Formats of the future: how Russian digital radio broadcasting will develop. Authorities launch digital radio in Russia

News about the development of radio broadcasting in the DAB+ (Digital Audio Broadcasting) format in Europe causes slight envy. The most “advanced” in this regard were Switzerland, Great Britain and Norway. The latter promises to completely turn off analogue FM broadcasting in a few months, replacing it with digital one. And even our closest neighbors, the Latvians, decided to begin annual testing of the new format before allocating funds for further work. To be fair, it should be noted that Estonia and Lithuania, after conducting a similar study, decided to postpone the transition to digital broadcasting for now.

The average person has a lot of questions: what kind of DAB+ format is this, why implement it, and what will it bring to the average listener? Probably, we will have to buy new receivers: what is known about them and what about Russian developments, or are we importing them from abroad again? How much will the devices cost?

First steps

Let's start with the background. The transfer of radio broadcasting to digital was initially included 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 was a dramatic improvement in the quality of reception compared to traditional analogue radio broadcasting in the short wave range.

The Federal Target Program focused on the development of radio broadcasting in the DRM (Digital Radio Mondiale) format. In short, this is a set of technologies using MPEG-IV codecs, which make it possible to provide digital broadcasting with higher quality in the ranges traditional for analogue broadcasts.

All in one

It is worth mentioning a purely Russian development - the RAVIS system, presented in 2005.

RAVIS allows you to broadcast multimedia services: video, text (information about road conditions, etc.), static images, etc.

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 specified 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 move on to one of our first questions: what, in addition to what was promised? high quality audio content, can this system “boast” compared to conventional broadcasting?

One that can also broadcast multimedia services: video, text (information about road conditions, etc.), static images, etc. According to the idea, all these “benefits” can be received directly in a moving car, using standard whip antennas in urban environments with dense buildings, a multi-beam 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, the “Space and Telecommunications” working group of the Russian Presidential Commission for Modernization and Technological Development recognized the project as promising, but economically poorly developed and recommended it for improvements at 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.”

This is what it prescribed:

"1. Allocate the radio frequency bands 65.8-74 ​​MHz and 87.5-108 MHz to the Non-Profit Partnership for the Support of Regional Television "Association of Regional Television Companies" and the Moscow Institute of Physics and Technology (MIPT) for carrying out experimental, experimental and design work on radio broadcasting of the RAVIS system in Kazan , Krasnodar, Izhevsk and Kaliningrad...

2. The results of experimental, experimental and design work must be presented Non-profit partnership support for regional television "Association of Regional Television Companies" in SCRF no later than the fourth 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 along which it was planned to develop digital radio 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. The main state Russian broadcasters: Radio Russia and Mayak left the long and medium wave bands in 2014 - 2015. Radio Russia also left short waves.

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

To be fair, it should be noted that some foreign “radio giants” have also cooled off towards the DRM broadcast format - first of all, 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 short-wave and medium-wave broadcasts. Currently, the most active “players” here are Romania and India. Radio receivers of this standard (Russian production) 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 distinguished by its stability, high spectrum efficiency and cost-effectiveness,” according to SCRF materials. DAB+ uses newer codecs and allows up to 16 stations to be broadcast in stereo on one frequency. It, like the mentioned RAVIS, can diversify services for the owner of the receiver due to text messages, advertisements, etc.

The DAB+ standard is designed for broadcasting in the so-called third radio frequency range - from 174 to 230 MHz. Now in Russia this range is occupied analogue television, but after turning it off it should be freed (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

Regarding Russian radio broadcasting in the DAB+ standard, then here too the situation is in the experimental testing stage. Test broadcasting was carried out by RTRS from the Ostankino TV tower; programs from the Mayak radio station were used for broadcasts. In November 2014, at the XVIII International Congress of the National Association of Broadcasting (NAT) during the International Exhibition professional equipment NATEXPO demonstrated radio signal transmission in the DAB+ digital standard for the first time in Russia at the RTRS stand.

DAB+ radio is currently broadcast in more than 40 countries, including Norway, Switzerland, the UK, Germany and Denmark.

