First steps towards knowledge. Stephen Gray (1670-1736)

The conductive structure consisted of a glass tube and a plug placed in it. As the tube rubbed, the cork began to attract small pieces of paper and straw. Gradually increasing the length of the cork by inserting wood chips into it, Gray noted that the same effect continued to the end of the chain.

By replacing the cork with a wet hemp rope, he managed to achieve a distance of transmitted electric charge of up to 250 meters.

But it was necessary to make sure that electricity was not transmitted under the influence of gravity in a vertical position, and Gray repeated the experiment, placing the structure in a horizontal position. The experiment was doubly successful, since it was found that this is not transmitted over land.

Later it turned out that not all substances have the property of electrical conductivity. In the course of further research, they were divided into “conductors” and “non-conductors”. As you know, the main conductors are all types of metals, solutions of electrolytes, salts, and coal.

Non-conductors include substances where electrical charges cannot move freely, such as gases, liquids, glass, plastic, rubber, silk and others.

Thus, Stefan Gray identified and proved the existence of such phenomena as electrostatic induction, as well as the distribution and movement of electric charge between bodies.

For his achievements and contribution to the development of science, the scientist was not only the first nominee, but also the first to be awarded the Royal Society's highest award, the Copley Medal.

On the way to isolation. Tiberio Cavallo (1749–1809)

A follower of Stefano Gray in the field of electrical conductivity research, Tiberio Cavallo, an Italian scientist living in England, developed a method for insulating wires in 1780.

Their proposed scheme consisted of the following sequence of actions:

1. Two stretched wires made of copper and brass must be calcined either in a candle fire or with a hot iron piece, then covered with a layer of resin, and then a piece of linen tape impregnated with resin must be wound on them.


2. After which it was covered with an additional protective layer of “woolen cover”. It was meant to produce such products in sections of 6 to 9 meters. To obtain greater length, the parts were connected by winding onto pieces of oil-impregnated silk.

The first cable and its application. Francisco de Salva (1751–1828)

Francisco Salva, a famous scientist and doctor in Spain, appeared before members of the Barcelona Academy of Sciences in 1795 with a report on the telegraph and its communication lines, in which the term “Cable” was first used.

He argued that the wires could not be located remotely, but rather they could be twisted into a cable, which made it possible to place it suspended in the air.

This was revealed during experiments with cable insulation: all the wires present in the composition were first wrapped in resin-impregnated paper, then twisted and additionally wrapped in multi-layers of paper. In this way, the loss of electricity was eliminated.

At the same time, Salva suggested the possibility of waterproofing, given the fact that the scientist could not know about the materials applicable for this type of structure.

Francisco Salva developed the project of overhead communication lines between Madrid and Aranjuez, which was carried out for the first time in 1796 in the world. Later, in 1798, the “royal” communication line was built.

Cable and wire products and accessories

History of the emergence and development of power lines in Russia

The first case of transmitting an electrical signal over a distance is considered to be an experiment conducted in the mid-18th century by Abbot J-A Nollet: two hundred monks of the Carthusian monastery, at his direction, took hold of a metal wire with their hands and stood in a line more than a mile long. When the inquisitive abbot discharged an electric capacitor onto a wire, all the monks were immediately convinced of the reality of electricity, and the experimenter was convinced of the speed of its propagation. Of course, these two hundred martyrs did not realize that they formed the first power transmission line in history.

In 1874, Russian engineer F.A. Pirotsky proposed using railway rails as a conductor of electrical energy. At that time, the transmission of electricity through wires was accompanied by large losses (when transmitting direct current, losses in the wire reached 75%). It seemed possible to reduce losses in the line by increasing the cross-section of the conductor. Pirotsky conducted experiments on energy transmission along the rails of the Sestroretsk Railway. Both rails were insulated from the ground, one of them served as a direct wire, the second as a return wire. The inventor tried to use the idea for the development of urban transport and put a small trailer on conductor rails. However, this turned out to be unsafe for pedestrians. However, much later such a system was developed in the modern metro.

The famous electrical engineer Nikola Tesla dreamed of creating a system for wireless energy transmission to anywhere on the planet. In 1899, he took on the construction of a transatlantic communication tower, hoping to realize his electrical ideas under the guise of a commercially profitable enterprise. Under his leadership, a giant 200 kW radio station was built in Colorado. In 1905, a trial launch of the radio station took place. According to eyewitnesses, lightning flashed around the tower and the ionized environment glowed. Journalists claimed that the inventor lit up the sky thousands of miles above the ocean. However, such a communication system soon turned out to be too expensive, and ambitious plans remained unrealized, only giving rise to a whole host of theories and rumors (from “death rays” to the Tunguska meteorite - everything was attributed to the activities of N. Tesla).

Thus, the most optimal solution at that time was overhead power lines. By the early 1890s, it became clear that it was cheaper and more practical to build power plants close to fuel and water resources, rather than, as had been done before, near energy consumers. For example, the first thermal power plant in our country was built in 1879, in the then capital - St. Petersburg, specifically for illuminating the Liteyny Bridge; in 1890, a single-phase current power plant was launched in Pushkino, and Tsarskoe Selo, according to contemporaries, “became the first a city in Europe that was entirely and exclusively illuminated by electricity.” However, these resources were often remote from large cities, which traditionally acted as centers of industry. There was a need to transmit electricity over long distances. The transmission theory was simultaneously developed by the Russian scientist D.A. Lachinov, and the French electrical engineer M. Despres. At the same time, the American George Westinghouse was developing transformers, but the world's first transformer (with an open core) was created by P.N. Yablochkov, who received a patent for it back in 1876.

At the same time, the question arose about the use of alternating or direct current. The creator of the arc light bulb, P.N., was also interested in this issue. Yablochkov, who foreshadowed a great future for high-voltage alternating current. These conclusions were supported by another domestic scientist, M.O. Dolivo-Dobrovolsky.

In 1891, he built the first three-phase power transmission line, which reduced losses to 25%. At that time, the scientist worked for the AEG company, owned by T. Edison. This company was invited to participate in the International Electrotechnical Exhibition in Frankfurt am Main, where the issue of further use of alternating or direct current was decided. An international testing commission was organized under the chairmanship of the German scientist G. Helmholtz. The members of the commission included Russian engineer R.E. Klasson. It was assumed that the commission would test all the proposed systems and answer the question of choosing the type of current and a promising power supply system.

M.O. Dolivo-Dobrovolsky decided to transfer the energy of the waterfall to the river using electricity. Neckar (near the town of Laufen) to the exhibition grounds in Frankfurt. The distance between these two points was 170 km, although up to this point the transmission range usually did not exceed 15 km. The Russian scientist had to build power lines on wooden poles in just one year, create the necessary motors and transformers (“induction coils,” as they were called then), and he brilliantly coped with this task in collaboration with the Swiss company Oerlikon. In August 1891, a thousand incandescent lamps powered by current from the Laufen hydroelectric station were lit for the first time at the exhibition. A month later, Dolivo-Dobrovolsky’s engine powered a decorative waterfall - there was a kind of energy chain, a small artificial waterfall was powered by the energy of a natural waterfall, 170 km away from the first one.

This was how the main energy problem of the late 19th century was resolved - the problem of transmitting electricity over long distances. In 1893, engineer A.N. Shchensnovich is building the world's first industrial power plant on these principles in the Novorossiysk workshops of the Vladikavkaz Railway.

In 1891, on the basis of the Telegraph School in St. Petersburg, the Electrotechnical Institute was created, which began training personnel for the upcoming electrification of the country.

Wires for power lines were initially imported from abroad, however, they began to be produced quite quickly at the Kolchuginsky Brass and Copper Rolling Plant, the United Cable Plants enterprise and the Podobedov plant. But supports have already been produced in Russia - although they were previously used mainly for telegraph and telephone wires. At first, everyday difficulties arose - the illiterate population of the Russian Empire was suspicious of pillars decorated with signs on which a skull was drawn.

Massive construction of power lines begins at the end of the 19th century; this is due to the electrification of industry. The main task that was solved at this stage was the connection of power plants with industrial areas. The voltages were small, usually up to 35 kV, and the task of networking was not put forward. Under these conditions, problems were easily solved with the help of wooden single-post and U-shaped supports. The material was accessible, cheap and fully met the requirements of the time. All these years, the designs of supports and wires have been continuously improved.

For mobile electric transport, the principle of underground electric traction was known, used to power trains in Cleveland and Budapest. However, this method was inconvenient to use, and underground cable power lines were used only in cities for street lighting and power supply to private houses. Until now, the cost of underground power lines exceeds the cost of overhead lines by 2-3 times.

