The Russian authorities have returned to the idea of digital radio. Digital broadcasting (DAB, DRM)
We dreamed so much about replacing numbers O th analog technologies in the 80s and 90s, we did not even notice that 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 in any case, recent years have shown that immediately after this, unexpected strengths of anal are discovered 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 for high-quality sound: frequency modulation, combined with an ultra-short wavelength, makes it possible 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) 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, different versions of digital radio are being introduced in different countries. In Russia, for example, the international DRM standard has been approved as a priority. Firstly, it turned out that the noise immunity of digital radio transmission is 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 the same 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?
Well, what kind of digital radio did they come up with? We already have numbers in the receiver instead of a scale and the names of the stations are displayed! Do we need it? Will it reach Russia by air or via their Internet? There is no answer here in a few words. Let's try in three.
Here's what interested parties say about this - Digital Radio Development Bureau (DRDB):
“This is not satellite radio, and not Internet radio. No, that's not it. In fact, this is a new way of radio broadcasting through a network of terrestrial transmitters.
It gives you more freedom of choice, better sound quality and a lot of additional information. In general, almost like a regular radio, only better.”
Such are the optimistic messages. How much better? And what additional information is offered to us?
To begin with, we note that we are talking about DAB radio (Digital Audio Broadcasting), since no one forbids calling both satellite and Internet radio digital - there is no monopoly on the adjective.
For lovers of antiquity: Evoke-2 with FM range (photo from pure-digital.com).
Therefore, if we literally translate the phrase DAB digital radio, which is scattered in abundance on the pages of DRDB, we get - “digital radio of the digital audio broadcasting type.” It’s a complete tautology and nonsense, but that’s how it is in a world where an enemy lawyer is waiting for you around every corner.
The DAB standard has been developed since the late 1980s by a consortium of 12 companies called EUREKA-147. In 1994, it was proclaimed as a global one, minus the dissenting opinion of the USA and Japan.
The Americans, however, rely on satellite and HD radio (High Definition), and the Japanese entangle themselves in cable radio networks (just like we do with the ever-memorable three-program loudspeakers, only without the Japanese numbers).
Of all the other countries, DAB radio is doing best in Sweden, Germany and the UK. Of course, the British are conservative people and prefer the centuries-old (one with a small tail) terrestrial broadcast on the radio.
In fact, each country is free to choose its own frequency range, within the limits imposed by the standard. The British liked 217.5 - 230 MHz. Well, let them tell themselves, the neighbors still can’t hear it, because there is complete down-to-earthness.
A tempting offer from the Ministry of Sound (photo from ministryofsound.com).
Let's say, a UHF device (Band III) for the English market will still work in Germany, although some stations broadcast there in the L band, but in Canada, where there is already one continuous L DAB broadcast, it will have to rest. Unfortunately, dual-band receivers are not yet produced.
How does DAB broadcasting work? First of all, radio stations are not broadcast individually, but as part of a block called a multiplex.
The same package may contain information of a different nature - text and graphic, which is especially convenient for mobile users: all kinds of motorists, tourists, and traveling salesmen.
A strange thing - a digital radio for a digital computer (photo from modulartech.com).
More precisely, at the end of the twentieth century they counted on such unsurpassed amenities. And now all self-respecting citizens already have multimedia mobile phone organizers with widespread access to the wireless Internet, so such radio standard capabilities will most likely remain a pleasant and unuseful addition.
Let's go back to multiplexes. All component signals of the packet, using the COFDM (Coded Orthogonal Frequency Division Multiplexing) system, which performs time-frequency sampling of the analog stream and its digitization, are mixed in a special way and modulate a certain number of carrier radio waves, the number of which depends on the information richness of the broadcast (according to the carrier standard, there can be from 192 to 1536).
Then all this wealth, through transceiver devices, enters the user receiver, is decoded by the audio processor and, finally, begins to delight the ear of the listener, who does not care about all sorts of cofdm and multiplex.
Unobtrusive high-tech (photo from pure-digital.com).
What does the consumer get from the new technology? - here it is, the main question.
To begin with, the notorious CD-quality sound is achieved - digital after all.
