Development of modern means of communication
Communication means - technical and software used for generating, receiving, processing, storing, transmitting, delivering telecommunication messages or postal items, as well as other hardware and software used in the provision of communication services or ensuring the functioning of communication networks.
types of communication Wired (telephone, telegraph, etc.) Wireless, which, in turn, distinguish: radio (omnidirectional, narrowly directed, cellular and other radio systems), radio relay and space (satellite) devices, systems and complexes.
Means of communication. The first is the emergence of oral speech. Scientists have identified five powerful shocks that accelerated the development of mankind, which culture received during its existence:
The second is the invention of writing, which allowed a person to communicate with other people who are not in direct contact with him.
The third is the emergence and spread of printing.
Fourth, the emergence electronic means mass communication, which provided an opportunity for everyone to become a direct witness and participant in the historical and cultural process taking place all over the world. Radio Television
The fifth, according to many experts, is the emergence and development of the Internet as a new means of communication that has provided ample opportunities in the forms and methods of obtaining and transmitting information, as well as the implementation of many other functions.
Stages in the development of communications Creation of an optical telegraph - a device for transmitting information over long distances using light signals. The Frenchman Claude Chappe invented this system.
Communication by wire. The first electric telegraph was created in 1837 by English inventors: William Cook Charles Watson
Late model of the Cooke and Whetstone telegraph. The signals actuated the arrows on the receiver, which pointed to different letters and thus conveyed the message.
Morse code In 1843, the American artist Samuel Morse invented a new telegraph code that replaced the Cook and Whetstone code. He developed signs for each letter of dots and dashes.
And Charles Whetstone created a system in which the operator, using Morse code, typed messages on a long paper tape that entered the telegraph machine. At the other end of the wire, the recorder typed the received message onto another paper tape. Subsequently, the recorder was replaced by a signaling device that converted dots and dashes into long and short sounds. The operators listened to the messages and recorded their translation.
Invention of the first telephone. Alexander Graham Bell (1847-1922), together with Thomas Watson (1854 - 1934), designed a device consisting of a transmitter (microphone) and a receiver (speaker). The microphone and speaker were arranged in the same way. In the microphone, the speaker's voice caused the membrane to vibrate, causing electric current to oscillate . In dynamics, current was applied to the membrane, causing it to oscillate and reproduce the sounds of a human voice. The first telephone conversation took place on March 10, 1876.
The invention of radio. The creator of the radio Alexander Stepanovich Popov (1859-1906). On May 7, 1895, Popov demonstrated the radio receiver he invented at a meeting of the physics department of the Russian Physical and Chemical Society. A type of wireless communication in which radio waves that freely propagate in space are used as a signal carrier.
Satellite connection. Satellites are unmanned space vehicles that fly in orbit around the Earth. They can transmit telephone conversations and TV signals to anywhere in the world. They also transmit weather and navigation information. In 1957, the USSR launched Sputnik 1, the world's first artificial Earth satellite.
In 1960, the Courier and Echo satellites were launched in the USA. They broadcast the first telephone conversations between the US and Europe. In 1962, Telstar, the first television satellite, went into orbit in the United States.
Fiber-optic communication lines. Fiber-optic communication lines (FOCL) are currently considered the most advanced physical medium for information transmission. Data transmission in optical fiber is based on the effect of total internal reflection. Thus, the optical signal transmitted by the laser on one side is received on the other, much more distant side. To date, a huge number of trunk fiber-optic rings, intracity and even intra-office, have been built and are being built.
Laser communication system A rather interesting solution for high-quality and fast network communication was developed by the German company Laser2000. The two presented models look like the most ordinary video cameras and are designed for communication between offices, inside offices and along corridors. Simply put, instead of laying an optical cable, you just need to install inventions from Laser2000. However, in fact, these are not video cameras, but two transmitters that communicate with each other by means of laser radiation. Recall that a laser, unlike ordinary light, such as lamp light, is characterized by monochromaticity and coherence, that is, laser beams always have the same wavelength and scatter little.
