Unit16 Computer control.doc

Unit 16 Computer control Key words and expressions potential n. 潜能，潜在的 converter n. 变换器 difference equation 差分方程 synchronize v. 同时发生 synonym n. 同义词 feasibility n. 可行性 polymerization n. 聚合，多学科团队（引申） diversity v. 使多样性 installation n. 装置 Ferranti Argus一种计算机型号 panel n. 仪器版 flexibility n. 弹性 interaction n. 互相作用 regulator n. 调整器 vendor n. 销售商，卖方 Notations and Translation Computer-controlled systems can be viewed as approximations[?.pr?ksimei??n,??.pr?ks?mei??n] of analog-control systems, but this is a poor approach because the full potential of computer control is not used. At best the results are only as good as those obtained with analog control. It is much better to master computer-controlled systems, so that the full potential of computer control can be used. There are also phenomena that occur in computer-controlled systems that have no correspondence in analog systems.① It is important for an engineer to understand this. Fig. 1 a computer-controlled system A computer-controlled system can be described schematically as in Fig.1. The output from the process y(t) is a continuous-time signal. The output is converted into digital form by the analog-to-digital (A-D) converter. The A-D converter can be included in the computer or regarded as a separate unit, according to one’s preference. The conversation is done at the sampling times, tk. conversation (指通信) The computer interprets the converted signal,{y(tk)}, as a sequence of numbers, processes the measurements using an algorithm, and gives a new sequence of numbers, {u(tk)}. This sequence is converted to an analog signal by a digital-to-analog (D-A) converter. The events are synchronized[si?kr?naiz] 加载中... 此单词属于使用最频繁的10000个英文单词，是海词推荐用户应该学会的2星扩展词汇。 The digital computer operates sequentially in time and each operation takes some time. The D-A converter must, however, produce a continuous-time signal. This is normally done by keeping the control signal constant between the conversions. In this c