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85-843: Emtel Ltd. is a telecommunications company based in Ebene City , Mauritius . Launched on 29 May 1989 – Emtel Ltd became the first mobile telephony operator in the Southern Hemisphere . This took place under the aegis of The Currimjee Jeewanjee Group . Indian conglomerate Bharti Enterprises acquired a 25% stake in Emtel on 27 April 2015 through its subsidiary, Indian Continent Investment Limited (ICIL). In 1999, Emtel launched its GSM service offerings, three years after its competitor mainly because of exclusive rights allocated to Cellplus Ltd to operate GSM technology in Mauritius. As such, Emtel experienced

170-412: A thermionic tube or thermionic valve uses thermionic emission of electrons from a heated cathode for a number of fundamental electronic functions such as signal amplification and current rectification . The simplest vacuum tube, the diode invented in 1904 by John Ambrose Fleming , contains only a heated electron-emitting cathode and an anode. Electrons can only flow in one direction through

255-463: A PhD from the University of Pittsburgh , his experiments were directed at improving the output of photoelectric cells. There were, however, limits to how far one could go along these lines, and so, in 1929, Zworykin returned to vibrating mirrors and facsimile transmission, filing patents describing these. At this time, however, he was also experimenting with an improved cathode ray receiving tube, filing

340-594: A Zworykin Award , the prize being travelling funds to the award's presentation at a World Congress. Zworykin died on July 29, 1982, in Princeton, New Jersey . His wife Katherine died on February 18, 1985. Throughout his steady rise in rank, Zworykin remained involved in the many important developments of RCA and received several outstanding honours, including, in 1934, the Morris Liebmann Memorial Prize from

425-411: A radio broadcasting station , the station's large power amplifier is the transmitter and the broadcasting antenna is the interface between the power amplifier and the free space channel. The free space channel is the transmission medium and the receiver's antenna is the interface between the free space channel and the receiver. Next, the radio receiver is the destination of the radio signal, where it

510-656: A Russian-born professor of bacteriology at the University of Pennsylvania . It was the second marriage for both. The ceremony was in Burlington, New Jersey . A photographic record of his marriage and worldwide tour can be viewed online. He retired in 1954. New frontiers in medical engineering and biological engineering appealed to him, and he became a founder and first president of the International Federation for Medical and Biological Engineering . The Federation continues to honor outstanding research engineering with

595-411: A better price for their goods. In Côte d'Ivoire , coffee growers share mobile phones to follow hourly variations in coffee prices and sell at the best price. On the macroeconomic scale, Lars-Hendrik Röller and Leonard Waverman suggested a causal link between good telecommunication infrastructure and economic growth. Few dispute the existence of a correlation although some argue it is wrong to view

680-438: A caveat for it in 1876. Gray abandoned his caveat and because he did not contest Bell's priority, the examiner approved Bell's patent on March 3, 1876. Gray had filed his caveat for the variable resistance telephone, but Bell was the first to document the idea and test it in a telephone.[88] Antonio Meucci invented a device that allowed the electrical transmission of voice over a line nearly 30 years before in 1849, but his device

765-441: A connection between two or more users. For both types of networks, repeaters may be necessary to amplify or recreate the signal when it is being transmitted over long distances. This is to combat attenuation that can render the signal indistinguishable from the noise. Another advantage of digital systems over analogue is that their output is easier to store in memory, i.e., two voltage states (high and low) are easier to store than

850-495: A continuous range of states. Telecommunication has a significant social, cultural and economic impact on modern society. In 2008, estimates placed the telecommunication industry 's revenue at US$ 4.7 trillion or just under three per cent of the gross world product (official exchange rate). Several following sections discuss the impact of telecommunication on society. On the microeconomic scale, companies have used telecommunications to help build global business empires. This

935-442: A functioning transmitter tube before 1931. Farnsworth had lost two interference claims to Zworykin in 1928, but this time he prevailed and the U.S. Patent Office rendered a decision in 1934 awarding priority of the invention of the image dissector to Farnsworth. RCA lost a subsequent appeal, but litigation over a variety of issues continued for several years with Sarnoff finally agreeing to pay Farnsworth royalties. Zworykin received