Links to sources of information and images: www.digimedia.ru/articles/svyaz/setevye-tehnologii/istoriya/faks-istoriya-ofisnogo-vorchuna/ http://ru.wikipedia.org/wiki/%D0%9F%D0% BE%D0%BF%D0%BE%D0%B2,_%D0%90%D0%BB%D0%B5%D0%BA%D1%81%D0%B0%D0%BD%D0%B4%D1% 80_%D0%A1%D1%82%D0%B5%D0%BF%D0%B0%D0%BD%D0%BE%D0%B2%D0%B8%D1%87 http://geniusweb.ru/? feed=rss2 en.wikipedia.org/wiki/ Radio http://www.5ka.ru/88/19722/1.html
In the modern world, there are various means of communication that are constantly evolving and improving. Even such a traditional type of communication as a postal message (delivery of messages in writing) has undergone significant changes. This information is delivered by railroads and airplanes instead of the old mail coaches.
With the development of science and technology, new types of communication appear. So in the 19th century, a wire telegraph appeared, through which information was transmitted using Morse code, and then the telegraph was invented, in which dots and dashes were replaced by letters. But this type of communication required long transmission lines, laying cables under the ground and water, in which information was transmitted by means of electrical signals. The need for transmission lines remained in the transmission of information by telephone.
At the end of the 19th century, radio communication appeared - the wireless transmission of electrical signals over long distances using radio waves (electromagnetic waves with a frequency in the Hz range). But for the development of this type of communication, it was necessary to increase its range, and for this it was necessary to increase the power of transmitters and the sensitivity of receivers receiving a weak radio signal. These problems were gradually solved with the advent of new inventions - vacuum tubes in 1913, and after the Second World War they began to be replaced by semiconductors. integrated circuits. Powerful transmitters and sensitive receivers appeared, their sizes decreased, and their parameters improved. But the problem remained - how to make radio waves go around the globe.
And the property of electromagnetic waves was used to be partially reflected at the interface between two media (waves were reflected weakly from the surface of the dielectric, and almost without loss from the conducting surface). As such a reflective surface, the layer of the earth's ionosphere, the upper layer of the atmosphere consisting of ionized gases, began to be used).
Back in 1902, English mathematician Oliver Heaviside and American electrical engineer Arthur Edwin Kennelly almost simultaneously predicted that an ionized layer of air exists above the Earth - a natural mirror that reflects electromagnetic waves. This layer was called the ionosphere. The Earth's ionosphere was supposed to make it possible to increase the range of propagation of radio waves to distances exceeding the line of sight. Experimentally, this assumption was proven in Radio frequency pulses were transmitted vertically upwards and returned signals were received. Measurements of the time between sending and receiving pulses made it possible to determine the height and number of reflection layers.
Reflected from the ionosphere, short waves return to the Earth, leaving hundreds of kilometers of the "dead zone" under them. Having traveled to the ionosphere and back, the wave does not “calm down”, but is reflected from the surface of the Earth and again rushes to the ionosphere, where it is reflected again, etc. Thus, repeatedly reflected, the radio wave can go around the globe several times. It was found that the reflection height depends primarily on the wavelength. The shorter the wave, the higher its reflection occurs and, consequently, the larger the “dead zone”. This dependence is true only for the short-wavelength part of the spectrum (up to approximately 25–30 MHz). For shorter wavelengths, the ionosphere is transparent. Waves penetrate it through and through and go into outer space. It can be seen from the figure that the reflection depends not only on the frequency, but also on the time of day. This is due to the fact that the ionosphere is ionized by solar radiation and gradually loses its reflectivity with the onset of darkness. The degree of ionization also depends on solar activity, which varies throughout the year and from year to year in a seven-year cycle.
This layer perfectly reflects radio waves from a length of meters. Repeatedly and alternately reflected from the ion of the sphere and the surface of the earth, short radio waves go around the globe, transmitting information to the most remote parts of the planet. After being telephone invented and found ways to implement long-range radio communications, naturally there was a desire to combine these two achievements. It was necessary to solve the problem of transmitting low-frequency electrical vibrations created by the vibration of the telephone receiver membrane under the influence of the human voice. And it was solved by mixing these low frequency vibrations with the high frequency electrical vibrations of the radio transmitter. The form of high-frequency radio waves changed in strict accordance with what sounds gave rise to low-frequency electrical vibrations. Sound vibrations began to propagate at the speed of radio waves. In the radio receiver, the mixed radio signal was separated and low-frequency sound vibrations reproduced the transmitted sounds.
