Difference between revisions of "Main Page"

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<div style="font-size:282%">Opendigitalradio.org</div>
  
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<div style="font-size:282%"> Opendigitalradio.org </div>
 
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<br>
 
  
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<big> <b>Open and easy digital broadcasting techniques based on software radio - because digital radio transmission and development must also become democratized. </b></big>
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<P>
  
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Broadcasting is sometime considered, by the new generations, as a dying media that will be soon completely superseeded by Internet. However it is a nice, efficient and green way to reach masses without intermediaries but just using radio spectrum directly (despite the fact that the use spectrum is subject to licence). For these reasons and apart from the big public or private broadcasters interests, it has still an interest for local communities. In particular, it offers anonymous listening and is free-to-air (no subscription needed) which is of importance in poor countries or where freedom of information does not apply.
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<BIG>
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Open techniques for Digital Radio Broadcasting
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</BIG>
  
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In radio, Analog transmission using AM, FM is still very popular but may be replaced in the future by digital techniques such as DAB, DAB+, T-DMB, DRM (Digital Radio Mondiale) or DRM+.  
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In television analog transmission using PAL or SECAM is being stopped in Europe and replaced by DVB-T, DVB-T2, DVB-H (for mobile) or other digital satellite or cable transmission techniques.
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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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Transmitting using these technologies usually requires complex and costly equipment out of reach of individuals. However, since the democratization of software defined radio (SDR), a new field of possibilities opens for experimentation, micro networks, etc. In the longer term also if software based radio become also democratized in common receivers, it could even be possible to develop personalized broadccasting system based on free/open technologies for example. The combination of personal (Internet,..) networks and broadcast also offer interesting possibilities.
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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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So this website will focus on tips, tricks and techniques to produce and receive digital broadcast signals. Most of the content is based on development from research centers, groups or individuals that did the "real work". The objective of this website is to follow developments, integrate them and show applications.
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Have a look at the [http://opendigitalradio.github.io/mmbtools-doc/mmbtools.pdf guide]
  
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==NEWS==
 
  
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*'''Get involved or informed, register to the [https://lists.saitis.net/cgi-bin/mailman/listinfo/openradio mailing list]'''
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[[News|Older news]]
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*[http://events.ccc.de/congress/2009/wiki/Radio_broadcasting CCC Workshop] on digital radio and software radio.
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==DAB, DAB+ and T-DMB transmission==
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[[Image:dab1.jpg|thumbnail|Home setup]]
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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] modulation and use 1.5MHz of spectrum in VHF television band 3 (or L-band in SHF). A transmitter is broadcasting a set of programs, called a multiplex. The system has been designed for mobile use and is robust up to 300km/h.
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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;">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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With 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 running linux and using a [http://en.wikipedia.org/wiki/USRP USRP] as [[RF]] hardware (with [[wikipedia:gnuradio|gnuradio]]) or any other similar device.
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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 transmission chain can be divided in 4:
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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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*The encoding: encoding the sound to [[wikipedia:MPEG-1 Audio Layer II|MPEG-2 Layer II]] for DAB, [[wikipedia:High-Efficiency Advanced Audio Coding|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 [[wikipedia:baseband|baseband]] OFDM signal ready for upconvert 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, it is free but not opened. The MPEG-4 AAC encoding is subject to royalty payment and so CRC is selling it.  
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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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However thank to 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 [[wikipedia:TooLame|TooLame]] that is an implementation of MPEG-2 Layer II. Using another software modulator is also possible (gnuradio based ?).
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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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===Software===
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{| cellpadding="2" cellspacing="5" style="width:100%; vertical-align:top; background:#fffaf5; color:#000"
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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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*[[Example of live re-transmission on DAB of an Internet Radio radio station]]
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*'''[[Example of live re-broadcasting on DAB of many Internet radio stations]]'''
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*[[Example of the creation of a multiplex stream of 2 DAB stations]]
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*[[Example of the creation of a DAB+ transmission]]
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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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Info pages on tools
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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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*[[CRC-DabMux]] DAB/DAB+/T-DMB multiplexer
 
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*[[CRC-DabMod]] DAB modulator
 
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*[[CRC-Dwap.py]] USRP modulator and controller
 
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*[[toolame]] MPEG-Layer II encoder
 
  
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All questions and enquiries on MMBtools should be done directly on [http://mmbtools.crc.ca/component/option,com_fireboard/Itemid,55/ their forum]
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Email: broadcast at opendigitalradio.org
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[[Image:dab_s_1.jpg |thumbnail|right| USRP]]
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===Hardware===
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Find in this section some experiment done with USRP RF front end like Daughter boards or external devices.
 
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*[[Example of RF amplifier for DAB]] for VHF band III (never connect to an antenna without a license !)
 
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<br>
 
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<br>
 
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==Open DAB/DAB+/T-DMB software receiver==
 
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<big> '''Openmokast project'''</big>
 
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[[Image:Phon3b small.jpg|100px|right]]
 
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*http://www.openmokast.org
 
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Other:
 
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*[http://people.ee.ethz.ch/~andrmuel/files/gnuradio/ Gnuradio blocks for DAB reception] (developments from Andreas Mueller, ETHZ)
 
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Under construction
 
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==Digital Radio Mondiale (DRM, DRM+)==
 
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Under construction
 
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[http://sourceforge.net/apps/mediawiki/drm/index.php?title=Main_Page Dream] open software receiver and transmitter
 
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[http://www.drm-sender.de/ Spark] free DRM/DRM+ transmitter
 
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==DVB-T==
 
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Under construction... (soft DVB ?)
 
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==RDS==
 
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Under construction...
 
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*[https://128.2.212.19/wiki/RDS RDS on gnuradio]
 
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==Other crazy techniques==
 
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Under construction...
 
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Transmission using a VGA card D/A converter as transmitter !
 
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*DVB-T transmission (static signal): http://bellard.org/dvbt/
 
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*Live FM transmitter : http://bk.gnarf.org/creativity/vgasig/
 

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

Retrieved from "https://wiki.opendigitalradio.org/index.php?title=Main_Page&oldid=1578"