通信基础知识

英文翻译
通信基础知识(中文2700字,英文2000字)
通信系统
一般的通信系统由下列部分组成：
（a）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。
（b）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。
（c）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。信道可以是无线电链路或者是直接的有线连接。
（d）接收机。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。
所有通信信道的一个不好的特征是信号上都叠加了噪声。这种人们不希望存在的噪声会引起电话中声音失真，或者在电报报文或数据中出现的差错。

附录一：英文资料
Basic Knowledge of Communication
Communication System
A generalized communication system has the following components
(a)     In formation Source .This produces a message which may be written or spoken words,or some form of data.
(b)    Transmitter .The transmitter converts the message into a signal ,the form of which is sutiable for transmission over the communication channel.
(c)    Communication Channel .The communication channel is the medium used transmit the signal, from the transmitter to the receiver. The channel may be a radio link or a direct wire connection.
(d)    Receiver . The receiver can be thought of as the inverse of the transmitter .It changes the received signal back into a message and passes the message on to its destination which may be a loudspeaker , teleprinter or computer data bank.
 An unfortunate characteristic of all communication channels is that noise is added to the signal. This unwanted noise may cause distortions of sound in a telephone , or errors in a telegraph message or data.