DAB Basics

     Digital audio broadcasting may be seen as the third stage in the use of the electromagnetic spectrum to transmit radio broadcasting services after analog AM and FM, both of which are prone to interference. In AM's case this is caused by static and other unwanted signals, by sky waves reflected from the ionosphere, and by other stations on the same or nearby frequencies. FM's main problems stem from unwanted reflections from high-rise buildings and other objects that cause what engineers term multipath distortion.

     There are probably about 2.5 billion receivers with AM or medium wave reception capability in the world. Despite the expansion of FM, AM remains the most widely available means of reception. Both national and international radio broadcasters continue to rely on AM for much of their transmission requirements. The capacity of AM's medium waves to reach beyond horizons and thus much further than FM transmitters makes it essential and irreplaceable. For many countries, DAB is too expensive because a complex and extensive transmitter network is required.

     DAB represents a major break with this analog technology. Like all digital systems, it converts the original material into streams of "zeroes" and "ones", which are then reconverted to recreate the original information. DAB, and specifically the EUREKA 147 system, differs from earlier digital systems in being capable of transmitting over a number of different "platforms," including both terrestrial (land) and satellite (delivering services either separately or jointly) and over a large section of the electromagnetic spectrum: from 30 MHz to 3 GHz for mobile reception, and higher for fixed reception.

     DAB can be accomplished in any of three ways: (1) in-band, on-channel (IBOC) or in-band, adjacent channel (IBAC) using existing AM and FM terrestrial frequencies (actually blank spaces between frequencies); (2.) . terrestrially over another broadcast band (S-band in the United States and L-band elsewhere); and (3) by satellite digital audio radio services (SOARS), which bypasses terrestrial broadcasters by sending signals directly to consumers. (See separate entry, Digital Satellite Radio.)

     The main advantages of DAB, compared with analog radio broadcasting, are many. First, DAB produces a much closer (technically accurate) replication of the original sound produced by the receiver, together with easier/automatic tuning than analog techniques.

Second, DAB is more efficient in its use of the radio spectrum and has a lower power requirement. Using the "multiplex" system, a number of radio transmitters carrying multiple signals can "overlap" on the same frequency-if broadcasting the same material. A "single frequency network" means that only one frequency needs to be used to cover a wide area­ including a whole country. This compares well with the amount of spectrum needed for analog services. The overall digital signal is produced by 1,536 "carrier frequencies" that are distributed over a 1.5-megahertz band. The majority of these carriers are noise-free, and this, coupled with error-correction techniques, means there is no interference to any of the services.

     Third, there is at least the potential for many more services in the same spectrum, compared with analog transmissions. This is because the total digital "bit rate" available on the single frequency-r.2 megabits-can be "sliced" in an almost limitless number of configurations, so more services can be "squeezed" into the same part of the spectrum. However, there is a widely accepted minimum bit rate per second (bp/s) thought to be necessary to provide acceptable quality of either mono or stereo transmissions, and a lower rate to be used for text, graphics, and pictures without causing distortion or interference.

     Finally, material other than sound can also be transmitted with the "radio" signal, because many other types of media can also be converted and then reconverted in roughly the same way. Thus digital methods can transform sound broadcasting into a multimedia system.

     The main disadvantages of digital radio broadcasting are the following: first, a variety of different systems are being developed (unlike AM or FM, there is as yet no agreement on a worldwide standard); second, one transmitter serving a number of different radio services on one multiplex means that less well established, independent organizations are likely to be excluded; finally, listeners will have to buy new radio receivers that are at least initially significantly more expensive than those for analog systems. Indeed, the total consumer expense for this technology will be vastly larger than what stations have to pay out.

EUREKA 147

      The earliest digital radio system to reach adoption was the European EUREKA standard. The main reason for its development was to provide a new, distinct outlet for the European consumer electronics industry, which had been overshadowed by those in Japan and other "tiger" economies of the Far East. The name "EUREKA 147" derives simply from the prosaic fact that it was the 147th system to be developed under the umbrella of the EUREKA project, which was launched by 17 countries and the European Commission in 1985.

     Work on a possible DAB system began in 1981 at a research institute, the lnstitut  für Rundfunktechnik. The original base of the EUREKA 147 project and its main participant was a (West) German research institute-the DLR Projekttrae­ ger lnformationstechnik in Cologne. Both Germany and France contributed 36 percent of the costs of the project, the United Kingdom just 6 percent.