Significant achievements in the development of means of communication were the inventions of the phototelegraph and television communications. Video signals are transmitted with the help of these means of communication. Now, with the help of phototelegraphy, the text of newspapers and various information are transmitted over great distances. The number of television channels that occupy the region of ultra-high radio frequencies from 50 to 900 MHz is constantly growing. Every TV channel has a width of about 6 MHz. Within the operating frequency of the channel, 3 signals are transmitted: audio, transmitted according to the method frequency modulation; video signal transmitted by the method of amplitude modulation; synchronization signal.
Naturally, for the implementation of television communications, two transmitters are already needed: one for sound, the other for video signals. The next step in the improvement of television communications was the invention of color television. But modern requirements for communication facilities all the time require their further improvement, now the introduction of digital information, image, sound transmission systems is beginning, which in the future will replace the current analog television. Television receivers of the new generation allow you to receive digital and analog transmissions. Familiar TV screens and displays are being replaced by liquid crystal displays. Liquid crystal silicone displays using thin-film technology can dramatically reduce energy consumption due to the fact that the backlight of the screen is not needed. Sharp has already created televisions with new features that have access to the Internet and allow you to use e-mail. The use of digital systems, liquid crystals, and optical fibers in communication means made it possible at the turn of the century to solve several extremely important problems for humans at once: reducing energy consumption, reducing (or, conversely, increasing) the size of equipment, multifunctionality, and accelerating information exchange.
With the help of such communication satellites, a variety of information is transmitted: from radio and television broadcasts to top-secret military information. A communications satellite was recently launched to carry out financial transactions Russian banks, which will greatly speed up the passage of payments in such a vast territory as our country. Entire satellite communications networks are being created that will make it possible to easy access Russian regional users to global information flows. Network subscribers in the regions will receive satellite channel communications the following services: fax, telephone, Internet, radio and TV programs.
Ryabukhina Elena student MBOU Sukho-Sarmatian secondary school
R presentation traces the history of appearance mobile communications.
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"Means of communication" MBOU SUKHO-SARMATSKY SOSH
A mobile phone is a telephone used in mobile communications. To date, development information technologies makes it possible to use Cell phones for the transmission, processing and storage of information and they are used as a system that performs the function of a computer, fax machine, etc. The mobile communication environment is a basic system with complex technical devices, which consists of a group of subscribers and base stations, providing subscribers with the opportunity to exchange information. In mobile communications, all information is transmitted in the form of electromagnetic waves without wires through the air. Mobile phones and the mobile communication environment
Mobile communication means Smartphone (smartphone) when transferring from in English means smart phone. Performs functions similar to a pocket computer. iPhone is a line of quad-band multimedia smartphones. The iPhone includes, in addition to the basic functions of a computer, the functions of a communicator and Internet tablets. Internet tablets are a special mobile device, which is a classic example of personal computers. Tablets consist only of a screen, and they have a built-in virtual keyboard and mouse.
MOBILE PHONE. A long time ago, these devices were placed only on warships and tanks. Today they listen to music, play, watch videos, use instead of wrist watch, notebook and camera. The fate of mobile phones is amazing - especially when you consider that it all started with boxes weighing several tens of kilograms. But after many decades of developing a mobile phone, headsets were created, a car phone from the Bell Telephone Company with two-way communication was created. (1924)
May 6, 1968 Toshiba's new video phone, model 500, is being tested at the company's headquarters in Tokyo. And so on, many different progenitors of the current mobiles were created, but there is still a long way to the current ones ... Let's start with the first mobile ...
June 13, 1983. Motorola has released the first commercial mobile phone DynaTAC 8000X. More than 10 years have been spent on its development and more than $100 million has been allocated. The phone weighed 800 grams, stored 30 phone numbers, had 1 melody and cost about $4,000. Despite this, queues formed behind him. In 1984, 300 thousand of these "mobile phones" were sold.
1989 Motorola MicroTAC 9800X - the first truly portable phone. Prior to its release, most cell phones were intended only for installation in cars due to their size, not suitable for carrying in a pocket. 1992 Motorola International 3200 is the first palm-sized digital mobile phone.
Nokia 1011 is the first mass-produced GSM phone. It was produced until 1994. 1993 The BellSouth/IBM Simon Personal Communicator was the first device to combine the functions of a telephone and a PDA.
