Jitter Jitter ExperimentExperiment

Final presentationFinal presentation

Performed byPerformed by

Greenberg OlegGreenberg Oleg

Hahamovich EvgenyHahamovich Evgeny

Spring 2008

Supervised by

Mony Orbah

ObjectiveObjective

Creating an experiment environment, which will Creating an experiment environment, which will include theoretical introduction and practical include theoretical introduction and practical exposure to the jitter subject, allowing the exposure to the jitter subject, allowing the student to investigate and get familiar with Jitter student to investigate and get familiar with Jitter types, components and sourcestypes, components and sources

Motivation for Jitter AnalysisMotivation for Jitter Analysis

Uniform RequirementsUniform Requirements

Clock Statistic AnalysisClock Statistic Analysis

Short Time Measurements ExtrapolationShort Time Measurements Extrapolation

Determining Jitter ComponentsDetermining Jitter Components

Experiment EnvironmentExperiment Environment

Tabor Arbitrary Waveform Generetor 2571aMaximum frequency 100 MHzAbility to create different Modulation types

Agilent Oscilloscope MS08104ABandwidth 1 GHzSample Rate 4 GS/s

“EZJIT” Package

Jitter created by FM

“EZJIT Plus” options were implemented using DSO80204B Oscilloscope model

Experiment OverviewExperiment Overview IntroductionIntroduction Part A – Jitter basicsPart A – Jitter basics

• Eye diagramEye diagram• Introduction to hIntroduction to histogramistogram• Analyzing relation between Jitter typesAnalyzing relation between Jitter types• Mathematical connection between Jitter typesMathematical connection between Jitter types

Part B – Jitter separation methodologyPart B – Jitter separation methodology• Dual-Dirac model definitionDual-Dirac model definition• Tail fit separation methodTail fit separation method• Fourier transform separation methodFourier transform separation method

Part C – Jitter statistic analysisPart C – Jitter statistic analysis• Eye closure using bathtub curveEye closure using bathtub curve• Margins measurementMargins measurement• RJ-DJ identificationRJ-DJ identification

AppendixesAppendixes

Part A Part A

Jitter basicsJitter basics

Eye DiagramEye DiagramObjective Objective

Introduction to eye diagramIntroduction to eye diagram Noise influence on eye opening (sampling margins)Noise influence on eye opening (sampling margins)

RealizationRealization Creating phase noise using FM modulationCreating phase noise using FM modulation Analyzing eye diagram for a clean signal vs. “noisy” (modulated) signalAnalyzing eye diagram for a clean signal vs. “noisy” (modulated) signal

Clean (un-modulated) signalClean (un-modulated) signal FM modulated signalFM modulated signal

HistogramHistogramObjective Objective

Introduction to HistogramIntroduction to Histogram Characterizing Jitter using HistogramCharacterizing Jitter using Histogram

RealizationRealization Histogram for voltage levelHistogram for voltage level Histogram for Jitter measurementHistogram for Jitter measurement

Sin wave histogramSin wave histogram TIE histogram for FM TIE histogram for FM modulation by a sin wavemodulation by a sin wave

Jitter Measurement TypesJitter Measurement Types

Objective Objective Visualization of differential / integration relation between jitter measurement typesVisualization of differential / integration relation between jitter measurement types Calculating ratio of Std Dev between different jitter measurement typesCalculating ratio of Std Dev between different jitter measurement types

RealizationRealization Using FM modulation analyzing TIE, C2C and periodic Jitter trendsUsing FM modulation analyzing TIE, C2C and periodic Jitter trends Increasing RJ by lowering the amplitude and the slope of the waveIncreasing RJ by lowering the amplitude and the slope of the wave

Jitter Measurement TypesJitter Measurement Types

2 2 2Period b a Period

2a b Period

2 2 2 2C2C c b b a c b a 2

2a b c 2

T = t - t +

and for: t ,t ~ N(0, ) 2

T = (t - t ) - (t - t ) =t - 2t +t +4 +

and for: t ,t , t ~ N(0, ) 6

a b

a b c

t t

C C t t t

C C

Std Dev Measurement ResultsStd Dev Measurement Results

2

2

899.511.73 3 0.11%

519.67

519.671.38 2 2.4%

376.68

899.512.39 6 2.5%

376.68

C C

Period

Period

TIE

C C

TIE

Difference

Difference

DIfference

TIE jitter trendTIE jitter trend

Trend Measurement ResultsTrend Measurement Results

t

C2C jitter trendC2C jitter trend

Period jitter trendPeriod jitter trend

t

Part BPart B

Jitter separation Jitter separation methodologymethodology

Dual Dirac modelDual Dirac model

Objective Objective Compare DJ theoretical calculation to measured valuesCompare DJ theoretical calculation to measured values Verification of the modelVerification of the model

