DVB-T2 is the second generation European standard terrestrial digital television broadcasting DVB-T.
TV broadcasting of the DVB-T2 standard is carried out using MPEG-4 coding, the stream rate is up to 50 Mbps. digital format ensures picture stability even in high noise and interference environments. In this it is fundamentally different from the analog format, which is characterized by systemic distortions.
Note. The DVB-T2 standard is the latest in the family of DVB terrestrial digital broadcasting standards, because it is impossible to physically realize a higher data rate in a spectrum unit.
DVB-T2 has fundamental differences from DVB-T both in terms of the system level architecture and the physical layer. This is the reason for the incompatibility of DVB-T receivers with DVB-T2.
The DVB-T2 standard has undeniable advantages before its predecessor: it is designed to increase the bandwidth of the radio channel by at least 30%, while the infrastructure existing networks and frequency resources do not need to be changed. This will expand the number of transmitted TV programs on one RF assignment, as well as improve the quality of radio frequency networks.
Despite the fact that the DVB-T2 standard is a follower of DVB-T, it has improved and expanded functionality. While maintaining such basic signal processing ideas as scrambling, as well as data interleaving and coding, each of the stages has been improved and supplemented. The changes did not affect only OFDM modulation (orthogonal frequency multiplexing).
For data encapsulation in the DVB-T2 system, it is possible to use the transport stream not only MPEG, but also general purpose(GSE). This provides a reduction in the amount of transmitted overhead and makes the adaptation of the flow to the network more flexible. Compared to its predecessor (DVB-T), the DVB-T2 standard is not tied to any data structure at the transport layer.
The differences also lie in the use of the band. If in the DVB-T standard the entire band is used to transmit one stream, then in DVB-T2 the so-called. PLP concept. This abbreviation stands for Physical Layer Pipes, or channels physical layer, and means the transmission of several logical channels in one physical. 2 modes are possible:
mode A - transmission of one PLP;
mode B - multi-PLP (or multiPLP) transmission. At this mode there is a simultaneous transmission of several transport streams, while each of these streams is placed in its own PLP. This allows the coexistence of services that are transmitted with different degrees of noise immunity in one radio frequency channel. It is possible to select the modulation mode and error-correcting coding mode individually for each PLP. In other words, the operator for each program in the packet can choose a higher bit rate or better noise immunity. The receiver decodes only the selected PLP, and itself is turned off for the duration of the transmission of PLPs that are not of interest to the user. This ensures energy savings.
The DVB-T2 standard has a more complex interleaving system. Bit, frequency interleaving is used, as well as additionally temporal. It is carried out both within one modulation symbol and within a superframe, which makes it possible to increase the stability of the signal. impulse noise, as well as changing the characteristics of the transmitting path.
For the DVB-T2 standard, there are 8 ways to place pilots. That is, if for DVB-T the number of pilots from total number carriers was 8%, then for the DVB-T2 system, variation is possible given value: 1, 2, 4 and 8%. The layout is affected by the size of the guard interval.
Another innovation of the DVB-T2 standard is the rotation signal constellation, which improves the noise immunity of the system.
Thus, key features DVB-T2 are:
compared to DVB-T: no less than 30% increase in capacity and improvement in SFN performance;
transmission robustness defined by the service;
transmission of programs to both mobile and fixed receivers;
use of the existing DVB-T infrastructure;
lower operating costs on the transmission side due to a reduction in the peak power/average power ratio.
When it comes to buying a new TV, most people only focus on quality. transmitted image, as well as those specifications on which it depends. The price of the device is also important. But the presence or absence of a digital tuner, as well as its type and quantity, is of little interest to anyone. Not many people pay attention to it. As a result, when there is a desire to connect and watch DTV for free, problems arise and you have to spend money to buy a DVB-T2 tuner separately.
Today we will look at what a digital tuner is, what it can be and how it works. This will allow you to approach the choice of a new TV more carefully and decide for yourself whether you need such a device built into the TV or not. Moreover, as already mentioned, a digital tuner can always be purchased separately.