The Nokia 9000 Communicator is the first series of smartphones with Intel processor 386. 1998 Nokia 9110i - this phone was a repetition of a series of Nokia communicators and weighed much less than its predecessor - a smartphone.
Nokia 7110 is the first mobile phone with WAP browser. Benefon Esc! - the first mobile phone model with a built-in GPS system. It was mainly sold in Europe.
Ericsson T68 - the first Ericsson phone with color screen. Sanyo SCP-5300 is the first phone with a built-in camera. Although the image was of poor quality, it was the first of its kind.
2005 year. Sony Ericsson K750 is one of the first phones with a 2 megapixel camera and widely used in Russia. O2 XDA Flame is the first PDA phone with dual core processor.
June 2007 Available from first iPhone there was an auto-rotation sensor, a multi-touch technology sensor with multi-touch capability, and a touchscreen that replaced the traditional QWERTY keyboard layout. T-Mobile phone G1 was the first device released with working system Android developed by Google. It is also known as HTC Dream. In April 2009, one million of these devices were sold.
In 2011, nearly half a billion smartphones were sold. In the last quarter of last year, their largest supplier was Apple, which sold 37.0 million devices. Pictured is the iPhone 4, released in June 2010.
Mobile operators Mobile operators are an organization that provides customers with the service of using mobile communications. Operators perform the function of collecting the necessary documents and using radio frequencies, developing their own mobile network, conditions for using the proposed mobile communications, accepting payment for services and maintenance.
Mobile phone services Conversation - after dialing mobile operator determines the location of the antenna of the calling and called subscribers. After that, the information is transmitted to the switch and the subscribers communicate through mobile network. Mobile Internet- technology for using Internet resources using mobile communications. The advantages of this type of communication is that wherever the subscriber is, he can at any time find the necessary information on the network and use the Internet services. Mobile mail - the ability of a subscriber to work with a personal electronic mailbox using mobile communications.
Bluetooth technology wireless connection with a small radius. Facilitates the process of connecting users and connecting to the Internet. SMS (Short Message Service) - a service for receiving and transmitting small text messages between subscribers in a mobile communication network. MMS (Multimedia Messaging Service) is a service for exchanging multimedia messages, photos and videos based on GPRS technology. Exchange of information using mobile communications
In the process of using mobile phones, it is necessary to observe the basic rules of ethics of communication, storage and transmission only useful information by e-mail, safety precautions for working with mobile devices. Beware and do not send indecent information over the network and by phone. Culture of use and communication using mobile phones
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Answer the questions
What is an infrastructure complex? What unites the infrastructure complex? What sectors are included in the infrastructure complex? What is the difference between the production and non-production spheres of the complex? What area of the complex can be attributed to the topic of our lesson?
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Communication is a branch of the economy that provides the reception and transmission of information.
What do you think the postal service does?
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Postal service
In the old days in Russia, communication between the capital and peripheral cities, as well as between the troops participating in hostilities, was carried out with the help of special rider messengers. This method was improved by the Tatars, having created on the roads at a distance of 30 - 40 km. special stations ("pits"), where the coachmen could rest and change horses. In the 17th century, Moscow was connected by such "pits" with Novgorod, Pskov, Smolensk, Arkhangelsk and Nizhny Novgorod. The first regular post office for sending government papers and letters from merchants was established in 1666. Under Peter I, maximum deadlines (norms) for delivering correspondence were established. Under Catherine II, a peculiar tax was introduced for letters and parcels, depending on the weight and distance of their transportation. In the 19th century, postal institutions were transferred to the Ministry of the Interior. The main function of mail was to send simple and registered letters, postcards (introduced in 1872) and parcels. Money, including copper, silver and gold coins, could be sent in small quantities in special packages and leather bags. They, like valuable parcels, were insured. Since 1897, they began to accept postal, and then telegraphic money transfers. The post office also took over the delivery of periodicals, charging for this, depending on the frequency of publication of newspapers or magazines, from 6 to 18% of the total subscription price. Electric traditional communication The following data testifies to the dynamic development of postal communication. If in 1897 in Russia there were only 2.1 thousand postal and telegraph institutions, then in 1913 their number increased to 11 thousand, and the total length of postal routes increased to 261 thousand km.
