Arbeitsblatt: History of telecommunication, YW4,Unit3

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Englisch
Anderes Thema
6. Schuljahr
6 Seiten

Statistik

180014
364
4
21.03.2018

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Dominik Oertig
Land: Schweiz
Registriert vor 2006

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History of Telecommunications Telecommunications is the word we use for the science and technology of sending messages using electricity. This includes the telegraph, telephone, radio, television, and computers. These instruments change information into signals that are sent over long distances, through wires, or through optical fibers, or by radio waves, or satellite. The information can be almost anything--voices, music, pictures, words, or computer data and it arrives almost immediately. Anthropologists believe that until about 40,000 years ago humans were unable to speak as we do today. People communicated by grunting and gesturing, possibly imitating sounds found in nature. Early humans also painted and drew pictures of things they saw. Thousands of years after language developed, evidence of early writing appears. People living in the ancient Near East wrote using symbols or pictographs and later developed alphabets. They could now document their histories and pass on news and information. Imagine living before the invention of electronic communication. You would be living without telephones, radio, television and computers. Most of our entertainment depends upon telecommunications. Yes, thats right, if you lived two hundred years ago, before telecommunications, you would receive messages as handwritten letters delivered by people on foot or on horseback. You would be living without television, the worlds most popular form of entertainment. Telegraph and Telephone The first reliable electronic telegraph machines were built in the 1830s when an American named Samuel Morse developed telegraph system designed to use code of long and short pulses of electric current representing different letters. The code became known as Morse code. To send message, an operator pressed switch, sending signal, which sent an electric current along wire to the receiving machine. PICTURED ABOVE: Alexander Graham Bell, 1 Telegraphs required wires or cable, so in order to send telegrams (the name for the actual messages) across the ocean, the necessary cable was laid and telegrams could be sent between Europe and the United States. The telephone quickly took over from the telegraph. In 1876, Alexander Graham Bell, Scottish doctor, was working on new type of telegraph when he accidentally spilled something on his clothes and called for his assistant, who was able to hear his voice over the wire. Like the telegraph, telephone uses electricity flowing through wires, but it sends sounds instead of codes. When you speak into telephone, the receiver changes your voice into an electric current and then changes the current back into voice again at the other end. The ability to have two-way conversations by telephone over distance brought people closer together. History of Radio The next advancement in telecommunications was radio, the first wireless mode of communication. Radios send messages by radio waves instead of wires. German scientist Heinrich Hertz proved the existence of radio waves, which occur in nature. In 1895, young Italian named Gugliemo Marconi invented what he called the wireless telegraph while experimenting in his parents attic. He used radio waves to transmit Morse code and the instrument he used became known as the radio. In 1906, Marconi shared the Nobel Prize for physics with Ferdinand Braun, German, in recognition of their contributions to the development of wireless telegraphy. Radio works by changing sounds or signals into radio waves, which travel through air, space, and solid objects, and the radio receiver changes them back into the sounds, words, and music we hear. radio broadcast is one-way transmission, originating from radio station. In the early 1920s, radio played an important role in peoples lives, and over 500 stations were broadcasting news, music, sports, drama, and variety shows. By the 1930s, most households in the U.S. and Europe had at least one radio. In the evening, the family gathered around big console that was usually located in the living room, where they might spend hours listening to variety shows or comedies from favorites like Jack Benny or Edgar Bergen and Charlie McCarthy. Everyone used their imagination to visualize all of the characters in their favorite shows. This was the beginning of the Golden Age of Radio. Television Invention Television is way of sending and receiving moving images and sounds over wires or through the air by electrical impulses. The big breakthrough in technology was the ability to send sound and pictures over the air. The word television comes from the Greek prefix tele and the Latin word vision or seeing from distance. The TV camera converts images into electrical impulses, which are sent along cables, or by radio waves, or satellite to television receiver where they are changed back into picture. As with most inventions, televisions development depended upon previous inventions, and more than one individual contributed to the development of television, as we know it today. People started experimenting with television during the 19th century. When you ask the question--who invented television, you may get few different answers. Philo Farnsworth successfully demonstrated electronic television in San Francisco, in 1927. Farnsworth, at the age of fifteen, began imagining ways that electronic television could work. One day while working in the fields among rows of vegetables, he was inspired. He realized that picture could be dissected by simple television camera into series of lines of electricity. The lines would be transmitted so quickly that the eyes would merge the lines. Then, cathode ray tube television receiver would change those lines back into picture. Initially, television was available only in black and white, even though experiments with color began in the 1920s; however, you could not buy color television until 1953. Nobel laureate Ferdinand Braun invented the cathode ray tube, the basis of all modern television cameras and receivers. Mobile Phone Mobile phones in the 1950s through 1970s were large and heavy, and most were built into cars. In the late 20th century technology improved so people could carry their phones easily. Although Dr. Martin Cooper from Motorola made the first call using mobile phone in 1973, it did not use the type of cellular mobile phone network that we use today. The first mobile phone networks were created in the late 1970s in Japan. Now almost all urban areas, and many country areas, are covered by mobile phone networks. cell phone combines technologies, mainly telephone, radio, and computer. Most also have digital camera inside. Cell phones work as two-way radios. They send electromagnetic microwaves from base station to base station. The waves are sent through antennas. This is called wireless communication. Early cell telephones used analog networks. They became rare late in the 20th century. Modern phones use digital networks. The first digital networks are also known as second generation, or 2G, technologies. The most used digital network is GSM (Global System for Mobile communication). It is used mainly in Europe and Asia, while CDMA (Code-Division Multiple Access) networks are mainly used in North America. The difference is in communication protocol. Other countries like Japan have different 2G protocols. few 2G networks are still used. 3G are more common, and many places have 4G. The radio waves that the mobile phone networks use are split into different frequencies. The frequency is measured in Hz. Low frequencies can send the signal farther. Higher frequencies provide better connections and the voice communications are generally clearer. Smartphones majority of new mobile phones from the 21st century are smartphones. These phones can be used for email, browsing the internet, playing music and games,and many other functions that computers can perform. This is because mobile phones basically are small computers. Older phones also used computer technology, but lacked many of the parts of computer that were too big to fit into phone. Modern phone makers have been able to use smaller parts. Most smartphones are also GPS receivers and digital cameras. Examples of smartphones include Apple iPhone and Samsung Galaxy series.