Tektronix 80SJNB Online User Manual

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OnlineUserManual

80SJNB Advanced Jitter, Noise, and BER Analysis Software

077 --0011--00

Adapted from the 80SJNB Online Help Version 076--0022--00

www.tektronix.com

Copyright © Tektronix, Inc. All rights reserved. Licensed software products are owned by Tektronix or its subsidiaries or suppliers, and are protected by national copyright laws and international treaty provisions.

Tektronix products are covered by U.S. and foreign patents, issued and pending. Information in this publication supercedes that in all previously published material. Specifications and price change privileges reserved.

TEKTRONIX and TEK are registered trademarks of Tektronix, Inc.

Contacting Tektronix

Tektronix, Inc. 14200 SW Karl Braun Drive P.O. Box 500 Beaverton, OR 97077 USA

For product information, sales, service, and technical support:

H In North America, call 1-800-833-9200.

H Worldwide, visit www.tektronix.com to find contacts in your area.

Table of Contents

Welcome to the Jitter, Noise, and BER Analysis Software iii................

Related Documentation iii...........................................

GPIB Information iii................................................

Relevant Web Sites iv...............................................

Conventions iv....................................................

Types of Online Help Information iv...................................

Using Online Help v...............................................

Feedback vi.......................................................

Getting Started 1............................................

Product Description 1..............................................

Requirements and Restrictions 1......................................

Accessories 1.....................................................

Connecting to a Device Under Test (DUT) 2............................

Deskewing Probes and Channels 2....................................

The Importance of Jitter and Noise Separation 2.........................

Operating Basics 5..........................................

General Information 5..............................................

Navigating the User Interface 9......................................

Setting up the Application for Analysis 15...............................

Saving and Recalling Setup Files 23....................................

Working with Numeric Results 24.....................................

Working with Plots 25...............................................

Parameters 33...............................................

User Settings 33....................................................

Configuration Settings 33............................................

GPIB 35....................................................

Program Example 35................................................

GPIB Commands 35................................................

Variable:Value Command 36..........................................

Measurements Results Queries 39......................................

Error Messages 40..................................................

GPIB Program Example 41...........................................

Application Example 43.......................................

About Application Example 43........................................

Example 44.......................................................

Algorithms 53...............................................

About Measurement Algorithms 53....................................

Test Methodology 53................................................

Correlations 55..............................................

Correlation to Real--Time Oscilloscope Jitter Measurements 55..............

Index 57....................................................

Adapted From the 80SJNB Online Help

Table of Contents

Adapted From the 80SJNB Online Help

Preface

Welcome to the Jitter, Noise, and BER Analysis Software

The 80SJNB Advanced Jitter, Noise, and BER Analysis Software enhances the capabilities of the CSA/TDS8000B and CSA/TDS8200 series Tektronix oscilloscopes. The analysis software includes the following features:

H Advanced jitter and noise analysis

H Separation of jitter and noise

H Perform random and deterministic jitter analysis including BER estimation

H Show results as graphical displays including histograms, spectra, and bathtub

curves

H 2--D eye diagrams that include Correlated Eye, Probability Density Function

(PDF) Eye, and Bit Error Rate (BER) Eye

H Save statistical results to a data file

GPIB Information

In addition to the online help, you can access other information on how to operate the oscilloscope and application through the following related documents.

H Relevant Web Sites

H GPIB Information

H Types of Online Help Information

For information on how to operate the oscilloscope and use the application--specific GPIB commands, refer to the following items:

H The online programmers guide for your oscilloscope can provide details on

how to use GPIB commands to control the oscilloscope.

H The programming example.

Adapted From the 80SJNB Online Help

iii

Preface

Relevant Web Sites

Conventions

The Tektronix web site offers the following information:

H Understanding and Characterizing Jitter Primer, literature number

55W--16146--x.

H Jitter analysis details on the www.tektronix.com/jitter web page.

You can also find useful information in the Fibre Channel -- Methodologies for Jitter and Signal Quality Specification – MJSQ on the www.t11.org web site.

Online help topics use the following conventions:

H The terms “80SJNB application” or “application” refer to the 80SJNB Jitter,

Noise and BER Analysis software.

H The term “oscilloscope” refers to the product on which this application runs.

H The term “select” is a generic term that applies to the two mechanical

methods of choosing an option: with a mouse or with the Touch Screen.

H The term “DUT” is an abbreviation for Device Under Test.

H User interface screen graphics are from a CSA8200 Communications Signal

Analyzer. There may be minor differences depending on the instrument model and software versions.

H When steps require a sequence of selections using the application interface,

the “>” delimiter marks each transition between a menu and an option. For example, one of the steps to recall a setup file would appear as File > Recall Settings.

Types of Online Help Information

The online help contains the following topics:

H Getting Started topics briefly describes the application and its requirements.

H Operating Basics topics cover basic operating principles of the application.

The sequence of topics reflects the steps you perform to operate the application.

H Parameters topics cover the User and Configuration default settings.

Adapted From the 80SJNB Online Help

Using Online Help

Preface

H Application Examples topics demonstrates how to use jitter measurements to

identify a problem with a waveform. This should give you ideas on how to solve your own measurement problems.

H GPIB Command Syntax topics contain a list of arguments and values that

you can use with the remote commands and their associated parameters.

Online help has many advantages over a printed manual because of advanced search capabilities. The main (opening) Help screen shows a series of book icons and three tabs along the top menu, each of which offers a unique mode of assistance:

H Table of Contents (TOC) tab -- organizes the Help into book--like sections.

Select a book icon to open a section; select any of the topics listed under the book.

H Index tab -- enables you to scroll a list of alphabetical keywords. Select the

topic of interest to display the corresponding help page.

H Find tab -- allows a text--based search. Follow these steps:

1. Type the word or phrase you want to find in the search box.

2. If the word or phrase is not found, try the Index tab.

3. Select some matching words in the next box to narrow your search.

4. Choose a topic in the lower box, and then select the Display button.

NOTE. The Find tab function does not include words found in graphics.

NOTE. Green--underlined text indicates a hyperlink to another topic. For

example, select the green text to jump to the topic on Feedback to contact T ektronix.

When you use a mouse, you can tell when the cursor is over an active

hyperlink because the arrow cursor changes to a small pointing hand cursor.

Adapted From the 80SJNB Online Help

Preface

Feedback

General Information

Tektronix values your feedback on our products. To help us serve you better, please send us suggestions, ideas, or other comments you may have about your application or oscilloscope.

You can email your feedback to techsupport@tektronix.com, FAX at (503)627--5695, or by phone. Please be as specific as possible and include the following information:

H Oscilloscope model number, firmware version number, and hardware

options, if any.

H Module and probe configuration. Include model numbers and the channel/

slot location.

H Serial data standard.

Application- Specific

Information

H Signaling rate.

H Your name, company, mailing address, phone number, FAX number.

NOTE. Please indicate if you would like Tektronix to contact you regarding your suggestion or comments.

H 80SJNB Software version number.

H Description of the problem such that technical support can duplicate the

problem.

H If possible, save the oscilloscope waveform file as a .wfm file.

H If possible, save the oscilloscope and application .stp setup files. Refer to

Saving a Setup File.

Once you have gathered this information, you can contact technical support by phone or through e--mail. If using e--mail, be sure to enter ”80SJNB Problem” in the subject line, and attach the .stp and .wfm files.

To include screen shots, from the oscilloscope menu bar, select File > Export. Waveform… In the Export dialog box, enter a file name with a .bmp extension and select Save. The file is saved in the C:\My Documents\TDSCSA8000\UI directory.

Adapted From the 80SJNB Online Help

Getting Started

Product Description

The 80SJNB software application enhances the capabilities of the CSA/ TDS8000B and CSA/TDS8200 series Tektronix oscilloscopes by providing Jitter, Noise, and BER analysis.

You can use this application to do the following tasks:

H Jitter and noise analysis from 0.5 Gb/s to greater than 60 Gb/s

H Jitter and noise separation (see the importance of jitter and noise separation)

H Perform random and deterministic jitter analysis including BER estimation

H Show results as graphical displays

H 2--D eye diagrams that include Correlated Eye, Probability Density Function

(PDF) Eye, and Bit Error Rate (BER) Eye

H Save results to a data file

H Save and recall instrument

Requirements and Restrictions

Operating System. This application requires the Microsoft Windows 2000 operating system. Contact Tektronix about purchasing the necessary upgrades for your instrument.

