e. within the same frequencyblock. All SFN transmitters need to be synchro-nized, in terms of both frequency and time, and thetransmitted bit stream must be identical. Althoughthe signals emitted by the various transmitters arereceived with different time delays, the receiverrecognises this as a direct signal coming from thenearest transmitter, followed by “active echoes”coming from other transmitters in the SFN.

Gap-filling represents the second type of applica-tion which makes full use of the “active echo”

concept. A gap-filler acts rather like a mirror; itreceives the signals from the main transmitter andretransmits them at low power on the samefrequencies to provide coverage in an area wherethe main transmitter is not received satisfactorily.Although the listener receives signals from boththe main transmitter and the gap-filler at slightlydifferent times, the two sets of signals add togetherconstructively to enhance the reception of theprogramme. The gap-filling concept is useful bothfor terrestrial and satellite broadcasting systems.

As a result of these two concepts, DAB eliminatesthe problem of having to retune car radios atfrequent intervals. At present, long-distancedrivers who are listening to an FM programme areforced to retune as they move away from the areacovered by one transmitter to that of another.With DAB, however, a car radio does not need tobe retuned because the wanted station will be inthe same frequency block everywhere within anational or regional service area.

6.4. Flexible bit rates

The Eureka 147 DAB system is a highly flexibleand dynamically reconfigurable system. It canaccommodate a range of bit rates between 8 and384 kbit/s3, with a range of channel protectionmechanisms.

Some broadcasters are interested in using lowaudio bit rates per audio channel, say between 16and 64 kbit/s, in order to transmit more channels atslighly reduced quality. With a bit rate of 32 kbit/sper audio channel, the Eureka multiplex of1.5 MHz can accommodate as many as thirty-sixchannels, with 1/2 channel protection level.

6.5. DAB transmission modes

Technically, the Euraka 147 DAB system can beused at any frequency between 30 MHz and3 GHz. This wide range of frequencies includesVHF Bands I, II and III, UHF Bands IV and V, andL-Band (which is around 1.5 GHz). Since thepropagation conditions vary with frequency, fourDAB transmission modes are used (see Table 1).

These modes are detected automatically by thereceiver and are transparent to the user. Mode I issuitable for SFNs operating at frequencies below

3. The Eureka 147 DAB system has been refined recentlyto include very low bit rates, such as 8, 16 and 24 kbit/sper monophonic audio programme. This is made pos-sible by using a sampling frequency of 24 kbit/s, insteadof 48 kbit/s.


ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁÁÁÁÁ

Mode I ÁÁÁÁÁÁÁÁÁÁ

Mode II ÁÁÁÁÁÁÁÁÁÁ

Mode III ÁÁÁÁÁÁÁÁÁÁ

Mode IVÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Upper frequency limit (MHz)ÁÁÁÁÁÁÁÁÁÁÁÁ

300ÁÁÁÁÁÁÁÁÁÁ



1500ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Number of carriersÁÁÁÁÁÁÁÁÁÁÁÁ




768ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Carrier spacing (kHz)ÁÁÁÁÁÁÁÁÁÁÁÁ




2ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁTotal symbol duration (�s)





623ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁGuard interval duration (�s)

ÁÁÁÁÁÁÁÁÁÁÁÁ246

ÁÁÁÁÁÁÁÁÁÁ62


ÁÁÁÁÁÁÁÁÁÁ123ÁÁÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁÁÁÁFrame duration (ms)ÁÁÁÁÁÁÁÁÁÁÁÁ96




ÁÁÁÁÁÁÁÁÁÁÁSymbols per frameÁÁÁÁÁÁÁÁÁÁÁÁ76




ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Null symbol (�s)ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

1297ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

324.2ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

168ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

648.4

Notes: Ensemble bandwidth = 1.536 MHzSampling frequency = 2.048 MHz

300 MHz. Mode II has been designed for local andregional services at frequencies below 1.5 GHzand Mode III is available for satellite broadcastingbelow 3 GHz. Mode IV has recently beenintroduced to enable existing transmitter sites toprovide optimum and seamless coverage of largeareas by means of SFNs operating in L-Band. Theparameters of Mode IV lie between those of ModeI and Mode II.

6.6. Data services

Although audio has been its primary raison d’être,the Eureka 147 transmission system can also beused to carry a large variety of programme-associated and independent data services. Manydata services of the programme-associatedcategory will probably be transmitted from theoutset and will be received by the first genera-tion of DAB consumer-type receivers. Later on,independent data services may also appear. Thesewould be received by dedicated data receivers,including those incorporated in desk-top and lap-top computers. Two examples of this applicationare the electronic delivery of newspapers and thetransmission of compressed video images such asweather maps.

The Eureka system’s immunity to multipath andother reception impairments will guarantee error-free data reception in the mobile environment.Hence, the Eureka 147 system is an ideal comple-ment to the wired Information Highway distribu-tion system now being established worldwide.

Further data-transmission possibilities of DAB areoutlined in Section 18.

6.7. Future-proofing

The Eureka 147 DAB system is future-proof.Once the receiver has been purchased, it will notbecome obsolete as the digital technology devel-ops, nor as new services and applications emerge.

In Europe, for example, DAB delivery will com-mence via terrestrial networks. Nevertheless, thereceivers designed for use with these terrestrialservices should, in principle, also be able to receivefuture DAB services delivered via satellite andcable. In other words, the Eureka 147 system willbecome a universal means to deliver sound pro-grammes and data, irrespective of the transmissionmedium used4.

7. System constraints

The design of a new system is inherently a trade-off between different technical and operationalchoices. Thus, when introducing DAB services,one must be aware of the technical constraintsof the Eureka 147 system, which may generallybe overcome by the use of suitable operationalpractices.

The main technical constraints are now described.

7.1. System processing delay

The DAB system chain includes several blockswhich introduce a significant processing delay.For example, the time interleaver introduces adelay of 384 ms, and the audio coder/decoderintroduces a delay of several tens of milliseconds.The total delay in the system may vary from oneimplementation to the next.

4. Studies are now being conducted on the use of theEureka 147 system as a digital television deliverymedium for mobile reception on small screens.

Table 1Transmission modes

of the Eureka 147DAB system.


The system delay should be taken into accountwhen the receiver switches between DAB and FM“simulcast” programmes, so that a seamlesstransition is obtained. It will become necessary forsimulcast FM transmissions to be delayed bynominally the same amount, say one second,regardless of the receiver design. This nominaldelay should be taken into account when signallingthe current time information.

7.2. Frequency accuracy in SFNs

In order not to reduce the performance of theDAB system, the difference in frequency betweengeographically-adjacent transmitters must be keptto an absolute minimum – of the order of a fewhertz in 108. Consequently, the local oscillators ofall transmitters must be locked to a rubidiumoscillator, or to a common reference which isdistributed to all the transmitters.

7.3. Time accuracy in SFNs

The time difference between geographically-adjacent transmitters will have an implication onthe system’s capability to cope with “activeechoes”. Therefore, all the transmitters operating inan SFN should be time-synchronized with anaccuracy of better than 25 �s (i.e. approximately10 % of the guard interval in Transmission Mode I).

7.4. Bit-by-bit compliance in SFNs

In principle, the bit-streams emitted from all trans-mitters operating in an SFN should be identical. Ifthis condition is not fulfilled, there will be a “musharea” (i.e. interference zone) between the trans-mitters where the DAB receiver may be confused.Tests are being undertaken to assess the size ofthe mush area in the case where a local trans-mitter “opts out” from an SFN, thus emitting adifferent bit stream to the other transmitters inthe SFN.

7.5. Receiver speed limit

As the speed of a vehicle increases, the per-formance of an on-board DAB receiver progres-sively degrades, due to the Doppler effect. The“receiver speed limit” may be considered as thevehicular speed at which the RF signal-to-noiseratio degrades by 4 dB, due to the Doppler effect.While this does not affect the audio quality, it mayreduce the DAB coverage area slightly – but onlyin a fast-moving vehicle.

In the case of an SFN operating at VHF, thereceiver speed limit is about 200 km/h. When the

receiver operates at 1.5 GHz and TransmissionMode IV is used, the speed limit is about 120 km/h.

8. Standardization

A common transmission standard for DAB, asopposed to a multitude of proprietory standards,has always been preferred by EBU Members. Asingle standard would readily lead to the massproduction of DAB receivers, bringing their pricesdown to an affordable level. It would open thedoor to free market competition, resulting in awide variety of receiver brands offering a range ofqualities and features. A unique DAB standardwould mean that the same core electronic circuitryin the receiver could be used in all parts of theworld, as is the case today with AM and FM radio.It would also reduce the need to perform standardsconversion with its inherent degradation of thesignal. A single DAB standard would introducestability in the market and the DAB technologywould last for a long time.

In pursuing the above objectives, the EBU hasbeen instrumental in establishing a unique DABstandard at both the European and the worldwidelevels.

8.1. ETSI

In late 1994, the Eureka 147 DAB system wasadopted by ETSI5 as a European Standard. ETSIthen published the standard – ETS 300 401 [4] – inFebruary 1995.

The ETSI Standard describes the technical detailsof the broadcast on-air signal and is applicable toterrestrial, satellite and cable delivery, in all thefrequency bands that are available for broadcast-ing above 30 MHz. The concept of the Standardis such that it includes both mandatory andoptional features of the system, and it allows forfuture functional refinements and additions by theapplication of appropriate software tools. TheStandard permits different levels of implement-ation to meet a variety of market requirements,production costs and receiver types.

8.2. ITU

The global DAB standardization process is beingconducted within the International Telecommuni-cation Union (ITU) which, among other things,considers new developments in broadcastingtechnology and agrees the technical standards ofbroadcasting systems – for both radio and televi-

5. European Telecommunication Standards Institute.


sion – on a worldwide basis. Over the years, EBUMembers have contributed extensively to differentITU working parties on the results of R&D workcarried out in their own laboratories.