RealizationRealization Forcing as appose to Forcing as appose to

Calculation of for square modulation Calculation of for square modulation

mod

1 1

/ 2 2CW

CW CW dev

Deviation of one cycle

fDJ

f f f f

DJ DJ DJ DJ

DJ

Tail fit separation methodTail fit separation method

Objective Objective Testing the connectionTesting the connection Verification of the modelVerification of the model

RealizationRealization Measuring RJ using low amp. waveMeasuring RJ using low amp. wave Calculating predicted DJCalculating predicted DJ Comparing results to the scopes separation applicationComparing results to the scopes separation application

TJ(BER) 2Q(BER) DJ( )

Tail fit – Results analysisTail fit – Results analysis Manually measured resultsManually measured results

Scope application resultsScope application results

12 12

0.17

37.5

(10 ) 2 (10 ) 39.88

RJ ns

p p ns

RJ ns

DJ

TJ Q DJ

12

0.165 2.9%

38 1.3%

(10 ) 40.534 1.6%

RJ ns

ns

ns

diff

DJ diff

TJ diff

Fourier transport methodFourier transport method

Objective Objective Analyzing the connection between modulation parameters and FFT parametersAnalyzing the connection between modulation parameters and FFT parameters Detecting DJ causing frequencyDetecting DJ causing frequency

RealizationRealization FM sin modulation for simple FFTFM sin modulation for simple FFT Applying a FFT and measuring the parametersApplying a FFT and measuring the parameters

Fourier ResultsFourier Results FFT peak value is ½ of the DJFFT peak value is ½ of the DJ FFT peak appears at the modulation frequency FFT peak appears at the modulation frequency Additional feature – Ability to find causing frequency of JitterAdditional feature – Ability to find causing frequency of Jitter

RJ-DJ extraction resultsRJ-DJ extraction results FFT resultsFFT results

Part CPart C

Jitter statistic Jitter statistic analysisanalysis

Eye Closure - Bathtub CurveEye Closure - Bathtub Curve

Objective Objective Comparing eye closure at different BER’sComparing eye closure at different BER’s Finding relation between FM modulation (System Noise) and eye closureFinding relation between FM modulation (System Noise) and eye closure

RealizationRealization Eye analysis using Bathtub curveEye analysis using Bathtub curve DJ calculation comparison to measured eye closureDJ calculation comparison to measured eye closure

Eye closure - ResultsEye closure - Results

Eye closure at BER(10-3) Eye closure at BER(10-3) Eye closure at BER(10-12) Eye closure at BER(10-12)

For low RJ we reach eye closure at freq. dev.=28 KHzFor low RJ we reach eye closure at freq. dev.=28 KHz

Frequency Deviation 25 KHz Frequency Deviation 20 KHz

mod

1 1/ (sin)

/ 2 2

1 1 50049.43 50 1

10 10 28 / 2 2

CWp p

CW CW dev

ns ns UIM M K

fDJ RMS

f f f f

Margins MeasurementMargins MeasurementObjective Objective

Practical example - Acquiring ability to test marginality using bathtub curvePractical example - Acquiring ability to test marginality using bathtub curve

ResultsResults - Measuring margins by the following formula - Measuring margins by the following formula

When TJ(System) is measured and TJ(Sampler) is given to the studentWhen TJ(System) is measured and TJ(Sampler) is given to the student

arg 1UI SYSTEM SAMPLERM in TJ TJ

RJ-DJ identificationRJ-DJ identification

Objective Objective Acquiring ability to make visual RJ-DJ separation using the Bathtub curveAcquiring ability to make visual RJ-DJ separation using the Bathtub curve Getting acquainted with RJ, DJ separation on the bathtub curveGetting acquainted with RJ, DJ separation on the bathtub curve Proving the relation between slope and RJProving the relation between slope and RJ

RealizationRealization Increasing RJ and DJ separately and analyzing using bathtub curveIncreasing RJ and DJ separately and analyzing using bathtub curve

TJ~DJ

TJ~RJ

RJ-DJ ResultsRJ-DJ Results Mainly DJ Mainly RJ

Low freq. dev.

High freq. dev.

Additional MaterialAdditional Material General background for Jitter, Jitters components and its General background for Jitter, Jitters components and its

causescauses

Arbitrary waveform generator overviewArbitrary waveform generator overview

Scope usage short overviewScope usage short overview

ConclusionsConclusions We focused on clock Jitter due to its simpler structureWe focused on clock Jitter due to its simpler structure

The implementation of the experiment requires very simple environmentThe implementation of the experiment requires very simple environment

The project contains great variety of tests that allow flexibility at the final The project contains great variety of tests that allow flexibility at the final experiment experiment

Left out the DCD measurement due to required hardware complexityLeft out the DCD measurement due to required hardware complexity

Topics for next experiments: Data Jitter, N-cycle JitterTopics for next experiments: Data Jitter, N-cycle Jitter