Digital Radio Mondiale (DRM) is a set of digital audio broadcasting technologies designed to work over the bands currently used for AM broadcast, particularly shortwave. DRM can fit more channels than AM, at higher quality, into a given amount of bandwidth, using various MPEG-4 codecs. This article needs to be cleaned up to conform to a higher standard of quality. ... Amplitude modulation (AM) is a technique used in electronic communication, most commonly for transmitting information via a radio carrier wave. ... A solid-state, analog shortwave receiver Shortwave radio operates between the frequencies of 3 MHz (3,000 kHz) and 30 MHz (30,000 kHz) [1] and came to be referred to as such in the early days of radio because the wavelengths associated with this frequency range were shorter than... MPEG-4 is a standard used primarily to compress audio and visual (AV) digital data. ... A codec is a device or program capable of performing encoding and decoding on a digital data stream or signal. ...

It is also the name of the international non-profit consortium designing and implementing the platform. Radio France Internationale, TéléDiffusion de France, Deutsche Welle, Voice of America, Telefunken (now Transradio) and Thomcast (now Thomson SA) took part at the formation of the DRM consortium. A non-profit organization (often called non-profit org or simply non-profit or not-for-profit) can be seen as an organization that doesnt have a goal to make a profit. ... A consortium is an association of two or more individuals, companies, organisations or governments (or any combination of these entities) with the objective of participating in a common activity or pooling their resources for achieving a common goal. ... Radio France Internationale logo Radio France Internationale (RFI) was created in 1975 as part of Radio France by the Government of France to serve as a broadcast vehicle for French Equatorial Africa. ... This article is about the German international broadcaster. ... Voice of America logo Voice of America (VOA), is the official external radio and television broadcasting service of the United States federal government. ... Telefunken is a German radio- and television company, founded in 1903. ... In 2005, Telefunken SenderSysteme Berlin changed its name to Transradio SenderSysteme Berlin AG. The name Transradio dates back to 1918 when Transradio was founded as a subsidiary of Telefunken. ... This article is about the media and entertainment company. ...

Features

DRM can deliver FM-comparable sound quality, but on frequencies below 30 MHz (long wave, medium wave and short wave), which allow for very-long-distance signal propagation. VHF is also under consideration, under the name "DRM+". DRM has been designed especially to use portions of older AM transmitter facilities such as antennas, avoiding major new investment. DRM is robust against the fading and interference which often plagues conventional broadcasting on these frequency ranges. In telecommunications, frequency modulation (FM) conveys information over a carrier wave by varying its frequency. ... Antenna tower of Crystal Palace transmitter, London A transmitter (sometimes abbreviated XMTR) is an electronic device which with the aid of an antenna propagates an electromagnetic signal such as radio, television, or other telecommunications. ...

The encoding and decoding can be performed with digital signal processing, so that a cheap embedded computer with a conventional transmitter and receiver can perform the rather complex encoding and decoding. Digital signal processing (DSP) is the study of signals in a digital representation and the processing methods of these signals. ... A router, an example of an embedded system. ...

As a digital medium, DRM can transmit other data besides the audio channels (datacasting) — as well as RDS-type metadata or program-associated data as Digital Audio Broadcasting (DAB) does. Unlike most other DAB systems, DRM uses in-band on-channel technology and can operate in a hybrid mode called Single Channel Simulcast, simulcasting both analog signal and digital signal. Datacasting is the broadcasting of data over a wide area via radio waves. ... Radio Data System, or RDS, is a standard for sending small amounts of digital information using conventional FM radio broadcasts. ... Metadata is data about data. ... Metadata (Greek: meta-+data information) means While this definition is commonly offered, it is also commonly not helpful. ... Digital Audio Broadcasting (DAB), also known as Eureka 147, is a technology for broadcasting of audio using digital radio transmission. ... In-band on-channel (IBOC) is a method of transmitting digital radio and analog radio broadcast signals simultaneously on the same frequency. ... // This article is about a biological term. ... A transverse mode of a beam of electromagnetic radiation is a particular intensity pattern of radiation measured in a plane perpendicular (i. ... Single Channel Simulcast one calls the simultaneous transmission of a similar amplitude-modulated and one after that digitally radio Mondiale - procedures of transferred signal in the same (SingleChannel Simulcast - SCS) or a neighbouring channel (MultiChannel Simulcast - MCS). ... Simulcast is a contraction of simultaneous broadcast, and refers to programs or events broadcast across more than one medium at the same time. ... An analog or analogue signal is an allergy continuous in both time and amplitude. ... The term digital signal is used to refer to more than one concept. ...

