Copyright: ©Tektronix, Inc.
Citation: Excerpt of RT-Eye Online Help.


Copyright

Copyright © Tektronix. All rights reserved. Licensed software products are owned by Tektronix or its suppliers and are protected by United States 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.

RT-Eye Serial Data Compliance and Analysis Online Help, 076-0059-00, Version 3.0.0.

Contacting Tektronix:

Tektronix, Inc.

14200 SW Karl Braun Drive or P.O. Box 500

Beaverton, OR 97077 USA

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

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

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


General Safety Summary

Review the following safety precautions to avoid injury and prevent damage to this product or any products connected to it. To avoid potential hazards, use this product only as specified.

Only qualified personnel should perform service procedures.

While using this product, you may need to access other parts of the system. Read the General Safety Summary in other system manuals for warnings and cautions related to operating the system.

To Avoid Fire or Personal Injury:

Connect and Disconnect Properly: Do not connect or disconnect probes or test leads while they are connected to a voltage source.

Observe All Terminal Ratings: To avoid fire or shock hazard, observe all ratings and markings on the product. Consult the product manual for further ratings information before making connections to the product.

Do Not Operate With Suspected Failures: If you suspect there is damage to this product, have it inspected by qualified service personnel.

Symbols and Terms: The following terms and symbols may appear in the online help.

 WARNING: Warning statements identify conditions or practices that could result in injury or loss of life.

 CAUTION: Caution statements identify conditions or practices that could result in damage to this product or other property.

Terms on the Product: The following terms may appear on the product:

DANGER indicates an injury hazard immediately accessible as you read the marking.

WARNING indicates an injury hazard not immediately accessible as you read the marking.

CAUTION indicates a hazard to property including the product.

Symbols on the Product: The following symbol may appear in the product:

CAUTION Refer to Help


Welcome to the RT-Eye Serial Compliance and Analysis Application
Welcome to the RT-Eye™ Serial Compliance and Analysis Application

The RT-Eye product is an application that enhances the basic capabilities of some

high-performance oscilloscopes from Tektronix. The application incorporates MATLAB run-time and uses it to display real-time graphical representations of the measurement results in plot windows.

The Real-Time Eye (RT-Eye) application provides general compliance measurements and analysis capabilities for emerging serial data standards, and includes the following features:

•	Selects and configures multiple measurements on one differential or two single-ended probe inputs

•	Performs Timing, Amplitude, and Jitter measurements per industry standard methods

•	Displays an RT-Eye rendering of the serial bit stream, and other plots such as Waveform (with Bit Error Locator), Jitter Histogram, Jitter Spectrum, and Jitter Eye Opening analysis

•	Specifies configurable Limits for Pass/Fail analysis on waveforms and measurements when a Limits file is enabled

•	Performs "Plug-Fest" level compliance measurements defined by industry working groups using optional Compliance Modules such as Fully Buffered DIMM (FB-DIMM), InfiniBand, PCI Express, SAS, and Serial ATA.

•	Exports analysis results to a .csv file for further analysis

•	Tracks and saves the worst case waveforms to .wfm files

•	Creates, formats, and generates reports

•	Automates compliance tests for production

What do you want to do?

Study online help

Read the product description

Learn more about application installation

 To return to the Table of Contents, select Help Topics from the Help menu bar.


5-Time Free Trial
Five-Time Free Trial

A five-time free trial is available for all applications in the "Applications on this CD and Compatible Oscilloscope" table found in the Optional Applications Software on a Windows-Based Oscilloscope Installation Manual. You can start and exit an application up to five times to help you evaluate Tektronix software solutions.

Note: To evaluate an application, first check that your TDS6000- or TDS/CSA7000-series oscilloscope firmware version is consistent with the version requirements mentioned in the application’s readme file. You can check the firmware version number from the oscilloscope Help drop-down list (About …). You can check the application’s firmware compatibility by referring to the System Requirements section in the application’s readme.txt file.

If an application becomes available after you receive your oscilloscope, you can download the application as described in the installation manual (Tektronix part number 071-1078-xx) to obtain the free trial.


Related Documentation

In addition to the online help, the application includes a Reference guide. Refer to the

RT-Eye™ Serial Compliance and Analysis Quick Start User Manual (071-1769-xx) for the following information:

•	The manual provides task-oriented procedures to explain the basic operations that cover the set up of the application.

Refer to the Optional Applications Software on a Windows-Based Oscilloscope Installation Manual for the following information:

•	Software warranty

•	List of all available applications, compatible oscilloscopes, and relevant software and firmware version numbers

•	Applying a new label

•	Installing an application

•	Enabling an application

•	Downloading updates from the Tektronix Web site

Note: You can view a PDF file of the installation manual from the CD Installation Browser and from the Documents directory on the Optional Applications Software on a Windows-Based Oscilloscope CD-ROM.

See also:

GPIB Information

Relevant Web Sites

Application CD Contents

Access to PDF Files

Types of Online Help Information

Using Online Help


GPIB Information

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

•	This online help provides a sample RT-Eye program that illustrates how to set up and use remote automation

•	The user manual for your oscilloscope provides general information on how to operate the oscilloscope

•	The online help for your oscilloscope can provide details on how to use GPIB commands to control the oscilloscope if you install the GPIB Programmer guide (and code examples) from the oscilloscope CD-ROM

•	The online help for Option SST Serial ATA and Serial Attached SCSI Analysis module provides details on how to use GPIB commands for SAS and SATA

See also:

About the GPIB Program


Relevant Web Sites

You can also find useful information on serial data standards on the following Web sites:

•	www.Infinibandta.org

•	www.pcisig.com

•	www.T11.org

•	www.tektronix.com/search RT-Eye.


Application CD Contents

The Optional Applications Software on a Windows-Based Oscilloscope CD-ROM includes files for the following types of documentation:

•	Printable file of the RT-Eye Serial Data Compliance and Analysis online help formatted to resemble a user manual

•	Printable file of the Option SST online help formatted to resemble a user manual

•	Printable file of the Report Generator online help formatted to resemble a user manual

•	PDF files of the Methods of Implementation (MOI) for serial data standards as they apply to the corresponding compliance modules

•	RT-Eye™ Serial Compliance and Analysis Quick Start User Manual (071-1769-xx)

•	Optional Applications Installation manual

See also:

Access to PDF Files


Access to PDF Files

You can use any of the following methods to view the various PDF files associated with this application:

•	Access a file in the Documents directory on the Applications CD from any PC.

•	Access documents on the CD from the Installation Browser.

•	Note: The documents are available on Application CD at Documents\TDSRT-Eye. The CD Installation Browser page for TDSRT-Eye is accessed from "Serial Data Compliance and Analysis" and also includes a link to "Browse the Documentation". This link opens a Microsoft Explorer Window to the folder above.

•	Select a file from the Start menu in the oscilloscope task bar; you may need to first minimize the RT-Eye application

•	Access a file from the Help drop-down list in the RT-Eye application

Note: If you do not have an Acrobat reader to view a PDF file, you can get a free copy of the reader from the www.adobe.com/products/acrobat Web page.


Conventions

Online help topics use the following conventions:

•	The terms "RT-Eye application" and "application" refer to the RT-Eye Serial Compliance and Analysis Application.

•	The term "oscilloscope" refers to any product on which this application runs.

•	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.

•	The term "Compliance Module" refers to optional "plug-in applications" from Tektronix used for compliance testing to specific serial data standards.

•	The term "Limits Module" refers to a formatted text file used to specify user limits on mask geometry and measurement boundary conditions for Pass/Fail testing.

•	The term "channel" is context dependent. It can refer to the transmit channel of the device under test or to an oscilloscope channel.

•	The term "DUT" is an abbreviation for Device Under Test.

•	There may be minor differences in the display of user interface screen graphics on other types of oscilloscopes such as TDS6000 or TDS7000.

•	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.


Types of Online Help Information

The online help contains the following types of information:

•	A Getting Started group of topics briefly describes the application, contains connection procedures, and includes an optional deskew procedure.

•	An Operating Basics group of topics covers basic operating principles of the application. The sequence of topics reflects the steps you perform to operate the application and includes definitions for all menus and options.

•	A Tutorial group of topics teaches you how to set up the application to acquire a waveform, take a measurement, view the results, view a plot, and save data to a file.

•	A Serial Analysis Laboratory group of topics demonstrates how to use serial analysis measurements to identify a problem with a serial data waveform through the process of elimination. This should give you ideas on how to solve your own measurement problems.

•	A Reference group of topics includes the parameters (range of values) for all options and the default values.

•	A Measurement Algorithms group of topics includes information on measurement guidelines and on how the application calculates each measurement.

•	A GPIB Command Syntax group of topics contains a list of arguments and values that you can use with the remote commands and their associated parameters. The application includes a simple remote interface program to show you how to operate the application using GPIB commands.

The application Help drop-down list includes a PDF Help menu item you can use to access a PDF file of the help topics. The file is printable and is formatted to resemble a user manual.

The Report Generator utility also has an independent online help system that you can launch from the Report Generator window.

See also:

Using Online Help

Online Help for the Report Generator


Using Online Help

Online help has many advantages over a printed manual because of advanced search capabilities. You can select Help> Topics on the right side of the application menu bar to display the Help file.

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:

•	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.

•	Index tab - enables you to scroll a list of alphabetical keywords. Select the topic of interest to display the corresponding help page.

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

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

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

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

3.	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. Refer to the Find Tab and Searches topic for more information.

•	To print a topic, select the Print button from the help topics menu bar.

•	Select Options from the menu bar for other commands, such as to annotate a topic, to keep the help window on top, or to use system colors.

•	Select the Back button to return to the previous help window. Sometimes you can jump from one topic to another through a hyperlink. If the Back button is grayed out, or a jump is not available, choose the Help Topics button to return to the originating help folder.

•	Browse buttons (Next >> and Previous <<) allow you to move forward and backward through topics in the order of the Table of Contents (TOC).

•	A Note: in the topic text indicates important information.

Note: Green-underlined text indicates a Jump (hyperlink) to another topic. Select the green text to jump to the related topic. For example, select the green text to jump to the topic on Feedback to contact Tektronix.

 You can tell when the cursor is over an active hyperlink (button, jump, or popup), because the arrow cursor changes to a small pointing hand cursor.

The light bulb icon and word Tip indicate additional information to help you operate the application more efficiently.

See also:

Types of Online Help Information


Online Help for the Report Generator

The Report Generator utility is a separate program that allows you to create a new test template or report layout, or edit an existing one. The online help for the Report Generator explains how to use the utility.

See also:

About Generating a Report

Starting the Report Generator and Accessing the Online Help


Online Help for Compliance Modules

Each compliance module has its own help documents: online help or PDF documents called as MOIs (Methods Of Implementation). To view compliance specific help topics, refer to the Help menu in the module of interest.


Find Tab and Searches

Many online help topics contain only tables. To retain vertical and horizontal lines, the tables are graphical objects. The Find tab in the online help does not recognize words in these tables.

The online help is extensively indexed with the proper names of all menus and options as they appear in the application and in the left column of graphical tables.

Note: If you conduct a Find tab search with no results, try the Index tab instead.


Feedback

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 send us your feedback by e-mail to techsupport@tektronix.com, by FAX at (503) 627-5695 (North America), or by telephone (See Contacting Tektronix). Please be as specific as possible and include the following information:

General Information

•	Oscilloscope model number and hardware options, if any

•	Probes used

•	Serial data standard

•	Signaling rate

•	Your name, company, mailing address, phone number, FAX number

Note: Please indicate if you would like to be contacted by Tektronix regarding your suggestion or comments.

Application-Specific Information

•	Software version number

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

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

•	If possible, save the oscilloscope and application setup files from the application to obtain both the oscilloscope .set file and the application .ini file. 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 in the subject line "RT-Eye Problem," and attach the .set, .ini, and .wfm files.

 To include screen shots, from the oscilloscope menu bar, select File> Export. In the Export dialog box, enter a file name with a .bmp extension and select Save. The file is saved in the C:\TekScope\Images directory. You can then attach the file to your email (depending on the capabilities of your email editor).


Product Description

The RT-Eye Serial Compliance and Analysis Application is a software product that enhances basic capabilities of some high-performance oscilloscopes offered by Tektronix. The RT-Eye application is a general analysis tool you can use to test, debug, and verify serial-data based designs. The compliance applications are specific tools you can use with device designs that must comply with serial data standards, such as PCI Express, FB-DIMM, Serial ATA, Serial Attached SCSI, or InfiniBand.

You can use this application to do the following tasks:

•	Select and configure many amplitude and timing measurements on a serial data signal

•	Conduct RT-Eye rendering and mask testing, Time Interval Error analysis, Rj/Dj (random jitter and deterministic jitter) analysis, and display results as a Bathtub plot

•	Locate bit errors (mask violations) on the acquired waveform

•	Display the results as eye diagram, histogram, spectrum, or bathtub curve plots

•	Perform Pass or Fail limits testing based on waveform masks and based on measurements that use Limits Modules

•	Perform "plug-fest" level compliance tests for available compliance modules that test against a specific standard

•	Save the statistical results to a file

•	Save the worst case waveforms to files

•	Generate reports

Note: There are no standard accessories for this product. Refer to Accessories for a list of recommended probes.

What do you want to do?

Check compatibility.

Look over requirements and restrictions.

Install the application.


Analysis and Compliance Modules

You can use the RT-Eye (real-time eye) serial data analysis application and industry specific compliance modules to characterize serial transmission signal integrity. The applications were developed to help you perform analysis on the following types of designs:

•	General serial-data based designs

•	Device designs that need to comply with a specific serial-data standard

The RT-Eye application is the foundation for current and for future compliance modules. Each enabled compliance application shows at least two choices in the Modules drop-down list; one will always be for Serial Analysis.


Compatibility

For information on oscilloscope compatibility, refer to the Optional Application Software on Microsoft Windows Based Oscilloscopes Installation Manual, Tektronix part number 071-1888-xx. The manual is available as a PDF file.


Requirements and Restrictions

The Sun Java Run-Time Environment (JRE) and the Mathworks MATLAB Run-Time Server are components of the RT-Eye application. When you install the application, the InstallShield Wizard automatically installs the proper software components.

MATLAB Server: The MATLAB server is dedicated to the RT-Eye application and cannot be used for other purposes. Do not close the Matlab Server icon [image] in the oscilloscope task bar because this will disrupt the operation of the RT-Eye application. The application will close the MATLAB sever when you exit the application.

Oscilloscope: Maximum sampling rate of 20 GS/s with interpolation is often necessary to ensure accurate results. Be sure to consider the following differences in sampling rates before taking measurements:

•	The TDS6604 oscilloscopes sample at 20 GS/s on two channels and at 10 GS/s on four channels.

•	The TDS7404 oscilloscopes sample at 20 GS/s on one channel and at 10 GS/s on two channels.

•	The TDS6000C oscilloscopes sample at 40 GS/s on two channels and 20 GS/s on four channels.

•	The TDS6000B oscilloscopes sample at 20 GS/s on two and four channels.

•	The TDS7000B oscilloscopes sample at 20 GS/s on one channel, 10 GS/s on two channels, and 5GS/s on four channels.

When the Record Length of the oscilloscope is set to 4M or less, the application can take all measurements. When the Record Length is set to 4M or 20M, the RT-Eye application can take one TIE measurement.

Keyboard: You may need to use a keyboard to enter new names for some file save operations.

Distiller Software: To convert an RTF file from the Report Generator utility to a PDF file, you require distiller software, such as Adobe Acrobat 6.0 or freeware such as CutePDF.


Minimum Required System Configuration

Before operating the RT-Eye application, check the readme.txt file to verify whether the oscilloscope configuration meets the minimum requirements. If the RT-Eye application is installed on the oscilloscope, select Start> Programs> TekApplications> tdsRT-Eye> readme file. If the application is not installed, the readme.txt file is in the same directory as the setup.exe file on the Optional Applications CD.

See also:

Contacting Tektronix


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.

For example, Tektronix recommends that you use the following probes:


Installation

Refer to the Optional Applications Software on a Windows-Based Oscilloscope Installation Manual, Tektronix part number 071-1078-xx, for the following information:

•	Available applications, compatible oscilloscopes, and relevant software and firmware version numbers

•	Using the free trials

•	Applying a new authorized Option Installation key label

•	Installing the application

•	Enabling an application

•	Downloading updates from the Tektronix Web site

The manual is also available as a PDF file.


Connecting to a Device Under Test (DUT)

You can use any compatible probes to connect your DUT (Device Under Test) with your oscilloscope.

There are four typical probing configurations for serial data links: two for Pseudo Differential Waveforms and two for True Differential Waveforms. The method of setting up your measurement channel(s) is dependent on your application and what you want to measure.

 Warning: To avoid electric shock, you must ensure that power is removed from the DUT before attaching probes to it. 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.

See also:

General Safety Summary for the RT-Eye Application

Probe Information

Two TCA-to-SMA Adaptors

One P73XXSMA Differential Probe

Two P72XX Single-Ended or P73XX Differential Probes

One P73XX Differential Probe

Deskewing Probes and Channels


Probe Information

 When you are deciding what oscilloscope and probe combination to use, the system bandwidth should be greater than 1.5 times the bit rate. This provides adequate bandwidth for most of the measurements because most of the energy in high-speed serial data signals is contained in the 1st and 3rd harmonic. To ensure accurate Rise time measurements, 2.5 times the bit rate (5th harmonic) is required.  View an example of the power spectrum of a 2.5 Gb/sec signal.


