NA及TDR教育训练资料.docx
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NA及TDR教育训练资料.docx
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NA及TDR教育训练资料
NA及TDR教育训练资料
Excellentscienceandtechnology,highfrequencymeasurement,education,training
Themeofeducationandtraining
Basicconceptsofsignals
Meaningofparameters
Networkanalyzer(NA)profile
Timedomainreflectometry(TDR)Introduction
.
AbriefintroductiontothemeasurementmethodsofNA/andTDR
.
ComparisonofNAandTDR
GhiatekTechnologies
GoodYePolytronTechnologiesInc
Firstpage
Basicmodeofsignaltransmission:
1,Single,end(singleended):
signal+groundwire
+
+
Analog(sinusoidal):
Gdigital(FangBo):
G
2,Common,mode(common/samemode):
signal+signal(boththesame)
+
Analog(sinusoidal):
+
Digital(FangBo):
+
+
GG
3,Differential,mode(differential/differential):
positivesignal
+negativesignals(opposite)
+
Analog(sinusoidal):
Digital(FangBo):
VG
VG
-
-
GhiatekTechnologies
GoodYe,PolytronTechnologiesInc,secondpages
Basicmodeofsignalreception:
1,Single,end(singleended)reception:
signalvoltage
=signallinevoltagegroundvoltage
S
Singleendedreceiver
Signal
=S-G=S(G=0)
G
Singleendedtransmission
2,Common,mode(samemode)reception:
signalvoltage=two,linevoltageplus/2-groundvoltage
S1
Signal
=(S1+S2)/2-G=S
Samemodereception
S2
(S1=S2=S,G=0)
G
Samemodetransmission
3,Differential,mode(differential)receive:
signalvoltage=two,signallinevoltagesubtraction
S1
VG
S2
Differentialreception
Signal
=S1-S2=S
(S1=,S/2,S2=,-S/2,VG=0)
Differentialtransmission
GhiatekTechnologies
GoodYe,PolytronTechnologiesInc,thirdpages
Basicmodeofsignalreception:
1,Singleend(singleended)transmission,differentialmodereceivingresults?
?
S
G
Differentialreceivesignal
And
Signal
=?
?
?
Singleendedtransmission
2,Commonmode(commonmode)transmission,differentialmodereceivingresults?
?
S1
S2
Differentialreception
Signal
=?
?
?
G
Samemodetransmission
3,Differentialmode(differential)transmissionmodewithareceivingresults?
?
S1
VG
Samemodereception
Signal
=?
?
?
S2
Differentialtransmission
GhiatekTechnologies
GoodYe,PolytronTechnologiesInc,fourthpages
Characteristicsofbasicsignals:
1,Single,end(singleended)
):
Advantages:
simplesignalprocessing,lowwirecost
ExceptforCOAXIAL,highercost)
Disadvantages:
higherworkingvoltage,highfrequencyinterference(exceptforCOAXIAL,mostundisturbed)
2,Common,mode(CO/samemode):
Essentially,analogtransmissionisusedtosimulatenoiseorasameasurementofwirebalancecharacteristics,
Thereisnoneedtotransmitsignalsingeneral
3,Differential,mode(differential/differential):
Advantages:
lowvoltage,noisecancellationfunction(highfrequencyperformance/priceratio,optimum)
Disadvantages:
signalprocessingcostsarehigher
GhiatekTechnologies
GoodYe,PolytronTechnologiesInc,fifthpages
Highfrequencycharacteristicsofthebasiclineterminationstructure:
Open
1,Open(open/circuit):
Features:
signaltotalreflection,withthesamephase
2,Short(shortcircuit):
Characteristic:
signaltotalreflection,butopposite
Short
MatchingLoad
3,Matching,Load(matchingload):
Characteristics:
signalcompleteabsorption(transmission)withoutreflection
4,Unmatching(incompletematch):
Characteristics:
thesignalportionabsorbs(transmits),partiallyreflects
UnmatchingLoad
GhiatekTechnologies
GoodYe,PolytronTechnologiesInc,sixthpages
Highfrequencycharacteristicsofthebasiclineterminationstructure:
V
Open.
I=0
IiV
Features:
signaltotalreflection,withthesamephase
V
V
I
V
IrVR
1,Open(open/circuit):
2,Short(shortcircuit):
Characteristic:
signaltotalreflection,butopposite
R,V,I,V,rI,iI,R,I,iI
VVV
=T==-0
IIiV
V
IrV,
I,V,R,V,R,V,iV
VV
-==+0
V
V
V
V
V
Short
V
V
R
V
GhiatekTechnologies
GoodYe,PolytronTechnologiesInc,seventhpages
Overviewofhighfrequencytransmissionofbasiclines
Theactuallinecannotbecompletelymatched,sothesignalistransmittedovertheline
Aseriesofpenetrating(absorption)andreflectedresults
receivingend
Transmittingend
defect
GhiatekTechnologies
GoodYe,PolytronTechnologiesInc,eighthpages
Excellentscienceandtechnology,highfrequencymeasurement,education,training
Themeofeducationandtraining
Basicconceptsofsignals
Meaningofparameters
Networkanalyzer(NA)profile
Timedomainreflectometry(TDR)Introduction
.
AbriefintroductiontothemeasurementmethodsofNA/andTDR
.
ComparisonofNAandTDR
GhiatekTechnologies
GoodYePolytronTechnologiesInc
Ninthpage
Meaningofparameter
Characteristicimpedance
CharacteristicImpedance,
Z)
Thetransmissionlineisaffectedbyitsstructure,andwhenahighfrequencysignalistransmitted,thecharacteristicofcurrentandvoltageineachpointofthewireishigherthanthatofthetransmissionline.