For this purpose, the stand was equipped with several radio receivers. various models, which received the signal from a transmitter specially installed on the Ostankino TV tower.

Below is information from the protocol of the State Commission on Radio Frequencies under the Ministry of Telecom and Mass Communications of Russia dated June 30, 2015 “On the results of work in the experimental zone 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 implementation in Russian Federation digital broadcasting standard DAB+" regarding issues of ensuring electromagnetic compatibility with radio electronic equipment of various radio services in the range of 174-230 MHz and submit in the fourth quarter of 2015 to the State Commission on Radio Frequencies a draft decision of the SCRF on the use of the radio frequency band 174-230 MHz for the creation of digital radio broadcasting networks of the DAB+ standard on the territory of the Russian Federation.”

As we see from this long excerpt, SCRF 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's still more to come.

DAB+ radio is currently broadcast in more than 40 countries, including Norway, Switzerland, the UK, Germany and Denmark.

07/20/2015, Mon, 18:07, Moscow time, Text: Igor Korolev

Having never launched digital radio broadcasting, the Russian authorities are ready to change its format. Instead of the previously planned DRM standard, it is proposed to return to the DAB standard, but in a more modern modification - DAB+.

Constantly changing standards

CNews has obtained Moskovsky's report state university communications and computer science regarding the results of testing the DAB+ digital broadcasting standard. Testing was carried out by the federal state enterprise "Russian Television and broadcast network"(RTRS) in relation to the permit issued last year by the State Commission on Radio Frequencies (SCRF).

They started thinking about the digitalization of radio broadcasting in Russia simultaneously with the digitalization of television broadcasting - in the late 1990s. Then the State Communications Committee was going to use the European standard DAB (Digital Audio Broadcasting), intended for ultrashort waves (VHF), for digital radio broadcasting. By 2010, it was planned to cover the entire country with DAB broadcasting, but work in this area was never carried out.

The Federal Program for Digitalization of TV and Radio Broadcasting was adopted only in 2009, and by that time it was possible to use another digital radio standard - DRM (Digital Radio Mondiale), intended for long, medium and short waves.

However, no work has been carried out in the area of ​​DRM implementation either. Now RTRS proposes to return to the DAB standard, but in its more modern modification – DAB+. The DAB/DAB+ standards are intended for broadcasting in the so-called third radio frequency range – 174 – 230 MHz. Now in Russia this range is occupied by television, but after analogue TV broadcasting is turned off, it should become free.

The DAB+ standard differs from DAB by using a more modern audio codec - HE-ACC v2 instead of MPEG 1 layer 2, which improves broadcast quality and improves error correction. DAB+ allows you to broadcast up to 16 radio stations on one frequency in stereo quality (the DAB standard allows you to broadcast up to 10 radio stations on one frequency).

Currently, the DAB/DAB+ standard has been implemented in 21 countries: mainly European countries, as well as Hong Kong, South Korea and Australia. Another 15 countries are testing this standard. At the end of 2014, subscribers had 89 million DAB/DAB+ digital radios; their number quadrupled over the year.

Signal testing

Testing of DAB+ broadcasting was carried out by RTRS in Moscow from the Ostankino TV tower; broadcasting from Mayak radio was used for the test. Checking the signal over several walking routes- in the Khoroshevo-Mnevniki and Kuntsevo and Tagansky districts - showed enough confident reception with the exception of a few areas.

The reception inside residential buildings was also strong. But inside the stores located in these areas - “Pyaterochka”, “Dixie”, “Sportmaster”, “Rainbow”, “Seventh Continent” and others, the signal could only be picked up next to the windows. In semi-basement fairs and shops, as well as in pedestrian crossings, there was no signal reception at all.

Testing in cars on the section of the Moscow Ring Road from Crocus Expo to Novorizhskoe Highway showed that signal reception was carried out with varying success. Outside the Moscow Ring Road - in the village of Putilkovo, Krasnogorsk district of the Moscow region - signal reception was possible only in areas of low-rise buildings. There was no reception in urban areas, including inside shops and shopping centers.

