电子与通信工程硕士专业英语part6.ppt

Lesson 3 电 信 Telecommunications  (UNIT 8 Passage B ) Intensive reading：1. 2. Lesson 3 电 信 Telecommunications  技术背景 Background： The four phases of the evolution of communications networks are shown in Table 8.1—— Lesson 3 电 信 Telecommunications  技术背景 Background： Lesson 3 电 信 Telecommunications  内容大纲 Outline： Hardware and Software · Hardware · Software Applications · Host-Terminal · File-Transfer · Computer-Network Lesson 3 电 信 Telecommunications  内容大纲 Outline： Telecommunication Services · Network · Information Retrieval · Electronic Mail · Bulletin Board Ongoing Developments preface Lesson 3 电 信 Telecommunications  Telecommunications are the transmission of words, sounds, images, or data in the form of electronic or electromagnetic signals or impulses. Transmission media include the telephone (using wire or optical cable), radio, television, microwave, and satellite. Data communication, the fastest growing field of telecommunication, is the process of transmitting data in digital form by wire or radio. 精读详解 Intensive reading： preface Lesson 3 电 信 Telecommunications  Digital data can be generated directly in a 1/0 binary code by a computer or can be produced from a voice or visual signal by a process called encoding. A data communications network is created by interconnecting a large number of information sources so that data can flow freely among them. The data may consist of a specific item of information, a group of such items, or computer instructions. Example include a news item, a bank transaction, a mailing address, a letter, a book, a mailing list, a bank statement, or a computer program. 精读详解 Intensive reading： preface Lesson 3 电 信