Since 1985, the ITU-R6 has studied proposals fornew digital sound broadcasting systems – for bothsatellite and terrestrial delivery to vehicular,portable and fixed receivers in the frequency range30 – 3000 MHz. This information has beenincluded in Report 955 for satellite sound broad-casting [5] and Report 1203 for terrestrial soundbroadcasting [6]. Both reports still provide usefulbackground information for analogue and digitalsystem characteristics and frequency planningconsiderations, but they are now being supersededby a new ITU-R Special Publication on DigitalSound Broadcasting (see Section 8.2.4.).

Since 1987, the ITU-R has been attempting toagree on the technical and operational require-ments that any digital sound broadcasting systemshould fulfill. In November 1991, Working Parties10B and 10-11S adopted two new draft Recom-mendations on the system and service require-ments. These Recommendations were slightlyrevised in November/December 1994 [7], [8].

Two important requirements should be high-lighted here:

a) the satellite and the terrestrial systems shouldboth provide significantly-improved perfor-mance in a multipath and shadowing environ-ment, when compared with existing analoguesystems;

b) the satellite and the terrestrial systems shouldboth be capable of utilizing common signal-processing circuits in the receivers.

8.2.1. Digital Systems A and B

The most important ITU-R effort for some yearshas been focused on agreeing a Recommendationon the sound broadcasting system itself. TheEureka 147 system – known in ITU parlance asDigital System A – was first recommended byWorking Party 10B (as a terrestrial system) andby Working Party 10-11S (as a satellite system)in October 1993, but only provisionally. A formalRecommendation was not possible at that timebecause some delegates wished to await the suc-cessful outcome of tests being conducted by theUS Electronic Industry Association (EIA) on theso-called “IBOC” and “IBAC” approaches (see

6. ITU Radiocommunications Sector, formerly known asthe CCIR.

Section 14.), and on the satellite system proposedjointly by the Voice of America and the Jet Propul-sion Laboratory, known as ITU-R Digital System B.These tests were originally planned to finish by theend of 1994 but the estimated completion date hasnow slipped back until well into 1996.

8.2.2. A common worldwide standardfor digital radio

At the late-1994 meetings of ITU-R WorkingParties 10B and 10-11S, it was decided unani-mously to adopt two Draft Recommendations,BS.1114 [9] and BO.1130 [10]. The first of thesedrafts recommends to ITU members to use DigitalSystem A for terrestrial delivery in the frequencyrange 30 – 3000 MHz. The second one recom-mends that administrations wishing, in the nearfuture, to implement BSS (sound) which meetssome or all of the requirements stated in ITU-RRecommendation BO.789 should consider the useof Digital System A.

Both these Draft Recommendations include aNote which, in principle, opens the door to othersystems as well – when they are sufficientlydeveloped and tested, and when they have shownthat they would meet the agreed and approvedITU requirements given in Recommendations774 or 789 (for terrestrial and satellite systems,respectively).

It was only possible for the ITU to adopt the abovetwo Draft Recommendations because the EBUwas able to present important evidence to thelate-1994 meetings of Working Parties 10B and10-11S. This evidence included a final Eureka 147system specification (corresponding to the ETSIstandard), as well as comprehensive EBU evalua-tions on the RF performance characteristics ofDAB (including the subjective audio qualityversus the RF signal-to-noise ratio) and the inter-ference protection ratios required to protect otherservices in the same or the adjacent bands, or toprotect DAB services themselves. In addition,many administrations were able to present theresults of their own field tests and experiments.

The achievement of a common worldwide Stan-dard is rare in the history of broadcasting. In thecase of the Eureka 147 system, it was only possibledue to the joint efforts of, and extensive coopera-tion between, European and Canadian broadcast-ers, research institutes and the radio manufactur-ing industry. The Eureka system also had thesupport of many administrations outside Europe,particularly from the developing countries.


It should be pointed out that, so far, no other digitalradio system submitted to the ITU has been able toachieve the level of success of the Eureka 147system. However, the situation may changewhen, or if, other systems reach a level of mat-urity that is comparable to the present Eureka 147system; the proponents of these new systemscould then knock at the door of the ITU and claimworldwide recognition as well!

8.2.3. A common worldwide standardfor audio compression

Following extensive subjective tests, ITU-R TaskGroup 10/2 has adopted for emission the ISO/MPEG Layer II format at 256 kbit/s.

This audio bit-rate reduction system has beendeveloped and implemented within the Eureka 147Project and is known as Musicam. It uses a rangeof bit rates between 8 and 192 kbit/s per mono-phonic channel to allow some flexibility in opti-mizing the trade-off between the intrinsic audioquality and the service ruggedness. A high-qualitystereo channel will generally use bit rates at thehigher end of the range, e.g. 2 x 96 kbit/s.

8.2.4. ITU Special Publication on DigitalSound Broadcasting

The ITU-R has prepared a Special Publication onDigital Sound Broadcasting [11]. This compre-hensive book is based on the studies performedsince 1991 by ITU-R Working Parties 10B and10-11S, and covers both terrestrial and satellitedigital sound broadcasting. It contains a theo-retical part on the different systems, a section onfrequency planning approaches and experimentalevidence derived from laboratory and field testscarried out on the different systems.

This ITU-R Special Publication is particularly use-ful to those who are planning DSB services in thenear future, but it may also be interesting for thosewho have a medium- to long-term interest in DSBservices, particularly in the developing countries.

8.3. CENELEC

CENELEC7 is planning to release a receiver stan-dard for Eureka 147 DAB, by the end of 1995.Based on a draft technical report already preparedby EACEM8 [12], the CENELEC Standard will

7. European Committee for Electrotechnical Standardiza-tion.

8. European Association of Consumer ElectronicsManufacturers.

define only those mandatory parameters which arenecessary for Eureka 147 DAB receivers to inter-pret correctly the received signals; non-mandatoryparameters will not be specified and may be opento competition in the marketplace.

A specification of the receiver data interface (RDI)of the Eureka 147 system has been drawn up andwill be converted into a CENELEC EuropeanStandard in due course. Via the RDI, it will bepossible to connect computers, printers and dedi-cated decoders for data applications, as well asdevices for audio post-processing and recording.

9. Role of the EBU

EBU Members have long been in agreement thata new digital radio broadcasting system should bedesigned to supersede AM and FM analoguetechnology. Towards this end, they were instru-mental in initiating a series of studies in 1985,initially on satellite DAB aspects.

It was soon realised that EBU Members would notbe able to design and develop a new system bythemselves. Cooperation with the manufacturersand with national administrations would be neces-sary. Hence, the Eureka 147 Consortium was setup in 1987 and has been actively supported byEBU Members ever since. In order to guide theEureka 147 Consortium, EBU Members initiallydrafted the user requirements with which the newsystem should comply. Although the EBU, as anassociation of broadcasters, could not become aformal member of the Eureka 147 Consortium,many EBU member organizations individuallyjoined the Eureka 147 Project. Furthermore, theEBU Technical Department actively participatedin the deliberations taking place within the Eurekaworking bodies.

The EBU has actively supported the promotion ofthe Eureka 147 system; many demonstrations havebeen organized jointly with the Eureka 147 Con-sortium. In particular, the EBU was instrumentalin promoting the Eureka 147 system within theITU and at the World Conference of BroadcastingUnions. The EBU also organized the work whichled to the establishment of the ETSI EuropeanStandard on DAB.

In April 1994, the EBU Technical Committeeadopted EBU Recommendation R79-1994 [13].This document recommends the Eureka 147system for terrestrial and satellite delivery of DABservices. An EBU Working Party, set up toevaluate the DAB system, prepared a comprehen-sive technical document on baseband and radio-


frequency performance of the system, and theprotection ratios required. Based on this informa-tion, it was possible to establish the sharing criteriafor DAB services and other services using thesame or the adjacent frequency bands.

9.1. Project Groups

As described in the previous issue of EBU

Technical Review [14], the EBU will sooncomplete a major reorganization of its workinggroups in order to improve the efficiency of theirstudies and to speed up the approval procedures.Work is now entrusted to a limited number ofProject Groups, comprising a minimum number ofexperts. Each Group is assigned a specific task tobe accomplished within a limited time-frame.

The following Project Groups – all operating with-in the EBU Broadcast Management Committee –are involved in different aspects of DAB:

– B/DAC (DAB Characterization and Evalua-tion);

– B/TAP (Terrestrial Audio Planning);

– B/INB (International Broadcasting);

– B/DSI (Detailed Spectrum Investigation);

– B/PPD (Propagation Predictions for DigitalServices).

9.2. Guidelines for implementationand operation

Based on the work carried out by the Eureka 147Project Group, the EBU is planning to publishGuidelines for Implementation and Operation [15]as a companion to the ETS 300 401 Standard.This document – which is extremely importantfor EBU Members who wish to start DAB ser-vices – is intended to provide additional in-formation on the system, to aid interpretation ofon-air signals conforming to the ETSI Standard,and to assist the broadcasters and manufacturersto implement systems using the specificationfeatures as intended.

9.3. Interfaces

Two interface-related DAB standards, producedwithin the framework of the Eureka 147 DAB proj-ect, are very important for broadcasters. The firstone, Ensemble Transport Interface (ETI) [16], hasalready been issued by the EBU. The second one,entitled Service Transport Interface, will be com-pleted by the Eureka 147 Consortium this autumn.

9.4. Frequency planning

One area of the EBU’s DAB activity which mustbe highlighted is its contribution to the CEPT9 onfrequency planning matters. On behalf of theCEPT, the EBU was responsible for coordinatingthe preparations for the CEPT Planning Meetingon terrestrial DAB services, held during July 1995in Wiesbaden, Germany (see Section 11., and alsothe article starting on page 28 [17]).

The EBU issued a Technical Document [18] inJune 1995 which considers all the major elementsof network planning, network concepts and themain planning parameters to be taken into account(such as protection ratios, necessary field strengthsand coordination parameters).

10. EuroDab Forum

In order to stimulate the transfer of technologyfrom the laboratory to the marketplace, and fol-lowing the proposal of several existing nationalforums, a European DAB Forum – EuroDab – hasbeen set up. The aim of the EuroDab Forum is alsoto harmonize the activities of national DAB plat-forms and to encourage the establishment of newnational groupings in those countries which havenot yet organized their activities on DAB. TheEuroDab Forum should be able to capitalize on thetremendous achievement of the Eureka 147 DABProject and to bring Digital System A to commonpractice. It should also encourage cooperation,firstly at a European level but eventually world-wide, and try to avoid duplication of work withinthe national groupings.