Theformulaisasfollows:
'Lp2jR+PhiPhiV
=R+jwxf>>0),verysmall,'R'(ifG'CofjG
==0Z
=
PfC2+phiI
Dependingonthetypeofsignaltransmitted,theimpedancemeasuredcanbedividedintothefollowingthree
:
Singleendedimpedance
Zse(Single,Ended)
Twodifferentialimpedance
Zdiff(Differential,Mode)
Three,samemodeimpedance
Zcom(Common,Mode)
Ingeneral,theportoftheinstrumentissingleended
Theimpedanceof50ismostcommon.IfyouwanttomeasurewithNA
Differentialsignal
"When,
Needtogothrough
Bulanconversionwill
NA
Singleendedsignal
"Convertstodifferentialsignals.
TDR
Singleendedsignal
Turn...Into
Differentialsignal
"Or"samemodesignal",justsettheinstrumentport.
Lf
GhiatekTechnologies
GoodYe,PolytronTechnologiesInc,tenthpages
Meaningofparameter
Attenuation/insertionloss
Alpha,
Attenuation/InsertionLoss)
Referstotheoutputvoltage(Vout)andtheincidentvoltage(Vin),comparedtotheremainingsignalloss?
.
UsuallymeasuredbyNA,whichcanbedirectlymeasuredbytheinstrumentandexpressedintheformofdB
Theformulaisasfollows:
Alpha
=10log(Pout/Pin)=20log(Vout/,Vin)
IftheATTvalueiscloserto
0,thelesssignallossoccurs.Otherwise,theATTvalue
Themorenegative(smaller)is,themoreseriousthesignallossis.
Vin
Vout
GhiatekTechnologies
GoodYe,PolytronTechnologiesInc,eleventhpages
Meaningofparameter
Propagationdelaytime
Delay)
Referstothesignalinthetransmissionline,fromtheinputnumbertothereceivingend
Thetimerequiredcanbedividedaccordingtothesignaltype:
First,singleendeddelay(Single,Ended,Delay)
Two,differentialdelay(Differential,Mode,Delay)
Three,samemodedelay(CommonModeDelay)
Delay
GhiatekTechnologies
GoodYe,PolytronTechnologiesInc,Twelfthpages
Meaningofparameter
Propagationdelaytimedifference
DelaySkew)
Referstothetimedifferencebetweenthesignalandthereceiveratdifferentsignallines,thatis,Delay
Difference,thecommonDelaycanbedividedintotwokinds:
Differentialpairinternaldelay(Intra-pairSkew)referstotheinputdifferentialsignal,
DifferencebetweentheSingle-endDelayoftwowiresinthesamepairoflines(subtraction).
Two,differencebetweenthedelaydifference(Inter-pair,Skew),referstothedifferencebetweentheline
DifferentialDelaydifference(subtraction).
IfthevalueoftheDelaySkewislonger,thesmallerthetimedifferenceofthesignaltransmissionis,the
Thetransmissioncharacteristicsareconsistent.
Conversely,thelargertheDelaySkewvalue,thegreaterthetimedifferenceinthesignaltransmission
Thetransmissionpropertiesofwoodareinconsistent.
GhiatekTechnologies
GoodYe,PolytronTechnologiesInc,thirteenthpages
Meaningofparameter
(difference)delaydifferencebetweentwosystems(
Inter-pairSkew)yes
Oforbetweenlines
DifferentialDelaysubtraction.
-ismorethan2timesthemeasurecalculated
InterpairSkew
GhiatekTechnologies
GoodYe,PolytronTechnologiesInc,fourteenthpages
Meaningofparameter
Differentialtointernaldelaydifference
Intra-pair,Skew)meansthesame
Oftwowiresinaline
Single-endDelaysubtraction.
-in
SettheDifferentialsignalonTDR,onetimestraight
Youcanpickitup
Skew,=0,Intra,pair,Skew
GhiatekTechnologies
GoodYe,PolytronTechnologiesInc,Fifteenthpages
Meaningofparameter
Crosstalk
Xtalk,Cross,talk)
Electromagneticnoiseoftwolinesthatinterferewitheachothergenerallyincreaseswithincreasingfrequency.
Themeasurementscanbemade
NAor
TDRtomeasure,theformulaisasfollows:
Xtalk=10,log(Pout/Pin)=20,log(Vout/,Vin)in,dB,by,NA
Xtalk=Vout/Vinin%byTDR
IftheXtalkvalueapproachesthe0dB(ornear100%),thenoisedisturbanceismoreserious.
Conversely,theXtalkdBvalueisnegative(ornear)
0%)thereislessnoiseinterference.
GhiatekTechnologies
GoodYe,PolytronTechnologiesInc,sixteenthpages
Meaningofparameter
GhiatekTechnologies
GoodYePolytronTechnologiesInc
Crosstalkcanbedividedintotwomajorcategories:
Nearendcrosstalk
farendcrosstalk
Crosstalk(Xtalk,Cross,talk)
Vin
Vnear
NEXT=20,log(Vnear/,Vin),in,dB,or,Vnear/,Vin,in,%
FEXT=20,log(Vfar/,Vin),in,dB,or,Vfar/,Vinin,%
Vfar
Seventeenthpage
Meaningofparameter
Declineinrisetime
Tr,Risetime,degradation)
Whenthesignalpassesthroughtheobjecttobemeasured,thewaveformriseslonger,andthelongeritrises,thesignal
Apartialdeclineofhigherfrequency
Themoreserious,thesmallertherangeofbandwidthavailable.
0.35=risetimerecession(NS)*bandwidth(GHz)
80%
20%
DUT
Tr_sys
Tr_mea
Tr_sys:
systemrisetime(includingconnectingwiresandfixtures)
Tr_mea:
finalmeasurementtimeofrise
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