dab range what. Authorities launch digital radio in Russia

Hey Geektimes.

Digital broadcasting is gradually being introduced in various countries. In Europe and Australia it is the DAB/DAB+ standard, in the US HD Radio, in China CDR (China Digital Radio). Of the benefits for the user - more clear sound through the digital stream, additional services(e.g. song title and artist name on the receiver screen), and, in the case of DAB, more stations compared to FM. Digital radio capable receivers are already relatively inexpensive, starting at about $40.

Russia has not yet officially joined any of the standards, but if it does, it will most likely be DAB. Its test operation has already been carried out in Moscow, and the receivers of the European market for the Russian Federation are geographically more accessible than the American ones. New European cars (of which, again, there are more than American ones) are often already equipped with a DAB receiver. In the meantime, for test purposes, anyone can run DAB at home, with an SDR transceiver.

(Image Source/Getty)

Details under the cut (careful, a lot of long and boring configs).

How it works

Unfortunately, different standards are incompatible with each other.

European DAB is an MP2 or AAC stream transmitted using ODFM in channels with frequencies from 174 to 239 MHz. More than 30 channels are possible, the width of each is about 1.5 MHz, several stations can be transmitted simultaneously in the channel. According to Wikipedia, using DAB at 192kbps is 3 times more efficient in terms of number of stations than regular FM.

The spectrum of one DAB channel on the SDR screen looks like this:

For comparison, FM stations look like this at the same scale:

in the American HD Radio took a different path - digital channels were added "on the side" to the existing FM stations. This made it possible not to allocate new frequencies and leave compatibility with old receivers. The downside is that in large cities the FM broadcast is already busy. On the other hand, even maximum number 50 stations for FM is quite good, listeners most likely do not need more.

The HD Radio spectrum looks like this (screenshot from youtube):

Chinese CDR decided to copy the American approach, alas, my zero knowledge of Chinese is not enough to find more detailed information on it.

As for the receivers, their price on amazon is from $ 30 for the most simple models, up to >100$ for more advanced ones with touchscreen, Wifi or color screen.

But "the Chukchi is not a reader", so we will launch a test radio in the DAB / DAB + format ourselves. Unfortunately, HD Radio will not be launched, the format is closed, and there are no encoders available for it.

Launching DAB/DAB+

The process is actually not complicated, but very painstaking in terms of creating the necessary configs. For the test, we need Linux and a transferable SDR like HackRF or USRP.

1. Compiling the project

Linux is needed to compile the encoder. I used Ubuntu finished image for VirtualBox was downloaded from http://www.osboxes.org/ubuntu/ .

Compiling ODR-AudioEnc
First you need to compile DAB/DAB+ audio encoder, you can find it at github.com/Opendigitalradio/ODR-AudioEnc .

Git clone https://github.com/Opendigitalradio/ODR-DabMux.git cd ODR-DabMux/ ./bootstrap.sh ./configure make sudo make install
Compiling ODR-DabMod
This is a modulator that actually sends data to the transmitter. The assembly principle is the same, the command for downloading:

Git clone https://github.com/Opendigitalradio/ODR-DabMod.git
If any libraries are missing during the build, they must be installed using apt-get.

Now all the parts of the project are assembled, and with all this we will try to take off.

2. Configuration

Unfortunately, the USRP did not work in the virtual machine, but put full Linux I was too lazy to drive. Therefore, I did not consider the streaming mode - the multiplex was assembled from pre-prepared mp3 files, and the resulting IQ file was launched under Windows. Yes, for the home streaming and it’s not necessary, there was no task to make a “pirate station”.

Data preparation
There will be 2 channels in our multiplex, for which I downloaded 2 mp3 files from youtube and named them (who would have guessed) sound01.mp3 and sound02.mp3 respectively.

Convert files to WAV with a bitrate of 48000:
ffmpeg -i sound01.mp3 -ar 48000 sound01.wav
ffmpeg -i sound02.mp3 -ar 48000 sound02.wav

Convert them to DAB format:
odr-audioenc --dab -b 128 -i sound01.wav -o prog1.mp2
odr-audioenc --dab -b 128 -i sound02.wav -o prog2.mp2

The output should be 2 files prog1.mp2 and prog2.mp2.

