一种测量共模抑制比的方法

©1994-2009ChinaAcademicJournalElectronicPublishingHouse.Allrightsreserved.*:2000-03-10:,,(1971),.213Vol.21No.320008JournalofLinglingTeachers’CollegeAug.20001(,425006),.,,,,[]O472[]A[]1008-1720(2000)03-0046-02AMETHODOFMEASURINGCMRRCHENXu-ri(DepartmentofPhysics,LinglingTeacher’sCollege,HunanYouzhou,CHINA,425006)AbstractThispaperanalysesthecommonwayofmeasuringCMRR,andproposesasimpleandhighlysophisticatedmethodofmeasuringCMRRofOperationalAmplifierCircuitKeywordsOperationalAmplifierCircuit,CMRR,CommonModeSignal,DifferentialSignal,VoltageGainCMRR,,CMRR,CMRRCMRR=AvdAvc,:CMRR(dB)=201gAvdAvcAvd,Avc.,,:1..2..:,,,.,,,.[1]:CMRR(dB)=20lgAvdAvc=20lgR2R1ViV0,,[2],,CMRRR=1+Avd4;CMRR:CMRR=CMRR1+CMRRCMRRR,A=100,=1%,CMRR=104CMRR=200,80%.CMRR80dB,10%,0.025%,,,,CMRR,,CMRR[3].,.2:©1994-2009ChinaAcademicJournalElectronicPublishingHouse.Allrightsreserved.(:)S,R2,R4,-+3;S,R2,R4,+-,4:,,V01,V02.CMRR(dB)=20lgR2R12VicV01+V02,.35:5,:6V1=Vic-Vi2(1)V2=Vic+Vi2(2)6,6R1R2,:Vi-R4R3+R4V2R1=R4R3+R4V2-V01R2:v01=(1+R2R1)R4R3+R4V2-R2R1V1(1),(2):v01=(1+R2R1)R4R3+R4-R2R1Vic+(1+R2R1)R4R3+R4+R2R1Vi2(3):R1=R3,R2=R4.(3)0,CMRR.4,:v02=(1+R4R3)R2R1+R2-R4R3Vic+(1+R4R3)R2R1+R2+R4R3Vi2(4)(3)+(4):(1+R2R1)R4R3+R4-R2R1+(1+R4R3)R2R1+R2-R4R3=(R1R4-R2R3)2R1R3(R1+R2)(R3R4),1,(R1R4-R2R3)2R1R3(R1R2+R3R4),,.CMRR(dB)=20lgR2R12VicV01+V02,,.[1].[M].:.[2],.[M].:.1980.[3].[M].:,1997.