digital audio around the world
TRANSCRIPT
Existing Broadcast Technology Standards
Since the 1970s, research engineers in many coun-
tries began looking at how the features and quality
of sound available from compact disc (CD) record-
ings could be achieved in a commer-
cial radio product called digital radio (DR). The
British Broadcasting Corporation (BBC) was
one of the earliest pioneers and proponents of
this technology. DR digitizes the analog signal for broadcast-
ing to receivers capable of decoding the digital signal.
There are currently four types of DR systems deployed
throughout the world. These systems are known as digital
audio broadcasting (DAB) system, digital radio mon-
diale (DRM), in-band on-channel (IBOC), and satellite
digital audio radio. These systems offer the following
advantages.
n DR reception is largely immune to inter-
ference. Digital signal processors depend
on receiving the ‘‘0s and 1s’’ necessary
for proper decoding into its analog source. If enough
‘‘0s and 1s’’ are not received, the receiver cannot
decode the signal, and nothing will be heard from
the receiver.
n They provide fixed, mobile, and portable reception
using simple low-gain antennas.Digital Object Identifier 10.1109/MVT.2010.939105
© DIGITAL VISION
Dennis Bodson
24 ||| 1556-6072/10/$26.00©2010IEEE IEEE VEHICULAR TECHNOLOGY MAGAZINE | DECEMBER 2010
n They are efficient in the use of the limited radio
frequency spectrum.
n They have the capability of operation from terrestrial
and/or satellite transmitters.
n Value-added system features will allow enhancements
such as text, graphics, and still-pictures. These features
provide the opportunity to introduce new innovative
services, such as multimedia radio-with-pictures and
broadcast Web sites on commercial amplitude-modula-
tion (AM) and frequency-modulation (FM) receivers.
The BBC asked Eureka, an international consortium
of broadcasters, network operators, consumer electronic
industries, and research institutes, for guidance on standards
and implementation schemes for DR. In response to this
request, Eureka initiated a project in January 1987 titled DAB
system. This system was developed as the 147 Project for the
European Union and resulted in the European Telecommuni-
cations Standards Institute (ETSI) DAB standard ETS 300 401.
Since then, the International Telecommunication Union (ITU)
has developed several DAB standards for various frequency
ranges. DAB is currently broadcast on terrestrial networks,
with prospects for satellite broadcasting in the future. The
ETSI and ITU standards are shown in Table 1.
A user can receive the terrestrial DAB programs using a
small nondirectional stub antenna. In addition to receiving
audio entertainment, programs can also be accompanied
by text, such as song lyrics, data, pictures, and videos.
Weather forecasts could be accompanied by a satellite
map of the area in which you are listening. This will also
allow you to determine where you are. Emergency
vehicles will be able to find their way to a fire or an acci-
dent because transmitted maps can be regularly updated,
displaying traffic jams and road works and suggested
diversion routes [1].
In order for DR to be successful, it needs to be widely
adopted. The availability of dedicated frequency spectrum
is the principal challenge to adoption especially in the
United States. In Europe, many countries have allocated
spectrum for DR (Eureka 147/DAB system) in the L-band
(1,452–1,492 MHz). The United Kingdom has provided allo-
cations in Band III (217.5–230 MHz), whereas France and
Germany have provided spectrum in both the L-band
and Band III. The United States cannot implement a Eureka
147/DAB system because there is no available spectrum
below 3 GHz for terrestrial use. However, DR can be imple-
mented in the United States through spectrum reuse. This
is discussed later in the paper.
Description of Past, Current,
and Future Technology
Eureka 147 DAB
The Eureka 147 DAB system is a reliable, multiservice, DR
broadcasting system for mobile, fixed, and portable
receivers, is capable of operation at any frequency from
30 MHz to 3 GHz, and can be used on terrestrial, satellite,
hybrid, and cable broadcast networks. It uses simple non-
directional antennas. The DAB signal is specified in ETSI
specification, EN 300 401 (second edition) [5]. Four differ-
ent modes of operation are allowed: mode I (<375 MHz),
mode II (<1.5 GHz), and mode III (<3 GHz) are optimized
for the frequency range in which they are operating. Mode
IV (<1.5 GHz) operates in the same spectral range as mode
II but increases the coverage range at the expense of
poorer Doppler Shift performance. Canada and many Euro-
pean countries have supported the dedicated spectrum
strategy using the Eureka 147/DAB system. Also, this ap-
proach is favored by the FM community.
