What is dab in a radio? The Ministry of Telecom and Mass Communications fears that digitalization will destroy the radio broadcasting market

What Norway did

Earlier this year, Norway began switching national radio stations from FM frequencies to digital broadcasting in the DAB format. The experiment began in January in the Nordland region and ended on December 13 in the northern regions of Troms and Finnmark. Norway became the first country in the world to abandon analogue radio throughout its territory. This does not mean that FM radio is no longer used in the country: only national radio stations - for example, NRK - have moved to the new format. Private and small stations will continue to broadcast on FM frequencies until 2022, after which their licenses will be reviewed.

Why Norwegian Radio is Moving

Norway has long begun experimenting with digital radio - the first such station launched in 1995. By 2017, there are 31 national digital stations operating in the country. By comparison, there were only five national FM stations in the country. Digital broadcasting in mountainous areas that distort FM signals. It will cost the government eight times less than analog and will save about 20 million euros annually. However, the majority of Norwegians - 66% -: they complain about insufficient coverage in mountainous regions and poor sound quality, and fishermen are afraid that digital radio. But by December, 86% of all radio listeners in Norway were already .

How is digital radio different from analog?

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Tivoli Audio Music System+

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Denver DAB-40 Gray

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At FM frequencies, a station transmits a radio signal and modulates it so that it turns into voice or music. DAB (Digital Audio Broadcasting) digital radio also uses radio frequencies, but it encodes the signal and transmits it in parts, and then the receiver decrypts this signal. FM radio operates in frequencies from 87.5 to 108 megahertz (in different countries range is different), digital radio will operate in other frequencies - from 174 to 240 megahertz. For example, the Norwegian radio NRK P1, which in Oslo operated on a frequency of 88.7 megahertz, moved to a frequency of 227.36 megahertz.

What are the advantages of digital radio?

Reception quality

There should be no wheezing or hissing on digital radio stations. They have an important difference from FM radio: they either sound good or don't work at all. The quality of FM radio reception depends on the strength of the signal: if the signal is weak, you may be able to pick up the station, but with some wheezing. But digital radio has a critical point: if the signal strength exceeds it, then the station sounds good, if the signal strength drops below, then the station cannot be heard at all.

New stations

To prevent signals from FM radio stations from interfering with each other, a little space is left between their frequencies, for example, the frequencies of radio stations in Moscow go in increments of 0.4 megahertz: 100.1, 100.5, 100.9, and so on. Digital radio stations encrypt their signals and do not interfere with each other, so three times as many stations can be launched on the same band. There are 52 stations in Moscow; if radio broadcasting in Russia is switched to digital, there will be more than 150 stations in the city.

New formats

Digital radio will provide new ways to earn money. For example, broadcasters will be able to encrypt the signal so that it is only accessible paid subscribers. Along with the sound, digital stations transmit meta-information, such as song titles, short news items and program announcements. This text will appear on the receiver screen. If your digital radio receiver has a built-in storage device, it will be able to record programs into memory and rewind programs to the beginning. Thus, radio programs will turn into podcasts that can be listened to several times.

What are the disadvantages of digital radio?

Sound quality

DAB is not a new format, it was developed in the 1980s. It uses the MPEG-1 Audio Layer II compression format, so the audio quality of digital radio is not very high: stations broadcast at a bitrate of 128–192 kilobits per second. Norwegian listeners noted that the sound of digital radio did not seem to be as good as the sound of FM stations (in addition, the sound of digital stations sometimes begins to gurgle). The problem will be solved by the new DAB+ format, which compresses sound using a more advanced HE-AAC method and transmits higher quality sound even with a lower bitrate.

A regular receiver does not pick up a digital radio signal, and a digital one is more expensive than an analogue one, for example, in Norway - €100–200. Norwegians fear that older people will not buy receivers and will find themselves without their usual source of news. Motorists will need new receivers: now in the country. But buying a DAB receiver will not save you from new expenses. If Norway decides to switch to DAB+, listeners will again have to upgrade their equipment: DAB receivers do not pick up the DAB+ signal.

Does this mean the end of FM radio?

Most likely, analogue radio will be phased out. In 2017 digital radio. The UK plans to switch from FM radio to digital once it reaches half of all listeners and coverage reaches 90% of the country. Perhaps this will happen by 2020. Denmark and Switzerland plan to switch to digital radio in the coming years. DAB testing will begin in Italy next year. Germany wanted to give up FM radio, but then changed its mind.

Will digital radio appear in Russia?