Power Spectrum of a 2.5 Gb/sec Signal Example

Note: The 1st and 3rd harmonics are the two highest peaks.


Two TCA-to-SMA Adaptors, Diagram A


One P73XXSMA Differential Probe, Diagram B


Two P72XX Single-Ended or P73XX Differential Probes, Diagram C


One P73XX Differential Probe, Diagram D


Deskewing Probes and Channels

When using two channels to perform pseudo-differential measurements, it is important to deskew the probes. Be sure to use the proper deskew fixture and procedure as described in the online help of your oscilloscope.

Note: The RT-Eye application relies on upsampled, deskewed data from the oscilloscope to conduct math operations for differential and common mode waveform measurements. Upsampling prior to deskew is required to ensure accurate measurements.

Oscilloscope firmware V 2.4.0 and above implements sub-sampled deskew and is required if you use the RT-Eye application for Single-Ended measurements.


About Basic Operations

The topics in the Operating Basics book cover the following definitions and tasks:

•	Application user interface

•	Basic oscilloscope functions

•	Saving and recalling

•	Setting up the application

•	Using a Limits file

•	Using User Masks

•	Taking measurements

•	Saving the measurement results

•	Viewing the measurement results as plots

•	Using the plot window zoom and cursors

•	Saving plots

•	Logging the worst case waveforms

•	Creating and generating a custom compliance report

What do you want to do?

•	Start the application

•	Work through the tutorial

•	Work through the Serial Analysis Laboratory

See also:

Analysis and Compliance Modules

Application Directories and Usage

File Name Extensions

About the File Menus

General Steps to Set Up the Application


Starting an Application
Starting the Application

On the oscilloscope menu bar, select File> Run Application> RT-Eye Serial Compliance and Analysis. View how to start the application. For B and C series oscilloscopes, select App> RT-Eye Serial Compliance and Analysis from the menu bar to run the application. For DPO series oscilloscopes, select Analyze> RT-Eye Serial Compliance and Analysis.

The application starts and displays the Measurements> Select menu.

After the application initializes, the Welcome dialog box, if enabled, will appear. If it is disabled, you can use File> Preferences to configure it to appear the next time the application is launched.

You can perform the following functions in this dialog box as shown in the table:


Oscilloscope Menu Bar and Selected Application

For non-B series oscilloscopes, select File> Run Application> RT-Eye Serial Compliance and Analysis to start the application.

For B/C series oscilloscopes, select App> RT-Eye Serial Compliance and Analysis to start the application.


Application Interface

The RT-Eye application uses a Microsoft Windows based interface. Display the definitions of the application user interface items, or view a menu labeled with the user interface items.

Note: The oscilloscope application shrinks to half size and appears in the top half of the screen when the application is running.

See also:

Starting the Application

Hiding the Application

Minimizing and Maximizing the Application

Exiting the Application


Application User Interface Items Definitions
User Interface Definitions

See also:

Menu With Application User Interface Items


Menu With Application User Interface Items


Application Menu Bar and Drop-Down Lists


Using Basic Oscilloscope Functions

You can use oscilloscope controls and functions while running the application. To do so, select a menu from the oscilloscope Menu bar (or Toolbar) and access menus, or use the front-panel knobs and buttons. You can also use the oscilloscope Help menu to access information about the oscilloscope and how to use it.

When you access some oscilloscope controls, the oscilloscope fills the display.

See also:

Returning to the Application

Hiding the Application

Minimizing and Maximizing the Application

Docking the Application

Undocking the Application


Returning to the Application

For B and C series oscilloscopes, select App> Restore Application to return to the RT-Eye application.


Hiding the Application

The Hide function minimizes the application and the oscilloscope fills the display. To hide and return to the application, follow these steps:

1.	Select the [image] command button in the application menu bar.

2.	Use the oscilloscope.

3.	Return to the application.

See also:

Minimizing and Maximizing the Application


Minimizing and Maximizing the Application

To minimize the RT-Eye application, select File> Minimize in the application menu bar.

To maximize the application, select [image] in the task bar.

See also:

Hiding the Application


Exiting the Application

To exit the RT-Eye application, select File> Exit or the [image] (Exit) command button in the application menu bar. When you exit the application, you can choose to keep the oscilloscope setup currently in use with the application or to restore the oscilloscope setup that was present before you started the application.

If you select the Save MyTest check box, the current setup of both the oscilloscope and the application will be saved for convenient recall next time. Refer to MyTest for more information.

See also:

Saving a Setup File

Saving MyTest


Application Directories and Usage
Application Directories

During installation, the application sets up directories for various functions, such as to save setup files, and uses extensions appended to file names to identify the file types.

See also:

Directory Structure for the Serial Analysis Application

File Name Extensions


Directory Structure for the Serial Analysis Application


File Name Extensions


How to Enter Alphanumerical Values

Note: Press the FINE button on the oscilloscope to enter or select the smallest values or units.

Note: Be sure to select the CLR button before you enter a value using the keypad.


Virtual Keypad

Note: Select the [image] icon, and then use the virtual keypad to enter information, such as reference voltage levels.


Virtual Keyboard

Note: Select the [image] icon, and then use the virtual keyboard to enter information, such as file names.


About the File menus

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

Note: The File> Save function saves application settings in an .ini file and the settings of the oscilloscope application in a .set file with a matching name.

If an oscilloscope .set file with a matching name is found when you recall an application setup file, then the oscilloscope settings are also recalled. If the .set file is missing or cannot be opened by the oscilloscope, then the application recalls the application settings and displays a message that the Recall of the .set file failed.

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

See also:

Saving a Setup File

Recalling a Saved Setup File

Recalling the Default Setup


File Menus Definitions
File Menu Definitions


Saving a Setup File

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

1.	Select File> Save. View the Save browser.

The Save dialog box appears. To view details about the file, such as size, type, and modified date, select the Details tool.

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

3.	Select or use the keyboard to enter a new file name.

The application appends an ".ini" extension to the name of the application setup file.

4.	Select the [image] command button.

Note: The application also saves the oscilloscope setup to a ".set" file when you save an application setup. Both the application .ini file and oscilloscope .set file have the same file name.


File: Save Browser

To view details, such as file size, type, and modified date, select the Details tool.


Recalling a Saved Setup File

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

1.	Select File> Recall. View the Recall browser.

The Recall dialog box appears. To view details about the file, such as size, type, and date modified, select the Details tool.

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.

Note: The application recalls the .ini setup file and the associated oscilloscope setup if the application can find a .set file with a matching name.

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

 If a matching .set file is not found or if the .set file does not recall correctly to the oscilloscope, then a warning appears that says the oscilloscope recall failed while the RT-Eye application recall succeeded.

See also:

Recalling a Recently Saved or Accessed Setup File


File: Recall Browser

To view details, such as file size, type, and modified date, select the Details tool.


Recalling the Default Setup

To recall the default application settings, select File> Recall Default.

Note: Most of the settings for the active module are recalled to the default state.


Recalling a Recently Saved or Accessed Setup File

To recall a recently saved or accessed setup file, select File> Recall Recent and then the file from the drop-down list of setup file names.

Note: The application also recalls the associated oscilloscope setup if the application can find a .set file with a matching name.

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

 If a matching .set file is not found or if the .set file does not recall correctly to the oscilloscope, then a warning appears that says that the RT-Eye application recall succeeded but the oscilloscope recall failed.

See also:

Recalling a Saved Setup File


Recall Recent Drop Down List Example
Recall Recent Drop-Down List Example


Defining Preferences

The application includes options that you can set, and these options remain applied until you change them. The options can help you to operate the application more efficiently.

The File Preferences menu contains several check box options that you can set (enable) or clear (disable). Saved setup files include the File> Preferences settings. View the File Preferences menu.

See also:

File Preferences Options


File Preferences Options


File: Preferences Menu


About Setting up the Application for Analysis

You need to set up the RT-Eye application for serial data analysis or for serial data standard compliance testing. To do so may require that you perform some or all of the following tasks:

•	Choose the probe configuration: differential or single-ended

•	Select all desired measurements

•	Select the Autoset command button

This automatically sets the range of the vertical scale, sets the horizontal resolution, and dynamically sets the waveform crossing thresholds based on signal characteristics.

•	Configure measurement options manually in the Source, Ref Levels, Smart Gating, Jitter, Population, and General Config menus.

•	Select and configure all desired plots (up to four at one time)

After setting up the application, you can select the Start command button to take measurements. The application displays the results as statistics and as plots if you set up the Plots menus and enabled the Plots Display option.

Note: You can enable and adjust Measurement Limits checking to create a Pass or Fail type of compliance test. You can also import industry standard masks and modify or create your own masks files.

After taking measurements, you can do any of the following tasks:

•	View the results as statistics

•	Save statistics in a .csv file

•	View the results as a plot

•	Use the Zoom functions in a plot

•	Use the Cursors functions in a plot

•	Save a plot file

•	Print a plot

•	Save the worst case waveforms as .wfm files

•	Generate a report file


General Steps to Set Up the Application


Selecting an Analysis or Compliance Module

The RT-Eye application supports dedicated, technology-specific compliance modules.

The application accepts Tektronix compliance modules for industry-specified testing. These modules are available as options and require the RT-Eye software. If the application does not detect a compliance module, only "Serial Analysis" appears in the Modules drop-down list. If the application detects other compliance modules, then multiple selections appear in the list.

The RT-Eye online help only discusses the "Serial Analysis" module operation. However, the application also includes separate PDF files with Methods of Implementation (MOI) for the InfiniBand and the PCI Express serial data standards specific to the corresponding compliance module.

The Control Panel shows which module is active. View the Control Panel.


Selecting the Analysis Module

View the default Measurements Select menu.


Selecting a Compliance Module (If Installed and Enabled)
Selecting a Compliance Module

Note: The compliance module must be installed and enabled before you can select it Compliance modules have static configurations and reporting formats unique to a specific standard. In general, you can use these modules for design verification and "Plug-Fest" testing.


Choosing the Probe Configuration

Two of the four typical probing configurations discussed in Connecting to a Device Under Test use two channels to make up the differential serial data signal. Additional measurements are also available with these probing configurations. To set the probing configuration (or if you have two reference waveforms), select Single-Ended as the Probe Type option. If the signal is probed differentially so that the differential signal is delivered to the oscilloscope on a single channel, select Differential as the Probe Type option.

See also:

Probe Information

Probe Type Definitions

Measurement Definitions

About Configuring the Sources


Probe Type Definitions


Selecting a Measurement

You can use the Measurements> Select menu to select measurements for the application to take. The application takes all selected measurements.

This is the default menu when you start the application. You can also access the menu by selecting Measurements> Select in the menu bar.

The measurements will vary depending on the type of probe selected as the Probe Type option. View the Measurements Select menu for differential probes or the menu for single-ended probes.

Use the [image] button to automatically set the Horizontal and Vertical scales of the Sources and the corresponding reference voltage levels. Refer to Autoset Button in Measurements Select menu.

 Use the [image] button as a short cut to the Plots> Select menu.

 Use the [image] button as a short cut to the Measurements> Configure menus.

 Use the [image] button as a short cut to turn on all the available Measurements instead of selecting one measurement at a time.

What do you want to do?

Display the definitions of all measurements

Learn how to configure a measurement

Display the parameters for each measurement

Display the algorithms for each measurement


Measurement Definitions


Measurements: Select Menu for Differential Probes

Note: This is the default menu that appears when you start the RT-Eye application.


Measurements: Select Menu for Single-Ended Probes

Note: The application adds measurements when Single-Ended is selected as the Probe Type option: Differential Skew, CM Voltage, and AC CM Voltage.


Autoset Button in the Measurements Select Menu

Select the [image] button in the Measurements> Select menu to automatically set the vertical scale, horizontal resolution, and reference voltage levels for all active sources. Depending on the settings in the File> Preferences menu, either the autoset operation will occur immediately or the application will display the Autoset Summary menu and wait for you to choose the next action.

The Autoset Summary menu shows the current source autoset and reference level autoset values and parameters in a brief outline view. No autoset operation is performed until you select the [image] command button.

 Use the [image] button as a short cut to the Measurements> Configure menus.

See also:

Autoset Summary Menu Options

Autoset Summary Menu Example

Autoset Summary Menu Parameters

Configure Source Menu Options for a Differential Probe

Configure Source Menu Options for Single-Ended Probes

Configure Ref Levels Menu Options


Autoset Summary Menu Options


Autoset Summary Menu Example


About Configuring a Measurement

Measurements may or may not require configuration. A quick way to configure measurements is to select the Autoset button in the Measurements Select menu.

 Use the [image] button from the Measurements> Select menu as a short cut to the Configure menus.

The application includes the following Configure menus:

•	Source

•	Ref Levels

•	Smart Gating

•	Clock Recovery

•	Jitter

•	Population

•	General Config

See also:

Autoset Summary Menu Options

Configure Menus Definitions


Configure Menus Definitions
Configure Menu Definitions


About Configuring the Sources

The application takes measurements from waveforms or files specified as input sources. You can select an oscilloscope channel input (live), a reference waveform, or a saved waveform file as the source. The selections available for Source Type depend on the Probe Type selected in the Measurements> Select menu.

 Use the [image] button as a short cut to the Measurements Select menu.

View the Configure Source menu for Differential probes

View the Configure Source menu for Single-Ended Probes

See also:

Configure Source Menu Options for a Differential Probe

Configure Source Menu Parameters for a Differential Probe

Configure Source Menu Options for Single-Ended Probes

Configure Source Menu Parameters for a Single-Ended Probe


Configure Source Menu Options for a Differential Probe

Note: Differential probes do not provide common mode voltage components.


Configure: Source Menu for Differential Probes
Configure Source Menu for Differential Probes


Configure: Source from a File for Differential Probes
Configure Source from a File for Differential Probes


Configure Source Menu Options for Single-Ended Probes

Note: You must use single-ended probes for common mode voltage measurements.


Configure: Source Menu for Single-Ended Probes
Configure Source Menu for Single-Ended Probes


Configure: Source from Ref Waveform for Single-Ended Probes
Configure Source from Ref Waveform for Single-Ended Probes


Configure: Source from File for Single-Ended Probes
Configure Source from File for Single-Ended Probes


Autosetting Sources for Live (Channel) Waveforms

In most situations when you want to take measurements from a "live" (channel) waveform, you can usually improve measurement accuracy by using the Autoset options to optimize the vertical scale or horizontal resolution settings of the oscilloscope.

To automatically define the vertical and horizontal settings for a source, follow these steps:

1.	Select Measurements> Configure> Source (or the [image] tab).

2.	For differential probes, select the [image] button.

For single-ended probes, select the [image] button.

3.	In the Select area, choose the specific channel or channels that you are using.

4.	Select one of the Autoset area command buttons. Refer to the Configure Source Menu Options for Single-Ended Probes topic for a description of each option.

Note: The horizontal autoset in RT-Eye places the instrument in the maximum sample rate available. If the 20-80% rise time of the signal is faster than 2X the sample interval, interpolation is recommended to increase accuracy of rise time and jitter measurements.


About Reference Voltage Levels

You need to set reference voltage levels so that the application can identify state transitions on a waveform. Serial data timing measurements are based on state transition times in waveforms. By definition, edges occur when a waveform crosses specified reference voltage levels. There are two ways to set the reference voltage levels: automatically and manually.

See also:

High, Mid and Low Reference Voltage Levels

Rising Versus Falling Thresholds

Using the Hysteresis Option

Steps to Set the Reference Voltage Levels


High, Mid and Low Reference Voltage Levels
High, Mid, and Low Reference Voltage Levels

The application uses three reference voltage levels: High, Mid, and Low.

•	For most Time Interval and Jitter measurements, the application only uses the Mid reference voltage level.

The Mid reference level defines when the waveform transition occurs at a given threshold.For most NRZ AC coupled signals, you would set the Mid reference level to Zero volts.

The Configure Ref Levels menu includes a "Mid = 0V" option which is set by default. You can clear the check box to allow the Autoset function to calculate the proper Mid reference level in the presence of common mode voltages frequently encountered when using single-ended probes.

•	For Rise Time and Fall Time measurements, the High and Low reference voltage levels define when the waveform is fully high or low.

See also:

Rising Versus Falling Thresholds

Using the Hysteresis Option

Configuring the Reference Voltage Levels

Configure Ref Levels Menu Parameters


Reference Voltage Levels Diagram


Rising Versus Falling Thresholds

The option to set separate thresholds for Rising edges vs Falling edges is available in Ref Level Control panel, though the feature is not currently implemented. The High, Mid and Low thresholds entered in the Rise column are actually applied to both rising and falling edges. The values entered in the Fall column are ignored.

See also:

High, Mid and Low Reference Voltage Levels

Using the Hysteresis Option

Configuring the Reference Voltage Levels


Using the Hysteresis Option

The hysteresis option can prevent small amounts of noise in a waveform from producing multiple threshold crossings. You can use a hysteresis when the rising and falling thresholds for a given reference voltage level are set to the same value.

The reference voltage level ± the hysteresis value defines a voltage range that must be fully crossed by the waveform for an edge event to occur. If the decision threshold is crossed more than once before the waveform exits the hysteresis band, the mean value of the first and last crossing times is used as the edge event time.

For example, if the waveform rises through the Threshold - Hysteresis, then rises through the Threshold, then falls through the Threshold, and then rises through both the Threshold and the Threshold + Hysteresis, a single edge event occurs at the mean value of the two rising crossings.

