Difference between revisions of "Main Page"

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= Opendigitalradio.org =
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<div style="font-size:282%">Opendigitalradio.org</div>
  
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Easy digital broadcasting techniques based on software radio. Tips, Tricks and Experimentations.
 
  
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<P>
  
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<BIG>
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Open techniques for Digital Radio Broadcasting
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</BIG>
  
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==DAB, DAB+ and T-DMB transmission==
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{| style="width:100%; border-spacing:8px; margin:-8px -8px;"
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{| cellpadding="2" cellspacing="5" style="width:100%; vertical-align:top; background:#faf5ff; color:#000"
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! <h2 style="margin:0; background:#ddcef2; font-size:120%; font-weight:bold; border:1px solid #afa3bf; text-align:left; color:#000; padding:0.2em 0.4em;">Background</h2>
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Open digital broadcasting techniques based on software defined radio. Digital radio transmission and development must also become democratized for experimenters and small broadcasters. Opendigitalradio.org wiki is about creating a community for documenting and exchanging experimentations and gather information about existing small-scale DAB projects. Please read [[Introduction]] for more information.
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'''[[Association Opendigitalradio|Opendigitalradio is a non-profit association based in Switzerland]]''' (page in french), offering also a broadcast infrastructure for temporary radio stations.
  
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DAB, DAB+ and T-DMB European digital radio and mobile television standards share the same transmission system. It based on [http://en.wikipedia.org/wiki/Orthogonal_frequency-division_multiplexing OFDM] and use 1.5MHz of spectrum in VHF television band 3 (or L-band in SHF)
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This wiki is also the home of the '''ODR-mmbTools''', the continuation of the CRC-mmbTools from [http://mmbtools.crc.ca CRC]. Please see [[Introduction on DAB/DAB+]]
  
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Transmitting using this technology usually requires complex and costly equipment out of reach of individuals.  
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Have a look at the [http://opendigitalradio.github.io/mmbtools-doc/mmbtools.pdf guide]
  
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However, since the democratization of software defined radio (SDR) and the development of [http://mmbtools.crc.ca MMBTools set made by CRC], it is now possible to run a full transmission infrastructure on a laptop using a [http://en.wikipedia.org/wiki/USRP USRP].
 
  
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The transmission chain can be divided in 4:
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[[News|Older news]]
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*The encoding: encoding the sound to MPEG-2 Layer II for DAB, MPEG-4 HE-AACv2 for DAB+ or video in MPEG-4 H.264 for T-DMB.
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*The Multiplexer: gather different streams, produce necessary signalling and output a single 2Mbit/s stream in ETI format (Ensemble Transport Interface) 
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*The Modulator: take the ETI stream and produce the complex OFDM signal ready for upconverted at the desired  radio frequency.
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*The RF transmission performed by the USRP using appropriate RF daughterboards (Basic TX or modified RFX400)
 