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Telephone communications
The telephone first appeared in Russia in 1880. Initially, the government planned to establish a state monopoly on telephone communications. However, due to the high cost of building and operating telephone exchanges, private capital began to be attracted to their creation. According to the concluded contracts, telephone exchanges and lines built at the expense of private companies, after 20 years of operation, became state property. By the beginning of the 20th century, there were 77 state and 11 private telephone exchanges in Russia. Telephone charges in the public sector were half those in the private sector. In total, in 1913, 300 thousand telephone sets were installed in Russian cities.
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Features of telephone communication
The main indicator of the development of the public telecommunication services market is telephone density (TP), that is, the number of telephones per 100 inhabitants, which is directly correlated with GDP per capita. According to official statistics, at the end of the 90s, the telephone fleet in Russia consisted of more than 31 million devices, that is, there were 21 telephones per 100 Russians, while the same number of residents of the United States and Western European countries - from 60 to 70 telephones . In Russia, at the beginning of the third millennium, 54,000 telephones were not installed. settlements, there were b million people on the waiting list and about 50 million potential phone owners. Tariffs for local telephone communication for the population were lower than the actual cost
Slide 7
radio and television communications
At the end of the 19th century, radio communication appeared - the wireless transmission of electrical signals over long distances using radio waves (electromagnetic waves with a frequency in the range of 105-1012 Hz). Later, powerful transmitters and sensitive receivers appeared, their sizes decreased, and their parameters improved. Significant achievements in the development of means of communication were the inventions of the phototelegraph and television communications. Video signals are transmitted with the help of these means of communication. For television communication, two transmitters are already needed: one for sound, the other for video signals. The next step in the improvement of television communications was the invention of color television.
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Telegraph communication
The first telegraph line appeared in Russia in 1835. It connected St. Petersburg with Kronstadt and was intended for the needs of the military department. Four years later, the construction of the second line was completed, which connected the northern capital with Warsaw. Since the mid-1950s, where the railways were being built, the German company Siemens has been laying a telegraph equipped with new electromagnetic technology. By the beginning of the 20th century, the length of state telegraph lines amounted to 127 thousand miles. By that time, underwater telegraph cables had been laid connecting Russia with Denmark and Sweden. Russian telegraph lines were connected to telegraph lines in China and Japan. If in 1897 14 million internal telegrams were sent, then in 1912 more than 36 million were already sent.
Slide 9
Telegram - a message sent by telegraph, one of the first types of communication using electrical transmission of information. Telegrams are transmitted, as a rule, by wire, using Morse code. Telegrams are printed on paper tape, which is then pasted onto a piece of paper for ease of reading. Telegraph (from the Greek tele - "far" + grapho - "I write") -in modern meaning- a means for transmitting a signal over wires or other telecommunication channels. Electrical new connection
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Satellite connection
Satellite communication is one of the types of radio communication based on the use of artificial earth satellites as repeaters. Satellite communication is carried out between earth stations, which can be both stationary and mobile. Network subscribers in the regions will receive the following services via satellite communication channel: fax, telephone, Internet, radio and TV programs.
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Digital communication is a field of technology related to the transmission of digital data over a distance.
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Telex communication
By 1930, the design of a start-stop telegraph apparatus equipped with a telephone-type disk dialer (teletype) was created. This type of telegraph apparatus, among other things, made it possible to personalize the subscribers of the telegraph network and to quickly connect them.
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E-mail (eng. E-mail or email, abbr. from electronic mail) - a method of transmitting information to computer networks, widely used on the Internet.
Main Feature Email: information is sent to the recipient not directly, but through an intermediate link - electronic Mailbox, which is the location on the server where the message is stored until requested by the recipient.
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cellular- one of the types of mobile radio communication, which is based on a cellular network.
Cellular phone - a mobile communication device that uses a combination of radio transmission and traditional telephone switching to carry out telephone communications in an area (coverage area) consisting of "cells" surrounding base stations cellular network. Currently, cellular communications are the most common of all types of mobile communications, which is why it is usually called a mobile phone. cellular telephone, although radiotelephones are also mobile phones in addition to cellular phones, satellite phones and trunking communication devices. Cellular communication penetration in Russia was 87%, and in Moscow and St. Petersburg it has already reached the 100% mark.
