Tektronix TDSDDM2 User manual

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User Manual

TDSDDM2 Disk Drive Measurements Application

071-0815-01

This document supports software version 1.0.0 and above.

www.tektronix.com

Copyright © Tektronix, Inc. 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.

Use, duplication, or disclosure by the Government is subject to restrictions as set forth in subparagraph (c)(1)(ii) of the Rights in Technical Data and Computer Software clause at DFARS 252.227-7013, or subparagraphs (c)(1) and (2) of the Commercial Computer Software -- Restricted Rights clause at FAR 52.227-19, as applicable.

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, Inc., P.O. Box 500, Beaverton, OR 97077

TEKTRONIX and TEK are registered trademarks of Tektronix, Inc.

WARRANTY

Tektronix warrants that the media on which this software product is furnished and the encoding of the programs on the media will be free from defects in materials and workmanship for a period of three (3) months from the date of shipment. If a medium or encoding proves defective during the warranty period, Tektronix will provide a replacement in exchange for the defective medium. Except as to the media on which this software product is furnished, this software product is provided “as is” without warranty of any kind, either express or implied. Tektronix does not warrant that the functions contained in this software product will meet Customer’s requirements or that the operation of the programs will be uninterrupted or error-free.

In order to obtain service under this warranty, Customer must notify Tektronix of the defect before the expiration of the warranty period. If Tektronix is unable to provide a replacement that is free from defects in materials and workmanship within a reasonable time thereafter, Customer may terminate the license for this software product and return this software product and any associated materials for credit or refund.

THIS WARRANTY IS GIVEN BY TEKTRONIX IN LIEU OF ANY OTHER WARRANTIES, EXPRESS OR IMPLIED. TEKTRONIX AND ITS VENDORS DISCLAIM ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. TEKTRONIX’ RESPONSIBILITY TO REPLACE DEFECTIVE MEDIA OR REFUND CUSTOMER’S PAYMENT IS THE SOLE AND EXCLUSIVE REMEDY PROVIDED TO THE CUSTOMER FOR BREACH OF THIS WARRANTY. TEKTRONIX AND ITS VENDORS WILL NOT BE LIABLE FOR ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES IRRESPECTIVE OF WHETHER TEKTRONIX OR THE VENDOR HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES.

Getting Started

General Safety Summary ix.........................................

Preface xi........................................................

Related Documentation and Online Help xi..............................

Conventions xii....................................................

Contacting Tektronix xii..............................................

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

Compatibility 1--1...................................................

Requirements and Restrictions 1--2......................................

Updates Through the Web Site 1--2......................................

Accessories 1--3.....................................................

Installation 1--5...............................................

Applying a New Label 1--5............................................

Installing the Application 1--6..........................................

From the Compact Disc 1--7........................................

From Floppy Disks 1--7...........................................

Enabling the Application 1--8..........................................

Connecting to a System Under Test 1--8..................................

Primary Setup 1--9...............................................

Secondary Setup 1--10.............................................

Configuration 1--11.............................................

Setting Up the Oscilloscope Trigger 1--11..................................

Setting Up the Application Trigger 1--12...................................

Hysteresis 1--14......................................................

Configuring the Input Waveforms 1--16...................................

Operating Basics

Basic Operations 2--1..........................................

Application Interface 2--1.............................................

Using Basic Oscilloscope Functions 2--2..................................

Using Online Help 2--2............................................

Minimizing and Maximizing the Application 2--2.......................

Returning to the Application 2--3....................................

Application Directories and File Names 2--3...........................

Setting Up the Application 2--4.........................................

Selecting a Measurement 2--4.......................................

Configuring a Measurement 2--9....................................

Taking Measurements 2--15.............................................

Taking New Measurements 2--15.....................................

Localizing Measurements 2--16......................................

Analyzing the Results 2--16.............................................

Viewing Statistics 2--18.............................................

Viewing Plots 2--18................................................

Clearing Results 2--19..............................................

Saving the Results to a File 2--19.........................................

Logging Statistics 2--19............................................

TDSDDM2 Disk Drive Measurements Application User Manual

Table of Contents

Data Log File Format 2--20..........................................

Viewing a Data Log File 2--21...........................................

Saving and Recalling Setups 2--21........................................

Saving a Setup 2--22...............................................

Recalling a Saved Setup 2--23........................................

Recalling the Default Setup 2--24.....................................

Exiting the Application 2--24............................................

Tutorial 2--25..................................................

Setting Up the Oscilloscope 2--25........................................

Starting the Application 2--25...........................................

Recalling a Waveform File 2--26.........................................

Taking a TAA Measurement 2--27........................................

Saving the Results to a Data Log File 2--29.................................

Viewing a Data Log File 2--29...........................................

Stopping the Tutorial 2--31.............................................

Returning to the Tutorial 2--31...........................................

Application Examples 2--33......................................

Configuring a Measurement 2--34........................................

Specifying a Range of Sectors 2--34...................................

Specifying a Limit Test 2--34........................................

Specifying Gating 2--34............................................

Specifying Hysteresis 2--35..........................................

Specifying a Filter 2--35............................................

Using Reference Waveforms 2--35........................................

Measuring TAA 2--35..................................................

Measuring PW50 2--36................................................

Measuring Asperity 2--37...............................................

Measuring Overwrite 2--38.............................................

Measuring Resolution 2--40.............................................

Measuring Baseline Shift 2--40..........................................

Measuring NLTS 2--41.................................................

Measuring SNR 2--43..................................................

Creating and Viewing Track Profile Plots 2--45..............................

GPIB Program Example 2--49....................................

Guidelines 2--49......................................................

Program Example 2--49................................................

Reference

Menu Structure 3--1...........................................

Parameters 3--3...............................................

Measurements Menu 3--3..............................................

TAA/PW50 Menu 3--3............................................

NLTS/Other Menu 3--4............................................

Save/Recall Menu 3--6............................................

Minimize Menu 3--6..............................................

Inputs Menu 3--6....................................................

Inputs/Trigger Menu 3--6..........................................

Inputs Filters Menu 3--7...........................................

Inputs General Menu 3--7..........................................

View Menu 3--8.....................................................

TDSDDM2 Disk Drive Measurements Application User Manual

Appendices

Table of Contents

Plot Track Profile Menu 3--8...........................................

Log Statistics Menu 3--8..............................................

Help Menu 3--8.....................................................

Sequence Control Menu 3--9...........................................

Appendix A: Measurement Algorithms A--1........................

Oscilloscope Setup Guidelines A--1......................................

TAA Measurements A--1..............................................

TAA+ and TAA-- Measurements A--3.................................

PW50 Measurements A--3.............................................

PW50+ and PW50-- Measurements A--5..............................

NLTS Measurements A--6..............................................

NLTS Initial Measurement A--7......................................

NLTS 1st Adjacent Measurement A--7................................

NLTS 2nd Adjacent Measurement A--8................................

Other Measurements A--9..............................................

SNR Measurement A--9............................................

Asperity Measurement A--9.........................................

Overwrite Measurement A--10........................................

Resolution Measurement A--10.......................................

Baseline Shift Measurement A--11....................................

Snapshot Measurements A--12...........................................

Amplitude Asymmetry (Amplitude asym) A--13.........................

Timing Asymmetry

(Time asym) A--13..........................................

Time Peak-to-Trough (Time PT) and

Time Trough-to-Peak (Time TP) A--14..........................

Calculating Statistics A--14..............................................

Maximum Value A--14..............................................

Minimum Value A--14..............................................

Mean Value A--15.................................................

Standard Deviation Value A--15......................................

Appendix B: Track Profile Plots B--1..............................

Using Track Profiles B--1..............................................

About the Track Profile Reference Memory B--1............................

Appendix C: GPIB Command Syntax C--1.........................

Starting the Application C--2...........................................

VARIABLE:VALUE TDS COMMAND C--2..............................

Index

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Table of Contents

List of Figures

Figure 1--1: TDSDDM2 Disk Drive Measurements Application 1--1....

Figure 1--2: TDS7000 series oscilloscope label location 1--6...........

Figure 1--3: TDS5000 series oscilloscope label location 1--6...........

Figure 1--4: Primary setup connections 1--9........................

Figure 1--5: Secondary setup connections 1--10......................

Figure 1--6: Spectral Control T tab for a TDS7104 oscilloscope 1--11....

Figure 1--7: Sector Trigger Mode default values 1--13................

Figure 1--8: One track 1--14......................................

Figure 1--9: Using hysteresis to avoid false identification of peaks 1--15..

Figure 1--10: Hysteresis option 1--15...............................

Figure 2--1: Application interface 2--1.............................

Figure 2--2: Returning to the application 2--3......................

Figure 2--3: TAA/PW50 Measurements menu 2--4...................

Figure 2--4: How to enter Limit Test option values 2--5..............

Figure 2--5: NLTS/Other Measurements menu 2--6..................

Figure 2--6: NLTS Parameter options 2--7.........................

Figure 2--7: How the application calculates the polynominal index 2--8.

Figure 2--8: SNR Parameter options 2--8..........................

Figure 2--9: Asperity Parameter options 2--9.......................

Figure 2--10: Inputs/Trigger menu 2--9............................

Figure 2--11: Inputs Filters menu 2--11.............................

Figure 2--12: Filter characteristics 2--12............................

Figure 2--13: Using both Highpass and Lowpass filters 2--12...........

Figure 2--14: Inputs General menu 2--14...........................

Figure 2--15: Sequence Control menu 2--15.........................

Figure 2--16: Results as statistics and as a Track Profile plot 2--17......

Figure 2--17: Example of viewing data in a .csv file 2--17..............

Figure 2--18: Plot Track Profile menu 2--18.........................

Figure 2--19: Log Statistics menu 2--19.............................

Figure 2--20: Log file directory 2--20...............................

Figure 2--21: Save/Recall Measurements menu 2--21.................

Figure 2--22: Save directory 2--22.................................

Figure 2--23: Recall directory 2--23................................

Figure 2--24: Exit menu 2--24.....................................

TDSDDM2 Disk Drive Measurements Application User Manual

Table of Contents

Figure 2--25: Starting the application 2--26.........................

Figure 2--26: Oscilloscope reference waveform setup 2--26............

Figure 2--27: Waveform directory to recall reference waveforms 2--27...

Figure 2--28: Inputs/Trigger menu setup 2--27.......................

Figure 2--29: Taking a measurement 2--28..........................

Figure 2--30: TAA lesson: statistical results 2--28....................

Figure 2--31: Log Statistics menu with default file name 2--29..........

Figure 2--32: Log file with default file name 2--30....................

Figure 2--33: TAA.csv file viewed in Wordpad 2--30..................

Figure 2--34: PW50 measurement results example 2--36...............

Figure 2--35: Asperity measurement results example 2--37.............

Figure 2--36: Overwrite measurement, PASS 1 example 2--39..........

Figure 2--37: Overwrite measurement results, PASS 2 example 2--39....

Figure 2--38: Baseline Shift measurement results example 2--41........

Figure 2--39: NLTS measurement results example 2--43..............

Figure 2--40: SNR measurement results example 2--45................

Figure 2--41: Track Profile plot example 2--46......................

Figure 2--42: Track Profile plot with cursors 2--47...................

TDSDDM2 Disk Drive Measurements Application User Manual

Table of Contents

List of Tables

Table 1--1: Compatible oscilloscopes 1--1..........................

Table 1--2: Primary setup channel assignments 1--9.................

Table 1--3: Default channel assignments 1--16.......................

Table 2--1: Application interface items 2--2........................

Table 2--2: Default directory names 2--3..........................

Table 2--3: File name extensions 2--3.............................

Table 2--4: TAA/PW50 measurements options 2--4..................

Table 2--5: Limit Test options 2--5...............................