     By 2003 the World DAB Forum indicated that some countries around the world were operating a DAB system. using the EUREKA standard. Outside Europe, the system is particularly well developed in former British colonies, notably Singapore, Hong Kong, Australia, Canada, and India. China is also operating the system, and thus the two most populous countries in the world have committed themselves to the "European" standard. One of the main advantages claimed for EUREKA is that it can be transmitted on all the main broadcasting platforms, terrestrial and satellite-the latter clearly important for covering large and sparsely populated areas, such as Canada and Australia, and over a large number of frequency bands.

Digital Radio Mondiale

     Although EUREKA is undoubtedly the most developed and operationally established DAB system, several others are either in operation or are close to being so. A system developed by a private United States-based company, WorldSpace, designed for international broadcasting to developing countries by satellites, became fully operational in 1999, but the system requires new transmitters and, most significantly, new and completely different radio receivers. There is also a system for transmitting shortwaves in digital form, called Telekom-TELEFUNKEN­ Multicast, which was developed in Germany. These systems can be transmitted alongside current analog services on the same parts of the radio spectrum and may be converted by receivers requiring relatively little modification.

     Another system comes from a consortium called Digital· Radio Mondiale (DRM) and is designed primarily to complement AM broadcasting; this system was originally also developed as part of the EUREKA projects. DRM is a worldwide consortium of broadcasters, receiver and transmitter manufacturers, transmission companies, regional broadcasting unions, and research institutes. It is coordinating the development, standardization, and market roll-out of the system from 2003 onward. While the original drive came mainly from international shortwave broadcasters, the consortium now involves both domestic and international radio companies. Beginning in 1998, work proceeded very quickly and system development was completed during early 2001. In April 2001 the International Telecommunication Union (ITU) approved the DRM system for analog AM broadcasting. The DRM system overcomes the many defects of analog broadcasting-especially its often poor sound quality, fading, and interference. It is capable of greatly increasing the audio and reception quality, making it similar to good FM.

     As with other digital technologies like DAB and the World­ Space system, provision of supplemental program information or other information independent from the program is possible. It will also be possible to manufacture receivers in such a way that there will be no more need to search for alternative frequencies. The name of a station would be sufficient to receive the wanted program. The receiver will automatically retune and change the frequency to the best one for the respective station chosen. This will be especially important for the many stations in Africa, Europe, and Asia that operate on several different AM frequencies.

     DRM was established as a worldwide consortium to develop a single system for digital broadcasting in the frequency bands below 30 MHz. The formal inauguration of the group took place in Guangzhou, China, in March 1998. It is a not-for-profit organization registered in Switzerland with a single goal: to bring affordable, digital sound and services to the world radio market. By mid-2001, DRM had 69 members from 27 different countries. A project office is located in Geneva.

     A second proposal, from the United States, was also designed specifically for medium wave broadcasting. Developed by USA Digital Radio (which later merged with Lucent to form iBiquity), it takes a different approach from DRM, requiring 30 kHz high frequency channels. DRM and USA Digital Radio were cooperating so that listeners could receive both systems with the same receiver. However, since the merger with Lucent this cooperation has come to a halt, and it will be up to the receiver manufacturers to decide which system will be implemented. Only the DRM system fulfils all the ITU requirements for long-, medium- and shortwave, and will therefore be the replacement of the analog broadcasting system below 30 MHz in the future.

DAB in the United Kingdom

      In the United Kingdom, the development of DAB using the EUREKA 147 standard has been slow-certainly in the commercial sector. The BBC began full test transmissions in September 1995. Within the frequency spectrum allocated by the U.K. government to DAB (217.5-230 MHz), there is room for seven frequency blocks; two of these have been allocated for national radio coverage, one for Independent National Radio services and one for BBC national services. The remaining five multiplexes have been allocated for local/regional radio services, to be awarded by the Radio Authority (which regulates and licenses U.K. commercial radio).

