Lesson 5 Low-pass Filters.ppt

《电子信息工程专业英语教程》 Unit 2 Electronic Circuits Lesson 5 Low-pass Filters 《电子信息工程专业英语教程》任治刚 主编 电子工业出版社 Lesson 5 Low-pass Filters Terminology DC: Direct Current 直流电 AC: Alternating Current　交流电 Laplace transform 拉普拉斯变换 Bode plot 伯德图 transfer function 转移函数 complex plane 复平面 decaying-exponential response 衰减指数响应 quality factor 品质因数　 Vocabulary variable, transient , order , response, formula, function , factor, origin Structure Reading/writing techniques A quantity that can assume any of a given set of values. Any factor or condition which can be measured, altered, or controlled (e.g. , temperature, pressure, flow, liquid level, humidity, weight, chemical composition, color, etc.). A language object that may take different values, one at a time. Note: The values of a variable are usually restricted to a certain data type. In programming, a character or group of characters that refers to a value and, in the execution of a computer program, corresponds to an address. You can easily derive the transfer function as where s is the complex-frequency variable σ+ jωand ω0 is 1/RC. 传输函数很容易推导出来（公式略）；其中，s是复频率变量σ + jω，而ω0等于1/RC。 variable weather 变化无常的天气 a man of variable character 反复无常的人 variable standards 变化的标准 variable gears 变速齿轮 variable capital 可变资本 complex variable 复变数 n-dimensional random variable n 维随机变量 normal random variable 正态随机变量 real variable 实变量 scalar variable 标量变量 time variable 时间变量 Passing with time; transitory: 短暂的 Remaining in a place only a brief time: 短期的，临时的 Decaying with time, especially as a simple exponential function of time. 瞬变的 A transient phenomenon or property, especially a transient electric current. 瞬变现象 When analyzing transient response using Laplace transforms, we use sL and 1/sC for the impedance of these elements. 在使用拉普拉斯变换分析瞬态响应时，我们用sL和1/sC分别表示电感的阻抗和电容的阻抗。 While the complex frequencys imaginary part (j?) helps describe a response to AC signals, the real part (?) helps describe a circuits transient response. 复频率的虚部有助于描述电路对交流信号的