科技英语4低通滤波器原文与翻译

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1、WordsandExpressionsintegratorn.积分器amplituden.幅值slopen斜率denominatorn.分母impedancen阻抗inductorn.电感capacitorn电容cascaden.串联passbandn通带ringingn.振铃dampingn.阻尼，衰减conjugateadj.共轭的stagev.成为low-passfilters低通滤波器buildingblock模块linearramp线性斜坡log/logcoordinates对数/对数坐标Bodeplot伯德图transfer

2、function传递函数complex-frequencyvariable复变量complexfrequencyplane复平面realcomponent实部frequencyresponse频率响应complexfunction复变函数Laplacetransform拉普拉斯变换realpart实部imaginarypart虚部angularfrequency角频率frequencyresponse频率响应transientresponse瞬态响应decaying-exponentialresponse衰减指数响应stepfuncti

3、oninput阶跃（函数）输入timeconstant时间常数first-orderfilters一阶滤波器second-orderlow-passfilters二阶低通滤波器passivecircuit无源电路activecircuit有源电路characteristicfrequency特征频率qualityfactorn.品质因子，品质因数circularpath圆弧路径complexconjugatepairs共轭复数对switched-capacitor开关电容negative-realhalfofthecomplexplan

4、e复平面负半平面Unit4Low-passFiltersFirst-OrderFiltersAnintegrator(Figure2.la)isthesimplestfiltermathematically,anditformsthebuildingblockformostmodernintegratedfilters.Considerwhatweknowintuitivelyaboutanintegrator.IfyouapplyaDCsignalattheinput(i.e.,zerofrequency),theoutputwill

5、describealinearrampthatgrowsinamplitudeuntillimitedbythepowersupplies.Ignoringthatlimitation,theresponseofanintegratoratzerofrequencyisinfinite,whichmeansthatithasapoleatzerofrequency.(Apoleexistsatanyfrequencyforwhichthetransferfunction'svaluebecomesinfinite.)（为什么为极点，为什

6、么低通？）Figure2.laAsimpleRCintegratorWealsoknowthattheintegrator'sgaindiminisheswithincreasingfrequencyandthatathighfrequenciestheoutputvoltagebecomesvirtuallyzero.Gainisinverselyproportionaltofrequency,soithasaslopeof-1whenplottedonlog/logcoordinates(i.e.,-20dB/decadeonaBo

7、deplot,Figure2.1b).Figure2.1bABodeplotofasimpleintegratorYoucaneasilyderivethetransferfunctionasWheresisthecomplex-frequencyvariableandis1/RC.Ifwethinkofsasfrequency,thisformulaconfirmstheintuitivefeelingthatgainisinverselyproportionaltofrequency.Thenextmostcomplexfilter

8、isthesimplelow-passRCtype(Figure2.2a).Itscharacteristic(transferfunction)isWhen,thefunctionreducesto,i.