     The national commercial multiplex, run by a consortium called Digital One, carried up to ten services-simulcasts of the three national commercial stations, plus a classic rock station, a spoken word service featuring readings of books and plays, and a middle-of-the-road music station. The roll-out of Digital One's network of transmitters happened faster than those for the BBC's national DAB multiplex-quickly reaching 85 % of the U.K. population. However, there were setbacks, as the suppliers of a radio version of the Independent Television News (ITN) rolling news service, and of finance and business channel Bloomberg, pulled out of the multiplex, which meant that by the end of 2002 two channels were broadcasting nothing more interesting than "tone." In addition to the national multiplexes, over 4 5 licences for local and regional services were expected to be issued by the beginning of 2004-each offering a "bouquet" of services, including simulcasts of FM and AM services. Of the "digital only" services, typically about three of these would be stations broadcasting in other parts of the country as well as, usually, two or three which have been created specifically for the DAB system in that area. In all, over 300 digital services were being offered on U.K. DAB transmitters.

     There was a huge incentive for the commercial services to pay for their analogue services to be available on the DAB "platform": if they did so, the 1996 Broadcasting Act compelled the sector's licensing body and regulator, the Radio Authority, to automatically renew their analogue licenses, which would otherwise be re-advertised every eight years. A Communications Bill-scheduled to become law by fall 2003-extended a further renewal period to 12 years, meaning that those investing in DAB transmission would have their analogue licenses on a 20 year lease. With FM licenses at a premium and otherwise liable to intense competition, the cost of simulcasting on DAB seemed a relatively small price to pay for the knowledge that their main services were secure.

     An amendment to the 1996 Act of Parliament allowed the commercial operators to double the percentage of the multiplex "cake" used for non-audio services. This opened up increased possibilities for the development of commercial text­-based services. Unlike the internet, the number of consumers downloading such services on DAB receivers is unlimited and does not increase the cost to the supplier, so this seemed likely to be an attractive additional source of revenue for the commercial operators.

     Although no such financial incentive was on offer to the BBC, the Corporation's enthusiasm and commitment to DAB remained undimmed-although some senior managers were on record stating that, with hindsight, they had probably invested in it too quickly and too heavily. By the end of 2002 the BBC's national multiplex was offering simulcasts of its five national networks; plus the BBC World Service; an extra sports channel; a new music channel-6 Music-featuring rock sessions from the BBC's archives and pitched at the "young middle aged" audience; BBC 7 playing archive comedy and drama programs plus original, new programming, for children; and the BBC Asian Network. All of these include scrolling text showing program information and news and sports headlines as appropriate.

     Despite the proliferation of program services, however, the take-up of digital radio receivers was slow and patchy, with industry estimates that only about 60,000 DAB sets had been sold by the summer of 2002. The main reason for the apparently unenthusiastic response from the listening public was price-manufacturers and campaigners for DAB were caught in a classic economic dilemma: where only a relatively few consumers were prepared to pay several hundred pounds for a DAB receiver, large-scale, and therefore cheaper, production of the electronic chips and sets required mass sales. The early models for home use were designed for the high end of the consumer hi-fi market and therefore appealed to a relatively small number of enthusiasts with high disposable incomes.

     The introduction of the first sub-fiio portable (designed only for plug-in use) receiver in the middle of that year led to a more than doubling of DAB radio purchases in the crucial run­ up to Christmas. Indeed, consumer demand far outstripped supply with customers being put on waiting lists. At least one manufacturer brought out a portable combined DAB radio and CD player, and DAB radios available for automobiles expanded and became cheaper, lighter, and easier to fit.

     By the spring of 2003 at least two small, battery-powered sets using third generation DAB chips were on the market. The integration of DAB receivers into cell-phones seemed imminent (several models already incorporated an FM receiver, with 2 percent of adults listening to radio via their cell-phone) and key manufacturers were promoting DAB receivers. Crucially, the BBC began to heavily promote its DAB (only) services, with program listings included in the best-selling magazine the Radio Times-published by the Corporation's commercial arm-and a major on-air promotion on both radio and TV in the summer of 2003. Continued support for DAB from national government was made explicit when the Secretary of State for Culture, Media and Sport (at a meeting of the Social Market Foundation in March 2003) praised the BBC and commercial sectors for putting aside their normal rivalries for a common development and promotion of DAB and said this had helped ensure that digital radio was not only "a great British success story" but that the U.K. was the most advanced country in Europe in its development. (In fact, Sweden could probably claim that title, certainly in terms of population coverage.) The Minister also opened the possibility of a date for switching off analogue radio transmitters.