See also:

Example of Hysteresis on a Noisy Waveform


Example of Hysteresis on a Noisy Waveform


Cursor Gating and Reference Voltage Levels Autoset

You can use cursor gating with the reference voltage levels Autoset function. If you enable and set up Cursors in the Configure Smart Gating menu, the application uses the data within the gated region to automatically calculate the reference voltage levels.


Autosetting Reference Voltage Levels
Configuring Reference Voltage Level Autoset

The Autoset Run button on the Ref Levels tab sets all reference voltage thresholds and the hysteresis value to percentages of the base-top voltage amplitude for the waveform. The Ref Level Autoset Setup menu allows you to configure the percentages to define each threshold.

See also:

Configuring Reference Voltage Autoset Percentages

Manually Adjusting the Reference Voltage Levels

How to Enter Alphanumerical Values


Quick Method to Set Reference Voltage Levels
Configuring Reference Voltage Autoset Percentages

The default Reference Level Autoset parameters should be appropriate for most conditions, but you can adjust them for specific situations if you require different behavior.

To configure the Ref Level Autoset Setup menu options, follow these steps:

1.	Select Measurements> Configure> Ref Levels> Autoset Setup.

The Ref Level Autoset Setup menu appears. View the Ref Level Autoset Setup menu.

2.	For each reference voltage level you want to adjust, select the keypad icon or multipurpose knob icon, and enter the percentage of the base to top span of the waveform. The settings are based on the following definitions:

3.	Select the OK button to update the values and close the Ref Level Autoset Setup menu.

4.	Select the Run command button in the Configure Ref Levels menu.

The application calculates the reference voltage levels based on the percentages set in the Ref Level Autoset Setup menu.

5.	If desired, you can manually refine the calculated values in the Configure> Ref Levels menu to suit your analysis situation.

See also:

Steps to Set the Reference Voltage Levels

Ref Level Autoset Setup Menu Options

Configure Ref Level Autoset Setup Menu Parameters


Steps to Set the Reference Voltage Levels

Reference Level Autoset Setup Menu Options


Ref Level Autoset Setup Menu


Manually Adjusting the Reference Voltage Levels

Whether or not you use the application to automatically calculate the reference voltage levels, you may need to manually change the values. To set the reference levels manually, follow these steps:

1.	Select Measurements> Configure> Ref Levels> Source and choose a source (channel or reference waveform) for which you want to set the reference levels. If the Probe Type is differential, only one choice is available.

2.	In the Set Reference Level area, adjust the values of the reference voltage levels and the hysteresis. View the Configure Ref Levels menu.

See also:

Configuring Reference Voltage Autoset Percentages

Autosetting Reference Voltage Levels

Configure Ref Levels Menu Options

Configure Ref Levels Menu Parameters

High, Mid, and Low Reference Voltage Levels

How to Enter Alphanumerical Values


Configure Ref Levels Menu Options


Configure: Ref Levels Menu
Configure Ref Levels Menu

Note: The Source DPlus and DMinus options are only usable when you select Single-Ended as the Probe Type option in the Measurements> Select menu.


About Gated Measurements

Gating allows you to focus the analysis on a specific area of the waveform bound by a gated region, which is a way to filter unnecessary information. To access the Smart Gating menu, select Measurements> Configure> Smart Gating.

You can set up a gated region in one of the following ways:

•	Vertical Cursors

•	Smart Gating

The application uses the Smart Gating function when you select Smart Gating as the Gating option. With Smart Gating, the application establishes a Clock Recovery Window, part of the waveform on which the selected clock recovery method is applied. An Analysis Window is the part of the waveform on which measurements are taken and it is defined relative to the clock recovery window. If you enable scanning, the clock recovery window (with its contained analysis window) is scanned across the acquired waveform according to the scanning parameters. In this case, the results from each scan increment contribute to the population of measurements .The population of measurement appears in the results panel and the associated plots.

See also:

Configure Smart Gating Menu Options

Configure Smart Gating Menu with Gating Off

Configure Smart Gating Menu with Cursors Gating

Configure Smart Gating Menu Parameters

Configure Smart Gating Menu Options for Smart Gating

Configure Smart Gating Menu with Clock Recovery Window

Configure Smart Gating Menu with Analysis Window

Configure Smart Gating Menu with Smart Gating Parameters

Configure Smart Gating Menu with Custom Parameters


Configure Gating Menu Options
Configure Smart Gating Menu Options

See also:

Configure Smart Gating Menu Options for Smart Gating


Configure: Gating Menu with Gating Off
Configure Smart Gating Menu with Gating Off


Configure: Gating Menu with Cursors Gating
Configure Smart Gating Menu with Cursors Gating


Configure Gating Menu Options for Smart Gating (Custom)
Configure Smart Gating Menu Options for Smart Gating


Using Smart Gating

The Smart Gating control consists of a Clock Recovery (CR) window and an Analysis window (Refer to the Smart Gating Diagram). The Clock Recovery and Analysis window can be set to scan the waveform record. You can configure the starting point and length of the CR window. The resulting Stop value (end point) is calculated and displayed. You can also configure the scan increment. The clock recovery method selected on the Clock Recovery tab will be applied to the CR window to establish the reference clock edges for this portion of the waveform.

The Analysis window is defined relative to the CR window using the Length and Alignment controls. If the Alignment control is set to Custom, the Start control defines where the Analysis window begins relative to the CR window. As a convenience, you can select the "Same as Clock Recovery window" check box to make the two windows coincide.

The following example shows how to apply a CR window of 3500 UI and an analysis window of 250 UI, centered within the CR window:

In the CR window:

Start: 1, Length: 3.5k.

In the Analysis window:

Alignment: Centered

Length: 250


Configure: Gating Menu with Clock Recovery Window
Configure Smart Gating Menu with Clock Recovery Window


Configure: Gating Menu with Analysis Window
Configure Smart Gating Menu with Analysis Window


Smart Gating Diagram


Clock Recovery Methods

In serial data standards, jitter measurements are defined in several ways by working standards groups. To make the Time Interval Error (TIE) measurement, you need to first set the jitter reference clock (or ideal clock). All jitter measurements are based on TIE. To comply with industry standards, the RT-Eye application allows you to select various clock recovery methods, which can be generally categorized as either Constant-Clock (mean-squared best fit straight line) or PLL-based.

Whether the clock recovery method is PLL-based or not, you can specify a nominal bit rate to help the clock recovery process. This is especially helpful, for example, when the data pattern on the serial link can be interpreted as a different pattern at a lower rate. A data pattern of 110011001100… at 5.0 Gb/s looks exactly like a pattern of 101010… at 2.5 Gb/s. The application normally uses 2.5 Gb/s rate but you can also select the 5.0 Gb/s by enabling the Nominal data rate control and setting the bit rate.

See also:

About Constant (Straight-Line) Clock Recovery

About PLL-based Clock Recovery

PLL-based Clock Recovery Setup

Clock Recovery Menu Options


About Constant (Straight-Line) Clock Recovery

Constant (straight line) Clock Recovery can be applied to the measurements by selecting a Constant Clock Mean or Median method in the Clock Recovery tab. In Constant Clock Recovery, the clock is assumed to be of the form A*sin (2ðft+ø), where the frequency (f) and phase (ø) are treated as unknown constants. Once a source waveform is acquired and the edges extracted, the clock frequency is selected using linear regression, so that the recovered clock minimizes the mean squared sum of the Time Interval Error (TIE) for that waveform.

If Constant Clock: Mean is selected as the clock recovery method, the phase ø is also chosen to minimize the mean squared error. If Constant Clock: Median is used, the phase is chosen so that the median error between the recovered and measured edges is zero.

See also:

About PLL-based Clock Recovery

Clock Recovery Menu Options

Configure: Clock Recovery Menu


About PLL-based Clock Recovery

When PLL-based clock recovery is selected, the application simulates the behavior of the hardware PLL clock recovery circuit. This is a feedback loop in which the voltage-controlled oscillator (VCO) is used to track or follow slow variations in the bit rate of the input waveform. Such loops are frequently used to recover the clock in communication links that do not transmit the clock as a separate signal. The PLL parameters in the application may be adjusted to synchronize with the behavior of a receiver in such a link, with certain guidelines.

See also:

PLL-based Clock Recovery Setup

About Constant (Straight-Line) Clock Recovery

Clock Recovery Menu Options

Configure: Clock Recovery Menu


PLL-based Clock Recovery Setup

If PLL-based clock recovery is selected, you can choose the loop bandwidth and the loop order. If a second-order loop is chosen, you can specify the damping factor. The loop bandwidth can be selected implicitly by specifying a data communications standard, or it can be set explicitly.

To set the loop bandwidth automatically, based on a serial standard, select PLL: Standard BW as the clock recovery method. From the Standard: b/s list box, select the standard that matches your data link. For example, choose "PCI-E: 2.5" to test a 2.5 Gbit/second PCI-Express link. The PLL bandwidth will be set to 1/1667 of the baud rate.

To manually control the loop bandwidth, select PLL: User BW as the clock recovery method and use the User BW control to select the 3 dB bandwidth of the loop, in Hertz.

You can use the PLL Order list box to choose between first-order and second-order loop. More correctly, this is the loop type, where a type 1 loop has a transfer function that approaches zero frequency with a slope of 1/s and a type 2 loop approaches zero frequency with a 1/s2 slope. The term Order is used in the application in line with popular usage. For a thorough discussion of loop type versus order, see Frequency Synthesis by Phase Lock, by William Egan.

If you choose a second-order loop, the Damping option is enabled. (The Damping Factor does not apply to first-order loops.)

Note: Although it is possible to configure a second-order PLL with a bandwidth as high as 1/10 of the baud rate, such a loop will have poor dynamic performance. This is because second-order loops have less phase margin than first-order loops.


Clock Recovery Menu Options


Configure Clock Recovery Menu


Jitter Measurement Methods

The basic jitter measurement is the Time Interval Error (TIE) measurement. TIE is a measure, on a cycle-by-cycle basis, of how far each edge differs in time from where the edge ideally should have occurred. In this context, "Ideal" is determined by the clock recovery method. Apart from choosing and configuring the clock recovery method and reference levels, no specific setup is required for a TIE jitter measurement.

The advanced form of jitter analysis is jitter separation, also known as Rj/Dj analysis. This analysis breaks the timing jitter into various categories and uses the results to predict the total jitter at a selected bit error rate (BER). The RT-Eye application offers two methods of Rj/Dj analysis:

•	A method based on spectral analysis that is appropriate for cyclic repeating data patterns

•	A method that works for any arbitrary data pattern

See also:

Rj/Dj Analysis of Repeating Patterns Using a Spectral Approach

Configure Jitter Menu for Repeating Patterns

Rj/Dj Analysis of Arbitrary Patterns

Configure Jitter Menu for Arbitrary Patterns

Bathtub Curve: BER versus Decision Curve


Rj/Dj Analysis of Repeating Patterns Using a Spectral Approach

This method of Rj/Dj analysis uses a Fourier transform of the time-interval error signal to identify and separate jitter components. It is described in the Fibre Channel - Methodologies for Jitter and Signal Quality Specification (MJSQ) and was the analysis method originally introduced with the RT-Eye application.

This method requires that the data signal be composed of a pattern of N bits that are repeated over and over. The pattern length (N) must be known, although it is not necessary to know the specific bits that make up the pattern.

See also:

Configure Jitter Menu Options

Configure Jitter Menu for Repeating Patterns

Rj/Dj Analysis of Arbitrary Patterns

Bathtub Curve:BER Versus Decision Time


RjDj Analysis of Arbitrary Pattern

When the data pattern is not repeating, or is unknown, a second method of Rj/Dj analysis may be used. (It may also be used if the pattern is repeating, and correlates well with the Spectral method in this case.) This method assumes that the effects of Inter Symbol Interference (ISI) only last for a few bits. For example, in a band-limited link where a string of ones follows a string of zeros, the signal may require three or four bit periods to fully settle to the "high" state.

In this method, an analysis window with a width of K bits is slid along the waveform. For each position of the window, the time interval error of the rightmost bit in the window is stored, along with the K-1 bit pattern that preceded it. After the window has been slid across all positions, it is possible to calculate the component of the jitter that is correlated with each observed K-1 bit pattern, by averaging together all the observed errors associated with that specific pattern.

In the configuration menu for the arbitrary-pattern method, the Window Length field allows you to select how many bits are included in the sliding window. The window should include enough bits to encompass the impulse response of the system under test, usually 5 to 10 bits. A good practical test is to check whether increasing the window length causes any appreciable change in the jitter results; if not, the window length is effectively capturing all the ISI effects. The disadvantage of increasing the window length is that it uses more memory and slows the processing.

The configuration menu also includes a field for selecting what population of each K-1 bit pattern must be accumulated before the TIE associated with that pattern is considered accurate. Using a larger population means that more observations are averaged together, so that the variance of the measurement is reduced. Specifying a larger population has the disadvantage of requiring a longer measurement period before results can be calculated.

It may be necessary to sequence the instrument several times before enough statistics are accumulated to provide results.

The arbitrary pattern approach for measuring jitter may not be appropriate if there are very-long-duration memory effects in your data link. An example would be if there are impedance mismatch reflections that arrive long enough after the initial edge to fall outside the analysis window.

See also:

Configure Jitter Menu Options

Configure Jitter Menu for Arbitrary Patterns

Rj/Dj Analysis of Repeating Patterns Using a Spectral Approach

Bathtub Curve: BER versus Decision Time


Configure Jitter Menu Options


Configure Jitter menu for Repeating patterns


Configure Jitter menu for Arbitrary patterns


Bathtub Curve: BER versus Decision Time

The Bathtub Curve plot shows the eye opening and total jitter values as functions of the BER level. The plot is obtained from the Rj/Dj separation that is automatically performed when a Jitter@BER measurement is executed.


Setting the Population for the Measurements

The Population control allows you to limit the amount of waveform data that is analyzed. This is often done in industry standards to make sure that there is consistency between measurement techniques. You can use the Configure Population menu to set a limit on a maximum population to obtain for all selected measurements. View the Configure Population menu.

To define the maximum population for measurements, follow these steps:

1.	Select Measurements> Configure> Population> On.

2.	Select Limit By and choose a waveform characteristic on which to base the population.

3.	Select Limit and specify a population limit from one to one million.

If you use a population limit, Statistics individually accumulate for each measurement that reports the Current acquisition statistic to the population limit. A Free Run stops when all such active measurements reach the population limit. An acquisition population limit applies to all active measurements; statistics will accumulate until the acquisition limit is reached.

You can use a population limit for a Single Run. If the limit is less than the normal population for that Single Run then the measurement statistics will stop at the limit.

See also:

Configure Population Menu Options

Configure Population Menu Parameters


Configure Population Menu Options


Configure Population Menu


About Using Measurements Limits File

Each serial data application provides a Limits file that includes combinations of all measurements and statistical characteristics, and an appropriate range of values for each combination. The application can use the Limits file and a mask file to determine the Pass or Fail status for compliance tests.

To test against a Limits file, you need to enable measurements limits checking, and enable a mask file in the Plots menus. View the Measurements Limits menu.

See also:

Creating a Measurements Limits file

Editing a Measurements Limits file

Measurements Limits Menu Options

Measurements Limits Menu Parameters

Measurements Limits Editor Toolbar Functions

Measurements Limits Editor Menu Options


Creating a Measurements Limits File

You can use the Limits File Editor functions to create a Limits file. The editor includes variable range options to suit your specific needs.

To create a Limits file, follow these steps:

1.	Select Measurements> Limits.

2.	Select [image]. The Limits Editor window appears.

3.	Select [image]. The editor adds a measurement with None selected.

4.	In the new row, select a Measurement, type of Statistic, a Lower Limit value and an Upper Limit value as appropriate. View an example of a Measurements Limits Editor window.

5.	Select [image]. The application verifies that the limits for each measurement are valid and that there are no duplicates.

6.	Select [image]. The application removes measurements where the selection is None.

7.	Select File> Show Summary. View an example of a Show Summary list from the limits file.

The next time you select [image], the application compares the measurement results against the Limits file and the mask file, and then displays the status as Pass or Fail in the results menus.


Editing a Measurements Limits File

You can use the Limits File Editor functions to edit an existing Limits file. To edit a Limits file, follow these steps:

1.	Select Measurements> Limits.

2.	Select [image] and navigate to the directory where the Limits file resides.

3.	Select a file, and then Open.

The selected file appears in the Limits Editor window.

4.	Edit the file as necessary. To delete a measurement, select None.

5.	Select [image]. The application verifies that the limits for each measurement are valid and that there are no duplicates.

6.	Select [image] to remove the rows where None is selected as the measurement.

7.	Select File> Show Summary. View an example of a Show Summary list from the limits file.


Measurements Limits Menu Options


Measurements: Limits Menu
Measurements Limits Menu


Measurements Limits Editor Toolbar Functions


Measurements Limits Editor Menu Options


Measurements: Limits Editor Menu
Measurements Limits Editor Menu


Measurements Limits File Summary


About Serial Data Wizard
About the Serial Data Wizard

The RT-Eye application Setup Wizard guides you through the process of setting up, running, and displaying the results of a measurement using an intuitive sequential process. The Wizard can be used for accurate measurements for a single acquisition, or as a starting point for advanced configurations, or free-run measurements.

Note: The statistical results for the Setup Wizard and RT-Eye application are identical if the measurements and setups are the same.

