Modern TV standards (NTCS, SECAM, PAL) have existed for several decades and, it would seem, should be improved, but since these are analog systems (i.e. the viewer sees an electrical analogue of the image), their further development is limited. The fact is that at each section of conversion and transmission of an analog signal, distortions occur, which, overlapping each other, degrade the quality television image. For example, a powerful electric motor operating close to a television receiver can create significant interference on the screen.
The analog signal is continuous, and to convert it to digital form, it is divided into separate samples spaced at the same time interval (signal sampling). When digitally encoding a signal, a special encoding device - an encoder - is able to sort out a clean signal from industrial and atmospheric interference, therefore the stability of the TV system parameters increases, however, the amount of information about the brightness and color of the signal increases sharply. That is why, until recently, digital signal transmission seemed unfeasible, although the key to solving this Herculean task was founded in the works of the American engineer Claude Chenon (1916-2001) back in 19481. The theory of information he proposed substantiated the redundancy of the source of messages.
Each trdlbvy stdnt mzht sdt thnk SM, for bzdlnk this slzhn.
If you succeed, you can conclude that vowel sounds are redundant information.
By the way, one of the first alphabets - Ugaritic (2nd millennium BC) - did without vowels. Note that in this case we compressed analog information. Now let’s imagine that a journalist is filming a bird soaring in the sky: it is moving, but if we mentally break this image down into the smallest dots, it turns out that most of the information does not change (remember the ancient philosophers - “a flying arrow is at rest”). Indeed, the color of a bird is constant; If the sky is cloudless, it is difficult to distinguish one part of the background from another, and only during flapping of the wings will the information about the geometric points of the image change.
If each minimal point on the screen (pixel) is described by a combination of numbers, for example, 1100, and the number of such points is ten, you can create a digital chain:
1100 1100 1100 1100 1100 1100 1100 1100 1100 1100, or you can write it shorter, i.e. compress using basic arithmetic: 1100x10.
It follows that digital information You can compress quite effectively using not only the simplest arithmetic operations, but also the most complex mathematical algorithms, which, of course, we will leave outside the scope of this publication. So, when transmitting a digital signal, there is no need to transmit the entire image frame by frame (as in cinema), only difference (changing) information can be transmitted. Thanks to modern methods With the compression of digital data, the bandwidth of the video signal has narrowed significantly, and several digital channels can be located in place of one analog channel.
In the USA, in 1996, the digital TV standard - ATSC was adopted, and individual television centers began broadcasting in digital format, and from 2006 it is expected to stop analog TV broadcasting, with the caveat that until 85% of the viewing audience is ready to accept digital signal, analogue broadcasting will remain. the main problem the introduction of “digital” is that the majority of television receivers among the population around the world are analogue. Either they need to be replaced with digital ones (at the expense of the TV viewer), or the population must be provided with special set-top boxes that can convert the received digital signal to analog (the Russian company NTV-Plus has taken a similar path). A modern digital television receiver is a rather expensive device, so during the transition period, it will most likely be provided technical feasibility reception of a digital signal by a regular TV.
High Definition Television (HDTV)
Advantages digital coding in television are obvious: even when receiving “digital” on a regular TV, the image quality increases due to the absence of distortion on various stages television path. In this case, the beam scan remains interlaced and the screen resolution does not increase. For essential
To further improve the quality of television images, it is necessary to introduce new standards for the formation and reception of video signals; such a system is high-definition television (HDTV). The American standard (ATSC) is designed for viewing the program both on a television screen and on a computer monitor. Wherein high quality Pictures can only be obtained on the screen of a special widescreen TV with 1080 active lines, interlaced scanning.
According to the ATSC standard, each TV receiver must decode any of the numerous (18 varieties in total) ATSC formats and output it exactly in accordance with the capabilities of the particular connected receiver.
Externally, a digital HDTV receiver differs from an analogue one in that it has a wider screen: if the aspect ratio of a regular TV is 4:3 (width to height), then in the digital version it is 16:9. The quality of the television image is noticeably improved by doubling the expansion lines and progressive scanning (however, scanning can also be interlaced). With progressive scan, screen brightness can be increased by 40%. The number of reproduced details on the screen increases several times. The new system has expanded the frequency of the luminance and color difference signals, so color reproduction is optimized. A multi-channel sound transmission system allows you to achieve the effect of presence, since audio information comes to the viewer from different sides.