In 1899, the First All-Russian Electrotechnical Congress took place in Russia. Its chairman was the then chairman of the Imperial Russian Technical Society, professor at the Military Engineering Academy and Institute of Technology, Nikolai Pavlovich Petrov. The congress brought together over five hundred people interested in electrical engineering, including people from a wide variety of professions and with a wide variety of education. They were united either by common work in the field of electrical engineering, or by a common interest in the development of electrical engineering in Russia. Until 1917, seven such congresses were held; the new government continued this tradition.

In 1902, electricity was supplied to the Baku oil fields; power lines transmitted electricity with a voltage of 20 kV.

In 1912, construction began on the world's first peat-fired power plant on a peat bog near Moscow. The idea belonged to R.E. Klasson, who took advantage of the fact that coal, which mainly powered power plants of that time, had to be brought to Moscow. This increased the price of electricity, and a peat power plant with a transmission line of 70 km paid for itself quite quickly. It still exists - now it is GRES-3 in Noginsk.

The electric power industry in the Russian Empire in those years was predominantly owned by foreign firms and entrepreneurs, for example, the controlling stake in the largest joint-stock company, the Electric Lighting Society 1886, which built almost all the power plants of pre-revolutionary Russia, belonged to the German company Siemens and Halske, already known to us from history cable manufacturing (see “CABLE-news”, No. 9, pp. 28-36). Another JSC, United Cable Plants, was managed by the AEG concern. Much of the equipment was imported from abroad. Russian energy and its development lagged sharply behind the advanced countries of the world. By 1913, the Russian Empire ranked 8th in the world in terms of the amount of electricity generated.

With the beginning of the First World War, the production of equipment for power lines decreased - the front needed other products that the same factories could produce - telephone field wire, mine cable, enameled wire. Some of these products were introduced into domestic production for the first time, since many imports were stopped due to the war. During the war, the Donetsk Basin Electric Joint Stock Company built a power plant with a capacity of 60,000 kW and imported equipment for it.

By the end of 1916, the fuel and raw materials crisis caused a sharp drop in production at factories, which continued in 1917. After the October Socialist Revolution, all factories and enterprises were nationalized by decree of the Council of People's Commissars (Council of People's Commissars). By order of the VSNKh (Supreme Council of the National Economy) of the RSFSR, in December 1918, all enterprises related to the production of wires and power lines were transferred to the disposal of the Department of Electrical Industry. Almost everywhere, collegial management was created, in which both workers representing the “new government” and representatives of the former management and engineering corps participated. Immediately after coming to power, the Bolsheviks paid great attention to electrification, for example, already during the civil war, despite the devastation, blockade and intervention, 51 power plants with a total capacity of 3,500 kW were built in the country.

The GOELRO plan, drawn up in 1920 under the leadership of a former St. Petersburg lineman for power lines and cable networks, later academician G.M. Krzhizhanovsky, forced the development of all types of electrical engineering. According to it, twenty thermal and ten hydroelectric stations with a total capacity of 1 million 750 thousand kW were to be built. The department of electrical engineering industry in 1921 was transformed into the Main Directorate of Electrical Engineering Industry of the Supreme Economic Council - "Glavelektro". The first head of Glavelektro was V.V. Kuibyshev.

In 1923, the “First All-Russian Agricultural and Handicraft Exhibition” opened in Gorky Park. As a result of the exhibition, the Russkabel plant received a first degree diploma for its contribution to electrification and the production of high-voltage cables.

As the voltage increased and, accordingly, the wire became heavier, a transition was made from wooden to metal supports for power lines. In Russia, the first line on metal supports appeared in 1925 - a double-circuit 110 kV overhead line that connected Moscow and the Shaturskaya State District Power Plant.

In 1926, the country's first central dispatch service was created in the Moscow energy system, which still exists today.

In 1928, the USSR began producing its own power transformers, which were produced by the specialized Moscow Transformer Plant.

In the 1930s, electrification continued at an ever increasing pace. Large power plants are being created (Dneproges, Stalingrad State District Power Plant, etc.), the voltage of transmitted electricity is increasing (for example, the Dneproges-Donbass power line operates with a voltage of 154 kV; and the Nizhne-Svirskaya Hydroelectric Power Station - Leningrad power line with a voltage of 220 kV). At the end of the 1930s, the Moscow-Volzhskaya hydroelectric power station line was built, operating with ultra-high voltage of 500 kV. United energy systems of large regions are emerging. All this required improvement of metal supports. Their designs were continuously improved, the range of standard supports was expanded, and a massive transition was made to supports with bolted connections and lattice supports.

Wooden supports are also used at this time, but their area is usually limited to voltages up to 35 kV. They connect mainly non-industrial rural areas.

During the pre-war five-year plans (1929-1940), large energy systems were created throughout the country - in Ukraine, Belarus, Leningrad, Moscow.

During the war, out of a total installed power plant capacity of ten million kW, five million kW were disabled. During the war years, 61 large power plants were destroyed, and a large amount of equipment was taken by the occupiers to Germany. Some of the equipment was blown up, some was evacuated in record time to the Urals and the East of the country and put into operation there to ensure the functioning of the defense industry. During the war years, a 100 MW turbine unit was launched in Chelyabinsk.

Soviet power engineers, with their heroic work, ensured the operation of power plants and networks during the difficult war years. During the advance of the fascist armies towards Moscow in 1941, the Rybinsk hydroelectric power station was put into operation, providing energy supply to Moscow when there was a shortage of fuel. The Novomoskovsk State District Power Plant, captured by the Nazis, was destroyed. The Kashirskaya State District Power Plant supplied electricity to the industry of Tula, and at one time there was a transmission line that crossed the territory captured by the Nazis. This power line was restored by power engineers in the rear of the German army. The Volkhov hydroelectric power station, which was damaged by German aviation, was also put back into operation. From it, along the bottom of Lake Ladoga (via a specially laid cable), electricity was supplied to Leningrad throughout the blockade.

In 1942, to coordinate the work of three regional energy systems: Sverdlovsk, Perm and Chelyabinsk, the first Joint Dispatch Directorate was created - ODU of the Urals. In 1945, the ODU of the Center was created, which marked the beginning of the further unification of energy systems into a single network throughout the country.

After the war, power grids were not only repaired and restored, but also new ones were built. By 1947, the USSR took second place in the world in electricity production. The United States remained in first place.

In the 50s, new hydroelectric power stations were built - Volzhskaya, Kuibyshevskaya, Kakhovskaya, Yuzhnouralskaya.

Since the late 50s, a stage of rapid growth in electric grid construction began. Every five years, the length of overhead power lines doubled. More than thirty thousand kilometers of new power lines were built every year. At this time, reinforced concrete supports for power lines with “prestressed racks” are being massively introduced and used. They usually housed lines with voltages of 330 and 220 kV.

In June 1954, a nuclear power plant with a capacity of 5 MW began operation in the city of Obninsk. It was the world's first nuclear power plant for pilot industrial purposes.

Abroad, the first industrial nuclear power plant was put into operation only in 1956 in the English city of Calder Hall. A year later, the nuclear power plant in the American Shippingport came into operation.

High voltage direct current power lines are also being constructed. The first experimental power transmission line of this type was created in 1950, in the Kashira-Moscow direction, 100 km long, with a power of 30 MW and a voltage of 200 kV. The Swedes were second on this path. In 1954, they connected the power system of the island of Gotland along the bottom of the Baltic Sea with the power system of Sweden through a 98-kilometer single-pole power line with a voltage of 100 kV and a power of 20 MW.

In 1961, the first units of the world's largest hydroelectric power station were launched.

The unification of metal supports carried out in the late 60s actually determined the basic set of support designs used to this day. Over the past 40 years, just like metal supports, the designs of reinforced concrete supports have remained virtually unchanged. Today, almost all network construction in Russia and the CIS countries is carried out based on the scientific and technological base of the 60-70s.

The world practice of power transmission line construction was not much different from the domestic one until the mid-60s. However, our practices have diverged significantly in recent decades. In the West, reinforced concrete has not become so widespread as a material for supports. There they followed the path of constructing lines on metal multifaceted supports.

In 1977, the Soviet Union produced more electricity than all European countries combined - 16% of world production.

By connecting regional power grids, the Unified Energy System of the USSR is created - the largest electric power system, which was then connected to the power systems of Eastern European countries and formed an international power system, called "World". By 1990, the Unified Energy System of the USSR included 9 of the country's 11 energy associations, covering 2/3 of the territory of the USSR, where more than 90% of the population lived.