Slide 17
The number of Russians who have mobile phones at their disposal has grown from 40% in mid-2005 to 52% this year. More than half of Russians, 55%, already use telephone communications at home (there have been one percent increase over the year). According to sociologists, the number of Russians who have a computer at home is also growing - now 20% of respondents have it (15% a year ago). As the study showed, now 19% of Russians (against 17% a year ago) use personal computer daily or several times a week at home, at work and in other places, 5% - about once a week (3%), never use a computer - 73% (last year - 76%).
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Stages in the development of communications English scientist James Maxwell in 1864 theoretically predicted the existence of electromagnetic waves. The English scientist James Maxwell in 1864 theoretically predicted the existence of electromagnetic waves Heinrich Hertz discovered experimentally at the University of Berlin Heinrich Hertz discovered experimentally at the University of Berlin. May 7, 1895 A.S. Popov invented the radio. May 7, 1895 A.S. Popov invented the radio. In 1901, the Italian engineer G. Marconi made the first radio communication across the Atlantic Ocean. In 1901, the Italian engineer G. Marconi made the first radio communication across the Atlantic Ocean. B.L. Rosing May 9, 1911 electronic television. B.L. Rosing May 9, 1911 electronic television. 30 years V.K. Zworykin invented the first transmitting tube, the iconoscope. 30 years V.K. Zworykin invented the first transmitting tube, the iconoscope.
Communication is the most important link in the country's economic system, the way people communicate, the satisfaction of their industrial, spiritual, cultural and social needs - this is the most important link in the country's economic system, the way people communicate, the satisfaction of their industrial, spiritual, cultural and social needs
The main directions of development of communication facilities Radio communication Radio communication Telephone communications Telephone communications TV connection Television communication Cellular communication Cellular communication Internet Internet Space communication Space communication Phototelegraph (Fax) Phototelegraph (Fax) Video telephony Video telephony Telegraph communication Telegraph communication
Space communication SPACE COMMUNICATION, radio communication or optical (laser) communication, carried out between ground receiving and transmitting stations and spacecraft, between several ground stations predominantly via communication satellites or passive repeaters (eg belt of needles), between several spacecraft. SPACE COMMUNICATION, radio communication or optical (laser) communication carried out between ground receiving and transmitting stations and space vehicles, between several ground stations mainly through communication satellites or passive repeaters (for example, a belt of needles), between several space vehicles.
Phototelegraph Phototelegraph, the generally accepted abbreviation for facsimile communication (phototelegraph communication). A type of communication for transmitting and receiving images printed on paper (manuscripts, tables, drawings, drawings, etc.). A type of communication for transmitting and receiving images printed on paper (manuscripts, tables, drawings, drawings, etc.). The device that makes this connection. The device that makes this connection.
The first phototelegraph At the beginning of the century, the German physicist Korn created a phototelegraph, which does not fundamentally differ from modern drum scanners. (The figure on the right shows Korn's telegraph diagram and a portrait of the inventor, scanned and transmitted over a distance of more than 1000 km on November 6, 1906). At the beginning of the century, the German physicist Korn created a photo telegraph, which does not fundamentally differ from modern drum scanners. (The figure on the right shows Korn's telegraph diagram and a portrait of the inventor, scanned and transmitted over a distance of more than 1000 km on November 6, 1906).
Shelford Bidwell, British physicist, invented the "scanning telegraph". To transmit images (diagrams, maps and photographs), the system used selenium material and electrical signals. Shelford Bidwell, British physicist, invented the "scanning telegraph". To transmit images (diagrams, maps and photographs), the system used selenium material and electrical signals.
Video telephony Personal video telephony on UMTS equipment Personal video telephony on UMTS equipment The latest models of telephones have an attractive design, a rich selection of accessories, wide functionality, support for Bluetooth and wideband-ready audio technologies, as well as XML integration with any corporate applications.