  
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CRC has recently opened the source code of the multiplexer. However as the modulator depends on other developments that are not ready to open the source, it is free but closed source. The MPEG encoding is subject ot royalty payment and so CRC is selling it at the price of the royalty.
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However with the modular approach from these tools it is possible to interface it with other implementations. If there's no other software OFDM DAB modulator implementation at the moment, for the encoding it is possible to re-use TooLame that is an implementation of MPEG-2 Layer II.
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! <h2 style="margin:0; background:#cef2e0; font-size:120%; font-weight:bold; border:1px solid #afa3bf; text-align:left; color:#000; padding:0.2em 0.4em;">DAB/DAB+ transmission</h2>
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[[Image:Logo mmb.png|right]]
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*[[Introduction on DAB/DAB+]]
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*[[DAB/DAB+ encoding]]: MPEG Layer II or HE-AAC encoding, slideshow encoding
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*[[DAB multiplexing]]: putting together DAB/DAB+/DMB programs
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*[[DAB modulation]]: create the baseband COFDM modulation
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*[[DAB hardware]]: software radio peripheral, filtering, amplification
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*[[Example of live re-transmission on DAB of an Internet Radio radio station]]
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{| cellpadding="2" cellspacing="5" style="width:100%; vertical-align:top; background:#f5fffa; color:#000"
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! <h2 style="margin:0; background:#cef2e0; font-size:120%; font-weight:bold; border:1px solid #afa3bf; text-align:left; color:#000; padding:0.2em 0.4em;">Real cases, examples</h2>
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The ODR-mmbTools are used in several real-world 24/7 broadcasts, as shown on http://www.opendigitalradio.org/software
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A recipe for a low cost DAB transmission chain for local broadcasts based on the ODR-mmbTools is the [[RaspDAB]] description.
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Older presentations:
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*[http://www.slideshare.net/radioradioradio/local-dab-broadcasting Presentation] and [[WorldDMB GA 2010 Open DAB demonstration|demonstration]] of the full open source DAB transmission solution at 2010 WorldDMB General Assembly in Belfast
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*[[First licensed open dab transmission]] for Label Suisse Festival 17-19 September 2010 Lausanne.
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*[[Demonstration of open source digital transmission chain at IBC]], Stand 10.D21 (EBU), 10-14 September 2010
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*[[DAB scripts examples]]
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*[[Installer scripts]] for '''Debian'''
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*[[How to configure SPI (Service and Programme Information) for ODR-DabMux]]
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! <h2 style="margin:0; background:#f2e0ce; font-size:120%; font-weight:bold; border:1px solid #afa3bf; text-align:left; color:#000; padding:0.2em 0.4em;">Other digital systems, transmission and reception</h2>
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*[[DAB reception]] (Openmokast and others)
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*[[DAB measurement]] (measurement&monitoring tools, planning tools).
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*[[DRM/DRM+ Digital Radio Mondiale]], digital radio system for AM bands (LW, MW and SW) and all VHF bands (FM band and others).
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*[[FM RDS transmission]] (not really a digital system except RDS ;)
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*[[Crazy techniques using a VGA card as radio peripheral]]
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*[[Coverage planning]]
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! <h2 style="margin:0; background:#cedff2; font-size:120%; font-weight:bold; border:1px solid #afa3bf; text-align:left; color:#000; padding:0.2em 0.4em;">Contacts</h2>
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Please follow the odr-mmbtools discussion on groups.io for bug reports, solutions and updates. See the webiste https://groups.io/g/odr-mmbtools how to subscribe. This is the follow up of the crc-mmbtools mailing list on googlegroups (https://groups.google.com/g/crc-mmbtools) , which is still available to check for solutions to older problems.
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Follow us on '''Twitter''': http://twitter.com/opendigiradio to get informed, involved or for any questions. Find us [http://www.facebook.com/opendigitalradio also on '''Facebook''']
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Email: broadcast at opendigitalradio.org
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Latest revision as of 13:54, 27 May 2023

Opendigitalradio.org


Open techniques for Digital Radio Broadcasting

Background

Open digital broadcasting techniques based on software defined radio. Digital radio transmission and development must also become democratized for experimenters and small broadcasters. Opendigitalradio.org wiki is about creating a community for documenting and exchanging experimentations and gather information about existing small-scale DAB projects. Please read Introduction for more information. Opendigitalradio is a non-profit association based in Switzerland (page in french), offering also a broadcast infrastructure for temporary radio stations.

This wiki is also the home of the ODR-mmbTools, the continuation of the CRC-mmbTools from CRC. Please see Introduction on DAB/DAB+

Have a look at the guide


Older news

DAB/DAB+ transmission

Logo mmb.png

Real cases, examples

The ODR-mmbTools are used in several real-world 24/7 broadcasts, as shown on http://www.opendigitalradio.org/software

A recipe for a low cost DAB transmission chain for local broadcasts based on the ODR-mmbTools is the RaspDAB description.

Older presentations:

Other digital systems, transmission and reception

Contacts

Please follow the odr-mmbtools discussion on groups.io for bug reports, solutions and updates. See the webiste https://groups.io/g/odr-mmbtools how to subscribe. This is the follow up of the crc-mmbtools mailing list on googlegroups (https://groups.google.com/g/crc-mmbtools) , which is still available to check for solutions to older problems.

Follow us on Twitter: http://twitter.com/opendigiradio to get informed, involved or for any questions. Find us also on Facebook

Email: broadcast at opendigitalradio.org

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