It should be noted that in terms of a number of technical indicators (for example, the scale of power plants and voltage levels of high-voltage power transmission lines), the Soviet Union occupied a leading position in the world.

In the 1980s, an attempt was made in the USSR to introduce multifaceted supports produced by the Volzhsky Mechanical Plant into mass construction. However, the lack of necessary technologies determined the design flaws of these supports, which led to failure. This issue was returned to only in 2003.

After the collapse of the Soviet Union, energy workers faced new problems. Very little funds were allocated to maintain the condition of power lines and their restoration; the decline of industry led to the degradation and even destruction of many power lines. A phenomenon has arisen such as the theft of wires and cables for their subsequent delivery to non-ferrous metal collection points as scrap metal. Despite the fact that many of the “earners” die in this criminal trade, and their income is very insignificant, the number of such cases has practically not decreased to this day. This is caused by a sharp decline in the standard of living in the regions, since this crime is mainly committed by marginalized people without work and place of residence.

In addition, ties with the countries of Eastern Europe and the former republics of the USSR, previously connected by a single energy system, were disrupted. In November 1993, due to a large power shortage in Ukraine, a forced transition was made to the separate operation of the UES of Russia and the IPS of Ukraine, which led to the separate operation of the UES of Russia with the rest of the energy systems that are part of the Mir energy system. Subsequently, the parallel operation of the power systems included in the Mir with the central dispatch control in Prague was not resumed.

Over the past 20 years, the physical wear and tear of high-voltage networks has increased significantly and, according to some researchers, has reached more than 40%. In distribution networks the situation is even more difficult. This is complicated by the continuous increase in energy consumption. Obsolescence of equipment also occurs. Most of the facilities correspond in technical level to their Western counterparts of 20 - 30 years ago. Meanwhile, the world energy industry does not stand still; exploration work is being carried out in the field of creating new types of power lines: cryogenic, cryoresistor, semi-open, open-loop, etc.

The domestic electric power industry faces the most important question of solving all these new challenges and tasks.

Literature
1. Shukhardin S. Technology in its historical development.
2. Kaptsov N.A. Yablochkov - the glory and pride of Russian electrical engineering.
3. Laman N.K., Belousova A.N., Krechetnikova Yu.I. The Elektroprovod plant is 200 years old. M., 1985.
4. Russian cable / Ed. M.K. Portnova, N.A. Arskoy, R.M. Lakernik, N.K. Laman, V.G. Radchenko. M., 1995.
5. Valeeva N.M. Time leaves its mark. M., 2009.
6. Gorbunov O.I., Ananyev A.S., Perfiletov A.N., Shapiro R.P-A. 50 years of the Research Design and Technological Cable Institute. Essays on history. St. Petersburg: 1999.
8. Shitov M.A. Northern cable. L., 1979.
7. Sevkabel.120 years / ed. L. Ulitina - St. Petersburg, 1999.
9. Kislitsyn A.L. Transformers. Ulyanovsk: UlSTU, 2001.
10. Turchin I.Ya. Engineering equipment for thermal power plants and installation work. M.: “Higher School”, 1979.
11. Steklov V. Yu. Development of the electric power industry of the USSR. 3rd ed. M., 1970.
12. Zhimerin D.G., History of electrification of the USSR, L., 1962.
13. Lychev P.V., Fedin V.T., Pospelov G.E. Electrical systems and networks, Minsk. 2004
14. History of the cable industry // “CABLE-news”. No. 9. pp. 28-36.

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The degree of development of society is largely determined by the state of telecommunications (telecommunications).

Telecommunications provide the emission, transmission and reception of signs, written text, images and sounds, messages and signals of any kind through wires, radio, optical or other electromagnetic systems. In telecommunications, they operate with an electrical signal, therefore, in order to transmit messages (speech, music, texts, documents, images of moving and stationary objects) over a distance (or for recording on magnetic tape, optical disk), they must be converted into electrical signals, i.e. into electromagnetic vibrations. Without telecommunications it is impossible to imagine not only industry, science, defense, but also human life. Even the most valuable information is useless if there are no communication channels to transmit and receive it. The number of household radio-electronic devices produced in the world alone has long exceeded the number of inhabitants on the planet. And despite the fact that telecommunications, computer technology and radio electronics have developed mainly in the last 50 years, many types of communication systems and household devices have appeared in the last decade, and some literally in recent years.

If transport is a means for moving goods and people, then telecommunications systems and networks are “transport” for “transporting” any information via electromagnetic waves. However, if the first type of transport is in plain sight and therefore the center of attention, the second is mostly hidden and appears to most as some simple means of transmitting telegrams or conducting telephone conversations. After all, no one thinks (except for specialists) how hundreds of thousands of medium and high power transmitters and more than a billion low power transmitters can operate simultaneously, how using a miniature mobile device you can transmit speech, data, images (of medium definition so far) to almost any point on our planet, determine your location and make the necessary computer calculations.

Each of the areas of development of message transmission technology (telegraphy, telephony, data transmission, fax, television, sound broadcasting, etc.) and devices for receiving them (telegraph devices, telephones, faxes, televisions, radios, etc.) has its own history of invention, creation and operation. The names of many inventors are known, but in some cases it is difficult to attribute primacy to anyone alone in the invention of certain technical means of transmitting and receiving messages. Let us note only the most outstanding milestones in the development of these areas of technology.

In 1792, the first semaphore signaling line was built (by French inventors brothers C. and I. Chappe), connecting Paris and Lille (225 km). The signal traveled all the way in 2 minutes. The device for transmitting messages was called a “tachygraph” (literally a cursive writer), and later – a “telegraph”.

The optical telegraph consisted of a chain of towers located on the tops of hills, within a line of sight. Each tower had a vertical pillar with three fixed crossbars: one long horizontal and two short ones movably attached to its ends. With the help of special mechanisms, the crossbars changed their place so that 92 different figures could be formed. Shapp selected the 8,400 most commonly used words and organized them into a code book of 92 pages, each containing 92 words. From tower to tower, first the page number was transmitted, and then the number of the word on it.

Chappe's telegraph was widespread in the 19th century. In 1839–54 The world's longest optical telegraph line operated from St. Petersburg to Warsaw (149 stations, 1,200 km). It transmitted a telegram containing 100 signals and symbols in 35 minutes. Optical telegraphs of various designs were in operation for about 60 years, although they did not provide (due to weather conditions) high reliability and reliability.

Discoveries in the field of electricity contributed to the fact that the telegraph gradually turned from optical to electrical. In 1832, the Russian scientist P. L. Schilling demonstrated the world's first practically usable electromagnetic telegraph in St. Petersburg. The first such communication lines provided transmission of 30 words per minute. A significant contribution to this area was made by the American inventor S. Morse (in 1837 he proposed the code

- Morse code, and in 1840. created a writing machine, which was then used on telegraph lines in all countries for more than a hundred years), Russian scientist B. S. Jacobi (in 1839 he proposed a direct-printing machine, in 1840 - an electrochemical recording method), English physicist D. Hughes (in 1855 developed an original version of an electromechanical direct-printing apparatus), the German electrical engineer and entrepreneur E. Siemens (in 1844 he improved the apparatus of B. S. Jacobi), the French inventor J. Baudot (in 1874 he proposed a method for transmitting several signals over one physical line - temporary compaction; the most widely used in practice were Baudot double telegraphy devices, which operated almost until the middle of the 20th century at a speed of 760 characters per minute; in honor of Baudot’s merits, in 1927, the unit of telegraphy speed - baud - was named after him), Italian physicist G. Caselli (in 1856 he proposed a method of phototelegraphy and implemented it in Russia in 1866 on the St. Petersburg - Moscow line). It is interesting to note that most of the creators of telegraph apparatus were well-rounded individuals. Thus, Pyotr Lvovich Schilling was a military engineer, orientalist and diplomat, later a member of the St. Petersburg Academy of Sciences; Samuel Morse was a professor of painting at New York University in 1837. In 1866, work on laying the first cable across the Atlantic Ocean was completed. Subsequently, all continents were connected by several underwater communication lines, including fiber optic cable.