Select Measurements> Wizard to open the Setup Wizard anytime. You can also open the Setup Wizard during the launch of the RT-Eye application by clicking Run Wizard in the

RT-Eye Welcome dialog. Refer to Starting the Application for more information.

The Setup Wizard takes you through the steps to configure the following parameters:

•	Probe type

•	Measurement Sources

•	Standards

•	Measurement Categories

•	Autoset Source Levels

•	Autoset Source Reference Levels

•	Plots

Note: You can exit the Setup Wizard without affecting any settings in the Serial Analysis application by clicking Cancel anytime before clicking the Run button.


Probe type

In this step, you can select the type of probe. The default probe type is Single-ended. In the single-ended probe configuration, you connect two probes or two SMA cables to the unit under test and the application forms a pseudo-differential signal by subtracting them. See Probe Diagrams A and C ". In the differential probe configuration, you connect a single differential probe, as shown in Probe Diagrams B and D.

Note that the currently selected step is always highlighted in the left column of the Wizard.

Click Next to accept your probe type and proceed to Measurement Sources.


Measurements Sources
Measurement Sources

In step 2, you can select the Measurement sources. The available sources depend on which probe type you have selected in the previous step. The selection in the previous step is displayed in yellow text as shown in the following figure.

Click Next to proceed to Standards. Click Back if you want to change the probe type.


Standards Selection

In step 3, you select the Serial Analysis standards that guide clock recovery by establishing the bit rate. The default standard is PCI-E : 2.5 G.

Click Next to proceed to Measurement Categories.


Measurement Category
Measurement Categories

In step 4, you select the Measurement that will be performed. Various measurement parameters are grouped under these categories. You need to select at least one measurement to advance to the next step. For more details, refer to Selecting a Measurement.

If you select Jitter@BER measurement, you can set the pattern length by selecting Repeating pattern and then entering the pattern length in the Pat Len text box. The default value is 2500 unit intervals. If you have a non-repeating waveform pattern or if the pattern length is unknown, select Arbitrary.

Note: The measurements that you select also determine which plot types will be available in step 7.

Click Next to proceed to step 5, where you select whether to Autoset the source scales.


Autoset Source Levels

In step 5, you can choose to automatically adjust the horizontal and vertical scaling before the measurement. This is similar to the Autoset feature of the oscilloscope. The default of Yes is recommended unless you select a reference source. If you select No, you will retain the current oscilloscope settings.

Click Next to proceed to Autoset the source reference levels.


Autoset Source Reference Levels

In step 6, you can choose to automatically adjust the reference levels before the measurement. The reference levels are the voltage thresholds that are compared to the waveform to determine when timing events occur. The default of Yes is recommended.

Click Next to proceed to Plot selection.


Plots

In step 7, you can select the plot types that you want to display. Some plot types may not be available depending on the measurements that you chose in the Measurement Categories step. The default is to select all plot types. The types of plots available are:

•	Eye Diagram—Default and is available for all measurements

•	Spectrum—if TIE Jitter is selected

•	Bathtub Curve—if Jitter@BER is selected

•	Jitter Histogram—if TIE Jitter is selected

Click Run to start a single acquisition sequence using the selected settings. The Plot waveform diagrams are displayed in the chosen order, as shown in the following figure.


Saving My Test

To save the current application and oscilloscope settings without closing the RT-Eye application, select Measurements> Save MyTest.

You can also save your MyTest before exiting the RT-Eye application. When you select

File> Exit from the RT-Eye application, the application prompts you to save the oscilloscope settings. If you select the Save MyTest check box, the current setup will be saved as the new MyTest.


Running My Test

Select Measurements> Run MyTest to run MyTest at any time.

The application takes the measurements from the saved MyTest and displays the results in the Result summary window. You can also run MyTest directly from the RT-Eye Welcome dialog. Refer to Starting the Application.


About Using User Masks
About Using Standard Masks

You can use masks based on serial data standards for compliance testing of DUTs.

Industry standard masks are available from the file browser in the Plots Configure menu (for an Eye Diagram plot). The mask files are selected from the following directory:

  C:/TekApplications/tdsrt-eye/Examples/Masks

The standards supported are as follows:

•	InfiniBand

•	PCI Express

•	Ethernet (Including XAUI)

•	1394B

•	Fibre Channel

•	FB-DIMM

•	Serial ATA

•	SAS (Serial Attached SCSI)

•	Serial Rapid IO

You can edit a mask file to create a custom user mask through one of the following methods:

•	Using the User Mask File Editor available in the Mask menu (if enabled) in your oscilloscope

•	Manually using a text editor

See also:

Creating a New User Mask File

Plots Configure Menu Options for an Eye Diagram


Using the User Mask File Editor

To edit a mask file with the User Mask File Editor of the oscilloscope, follow these steps:

1.	From the menu bar of the oscilloscope, select Masks> Mask Edit Setup.

2.	Select the Recall button and navigate to the following directory:

C:\TekApplications\tdsrt-eye\modules\SerialAnalysis\masks

3.	Recall the user.msk file.

4.	Follow the instructions in the online help of the oscilloscope to edit and save the file.

See also:

Mask File in the Oscilloscope Mask Editor

Import of User Masks

Manually Editing a Mask File


Mask File in the Oscilloscope Mask Editor


Plots Configure Menu Setup for User Masks
Import of User Mask


Manually Editing a Mask File

If you do not have a Mask Editor available in your oscilloscope, you can use a text editor to manually edit a mask file.

The User Mask File Opened in a Text Editor diagram shows an .msk file revised using the Mask Editor in a TDS7000 series oscilloscope. The diagram shows the fields used by the

RT-Eye application in red boxes.

Note: The application ignores all other fields. The mask file must contain SEG1, SEG2, and SEG3 fields for proper operation.

To change the geometry of the mask, use a text editor to edit the following fields:

See also:

Recalling a User Mask in the Plots Configure Menu

Creating a New User Mask File

Mask File Edited Using a Text Editor Example


User Mask File Opened in a Text Editor

This diagram shows the fields used by the RT-Eye application in red boxes. You can edit these fields to change the geometry of the mask.


Creating a New User Mask File

If need be, you can create a new User Mask file using a text editor. This is an alternative to editing an existing mask. To do so, follow these steps:

1.	Create a new file using a text editor.

2.	Enter User Mask information.

3.	Save as a .msk file.

4.	Recall the file in the Plots Configure menu.

See also:

Mask File Edited Using a Text Editor Example

Recalling a User Mask in the Plots Configure Menu

Manually Editing a Mask File


Mask File Edited Using a Text Editor Example


Recalling a User Mask in the Plots Configure Menu

To recall a User Mask file to the RT-Eye application, follow these steps:

1.	From the menu bar of the RT-Eye application, select Plots> Configure.

2.	Select On in the Mask area.

3.	Select User as the Standard option.

See also:

Plots Configure Menu Options for an Eye Diagram


About Taking Measurements

If you want to change trigger settings or localize the measurement, you should do so before you take any measurements.

Note: If you select a reference waveform as the source, you need to recall and display the waveform on the oscilloscope before the application can take a measurement. To do so, refer to recalling a waveform file.

Note: If an error message appears because there are not enough cycles from which to take a measurement, adjust the Horizontal setting on the oscilloscope to increase cycles.

See also:

Gating Measurements


Localizing Measurements

By specifying the trigger position, the starting point, and the length of the waveform, you can effectively filter out information that is not useful to analyze before taking a measurement.

To focus the application measurement on a part of the waveform, you can use the

Configure Smart Gating menu. You can also adjust the Record Length, Scale, or pre-trigger information in the oscilloscope Horizontal menu, or the trigger level and slope in the Trigger menu.

You can also set up the File Preferences menu for the application to use only transition bits.

See also:

Defining Preferences

Gated Measurements


About Sequencing

You use the Control Panel to start or stop the sequence of processes for the application and oscilloscope to acquire information from a waveform. The application then determines if the algorithm for the selected measurement can be applied to the waveform information. Sequencing is the steps to acquire waveform information, determine if the information is usable for the measurement, take the measurement, and display the results.

There are three Sequencing modes: Single Run, Single No Acq, and Free Run. View the Control Panel.

See also:

Acquiring Data

Sequence Mode Option Definitions


Acquiring Data

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

1.	In the Control Panel (on the right side of the application display), select a Sequence mode.

2.	The application uses the Sequence mode to acquire waveforms and take measurements when you select the Start command button. The choices are: Single Run, Free Run, and Single No Acq.

3.	Select the [image] button for continuous acquisitions or for measurements on a new or existing acquisition.

4.	If you select the Single Run or the Single No Acq mode, the application displays the results when the sequencing is complete.

5.	If you select the Free Run mode or decide to stop sequencing, select the [image] Stop button to stop the sequencing. In Free Run mode, the sequencing also stops once the application has reached the limit set in the Configure Population menu.

Note: The application displays a status bar when it is busy sequencing. The status at the bottom of the Control Panel indicates Ready when the sequencing is complete. It may also indicate Stopping before indicating Ready.

 Use the [image] command button to delete all measurement results.

See also:

Sequencing

Control Panel Functions

Control Panel Parameters


Control Panel Functions


Sequence Mode Option Definitions

Chunking/Scan mode behavior of Eye Plot

In this mode, the waveform is analyzed from the Start value to the Stop value configured in Smart Gating tab. The number of scans depends upon the scan increment and size of the window values. For example, if an eye diagram is selected, then the eye diagram plot keeps updating with new result for each window.

The RT-Eye application can be configured in different modes and the results vary accordingly. The modes are:

•	Single shot, scan mode off

•	Single shot, scan mode on

•	Free run, scan mode on

•	Free run, scan mode off

Single shot, Scan mode off

The application acquires and analyzes the entire waveform and then holds with the analyzed waveform on the oscilloscope display. The entire waveform (or the gated portion of the waveform, if cursor or smart gating is employed) is analyzed and the result is displayed in a single shot. For example, if an eye diagram is selected, then each data bit in the gated portion of the waveform appears in the center of the eye diagram exactly one time.

Single shot, Scan mode on

The application acquires and retains the entire waveform, and then analyzes the configured scan windows. After each scan window is analyzed, the results for that window are added to the cumulative results and the eye diagram, if displayed, accumulates the eye results from the latest window with all prior windows. Depending on the gating and scanning parameters, some bits in the waveform may not be analyzed or some may be analyzed two or more times.  An option is available to select worst case results, in which case, the worst of all the scan windows analyzed is shown. An option is available to select worst case results in which case the worst of all the scan windows analyzed is shown.

Free run, Scan mode off

The application acquires the waveform, analyzes it, accumulates the results with any existing results, and refreshes all plots. The cycle repeats immediately. This continues until the Stop button is clicked or the population limit is reached.

Free run, Scan mode on

The application acquires the waveform and performs one analysis cycle on each scan window, thus updating the results and plots after each scan window. Once the configured number of scan windows has been analyzed, a new waveform is acquired and the measurement cycle is repeated. This continues until the Stop button is clicked or the population limit is reached.


Control Panel


About the Results

There are two ways to view the results after an analysis is complete: statistical values or graphical plots.

If you enable the plots before taking measurements, the application shows the selected plots in a separate window in the oscilloscope part of the display. The application shows statistics in the application part of the display. When you use a Limits Module, the application also shows the results as Pass or Fail.

See also:

Results: Summary Menu

Results: Details Menu

Saving Statistics Results

Selecting Plots

Configuring Plots

Plot Summary Window Example

Plot Details Window Example

Using a Separate Monitor to View Plots

Saving and Printing Plots


About Viewing Statistics

There are two ways to view the statistical results of measurements: Results Summary Menu and Results Details Menu.

See also:

Viewing Plots


Viewing Statistics

To view measurement statistics, select the Results Summary or the Results Details menu. The application displays results for the measurements of all acquisitions or for the current acquisition.

The Results Summary menu shows the current data and all acquisition data for each statistical value.

The Results Details menu contains statistical values for the following characteristics:

•	Population

•	Mean

•	Standard deviation (StdDev)

•	Maximum (Max)

•	Minimum (Min)

•	Pk-Pk

See the Results Summary menu for an example of the tabular listing of statistics of selected measurements.

See the Results Details menu for an example of details of selected measurements.

See also:

Results Summary Menu Options

Results Summary Menu Parameters

Results Details Menu Options

Results Details Menu Parameters

Saving Statistics to a .CSV File

Algorithms Used to Calculate Statistics

Viewing Plots


Results Summary Menu Options


Results: Summary Menu
Results Summary Menu


Results Details Menu Options


Results: Details Menu
Results Details Menu


Saving Statistics to a .CSV File

You can save the statistics to a "comma separated variable" file to import into a text editor, a spreadsheet, or an analysis tool. View the Results Summary menu or the Results Details menu.

To save the results summary or details to a "comma separated variable" (.csv) file, follow these steps:

1.	Select either Results menu.

2.	For the Results Details menu, select the measurement whose details you want to save from the Results Details Select View drop-down list.

For the Results Summary menu, Limits Status is only available if you enabled measurement limits before taking measurements.

3.	Set the Time Units option to Seconds or to Unit Interval. To save both types of information, you need to save two .csv files.

4.	Select the [image] button. The Save browser opens.

5.	Enter a file name. The application appends the .csv suffix to the name.

6.	Select the Save button to save the file.

•	If the oscilloscope is connected to a network, you can use the Explorer to move the file.

•	If the oscilloscope is not connected to a network, you can copy the file to a floppy disk.

View an example of a .csv file using a text editor.

View an example of a .csv file edited in a spreadsheet program.


About Plotting

The application can display the results as two-dimensional plots for easier analysis. Before you take measurements, you can set up the Plots Select and Plots Configure menus to define up to four plots. When enabled, the plots will display when the application completes sequencing.

The application uses MATLAB-based windows to display plots.

Would you like to learn more about the plots, such as how the application computes each or when each is a good choice to use for analysis?

Eye Diagram Plot Usage

Bit Error Locator Usage

Histogram Plot Usage

Spectrum Plot Usage

Bathtub Plot Usage

Note: When taking measurements in the Free Run mode, you must stop the sequencing before you use the Plots Select or Plots Configure menus.

Note: Be sure to configure a printer before you print a plot.

See also:

Plot Type Definitions

Measurements and Available Plots

Plot Window Layouts

Selecting Plots

Configuring Plots

Viewing Plots


Plot Type Definitions


Measurements and Available Plots

Note: Measurements not listed are unsuitable for plots (Unit Interval, Differential Skew, Differential Voltage, High Amplitude, Low Amplitude, CM Voltage, and AC CM Voltage).


Plot Window Layouts


Using a Separate Monitor to View Plots

If your oscilloscope setup includes a second monitor that extends the Windows desktop, you can select and drag the title bar of the plot window to position it in the second monitor. This allows you to simultaneously display a waveform on the oscilloscope, the RT-Eye measurement results, and the plot for easy viewing.


Eye Diagram Plot Usage

The clock recovery used for Real-Time Eye (RT-Eye) rendering is software based. The ideal clock (jitter reference clock) is recovered from the serial bit stream. The actual locations of the rising and falling edges of the acquired waveform are then "rendered" with respect to the recovered clock, creating an eye diagram. The clock is recovered from a single waveform acquisition which means that trigger jitter is eliminated from the eye diagram.

If you use a CSA7000 series or a TDS6000/7000 series oscilloscope with Option SM, hardware (HW) clock recovery is also available through the Masks menu in the oscilloscope application. The HW clock recovery is based on phase-locked loop (PLL).

Eye diagrams created using HW PLL are called Equivalent Time (ET) eye diagrams and are susceptible to trigger jitter. The ET Eye diagram is useful as a first check of signal quality and for debug purposes. RT-Eye rendering provides high precision "de-jittered" eye diagram with a very small Jitter Noise Floor (JNF) required for compliance testing.

See also:

RT-Eye Rendering

ET-Eye Rendering

Selecting Plots

Configuring Plots

Viewing Plots

About Using User Masks

Plots Configure Menu Options for an Eye Diagram

Plots Configure Menu for an Eye Diagram

Eye Diagram Configure Menu Parameters


RT-Eye (Real Time) Rendering


ET-Eye (Equivalent Time) Rendering


Usage of Waveform with Bit Error Locator

You can find eye diagram mask failures on waveforms using the Bit Error Locator feature. The white on the mask shows waveform mask violations. The same violations can also be seen on pulse plot. The pulse plot shows the acquired waveform data similar to the oscilloscope screen. You can correlate the failures between the Eye Diagram and the waveform by looking at the red violations. From the waveform plot, and whether it failed on the rising or falling edge of the sample. This technique is useful for discovering data dependent behavior that may be causing bit errors. The waveform plot can be used in conjunction with the oscilloscopes waveform displays to time correlate failures due to crosstalk or power supply noise. For instance, Ch2 can be used to acquire the suspected offender signal and it can be compared to the serial data signal acquired on Ch1 for time correlation.


Histogram Plot Usage

Histogram plots display the results such that the horizontal axis represents the measurement values and the vertical axis represents the number of times that the value occurred. Unlike any other plot, a histogram plot accumulates measurements over multiple acquisitions, up to a total population size of 2.1 billion.

Histograms are particularly useful in analyzing jitter. A histogram of the Time Interval Error (TIE) represents the basis of jitter analysis using a histogram approach. In a histogram, Deterministic Jitter (Dj) is bounded in a system and shows up as a non-gaussian distribution. Random Jitter (Rj) is unbounded and amplitude will continue to grow the more population is acquired. The TIE histogram is a good first look analysis of jitter.