Status

The LW/MW/SW standard has been approved by the IEC, and the ITU has approved its use in most of the world. Approval for ITU region 2 (North and South America and the Pacific) is pending amendments to existing international agreements. The inaugural broadcast took place on June 16, 2003, in Geneva, Switzerland, at the ITU's annual World Radio Conference. The International Electrotechnical Commission (IEC) is an international standards organization dealing with electrical, electronic and related technologies. ... The International Telecommunication Union (ITU; French: Union internationale des télécommunications, Spanish: Unión Internacional de Telecomunicaciones) is an international organization established to standardize and regulate international radio and telecommunications. ... The International Telecommunication Union (ITU), in its International Radio Regulations, divides the world into three ITU regions for the purposes of managing the global radio spectrum. ... is the 167th day of the year (168th in leap years) in the Gregorian calendar. ... Year 2003 (MMIII) was a common year starting on Wednesday of the Gregorian calendar. ... Geneva (pronunciation //; French: Genève //, German:   //, Italian: Ginevra //, Romansh: Genevra) is the second most populous city in Switzerland (after Zürich), and is the most populous city of Romandy (the French-speaking part of Switzerland). ...

Current broadcasters include BBC World Service, Radio Luxembourg, biteXpress, Passion Radio, Radio Canada International, Deutsche Welle, Radio Netherlands, RTÉ, and Radio New Zealand international. The BBC World Service is one of the most widely recognised international broadcasters of radio programming, transmitting in 33 languages to many parts of the world. ... Radio Luxembourg (1933-1992, 2005-)was an important forerunner of pirate radio and modern commercial radio in Europe. ... This article is about the Sussex radio station. ... Radio Canada International (RCI) is the international broadcasting service of the Canadian Broadcasting Corporation (CBC). ... This article is about the German international broadcaster. ... Radio Netherlands (RNW, short for Radio Nederland Wereldomroep in Dutch) is a public radio and television network based in Hilversum, producing and transmitting programmes for international audiences outside the Netherlands. ... Radio Telefís Éireann (RTÉ; Irish for Radio and Television of Ireland) is the national publicly-funded broadcaster of Ireland. ...

Until now DRM receivers have typically used a personal computer. A few manufacturers are presently producing stand alone DRM receivers (Sangean, Morphy Richards, Starwaves). Kenwood and Fraunhofer presented a prototype standalone receiver chip in September 2006. It will be produced by STMicroelectronics. Himalaya demonstrated their two models in 2006. Kenwood Corporation ) (TYO: 6765 ) is a Japanese manufacturer of amateur radio as well as Hi-Fi and portable audio equipment. ... The Fraunhofer Society (German: Fraunhofer-Gesellschaft) is a German research organization with 58 institutes spread throughout Germany, each focusing on different fields of applied science (as opposed to the Max-Planck-Gesellschaft, which works primarily on basic science). ... STMicroelectronics is an international leading supplier of semiconductors. ...

Morphy Richards has recently announced the start of mass production DRM receivers, which are being promoted by the broadcaster Deutsche Welle ^[1]. The receivers cost under €200 or £199.99 in the UK (as of June 2007), and are expected to drop further as production continues. At the time of writing, Morphy Richards are only distributing these sets around Germany, Austria and the UK, but Europe-wide distribution is expected shortly, with grey importers using German sourced radios to distribute across Europe.

Digital Radio Mondiale is being considered by Ofcom for introduction in Britain in 2012 on the present AM medium wave band. The British Broadcasting Corporation BBC has announced that it is to undertake a trial of the digital radio mondiale (DRM) technology, which will allow it to explore digital radio using medium-wave frequencies. The trial will broadcast BBC Radio Devon using the new technology in the Plymouth area and will last for a year from the end of April 2007. Ofcom is a regulator for communication industries in the United Kingdom. ... For other uses, see BBC (disambiguation). ... BBC Radio Devon is the BBC Local Radio service for the English county of Devon, and began transmissions on 17 January 1983, replacing a previous breakfast show (Morning SouWest) for Devon and Cornwall broadcast on the local frequencies of Radio 4. ...