The Eureka 147 system comprises three main elements:
n masking pattern universal sub-band integrated coding
and multiplexing (MUSICAM) audio encoding
n transmission coding and multiplexing (TCM)
n coded orthogonal frequency division multiplexing
(COFDM) modulation.
MUSICAM uses MPEG2 Audio Layer II encoding as
specified for International Organization for Standards
(ISO) Standard 11172-3. This exploits knowledge of the
properties of the human auditory system, in particular,
DECEMBER 2010 | IEEE VEHICULAR TECHNOLOGY MAGAZINE ||| 25
the spectral and temporal masking characteristic of the inner
ear. MUSICAM encodes only audio signal components that
the ear will hear. It discards any audio information that,
according to the psychoacoustical model, the ear will not
perceive. The principal of audio masking is shown in Figure 1.
A signal component at 1 kHz distorts and raises the
masking threshold, which defines the level other signal
components must exceed to be audible. If a second audio
component is present and close in frequency to the first, it
will not be perceived the ear unless it is at a higher audio
level than the distorted threshold. Therefore, it is effec-
tively masked by the first component.
TCM is the process by which data for individual services
are combined, or multiplexed, into a single data stream
ready for transmission. As shown in Figure 2, the multi-
plexed DAB frame is comprised of three distinct elements.
n The synchronization channel contains reference fre-
quency and timing information to allow receivers to
synchronize to and decode the received signals.
n The fast information channel contains information
describing the composition of frame and tells the
receiver how to extract and decode the signal.
n The main service channel (MSC) contains the audio
components and/or data packets corresponding to
the different services available within the frame. This
part of the multiplex is essentially the useful payload
of the DAB signal.
The gross data capacity for the entire DAB signal is
approximately 3 Mb/s, of which the MSC occupies approx-
imately 2.3 Mb/s. After allowing for the redundancy pro-
vided by the channel encoding, a net useful payload in the
range of 0.6–1.7 Mb/s is available.
COFDM is a multicarrier digi-
tal modulation scheme used in
DAB systems. It was developed to
improve bandwidth efficiency and
DAB performance in the presence
of multipath interference. Instead
of having a single digitally modu-
lated carrier with a high symbol
rate, COFDM uses multiple carriers
(up to 1,536) spaced at 1 kHz sepa-
ration. Each carrier is independently
modulated using differential quadra-
ture, phase shift keying. The TCM
data are distributed among all the
carriers, occupying approximately
60
40
20
00.02 0.5 0.1 0.2 0.5 1 2
Frequency (kHz)
Sou
ndP
ress
ure
Leve
l (dB
)
5 10 20
AB
C
D
A Normal Threshold of HeadingB Modified Threshold Due to Tone CD Band of Noise Rendered Inaudible by the Presence of Tone C
FIGURE 1 Psychoacoustical masking [5].
TABLE 1 ETSI and ITU DAB standards.
Identification Number Title Published
ETS 300 401 Edition 1 DAB; DAB to mobile, portable, and fixed receivers October 1995ETS 300 401 Edition 2 Radio broadcasting systems; DAB; DAB to mobile,
portable, and fixed receiversMay 1997
ITU-R BO. 1130-4 Systems for digital satellite broadcasting tovehicular, portable, and fixed receivers in the bandsallocated to BSS (sound) in the frequency range1,400–2,700 MHz
April 2001
ITU-R BO. 789-2 Service for digital sound broadcasting to vehicular,portable, and fixed receivers for broadcastingsatellite service (sound) in the frequency range1,400–2,700 MHz
October 1995
ITU-R BS.1114-4 Systems for terrestrial digital sound broadcasting tovehicular, portable, and fixed receivers in thefrequency range 30–3,000 MHz
May 2003
BBC R1 BBC R2 BBC R3 BBC R4 BBCR5L
BBCParl
BBCSport
Synchronization Channel
Fast InformationChannel (FIC)
Main Service Channel (MSC)
• Multiplex Configuration Information (MCI)• Service Information (SI)• Other Data e.g., TMC
• Programme Services • Audio Data • Programme Associated Data (PAD)• Announcement Service• Additional SI, TMC
FIGURE 2 DAB multiplex frame structure [5].
26 ||| IEEE VEHICULAR TECHNOLOGY MAGAZINE | DECEMBER 2010
1.54 MHz of spectrum. Consequently, the symbol rate on
any individual carrier is much lower and results in a longer
symbol period. This affords some protection against multi-
path echoes where the receiver sees multiple signals from
a transmitter, some of which are delayed because of reflec-
tions from terrain and buildings.