The introduction of HDTV requires an expensive modernization of the hardware and studio complex, but broadcasting practice in the USA has shown that even today the number of HDTV programs in the total time of digital TV is constantly growing.
TV screens
Currently, the most common models are those with cathode ray tubes, they reproduce color shades well, but have significant flickering and rather large dimensions in depth. The bulkiness is due to the fact that the distance from the electron gun to the screen must be proportional to its size. Some companies have begun producing monitors with a curved electron beam path in a CRT. Perhaps this will make it possible to bring the gun significantly closer to the screen, thereby almost halving the depth of the tube. Screen flickering has a harmful effect on vision, so it is recommended to watch them in combination with “hygienic light” (diffuse daylight or incandescent lamps that significantly exceed the frequency of screen flicker). In addition, the viewer is in the field of action of currents ultra high frequency(microwave).
The next generation of screens is based on changing transparency liquid crystals under the influence of an electric field. Such monitors are called liquid crystal monitors. They are lightweight and have dimensions in thickness, but most importantly, they completely eliminate the influence of microwaves and flicker. At the same time they have significant shortcomings: color rendering is inferior to this parameter of screens with cathode ray tubes, and a viewer looking at the monitor at a different angle sees a degraded image. The small viewing angle creates problems for increasing the screen size. Nevertheless, the technology is improving, and the diagonal of modern liquid crystal monitors has exceeded one meter.
The most expensive are plasma screens. They are flicker-free, have a minimum size in depth, the image has the same clarity throughout the entire working field, plus they are easily scaled. Plasma panels are called because high voltage is applied to each pixel of the screen, under the influence of which the gas (xenon) turns into a state of cold plasma. New TV receivers will most likely be equipped with all of the above types of screens, but most importantly, they must be universal and suitable for use in all countries of the world.
Surround TV
From a theoretical point of view, achieving the effect of a three-dimensional image is quite simple: it is enough to take two television cameras, place their lenses at points corresponding to the distance between a person’s eyes, and then ensure separate vision of the captured images by the right and left eyes, since a person receives a relief vision of the world by examining objects two eyes (binocular vision). If you look at an object with one eye (monocular vision), the distance of objects from each other is determined less accurately.
In our country, theoretical developments in the field of stereo television began back in 1949 under the leadership of Professor P. V. Shmakov in Leningrad, and already in 1950 a stereoscopic installation was created. Developments in color stereo television are associated with expanding the frequency spectrum of the transmission channel: since color video information is transmitted by three signals (one luminance and two color difference), then for stereo images it is necessary to use six signals (three for each eye). To narrow the frequency spectrum, our scientists began to transmit video information for one of the eyes in black and white, and for the other in color, while the viewer saw a full color picture, since the brain determined the overall quality based on the best image.
To view information separately with the right and left eyes, you can use special glasses with color filters (anaglyph separation) or use an optical raster. The ease of using glasses is not controversial from a medical point of view: the eyes become very tired, since the lens of the eye cannot refocus from near objects to distant ones. The use of an optical raster significantly complicates the creation of a television receiver.
In the early 1980s. In Germany and Japan, experimental stereoscopic transmissions with anaglyph separation were carried out, and later a raster system was tested in the USA. There are many problems on the way to the introduction of stereo television, but one of the significant ones is the same as at the dawn of the introduction of color TV - the ability to receive video images on the receivers available to the population.
Developments in the field of three-dimensional television by introducing a range signal (RGBD - D from English distance) next to color signals are worthy of attention. Infrared laser ray When shooting, it “measures” the distance to each object.
Specialists different countries Research is being conducted in the use of multi-angle and holographic television, some of them even believe that with the help of TV in the future it will be possible to transmit not only visual volumetric information, but also odors, since it is known that odorous substances affect the olfactory epithelium, and its surface becomes electronegative with respect to the rest of the tissue. If indeed our brain determines odors due to the effect of electrical discharges on individual cell receptors, then technical point vision, the transmission of smell is feasible: after all, television became possible thanks to the conversion of light into electrical signals, and radio - the conversion of sound into electrical signals.