International regulation

On 28 September 2006, the Australian spectrum regulator, the Australian Communications and Media Authority, announced that it had "placed an embargo on frequency bands potentially suitable for use by broadcasting services using Digital Radio Mondiale..." being "5950–6200, 7100–7300, 9500–9900, 11650–12050, 13600–13800, 15100–15600, 17550–17900, 21450–21850 and 25670–26100 kHz^[2] is the 271st day of the year (272nd in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... Australian Communications and Media Authority is an Australian government agency whose main roles are to regulate broadcasting, radiocommunications and telecommunications, and to respresent Australian interests in international communications matters. ...

Technique

Audio source coding

Useful bit rates with DRM range from 8 kbit/s to 35 kbit/s for a standard 10 kHz bandwidth channel. It is possible to achieve bit rates up to 72 kbit/s by using 20 kHz wide channels^[3]. (For comparison, pure digital HD Radio can broadcast 20 kbit/s using 10 kHz width and up to 60 kbit/s using 20kHz bandwidth) ^[4] Useful bit rate depends also on other parameters like wanted robustness to errors (error coding), power needed (modulation scheme), robustness in regard to propagation conditions (multipath, doppler). So DRM offers the possibility to use different audio coding system (source coding) depending on the bitrate: HD Radio is an in-band on-channel (IBOC) digital radio system created by iBiquity for broadcasting via existing FM and AM radio stations. ...

• MPEG-4 HE-AAC (High Efficiency - Advanced Audio Coding). AAC is a perceptual coder suited for voice and music and the High Efficiency is an optional extension for reconstruction of high frequencies (SBR: spectral bandwidth replication) and stereo image (PS: Parametric Stereo). 24 kHz or 12 kHz sampling frequencies can be used for core AAC (no SBR) which correspond respectively to 48 kHz and 24 kHz when using SBR oversampling.
• MPEG-4 CELP which is a parametric coder suited for voice only (vocoder) but that is robust to errors and needs a small bit rate.
• MPEG-4 HVXC which is also a parametric coder for speech programs that uses an even smaller bitrate than CELP.

All codecs can optionally be combined with Spectral Band Replication. MPEG-4 is a standard used primarily to compress audio and visual (AV) digital data. ... High Efficiency AAC (HE-AAC) is a lossy data compression scheme for digital audio. ... MPEG-4 AAC DRM encoding as used in the iTunes Store Advanced Audio Coding (AAC) is a standardized, lossy compression and encoding scheme for digital audio. ... MPEG-4 is a standard used primarily to compress audio and visual (AV) digital data. ... CELP stands for Code Excited Linear Prediction and is a speech coding algorithm described by the US Federal Standard FIPS 1016. ... MPEG-4 is a standard used primarily to compress audio and visual (AV) digital data. ... Harmonic Vector Excitation Coding, abbreviated as HVXC is a speech coding algorithm used in MPEG-4 standard for very low bit rate speech coding. ... A codec is a device or program capable of performing encoding and decoding on a digital data stream or signal. ... Spectral band replication (SBR) is a technology to enhance audio or speech codecs, especially at low bit rates. ...

Broadcasters have some freedom of choice depending on the material they send. The most commonly used mode is HE-AAC (also called AAC+) that offers an acceptable audio quality somewhat comparable to FM broadcast. High Efficiency AAC (HE-AAC) is a lossy data compression scheme for digital audio. ...

Bandwidth

DRM broadcasting can be done on different bandwidths:

• 9 kHz or 10 kHz which are the standard bandwidth of an AM broadcasting channel so existing frequency plan can be reused.
• 4.5 kHz or 5 kHz which are half channels. The idea is to offer a possibility for the broadcaster to do simulcast and use half a channel for AM and the other half for DRM. However the resulting bit rate and audio quality is less.
• 18 kHz or 20 kHz which correspond to a coupling of two adjacent channels. It offers the possibility to offer a better audio quality or to multiplex audio channels in the same transmitter.