See also:

Selecting Plots

Configuring Plots

Viewing Plots

Plots Configure Menu Options for a Histogram

Histogram Plot Configure Menu Parameters


Spectrum Plot Usage

A spectrum plot is the Fourier transform of measurement values versus time. This plot is useful in identifying frequency components that contribute to timing errors, such as modulation of the measurements. An example of where this is useful is plotting a "Jitter Spectrum". Jitter Spectrum is the FFT of the trend of time interval error. This reveals the frequency components of the output jitter.

Further analysis on the Jitter Spectrum can be used to separate Random Jitter (Rj) from Deterministic Jitter (Dj) as well as separate Dj components of Periodic Jitter (Pj) and other Dj components such as ISI and DCD. The frequency of periodic jitter spikes that do not correlate to frequencies contained in the data pattern can be a clue that you should look at frequencies of different components in your design as possible sources of jitter.

See also:

Selecting Plots

Configuring Plots

Viewing Plots

Plots Configure Menu for a Spectrum

Spectrum Plot Configure Menu Parameters


Bathtub Plot Usage

Bathtub curves are the industry standard way of viewing the Jitter Eye Opening. A Bathtub curve represents a plot of the eye opening versus the BER (Bit Error Ratio). Most 8B/10B encoded copper standards call for Total Jitter to be measured at 10-12 BER. The eye opening represented by the Bathtub Curve is what is left of the unit interval after the total jitter measurement is subtracted. A detailed discussion of bathtub analysis can be found in the MJSQ document at www.t11.org.

The Jitter Eye opening and the Total Jitter have the following relationship:

Total Jitter + Jitter Eye Opening = 1 Unit Interval

See also:

Selecting Plots

Configuring Plots

Viewing Plots

Plots Configure Menu Option for a Bathtub

Bathtub Plot Configure Menu Parameter


Selecting Plots for Configuration

Before you take measurements, you can set up plots in the Plots Select menu.

To select a plot to configure, follow these steps:

1.	Select Plots>Select. View the Plots Select menu.

2.	Select the On button.

3.	Select a measurement in the Select Measurement column.

4.	Select a plot type in the Select Subplot column.

 Use the [image] button as a short cut to the Measurements> Select menu.

See also:

Configuring Plots

Viewing Plots

Removing Plots

Plots Select Menu Options

Plots Select Menu Parameters


Plots Select Menu Options


Plots: Select Menu


Configuring Plots

After you select the plots, you can further configure each measurement and plot combination. The options are relative to the selected plot type in the Subplot column.

To configure a plot, follow these steps:

1.	Select the [image] tab.

2.	Select a measurement in the Select Measurement column.

3.	Select a plot type in the Select Subplot column. Plot options depend on the type of selected plot.

For the Eye Diagram plot, masks are available for many standards and you can create your own custom designed mask. For more information on User masks, refer to the About Using User Masks topic.

4.	Configure the plot.

5.	Select the [image] tab.

6.	Select the [image] command button.

The Plot Summary Window updates and displays the selected plots. View an example of the Plot Summary Window.

See also:

Plots Configure Menu Options for an Eye Diagram

Plots Configure Menu for an Eye Diagram

Plots Configure Menu Options for a Histogram

Plots Configure Menu for a Histogram

Plots Configure Menu Options for a Spectrum

Plots Configure Menu for a Spectrum

Plots Configure Menu Option for a Bathtub

Plots Configure Menu for a Bathtub

Selecting Plots

Viewing Plots


Plots Configure Menu Options for an Eye Diagram

Note: For more information, refer to Eye Diagram Plot Usage.


Plots Configure Menu for an Eye Diagram

Note: For more information, refer to Eye Diagram Plot Usage.


Plots Configure Menu Options for a Histogram

Note: For more information, refer to Histogram Plot Usage.


Plots Configure Menu for a Histogram

Note: For more information, refer to Histogram Plot Usage.


Plots Configure Menu Options for a Spectrum

Note: For more information, refer to Spectrum Plot Usage.


Plots Configure Menu for a Spectrum

Note: For more information, refer to Spectrum Plot Usage.


Plots Configure Menu Option for a Bathtub

Note: For more information, refer to Bathtub Plot Usage.


Plots Configure Menu for a Bathtub

Note: For more information, refer to Bathtub Plot Usage.


About Viewing Plots

There are two windows you can use to view and analyze plots: Plot Summary and Plot Details. The application includes tools to help you size and position the window, display either window, and display the details of another plot directly from the details window.

After you select and configure a plot, select the [image] command button. When sequencing is complete, the Plot Summary Window appears with up to four plots. View an example of a Plot Summary Window.

If you reconfigure a plot and want to view the updated plot, follow these steps:

1.	Select the [image] button.

2.	Select the [image] command button.

The plots window updates according to any changes you made to the Plots Select or Plots Configure menus.

The Plot Details tools represent the plots by quadrant in the Plot Summary Window. View Show Plot Details tools. For example, you can select the [image] tool to display details for the plot in the upper left quarter of the Plot Summary window. View an example of a Plot Details Window.

 If you have a keyboard, you can use the alt-tab Window shortcut to quickly select a window for viewing.

 If you have a second monitor, you can select and drag the title bar of the plot window to position it in the other monitor.

See also:

Toolbar Functions in Plot Windows

Plot Summary and Details Window Example

About Using Zoom in a Plot

About Using Cursors in a Plot

About Saving Plot Files


Toolbar Functions in Plot Windows

The Plot Summary window includes the following toolbar:

The Plot Details window includes the following toolbar:

Some functions are specific to the Plot Summary window and others are specific to the Plot Details window. The next table lists the available functions in each type of plot window.


Plot Summary Window Example

This plot window includes save, print, view details, and size and position window functions.


Plot Details Window Example

This plot window includes save, print, zoom, cursors, grid, view summary, and size and position window functions.


Plot Summary and Details Window Example


Viewing a Plot in the Whole Display or in Half the Display

You can change the plot size to the whole display of the oscilloscope, or to half the display. When viewing a plot in half the display, you can position the plot in the upper or lower half.

•	 enlarges the plot to fill the entire display

•	 reduces the plot to half the display, if need be, and positions it in the upper half

•	 reduces the plot to half the display, if need be, and positions it in the lower half


Returning to the Plot Summary Window

To return to the Plot Summary window, select the [image] tool.


Using Zoom and Cursors in a Plot

You can use the zoom and the cursors functions simultaneously in the Plot Details window. To do so, follow these steps:

1.	Select the [image] tool and draw a box around the area bound with the cursors.

2.	Use the cursors to take measurements.

3.	Repeat the previous steps if need be. You can zoom in by a magnification of 20X.

4.	Select the [image] and the [image] tools to display the horizontal and the vertical cursors.

5.	Move the cursors to bound the area you want to view more closely.

See also:

About Using Zoom in a Plot

About Using Cursors in a Plot


Removing Plots

To remove a plot from a plot window, follow these steps:

1.	Select Plots> Select.

2.	Select None for the measurement in the Select Measurement column.

3.	Select the [image] command button.

The plot window updates and does not display the deselected plot.


About Using Zoom in a Plot

Once you have created a plot, you can use the Zoom tools in either plot window to examine the data at various scales. View the Plot Zoom tools.

 You can quickly restore the view to display all the data. To do so, select the [image] tool.

 If you prefer to move the cursors in the plot window with your finger, you can activate the Touch Screen on the oscilloscope.

See also:

Plot Zoom Definitions

Changing the Scale of Data in a Plot (Zoom)


Plot Zoom Definitions


Changing the Scale of Data in a Plot (Zoom)

To change the scale of the data in a Plot Details window, select one of the following plot zoom tools:

•	 zooms in to expand the scale

•	 zooms out to contract the scale

•	 zooms in to expand the horizontal axis only

•	 zooms in to restore all the data

When you select the [image] tool, you can use a select-drag-release action to expand part of the waveform (zoom in) by an arbitrary amount on both axes. After you select (touch with a finger or click with the mouse) and begin dragging, a bounding box shows what part of the waveform will be expanded upon release.

Select any part of the plot to expand the data by a factor of two (2X) equally on both axes. Double selecting expands the data to the maximum factor.

To contract an expanded part of the data (zoom out), select anywhere on the data. The view contracts to the values that existed before the most recent expansion of the data. Selecting multiple times will restore successively earlier views.

To expand the scale of the horizontal axis only by a factor of two (2X), click a part of the waveform. The plot retains the scale of the vertical axis.

 You can quickly restore the view to the entire waveform. To do so, select the [image] tool.


About Using Cursors in a Plot

Cursors allow you to view numerical values associated with a plot based on cursor locations. There are two cursor modes: Horizontal-paired and Vertical-paired. Each mode displays two cursors. View the Plot Cursor tools.

See also:

Plot Cursors Definitions

Using Cursors in a Plot

About Using Zoom in a Plot

Using Zoom and Cursors in a Plot


Plot Cursors Definitions


Using Cursors in a Plot

You can use cursors to read the coordinate where each cursor (line) touches the plot and also view the difference (delta) between the two cursors.

To use cursors in the Plot Details window, follow these steps:

1.	Select one of the following cursor tools:

•	 to use Horizontal cursors

•	 to use Vertical cursors

•	 to bring the cursors into the visible plot

2.	Select and drag either cursor to move the cursor to the desired part of the plot.

The cursor readout changes value to reflect the cursor position.

Note: You can drag cursors only when the Zoom functions are disabled.

 If you prefer to move the cursors in the plot window with your finger, you can activate the Touch Screen on the oscilloscope.

See also:

Horizontal and Vertical Cursors in a Plot Example

Using Zoom and Cursors in a Plot


Using Grid Points in a Plot

To display or remove cursor points in a Plot Details window, select the [image] tool. Grids are not available in eye diagrams.


Horizontal and Vertical Cursors in a Plot Example


About Saving Plot Files

Both plot windows include the save plot file tools. However, the contents of saved plot files are dependent on the type of plot window: Summary or Detail. View the Save Plot to a file command buttons.

See also:

Save Plot Files Definitions

Saving Plot Files


Save Plot Files Definitions


Saving Plot Files

To save a plot file, follow these steps:

1.	Set up the plot window.

2.	Select one of the following save plot file tools:

•	 to save the plot as graphic file

•	 to save a data file

3.	Select the [image] button to select a directory and then enter a file name.

4.	Select the [image] button to save the plot file. The application saves the file.

See also:

File Name Extensions


About Printing Plots

To send a plot to a printer, follow these steps:

1.	Verify that a printer is configured.

2.	Set up the plot window (with the zoom, cursor, or grid points functions).

3.	Select the [image] tool.

4.	The Plot Print dialog appears. View the Plot Print Preview window.

5.	Select the [image] button and set up the options.

6.	To customize the print of the plot, select the [image] tool.

7.	The Page Setup menu that is a part of the MATLAB software appears. View the Page Setup window

Note: The online help topics for the RT-Eye application do NOT describe how to use the MATLAB Page Setup menu. Refer to the MATLAB documentation for more information.

Select the Print button to print the plot file. If you selected Print to File, use the [image] button to select a directory and then enter a file name. The application saves the file.


Plot Print Preview Window


Plot Page Setup Window


Saving Worst Case Waveforms from a Live Source

You can use the Log Worst Case menus to save the acquired waveforms whenever a selected measurement exceeds the highest or lowest prior value. When enabled, the waveforms are saved to a set of .wfm files. View the Log Worst Case Waveform menu.

The application also exports the contents of the files to a worstcasetable.csv file located in the Log directory.

To log worst case waveforms, follow these steps:

1.	Select Log> Worst Case> Configure.

2.	Select the [image] button to enable logging.

3.	Select the [image] button to select a directory.

4.	Select the [image] command button in the Control Panel.

The application saves the waveforms with the worst case maximum and minimum values for all selected measurements in the tdsrteye\modules\SerialAnalysis\waveforms directory.

To disable logging, select the [image] button.

Note: Use the [image] button to delete all the .wfm files in the selected directory.

See also:

File Names of Worst Case Waveforms

Log Worst Case Configure Options

Log Worst Case Configure Menu Parameters


Log Worst Case Configure Options


Log: Worst Case Configure Menu


File Names of Worst Case Waveforms

The application automatically names the files for you. The file names include the following information:

•	Type of measurement

•	Whether the file is a maximum or minimum value waveform

•	Date and time that the file was saved

File names appear after sequencing is complete and measurement results display.


Log: Worst Case File Names Menu


About Generating a Report

You can use the Report Generator utility to customize and generate a compliance report to view later or to share with others. The utility is independent from the RT-Eye application, yet is accessible from the application.

Note: The utility yields a .rpt file that can be viewed only from the Report Generator. You can select to export to an .rtf format file.

See also:

Starting the Report Generator and Accessing the Online Help

Setting Up a Test Template and Layout for a Report


Report Generator File Directories


Directory Structure for the Report Generator Utility


Starting the Report Generator and Accessing the Online Help

The online help for the Report Generator utility contains all the information you need to design and produce compliance report files. To start the report generator utility from the RT-Eye application and access the online help, follow these steps:

1.	Select Utilities> Reports.

2.	Select the Define Test Template or the Define Report Layout tab.

3.	Select the [image] command button.

4.	From the menu bar in the Report Generator window, select Help> Help Topics. The Help system for the utility appears.

You can refer to the online help topics for the Report Generator utility for information on how to do the following tasks:

•	Use an existing test template or report layout

•	Edit an existing test template or report layout

•	Create a new test template or report layout

•	Add Fields: Native, Oscilloscope, Serial Analysis

See also:

Setting Up a Test Template and Layout for a Report

Generating and Printing a Report


Setting Up a Test Template and Layout for a Report

The Report Generator utility allows you to design the contents and layout of a report that reflects your unique needs. In addition to a predefined template for each page, there is also a predefined report that includes all the predefined pages.

See also:

About Generating a Report

Starting the Report Generator and Accessing the Online Help

Generating and Printing a Report


Generating and Printing a Report

To generate and print a report, follow these steps:

1.	Select Utility> Reports.

2.	Select the [image] tab.

Do not touch the screen. Wait while the Report Generator creates the report. The oscilloscope fills the display while the application takes a screen print. When complete, the oscilloscope display shrinks to half size and automatically the RT-Eye application reappears.

The report displays when it is complete. You may need to use the Alt+Tab key combination to bring the Report Generator window to the front.

3.	You need to save the report to retain the file. To save the report, select File> Save from the menu bar of the Report Viewer. The report file is in a .rpt format and can only be viewed with the Report Viewer.

Later, you can use the Browse and View buttons in the Generate Report menu to open your saved report file.

4.	To use a different file, edit a file, or create a new report layout (or test template) file, refer to the Report Generator online help.

5.	To print the report, first verify that a printer is configured from the oscilloscope task bar.

6.	From the Report Generator menu in the RT-Eye application, select the [image] button.

You can also navigate to the saved file in the Report Generator window and send the file to a printer without having to open the file in the Report Viewer.

To share a report with others, you may want to generate a smaller file. To do so, refer to the Creating a PDF File of the Compliance Report topic.

7.	To export the report as an .rtf file, select File> Export to RTF from the menu bar of the Report Generator window. You can transfer the .rtf file to a personal computer, and view or print the file from a word processing program.

See also:

Test Template Menu

Report Layout Menu

Report Generate Menu Options

Report Generate Menu

Report Generate Menu Parameters

Report Fields


Creating a PDF File of the Compliance Report

You can send a report file to a "virtual" printer to create a smaller and more portable PDF file of your compliance report. To create a PDF file, follow these steps:

1.	Verify that a distiller program (for example, Adobe Acrobat Distiller 6.0) is configured from the oscilloscope task bar.

2.	From the Report Generator menu in the RT-Eye application, select the [image] button.

3.	Select the Distiller from the Printer Name selection menu.

4.	Send the report to the distiller (select OK).

5.	When the PDF file is complete, you can use other features of the distiller to further enhance the report, such as add watermarks if available.


Test Template Menu

Note: Refer to the online help topics for the Report Generator utility for information on how to create a new test template or on how to edit an existing test template.


Report Layout Menu

Note: Refer to the online help topics for the Report Generator utility for information on how to create a new report layout or how to edit an existing report layout.


Report Generate Menu Options


Report Generate Menu


Report Generator Fields

You can use the fields in the report generator utility to customize the contents and layout of a report. The utility has the following groups of fields:

•	Oscilloscope

•	Application

•	Native

See also:

Application Fields General Information List

Oscilloscope and Native Fields Lists


Application Fields General Information List

This is an example of the fields available for the general oscilloscope information in the report.

See also:

Application Fields Configuration List and Ref Levels Example

Application Fields Results List and Specific Measurements Example


Application Fields Configuration List and Ref Levels Example

This is an example of the fields available for the configuration information. This example also shows the expanded list of fields available for the Ref Levels in the report.


Application Fields Results List and Specific Measurements Example

This is an example of the fields available for the measurement results information. This example also shows the expanded list of fields available for an EyeWidth/Eye Height measurement and for a Rise Time measurement in the report.


Oscilloscope Fields and Native Fields Lists

This is an example of the fields available for the oscilloscope controls and other miscellaneous features in the report, such as lines.


Introduction to the Tutorial

This tutorial teaches you how to set up the application, take measurements, and view the results.

Before you begin the tutorial, you must do the following tasks:

Set up the oscilloscope

Starting the Application

Recall the tutorial waveform

Note: The screen captures shown are from a TDS7000 oscilloscope; there may be minor differences in the screens from other types of oscilloscopes.