The writing of this article was partly dictated by technical progress and the development of the audiovisual industry, which has finally swept our country. There is also a need to clarify what digital terrestrial television is and what advantages it gives the subscriber.
Glossary
Multiplex- (plastic bag television channels(services)) - a list of television channels and radio channels, television and radio broadcasts of which are carried out using one radio frequency channel;
RTRS-1– a package of ten channels. According to the Presidential Decree Russian Federation dated June 24, 2009 No. 715, No. 456 dated April 17, 2012, No. 167 dated April 24, 2013. mandatory public TV channels are: Channel One, “Russia 1”, “Russia 2”, “Russia 24”, “Culture” ", NTV, children's and youth television channel, "Channel 5. St. Petersburg", OTR, "TV Center - Moscow"
RTRS-2- package of ten channels. Formed in accordance with the decisions of the Federal Competition Commission for Television and Radio Broadcasting dated December 14, 2012 and December 18, 2013. Package contents: “REN TV”, “SPAS”, “STS”, “Domashny”, “TV-3”, “Sport Plus”, “Zvezda”, “Mir”, “TNT”, “Muz TV”
DVB (Digital Video Broadcasting)- common open European standard digital transmission multimedia adopted by the European Broadcasting Union ETSI (European Transmission Standards Institute) and ensuring high quality broadcasting.
DVB-T2- digital terrestrial standard television broadcasting, developed within the framework of the DVB project
The application of this standard is approved by the order of the Government of the Russian Federation No. 287-r and the decision State Commission on radio frequencies dated March 16, 2012.
DVB-T2- This last generation European standard terrestrial digital DVB-T television. The DVB-T2 standard increases the capacity of digital terrestrial television networks by 30% compared to the previous standard, with the same network infrastructure and frequency resources.
COFDM modulation - (Coded Orthogonal Division Multiplexing), modulation specifically designed to combat interference in multipath reception.
DVB-H– a version of the digital terrestrial television broadcasting standard designed specifically for mobile devices. differs from DVB-T in that it is optimized for mobile reception: the program is not constantly transmitted to the terminal, but in short packets, then the receiver turns off for a while and playback from the buffer occurs. This saves battery energy, and the system itself becomes less sensitive to interference.
ASO- (analog switch-off), the moment the last analog transmitter is turned off
According to the concept of the development of television and radio broadcasting in the Russian Federation in the coming years, a massive transition from analogue television broadcasting to digital, in the DVB-t standard, is expected. This is a version or “variation” of the DVB standard that describes terrestrial broadcasting.
First you need to decide on frequency range: unlike analog terrestrial broadcasting, which operates in the range 48 – 862 MHz (UHF and UHF), in digital terrestrial broadcasting the range is, as a rule, narrowed only to the UHF range: 470 – 862 MHz.
This requirement is dictated by a number of reasons: the very principle of digital terrestrial signal formation, the nature of radio wave propagation, optimal ratio signal attenuation and the power of transmitters and the size of receiving antennas.
Choosing the Right Antenna
Reception of digital terrestrial TV can be carried out using an existing antenna that received analog UHF signals. There is only one condition - reliable reception of the analog signal without interference; if the antenna was “so-so”, it must be replaced with a more efficient one. Losses in signal reception can also be caused by poor quality coaxial cable or connectors. Digital signal level terrestrial television may be lower than that of analogue, while the image on the TV screen looks much better: without noise, interference and interference often characteristic of conventional terrestrial TV.
Thus, at the first approximation, the end subscriber receives only the benefit:
Can be used indoor UHF antennas in the area of reliable reception
TV picture without interference throughout the entire reception area
Advantages of digital broadcasting: TV guide, stereo sound, etc.
However, there are some disadvantages:
The need for the subscriber to purchase a television set-top box
In the case of broadcasting only the first multiplex, it is possible to reduce the number of received channels
A number of questions also remain unresolved:
Will the signal from all multiplexes including the first one be encoded?
If yes, will there be a system conditional access“addressed” as in the case of Tricolor TV?
Will the second multiplex be paid?
Which court will be used to protect the content?
Alexey Malinin, CEO RTRS in its interview with the socio-political magazine “Itogi” says:
- Has any decision been made at the state level yet?