Memory. This application requires 512 MB of memory (minimum) to perform. To verify the amount of installed memory, minimize the Tekscope application, then select Start > Control Panel > System. If less than 512 MB is reported, contact Tektronix about purchasing the necessary upgrades for your instrument.

Keyboard and Mouse. You will need to use a keyboard to enter new names for some file save operations. A mouse is not required but simplifies screen selections.

Accessories

There are no standard accessories for this product. However, you can refer to the product datasheet available on the Tektronix web site for information on optional accessories relevant to your application.

setups

Adapted From the 80SJNB Online Help

Getting Started

Connecting to a Device Under Test (DUT)

You can use any compatible probe or cable interface to connect between your DUT and the instrument.

WARNING. To avoid electric shock, remove power from the DUT before attaching probes. Do not touch exposed conductors except with the properly rated probe tips. Refer to the probe manual for proper use.

Refer to the General Safety Summary in your oscilloscope manual.

Deskewing Probes and Channels

To ensure accurate results for two--channel measurements, it is important to first deskew the probes or cables and oscilloscope channels before you take measurements.

NOTE. Deskewing is performed from the CSA/TDS8000 series instrument application, not from the 80SJNB application. Refer to the CSA8000 & TDS8000 User Online Help for information and procedures for deskewing probes and channels.

The Importance of Jitter and Noise Separation

Jitter is an important characteristic to analyze for serial data links, but the analysis should not stop at just jitter. To properly evaluate a data link, it is necessary to analyze both jitter and noise.

Two components need to be added to the traditional jitter analysis:

H The noise/vertical eye closure should be considered in a manner very similar

to that of jitter/horizontal eye closure.

H Jitter measurements based on the threshold crossing of a finite--speed

transition should include vertical noise influence.

Depending on the magnitude of the vertical noise and the transient response of the transmitter and transmission channel, the magnitude of this influence can vary widely. Ultimately the jitter and noise analysis allows for accurate BER projections for the targeted communication link.

Tektronix has written a detailed document explaining the importance of jitter and noise separation.

Adapted From the 80SJNB Online Help

Go to the Tektronix Web site:

www.tektronix.com

At the Tektronix home page, select oscilloscopes > sampling

You can download a pdf of the white paper titled:

Tektronix CSA/TDS8200 Jitter Analysis Application: Jitter and Noise Analysis, BER Estimation Descriptions

Getting Started

Adapted From the 80SJNB Online Help

Getting Started

Adapted From the 80SJNB Online Help

Operating Basics

General Information

The Operating Basics book covers the following tasks:

H Navigating the user interface

H User interface information

H Using oscilloscope functions

H Setting up the application

H Viewing the measurement results as plots

H Exporting Plot Files

H Saving and recalling setup files

Starting the 80SJNB

Application

Returningtothe

Oscilloscope Application

There are several ways to start the 80SJNB application.

H If the TDS/CSA8000 Series application is minimized, you can start the

80SJNB application by selecting the shortcut located on the Windows desktop area.

H If the TDSCSA8000 Series oscilloscope application is running and open,

you can use the Applications menu on the menu bar and select the 80SJNB application.

H Use the Windows Start menu by selecting Start > Programs > Tektronix

TDSCSA8000 > 80SJNB > 80SJNB.

The 80SJNB application fills the entire screen and hides the oscilloscope application. To return to the oscilloscope display, press the Back to Scope button

in the toolbar.

You can also minimize the 80SJNB application or exit the 80SJNB application entirely.

Adapted From the 80SJNB Online Help

Operating Basics

Returning to the 80SJNB

Application

The CSA/TDS8000 oscilloscope application fills the entire screen. If the 80SJNB application is already running but the oscilloscope application is displayed on top, bring the 80SJNB application to the front using the following methods.

H Press the App button on the oscilloscope toolbar.

H Select Switch to 80SJNB from the Applications pull--down file menu.

If you have a keyboard attached, you can switch between running applications by pressing the Alt + Tab keys.

Minimizing and Maximizing the

Application

Exiting the Application

Directory Structure for the

80SJNB Application

To minimize the application to the Windows task bar, select the button in the application menu bar.

To maximize the application, select the minimized application from the Windows task bar. Alternately, if you have a keyboard attached, you can switch between displayed applications by pressing Alt + Tab keys.

To exit the application, select File > Exit or the application menu bar.

Installation Directory

The 80SJNB software is installed in the following directory:

C:\Program Files\TekApplications\80SJNB

Save and Recall Directory

The directory structure used for saving and recalling setup files and exporting data depends on how the Windows operating system is configured for networking and login purposes.

command button in the

command

H If users are required to log in, the save, recall, and export default location is:

Adapted From the 80SJNB Online Help

File Name Extensions

Operating Basics

C:\Documents and Settings\username\My Documents.

H If no login requirements are set, the default location is:

C:\My Documents.

Extension Description

.bmp File that uses a bitmap format

.csv File that uses a comma separated value format

.stp 80SJNB application setup file

.jpg File that uses a joint photographic experts group format

.mat File that uses native MATLAB binary format

.png File that uses a portable network graphics format

.txt File that uses an ASCII format

File Menus

Tips on the 80SJNB User

Interface

You can use the File menus to save and recall different application setups and recently accessed files.

CAUTION. Do not edit a setup file or recall a file not generated by the application.

Menu/function Description or function

Save Settings Saves the current application settings in a .stp file

Recall Settings Browse to select an application setup (.stp) file to recall; restores the application and

Export Waveform Exports the underlying waveform correlated pattern data used for processing

Print Prints the displayed plots and the detailed statistics list

Print to File Creates a .prn file of the displayed plots and a detailed statistics list

Exit Exits the application

oscilloscope to the values saved in the setup file

Here are some tips to help you with the application user interface.

The toolbar provides you with most of the functions you need to configure the settings, start the acquisition, and control the numerical and plot displays.

H The Configure button

displays a dialog box to configure the target source for measurement and controlling the most relevant oscilloscope setups.

H Pressing the Run button

plot displays, and then starts the acquisition and processing cycle.

Adapted From the 80SJNB Online Help

first clears all current measurement data and

Operating Basics

Oscilloscope Settings

H The Free Run button toggles between blue

sequence) and orange

H Use the plot selection button in the plot displays to access the drop--

down menu for tasks to perform for that plot window, such as assigning a new type of plot display.

You should return the oscilloscope to its default state before launching the 80SJNB Configuration dialog box. All other acquisitions and math waveforms should be off, as well as all measurements, waveform databases, masks, and histograms. You should not have to make changes to the oscilloscope settings via the oscilloscope UI to successfully acquire data with the 80SJNB application. The most relevant oscilloscope settings are accessible using the Configuration dialog box of the 80SJNB application.

Some test setups require oscilloscope settings (such as wavelength and external attenuation). Make changes to the oscilloscope settings before running the analysis.

NOTE. Changing oscilloscope settings while the 80SJNB application is acquiring data may cause errors, unpredictable results, or failure.

for Free Run On.

for Free Run Off (single

About the Results

Clearing Results

To bring the CSA/TDS application to the front of the display, press the Back to

Scope button use the Alt + Tab keys to switch between applications if you have a keyboard attached.

There are two ways to view analysis results: as numeric data and as graphical plots.

You can log the results data to .csv files for viewing in a spreadsheet, database, text editor or data analysis program.

Press the Clear Data You may want to clear the data before acquiring new data or between cycles when the Sequence mode is set to free--run.

NOTE. The numeric results and plot files are erased each time a new acquisition cycle is started by the user.

or minimize the 80SJNB application. Alternately, you can

button to remove the existing plot displays and results.

Adapted From the 80SJNB Online Help

Operating Basics

About Plotting

The application displays the results as 2--dimensional plots for more comprehensive analysis. Before or after you take measurements, you can select to display a single plot, two plots or four plots. You can select the type of data you want to view in each plot window.

Navigating the User Interface

Windows User Interface

About the User Interface

The application uses a Microsoft Windows--based user interface.

NOTE. The oscilloscope application is hidden when the 80SJNB application is running and not minimized.