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1020-406: A higher-frequency signal (known as the " carrier wave ") before transmission. There are several different modulation schemes available to achieve this [two of the most basic being amplitude modulation (AM) and frequency modulation (FM)]. An example of this process is a disc jockey's voice being impressed into a 96 MHz carrier wave using frequency modulation (the voice would then be received on

1105-450: A key advantage of digital signals over analogue signals. However, digital systems fail catastrophically when noise exceeds the system's ability to autocorrect. On the other hand, analogue systems fail gracefully: as noise increases, the signal becomes progressively more degraded but still usable. Also, digital transmission of continuous data unavoidably adds quantization noise to the output. This can be reduced, but not eliminated, only at

1190-792: A new international frequency list and used in conformity with the Radio Regulation". According to the ITU's Radio Regulations adopted in Atlantic City, all frequencies referenced in the International Frequency Registration Board , examined by the board and registered on the International Frequency List "shall have the right to international protection from harmful interference". From a global perspective, there have been political debates and legislation regarding

1275-690: A patent application for this in November 1929, and introducing the new receiver that he named the "kinescope", reading a paper two days later at a convention of the Institute of Radio Engineers . Having developed the prototype of the receiver by December, Zworykin met David Sarnoff , who eventually hired him and put him in charge of television development for the Radio Corporation of America (RCA) at its factories and laboratories in Camden, New Jersey . The move to

1360-526: A patent in 1928 for a color transmission version of his 1923 patent application; he also divided his original application in 1931, receiving a patent in 1935, while a second one was eventually issued in 1938 by the Court of Appeals on a non-Farnsworth-related interference case, and over the objection of the Patent Office. Zworykin married for a second time in 1951. His wife was Katherine Polevitzky (1888–1985),

1445-437: A person's age, interests, sexual preference and relationship status. In this way, these sites can play important role in everything from organising social engagements to courtship . Prior to social networking sites, technologies like short message service (SMS) and the telephone also had a significant impact on social interactions. In 2000, market research group Ipsos MORI reported that 81% of 15- to 24-year-old SMS users in

1530-491: A radio as the channel "96 FM"). In addition, modulation has the advantage that it may use frequency division multiplexing (FDM). A telecommunications network is a collection of transmitters, receivers, and communications channels that send messages to one another. Some digital communications networks contain one or more routers that work together to transmit information to the correct user. An analogue communications network consists of one or more switches that establish

1615-469: A service that operated for a year until the gap in the telegraph link was closed. In the Middle Ages, chains of beacons were commonly used on hilltops as a means of relaying a signal. Beacon chains suffered the drawback that they could only pass a single bit of information, so the meaning of the message such as "the enemy has been sighted" had to be agreed upon in advance. One notable instance of their use

1700-633: A significant decline in market share at the end of the 1990s. In August 2017, Emtel won its long going legal case against the ICTA/MT/Cellplus. The Supreme Court of Mauritius ruled exclusive rights to Cellplus as unfair competition and defendants should compensate Emtel Ltd Rs 554,190,000. The company now supplies a range of telecommunication services. In November 2004, Emtel became the first company in Africa to launch 3G /UMTS services. In May 2012, following its 23rd anniversary, Emtel launched 4G[LTE] and became

1785-442: A single medium to transmit several concurrent communication sessions . Several methods of long-distance communication before the modern era used sounds like coded drumbeats , the blowing of horns , and whistles . Long-distance technologies invented during the 20th and 21st centuries generally use electric power, and include the telegraph , telephone , television , and radio . Early telecommunication networks used metal wires as

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1870-411: A telephone network, the caller is connected to the person to whom they wish to talk by switches at various telephone exchanges . The switches form an electrical connection between the two users and the setting of these switches is determined electronically when the caller dials the number. Once the connection is made, the caller's voice is transformed to an electrical signal using a small microphone in