- Definitely - no. My personal opinion: the second multiplex should be equally accessible to the citizens of our country and have the same distribution area as the first multiplex. And that's why. There is no doubt that it will have a serious regional component within it - both the President of the Russian Federation and the Minister of Communications spoke about this - that is, broadcasting will remain regional companies, which insert into the air of central channels. I think it would be fair if part of the costs of distributing this package of channels throughout the region, territory, republic and constituent entities of the Federation would be borne by the regional authorities. Thus, they would take on the same obligations in relation to the region as the federal government did in relation to the first multiplex.
Some will ask: what is all this for? After all, everything is shown so well at my dacha?
Digital terrestrial TV has a number of advantages over analogue.
Mobility.
High picture quality and soundtrack. (if you're lucky - depends on the broadcaster)
The required signal level for high-quality viewing of TV channels in digital format is lower than in analogue. In other words, where analog TV will come with noise and interference, the digital signal will pass through in the quality in which it is generated in television studios.
Increase in number transmitted channels at the frequency of one analog channel (bandwidth 8 MHz) through the use of the MPEG-4 compression format.
Simple and fast connection. (in most cases, a UHF antenna is sufficient)
Additional services (TV guide, digital stereo sound, etc.)
In which regions? When?
According to the resolution of December 3, 2009 No. 985 On the federal target program “Development of television and radio broadcasting in the Russian Federation for 2009 - 2015”
Http://government.ru/gov/results/8562/
The regions of the 1st stage of creating digital television broadcasting networks (2010) included 12 regions, 2089 broadcasting points, with a funding volume of 2862 million rubles, in particular:
Republic of Altai, Republic of Buryatia, Republic of Tyva, Republic of Khakassia, Altai region, Trans-Baikal Territory, Kamchatka Territory, Primorsky Territory, Khabarovsk Territory, Amur Region, Sakhalin Region, Jewish Autonomous Region.
The regions of the 2nd stage of creating digital television broadcasting networks (2011 - 2012) are 27 regions, 1554 broadcasting points, with a funding volume of 3299 million rubles, in particular:
Republic of Adygea, Republic of Dagestan, Republic of Ingushetia, Kabardino-Balkarian Republic, Republic of Kalmykia, Karachay-Cherkess Republic, Republic of Karelia, Republic of North Ossetia - Alania, Chechen Republic, Krasnodar Territory, Astrakhan Region, Belgorod Region, Bryansk Region, Volgograd Region, Voronezh region, Irkutsk region, Kaliningrad region,
The regions of the 3rd stage of creating digital television broadcasting networks (2012 - 2013) are 39 regions, 1582 broadcasting points, with a funding volume of 4286 million rubles, in particular:
Komi Republic, Mari El Republic, Mordovia Republic, Tatarstan Republic, Udmurt republic, Chuvash Republic, Perm Territory, Stavropol Territory, Arkhangelsk Region, Vladimir region, Vologda region, Ivanovo region, Kaluga region, Kemerovo region, Kirov region, Kostroma region, Kurgan region, Lipetsk region, Magadan region, Moscow region, Nizhny Novgorod region, Novgorod region, Novosibirsk region, Omsk region, Oryol region, Penza region, Ryazan region, Samara region, Saratov region, Sverdlovsk region, Tambov region, Tver region, Tomsk region, Tula region, Ulyanovsk region, Chelyabinsk region, Yaroslavl region, Moscow, Nenets autonomous region.
The regions of the 4th stage of creating digital television broadcasting networks (2013) are 5 regions, 1275 broadcasting points, with a funding volume of 1549 million rubles, in particular:
Republic of Bashkortostan, Republic of Sakha (Yakutia), Krasnoyarsk Territory, Chukotka Autonomous Okrug, Yamalo-Nenets Autonomous Okrug.
Preparations for the transition to digital terrestrial broadcasting in the region include:
Development of a system design for a digital television broadcasting network in the region; commissioning by the telecom operator of the digital broadcasting network of the 1st multiplex with broadcasting coverage equivalent to the analogue broadcasting area in the region
But how is everything going in reality?
Leading procurement manager of the company supplier and developer of broadcast digital equipment, Alexander Petrov, agreed to answer several questions:
- Which regions have actually already started broadcasting?