In 1876, the American inventor A. G. Bell received a patent for the first practically usable telephone apparatus, and in 1878 in New Haven

(USA) the first telephone exchange was introduced. In Russia, the first city telephone exchanges appeared in 1882 in St. Petersburg, Moscow, Odessa and Riga. An automatic telephone exchange (ATS) with a step finder was introduced into

1896 (Augusta, USA.). In the 1940s coordinated automatic telephone exchanges were created, in the 1960s - quasi-electronic automatic telephone exchanges, and in the 1970s the first samples of electronic automatic telephone exchanges appeared. The development of telecommunications proceeded in parallel in many directions: telegraphy, telephony, wired audio broadcasting, radio broadcasting, radio communications, fax communications, television, data transmission, cellular radio communications, personal satellite communications, etc.

During 1906 – 1916 various vacuum vacuum tubes were invented (Lee de Forest - USA, R. Liben - Germany, V.I. Kovalenko - Russia, etc.), which was the impetus for the creation of generators of continuous electrical oscillations (unlike those previously used in spark radio transmitters damped oscillations), amplifiers, modulators and other devices, without which no transmission system can do.

Electrical signal amplifiers have made it possible to increase the range of wired telephone communications through the use of intermediate amplifiers, and the development of high-quality electrical filters has paved the way for the creation of multi-channel frequency division transmission systems.

The development of telephony contributed to the introduction of wired audio broadcasting, in which audio programs are transmitted over separate wires from telephone wires. Single-program wire broadcasting was first started in Moscow in 1925 with the introduction of a 40 W unit that served 50 loudspeakers installed on the streets. Since 1962, 3-program wire broadcasting has been introduced, in which two additional programs are transmitted simultaneously with the first by amplitude modulation of carriers with frequencies of 78 and 120 kHz. In a number of countries, additional audio programs are transmitted over telephone networks.

Theoretical and experimental studies of many scientists, primarily M. Faraday, D. Maxwell and G. Hertz, who created the theory of electromagnetic oscillations, formed the basis for the widespread use of electromagnetic waves, including the creation of wireless ones, i.e. radio transmission systems. An important step in the history of telecommunications was the invention of radio by A. S. Popov in 1895 and the wireless telegraph by G. Marconi in 1896–97. The world's first semantic radiogram, delivered on March 12, 1896 to A.S. Popov, contained only two words “Heinrich Hertz”, as a tribute to the memory of the great scientist who opened the door to the world of radio. Since that time, the use of electromagnetic waves of increasingly higher frequencies to transmit messages began. This was the impetus for the organization of radio broadcasting and the emergence of radio broadcast receivers - the first household radio-electronic devices. The first radio broadcasts began in 1919–20. from the Nizhny Novgorod Radio Laboratory and from experimental broadcasting stations in Moscow, Kazan and other cities. To this

dates back to the beginning of regular radio broadcasts in the USA (1920)

V Pittsburgh and Western Europe (in 1922) in London.

IN In our country, regular radio broadcasting began more than 65 years ago and is now carried out on long, medium and short waves using the amplitude modulation method, as well as in the VHF range (meter waves) using the frequency modulation method. Stereo programs are transmitted in the VHF range. The development of radio broadcasting is moving along the path of introducing digital technologies into all areas of program preparation, transmission, recording and reception. A number of countries have introduced digital radio broadcasting systems using DRM and DAB standards.

In 1935, a radio link with 5 telephone channels was built between New York and Philadelphia (distance 150 km), operating in the range of meter waves, steadily propagating within line of sight. It was a chain of transceiver radio stations (two terminal and two (50 km apart) intermediate - relay) spaced from each other at a distance of direct visibility of their antennas. This is how a new type of radio communication appeared - radio relay communication, which later switched to the decimeter and centimeter wavelength ranges. A distinctive feature of radio relay transmission systems is the ability to simultaneously operate a huge number of such systems in the same frequency range without mutual interference, which is explained by the possibility of using highly directional antennas (with a narrow radiation pattern).

To increase the distance between stations, their antennas are installed on masts or towers 70–100 m high and, if possible, in elevated places. Large amounts of information can be transmitted in these ranges, and the level of atmospheric and industrial interference is low here. Radio relay systems are deployed (built) faster and provide greater savings in non-ferrous metals compared to cable (coaxial) lines. Despite strong competition from fiber-optic and satellite systems, radio relay systems are indispensable in many cases - for transmitting any message (usually television images) from a mobile vehicle to a receiving station with a narrow beam of radio waves. Modern radio relay systems are mostly digital.

IN 1947 the first message about a digital transmission system appeared pulse code modulation (PCM), developed by Bell (USA). Since it was made using tubes (transistors did not yet exist), it was very bulky, consumed a lot of electricity and had low reliability. Only in 1962 was the digital multichannel telecommunications system (MSTC) with time division of channels (PCM-24) put into operation. Today, digital MSTC and corresponding networks are built on the basis of a synchronous digital SDH - SDH hierarchy (with a base speed of 155.52 Mbit/s - STM-1, all other STM-n, which form the basis of SDH equipment, provide information exchange at speeds that are multiples of the base) and on fiber optic cable.

In 1877-80. M. Senlecom (France), A. de Paiva (Portugal) and P. I. Bakhmetev (Russia) proposed the first designs of mechanical systems

television. The creation of television was facilitated by the discoveries of many scientists and researchers: A.G. Stoletov established in 1888-90. basic principles of the photoelectric effect; K. Braun (Germany) invented the cathode ray tube in 1897; Lee de Forest (USA) created a three-electrode lamp in 1906; significant contributions were also made by J. Bird (England), C. F. Jenkins (USA) and L. S. Theremin (USSR), who carried out the first projects of television systems with mechanical development during 1925-26. The beginning of TV broadcasting in the country using the mechanical television system with Nipkow disk (30 lines and 12.5 frames/s) is considered to be 1931. Due to the narrow frequency band occupied by the signal of this system, it was transmitted using radio broadcasting stations in the long and medium wave ranges . The first experiments on an electronic television system were carried out in 1911 by the Russian scientist B. L. Rosing. A significant contribution to the development of electronic television was also made by: A. A. Chernyshev, C. F. Jenkins. A. P. Konstantinov, S. I. Kataev, V. K Zvorykin, P. V. Shmakov, P. V. Timofeev and G. V. Braude, who proposed original designs for various transmitting tubes. This made it possible to create the country's first television centers in 1937 - in Leningrad (with 240 lines) and Moscow (with 343 lines, and since 1941 - with 441 lines). Since 1948, broadcasting began on an electronic television system with a resolution of 625 lines and 50 fields/s, i.e., according to the standard that is now accepted by most countries of the world (in the USA in 1940 a standard of 525 lines and 60 fields/s was adopted). With).

The work of many scientists and inventors on the transmission of color images (A. A. Polumordvinov proposed the first draft of a color TV system in 1899, I. A. Adamian proposed a three-color sequential system in 1926) formed the basis for the creation of various color television systems. Researchers and developers of a color television (DTV) system for broadcasting purposes were faced with a difficult task: to create a system that would be mutually compatible with the existing black-and-white TV system. To do this, the DTV signal must be received by black-and-white TVs in black-and-white form, and the black-and-white TV signal by color TVs must also be received in black-and-white form. It took many years to successfully solve this problem. At the end of 1953, broadcasting on the NTSC DTV system (named after the National Committee of TV Systems that developed it) began in the United States. In this system, a complete color TV signal is generated as the sum of the luminance and chrominance signals. The latter is a color subcarrier modulated by two color difference signals using the quadrature modulation method. The method of transmitting any two messages on one subcarrier (with a 90° phase shift) was proposed in the 40s of the 20th century by the Soviet scientist G. Momot.

However, despite the engineering simplicity of constructing encoding and decoding devices, the NTSC system has not become widespread due to the stringent requirements for the characteristics of equipment and communication channels. It took 14 years to develop other DTV systems (PAL and SECAM), which are less sensitive

to signal distortion in the transmission channel. The PAL system was proposed in Germany, and SECAM in France. The SECAM standard, adopted for broadcasting purposes, was finalized through the joint efforts of Soviet and French scientists. DTV systems NTSC, PAL and SECAM are called composite (from composite - composite, complex signal) in contrast to component systems in which brightness and color difference signals (components) are transmitted separately.

IN Currently, TV broadcasting in the world is carried out on three indicated analogue systems in designated areas of meter and decimeter waves; in this case, the image is transmitted by the method of amplitude modulation of a carrier, and the sound is transmitted by the method of frequency modulation of another carrier (only one standard (L) uses amplitude modulation). Analogue broadcasting is gradually being replaced by digital. Number of digital TV programs according to standard DVB-S, which can be received from satellites, has significantly surpassed the number of analogue ones. Thousands of artificial Earth satellites have been launched into various space orbits, with the help of which they carry out: multi-program direct TV

– and radio broadcasting, radio communications, determining the location (coordinates) of objects, notification of those in distress, personal satellite communications and many other functions.