1955-412: A version of the electrical telegraph that he unsuccessfully demonstrated on September 2, 1837. His code was an important advance over Wheatstone's signaling method. The first transatlantic telegraph cable was successfully completed on July 27, 1866, allowing transatlantic telecommunication for the first time. The conventional telephone was patented by Alexander Bell in 1876. Elisha Gray also filed

2040-577: Is adapted from the French, because its written use was recorded in 1904 by the French engineer and novelist Édouard Estaunié . Communication was first used as an English word in the late 14th century. It comes from Old French comunicacion (14c., Modern French communication), from Latin communicationem (nominative communication), noun of action from past participle stem of communicare, "to share, divide out; communicate, impart, inform; join, unite, participate in," literally, "to make common", from communis". At

2125-671: Is called point-to-point communication because it occurs between a transmitter and a receiver. Telecommunication through radio broadcasts is called broadcast communication because it occurs between a powerful transmitter and numerous low-power but sensitive radio receivers. Telecommunications in which multiple transmitters and multiple receivers have been designed to cooperate and share the same physical channel are called multiplex systems . The sharing of physical channels using multiplexing often results in significant cost reduction. Multiplexed systems are laid out in telecommunication networks and multiplexed signals are switched at nodes through to

2210-451: Is called (in the jargon of the field) " quadrature amplitude modulation " (QAM) that are used in high-capacity digital radio communication systems. Modulation can also be used to transmit the information of low-frequency analogue signals at higher frequencies. This is helpful because low-frequency analogue signals cannot be effectively transmitted over free space. Hence the information from a low-frequency analogue signal must be impressed into

2295-434: Is commonly called "keying" —a term derived from the older use of Morse Code in telecommunications—and several keying techniques exist (these include phase-shift keying , frequency-shift keying , and amplitude-shift keying ). The " Bluetooth " system, for example, uses phase-shift keying to exchange information between various devices. In addition, there are combinations of phase-shift keying and amplitude-shift keying which

2380-794: Is converted from electricity to sound. Telecommunication systems are occasionally "duplex" (two-way systems) with a single box of electronics working as both the transmitter and a receiver, or a transceiver (e.g., a mobile phone ). The transmission electronics and the receiver electronics within a transceiver are quite independent of one another. This can be explained by the fact that radio transmitters contain power amplifiers that operate with electrical powers measured in watts or kilowatts, but radio receivers deal with radio powers measured in microwatts or nanowatts . Hence, transceivers have to be carefully designed and built to isolate their high-power circuitry and their low-power circuitry from each other to avoid interference. Telecommunication over fixed lines

2465-481: Is degraded by undesirable noise . Commonly, the noise in a communication system can be expressed as adding or subtracting from the desirable signal via a random process . This form of noise is called additive noise , with the understanding that the noise can be negative or positive at different instances. Unless the additive noise disturbance exceeds a certain threshold, the information contained in digital signals will remain intact. Their resistance to noise represents

2550-609: Is self-evident in the case of online retailer Amazon.com but, according to academic Edward Lenert, even the conventional retailer Walmart has benefited from better telecommunication infrastructure compared to its competitors. In cities throughout the world, home owners use their telephones to order and arrange a variety of home services ranging from pizza deliveries to electricians. Even relatively poor communities have been noted to use telecommunication to their advantage. In Bangladesh 's Narsingdi District , isolated villagers use cellular phones to speak directly to wholesalers and arrange

2635-448: Is separated from its adjacent stations by 200 kHz, and the difference between 200 kHz and 180 kHz (20 kHz) is an engineering allowance for the imperfections in the communication system. In the example above, the "free space channel" has been divided into communications channels according to frequencies , and each channel is assigned a separate frequency bandwidth in which to broadcast radio waves. This system of dividing

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2720-449: Is the informational equivalent of two newspaper pages per person per day in 1986, and six entire newspapers per person per day by 2007. Given this growth, telecommunications play an increasingly important role in the world economy and the global telecommunications industry was about a $ 4.7 trillion sector in 2012. The service revenue of the global telecommunications industry was estimated to be $ 1.5 trillion in 2010, corresponding to 2.4% of