Creation of a multiplex

First you need to create a file that describes the configuration of our "radio station". Let me remind you that in one DAB channel there can be many stations, each with its own parameters.

Create a file "config.mux" with the following text:

General ( dabmode 1 nbframes 2000 ; Set to true to enable logging to syslog syslog false ; Enable timestamp definition necessary for SFN ; This also enables time encoding using the MNSC. tist false ) remotecontrol ( telnetport 0 ) ensemble ( id 0x4fff ecc 0xec ; Extended Country Code local-time-offset auto international-table 1 label "mmbtools" shortlabel "mmbtools" ) services ( srv-p1 ( label "Station1" ) srv-p2 ( label "Station2" ) ) subchannels ( sub-p1 ( type audio inputfile "prog1.mp2" bitrate 128 id 10 protection 4 ) sub-p2 ( type audio inputfile "prog2.mp2" bitrate 128 id 11 protection 4 ) ) components ( comp-p1 ( service srv-p1 subchannel sub-p1 ) comp- p2 ( service srv-p2 subchannel sub-p2 ) ) outputs ( output1 "file://output.eti?type=raw" )
The config describes the channels that will be in the multiplex and their data sources. The nbframes parameter specifies how many frames to create, 2000 frames corresponds to approximately one minute of playback.

Once the file is saved, create a multiplex:

odr-dabmux config.mux
The output should be a file output.eti, in my case its size was 12MB.

Broadcast

There are two possibilities here. On "real" Linux, odr-dabmod can directly transfer data to the transceiver, but it did not work under VM. Therefore, as an output parameter, I specified a raw file that will contain data compatible with Gnu Radio.

Create a config.ini file:

transport = file source = output.eti loop=0 digital_gain=0.9 rate=2048000 output = file format = complexf_normalised ;format = s8 filename = output.iq
Here key moment- output format and its type. For USRP, I use the complexf_normalized format, for HackRF, in theory, 8-bit s8 will do.

Save the config, start the conversion:

odr-dabmod config1.ini
Everything! The output should be config.iq, in my case about 700MB in size per minute of recording (IQ float format). We copy it to the "main" computer, and Linux can be closed.

3. Testing

As I said earlier, I don’t have a DAB receiver, the Chukchi is not a reader, I don’t listen to the radio at all :) For testing, I used the RTL-SDR “whistle” and a free program

News about the development of DAB + (Digital Audio Broadcasting) broadcasting in Europe is a little envy. The most "advanced" in this regard were Switzerland, Great Britain and Norway. The latter promises to completely turn off analog FM broadcasting in a few months, replacing it with digital. And even our closest neighbors, the Latvians, decided to start testing the new format for a year before allocating funds for further work. In fairness, it should be noted that Estonia and Lithuania, after conducting a similar study, decided to postpone the transition to digital radio broadcasting.

The layman has a lot of questions: what kind of DAB + format is it, why introduce it and what will it bring to the average listener? Probably, receivers will also have to be bought new: what is known about them and what about the Russian development, or are we again bringing them from abroad? How much will the devices cost?

First steps

Let's start with the background. The transfer of radio broadcasting to digital was originally laid down in the federal target program "Development of television and radio broadcasting in the Russian Federation for 2009-2015", approved in September 2009.

The main goal of the proposed transition is a dramatic improvement in the quality of reception compared to traditional analogue broadcasting in the short wave band.

The FTP focused on the development of broadcasting in the DRM (Digital Radio Mondiale) format. In short, this is a set of technologies using MPEG-IV codecs that allow for digital broadcasting with higher quality in the traditional analog broadcast bands.

All in one

We should also mention a purely Russian development - the RAVIS system, presented in 2005.

RAVIS also allows you to broadcast multimedia services: video, text (information about the state of roads, etc.), static images, etc.

This abbreviation stands for "Russian AudioVisual Information System of Real Time" (it sounds a little different abroad: RAVIS, Real-time AudioVisual Information System). It is intended for broadcasting in the bands 66 - 74 and 87.5 - 108 MHz (what is commonly referred to as the VHF and FM bands). The technology was developed by Viktor Dvorkovich and his son Alexander, specialists in digital video information systems. They subsequently organized the Sad-Com company.