Protection is enhanced by deliberately repeating part
of each symbol during the guard interval, as long as the
delay of the echo signals is less than the guard interval.
This also allows the broadcaster to use a single frequency
network (SFN) of transmitters, where ‘‘man-made multi-
paths’’ are deliberately created by having all the transmit-
ters in the network transmitting the same signal on the
same frequency. Broadcasting on an SFN is an efficient use
of the scarce RF spectrum available—a key advantage of
the Eureka 147/DAB system.
Digital Radio Mondiale
A DRM system uses the COFDM scheme and is designed to
fit within the existing AM broadcast band plan. It is based
on signals of 9-kHz bandwidth. It has modes requiring as
little as 4.5 kHz in bandwidth. The wideband versions offer
the best audio fidelity. It is designed so that the number of
carriers can be varied, depending on factors such as the
allotted channel bandwidth and degree of robustness
required. The robustness of the DRM signal can be chosen
to match different propagation conditions. DRM is the only
standard recognized internationally for high frequency
(HF) (or 3–30 MHz) use. Many existing AM transmitters can
be easily modified to carry DRM signals and can be used for
a range of audio content, including multilingual speech and
music, data, and text.
A DRM system can use three different types of audio
coding, depending on broadcasters’ preferences.
n MPEG4 advanced audio coding augmented by spec-
tral band replication bandwidth extension is used
as a general-purpose audio coder and provides the
highest quality.
n MPEG4 code excited linear prediction speech coding
is used for high-quality speech coding where there is
no musical content.
n Harmonic vector excitation coding speech coding can
be used to provide a very low bit-rate speech coder.
It should be noted that the U.S. Federal Communica-
tions Commission (FCC) has adopted the DRM standards
for U.S. HF Broadcasting [6].
Eureka147 Versus DRM
Radio broadcasters use both AM and FM to meet the
needs of their service areas. In the transition to DR, broad-
casters will, in all likelihood, continue to use existing facili-
ties and equipment due to economic considerations. FM
broadcasters favor Eureka because dedicated spectrum
exists for this system in the very high-frequency (30–300
MHz) portion of the spectrum. AM broadcasters favor
DRM because existing stations can be modified for digital
transmission within existing AM broadcasting bands. In
addition, DRM is the only internationally recognized
standard for HF use.
IBOC DAB System
IBOC refers to a method of transmitting DR broadcast sig-
nals centered on the same frequency as an existing AM or
FM station (referred to as AM and FM systems) but occu-
pying the sidebands above and below the station’s center
frequency. The digital emissions fall within the spectral
emission mask of the AM or FM channel. In 2002, the FCC
selected IBOC technology for the introduction of DR
broadcasting in the United States.
IBOC systems are comprised of four building blocks
similar to the Eureka 147/DAB’s major subsystems [7].
n Audio source coding: An audio codec is a source-
encoding device that filters out those parts of an ana-
log signal that are irrelevant to the human ear. When
decoded, the signal will not be identical to the origi-
nal but will be perceived to be the same.
n Channel coding: The output stream from the audio
codec is encoded using forward error correction (FEC)
and interleaving in the transmission system. This
greatly improves the reliability of the transmitted infor-
mation by carefully adding redundant information used
to correct errors occurring in the transmission path.
Advanced FEC coding techniques have been specifically
designed for AM systems based on detailed interfer-
ence studies to exploit the nonuniform nature of inter-
ference in the AM bands.
n Modulation/demodulation techniques: A modem is a
device that modulates a signal or demodulates it. AM
systems use quadrature AM scheme in conjunction with
orthogonal frequency-division multiplexing (OFDM).
FM systems also uses OFDM modulation but with the
carriers modulated with quadrature phase-shift key-
ing (QPSK) modulation scheme.
n Blending: Blending is a technique employed in IBOC
DAB systems to seamlessly switch between digital-to-
analog signals. Essentially, blending allows transition
from the instantly acquired analog signal (such as
when the receiver is first turned on) to the digital
signal (after the receiver has acquired, decoded,
and processed the signal). Once the digital signal is
acquired, the receiver will transition to it in a seam-
less fashion. Should the digital signal become cor-
rupted the receiver will seamlessly switch to the
analog signal.
DIGITAL RADIO DIGITIZES THE ANALOGSIGNAL FOR BROADCASTING TO RECEIVERSCAPABLE OF DECODING THE DIGITAL SIGNAL.