Comparison of DAB+ with other standards

After processing the test results, it was found that to ensure comfortable reception of DAB/DAB+ signals in a car (in broadcast mode up to 16 stereo-quality radio programs), the intensity indicator is 63 dBµV/m for a metropolis and 49 dBµV/m for rural areas. For comfortable reception inside buildings, these indicators should be 74 dBµV/m and 54 dBµV/m, respectively.

Previous studies have established that when broadcasting a DRM standard signal (one radio program in stereo quality), the field strength indicator is 72 dBµV/m in metropolitan conditions (provides reception in 50% of buildings) and 34 dBµV/m for rural areas.

For analog VHF broadcasting (one radio program in mono quality), the field strength is 70 dBµV/m for metropolitan areas and 48 dBµV/m for rural areas. Provided that one radio program is broadcast in stereo quality, these figures are 74 dBµV/m and 54 dBµV/m, respectively.

Thus, for broadcasting in rural areas, the least transmitter power required is for the DRM standard. In megacities, the power requirements for DAB/DAB+ transmitters are similar to those for DRM and analogue broadcasting transmitters. But a strong advantage of DAB+ is the ability to broadcast 16 radio stations at once on the same frequency.

Economic feasibility

The cost of a transmitter for DAB+ with a power of 2.5 kW is $120 thousand. The rest of the equipment necessary to start broadcasting - a DAB multiplexer, a DAB+ encoder, a modulator, a 250 W power amplifier, a channel filter, antennas - will cost a total of $50 thousand.

To organize analogue broadcasting, you will need a transmitter costing $50 thousand (with a power of 10 kW). It's cheaper than a DAB+ transmitter. However, if we take into account that one DAB+ transmitter transmits up to 16 radio stations, then from an economic point of view, organizing digital broadcasting DAB+ is more profitable than analogue broadcasting from scratch.

If analogue broadcasting has already been deployed, then switching to DAB+ will only save on energy costs. The approximate savings will be 1.375 million rubles. per year, that is, the cost of the transmitter alone will pay off in only four years.

But in the case of the release of the third band from analogue television broadcasting, it is possible to use the transmitter and antenna that RTRS already has. Then the cost of the remaining equipment necessary to launch broadcasting in the DAB+ standard will be 30 thousand euros, and by reducing energy costs it can be repaid in just 1.5 years.

Criticism of the standard

In the draft decision of the SCRF (available to CNews), it was assumed, based on the results of the consideration this report, allocate the frequency band 174 – 320 MHz for radio broadcasting in the DAB+ standard. However, the final decision of the commission states that SCRF only took note of the report and instructed RTRS to continue work in this area. RTRS does not comment on the progress of consideration of the issue of DAB+.

Hello Geektimes.

Digital radio broadcasting is gradually being introduced in various countries. In Europe and Australia this is the DAB/DAB+ standard, in the USA HD Radio, in China CDR (China Digital Radio). The advantages for the user are cleaner sound due to the digital stream, additional services(eg song title and artist name on the receiver screen), and, in the case of DAB, larger number stations compared to FM. Receivers that support digital radio are already relatively inexpensive, starting at around $40.

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

(Image Source/Getty)

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

How does this work

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

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

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

In American HD Radio took a different path - digital channels added “to the side” to the existing FM stations. This made it possible not to allocate new frequencies and maintain compatibility with old receivers. The downside is that in large cities the FM airwaves are already busy. On the other hand, even the maximum number of 50 stations for FM is quite good; listeners most likely don’t need more.

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

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

As for receivers, their price on Amazon ranges from $30 for the simplest models, to >100$ for more advanced ones with a touchscreen, Wifi or color screen.

But “the Chukchi is not a reader,” so we will launch a test radio in DAB/DAB+ format ourselves. Unfortunately, it won’t be possible to launch HD Radio, the format is closed, and there are no available encoders for it.