     One rather unexpected phenomenon was a considerable increase in radio being consumed through television. All the digital TV platforms-terrestrial, satellite, and (most) cable­ allowed a range of radio services, usually including all the national DAB services. Most significant of these was probably the re-launched national TV digital terrestrial service-with financial backing by the BBC-which allowed consumers to watch and listen to a range of free-to-air services received through the "normal" TV aerial. This meant that hundreds of thousands of consumers, who were reluctant to pay for satellite dishes and subscription fees and were certainly unlikely to be "early adopters" of DAB radio sets, were now exposed to the DAB stations. By the end of 2002, 16 percent of U.K. adults-nearly 8 million-were listening to radio services via their TV.

     All the national DAB services-BBC and commercial-were "live streamed" on the internet. Although reliable figures for individual services were hard to come by, it was estimated that around 12 percent of adults listened to "streaming" radio via the internet in a typical week, although much of this was to services originally created for analogue radio. Several DAB receivers were developed for plugging into computers. Indeed, some of the DAB non-audio services were developed specifically for this sort of integrated use. As well as seeing the scrolling text and program information available on "normal" DAB radios, a range of other information and web links were also presented on screen.

     The link with the internet and the increased possibilities of interactivity between broadcaster and listener, as well as the integration between the different media, seemed likely to be a trend that was both increasing and intriguing. In early 2003 the MXR consortium-a joint venture between Chrysali Radio, Capital Radio, Jazz FM, and the Guardian Media Group­ announced an agreement with U.S.-based technology firm Command Audio to launch "on-demand audio." The facility will allow listeners to their DAB multiplexes to listen to local news, sports, travel, and business bulletins whenever they want. The ability for individual DAB listeners to "rewind," to "time-shift" programming elements, had for some time been one of the promised benefits of the technology.

     All of this raised fascinating questions about the nature of radio as a medium and its relationship to the audience. Broadcasters had to consider the different ways that DAB was being consumed (through DAB radio receivers, TV sets, online, and over cell-phones), as well as the implications for this in their programming and marketing.

     The United Kingdom's 1996 Broadcasting Act and the Radio Authority's interpretation of it has resulted in the geographical and population areas of local digital licences broadly matching the existing coverage areas of analog broadcasters. The effect of this is to greatly restrict the flexibility of the system: as with analog broadcasts, separate services can­ not be broadcast on the same frequency, and there has to be sufficient distance between transmitters broadcasting different material on the same frequency to avoid mutual interference. At the local level, DAB is no more efficient than analog in the use of the frequency spectrum. This inefficiency and the fact that having at least two frequencies to carry national networks means that most areas will (at least until 2007, when other frequencies may be available) have a maximum of two "local" multiplexes.

     A unique feature of the transmission arrangements of DAB in the United Kingdom is that BBC local/regional analog services have a "must carry" requirement on commercial multiplexes, but there is no automatic right of access for local/regional ana­ log commercial stations, nor is there any limit to the number of services also broadcast-simulcasted---on analog.

     A study of the license applications for commercial multiplexes reveals how the perceived "early adopters" market-the people who are most likely to be the first to invest in digital radio receivers-is linked with particular types of programming designed to appeal to them. One of the key demographic groups is clearly affluent males aged 25 to 45.

     It also seems clear that EUREKA 147 is, to some extent, "technologically deterministic" in that it "naturally" favors large rather than small geographic areas of broadcasting, even though there is no overriding technical reason why national, and especially regional, services should be favored over local. The pattern adopted in the United Kingdom greatly favors large area services and, almost inevitably, large commercial interests.

DAB in Scandinavia

     The development of EUREKA 147 DAB is on a fast track in the Nordic countries. Leaping into DAB before there is a robust popular market eager to receive digital signals is an unattractive commercial proposition. Thus, government initiatives are driving the transformation process, and Nordic public broadcasting companies bear much of the responsibility for building the DAB infrastructure necessary to expand this market.

     Three factors underlie rapid Scandinavian DAB development. First, DAB significantly increases the possibilities for transmitting radio signals. There is no longer room for any development of AM or FM analog signals given the rapid growth of private and public channels since the mid-198os (the bandwidth required for one FM channel is sufficient for six DAB channels). Second, DAB significantly increases production efficiency in radio programming. Public service companies in northern Europe are adding new radio channels to compete more effectively with the private sector via audience segmentation. The digital platform offers synergistic possibilities at a higher speed and efficiency. "Versioning" content, a process whereby the same "raw content" can be reconfigured in a variety of ways appropriate to the program format and audience interests of respective channels, is increasingly important in this context. Finally, DAB significantly increases integration possibilities across and within media industries. DAB is the only viable opportunity for radio broadcasting to maintain and advance its position in an increasingly competitive market place.

