1.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. 在通信系统中,信息传递通常是通过把信息叠加,调制,加到一个充当信息信号传输载体的电磁波上来完成的. 

2.In electrical communications the information source provides an electrical signal,usually derived from a message signal which is not electrical(e.g.sound),to a transmitter comprising electrical and electronic components which converts the signal into a suitable form for propagation over the transmission medium. 在电通信中,信息源提供一个电信号到传输器上,这个电信号通常来源于一个非电的消息信号例如声音.传输器由电器件和电子器件构成.它把信号转化为一个合适的形式,从而在传输媒介上传播.

3.However,at this stage it is instructive to consider the advantages provided by lightwave communication via optical fibers in comparison with other forms of line and radio communication which have brought about the introduction of such systems in many areas throughout the world. 然而,相比于其它在全世界很多地区引进这样的系统的有线及无线电通信方式来说,重视由光纤实现的光波通信的优势是很有意义的. (我觉得这句我翻得很不好...)

5.It has been proposed that feedback from the output device be used to permit one simple output program to drive terminals with different characteristics. 有人提出外部设备的反馈应该用来允许一个简单的外部程序驱动不同特点的终端．

6. The success of mobile systems across the world is a sign that communication is moving towards a more personalized,convenient system. 移动系统在世界范围内的成功标志着通信正向一个更个体化，更方便的系统发展．

7. Imagine a network that would break down the walls of classrooms,letting teachers,students,and staff directly access computer-based resources and other communications facilities. 设想一下，一个网络将打破教室的高墙，使教师，学生，职员直接与电脑基础资源和其它交流设备接触．

8.Other services might include call forwarding,call waiting,and special telephone ring signals,all tailored dynamically by the user depending upon the telephone number of the calling party． 其它服务包括呼叫转移，呼叫等待和特殊电话铃信号，它们都由用户灵活制定，取决于参与呼叫的电话号码． tailored dynamically这里．．．

9.Interest in multimedia is currently pervasive--entertainment and educational groups are exploring new applications,and the computer,telecommunications,and consumer electronics industries are actively developing underlying technology. 现今，多媒体越来越引起人们的兴趣－－－娱乐和教育群体正在探索它新的应用，计算机，电信和消费者电子工业正积极地开发它潜在的技术． consumer electronics industries 是否该译成：面向消费者的电子工业？

10.Computational image processing can be defined as the operation of mathematical functions on numeric representations of pictorial scenes. 计算机图象处理过程可被定义为数学功能在图象的数字描述上的应用．

11.This examination would take up over 67 Mbytes and it needs considerable computing power to do quite simple things with the data in any acceptable time scale. 这个试验将占据６７兆字节，并且他需要相当大的计算机功能在可接受的的时间尺度内来完成这些与数据有关的非常简单的事情．

不好意思,多了点,但这个对我很重要,我想要做到更好一点.拜托拜托!!

米人理我,555...

第三句我是这样翻译的：不过，在现阶段，相比于那些给全世界很多地方带来有线或无线通信方式这样的系统来说，重视由光纤实现的光波通信的优势是很有意义的.4.premise有前提的意思啊，应该是指你所说的那意思。第八个好像以前看过么，all后面的好像应该这么翻译：这一切都由依赖于呼叫方电话号码的用户灵活调节使之适应。9.consumer electronics industries 就直接翻译成“消费电子产业”好了。 电信方面的专业术语我也不是很懂啊，翻译的应该不错了。