2805-569: Is the transmission of information with an immediacy comparable to face-to-face communication. As such, slow communications technologies like postal mail and pneumatic tubes are excluded from the definition. Many transmission media have been used for telecommunications throughout history, from smoke signals , beacons , semaphore telegraphs , signal flags , and optical heliographs to wires and empty space made to carry electromagnetic signals. These paths of transmission may be divided into communication channels for multiplexing , allowing for

2890-812: The Faraday Medal from Great Britain (1965), and a member of the U.S. National Hall of Fame from 1977. He received the first Eduard Rhein Ring of Honor from the German Eduard Rhein Foundation in 1980. From 1952 to 1986, the IEEE made awards to worthy engineers in the name of Vladimir K. Zworykin. More recently the Zworykin Award has been bestowed by the International Federation for Medical and Biological Engineering . The most complete list of Zworykin's awards can be found online at historyTV.net . Zworykin

2975-693: The Institute of Radio Engineers . In 1941, he was elected to the American Academy of Arts and Sciences . He was awarded the Howard N. Potts Medal from The Franklin Institute in 1947. He was elected to the American Philosophical Society in 1948. He was named honorary vice president of RCA in 1954. In 1966, the National Academy of Sciences , of which he was a member, awarded him

3060-589: The National Medal of Science for his contributions to the instruments of science, engineering, and television and for his stimulation of the application of engineering to medicine. In 1967, Zworykin received the Golden Plate Award of the American Academy of Achievement . He was founder-president of the International Federation for Medical Electronics and Biological Engineering, a recipient of

3145-756: The Nipkow disk by Paul Nipkow and thus became known as the mechanical television . It formed the basis of experimental broadcasts done by the British Broadcasting Corporation beginning on 30 September 1929. However, for most of the 20th century, televisions depended on the cathode ray tube invented by Karl Ferdinand Braun . The first version of such a television to show promise was produced by Philo Farnsworth and demonstrated to his family on 7 September 1927. After World War II, interrupted experiments resumed and television became an important home entertainment broadcast medium. The type of device known as

3230-720: The River Ob to the Arctic Ocean as part of an expedition led by Russian scientist Innokenty P. Tolmachev , eventually arriving in the U.S. at the end of 1918. He returned to Omsk , then capital of Admiral Kolchak 's government in 1919, via Vladivostok , then to the United States again on official duties from the Omsk government . These duties ended with the collapse of the White movement in Siberia at

3315-551: The St. Petersburg Institute of Technology , under Boris Rosing . He helped Rosing with experimental work on television in the basement of Rosing's private lab at the School of Artillery of Saint Petersburg . They worked on the problem of "electrical telescopy," something Zworykin had never heard of before. At this time, electrical telescopy (or television as it was later called) was just a dream. Zworykin did not know that others had been studying

3400-440: The spark gap transmitter for radio or mechanical computers for computing, it was the invention of the thermionic vacuum tube that made these technologies widespread and practical, leading to the creation of electronics . In the 1940s, the invention of semiconductor devices made it possible to produce solid-state devices, which are smaller, cheaper, and more efficient, reliable, and durable than thermionic tubes. Starting in

3485-671: The 1932 Plenipotentiary Telegraph Conference and the International Radiotelegraph Conference in Madrid, the two organizations merged to form the International Telecommunication Union (ITU). They defined telecommunication as "any telegraphic or telephonic communication of signs, signals, writing, facsimiles and sounds of any kind, by wire, wireless or other systems or processes of electric signaling or visual signaling (semaphores)." The definition

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3570-492: The 1970s. In the 1960s, Paul Baran and, independently, Donald Davies started to investigate packet switching , a technology that sends a message in portions to its destination asynchronously without passing it through a centralized mainframe . A four-node network emerged on 5 December 1969, constituting the beginnings of the ARPANET , which by 1981 had grown to 213 nodes . ARPANET eventually merged with other networks to form