Table 2--6: Limit Test entry methods 2--5.........................

Table 2--7: NLTS/Other Measurements options 2--6.................

Table 2--8: NLTS Parameter options 2--7..........................

Table 2--9: SNR Parameter options 2--8...........................

Table 2--10: Trigger options 2--10.................................

Table 2--11: Filters options 2--11..................................

Table 2--12: General options 2--14................................

Table 2--13: Sequence Control menu 2--15..........................

Table 2--14: Plot Track Profile options 2--18........................

Table 2--15: Log Statistics options 2--20...........................

Table 2--16: Save/Recall Measurements options 2--22................

Table 2--17: Waveform files and application examples 2--33...........

Table 3--1: TAA/PW50 Limit Test area parameters 3--4.............

Table 3--2: NLTS/Other Limit Test area parameters 3--4............

Table 3--3: NLTS Parameters area 3--5...........................

Table 3--4: SNR Parameters area 3--5............................

Table 3--5: Asperity Parameter area 3--6..........................

Table 3--6: Save/Recall Measurements menu parameters 3--6.........

Table 3--7: Input Channels area parameters 3--6...................

Table 3--8: Trigger area parameters 3--7..........................

Table 3--9: Filter 1 and Filter 2 areas parameters 3--7...............

Table 3--10: General menu parameters 3--7........................

Table 3--11: Plot Track Profile menu parameters 3--8...............

Table 3--12: Log Statistics menu parameters 3--8...................

Table 3--13: Sequence Control menu parameters 3--9...............

TDSDDM2 Disk Drive Measurements Application User Manual

Table of Contents

Table C--1: VARIABLE:VALUE TDS COMMAND arguments

and queries C--2...........................................

Table C--2: Measurement results queries C--5......................

Table C--3: Results returned by measurements C--7.................

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Table of Contents

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TDSDDM2 Disk Drive Measurements Application User Manual

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.

Ground the Product. This product is grounded through the grounding conductor of the power cord. To avoid electric shock, the grounding conductor must be connected to earth ground. Before making connections to the input or output terminals of the product, ensure that the product is properly grounded.

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.

Connect the ground lead of the probe to earth ground only.

Do not apply a potential to any terminal, including the common terminal, that exceeds the maximum rating of that terminal.

Use Proper Fuse. Use only the fuse type and rating specified for this product.

Avoid Exposed Circuitry. Do not touch exposed connections and components

when power is present.

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

Do Not Operate in Wet/Damp Conditions.

Do Not Operate in an Explosive Atmosphere.

Keep Product Surfaces Clean and Dry.

Provide Proper Ventilation. Refer to the manual’s installation instructions for

details on installing the product so it has proper ventilation.

TDSDDM2 Disk Drive Measurements Application User Manual

General Safety Summary

Symbols and Terms

Terms in this Manual. These terms may appear in this manual:

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. These 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 on the product:

CAUTION Refer to Manual WARNING

High Voltage

Protective Ground

(Earth) Terminal

TDSDDM2 Disk Drive Measurements Application User Manual

Preface

This manual contains operating information for the TDSDDM2 Disk Drive Measurements Application. The manual consists of the following chapters:

H The Getting Started chapter briefly describes the TDSDDM2 Disk Drive

Measurements Application, lists oscilloscope compatibility, and provides installation instructions.

H The Operating Basics chapter covers basic operating principles of the

application and includes a tutorial that teaches you how to set up the application to acquire a waveform, take measurements, and view the results.

The Application Examples section includes examples of tests and measurements to give you ideas on how to solve your own measurement problems.

To show you how to operate the application using GPIB commands, this chapter also contains a simple GPIB program.

H The Reference chapter includes a diagram of the menu structure and

descriptions of parameters.

H The Measurement Algorithms appendix contains information on measure-

ment guidelines and on how the application takes the measurements.

H The Track Profile Plots appendix contains information about using track

profile plots.

H The GPIB Command Syntax appendix contains a list of arguments and values

that you can use with the GPIB commands and their associated parameters.

Conventions

You can find a portable document format (PDF) file of the installation manual in the Documents directory on the Optional Applications Software on Windows-

Based Oscilloscopes Installation CD--ROM.

IDEMA Standard. The International Disk Drive Equipment and Materials Association (IDEMA) 1995 Standards Binder, section T for Test Methods, is the

source document for test criteria used by theTDSDDM2 application. Polynomials must be valid according to the 1995 IDEMA “white paper.”

This manual uses the following conventions:

H This manual refers to the TDSDDM2 Disk Drive Measurements Application

as the TDSDDM2 application or as the application.

H This manual refers to any product on which this application will run as an

oscilloscope

H When steps require that you make 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 Measururements>Save/Recall>Recall.

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TDSDDM2 Disk Drive Measurements Application User Manual

Contacting Tektronix

Preface

Phone 1-800-833-9200*

Address Tektronix, Inc.

Department or name (if known) 14200 SW Karl Braun Drive P.O. Box 500 Beaverton, OR 97077 USA

Web site www.tektronix.com

Sales support 1-800-833-9200, select option 1*

Service support 1-800-833-9200, select option 2*

Technical support Email: techsupport@tektronix.com

1-800-833-9200, select option 3* 1-503-627-2400

6:00 a.m. -- 5:00 p.m. Pacific time

* This phone number is toll free in North America. After office hours, please leave a

voice mail message. Outside North America, contact a Tektronix sales office or distributor; see the Tektronix web site for a list of offices.

TDSDDM2 Disk Drive Measurements Application User Manual

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Preface

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TDSDDM2 Disk Drive Measurements Application User Manual

Getting Started

Product Description

The TDSDDM2 Disk Drive Measurements Application is a Java-based application that enhances basic capabilities of some Tektronix oscilloscopes.

The application provides disk drive measurements, can display the results as statistics or as a plot, and can save the results to a data log file.

Figure 1--1 shows an example of statistical results for a TAA measurement in the application part of the display (lower half) and a Track Profile plot of those results in the oscilloscope part of the display (upper half).

Figure 1- 1: TDSDDM2 Disk Drive Measurements Application

Compatibility

The Disk Drive Measurements Application is compatible with several TDS7000 series oscilloscopes. Table 1--1 lists the oscilloscopes and firmware version numbers.

Table 1- 1: Compatible oscilloscopes

Model number* Firmware version

TDS7054 and TDS7104 1.2.0 or above

TDS7404 1.3.0 or above

TDS7254 1.3.1 and above

TDS5054 and TDS5104 1.0.0 or above

* For a current list, see the Software and Drivers category on www.tektronix.com.

TDSDDM2 Disk Drive Measurements Application User Manual

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Product Description

Requirements and Restrictions

The SunT Java Run-time Environment V1.2.2 or above must be installed on the oscilloscope to operate the TDSDDM2 application.

The TDSDDM2 application does not support hard disk drives that mark the beginning of a track by the absence of a sector pulse.

NOTE. This application may be compatible with future models of oscilloscopes that have different specifications. If this occurs, menus or options that are unavailable will appear dim if they are beyond the acquisition capability of the oscilloscope.

Updates Through the Web Site

You can find information about this and other applications at the Tektronix Inc. web site, www.tektronix.com. Check this site for application updates and for other free applications.

To install an application update, you will need to download it from the Tektronix web site to the oscilloscope hard disk.

NOTE. More information about changes to the application or installation is in a

Readme.txt file on the web site. You should read it before you continue.

To download an application from the web site, follow these steps:

1. Access www.tektronix.com/Software & Drivers/Oscilloscopes.

2. Scroll through the files to the application that you want, select the file, and

download it to your hard disk drive. If necessary, unzip the file.

If your oscilloscope is connected to a network, you do not need to follow the

remaining steps.

3. If your oscilloscope is not connected to a network, copy the application from

the hard disk to blank, DOS-formatted floppy disks.

NOTE. To ensure that the files were downloaded successfully, always unzip the files on a hard disk before copying them to floppy disks.

1- 2

4. To install the application, refer to From Floppy Disks procedure on page 1--7.

TDSDDM2 Disk Drive Measurements Application User Manual

Accessories

Product Description

There are no standard accessories for this product other than this manual.

To connect the Read Signal input to an oscilloscope channel, Tektronix Differential Probes are recommended, such as the P6247 or P6248 probe for TDS7054 and TDS7104 oscilloscopes, or the P7330 probe for a TDS7404 oscilloscope.

TDSDDM2 Disk Drive Measurements Application User Manual

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Product Description

1- 4

TDSDDM2 Disk Drive Measurements Application User Manual

Installation

This section contains information on the following tasks:

H Applying a new label

H Installing the TDSDDM2 application

H Enabling the application

H Connecting to a system under test

NOTE.TheOptional Applications Software on Windows-Based Oscilloscopes Installation Manual contains up-to-date information and procedures. Since

installation procedures may be different for the TDS7000 series and other oscilloscopes, be sure to check this manual before you install the software.

You can find a portable document format (PDF) file of the installation manual in the Documents directory on the Optional Applications Software on Windows-

Based Oscilloscopes Installation CD--ROM.

Applying a New Label

If you receive a newer version of this application, or purchase an application that did not exist when you bought your oscilloscope, you need to apply a new label to the rear panel of the oscilloscope. The label contains important information, such as the serial number of the oscilloscope, options purchased for that serial number, and an authorized Option Installation Key number. Each label is unique.

Figure NO TAG shows where to apply the new label on the back of a TDS7000 series oscilloscope.

Figure 1--3 shows where to apply the new label on the back of a TDS5000 series oscilloscope.

TDSDDM2 Disk Drive Measurements Application User Manual

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Installation

Label location

Figure 1- 2: TDS7000 series oscilloscope label location

Label location

Figure 1- 3: TDS5000 series oscilloscope label location

Installing the Application

Normally, the TDSDDM2 application resides on the hard disk drive of your oscilloscope. However, you may still need to install the application software for the following reasons:

H You receive an application introduced after you received your oscilloscope

H Youhavetorebuildtheharddrive

NOTE. To operate the TDSDDM2 application, the Java Run-time Environment (JRE) V1.2.2 or above must be installed on your oscilloscope.

If the JRE is not installed, a message displays when you try to start the application. If the message appears, reinstall the JRE from the optional applications compact disc (CD).

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TDSDDM2 Disk Drive Measurements Application User Manual

Installation

From the Compact Disc

To install the TDSDDM2 application from the optional applications software CD for your instrument, follow these steps:

1. If the keyboard is not installed, connect it to the oscilloscope rear panel (the optional-accessory keyboard plugs into the USB connector).

2. Power on the oscilloscope to start Windows.

3. Install the optional applications software CD in the CD-ROM reader on the

rear-panel of the oscilloscope.

4. Select the My Computer icon.

5. In the Exploring -- My Computer window, select the D: (CD-ROM) drive.

6. The Java Run-time Environment software must be installed before you can

install optional application software. If the Java Run-time Environment software is already installed, skip to step 7; otherwise, follow these steps:

a. Select the Jre directory.

b. Select the .exe file in the Jre directory.

c. Accept all default settings recommended by the install program.

7. Select the Tdsddm2 directory.

From Floppy Disks

8. Select the Setup.exe file to start the install program.

9. Follow the instructions given by the install program. The oscilloscope must

reboot to complete the installation process.

To install the TDSDDM2 application from floppy disk, follow these steps:

1. Power on the oscilloscope to start Windows.

2. Insert disk #1 in the floppy disk drive.

3. Select the My Computer icon.

4. In the Exploring -- My Computer window, select the A: (3 1/2 Floppy) drive.

NOTE. Additional information about the application or installation is located in a Readme.txt file on the floppy disk. Read the file before you continue.

If you are updating the application, the Readme.txt file on the Tektronix w eb site supercedes the Readme.txt file on the floppy disk.