What is DTV T2
Before considering the features and types of tuners that exist on TVs today, you need to understand what, in principle, is this device and what it is for. A digital tuner is a receiver or, as it is also called, a decoder that allows the TV to directly receive signals various types broadcasts and decrypt them.
Many new TV models already have a built-in digital receiver T2. In addition, there are divisions in which there are two tuners at once - T2 and S2. You can find out what type of device is built into your TV by looking at its technical specifications. If you have a built-in decoder that accepts a signal of a different format, then the necessary tuner can always be purchased separately.
External tuners are very popular today, since not many Russian citizens have the opportunity to spend a large amount of money on buying a new TV, and such a set-top box allows you to expand the capabilities of an existing device. The most popular are set-top boxes in the T2 format, which allow you to connect and watch, as well as the DVB-S2 set-top box. They buy it if they decide to install a satellite TV antenna, but there is no decoder of this type on the TV.
Broadcast standards
As already mentioned, the tuner built into the TV can receive one or more signals. different format broadcasting. Consider the most common options.
- DVB-T. Such a receiver can receive a digital television signal that transmits a picture more high level quality and clarity. To connect it, you need a regular TV antenna.
- DVB-T2. This is the second generation of DVB-T decoders, which differs from its predecessor in increased throughput channel, more high performance signal and its architecture. On the territory of Russia, this DTV signal format is mainly used. It is impossible to receive it through the DVB-T decoder, as these formats are incompatible.
- DVB-C. A very popular format capable of decoding a digital signal cable television. To start using it, you need to insert a provider card into the appropriate slot.
- DVB-S. With it, you can directly connect a satellite dish to your TV.
- DVB-S2. Like T2, S2 is the second generation DVB-S receivers. S and S2 are also incompatible, so to receive a signal of this type you need an appropriate decoder. Is different given format increased channel capacity and the use of new types of modulation.
When buying a TV, you should pay attention Special attention for marking. So, you can see the inscription DVB-T2/S2. This means that the TV will be able to receive both terrestrial and satellite digital channels.
Features of DVB-S2 and DVB-T2
Built-in digital tuner satellite television has certain features. In order to watch free available TV channels, it will not be enough for you to simply connect a satellite dish to your TV directly. You will also need to purchase an additional CAM module.
The fact is that without it you will not be able to view encrypted channels, but only those that are completely open. This is due to the fact that companies involved in the production of such TVs do not really think about this. In addition, it will be impossible to change the firmware or enter the code. External satellite tuners, sold with us, have firmware, in which all the necessary codes are already entered.
The new DVB-T2 digital television standard in simple answers to the questions of concern to residents of the region.
What is DVB-T2?
This is the second generation of the European digital terrestrial television standard. It differs significantly from the first DVB-T generations physical characteristics. It is for this reason that set-top boxes and TVs with a DVB-T receiver are not compatible with DVB-T2. The second generation standard is used in a number of countries of the European Union, Ukraine, Belarus, Kyrgyzstan, Tajikistan and Armenia.
In Russia, DVB-T2 is chosen as the standard for digital on-air television within the framework of the Federal target program "Development of television and radio broadcasting in Russian Federation for 2009-2015". Federal State Unitary Enterprise Russian Television and broadcasting network”, the executor of the program, formed two free packages(multiplex) of two dozen channels.
What is the difference new standard digital terrestrial television from the old?
Through the possibilities modern equipment and more complex mathematical signal processing in the new standard, the capacity of broadcast networks increases significantly, allowing you to transmit more information in digital package. The standard provides for the prospects for the organization of "local" broadcasting. The DVB-T2 stream is better protected from interference. Subject to the release of the frequency resource, it becomes possible to receive more channels in high and ultra-high definition modes and even watch 3d television.
In addition, already now, during the broadcast of the first and second multiplexes, viewers can access new service: "TV Guide". In general, DVB-T2 TV is more adapted to the implementation of SMART functions.
Why do we need these changes at all, if everything suited me before?
First, to be sure of the future. Digital television has already replaced analog almost all over the world. The DVB-T2 standard has been chosen as the main one for use in Russia at the highest federal level, which means that in the future all television broadcasting will be based on it.