Well, this is not the main, albeit useful, property: the acoustics of a portable or kitchen receiver are still not so great, but where else do we listen to the radio? Although music lovers, car enthusiasts and wearers of good headphones can feel the difference compared to regular FM transmission.
What is more important is the use of hidden radio air reserves. Both for listeners and radio journalists, along with advertisers. In developed countries, there is nowhere for the apple to fall in the FM range: everything has long been divided and redistributed.
And with a DAB receiver, most Brits can listen to fifty new stations - twice as many as on analogue radio. And this is just the beginning.
Now about the interference that inevitably accompanies radio transmissions: there is none. Either you hear everything perfectly, or you hear nothing at all. In the city, as we know, radio interference does not make itself too noticeable due to the proximity of the transmitters, but in uninhabited rough terrain all these snake hisses, crackles and interruptions in sound unfold in full force.
With headphones you will understand what DAB is (photo from pure-digital.com).
And, by the way, DAB broadcasting is ensured by lower transmitter power. Electricity, you know, is saved, and the coverage is greater. Surprisingly, only 65% of UK residents can receive the BBC in one form or another, while commercial DAB broadcasts can already be received by 85%.
It’s also nice that the receiver quickly scans the entire range, and then you just have to choose among the names of available stations, completely forgetting about the inconvenient frequency numbers.
Well, we have already spoken about the topic of various pictures and signatures, for which 20% of the channel’s bandwidth is reserved. But you shouldn’t neglect these 192 Kb/sec either: even if it’s not the Internet, you can find something useful for free and among advertising.
This is how things stand today. What does the average English consumer say?
Until recently, he was silent: prices for receivers started at 400 pounds (about $630). The breakthrough was made by a small company, Imagination Technologies, which until then had nothing to do with the radio market, although there are more than 20 manufacturers of DAB equipment.
She decided to bet on this sluggish technological area, in a year and a half she developed a perfect microprocessor and programs, after which she launched the Evoke-1 receiver on the market (translated as “to call”, but it can be sounded like “eva like”) for less than the magic 100 pounds ( about $157).
7 Radio was most valued in the old days (photo from bbc.co.uk)
And then everyone began to stir. Since last Christmas, 135 thousand receivers have already been sold (over the entire period until 2002, the British purchased only 50 thousand), the company cannot cope with orders, experts predict millions of copies, and that by 2010 the usual FM radio may completely die out in favor of DUB.
And in the reception area of Imagination Technologies, along with others, Sharp, Intel and Hitachi were spotted - give them a license. And a dozen different models are already ready. But let's return to our homeland.
As you can see, we were never able to give a clear answer to the last two questions identified in the preamble of the article. They preferred a figure of silence and transferred these questions to the category of rhetorical.
Do we need it? We’re not prophets, we don’t know for sure, which means we’re not sure, and besides, we haven’t tried it. Will we wait in Russia?
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 upgradable.
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 a bitrate set at 128 kbit/s, popular programs are set at 112 kbit/s, and for example, an information stream may use 64 kbit/s. When reading these values, keep in mind that the stated figures may not always correspond to audio throughput. For example, if a station advertises the bit rate at the 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 already in the mid-90s, while consumer models appeared on the market in the summer of 1998. Home radios in an 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+ .
Adapter for DAB connection in car 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, Germany's Radio Horeb transmits at 48 kbit/s, and some music programs (including the 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 represents seven times the data rate of the best quality broadcast available on the sender's website, which is 360 kbps quality. Additionally, unlike FM station programs, which can be received with noise and signal interference, loss of the digital radio signal will cause reception to be completely interrupted. Motion-related glitches are also more common than in FM.
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 the 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 much higher speed of 1.4 Mbit/s to play them.
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+ broadcasts are 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. This technology will also be useful for people with impaired hearing.
DAB+ transmits a multiplexed data stream in which several programs are transmitted simultaneously. The multiplex contains: audio program data; 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 options for selecting other programs and one or more general data services ( e.g. Traffic Message Channel - 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). It is also possible to organize an additional data transmission channel using channels not used for audio transmission, at speeds of 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 program label and service identification, and supports decoding of basic Hypertext Markup Language (HTML) and JPEG images.
Along with the program, service markup (SI) is also transmitted: program name; time and date; a cross-reference to the same or a similar program carried in another program group or simultaneously on an analog 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 better 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.