The first meeting of the EuroDab Forum, held inGeneva during March 1995, was unanimous inagreeing upon the principal objective of the Euro-Dab Forum – to create in Europe and in other partsof the world a framework for a harmonious andmarket-driven development of DAB servicesusing the terrestrial, cable and satellite broadcast-ing infrastructure. All major national groupings onDAB – including broadcasters, service providersand the manufacturing industry – were representedat the meeting.

A number of possible areas of activities have beenidentified, including:

– audio programming issues;

– programme-associated and independent dataservices;

9. European Conference of Postal and Telecommunica-tions Administrations.


– marketing issues and a strategy for the introduc-tion of DAB services;

– coordination of business plans;

– minimum requirements and optional character-istics of DAB receivers;

– legal and regulatory matters;

– monitoring of standardization activities;

– future evolution towards multimedia and inter-active radio.

The EuroDab Forum will organize conferences,seminars and symposia on DAB and will launchstudies, surveys and analyses on DAB markets.Initially, five working groups will be set up,covering the following topics:

– equipment;

– regulatory matters;

– marketing and promotion;

– services;

– satellite services.

The EuroDab Forum is open to potential membersfrom all parts of the world. Since March 1995,more than 70 national forums, manufacturers,broadcasters, network providers, media regulatorsand administrations have joined the Forum – andthe number is still increasing. Broadcasters,administrations and manufacturers from Canada,Australia, India, China, Mexico and other non-European countries have also expressed an interestin joining EuroDab.

Perhaps there is already a need to change thename from EuroDab to “WorldDab”, or somethingsimilar!

11. Spectrum issues

A three-week Planning Meeting was convened inJuly 1995 by the CEPT (see the article starting onpage 28). The aim of this Meeting was to producea Special Arrangement for the introduction ofterrestrial transmissions of the Eureka 147 DABsystem in the frequency bands 46 – 68 MHz,174 – 240 MHz and 1452 – 1467.5 MHz, as wellas to prepare an associated Frequency Block Allot-ment Plan, taking into account the final require-ments of the CEPT member countries. A fullreport on this CEPT meeting will appear in a futureissue of EBU Technical Review.

Briefly, the Allotment Plan drawn up at the Meet-ing provides practically all the member countriesof the CEPT with two sets of frequency blocks,each of width 1.536 MHz. This is a vital pre-requisite to the wide-scale launch of terrestrialDAB services in Europe. Most of the CEPTcountries opted for frequency block allotments inVHF Band III and in L-Band.

Table 2 gives a list of the 85 frequency blockswhich, potentially, can be used for current andfuture DAB services in Europe. The distributionof these frequency blocks is as follows:

– 12 blocks in VHF Band I (47 – 68 MHz);

– 38 blocks in VHF Band III (174 MHz –240 MHz);

– 23 blocks in L-Band (1452 – 1492 MHz);

– 12 blocks in VHF Band II (87 – 108 MHz).

DAB block numbers 1 to 59 correspond with theCEPT proposal put to the Meeting; blocks 60 to 85have been added to the Plan by the EBU.

Each frequency block carries a two- or three-character label, which is easier to remember thanthe centre frequency of the block, and which isconvenient for receiver manufacturers and con-sumers to use when initially programming theirreceivers.

The labelling system of the frequency blocks inVHF Band I and Band III is fully compatible withthe existing VHF television channel numbers (i.e.Channels 2 to 13). Each of these televisionchannels can accommodate four DAB blocks; sixblocks in the case of Channel 13.

All the frequencies listed in the table comply withthe 16 kHz raster as specified in the ETS 300 401Standard.

One of the important results of the Meeting wasa definition of the centre frequency of eachensemble (i.e. frequency block). This informationis very important for receiver manufacturers andmay help substantially to simplify the receiverdesign; before the Meeting, any frequency in the16 kHz raster could be used as the centre fre-quency, resulting in a very large number of possi-bilities. The number of defined centre frequencieshas now been reduced to match the total number ofensembles allocated in Band III and in L-Band(i.e. 61). These centre frequencies are likely tobe implemented in the first-generation DABreceivers manufactured for the European market.


ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Frequencyband

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

DABblock number

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Frequencyblock label


Centrefrequency

(MHz)


Lowerlimit

(MHz)


Upperlimit

(MHz)ÁÁÁÁÁÁÁÁÁÁÁÁÁÁ


01 ÁÁÁÁÁÁÁÁÁÁ

2A ÁÁÁÁÁÁÁÁÁÁÁÁ

47.936 ÁÁÁÁÁÁÁÁ

47.168 ÁÁÁÁÁÁÁÁÁÁ

48.704

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁ



2B ÁÁÁÁÁÁÁÁÁÁÁÁ



50.416




2C ÁÁÁÁÁÁÁÁÁÁÁÁ



52.128

ÁÁÁÁÁÁÁÁÁÁÁÁÁ04 ÁÁÁÁÁ2D ÁÁÁÁÁÁ53.072 ÁÁÁÁ52.304 ÁÁÁÁÁ53.840ÁÁÁÁÁÁÁÁÁÁÁÁÁÁ


ÁÁÁÁÁÁÁÁÁÁ3A

ÁÁÁÁÁÁÁÁÁÁÁÁ54.928

ÁÁÁÁÁÁÁÁ54.160

ÁÁÁÁÁÁÁÁÁÁ55.696ÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁVHF



3BÁÁÁÁÁÁÁÁÁÁÁÁ

56.640ÁÁÁÁÁÁÁÁ

55.872ÁÁÁÁÁÁÁÁÁÁ

57.408ÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Band I ÁÁÁÁÁÁÁÁÁÁÁÁ





59.120




3D ÁÁÁÁÁÁÁÁÁÁÁÁ



60.832







62.704

ÁÁÁÁÁÁÁÁÁÁÁÁÁ10 ÁÁÁÁÁ4B ÁÁÁÁÁÁ63.648 ÁÁÁÁ62.880 ÁÁÁÁÁ64.416ÁÁÁÁÁÁÁÁÁÁÁÁÁÁ


ÁÁÁÁÁÁÁÁÁÁ4C




ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ


4DÁÁÁÁÁÁÁÁÁÁÁÁ









174.696







177.408







179.120

ÁÁÁÁÁÁÁÁÁÁÁÁÁ16 ÁÁÁÁÁ5D ÁÁÁÁÁÁ180.064 ÁÁÁÁ179.296ÁÁÁÁÁ180.832ÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

















186.128







187.840







189.696

ÁÁÁÁÁÁÁÁÁÁÁÁÁ22 ÁÁÁÁÁ7B ÁÁÁÁÁÁ190.640 ÁÁÁÁ189.872ÁÁÁÁÁ191.408ÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

















196.704







198.416







200.128













VHF ÁÁÁÁÁÁÁÁÁÁÁÁ





207.120


Band III ÁÁÁÁÁÁÁÁÁÁÁÁ





208.832







210.704


















217.696







219.408







221.120


















228.128







229.840







231.552















13E ÁÁÁÁÁÁÁÁÁÁÁÁ



238.256




13F ÁÁÁÁÁÁÁÁÁÁÁÁ



239.968

Table 2aDAB frequencyblocks: 01 – 50.



Frequencyband


DABblock number


Frequencyblock label


Centrefrequency

(MHz)


Lowerlimit

(MHz)


Upperlimit

(MHz)ÁÁÁÁÁÁÁÁÁÁÁÁ


51 ÁÁÁÁÁÁÁÁÁÁÁÁ

L1 ÁÁÁÁÁÁÁÁÁÁ



1453.728







1455.440







1457.152

ÁÁÁÁÁÁÁÁÁÁÁÁ54 ÁÁÁÁÁÁL4 ÁÁÁÁÁ1458.096 ÁÁÁÁÁ1457.328 ÁÁÁÁ1458.864ÁÁÁÁÁÁÁÁÁÁÁÁ


55ÁÁÁÁÁÁÁÁÁÁÁÁ

L5ÁÁÁÁÁÁÁÁÁÁ



1460.576ÁÁÁÁÁÁÁÁÁÁÁÁ












1464.000







1465.712



ÁÁÁÁÁÁÁÁÁÁÁÁL10

ÁÁÁÁÁÁÁÁÁÁ1468.368


ÁÁÁÁÁÁÁÁ1469.136ÁÁÁÁÁÁ







L-Band ÁÁÁÁÁÁÁÁÁÁÁÁ





1472.560







1474.272







1475.984



















1482.832







1484.544



ÁÁÁÁÁÁÁÁÁÁÁÁL21















1491.392




F1 ÁÁÁÁÁÁÁÁÁÁ



88.704







90.416

ÁÁÁÁÁÁÁÁÁÁÁÁ76 ÁÁÁÁÁÁF3 ÁÁÁÁÁ91.360 ÁÁÁÁÁ90.592 ÁÁÁÁ92.128ÁÁÁÁÁÁÁÁÁÁÁÁ



F4ÁÁÁÁÁÁÁÁÁÁ









95.696


VHF ÁÁÁÁÁÁÁÁÁÁÁÁ





97.408


Band II ÁÁÁÁÁÁÁÁÁÁÁÁ





99.120

ÁÁÁÁÁÁÁÁÁÁÁÁ81 ÁÁÁÁÁÁF8 ÁÁÁÁÁ100.064 ÁÁÁÁÁ99.296 ÁÁÁÁ100.832ÁÁÁÁÁÁÁÁÁÁÁÁ


ÁÁÁÁÁÁÁÁÁÁÁÁF9






F10ÁÁÁÁÁÁÁÁÁÁ









106.128







107.840

12. European strategies for theintroduction of DAB services

Currently, many pilot service trials and field testsat VHF and in L-Band are being conducted all overEurope. In many countries there are plans tocommence pre-operational terrestrial services thisyear or in 1996/7, primarily making use of theexisting transmitter and distribution infrastruc-ture10. Although the situation varies very muchfrom country to country, it is clear that the critical

10. The world’s first official DAB services were inaugu-rated in the UK by BBC Radio, and in Sweden by theSwedish Broadcasting Corporation, on 27 September1995.

mass has already been achieved and that theintroduction of the Eureka 147 DAB system inEurope is assured.