- In the Russian Federation there are 2 ways to switch to digital broadcasting: the first is a federal digitalization program at the expense of the federal budget, while in most regions projects have been created in such a way that in the event of an increase in services there is no need to re-equip antenna-feeder systems. But some regions have already launched broadcasting on their own without waiting for funding - for example, Kazan and Yekaterinburg. (second path of digitalization)
- Is anyone working ahead of schedule?
- IN currently In 81 constituent entities of the Russian Federation, network construction has been completed or begun. And in the 80s, digital broadcasting of the RTRS-1 digital TV channel package (the first multiplex) began. Of the 83 constituent entities of the Russian Federation, only two subjects are just preparing to begin construction. These are the Republic of Bashkortostan and the Yamalo-Nenets Autonomous Okrug.
To date, 2,634 facilities have been put into operation.
In several regions, broadcasting began a long time ago and is indeed noticeably somewhat ahead of schedule. For example, in St. Petersburg already in 2003 they broadcast digital services at a frequency of 34 channels. Currently in St. Petersburg and Leningrad region have been broadcast for two years now digital channels DVB-T2.
Regions also included in the first stage Far East, for example the Jewish Autonomous Region.
Experience in introducing digital television in Spain:
Let us turn to the experience of Spain, a country that already completely switched to digital broadcasting in 2010:
Kantar Media/TNS Sofres, provided information on the development of digital technology. According to the agency's figures, 2009 started with only 43.7% of all Spanish households ready to receive terrestrial digital television. The concept of readiness meant that the household was in a digital broadcast zone, the building was equipped with an antenna capable of receiving a digital signal, and there was at least one audiovisual device. However, by March this figure exceeded 50%, and by the end of the year, 77.4% of all households were covered by the new technology.
During the transition, it was noted that consumers were in no hurry to acquire a digital tuner. Spanish government agencies it was necessary to carry out a lot of outreach work in regions where it was planned to turn off analogue television in order for the population of these regions to take care of purchasing an external tuner (set-top box). This is evidenced by the fact that, according to GfK R&T, demand for external tuners was sluggish until the analogue TV shutdown deadline approached, at which point external tuners began flying off the shelves like pies. This trend demand was registered in all regions.
Since 2007, sales of televisions and DVD players equipped with a built-in tuner have steadily increased compared to sales of external tuners. That same year, integrated digital tuners began to dominate as a type digital receiver purchased by Spanish households. At the end of 2009, 61% of all decoders purchased by the population were integrated. Of these, about three-quarters were tuners built into flat-screen TVs. In 2006, televisions with built-in digital tuners accounted for about 16% of all televisions purchased, in 2008 their share exceeded 50%, and in 2009 it was 98%. In the process of replacing televisions with an analogue tuner with televisions with a digital tuner, a decisive role was played by both the corresponding proposals of manufacturers and informed demand, because since 2008, labels on video equipment were required by law to contain information about the presence of a built-in digital tuner. In January 2010, the number of digital receivers purchased by the Spanish population exceeded 27 million, according to GfK, and the percentage of those connected to DVB-T in Spanish homes was 80.8% (
For the first time in Russia, experimental digital broadcasting according to the European DVB-T standard began on July 2, 2000 in Nizhny Novgorod. Since then, digital terrestrial television broadcasting, the need and prospects of which have recently been talked about more and more often, is gradually but confidently making its way onto the airwaves. `Media News` decided to cover this topic in more detail and talk about what awaits our country with the advent of the digital era.
By 2015, Russia must switch to a system for broadcasting television signals in digital format. The program “Development of Television and Radio Broadcasting in the Russian Federation” (2007-2015), which is currently being prepared at the state level, implies that analogue broadcasting will be completed by 2015. The entire national system will become digital broadcasting. `The transition to digital broadcasting is a global trend in the development of telecommunications. Digital algorithms signal processing allows you to solve applied problems, expand the range of services provided, improve the quality of television image and sound,” notes Alexander Tepper, General Director of KOSMOS-TV CJSC.
For Russia, the issue of introducing digital terrestrial television broadcasting is truly important and relevant. And this is due not only to the fact that the whole world is switching to digital, but also to the need to solve internal problems related to the prospects for the development of domestic television.
