數(shù)字儀表設(shè)計(jì)-數(shù)字復(fù)用表芯片新趨勢(shì)

數(shù)字儀表設(shè)計(jì)數(shù)字復(fù)用表芯片新趨勢(shì)一、前言:(DigitalMultimeters,DMM)Harris(Intersil)JRCMaximSamsungTelcom(Microchip)(AnalogtoDigitalConverter,ADC)A/DA/DDMM(Fluke)DMMDMM1-△(DualSlop)(Sigma-Delta)(DualSlop)(Hycon)HY12P65(Mixed-SignalMicrocontroller)DMM1-△二、可攜式電量儀表演進(jìn):(HandheldManualRangeDigitalMultimeters)ICL7106ICL7108TLC7135HI-7159ADMMDMM(HandheldAutoRangeDigitalMultimeters) TelcomTC818ASamsungKAD7001JRCNJU9210DMMDMM(MaximMAX133/MAX134)MCU(EpsonS1C62M20)MCUDMMHY12P65三、芯片新趨勢(shì)功能概述:DMM可規(guī)畫開關(guān)網(wǎng)絡(luò)DMMDMMuTiLTOHM'CAR'ITPM*|PBOHY12P65AnalogSwitchNetwork高解度EA模擬數(shù)字轉(zhuǎn)換器DMM A/DIIMPEMPP1-△50/60HZ(TrueRMS)RMS-DC(RootMeanSquare-DC)DMM !-△RMSInrushCurrent(PeakHold)DMMDMM優(yōu)點(diǎn).缶夬點(diǎn)Q平均值電路F電路藺單、成本低口行只有在測(cè)量正旋波之電量信號(hào)是正確，而在量測(cè)非正旋波即圖波峰因子('CrestFactor;-C-.F.)；波彤時(shí)，波峰f直比方均根值還大很多，量測(cè)讀值比實(shí)際方均根值還小，而會(huì)誤導(dǎo)使用者；造1^^電^擊1事故口方均根電路小精確度較局、可測(cè)量非正旋波電量信號(hào).由平均晌應(yīng)電路測(cè)量各種波形誤差可得知平均值電路和均方根電路的誤差.通常有均方根轉(zhuǎn)直流的模擬集成電路組件口卡 「使用均方根轉(zhuǎn)換專用組件抑：AnalogDevices的ADX4孤AD7冰AD637或是LinearTechnologyCjorpuaticm的LTC.ID用系列＞產(chǎn)品jof.本1局D數(shù)位方均根小將取樣之藪值經(jīng)過平方、平均、開根號(hào)計(jì)算，可精確量測(cè)到交流方均根值，并從取樣之?dāng)?shù)值得知信號(hào)之峰對(duì)峰值,口」量測(cè)較大CF的信號(hào)口甚至進(jìn)行信號(hào)分析.卡需要取樣速度快模擬數(shù)字轉(zhuǎn)換器；及搭配運(yùn)算能力隹之單赤片或馥字信號(hào)處理器，產(chǎn)品成本高口平(AnalogDevices.)各種波形?在波峰IV振幅。波峰因子*1實(shí)際方均根平均口向應(yīng)電路讀值叫平均響應(yīng)電路讀值誤差非失真正底波爐1414^0.7070.707V^加爐對(duì)稱方波爐1.00^l.QDVP1.11V-' 」+11.0%^非失真三角波爐1.73^0.577： 口.555VW底巔高斯噪聲夕3爐口:我V-p口.295%-11.4%^脈波*工作周期5吸產(chǎn)工作周期10%^1"0.5V+J0,t-W口.273V爐0.011V卡34軟-89%^&CR失真正弦波工作周期50.%^工作周期45%產(chǎn)，：4.7卡口4.95V+J0:712口.3'54%0.1504海-30%^*1：波峰因子①t■即Factor,:C.F.)^*2平均響應(yīng)電路以正弦波信號(hào)校正成方均根該值cLowPassFilter(LowPassFilter)OSR(Over-SamplingRatio)(Fluke289UsersManual)PlIMPUT.21m2ll-nOUT?UTPlIMPUT.21m2ll-nOUT?UT小口訐LMI02C2iaOjiFLowPassActiveFilterfor10kHzcutoff(NationalSemiconductorApplicationNote31)PeakHold(PeakHold)DMM

inicoLL!102LowDriftPeakDetector(NationalSemiconductorI比IIIOUTPUT 20KQlOKn1N9HinicoLL!102LowDriftPeakDetector(NationalSemiconductorI比IIIOUTPUT 20KQlOKn1N9HIH『UT3ApplicationNote31)溫度傳感器(Thermocouple)(ResistanceTemperatureDetectors;RTD)(Thermistor)(Seebeckeffect)(Cold-JunctionCompensation)DMM

Compensation)DMM0PA115s.aiknThermocouple如皿與f ZeroAdj%博叫4,09BVR,0PA115s.aiknThermocouple如皿與f ZeroAdj%博叫4,09BVR,也。做上尋工4厘2.94KLJK-TypoTemperatureMeasurementCircuit.(TexasInstrumentsOPAx235Datasheet)標(biāo)準(zhǔn)串行接口HY12P65UART(Unive