     Although private broadcasting companies in Scandinavia have not yet been deeply involved with DAB development, that will soon change. The cost for a car DAB receiver was nearly $1,000 at the turn of the century. Seven manufacturers are competing in the DAB receiver retail market, and prices are dropping. Four of the best-known companies are Clarion, Sony, Pioneer, and Grundig. It is expected that the cost of a combined receiver and boot box will decline by half in the early 2000s. As signal coverage increases and receiver purchase prices decrease, the open market for DAB broadcasting will surge.

     The transition to digital systems challenges the culture of public service radio. As the number of channels multiply and the scope of the private sector involvement increases, it is increasingly difficult for any public service company to provide a comprehensive and competitive range of radio program services. Achieving that nonetheless remains the heart of democratic principles that characterize and legitimate the approach. Despite the certainty of DAB development in the Nordic countries, the digital future is laden with risks. A key factor hinges on when FM signals will be eliminated. That is at least a decade away from happening, although the pace will ultimately depend on consumer receiver purchasing decisions. Still, DAB developments are taking place more rapidly in the Nordic region than in the United States because there are fewer vested interests fighting the transition, stronger government involvement, and a common EUREKA 147 standard. Further, there are experienced and capable public broadcasting compa­nies managing much of the risk as a tax-supported initiative.

DAB in the United States: IBOC

     The United States has taken a different approach to digital radio. On 1 August 1990, the Federal Communications Commission (FCC) initiated a Notice of Inquiry into DAB development and implementation. The FCC and broadcasting business became interested in DAB after learning that Europe was developing its EUREKA 147 system. By 1991 the American radio industry responded with USA Digital Radio (USADR), a partnership of CBS, Westinghouse Electric Corporation, and Gannett to develop an in-band, on-channel (IBOC) system of DAB to eventually replace AM and FM. USADR preferred IBOC over other methods because it allowed stations to con­tinue existing analog AM and FM service as they developed new digital signals that eliminate multipath and noise and reduce interference.

     IBOC DAB has been called the "Holy Grail solution" because broadcasters can convert from analog to digital without service disruption and with low start-up costs while maintaining their heavily promoted dial positions. Initially the National Association of Broadcasters (NAB) supported DAB implementation using the EUREKA 147 system on L-band (500 to 1500 MHz), which it believed would give AM and FM equal footing. Incensed broadcasters caused NAB to change their position and support IBOC.

     On 26 August 1992, USADR successfully delivered IBOC DAB on the expanded AM band at 1660 kHz in Cincinnati. At the September NAB radio show in New Orleans, USADR demonstrated its system using WNOE-AM and NPR affiliate WWNO-FM. In 1993 NAB's DAB task force officially endorsed IBOC because it believed the FCC would never allocate alternative additional spectrum for DAB. The Electronic Industries Association (EIA), which had held that no system should be selected until all types were tested, struck a compromise with the NAB, agreeing that other systems would not be considered unless IBOC systems were shown not to meet terrestrial DAB requirements.

     While much of the world appears convinced L-band is the best DAB spectrum, the FCC supported use of the S-band (2310 to 2360 MHz), in part because of the difficulty in shifting existing L-band spectrum users in the United States. Most non-FCC experts agreed S-band will be more expensive and less effective than L-band. As a result of the S-band decision, U.S. DAB will be IBOC, causing global incompatibility. At NAB's 1993 Las Vegas convention, USADR introduced broadcasters to its IBOC system, demonstrating that its !BOC system was more fully developed than any system other than EUREKA 147.

     USADR and Lucent Digital Radio (LDR) agreed to work together on IBOC in May 1997, making broadcasters more optimistic about DAB's future. USADR and LOR worked jointly for about 10 months but ended their alliance early in 1998. Digital Radio Express (DRE), another IBOC developer, allied with USADR in late 1999. In October 1998 USADR petitioned the FCC to open a rulemaking proceeding to make its system the DAB standard. In 1999 a number of the larger U.S. radio groups invested in USADR. USADR's new corporate status was important because it demonstrated that much of the radio business believed in !BOC. Other broadcasters and electronics manufacturers, including receiver makers, soon fell into line. At NAB's 1999 meeting in Las Vegas, some broadcasters and manufacturers called for a "Grand Alliance" like the one struck with digital television (DTV). Robert Struble, USADR president, accurately stated that as a coalition from the beginning, USADR already was the Grand Alliance.