DECEMBER 2010 | IEEE VEHICULAR TECHNOLOGY MAGAZINE ||| 27
AM systems and analog AM stations operate in the HF
band. During daytime operations, the coverage area for an
AM system is comparable to, and slightly exceeds, current
analog AM stations. However, during nighttime operations,
HF propagation mode changes from ground wave only to a
combination of ground wave and sky wave propagation.
This combination of propagation modes expands the cover-
age area and introduces multipath interference. Multipath
interference corrupts the digital signal to a point where it
becomes incoherent, thus reducing the effective AM system
range. As a result, analog AM stations have a greater cover-
age area at night than digital AM systems.
The signal footprint for analog FM and for FM-based
systems is about the same. However, the signal penetra-
tion for an FM system is far better than an FM station. In
addition, the FM system provides significant improvements
in signal availability and quality (frequency response, noise,
and distortion).
n Four IBOC DAB systems have been developed in the
United States. Three of these systems were designed
to operate in the existing FM broadcast band, while
one system was designed to operate in the AM broad-
cast band. Developers of FM systems include Amanti
Communications in partnership with AT&T (circa
1991), U.S. digital radio (USADR), a limited partner-
ship between CBS, Gannett, and Westinghouse Elec-
tric (also formed in 1991). USADR also developed an
IBOC DAB for the AM band. Amanti Communications
got out of the business in the mid-1990s. USADR and
Lucent Technologies (which was spun-off from AT&T)
entered into a partnership (circa 1996) for IBOC develop-
ment. This relationship ended in 1998 when Lucent broke
away and formed lucent digital radio (LDR). USADR and
LDR were now competitors. In July 2000, these two com-
petitors merged into the sole surviving developer of
IBOC technology, iBiquity Digital Corporation.
iBiquity uses a technology known as HD radio. In addi-
tion to the benefits of IBOC DAB systems previously dis-
cussed, this technology has the capability to provide:
n wireless data services to include on-demand audio or
the streaming of audio content providing more infor-
mation on station programs, news, weather, and traf-
fic; other services can include the display of artist
and song information and mobile commerce options
n backward and forward compatibility, which allows a
user to purchase a digital receiver that will receive
traditional analog broadcasts from stations who have
not convert to HD radio and digital broadcasts from
stations that have.
Transition to DR will require broadcasters to install
new transmission equipment. During the transition,
broadcasters will operate in a ‘‘hybrid’’ mode, broadcast-
ing both analog and digital signals. During hybrid opera-
tions, stations will broadcast the same programming in
both analog and digital formats. New receivers being
developed will incorporate both modes of reception,
where the receiver will automatically switch to the analog
signal if the digital signal cannot be decoded or is lost by
the receiver.
Software-Defined Radio
A software-defined radio (SDR) is equipment that can be
reprogrammed quickly to receive signals within a wide
range of frequencies, and in any transmission format or
set of standards [4]. SDRs currently exist and examples
include personal digital assistants (PDAs), cell phones,
and amateur radios. SDR provides an efficient and compa-
ratively inexpensive solution to the problem of building
multimode, multiband, or multifunctional wireless devices
and can be considered an enabling technology that is
applicable across a wide range of areas within the wireless
industry. Features of an SDR include:
n standard, open, and flexible architectures for a wide
range of communication products
n enhanced roaming by extending the capabilities of cur-
rent and emerging commercial air-interface standards
n over-the-air downloads of new features and services,
such as software patches
n unified communications across commercial, civil, fed-
eral, and military organizations.
An SDR system can be viewed as one in which the base-
band processing as well as digital down conversion/digital
up conversion modules are programmable. Availability
of smart antennas, wideband RF front-ends, wideband
A/D and D/A converters, and ever increasing processing
capacity of digital signal processors and general-purpose
microprocessors have fostered the development of multi-
band, multimode radio systems.
Figure 3 illustrates the software architecture of a typi-
cal SDR system. The system uses a generic hardware plat-
form with programmable intermediate frequency and
baseband modules and analog RF modules. The operating
environment performs hardware resource management
activities such as allocation of resources to different appli-
cations, memory management, interrupt servicing, and
providing a consistent interface to hardware modules for
use by applications. In an SDR system, the software mod-
ules that implement link-layer protocols and modulation/
demodulation operations are called radio applications
and provide link-layer services to higher layer communi-
cation protocols such as wireless application protocol
and transmission control protocol/Internet protocol.
TCM IS THE PROCESS BY WHICH DATA FORINDIVIDUAL SERVICES ARE COMBINED, ORMULTIPLEXED, INTO A SINGLE DATA STREAMREADY FOR TRANSMISSION.