Launch DAB/DAB+

1. Compiling the project

Compiling ODR-AudioEnc
First you need to compile the 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 is:

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

Now all the parts of the project have been collected, and with all this we will try to take off.

2. Configuration

Data preparation
Our multiplex will have 2 channels, 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

Let's 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 we need to create a file describing the configuration of our “radio station”. Let me remind you that one DAB channel can contain 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.

When 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. In “real” Linux, odr-dabmod can directly transmit data to the transceiver, but it did not work under VM. Therefore, I specified a raw file as the output parameter, which will contain data compatible with Gnu Radio.

Create the 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
The key point here is the output format and its type. For USRP I use the complexf_normalised format; for HackRF, in theory, 8-bit s8 is suitable.

Save the config and start the conversion:

Odr-dabmod config1.ini
All! The output should be config.iq, in my case about 700MB in size for one minute of recording (IQ float format). We copy it to the “main” computer, and Linux can be closed.

3. Testing

Digital Audio Broadcasting (DAB) is a technology that allows broadcasting digital radio programs. DAB technology is used in 21 countries, mainly in Europe. In Russia, radio using this technology is only planned for use in 2019-2020.

Digital audio broadcasting is guaranteed to be different from analogue FM radio. It also allows for more efficient use of available frequencies. Digitization reduces the cost of radio broadcasting because fewer transmitters are used.

DAB and DAB+ standards

The first DAB transmitters used the MP2 codec (MPEG Audio Layer II), after some time it was decided to switch to the HE-AAC v2 codec. Thus the DAB+ format was born. DAB radios are not compatible with the newer audio compression standard, but DAB+ radios are compatible with both codecs. DAB+ also adds an implementation of Reed-Solomon correction coding, which eliminates transmission errors. Some DAB radios can be adapted to receive DAB+ by updating their software and are marked as being updated.

The HE-AAC v2 codec used in DAB provides better audio quality than other solutions used for efficient broadcast compression. Using this codec, ideal reproduction of the original is obtained at 300 Kbps. An analogue of traditional FM broadcasting is the bit rate of 160-192 kbit/s. Even at 128 Kbps, the sound is close to the original. Broadcasters vary bit rates depending on the station's profile. For example, programs intended for listeners with special requests have the bitrate set at 128 kbit/s, for popular programs 112 kbit/s is set, and, for example, 64 kbit/s can be used for the information flow. When reading these values, please be aware that stated figures may not always correspond bandwidth audio. For example, if a station advertises the bit rate at maximum level in DAB+ (192 kbit/s), this means that the audio bit rate is no more than 175 kbit/s, and it can be even lower if the station attaches so-called accompanying data.

DAB frequencies

In accordance with the Special Agreement in Wiesbaden in 1995, frequencies in the range 174-230 MHz were allocated for digital radio in Europe. In a number of countries (including Norway), digital radio also occupies frequencies of 230-240 MHz. European broadcasters may also be granted the right to use parts of the L-band (1452-1492 MHz), but this is rarely practiced.

History of digital radio development

Professional DAB receivers were released as early as the mid-90s, while consumer models appeared on the market in the summer of 1998. Home radio stations in updated version(DAB+) were sold at the end of 2007. In 2016, the first smartphone to support DAB+ appeared: the LG Stylus.

Digital Audio Broadcasting technology has not replaced analog FM broadcasts. Although it is available in an area of ​​over half a billion people, the number of DAB/DAB+ radios purchased is estimated at over 30 million (2014 data). However, significant progress has been made in Europe in building DAB+ infrastructure, so several countries have developed plans to phase out analogue radio. Norway is due to phase out analogue FM transmitters in 2018, Switzerland could phase out in 2020-2024, and Sweden in 2022 or 2024. Car manufacturers can help promote digital terrestrial radio, with some offering DAB/DAB+ radios as standard or as an option. Unlike the digitization of television, the European Union has not required member states to switch off the analogue signal, but there may be an EU decision regarding the digitization of radios in the future - in 2015 it sought support from the European WorldDMB commission promoting the introduction of DAB/DAB+ .