The following is a short summary of national plansfor the introduction of DAB services, as well asprogress on DAB experimental and promotionalactivities throughout Europe. It is recognized thatthis summary may not be completely up-to-date,such is the pace of DAB implementation.

12.1. Belgium

In Belgium, audiovisual and broadcasting matters(including those which relate to DAB) are consid-ered at the level of the different cultural communi-ties (Flemish, French and German). Therefore a

Table 2bDAB frequencyblocks: 51 – 85.


national DAB forum cannot be established at thefederal level.

Nevertheless, an informal coordination group hasbeen set up at the federal level to address the issueswhich relate to DAB and other radio matters. Thisgroup includes all the interested parties through-out the country (broadcasters, network providers,manufacturers, cable operators, administrators,etc.). Some key players such as the Flemish-language public broadcaster, BRTN, and theFrench-language public broadcaster, RTBF, havebecome direct members of the EuroDab Forum.

The BRTN is planning to start pre-operationalDAB services at the end of 1997.

12.2. Denmark

Denmark is in the process of setting up a nationalDAB platform.

The National Telecom Agency has already de-cided to allocate one or two VHF frequencyblocks (225 to 230 MHz) for national SFNs, andtwo or three blocks (235 to 240 MHz) for regionalnetworks. The L-Band between 1452 and1467.5 MHz has been allocated for local servicesand the number of frequency blocks here has yetto be decided. In the Faeroe Islands, the frequencyranges 223 – 230 MHz and 235 – 240 MHz will beused.

In September 1994, a DAB transmitter of 500 We.r.p. began tests at 237 MHz in Copenhagen. InSeptember 1995, the test frequency was changedto 227.360 MHz, following the CEPT PlanningMeeting (see Section 11.). However, the transmis-sions on this new frequency have caused problemsto the local Channel 12 cable television servicesand so the tests have now reverted to 237 MHz.

Further experiments are planned in Western Jut-land during 1996, to test an SFN network consist-ing of four 1 kW e.r.p. transmitters.

Danish Radio is planning to distribute some 500receivers for a controlled evaluation of DAB, assoon as the financial details have been agreed.

12.3. Finland

The Finnish national DAB platform has beenworking for some months.

The YLE started experimental transmissions inFebruary 1994 on 105 MHz in Helsinki. Twotransmitters of 2.5 and 0.8 kW e.r.p. are used.

Problems in urban areas have been encounteredwith horizontal polarization, due to high levels ofman-made noise. Further tests in Band III are fore-seen. The Finnish manufacturing industry is de-veloping a combined terrestrial/satellite DAB re-ceiver, in cooperation with the European SpaceAgency (ESA).

12.4. France

The French DAB Club was established in autumn1991. It comprises the French regulator (CSA),public and private broadcasters, professional andconsumer manufacturers, and others. The activi-ties of the DAB Club are diverse and include thepromotion of DAB, communication with otherDAB groupings, coordination of trials and experi-ments, etc. The French DAB Club has conductedexperiments in Paris, both in VHF Band I and inL-Band, and has chosen in favour of L-Band.

Radio France has established a Working Party onradio programming issues, to study which specificprogrammes would be particularly suitable forDAB broadcasts. Radio France has also signed anagreement with TDF to provide DAB coverage ofall major metropolitan areas and motorways (i.e.25 % of the population) as soon as consumerreceivers are available.

TDF is fostering close partnerships with bothcurrent and potential customers in order to defineinnovative multimedia applications of the DABsystem. TDF has created a new “Infodiffusion”department, which is responsible for on-line andmultimedia applications, and which aims to sup-port the development of new services deliveredover the air. In order to move into the consumersegment, TDF will team up with leading serviceproviders to launch pilot services. These will bedesigned to assess and define the demand in keytarget markets such as interactive television (inconjunction with Television France and Matra-Hatchette), new radio-related services (with RadioFrance), electronic newspaper publishing (withLe Monde and Le Républicain Lorrain) and ser-vices for mobile users in conjunction with theFrench transport ministry and the City of Paris.

12.5. Germany

The German national DAB platform was formedin 1991 and consists of public and private broad-casters, manufacturers, R&D institutions, PTT/Telecom operators and others. Recently, it estab-lished a Memorandum of Understanding whichconcerns two principal points:

a) the implementation of pilot projects in severalLänder and the carrying out of experiments;


b) the introduction of regular DAB services intime for the Berlin IFA11 fair in 1997 and theachievement of near-complete coverage ofGermany by the year 2000.

Among the pilot projects currently undertaken orin preparation are those in Baden-Württemberg,Bavaria, Berlin, Hessen, Lower Saxony, Meck-lenburg-Western Pomeriana, North-Rhein West-phalia, Rheinland-Palatine, Saxony, Saxony-Anhalt, Thuringia and the border of Germany withSwitzerland in the Lörrach and Basel area.

In total, some 20 000 to 25 000 receivers, pro-duced mainly by German receiver manufacturers,will be used to test technical and programmingfeatures of the DAB system. The funding is pro-vided in part by the States Governments. The mainorganizations involved in organizing these testsare: the IRT, DBP-Telekom, media authorities,regional broadcasters and some manufacturers.Both Band III (Channel 12) and L-Band are beingconsidered.

The German platform is cooperating with neigh-bouring countries and has invited them to test DABequipment and gain experience.

12.6. Hungary

The Hungarian DAB Group started in 1992 andincludes all important entities in the field of DAB.

In autumn 1995, a DAB experiment using onetransmitter will be installed in Budapest, carryingfive different programmes and data. Regular DABservices will most probably start in 1997. How-ever, the availability of DAB receivers in sufficientvolumes, and at affordable prices, is a key issue.

12.7. Italy

In Italy, several experimental activities are on-going. RAI is completing the development of aDAB test-bed in the Aosta Valley, which currentlyconsists of three transmitters operating as an SFNin VHF Channel 12. An extension to four trans-mitters is foreseen. The band 223 – 230 MHz hasbeen identified for DAB services but has not yetbeen fully approved. There is some chance thatL-Band could also be used.

12.8. The Netherlands

The Dutch national DAB platform has alreadybeen established.

11. Internationale Funkausstellung.

A frequency range 216 – 230 MHz has been identi-fied, but not yet selected, to accommodate onefrequency block for national services and fourblocks for regional DAB services. L-Band may beused for local services.

Tests with an SFN are being carried out byNOZEMA in Haarlem, Hilversum and Rotterdam.In total, four transmitters operating in VHF BandIII (Channel 12) provide 40 % coverage of theDutch population. In order to increase the spec-trum efficiency of DAB services (e.g. 16 stereoprogrammes per frequency block), extremely lowcoding rates (64 kbit/s and less per stereophonicprogramme) are of great interest. The Dutchexperiments, which involve seven companies,include the datacasting of an electronic news-paper, company information, railway and travelinformation, etc. Recently, DAB was the subjectof governmental auditing.

12.9. Norway

The Norwegian DAB Group has been in existencesince 1990.

The first DAB transmitter was installed by Telenorand NRK in Oslo during April 1994. There are twotransmitters at present, operating as an SFN, and athird transmitter will be added soon. A fourthtransmitter will be installed in Trondheim, whichlies in a very mountainous region. The tests in-clude coverage evaluations in mountainous areasand the evaluation of programme-feed techniques.

12.10. Poland

There are plans to establish a national DAB group-ing in Poland. In Warsaw, an experimental DABservice may commence at the end of 1995.

12.11. Sweden

As a result of the collaborative efforts of Teracomand Swedish Radio, the first DAB experimentsstarted in March 1992, covering the Stockholmarea. An SFN experiment in Uppsala/Enköping,comprising three stations, started in March 1994and it now has four DAB transmitters in operation.

An official DAB service was introduced in theStockholm area on 27 September 1995. This willbe followed by the opening of three SFNs in Stock-holm, Gothenburg and Malmö as soon as possible.One additional SFN may be introduced in a ruralregion, thus extending DAB coverage to 35 % ofthe population in 1996. Limited governmentalsupport might be provided. In addition to theSwedish radio channels, which include a new


classical music programme, there will be a pro-gramme in Finnish and a channel for Lapps. Newdata services will be tested also.

12.12. Switzerland

The Swiss national DAB platform has existed fornearly two years. For future DAB services, fourfrequency blocks will be allocated in VHF Chan-nel 12 and a further nine blocks will be made avail-able in L-Band (1452 – 1467 MHz).

Swiss Télécom PTT is currently operating twoSFNs, one in VHF Channel 12 and the other inL-Band. The Channel 12 tests in the Reuss Valleystarted in June 1993 and initially comprised twotransmitters. In the same region, a trial in L-Bandstarted in May 1994.

Tests in the Bernese Oberland area started in Aprilthis year, using three transmitters in Channel 12.This trial is planned to become a pilot project inOctober 1995 which will continue for a period oftwo years. The official introduction of DAB ser-vices in Switzerland is planned for 1997.

12.13. United Kingdom

The UK national DAB Forum has been establishedsince 1992.

Last year, the UK government allocated 12.5 MHzof radio spectrum in VHF Band III. This providesspace for seven DAB frequency blocks. Each ofthose can carry an ensemble of six high-qualitystereo channels plus some data, or different com-binations of audio and data services depending onthe bit rates used. Of the seven frequency blocks,one has been allocated to the BBC for a nationalnetwork. A second will be used for national com-mercial radio services, yet to be decided by the UKregulatory body (the Radio Authority). The otherfive blocks will be used for local and regional BBCand independent radio services.

The BBC launched its official DAB service on27 September 1995. Initially, an SFN of five trans-mitters serves a large area of south-east England(about 20 % of the UK population). Within two-and-a-half years, 27 transmitters will cover about60 % of the UK population and will include themain motorway and trunk road network.