Simulcast is a contraction of simultaneous broadcast, and refers to programs or events broadcast across more than one medium at the same time. ...

Modulation

The modulation used for DRM is COFDM (Coded Orthogonal Frequency Division Multiplexing), where every carrier is modulated with QAM (Quadrature Amplitude Modulation) with a selectable error coding. Orthogonal frequency division modulation (OFDM, also called orthogonal frequency division multiplexing) is a technique for the modulation of digital information onto an analog carrier electromagnetic (e. ... QAM is a TLA that may stand for: Quadrature amplitude modulation Quality Assurance Management (qam. ...

The choice of transmission parameters depends on signal robustness wanted, propagation conditions. Transmission signal is affected by noise, interference, multipath wave propagation and Doppler effect. A source of waves moving to the left. ...

It is possible to choose among several error coding schemes and several modulation patterns: 64-QAM, 16-QAM and 4-QAM. OFDM modulation has some parameters that must be adjusted depending on propagation conditions. This is the carrier spacing which will determine the robustness against Doppler effect (which cause frequencies offsets, spread: Doppler spread) and OFDM guard interval which determine robustness against multipath propagation (which cause delay offsets, spread: delay spread). The DRM consortium has determined 4 different profiles corresponding to typical propagation conditions:

• A: Gaussian channel with very little multipath propagation and Doppler effect. This profile is suited for local or regional broadcasting.
• B: multipath propagation channel. This mode is suited for medium range transmission. It is nowadays frequently used.
• C: similar to mode B, but with better robustness to Doppler (more carrier spacing). This mode is suited for long distance transmission.
• D: similar to mode B, but with a resistance to large delay spread and Doppler spread. This case exists with adverse propagation conditions on very long distance transmissions. The useful bit rate for this profile is decreased.

The trade off between these profiles stands between robustness, resistance in regards to propagation conditions and useful bit rates for the service. This table presents some values depending on these profiles. The more the carrier spacing is the more the system is resistant to Doppler effect (Doppler spread). The more the guard interval is the more the system is resistant to long multipath propagation (delay spread).

The resulting low-bit rate digital information is modulated using COFDM. It can run in simulcast mode by switching between DRM and AM, and it is also prepared for linking to other alternatives (e.g. DAB or FM services). In telecommunications and computing, bit rate (sometimes written bitrate) is the frequency at which bits are passing a given (physical or metaphorical) point. It is quantified using the bit per second (bit/s) unit. ... In telecommunications, modulation is the process of varying a periodic waveform, i. ... Orthogonal frequency division modulation (OFDM, also called orthogonal frequency division multiplexing) is a technique for the modulation of digital information onto an analog carrier electromagnetic (e. ... Simulcast is a contraction of simultaneous broadcast, and refers to programs or events broadcast across more than one medium at the same time. ... Digital Audio Broadcasting (DAB), also known as Eureka 147, is a technology for broadcasting of audio using digital radio transmission. ...

DRM has been tested successfully on shortwave, mediumwave (with 9 as well as 10 kHz channel spacing) and longwave. A solid-state, analog shortwave receiver Shortwave radio operates between the frequencies of 3 MHz (3,000 kHz) and 30 MHz (30,000 kHz) [1] and came to be referred to as such in the early days of radio because the wavelengths associated with this frequency range were shorter than... Mediumwave radio transmissions serves as the most common band for broadcasting. ... A kilohertz (kHz) is a unit of frequency equal to 1,000 hertz (1,000 cycles per second). ... Channel spacing is a term used in radio frequency planning. ... This article does not cite any references or sources. ...

There is also a lower bandwidth two-way communication version of DRM as a replacement for SSB communications on HF ^[5]- note that it is NOT compatible with the official DRM specification.

The Dream software will receive the commercial versions and also limited transmission mode using the FAAC AAC encoder.

Error coding

Error coding can be chosen to be more or less robust.

This table show an example of useful bitrates depending on protection classes, OFDM propagation profiles (A or B), carrier modulation (16QAM or 64QAM) and channel bandwidth (9 or 10 kHz):

DRM Plus

While DRM currently covers the broadcasting bands below 30 MHz, the DRM consortium voted in March 2005 to begin the process of extending the system to the VHF bands up to 120 MHz. DRM Plus (DRM+) will be the name of this technology. Design, development and testing are expected to be completed by 2007-2009.