Adapted From the 80SJNB Online Help

Operating Basics

User Interface Items Definitions

Item Description

Area Visual frame that encloses a set of related options

Box Use to define an option; enter a value with the Keypad or a Multipur-

pose knob

Browse Displays a window where you can look through a list of directories and

files

Check box Use to select or clear an option

Command button Initiates an immediate action, such as the Start command button in the

Control panel

Keypad On--screen keypad that you can use to enter numeric values

Menu All options in the application window (except the Control panel) that

display when you select a menu bar item

Menu bar Located along the top of the application display and contains

application menus

Status bar Line located at the bottom of the application display that shows the

acquisition status and the latest Warning or Error message

Virtual keyboard On--screen keyboard that you can use to enter alphanumeric strings,

such as for file names

Adapted From the 80SJNB Online Help

80SJNB User Interface

Information

Operating Basics

Item Description

Scroll bar Vertical or horizontal bar at the side or bottom of a display area that

you use to move around in that area

Tool bar Located along the top of the application display and contains

application quick launch buttons

About Navigation

The application provides you with several means to display the results:

H The drop--down menus available in the menu bar allows for screen configu-

ration (one, two, or four plots, summary or full numeric results table)

H The buttons in the tool bar allow for screen configuration

H The drop--down menus available in the plot display windows allow you to

choose from the available plots, as well as Copy, Examine, and Export plots

H The status bar at the bottom of the screen contains progress information and

displays error conditions detected

H Double clicking on a displayed graph opens the plot in a Matlab window.

Matlab provides additional display capabilities such as panning, zooming, data cursors, and 3D rotation. The Examine… button from the drop--down menu of the plot also opens the Matlab window.

Adapted From the 80SJNB Online Help

Operating Basics

About the 80SJNB Tool Bar

The toolbar provides you with most of the functions you need to configure the settings, start the acquisition, and control the numerical and plot displays. Most tasks are also available using the drop--down lists from the File menu bar.

H Configure button . Use the Configure button to display the Configura-

tion dialog box, allowing you to select and configure the source for measurements and control key oscilloscope setups. The Configuration button is disabled during the acquisition and processing cycle.

H Free Run on/off button . Use the Free Run button to select the sequence

mode (free run on or off).

When OFF, the button remains blue and the acquisition and processing cycle completes one pass over the entire pattern. Off is the default mode.

When Free Run is ON, the button turns orange acquisition and processing cycle will repeat until stopped by the user. The

indicating that the

Adapted From the 80SJNB Online Help

Operating Basics

correlated components are averaged with previous data while the uncorrelated components are accumulated for increased statistical content. At the completion of each acquisition cycle, the plots and measurements are updated.

If you want to halt a Free Run cleanly, select the

button. This converts the Free Run mode to Single Sequence mode, so that the acquisition stops when the cycle is complete.

H Run button

. Use the Run button to start the acquisition and processing cycle. Once the run button is pressed, do not change any instrument settings. When the Run button is pressed, all current measurement data and plot displays are cleared. During the acquisition and processing cycle the Configuration and Run buttons are disabled.

H Pause button

. Use the Pause button to interrupt the current acquisition and processing cycle. Press the button again to resume the cycle. This can be useful when the acquisition is set to Free Run, allowing you to halt the acquisition and processing cycle so you can view and save the measurement data between cycles.

H Stop button

. Use the Stop button to end the acquisition and processing cycle. While in Single Sequence mode, stopping the cycle produces no results and you must press the Start button to start a new cycle.

H Clear Data button

. Use the Clear Data button to clear all results and plot displays. If Free Run is set to ON (cumulating previous data with new), you can clear the existing results and plots during the processing cycle, thus starting a new acquisition and processing cycle.

H Plot Display . Use the window pane buttons to display between

1, 2, or 4 plots. The number of plot displays can be changed at any time.

H Numeric Results Display

complete list of statistics with no plots displayed.

H Return to Scope

oscilloscope display to the front of the screen.

Adapted From the 80SJNB Online Help

. The results button changes the display to a

. Use this button to bring the CSA/TDS 8000

Operating Basics

Menu Bar Navigation Tree

File View Options Help

Matlab User Interface

Information

Save Settings Recall Settings Export Waveform Print Print to File Export

1--up 2--up 4--up Show Summary Full Results

Configuration Settings

Help Contenst and Index About 80SJNB

Matlab® User Interface

The 80SJNB application includes Matlab plots to provide further data analysis and visualization of the plot displays.

Matlab provides multiple capabilities to display and annotate the plot diagrams, including:

H Pan and Zoom

H 2D and 3D visualization

H Rotation

H Data Cursors

H Color enhancements

Matlab is a product distributed by MathWorks. You can view the Matlab documentation and tutorials on their website: http://www.mathworks.com

Adapted From the 80SJNB Online Help

Setting up the Application for Analysis

Operating Basics

Configuring Sources

The tool bar provides a Configuration button to set up the application.

Use the Sequence button continuously (free run) or stop after one cycle is complete.

After setting up the application, you can select the Run button acquisition and processing cycle.

After the acquisition and processing cycle has completed, you can view the results as numerical statistics or graphically.

Before making jitter and noise measurements, you need to select and configure the signal source.

Use the Configure button

In the Configuration dialog box, select the signal source and define the acquisition parameters. Some parameters (such as the Clock Recovery, Phase Reference Sources, and the optical signal conditioning) are pre--loaded by reading the oscilloscope’s module installation record.

Press the AutoSync to Selected Waveform button to have the 80SJNB application automatically obtain and enter the following information from the signal applied to the channel defined as the Signal Source:

to have the acquisition and processing of data run

to start the

to display the Configuration dialog box.

H Data Pattern Rate

H Data Pattern Length

H Data:Clock Ratio

Adapted From the 80SJNB Online Help

Operating Basics

NOTE. The extent of the auto discovery depends on the configuration of the Pattern Sync setup in the oscilloscope. Refer to the 8000 Series online help system for details about the Pattern Sync settings.

Selecting Clock Recovery

The PatternSync Trigger module requires a data synchronous clock input. When using a clock derived from a module that provides a clock recovery output, use this dialog box to select the channel source and its frequency.

These settings are grayed out if no modules with clock recovery are detected at application startup.

The Rate setting is limited to the capabilities of the selected module. The numeric keypad is unavailable for use unless the module is capable of USER defined rates.

Selecting Phase Reference

You can use a Phase Reference module (such as the 82A04) to reduce the trigger jitter of the signal source, thus increasing the jitter measurement accuracy.

Adapted From the 80SJNB Online Help

Operating Basics

If using a Phase Reference module, set the channel source and the frequency of the applied clock.

These settings are grayed out if a Phase Reference module is not detected at application startup. If a Phase Reference module is detected, you have the option to not use the module by selecting None as the Source.

Selecting the Data Pattern

Defining the Data Pattern requires that you define both the data rate of the signal source and the pattern length in bits. You can choose the data rate from a predefined set of communication standards or enter a value with the numerical keypad.

NOTE. Selecting a data rate that does not match the communication standard that is set in the instrument’s Horizontal Communication Standard setting dialog box causes the oscilloscope setting to change to User.

Selecting the Optical Signal Conditioning

You can apply an optical filter to optical input signals. Use this control to select what type of filtering, if any, you want performed on the selected optical channel. The available filters depend on the capabilities of the optical module.

If the Filter is set to None, you can use the Bandwidth box to select the bandwidth of the channel. The available bandwidth selections depend on the capabilities of the optical module.

Adapted From the 80SJNB Online Help

Operating Basics

Selecting the Pattern Sync

The Pattern Sync area is where you set the location of the PatternSync Trigger module and the data--to--clock ratio.

Upon starting the 80SJNB application, the Sync Source is preset to the first location (lowest numbered channel) of an installed PatternSync Trigger module.

The default value for the data--to--clock ratio is 1:1. The first value represents the data rate and the second value represents the clock rate. The Data to Clock valid rates range from 128:1 to 1:8, with one of the references values always being 1.

Selecting the Source

The application takes measurements on waveforms specified as sources (also called input sources). The source can be a channel (CH1 through CH8) or a math waveform (if one has been defined). Any defined math waveform can be used, whether it’s defined in the 80SJNB configuration as a differential setup or in the CSA/TDS8000 instrument setups. (Defining a math waveform in the CSA/ TDS8000 application must be done before launching the 80SJNB application.)