IN In the United States, in 1998, the transition to high-parity digital television (HDTV) began according to the ATSC standard (18 options are allowed, differing in the number of decomposition lines - from 525 to 1125, scan type and field (frame) frequency). In Europe there is no such categoricalness in the transition to digital HDTV, since it is believed that the potential of the 625-line standard has not yet been fully exhausted. However, equipment according to the HDTV standard (1250 lines) is produced (especially for filming films) and individual broadcasts are carried out.

To deliver TV programs to the population, radio systems are used: terrestrial in the MV and UHF ranges, satellite direct reception, microwave cellular (MMDS, LMDS, MVDS), as well as cable TV systems (coaxial, fiber-optic, hybrid). CATV systems are gaining more and more importance (from accessing the Internet, for ordering TV programs and receiving other services).

An experimental system of black-and-white and color stereo television was created in the 1960s - 70s. team under the leadership of P.V. Shmakov in Leningrad. The introduction of stereo television into broadcasting is hampered mainly by the lack of an effective, relatively cheap and simple display device (screen). What was said at the time by P.V. Shmakov’s proposal to use aircraft to relay TV programs over large areas became widespread in satellite radio communication and TV broadcasting systems. This was the beginning

V 1965 when the USSR launched an artificial earth satellite (AES)"Molniya-1" with transceiver and relay equipment. Today, several thousand satellites with

various purposes. For direct reception of TV programs from satellites, the optimal geostationary orbit is the one in which the satellite rotates as if stationary relative to any point on the Earth within radio visibility. With their help, not only TV programs are rebroadcast (several hundred over European countries), but also sound broadcasting programs, personal radio communications and broadband Internet access, as well as a number of other functions.

An outstanding discovery of the 20th century. is the creation of the transistor in 1948 by W. Shockley, W. Brattain and J. Bardeen, who received the Nobel Prize in 1956. The successes of semiconductor electronics and in particular the emergence of integrated circuits predetermined the rapid development of all technical means of transmitting messages by electrical means and corresponding devices for receiving them and records. In addition to stationary radios and televisions, portable and automobile and even personal “pocket” video equipment appeared.

Works of Soviet scientists N.G. Basova, A.M. Prokhorov and the American scientist Charles Townes, who also received the Nobel Prize, allowed in 1960 to create a laser - a highly efficient source of optical radiation. Fiber-optic transmission systems (FOTS) using semiconductor laser diodes and optical fibers have become a reality since 1970, when ultra-clean glass was produced in the USA. FOSPs ushered in a new era in guide line communication technology. Due to their insensitivity to electromagnetic interference, stealth, low attenuation of transmitted optical signals (less than 0.01 dB/km), and high throughput (more than 40 Gbit/s), they have no competitors among existing physical transmission lines. Exceptions are feeder lines (coaxial cable or waveguide) used to supply modulated high-frequency oscillations to radio transmitting stations. Photonic networks are being built, i.e. fully optical, as well as passive, which do not contain electrical or optical amplifiers.

IN our country has created a fairly developed backbone network for transmitting any type of information via fiber-optic communication lines with access to international lines.

IN In 1956, the first professional video recorder (VM) was created for recording color TV images onto magnetic tape (USA, Ampex, which was headed by a native of Russia), its weight was 1.5 tons. Today, a video camera (TV camera with a built-in video recorder) with advanced functions fits in the palm of your hand. Since 1969, the development of household magnetic video recording began, as well as the production of small-sized studio VMs, and then video cameras. Great demand for VMs has caused competition among manufacturing firms (mainly from Japan).

IN At the beginning, VMs of analogue formats were produced: U-matic, VCR (1970); Betamax, VCR-LR, VHS (1975); Betacam, Video-2000 (1979); S-VHS (1981

g.), Video-8 (1988). But already in 1986, the first format (D-1) of digital video recording on magnetic tape of DTV signals appeared, and then D-2 (1987), D-3

(1990) and D-5 (1993). These VMs were designed to record digital streams without compression at speeds of 225, 127, 125 and 300 Mbit/s, respectively: D-1 and D-5 - component signals, D-2 and D-3 - composite signals. The successful implementation of compression algorithms - eliminating redundancy in TV images (the MPEG family of standards) which reduced the digital stream speed many times over, the use of noise-resistant coding methods and spectrally efficient multi-position modulation methods opened the way for the introduction of digital TV broadcasting: it became possible in a standard TV radio channel (8 MHz wide) for the domestic standard and most others), instead of one analogue one, transmit 5 - 6 digital TV programs with stereophonic sound and additional information. This was taken into account when developing new formats for digital recording on magnetic tape as standard definition component signals

(Betacam SX, Digital Betacam, D-7 (DVSPRO), DVSPRO50, D-9 (Digitals), DVCAM, MPEG IMX, etc.), and high (D5-HD, D-6, CAM-HD, DVSPROHD and etc.). The creators of most formats are Japanese companies, as well as the developers of three standards for recording digital audio signals on magnetic tape R-DAT (1981), S-DAT (1982) and erasable disk - E-DAT (1984).

In 1977, Philips and Sony jointly developed a digital version of the record - a compact disc for playback on a laser player. Around 1985, the production of DVD discs (single-layer, double-layer, single-sided and double-sided, once and repeatedly rewritable) and related equipment began. Portable TV cameras with an optical DVD recorder have appeared. The era of tapeless preparation and production of TV programs with information storage on disk drives, video servers with the widespread use of software-controlled systems has begun.

Modern society cannot be imagined not only without telecommunications, but also without personal computers, local and corporate data networks and the global Internet. There has been an integration of all types of telecommunications and computer technologies. Digital networks and systems are software controlled and synchronized; digital signals are more often processed using microprocessors, signal processes and generated in software (for example, COFDM - a method of modulation and frequency division multiplexing of several thousand orthogonal carriers is implemented in software, since it is difficult to implement in hardware, and it is widely used in many digital radio transmission systems).

It all started with the simplest devices that assisted a person in carrying out certain calculations (accounts, adding machine, calculator). The first electronic computers were created to solve computational problems with a large volume of calculations.

According to the law of the US Department of Defense in the period from 1942 to 1946. At the University of Pennsylvania, the ENIAC (Electronic Numerical) computer was created

Integrator and Automatic Calculator - electronic computing integrator and automatic calculator), which was used in the ballistics laboratory. The equipment was housed in many cabinets, occupied a large room (~ 80 m2), was striking in its size and weight (30 tons, 18 thousand vacuum tubes), and extremely low productivity (10 - 20 thousand operations per second) - it took 3 milliseconds to multiply two numbers. This is hard for a laptop owner to believe. The MESM computer, created in 1946–1947, also belongs to the first generation. in USSR.

The second generation (1960 - 1969) was developed using semiconductor devices (IBM - 701, USA; BESM-4, BESM-6, USSR). Performance increased to 100-500 thousand op/s, but the dimensions were even larger. Third generation of computers (IBM - 360, USA; EC-1030, EC-1060,

USSR) were created in 1970–1979. on chips with a low degree of integration using operating systems and time-sharing mode. The main purpose is automated control systems, scientific and technical problems, computer-aided design systems. Fourth generation computers (1980 – 1989) with speeds of tens and hundreds of mil.op/s were built on large integrated circuits and microprocessors (ILLIAC4, CRAY, USA; Elbrus, PS-2000, USSR, etc.). The scope of their application has also expanded - complex production and social tasks, management, automated workstations, communications.

Simultaneously with the creation of large computers, the class of microcomputers—personal computers (PCs)—was intensively developing. The first microcomputer appeared in 1971 in the USA based on a 4-bit microprocessor, which made it possible to sharply reduce the weight and dimensions of computing devices. As with mainframe computers, first-generation personal computers were hardware and software incompatible. With the advent of the IBM PC in 1981, the situation began to change towards the creation of compatible PCs with significantly greater capacity and calculation accuracy. The huge demand for high-speed PCs with advanced functionality was an incentive to improve microprocessors, the bit capacity of which increased from 4 in 1971 to 32 in 1986, and the clock frequency from 0.5 to 25 MHz. Modern processors have 64 bits with a clock speed of more than 4 GHz.

