测控技术与仪器专业英语unit 6

Unit6SignalConditioningUnit6SignalConditioningUnit6SignalConditioningAmeasuringtransmitterconsistsoftwoparts:aprimaryelement(orsensor)andasignalconditioner.Theprimaryelementusessomecharacteristicofitsmaterialandconstructiontoconvertthevalueofameasuredvariableintoanelectrical,mechanical,orfluidicsignal.译为：一个测量传感器由两部分组成：一个基本元件（传感器）和一个信号调制器。基本元件利用其材质的特性和结构将被测量转化为电的、机械的或者流体的信号。Unit6SignalConditioningTheoutputoftheprimaryelementmaybeasmallvoltageoranelectricalresistance.Itmaybeaforce,adisplacement,apressure,orsomeotherphenomenon.Nomatterwhatformittakes,theprimaryelementoutputdependsonthevalueofthemeasuredvariable.译为：基本元件的输出可能是一个小的电压或电阻。也可能是一个力、一个位移、一个压力或其他一些现象。不论它采取何种形式，基本元件的输出依赖于测得量的数值。Unit6SignalConditioningTheoutputoftheprimaryelementisameasureofthevariableitissensing,butitisseldominaformsuitablefortransmissionandusebyothercomponentsinasystem.译为：基本元件的输出是对它测量的变量的度量。但是它很少采用一种便于传输或被系统中其他部分使用的形式。Unit6SignalConditioningUsually,asignalconditionerisrequiredtoconverttheprimaryelementoutputintoanelectrical(orpneumatic)signalsuitableforusebyacontrollerordisplaydevice.Asignalconditionerpreparesasignalforusebyanothercomponent.Theinputtoasignalconditionerisusuallytheoutputfromasensor(orprimaryelement).译为：通常，一个信号调制器被用来将基本元件的输出变换为一个便于被处理器或显示设备使用的电（或气）信号。一个信号调节器将信号准备好以备其他设备使用，信号调制器的输入通常是传感器的输出（或基本元件）。Unit6SignalConditioningThefull-scaleoutputsofmostsensors(passiveoractive)arerelativelysmallvoltages,currents,resistancesandcapacitances.Beforefurtheranalogordigitalprocessingcantakeplace,theseoutputsmustbescaledorconvertedtousefulranges.句中full-scale意为“满量程”，passivesensor意为“被动型传感器”，activesensor意为“主动型传感器”，scale在这里指“换算缩放，改变值的大小”。译为：绝大多数传感器（被动型或主动型）的满量程输出都是比较小的电压、电流、电阻和电容。在进行进一步模拟或数字信号处理之前，这些输出必须要换算缩放或转换到可用的范围。Unit6SignalConditioningThestandardtransmissionsignalsarea4to20mAelectriccurrentora3to15psipneumaticpressure.Forexample,athermocouple（热电偶）(T/C)isaprimaryelementthatconvertstemperatureintoasmallvoltage.Asignalconditionerconvertsthemillivoltoutputofthethermocoupleintoa4to20mAelectriccurrent.AT/Ctemperaturetransmitterincludesboththethermocoupleandthesignalconditioner.psi为压力的单位，poundspersquareinch，磅/平方英寸。pneumaticpressure意为“气压”.译为：标准的传输信号是一个4至20毫安电流或一个一个3至15磅/平方英寸气压。例如，热电偶是一种将温度转化为小电压的基本元件。一个信号调制器将热电偶的毫伏输出转化为4至20毫安的电流，一个热电偶温度变送器同时包含热电偶和信号调制器。Unit6SignalConditioningSignalconditioningcircuitsperformthenecessaryamplification,leveltranslation,impedancetransformation,linearizationandfiltering.Thecharacteristicsofanderrorinthesensoroutputdeterminethetypeofsignalconditioningcircuitsneeded.