计算机英语专业外语第三版UNIT 7.docx

计算机英语专业外语第三版UNIT 7
UNIT 7 Computer Communications
Section A Telecommunications and Computers
Telecommunly involve point-to-point transmission. Point-to-multipoint telecommunications, often called broadcasts, provide the basis for commercial radio and television programming.


个人通信，如两个人之间的电话对话或传真信息，通常涉及点对点的传输。点对多点的电信传输，通常称为广播，为商业广播和电视节目的播送提供了基础。
Telecommunications begin with messages that are converted into electronic signals. The signals are then sent over a medium to a receiver, where they are decoded back into a form that the person receiving the message can understand. There are a variety of ways to create and decode signals, and many different ways to transmit signals.
电信以信息转换为电子信号为开端。然后，这些信号通过媒介发送到接收机，并在这里解码，恢复为接收信息的人能够理解的形式。有各种方法可以产生并解译信号，也有许多不同的方法传输信号。
Devices such as the telegraph and telephone relay messages by creating modulated electrical impulses, or impulses that change in a systematic way. These impulses are then sent by wires, radio waves, or other media to a receiver that decodes the modulation.


电报机与电话机等设备，通过产生调制电脉冲或以系统化方式变化的脉冲，来传递信息。接下来，这些脉冲通过导线、无线电波或其他媒介发送给接收机，并由其进行解调。
UNIT 7 Computer Communications
Section A Telecommunications and Computers
Telecommunications al