The main advantage of RAVIS is the ability to transmit from 10 to 15 programs with CD-quality stereo sound in one standard radio channel in the indicated ranges. It is no secret that in large cities there is already a problem of frequency distribution for new broadcasters (bands are not unlimited) and this decision would resolve the situation.

And here we turn to one of our first questions: how, in addition to the promised High Quality audio content, this system can "boast" before conventional broadcasting?

The fact that it can also broadcast multimedia services: video, text (information about the state of roads, etc.), static images, etc. According to the idea, all these "benefits" can be received directly in a moving car, on standard whip antennas in urban areas with dense buildings, a multipath signal in the absence of direct visibility of the transmitter antenna, as well as in areas with difficult terrain, in mountainous areas and in dense forests . Of course, the initial resolution for a television mobile television "picture" is small: only 640x480 pixels, but it was assumed that it would be increased to the standard 720x576 pixels. For broadcasters, this solution promises, first of all, a reduction in the power consumption of transmitting devices.

From August 2009 to April 2010, additional improvements and field tests of the RAVIS system model were carried out in Moscow and Sochi. As a result, the national standard was approved - GOST R 54309 - 2011 "Audiovisual Information system real time RAVIS.

Later working group"Space and Telecommunications" of the Commission under the President of the Russian Federation for Modernization and Technological Development recognized the project as promising, but economically poorly developed and recommended for improvements in the Skolkovo Foundation.

On October 16, 2015, at a meeting of the State Commission on Radio Frequencies of the Russian Federation, a decision was made "On the organization of experimental zones of the RAVIS digital broadcasting system".

Here's what it said:

"one. To allocate to the Non-commercial partnership for the support of regional television "Association of Regional Television Companies" and the Moscow Institute of Physics and Technology (MIPT) the radio frequency bands 65.8-74 ​​MHz and 87.5-108 MHz for experimental, experimental and design work of radio broadcasting of the RAVIS system in Kazan , Krasnodar, Izhevsk and Kaliningrad ...

2. The results of experimental, experimental and design work must be submitted by the Non-Commercial Partnership for Regional Television Support "Association of Regional Television Companies" to the SCRF no later than the 4th quarter of 2018."

Well, a little about the receiver this format. Here the results are even more modest than in the case of DRM broadcasting: only approximate cost future models - about 100 - 120 dollars.

Ways of development

So, at the moment there are three main directions in which it was supposed to develop digital broadcasting in our country.

The prospects for DRM in Russia are disappointing. After 2012, events in the bands intended for broadcast in this format developed very quickly and did not better side. In 2014-2015, the main state-owned Russian broadcasters left the ranges of long and medium waves: Radio Russia and Mayak. "Radio Russia" also left short waves.

In 2013, the European Broadcasting Union (EBU) recognized the DAB + standard as the most promising.

As Deputy CEO All-Russian State Television and Radio Broadcasting Company Sergey Arkhipov, the reduction in broadcasting in these bands is associated with a decrease in state funding for All-Russian State Television and Radio Broadcasting Company in 2014.

In fairness, it should be noted that some of the foreign "radio giants" have "cooled" towards the DRM format of broadcasting - first of all, this is the "Deutsche Welle", which long time at the forefront of research in this area. This is due to the general trend of curtailing shortwave and mediumwave broadcasts. Currently, the most active "players" here are Romania and India. About radios of this standard ( Russian production) was already mentioned at the beginning of the material, and since then nothing new has appeared on the market at the moment.

Moreover, in 2013 the European Broadcasting Union (EBU) recognized the DAB + standard as the most promising. It "is robust, has high spectrum efficiency and is economical," according to the materials of the SCRF. DAB+ uses newer codecs and allows you to broadcast up to 16 stations in stereo on a single frequency. He, like the mentioned RAVIS, can diversify the services for the owner of the receiver due to text messages, announcements, etc.

The DAB+ standard is intended for broadcasting in the so-called third radio frequency range - from 174 to 230 MHz. Now in Russia this range is occupied by analog television, but after it is turned off, it should be released (the question is when?).

Receivers with DAB+ are relatively inexpensive, they are produced by several foreign companies (our receivers are not on the market yet).

What's next?