3655-603: The French and British patents of 1928 priority by the Hungarian inventor Kálmán Tihanyi whom the company had approached in July 1930, after the publication of his patents in England and France. This was a curious design, one where the scanning electron beam would strike the photoelectric cell from the same side where the optical image was cast. Even more importantly, it was a system characterized by an operation based on an entirely new principle,

3740-461: The ITU was able to compile an index that measures the overall ability of citizens to access and use information and communication technologies. Using this measure, Sweden, Denmark and Iceland received the highest ranking while the African countries Niger , Burkina Faso and Mali received the lowest. Telecommunication has played a significant role in social relationships. Nevertheless, devices like

3825-726: The Internet. While Internet development was a focus of the Internet Engineering Task Force (IETF) who published a series of Request for Comments documents, other networking advancements occurred in industrial laboratories , such as the local area network (LAN) developments of Ethernet (1983), Token Ring (1984) and Star network topology. The effective capacity to exchange information worldwide through two-way telecommunication networks grew from 281 petabytes (PB) of optimally compressed information in 1986 to 471 PB in 1993 to 2.2 exabytes (EB) in 2000 to 65 EB in 2007. This

3910-519: The RCA's Camden laboratories occurred in the spring of 1930, and the difficult task of developing a transmitter could begin. There was an in-house evaluation in mid-1930, where the kinescope performed well (but with only 60 lines definition), and the transmitter was still of a mechanical type. A "breakthrough" would come when the Zworykin team decided to develop a new type of cathode ray transmitter, one described in

3995-499: The United Kingdom had used the service to coordinate social arrangements and 42% to flirt. In cultural terms, telecommunication has increased the public's ability to access music and film. With television, people can watch films they have not seen before in their own home without having to travel to the video store or cinema. With radio and the Internet, people can listen to music they have not heard before without having to travel to

4080-692: The United States was spent on media that depend upon telecommunication. Many countries have enacted legislation which conforms to the International Telecommunication Regulations established by the International Telecommunication Union (ITU), which is the "leading UN agency for information and communication technology issues". In 1947, at the Atlantic City Conference, the ITU decided to "afford international protection to all frequencies registered in

4165-551: The caller's handset . This electrical signal is then sent through the network to the user at the other end where it is transformed back into sound by a small speaker in that person's handset. Vladimir K. Zworykin Vladimir Zworykin was born in Murom , Russia, in 1888 or 1889, to the family of a prosperous merchants . He had a relatively calm upbringing, and he rarely saw his father except on religious holidays. He studied at

4250-437: The correct destination terminal receiver. Communications can be encoded as analogue or digital signals , which may in turn be carried by analogue or digital communication systems. Analogue signals vary continuously with respect to the information, while digital signals encode information as a set of discrete values (e.g., a set of ones and zeroes). During propagation and reception, information contained in analogue signals

4335-533: The death of Kolchak. Zworykin then decided to remain permanently in the United States. Once in the U.S., Zworykin found work at the Westinghouse laboratories in Pittsburgh where he eventually had an opportunity to engage in television experiments. Zworykin applied for a television patent in the U.S. in 1923. He summarized the resulting invention in two patent applications. The first, entitled "Television Systems",

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4420-511: The development of optical fibre. The Internet , a technology independent of any given medium, has provided global access to services for individual users and further reduced location and time limitations on communications. Telecommunication is a compound noun of the Greek prefix tele- (τῆλε), meaning distant , far off , or afar , and the Latin verb communicare , meaning to share . Its modern use

4505-537: The device—from the cathode to the anode. Adding one or more control grids within the tube enables the current between the cathode and anode to be controlled by the voltage on the grid or grids. These devices became a key component of electronic circuits for the first half of the 20th century and were crucial to the development of radio, television, radar, sound recording and reproduction , long-distance telephone networks, and analogue and early digital computers . While some applications had used earlier technologies such as

