海南大学电子通信 数学电子技术期末考试试题AWord格式文档下载.docx

海南大学电子通信 数学电子技术期末考试试题AWord格式文档下载.docx

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（PaperA）

（ElectronicInformation

Specialty&

TelecommunicationSpecialty）

I. 

Performthefollowingnumbersystemconversions:

（12points）

（1）101110.0100112 

=?

8 

16

（2）60910 

16=?

2

（3）FEA16 

10 

8

II. 

ComputetheLOW-stateandHIGH-stateDCnoisemarginsforeachofthefollowingcasesofaTTLoutputdrivingaTTLcompatibleCMOSinput,orviseversa.（12points）:

1.74HCTdriving74AS;

2. 

74F 

driving74VHCT

III. 

ComputetheoverallfanoutforeachofthefollowingcasesofaTTL-compatibleCMOSoutputdrivingmultipleinputsinaTTLlogicfamily,orTTLoutputdrivingmultipleTTLinputs.（12points）

1.74HCTdriving74LS;

driving74S

IV. 

Findaminimalsun-of-productsexpressionforeachoffollowinglogicfunctions.（15points）

1. 

3. 

V. 

Pleasemakea4-to-16decoderbyDual2-to-4decoder74x139sonly.Thelogicsymbolof74x139isshowninfollowingfigure.（12points）

VI. 

Analysistheclockedsynchronousstatemachineinfollowingfigure.Writeexcitationequations,excitation/transitiontable,andstate/outputtable.（15points）

VII. 

Sketchtheoutputwaveformsofaclockedsynchronousstatemachinewithfollowingstructureandinputwaveforms.Assumethatinputandoutputriseandfalltimesarezero,andtheoutputsofflip-flopsatthebeginningtimeareall0s.（12points）

VIII. 

Pleasemakeamodulo-12counterusingmdulo-16counter74x163andothercombinationalcircuits.Thelogicsignalof74x163isshowninfollowingfigure.（Youcansketchthelogicdiagramdirectlyinfollowingfigure. 

10points）

Table1:

Table2:

Table3

Specialty）

Keys

（15points）

=56.238 

=2E.4C16

=26116=10011000012

=407410 

=77528

1.74HCTdriving74AS

Solution:

Accordingtotable1,table2andtable3,theSteady-Stateelectricalbehaviorsof74HCTare:

VOHmin=3.84V, 

VOLmax=0.33V,

theSteady-Stateelectricalbehaviorsof74ASare:

VIHmin=2.0V, 

VILmax=0.8V,

The 

Low-stateDCnoisemarginis:

TheHigh-stateDCnoisemarginis:

Accordingtotable1,table2andtable3,theSteady-Stateelectricalbehaviorsof 

are:

VOHmin=2.7V, 

VOLmax=0.5V,

theSteady-Stateelectricalbehaviorsof74VHCTare:

1.74HCTdriving74LS

IOH=-4.0mA 

IOL=4.0mA

theSteady-Stateelectricalbehaviorsof74LSare:

IIH=20μA 

IIL=-0.4mA

ThefanoutsinLOWandHIGHstatesare:

Theoverallfanoutis10.

2.Accordingtotable1,table2andtable3,theSteady-Stateelectricalbehaviorsof 

IOH=-1000μA 

IOL=20mA

theSteady-Stateelectricalbehaviorsof74Sare:

IIH=50μA 

IIL=-2mA

Pleasemakea4-to-16decoderbyDual2-to-4decoder74x139sonly.Thelogicsignalof74x139isshowninfollowingfigure.（12points）

Analysistheclockedsynchronousstatemachineinfollowingfigure.Writeexcitationequations,excitation/transitiontable,andstate/outputtable.（15points）

Excitationequations;

Excitation/transitiontable:

Q1Q0

X

1

00

01

10

11

Q1*Q0*

State/outputtable:

S

A

B,0

B

C,0

D,0

C

A,0

D

A,1

S*,Z

VII.Sketchtheoutputofaclockedsynchronousstatemachinewithfollowingstructureandinputwaveforms.Assumethatinputandoutputriseandfalltimesarezero,andtheoutputsofflip-flopsatthebeginningtimeareall0s.（12points）

Pleasemakeamodulo-12counterusingmdulo-16counter74x163andothercombinationalcircuits.Thelogicsignalof74x139isshowninfollowingfigure. 

（7p