DAB/DAB+ digital radio coverage map in 2014. blue color marked "interested"

As for Russian broadcasting in the DAB+ standard, the situation here is also at the stage of experimental testing. Test broadcast RTRS was conducted from the Ostankino TV tower, the programs of the Mayak radio station were used for broadcasts. In November 2014, at the XVIII International Congress of the National Association of Television and Radio Broadcasting (NAT) during International Exhibition NATEXPO professional equipment at the RTRS booth for the first time in Russia demonstrated the transmission of a radio signal in the DAB + digital standard.

DAB+ is currently broadcast in over 40 countries including Norway, Switzerland, UK, Germany and Denmark.

To do this, the stand was equipped with several radio receivers of various models, which received the signal of a transmitter specially installed on the Ostankino television tower.

Further - information from the protocol of the State Commission for Radio Frequencies under the Ministry of Communications of Russia dated June 30, 2015 "On the results of work in the experimental area of ​​​​experimental digital audio broadcasting of the DAB + standard in the radio frequency band 174-230 MHz":

“Instruct the Federal Agency for Press and mass communications(FSUE RTRS) to continue research within the framework of the research work "Development of recommendations for the implementation in Russian Federation digital standard broadcasting DAB+" regarding the issues of ensuring electromagnetic compatibility with radio-electronic means of various radio services in the range of 174-230 MHz and submit to the State Commission on Radio Frequencies in the fourth quarter of 2015 a draft decision of the State Committee for Radio Frequencies on the use of the radio frequency band 174-230 MHz to create networks in the Russian Federation digital broadcasting DAB standard+».

As you can see from this long excerpt, the State Committee for Radio Frequencies only took note of the report and instructed RTRS to continue work in terms of ensuring electromagnetic compatibility with radio electronic equipment of various radio services. So there is more to come.

DAB+ is currently broadcast in over 40 countries including Norway, Switzerland, UK, Germany and Denmark.

FROM digital television more or less clear. But how does the “digitalization” of radio broadcasting take place? The main and leading standard in the broadcasting industry today is the Digital Audio Broadcasting (DAB) technology, developed in the late 1980s as part of the Eureka 147 project.

When developing this standard persecuted simple goals: improving the quality of radio broadcasts, improving noise immunity, bringing interactivity and new services to the radio. It is important to note that the beginning of work on the DAB standard dates back to 1981, when employees of the Institut für Rundfunktechnik (IRT) worked on this project. Since 1987 the work was transferred to the European research project group (Eureka 147).

DAB technology is standardized by the World DAB Forum, which represents more than thirty countries of the world. Interestingly, the World DAB Forum does not include the United States, since this country was chosen own system digital radio - HD Radio (IBOC).

Many people do not understand what the point of switching to digital radio is, they are satisfied with those radio stations that today broadcast in the AM and FM bands. But maybe we should face the truth? Outside the 21st century, AM technology was introduced to the world in the 1920s, FM in the 1940s. It turns out that today we receive a radio signal using a system developed seventy years ago. So DAB technology offers the oldest broadcast technology to move into the digital age.

Previously, MP2 (MPEG-1 layer-2) audio stream coding system was used for DAB broadcasting. It was developed in the late 1980s, finalized in the early 1990s. The new DAB specification, DAB-2 (DAB+), will use audio stream compression methods such as MPEG 2 Advanced Audio Coding AAC, MPEG 4 Error Resilient BSAC (Bit Slice Arithmetic Coding), MPEG 4 AAC+ SBR, and likely Windows Media audio codecs.

That is, the audio quality, say, 128 kbps, achieved with the help of new audio codecs and the ability to record a signal in AAC format will sound better than an audio stream with the same bitrate, but compressed using the MPEG 2 layer 2 method and the ability to record in MP3 format. Roughly speaking, today the quality of the audio stream when listening to DAB radio corresponds to the quality of an average MP3 file (from 128 to 256 kbps).

Receiving DAB signal

More than 475 million people around the world today have access to over 800 different DAB broadcasts, services and services. There are currently over 200 different DAB receivers available on the market for the consumer and the number continues to grow.

It is worth noting that DAB receivers can be quite confused with radio receivers, which are positioned as "digital", but, in fact, are analog with some additional digital features. For example, the parameter "automatic digital tuner" does not mean at all that the receiver will receive digital signal.