The State Radio Frequency Commission has been testing digital broadcasting since 2000. Russia even has its own digital radio format - RAVIS, Russian Real-Time Audiovisual Information System. In 2010, Russia planned to launch digital radio broadcasting in the DRM (Digital Radio Mondiale) format, but in 2015, the Russian Television and Radio Broadcasting Network returned to the idea of ​​launching DAB+. RTRS in three districts of Moscow - in Khoroshevo-Mnevniki, Kuntsevo and Tagansky district. In residential areas the reception was stable, on the Moscow Ring Road it was unstable, and outside the Moscow Ring Road - in the Krasnogorsk district - the signal was received only in low-rise buildings.

04/16/2018, Mon, 00:04, Moscow time, Text: Igor Korolev

The State Commission on Radio Frequencies is returning to the issue of building DAB+ digital radio standard networks in Russia, which was postponed for several years. RTRS has successfully tested the operation of this standard. It is planned to allocate a range of 174-230 MHz for it.

SCRF will consider the issue of digital radio standard DAB+

The State Commission on Radio Frequencies (SCRF), at its meeting scheduled for April 16, 2018, plans to consider the issue of introducing digital radio broadcasting of the DAB+ standard in Russia. This follows from the agenda of the commission meeting, which is available to CNews.

It is expected that SCRF will allocate frequencies in the range of 174-230 MHz to an indefinite number of people for the construction of DAB+ networks. The initiator of the consideration of the issue is the state enterprise “Russian Television and Radio Broadcasting Network” (RTRS), which is engaged in on-air television and radio broadcasting.

The commission will consider a report from the state enterprise Scientific Research Institute of Radio (FSUE NIIR) on the possibility of operating DAB+ networks in Russia and the conditions for their electromagnetic compatibility with existing networks. A study conducted by NIIR showed the possibility of DAB+ operating in parallel with other radio-electronic equipment using this range, including analog and digital television, military equipment, Roscosmos transmitters, etc.

The RTRS press service confirmed to CNews that at the SCRF meeting the organization will report on the results of the DAB+ testing carried out on its network. Tests confirmed the possibility of using this standard.

The Ministry of Telecom and Mass Communications fears that digitalization will destroy the radio broadcasting market

Talks about the digitalization of radio broadcasting have started in Russia since the late 1990s, simultaneously with talks about the digitalization of television broadcasting. Initially, for digital radio it was planned to use the ultra-short range oriented DAB standard, the predecessor of the DAB+ standard.

SCRF returns to the issue of building DAB+ digital radio networks in Russia,
postponed several years ago

But no work has been carried out in this area. In 2008, work began on digitalization of television in DVB-T standard. At the same time, another standard will be used for digital radio - DRM, intended for broadcasting on short waves. But in the field of DRM, no significant work has been carried out either.

In 2015, authorities began to think about the DAB+ standard. In Moscow, a study of the possibilities of its operation was carried out, based on the results of which the SCRF had to make a decision on the possibility of allocating frequencies for this standard. However, the decision was postponed for further testing.

However, in the corridors of power there is still no consensus on whether it is worth launching digital radio in Russia. As the Deputy Minister of Communications told CNews Alexey Volin, he opposes the digitalization of radio broadcasting: the transition to digital will lead to an increase in the number of broadcasters and will kill the radio broadcasting market, since there will not be enough advertising budgets for everyone.

What speed is needed so that the music does not seem “monotonous”

The DAB standard was approved in Europe in 1995-1997. It can operate in the range from 30 MHz to 3 GHz and provide input bit rates from 8 Kbps to 384 Kbps. DAB uses MPEG Audio Layer 2 encoding technology. Thanks to this, the standard provides broadcast quality similar to CDs, although they require a significant amount of time to play them. high speed- 1.4 Mbit/s.

DAB+ is an improved version of the DAB standard. This technology can operate in the ranges from 47 MHz to 3 GHz. Input bit rates range from 8 Kbps to 172 Kbps, supporting sampling rates of 16 kHz, 24 kHz, 32 kHz and 48 kHz. The standard uses a more modern audio compression technology than DAB - MPEG-4 He-AAC v2. This allows more radio stations to be broadcast on the same frequency.

So, according to the report of the Air Force Academy attached to the materials of the SCRF. N.E. Zhukovsky and Yu.A. Gagarin, DAB requires a speed of 192-256 Kbps for high-quality broadcasting, and 128 Kbps for normal broadcasting. DAB+ requires a speed of 64 Kbps for high-quality broadcasting, and 48 Kbps for normal broadcasting. Accordingly, if the DAB standard allows you to fit 12 radio channels into one multiplex, then DAB+ - 18.

At the same time, the authors of the report from NIIR consider it a fallacy that high-quality broadcasting in DAB+ can be provided at a speed of 64 Kbps, thereby increasing the total number of channels. The NIIR report states that in Switzerland DAB broadcast+ is carried out at speeds of 64-84 Kbps. This leads to sound distortion typical of digital compression, which is especially noticeable in music programs, which become quite monotonous.

