光纤通信系统

光纤通信系统(中文7000字,英文4300字)
一般的通信系统由下列部分组成：
(1) 信息源。它产生消息可以是写成的或口说的文字，或是某种形式的数据。
(2) 发信机。发信机把消息转变为信号，信号形式要适合在通信信道中传送。
(3) 通信信道。通信信道是用于从发信机传送信号到接收机的媒质。信道可以无电链路或者是直接的有线连接。
(4) 收机。接收机可以看作与发信机相反的东西。它把接收到信号变回成消息，并把消息传给终端，这个终端可以是一台扬声器、电传打字机、或一个计算机数据库。
串行信号的生成

Optical Fiber Communications
    Communication may be broadly defined as the transfer of information from one point to another .When the information is to be conveyed over any distance a communication system is usually required .Within a communication system the information transfer is frequently achieved by superimposing or modulating the information on to an electromagnetic wave which acts as a carrier for the information signal .This modulated carrier is then transmitted to the required destination where it is received and the original information signal is obtained by demodulation .Sophisticated techniques have been developed for this process by using electromagnetic carrier waves operating at radio requites as well as microwave and millimeter wave frequencies.