When selecting a Data Source, all other channels and Math waveforms will be turned off. If any channels or Math, other than the Data Source are activated after launching the 80SJNB application, an error message will prompt the user to deactivate all additional waveforms before running the application. All other waveform databases, measurements, histograms and masks on the base scope need to be turned off, as well. If any of these conditions exist when starting the acquisition and processing cycle, you will be prompted to turn these off before you can continue.

Adapted From the 80SJNB Online Help

Operating Basics

Selecting the Diff … button displays the dialog box to create a differential Math waveform by defining a positive and negative waveform source (the negative waveform source is subtracted from the positive waveform source). This generates a single mathematical waveform that the 80SJNB application can use as the waveform measurement source.

Configuring User Settings

More complex math expressions are available using the CSA/TDS8000 series instrument math dialog box. Refer to the instruments online help. These must be defined before launching the 80SJNB application.

The User Settings affect how measurements are made and displayed. The User Settings are saved with the 80SJNB application whenever it is closed so that restarting the application results in using the same User Settings.

Adapted From the 80SJNB Online Help

Operating Basics

Changes to User Settings are reflected in the current plots and results.

Setting the Decision Threshold

The Decision Threshold specifies the level at which to determine the crossing points on the edges of the measured waveform.

When set to Absolute, the decision threshold uses the absolute value provided in volts (electrical) or watts (optical).

When set to Normalized, the decision threshold is calculated based on waveform data according to the percent value of the signal amplitude.

Setting the Time Unit

The Time Unit sets the units (Seconds or Unit Intervals) used when displaying the measurement results.

Setting the Sampling Phase

The Sampling Phase determines where the sampling point is located within the bit interval.

About Measurements

When set to Seconds, the sampling point uses the absolute value entered. Zero seconds is at the center of the bit interval.

When set to Unit Intervals, the sampling point is calculated based on the bit interval. Zero UI is the center of the unit interval.

Setting the Measurement Bit Error Rate

The Measurement BER determines the rate for which the measurements are predicted.

About Displaying Measurements

You can use the tool bar to select how the results are displayed: numeric results, plots (up to four), or a combination.

What do you want to do?

Display the definitions of Jitter measurements.

Display the definitions of Noise measurements

Measurement Algorithms

Go to Working with Numeric Results

Go to Working with Plots

Adapted From the 80SJNB Online Help

Jitter Measurement Definitions

Jitter Measurements Description

Random Jitter

RJ (RMS) Measured Random Jitter

RJ(h) (RMS) Horizontal component of random jitter

RJ(v) (RMS) Vertical component of random jitter induced by noise

converted to jitter through an average slew rate

Deterministic Jitter

DJ Measured Deterministic Jitter

DDJ Data Dependant Jitter

DCD Duty Cycle Distortion

PJ Measured Periodic Jitter (peak--to--peak)

PJ(h) Horizontal component of periodic jitter (peak--to--peak)

PJ(v) Vertical component of periodic jitter (peak--to--peak)

induced by noise converted to jitter through an average slew rate

Total Jitter @ BER

TJ (1E--12) Total Jitter at user-- specified BER

Eye Opening (1E--12) Horizontal Eye Opening at user specified BER

Dual Dirac

RJ(d--d) Random Jitter computed in the Dual Dirac model

DJ(d--d) Deterministic Jitter computed in the D ual Dirac model

Operating Basics

Noise Measurement Definitions

Noise Measurements Description

Random Noise

RN (RMS) Measured Random Noise

RN(v) Vertical component of random noise

RN(h) Horizontal component of random noise induced by jitter

Deterministic Noise

DN Measured Deterministic Noise

DN Data Dependant Noise

DDN(level 1) Data Dependant Noise on logical level 1

DDN(level 0) Data Dependant Noise on logical level 0

PN Measured Periodic Noise

PN(v) Vertical component of periodic noise (peak--to--peak)

PN(h) Horizontal component of periodic noise (peak--to--peak)

Total Noise @ BER

TN (1E--12) Total Noise at user-- specified BER

Eye Opening (1E--12) Eye Opening at user--specified BER

Eye Amplitude The amplitude of the eye computed as the mean--to--

converted to noise through an average slew rate

induced by jitter converted to noise through an average slew rate

mean of logical 1 and logical 0 bit levels sampled at the user defined Sampling Phase.

Data Dependant Noise

Adapted From the 80SJNB Online Help

Operating Basics

Acquiring Data

About Taking Measurements

You should return the oscilloscope to its default state before launching the 80SJNB. All other acquisitions and math waveforms should be off, as well as all measurements, waveform databases, masks, and histograms. You should not have to make changes to the oscilloscope settings via the oscilloscope UI to successfully acquire data with the 80SJNB application. The most relevant oscilloscope settings are accessible using the Configuration dialog box of the 80SJNB application.

Some test setups require oscilloscope settings (such as wavelength and external attenuation). Make changes to the oscilloscope settings before running the analysis.

Steps to Acquire Data

To acquire data from waveforms and take measurements, follow these steps:

1. Select application according to your setup and signal type.

2. Select single acquisitions and processing cycles. When in Free Run mode, the data correlated acquisition continues until converging, while the uncorrelated data acquisition, processing, and accumulation of results continues until stopped by the user.

3. Select

To stop the acquisition, do one of the following:

H If you wish to stop the acquisition and processing cycle before it completes,

select waveform and then realize you would like to change the configuration.

H If you wish to interrupt the acquisition and processing cycle, select

Select a second time to resume the acquisition.

H If you wish to halt a Free Run mode cleanly, toggle the Sequence

button. This will convert the Free Run mode (indicated by the orange button) to Single cycle mode (indicated by the blue button) so that the acquisition stops when the cycle is complete. Single cycle is the default mode.

to display the Configuration dialog box and configure the

to toggle the acquisition mode between free run (continuous) and

to start the acquisition and processing cycle.

. This may be useful if you have started a sequence on a long

Use the Clear Data button to delete all measurement results and plots.

Adapted From the 80SJNB Online Help

Saving and Recalling Setup Files

You can use the File menus to save and recall different oscilloscope and application setups. Setup files store the oscilloscope and application settings.

CAUTION. Do not edit a setup file or recall a file not generated by the application.

Operating Basics

Saving a Setup File

Recalling a Saved Setup

File

To save the 80SJNB application and oscilloscope settings to a setup file, follow these steps:

1. Select File > Save Settings to open the Save dialog box.

2. In the file browser, select the directory in which to save the setup file.

3. Use the keyboard to enter a new file name.

The application appends a ”.STP” extension to the name of the file.

4. Save the setup file. If the selected filename already exists, a confirmation dialog appears that allows you to cancel the operation.

NOTE. The application saves the oscilloscope setup.

To recall the application and oscilloscope settings from saved setup files, follow these steps:

1. Select File > Recall Settings to open the Recall dialog box.

2. In the Recall dialog box, select the directory from which to recall the setup

file.

3. Select a setup file name, and then select Open.

CAUTION. Do not edit setup files. If you try to recall a setup file that has been edited, the recall operation fails.

Adapted From the 80SJNB Online Help

Operating Basics

Working with Numeric Results

After an analysis is complete, you can display the results as numeric data in either a summary or detailed table.

The summary table contains the noise and jitter measurements but not the breakdown of the measurements, allowing room for the plot displays.

The detailed table (when selected) expands to fill the entire screen, removing any plot displays.

You can easily switch between summary and detailed numeric displays with the

use of the numeric results button

To hide the summary table and provide more room for the plot displays, click on the tab of the numeric data table. Clicking the tab again redisplays the summary data table.

and the plot window buttons .

Adapted From the 80SJNB Online Help

Operating Basics

Here you can see that the plot windows fill the entire screen and the tab for the numeric details is showing at the bottom of the screen.

Working with Plots

You can display plots in a variety of layouts using the tool bar. One, two, or four plots can be displayed using the plot display buttons

to a summary table of data. To remove the plots entirely from the display, select

the Show Numeric Results button

If the plots have been removed from the display, redisplay the plots by either selecting one of the plot display buttons or click on the tab of the data table.

Adapted From the 80SJNB Online Help

in the toolbar. When displaying plots, the results data table changes

on the tool bar.