Today there are several types of DAB receivers. First of all, this automotive devices, which, in addition to AM and FM bands, also support digital radio. A lot of manufacturers offer DAB tuners that are compatible with car radios released a few years ago. Other manufacturers produce turnkey DAB solutions that involve complete replacement car audio systems. Major car DAB receiver companies: Alpine, Blaupunkt, Clarion, Goodmans, Grundig, JVC, Kenwood, Ministry of Sound, Pioneer, REVO Digital, Siemens VDO.

In second place are DAB receivers, which are designed for use as part of a home personal computer. When you install such a receiver in your PC, you get the opportunity to listen to digital radio broadcasts on your computer without any additional network or Internet connections. You can also record broadcasts in mp3 format directly to HDD. Similar devices produced by: Modular Technology, Mtech, PersTel, Terratek.

This is followed by home stationary DAB Hi-Fi tuners, which are available in two versions: both built into an existing home audio system, and separate devices. There are options on the market that support only DAB, but if you want, you can also find combined devices (DAB / FM / AM). The first such tuner was released in September 1998. by Arcam. The leading manufacturers of such equipment today are: Acoustic Solutions, Arcam, ARION, BUSH, Cambridge Audio, Cymbol, ELANsat, Eltax, Genus Digital, Goodmans, Grundig, Hitachi, i.Tech Dynamic, Intempo, Kiiro, Maycom, Ministry of Sound, Morthy Richards, Panasonic, PersTel, PURE Digital, Restek, Roberts, Sangean, Sony, TAG McLaren, TEAC, Terratec.

And the last type of DAB receivers is portable portable. The ones we take with us on the road or listen to on the way to work. Commercial portable DAB devices are relatively recent but already available on the market. Today, the main problem of launching such receivers into mass production was their power consumption, which has now been reduced to the level of a conventional CD player. Work to further reduce energy consumption is ongoing. The leading companies in this area are: ARION, BUSH, Grundig, Maycom, Ministry of Sound, Perstel, Philips, Pure Digital. Roberts.

Judging by the number of companies offering various solutions for DAB technology, we can confidently say that DAB has a future, the market is developing, and users are gradually growing interest in a new radio concept. In addition, DAB technology brings a new concept to the provision of radio services. Various additional services and interactive services convert the broadcast format itself. Among similar services you can note:

• broadcasting as such (primary service);
• Additional Information;
• transfer of information (for example, downloading a song that is currently playing on the radio to a DAB receiver);
• electronic program guide (EPG);
• slideshows synchronized with the audio broadcast;
• video;
• Java applications.

Most of the countries in the world considering the transition from analogue to digital broadcasting have opted for the DAB standard. Real DAB services already operate in most of Europe, Canada, Taiwan and South Korea. Test launches are taking place in China, South Africa and Turkey. There is a growing interest in technology in Russia, South and Latin America, in the countries of the Middle East and Southeast Asia. The US has developed and preferred its own digital radio standard, HD Radio.

In Russia today there is not a single T-DAB transmitter. However, issues related to the issuance of licenses for broadcasting in the DAB format are already being actively discussed. The main problem, due to which the introduction of this standard on the territory of Russia is postponed indefinitely, is the mandatory replacement of existing radios, receivers and tuners with new, digital ones.

Until a rather cheap and high-quality product of this kind appears on the market, one can only dream of spreading DAB radio in our country. After all, most Russians today are quite satisfied with the quality of FM radio stations.

We dreamed so much about replacing numbers about and analog technologies in the 80s and 90s, which they did not notice, as in many directions they reached the final stage of this process. This stage is called analog switchoff - that is, literally, “switching off anal about ha. It comes when the digital version of a particular technology, product, process, pulls over the dominant number of users - and the decision is made to turn off the analog version.

The solution can be either market-driven (as with audio records that have ceased to be produced due to lack of demand) or top-down (as with television, which is gradually being replaced by digital). But anyway last years showed that immediately after this, unexpected strengths anal about ha, which I would not like to lose. That is, it’s kind of embarrassing to return, and it’s completely wrong to turn away!