5. Select the Setup.exe file to start the install program.

6. Follow the on-screen instructions.

TDSDDM2 Disk Drive Measurements Application User Manual

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Installation

7. When the installation is complete, the oscilloscope will restart. You need to

Enabling the Application

You will need to enter the authorized Option Installation Key to enable the application. The key is specific to the serialized oscilloscope and options for which it was purchased.

NOTE. Do not enter this key until all application software that you have purchased has been installed.

To enter the key number, follow these steps:

Wait until after the floppy disk drive LED has gone out to remove each floppy disk and insert another.

remove the final floppy disk when prompted.

1. If the oscilloscope powered on in the toolbar mode (default), select the Menu button (upper right corner of the display) to put the oscilloscope into menu-bar mode. In menu-bar mode you should see a PC-style menu across the top of the display.

2. Go to the Utility menu in the menu bar and select Option Installation.

3. Follow the on-screen instructions to enter the alphanumeric key number

exactly as it is printed on the rear-panel label. Figure NO TAG on page NO TAGNO TAG shows the location of the label on the back of the oscilloscope.

Connecting to a System Under Test

For best signal accuracy, you should use one differential probe and two standard probes. For connection to the Read signal, use a differential probe, such as the Tektronix P6247 or P6248 probe for TDS7054 and TDS7104 oscilloscopes, or the P7330 probe for a TDS7404 oscilloscope. For connection to the Index and Sector signals, use standard oscilloscope probes, such as the P6139A passive probe or P6243 active probe for TDS7054 and TDS7104 oscilloscopes, or the P7240 active probe for a TDS7404 oscilloscope.

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TDSDDM2 Disk Drive Measurements Application User Manual

Installation

Table 1--2 shows the default channel-to-signal assignments. You can change the channel assignments to match your configuration.

Table 1- 2: Primary setup channel assignments

Channel Description

Ch 1 Read signal from the disk drive preamp channel

Ch 2 Read Gate signal (optional)

Ch 3 Sector pulse, marking the beginning of the sector on the track

Ch 4 Index pulse, marking the beginning of the track

NOTE. The TDSDDM2 application does not support disk drives that mark the beginning of a track by the absence of a sector pulse. For this case, a timeout trigger setup is needed to identify the beginning of the track.

There are two connection configurations, primary and secondary.

Primary Setup

WARNING. To avoid electric shock, you must ensure that power is removed from the SUT before attaching a probe to it. Do not touch exposed conductors except with the properly rated probe tips. Refer to the probe manual for proper use.

Power down the SUT before connecting probes to it.

Use the primary setup if you want the oscilloscope to control the disk measurements. The primary setup is used for most configurations. Connect the disk drive to the oscilloscope as shown in Figure 1--4.

Test oscilloscope

Disk drive

CH 1 CH 4

CH 3

Index signal (standard probe)

Sector signal (standard probe)

Read signal (differential probe)

Figure 1- 4: Primary setup connections

TDSDDM2 Disk Drive Measurements Application User Manual

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Installation

Secondary Setup

When using the secondary setup, you must specifically program the test measurement control sequences. Refer to the GPIB Program Example section andtothe GPIB Command Syntax appendix in this manual for more information on how to control the application with a GPIB program.

Connect the disk drive to the oscilloscope as shown in Figure 1--5.

Test oscilloscope

Disk drive

CH 1 CH 2

Read Gate signal (standard probe)

Read signal (differential probe)

Figure 1- 5: Secondary setup connections

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TDSDDM2 Disk Drive Measurements Application User Manual

Configuration

This section describes configuration tasks that you should perform before you start taking measurements. For the most part, these tasks configure the oscilloscope and Disk Drive Measurements Application to correctly acquire the signals from the disk drive under test. You can find more information on setup parameters for specific measurements in the Parameters sectiononpage3--3.

Setting Up the Oscilloscope Trigger

If you use the Read Gate, User, or Index Trigger mode in the application, you must manually set up the oscilloscope trigger. To do so, follow these steps:

1. Connect the Index, Sector, and Read signals to Ch 4, Ch 3, and Ch 1 respectively.

2. Go to Math in the oscilloscope menu bar and select Spectral Controls> T tab. Figure 1--6 shows the T tab.

Figure 1- 6: Spectral Control T tab for a TDS7104 oscilloscope

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Configuration

3. Use the Multipurpose (MP) knobs to set the Sample Rate to 500 MS/s,

1.25 GS/s, 2.5 GS/s, 5 GS/s, or 10 GS/s.

4. Use the MP knobs to set the Record Length to 50,000, 100,000, 200,000 or 400,000.

For NLTS measurements, set the Record Length to at least 200,000.

5. Set up the trigger:

a. Go to Trig in the menu bar, access the A Event (Main) Trigger Setup

menu, select the A Event tab, and set the Coupling to DC.

b. Set the Slope to the appropriate edge for your disk drive signals, rising

or falling.

c. Set the Level to an appropriate level for your disk drive signals, or select

Set 50%.

d. Select the Mode tab, and set the Trigger Mode to Normal.

e. Set the Holdoff to Auto.

Setting Up the Application Trigger

Before you begin to take measurements, you should specify the following trigger parameters:

H Trigger mode, which selects the input trigger signal

H Start Sector and Stop Sector (used with the Sector Trigger mode only),

which specifies the range of sectors to be measured

H Preamble (used with the Sector Trigger mode only), which the application

uses to avoid acquiring the preamble

Set up the trigger parameters as follows:

1. Start the application. Go to the File menu in the oscilloscope menu bar and select Run Application> Disk Drive Measurements 2.

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Configuration

2. Select Inputs> Input/Trigger and select one of the following Trigger Modes:

Sector Select Sector mode if you want to perform a measurement

over a range of sectors rather than over the entire track. The application sets up the following oscilloscope trigger controls:

A Event trigger -- the Source is the Index Pulse

B Event trigger -- the Source is the Sector Pulse

A --> B Seq trigger (delayed trigger) -- the Trig Event is the Start Sector number, Horiz Delay is On, and the Trig on nth event is the Preamble duration

Read Gate Select Read Gate mode if you want to trigger on the Read

Gate signal. The A --> B Seq is not used with this selection.

User Select User mode if you want to use your own custom trigger

setup. When you select User, the application does not set up the oscilloscope trigger controls.

User is the default Trigger Mode selection.

Index Select Index mode if you want to trigger on the Index Pulse

signal. The A --> B Seq is not used with this selection.

NOTE. If you select the Read Gate, User, or Index Trigger mode, you must manually set up the oscilloscope trigger as described on page 1--11.

3. For the Sector Trigger Mode, use the MP knob (or keypad) to select values for the Start Sector and Stop Sector options. Figure 1--7 shows the default values.

Figure 1- 7: Sector Trigger Mode default values

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Multipurpose knob icon

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Configuration

NOTE. The A --> B Seq trigger has a minimum count setting of 1. If you want to trigger on sector 0, you must enter the value of N, where N is the total number of sectors on the track. The first Sector Pulse after the Index Pulse is sector 1.

Figure 1--8 shows how the sectors are numbered with respect to the B Event trigger in the oscilloscope application.

Hysteresis

Sector 3 data

Sector 0 data

Sector 0 preamble

Index pulse

Sector N-- 1

Figure 1- 8: One track

4. For the Sector Trigger Mode, set the Preamble option. Use the MP knob (or keypad) to select a value that is greater than the actual signal preamble duration. This ensures that the application does not acquire the preamble and excludes it from the measurement.

Many of the measurements search for a local event called a peak and trough pair. You can set the hysteresis level so that noise will not cause false identification of peaks in the Read waveform. For a peak or trough to be found, the signal must be greater than the hysteresis level.

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The application uses the value of the Hysteresis option in many measurements, such as TAA, PW50, Asymmetry (for TAA Snapshot and PW50 Snapshot measurements), Overwrite, Resolution, and Baseline Shift.

Figure 1--9 shows how to use the hysteresis to avoid false identification of peaks and troughs.

TDSDDM2 Disk Drive Measurements Application User Manual

Peak

Signal

Hysteresis

setting

Noise

Trough

Figure 1- 9: Using hysteresis to avoid false identification of peaks

Configuration

To set the hysteresis levels, follow these steps:

1. Select Inputs> General.

2. Use the multipurpose knob (or keypad) to select a value in the Hysteresis

option.

The units for hysteresis are in divisions. The application uses the value for both the positive hysteresis level and the negative hysteresis level. For example, if you select a value of 2 divisions, the hysteresis levels are set to +2 divisions and

--2 divisions above and below the waveform baseline.

Figure 1- 10: Hysteresis option

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Configuration

Configuring the Input Waveforms

Your configuration may not match the TDSDDM2 waveform assignments. Table 1--3 lists the default channel assignments.

Table 1- 3: Default channel assignments

Description Channel

Read signal from the preamp channel Ch 1

Read Gate signal (optional)* Ch 2

Sector Pulse, marking the beginning of the sector on the track** Ch 3

Index Pulse, marking the beginning of the track** Ch 4

* Uses this signal when you select the Read Gate Trigger Mode.

** Uses these signals when you select the Sector Trigger Mode.

NOTE. Oscilloscope channels (Ch1, Ch2, Ch3, and Ch4) connect to real, live signals (waveforms) as opposed to waveforms that have been saved as .wfm files and can be recalled into reference memory (Ref1, Ref2, Ref3, and Ref4).

If necessary, you can reconfigure the input waveforms to match your disk drive configuration. To do so, follow these steps:

1. Go to the Inputs menu in the menu bar and select Input/Trigger. Figure 1--7 on page 1--13 shows the Inputs/Trigger menu.

2. Use the list box for each signal and select the waveform that matches your configuration.

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Operating Basics

Basic Operations

This section contains information on the following topics and tasks:

H Application interface

H Using basic oscilloscope functions

H Setting up the application

H Taking measurements

H Warning messages

H Analyzing the results

H Saving the results to a file

H Viewing a data log file

H Saving and recalling setups

H Exiting the application

Application Interface

Menu bar

Option

Area

The application uses a Windows type of interface. Figure 2--1 shows the Menu bar and some of the buttons and boxes that you use to operate the application.

List box

Command button

Figure 2- 1: Application interface

NOTE. The oscilloscope application shrinks to half size and appears in the top half of the display when the application is running.

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Table 2--1 lists the interface items with a brief description of each.

Table 2- 1: Application interface items

Item Description

Menu bar Located at the top of the application display and contains application menus

Area Visual frame that encloses a set of related options

Option button Button that defines a particular command or task

List box Box that contains a list of items from which you can select one item

Box Box that you can use to type in text, or to enter a value with the Keypad or a

Multipurpose knob

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

used for moving around in that area

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

Command button Button that initiates an immediate action

NOTE. For a quick overview of the complete menu structure, refer to Figure 3--1 and Figure 3--2 starting on page 3--1.

Using Basic Oscilloscope Functions

You can use the Help menu to access information about the application. You can also use other oscilloscope functions and easily return to the application.

Using Online Help

Minimizing and Maximizing the

Application

The application includes Online Help about the application menus and controls.

To display the Online Help, follow these steps:

1. Choose the Help menu from the TDSDDM2 menu bar.

2. Use the Contents, TOC, or Index tabs to navigate through the help.

The application remains displayed when you minimize the oscilloscope. To minimize the application, select Measurements> Minimize.

To maximize the application, select TDSDDM2 in the Windows toolbar.

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Returningtothe

Application

Application Directories

and File Names

When you access oscilloscope functions, the oscilloscope fills the display. You can access oscilloscope functions in the following ways:

H Select the Close button in the application display

H Choose the Menu-bar or Toolbar mode on the oscilloscope and access menus

H Press front-panel buttons

To return to the application, choose the App button. Figure 2--2 shows the App button.