Besides, modern life directly depends on information flows, and you should not ignore the data transmission capabilities provided by the DVB-T2 standard. If earlier the TV was only a means for watching several TV channels, today it already combines a lot of functions, from recording missed programs to working with the Internet.
In the end, despite the fact that analogue broadcasting of channels is still available in in full, the final transition to digital television- just a matter of time. Contain outdated technologies analogue TV broadcasting is too expensive, and new technologies provide a lot of opportunities to improve the quality of life of Russians.
Who was affected by the transition to the new DVB-T2 broadcasting standard?
The changes affected only those residents of the region who were already subscribers of digital television and used the equipment of the previous DVB-T standard. TV boxes, televisions with built-in decoders and computer TV tuners DVB-T are incompatible with the new standard, and the broadcasting of multiplexes in the old standard on the territory of the Kaliningrad region has been discontinued since mid-January.
However, according to statistics, most residents of the region today use cable or satellite television, as well as IP-TV. These subscribers were not affected by the transition to the new standard. Only subscribers cable networks for several days, rare interruptions in the broadcast of individual programs could be observed.
What equipment is required to watch channels in the new standard?
Firstly, you will need an antenna - either a common one on the roof, or your own indoor one.
It is very likely that your TV already supports digital television standards adopted in Russia (DVB-T2 standard, MPEG-4 compression, Multiple PLP mode). Most of the world's leading manufacturers supply such TVs to our country. If you are only going to buy new tv, make sure it supports these standards.
If for some reason your TV is not compatible with digital TV standards, then you need to purchase a set-top box to receive reception. digital signal. It may also be referred to as digital broadcast receiver or SetTopBox(STB). The standard of the set-top box is usually written on the front of the set-top box, make sure the set-top box supports the DVB-T2 standard.
If you want to receive a digital TV signal and cable TV channels at the same time, then you will need a so-called TV signal adder.
It is important to know what your satellite antenna does not allow you to use digital TV broadcasting, as it works in a completely different standard. In addition, it should be noted that one prefix does not allow you to watch various channels digital television on different TVs.
Is the new broadcasting standard expensive?
No, now DVB-T2 TVs and set-top boxes are no more expensive than old standard equipment. In addition, remember - federal multiplexes are guaranteed free of charge for the population of Russia, unlike cable, satellite or Internet television. Price necessary prefix starts from 1300 rubles.
How to set up a TV to receive a signal in the DVB-T2 standard?
First of all, you should read the instructions for your TV and / or digital set-top box to connect the equipment. Also, you may need to activate the digital tuner of your TV (by selecting the country in the appropriate section of the settings menu - Poland, Lithuania or Germany). Then you should run automatic search channels - in most cases, the built-in signal level and quality indicator will allow you to optimally tune your antenna for receiving digital television.
If you require manual setting digital TV channels, then use following settings: the first multiplex is broadcast on 47 TVK, frequency 682 MHz, the second multiplex - on 30 TVK, frequency 546 MHz (RTPS Kaliningrad).
What channels can be watched in the DVB-T2 standard?
Now two multiplexes (packages) are being broadcast in the Kaliningrad region: RTRS-1 and RTRS-2.
The first multiplex, broadcast simultaneously from five transmitting stations at a frequency of 682 MHz, includes channels: Channel One, Russia (Russia-1), Russia-2 (Russia-2, sports channel), "NTV", "Petersburg - Channel 5", "Russia - Culture" (Russia-K), "Russia-24" (Russia-24), "Carousel", "Public Television of Russia", "TV Center".
The second multiplex, broadcast from a transmitting station in Kaliningrad at a frequency of 546 MHz, includes the channels: Ren-TV, Spas, STS, Domashny, TV3, NTV Plus Sport, Zvezda, Mir", "TNT", "Muz TV".
DVB-T2 is arguably the most advanced digital terrestrial television system in the world today. In this article, we will try to figure out how the DVB-T2 standard managed to take a leading position in the global digital broadcasting market, as well as what advantages it has compared to its predecessor, the DVB-T standard.
What is DVB-T2?