Wider bandwidth channels will be used, which will allow radio stations to use higher bit rates, thus providing higher audio quality. One likely channel bandwidth is 50 kHz, which will allow DRM Plus to carry radio stations at near CD-quality. A 100 kHz DRM+ channel has sufficient capacity to carry one mobile TV channel: it would be feasible to distribute mobile TV over DRM+ rather than DMB or DVB-H. A compact disc or CD is an optical disc used to store digital data, originally developed for storing digital audio. ... Digital Multimedia Broadcasting (DMB) is a digital radio transmission system for sending multimedia (radio, TV, and datacasting) to mobile devices such as mobile phones. ... DVB-H (Digital Video Broadcasting - Handheld) is a technical specification for bringing broadcast services to handheld receivers. ...

References

1. ^ article: DRM radios available internationally for less than 200 €
2. ^ article: ACMA embargoes spectrum to plan for Digital Radio Mondiale
3. ^ Broadcasters' User Manual [pdf file, 4.5 MB], includes table of available bit rates (pp.19)
4. ^ The Structure and Generation of Robust Waveforms for AM In-Band On-Channel Digital Broadcasting
5. ^ WinDRM - software for Audio and Fast Data over HF SSB

• Digital Radio Mondiale - Consortium Agreement
• ETSI Standard: Digital Radio Mondiale (DRM); System Specification, ETSI ES 201 980 V2.1.1 (2005-10)
• ETSI Standard: Digital Radio Mondiale (DRM); Multiplex Distribution Interface (MDI), ETSI TS 102 820 V1.2.1 (2005-10)
• ETSI Standard: Digital Radio Mondiale (DRM); AM Signalling System (AMSS), ETSI TS 102 386 V1.2.1 (2006-03)
• ETSI Standard: Digital Radio Mondiale (DRM); Receiver Status and Control Interface (RSCI), ETSI TS 102 349 V1.2.1 (2005-11)
• ETSI Standard: Digital Radio Mondiale (DRM); Data Applications Directory, ETSI TS 101 968 V1.2.1 (2004-02)
• ETSI Standard: Digital Radio Mondiale (DRM); Transportation and Binary Encoding Specification for Electronic Programme Guide (EPG), ETSI TS 102 371 V1.2.1 (2006-02)
• ETSI Standard: Digital Radio Mondiale (DRM); XML Specification for DAB Electronic Programme Guide (EPG), ETSI TS 102 818 V1.3.1 (2006-02)
• "Planning parameters" for digital sound broadcasting at frequencies below 30 MHz, ITU-R Recommendation BS.1615, (Question ITU-R 223/10) (payment required)
• DRM consortium website
• J.Stott: DRM — key technical features, article in the EBU technical review

Australian Communications and Media Authority is an Australian government agency whose main roles are to regulate broadcasting, radiocommunications and telecommunications, and to respresent Australian interests in international communications matters. ... High frequency (HF) radio frequencies are between 3 and 30 MHz. ... Single-sideband modulation (SSB) is a refinement of the technique of amplitude modulation designed to be more efficient in its use of electrical power and bandwidth. ... “EBU” redirects here. ...

See also

• AMSS AM signalling system
• Digital Audio Broadcasting (DAB)
• Digital Multimedia Broadcasting (DMB)
• DVB-H (Digital Video Broadcasting - Handhelds)
• DVB-T (Digital Video Broadcasting - Terrestrial)
• ETSI Satellite Digital Radio (SDR)
• HD Radio, American system for digital radio
• ISDB-T, Japanese system for digital radio and television
• Software licensing