The main difference between the principles of building television broadcasting networks in Russia and foreign countries is the predominance of analogue broadcasting against the backdrop of insignificant distribution and slow development paid systems cable and satellite television. However, traditional analog television has practically exhausted its capabilities. According to experts in our country, up to 80% of transmitters are almost completely worn out, and in the near future there may be a massive blackout of television broadcasting in the regions. However, it makes no sense to replace outdated analog transmitters with similar ones. It would be more correct to install digital equipment, not only from the transmitting side, but also from the receiving side, i.e. on the part of consumers. Another, no less important reason pushing for the speedy introduction of digital television technologies is air pollution. With the development of new types of communication, the level of interference has increased significantly, and the digitization of transmissions can be a solution to this problem. Everything suggests that television needs a new qualitative leap. And the introduction of a digital terrestrial broadcasting system seems to be one of the most likely solutions to the accumulated problems.
`When we talk about digital television, we first of all talk about the fact that the signal delivery technology will simply change. Nothing else significant will happen from the viewer's point of view, practically nothing will change at all. The TV worked the way it worked, so it will work,” says Aleksey Efimov, director of international broadcasting at Channel One. - The only question here is what will change technical method signal delivery. The main thing that digital television will bring us is that the capacity will increase, which will be capable of broadcasting much more large quantity TV channels. Depending on what technology is chosen, there will be tens of times more channels than now.
This is a completely natural process, because if we look at Western countries, then today we can already see that there are hundreds of television channels in the states, and in Russia you can still count them on one hand. This will be a plan - on the one hand, a change in technology, on the other hand, an increase in the number of channels that will be available to the viewer. This is what will await us in the era of digital television.
As for the number of channels, there will be many of them, they will compete with each other, but each of them will compete in a specific niche. Naturally, there will be federal channels intended for everyone, such as there are now - “First”, “Russia”, “NTV”. In addition, there will be competition between the so-called thematic channels, which are dedicated to a specific area of viewer interest - car channels, weather channels, movie channels.
Digital DVB-T Broadcasting has a number of undoubted advantages. Firstly, it saves frequency and energy resources. It becomes possible to transmit more than four television channels on one frequency and, therefore, free up new frequencies for new media. Secondly, this is the construction of single-frequency broadcast networks (SFN), which, as world experience shows, helps to expand the audience of television viewers and cover large areas without losing the quality of transmitted programs. Thirdly, this is the development of new technologies, the implementation of the idea of multi-purpose interactive television, the creation of a unified digital data transmission platform, etc. Digital television is single network, which allows you to enjoy not only a beautiful picture and high-quality sound, but use interactive television services, as well as connect to all services that operate via cable connections, for example, the Internet, security and fire alarms.
“The transition to new technologies is a natural evolutionary process,” says Alexey Efimov. - Technical experts can say that digital TV is about quality, but, in fact, for the average viewer this parameter will be almost invisible, because with the ordinary eye you and I will not see much difference between the picture of analogue and digital television.
On the other hand, high-definition channels will appear, the so-called High Definition. This is where the difference will be visible, of course.
For channels, the transition to digital will mean a reduction in costs for communication services, since digital technology signal transmission is much less expensive. Costs will decrease several times compared to analog TV, this is very significant for the economics of channels. And, of course, channels get the opportunity additional services- such as closed captioning, electronic program programs, teletext. All this is possible with digital technology.
But, despite all the advantages of digital terrestrial broadcasting and the desire to keep up with others, it is impossible to switch from “analogue” to “digital” overnight, turning off one broadcast and turning on another. This is a complex process, not only from a technical and economic point of view, but also from the point of view of public perception, a process that requires reasonable approaches and tactically correct decisions.
According to analysts from the Informa agency, the number of digital television subscribers worldwide will reach 500 million by 2011. By that time, about 60% of the population will still receive an analog television signal. Now digital television is confidently gaining momentum. There are already about 183 million subscribers, reports BBC News. Digital TV signals are transmitted via cable broadband networks, satellite and terrestrial broadcasting. According to statistics, in 2006 the number of subscribers increased by 40 million, and in 2007 there will be another 46 million more. And primarily due to the residents of North America and Western Europe. China is also making its contribution to the development of digital television. The USA, India and Japan are doing well in this area. About 60% of the total number of digital homes are located in these four countries.