The BBC is “simulcasting” (i.e. simultaneouslybroadcasting) its five current national channels onDAB and will also introduce a number of newservices. It plans to use the multiplex dynamically,varying the bit rate according to the programme

content and the number of services available atany given time. The normal data rate is expectedto be between 96 and 128 kbit/s per monophonicchannel, reducing to a minimum of 64 kbit/s forsome spoken material.

A new monophonic announcement channel isbeing considered, to be transmitted at 64 kbit/s. Itwill provide short spoken messages, each ofaround two to three minutes duration, which willbe transmitted cyclically every ten minutes or so.These will be supported by the Announcementsfeature, within a BBC cluster, whenever newmessages are introduced. Messages which are notnew, but which remain relevant, will be assignedprogramme type (PTY) codes so that specifictypes of message may be requested on demand.

In August 1995, the UK Government issued aWhite Paper entitled Digital Terrestrial Broadcast-ing. This document outlines proposals for a newlegislative framework for allocating the use of thespectrum and for licensing and regulating the trans-mission of both television and sound radio broad-cast services. Comments or views on these propos-als are awaited for early October 1995. Inparticular, the role of the multiplex provider isdefined; this is considered very important for thedevelopment of the audio-visual broadcast market.

13. International strategies forthe introduction of digitalradio

Outside Europe, extensive field trials and com-puter simulations have also been conducted onDAB, primarily in Canada but also in Australiaand the USA.

13.1. Australia

To further the awareness of the Australian broad-cast industry concerning digital radio matters, theAustralian administration has implemented an on-going series of demonstrations and investigationsin L-Band. These are based on the Eureka 147DAB system. During 1994, terrestrial demonstra-tions of DAB were held in Canberra and Sydneyand, in June 1995, the first L-Band satellite trialinvolving the Eureka 147 system was undertakenusing the Australian Optus B3 satellite. Theresults of these tests have been presented to theSeptember 1995 meeting of ITU-R Working Party10-11S.

More recently, the Australian administrationannounced a major initiative to fund DAB trans-mitter facilities in three capital cities. This will


allow the local broadcast industries to investigateoperational and practical implementation issuesassociated with digital radio. In conjunction witha similar initiative by the national telecommunica-tions carrier (TELSTRA), it is likely that exper-imental DAB facilities will be provided in Sydneyand Melbourne by the end of 1996.

13.2. Canada

The first public demonstrations in Canada usingthe Eureka DAB 147 system were conducted in1990. Digital Radio Research Inc. (DRRI) wasthen set up in 1993 to coordinate Canadian testson digital radio systems. In 1994, Canada hostedthe Second International DAB symposium inToronto.

There are four sites where DAB experiments arecurrently being conducted in L-Band – Toronto/Barrie, Trois Rivières, Montreal and Toronto –which cover more than 25 % of the Canadianpopulation. A datacasting demonstration has beengiven over this network, featuring a route-guidance system developed by the Ministry ofTransport of Ontario. New transmitters coveringOttawa and Vancouver were due to open bysummer 1995, thus extending DAB coverage to35 % of the Canadian population. Commercialoperation will begin in 1996.

Canada is currently in the process of officiallyadopting the Eureka 147 DAB system.

13.3. China

In cooperation with the European Commission andthe German national DAB platform, the Eureka147 DAB system will be used in terrestrial experi-ments in China, starting in December 1995.

13.4. India

Terrestrial DAB transmissions in India will be inVHF Band II and the satellite emissions will be inL-Band. Attempts to bring together all the majorparties involved in DAB are being pursued by AllIndia Radio and membership of the EuroDabForum is being sought.

DAB services in India will be implemented inthree phases. In the first phase, due to commencein 1998, a limited terrestrial DAB service – basedon current regional radio programmes – will beinitiated in four metropolitan cities: Delhi, Bom-bay, Calcutta and Madras. The regional pro-grammes will be collected at New Delhi, via satel-lite contribution links, and subsequently

distributed from New Delhi via an S-band trans-ponder of the INSAT satellite. The received DABsignals will be converted to VHF Band II frequen-cies and then simulcast using the existing FMtransmitting antennas and towers. In the secondphase, independent local services – carrying a mixof local, regional, national and sponsored pro-grammes – will be added gradually to a number ofFM stations by the year 2003. Finally, DAB ser-vices via satellite could commence after 2003.

So far, a number of preliminary propagationstudies have been carried out in L-Band. Experi-ments using the Eureka 147 system will startshortly, covering both terrestrial and satellitedelivery.

13.5. Mexico

A highly successful terrestrial test and demonstra-tion of the Eureka 147 DAB system was conductedat L-Band in Mexico City during 1993. Then, inJuly 1995, an L-Band satellite trial was conductedusing the Solidaridad 2 satellite. In the latter case,only low satellite power was available (about 43.5dBW). Although this gave insufficient propaga-tion margin for mobile reception at speeds of great-er than 60 km/h, both fixed and mobile receptionwere demonstrated with an antenna of gain 7 dBi.Fixed reception with a 15-dBi antenna enabled thecharacteristics of the satellite channel to be defined– while successfully operating it in all the trans-mission modes of the Eureka 147 system. At highelevation angles, Doppler effects were less of aproblem than for terrestrial transmissions, and thusMode-II operation via the satellite was shown to bemore than adequate.

13.6. The USA

A number of mobile tests and demonstrations ofdigital radio were given in the USA in 1991. Since1992, the Eureka 147 system has undergoneformal evaluation in a public test programme,along with several “in-band” digital proposals.The recently-published results of these tests arediscussed in the next Section.

14. EIA tests in the USA

Independent laboratory tests on the Eureka 147system have been conducted in the USA by theElectronics Industry Association (EIA), inassociation with the National Radio System Com-mittee (NRSC). The results of these tests werepresented during August 1995 in Monterey,California [19].


14.1. In-band proposals

In addition to the Eureka 147 system, the EIA testshave included five proponents of the so-called“in-band” concept, whereby the digital radio sig-nals are transmitted in the same band as the currentanalogue services; the digital signals areeffectively overlaid on the existing analogue sig-nals. Two variants of the concept have been pro-posed: in-band on-channel (IBOC) and in-bandadjacent-channel (IBAC).

The in-band proposals outlined in the EIA tests aregenerally of a very complex design and useadvanced digital technology which is used inmodern military applications for the professionalmarket. Therefore it is likely that “in-band”receivers will be quite expensive. From the spec-trum management viewpoint, the in-band digitalsystems currently being proposed in the USA aredesigned to overlay analogue signals where thechannel spacing is 200 kHz. These systems are notdirectly applicable to Europe where the channelspacing in VHF Band II is only 100 kHz.

The following in-band systems were tested in thelaboratory by the EIA (one AM-overlaid systemand four FM-overlaid systems):

- USADR-AM (0.54 – 1.7 MHz) IBOC

- AT&T (FM band) IBAC

- AT&T Amati (FM band) IBOC

- USADR FM1 (FM band) IBOC

- USADR FM2 (FM band) IBOC

The main characteristics of the four FM-overlaiddigital proposals are given in Table 3.

14.2. EIA test results

The EIA tests were divided into three categories asfollows:

a) subjective quality tests on the source codingsystem, operating in a clear channel (i.e. with notransmission errors);

b) objective digital tests on the overall system per-formance;



AT&T Amati ÁÁÁÁÁÁÁÁÁÁÁÁ

AT&T ÁÁÁÁÁÁÁÁÁÁ

USADR FM 1ÁÁÁÁÁÁÁÁÁÁÁÁ

USADR FM 2


On-channel (IBOC) oradjacent-channel (IBAC) ÁÁÁÁÁÁ

ÁÁÁÁÁÁ

IBOC ÁÁÁÁÁÁÁÁÁÁÁÁ

IBACreserved channelÁÁÁÁÁ

ÁÁÁÁÁ

IBOC ÁÁÁÁÁÁÁÁÁÁÁÁ

IBOC


Audio system ÁÁÁÁÁÁÁÁÁÁÁÁ

Joint stereo PACÁÁÁÁÁÁÁÁÁÁÁÁ

Joint stereo PACÁÁÁÁÁÁÁÁÁÁ

MUSICAMÁÁÁÁÁÁÁÁÁÁÁÁ

MUSICAM


Bit rate range (kbit/s)ÁÁÁÁÁÁÁÁÁÁÁÁ

128 – 160 ÁÁÁÁÁÁÁÁÁÁÁÁ

128 – 160 ÁÁÁÁÁÁÁÁÁÁ

128 – 256ÁÁÁÁÁÁÁÁÁÁÁÁ

128 – 256


Error concealment ÁÁÁÁÁÁÁÁÁÁÁÁ

Yes ÁÁÁÁÁÁÁÁÁÁÁÁ

Yes ÁÁÁÁÁÁÁÁÁÁ

Yes ÁÁÁÁÁÁÁÁÁÁÁÁ

Yes

ÁÁÁÁÁÁÁÁÁUnequal error protection ÁÁÁÁÁÁÁÁÁÁÁÁYes ÁÁÁÁÁYes ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁFEC

ÁÁÁÁÁÁÁÁÁÁÁÁReed-Solomon

ÁÁÁÁÁÁÁÁÁÁÁÁReed-Solomon

ÁÁÁÁÁÁÁÁÁÁHierarchical

ÁÁÁÁÁÁÁÁÁÁÁÁHierarchicalÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁÁTime interleaving depth (ms)





480ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Adaptive equalizationÁÁÁÁÁÁÁÁÁÁÁÁ


YesÁÁÁÁÁÁÁÁÁÁ

YesÁÁÁÁÁÁÁÁÁÁÁÁ

YesÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Modulation ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Discrete multitone,mixture of differential

4- and 8-PSK

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

4-PSK ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Multi carrierÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Direct sequencespread spectrum,8-level 64 pseudo-noise sequences


Demodulation ÁÁÁÁÁÁÁÁÁÁÁÁ

Differential(coherent under study)


Differential ÁÁÁÁÁÁÁÁÁÁ


ÁÁÁÁÁÁÁÁÁSymbol duration (�s)ÁÁÁÁÁÁ

ÁÁÁÁÁÁ250 ÁÁÁÁÁÁ

ÁÁÁÁÁÁ3 ÁÁÁÁÁ

ÁÁÁÁÁ125 ÁÁÁÁÁÁÁÁÁÁÁÁ

500ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Guard interval (�s)ÁÁÁÁÁÁÁÁÁÁÁÁ

14.5 ÁÁÁÁÁÁÁÁÁÁÁÁ

None ÁÁÁÁÁÁÁÁÁÁ



Number of carriers ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

32(18 in single side-

lobe mode)


1 ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

48(8 kbit/s)


1


RF bandwidth of thedigital component (kHz)



200 or 100 ÁÁÁÁÁÁÁÁÁÁ

460with 220 kHz void


125

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

A/D orthogonalityÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Spread spectrum,25 dB below FM

carrier


Spread spectrumÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Spread spectrumÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Frequency slidetechnique


Reference signal, pilotÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

One pilot in eachside lobe


For carrierrecovery


49th carrierÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

None


Total capacity (kbit/s)ÁÁÁÁÁÁÁÁÁÁÁÁ




384


System options ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

One double side lobeor two single side

lobes


100 or 200 kHzbandwidth block



Table 3Main characteristics

(where known) of thefour FM-overlaiddigital proposals

submitted to the EIA.


ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Test


Threshold ofaudibility (TOA)

(dB)


Point offailure (POF)

(dB)ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Test B1 – Gaussian noise (C o/No) ÁÁÁÁÁÁÁÁÁÁÁÁÁÁ


6.2

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Test B2 – CCI (desired/undesired) ÁÁÁÁÁÁÁÁÁÁÁÁÁÁ


5.8


Test B3 – Multipath (C o/No) (note 1) ÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁDoppler 2 km/h, Delay spread 3 �s (Urban, Slow) ÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁ21.8 ÁÁÁÁÁÁ

ÁÁÁÁÁÁ15.1

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁDoppler 60 km/h, Delay spread 3 �s (Urban, Fast) ÁÁÁÁÁÁÁ17.8 ÁÁÁÁÁÁ12.8ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁDoppler 150 km/h, Delay spread 3 �s (Rural, Fast)

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁshort or small impairments (note 2)ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁDoppler 60 km/h, Delay spread 16 �s (Terrain obstructed)



13.5ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Test C2 – CW interference (desired/undesired)ÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

-8.2ÁÁÁÁÁÁÁÁÁÁÁÁ

-7.8ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Test C3 – Flutter (simulated aeroplane) ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

5.2 at 400 km/h,0.0 at 200 km/h0.0 at 100 km/h


not applicable


Test C4 – Weak signal sensitivity (dBm)ÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

-97.5ÁÁÁÁÁÁÁÁÁÁÁÁ

-101.5ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Test C5 – Delay spread/Doppler ÁÁÁÁÁÁÁÁÁÁÁÁÁÁ


ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁBad urban I ÁÁÁÁÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁÁÁÁÁÁunimpared up to 225 km/h


Bad urban II ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

unimpared up to 225 km/h


Typical urban ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

POF level of impairment at 225 km/h

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁHilly terrain ÁÁÁÁÁÁÁÁÁÁÁÁÁPOF level of impairment at 225 km/hÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁRural Area

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁPOF level of impairment at 225 km/hÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁTest C6 – Additional multipath (C o/No)



ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁDoppler 2 km/h, Delay spread 3 �s (Urban, Slow)




Doppler 60 km/h, Delay spread 3 �s (Urban, Fast) ÁÁÁÁÁÁÁÁÁÁÁÁÁÁ


2.8


Doppler 150 km/h, Delay spread 3 �s (Rural, Fast) ÁÁÁÁÁÁÁÁÁÁÁÁÁÁ


6.3


Doppler 60 km/h, Delay spread 16 �s (Terrain obstructed) ÁÁÁÁÁÁÁÁÁÁÁÁÁÁ


3.3


Test D1 – CCI (desired/undesired) ÁÁÁÁÁÁÁÁÁÁÁÁÁÁ


7.2

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁTest D2 – 1st ACI (desired/undesired) ÁÁÁÁÁÁÁ-33.0 ÁÁÁÁÁÁ-34.0ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁTest D3 – 2nd ACI (desired/undesired)

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁnot measurable

ÁÁÁÁÁÁÁÁÁÁÁÁnot measurableÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁTest E1 – CCI + multipath




ÁÁÁÁÁÁÁ22.9 ÁÁÁÁÁÁ

ÁÁÁÁÁÁ17.4




15.4


Doppler 150 km/h, Delay spread 3 �s (Rural, Fast) ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

no CCI added




16.1


Test E2 – 1st ACI + multipath ÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁDoppler 2 km/h, Delay spread 3 �s (Urban, Slow) ÁÁÁÁÁÁÁ-22.3 ÁÁÁÁÁÁ-25.9ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁDoppler 60 km/h, Delay spread 3 �s (Urban, Fast)ÁÁÁÁÁÁÁÁÁÁÁÁÁÁ-25.9

ÁÁÁÁÁÁÁÁÁÁÁÁ-27.9ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁDoppler 150 km/h, Delay spread 3 �s (Rural, Fast)





-24.9 ÁÁÁÁÁÁÁÁÁÁÁÁ

-26.9ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

Test E3 – 2nd ACI + multipath ÁÁÁÁÁÁÁÁÁÁÁÁÁÁ



ÁÁÁÁÁÁÁnot measurable ÁÁÁÁÁÁ

ÁÁÁÁÁÁnot measurable



not measurable ÁÁÁÁÁÁÁÁÁÁÁÁ

not measurable

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁDoppler 150 km/h, Delay spread 3 �s (Rural, Fast) ÁÁÁÁÁÁÁnot measurable ÁÁÁÁÁÁnot measurableÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁDoppler 60 km/h, Delay spread 16 �s (Terrain obstructed)

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁnot measurable

ÁÁÁÁÁÁÁÁÁÁÁÁnot measurableÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁTest J1 – Requisition (s)


not applicableÁÁÁÁÁÁÁÁÁÁÁÁ


Test J2 – Requisition + multipath (s)ÁÁÁÁÁÁÁÁÁÁÁÁÁÁ

not applicableÁÁÁÁÁÁÁÁÁÁÁÁ

1.0

Note 1: There is some debate ongoing in the EIA about the validity of this model, due to the use of a smoothspread spectrum with Doppler amplitude profiles, which is more stringent than real life.

Note 2: In a repeat of the simulated rural, fast multipath condition by the CCETT (France), the TOA correspondedto a little over 130 km/h and the POF corresponded to about 140 km/h. Experiments in Canada indicatethat the real life minimum POF will occur at about 160 km/h.

Table 4Summary results ofthe EIA laboratorytests on the Eureka147 DAB system.


c) objective and subjective compatibility testscarried out to determine the interaction betweenthe digital audio broadcasting system and theanalogue transmission system within the FMband.

The quality assessment results show that theEureka 147 system – using ISO MPEG Layer-IIMusicam at 224 kbit/s – had the highest overallrank and the most consistent ratings across thewhole range of audio material which was used forthe tests. Eureka 147 was the only system thatnever fell below the “perceptible but not annoy-ing” range. Out of nine critical audio passagesthat were evaluated, four were judged to be trans-parent.

The published test results show that, in general,the in-band digital systems may cause intolerablyhigh interference to, and suffer interference from,the analogue services that are overlaid – parti-cularly in a multipath environment. Therefore,those broadcasters who wish to preserve the highbroadcasting standards of their existing FM ser-vices should not opt for an in-band digital solu-tion, given the present stage of its development.

The published test results on the Eureka 147 DABsystem are more favourable. They confirm theconclusions of extensive laboratory and field testsconducted in Europe, Canada, Australia and else-where – that the Eureka system eliminates prob-lems such as FM multipath and signal failure(dropout). It also enables digital radio to coexistwith AM and FM services with no interference.

The results of the EIA laboratory tests on theEureka 147 DAB system are summarized inTable 4.

15. Is Eureka 147 suitable forinternational broadcasting?

In order to cover large zones of the world, interna-tional broadcasters currently use:

a) high-power terrestrial transmitters to radiateAM-modulated signals at LF, MF and HF;

b) sound sub-carriers on 11/12 GHz FSS satellites(with optional local redistribution by terrestrialFM transmitters).

In January 1994, several international broad-casters established a consortium, now called“Digital Radio World-wide”, whose main objec-tive is to improve the technical quality and theavailability of their radio services in the future.

These broadcasters are looking into the possibilityof delivering their programmes via satellite or byhybrid means (i.e. satellite and complementaryterrestrial methods), using the WARC-92 fre-quencies. Another technical possibility would beto use a new narrow-band (nominally 9 kHz)digital system to operate at “AM” frequencies (i.e.below 30 MHz), re-using the existing terrestrialtransmitter infrastructure.

Ideally, the chosen satellite system (designed tocover large areas) will have the same modulation/coding system parameters as the ground-basedsystem (designed to cover regional/nationalterritories), such that the same receiver could beused. An essential requirement for any newsatellite system is that it should be able to providefor mobile and portable reception in all types ofpropagation environments (rural, urban, etc.).

The main concern of international broadcasters iswhether or not the Eureka 147 DAB system isappropriate for the satellite delivery of their pro-grammes.

Although the Eureka 147 DAB system has beendeveloped as a terrestrial system, there is no tech-nical reason why it could not be used for satellitedelivery as well. Many computer simulations haveshown that this assumption may be true, but realexperiments are needed to demonstrate thatsatellite delivery is both a technically viable and aneconomically attractive proposal.

Two such experiments have been conducted re-cently – one in Australia, the other in Mexico. TheAustralian test was carried out using the Optus B3satellite at 1552 MHz. The trial in Mexico, carriedout by the BBC, used the Solidaridad satellite.Both satellites were originally launched to providemobile phone services; they were not specificallydesigned for multicarrier systems such as Eureka147. Even so, the results showed that fixed andportable reception of DAB signals via a satelliteis technically feasible. Due to the low transmittingpower of the test satellites, mobile reception waspossible only under line-of-sight conditions.

A satellite simulation – using a helicopter – isbeing carried out jointly by the ESA, the IRT andthe BBC in Munich, to determine the service-availability performance (i.e. percentage of cover-age) for different elevation angles.

