1、 中文 4700 字 本科毕业设计（论文） 英文 翻译 题 目 学生姓名 专业班级 通信工程 05-2 学 号 12 院 （系） 计算机与通信工程学院 指导教师 完成时间 2009 年 4 月 26 日 1 英文原文 : Data communications Gildas Avoine and Philippe Oechslin EPFL, Lausanne, Switzerland fgildas.avoine, philippe.oechslingep.ch Abstract Data communications are communications and computer tech
2、nology resulting from the combination of a new means of communication. To transfer information between the two places must have transmission channel, according to the different transmission media, there is wired data communications and wireless data communications division. But they are through the
3、transmission channel data link terminals and computers, different locations of implementation of the data terminal software and hardware and the sharing of information resources. 1 The development of data communications The first phase: the main language, through the human, horsepower, war and other
4、 means of transmission of original information. Phase II: Letter Post. (An increase means the dissemination of information) The third stage: printing. (Expand the scope of information dissemination) Phase IV: telegraph, telephone, radio. (Electric to enter the time) Fifth stage: the information age,
5、 with the exception of language information, there are data, images, text and so on. 1.1 The history of modern data communications Communication as a Telecommunications are from the 19th century, the beginning Year 30. Faraday discovered electromagnetic induction in 1831. Morse invented telegraph in
6、 1837. Maxwells electromagnetic theory in 1833. Bell invented the telephone in 1876. Marconi invented radio in 1895. Telecom has opened up in the new era. Tube invented in 1906 in order to simulate the development of communications.Sampling theorem of Nyquist criteria In 1928. Shannong theorem in 19
7、48. The invention of the 20th century, the 2 semiconductor 50, thereby the development of digital communications. During the 20th century, the invention of integrated circuits 60. Made during the 20th century, 40 the concept of geostationary satellites, but can not be achieved. During the 20th centu
8、ry, space technology 50. Implementation in 1963 first synchronized satellite communications. The invention of the 20th century, 60 laser, intended to be used for communications, was not successful. 70 The invention of the 20th century, optical fiber, optical fiber communications can be developed. 1.
9、2 Key figures Bell (1847-1922), English, job in London in 1868. In 1871 to work in Boston. In 1873, he was appointed professor at Boston University. In 1875, invented many Telegram Rd. In 1876, invented the telephone. Lot of patents have been life. Yes, a deaf wife. Marconi (1874-1937), Italian peop
10、le, in 1894, the pilot at his fathers estate. 1896, to London. In 1897, the company set up the radio reported. In 1899, the first time the British and French wireless communications. 1916, implementation of short-wave radio communications. 1929, set up a global wireless communications network. Kim w
11、on the Nobel Prize. Took part in the Fascist Party. 1.3 Classification of Communication Systems According to type of information: Telephone communication system, Cable television system ,Data communication systems. Modulation by sub: Baseband transmission,Modulation transfer. Characteristics of tran
12、smission signals in accordance with sub: Analog Communication System ,Digital communication system. Transmission means of communication system: Cable Communications,Twisted pair, coaxial cable and so on. And long-distance telephone communication. Modulation: SSB / FDM. Based on the PCM time division multiple coaxial digital base-band transmission technology. Will gradually replace the coaxial fiber. Microwave relay communications:Comparison of coaxial and easy to set up, low investment, short-cycle. Analog phone microwave communications mainly SSB / FM /