4590-696: The early 1930s). Zworykin graduated in 1912. He then studied X-rays under professor Paul Langevin in Paris. During World War I , Zworykin was enlisted and served in the Russian Signal Corps. He then worked testing radio equipment that was being produced for the Russian Army. Zworykin left Russia for the United States in 1918 during the Russian Civil War . He left through Siberia , travelling north on

4675-422: The electrical telegraph, the last commercial line was abandoned in 1880. On July 25, 1837, the first commercial electrical telegraph was demonstrated by English inventor Sir William Fothergill Cooke and English scientist Sir Charles Wheatstone . Both inventors viewed their device as "an improvement to the [existing] electromagnetic telegraph" and not as a new device. Samuel Morse independently developed

4760-403: The expense of increasing the channel bandwidth requirement. The term "channel" has two different meanings. In one meaning, a channel is the physical medium that carries a signal between the transmitter and the receiver. Examples of this include the atmosphere for sound communications, glass optical fibres for some kinds of optical communications , coaxial cables for communications by way of

4845-521: The first fully operational LTE provider in Mauritius. The company now operates GSM , GPRS , 3G/UMTS as well as 3.5G/ HSDPA , 4G/[LTE] and WIMAX networks. Emtel also offers Internet and international connectivity via undersea Optical fibre and Data Centre Services. In June 2015, Emtel launched the first Fibre Through The Air (FTTA) of the region. More than 400,000 television service subscribers. Telecommunications Telecommunication , often used in its plural form or abbreviated as telecom ,

4930-498: The idea since the 1880s, or that Professor Rosing had been working on it in secret since 1902 and had made excellent progress. Rosing had filed his first patent on a television system in 1907, featuring a very early cathode-ray tube as a receiver, and a mechanical device as a transmitter. Its demonstration in 1911, based on an improved design, was the world's first demonstration of TV of any kind. Zworykin married Tatiana Vasilieva in 1916, they had two daughters (the couple separated in

5015-431: The importance of social conversations and staying connected to family and friends. Since then the role that telecommunications has played in social relations has become increasingly important. In recent years, the popularity of social networking sites has increased dramatically. These sites allow users to communicate with each other as well as post photographs, events and profiles for others to see. The profiles can list

5100-552: The management of telecommunication and broadcasting. The history of broadcasting discusses some debates in relation to balancing conventional communication such as printing and telecommunication such as radio broadcasting. The onset of World War II brought on the first explosion of international broadcasting propaganda. Countries, their governments, insurgents, terrorists, and militiamen have all used telecommunication and broadcasting techniques to promote propaganda. Patriotic propaganda for political movements and colonization started

5185-474: The medium for transmitting signals. These networks were used for telegraphy and telephony for many decades. In the first decade of the 20th century, a revolution in wireless communication began with breakthroughs including those made in radio communications by Guglielmo Marconi , who won the 1909 Nobel Prize in Physics . Other early pioneers in electrical and electronic telecommunications include co-inventors of

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5270-567: The medium into channels according to frequency is called " frequency-division multiplexing ". Another term for the same concept is " wavelength-division multiplexing ", which is more commonly used in optical communications when multiple transmitters share the same physical medium. Another way of dividing a communications medium into channels is to allocate each sender a recurring segment of time (a "time slot", for example, 20 milliseconds out of each second), and to allow each sender to send messages only within its own time slot. This method of dividing

5355-414: The medium into communication channels is called " time-division multiplexing " ( TDM ), and is used in optical fibre communication. Some radio communication systems use TDM within an allocated FDM channel. Hence, these systems use a hybrid of TDM and FDM. The shaping of a signal to convey information is known as modulation . Modulation can be used to represent a digital message as an analogue waveform. This

5440-727: The mid-1930s. In 1936, the BBC broadcast propaganda to the Arab World to partly counter similar broadcasts from Italy, which also had colonial interests in North Africa. Modern political debates in telecommunication include the reclassification of broadband Internet service as a telecommunications service (also called net neutrality ), regulation of phone spam , and expanding affordable broadband access. According to data collected by Gartner and Ars Technica sales of main consumer's telecommunication equipment worldwide in millions of units was: In