One of the outstanding issues to be clarifiedis whether or not it is possible to up-link fromdifferent feeder-link stations, programmes that


constitute the same multiplex. Studies are beingundertaken within the Eureka 147 Project to deter-mine how on-air multiplexing at RF could be per-formed at the input to the satellite, in a similarmanner to the well-established TDMA12 technolo-gy used with FSS satellites. Preliminary results in-dicate that feeding the satellite from different up-link stations may not be a major technical problem.However, it will be necessary to coordinate be-tween the different feeder-link stations – in termsof time synchronization (approximately only) andpower control – but such coordination is quite nor-mal in any TDMA and FDM system.

Because the Eureka 147 DAB system is a multi-carrier system, some output back-off at the satellitewill be necessary to reduce the amount of inter-modulation. Similar back-off will be necessarywith the alternative FDM systems (such as theWorldSpace system), since multichannel opera-tion already generates multicarriers. Thus, it is fairto assume that there will be no significant differ-ence between the DAB and the FDM systems, interms of the output back-off required at the satel-lite. In the Australian DAB experiment, the trans-ponder operated satisfactorily with an output back-off of 2.2 dB.

Digital System B is a valid candidate to become asecond digital radio system recommended by theITU-R (see Section 8.2.1.). Technically, DigitalSystem B seems to be very similar to the World-Space system, i.e. it uses a single carrier, modu-lated by a relatively high bit-rate signal whichcarries one or more audio programmes and data.Such systems cannot generally overcome multipathproblems unless very sophisticated and expensiveequalization processing is used at the receiver. Sofar, only line-of-sight reception has been demon-strated satisfactorily with this type of system.

International broadcasters are usually interested inlarge coverage areas. Therefore a geostationary(GEO) satellite system could be satisfactory tocover low-latitude areas, such as most parts ofAfrica, Central and South America, India,Indonesia, etc. However, many regions of theworld that wish to be covered are situated inthe northern hemisphere (above 30 – 40 degreeslatitude), including Europe, China and Japan.For such areas, the HEO13 satellite concept –promoted currently by the Archimedes project ofthe European Space Agency – seems to be of inter-est, as it would enable greater penetration to

12. Time division multiple access.

13. highly-inclined elliptical orbit.

mobile receivers in urban areas (due to the highelevation angle of the satellite, and hence lessshadowing of the signals). In practice, a combina-tion of the HEO and GEO concepts may be anattractive solution. The Eureka 147 DAB systemaddresses both GEO and HEO satellite solutions.

It should be pointed out that there are severaltechnical matters associated with the HEO sat-ellite concept which must be considered care-fully, such as hand-over from one satellite to thenext (with the resultant potential for signaldrop-out), zooming of the beam, polarizationrotation and crossing the van Allen belt. Theremay be difficulties also on the regulatory side(sharing of the band, notification procedures,etc.). It is understood that the ESA has beenaddressing the above points to find satisfactorysolutions.

For international broadcasting, all WARC-92bands (i.e. bands located at 1.5, 2.3 and 2.6 GHz)should be considered. Preference should clearlybe given to the 1.5 GHz band for technical andeconomic reasons (the best trade-off between thesize of satellite transmit antenna and its transmitpower). Preliminary studies have shown that, at2.6 GHz, considerably larger transponder outputpower would be required (of the order of fourtimes greater than that required at 1.5 GHz).DAB Transmission Modes II, III or IV are suit-able for use at these frequencies.

16. Which distribution systemfor cable?

The Eureka 147 system can also be used for thedistribution of radio and data services in cablenetworks and SMATV installations. It may beparticularly useful in cases where the quality ofthe cable network is poor, due to standing-wavereflections (i.e. signal echoes on the network).A standard DAB receiver could be used; apartfrom frequency conversion, no transcoding orremodulation would be necessary in this appli-cation.

However, when the primary objective is spectrumefficiency, the service provider will probably wishto use the DVB cable system [2] which is based on64-QAM. In an 8-MHz cable channel, DAB canaccommodate 24 stereophonic channels with adata rate of 256 kbit/s, each using the lowestprotection level (i.e. 3/4). A 64-QAM system, onthe other hand, would allow for some 150 channelsof the same audio quality.


17. Broadcasters’ expectations

The BBC has produced a document [20] whichcontains its expectations of first-generation con-sumer DAB receivers. The document is intendedto assist receiver manufacturers in the productionof attractive consumer sets which will respond ad-equately to the BBC’s DAB signals and which willsatisfy the UK public following the launch of thefirst BBC DAB services in September 1995. Thedocument is broadly in line with an earlier EBUdocument [21] which published the more generalrequirements of first-generation DAB receivers.

The first consumer receivers are expected to be foruse in vehicles and in home hi-fi units. Portable,personal and other types of receiver are expectedto appear on the market somewhat later. If DABis to achieve rapid acceptance and success, the de-velopment of all receiver types must be promotedin the early years of DAB service.

The BBC plans to include Service Information (SI)from the start, as well as the Multiplex Configura-tion Information (MCI). A list of the SI featureswhich were expected to be broadcast at the start ofthe BBC DAB service, and in later years, is givenin Table 5.

18. DAB as a multimedia carrier

Within the Eureka 147 Project, further develop-ments are underway to study the use of the Eureka147 System as a multimedia and data broadcastingsystem. This study is aimed at expanding thefuture use of the Eureka 147 DAB system beyondthe provision of excellent sound reception inadverse mobile and portable environments. Inaddition to the conventional audio services, thesystem is opening up many new opportunities tocarry a number of non-audio services, such as text,still pictures, moving images, etc.

The multiplex of the Eureka 147 system has beendesigned to carry a large number of digital serviceswith a total bit rate of up to 1.7 Mbit/s, organizedin up to 64 stream- or packet-mode subchannels.Four different data transport mechanisms havebeen defined in the DAB standard:

- Programme Associated Data (PAD)

- Fast Information Channel (FIC)

- Stream Mode (SM)

- Packet Mode (PM)

The choice of transport mechanism depends onthe kind of data that it is necessary to transport.For example, the Programme Associated Data issuitable for services which bear a strong relation-ship to the audio signal. Since this data is takenfrom the audio frame, there is a trade-off betweenthe intrinsic audio quality and the PAD datacapacity.

The FIC Channel was originally intended to carryinformation on the organization of the DAB multi-plex. Nevertheless, the FIC can carry a limitedamount of additional information, such as pagingand emergency warning messages. Dedicated (orspecial-purpose) receivers which only decode theFIC part of the multiplex may be significantly lesscomplex than general-purpose DAB receivers.

In Stream Mode, a subchannel is assigned to asingle data service, providing a fixed data rate(in multiples of 8 kbit/s) with specific errorcorrection.

In Packet Mode, a number of services may sharethe same subchannel. Packet headers contain aservice address which allows the receiver torestore the original data. The PM is a convenientway to carry asynchronous services (which usevariable data rates).

Examples of DAB data services currently beingimplemented are given below. These services maybe presented either in the form of textual infor-mation (shown, for example, on a simple receiverdisplay of, typically, between 8 and 128 charac-ters), still pictures or even video images.

– Programme-associated services such as currentsong title, interpreter and performer, lyrics,news headlines, CD covers, etc.;

– News including events, traffic messages,weather, sport, stock market, travel and touristinformation;

– Traffic navigation by means of transmitted digi-tized roadmaps, combined with positionalinformation provided via the GPS system.

– Advertisements and sales including salescatalogues, purchase offers, etc.;

– Entertainment including games and non-commercial bulletin boards;

– Closed user group services such as bankinginformation, electronic newspapers, fax print-outs and remote teaching.


DAB application BBCtimescale

BBC comments

Multiplex Configuration Information (MCI) Sept 1995 Essential

Multiplex Reconfiguration Sept 1995 Essential

Service text labels Sept 1995 16- or 8-character formats

Ensemble text label Sept 1995 16- or 8-character formats

Time and date Sept 1995 Resolution in minutes

Dynamic range control 1996 BBC Radios 3 and 4 only

Programme label 1996

Programme type: basic dynamic Sept 1995 Source from RDS (international table of codes only)

Programme type: dynamic + 1996 Source from RDS (international table of codes)+ preview

Programme type: dynamic ++ �1997 Full coarse code range + agreed fine codes

Programme type: dynamic +++ �1997 Extend to include programme types in otherensembles, when they have commenced

Programme type: dynamic ++++ �1997 Re-definable codes added

Service following to FM/AM(alternative service sources)

1996 Regions to be defined and TII database to be estab-lished

Service following to other ensembles(alternative service sources)

�1997 Required when further ensembles are available andservices are linked; need to define regions and toestablish TII database

Programme delivery control Sept 1995 Source from RDS PIN

Programme language identification Sept 1995 Statically set to “English”; may be set for dynamicoperation later

Announcements within ensemble 1996 Use eight types only; there is a need to define clusters,regions and labels and to establish the TII database

Announcements from FM services 1996 Traffic only (sourced from RDS)

Announcements from other ensembles �1997 Required when the BBC has access to otherensembles

Public service warning 1996 Floods, bad weather, etc.

Local broadcasting �1997 Required when the BBC has access to otherensembles

Extended text labels �1997 Depends on developments in the recording industryand suitability for broadcasters’ requirements

Coded traffic messages �1997 Packet mode required?

National security warning �1997 Not for public access

In-house signalling 1996 BBC internal use

Programme service directory �1997 Gives the receiver information about all BBC serviceswhen there is more than one ensemble

Location finding No plans

Assistance to the hard of hearing No plans

Music / Speech No plans

Copyright No plans Unless required by international bodies

Conditional access �1997

Data down-loading No plans

Paging service No plans

Satellite information No plans

Table 5BBC timescale for theimplementation ofspecific DABapplications.


The DAB Standard offers two modes for texttransmission: Dynamic Label and InterractiveText Transmission (ITTS). The former mode issimilar to the Radio Text feature of the RadioData System (RDS) on the FM band. ITTS is amore sophisticated text transmission system. Itallows for menu-driven operation and can alsobe used to transmit text at the rate a broadcasterprescribes. It can process several streams oftextual information simultaneously to convey,for example, the same information in severallanguages or to transmit a programme scheduleat the same time as giving details of the pro-gramme currently on-air.