To return to the application, choose the App button

Figure 2- 2: Returning to the application

The application uses directories to save and recall setup files and also uses extensions appended to file names to identify the file type.

Default Directories. Table 2--2 lists default directory names.

Table 2- 2: Default directory names

Directory name Used for

C:\TekApplications\tdsddm2 Home location

C:\TekApplications\tdsddm2\data Data log files

C:\TekApplications\tdsddm2\setups Setup files

C:\TekApplications\tdsddm2\waveforms Waveform files

File Name Extensions. Table 2--3 lists file name extensions used or generated by the application.

Table 2- 3: File name extensions

Extension Typ e

.csv Log file that uses a “comma separated variable” format

.ini Application setup file

.set Oscilloscope setup file saved and recalled with an .ini file; both files will

have the same name

.wfm Waveform file that can be recalled into a reference memory

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Setting Up the Application

You can set up the application to take disk drive measurements from the SUT, you can plot the results, and you can save the statistical results to a data log file.

Selecting a Measurement

There are four Measurements menu items. Two allow you to select and configure a measurement, one allows you to save and recall measurement setups, and one allows you to minimize the application.

TAA/PW50 Measurements Menu. To access the TAA/PW50 Measurements menu, go to the Measurements menu in the menu bar and choose TAA/PW50. Figure 2--3 shows the TAA/PW50 Measurements menu.

Figure 2- 3: TAA/PW50 Measurements menu

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Table 2--4 lists the TAA/PW50 measurements with a brief description of each.

Table 2- 4: TAA/PW50 measurement options

Option Description

TAA Track Average Amplitude: average peak-to-peak value of data from the

Read signal input

TAA+ Average positive peak value

TAA -- Average negative peak value

TAA Snapshot Provides a summary of TAA measurements

PW50 Pulse Width at 50% of the Peak Amplitude: average pulse width at 50% of

the peak, that includes both peaks and troughs; can also measure around a complete track if specified in the oscilloscope trigger setup

PW50+ Includes only the positive peaks

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Table 2- 4: TAA/PW50 measurement options (Cont.)

Option Description

PW50- Includes only the troughs

PW50 Snapshot Provides a summary of PW50 measurements

LimitTestArea.Table 2--5 lists options in the Limit Test area with a brief description of each. For some measurements, such as TAA, PW50, Overwrite, Resolution, and Baseline Shift, these are the only options.

Table 2- 5: Limit Test options

Option Description

On/Off Enables the application to display PASS or FAIL results based on the limits

Upper Limit Maximum limit allowed for the measurement mean value

Lower Limit Minimum limit allowed for the measurement mean value

Figure 2--4 shows the methods you can use to enter Limit Test values.

Keypad

Multipurpose knob icon

Keypad icon

Minimum value button

Maximum value button

Figure 2- 4: How to enter Limit Test option values

Table 2--6 lists methods that you can use to enter values for Limit Test options.

Table 2- 6: Limit Test entry methods

Entry method Description

Keypad Icon appears when you select the box; select and use to enter a value

Multipurpose knob When you select the multipurpose (MP) knob, a line appears between

the knob and the box; turn the knob on the oscilloscope to select a value

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NLTS/Other Measurements Menu. To access the NL TS/Other Measurements menu, go to the Measurements menu in the menu bar and choose NLTS/Other.

Figure 2--5 shows the NLTS/Other Measurements menu.

Figure 2- 5: NLTS/Other Measurements menu

Table 2--7 lists the NLTS/Other measurement options with a brief description of each.

Table 2- 7: NLTS/Other Measurements options

Option Description

NLTS Initial Non-Linear Transition Shift; measures NLTS caused by a transition in the

current bit cell which reverses the direction of the previous magnification

NLTS 1st Adjacent Measures NLTS caused by a transition in the previous bit cell which

opposes the transition in the current bit cell; also called the first adjacent

NLTS 2nd Adjacent Measures NLTS caused by a transition which is two bit cells before the

current bit cell; also called the second adjacent

NLTS Snapshot Provides a summary of NLTS measurements

SNR Signal-to-Noise Ratio; determines the ratio of the variance of the readback

signal to the readback noise and expresses the ratio in dB units

Asperity Large signal caused when the disk drive head strikes the media; the

application compares the mean value of TAA samples to the amplitudes of peak/trough pairs and saves values that exceed the Threshold option; also saves the sector number and time relative to the start of the waveform data record

Overwrite Determines the amount of residual signal remaining from a previous write

when new data is written to the same location

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Table 2- 7: NLTS/Other Measurements options (Cont.)

Option Description

Resolution Determines the ratio of a high-frequency TAA pattern to a low-frequency

TAA pattern, expressed as a percentage (write a low-frequency TAA pattern to a track, measure it, erase it, write a high-frequency TAA pattern to the same track, and measure again)

Baseline Shift Difference between the baseline of the positive pulse and the baseline of

the negative pulse

Figure 2--6 shows the parameter options for NLTS measurements.

Polynominal

Polynominal index

Figure 2- 6: NLTS Parameter options

Table 2--8 lists the NLTS Parameter options with a brief description of each.

Table 2- 8: NLTS Parameter options

Option Description

Pattern Dur Initial length of time for one repetition of the pseudo-random bit data pattern;

enter your best estimate

Dur Toler Tolerance (accuracy) of the initial value in the Pattern Dur option; a smaller

percentage helps the application take the measurement more quickl y

Poly Index Application uses x=2 to obtain condensed notations of selected pseudo-ran-

dom binary sequence polynominals; you should use the same polynominal that generates the data pattern written to the media; when you use the multipurpose knob, invalid polynominals do not appear as selections

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Basics Operations

NOTE. The application initially uses the estimated value that you enter for the Pattern Dur option. The application then uses autocorrelation to precisely measure the duration pattern and replaces the estimated value.

Figure 2--7 shows an example of how the application uses x = 2 to calculate the polynominal index.

Polynominal = x9+ x4+ 1 Polynominal index = 2

+ 24+ 1 = 529

Figure 2- 7: How the application calculates the polynominal index

Figure 2--8 shows the parameter options for the SNR measurement.

Figure 2- 8: SNR Parameter options

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Table 2--9 lists the SNR Parameter options with a brief description of each.

Table 2- 9: SNR Parameter options

Option Description

Pattern Dur Number of bits per pattern period for general patterned data, dependi ng on

what was previously recorded on the hard disk

For pseudo-random data of pseudo-noise type generated with shift registers (pseudo-random binary sequence), number of bits per pattern is 2 L is the order of the characteristic polynominal

Dur Toler Same as in Table 2--8

Bits/Pattern Periodic signals used for SNR measurements defined as isolated periodic

transitions (low frequency), isolated high-density periodic transitions (high frequency), or patterned data such as pseudo-random sequences; use two bits per pattern for low-frequency and high-frequency patterns

L-1

, where

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Basics Operations

The value for the Threshold option determines if the application identifies a signal as an asperity. Figure 2--9 shows the Threshold option.

Figure 2- 9: Asperity Parameter options

Configuring a Measurement

There are three Inputs menus: Inputs/Trigger, Inputs Filters, and Inputs General.

Inputs/Trigger. To configure the input waveforms for a measurement, go to the Inputs menu in the menu bar and choose Inputs/Trigger. Figure 2--10 shows the Inputs/Trigger menu.

Figure 2- 10: Inputs/Trigger menu

Table 1--3 on page 1--16 lists the default channel assignments. The application has the following Input Channels options:

H Read Signal: a waveform that performs a read operation from a sector

H Read Gate: a waveform that indicates the beginning of a read operation; the

application Trigger mode must be set to Read Gate to use this input

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H Sector Pulse: a waveform that indicates the beginning of a sector; the

application Trigger mode must be set to Sector to trigger with this and the Index Pulse inputs

H Index Pulse: a waveform that indicates the beginning of a track; the

application Trigger mode must be set to Index or to Sector to trigger with this input

Table 2--10 lists the Trigger options with a brief description of each.

Table 2- 10: Trigger options

Option Description

Mode

Sector Triggers on the Sector Pulse and Index Pulse inputs; uses oscilloscope

delayed triggers to monitor various sectors

Read Gate* Triggers on the Read Gate input; since delayed triggers are not used, you

must program the disk drive to sequence through a range of sectors and leave a delay that is long enough for the application to take a measurement

User* Uses the oscilloscope trigger exactly as specif ied

Index* Triggers on the Index Pulse input; oscilloscope delayed trigger is not used

Preamble** Time required to initialize a disk drive before signals become stable; the

duration of the preamble varies between disk drive manufact urers

Start Sector** Specifies the sector on which to start the measurement

Stop Sector** Specifies the sector on which to stop the measurement

* Refer to Setting up the Oscilloscope Trigger on page 1- 11.

** Only available when Sector is the trigger mode.

NOTE. For more information on how the application Trigger modes affect the oscilloscope trigger controls, refer to step 2 on page 1--13.

Filters. You can modify the Read Signal input by applying filters that block specific frequency bands. You can configure each filter as a Highpass filter to block out the low frequency band, or as a Lowpass filter to block out the high frequency band. You can also configure the filters by selecting a Slope and a Cutoff Frequency based on the sample rate.

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To configure a filter for a measurement, go to the Inputs menu in the menu bar and choose Filters. Figure 2--11 shows the Inputs Filters menu.

TDSDDM2 Disk Drive Measurements Application User Manual

Basics Operations

Figure 2- 11: Inputs Filters menu

Table 2--11 lists options for Filter 1 and Filter 2 with a brief description of each.

Table 2- 11: Filters options

Option Description

On/Off Enables the application to use a filter as defined by t he remaining options

Cutoff Freq Excludes frequencies above (Low pass filter) or below (High pass filter) the

value specified for measurements

Update Updates the Cutoff Freq value if you change the sample rate (Horizontal

Scale knob) of the oscilloscope

The Min and Max values show the range for the Cutoff Freq option; the Min value is 5% of the sample rate and the Max value is 35% of the sample rate

Type

High pass Blocks the low frequency band and passes on only the high frequency band

of the waveform

Low pass Blocks the high frequency band and passes on only the low frequency band

of the waveform

Slope Defines the slope of the filter in dB/octave units

Store In Selects the reference memory in which to store the filtered waveform, if any

Figure 2--12 shows the filter characteristics of the various filter options.

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Basics Operations

3dB

Cutoff freq.

Magnitude

3dB

Lowpass

Magnitude

3dB

Magnitude

Frequency

84 dB/Oct

72 dB/Oct

60 dB/Oct

Highpass

Slope

24 dB/Oct

12 dB/Oct

24 dB/Oct 36 dB/Oct 48 dB/Oct

Figure 2- 12: Filter characteristics

Using Both Highpass and Lowpass Filters. When you use both filters, the application first applies Filter 1 to the Read Signal input and then Filter 2. You should be aware that you can select a Cutoff Frequency value that filters out the entire waveform or all but a small amount of noise. Figure 2--13 shows the spectrum of the waveform passed to take measurements when you use both the Highpass and the Lowpass filters.

Pass band

3dB

Cutoff frequency

Lowpass

Magnitude

Frequency

Cutoff frequency Highpass

Figure 2- 13: Using both Highpass and Lowpass filters

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Basics Operations

Filtering Transient Responses. At the beginning and end of the filtered waveform, there will be a transient response caused by the response of the filter to a discontinuity. You can use Gating in the Inputs General menu to exclude the discontinuity from the measurement calculations. To do this, follow these steps:

1. Select Inputs> Filters> On> Store In and the desired reference memory, Ref1, Ref2, Ref3, or Ref4.

2. Select Single Mode and press

to start the measurement sequence.

3. Remove the Read Signal input waveform from the display. If the input is a channel, press the front-panel channel button to remove the waveform.