See also:

Serial Analysis Laboratory (lab)


Setting Up the Oscilloscope

To set up the oscilloscope, follow these steps:

1.	In the oscilloscope menu bar, select File> Recall Default Setup to set the oscilloscope to the default factory settings.

2.	Press the individual CH1, CH2, CH3, and CH4 buttons as needed to remove active waveforms from the display.


Starting the Application

In the oscilloscope menu bar, select File> Run Application> RT-Eye Serial Compliance and Analysis. View how to start the application.

The application starts up and displays the Measurements Select menu.


Waveform Files

The application includes a waveform file to use with this tutorial. The file is from a PCE Express signal and is named RT-EyeTutorial.wfm.


Recalling a Waveform File

To recall a waveform file, follow these steps:

1.	In the oscilloscope menu bar, select File> Reference Waveforms> Reference Setup.

Ref1 is the default memory location to recall a waveform file. View the Oscilloscope Reference Memory Setup menu.

2.	Select the [image] button for Recall Ref1 from File.

3.	Navigate to the C:\TekApplications\ tds-rteye\examples\WFMs directory.

4.	Select the RT-EyeTutorial.wfm file and then [image].

The oscilloscope recalls the waveform file to reference memory and displays the waveform when the recall is complete.

5.	To return to the application, select the [image] button in the oscilloscope menu bar.


Oscilloscope Reference Memory Setup Menu


Taking an Eye Width Measurement

In this lesson, you will learn how to use the application to take an Eye Width/Eye Height measurement and view the results. This lesson teaches you how to do the following tasks:

•	Select a measurement

•	Configure a measurement

•	Take measurements

•	View the measurement results

•	View a Real-Time Eye diagram

•	Stop the application

•	Return to the application

To perform these lessons, the application must be installed and enabled on the oscilloscope. See Installation.


Setting Up an Eye Width Measurement

To set up the application to take an Eye Width/Eye Height measurement, follow these steps:

1.	To set the application to default values, select File> Recall Default.

The tutorial uses the default measurement and probe type. The measurement selections vary depending on the Probe Type option: Differential or Single Ended.

2.	Select the [image] button.

The Configure Source menu appears with tabs for other Configure menus,

.

3.	Select Ref1 as the source. View the waveform recalled to Ref1 and selected as the source.

4.	Select the [image] tab. The Configure Ref Levels Menu appears.

5.	Select the [image] command button. The application automatically calculates the appropriate reference voltage level values. View the reference voltage level values as calculated by the application.


 Ref1 Selected as the Source


Using Autoset for Reference Voltage Levels


Taking a Measurement and Viewing as an Eye Diagram

The default setup for the application includes an Eye Diagram plot. To take measurements and view the results as statistics and as a plot, follow these steps:

1.	Select the [image] command button in the Control Panel.

The application displays a real-time eye diagram that shows the characteristics of the waveform in a Plot Summary window. View the results of the Eye Width measurement as an Eye Diagram Plot.

2.	You can view details of the results and details of the plot. To do so, select the [image] command button in the Results Summary menu and the [image] in the Plot Summary window. View the details of the results and of the Eye diagram plot.

3.	You can use the Results Details: Select Measurement option to view details of other measurements.


Results Summary and Plots Summary Window Example


Results Details and Plot Details Window Example


Ending a Tutorial Lesson

If you need more than one session to complete the tutorial lessons, you can stop the tutorial and return to it later. Refer to Stopping the Tutorial and Returning to the Tutorial.

Note: The purpose of this tutorial is to familiarize you with the basic functions of the application, menus, and steps you may need to take if the quick method does not yield expected results.

See also:

Quick Method to Take Measurements

Serial Analysis Laboratory (lab)


Stopping the Tutorial

If you need more than one session to complete the tutorial lessons, you can stop the tutorial and return to it later.

To save the application setup and stop your session, refer to Saving a Setup File and to Exiting the Application.

See also:

Serial Analysis Laboratory (lab)


Returning to the Tutorial

To return to the tutorial setup, you can start the application and then recall the saved setup. To recall the application setup, refer to Recalling a Saved Setup File.


Quick Method Concept

There is a quick method you can use to take measurements that may yield reasonable results for your situation. The results from the quick method should indicate whether or not the setup is adequate. If it is not, then you can set up the application manually as shown in the first lesson.


Quick Method to Take Measurements

You can use the quick method to take measurements from channel (live) waveforms. To quickly take measurements, follow these steps:

1.	Start the application (also clears previous results), and make your Probe Type and measurement selections in the Measurements> Select menu.

2.	Select [image]. The Autoset Summary menu appears

3.	In the Autoset Summary menu, select [image].

The application calculates and applies appropriate settings for the vertical scale and horizontal resolution of the source and values for the reference voltage levels.

4.	If the values are acceptable, select [image].

If need be, select [image] to adjust the reference voltage levels in the Configure Ref Levels menu.

5.	Select the [image] command button to take measurements.

When sequencing is complete, the application displays statistical results and a real-time eye diagram that shows the characteristics of the waveform. View the results of the Eye Width measurement as an Eye Diagram.


Taking a TIE Jitter Measurement

In this lesson, you will learn how to use the application to take a TIE Jitter measurement on the waveform already recalled to the Ref1 location. This lesson teaches you how to do the following tasks:

•	View the results as a Histogram, and a Spectrum plot

•	Save statistical results to a .csv file

•	View a .csv file with Wordpad or in a spreadsheet

•	Generate a simple report


Clearing Results

Before taking more measurements, be sure to clear the results. To do so, select the [image] command button in the Control Panel.


Setting Up a TIE Jitter Measurement and Plots

To set up, take, and plot a TIE Jitter measurement, follow these steps:

1.	Clear any previous results.

2.	Select Measurements> Select and deselect the Eye Width/Eye Height measurement (from the previous lesson).

When you deselect a measurement, the application discards the corresponding options in the Plots menus.

3.	Select the [image] measurement.

The vertical scale, horizontal resolution and reference voltage levels were set for the source (Ref1) in the previous lesson.

4.	Select the [image] button.

5.	In the Select Subplot table, select TIE Jitter in the Measurement column and Histogram in the Plot Type column. Select the [image] command button.

The application displays the Results Summary menu and the Histogram plot. View the results of the TIE Jitter measurement.

6.	Select Plots> Select.

7.	In the second row of the Select Subplot table, select TIE Jitter in the Measurement column and Spectrum in the Plot Type column.

8.	Select [image] to update the plot window.


TIE Jitter Results with Histogram Example


TIE Jitter Histogram and Spectrum Plot Example


Examples of Plot Details

Here are details from the plots in this lesson.


Saving Statistical Results to a .CSV File

To save the statistical results to a .csv (comma separated variable) file, follow these steps:

1.	Select the [image] command button. The Save dialog appears.

2.	Use the [image] command button to select a directory in which to save the .csv file in.

3.	Enter a file name and select [image].

4.	Start the Wordpad program on the oscilloscope and select File> Open.

5.	Navigate and select the file you just created. View the .csv file with Wordpad.

6.	Close the Wordpad program.

7.	Copy the file to your PC, start a spreadsheet or other analysis program, and open the .csv file. You can customize the results to suit your analysis needs. View the .csv file as a spreadsheet.


A .CSV File Viewed with Wordpad Example
.CSV File Viewed with Wordpad Example


A .CSV File Viewed in a Spreadsheet Example
.CSV File Viewed in a Spreadsheet Example


Generating a Simple Report

To generate a simple report, follow these steps:

1.	Select Utilities> Report.

The Report Generator menu appears and is set to use the default Define Test Template and Define Report Layout definitions.

2.	Select the [image] command button.

The application generates and displays the report. View the simple report.

3.	To print the report, select the [image] command button.

Note: Before the application can send the file to a printer, you need to check if the printer is set up from the Start menu (in the oscilloscope task bar).


Simple Report Example Page 1


Simple Report Example Page 2


About Measurement Algorithms

The RT-Eye application can take measurements from one or two serial data waveforms. The number of waveforms used by the application depends on the probe selected in the Probe Type option of the Measurements> Select menu.

 The Algorithms book includes Field Notes that you may use to ensure good measurement results.

See also:

Measurements

Oscilloscope Setup Guidelines

Test Methodology


Measurements


Oscilloscope Setup Guidelines

For all measurements, use the following guidelines to set up the oscilloscope:

1.	The signal is any channel, reference, or math waveform.

2.	The vertical scale for the waveform must be set so that the waveform does not exceed the vertical range of the oscilloscope.

3.	The sample rate must be set small enough to capture sufficient waveform detail and avoid aliasing.

4.	Longer record lengths increase measurement accuracy (though at the same time decrease measurement speed).


Test Methodology

The application performs the measurement according to the following steps:

1.	Imports the current waveform.

2.	For timing measurements, checks that there are a minimum number of edges in the waveform to calculate the measurement as follows:

•	Single edge: Rise Time, Fall Time

•	Two cycle-start edges: Unit Interval

•	Three cycle-start edges: TIE

•	Jitter measurements require at least 50 pattern repeats for RjDj analysis; accuracy may be degraded for fewer than 100 pattern repeats

•	Two edges on each of two waveforms: Differential Skew

3.	Performs the measurement.

4.	Displays the results as statistics where you can save the results to a .csv file.

5.	Displays the results as a plot if defined and enabled.


About Notation in Algorithms

All measurements are made on one of several voltage waveforms. Timing measurements are based on edge locations in the waveform or on clock edge times derived from the waveform edge locations. Amplitude measurements are made on the entire waveform or on waveform values based on recovered clock times. To represent measurements as formulas, the algorithm descriptions follow notational rules.

See also:

Notational Rules


Notational Rules


Summary Definitions of Fundamental Signals and Measurements

The next several topics list the annotation of the signals and measurements as they appear in the algorithm specific to each measurement. The algorithms comprise the following types of annotation:

•	Waveforms

•	Edge Time Threshold Voltages

•	Crossing Times

•	Recovered Clock Times

•	Eye Center Voltages


Waveforms


Edge Time Threshold Voltages

See also:

About Reference Voltage Levels


Crossing Times

See also:

Edge Time Threshold Voltages


Recovered Clock Times

See also:

Configuring Clock Recovery Methods

Configure Jitter Methods


Eye Center Voltages

See also:

Recovered Clock Times


About Timing Measurements

Timing measurements are all based on either Crossing Times or Recovered Clock Times. Crossing times are dependent on Ref Level thresholds. Recovered Clock Times are affected by the clock recovery method specified in Clock Recovery and Jitter Configuration.

See also:

Crossing Times

Recovered Clock Times

Edge Time Threshold Voltages

Configuring Clock Recovery Methods

Configure Jitter Methods


Eye Width Measurement

The Eye Width measurement is the measured minimum horizontal eye opening at the zero reference level as shown in the eye diagram.

Where:

 is the average UI

 is the Peak-Peak TIE

See also:

Unit Interval Measurement

TIE Jitter Measurement


Rise Time Measurement

The Rise Time measurement is the time difference between when the [image] reference level is crossed and the [image] reference level is crossed on the rising edge of the waveform.

Where:

 is a Rise Time measurement

 is a set of [image] for rising edges only

 is a set of [image] for rising edges only

i and j are indexes for nearest adjacent pairs of [image] and [image].

n is the index of rising edges in the waveform

Rise time can be limited to only rising edges of consecutive transitions in the File Preferences menu. In the PCI-Express module, Rise Time is taken independently on each single-ended waveform sources when you use two single-ended probes as the signal source.

Rise Time for [image] is as follows:

and for

See also:

Crossing Times

File Preferences Menu


Fall Time Measurement

The Fall Time measurement is the time difference between when the [image] reference level is crossed and the [image] reference level is crossed on the falling edge of the waveform.

Where:

 is a Fall Time measurement

 is a set of [image] for falling edges only

 is a set of [image] for falling edges only

i and j are indexes for nearest adjacent pairs of [image] and

n is the index of falling edges in the waveform

Fall time can be limited to only falling edges of consecutive transitions in the File Preferences menu. In the PCI-Express module, Fall Time is taken independently on each single-ended waveform source when you use two single-ended probes as the signal source.

Fall Time for [image] is as follows:

and for

See also:

Crossing Times

File Preferences Menu


Rising Edge Measurement

The Rising Edge measurement or Rising Edge Rate measurement is defined as the ratio of voltage difference between [image] and [image] to the time difference between the crossing of [image] reference level and the crossing of [image] reference level on the rising edge of the waveform.

Where:

 is a rising edge rate measurement

 is a predefined high voltage reference level

 is a predefined low voltage reference level

 is a set of  time when [image] reference level is crossed on rising edges

 is a set of  time when [image] reference level is crossed on rising edges

i and j are indexes for nearest adjacent pairs of [image] and [image].

n is the index of rising edges in the waveform

The rising edge measurement is required for reference clock measurements in PCI-Express and FB-DIMM modules. In these two modules, rising edge is taken on differential signal, the value of [image] and [image] is specified as 150mV and -150mV respectively as shown in the following diagram.

 See also:

 Crossing Times


Falling Edge Measurement

The Falling Edge measurement or Falling Edge Rate measurement is defined as the ratio of voltage difference between [image] and [image] to the time difference between the crossing of [image] reference level and the crossing of [image] reference level on the falling edge of the waveform.

Where:

 is a falling edge rate measurement

 is a predefined high voltage reference level

 is a predefined low voltage reference level

 is a set of  time when [image] reference level is crossed on falling edges

 is a set of  time when [image] reference level is crossed on falling edges

i and j are indexes for nearest adjacent pairs of [image] and

n is the index of falling edges in the waveform

The falling edge measurement is required for reference clock measurements in PCI-Express and FB-DIMM modules. In these two modules, falling edge is taken on differential signal, the value of [image] and [image] is specified as 150mV and -150mV respectively as shown in the Rising Edge Measurement diagram.

See also:

Crossing Times

Rising Edge Measurement


Unit Interval Measurement

The Unit Interval measurement calculates the cycle duration of the recovered clock.

Where:

 is a recovered clock edge

n is the index to UI in the waveform

See also:

Recovered Clock Times


Bit Rate Measurement

The Bit Rate measurement calculates the baud (such as frequency) of the recovered clock.

BR(n) = 1/UI(n)

Where:

UI is the associated Unit Interval measurement

n is the index to UI in the waveform

See also:

Recovered Clock Times

Unit Interval Measurement


Differential Skew Measurement

The Skew measurement is the time delay between the two single-ended waveform sources.

Where:

 is the Skew measurement

 is the mid level crossing time of

 is the mid level crossing time of

n is the index to edges in the waveform

See also:

Crossing Times


About Amplitude Measurements

Some amplitude measurements can be limited to only the high or only the low amplitude of consecutive transitions in the File Preferences menu.


Eye Height Measurement

The Eye Height measurement is the measured minimum vertical eye opening at the UI center as shown in the plot of the eye diagram. There are three types of Eye Height values.

Eye Height:

Where:

 is the minimum of the High voltage at mid UI

 is the maximum of the Low voltage at mid UI

Eye Height – Transition:

Where:

 is the minimum of the High transition bit eye voltage at mid UI

 is the maximum of the Low transition bit eye voltage at mid UI

Eye Height – Non-Transition:

Where:

 is the minimum of the High non-transition bit eye voltage at mid UI

 is the maximum of the Low non-transition bit eye voltage at

 mid UI

See also:

Eye Center Voltages


Differential Amplitude Measurement

The Differential Amplitude measurement calculates the change in voltage level across a transition in the differential waveform.

Where

n is the index of transitions of interest

i is the index of UI (bit) locations preceding/following the transition

 is the state level of the unit interval (bit period)

Where

j is the sample index; in the previous equation, j spans the samples that fall in the center 30% of UIs i or i+1.

 is the differential voltage.

Note: Eligible transitions are all transitions (Blue and Red) or consecutive transitions (Red only). This is set in the File Preferences menu.

See also:

File: Preferences Menu


Differential Peak Voltage Measurement

The Differential Peak Voltage measurement returns two times the larger of the Min or Max statistic of the differential voltage waveform.

Where:

i is the index of all waveform values

 is the Differential voltage signal

See also:

Waveforms


Differential Average Measurement

The Differential Average measurement returns the Mean of the differential voltage waveform.

Where:

i is the index of all waveform values

 is the Differential voltage signal

See also:

Waveforms


High Amplitude Measurement

The High Amplitude measurement calculates the mode of all differential waveform values greater than zero.

Where:

 is Differential voltage signal

i is the index of all waveform values

See also:

Waveforms


Low Amplitude Measurement

The Low Amplitude measurement calculates the mode of all differential waveform values less than zero.

Where:

 is Differential voltage signal

i is the index of all waveform values

See also:

Waveforms


CM Voltage Measurement

The Common Mode Voltage measurement (also called DC Common Mode) calculates the mean of the Common Mode voltage waveform.

Where:

 is the Common Mode voltage signal

 is the Common Mode voltage signal

i is the index of Common Mode waveform values

See also:

Waveforms


AC CM Voltage Measurement

The AC Common Mode Voltage measurement calculates the AC statistics of the Common Mode voltage waveform with the DC value removed.

Where:

i is the index of all waveform values

 is the AC Common Mode voltage signal

 is the Common Mode voltage signal

 is the DC Common Mode voltage signal

See also:

Waveforms

CM Voltage Measurement


AC CM RMS Voltage Measurement

The AC Common Mode RMS Voltage measurement calculates the RMS statistic of the Common Mode voltage waveform with the DC Value removed.