As a result, the stated goal for digital radio – to provide broadcasting with quality comparable to CDs – cannot be achieved, NIIR states. Moreover, most paid and free music services on the Internet operate at speeds from 192 Kbps to 360 Kbps. Accordingly, for high-quality DAB+ broadcasting, a speed of 128 Kbps is required, while at speeds around 64 Kbps, digital radio becomes uncompetitive next to them.

What can DAB+ transmit besides sound?

A feature of the DAB/DAB+ standards is the ability to transmit a dynamic range control (DRC) signal, which can be used in the receiver to compress the dynamic range of the reproduced audio signal in noisy conditions. Also this technology will be useful for people with impaired hearing.

DAB+ transmits a multiplexed data stream in which several programs are transmitted simultaneously. Multiplex contains: data sound programs; auxiliary data, including program associated data (PAD channel); multiplex configuration information (MCI) and service channel (SI).

As a result, the digital radio user, in addition to the audio signal itself, receives additional receiver functions (dynamic range control), text display of selected information in the SI channel (information about the selected program), additional features to select other programs and one or more data services general(for example, a message channel about traffic– TMC).

The DAB+ standard can support conditional access technologies that allow audio to be transmitted only to a certain circle of subscribers (for example, those who have paid for a subscription). There is also the opportunity to organize additional channel data transmission using channels not used for audio transmission at speeds up to 16 Kbps. The receivers also have a radio interface for exchanging data with a PC.

Data transmission can also be provided in the PAD channel at speeds from 0.66 Kbit/s to 64 Kbit/s. This is done by reducing the bandwidth of the audio channel. The channel can carry dynamic indication of the program label and service identification, and decoding is supported base language hypertext markup (HTML) and JPEG images.

Along with the program, service markup (SI) is also transmitted: program name; time and date; cross reference to the same or similar program, broadcast in another group of programs or simultaneously on an analogue AM or FM broadcast service; extended service label for program-related services; program information; transmitter identity and traffic message channel (TMC, may use a speech synthesizer in the receiver).

It is also possible to automatically switch to alternative channels of the selected program (for example, in the FM range). To enable the receiver to access each or all individual radio programs with minimal delay, a Fast Information Channel (FIC) is used to carry information about the current and subsequent multiplex contents. This information is Multiplex Configuration Information (MCI).

Which European countries have decided to completely abandon analogue radio?

DAB+ technology is being actively introduced in Europe. Norway began phasing out analogue radio broadcasting in favor of digital broadcasting last year. Switzerland intends to carry out a similar transition in 2020. DAB+ is also being implemented in Austria, Germany, Italy, Denmark, Belgium and Latvia. Outside Europe, this standard is used in Thailand.

At the same time, the authors of the report from NIIR warn about the danger of a sharp transition from analogue to digital broadcasting: most vehicles are not yet equipped with DAB+ receivers, which means that the refusal of analogue broadcasting will have a bad impact on the road situation due to the inability to receive emergency and emergency signals services

Tri-standard radios and smartphone with digital radio support

To ensure a range of compatible radio receivers, the European Institute of Telecommunications Systems has developed the Euro DAB standard, according to which subscriber equipment must support three technologies at once: FM, DAB and DAB+.

Also, the British non-profit organization Radioplayer introduced an HMI interface that allows the receiver to automatically switch between FM/DAB/DAB+ depending on the quality of the broadcast. And in 2016, South Korean LG introduced the world's first smartphone with DAB+ support - LG Stylus 2.

Russian digital radio standard

An alternative to DAB+ is the Russian digital radio standard "". In 2015, SCRF will conduct tests of this standard. Developer "Ravis" Alexander Dvorkovich told CNews that tests began in Kazan at the end of 2017, and soon they will be carried out in Izhevsk.

“My opinion is that a domestic standard should be introduced in Russia,” says Dvorkovich. – Ravis technology has a number of technical advantages over DAB+: it provides best noise reduction, surround sound transmission and even video.” Microcomputers with additional USB modules or television set-top boxes can be used as receivers in Ravis.

News about the development of radio broadcasting in the DAB+ (Digital Audio Broadcasting) format in Europe causes a little 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 year-long 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 also 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 traditional ranges 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 and multimedia services: video, text (information about road conditions, etc.), static images, etc.

This abbreviation stands for “Russian Real-time AudioVisual Information System” (abroad it sounds a little differently: RAVIS, Real-time AudioVisual Information System). It is intended for broadcasting in the ranges 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 later organized the Sad-Kom 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 specified ranges. It is no secret that in large cities there is already a problem of frequency distribution for new broadcasters (the ranges are not unlimited) and this solution would resolve the situation.