4. Observe the displayed Ref waveform and verify that the amplitude is correct.

You can see transient responses at the beginning and end of the waveform.

5. Select Inputs> General> Gating> On.

6. Move the vertical cursors so that there are no transient responses between

them; this excludes the transient responses from the measurement.

7. Press

to start the measurement sequence.

8. Repeat step 3 to remove the Read Signal waveform from the display.

9. Observe the displayed Ref waveform. If necessary, adjust the Cutoff

Frequency value; steeper slopes yield longer transient responses.

10. If necessary, repeat step 6.

11. Select Inputs> Filters> Store In> None. The application will display

measurement results faster when reference memories are not used.

Cutoff Frequency Values and Sample Rate. When you start the application, or recall the default setup, the application uses the current oscilloscope sample rate to calculate a Min and Max range for Cutoff Frequency values. The Min and Max range displays at the bottom of the Inputs Filter menu. The application also sets the Lowpass filter to 15% of the sample rate and the Highpass filter to 10%. You can adjust the Cutoff Frequency value within the Min and Max range.

When you change the sample rate and choose the Update command button, the Min value is set to 5% of the sample rate and the Max value is set to 35% for both filters. The application retains the value of the Cutoff Frequency if it is within the updated range. If the value is outside the updated range, the application adjusts the Cutoff Frequency to the closest value within the updated range.

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NOTE. If the value of the Cutoff Frequency is below the updated range, the application sets it to the Min value. If the value is above the updated range, the application sets it to the Max value.

To change the sample rate and adjust the filter frequencies, follow these steps:

1. Use the Horizontal Scale knob on the oscilloscope to change the sample rate.

2. Choose the Update command button for either filter. The Min and Max

values for both filters change relative to the new sample rate.

3. Adjust the Cutoff Frequency value according to your needs.

General. To configure the hysteresis or the gating for a measurement, go to the Inputs menu in the menu bar and choose General. Figure 2--14 shows the Inputs General menu.

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Figure 2- 14: Inputs General menu

Table 2--12 lists the General options with a brief description of each.

Table 2- 12: General options

Option Description

Hysteresis Filters out noise that could cause false identification of peaks; refer to Figure 1--9

on page 1--15 for more information

Gating Area between cursors on the waveform from which measurements are t aken

TDSDDM2 Disk Drive Measurements Application User Manual

Taking Measurements

Basics Operations

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 r eference or a math waveform as the source, you will need to recall and display the waveform before the application can take a measurement. For information on how to do this, refer to Recalling a Waveform File on page 2--26.

Remember to select Reset to set the results to zero if you change the oscilloscope Vertical or Horizontal time settings between measurements.

Taking New

Measurements

The Sequence Control menu is always accessible in the lower right part of the application display. Figure 2--15 shows the Sequence Control menu.

Start button

Reset button

Sequence Mode

Stop button Continue

button

Pause button

Figure 2- 15: Sequence Control menu

To acquire data from waveforms, follow these steps:

1. Select a Sequence mode. See Table 2--13.

Table 2- 13: Sequence Control menu

Option/button Description

Mode

Single

Free Run

Start/Continue button

If the input source is Ch1, Ch2, Ch3, or Ch4, the application acquires a new waveform(s); for all sources, the application performs measurements on the waveform(s) and stops

Repeatedly acquires the input waveform(s) and takes measurements

Starts to take measurements from the input waveform(s) When paused, continues taking measurements

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Table 2- 13: Sequence Control menu (Cont.)

Option/button Description

Pause button Pauses and resumes when you select the Continue button or stops when

you select the Stop button

Stop button Stops taking measurements

Reset button Resets all result values to zero

2. Press to start the measurement sequence.

NOTE. Do not change oscilloscope settings while a measurement is being taken since this can cause an invalid measurement.

Localizing Measurements

Analyzing the Results

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. Refer to Setting Up the Oscilloscope Trigger on page 1--11 for information on how to adjust the Record Length and Sample Rate in the Math> Spectral Controls menu (T tab) on the oscilloscope.

An Alternative Method. There is another way to control the amount of data to measure without using gated cursors or specifying a range of sectors. You can do this by adjusting the Preamble Duration in the application Sector menu and the Record Length or Horizontal Scale in the oscilloscope horizontal menu. By specifying both the starting point and the total length of the measurement in this way, you can effectively size the area of interest.

NOTE. If an error message displays because there are not enough cycles from which to take a measurement, you should increase the Record Length or the Horizontal Scale.

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You can view the results as statistics or graphically as a plot. Figure 2--16 shows an example of the results display formats.

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Basics Operations

NOTE. Stop the acquisition before viewing the results as plots if you are taking measurements in the Free Run mode.

Figure 2- 16: Results as statistics and as a Track Profile plot

You can also log the data to a .csv file for viewing in a text editing, spreadsheet, database, or data analysis program. Figure 2--17 shows an example of how a .csv file might look in a spreadsheet program.

Figure 2- 17: Example of viewing data in a .csv file

NOTE. Statistical results vary widely across the different measurements. Because of this, each measurement has a unique format for the statistics in a log file.

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Basics Operations

Viewing Statistics

Viewing Plots

To access the View Results menu, go to the View menu in the menu bar and choose Results. Refer to the Applications Examples section to see examples of statistical results for each type of measurement.

The statistical information that displays will vary by measurement. In general, the View Results menu contains statistical values for the mean, the maximum (Max), the minimum (Min), the standard deviation (StdDev), the SNR statistics (StatSNR), the number of peaks, troughs or peak/trough pairs used for the average values (num avg), and the sector number.

There is one plot format: Track Profile. The format plots the results such that the vertical axis represents the mean measurement value and the horizontal axis represents the measurement number.

To access the Plot Track Profile menu, go to the Plots menu in the menu bar and choose Track Profile. Figure 2--18 shows the Plot Track Profile menu.

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Figure 2- 18: Plot Track Profile menu

Table 2--14 lists the Plot Track Profile options with a brief description of each.

Table 2- 14: Plot Track Profile options

Option Description

On/Off Enables the application to plot track data

Store Profile In: Selects the reference memory in which to store data for the plot

Reset Clears all data in the plot

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Basics Operations

When the application trigger mode is set to Sector, the Plot Track Profile menu also contains the following readouts:

H Value at Cursor displays the measurement value and is in units relative to the

measurement (V, Mhz, dBs).

H Sector at Cursor displays the measurement number or the sector number at

the cursor

For more information on Track Profiles, refer to Creating and Viewing Track Profile Plots on page 2--45.

Clearing Results

To reset all results to zero, choose the Reset button in the Sequence Control menu. You do not have to wait for a measurement to complete to reset the results.

Saving the Results to a File

You can save most measurement results as statistics to a data log file.

NOTE. The application does not log results from the Overwrite or the Resolution measurements.

Logging Statistics

Logging saves the statistical results from measurements to a data log file. To access the Log Statistics menu, go to the Log menu in the menu bar and choose Statistics.

Figure 2--19 shows the Log Statistics menu.

Figure 2- 19: Log Statistics menu

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Basics Operations

Table 2--15 lists the Log Statistics options with a brief description of each.

Table 2- 15: Log Statistics options

Option/button Description

Logging Enables the application to save the results to a data log file

Clear Deletes the data log file for the selected measurement; you must

disable the logging before you can clear the contents of the data log file

Save Current Stores the current measurement results in a “comma separated

variable” formatted file (.csv file) that you can view at a later time

Log file name: Browse

Allows you to select the directory in which to save the data log file and to enter a name for the file; the extension must be .csv

Figure 2--20 shows an example of the Log file directory that displays when you select Browse.

Data Log File Format

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Figure 2- 20: Log file directory

The data log file consists of one header row and rows of logged information. The header row contains the application name, the version number of the application, and the date and time on which the file was created. The remaining rows contain information for the measurements. The information will vary with the measurements being logged.

TDSDDM2 Disk Drive Measurements Application User Manual

Viewing a Data Log File

Basics Operations

NOTE. If you are using a GPIB program to execute the application, such as in automated test environments, you can add your own annotation through the logAnnotate GPIB command. You can add information consisting of up to 20 characters; the custom information will appear after the date and time in the rows of logged data.

You can view the .csv data log file (comma separated variable format) in a text editing, spreadsheet, database, or data analysis program for further analysis.

NOTE. You can use Notepad or Wordpad to quickly view the results in the data log file.

You must take measurements in Free Run mode to accumulate data points and store them in one data log file. Figure 2--17 on page 2--17 shows an example of a .csv file in a spreadsheet program.

Saving and Recalling Setups

You can use the Save/Recall Measurements menu to save and to recall different configuration setups. To access the Save/Recall Measurements menu, go to the Measurements menu in the menu bar and choose Save/Recall.

Figure 2--21 shows the Save/Recall Measurements menu.

Figure 2- 21: Save/Recall Measurements menu

Table 2--16 lists the Save/Recall Measurements options with a brief description of each.

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Basics Operations

Table 2- 16: Save/Recall Measurements options

Option/button Description

Save Allows you to select a file in which to save the application setup file

Recall Allows you to select a file from which to recall the application setup

Default Recalls the Default application setup values

File name for Save/Recall Displays the name of the last file used to save or recall a setup

NOTE. The Measurements > Save/Recall function includes the settings of the oscilloscope application. When you exit the application, you can choose whether to restore oscilloscope settings to those present before starting the application.

Do not edit the .ini or the .set files, or recall setup files not generated by the application, since this can cause the application to become unstable.

Saving a Setup

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

1. Select Measurements > Save/Recall.

2. Select the Save button. Figure 2--22 shows an example of how the directory

displays when you select the Save button.

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Figure 2- 22: Save directory

3. Select the directory in which the setup file will be saved.

TDSDDM2 Disk Drive Measurements Application User Manual

Basics Operations

4. Select or enter a file name. The application appends a .ini extension to the name of setup files.

5. Choose Save.

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.

Recalling a Saved Setup

To recall the application settings from a saved setup file, follow these steps:

1. Select Measurements > Save/Recall.

2. Select the Recall button. Figure 2--22 shows an example of how directory

displays when you select the Recall button.

Figure 2- 23: Recall directory

3. Select the directory from which the setup file will be recalled.

4. Select or enter a setup file name.

5. Choose Recall.

NOTE. The application also recalls the oscilloscope setup from a .set file when you recall an application setup.

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Basics Operations

Recalling the Default

Setup

Exiting the Application

To recall the application settings from the Default setup file, follow these steps:

1. Select Measurements > Save/Recall.

2. Choose Default.

To exit the application, choose Exit. When you exit the application, you can select 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. Figure 2--24 shows the Exit menu.

Restore oscilloscope setup option

Figure 2- 24: Exit menu

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TDSDDM2 Disk Drive Measurements Application User Manual

Tutorial

This tutorial teaches you how to set up the application, take a measurement, view the results, and log the results. Further operating information is located in the Operating Basics section.

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

H Set up the oscilloscope

H Start the application

H Recall a waveform file

NOTE. Figures that show the display of an oscilloscope are from a TDS7104; there may be minor differences if you work through this tutorial with another type of oscilloscope.

Setting Up the Oscilloscope

Starting the Application

To set up the oscilloscope, follow these steps:

1. Go to the File menu in the menu bar and select Recall Default Setup to set the oscilloscope to the default factory settings.

2. Press the individual CH 1, CH 2, CH 3, and CH 4 buttons as needed to remove active waveforms from the display.

To perform these lessons, the application must be installed and enabled on the oscilloscope. See Installation on page 1--5. To start the application, go to the File menu in the oscilloscope menu bar and select Run Application> Disk Drive Measurements. Figure 2--25 shows how the application starts up and displays.