Where:

i is the index of all waveform values

 is the RMS of the AC Common Mode voltage signal

 is the AC Common Mode voltage signal

See also:

Waveforms

CM Voltage Measurement

AC CM Voltage Measurement


De-Emphasis Measurement

The De-Emphasis measurement calculates the ration of any non-transition eye voltage (2nd, 3rd, etc. eye voltage succeeding an edge) to its nearest preceding transition eye voltage (1st eye voltage succeeding an edge). In the accompanying diagram, it is the ratio of the Black voltages over the Blue voltages. The results are given in dB.

or

Where:

 is the High voltage at mid UI following a positive transition

 is the Low voltage at mid UI following a negative transition

 is the High voltage at mid UI following a positive transition bit

 is the Low voltage at mid UI following a negative transition bit

m is the index for all non-transition UIs

n is the index for the nearest transition UI preceding the UI specified by m

See also:

Eye Center Voltages


About Jitter Measurements

In the context of this RT-Eye analysis package, the term Jitter is used solely in relation to timing errors between data signal edges and recovered clocks. The two measurements in this category are TIE Jitter and Jitter @ BER. TIE Jitter is a direct measurement of the time difference (error) between data edges and associated clock edges, which is recovered from the data signal edges. Jitter @ BER is the label for Random and Deterministic Jitter analysis (Rj/Dj) on a TIE Jitter measurement.

The purpose of the Rj/Dj analysis is two fold: to decompose the TIE into component elements and to extrapolate jitter measurements (Total Jitter or Eye Opening) @ BERs that would require very large data sets for direct measurement.

TIE, and therefore Jitter @ BER, correlates to Eye Diagram statistics. A time Histogram at the eye crossing (at the mid reference voltage level) is the same as Histogram Plot of the TIE Jitter measurement on the same signal.

The method of clock recovery has a big impact on Jitter results.

See also:

Configuring Clock Recovery Methods

Configure Jitter Methods

Recovered Clock Times


Jitter @ BER Measurement

The Rj/Dj measurement calculates the deterministic and random components of jitter. The jitter is obtained from the TIE measurements. Rj is the random jitter and is assumed to be Gaussian having flat spectrum. The Rj measurement calculates the RMS value of the random jitter.

Dj is the deterministic jitter. It is predictable and can be generated consistently under known circumstances. Dj has a spectrum of impulses when the data signal has a repeating pattern. The Dj measurement calculates the peak-to-peak value of the deterministic jitter. Tj is the total jitter, which is composed of Dj and Rj. The Tj measurement calculates the peak-to-peak value of the total jitter at the specified BER.

Dj comes from multiple sources:

•	Periodic jitter (PJ) from periodic interference that is not correlated to the data

•	Data dependent jitter (DDJ) from interference of nearby edges (also called ISI or Inter-Symbol Interference)

•	Duty Cycle Distortion jitter (DCD) from slew rate differenced between rising and falling edges.

Two methods of jitter measurements are supported. The first method is a spectrum analysis based approach (default) when the data pattern is repetitive. A clock waveform is always repetitive. Other repetitive testing data patterns are used, such as the CJTPAT data pattern.

The second method is Rj/Dj separation method is arbitrary pattern analysis based approach when the data pattern is not necessarily repetitive. It is useful for long PRBS data patterns. The data is virtually non-repetitive within a single acquisition for extremely long data pattern.

See Also:

TIE jitter Measurement

Spectrum Analysis Based Rj/Dj Separation on Repeating Pattern

Arbitrary Pattern Analysis based Rj/Dj Separation

Rj/Dj Separation based on Dual Dirac Model

Bathtub Curve: BER versus Decision Time


Spectrum Analysis based Rj/Dj Separation on Repeating Pattern

Dj components can be identified in a jitter spectrum under a set of conditions. PJ will appear as spectral impulses regardless of the conditions. DDJ and DCD will appear as spectral impulses provided that the data signal is a repeating pattern. The frequencies of DDJ and DCD spectral impulses are at harmonics of the (Bit Rate / Pattern length). The remaining spectral energy is attributed to Rj. Dj components are spectrally separated from Rj.

The Dj measurement is the peak-to-peak value of the inverse fourier transform of the deterministic jitter spectral components. Tj is the total jitter, which is composed of Dj and Rj. The Tj measurement calculates the peak-to-peak value of the total jitter. Rj is assumed to be near Gaussian. The Rj measurement is the calculated RMS value of random jitter.

A Jitter PDF is formed by convolving Gaussian distribution of Rj and Histograms of Dj. A Bathtub curve is calculated from the left and right side CDFs of the Jitter PDF. The Bathtub curve will yield TJ and Eye Opening ( [image]). View the Bathtub Curve: BER versus Decision Time Diagram.

The application calculates the measurements using the following equation:

Where:

 is the Deterministic jitter

 is the Random jitter

 is the Total jitter

 is the PDF of the Total jitter

 is the minimum value at the Bathtub curve at a given BER

 is the maximum value at the Bathtub curve at a given BER

 is the is the time domain record of the [image] component of jitter obtained by performing an inverse FFT of the [image] components of the TIE spectrum.

 is the time domain record of measured TIE jitter.

Additionally, [image] is further decomposed as follows:

Where:

 is the periodic jitter

 is the duty cycle jitter

 is the data dependent (or ISI) jitter

 is the time domain record of the [image] component of jitter obtained by performing an inverse FFT of the [image] components of the TIE spectrum.

 is the time domain record of the [image] + [image] component of jitter  obtained by performing an inverse FFT of the [image] + [image] components of the TIE spectrum.

 is [image] on rising edges only.

 is [image] on falling edges only.

See Also:

Jitter @ BER Measurement

Arbitrary Pattern Analysis based Rj/Dj Separation

Rj/Dj Separation based on Dual-Dirac Model

Bathtub Curve: BER versus Decision Curve


Arbitrary Pattern Analysis based Rj/Dj Separation

When the data pattern is non-repeating, Pj still has a spectrum of impulses while DCD+DDJ no longer has a spectrum of impulses. Therefore, Dj no longer has a spectrum of impulses.

The DCD+DDJ value is obtained through the arbitrary data pattern analysis method, which is based on the assumption that any given bit is affected by a finite number of preceding bits. By averaging all events where the current bit is preceded by a particular bit sequence, for example, the current bit is preceded by the bit sequence 1001101, the DCD+DDJ with such a pattern is obtained because PJ and RJ are not correlated to a particular data sequence and thus are averaged out.

If each bit is assumed to be affected by N preceding bits, there are a total of 2N possible data sequences. The sequence length N is a configurable parameter. To get statistically sound average values, a population limit is the other configurable parameter that prevents using an average value without enough population. Only DCD+DDJ values obtained from data sequences with a population above the limit are used to calculate DCD+DDJ values.

After each edge is associated with a DCD+DDJ value, with known total jitter, the PJ+Rj value for each bit is then obtained by subtracting DCD+DDJ from TJ.

Separation of DDJ and DCD from DCD+DDJ is the same as that in the spectrum based Rj/Dj separation method.

PJ and Rj are then separated from PJ+Rj using the spectrum analysis method. PJ has a spectrum of impulses. Rj has a flat spectrum. Not all of the edges DCD+DDJ can be determined because of their associated data sequences, which have low populations and are treated as if there are no edges when performing PJ and Rj separation.

The histogram of Dj is a convolution of the histogram of DCD+DDJ and the histogram of PJ.

All other aspects of the arbitrary pattern analysis based Rj/Dj separation are the same as those of the spectrum analysis based Rj/Dj separation.

See Also:

Spectrum Analysis based Rj/Dj Separation on Repeating Pattern

Jitter @ BER Measurement

Rj/Dj Separation based on Dual-Dirac Model

Bathtub Curve: BER versus Decision Time


Rj/Dj Separation Based on Dual Dirac Model
Rj/Dj Separation based on Dual-Dirac Model

The Dual-Dirac model based Rj/Dj separation method fits the Bathtub curve to a theoretical model of Rj and Dj where Rj has a Gaussian distribution and Dj has a distribution of two Dirac impulses with the same height. Curve fitting at different BER levels in Bathtub curve yields the standard deviation value of Rj and peak-to-peak value of Dj. The Bathtub curve is obtained from the spectrum analysis based or the arbitrary pattern analysis based Rj/Dj separation methods.  Rj and Dj based on the Dual-Dirac model can be denoted as [image] and [image].

After [image] and [image] are obtained, Tj can be calculated using this formula:

Where Q is the function of BER that has a value of about 7 when [image]. The Eye opening is computed in the same way as it is computed in the spectrum analysis based Rj/Dj separation.

The Dual Dirac model based Rj/Dj separation method is used in PCI-Express and FB-DIMM modules.

Dj does not usually have a pure Dual-Dirac distribution. So the value of [image] is often greater than the value of Rj obtained from the spectrum analysis based or the arbitrary pattern analysis based Rj/Dj separation. The value of [image] is often less than that of Dj.

Refer to www.T11.org for a detailed description of Rj/Dj separation based on Dual-Dirac model.

See Also:

Jitter @ BER Measurement

Spectrum Analysis based Rj/Dj Separation on Repeating Pattern

Arbitrary Pattern Analysis based Rj/Dj Separation

Bathtub Curve: BER versus Decision Time


Jitter Measurements Field Notes

Data pattern generation techniques vary from one serial data standard to another. Refer to the Standards Methods Of Implementation (MOIs) documents for specific details on how to set up those system-to-broadcast testable data/test patterns.

Both PCI Express and InfiniBand serial data traffic test patterns are interspersed with Skip Ordered Sets (SOSs) on regular intervals. When conducting jitter measurements that require repeated data sets (such as for Jitter @ BER), you will need to set up the acquisition system to acquire between these non-deterministic Skip Characters. Refer to the Standards MOIs documents for specific details on how to set up the system to work under these conditions.


TIE Jitter Measurement

The measured time difference between a data edge and a recovered clock edge.

Where:

 is the original data edge

 is the recovered data edge (for example, the recovered clock edge corresponding to the UI boundary of

n is the index of all edges in the waveform

See also:

Recovered Clock Times


TIE Jitter Filtering Measurement

TIE Jitter Filtering measurement is used to apply a pre-defined filter to TIE jitter to get filtered TIE jitter measurement.

Where:

 is the frequency domain representation of a filtered TIE jitter

 is the transfer function of a pre-defined filter

 is the frequency domain representation of a TIE jitter before filtering

The TIE jitter filtering measurement is required by PCI-Express and FB-DIMM modules for reference clock measurements. In these two modules, the filter is used to emulate the effects of variation of the jitter transfer function of PLLs between transmitters and receivers; transport delays between them; differences in the propagation delays in the devices, and the phase tracking bandwidth of the clock phase recovery circuitry. One such transfer function [image] is defined as

Where the parameters [image], [image] and [image] are pre-defined. An H(s) has a magnitude frequency response as follows:

See Also:

TIE Jitter Measurement


About Statistics

The application calculates statistics for all selected measurements. The application displays the following statistics in the Results menus:

•	Maximum value

•	Minimum value

•	Mean value

•	Standard deviation value

•	Peak-Peak value

•	Population


Maximum Value

The application calculates this statistic using the following equation:


Minimum Value

The application calculates this statistic using the following equation:


Mean Value

The application calculates this statistic using the following equation:


Standard Deviation Value

It may seem odd that the equation for the estimate of the Standard Deviation contains a 1/(N-1) scaling factor. If you knew the true mean of X and used in place of the estimated mean [image], then you would, in fact, scale by1/N. But, [image] is an estimate and is likely to be in error (or bias), causing the estimate of the Standard Deviation to be too small I scaled by 1/N. This is the reason for the scaling shown in the equation. (Refer to Chapter 9.2 in A. Papoulis, Probability, Random Variables, and Stochastic Processes, McGraw Hill, 1991.)

The application calculates this statistic using the following equation:


Peak-to-Peak Value

The application calculates this statistic using the following equation:


Population Value

Population is the total number of data points applied to the displayed statistics.


About the GPIB Program

An example of a GPIB program that can execute the RT-Eye application is included with the application. The oscilloscope hard disk includes the example file, rt-eyectrl.c. On the hard drive, the file resides in the C:\TekApplications\tdsrt-eye\Examples\RemoteCtrl directory.

The example shows how a GPIB program executes the application to do the following tasks:

•	Start the application

•	Recall a setup

•	Take a measurement

•	Check for an error

•	Exit the application

See also:

Guidelines to GPIB Program

Introduction to GPIB Command Syntax

GPIB Reference Materials


Guidelines to GPIB Programming

The application includes an example file of a GPIB program. Your GPIB program should comply with the following guidelines:

•	The application startup must complete before sending additional GPIB commands to the application; query the variable application; it will return "TDSRT-EYE" when the application startup is complete

•	Recall a setup file from GPIB to select measurements and set up the application

•	The measurements cycle must complete before data is queried; query the variable SequencerState; it will return "Ready" when sequencing is complete

•	The resultFor and resultAcq variables must be set before querying results; pause a second after setting each variable

•	The error variable should be checked to ensure that an error has not occurred because of a measurement command problem; the measError variable returns errors specific to the measurement selected by resultFor

See also:

Introduction to GPIB Command Syntax

GPIB Reference Materials

Variable:Value RT-Eye Command

Measurements Results Queries


Program Example

The program example shows how to communicate to the RT-Eye application using remote GPIB commands. The program includes the following steps:

1.	Start up the application

2.	Recall a setup

3.	Take a measurement

4.	Display results or errors

5.	Exit the application

In the example, you will recall a setup file named rt-eyectrl.c (setup). You can use the File> Save function in the application to save setup files according to your own needs.

See also:

Guidelines to GPIB Programming


Introduction to GPIB Command Syntax

With knowledge of the GPIB command syntax, you can design a GPIB program to do the following tasks:

•	Start the RT-Eye application

•	Recognize an active application with GPIB protocol

•	Program and read application setup parameters

•	Sequence measurements

•	Read measurement results

•	Generate reports

See also:

Guidelines to GPIB Programming

GPIB Reference Materials

Starting and Setting Up the Application

Variable:Value RT-Eye Command

Measurements Results Queries


GPIB Reference Materials

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

•	The rt-eyectrl.c file on the oscilloscope hard drive (located in the c:\TekApplications\tdsrt-eye\Examples\RemoteCtrl directory) for an example of a GPIB program that can execute the application

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

•	The Parameters topics for range of values, minimum units and default values of parameters

•	The programmer information in the online help of your oscilloscope

See also:

Starting and Setting Up the Application Using GPIB


Starting and Setting Up the Application using GPIB

To start the RT-Eye application, you must send the oscilloscope the following GPIB command:

application:activate "RT-Eye Serial Compliance and Analysis"

Note: The name of the application in the previous string is identical to the name of the application from the oscilloscope Run Application list.

The application uses the GPIB VARIABLE:VALUE command with arguments to execute some features. The set of GPIB commands does not include the variable names and variable values necessary to select and configure the measurements in the GPIB program.

You must manually set up the application and oscilloscope, selecting and configuring the measurements that you want to use with your GPIB program, and save them in a setup file in the default setup folder for that module. To save a setup file, refer to Saving a Setup File.  Use the name of the saved setup file as the value for the "recallName" variables in your GPIB program.

See also:

GPIB Reference Materials

Variable:Value RT-Eye Command

Measurements Results Queries


Variable: Value RT-Eye Command

Description

This command accepts string arguments for a control or data variable and a value to which to set the argument.

Syntax

VARIABLE:VALUE "<variable name>","<variable value>"

Note: The arguments <variable name> and <variable value> are required in the order indicated.

VARIABLE:VALUE? <variable name> for query.

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

See also:

Variable:Value RT-Eye Command Arguments and Queries (Part 1)

Variable:Value RT-Eye Command Arguments and Queries (Part 2)

Measurements Results Queries

GPIB Commands Error Codes

Program Example


Variable: Value RT-Eye Command Arguments and Queries (Part 1)


Variable:Value RT-Eye Command Arguments and Queries (Part 2)


Measurements Results Queries

 CAUTION: Before you query for the measurement results, be sure to insert a one second delay after the resultFor and the resultAcq commands to allow the statistics variables to refresh.

You need to use the VARIABLE:VALUE? form to enter measurement results queries in your GPIB program. Before you can do this, you must first set the measurement with the resultFor command. You can select the current or all acquisition statistics with the resultAcq command.

The next several tables list the measurement results queries for the measurement selected in the resultFor variable.

See also:

Variable:Value RT-Eye Command

Measurements Results Queries Variable Names (Part 1)

Measurements Results Queries Variable Names (Part 2)

Serial Analysis Measurement Names for the resultFor Variable

InfiniBand Driver Measurement Names for the resultFor Variable

InfiniBand Receiver Measurement Names for the resultFor Variable

InfiniBand Cable Assembly Measurement Names for the resultsFor Variable

PCI Express Driver Measurement Names for the resultFor Variable


Measurements Results Queries Variable Names (Part 1)

See also:

Measurements Results Queries


Measurements Results Queries Variable Names (Part 2)

See also:

Measurements Results Queries


Serial Analysis Measurement Names for the resultFor Variable

See also:

Measurements Results Queries


InfiniBand Driver Measurement Names for the resultFor Variable

See also:

Measurements Results Queries


InfiniBand Receiver Measurement Names for the resultFor Variable

See also:

Measurements Results Queries


InfiniBand Cable Assembly Measurement Names for the resultsFor Variable

See also:

Measurements Results Queries


PCI Express Driver Measurement Names for the resultFor Variable
PCI Express Measurement Names for the resultFor Variable for any Test point except Reference clock

See also:

Measurements Results Queries


PCI Express Reference Clock Measurement Names for the resultFor Variable

See Also:

Measurements Results Queries


FBDIMM Transmitter Measurement Names for the resultFor Variable

See Also:

Measurements Results Queries


FBDIMM Receiver Measurement Names for the resultFor Variable

See Also:

Measurements Results Queries


FBDIMM Reference Clock Measurement Names for the resultFor Variable

Note: All measurements are available only for differential probe.