Operating Basics

Selecting and Viewing

Plots

To select and view a plot, follow these steps:

1. Select one of the plot views plots).

2. For each plot window, select a type of plot to display. Each plot display is based on the current analysis results. Plots are updated as new results are acquired.

To select a plot type for display in the plot window, click on the tab of the plot window. From the drop--down menu, use the Plot menu to select a plot from the plot categories (Jitter, Noise, Eyes).

, (single plot, two plots, or four

Examining Plots

You can examine plots in greater detail by either double--clicking in the plot window or selecting Examine… from the drop--down list in the plot window. Either of these actions launches a Matlab plot window which provides advanced tools to examine graphical displays of data.

Adapted From the 80SJNB Online Help

Operating Basics

Plot Type Definitions

Copying Plot Images

Plot types are divided into the following categories:

H Jitter: See Jitter Plots for a list of the types of jitter plots and their descrip-

tions.

H Noise: See Noise Plots for a list of the types of noise plots and their

descriptions.

H Eyes: See Eye Plots for a list of the types of eye plots and their descriptions.

You can copy the plot image displayed in any one of the plot windows. The copy is placed in the Windows clipboard so it can be used to paste into other Windows programs. This is convenient for creating reports and engineering records to share with others.

To create an image file of a plot, follow these steps:

1. Touch the mouse attached to the instrument, right--click anywhere within the plot window of the plot you intend to copy.)

2. Select Copy Image from the drop--down list. This copies the image to the Windows clipboard.

area of the plot window of the plot you copy. (If using a

3. Open your destination program (such as WordPad or Paint) and paste the image into the application.

Exporting Plot Data

Adapted From the 80SJNB Online Help

There are two ways to export plot information from the 80SJNB application for use in other applications:

H You can export the numerical data that is represented in the plot figure. This

may be useful for performing additional data processing.

H You can create an image file that captures the current plot view. This is a

useful way to document your results.

The application offers the following choices from the drop--down list (right-mouse click over the selected plot).

Operating Basics

H Plot lets you select a different plot to display in the window. The window

displays the new plot based on the acquired data.

H Examine… opens a Matlab plot window which provides additional tools to

more closely examine plot characteristics.

H Copy Image saves the contents of the plot window as an image file.

H Export… saves the numerical values from the plot window in text or

MATLAB format.

NOTE. Export plot functions are disabled whenever the application is actively sequencing.

Exporting Raw Plot Data

The 80SJNB provides two methods to export the raw plot data.

H Export Waveform…. accessed from the File menu, exports the underlying

waveform correlated pattern data used for processing.

H Export… accessed from the plot window, exports the data used to create the

plot image.

NOTE. The 80SJNB application can produce files that are too large for some spreadsheet programs to load completely . However, you can use a text editor to view the entire file.

Export Waveform

To export the waveform data used for processing, follow these steps:

1. Select File > Export Waveform… to display the Export Data dialog box.

Adapted From the 80SJNB Online Help

Operating Basics

2. Select the directory where you would like to save the data and name the file.

By default, the selection list defaults to the filename “data”, and offers to place the data in the My Documents folder. The default data type is Comma Separated Values (.csv).

If you have a keyboard attached, you can change the filename.

3. Use the drop--down list for Data Format and select the file type. The choices are:

H Comma Separated Values (.csv) – ASCII text that can be loaded into a

spreadsheet.

H ASCII Text (.txt) – ASCII text that is readable by an editor such as W ordPad.

H MATLAB (.mat) – Binary data in the native MATLAB 7.0 format.

Adapted From the 80SJNB Online Help

Binary files typically use about 40% more disk space as text files.

Operating Basics

Export

To export the numeric data used to create a specific plot, follow these steps:

1. Touch the using a mouse attached to the instrument, right--click anywhere within the plot window of the plot you intend to export.)

2. Select Export… from the drop--down menu.

3. Use the Export Data dialog box to select the directory where you would like

to save the data and name the file.

By default, the selection list defaults to the filename “data”, and offers to place the data in the My Documents folder. The default data type is Comma Separated Values (.csv).

If you have a keyboard attached, you can change the filename.

area of the plot window of the plot you want to export. (If

4. Use the drop--down list Data Format to select the file type. The choices are:

H Comma Separated Values (.csv) – ASCII text that can be loaded into a

spreadsheet.

H ASCII Text (.txt) – ASCII text that is readable by an editor such as W ordPad.

H MATLAB (.mat) – Binary data in the native MATLAB 7.0 format.

Binary files typically use about 40% more disk space as text files.

Adapted From the 80SJNB Online Help

Plot Types

Operating Basics

NOTE. Files with .txt and .csv extensions are identical except for the extension.

Jitter Plots

Jitter Plots Description

DDJ vs Bit Data Dependent Jitter vers us Bit displays the deviation of edge crossings at the

user--specified Decision Threshold for each bit of the entire pattern. The pattern itself is shown in the background for cross reference. If the pattern is very long, the bits will be visible only when opening the graph with Examine…

DDJ PDF Data Dependent Jitter Probability Density Function is the histogram of the data pattern

correlated jitter, including Duty Cycle Distortion. The PDF is composed of the crossing deviations at the user specified Decision Thres hold of all edges of the data patt ern.

DDJ Spectrum The Data Dependent Jitter Spectrum is the result of the time domain to frequency domain

transformation of the series of crossing dev iations of data pattern edges at the user specified Decision Threshold.

RJ PDF Random Jitter Probability Density Function shows the Gaussian distribution of the random,

unbounded, uncorrelated jitter component. It is computed from data acquired on a single edge of the bit stream.

PJ PDF Periodic Jitter Probability Density Function represents the histogram of the uncorrelated,

bounded, periodic jitter component. It is computed by spectral separation of the jitter data acquired on a single edge of the bit stream.

RJ Spectrum Random and Periodic Jitter Spectrum represents the spectral distribution of the uncorrelated

jitter acquired on a single edge. The spurs represent the periodic jitter spectral lines, and the rest of the evenly distributed spectral lines compose the random jitter spectrum.

RJ*PJ PDF Random Jitter and Periodic Jitter Probability Density Function is the histogram of the

uncorrelated jitter data acquired on a single edge of the pattern.

DJ PDF Deterministic Jitter Probabilit y Densit y Funct ion shows the distribution of the bounded jitter

component. The histogram is computed by convolving the DDJ PDF with the PJ PDF.

TJ PDF Total Jitter Probability Density Function represents the computed histogram derived from all

jitter components, correlated and uncorrelated, bounded and unbounded. The convolution of DJ PDF and RJ PDF yields the Total Jitter histogram.

BER Bathtub The BER Bathtub curve is computed as a horizontal slice of the 3-- dimensional BER Eye at

the Decision Threshold. It represents the ex trapolated total jitter and horizontal eye opening limits at projected bit error rates.

Q Bathtub The Q--scaled curve is a linearized scale version of the BER Batht ub curve. It represents the

extrapolated total jitter and horizontal eye opening limits at projected bit error rates.

Eye Plots

Eye Plots Description

Correlated Eye The Correlated Eye is a color graded eye pattern built by folding the correlated pattern at clock

PDF Eye The PDF Eye is a color graded Probability Density Function representing the eye pattern,

Adapted From the 80SJNB Online Help

rates. The correlated pattern is computed from the acquired full length data pattern by filtering out the uncorrelated components.

constructed from the convolution of the Correlated Eye with uncorrelated jitter and noise probability distributions.

Operating Basics

Eye Plots Description

BER Eye The BER Eye is a three--dimensional color graded map representing the predicted bit error

rates at all decision thresholds and sampling phases in the unit bit interval.

QEye The Q Eye is a three--dimensional color graded map representing the predicted bit error rates

at all decision thresholds and sampling phases in the unit bit interval with a linearized Q-- scale, rather than the BER logarithmic scale.

BER Contour The BER Contours show the boundaries of the eye opening at the projected bit error levels.

Noise Plots

Noise Plots Description

DDN vs Bit Data Dependent Noise versus Bit displays the data levels sampled at the user specified

Sampling Phase through the entire pattern. The pattern itself is shown in the background for cross reference. If the pattern is very long, the pattern bits will be visible only when opening the graph with Examine…

DDN PDF Data Dependent Noise Probability Density Function is the histogram of the data pattern

correlated noise distribution on both logic levels 1 and 0. It includes the data levels at all user specified unit bit interval Sampling Phase.