Ideally, multimedia services should be fully inter-active, in which case the consumer can communi-cate with the service provider’s database. Sincebroadcasting services are one-way only, the returnchannel could be provided by GSM telephone (inthe case of mobile DAB receivers) or via a tele-phone line (in the case of a fixed receiver). Never-theless, a semi-interactive mode is also possible.In this instance, information is downloaded by theservice provider to the user’s data terminal andstored there as a database. All interactivity is thenhandled within the user’s data terminal, but thedatabase contents have to be updated regularly bythe data service provider. The storage capacity ofthe user’s terminal is a trade-off between the ser-vice transmission rate, the repetition rate and thecost of the memory.

A key factor for the success of DAB will be itsability to address each receiver individually. Thiswill allow service providers to customize the“bouquet” of services provided to each user, andeven to identify the user in an interactive trans-action. This feature has some far-reaching im-plications, particularly for privately-funded radio.

Studies are continuing on the suitable presentationof DAB data services. Currently, data servicesspecified in the ETSI Standard have a text-basedpresentation. In order to improve the man-machine interface, the Eureka 147 System will beenhanced to support a graphical user interface,such as Microsoft Windows. This will be ofimportance for screen-based services which seemto be more relevant for stationary and portablereceivers. For mobile receivers, synthesizedspeech-based interfaces are a better alternative, asthey would be less distracting to drivers.

For the user’s data terminal, a unified transmissionprotocol will be very helpful, as no distinctionbetween different transport mechanisms would be

necessary. A software-based language for object-oriented page description is being developed todefine a communication and a presentation layer.Such a unified protocol for the multimedia trans-port mechanism could be used not only withDAB services, but also in other communicationssystems.

Currently, within the Eureka 147 Project, a stan-dard receiver data interface is being specified totransfer the data carried within an ensemble, fromthe receiver to any external devices such as a PC,tape recorder or conditional access decoder (seeSection 8.3.).

A demonstration of both the audio and the multi-media usage of the Eureka 147 system was givenduring August 1995, at the IFA fair in Berlin.

19. Programming

The technology of DAB is a means of deliveringaudio programmes and data; it is not an objectivein itself. Hence, the debate must eventually (if notsoon) move away from the technical advantages ofDAB to the programming issues which willactually drive this technology into the homes andcars of radio listeners.

People will buy receivers only if they can accessinteresting, entertaining and attractive pro-grammes. Crisp digital sound is of course a goodthing, but it is certainly not sufficient to persuadepeople to pay for it. Therefore, the content and thepresentation of the audio, video, text and datainformation which is to be transmitted is of greatimportance. So far, insufficient new program-ming ideas have been put forward but it is hopedthat the Eurodab Forum will help to generatesome ideas on this matter.

20. Manufacturers

In order to receive DAB services, consumers willneed to buy a new kind of receiver. The consumerDAB receivers will also contain FM and AM cir-cuits which, initially, will be analogue. However,it will not be long before the AM and FM circuitsin a DAB receiver become digital. These all-digital AM/FM/DAB receivers will be based onadvanced computer technology, which will allowthe downloading of large quantities of informationto program the radio set and its associated equip-ment (digital cassette recorders, MiniDisc record-ers, PCs, etc.).


At the recent IFA fair in Berlin, six manufacturers(Alpine, Bosch, Grundig, Kenwood, Philips andSony) displayed their current DAB receivers. Infact, they look more like semi-professional equip-ment; the DAB part is in a separate box, mountedin the boot with a link to an FM/RDS receiver inthe dashboard. These first-generation car receiv-ers are not generally available yet; they can onlybe purchased on special order and in limitedquantities for evaluation purposes. As shown inFigure 2, the first mass-produced DAB car radiosare not expected until 1997; the first portableDAB receivers are projected for 1999.

The industry has been carrying out a lot of researchand development on further applications of theDAB system, including:

– data-only receivers;

– picture radios and advanced teletext full bit-stream video decoders;

– navigation systems;

– differential GPS;

– traffic information systems;

– Traffic Message Control (TMC);

– real time packet-mode multiplexers /demultiplexers;

– fax;

– videotext;

– audio in conjunction with radiotext (dynamiclabels);

– electronic newspaper publishing, including textand pictures in packet mode;

– high-capacity storage using MiniDisc.

21. Conclusions

The Eureka 147 DAB system – now an ETSIEuropean Standard and an ITU worldwide Stan-dard – has all the ingredients to be converted froma brilliant technological achievement into a verysuccessful product in the marketplace.

The Eureka system has great potential for manyreasons: governments are facing the hard task ofsharing out the finite radio spectrum between amass of conflicting interests and they welcomeDAB as a highly spectrum-efficient system;broadcasters see the opportunity to offer moreservices of better quality and presentation;manufacturers welcome the opportunity to selllarge quantities of DAB receivers andassociated equipment, and network operatorsare keen to build the new distribution andtransmitter networks that are required for DABterrestrial services. Not least, the listener wel-comes a new technology which offers morechoice and higher technical quality, as well as avery robust signal when listening in a vehicle oron a portable set.

A new frequency allotment plan at VHF and inL-Band has been agreed for Europe. It providessufficient frequencies for the start of terrestrialDAB services and, at the same time, leaves theexisting FM services in Band II untouched, in theshort term.

Official DAB services started during Septemberin both the UK and in Sweden and this shouldencourage manufacturers to bring their DABreceiver products to the marketplace as soon aspossible.

The broadcasters, together with manufacturersand network providers, are continuing theircooperation to investigate how DAB can be usedoptimally for new applications which will beattractive for all listeners. The recently-formedEuroDab Forum will be instrumental in pursuingthose objectives.

Prophecies of the death of sound radio have provedunfounded. The radio is more alive today than anyother medium!

50

40

30

20

10

0

Pow

er c

onsu

mpt

ion

’89 ’90 ’91 ’92 ’93 ’94 ’95 ’96 ’97 ’98 ’99 2000

W

Year

2nd-generationprototype

3rd-generationprototype

4th-generationprototype

1st carproduct

2nd carproduct

1stportable

Figure 2Timescale for theavailability of variousDAB receiverstogether with theirpower consumption.


Acknowledgements

The author wishes to thank sincerely his manycolleagues from the EBU, the Eureka 147 Con-sortium and the EuroDab Forum for their valuablecontributions to the information given in thisarticle. The Directors of the above organizationsare also gratefully acknowledged for giving per-mission to publish this information here.

Bibliography

[1] ETS 300 421: Digital broadcasting systemsfor television sound and data services;framing structure, channel coding andmodulation for 11/12 GHz satellite ser-vices.ETSI, December 1994.

[2] ETS 300 429: Digital broadcasting systemsfor television sound and data services;framing structure, channel coding andmodulation for cable systems.ETSI, December 1994.

[3] ETS 300 473: Digital broadcasting systemsfor television sound and data services;Satellite Master Antenna Television(SMATV) distribution systems.ETSI, May 1995.

[4] ETS 300 401: Radio broadcasting sys-tems; Digital Audio Broadcasting (DAB) tomobile, portable and fixed receivers.ETSI, February 1995.

[5] ITU-R Report 955-2: Satellite sound broad-casting to vehicular, portable and fixedreceivers in the range 500 – 3000 MHz.ITU-R document 10-11S/55, July 1992.

[6] ITU-R Report 1203: Digital sound broad-casting to vehicular, portable and fixedreceivers using terrestrial transmitters inthe VHF/UHF bands.ITU-R document 10B/TEMP/54, November1993.

[7] ITU-R Recommendation BS.774-1: Servicerequirements for digital sound broadcast-ing to vehicular, portable and fixed receiv-ers using terrestrial transmitters in theVHF/UHF bands .

[8] ITU-R Recommendation BO.789-1: Servicerequirements for digital sound broadcast-ing to vehicular, portable and fixed receiv-ers for BSS (sound) in the frequency range500 – 3000 MHz.

[9] ITU-R Draft Recommendation BS.1114:Systems for terrestrial digital soundbroadcasting to vehicular, portable andfixed receivers in the frequency range30 – 3000 MHz. June 1995.

[10] ITU-R Draft Recommendation BO.1130:Systems for digital sound broadcastingto vehicular, portable and fixed receiversfor BSS (sound) bands in the frequencyrange 1400 – 2700 MHz. June 1995.

[11] ITU-R Special Publication: Terrestrial andSatellite Digital Sound Broadcasting tovehicular, portable and fixed receivers inthe VHF/UHF bands.

[12] Draft EACEM Technical Report No. 09:Characteristics of DAB Receivers.EACEM, May 1995.

[13] EBU Recommendation R79-1994: Recom-mended system for digital sound broad-casting to mobile, portable and fixedreceivers in the appropriate frequencybands in the range 30 MHz to 3 GHz.

[14] Waters, G.T.: The new role and structureof the EBU.EBU Technical Review No. 264 (Summer1995).

[15] Guidelines for implementation andoperation (Volumes I, II and III).Prepared by joint Eureka 147 DAB / EBUTask Force on system standardization, Issue2.1, December 1994.

[16] Definition of the Ensemble TransportInterface.EBU doc BPN 002, Issue 4.4, March 1995.

[17] Hunt, K.J.: Personal reflections on theCEPT T-DAB Planning Conference:Wiesbaden, 3 - 21 July 1995.EBU Technical Review No. 265 (Autumn1995).

[18] Technical bases for T-DAB Services Net-work Planning and Compatibility withexisting Broadcasting Services.EBU Technical Document, June 1995.

[19] Report on Digital Audio Radio LaboratoryTests; Transmission Quality, Failure char-acterization and Analog Compatibility.EIA Consumer Electronics Group, August1995.

[20] BBC expectations of first generationconsumer DAB receivers.BBC DAB Project Office, April 1995.

[21] EBU expectations for first-generationproduction DAB receivers.EBU Technical Statement D74-1992,December 1992.

Digital Audio Broadcasting – radio now and for the future · 2016-09-05 · 2 EBU Technical Review Autumn 1995 Kozamernik Digital Audio Broadcasting – radio now and for the future

Documents