通信英语教程(ppt32)-电子电信(编辑修改稿)

通信英语教程(ppt32)-电子电信(编辑修改稿)内容摘要：

种重要方法。 1. 字符中的比特位并非全部用于表示数据。 All bits of a characters are not used to represent data. 2. 所有起始位都不被设定为信号电平。 No (None of) start bits are placed in the mark level. 3. 我们将字符的起始位设置成空号电平，而将字符的终止位设置成信号电平。 The start bit of a character is placed in the space level, and the stop bit the mark level. 4. 在计算机与其显示终端之间最为常见的串行接口是异步串行接口，而在电路交换机与其电话终端之间最为常见的串行接口是同步串行接口。 By far the most popular serial interface between a puter and its CRT terminal is the asynchronous serial interface, and between a circuit switch and its telephone terminal, the synchronous one. 5. 由发送器所送出的停止位总是被设置成信号电平。 Stop bit send by transmitters are always placed in the mark level. 6. 现在我们来考虑一个包含 8个信息比特加 4个控制比特的字符。 Now consider a character consisting of 8 information bit plus 4 control bits. 7. PCM是用以将模拟信号转换成数字信号的一种重要方法。 PCM is a important method used to convert an analog signal into a digital one. UNIT 3 形容词短语作后置定语： • a form suitable for transmission over these facilities. 常见的有： suitable for  , similar to  , capable of  , different from  , available to  , able to (do  ), necessary to (do  ), • a LSI chips available to the design engineer • motion parallel to the earth’s surface • a quantity greater than any number • something as small as a worm 插入语 插入语与其他部分没有直接语法关系，一般有逗号隔开，但也可以没有。 插入语位置不定，位于句首或主语之后较为常见。 •Even worse, a preface may resemble an advertisement for the text. •Wellgrounded students can absorb Chapters 4 and 5 in say three weeks. •What, you may wonder, does 54/74 stand for? •The author concentrated on what he thought he could do best. 编者主要集中在他认为他能写得最好的那些内容上。 •We could apply these two vectors, which it will be noticed are in polar form, to any work characteristic. 我们可以把这两种矢量应用于任何网络特性，而读者会注意到，这两种矢量均为极坐标形式。 插入语主要起承上启下的作用或表示作者的态度。 •Conversely, substances of small resistivity are good conductors. •This device consists in fact of five parts. •Who made the first generator in the world, then? •An increase in temperature, though, tends to make a gas expand. •Roughly speaking, microwaves are radio waves whose wavelength is less than 30 cm. •Velocity, we have noted before, is a vector quantity. •A few kiloohms will, I believe, be enough. 常用的插入语有： 一般来说， general。