The DVB-T2 standard is the most advanced digital terrestrial television (DTT) system in the world. It is characterized by greater stability, flexibility and at least 50% greater efficiency than all other DTT systems. This standard supports broadcasting in SD, HD, Ultra HD formats, broadcasting mobile TV, as well as any combination of the above formats.
origins
At one time, the DVB-T standard became the most widely used in the world. Since 1997, when it was officially approved as a valid one, more than 70 countries around the world have deployed DVB-T broadcast platforms, and today 70 countries of the world have already started launching multiplexes in the DVB-T2 system or have officially approved this standard.
With the transition of European countries from analogue to digital broadcasting and the growing scarcity of the frequency spectrum, the DVB concern outlined the general commercial requirements for the developers of an updated version of the standard, which was supposed to provide even more effective use frequency resource. DVB-T2 system could without special problems to meet all these requirements, including increased capacity, reliability and the possibility of further use of existing antennas. The first version of the DVB-T2 standard was approved in 2009 (version EN 302 755), and in 2011 an improved version of the system appeared, which, in particular, includes a new sub-standard T2-Lite, designed for the needs mobile broadcast and receiving a TV signal on portable devices.
How it works?
The DVB-T2 standard, like its predecessor, uses OFDM (orthogonal multiplexing) modulation. frequency division channels) with multiple subcarriers capable of transmitting stable signal, and also has a large number of different modes making this standard extremely flexible. The DVB-T2 system uses the same type of error correction coding as used in DVB-S2 and DVB-C2 systems: it is a combination of LDPC (Low Density Parity Check Code) and BCH (Bose-Chowdhury-Hawkvingham) coding types. ), providing high signal stability. In doing so, the system allows the number of carriers, guard intervals, and pilots to be varied, making it possible to optimize the overhead for any particular transmission channel.
The DVB-T2 system also uses additional new technologies, in particular:
- The use of several physical layer channels allows you to separately adjust the stability of each of the transmitted programs within the channel to adjust to the required reception conditions (for example, indoor antenna or external antenna). Besides, given function allows the receiver to save power by decoding only specific program from the multiplex, and not the entire transmitted packet as a whole.
- Alamauti coding, which is a transmitter diversity technique. Allows you to improve the quality of coverage in small single-frequency networks.
- Constellation Rotation feature for reliability when using low-order constellations.
- Extended interval feature including bit, time, cell and frequency intervals.
- Future Framework Extension Function (FEF) - allows future enhancements to the standard while maintaining compatibility.
As a result, a DVB-T2 system can offer much higher data rates than DVB-T, as well as greater signal stability. For comparison, the bottom two rows in the table show maximum speeds data transmission at a fixed signal-to-noise ratio and the required signal-to-noise ratio at a fixed (useful) data rate.
T2 Lite
The T2-Lite subsystem was the first additional profile in the standard, which was added due to the existence of the FEF principle. This profile was officially introduced in July 2011 to support mobile broadcasting and reception on portable devices, as well as reduce the cost of implementing these types of broadcasts. New Profile is a subsystem of the DVB-T2 standard using two additional speeds LDPC encodings. Due to the use in the subsystem of only elements related to reception on mobile and portable devices, as well as limiting the data transfer rate to 4 Mbps per physical layer channel, the complexity of creating and implementing a new chipset was reduced by 50%. Using the principles of FEF allows you to transfer in one frequency channel programs in T2-Lite and basic T2 even when the two profiles have different Fast Fourier transform (FFT) scores or different guard intervals.
Market Conquest
As in the case of DVB-T, the new standard was intended not only for transmitting programs to devices equipped with external or indoor antennas, but also for receiving on PCs, laptops, car TVs, radios, smartphones, dongles, and other innovative receivers . In countries where DVB-T platforms were already operating, DVB-T standards and DVB-T2 usually continue to coexist for some time, and in those countries where as such digital broadcasting was not, there is unique opportunity go directly from analogue broadcasting to digital standard DVB-T2, bypassing the DVB-T implementation phase.
Currently available on the world market great amount DVB-T2-compatible set-top boxes and TVs, while prices have already dropped to $25 for the most cheap models. The price difference between DVB-T and DVB-T2 compatible TVs is no longer significant.