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Tutorial

Figure 2- 25: Starting the application

Recalling a Waveform File

The application includes a TAA waveform that you can use with this tutorial. The taapw50.wfm file is from a Read Signal.

To recall the taapw50.wfm file to Ref1 on to the oscilloscope, follow these steps:

1. Go to the File menu in the menu bar and access Reference Waveforms> Reference Setup. Figure 2--26 shows the Ref tabs.

Figure 2- 26: Oscilloscope reference waveform setup

2. Select the Ref 1 tab and Recall. Choose the c:\TekApplications\tdsddm2\waveforms directory. Figure 2--27 shows a list of waveform files that appear.

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TDSDDM2 Disk Drive Measurements Application User Manual

Figure 2- 27: Waveform directory to recall reference waveforms

3. Select the taapw50.wfm file and Recall.

Tutorial

Taking a TAA Measurement

In this example, you will learn how to use the application to take a Track Average Amplitude (TAA) measurement. To take a TAA measurement, refer to Figure 2--28, and follow these steps:

1. To return to the application, choose the App button in the Menu bar.

2. Select Inputs> Input/Trigger> Input Channels> Read Signal> Ref 1.

Figure 2--28 shows the Input/Trigger menu setup.

Figure 2- 28: Inputs/Trigger menu setup

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Tutorial

3. Press

Start button

Single mode

to start the acquisition as shown in Figure 2--29.

Figure 2- 29: Taking a measurement

Figure 2--30 shows the statistical results.

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Figure 2- 30: TAA lesson: statistical results

TDSDDM2 Disk Drive Measurements Application User Manual

Saving the Results to a Data Log File

To save the measurement results to a data log file, follow these steps:

1. Go to the Log menu in the menu bar and select Statistics. Figure 2--31 shows an example of the default application directory and log file name.

Tutorial

Viewing a Data Log File

Figure 2- 31: Log Statistics menu with default file name

2. Select Logging On.

3. Press

4. Select Logging Off before viewing the data log file.

5. Exit the application.

To view the data log file in a text editing application, such as Wordpad, follow these steps:

1. From the tool bar, select Start icon> Programs> Accessories> Wordpad.

2. Select File> Open.

3. Locate the C:\TekApplications\tdsddm2\data directory.

4. Select All Documents (*.*) for the Files of Type.

to start the acquisition.

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Tutorial

Figure 2- 32: Log file with default file name

5. Select the TAA.csv file and Open. Figure 2--33 shows the TAA.csv file viewed in Wordpad.

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Figure 2- 33: TAA.csv file viewed in Wordpad

You can also import the .csv file to a DOS-based personal computer and then view the data log file with a spreadsheet, database, or data analysis program.

TDSDDM2 Disk Drive Measurements Application User Manual

Stopping the Tutorial

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

To save the application setup and stop your session, refer to Saving a Setup on page 2--22 and to Exiting the Application on page 2--24.

ReturningtotheTutorial

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 on page 2--23.

Tutorial

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Tutorial

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TDSDDM2 Disk Drive Measurements Application User Manual

Application Examples

This section presents many application examples. The simplified examples highlight the application measurements and give you ideas on how to use the application to solve your own test problems.

H Measuring TAA

H Measuring PW50

H Measuring Asperity

H Measuring Overwrite

H Measuring Resolution

H Measuring Baseline Shift

H Measuring NLTS

H Measuring SNR

H Creating and viewing track profiles

To use these examples, you must have the TDSDDM2 application installed and enabled on the oscilloscope, the probes connected to your disk drive system under test (SUT), and the configuration tasks performed as needed for your SUT. For information, see Installation on page 1--5 and Configuration on page 1--11.

To start the application, refer to page 2--25.

NOTE. Figures that show the display of an oscilloscope are from a TDS7104; there may be minor differences if you are using another type of oscilloscope.

The application includes waveform files that you can recall to a reference memory to try out each example in this section. Table 2--17 lists the waveform file names.

Table 2- 17: Waveform files and application examples

File name Measurement File name Measurement

taapw50.wfm TAA and PW50 asperity.wfm Asperity

ovlosig.wfm Overwrite baselineShift.wfm Baseline Shift

ovhisig.wfm Overwrite x9x4x1.wfm NLTS and SNR

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Application Examples

Configuring a Measurement

You can configure any measurement to help you analyze measurement results. The application includes the following possible configurations:

H Taking measurements from a range of sectors

H Adding a limit test

H Using cursors (gating)

H Specifying hysteresis to filter out noise

H Using filters to focus the application on specific parts of a waveform

Specifying a Range of

Sectors

Specifying a Limit Test

To specify a range of sectors from which to take measurements, follow these steps:

1. Select Inputs> Inputs/Trigger> Trigger Mode> Sector.

2. Select Start Sector> (number).

3. Select Stop Sector> (number).

4. Set the Preamble option. Use the multipurpose knob, and select a value that

is greater than the actual signal preamble duration. This ensures that the preamble is not acquired and is not included in the measurement.

To use limit testing to include a pass/fail measurement result, follow these steps:

1. Select Limit Test On.

2. Use the multipurpose knob to set a value for the Upper Limit option that is

appropriate for your SUT.

3. Use the multipurpose knob to set a value for the Lower Limit option that is appropriate for your SUT.

The Asperity measurement does not need to test limits.

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Specifying Gating

Instead of measuring around the entire track, you can use cursor gating to localize the measurement. To specify gating, follow these steps:

1. Select Inputs> General> Gating On.

2. In the oscilloscope program, position the cursors to bound the part (on either

side) of the waveform that you want to measure.

3. Select App to return to the application.

TDSDDM2 Disk Drive Measurements Application User Manual

Application Examples

Specifying Hysteresis

Specifying a Filter

You can use the Hysteresis option to avoid identifying noise as actual signals.

To specify hysteresis, select Inputs/General> Hysteresis and use the multipurpose knob to set a value for the Hysteresis option that is appropriate for your SUT.

The hysteresis value, in divisions, is reflected above and below the waveform baseline. For example, if you choose a value of 1.5 divs, the hysteresis level ranges from --1.5 divs to +1.5 divs.

You can modify the Read Signal input by applying filters that block specific frequency bands. This removes information from the measurement that is not useful to analyze. To use Filters, refer to page 2--10.

Using Reference Waveforms

To attain the results shown in each figure (except for Track Profile) from the specified .wfm file, you need to define the following general setup:

1. In the oscilloscope menu bar, select File> Recall Default Setup.

2. Recall the appropriate .wfm file to one of the reference memories; refer to

page 2--26.

Measuring TAA

3. Select Measurements> Save/Recall> Recall default values.

4. Select the appropriate measurement from either the TAA/PW50 or NLTS/

Other Measurements menus.

5. Select the reference memory as the Read Signal input option in the Inputs/ Trigger menu.

In this example, you can measure the track average amplitude (TAA). To take a TAA measurement, follow these steps:

1. Select Measurements> TAA/PW50> T AA.

2. To configure the measurement, refer to Configuring a Measurement on

page 2--34.

3. Set the Sequence Mode to Single or Free Run.

4. Select

5. When the measurement is complete, the statistical results automatically

display. Figure 2--30 on page 2--28 shows an example of TAA measurement results based on the taapw50.wfm file.

to start the measurement.

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Application Examples

Measuring PW50

In this example, you can measure the pulse width at 50% (PW50). To take a PW50 measurement, follow these steps:

1. Select Measurements> TAA/PW50> PW50.

2. To configure the measurement, refer to Configuring a Measurement on

page 2--34.

3. Set the Sequence Mode to Single or Free Run.

4. Select

5. When the measurement is complete, the statistical results automatically

display. Figure 2--34 shows an example of PW50 measurement results based on the taapw50.wfm file.

to start the measurement.

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Figure 2- 34: PW50 measurement results example

TDSDDM2 Disk Drive Measurements Application User Manual

Measuring Asperity

Application Examples

In this example, the oscilloscope will detect asperities. To take an Asperity measurement, follow these steps:

1. Select Measurements> NLTS/Other> Asperity.

2. Use the multipurpose knob to set a value for the Threshold option. The

recommended initial setting is at least twice the peak value of the signal. If the signal crosses this level, it is counted as an asperity. No additional asperities are counted until the signal crosses zero volts again.

3. If you want to change trigger settings or localize the measurement, do so now. The application defaults to the settings specified in the Trigger menu. For further information, see Setting Up the Application Trigger on page 1--12.

4. Set the Sequence Mode to Single.

5. Select

6. When the measurement is complete, a list of asperities, sector locations and

time locations automatically display. Figure 2--38 shows an example of the results based on the asperity.wfm file with the Asperity Threshold as 1.5 V.

to start the measurement.

Figure 2- 35: Asperity measurement results example

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Application Examples

Measuring Overwrite

In this example, you can measure the overwrite amount of residual signal remaining from a previous write when new data is written to the same location. The application overwrites part of the disk drive to take this measurement.

To measure the overwrite, you will also need a personal computer.

NOTE. Select a record length on the oscilloscope of 5,000 or more for Overwrite measurements. This increases the frequency and the measurement resolution.

To take an Overwrite measurement, follow these steps:

1. Erase the track by using a permanent magnet or using the PC to perform a DC erase for many revolutions on a three band track of overlapping tracks centered on the specified radius.

2. Write a low-frequency data pattern of isolated pulses to the track.

To try out this example, recall the ovlosig.wfm file to a reference memory.

3. Select Measurements> NLTS/Other> Overwrt.

4. Set the Sequence Mode to Single or Free Run.

5. Select

of the signal and then pauses.

The Sequence Control displays Paused For Action and the results display PASS 1 in the upper right corner. Figure 2--36 shows an example of the Overwrite measurement Pass 1 results based on the ovlosig.wfm file

6. Without erasing the previous data, overwrite the track with a high-frequency data pattern.

If you are trying out this example, you can overwrite the ovlosig.wfm file with the ovhisig.wfm file. To do this, recall the ovhisig. wfm file to the same reference memory used for the ovlosig.wfm file.

7. Select

When the measurement is complete, the statistical results automatically display. Figure 2--37 shows an example of the Overwrite measurement Pass 2 results based on the ovlosig.wfm and ovhisig.wfm files.

to start the measurement. The application measures the magnitude

to continue. The results display PASS 2 in the upper right corner.

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TDSDDM2 Disk Drive Measurements Application User Manual

Application Examples

Figure 2- 36: Overwrite measurement, PASS 1 example

Figure 2- 37: Overwrite measurement results, PASS 2 example

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Application Examples

Measuring Resolution

In this example, you can measure the resolution of a head and disk combination. The application determines the ratio of two TAA measurements of a lowfrequency pattern to a high-frequency pattern. The result is a percentage.

To measure the resolution, you will also need a personal computer.

To take a Resolution measurement, follow these steps:

1. Erase the track by using a permanent magnet or using the PC to perform a DC erase for many revolutions on a three band track of overlapping tracks centered on the specified radius.

2. Use the PC to write a high-frequency data pattern of isolated pulses to the disk.

3. Select Measurements> NLTS/Other> Resltn.

4. Set the Sequence Mode to Single.

5. Select

6. Erase the track again as described in step 1.

7. Use the PC to write a low-frequency data pattern of isolated pulses to the

8. Select

9. When the measurement is complete, the statistical results automatically

An example is not included because it is similar to the Overwrite measurement.

Measuring Baseline Shift

In this example, you will measure the difference between the baseline of a positive pulse and the baseline of a negative pulse. To take a Baseline Shift measurement, follow these steps:

to start the measurement. The oscilloscope performs a TAA

measurement of the high-frequency pattern and then pauses.

The Sequence Control displays Paused For Action and the results display PASS 1 in the upper right corner.

disk.

to continue. The results display PASS 2 in the upper right corner.

display.