We have already seen how this happens with music and sound in general, books, newspapers and magazines (remember ""). Now we have to experience the same thing with the radio. Not immediately, however, and not soon, but - the process of disconnection has begun. Norway was the first to decide on it, which by the end of the year intends to forcibly switch all state radio channels to digital broadcasting, while turning off FM at the same time. Following it, Switzerland, Great Britain, Denmark and some others follow the same course. And it is worth watching this process at least in order not to step on the discovered rake later.

The analog radio has been an almost eternal thing: even models released half a century ago can still be used today. Digital receivers will not live that long for sure! Changing standards will probably force them to be updated as often as we update mobile phones today.

Norway is starting a scheduled shutdown of state-owned FM stations as of this week. Within a year they will stop broadcasting in FM format and will be transferred to DAB. What is FM - everyone knows. This term simultaneously understands both the range (VHF: 88 - 108 MHz in the West, or down to 65 MHz in the social block) and the modulation method (frequency). Throughout the second half of the 20th century, FM was synonymous with quality sound: frequency modulation in combination with an ultrashort wavelength, they make it possible to transmit a stereo signal and place dozens of stations in the range. FM has disadvantages, for example, a small range (compared to MW and HF; FM is heard only a little further than the line of sight), but this did not prevent it from becoming the de facto standard for music broadcasting in cities.

And now the change is coming. DAB (from digital audio broadcasting - digital audio broadcasting) is a relatively new thing: public experiments with it began only in the second half of the 90s. Meaning: broadcasting digital, not analog signal, at 128 kbps, in the band just above FM, using noise-correcting coding and the popular MP2 compressor in the past. The receiver, accordingly, is needed digital, that is, it will have to be bought new, but this promises serious benefits. In general, the benefits of transferring radio to a digital standard are circular: absolutely everything wins!

Firstly, DAB is beneficial to broadcasting regulators: they will be able to sell more licenses and fit more stations in the band (the digital signal is less susceptible to distortion from neighboring frequencies).

Secondly, DAB is beneficial for radio station holders, because it allows you to load the transmitter many times more efficiently, and also to conduct encrypted broadcasts that are available only for a fee.

Third, DAB benefits listeners. Unlike analogue broadcasting, the quality of which decreases continuously as it moves away from the station, the quality of digital broadcasting is consistently high - up to a certain critical distance, after which the power of the received signal drops below the permissible level and reception stops, or there are too many errors.

That's the theory. And tell someone this fifteen years ago, when the fashion for replacing anal was raging about ha figure, no one would doubt the veracity of these words. Today, however, already about half of the radio listeners in the countries mentioned above use DAB on a daily basis. And the reviews ... so-so! Why? Several reasons are cited.

Looking ahead: DAB is already obsolete and should be replaced by more modern standard. But worse than that, different countries being introduced different variants digital radio. In Russia, for example, approved as a priority international standard DRM.

First, it turned out that the noise immunity of digital radio transmission is greatly exaggerated. No one even remembers that such a signal cannot be received even at a small distance from cities: the reception radius digital stations always less than for FM. But even in cities and on major roads, due to difficult terrain and distances, there are areas where the DAB signal weakens below acceptable levels. And then the figure manifests itself with worst side: the sound either disappears altogether, or turns into a meaningless gurgling - while an FM station would be heard, albeit with interference, but legibly! It is also worth adding here that the digital receiver is much more complicated and expensive, and is also naughty when moving with high speed: already moving faster than 120 km / h, it reduces the reception quality.

Secondly, it suddenly surfaced that DAB is an outdated standard. It is customary to encode sound using MP2, which (at the used transmission speeds) does not give a sound quality close to CD or even FM! When the DAB experiments were just starting, it didn't matter, but today, when it comes to turning off FM completely, the situation appears in a different light. There is a solution: the DAB + standard uses a modern codec from the MPEG-4 family, only old DAB receivers are incompatible with it! And this has brought suspicions of foul play among DAB supporters: what if the replacement of FM with DAB is intended only so that corporations will profit from the sale of new receivers, and then profit every year from upgrades?

Finally, thirdly, many people doubt the declared readiness of DAB stations for emergencies. After all, state radio stations are used, among other things, for transmitting signals to alert the population about emergencies. But if FM could be accepted by everyone, then DAB in the same Norway - God forbid that every second resident (the rest simply do not digital receivers). And digital communications have the famous property of “falling” first in natural disasters and catastrophes. Will it happen again with DAB?