And here we move on to one of our first questions: what, in addition to the promised high quality audio content, can this system “boast” of compared to regular 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 obtained directly in a moving car, on 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 “RAVIS Real-Time Audiovisual Information System”.

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 by the Non-profit partnership for the support of regional television "Association of Regional Television Companies" to the 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 approximate cost future models - about 100 - 120 dollars.

Development ways

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.

As the deputy stated general director VGTRK Sergei Arkhipov, the reduction in broadcasting in the above bands is due to a decrease in state funding for VGTRK in 2014.

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. About radio receivers 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 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. Blue marked "interested"

As for Russian radio broadcasting in the DAB+ standard, here too the situation is at 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 Television and Radio Broadcasting (NAT), during the International Exhibition of Professional Equipment NATEXPO, a demonstration of radio signal transmission in the DAB+ digital standard was held 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 of various models, which received the signal from a transmitter specially installed on the Ostankino TV tower.

The following 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 means 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.

We dreamed so much about replacing numbers O th analog technologies in the 80s and 90s, that we did not notice how in many areas we had reached the final stage of this process. This stage is called analog switchoff - that is, literally, “turning off the anal O ha." It occurs when the digital version of a particular technology, product, process takes over the dominant number of users - and a decision is made to disable the analog version.

The solution can be either market-based (as with audio records, which were no longer produced due to lack of demand), or “brought down from above” (as with television, which is gradually being replaced by digital). But anyway last years showed that immediately after this, unexpected strengths anal O hectares that you wouldn’t want to lose. That is, it’s kind of a shame 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, though, and not soon, but the shutdown process has begun. The first to decide on it was Norway, which by the end of the year intends to forcibly transfer all state radio channels to digital broadcasting, while simultaneously turning off FM. Following it, Switzerland, Great Britain, Denmark and some others are heading the same course. And it’s worth observing this process, if only so as not to step on the discovered rake later.

The analog radio receiver has been an almost eternal thing: even models released half a century ago can still be used today. Digital receivers definitely won’t last that long! Changing standards will likely force them to be updated as frequently as we update mobile phones today.

Norway begins a planned shutdown of government-owned FM stations starting this week. Within a year they will stop broadcasting in FM format and will be transferred to DAB. Everyone knows what FM is. 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 served as a synonym high-quality sound: frequency modulation in combination with ultra-short wavelength allows you to transmit a stereo signal and place dozens of stations in the range. FM has disadvantages, for example, a short range (compared to CB and HF; FM can be heard only slightly beyond the line of sight), but this did not prevent it from becoming the de facto standard for music broadcasting in cities.

And now 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 a digital rather than analog signal, at a speed of 128 kbit/s, in the range just above FM, using noise-resistant coding and the MP2 compressor, which was popular in the past. The receiver, accordingly, needs to be digital, that is, you will have to buy a new one, but this promises serious benefits. In general, the benefits of switching radio to a digital standard are circular: absolutely everyone benefits!

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

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

Third, DAB benefits listeners. Unlike analogue broadcasting, the quality of which continuously decreases as you move away from the station, the quality of digital broadcasting is invariably 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 someone tell me this fifteen years ago, when the fashion for replacing anal was rampant O ha figure, no one would doubt the veracity of these words. However, today about half of radio listeners in the countries mentioned above use DAB on a daily basis. And the reviews... so-so! Why? Several reasons are given.

Looking ahead: DAB is already outdated and should be replaced with a more modern standard. But worse than that, different countries are introducing different variants digital radio. In Russia, for example, the international DRM standard has been approved as a priority.

Firstly, it turned out that noise immunity digital radio broadcasts greatly exaggerated. Nobody even remembers that such a signal cannot be received even at a short distance from cities: the reception radius of digital stations is always less than for FM. But even in cities and on major roads, due to difficult terrain and distances, there are areas in which the DAB signal weakens below the permissible level. And then the digital shows its worst side: the sound either disappears completely or turns into a meaningless gurgle - whereas the FM station would be heard, albeit with interference, but clearly! It’s also worth adding that a digital receiver is much more complex and expensive, and is also capricious when moving at high speeds: already moving faster than 120 km/h, it reduces the quality of reception.

Secondly, it suddenly emerged that DAB is an outdated standard. It is customary to encode sound using MP2, which (at the bit rates used) does not provide sound quality close to CD or even FM! When experiments with DAB were just starting, this did not matter, but today, when it comes to completely disabling FM, the situation appears in a different light. There is a solution: the DAB+ standard uses a modern codec from the MPEG-4 family, but old DAB receivers are incompatible with it! And this has raised suspicions of foul play among DAB proponents: what if the replacement of FM with DAB is intended only to allow corporations to profit by selling new receivers, and then profit from the upgrades every year?