5525-584: The mid-1960s, thermionic tubes were replaced with the transistor . Thermionic tubes still have some applications for certain high-frequency amplifiers. On 11 September 1940, George Stibitz transmitted problems for his Complex Number Calculator in New York using a teletype and received the computed results back at Dartmouth College in New Hampshire . This configuration of a centralized computer ( mainframe ) with remote dumb terminals remained popular well into

5610-452: The music store. Telecommunication has also transformed the way people receive their news. A 2006 survey (right table) of slightly more than 3,000 Americans by the non-profit Pew Internet and American Life Project in the United States the majority specified television or radio over newspapers. Telecommunication has had an equally significant impact on advertising. TNS Media Intelligence reported that in 2007, 58% of advertising expenditure in

5695-400: The neighbourhood of 94.5  MHz (megahertz) while another radio station can simultaneously broadcast radio waves at frequencies in the neighbourhood of 96.1 MHz. Each radio station would transmit radio waves over a frequency bandwidth of about 180  kHz (kilohertz), centred at frequencies such as the above, which are called the "carrier frequencies" . Each station in this example

5780-515: The presence or absence of an atmosphere between the two. Radio waves travel through a perfect vacuum just as easily as they travel through air, fog, clouds, or any other kind of gas. The other meaning of the term "channel" in telecommunications is seen in the phrase communications channel , which is a subdivision of a transmission medium so that it can be used to send multiple streams of information simultaneously. For example, one radio station can broadcast radio waves into free space at frequencies in

5865-553: The principle of the accumulation and storage of charges during the entire time between two scansions by the cathode-ray beam. According to Albert Abramson, Zworykin's experiments started in April 1931, and after the achievement of the first promising experimental transmitters, on October 23, 1931, it was decided that the new camera tube would be named the iconoscope . Zworykin first presented his iconoscope to RCA in 1932. He continued work on it, and "[t]he image iconoscope, presented in 1934,

5950-709: The relationship as causal. Because of the economic benefits of good telecommunication infrastructure, there is increasing worry about the inequitable access to telecommunication services amongst various countries of the world—this is known as the digital divide . A 2003 survey by the International Telecommunication Union (ITU) revealed that roughly a third of countries have fewer than one mobile subscription for every 20 people and one-third of countries have fewer than one land-line telephone subscription for every 20 people. In terms of Internet access, roughly half of all countries have fewer than one out of 20 people with Internet access. From this information, as well as educational data,

6035-604: The telegraph Charles Wheatstone and Samuel Morse , numerous inventors and developers of the telephone including Antonio Meucci , Philipp Reis , Elisha Gray and Alexander Graham Bell , inventors of radio Edwin Armstrong and Lee de Forest , as well as inventors of television like Vladimir K. Zworykin , John Logie Baird and Philo Farnsworth . Since the 1960s, the proliferation of digital technologies has meant that voice communications have gradually been supplemented by data. The physical limitations of metallic media prompted

6120-412: The telephone system were originally advertised with an emphasis on the practical dimensions of the device (such as the ability to conduct business or order home services) as opposed to the social dimensions. It was not until the late 1920s and 1930s that the social dimensions of the device became a prominent theme in telephone advertisements. New promotions started appealing to consumers' emotions, stressing

6205-609: The then-newly discovered phenomenon of radio waves , demonstrating, by 1901, that they could be transmitted across the Atlantic Ocean. This was the start of wireless telegraphy by radio. On 17 December 1902, a transmission from the Marconi station in Glace Bay, Nova Scotia, Canada , became the world's first radio message to cross the Atlantic from North America. In 1904, a commercial service

6290-490: The voltages and electric currents in them, and free space for communications using visible light , infrared waves, ultraviolet light , and radio waves . Coaxial cable types are classified by RG type or "radio guide", terminology derived from World War II. The various RG designations are used to classify the specific signal transmission applications. This last channel is called the "free space channel". The sending of radio waves from one place to another has nothing to do with