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1. Select Measurements> NLTS/Other> Baseline Shift.

2. Set the Sequence Mode to Single or Free Run.

3. Select

to start the measurement.

TDSDDM2 Disk Drive Measurements Application User Manual

Application Examples

4. When the measurement is complete, the statistical results automatically display. Figure 2--38 shows an example of a Baseline Shift measurement results based on the baselineShift.wfm file.

Measuring NLTS

Figure 2- 38: Baseline Shift measurement results example

To take NLTS measurements, your setup must meet the following requirements:

H The waveform selected for the measurement must correspond to a bit pattern

written on the disk generated using a valid (maximum length) polynomial; among other things, this might require that you disable RLL encoding.

H The disk drive waveform must have at least 1,000 samples.

H There must be at least eight samples per bit.

H The oscilloscope must acquire at least three periods of the pattern where the

period is the amount of time before the pseudo-random bit pattern begins to repeat itself; to do this depends on the sample rate of the oscilloscope, the estimated value that you enter for the Pattern Dur option, and the number of bits per period (based on the polynominal used).

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Application Examples

To take an NLTS measurement, follow these steps:

1. Select Measurements> NLTS/Other> NLTS Initial.

2. Select Pattern Dur and specify a value.

The pattern duration is the length of time of the period of a pseudo-random data pattern in the readback signal. The pattern duration can be an estimate, as long as the estimate is within the tolerance that you specify in step 3; the application will measure the exact duration of the pattern. (Due to variations in revolution speed between disk drives, specifying the pattern duration is necessarily an estimate.)

3. Select Dur Toler and specify the tolerance of your pattern duration estimate (up to 30%). Using a tighter tolerance reduces measurement time.

NOTE. If you know the exact duration of the data pattern, you can reduce the measurement time by specifying a Duration Tolerance of 0%. The application will use the Pattern Duration that you specify without attempting to adjust to the actual duration of the pseudo-random pattern.

4. Select Poly Index and use the multipurpose knob to specify the pseudorandom binary sequence polynomial. This should be the same polynomial used to generate the data pattern written to the media.

For valid results, it is essential that you specify the same polynominial as the one used for recording data on the hard disk (media). Both polynomials must be valid according to the 1995 IDEMA “white paper.”

The NLTS measurement is based on autocorrelation and uses a polynomial to generate a pseudo-noise sequence. Select the polynomial using the multipurpose knob; all selections provide a valid pseudo-noise sequence. (The application removes invalid polynomials from the selection set.) The polynomial index value on the scale is a condensed notation of the selected polynomial, obtainable by making x=2. For example:

Polynominal = x9+ x4+ 1

Polynominal index = 2

+ 24+ 1 = 529

5. If you want to change trigger settings or localize the measurement, do so now. The application defaults to the settings specified in the Trigger menu. For further information, see Setting Up the Application Trigger on page 1--12.

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6. Set the Sequence Mode to Single or Free Run.

7. Press

to start the acquisition.

TDSDDM2 Disk Drive Measurements Application User Manual

Application Examples

8. When the measurement is complete, the statistical results automatically display. Figure 2--39 shows an example of NLTS Initial measurement results based on the x9x4x1.wfm file.

Measuring SNR

Figure 2- 39: NLTS measurement results example

To take SNR measurements, your setup must meet the following requirements:

H The disk drive waveform must have at least 1,000 samples

H There must be at least eight samples per bit

H The oscilloscope must acquire at least three periods of the pattern where the

To take an SNR measurement, follow these steps:

1. Select Measurements> NLTS/Other> SNR.

2. Select Pattern Dur and specify a value.

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Application Examples

The pattern duration is the length of time of the period of a pseudo-random pattern in the readback signal. The pattern duration can be an estimate, as long as the estimate is within the tolerance that you specify in step 3; the application will measure the exact duration of the pattern. (Due to variations in revolution speed between disk drives, specifying the pattern duration is necessarily an estimate.)

3. Select Dur Toler and specify the tolerance of your pattern duration estimate (up to 30%). Using a tighter tolerance reduces measurement time.

4. Select Bits/Pattern and specify a value.

Periodic signals used for the SNR measurement are isolated low-density periodic transitions (low frequency), isolated high-density periodic transitions (high frequency), or patterned data such as pseudo-random sequences.

H If you are using a high-frequency pattern consisting of constantly spaced

isolated transitions, use two bits per pattern for the low frequency and high frequency patterns.

H For general patterned data, use the number of bits per pattern period,

depending on what was previously recorded on the disk.

H For pseudo-random data of pseudo-noise type generated with shift

registers (pseudo-random binary sequence), the number of bits per pattern is 2 For example, for a 9th order polynomial the value would be 511 (2 for a 7th order polynomial the value would be 127 (2

-- 1, where L is the order of the characteristic polynomial.

--1).

6. Set the Sequence Mode to Single.

7. Press

to start the acquisition.

8. When the measurement is complete, the statistical results automatically display. Figure 2--40 shows an example of SNR measurement results based on the x9x4x1.wfm file.

--1);

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TDSDDM2 Disk Drive Measurements Application User Manual

Application Examples

Figure 2- 40: SNR measurement results example

Creating and Viewing T rack Profile Plots

Track Profile plots are reference memory waveforms that contain a history of measurement results. You can use track profiles to observe sector-to-sector variations in measurements and to identify the location of flaws within a track.

NOTE. The result of creating a Track Profile plot from a reference waveform is a short straight line.

To create and view a Track Profile plot, follow these steps:

1. Select a measurement from either the TAA/PW50 or NLTS/Other Measurements menus.

2. To configure the measurement, refer to Configuring a Measurement on page 2--34.

3. Select Inputs> General> Gating Off.

4. Select Plot> Track Profile> Store Profile In:> any reference memory.

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Application Examples

NOTE. As soon as you select Plot> Track Profile> On, the application deletes all information contained in the selected reference memory.

5. Select Plot> Track Profile> On.

6. Set the Sequence Mode to Single or Free Run.

7. Select

statistics and are stored as a track profile plot in the reference memory selected in step 4.

Figure 2--41 shows an example of a Track Profile plot from a TAA measurement.

to start the measurement. The measurement results are saved as

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Figure 2- 41: Track Profile plot example

8. If you use the Sector Trigger mode, you can also use the vertical cursors on the oscilloscope. To use the vertical cursors, press the Cursors front-panel button. The default Cursor Type is V Bars.

9. Select App to return to the application. Figure 2--42 shows an example of a Track Profile plot with vertical cursors.

TDSDDM2 Disk Drive Measurements Application User Manual

Application Examples

You can view the results of each execution of the measurement algorithm by moving the cursor along the Track Profile plot. The Value at Cursor and Sector at Cursor readouts show the measurement results at the current location of the cursor. The Value at Cursor readout is in units relative to the measurement ( such as V, MHz, dBs).

NOTE. The readout values are only available with the current Track Profile plot; they are not available with waveforms that are recalled as a reference memory. You also must select the Sector Trigger mode to use cursors with Track Profiles.

Figure 2- 42: Track Profile plot with cursors

10. To save the reference waveform containing the plot, follow these steps:

a. Go to the File menu in the menu bar of the oscilloscope and access

Reference Waveforms> Reference Setup.

b. Select the appropriate Ref tab and Save Wfm to File.

11. To clear the Track Profile plot, select Reset.

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Application Examples

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TDSDDM2 Disk Drive Measurements Application User Manual

GPIB Program Example

This section contains an example of a GPIB program that can execute the TDSDDM2 application. The oscilloscope hard disk and the optional applications compact disc both contain this program in the ddm2ctrl.c file. The file resides on the hard drive in the C:\Program Files\TekApplications\tdsddm2 directory.

Guidelines

Your GPIB program should comply with the following guidelines:

H The application startup must complete before sending additional GPIB

commands to the application (see example).

H The measurements cycle must complete before data is queried (see example).

H The error variable should be checked to ensure that an error has not occurred

because of a measurement command problem.

Program Example

This example shows how a GPIB program might execute the application to do the following tasks:

H Start the application

H Select a measurement

H Select an input

H Define a waveform

H Enable the logger

H Take a measurement

H Check for an error

H Exit the application

Refer to Appendix B: GPIB Command Syntax for a complete list of the GPIB command syntax with the arguments, variables, and variable values.

NOTE. GPIB commands are case and space sensitive.

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GPIB Program Example

/* C Program Example: TDSDDM2 GPIB control */ /* ====================================================================

* This sample program is for Tektronix Java application TDSDDM2 -* Disk Drive Measurements * * Note1: In order to build the .exe correctly, copy gpib-32.obj from * ”C:\Program Files\National Instruments\GPIB\NI488\LangInt\C\” or * ”C:\Program Files\GPIB-NT\LangInt\C\ to * the workspace. * */

#include <string.h> #include <stdio.h> #include <sys/timeb.h> #include <windows.h> #include ”C:\GPIB-NT\LangInt\C\decl-32.h”

int start_application(/* in */ int scope); int do_single_test(/* in */ int scope);

void main (void) {

char read_buffer [100] = ””; char write_buffer [100] = ””; int scope; int status;

* Open session for IBIC

*/ scope = ibfind (”DEV2”); status = ibpad (scope, 1); status = ibtmo (scope, T10s); status = ibwrt (scope, write_buffer, strlen (write_buffer));

* Start Application

*/ if (start_application(scope)){

printf (”Application is started up!\n”);

* Turn on a measurement (TAA)

*/ sprintf (write_buffer, ”%s”, ”Variable:value \”measurement\”,\”TAA\””); status = ibwrt (scope, write_buffer, strlen (write_buffer)); /*

* Select Source Type -- REF

*/ sprintf (write_buffer, ”%s”, ”Variable:value \”readSignal\”, \”Ref1\””);

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TDSDDM2 Disk Drive Measurements Application User Manual

status = ibwrt (scope, write_buffer, strlen (write_buffer));

* Recall Waveform to Ref */

sprintf (write_buffer, ”%s”, ”recall:waveform

\”c:\\TekApplications\\tdsddm2\\waveforms\\diskdrive.wfm\”, REF1”);

status = ibwrt (scope, write_buffer, strlen (write_buffer));

* Display Ref1

*/ sprintf (write_buffer, ”%s”, ”select:ref1 on”); status = ibwrt (scope, write_buffer, strlen (write_buffer));

* Turn on Log Statistics for TAA measurement

*/ sprintf (write_buffer, ”%s”, ”Variable:value \”TAAloggerState\”,\”On\””); status = ibwrt (scope, write_buffer, strlen (write_buffer)); /*A Timer is needed after setting the loggerState on*/

Sleep(2000);

GPIB Program Example

* Do a single test

if (do_single_test(scope)){

* Set Measurement for which you want to query test result -- TAA

*/ sprintf (write_buffer, ”%s”, ”Variable:value \”resultFor\”,\”TAA\””); status = ibwrt (scope, write_buffer, strlen (write_buffer));

/*A Timer is needed after setting the measurement to be queried*/ Sleep(500); /*

* Query mean result

*/ sprintf (write_buffer, ”%s”, ”Variable:value? \”mean\””); status = ibwrt (scope, write_buffer, strlen (write_buffer)); status = ibrd (scope, read_buffer, sizeof (read_buffer));

if (ibcnt != 3) { /* It’s not an empty string */

read_buffer [ibcnt] = 0; /* Get rid of extra characters */ printf (”Mean TAA = ”);

TDSDDM2 Disk Drive Measurements Application User Manual

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GPIB Program Example

printf (”%s”, read_buffer); }

}

else

printf (”*** Fail to query result ***\n”);

} else{

printf (”*** Fail to start Application ***\n”); return;

}

* Display Off for Ref1 before exiting

*/ sprintf (write_buffer, ”%s”, ”select:ref1 off”); status = ibwrt (scope, write_buffer, strlen (write_buffer));

* Exit application

*/ printf (”Exit application!\n”); sprintf (write_buffer, ”%s”, ”Variable:value \”application\”,\”exit\””); status = ibwrt (scope, write_buffer, strlen (write_buffer));

* Program Ending

*/ printf (”Program Terminating Normally\n\n”);

return;

}

/*--------------------------------------------------------------------------

* Function: start_application * Argument: scope * Return: 1 if success, 0 otherwise * * This function starts the application and comfirms the completion of startup */ int start_application(/* in */ int scope) {

char read_buffer [100]; char write_buffer [100]; char app_name[30] = ”\”tdsddm2\”\n”; int status;

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TDSDDM2 Disk Drive Measurements Application User Manual

GPIB Program Example

int timer = 0; int i = 0;

* Has application already been started?