The development of radio communications has followed the path of mastering increasingly higher frequency ranges in which a significantly larger volume of information can be transmitted. There were many unsolved problems regarding effective compression of transmitted signals, noise-resistant coding and the creation of spectral-efficient digital modulation methods, covering large areas with multi-program broadcasting. The problem of providing two-way radio communication with a subscriber who is on the move or does not have access to the public telephone network was also unresolved. Departmental professional mobile radiotelephone communication systems (for ambulances, road and air traffic control, etc.) were created back in the 70s of the twentieth century (domestic systems “Altai”, “Len”,

"Vilia", etc.). They were portable transceiver radio stations and therefore were not designed for mass use. To do this, it was necessary to make them portable and lightweight, and also, in conditions of limited frequency resources, to find ways to reuse the same frequencies by different subscribers.

The first to appear were one-way radio communication systems - paging systems (personal radio call). They allow you to transmit short text messages to any owner of a portable receiver - a pager. Received alphanumeric characters are displayed on the small screen (indicator) of the receiver. The text of such messages indicating the subscriber's number was first transmitted via a telephone line to the base station, and from there the operator transmitted it to the recipient's pager. At the time this was a great achievement. Later, it became possible not only to receive messages, but also to respond to them with several standard phrases hardwired into the pager’s memory.

This is how cellular mobile radio communication systems were born, the main principle of which was cellular construction and frequency distribution. The service area is divided into a large number of small cells (“cells” - hexagons) with a radius R from 1.5 to 3 km, served by a separate low-power radio base station. A collection of, for example, seven cells forms a cluster with the corresponding numbers of frequencies used. In adjacent clusters, the same frequencies are used, but assigned to the cells so that the distance between the centers of cells (different clusters) with the same frequencies is 4.5R - sufficient to eliminate mutual influence.

The first control systems were analog, then digital systems were used everywhere. Their functionality gradually expanded - from two-way transmission of speech only to the transmission of data, still and moving images (still of average quality). The service area also increased - from a small area of ​​the city to the state as a whole, and in the presence of international agreements - also on the territory of other countries. By the end of 1996 (10 years ago), the number of SPR subscribers in the world was just over 15 million. Today in our country alone there are more than 4 million subscribers, in the world there are more than 2 billion.

It is necessary to note another achievement of the end of the twentieth century - the creation of a family of xDSL standards (Digital Subscriber Line), designed to significantly increase the throughput of twisted copper pairs used at the subscriber end to the telephone exchange (therefore called the “last mile”). The use of new types of multi-position modulation allows large amounts of information to be transmitted over a narrowband copper pair: in the ADSL version - from the subscriber to the telephone exchange - at a speed of 16 - 640 kbit/s, to the subscriber - 6 Mbit/s over a distance of 2.7 km, and in the VDSL – provides transmission at a speed of 52 Mbit/s (PBX – subscriber) over a distance of up to 300 m. Not so long ago it was believed that it was impossible to transmit a TV signal over such a channel at all. Thus, with

Using VDSL technology, it is possible to transmit up to 10 digital TV programs (5 Mbit/s per program) of broadcast quality, which is a colossal achievement.

The company's central office is located in the capital of Kazakhstan - Astana. The company employs about 30 thousand people. JSC Kazakhtelecom has regional divisions in each region of the country and provides communication services throughout the country.

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Chapter 1. General characteristics of the enterprise. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
1.Historical information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.Organizational structure of the enterprise. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.Organization of the production process. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4. Main economic and financial indicators. . . . . . . . . . . . . . . . . . . . . . 8
Chapter 2. Marketing research of OJSC Rostelecom. . . . . . . . . . . .. . . . . . . 12
Chapter 3. Conclusions and proposals for the entire main part of the report. . . . . . . . . . . . . . .17
Conclusion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
Bibliography. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

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1. History of the development of communication lines

Communication lines arose simultaneously with the advent of the electric telegraph. The first communication lines were cable. However, due to imperfect cable design, underground cable communication lines soon gave way to overhead ones. The first long-distance air line was built in 1854 between St. Petersburg and Warsaw. In the early 70s of the last century, an overhead telegraph line was built from St. Petersburg to Vladivostok with a length of about 10 thousand km. In 1939, the world's longest high-frequency telephone line, Moscow-Khabarovsk, 8,300 km long, was put into operation.

The creation of the first cable lines is associated with the name of the Russian scientist P.L. Shilling. Back in 1812, Schilling demonstrated the explosions of sea mines in St. Petersburg, using an insulated conductor he created for this purpose.

In 1851, simultaneously with the construction of the railway, a telegraph cable insulated with gutta-percha was laid between Moscow and St. Petersburg. The first submarine cables were laid in 1852 across the Northern Dvina and in 1879 across the Caspian Sea between Baku and Krasnovodsk. In 1866, the transatlantic cable telegraph line between France and the USA came into operation.

In 1882-1884. The first city telephone networks in Russia were built in Moscow, Petrograd, Riga, and Odessa. In the 90s of the last century, the first cables with up to 54 cores were suspended on the city telephone networks of Moscow and Petrograd. In 1901, construction of an underground city telephone network began.

The first designs of communication cables, dating back to the early 20th century, allowed telephone transmission over short distances. These were the so-called city telephone cables with air-paper insulation of the cores and twisting them in pairs. In 1900-1902 was

a successful attempt was made to increase the transmission range by artificially increasing the inductance of cables by including inductors in the circuit (Pupin's proposal), as well as using conductive cores with a ferromagnetic winding (Krupa's proposal). Such methods at that stage made it possible to increase the range of telegraph and telephone communications several times.

An important stage in the development of communication technology was the invention, and starting from 1912-1913. mastering the production of electronic tubes. In 1917 V.I. Kovalenkov developed and tested on the line a telephone amplifier using vacuum tubes. In 1923, telephone communication with amplifiers was established on the Kharkov-Moscow-Petrograd line.

In the 1930s, the development of multi-channel transmission systems began. Subsequently, the desire to expand the range of transmitted frequencies and increase the capacity of lines led to the creation of new types of cables, the so-called coaxial. But their mass production dates back only to 1935, when new high-quality dielectrics such as escapon, high-frequency ceramics, polystyrene, styroflex, etc. appeared. These cables allow the transmission of energy at current frequencies of up to several million hertz and allow them to transmit television programs over long distances. The first coaxial line for 240 HF telephony channels was laid in 1936. The first transatlantic submarine cables, laid in 1856, provided only telegraph communication, and only 100 years later, in 1956, an underwater coaxial line was built between Europe and America for multi-channel telephone communications.

In 1965-1967 experimental waveguide communication lines for transmitting broadband information appeared, as well as cryogenic superconducting cable lines with very low attenuation. Since 1970, work has actively begun on the creation of light guides and optical cables using visible and infrared radiation in the optical wavelength range.

The creation of a fiber light guide and the achievement of continuous generation of a semiconductor laser played a decisive role in the rapid development of fiber-optic communications. By the beginning of the 80s, fiber-optic communication systems were developed and tested in real conditions. The main areas of application of such systems are telephone networks, cable television, intra-site communications, computer technology, process control and management systems, etc.

In Russia and other countries, city and long-distance fiber-optic communication lines have been laid. They are given a leading place in the scientific and technological progress of the communications industry.

2. Design and characteristics of optical communication cables

Types of optical communication cables

An optical cable consists of quartz glass optical fibers (light guides) twisted in a specific system and enclosed in a common protective sheath. If necessary, the cable may contain power (strengthening) and damping elements.

Existing OKs, according to their purpose, can be classified into three groups: mainline, zonal and urban. Underwater, facility and installation OKs are divided into separate groups.

Trunk communications are intended for transmitting information over long distances and a significant number of channels. They must have low attenuation and dispersion and high information throughput. Single-mode fiber with core and cladding dimensions of 8/125 microns is used. Wavelength 1.3...1.55 µm.

Zone OKs are used to organize multi-channel communications between the regional center and districts with a communication range of up to 250 km. Gradient fibers with dimensions of 50/125 microns are used. Wavelength 1.3 µm.

City OKs are used as connections between city automatic telephone exchanges and communication centers. They are designed for short distances (up to |10 km) and a large number of channels. Gradient fibers (50/125 µm). Wavelength 0.85 and 1.3 µm. These lines, as a rule, operate without intermediate linear regenerators.

Underwater sensors are intended for communication across large water barriers. They must have high mechanical tensile strength and have reliable moisture-resistant coatings. For underwater communications it is also important to have low attenuation and long regeneration lengths.