The UK is among the world's fastest growing digital TV customers. European countries. Already, about 72% of houses there are equipped with digital television receivers. Interestingly, analogue television will be switched off completely in some British cities next year. Process complete transition digital TV in this country is planned to be completed in 2012, analysts report.
It is no secret that the digital broadcast format brings improved picture and sound quality to the viewer, reliable protection from interference, a significant increase in the number of channels. With digital TV come some useful services, for example, TV on demand (TV on demand). HDTV also fits perfectly into the digital broadcasting landscape. When it comes to high-definition television, the United States is one step ahead of other countries. In Europe, the introduction of high-definition TV is progressing at a much slower pace. However, after the matches of the last World Cup were broadcast on HDTV, European interest in the new format has grown significantly.
If we talk about the distribution of HDTV services in our country, then according to various estimates, from 3 to 5 thousand subscribers have access to them, both in commercial and test mode, mainly satellite TV subscribers. According to market participants, by 2007 Europe will account for 7% of HDTV subscribers from total number pay TV subscribers, and by the end of 2008 - 12%. Russia has every chance to achieve these same indicators. Almost all cable networks broadcasting in the DVB-T digital standard are capable of technical problems transmit HDTV programs.
All previous decades of television were the period of analog television. As technology developed, a number of shortcomings were discovered that limited its further development. Among the reasons limiting the development of TV image quality is the poor noise immunity of the analog signal.
It is possible to improve the quality of television programs when transmitting them over long distances using a fundamentally new method - digital. Further improvement of color TV's coming towards the widespread introduction of digital methods of signal processing, management and monitoring of their operation.
Among the most significant advantages digital way transmission should include the possibility of obtaining a high-quality television image due to the virtual absence of signal shape distortion and increased noise immunity and simplified exchange television programs between countries that have different standards.
Digital signals have many advantages, but working with them requires completely new technical means. Therefore, the transition is carried out gradually, in several stages.
At the first stage, i.e. Already today, some blocks are being replaced analog TVs digital. The functions performed by digital devices provide improved image quality.
Implementation digital devices at this stage practically does not change functional diagram- it will simply be present at the input and output of the digital block analog signal.
The second stage is of no interest to consumers, since it will only affect the transferring party. At this stage, only the television center complexes will become digital.
The third stage will be characterized by the creation of fully digital telecentres. However, the signal at the output of the television center will remain analog, since the fleet of televisions will not yet be digital.
The fourth and final stage will be characterized by the creation of fully digital television receivers. Digital home TVs, which will appear in the near future, will turn into devices that allow feedback from video information sources: computing center, help desks, libraries, etc.
There is no high-definition television system adopted as a single System in the world today. Existing color television systems SECAM, PAL, NTSC, operating in line decomposition standards and with frame rates of 625/50 and 525/60 and with a 4:3 frame format, are two to three times inferior to the image quality on a movie screen.
The need to improve quality has led to the need to create high-definition television systems - High Definition Television (HDTV).
High-definition television must transmit and reproduce an image that is completely or almost identical in quality to the original. In 1990, the CCIR adopted recommendations on parameters unified system HDTV. They contain a proposal to develop a digital HDTV system with progressive scan, 16:9 format, and the number of samples 1920 per line.
Before the completion of work on the development of HDTV, the world's leading television companies began to improve existing systems. The result was the PAL-plus and SECAM-plus systems. They were developed by GRUNDIG, NOKIA, PHILIPS and THOMSON.
Digital television is a new generation of television technology in which the transmission, processing and storage of a television signal are carried out in digital form. Compared to analog television, the use of digital TV methods and means provides a number of advantages. They are:
In a significant increase in the number of television programs transmitted in the same frequency range;
In increasing the noise immunity of transmission and recording paths of television signals;
In improving picture and sound quality in television receivers with the usual standard of decomposition;
The possibility of creating television systems with new resolution standards (high-definition television);
The possibility of creating interactive television systems;
In transmitting various additional information in a television signal, turning a television receiver into a multifunctional information system.
The listed possibilities are due both to the principles inherent in digital television and to the presence of various algorithms, circuit solutions and a powerful technological base.
In May 2004, the Russian government recognized it expedient to introduce the European digital television broadcasting system (DVB - Digital Video Broadcasting) in Russia. Now in trial mode Digital broadcasting is carried out in Moscow, St. Petersburg and Nizhny Novgorod. The Ministry of Information Technologies and Communications announced its intention to ban the import of analogue televisions and stop their production in Russia in the coming years. The complete transition to digital TV is planned to be completed by 2015.