Signal Line Types Two-wire line Two-wire line Electrical cable Electrical cable Metric waveguide Metric waveguide Dielectric waveguide Dielectric waveguide Radio relay line Radio relay line Beam line Beam line Optical fiber line Optical fiber line Laser communication Laser communication
Fiber-optic communication lines Fiber-optic communication lines (FOCL) are currently considered the most advanced physical medium for information transmission. Data transmission in optical fiber is based on the effect of total internal reflection. Thus, the optical signal transmitted by the laser on one side is received on the other, much more distant side. To date, a huge number of trunk fiber-optic rings, intracity and even intra-office, have been built and are being built. And this number will continue to grow. Fiber-optic communication lines (FOCL) are currently considered the most advanced physical medium for information transmission. Data transmission in optical fiber is based on the effect of total internal reflection. Thus, the optical signal transmitted by the laser on one side is received on the other, much more distant side. To date, a huge number of trunk fiber-optic rings, intracity and even intra-office, have been built and are being built. And this number will continue to grow.
Fiber-optic communication lines (FOCL) have a number of significant advantages over communication lines based on metal cables. These include: large throughput, low attenuation, small weight and dimensions, high noise immunity, reliable safety equipment, practically absent mutual influences, low cost due to the absence of non-ferrous metals in the design. FOCL uses electromagnetic waves in the optical range. Recall that visible optical radiation lies in the wavelength range nm. Practical use in the FOCL received the infrared range, i.e. radiation with a wavelength of more than 760 nm. The principle of propagation of optical radiation along an optical fiber (OF) is based on reflection from the boundary of media with different refractive indices (Fig. 5.7). Optical fiber is made of quartz glass in the form of cylinders with aligned axes and different refractive indices. The inner cylinder is called the core of the OF, and the outer layer is called the shell of the OF.
Laser communication system A rather interesting solution for high-quality and fast network communication was developed by the German company Laser2000. The two presented models look like the most ordinary video cameras and are designed for communication between offices, inside offices and along corridors. Simply put, instead of laying an optical cable, you just need to install inventions from Laser2000. However, in fact, these are not video cameras, but two transmitters that communicate with each other by means of laser radiation. Recall that a laser, unlike ordinary light, such as lamp light, is characterized by monochromaticity and coherence, that is, laser beams always have the same wavelength and scatter little. A rather curious solution for high-quality and fast network communication was developed by the German company Laser2000. The two presented models look like the most ordinary video cameras and are designed for communication between offices, inside offices and along corridors. Simply put, instead of laying an optical cable, you just need to install inventions from Laser2000. However, in fact, these are not video cameras, but two transmitters that communicate with each other by means of laser radiation. Recall that a laser, unlike ordinary light, such as lamp light, is characterized by monochromaticity and coherence, that is, laser beams always have the same wavelength and scatter little.
For the first time, laser communication between a satellite and an aircraft was carried out, Mon, 00:28, Msk The French company Astrium for the first time in the world demonstrated successful communication via a laser beam between a satellite and an aircraft. The French company Astrium has demonstrated the world's first successful laser beam communication between a satellite and an aircraft. During the tests of the laser communication system, which took place in early December 2006, communication at a distance of almost 40 thousand km was carried out twice - once the Mystere 20 aircraft was at an altitude of 6 thousand meters, the other time the flight altitude was 10 thousand meters. The speed of the aircraft was about 500 km / h, the data transfer rate for the laser beam was 50 Mb / s. The data was transmitted to the geostationary telecommunications satellite Artemis. During the tests of the laser communication system, which took place in early December 2006, communication at a distance of almost 40 thousand km was carried out twice - once the Mystere 20 aircraft was at an altitude of 6 thousand meters, the other time the flight altitude was 10 thousand meters. The speed of the aircraft was about 500 km / h, the data transfer rate for the laser beam was 50 Mb / s. The data was transmitted to the geostationary telecommunications satellite Artemis. The aircraft laser system Lola (Liaison Optique Laser Aeroportee) was used in the tests, and the Silex laser system received data on the Artemis satellite. Both systems are developed by Astrium Corporation. Lola's system, says Optics, uses a Lumics laser with a wavelength of 0.8 microns and a laser signal power of 300 mW. Avalanche photodiodes are used as photodetectors. The aircraft laser system Lola (Liaison Optique Laser Aeroportee) was used in the tests, and the Silex laser system received data on the Artemis satellite. Both systems are developed by Astrium Corporation. Lola's system, says Optics, uses a Lumics laser with a wavelength of 0.8 microns and a laser signal power of 300 mW. Avalanche photodiodes are used as photodetectors.
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