译为：信号处理电路实现必要的信号放大、电平变换、阻抗变换、线性化和滤波。传感器输出的特征及其误差决定需要哪种信号调制回路。Unit6SignalConditioningIfthesensoroutputisnotconditionedproperly,factorssuchassensitivity,voltageandcurrentlevels,linearity（线性度，线性）,impedances,gain,offset,drift,timeconstants,maximumelectricalratings（最大额定电功率）,strayimpedances（杂散阻抗，寄生阻抗）andotherimportantconsiderationscanimpacttheoverallperformanceofthesensor.Asaresult,theoverallsystemwillsuffer,particularlywhenhighresolution,precisionorverylowlevelmeasurementsareinvolved.译为：如果传感器的输出没有被正确的调制，诸如灵敏度、电压和电流电平、线性度、阻抗、增益、补偿、漂移、时间常数、最大额定电功率、寄生阻抗和其他重要的因素能够影响传感器的整体表现。其结果是整个系统将受到影响，特别是当涉及高清晰度，准确度或很差水平的测量时。Unit6SignalConditioningCaremustbetakenwhendesigningsignalgenerationandconditioningcircuitstoensurethatthesensoristheleastaccuratecomponentofthesystem.Ifsurroundingcircuitryaddsnoiseordegradesaccuracy,theaccuracyofthesensoroutputiscompromised.译为：设计信号发生器和调制回路时一定要警惕以保证传感器是系统中准确度最低的部件，如果周围回路有附加噪声或降低了准确度，传感器输出的准确度将受影响。Unit6SignalConditioningThefollowingaresomeofthetasksperformedbyasignalconditioner:以下是一个信号调制器执行的操作：（1）Isolationandimpedanceconversion;隔离和阻抗变换（2）Amplificationandanalog-to-analogconversion;放大和模-模转换（3）Noisereduction(filtering);降噪（滤波）（4）Linearization;线性化（5）Datasampling;数据采样（6）Digital-to-Analogconversion;数-模转换（7）Analog-to-Digitalconversion.模-数转换Unit6SignalConditioningVoltageoutputThreetypesofinputtopologiesexistforthesignalconditioningofvoltageoutputsensors:differential,single-endedandpseudo-differential.Thetypeofsignalconditioninginputistypicallymatchedtotheoutputstructureandprecisionrequirementsofthesensor.句中differential有“微分”和“差分”之意，这里指信号处理的方式，意为“差动”。译为：电压输出传感器的信号处理有3种输入拓扑方式：差动方式、单端方式和伪差分方式。信号调制输入的类型要符合特定的输出结构和传感器的准确性要求。Unit6SignalConditioningAdifferentialdevicerejectsinputsignalscommontothebalancedinputpair(+and-)whileacceptingthedifferencebetweentheinputsignals,specifiedastheCommon-ModeRejectionRatio(CMRR).Thedeviceisdesignedsothatthenoisecommontobothinputsisrejectedwhilethesignalofinterestisnot.句中balancedinput意为“对称输入”，Common-ModeRejectionRatio(CMRR)意为“共模抑制比”。译为：差动装置在接收两输入端口的差分信号时，抑制这两个对称输入端口（+和-）的共模输入信号，这称为共模抑制比CMRR。这个装置被这样设计两个输入共有的噪声被抑制而所需要的信号不被抑制。Unit6SignalConditioningMuchlikedigitaldifferentialinputsignalssuchasLVDS,theanalogsignalsmaybeinvertedtoadoubledynamicrangeasiscommonwithdifferentialoutputdevices.译为：和数字差分输入信号如低压差分信号很类似，模拟信号可以倒置成一个双重动态范围和差分输出设备的输出一样。Unit6SignalConditioningThistypeofinputtopology（拓扑，拓扑结构，布局，拓扑学）isusedwhenmaximumnoiserejectionisrequiredandthesensormeasurementisnottiedtoground,aswiththeWheatstonebridge（惠斯顿电桥）configuration.Fo