See Also:

Measurements Results Queries


GPIB Commands Error Codes

See also:

GPIB Commands Warning Codes


GPIB Commands Warning Codes

See also:

GPIB Commands Error Codes


About Application Parameters

This section describes the RT-Eye application parameters and includes the menu default settings. Refer to the user manual for your oscilloscope for operating details of other controls, such as front-panel buttons.

The parameter tables list the selections or range of values available for each option, the incremental unit of numeric values, and the default selection or value.

Refer to the GPIB topics for a complete list of the GPIB Command Syntax. The topics include a complete list of the GPIB commands along with the arguments, variables, and variable values that correspond to the RT-Eye parameters.

Note: Unit values shown are valid when the FINE button is enabled on the oscilloscope.

See also:

Related Documentation

GPIB Reference Materials


File Menus Parameters

The File drop-down list includes the following command buttons:

•	Recall Default

•	Minimize

•	Exit

See also:

Application Directories and Usage


File Preferences Menu Parameters

The File Preferences menu includes the following command buttons:

•	 Cancel

•	OK


Control Panel Parameters

The Control Panel menu includes the following command buttons:

•	Start

•	Stop

•	Clear Results


Measurements Select Menu Parameters

Available measurements in the Measurements Select menu are dependant on the selection for the Probe Type option. Measurements available by area are as follows:

•	Timing area: Rise Time, Fall Time, Unit Interval, Bit Rate, Eye Height, Eye Width, and Differential Skew

•	Amplitude area: Differential Voltage, High Amplitude, Low Amplitude, CM Voltage, AC CM Voltage, and De-Emphasis

•	Jitter area: Jitter@BER and TIE Jitter

Note: The Differential Skew, CM Voltage, and AC CM Voltage measurements are added when you select Single Ended as the Probe Type option.

See also:

Measurement Definitions


Autoset Summary Menu Parameters

The Autoset Summary menu includes the following command buttons:

•	Autoset

•	Configure

•	Close


Measurements Configure Menus

The application includes the following Measurements Configure menus:

•	Source for Single Ended Probes or Source for Differential Probes

•	Ref Levels

•	Smart Gating

•	Clock Recovery

•	Jitter Method

•	Population

•	General Config

Note: These menus are generally referred to as the Configure menus.

The application automatically calculates parameters for reference voltage levels in the Ref Level Autoset Setup menu. Display the Ref Level Autoset Setup menu parameters.


Configure Source Menu Parameters for Differential Probes

The Configure Source menu includes the following command buttons in the Autoset area:

•	Vertical Scale

•	Horizontal Resolution

•	Vertical & Horizontal

See also:

Application Directories and Usage


Configure Source Menu Parameters for Single-Ended Probes

The Configure Source menu includes the following command buttons in the Autoset area:

•	Vertical Scale

•	Horizontal Resolution

•	Vertical & Horizontal

See also:

Application Directories and Usage


Configure Ref Levels Menu Parameters

The Configure Ref Levels menu includes the following command buttons in the Autoset area:

•	Setup

•	Run


Configure Ref Level Autoset Setup Menu Parameters

The Configure Ref Level Autoset Setup menu includes the following command buttons:

•	OK

•	Cancel


Configure Smart Gating Menu Parameters

See also:

Configure Smart Gating Menu with Smart Gating Parameters


Configure Smart Gating Menu with Custom Parameters
Configure Smart Gating Menu with Smart Gating Parameters

The value that displays under Stop shows the sum of the Length and Start options.


Configure Clock Recovery Menu Parameters


Configure Jitter Menu Parameters

See also:

Clock Recovery Method Diagram


Configure Population Menu Parameters


Configure General Config Parameters


Measurements Limits Menu Parameters

See also:

Application Directories and Usage


Results Menus

The application includes the following Results Menus:

•	Summary

•	Details


Results Summary Menu Parameters

The Results Summary menu includes the following command buttons:

•	Show Plot

•	Export to CSV


Results Details Menu Parameters

The Results Details menu includes the following command buttons:

•	Show Plot

•	Export to CSV


Plots Select Menu Parameters

The Plots Select menu includes the following command button:

•	Refresh

See also:

Measurements and Available Plots


Eye Diagram Configure Menu Parameters

See also:

Using User Masks


Histogram Plot Configure Menu Parameters


Spectrum Plot Configure Menu Parameters


Bathtub Plot Configure Menu Parameter


Log Worst Case Configure Menu Parameters

The Log Worst Case menu includes the following command button:

•	Purge

See also:

Application Directories and Usage


Utilities Report Generator Menus Parameters

There are no parameters for the Report Generator utility menus.


Help Menu

There are no parameters for the Help menu.


About the Serial Analysis Laboratory (Lab)

The Serial Analysis Laboratory presents a typical application example that highlights the compliance and analysis capabilities of the RT-Eye application, and will give you ideas on how to use the application to solve your own test problems. This lab covers and explores the following areas:

•	Using the Serial Data Wizard to perform serial analysis on a 2.5 Gb/s serial bit stream

•	Performing jitter measurements that are compliant to the T11.2 MJSQ using the spectrum approach to jitter analysis

•	Saving and using MyTest

•	Creating Limits Module File for custom Compliance Test

•	Creating a Compliance Report

•	Performing a PCI Express Compliance test (PCI Express Compliance Module required)

Note: To use this lab, you must have the RT-Eye application installed, enabled and running on the oscilloscope. For information, see Installation and Starting the application.

Requirements:

•	TDS/CSA7000 series oscilloscope (1.5 GHz and above) or TDS6000 series oscilloscope if you use a reference waveform.

Optionally, the Training Board 2 (P/N 020-2460-00) or Training Board 3 by Tektronix. A minimum bandwidth of 4 GHz is required for a live signal.

•	RT-Eye Serial Data Compliance and Analysis software (Opt. RTE)

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 simultaneously display these lab exercises in the second monitor, the waveform (or a plot) on the oscilloscope, and the RT-Eye measurement results for easy viewing.


Recall Default Settings and Run RT-Eye SW

To ensure that your lab results match the results shown in these lab exercises, you will recall the default settings to the oscilloscope and to the RT-Eye application. To do so, follow these steps:

•	Push the DEFAULT SETUP front-panel button to start from a known setup.

•	From the oscilloscope application menu, select File> Run Application> RT-Eye Serial Compliance and Analysis on non-B models, or Applications > RT-Eye Serial Compliance and Analysis on B/C models

Will you be using a Reference Waveform File or a live signal from the Training Board?


Reference Waveform File Setup

This lab uses a 2.5 Gb/s differential signal saved to

C:\TekApplications\tds- rteye\modules\SerialAnalysis\waveforms\examples\2_5Gbps_PRBS.wfm.

You can recall the waveform to reference memory, view the waveform, and analyze it with any RT-Eye compliance and analysis application. To recall the waveform file to reference memory, follow these steps:

1.	Click the DEFAULT SETUP button on the front panel.

2.	Push the CH1 front-panel button to turn off the Channel 1 waveform Push the CH1 front-panel button to turn off the Channel 1 waveform.

3.	From the Oscilloscope application menu, select Reference Waveforms> Recall Wfm

4.	Select Recall Ref1 from Wfm File

5.	Browse to and select: C:\TekApplications\tdsrteye\modules\SerialAnalysis\waveforms\examples\2_5Gbps_PRBS.wfm as the waveform file.

6.	Use the Zoom control to zoom in and view individual bits.

7.	Select Measurement> Wizard, to run the Serial Data Wizard.

8.	Make Wizard Selections as shown in the yellow text in the following figure.

9.	Proceed to Run the Analysis and View the Results.


Training Board 2 - Live Signal Source

You can use the Training Board 2 or Training Board 3 to work through these exercises. To do so, use the 2.5 Gb/s PRBS signal. This signal has rise times of <100 ps, and thus needs full sample rate (20 GS/s) to perform measurements accurately. You can use the following configurations:

•	TDS7000 Series (TDS7404): Use P7380SMA with CH1 as the Differential Source for Analysis.

•	TDS6000 Series: Use P7380SMA with CH1 as the Differential Source for Analysis or Use TCA-SMA Adapters on CH1 and CH3 as Single-Ended Sources for Analysis.


Use P7380SMA with CH1 as the Differential Source for Analysis

1.	Use the phase-matched SMA cables (provided with the P7380SMA probe) to connect the positive and negative leg of the 2.5Gb/s signal on the training board and CH 1 on the oscilloscope.

2.	Connect the other end of the phase-matched cables to the "D+" and "D-" connections of the P7380SMA probe input.

3.	Connect the TekConnect end of the P7380SMA probe to CH1 of the oscilloscope.

4.	Push the AUTOSET front-panel button to view the differential signal.

5.	Select Measurement> Wizard, to run the Serial Data Wizard.

6.	Make Wizard Selections as shown in the yellow text in the following figure.

7.	Proceed to Run the Analysis and View the Results.


Use TCA-SMA Adapters on CH1 and CH3 as Single-Ended Sources for Analysis

1.	Use a 1 Meter SMA cable and TCA-SMA adapter to connect between "D+" on the training board and CH1 on the oscilloscope.

2.	Use another 1 Meter SMA cable and TCA-SMA adapter to connect between "D-" on the training board and CH3 on the oscilloscope.

3.	Push the CH3 vertical channel button to display Ch3.

4.	Push the AUTOSET front-panel button to view both signals.

5.	Adjust both Ch1 and Ch3 to 200 mV/div to get a better view of the waveforms.

6.	Select Measurement> Wizard to run the Serial Data Wizard.

7.	Make Wizard Selections as shown in the yellow text in the following figure.

8.	Proceed to Run the Analysis and View the Results.


Run the Analysis and View Results
Run the Analysis and View the Results

1.	Run the Analysis by clicking [image] in the Wizard.

2.	The result of the analysis is displayed as shown in the following figure.

Statistics of measurement results are shown in the lower half of the oscilloscope display. The RT-Eye diagram and Mask are shown in the upper half of the oscilloscope display. You can change the Time units from UIs to seconds depending on what the standard calls for. The magenta dots in the Eye diagram represent the recovered clock. The Eye diagram shows statistical representation of the Eye diagram in an accumulated waveform database display. Multiple jitter plots (the TIE Jitter Histogram, Spectrum, and Bathtub curve) are also displayed. Click the Details button to view the details of each measurement.

3.	Proceed to MJSQ Jitter Analysis.


MJSQ Jitter Analysis

This section describes how to perform jitter analysis compliant with the T11.2 MJSQ methodology using the Spectrum Approach to Jitter Analysis. In the previous section, the default method (Arbitrary Pattern) was used as the Jitter method. To perform analysis consistent with T11.2 MJSQ "spectrum approach", a repeating pattern is used. The signal being used in this lab is a 127 bit PRBS repeating pattern. To change to the repeating pattern method, follow these steps:

1.	Select Measurements> Configure> Jitter

2.	Select Type> Repeating

3.	Select Pattern> Custom

4.	Input 127 UI into the Pattern Length Control.

5.	Click Clear Results.

6.	Click Start to perform the Analysis.

7.	Select Jitter @ BER from the Results Details: Select Measurement pull-down.

The three views of Jitter and the measurements provide a good way to see how Jitter measurements are made with the Spectrum Method of Rj/Dj separation. The TIE Histogram (lower left plot) is the traditional way of measuring jitter on an oscilloscope. This method is limited by the amount of statistical certainty that can be achieved in a reasonable amount of time. Thus, more advanced DSP methods are used to determine the Jitter Eye Opening, Total Jitter, Random Jitter, and Deterministic Jitter.

The TIE measurements are transformed into the frequency domain by performing an FFT on the raw TIE data, thus creating the jitter spectrum shown in the upper right plot. The spikes in the frequency domain represent Deterministic jitter. Further analysis can be done to determine which spikes are Duty Cycle Distortion (DCD) or Data Dependent (DDJ-also known as ISI), and which are Periodic (PJ). Once these values are removed (DJ), then what is left is a noise floor which represents the Random Jitter (RJ). These values are used to create the Cumulative Distribution Function (CDF), commonly known as the Bathtub Curve, shown in the lower right hand plot. The magenta line at 10-12 BER represents the Jitter Eye Opening measurement. The following equation can be solved using the measurement results:

Jitter Eye Opening + Total Jitter = 1UI

8.	Proceed to Using MyTest.


Using MyTest

MyTest allows you to save your favorite test and run it automatically when you start the application. For example, now that you have performed the MJSQ jitter test, you can use the following procedure to save and run the MJSQ jitter test as MyTest.

1.	Select Measurements> Save MyTest

2.	Select File> Exit

3.	Select No when the dialog asks if you want to save oscilloscope settings.

4.	Push the DEFAULT SETUP front-panel button to start from a known setup.

5.	From the Oscilloscope application menu, select File> Run Application> RT-Eye Serial Compliance and Analysis on non-B models, or Applications> RT-Eye Serial Compliance and Analysis on B or C models.

6.	After you launch the RT-Eye application, select Run Mytest from the welcome dialog box. In this example, the MJSQ test is run automatically.

The RT-Eye MyTest feature allows you to run your favorite test with a single click.


Defining a Limits Module

This section demonstrates how to apply a limit to a measurement and create a custom Pass/Fail condition on the TIE jitter measurement described in the previous section.

1.	Select the Measurement> Limits menu.

2.	Select New under Measurement Limits Editor.

3.	Select TIE Jitter as the Measurement.

4.	Select Min as Statistic and Enter –60ps for limit.

5.	Select the + button to add a measurement limit.

6.	Select TIE Jitter as the Measurement.

7.	Select Max as Statistic and Enter +60ps for limit.

8.	Click the Save As button.

9.	Save file as Jitter.lim.

10.	Close Limits Editor.

11.	Select Limits> Browse.

12.	Select Jitter as the Limits File.

13.	Click Open.

14.	Select Limits> On.

15.	Return to Results> Details menu.

16.	Click the Clear Results button.

17.	Click the Start button.

18.	The defined Pass/Fail status appears in the Status column of the Results panel. Proceed to Creating a Compliance Report.


Creating a Compliance Report

This section demonstrates how to create a compliance report based on the previous analysis.

1.	Select Utilities> Reports.

2.	Click Generate. The resulting report can be exported to an RTF file format and read by other applications such as Microsoft Word. The report can also be printed to a PDF file if a PDF distiller is installed on the instrument.

3.	Proceed to PCI Express Compliance Test.


PCI Express Compliance Tests

This section demonstrates how to perform a PCI Express Compliance Test. The PCI Express module must be present to complete this part of the lab. If your instrument does not have a PCI Express Compliance Module installed, proceed to Serial Analysis Lab Conclusion.

1.	Select Modules> PCI Express from the RT-Eye menu.

2.	Click the Select Required button.

3.	Select Test Point> Driver.

4.	Select the correct Probe Type (Single Ended or Differential) depending on your probe configuration.

5.	Click the Autoset button.

6.	Click the Start Button.

Results of PCI Express Add in Card Compliance Test

In this example, the signal under test fails the PCI Express compliance test. This is because the PCI Express specification calls for 3-4dB of De-emphasis on the nontransition bits (or pre-emphasis on transition bits). Since the signal does not have the proper level of de-emphasis, it fails the transition bit mask. The number of mask hits shows up in the compliance results as a mask failure.

7.	Click the Clear Results button.

8.	Return to the Measurement> Select menu.

9.	Select Receiver as the Test Point.

10.	Click the Select Required button.

11.	Click the Start button.

Results of PCI Express Eye Transmitter Compliance Test

In the PCI Express Receiver test, there is a single Receiver Mask. This test is performed by probing a device close to the receiver pins of a SerDes. This signal passes the receiver compliance test.

12.	Proceed to Serial Analysis Lab Conclusion.


Serial Analysis Lab Conclusion

Congratulations! You have completed the RT-Eye Serial Analysis Lab. We hope that this has been helpful in understanding the capabilities of the RT-Eye software solution and will help you in the validation and compliance testing of your devices.


Docking the Application

To Dock the RT-Eye application, select File> Dock in the application menu bar. This positions the application at the default location.


Undocking the Application

To Undock the RT-Eye application, select File> Undock in the application menu bar. After you undock the application, you can click and drag the application tool bar to position the application anywhere on the screen.


General Config

The General Config control allows you to set rise, fall, and amplitude measurements either for transition bits or all bits. The transition bits refer to edge transitions for which the preceding transition was only one unit interval away. This may be important for signals with pre-emphasis, since the transition following a string of two or more like bits has an intentionally low swing that you may not want to measure.

You can also set the option to save maximum and minimum values of the worst case waveforms obtained during scan mode to files in the waveforms directory.


My Test
About My Test

The MyTest feature allows you to save a single measurement configuration so that it can be recalled and run at any time with a single click. This is similar to the save/recall feature (which allows as many named configurations as you want), except that MyTest is designed to be easily accessible and runs automatically when selected.

See also:

Saving MyTest

Running MyTest