数字逻辑设计及应用教学课件：2和3章作业评讲.pptVIP

Chapter2

homework

2.4

321076543218

=2

=(321)(037)(130)(321)82.11decimal-42signed-magnitudewo’s-complementone’s-complement2.22

2.35001–010,011–100,101–110,111–000.2.36WhentheLSBchangesfrom0to1,there’snoproblem.WhentheLSBchangesfrom1to0,sodoesthenextbit(andpossiblyothers),guaranteeingaproblem.So,halftheboundariesarebad,atotalof2n-1forann-bitencodingdisc.

EXERCISE

SOLUTIONSChapter3

3.1The“probably”casesmaycausedamagetothegateifsustained.(a)0(b)0(c)1(d)probably0(e)undefined(f)probably0(g)1(h)probably1

3-11((A.B)+(C+D))’

3.12((A+B).(C.D))’

3.20Thefirstanswerforeachparameterbelowassumescommercialoperationandthatthedeviceisusedwiththemaximumallowable(TTL)load.Thenumberinparentheses,ifany,indicatesthevalueobtainedunderalesserbutspecified(CMOS)load.VOHmin3.84V(4.4V)VIHmin3.15VVILmax1.35VVOLmax0.33V(0.1V)IImax1mAIOLmax4mA(20mA)IOHmax-4mA(-20mA)

3.23Currentispositiveifitflowsintoanode.Therefore,anoutputwithnegativecurrentissourcingcurrent.

3-56

4.12Eachproducttermofacanonicalsumhasnliterals,regardlessofwhetherornotthecanonicalsumhappenstobeaminimalsum.However,ifthecanonicalsumisaminimalsum,therecanbenootherminimalsum.Anotherminimalsumwouldhavetohavethesamenumberofproductterms,eachwithnliterals.Butsincenliteralproductterms(minterms)correspondexactlytothe1softhelogicfunction,suchaminimalsumwouldcoveradifferentsetof1sandthereforecouldnotbethesamelogicfunction.

4.34