In addition to DAB+, there are other digital technologies that broadcasters are interested in, such as radio broadcasts included in digital television packages ( terrestrial DVB-T, satellite DVB-S and cable DVB-C). Internet radio is also developing dynamically. In some countries, in addition to DAB+ partially complying with the DMB standard (which additionally allows video material to be emitted), DAB+ DVB-H, DVB-SH and DRM+ standards have also been fully developed.

Criticism of the system

Although the HE-AAC v2 codec used in DAB+ provides better audio quality than other solutions used to efficiently compress broadcast material, many broadcasters broadcast their programs at lower than recommended bitrates. For example, the German Radio Horeb transmits at 48 kbit/s, and some music programs(including BBC Asian Network) are broadcast in the UK at 64 kbit/s mp2, which corresponds to approximately 50 kbit/s in the mp3 standard. This number means seven times slower data transfer speed than broadcast best quality, available on the sender's website, having a quality of 360 kbit/s. Additionally, unlike FM station programs, which can be noisy and interfere with the reception signal, loss of the digital radio signal will cause reception to be completely interrupted. Motion-related glitches are also more common than in FM.

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

When developing this standard, simple goals were pursued: improving the quality of radio broadcasts, improving noise immunity, introducing interactivity and new services into radio. It is important to note that the start 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).

The standardization of DAB technology is carried out by the World DAB Forum, which represents more than thirty countries around the world. It is interesting that the World DAB Forum does not include the USA, since this country was chosen own system digital radio – HD Radio (IBOC).

Many people do not understand the point of switching to digital radio; they are also satisfied with those radio stations that today broadcast in the AM and FM bands. But maybe we should face the truth? It's 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 a move into the digital age.

Previously, DAB broadcasting used the MP2 audio stream encoding system (MPEG-1 layer-2). It was developed in the late 1980s and refined in the early 1990s. The new DAB specification, DAB-2 (DAB+), will use audio 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 WindowsMedia audio codecs.

That is, the audio quality, say, 128 kbit/s, achieved using new audio codecs and the ability to record the signal in the 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 the average MP3 file (from 128 to 256 kbps).

We receive a DAB signal

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

It is worth noting that DAB receivers can be completely confused with radio receivers, which are positioned as “digital”, but, in fact, are analogue with some additional digital features. For example, the "automatic" option digital tuner"does not mean that the receiver will receive a digital signal.

Today there are several types of DAB receivers. First of all this automotive devices, which, in addition to the AM and FM bands, also support digital radio. Many manufacturers offer DAB tuners that are compatible with car radios that were released several years ago. Other manufacturers produce completely ready-made DAB solutions that require complete replacement car audio systems. The main companies producing car DAB receivers: Alpine, Blaupunkt, Clarion, Goodmans, Grundig, JVC, Kenwood, Ministry of Sound, Pioneer, REVO Digital, Siemens VDO.

In second place are DAB receivers, which are intended for use as part of a home personal computer. When you install such a receiver in a 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 hard drive. Similar devices are produced by: Modular Technology, Mtech, PersTel, Terratek.

Next come home stationary DAB Hi-Fi tuners, which are available in two versions: both built into an existing audio system at home, and separate devices. There are options on the market that only support DAB, but if you wish, 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. Those that we take with us on the road or listen to on the way to work. Commercial portable DAB devices have only recently emerged but are already available on the market. Today, the main problem with 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 currently underway. 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’ interest in new concept radio. In addition, DAB technology brings something new to the concept of radio services. Various additional services and interactive services are transforming the broadcast format itself. Among such services are:

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

Most countries in the world that were thinking about switching from analogue to digital radio broadcasting preferred the DAB standard. Real DAB services are already available in most of Europe, Canada, Taiwan and South Korea. Test launches are taking place in China, South Africa and Turkey. Interest in technology is growing in Russia, South and Latin America, the Middle East and Southeast Asia. The United States has developed and preferred its own digital broadcasting 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 implementation of this standard in Russia is being postponed indefinitely is the mandatory replacement of existing radios, receivers and tuners with new, digital ones.

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