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Jitter Experiment Final presentation

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

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Jitter Experiment Final presentation

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  1. Spring 2008 Jitter ExperimentFinal presentation Performed by Greenberg Oleg Hahamovich Evgeny Supervised by Mony Orbah

  2. 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

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

  4. Experiment Environment Jitter created by FM 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 “EZJIT Plus” options were implemented using DSO80204B Oscilloscope model

  5. Experiment Overview • Introduction • Part A – Jitter basics • Eyediagram • Introduction to histogram • Analyzing relation between Jitter types • Mathematical connection between Jitter types • Part B – Jitter separation methodology • Dual-Dirac model definition • Tail fit separation method • Fourier transform separation method • Part C – Jitter statistic analysis • Eye closure using bathtub curve • Margins measurement • RJ-DJ identification • Appendixes

  6. Part A Jitter basics

  7. 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

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

  9. 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

  10. Jitter Measurement Types

  11. Std Dev Measurement Results

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

  13. Part B Jitter separation methodology

  14. 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

  15. 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

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

  17. 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

  18. Fourier Results FFT peak value is ½ of the DJ FFT peak appears at the modulation frequency Additional feature – Ability to find causing frequency of Jitter RJ-DJ extraction results FFT results

  19. Part C Jitter statistic analysis

  20. 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

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

  22. 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

  23. RJ-DJ identification TJ~DJ TJ~RJ 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

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

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

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

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