As a result, the question of the reasonableness of turning off FM no longer seems idle. Will digital radio ever replace analog radio? Or will it remain only an optional addition to the ancient, but by no means obsolete technology? What do you think?

News about the development of DAB + (Digital Audio Broadcasting) broadcasting in Europe is a little envy. The most "advanced" in this regard were Switzerland, Great Britain and Norway. The latter promises to completely turn off analog FM broadcasting in a few months, replacing it with digital. And even our closest neighbors, the Latvians, decided to start testing the new format for a year before allocating funds for further work. In fairness, it should be noted that Estonia and Lithuania, having conducted a similar study, decided to postpone the transition to digital broadcasting for the time being.

The layman has a lot of questions: what kind of DAB + format is it, why introduce it and what will it bring to the average listener? Probably, receivers will also have to be bought new: what is known about them and what about the Russian development, or are we again bringing them from abroad? How much will the devices cost?

First steps

Let's start with the background. The transfer of radio broadcasting to digital was originally laid down in the federal target program "Development of television and radio broadcasting in the Russian Federation for 2009-2015", approved in September 2009.

The main goal of the proposed transition is a dramatic improvement in the quality of reception compared to traditional analogue broadcasting in the short wave band.

The FTP focused on the development of broadcasting in the DRM (Digital Radio Mondiale) format. In short, this is a set of technologies using MPEG-IV codecs that allow for digital broadcasting with higher quality in the traditional analog broadcast bands.

All in one

We should also mention a purely Russian development - the RAVIS system, presented in 2005.

RAVIS also allows you to broadcast multimedia services: video, text (information about the state of roads, etc.), static images, etc.

This abbreviation stands for "Russian AudioVisual Information System of Real Time" (it sounds a little different abroad: RAVIS, Real-time AudioVisual Information System). It is intended for broadcasting in the bands 66 - 74 and 87.5 - 108 MHz (what is commonly referred to as the VHF and FM bands). The technology was developed by Viktor Dvorkovich and his son Alexander, specialists in digital video information systems. They subsequently organized the Sad-Com company.

The main advantage of RAVIS is the ability to transmit from 10 to 15 programs with CD-quality stereo sound in one standard radio channel in the indicated ranges. It's no secret that in large cities there is already a problem of frequency distribution for new broadcasters (bands are not unlimited) and this solution would help to resolve the situation.

And here we turn to one of our first questions: what, in addition to the promised high quality of audio content, can this system “boast” of in front of conventional broadcasting?

The fact that it can also broadcast multimedia services: video, text (information about the state of roads, etc.), static images, etc. According to the idea, all these "benefits" can be received directly in a moving car, on standard whip antennas in urban areas with dense buildings, a multipath signal in the absence of direct visibility of the transmitter antenna, as well as in areas with difficult terrain, in mountainous areas and in dense forests . Of course, the initial resolution for a television mobile television "picture" is small: only 640x480 pixels, but it was assumed that it would be increased to the standard 720x576 pixels. For broadcasters, this solution promises, first of all, a reduction in the power consumption of transmitting devices.

From August 2009 to April 2010, additional improvements and field tests of the RAVIS system model were carried out in Moscow and Sochi. As a result, the national standard was approved - GOST R 54309 - 2011 "Audiovisual information system of real time RAVIS".

Later, the working group "Space and Telecommunications" of the Commission under the President of the Russian Federation for Modernization and Technological Development recognized the project as promising, but economically poorly developed and recommended for improvements in the Skolkovo Foundation.

On October 16, 2015, at a meeting of the State Commission on Radio Frequencies of the Russian Federation, a decision was made "On the organization of experimental zones of the RAVIS digital broadcasting system".

Here's what it said:

"one. To allocate to the Non-commercial partnership for the support of regional television "Association of Regional Television Companies" and the Moscow Institute of Physics and Technology (MIPT) the radio frequency bands 65.8-74 ​​MHz and 87.5-108 MHz for experimental, experimental and design work of radio broadcasting of the RAVIS system in Kazan , Krasnodar, Izhevsk and Kaliningrad ...