Object OKs are used to transfer information within an object. This includes institutional and videotelephone communications, an internal cable television network, as well as on-board information systems of mobile objects (aircraft, ship, etc.).

Mounting OKs are used for intra- and inter-unit installation of equipment. They are made in the form of bundles or flat tapes.

Optical fibers and features of their manufacture

The main element of the optical fiber is an optical fiber (light guide), made in the form of a thin cylindrical glass fiber, through which light signals with wavelengths of 0.85...1.6 microns are transmitted, which corresponds to the frequency range (2.3...1 ,2) 1014 Hz.

The light guide has a two-layer design and consists of a core and a cladding with different refractive indices. The core serves to transmit electromagnetic energy. The purpose of the shell is to create better reflection conditions at the core-cladding interface and protection from interference from the surrounding space.

The core of the fiber usually consists of quartz, and the cladding can be quartz or polymer. The first fiber is called quartz-quartz, and the second is quartz-polymer (organosilicon compound). Based on the physical and optical characteristics, preference is given to the first. Quartz glass has the following properties: refractive index 1.46, thermal conductivity coefficient 1.4 W/μ, density 2203 kg/m3.

A protective coating is placed on the outside of the light guide to protect it from mechanical stress and coloring. The protective coating is usually made in two layers: first, silicone-organic compound (SIEL), and then epoxy acrylate, fluoroplastic, nylon, polyethylene or varnish. Total fiber diameter 500...800 µm

In existing OK designs, three types of fibers are used: stepped with a core diameter of 50 μm, gradient with a complex (parabolic) core refractive index profile, and single-mode with a thin core (6...8 μm)

In terms of frequency throughput and transmission range, single-mode fibers are the best, and stepped fibers are the worst.

The most important problem in optical communications is the creation of optical fibers (OFs) with low losses. Quartz glass is used as a starting material for the manufacture of optical fibers, which is a good medium for the propagation of light energy. However, as a rule, glass contains a large amount of foreign impurities, such as metals (iron, cobalt, nickel, copper) and hydroxyl groups (OH). These impurities lead to a significant increase in losses due to absorption and scattering of light. To obtain optical fiber with low losses and attenuation, it is necessary to get rid of impurities so that there is chemically pure glass.

Currently, the most common method for creating low-loss optical fibers is chemical vapor deposition.

Obtaining OM by chemical vapor deposition is carried out in two stages: a two-layer quartz workpiece is prepared and fiber is drawn from it. The workpiece is made as follows

A stream of chlorinated quartz and oxygen is supplied inside a hollow quartz tube with a refractive index 0.5...2 m long and 16...18 mm in diameter. As a result of a chemical reaction at high temperatures (1500...1700° C), pure quartz is deposited in layers on the inner surface of the tube. Thus, the entire internal cavity of the tube is filled, except for the center itself. To eliminate this air channel, an even higher temperature is applied (1900 ° C), due to which collapse occurs and the tubular billet turns into a solid cylindrical billet. The pure precipitated quartz then becomes the refractive index OB core, and the tube itself acts as the refractive index cladding. The fiber is drawn from the workpiece and wound onto a receiving drum at the glass softening temperature (1800...2200° C). From a piece 1 m long, over 1 km of optical fiber is obtained.

The advantage of this method is not only the production of optical fibers with a core made of chemically pure quartz, but also the possibility of creating gradient fibers with a given refractive index profile. This is done: through the use of alloyed quartz with the addition of titanium, germanium, boron, phosphorus or other reagents. Depending on the additive used, the refractive index of the fiber may change. Thus, germanium increases and boron decreases the refractive index. By selecting the doped quartz formulation and maintaining a certain volume of additive in the layers deposited on the inner surface of the tube, it is possible to ensure the required nature of the change across the cross-section of the fiber core.

Optical cable designs

OK designs are mainly determined by their purpose and scope of application. In this regard, there are many design options. Currently, a large number of cable types are being developed and manufactured in various countries.

However, the entire variety of existing cable types can be divided into three groups

concentrically twisted cables

shaped core cables

flat ribbon cables.

Cables of the first group have a traditional concentrically twisted core, similar to electrical cables. Each subsequent twist of the core has six more fibers compared to the previous one. Such cables are known mainly with a number of fibers of 7, 12, 19. Most often, the fibers are located in separate plastic tubes, forming modules.

The cables of the second group have a shaped plastic core in the center with grooves in which the optical fibers are placed. The grooves and, accordingly, the fibers are located along the helicoid, and therefore they do not experience longitudinal impact on the rupture. Such cables can contain 4, 6, 8 and 10 fibers. If it is necessary to have a high-capacity cable, then several primary modules are used.

A ribbon cable consists of a stack of flat plastic strips into which a certain number of OBs are embedded. Most often, there are 12 fibers in a tape, and the number of tapes is 6, 8 and 12. With 12 tapes, such a cable can contain 144 fibers.

In addition to optical fibers, optical cables usually contain the following elements:

power (strengthening) rods that take on longitudinal load and tensile strength;

fillers in the form of solid plastic threads;

reinforcing elements that increase the resistance of the cable under mechanical stress;

outer protective sheaths that protect the cable from penetration of moisture, vapors of harmful substances and external mechanical influences.

Various types and designs of OK are manufactured in Russia. To organize multi-channel communication, four- and eight-fiber cables are mainly used.

French-made OKs are of interest. They are, as a rule, completed from unified modules consisting of a plastic rod with a diameter of 4 mm with ribs around the perimeter and ten OBs located along the periphery of this rod. Cables contain 1, 4, 7 such modules. On the outside, the cables have an aluminum and then polyethylene sheath.

450 g. BC e.– Ancient Greek philosophers Democritus and Kleoxenus proposed the creation of an optical torch telegraph.

1600 g. – a book by the English scientist Gilbert “On the magnet, magnetic bodies and the great magnet - the Earth”. It described the already known properties of a magnet, as well as the author’s own discoveries.

1663 g. – The German scientist Otto von Guericke conducted experimental work to determine the phenomenon of electrostatic repulsion of unipolarly charged objects.

1729 g. -Englishman Gray discovered the phenomenon of electrical conductivity.

1745 g. – German physicist Ewald Jürgen von Kleist and Dutch physicist Pieter van Muschenbrouck created the “Leyden jar” - the first capacitor.

1753 g. — Leipzig physicist Winkler discovered a way to transmit electric current through wires.

1761. – one of the greatest mathematicians, St. Petersburg academician Leonhard Euler, first expressed the idea of ​​​​transmitting information using ether vibrations.

1780 g. – Galvani discovered the first detector design that was not artificial, but natural – biological.

1785 g. -French physicist Charles Coulomb, the founder of electrostatics, established that the force of interaction between electric charges is proportional to their magnitudes and inversely proportional to the square of the distance between them.

1793. – K. Stapp invented the “optical telegraph”.

1794 g. – the first “optical telegraph” line was put into operation, built between Lille and Paris (about 250 km), which had 22 intermediate (relay) stations.

1800 g. – Volta invented a galvanic cell – the so-called “Volta Column”, which became the first source of direct current.

1820. – Oerstedt discovered the connection between electric current and magnetic field. Electric current generates a magnetic field.

1820. –A. M. Ampere discovered the interaction of electric currents and established the law of this interaction (Ampere's law).

1832. – Pavel Lvovich Schilling invented a pointer telegraph apparatus, in which five hands served as indicators.

1837. - American scientist C. Page created the so-called “grumbling wire”.

1838– The German scientist K. A. Steingel invented the so-called grounding.

1838. – S. Morse invented the original uneven code.

1839. – the longest “optical telegraph” line in the world at that time was built between St. Petersburg and Warsaw (1200 km).

1841. -under the leadership of Jacobi, the first telegraph line was built between the Winter Palace and the General Headquarters.

1844. - under the leadership of Morse, a telegraph line was built between Washington and Baltimore with a total length of 65 km.

1850 g. – B.S. Jacobi developed the world's first telegraph apparatus (three years earlier than Morse) with letter printing of received messages, in which, as he said, “the registration of characters was carried out using a typographic font.”

1851. – Morse code has been slightly modified and recognized as an international code.

1855.– The first telegraph printing machine was invented by the French telegraph mechanic E. Baudot.

1858. – Winston invented a device that outputs information directly onto a telegraph tape built into it (the prototype of a modern telegraph machine).

1860. - Philipp Reis, a physics teacher at a school in Friedrichsdorf (Germany), used improvised means (a barrel stopper, a knitting needle, an old broken violin, a coil of insulated wire and a galvanic element) to create an apparatus to demonstrate the principle of the ear.