DDN Spectrum The Data Dependent Noise Spectrum is the result of the time domain to frequency domain

transformation of the series of level samples taken on all bits at the user specified Sampling Phase of the unit bit interval.

RN PDF Random Noise Probability Density Function shows the Gaussian distribution of the random,

unbounded, uncorrelated noise component. It is computed from data acquired on a single flat spot of logic level 1 of the bit stream.

PN PDF Periodic Noise Probability Density Function represents the histogram of t he uncorrelated,

bounded, periodic noise component. It is computed by spectral separation of the noise data acquired on a single flat spot of logic level 1 of the data st ream.

RN*PN Spectrum Random and Periodic Noise Spectrum represents the spectral distribution of the uncorrelated

noise acquired on a single flat spot of logic level 1. The spurs represent the periodic noise spectral lines, and the rest of the evenly distributed spectral lines compose the random noise spectrum.

RN*PN PDF Random and Periodic Noise Probability Density Function is the histogram of the uncorrelated

noise distribution on data acquired on a single flat spot of logic level 1 of the bit stream.

DN PDF Deterministic Nois e Probability Density Function shows the distribution of the bounded noise

component. The histogram is computed by convolving the DDN PDF with the PN PDF.

TN PDF Total Noise Probability Density Function represents the computed histogram derived from all

noise components, correlated and uncorrelated, bounded and unbounded. The convolution of DN PDF and RN PDF yields the Total Noise histogram.

BER Bathtub The BER Bathtub curve is computed as a vertical slice of the 3--dimensional BER Eye at the

user specified unit bit interval Sampling Phase. It represents the extrapolated total noise and vertical eye opening limits at projected bit error rates.

Q Bathtub The Q--scaled curve is a linearized scale version of the BER Batht ub curves. It represents

the extrapolated total noise and vertic al eye opening limits at projec ted bit error rates.

Adapted From the 80SJNB Online Help

Parameters

User Settings

These topics list the 80SJNB application parameters and include the menu default settings. You should refer to the documentation for your oscilloscope for operating details of oscilloscope controls, such as front--panel buttons.

The parameter tables list the selections and startup values for each option.

Refer to the GPIB topics for a list of the GPIB Command Syntax along with the arguments, variables, and variable values that correspond to the 80SJNB parameters.

This table lists the default values of the User Settings when the 80SJNB application is first started. If you change these settings, they remain in effect for all successive sessions of the application.

Control Startup Settings

Decision Threshold Normalized

50%

Time Unit Seconds

Sampling Phase Unit Intervals

0UI

Measurement BER 1E--12

Configuration Settings

This table lists the default status of the Configuration Settings when the 80SJNB application is first started. If you change these settings, they remain in effect for all successive sessions of the application.

Control Startup Settings

Source First valid input channel

Difference Waveform

Positive First valid input channel

Negative blank

Turn off all other channels On

Data Pattern

Rate User defined

Pattern Length User defined

Adapted From the 80SJNB Online Help

Parameters

Control Startup Settings

Pattern Sync

Source First channel with a PatternSync Trigger

module

Data:Clock Ratio 1:1

Optical Signal Conditioning

Filter None

Bandwidth blank

Clock Recovery

Source First channel containing a module with clock

recovery

Rate None

Phase Reference

Source None

Frequency blank

Adapted From the 80SJNB Online Help

GPIB

Program Example

You can use remote GPIB commands to communicate with the 80SJNB application. Your GPIB program should comply with the following guidelines:

H The application startup must complete before sending additional GPIB

commands to the application. Querying the variable application returns “80SJNB” when the application startup is complete.

H The measurements cycle must complete before you query data. Querying the

variable DataReady returns “True” when the data is ready.

The program example shows how to communicate with the 80SJNB application using VARIABLE:VALUE remote GPIB commands. The program includes the following steps:

1. Starting the application.

2. Configuration and setting analysis state variables.

GPIB Commands

GPIB Reference Materials

Starting and Setting Up

the Application Using

GPIB

3. Starting and checking the state of the acquisition and processing cycle.

4. Check for errors.

5. Query measurement results.

6. Export data.

To use GPIB commands with your oscilloscope, you can refer to the following materials:

H The GPIB Program Example topic for guidelines to use while designing a

GPIB program.

H The online Programmer Guide for the CSA8000 and TDS8000 instruments.

To start the 80SJNB application, you must send the oscilloscope the following GPIB command:

APPlication:ACTivate ”80SJNB”

Adapted From the 80SJNB Online Help

GPIB

The application uses the GPIB VARIABLE:VALUE command with arguments to control execution and return status of the 80SJNB.

Variable:Value Command

The VARIABLE:VALUE command accepts string arguments for a control or data variable and a value to which to set the argument.

Syntax

To set a variable to a value:

NOTE. The arguments <variable name> and <variable value> are required in the order indicated with no spaces allowed.

To query the value in a variable:

VARIABLE:VALUE ”<Variable Name>”,”<Variable Value>”

VARIABLE:VALUE? <variable name>

CAUTION. Commands are case and space sensitive. Your program will not operate correctly if you do not follow the capitalization and spacing precisely.

Variable:Value Command

Arguments and Queries 1

Name Valu e Function Query form

Application Exit Exits the application. Done

SequencerState {Run|Pause|Stop} Sets or returns the Measurement Sequencing

SequencerMode {SingleSequence, FreeRun} Sets the sequencer mode; startup default is

DataSource {CH1|CH2|CH3|CH4|CH5|CH6|CH7|CH8

|MATH1|MATH2|MATH3|MATH4|MATH5|MATH6 |MATH7|MATH8}

ScopeSync Autosyncs the signal source, data pattern rate,

DecisionThresholdAbs Any valid floating point value Sets or returns the absolute decision threshold

DecisionThresholdPct Any valid floating point value between 0.0 and 1.0

inclusive.

or the Stop Sequencing command.

Free Run.

Sets or returns the data source.

Note: Math expressions must be programmed

through the CSA/TDS8000 Series instrument GPIB interface commands.

data pattern length, and data:clock ratio to the signal applied to the oscilloscope.

value.

Sets or returns the normalized decision threshold value.

returns …

Running, Paused, Stopped

Sequencer mode

Current value.

Adapted From the 80SJNB Online Help

GPIB

Name Query form

DecisionThresholdUnits {Absolute, Normalized} Sets or returns the desired decision threshold

SamplingPhaseAbs Any valid floating point value. Sets or returns the absolute sampling point

SamplingPhase Any valid floating point value between 0.0 and 1.0

inclusive.

SamplingPhaseUnits {Absolute, Normalized} Sets or returns the desired sampling point

PatternLength Any positive real integer value. Sets or returns the data pattern length in bits. Current value.

DataClockRatio Accepts a ratio of

1:8 to 1:1 or 1:1 to 128:1.

DataRate {FC266|FC266E| OC9|FC531|FC531E| OC12|OC18

|FC1063E|FC1063|OC24|ENET1250|OC36|FC2125 |OC48|ENET2500|INFIniband|FEC2666|ENET3125 |XAUINEAR|XAUIFAR|FC4250|ENET9953|OC192 |ENET10313|FC10519|FEC10664|FEC10709|ENET1109 |OC768|FEC42657|FEC43018}

Any valid positive floating point value or communication standard.

FunctionValu e

value to use. By setting the units to Absolute, the DecisionThresholdAbs value is used. If the units are set to Normalized, the decision threshold is calculated based on waveform data according to the DecisionThresholdPct normalized value.

value.

Sets or returns the normalized sampling point value.

value to use. By setting the units to Absolute, the SamplingPhaseAbs value is used. If the units are set to Normalized, the sampling point is calculated based on waveform dat a according to the SamplingPhase normalized value.

Sets or returns the data pattern Data:Clock ratio.

Sets or returns the expected data rate. Communication st an-

returns …

Current value.

dard or current value.

Variable:Value Command

Arguments and Queries 2

Name Valu e Function Query form returns

BER Any valid floating point value between 1e--3 and 1e--24

inclusive.