6375-488: The wartime purposes of aircraft and land communication, radio navigation, and radar. Development of stereo FM broadcasting of radio began in the 1930s in the United States and the 1940s in the United Kingdom, displacing AM as the dominant commercial standard in the 1970s. On March 25, 1925, John Logie Baird demonstrated the transmission of moving pictures at the London department store Selfridges . Baird's device relied upon

6460-418: The world's gross domestic product (GDP). Modern telecommunication is founded on a series of key concepts that experienced progressive development and refinement in a period of well over a century: Telecommunication technologies may primarily be divided into wired and wireless methods. Overall, a basic telecommunication system consists of three main parts that are always present in some form or another: In

6545-488: Was a result of a collaboration between Zworykin and RCA's licensee Telefunken . ... In 1935 the Reichspost started the public broadcastings using this tube and applying a 180 lines system." RCA filed an interference suit against rival television scientist Philo Farnsworth , claiming Zworykin's 1923 patent had priority over Farnsworth's design, despite the fact it could present no evidence that Zworykin had actually produced

6630-483: Was during the Spanish Armada , when a beacon chain relayed a signal from Plymouth to London . In 1792, Claude Chappe , a French engineer, built the first fixed visual telegraphy system (or semaphore line ) between Lille and Paris. However semaphore suffered from the need for skilled operators and expensive towers at intervals of ten to thirty kilometres (six to nineteen miles). As a result of competition from

6715-407: Was established to transmit nightly news summaries to subscribing ships, which incorporated them into their onboard newspapers. World War I accelerated the development of radio for military communications . After the war, commercial radio AM broadcasting began in the 1920s and became an important mass medium for entertainment and news. World War II again accelerated the development of radio for

6800-540: Was filed on December 29, 1923, and was followed by a second application in 1925 of essentially the same content, but with minor changes and the addition of a Paget-type RGB  raster screen for color transmission and reception. He was awarded a patent for the 1925 application in 1928, and two patents for the 1923 application that was divided in 1931, although the equipment described was never successfully demonstrated. Zworykin described cathode-ray tubes as both transmitter and receiver. The operation, whose basic thrust

6885-586: Was inducted into the New Jersey Inventor's Hall of Fame and the National Inventors Hall of Fame . Additionally, Tektronix in Beaverton, Oregon has named a street on its campus after Zworykin. In 1995 University of Illinois Press published Zworykin, Pioneer of Television by Albert Abramson. In 2010 Leonid Parfyonov produced a documentary film "Zvorykin-Muromets" about Zworykin. Zworykin

6970-462: Was later reconfirmed, according to Article 1.3 of the ITU Radio Regulations , which defined it as "Any transmission , emission or reception of signs, signals, writings, images and sounds or intelligence of any nature by wire , radio, optical, or other electromagnetic systems". Homing pigeons have been used throughout history by different cultures. Pigeon post had Persian roots and

7055-657: Was later used by the Romans to aid their military. Frontinus claimed Julius Caesar used pigeons as messengers in his conquest of Gaul . The Greeks also conveyed the names of the victors at the Olympic Games to various cities using homing pigeons. In the early 19th century, the Dutch government used the system in Java and Sumatra . And in 1849, Paul Julius Reuter started a pigeon service to fly stock prices between Aachen and Brussels ,

7140-476: Was of little practical value because it relied on the electrophonic effect requiring users to place the receiver in their mouths to "hear". The first commercial telephone services were set up by the Bell Telephone Company in 1878 and 1879 on both sides of the Atlantic in the cities of New Haven and London. In 1894, Italian inventor Guglielmo Marconi began developing a wireless communication using

7225-727: Was to prevent the emission of electrons between scansion cycles, was reminiscent of A. A. Campbell Swinton 's proposal published in Nature in June 1908. The demonstration given (sometime in late 1925 or early 1926) by Zworykin was far from a success with the Westinghouse management, even though it showed the possibilities inherent in a system based on the cathode-ray tube. He was told by management to "devote his time to more practical endeavours," yet continued his efforts to perfect his system. As attested by his doctoral dissertation of 1926, earning him

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