Finally, thirdly, many people doubt the stated readiness of DAB stations for emergency situations. State radio stations are used, among other things, to transmit signals to alert the population about emergencies. But if FM could be received by everyone, then DAB in Norway - God forbid that every second resident (the rest simply do not have digital receivers). Digital communications also have the famous property of being the first to “fall” during natural disasters and catastrophes. Will this happen again with DAB?

As a result, the question of the wisdom of turning off FM no longer seems idle. Will digital radio ever replace analog radio? Or will it remain just an optional addition to an ancient, but not obsolete technology? What do you think?

Stages of DAB development

European firms founded the Eureka-147 consortium in 1987 with the goal of developing a fundamentally new system DAB digital radio broadcasting. The participants in this project are about 50 companies and organizations from the UK, Germany, France, Holland, Italy, Sweden, Switzerland, Norway, Finland, Japan, Canada, the USA and several other countries. In 1995, IRPA im. A.S.Popova.
In 1992, based on a worldwide agreement, DAB was allocated L- and S-bands. The first receivers, mainly for measurement purposes, were created in 1988. Since 1990, a number of members of the Eureka-147 project took part in the JESSI project, within which the first integrated circuit for commercial DAB receivers. The first consumer DAB receiver was presented at an exhibition in 1995 in Berlin. The miniaturization of receivers continues; currently, their serial production is carried out by Grundig, Philips, etc. Several tens of thousands of receivers are already in use in European countries.

Great Britain
In 1994, the UK government decided to allocate the 217.5-230 MHz frequency range for terrestrial DAB. This band can accommodate seven multi-program DAB signals (called “DAB blocks” or “ensems”), each occupying approximately 1.55 MHz of bandwidth. This provides guard frequency intervals between DAB signals of approximately 200 kHz wide. To facilitate the identification of ensembles, each of them is assigned a short identifier (11B, 11C, 11D, 12A, 12B, 12C, 12D). Ensemble 12B since September 1995 uses the BBC to broadcast five national programs received throughout the UK. Ensembles 11C, 11D, 12A, 12D are reserved for Independent National Radio (INR) Services.
Already at the first stage, an area covering the territory of London and its suburbs, which is home to more than 10 million people, was served. By now, more than half of the country's population can take part in the program.

Germany
In 1995, at a conference in Wiesbaden, it was decided on the possibility of using frequencies in VHF bands II (87 - 108 MHz), III (174 - 240 MHz), and in the L-band (1452 - 1467.5 MHz) for terrestrial DAB. In the same year, experimental DAB broadcasting of seven audio programs and service information from 13 radio stations on the frequencies of TV channel 12 began in Bavaria. Additional local programs are broadcast in L-band. In North Rhine-Westphalia by 1996, five transmitters operating at frequencies of TV channel 12 were installed; additional local stations began broadcasting in Cologne and Düsseldorf. At the beginning of 1996, 2,000 receivers were distributed among listeners; by the end of the same year, the population already had 15,000 thousand DAB receivers with varying levels of service. Since 1997, regular DAB broadcasts began in Bavaria.
Today, broadcasting in this standard covers more than 60% of the country's territory. It is expected that by 2004 the DAB signal will be available throughout Germany. The complete transition from analogue to digital broadcasting should be completed between 2010 and 2015. For broadcasting, a network of transmitters will be used operating in TV channel 12 (223-230 MHz, one DAB block for each land) and in the L-band (1452-1467.5 MHz), where 100 DAB blocks are given to regional programs. With this distribution, a minimum of twelve high-quality stereo audio programs and a number of supplementary information channels can be received anywhere in Germany using a DAB receiver with a simple whip antenna.

Russia
Work on the creation of a digital radio broadcasting system began in Russia at the beginning of 1980 at the VNIIRPA named after. A.S. Popov, which culminated in the creation of a domestic DVR system, prototypes of transmitting and receiving equipment and the organization of experimental broadcasting in Novgorod in 1993. However, since in 1995 the Eureka-147/DAB system, which differs significantly from the domestic one, was standardized as a pan-European system, then, starting from 1993, all work was focused on the implementation of this system in Russia. Unfortunately, what follows is mainly not facts, but intentions.
For experimental broadcasting in St. Petersburg, the Ministry of Communications decided to allocate a frequency band in the range 92 - 100 MHz. Experimental work was successfully carried out, however, these efforts are not enough to implement the specified CRV system throughout the Russian Federation. There is still no single federal program introduction of a digital standard on television and radio-electronic media.
To solve the broadcasting problem, it is necessary to solve many organizational problems, first of all, the allocation of a separate frequency range. European experience has shown that using the 88-108 MHz range in conjunction with existing FM stations is inappropriate. At the end of 1999, the board of the Ministry of Communications of the Russian Federation outlined a three-stage strategy for the transition to digital radio broadcasting, designed for 10-15 years:

2001-2002 Experimental broadcasting in Moscow and St. Petersburg of 6 state stations: “Radio Rossii”, “Mayak”, “Mayak-FM”, “Yunost”, “Orpheus” and one local one. It is possible to transmit paging or multimedia information.