Russian television producers have not become pioneers in this area; in many countries there is already a massive transition to digital. In October 2005, the US Senate approved a bill according to which in 2009 analogue television in the United States will be completely replaced by digital television. The UK began to reduce the share of analogue equipment back in 1998, and today more than 73% of British households are able to receive a digital signal. In Japan, digital broadcasting will cover all major cities by the end of 2006, and, according to the order of the Ministry of Internal Affairs and Communications, special labels are already attached to all analogue televisions going on sale, warning buyers that from July 2011 analogue television and radio broadcasting in the territory there will be no country.
What caused such active steps to introduce digital television broadcasting? First of all, the fight for the viewer. Digital television provides much higher quality standard definition pictures and the ability to broadcast TV programs in high definition format with multi-channel sound.
Frequency deficiency also plays a role. Almost the entire meter and most of the decimeter bands are already occupied. There are not enough frequencies for government agencies and companies providing wireless communications services. This problem was felt especially acutely by US police and rescue workers during the terrorist attacks of September 11, 2001 and the hurricanes that hit the country.
Digital technology makes it possible to increase the number of broadcast channels several times with the same signal bandwidth. This occurs due to compression of the information contained in the original video signal. Of course, some of the data is lost in the compressed signal, but the peculiarities of human vision and hearing do not allow us to notice the changes.
To receive a digital television signal, you need a special TV, but the one you currently have at home is also suitable if it is equipped with a set-top box decoder.
With the advent of digital television, feedback from broadcasters to viewers will be simplified. Already today on Russian television channels there is a tendency to involve viewers in what is happening on the screen. They are invited to take part in polls, surveys, competitions, for which they should call the phone number indicated on the screen or send an SMS message. In the future, it will be possible to send a message using only the remote control, using back channel- from those through which communication with the Internet is currently carried out (city telephone network cable, ADSL line, leased line or cellular). You can receive additional information, vote, purchase goods and services, and even communicate with other viewers without interrupting your viewing of programs.
Already today, customers of digital TV operators can enjoy all its benefits. The rest can only wait - just a little.
The so-called computer vision is becoming increasingly widespread in the world - a kind of centaur with a television screen instead of a head and a computer instead of a torso. Now it is difficult to say what will more influence the inner world of the current younger generation - school education, educational programs of TV (and antenna, satellite, and cassette combined) or video games - one of the most promising sections of computer vision. But not only children are involved in electronic games. Special programs will teach you how to drive a car and an airplane, a nuclear power plant and a transnational company, and how to feel like you are in the chair of a president or commander in chief. The symbiosis of a television screen with a computer of the latest generation makes it possible to synthesize three-dimensional images, creating unprecedented opportunities for “business graphics” - machine design, especially industrial design. Experts call this new feature of the TV screen infographics.
Computer graphics have already taken a prominent place in the design of television programs. This is the real path to stereo television.
Television novelties should also include teletext, videotex, telefacsimile, and other personal information systems for consumers. All this is so-called captioned television. Videotex is a designation adopted in many countries around the world for interactive services - systems for transmitting information over the wires of the telephone network. It should not be confused with the term “videotext”, which means a method of transmitting text and graphic information over the air, via television channels, in parallel with regular broadcast programs. This method is called “teletext” throughout the world. Making a printed copy from a television image is called reprography.
The day is not far off when it will be possible to “meter out” the volume of scenes of violence and obscenity on the screen of your television set. San Diego-based Video Freedom believes that with the help of new technologies, the viewer will be able to easily and simply control the content of any program. A special system is capable of selecting shocking material in four categories: sex and nudism, violence, profanity. The viewer is given the opportunity to remove unwanted fragments within these four categories.
This latest marvel of television technology, still in the experimental stage, will serve those who are critical of individual television programs well.
The modern development of television is moving along the path of increasing massization of production and individualization of consumption. Undoubtedly, taking into account the specifics and capabilities of each type of television journalism, as well as the needs of the audience, which it identifies specifically with this function of the television screen, is a promising way of organizing activities and planning a system of information disseminated by audiovisual means.
