The RDS for FM broadcasting in the frequency range 87.5–108.0 MHz was developed within the European Broadcasting Union (EBU), as explained in Chapter 1. This system was specified by the EBU in 1984, and has now been introduced in the large majority of European countries as well as a number of other countries all over the world. It is also now being used by a significant por- tion of the FM broadcast stations in the United States. Later, the system was enhanced through several modifications as more experience was gained during different implementations—in 1987, on large broadcast networks that were
39
then just starting and in 1990, when RDS was adopted as a European stan- dard of CENELEC (EN 50067:1990) [1]. Today, most FM radio stations in Western Europe and several FM radio stations in Central and Eastern Europe use RDS. Receivers—mostly car radios with RDS functionality—are available in Europe from some 75 different manufacturers at prices that are only slightly higher than those of conventional radios.
Although the RDS system offers a wide range of implementation options (some, like the TMC feature, just started implementation in 1997/98), most of the existing RDS car radios have only the five basic features: PI, PS name, AF list, TP identification, and TA signal. PTY code (see Chapter 4) will definitely be one of the popular features in the future, apart from the EON function (see Chapter 6), which is increasingly used now by the European broadcasting net- works, and which has led to a second-generation of RDS receivers.
In the United States, a subcommittee on Radio Broadcast Data Systems of the National Radio Systems Committee (NRSC), sponsored by the Elec- tronics Industry Association (EIA) and the National Association of Broadcast- ers (NAB), began its work in February 1990, after the EBU had demonstrated RDS at various NAB and SAE conventions. The NRSC based its work on RDS as specified within the EBU, and every attempt was made to keep the U.S. stan- dard compatible with it. However, it soon became evident that the completely different broadcasting structure of the United States required that a number of modifications be made. Finally, the U.S. standard had to cover FM broadcast- ing, as is the case in Europe, but it also had to have certain AM broadcasting- related extensions.
In January 1993, the EIA and the NAB jointly published the U.S. Stan- dard RBDS as a voluntary industry standard that was adopted through a voting procedure that involved both organisations [2].
Since the introduction of the RBDS standard in North America in 1993, much activity has surrounded the introduction of the system by both broad- casters and receiver manufacturers. The EIA created an advisory group to promote the technology to broadcasters and manufacturers, and the RBDS subcommittee remains active for the purpose of upgrading the standard as implementation experience brings about necessary changes. This is completely in line with what was done in Europe only six years earlier. Figure 2.1 shows the EIA booth at the 1993 Chicago Consumer Electronics Show.
Large coordination activities that surrounded the upgrade of the standard took place with the RDS Forum in Europe during the years 1994–1998, with the goal of achieving even more harmonisation between RDS and RBDS. The first result of this harmonisation was that the advisory group proposed the use, at the consumer level, of only one name for the system—namely, only RDS.
RBDS is kept as the name for the North American standard to keep it distinct
40 RDS: The Radio Data System
from the European RDS CENELEC standard, since there is no single world standard combining the elements of both standards.
Recent changes to both standards, which were officially adopted in early 1998, have resulted in a significant harmonisation of features, allowing the development of global broadcast equipment, consumer receivers, and data serv- ices. The newly revised RDS and RBDS standards both move forward into a new era for FM data services. All changes have been devised to be fully back- ward compatible with the prior standards while offering a tremendous amount for future growth and extension. The new ODA feature (see Chapter 9) will even permit the definition of additional functionality without the need to revise the RDS/RBDS standards yet again.
Figure 2.2 depicts the actual construction of the RBDS standard. As is shown in this functional diagram of the RBDS standard, the RDS standard is entirely contained within the RBDS standard, and this is true word by word;
that is, the corresponding text is identical with the copyright being agreed to by all the organisations concerned. In the RBDS standard, the few remaining functional differences are added within the appropriate sections of the text or within entirely new annexes. This reflects the fact that the functional core of RBDS is completely identical with RDS. This can also be seen by examining the RDS/RBDS group allocations shown in Table 2.1 [3,4].
Differences Between RDS and RBDS 41
Figure 2.1 RBDS promotion during the 1993 Chicago Consumer Electronics Show. From left to right: Casey (Denon), Haber (Radio World), Lebow (Sage Alert Systems), and Kopitz. (Source: EBU.)
42 RDS: The Radio Data System
NRSC RBDS standard
1998
CENELEC RDS standard EN50067 1998
Placeholder for AM RDS
Section 6
Specification for in-receiver
database system Section 7 and
Annex R
PI codes for North America Annex D
PTY codes for North America Annex F
Specification for MMBS radio paging
Annex P
Emergency alert system
Annex Q
= + + + + + +
Figure 2.2 Functional diagram of the RBDS standard. (Source: NAB/EIA.) Table 2.1
RDS/RBDS Data Groups Group Type Description of Usage
0A Basic tuning and switching information only 0B Basic tuning and switching information only 1A Programme Item Number and slow labelling codes
1B Programme Item Number
2A RadioText only
2B RadioText only
3A Applications IDentification for ODA only 3B Open Data Applications—ODA 4A Clock Time and date only 4B Open Data Application—sODA
5A Transparent Data Channels (32 channels) or ODA 5B Transparent Data Channels (32 channels) or ODA 6A In-House applications or ODA
6B In-House applications or ODA 7A Radio Paging or ODA 7B Open Data Application—sODA 8A Traffic Message Channel or ODA 8B Open Data Application—sODA 9A Emergency Warning System or ODA 9B Open Data Application—sODA
10A Programme TYpe Name
10B Open Data Application—sODA 11A Open Data Application—sODA 11B Open Data Application—sODA 12A Open Data Application—sODA 12B Open Data Application—sODA