2002-2003 Expansion of experimental broadcasting to the Moscow and Leningrad regions, the emergence of 6 commercial stations.

2003-2010 Full coverage of the territory of the Russian Federation, in the future - a reduction in the number of analogue VHF stations.

The range of 176-230 MHz was recommended for development. However, a strategy is not a program and real steps nothing has been done to implement this concept yet. Russian bureaucracy is stronger than progress. Specific frequencies in the recommended range can be allocated only after a lengthy analysis of the electromagnetic situation, which must be carried out by the Radio Research Institute. And after the allocation of frequencies by the Committee of the Ministry of Communications, they still have to win a competition for its use in the MPTR (Ministry of Press and Television and Radio Broadcasting). After this, the only thing left is to find funds to implement the project. You can’t count on government funding, much less public funds. Recently, some Western companies - manufacturers of DAB equipment - became interested in the state of the Russian project. Wanting to go out Russian market, they are ready to finance the deployment of an experimental broadcast zone. This is probably the most realistic scenario for a successful development of events.
On May 14, 2002, experimental transmissions of stereophonic sound broadcasting programs “Radio Russia”, “Mayak” and “Yunost” began in digital format via the communications and broadcasting satellite “Express-6A” (location point 80 degrees east) to the territory of Russia from Kaliningrad to Vladivostok. However, this is not yet a regular broadcast.

DRM SYSTEM

The DRM standard has been developed for medium and short wave bands. The developers decided to turn to these bands because they provide unprecedented opportunities for long-distance broadcasting at significantly lower costs for its organization, and the technical quality of broadcasting no longer meets modern requirements.
The DRM (Digital Radio Mondiale) organization was founded in March 1998. It is a non-profit international consortium consisting of more than 60 participants from Europe, Asia and America, including Russian channel"Voice of Russia". The new standard, called “system A,” is based on a modified prototype of the Skywave-2000 system, developed by the French company Thomcast. In the fall of 2000, the International Telecommunication Union recommended its members to use it, after which the name “DRM system” stuck.
The format is characterized by flexible transmission parameters, allowing it to be used in all bands below 30 MHz. At the same time it can be used for the VHF band. The first DRM systems will broadcast in the standard radio channel bandwidth of 9/10 kHz. Subsequently, wider streams can be generated, increasing the quality of signal transmission. To implement the new system, existing AM transmitters can be upgraded, which will remove a number of transition problems.

The main advantages are as follows:


Improved reception and sound quality

Possibility of use in all ranges

Combined data and audio transmission possible

There is a choice of modes to optimize throughput/quality and reception reliability/stability

Very high spectral efficiency: 3 to 4 bit/Hz/s;

The system is open to future improvements, new compression methods and encoding processes. For RF broadcast channels below 30 MHz, a bandwidth of 9 or 10 kHz is currently used.

DRM system can be used:


within the nominal bandwidth, in accordance with this plan;

within channels with a bandwidth of multiples of 4.5 kHz (half 9 kHz) or 5 kHz (half 10 kHz), in order to be able to co-broadcast with an analogue AM signal or to provide higher transmission capacity if this is allowed in the future.