*/ sprintf (write_buffer, ”%s”, ”Variable:value? \”application\””); status = ibwrt (scope, write_buffer, strlen (write_buffer)); status = ibrd (scope, read_buffer, sizeof (read_buffer)); read_buffer [ibcnt] = 0; /* Get rid of extra characters */

if (strcmp(app_name, read_buffer) == 0){

return 1; /* Application is running, don’t need to do anything */

}

* If application is not started up, start it and wait for application to completely

* start up

sprintf (write_buffer, ”%s”, ”Application:activate \”Disk Drive Measurements V2\””); status = ibwrt (scope, write_buffer, strlen (write_buffer));

printf (”Starting application, please wait...\n”);

while (strcmp(app_name, read_buffer) != 0){

timer = timer + 2; if (timer > 45) { /* The application normally take 24 seconds to start up */

printf (”***Application start up time out***\n”); return 0; /* Something is wrong if application does not start up in 30s */

} sprintf (write_buffer, ”%s”, ”Variable:value? \”application\””); status = ibwrt (scope, write_buffer, strlen (write_buffer)); status = ibrd (scope, read_buffer, sizeof (read_buffer)); read_buffer [ibcnt] = 0;/* Get rid of extra characters */

Sleep(2000);

} /* Application start up! */

return 1;

}

/*--------------------------------------------------------------------------

* Function: do_single_test * Argument: scope * Return: 1 if success, 0 otherwise * * This function does a single measurement */ int do_single_test(/* in */ int scope) {

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GPIB Program Example

char read_buffer [100]; char write_buffer [100]; char state[10] = ”\”Ready\”\n”; int status; int timer = 0; int i = 0;

* Start measurement */

printf (”Do a single test...\n”);

sprintf (write_buffer, ”%s”, ”Variable:value \”sequencerState\”,\”Sequencing\””); status = ibwrt (scope, write_buffer, strlen (write_buffer));

do{

timer = timer + 2; if (timer > 60) {/* Assuming a single test takes less than 60 seconds */

printf (”***Test time out***\n”); return 0; /* Something is wrong if sequencerState does not come back

* to Ready */ } sprintf (write_buffer, ”%s”, ”Variable:value? \”sequencerState\””); status = ibwrt (scope, write_buffer, strlen (write_buffer)); status = ibrd (scope, read_buffer, sizeof (read_buffer)); read_buffer [ibcnt] = 0;/* Get rid of extra characters */

Sleep(2000); }while (strcmp(state, read_buffer) != 0);

}

return 1;

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TDSDDM2 Disk Drive Measurements Application User Manual

Reference

Menu Structure

TAA/PW50

Measurements

NLTS/other Save/Recall Minimize

Figure 3--1 shows the relationship of the application-specific menus.

TAA TAA+ TAA - TAA Snap shot PW50 PW50+ PW50-PW50 Snap shot

NLTS Initial NLTS 1st Adj NLTS 2nd Adj NLTS Snap shot SNR Asperity Overwrite Resolution Baseline Shift

Limit Test

NLTS Parameters

SNR Parameters

On/Off Upper Limit Lower Limit

Pattern Duration Duration Tolerance Polynomial Index

Pattern Duration Duration Tolerance Bits per pattern

Inputs

View

*Displays numeric values only

Inputs/Trigger Filter General

Results

Track ProfilePlot

Save Recall Default

Read Signal Sector Pulse Read Gate Index Pulse

Mode Start Sector Stop Sector Preamble Duration

Filter1 Filter 2

Hysteresis Gating

On/Off Store Profile In Value at Cursor* Sector at Cursor* Reset

Asperity Parameter

Threshold

File name [Browse]

Sector Read Gate User Index

Cutoff Freq Update Type Slope Store In

Figure 3- 1: Menu structure

TDSDDM2 Disk Drive Measurements Application User Manual

3- 1

Menu Structure

Figure 3--2 shows the structure of the Log, Help, and Sequence Control menus.

Log

Help

Log Staistics

Contents and Index About TDSDDM2

Clear Save Current Log File Name [Browse]

Sequence Mode

Sequence Control

Start/Continue Pause Stop Reset

Figure 3- 2: Menu structure (continued)

Single Acq Free Run

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TDSDDM2 Disk Drive Measurements Application User Manual

Parameters

Measurements Menu

This section describes the TDSDDM2 application parameters. You should refer

to the user manual for your oscilloscope for operating details of other controls,

such as front-panel buttons.

Refer to Appendix D: GPIB Command Syntax for a complete list of the GPIB

command syntax with the arguments, variables and variable values that

correspond to the TDSDDM2 parameters.

NOTE. Incremental unit values shown are valid when the FINE button is enabled

on the oscilloscope.

There are four Measurements menu items: TAA/PW50, NLTS/Other, Save/Re-

call, and Minimize.

TAA/PW50 Menu

The options in the TAA/PW50 Measurements menu are:

H TAA, default

H TAA+

H TAA --

H TAA Snapshot

H PW50

H PW50+

H PW50--

H PW50 snapshot

Table 3--1 lists the parameters for the Limit Test area for each measurement and

the selections or range of values available for each.

TDSDDM2 Disk Drive Measurements Application User Manual

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Parameters

Table 3- 1: TAA/PW50 Limit Test area parameters

Measurement Option Selections Default setting

All On/Off On, Off On

TAA, TAA+, TAA Snapshot Upper Limit

Lower Limit

TAA -- Upper Limit

Lower Limit

PW50, PW50+, PW50--, PW50 Snapshot

NLTS/Other Menu

Upper Limit

Lower Limit

The options in the NLTS/Other Measurements menu are:

H NLTS Initial

H NLTS 1st Adj

H NLTS 2nd Adj

H NLTS Snapshot

H SNR

H Asperity

H Overwrite

0Vppto 10.0 Vppin units of 1 mV

--10.0 Vppto0Vppin units of 1 mV

0 s to 1.0 s in units of 50 ps

10.0 V

0.0 V

--10.0 V

1.0 s

H Resolution

H Baseline shift

Table 3--2 lists the parameters for the Limit Test area for each measurement and the selections or range of values available for each.

Table 3- 2: NLTS/Other Limit Test area parameters

Measurement Option Selections Default setting

All* On/Off On, Off On

NLTS Initial, NLTS 1st Adj, NLTS 2nd Adj, NLTS Snapshot

3- 4

Upper Limit

Lower Limit

--100% to 100% in units of 0.1%

100%

--100%

TDSDDM2 Disk Drive Measurements Application User Manual

Table 3- 2: NLTS/Other Limit Test area parameters (Cont.)

Measurement Default settingSelectionsOption

SNR Upper Limit

--20.0 dB to 100 dB in units of 0.1 dB

Parameters

100.0 dB

Lower Limit

Baseline Shift Upper Limit

Lower Limit

Overwrt Upper Limit

Lower Limit

Resltn Upper Limit

Lower Limit

*There is no Limit Test area for the Asperity measurement.

--20.0 dB to 100 dB in units of 0.1 dB

-- 5 . 0 Vppto 10.0 Vppin units of 1 mV

0 dB to 100 dB in units of 0.01 dB

0.1% to 200% in units of 0.1%

Table 3--3 lists the NLTS Parameters area and the selections or range of values

available for each.

Table 3- 3: NLTS Parameters area

Option Selections Default setting

Pattern Dur 1.0 ns to 1.0 ms in units of 1.0 ns 9.922 s

Dur Toler 0% to 30% in units of 1% 5%

Poly Index 19 to 4073 529

--20.0 dB

10.0 V

0.0 V

100.0 dB

0.0 dB

200%

100m%

Table 3--4 lists the SNR Parameters area and the selections or range of values

available for each.

Table 3- 4: SNR Parameters area

Option Selections Default setting

Patten Dur 1.0 ns to 1.0 ms in units of 1.0 ns 9.922 s

Dur Toler 0% to 30% in units of %1 5%

Bits/Pattern 1 to 8191 511

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Parameters

Table 3--5 lists the Asperity Parameter area and the range of values.

Table 3- 5: Asperity Parameter area

Option Selections Default setting

Threshold 0.0 V to 10.0 V in units of 10 mV 2.0 V

Save/Recall Menu

Minimize Menu

Inputs Menu

Inputs/Trigger Menu

Table 3--6 lists the parameters for the Save/Recall Measurements menu and the selections available for each.

Table 3- 6: Save/Recall Measurements menu parameters

Option Selections Default setting

Save None C:\TekApplications\tdsddm2\setups\setup1.ini

Recall None C:\TekApplications\tdsddm2\setups\setup1.ini

Default None

There are no parameters for the Minimize function.

There are three Inputs menus: Inputs/Trigger, Inputs Filter, and Inputs General.

Table 3--7 lists the parameters for the Input Channels area and the selections or range of values available for each.

3- 6

Table 3- 7: Input Channels area parameters

Option Selections Default setting

Read Signal Ch 1, Ch 2, Ch 3, Ch 4, Ref 1, Ref 2, Ref 3, Ref 4,

Math1, Math 2, Math 3, Math 4

Read Gate Ch 1, Ch 2, Ch 3, Ch 4 Ch 2

Sector Pulse Ch 1, Ch 2, Ch 3, Ch 4 Ch 3

Index Pulse Ch 1, Ch 2, Ch 3, Ch 4 Ch 4

Ch 1

Table 3--8 lists the parameters for the Trigger area and the selections or range of values available for each.

TDSDDM2 Disk Drive Measurements Application User Manual

Tektronix TDSDDM2 User manual

Specifications and Main Features

Frequently Asked Questions

User Manual

WARRANTY

Table of Contents

List of Figures

List of Tables

General Safety Summary

Preface

Related Documentation and Online Help

Conventions

Contacting Tektronix

Product Description

Compatibility

Requirements and Restrictions

Updates Through the Web Site

Accessories

Installation

Applying a New Label

Installing the Application

Enabling the Application

Connecting to a System Under Test

Configuration

Setting Up the Oscilloscope Trigger

Setting Up the Application Trigger

Hysteresis

Configuring the Input Waveforms

Basic Operations

Application Interface

Using Basic Oscilloscope Functions

Setting Up the Application

Taking Measurements

Analyzing the Results

Saving the Results to a File

Viewing a Data Log File

Saving and Recalling Setups

Exiting the Application

Tutorial

Setting Up the Oscilloscope

Starting the Application

Recalling a Waveform File

Taking a TAA Measurement

Saving the Results to a Data Log File

Viewing a Data Log File

Stopping the Tutorial

ReturningtotheTutorial

Application Examples

Configuring a Measurement

Using Reference Waveforms

Measuring TAA

Measuring PW50

Measuring Asperity

Measuring Overwrite

Measuring Resolution

Measuring Baseline Shift

Measuring NLTS

Measuring SNR

Creating and Viewing T rack Profile Plots

GPIB Program Example

Guidelines

Program Example

Menu Structure

Parameters

Measurements Menu

Inputs Menu