The first country in which the implementation of digital broadcasting in the DVB-T2 standard began was the United Kingdom, where DVB-T2 broadcasting was launched in March 2010 in parallel with existing DVB-T platforms. During 2010-2011, DVB-T2 platforms were launched in Italy, Sweden and Finland, and very soon broadcasting in this standard was organized at the national level in each of these countries.
In Ukraine, the launch of on-air digital broadcasting in the DVB-T2 format began in autumn 2011. The company "Zeonbud" was engaged in the construction of a network of on-air transmitters. In January 2012, the on-air digital signal was encoded by the system conditional access Irdeto Cloaked CA. In this regard, the market for receiving equipment was limited, and following the results of tenders held in April and July 2012, two companies became the main suppliers of digital set-top boxes - Strong and Romsat.
However, in July this year, the National Council for Television and Radio Broadcasting, in its new composition, turned the country's digitalization process 180 degrees, obliging the provider national network on-air digital broadcasting "Zeonbud" disable signal coding. Thus, the introduction of the DVB-T2 standard on the territory of Ukraine acquires a new color, and, most likely, in the near future the television market will be filled with digital television receivers affordable price, which in fact will stimulate the interest of the population in a new type of television, and will also allow the country to fulfill its obligations to switch to digital by July 17, 2015.
Note that paid DVB-T2 platforms have also been launched outside of Europe. For example, in Zambia, Namibia, Nigeria, Kenya and Uganda, and in a number of other countries, the launch of broadcasting in this standard expected in the very near future. In many parts of the world, there is currently test broadcast in this standard, and many countries are considering adopting DVB-T2 as the standard for digital terrestrial broadcasting.
Seal
This is not a very common malfunction, and you can’t call it a malfunction either, meaning when the quality of the received DVB T2 signal jumps. Most often this is due to the position of the cable from the antenna to the TV, reception conditions and a number of other reasons. Why this happens is simply incomprehensible to an inexperienced user in such matters, and he can explain this behavior of the tuner by a malfunction of the set-top box or antenna, but this is not the point. However, let's go in order.
Causes
With what intensity does it jump dvb signal-t2, depends on the height at which the cable has such a horizontal section and how long it is, if it is located near the ground itself, then the effect of interference is minimal. It is clear that the longer such a section, the stronger the useful signal will be suppressed. To avoid this, place the antenna close to the set-top box, using a quality cable also helps.
The digital TV signal also starts to jump when it is tilted, for example, when it goes down from the roof ridge to the wall. It is worth noting that there is a known case when, with an inclined cable, the receiver after tuning showed quite long time, and with the onset of summer and hot weather, the signal level began to jump from 0 to 100, and the quality signal was kept at 5%.
There have been cases in practice when in urban conditions, with a nearby tower, an active indoor antenna was used to receive the first and second multiplex. The signal arriving at the tuner was very large, which led to the protection operation and, as a result, the signal began to jump on the digital tuner.
There were also reverse cases when the signal was artificially lowered. This refers to barriers in the form of buildings or trees. Moreover, if there is a tree between the antenna and the tower, the reception is excellent in winter, and in summer the foliage dampens the signal and there were also jumps in its level. AT this case enough to move the antenna. By the way, for this reason, there is a signal disruption on satellite TV, plate set for several years regularly showed and suddenly failures began to occur, the picture crumbles into squares. It turned out that the tree had grown over the years and began to close the dish from the satellite.
There are many nuances here and they can have an impact - the weather, the quality of the cable, the distance of the tower (signal strength), so you need to figure it out in each case when the signal starts to jump when receiving or setting up t2, and it doesn’t matter what set-top box you have world vision, Rolsen, etc..
Avoid twisting the wire into a coil, as well as long sections with a horizontal and inclined position of the cable, use in these cases.
To avoid interference, the cable must be placed away from power electrical wires and avoid crossing the cable with power lines, and when crossing, make it at a right angle.
Carry out the TV cable in whole pieces, if breaks cannot be avoided, then use special connectors with reliable wire contact and shielding, and not twisting with electrical tape.