Brief description of the DRM standard

Unlike the DAB standard, which uses MPEG II, DRM uses a more modern version of MPEG-4 compression. It includes an adaptive AAC (Advanced Audio Coding) signal compression engine in mono and stereo options, as well as CELP (Code-exited Linear Prediction) for high-quality coding of speech and noise-like signals. In MPEG-4, long-term prediction is carried out not in the time plane, but in the spectral plane. The encoder makes a prediction and then encodes either the difference between the actual and predicted signal, or the input signal itself if its value can be encoded more compactly than the difference. In addition, the encoder supports several new mechanisms related to the stream's ability to adapt to changes in channel parameters. Any of the options can be supplemented with the SBR (Spectral Band Replicatoin) technique, designed to improve the quality of high-frequency transmission. When transmitting at frequencies below 30 MHz, all formats except stereo use the 9/10 MHz band. The use of SBR technology requires a wider bandwidth.
In addition to audio signals, data can be transmitted in a digital stream. The multiplexed audio and data stream form the Main Service Channel (MSC). Up to 4 streams are transmitted to the MSC, each of which carries either audio or data. The MSC channel information is divided into logical frames of 400 ms each. In addition to the MSC, two additional channels are formed. The main and service channels are multiplexed in a certain way, resulting in the formation of transport superframes with a duration of 1200 ms.
The first additional channel, Fast Access Channel - FAC (high-speed access channel), carries data on the parameters of the radio frequency signal and information that allows you to highlight individual services. Signal parameters include stream identifier, occupied bandwidth, modulation type, coding type, interleaving depth index, number of transmitted services. These parameters are transmitted in every FAC frame. Parameters that characterize services include an indication of the type of service (audio/data), a conditional access flag, a language indicator, and some others. They are transmitted sequentially - in one frame, parameters related to one service.
The second additional channel, Service Description Channel - SDC (Service Description Channel), contains information related to conditional access, program guides, copyright information, supporting information for some applications, as well as links to alternative frequencies on which the same channel is transmitted. SDC information is placed at the beginning of each superframe and begins with references to alternative frequencies. This allows you to automatically select the channel currently being received the best way.
DRM, like DAB, uses the COFDM modulation system. This system is very effective for transmitting signals over a radio channel with multipath propagation of radio waves and selective signal fading, characteristic of short waves. A guard interval is used to compensate for multipath interference. It should not exceed 20% of the total symbol duration so as not to reduce the channel capacity. The number of carriers placed in the channel's frequency band is limited by the Doppler frequency shift of the signal that occurs in mobile reception mode. Taking these factors into account, approximately 200 carriers are used in the 9/10 kHz band. Their exact number, as well as the duration of the symbol and the guard interval, depends on the nature of the propagation of radio waves (surface or spatial), the expected transmission range and the required reliability.
The channels included in the MSC are divided into 2 parts, differing in the importance of information for correct decoding. They are subject to separate noise-resistant coding, characterized by varying degrees of noise immunity. As noise-resistant coding, data interleaving and convolutional coding with code rates from 0.5 to 0.8 are used. Data interleaving in COFDM systems is implemented in both time and frequency, which allows signal restoration at a high level of selective fading in the radio channel. In addition, to combat this phenomenon, pilot signals are introduced into the stream, allowing the receiver to estimate the degree of attenuation of the signals at each carrier frequency. The level of protection imposed also depends on the range and expected distance of the signal. In particular, when transmitting on short waves, the interleaving depth is 2.4 s, and on long and medium waves - 0.8 s. In addition, on short waves, convolutional coding is used with more low speeds code and more pilot signals are introduced.

PROSPECTS FOR DIGITAL BROADCASTING

It must be recognized that digital broadcasting is superior in quality and capabilities to analogue. However, qualitative superiority does not always translate into quantitative superiority, as happened with the DAB standard. Therefore, digital broadcasting will not completely replace analogue broadcasting very soon, and it is too early to talk about the disappearance of traditional radio. It was expected that in almost all developed countries of Europe since 1997-98. Regular DAB broadcasting will begin, and by the year 2000, coverage of 80% of the European population will be completed. However, the actual rate of coverage is noticeably lower than forecasts. Manufacturers are in no hurry to increase the production of appropriate receivers because they are not confident in the sales market. And the market is not ready to accept new receivers, since the majority of listeners are satisfied with the quality of analogue broadcasting on VHF and do not yet see the possibilities of the new format. There is also real competition from record companies interested in listening to recordings rather than radios in cars - sales revenues significantly exceed the royalties of radio stations.
The original mistake was that DAB was seen only as a technical standard. However, the history of technology clearly demonstrates that technical advantages alone are not the decisive argument for the mass consumer when choosing a product; there must also be some other advantages. Guessing what will be in demand by the market is an impossible task. Suffice it to recall such recording formats as DAT, DCC or minidisc, which have not supplanted the compact cassette and are retreating under the onslaught of solid-state memory.
When developing DAB, the possibility of transmitting additional information was included initially, but the broadcasting concept was initially preserved: the same principle of constructing programs, the same annoying advertising. Today's broadcast programs are primarily aimed at the faceless average listener and appeal to a national audience. With this approach, it is impossible to take into account the regional characteristics of the audience, local interests and traditions, etc. The DAB standard is designed for local and regional broadcasting and fully meets the interests of commercial radio, but in general the change in strategy is quite slow. To interest the consumer, and thereby stimulate the manufacturer, the BBC was the first to create a new program for digital format, other broadcasters followed suit.
DAB radio is planned to be used not only for broadcasting traditional radio programs (free and encrypted), but also for transmitting business information. It will be displayed on the DAB receiver display or on the computer monitor in the form of teletext. This possibility exists thanks to the use of the MOT (Multimedia Object Transfer) protocol, designed to bring heterogeneous data to a standard teletext format. In addition, it is planned to use DAB services to transmit encrypted information intended for a narrow circle of subscribers. This service can be used by banks, insurance offices and other organizations to distribute information between branches.
Another service that is expected to be developed within the framework of national DAB projects is the provision of information on road conditions. This is especially true given that DAB radio is heavily geared towards mobile reception. In addition to providing a wide range of related information, digital broadcasting offers the possibility of providing on-demand programs and other interactive services. In mobile receivers, it is intended to use GSM networks.