2. The results of experimental, experimental and design work must be submitted by the Non-Commercial Partnership for Regional Television Support "Association of Regional Television Companies" to the SCRF no later than the 4th quarter of 2018."

Well, a little about the receiver of this format. Here the results are even more modest than in the case of DRM broadcasting: only the approximate cost of future models is known - about 100 - 120 dollars.

Ways of development

So, at the moment there are three main directions in which it was supposed to develop digital broadcasting in our country.

The prospects for DRM in Russia are disappointing. After 2012, events in the bands intended for broadcasts in this format developed very quickly and not for the better. In 2014-2015, the main state-owned Russian broadcasters left the ranges of long and medium waves: Radio Russia and Mayak. "Radio Russia" also left short waves.

In 2013, the European Broadcasting Union (EBU) recognized the DAB + standard as the most promising.

As Deputy Director General of the All-Russian State Television and Radio Broadcasting Company Sergey Arkhipov stated, the reduction in broadcasting in these bands is associated with a decrease in state funding for the All-Russian State Television and Radio Broadcasting Company in 2014.

In fairness, it should be noted that some of the foreign "radio giants" have "cooled off" towards the DRM format of broadcasting - first of all, this is the "Deutsche Welle", which has been at the forefront of research in this area for a long time. This is due to the general trend of curtailing shortwave and mediumwave broadcasts. Currently, the most active "players" here are Romania and India. Radio receivers of this standard (Russian-made) were already mentioned at the beginning of the material, and since then nothing new has appeared on the market at the moment.

Moreover, in 2013 the European Broadcasting Union (EBU) recognized the DAB + standard as the most promising. It "is robust, has high spectrum efficiency and is economical," according to the materials of the SCRF. DAB+ uses newer codecs and allows you to broadcast up to 16 stations in stereo on a single frequency. He, like the mentioned RAVIS, can diversify the services for the owner of the receiver through text messages, announcements, etc.

The DAB+ standard is intended for broadcasting in the so-called third radio frequency range - from 174 to 230 MHz. Now in Russia this range is occupied by analog television, but after it is turned off, it should be released (the question is when?).

Receivers with DAB+ are relatively inexpensive, they are produced by several foreign companies (our receivers are not on the market yet).

What's next?

DAB/DAB+ digital radio coverage map in 2014. “Interested” are marked in blue

As for Russian broadcasting in the DAB+ standard, the situation here is also at the stage of experimental testing. Test broadcasting was carried out by RTRS from the Ostankino TV tower, the programs of the Mayak radio station were used for transmissions. In November 2014, at the XVIII International Congress of the National Association of Television and Radio Broadcasting (NAT) during the International Exhibition of Professional Equipment NATEXPO at the RTRS booth, for the first time in Russia, a demonstration of radio signal transmission in the DAB + digital standard was held.

DAB+ is currently broadcast in over 40 countries including Norway, Switzerland, UK, Germany and Denmark.

To do this, the stand was equipped with several radio receivers of various models, which received the signal of a transmitter specially installed on the Ostankino television tower.

Further - information from the protocol of the State Commission for Radio Frequencies under the Ministry of Communications of Russia dated June 30, 2015 "On the results of work in the experimental area of ​​​​experimental digital audio broadcasting of the DAB + standard in the radio frequency band 174-230 MHz":

“To instruct the Federal Agency for Press and Mass Communications (FSUE RTRS) to continue research within the framework of the research work “Development of recommendations for the implementation of the DAB + digital broadcasting standard in the Russian Federation” regarding the issues of ensuring electromagnetic compatibility with radio-electronic means of various radio services in the range 174-230 MHz and submit to the State Commission for Radio Frequencies in the fourth quarter of 2015 a draft decision of the State Committee for Radio Frequencies on the use of the radio frequency band 174-230 MHz to create digital broadcasting networks of the DAB + standard in the Russian Federation.

As you can see from this long excerpt, the State Committee for Radio Frequencies only took note of the report and instructed RTRS to continue work in terms of ensuring electromagnetic compatibility with radio electronic equipment of various radio services. So there is more to come.

DAB+ is currently broadcast in over 40 countries including Norway, Switzerland, UK, Germany and Denmark.