1868. – Mahlon Loomis demonstrated to a group of American congressmen and scientists the operation of a prototype wireless communication line with a length of 22 km.

1869. - Professor of Kharkov University Yu. I. Morozov developed a transmitter - a prototype of a microphone.

July 30, 1872– M. Loomis was issued the world's first patent (No. 129971) for a wireless telegraph system.

1872. - Russian engineer A. N. Lodygin invented the first electric incandescent lighting lamp, which ushered in the era of electric vacuum technology.

1873. - English physicist W. Crookes invented a device - a “radiometer”.

1873. –Maxwell combined all his works in “The Doctrine of Electricity and Magnetism.”

1874. – Baudot created a multiple printing telegraphy system.

1877 g. - D. E. Hughes designed a telephone transmitter, which he called a microphone.

1877. – in the USA, the first telephone exchange was built according to the design of the Hungarian engineer T. Puskás.

1878. -Stuart came to the conclusion that in the Earth’s atmosphere there is an ionized region of the ionosphere - a conducting layer of the atmosphere, i.e. The Earth and the ionosphere are the plates of a capacitor.

1879. – Russian scientist Michalsky was the first in the world to use carbon powder in a microphone. This principle is used to this day.

1882.– P. M. Golubitsky invented a highly sensitive telephone and designed a desk telephone with a lever to automatically switch the circuit by changing the position of the handset.

1883. – Edison discovered the effect of atomizing the substance of an incandescent filament in an electric lamp.

1883. – P. M. Golubitsky created a telephone with two poles located eccentrically relative to the center of the membrane, which still works today.

1883. -P. M. Golubitsky designed a microphone with coal powder.

1886. – G. Hertz invented a method for detecting electromagnetic waves.

1887. - Russian inventor K. A. Mosnitsky created a “self-acting central switch” - the predecessor of automatic telephone exchanges (PBX).

1887. – the famous experiments of Heinrich Hertz were carried out, proving the reality of radio waves, the existence of which followed from the theory of J. C. Maxwell.

1889. - American inventor A. G. Stringer received a patent for an automatic telephone exchange.

1890. – the famous French physicist E. Branly invented a device capable of responding to electromagnetic radiation in the radio range. A coherer served as a detector in the receiver.

1893. - Russian inventors M.F. Freidenberg and S.M. Berdichevsky - Apostolov proposed their “telephone connector” - a telephone exchange with step finders.

1895. – Freidenberg M.F. patented one of the most important components of decade-step automatic telephone exchanges - a pre-finder (a device for automatically searching for the called subscriber).

1896. – Freidenberg M.F. created a machine finder with reverse control from a register installed in the subscriber’s device.

April 25 (May 7), 1895. - the first public demonstration of a radio line by A. S. Popov. This day in our country is celebrated annually as Radio Day.

March 24 (12), 1896– with the help of A.S. Popov’s equipment, the world’s first text radiogram was transmitted, which was recorded on a telegraph tape.

1896. – Freudenberg patented a machine-type finder.

1896. - Berdichevsky - Apostolov created an original PBX system for 11 thousand numbers.

1898. – The longest air telephone line in the world (660 km) was built between Moscow and St. Petersburg.

May 1899. – For the first time in audio form, on-air telegrams were listened to on a headphone in Russia by A. S. Popov’s assistants P. N. Rybkin and A. S. Troitsky.

1899. – A. S. Popov was the first to use radio communication to save a ship and people. The communication range exceeded 40 km.

1900 g. – the beginning of radio armament of ships of the Russian Navy, i.e., the practical and regular use of radio communications in military affairs.

August 24, 1900– Russian scientist Konstantin Dmitrievich Persky introduced the concept of television “television”.

1904. -Englishman Fleming created a tube diode.

1906. -American Lee de Forest invented a lamp with a control electrode - a three-electrode lamp that provides the ability to amplify alternating currents.

July 25, 1907. – B. L. Rosing received the “Privilege for No. 18076” for the receiving tube for “electric telescopy”. Tubes designed for receiving images were later called picture tubes.

1912. – V.I. Kovalenkov developed a generator lamp with an external anode cooled by water.

1913. – Meissner discovered the possibility of self-excitation of oscillations in a circuit containing an electron tube and an oscillating circuit.

1915. – Russian engineer B.I. Kovalenkov developed and applied the first duplex telephone broadcast using triodes.

1918. – E. Armstrong invented the superheterodyne receiver.

1919. – Schottky invented the tetrode, which found practical application only in 1924–1929.

1922. – O. V. Losev discovered the effect of amplification and generation of high-frequency oscillations using crystals.

1922. – radio amateurs have discovered the property of short waves to propagate over any distance due to refraction in the upper layers of the atmosphere and reflection from them.

1923. -Soviet scientist Losev O.V. was the first to observe the glow of a semiconductor (silicon carbide) diode when an electric current was passed through it.

March 1929– the first regular broadcasts began in Germany.

1930s– meter waves were mastered, propagating in a straight line, without bending around the earth’s surface (i.e. within line of sight).

1930. – based on the work of Langmuir, pentodes appeared.

April 29 and May 2, 1931– the first transmissions of television images by radio were made in the USSR. They were carried out by decomposing the image into 30 lines.

August 1931– German scientist Manfred von Ardenne was the first in the world to publicly demonstrate a fully electronic television system based on a traveling beam sensor with a 90-line scan.

September 24, 1931-Soviet scientist S. I. Kataev received priority for the invention of a transmitting tube with charge filling, a mosaic target and switching using secondary electrons.

1934. – E. Armstrong invented frequency modulation (FM).

1936. – Soviet scientists P.V. Timofeev and P.V. Shmakov were issued an author’s certificate for a cathode ray tube with image transfer.

1938. – in the USSR, the first experimental television centers were put into operation in Moscow and Leningrad. The decomposition of the transmitted image in Moscow was 343 lines, and in Leningrad - 240 lines at 25 frames per second. On July 25, 1940, the 441-line decomposition standard was approved.

1938. – In the USSR, serial production of console receivers for 343 lines of the TK-1 type with a screen size of 14x18 cm began.

1939. – E. Armstrong built the first radio station operating in the VHF radio wave range.

1940s– mastered decimeter and centimeter waves.

1948. - American researchers under the leadership of Shockley invented a semiconductor triode-transistor.

1949. – in the USSR, serial production of KVN-49 televisions on a tube with a diameter of 17 cm began (developed by V.K. Kenigson, N.M. Varshavsky, N.A. Nikolaevsky).

March 4, 1950– The first scientific center for receiving television networks was created in Moscow.

1953 –1954– The first domestic radio relay communication equipment for the meter range, “Crab,” was developed in the USSR. It was used on the communication line between Krasnovodsk and Baku across the Caspian Sea.

Mid 50s–The Strela family of radio relay equipment was developed in the USSR.

October 4, 1957– The first Soviet artificial Earth satellite (AES) was launched into orbit, and the era of space communications began.

1958. – Based on the R-600 operating in the 4 GHz range, the first main radio relay line Leningrad–Tallinn was put into operation.

1960. – The first transmission of color television took place in Leningrad from the experimental station of the Leningrad Electrotechnical Institute of Communications.

1965. – the Kozitsky plant developed and produced the first tube-semiconductor TV “Evening”.

November 29, 1965–The first transmission of color television programs via the SECAM system from Moscow to Paris via the Molniya-1 communications satellite was carried out.

1966. – The Kuntsevo Mechanical Plant in Moscow developed and produced a small-sized portable TV “Yunost”, assembled entirely on transistors.

May 28, 1966–The first transmission of color television programs via the SECAM system was carried out from Paris to Moscow via the Molniya-1 communications satellite.

November 2, 1967– A network of stations for receiving television programs from artificial Earth satellites “Molniya – 1”, called “Orbit”, was put into operation.

November 4, 1967- The All-Union Radio and Television Transmitting Station of the USSR Ministry of Communications came into operation.

1970. – Ultra-pure quartz fiber made it possible to transmit a light beam over a distance of up to 2 km.

September 5, 1982–The first satellite teleconference “Moscow – Los Angeles” dedicated to the dialogue between musical groups of the USSR and the USA.

April 1988–In the USSR, the use of a set of wearable television journalistic equipment with a video recorder began.

February 1999– the beginning of multi-channel digital satellite TV broadcasting (“NTV-plus”). Transmission of up to 69 television channels.

2004. – The Government of the Russian Federation is making a decision to introduce digital TV broadcasting via the European DVB system.