TimeUnits {S|UI} Sets or returns the units for the time

PhaseReferenceSource {C1C2 --or-- C1_C2,

C3C4 --or-- C3_C4, C5C6 --or-- C5_C6, C7C8 --or-- C7_C8}

PhaseReferenceFrequency Any valid phase reference frequency as defined by the

selected phase reference source module.

PatternSyncSource {CH1|CH2|CH3|CH4|

CH5|CH6|CH7|CH8| TRIGPROBE}

ClockRecoverySource {CH1|CH2|CH3|CH4|

CH5|CH6|CH7|CH8}

ClockRecoveryRate Valid values include any communication standard token

for communication standards supported by the c lock recovery module or a positive floating point value if the clock recovery unit supports user rates.

Sets or returns the current BER value. Current value.

scale.

Sets or returns the phase reference source module.

Sets or returns the phase reference frequency.

Sets or returns the pattern sync source channel.

Sets or returns the clock recovery source. Current value.

Sets or returns the clock recovery rate. Current value.

Adapted From the 80SJNB Online Help

…

S, UI

Current value.

CH1, CH2, CH3, CH4, CH5, CH6, CH7, CH8

GPIB

Name Query form returns

DataReady {True, False} Sets or returns a value indicating if sequencing

NegativeDataSource {CH1|CH2|CH3|CH4|

CH5|CH6|CH7|CH8}

FunctionValu e

is complete and data is ready to be read.

Note: Setting this value to False before beginning a sequence prevents accidentally reading the DataReady value from a previous sequence before it is reset by the application.

Sets or returns the negative data source used for differential math waveform.

…

True, False

Current value.

Variable:Value Command

Arguments and Queries 3

Name Valu e Function Query form returns

SaveFilename <filename>

RecallFilename <filename>

Setup Recall|Save|Default Performs the Save/Recall/Default setup action DONE, ERROR

ExportFormat {CSV, MAT} Sets or returns the current plot diagram export

ExportType {CORRWFM|RJPDF|PJPDF|RJPJPDF|RJPJSPEC

ExportFilename <filename>

ExportCurve {GO} Sets or returns the export action. DONE, ERROR

ErrorMessage Returns the last error message. Current value.

<filename> is a string of from 1 to 40 characters that are valid for filen ames according to Windows file system standards.

|DDJPDF|DJPDF|DDJSPEC|TJPDF|H BATH|QHBATH |RNPDF|PNPDF|RNPNPDF|RNPNSPEC|DDNPDF |DNPDF|DDNSPEC|TNPDF|VBATH|QVBATH |CORREYE|PDFEYE|BEREYE|QEYE}

Sets the filename used when saving setup files.

Specifies the name of the file when recalling a setup.

format.

Sets or returns the type of export to perform. Current value.

Sets the filename used when exporting data.

…

Error is returned if unsuccessful.

Current value.

Error is returned is export is unsuccessful.

Adapted From the 80SJNB Online Help

Measurements Results Queries

GPIB

Variable:Value Results

Queries

These values, when used with the Variable:Value command, return the results for the individual measurement results.

Valu e Function

DJ Returns the measured Deterministic Jitter.

DDJ Returns the Data Dependant Jitter.

DCD Returns the Duty Cycle Distortion.

RJ Returns the measured Random Jitter (RMS).

RJH Returns the Horizontal component of random jitter (RMS).

RJV Returns the Vertical component of random jitter induced by noise converted to jitter through an

average slew rate (RMS).

PJ Returns the measured Periodic Jitter (peak-- to--peak).

PJH Returns the Horizontal component of periodic jitter (peak--to--peak).

PJV Returns the Vertical component of periodic jitter (peak--to--peak) induced by noise converted to

jitter through an average slew rate.

TJ Returns the Total Jitter at user--specified BER.

EOH Returns the Horizontal Eye Opening at user specified BER.

RJDD Returns the Random Jitter computed in the Dual Dirac model.

DJDD Returns the Deterministic Jitter computed in the Dual Dirac model.

DN Returns the Measured Deterministic Noise.

DDN Returns the Data Dependant Noise.

DDN1 Returns the Data Dependant Noise on logical level 1.

DDN0 Returns the Data Dependant Noise on logical level 0.

RN Returns the measured Random Noise.

RNV Returns the Vertical component of random noise.

RNH Returns the Horizontal component of random noise induced by jitter converted to noise through

an average slew rate.

PN Returns the measured Periodic Noise.

PNH Returns the Horizontal component of periodic noise (peak-- to--peak) induced by jitter converted

to noise through an average slew rate.

PNV Returns the Vertical component of periodic noise (peak--to--peak).

TN Returns the Total Noise at user--specified BER.

EOV Returns the Eye Opening at user--specified BER.

EA Returns the amplitude of the eye computed as the mean--to--mean of logical 1 and logical 0 bit

levels sampled at the user defined Sampling Phase.

Adapted From the 80SJNB Online Help

GPIB

Error Messages

GPIB Commands Error

Codes

Error

Description

Code

-- 1 Unknown error code

1 The channel does not support bandwidth

2 Phase characterization failed

3 No data to export

4 Not allowed to change setting while sequencing

5 Invalid value

6 Argument cannot be null

7 Value is outside the range of acceptable values

8 Query curve returned no data

9 Unexpected GPIB response

10 No data source selected

11 One or more WfmDBs are enabled, turn them off to continue

12 Trigger failure, check your configuration

13 The pattern is not synchronized or is too small

14 Can’t export the curve

15 Couldn’t analyze edge

16 Histogram testing is enabled; turn it off to continue

17 Mask testing is enabled; turn it off t o continue

18 One or more measurements are enabled; turn them off to continue

19 Waveforms other than 80SJNB signal source are enabled; turn them off to continue

20 Save setup failed

21 Recall setup failed

Adapted From the 80SJNB Online Help

GPIB Program Example

GPIB

The following sequence of commands demonstrates the GPIB commands used to configure and operate the 80SJNB jitter analysis application. All commands are sent to the instrument which hosts the programmable interface for the 80SJNB.

NOTE. All words within quotes are case sensitive and must be entered exactly as shown, including spaces and quotes.

1. Send the command to start the 80SJNB application.

APPLICATION:ACTIVATE ”80SJNB”

2. Set the signal source channel, data rate, pattern length, and data--to--clock ratio to be analyzed.

VARIABLE:VALUE ”DataSource”,”C1”

VARIABLE:VALUE ”DataRate”,”10.3125e9”

VARIABLE:VALUE ”PatternLength”,”32767”

VARIABLE:VALUE ”DataClockRatio”,”1:1”

3. Set the following variables before starting the analysis. The application updates these values to signal the application’s analysis state.

VARIABLE:VALUE ”DataReady”,”False”

VARIABLE:VALUE ”ErrorCode”,””

4. Start the acquisition and processing cycle.

VARIABLE:VALUE ”SequencerState”,”Run”

5. Check the state of the acquisition and processing cycle.

Query the following variable:

VARIABLE:VALUE? ”DataReady”

When the application has finished acquiring and processing the data, it will set the DataReady value to True.

Check the SequencerState variable to check for errors.

VARIABLE:VALUE? ”SequencerState”

If there is an error, the DataReady variable will not be set to True but the sequencer state will be set to Stop.

Adapted From the 80SJNB Online Help

GPIB

Loop on querying these values (with a time delay so the instrument is not overloaded handling programmable interface queries) until one of them changes.

NOTE. If the SequencerState variable is set to stop and DataReady is not true, this likely indicates an error.

6. Check the ErrorCode variable to see if an error has been reported

VARIABLE:VALUE? ”ErrorCode”

If the ErrorCode value has a numeric value greater than 0, query the ErrorMessage variable to get the corresponding error message:

VARIABLE:VALUE? ”ErrorMessage”

7. If the DataReady variable is set to True (queried in step 3), you can query for measurement results. For example to query the deterministic jitter:

VARIABLE:VALUE? ”DJ”

8. You can also export the plot data. The following commands set the format, data to export, filename, and then exports the data.

VARIABLE:VALUE “ExportFormat”,”CSV”

VARIABLE:VALUE ”ExportType”,”DJPDF”

VARIABLE:VALUE ”ExportFilename”,”C:\My Documents\MyDJPDF.csv”

VARIABLE:VALUE ”ExportCurve”,”GO”

9. Query the ExportCurve variable to determine when the data export has completed:

VARIABLE:VALUE? ”ExportCurve”

The application will set the ExportCurve value to ”Done” when the data has been exported.