28 ||| IEEE VEHICULAR TECHNOLOGY MAGAZINE | DECEMBER 2010
Satellite Digital Audio Radio Services
There is a new type of DR broadcasting called satel-
lite digital audio radio services (SDARSs). With SDARS,
listeners will be able to tune in to the same radio sta-
tions anywhere in the United States. There are two DR
systems providing SDARS, Sirius Satellite Radio, and XM
Satellite Radio.
From a technical standpoint, the Sirius and XM Satellite
systems are unique in a number of ways. In the XM system,
two satellites in a conventional geostationary orbit, one at
85� W longitude and the other at 115� W longitudes, are
used. These locations afford optimum coverage of the
United States. Sirius uses three satellites in highly elliptical
orbits rising and setting approximately every 16 h. As a
result, two of the three satellites are visible to receivers in
the United States at any given time. Because of their orbits,
the Sirius satellites are higher in the sky and less likely to
be blocked by buildings, trees, or mountains.
Three specific techniques, each representing a differ-
ent kind of redundancy, spatial, frequency, and time
Higher Level Protocols (WAP, TCP/IP)
Radio Applications (Link-Layer Protocols,Modulation/Demodulation)
Operating Environment (Hardware Resource Management,Memory Management, Interrupt Management)
Hardware Resources (DSPs, FPGAs, Microprocessors,Memory, Analog RF Hardware Including Antenna)
FIGURE 3 Architecture of software components in a typical
SDR system. WAP: wireless access protocol; TCP/IP: transmission
protocol procedure/Internet Protocol; DSP: digital signal processor;
and FPGA: field programmable gate array.
TABLE 2 U.S. Satellite digital audio radio service [3].
Parameter
Satellite radio
CommentsSirius XM
In orbitNo. satellites (longitude) 3 (nominal 100� W) 2 (85� and 115� W) Sirius satellites are in a highly
elliptical orbit, rising andsetting every 16; hours; XMtypes are geostationary
Uplink frequencies 7,060–7,072.5 MHz 7,050–7,075 MHz Sirius also uses Ku-band(14–12 GHz) uplink to feedrepeaters
Downlink frequencies 2,320.0–2,324.0 MHz and2,328.5–2,332.5 MHz
2,332.5–2,336.5 MHz and2,341.0–2,345.0
Redundant downlink signalsare for spatial/frequency/timediversity
Satellite elevation angle 60� 45� Typical
On landLocation New York City Washington, D.C. —No. studios 75 82 In main facilityNo. terrestrial repeaters 105 (46 markets) 1500 (70 markets) Approximate numbersRepeater equivalentisotropic radiated power
Up to 40 kW 90% are 2 kW —
Other characteristicsNo. CD-quality (64-kb/s)channels
50 Lower-quality services use0.5–64 kb/s
No. news-talk-sportschannels
50 System is reconfigurable onthe fly
Satellite modulation TDM-QPSK Each carrier is about4 MHz wide
Terrestrial repeatermodulation
TDM-COFDM Carrier ensemble is about4 MHz wide
Channel coding scheme Concatenated Error-correcting Reed-Solomonouter code and rate 1/2convolutional inner code
Source coding scheme Lucent Perceptual Audio Coder Nominal rate for top-qualitymusic: 64 kb/s
Transmission Rate 4.4 Mb/s 4.0 Mb/s Before channel coding
It should be noted that XM and Sirius Merged on 29 July 2009 [8]. TDM ¼ time-division multiplexing. Source: Sirius Satellite Radio, XM Satellite Radio.
A DRM SYSTEM USES THE COFDM SCHEMEAND IS DESIGNED TO FIT WITHIN THE EXISTINGAM BROADCAST BAND PLAN.
DECEMBER 2010 | IEEE VEHICULAR TECHNOLOGY MAGAZINE ||| 29
diversity, all are used by the SDARS services to enhance
performance.
n Spatial diversity comes from multiple satellites trans-
mitting essentially identical signals from two, widely
spaced locations in orbital planes and periods. An
SDARS receiver in a moving vehicle often will see
multiple satellites and be continuously receiving and
processing the signals from both. There will be times
when at least one of the satellites will be blocked by
an obstacle; in this case, the receiver will have to rely
upon the signal from other (unblocked) satellites.
n The two other forms of diversity are frequency diver-
sity and time diversity. Frequency diversity is realized
by each satellite broadcasting the same signal but in
different frequency bands. This can help to combat
problems associated with multipath fading, where fad-
ing is frequency selective and usually limited to one
band or the other. Time diversity is implemented by
introducing a time delay in the signals broadcast
from the satellites and the signals broadcast from
their terrestrial repeaters. Time delays compensate
for differences in the distance between the satellites
and terrestrial repeaters.