The amplitude modulation signalling system (AMSS or the AM signalling system) is a digital system for adding low bit rate information to an analogue amplitude modulated broadcast signal in the same manner as the Radio Data System (RDS) for frequency modulated (FM) broadcast signals. ... Digital Audio Broadcasting (DAB), also known as Eureka 147, is a technology for broadcasting of audio using digital radio transmission. ... Digital Multimedia Broadcasting (DMB) is a digital radio transmission system for sending multimedia (radio, TV, and datacasting) to mobile devices such as mobile phones. ... DVB-H (Digital Video Broadcasting - Handheld) is a technical specification for bringing broadcast services to handheld receivers. ... DVB-T stands for Digital Video Broadcasting - Terrestrial and it is the DVB European consortium standard for the broadcast transmission of digital terrestrial television. ... Satellite Digital Radio (SDR) is an activity of the standardisation organisation ETSI. It addresses broadcast systems where a satellite transmits directly to mobile and handheld receivers and is complemented by terrestrial transmitters. ... HD Radio is an in-band on-channel (IBOC) digital radio system created by iBiquity for broadcasting via existing FM and AM radio stations. ... Integrated Services Digital Broadcasting (ISDB) is the digital television (DTV) and digital audio broadcasting (DAB) format. ... It has been suggested that this article or section be merged into Software license. ...

External links

The external links in this article may not comply with Wikipedia's content policies. Please improve this article by removing excessive or inappropriate external links.

Image File history File links Broom_icon. ...

DRM in general

• Digital Radio Mondiale (DRM) - official homepage
• DRM Info with transmitter pictures
• Map of DRM capable transmitter sites worldwide with frequency schedule etc.
• (pdf) DRM - progress on the receiver front
• A Listeners' Guide to Digital AM (DRM)
• DRM Patent Licensing
• DRM - Digital Radio Mondiale - Digital AM radio below 30 MHz
• UK Digital Radio News
• DRM Digital Radio - A broadcasters view of the future

DRM broadcast transmitter manufacturers

• TRANSRADIO, Germany - DRM Signal Generator DRM DMOD2 and DRM Transmitters
• THOMSON Broadcast & Multimedia AG, Switzerland/France - DRM Transmitters on MF and HF, DRM Encoder/Multiplexer/Modulator/Measurement Receivers
• RIZ Transmitters Co., Croatia - DRM Transmitters on MW, SW, HF, DRM Encoder/Multiplexer/Modulator

DRM software

• DRM Software Radio developed by the Fraunhofer IIS
• Dream DRM receiver. An open source software radio published by the University Darmstadt (Germany)
• HamDream A modificated DREAM receiver supporting 2.5 kHz bandwidth.
• Diorama DRM receiver. An open source DRM receiver written in MATLAB by the Institute of Telecommunications of the University Kaiserslautern (Germany))
• Spark A DRM software transmitter developed by the University of Applied Sciences Kaiserslautern (Germany)
• WinDRM DRM software for amateur radio users.

Not to be confused with Matlab Upazila in Chandpur District, Bangladesh. ... Amateur radio station with modern solid-state transceiver featuring LCD display and DSP capabilities Amateur radio, often called ham radio, is a hobby that uses various types of radio broadcasting equipment to communicate with other radio amateurs for public service, recreation and self-training. ...

DRM radio techniques

• DRM Software Radio product
• DRM Receiver Modifications
• "bird-nest" DRM receiver
• Dream - an open-source software DRM Receiver
• Spark, a DRM signal generator (transmitter) software, University of Applied Sciences-Kaiserslautern Germany

DRM's COFDM

• "The how and why of COFDM" Jonathan Stott. EBU: EBU Technical Review 278 (winter 1998).
• Explaining some of the magic of COFDM, J H Stott (BBC): "COFDM is particularly well matched to these applications, since it is very tolerant of the effects of multipath."
• Coded Orthogonal Frequency Division Multiplexing (COFDM)
• All About OFDM from SSS Online and Pegasus Technologies
• OFDM, VOFDM, COFDM, Orthogonal Frequency Division Multiplexing: tutorials
• OFDM, VOFDM, COFDM, Orthogonal Frequency Division Multiplexing: resources
• COFDM/8-VSB Controversy Archive & Links

“EBU” redirects here. ... Orthogonal frequency division modulation (OFDM, also called orthogonal frequency division multiplexing) is a technique for the modulation of digital information onto an analog carrier electromagnetic (e. ... PRIMERGY MultiPath PRIMERGY MultiPath supports redundant Fiber Channel paths, the configured connections between server and subsystem that are such an important component of disaster-tolerant servers and clusters. ...

Index

• dmoz: Digital Broadcasting