Adapted From the 80SJNB Online Help

Application Example

About Application Example

This simplified application example gives you a sample on how to setup and use the application. This may help you when setting up your own test situation.

Requirements:

H TDS/CSA8000B or TDS/CSA8200 series oscilloscope

H 80SJNB Jitter Analysis software

H 80A06 PatternSync Trigger Module

H Optical module with clock recovery

H SMA cables

NOTE. If your oscilloscope setup includes a second monitor, you can select and drag the title bar of the online help window to position it in the second monitor. This allows you to display these application examples in the second monitor, and still view the waveform (or a plot) and the 80SJNB measurement results on the oscilloscope.

Adapted From the 80SJNB Online Help

Application Example

Example

Setup the Oscilloscope

This quick demo demonstrates the TDS/CSA8000 80SJNB Jitter Noise BER application on an Optical signal for fast analysis of BER, Jitter, and Noise.

1. Install the modules and make the signal connections.

2. Turn on the instrument. After startup, perform the following setup steps:

a. Press the Default Setup button on the instrument.

b. Select CH1 on the instrument.

c. Press the SETUP DIALOGS button on the instrument.

d. Set the Horizontal scale to 5 ns.

e. In the Setups dialog box, select the Trig tab.

f. Select Pattern Sync as the trigger source

Adapted From the 80SJNB Online Help

g. Press the Pattern Sync Setup…. button.

Application Example

3. Enter the Data Rate and Pattern Length.

a. Set the Data Rate to 622.08 Mbps.

b. Set the Pattern Length to 127 bits.

c. Close the dialog box.

Adapted From the 80SJNB Online Help

Application Example

Setup the 80SJNB

Application

You should now have a stable signal display. If not, the 80SJNB application may fail to acquire data. Recheck all settings, signal source, and connections.

1. Start the 80SJNB application. With the oscilloscope application displayed, use the Applications menu on the toolbar bar and select the 80SJNB application.

You can also use the Windows desktop shortcut or the Windows Start menu by selecting Start > Programs > Tektronix TDSCSA8000 > 80SJNB > 80SJNB.

2. Wait for the 80SJNB application to finish loading.

3. Display the configuration dialog box by pressing

4. Most of the configuration settings will most likely be filled at this time since it read the oscilloscope configuration. If not, you can press the AutoSync to Selected Waveform button to sync the Source, Data Pattern, and Pattern

Sync settings to the oscilloscope.

Since this is an optical signal and we’re using the clock recovery signal, you’ll need to select the optical signal filter and select the clock recovery settings.

The setup we’re using doesn’t include a Phase Reference module so set this to None.

Adapted From the 80SJNB Online Help

Application Example

Close the dialog box.

5. Press

While the cycle is running, you’ll see the sequence of events displayed at the bottom of the application display. When the cycle is complete, the message “Analysis Complete” is displayed.

to start the acquisition and processing cycle.

Adapted From the 80SJNB Online Help

Application Example

6. Once the cycle is complete, you’ll see the displayed results. The example below shows a four plot display with the summary table of the numerical results.

Working with the Results

1. Press to remove the plot displays and show the detailed table of results.

Adapted From the 80SJNB Online Help

Application Example

2. Redisplay the plot (or plots) by selecting one of the plot display buttons

You can click on the Results tab to minimize the detailed list to summary list.

3. With the plots now redisplayed, click on one of the icons to display the drop--down menu. The menu provides several functions, one of which is to select a different type of plot to display in that window.

Adapted From the 80SJNB Online Help

Application Example

You can select any plot type. The plot will be displayed based on the data based on the results of the last processing cycle.

4. To further examine a plot, you can display any plot in a MatLab window, providing you with more tools to work with the data. Use the

icon and choose Examine…

The plot opens in the new window to provide further data analysis and visualization of the plot displays.

Matlab provides multiple capabilities to display and annotate the plot diagrams, including:

H Pan and Zoom

H 2D and 3D visualization

H Rotation

H Data Cursors

H Color enhancements

Here, the BER Eye plot was selected to examine in a 3D view by using the rotate function.

Adapted From the 80SJNB Online Help

Application Example

Close the window, returning to the 80SJNB display.

This is the end of the example. You can continue on by acquiring new data, displaying various types of plots, and examine the plots with the various tools available.

Adapted From the 80SJNB Online Help

Application Example

Adapted From the 80SJNB Online Help

Algorithms

About Measurement Algorithms

Tektronix has developed a white paper detailing the algorithms used by the 80SJNB application to make the measurements.

Go to the Tektronix web site to view the white papers.

www.tektronix.com

At the Tektronix home page, select oscilloscopes > sampling

Test Methodology

The application performs the measurement according to the following steps:

1. Configures the oscilloscope and jitter application according to the Configuration settings and User settings.

2. Performs an Autoset.

3. Scans part of the pattern.

4. Analyzes the edge.

5. Acquires the jitter data.

6. Acquires the noise data.

7. Scans the full pattern.

8. Analyzes the acquired data.

9. Displays the results as statistics. You can also log the results or data points to

a .csv file.

10. Displays the plots if selected.

Adapted From the 80SJNB Online Help

Algorithms

Adapted From the 80SJNB Online Help

Correlations

Correlation to Real- Time Oscilloscope Jitter Measurements

The 80SJNB Advanced Jitter, Noise, and BER Analysis application is designed to make measurements in companion with the CSA8000 and TDS8000 Series Sampling Oscilloscopes.

The methodology to make these measurements on a sampling oscilloscope is quite different than the methodology to make similar measurements on a real--time oscilloscope.

Tektronix has developed a white paper that provides a correlation of measurements between the 80SJNB application and the TDSJIT3 application.

Go to the Tektronix web site to view the white papers.

www.tektronix.com

At the Tektronix home page, select oscilloscopes > sampling

You can download a pdf of the white paper titled:

80SJNB Jitter Measurement Results Correlation

Adapted From the 80SJNB Online Help

Correlations

Adapted From the 80SJNB Online Help

Index

Symbols

.BMP File, 7 .CSV File, 7 .JPG File, 7 .MAT File, 7 .PNG File, 7 .TXT File, 7

Numbers

80SJNB, iii, 12, 35

Product Description, iii start, 35 Toolbar, 12

80SJNB application, 6, 35

Directory Structure, 6

80SJNB application description, 1

About, 9, 35

GPIB Program, 35

User Interface, 9 About Operating Basics, 5 Accessories, 1 Acquiring Data, 22 Acquistion, 7

Iinterrupt, 7

Pausing, 7 Analysis Setup, 15 Application, 6, 11, 35

Exiting, 6

File Name Extensions, 7

GPIB Commands, 35

Method Used to Perform Measurements, 53

Minimizing and Maximizing, 6

Navigating, 11

Returning to Oscilloscope, 5

Tektronix 80SJNB Online User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Contacting Tektronix

Preface

Welcome to the Jitter, Noise, and BER Analysis Software

Related Documentation

GPIB Information

Relevant Web Sites

Conventions

Types of Online Help Information

Using Online Help

Feedback

Getting Started

Product Description

Requirements and Restrictions

Accessories

Connecting to a Device Under Test (DUT)

Deskewing Probes and Channels

The Importance of Jitter and Noise Separation

Operating Basics

General Information

Exiting the Application

File Name Extensions

File Menus

Oscilloscope Settings

About the Results

Clearing Results

About Plotting

Navigating the User Interface

Windows User Interface

Setting up the Application for Analysis

Configuring Sources

Configuring User Settings

About Measurements

Acquiring Data

Saving and Recalling Setup Files

Saving a Setup File

Working with Numeric Results

Working with Plots

Examining Plots

Plot Type Definitions

Copying Plot Images

Exporting Plot Data

Plot Types

Parameters

User Settings

Configuration Settings

GPIB

Program Example

GPIB Commands

Variable:Value Command

Measurements Results Queries

Error Messages

GPIB Program Example

Application Example

About Application Example

Example

Algorithms

About Measurement Algorithms

Test Methodology

Correlations

Correlation to Real- Time Oscilloscope Jitter Measurements

Index