The characteristics of Sirius and XM satellites radio
systems are shown in Table 2.
Observations and Conclusions
DR (or DAB) has been around for several decades but
only now is it being adopted and implemented by the
commercial broadcast community. There are four types
of systems: Eureka 147, DRM, IBOC, and Satellite Digital
Audio Radio. There are two types of implementation
strategies: use of dedicated spectrum and reuse of exist-
ing spectrum for AM and FM broadcasting. Eureka 147
uses dedicated spectrum; DRM and IBOC reuse existing
spectrum. In addition, SDAR makes use of terrestrial as
well as satellite systems (XM and Sirius). Digital tuner
costs vary from US$150.00 to US$1,000.00. Table 3 shows
a comparison of each type of system.
Although a principal purpose of DR is the enhance-
ment of audio quality, this technology offers additional
features such as the ability to integrate and broadcast
text, data, and video, weather service information, and
satellite maps of your location. In addition, DR technol-
ogy is adopting the use of software to defined radio
capabilities and features that will result in longer equip-
ment life cycles and using common equipment in
diverse applications.
Author Information
Dennis Bodson received his B.E.E. and M.E.E. degrees
in electrical engineering from The Catholic University of
America, Washington, DC, his Master’s degree in public
administration from the University of Southern Califor-
nia Washington Center for Public Affairs, DC, and his
Ph.D. degree in electrical engineering from California
Western University in 1961, 1963, 1976, and 1985, respec-
tively. He recently retired from federal service as the
chief of the Technology and Standards Division of the
National Communications System and has since been
self-employed as a consulting engineer in the informa-
tion technology field. He has published more than 60
technical articles, two books, and six patents. He won
several awards from both industry and government. He
is currently the director of the Roanoke Division of the
Amateur Radio Relay League and past president of the
IEEE Engineering Management Society and the IEEE
Vehicular Technology Society. He is a Fellow of the IEEE,
the IET, C’Eng UK, the Radio Club of America, and the
Washington Academy of Sciences.
References[1] D. M. L. Witherow and P. A. Lowen, ‘‘Digital audio broadcasting—The
future of radio,’’ in Proc. IEE Int. Broadcasting Convention Conf., Sept.14–18, 1995, pp. 57–61.
[2] H. W. H. Tuttlebee and D. A. Hawkins, ‘‘Consumer digital radio: Fromconcept to reality,’’ Electron. Commun. Eng. J., vol. 10, no. 6, pp. 263–276, Dec. 1998.
[3] D. H. Layer, ‘‘Digital radio takes to the road,’’ IEEE Spectr., vol. 38,no. 7, pp. 40–46, July 2001.
[4] H. Newton, Newton’s Telecom Dictionary, 21st ed. San Francisco, CA:CMP Books, 2005.
[5] A. J. Bower, ‘‘Digital radio—The Eureka147 DAB system,’’ Electron.Eng., pp. 55–56, Apr. 1998.
[6] FCC Adopts DRM System for US HF Broadcasting, May 10, 2005.[7] National Radio Systems Committee (NRSC), Digital Audio Broadcast-
ing (DAB) Subcommittee Report‘‘Evaluation of USA digital radio’ssubmission to the NRSC DAB subcommittee of selected laboratoryand field test results for its FM and AM band IBOC system,’’ Appendi-
ces D and IApr. 8, 2000.[8] ‘‘XM and Sirius Merger,’’ July 29, 2008.
TABLE 3 Digital radio feature characteristics.
Feature Supported in DR Technology
Eureka147/DAB DRM IBOC Satellite
Reuse of radiospectrum
No Yes Yes No
Radio spectrumspecifically allocatedfor DR
Yes No No No
CD quality sound Yes Yes Yes YesSupport terrestrial-based DR
Yes Yes Yes No
Wireless dataservices (text,graphics,weather, etc.)
Yes Yes Yes Yes
Backwardcompatibility withanalog radio
No Yes Yes No
Interferenceimmunity
Yes Yes Yes Yes
Equipmentavailability
Yes Yes Yes Yes
30 ||| IEEE VEHICULAR TECHNOLOGY MAGAZINE | DECEMBER 2010