Jitter Experiment Final presentation Performed by Greenberg Oleg Hahamovich Evgeny Spring 2008 Supervised by Mony Orbah

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

Motivation for Jitter Analysis Uniform Requirements Uniform Requirements Clock Statistic Analysis Clock Statistic Analysis Short Time Measurements Extrapolation Short Time Measurements Extrapolation Determining Jitter Components Determining Jitter Components

Experiment Environment Tabor Arbitrary Waveform Generetor 2571a Maximum frequency 100 MHz Ability to create different Modulation types Agilent Oscilloscope MS08104A Bandwidth 1 GHz Sample Rate 4 GS/s “EZJIT” Package Jitter created by FM “EZJIT Plus” options were implemented using DSO80204B Oscilloscope model

Experiment Overview Introduction Introduction Part A – Jitter basics Part A – Jitter basics Eye diagramEye diagram Introduction to histogramIntroduction to histogram Analyzing relation between Jitter typesAnalyzing relation between Jitter types Mathematical connection between Jitter typesMathematical connection between Jitter types Part B – Jitter separation methodology Part 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 analysis Part C – Jitter statistic analysis Eye closure using bathtub curveEye closure using bathtub curve Margins measurementMargins measurement RJ-DJ identificationRJ-DJ identification Appendixes Appendixes

Part A Jitter basics

Eye Diagram Objective  Introduction to eye diagram  Noise influence on eye opening (sampling margins) Realization  Creating phase noise using FM modulation  Analyzing eye diagram for a clean signal vs. “noisy” (modulated) signal Clean (un-modulated) signal FM modulated signal

Histogram Objective  Introduction to Histogram  Characterizing Jitter using Histogram Realization  Histogram for voltage level  Histogram for Jitter measurement Sin wave histogram TIE histogram for FM modulation by a sin wave

Jitter Measurement Types Objective  Visualization of differential / integration relation between jitter measurement types  Calculating ratio of Std Dev between different jitter measurement types Realization  Using FM modulation analyzing TIE, C2C and periodic Jitter trends  Increasing RJ by lowering the amplitude and the slope of the wave

Jitter Measurement Types

Std Dev Measurement Results

TIE jitter trend Trend Measurement Results C2C jitter trend Period jitter trend

Part B Jitter separation methodology Jitter separation methodology

Dual Dirac model Objective  Compare DJ theoretical calculation to measured values  Verification of the model Realization  Forcing as appose to Calculation of for square modulation

Tail fit separation method Objective  Testing the connection  Verification of the model Realization  Measuring RJ using low amp. wave  Calculating predicted DJ  Comparing results to the scopes separation application

Tail fit – Results analysis Manually measured results Manually measured results Scope application results Scope application results

Fourier transport method Objective  Analyzing the connection between modulation parameters and FFT parameters  Detecting DJ causing frequency Realization  FM sin modulation for simple FFT  Applying a FFT and measuring the parameters

Fourier Results FFT peak value is ½ of the DJ FFT 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 Jitter Additional feature – Ability to find causing frequency of Jitter RJ-DJ extraction resultsFFT results

Part C Jitter statistic analysis

Eye Closure - Bathtub Curve Objective  Comparing eye closure at different BER’s  Finding relation between FM modulation (System Noise) and eye closure Realization  Eye analysis using Bathtub curve  DJ calculation comparison to measured eye closure

Eye closure - Results Eye closure at BER(10-3) Eye closure at BER(10-12) For low RJ we reach eye closure at freq. dev.=28 KHz Frequency Deviation 25 KHz Frequency Deviation 20 KHz

Margins Measurement Objective  Practical example - Acquiring ability to test marginality using bathtub curve Results - Measuring margins by the following formula When TJ(System) is measured and TJ(Sampler) is given to the student

RJ-DJ identification Objective  Acquiring ability to make visual RJ-DJ separation using the Bathtub curve  Getting acquainted with RJ, DJ separation on the bathtub curve  Proving the relation between slope and RJ Realization  Increasing RJ and DJ separately and analyzing using bathtub curve TJ~DJ TJ~RJ

RJ-DJ Results Mainly DJ Mainly RJ Low freq. dev. High freq. dev.

Additional Material General background for Jitter, Jitters components and its causes General background for Jitter, Jitters components and its causes Arbitrary waveform generator overview Arbitrary waveform generator overview Scope usage short overview Scope usage short overview

Conclusions We focused on clock Jitter due to its simpler structure We focused on clock Jitter due to its simpler structure The implementation of the experiment requires very simple environment The implementation of the experiment requires very simple environment The project contains great variety of tests that allow flexibility at the final experiment The project contains great variety of tests that allow flexibility at the final experiment Left out the DCD measurement due to required hardware complexity Left out the DCD measurement due to required hardware complexity Topics for next experiments: Data Jitter, N-cycle Jitter Topics for next experiments: Data Jitter, N-cycle Jitter