The future position of DAB in the market may be negatively affected by the widespread adoption of DVB satellite television broadcast receivers, which are clearly favored by both industry and radio stations. The commissioning of digital multiplex radio dRadio ensured the broadcast of up to 40 uncoded radio programs in MPEG-2 format via the HotBird-5 satellite in one single DVB channel. The salvation of DAB so far is that only stationary receivers have been developed for DVB, designed for operation in one of three modes: DVB-S (receiving a signal from a satellite), DVB-C (via cable) and DVB-T (terrestrial). However, new direct systems satellite broadcasting allow you to receive programs in a moving car.
At the end of 2001, America began regular work two national networks satellite direct digital radio broadcasting - Sirius Satellite Radio and XM Satellite Radio. Dozens of new high-quality radio programs immediately appeared on the air. Experts note not only a fundamentally different business model for satellite radio broadcasting, which can exist without traditional radio advertising, using the money of subscribers, but also the expected revolutionary changes in programming and in the choice of content for listening programs, which will become available to radio listeners themselves. This entire range of pleasures costs the listener $9.95 a month. The companies are confident that, as in the case of cable television, the audience will want to pay for something that directly satisfies its interests and does not contain advertising that many people hate. Sirius Satellite Radio and XM Satellite Radio are full of optimism, and the cost of the receivers is already comparable to the cost of existing car radio equipment. Considering that about 24 million car receivers are sold annually in the United States, it is predicted that by 2007, 15 percent of all cars will be equipped with satellite broadcast reception equipment.
Three satellites Sirius Satellite Radio cover digital signal the entire US territory. Reception is carried out using an antenna measuring 20-30 cm. In addition to satellites, the company has deployed a network of 100 ground-based transmitter-repeaters. 100 channels are broadcast from satellites in MPEG-2 format.
XM Satellite Radio Holdings Inc. offers radio listeners 71 music channels, their repertoire covers a lot of musical styles from classical music before rock. In addition, radio listeners are offered news channels, materials for which are provided by CNBC, CNN Headline News, USA Today and C-SPAN, as well as a number of other agencies. Sports and entertainment programs, talk shows and programs for children are broadcast via satellites. In the space segment of the satellite digital radio broadcasting system, there are two communication satellites codenamed Rock and Roll. The signal is received from satellites directly to radio receivers, and in urban areas with multi-story buildings, ground-based repeaters will be additionally used to broadcast the signal.

The main advantage of direct satellite broadcasting over existing VHF radio stations is globality. However, the costs of creating such a system are quite high. In countries and regions with low population densities or located at a significant distance from the equator, satellite radio may be ineffective and unpopular for purely economic reasons. And in some cases, terrestrial digital radio broadcasting has more prospects in the foreseeable future, in contrast to the United States, at least due to the orders of magnitude lower costs of their implementation. This is where DRM comes into the picture.
The development of digital broadcasting in long-range bands is especially important for Russia, given its vast territory and average population density of 9 people per square kilometer. In small towns, where more than half the country's population lives, commercial VHF-FM broadcasting is often unprofitable. Therefore, excellent prospects are open for the almost forgotten ranges below 30 MHz in Russia.
However, there are other problems. When introducing digital radio broadcasting in the AM bands, it is necessary to ensure that the reception capabilities of more than 2 billion existing analogue radio receivers are maintained. This can be achieved by simultaneously transmitting a half-rate digital broadcast signal and a compatible single-sideband analogue broadcast signal. In this case, owners of conventional radio receivers will receive an analog program, and a digital one will be heard as weak high-frequency noise. The radio frequency spectrum of the emitted compatible signal does not exceed the 9 kHz allocated today by the ITU for one radio channel. In a purely digital transmission mode, the spectrum of the transmitted signal can occupy the same standard 9 kHz or, in the case of an extended mode, 12 kHz, while achieving improved sound quality and the transmission of additional multimedia information.
The digital technology behind future DAB receivers will also make it possible to receive DRM signals. For radio stations, the transition to digital broadcasting in the short, medium and long wave bands means a significant (by about three-quarters) reduction in broadcast costs while maintaining the same coverage radius. At the same time, transmitting stations can continue to use the existing infrastructure.