     The FCC issued a DAB Notice of Proposed Rulemaking on 1 November 1999, more than nine years after its first Notice of Inquiry. The commission believed it was time to determine whether an !BOC model and/or a model utilizing new radio spectrum would be the best means of promptly introducing DAB service in the United States. By initiating this proceeding now, we can foster the further development of IBOC systems, as well as new-spectrum DAB alternatives, help DAB system proponents identify design issues of public interest dimension and, where possible, encourage modifications that advance these policy objectives.

     In October 2002, the FCC provisionally approved the technical standard offered by IBiquity digital, the company controlled by the 15 largest radio broadcasters. The system allows AM and FM broadcasters to begin transmitting digital signals while continuing to offer their analog service. Initial broadcast equipment began to reach the market in late 2002 while the first consumer receivers became available early in 2003.

     Fears remained, however, that using more of a station's frequency assignment (as the digitized signal does) might threaten some sub-carrier services such as reading for the blind, carried by many noncommercial stations. The FCC order allowed temporary authority for digital operation until such problems could be resolved. FM stations may offer digital signals at all hours, but AM stations are at least temporarily limited to day­ time hours only because of their more complex evening signal propagation.

DAB's Future

      Despite the impressive development of DAB in many parts of the world, its detractors had not been fully disarmed by the early 2000s. Many smaller and community radio operators had not been able to afford to pay for the still scarce capacity on multiplexes. The U.K.'s Community Media Association (CMA) which, in the early days of the development of DAB, had been led to believe that the new system would allow small­ scale not-for-profit stations to (at last) find a secure and wide­ spread outlet on a mass media, was bitterly disappointed when it became clear that both the transmission pattern and licensing structure would largely exclude their model of radio stations. The Association tended to view the licensing and regulatory structure of DAB in the U.K. as reinforcing the dominance of a few major institutional operators-the larger commercial radio groups and the BBC-whereas the CMA favored a greater plurality of ownership and control, as well as of the "voices" and perspectives able to gain access to the public airwaves. The increase in frequency allocation in DAB may help to increase the range and type of operators using DAB, but these arguments highlight tensions on the more fundamental political and economic questions of access and regulation of broadcasting.

     Other DAB detractors continued to question whether the public would embrace the new system en masse, in particular whether DAB receivers would ever fall in cost to the level where most listeners would be prepared to replace their many analogue radios and even whether there was sufficient interest in the increased choice of services to motivate listeners to make the digital switch. Many asked whether the text and other non­ audio services were merely gimmicks, leading such critics to dub the new system "TV without the pictures." Whereas multi-channel digital TV had been embraced by the British consumer, it was often argued that radio was not perceived as providing the same level of sophisticated entertainment, information, and education, with a consequence that many citizens were reluctant to pay a premium for increased radio services or the claimed increase in audio quality. Certainly, the early and sometimes persistent claims that DAB provided CD-quality sound had rebounded, amid complaints that the sound quality on many of the individual stations on the multiplexes had been degraded in order to accommodate more services. Broadcasters admitted they had to make compromises between program choice and sound quality.

     There was also the continuing, nagging question as to whether the U.K. had backed the wrong system. Putting aside the argument as to whether radio needed to go digital at all, were the alternative and fast-developing standards such as IBOC likely, in the long term at least, to provide a more cost­ effective, easily received, radio system? Furthermore, the integration and fast development of mobile (cell) phone technology and the internet, especially with broadband access, confuses and even threatens the concept of "radio" as a separate and distinct medium.

     It may well be that the EUREKA 147 system, although undoubtedly a proven, sophisticated, and robust transmission standard, will prove too complex for sufficiently cheap receivers to be produced for the mass market, thus making the system commercially viable. The refusal of governments and broadcasters in the United States and Japan-the world's two largest economies-to adopt the EUREKA system, and the subsequent reluctance of some of the major manufacturers to develop inexpensive receivers, has prevented EUREKA from becoming the world standard. In the long term, the answer may be for receivers and transmitters to operate a "pick and mix" system: terrestrial IBOC for existing broadcasters and EUREKA for new ones. The development of the WorldSpace, Sirius, and XM Radio satellite-transmitted systems will also be followed with great interest to see if they are successful in developing their respective markets.