数字电路与逻辑设计英文教学ppt

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1、DigitalFundamentalsTenthEditionFloydChapter6©2008PearsonEducationQuiz2(20minutes)10111101001x1011ABCD0001111000011110RefertoKarnaughmap:WritethestandardSOP(SumofProduct)formfortheoutput(5points)WritethestandardPOS(productofSum)formfortheoutput(5points)Writethemini

2、mumSOPform.Drawthecircuit.(10points)WritetheminimumPOSform.Drawthecircuit(10points)Basicrulesofbinaryadditionareperformedbyahalfadder,whichhastwobinaryinputs(AandB)andtwobinaryoutputs(CarryoutandSum).SummaryHalf-AdderTheinputsandoutputscanbesummarizedonatruthtable

3、.ABSCoutThelogicsymbolandequivalentcircuitare:ABSCoutSSummaryFull-AdderBycontrast,afulladderhasthreebinaryinputs(A,B,andCarryin)andtwobinaryoutputs(CarryoutandSum).Thetruthtablesummarizestheoperation.Afull-addercanbeconstructedfromtwohalfaddersasshown:ABSCoutSABSC

4、outSABSumCoutCinABSCoutSCinSymbolSummaryFull-AdderABSCoutSABSCoutSExampleSolutionForthegiveninputs,determinetheintermediateandfinaloutputsofthefulladder.11010Thefirsthalf-adderhasinputsof1and0;thereforetheSum=1andtheCarryout=0.Thesecondhalf-adderhasinputsof1and1;t

5、hereforetheSum=0andtheCarryout=1.TheORgatehasinputsof1and0,thereforethefinalcarryout=1.101SumCoutSummaryFull-AdderABSCoutSABSCoutS11010101SumCoutNoticethattheresultfromthepreviousexamplecanbereaddirectlyonthetruthtableforafulladder.SummaryParallelAddersFulladdersa

6、recombinedintoparalleladdersthatcanaddbinarynumberswithmultiplebits.A4-bitadderisshown.ABSCoutCinABSCoutCinABSCoutCinABSCoutCinA1B1S1C0S2S3S4C1C2C3C4A2B2A3B3A4B4Theoutputcarry(C4)isnotreadyuntilitpropagatesthroughallofthefulladders.Thisiscalledripplecarry,delaying

7、theadditionprocess.SummaryParallelAddersThelogicsymbolfora4-bitparalleladderisshown.This4-bitadderincludesacarryin(labeled(C0)andaCarryout(labeledC4).The74LS283isanexample.Itfeatureslook-aheadcarry,whichaddslogictominimizetheoutputcarrydelay.Forthe74LS283,themaxim

8、umdelaytotheoutputcarryis17ns.BinarynumberABinarynumberBInputcarry4-bitsumOutputcarry123412341234C0C4SSummaryComparatorsThefunctionofacomparatoristocomp