Manual

Manual
LECROY
X-STREAM
OSCILLOSCOPES
O P E R AT O R ’ S M A N U A L
S E P T E M B E R 2006
LeCroy Corporation
700 Chestnut Ridge Road
Chestnut Ridge, NY 10977–6499
Tel: (845) 578 6020, Fax: (845) 578 5985
Internet: www.lecroy.com
© 2006 by LeCroy Corporation. All rights reserved.
LeCroy, ActiveDSO, WaveLink, JitterTrack, WavePro, WaveMaster, WaveSurfer, WaveExpert,
WaveJet, and Waverunner are registered trademarks of LeCroy Corporation. Other product or
brand names are trademarks or requested trademarks of their respective holders. Information in
this publication supersedes all earlier versions. Specifications subject to change without notice.
Manufactured under an ISO 9000
Registered Quality Management System
Visit www.lecroy.com
certificate.
WM-OM-E Rev I
914498-00 Rev A
to
view
the
This electronic product is subject to
disposal and recycling regulations
that vary by country and region.
Many
countries
prohibit
the
disposal
of
waste
electronic
equipment in standard waste
receptacles.
For more information about proper
disposal and recycling of your
LeCroy product, please visit
www.lecroy.com/recycle.
X-Stream Operator’s Manual
INTRODUCTION.................................................................................................17
How to Use On-line Help ............................................................................................. 17
Type Styles ............................................................................................................................. 17
Instrument Help....................................................................................................................... 17
Windows Help.............................................................................................................. 18
Returning a Product for Service or Repair................................................................... 18
Technical Support........................................................................................................ 18
Staying Up-to-Date ...................................................................................................... 18
Windows License Agreement ...................................................................................... 19
End-user License Agreement For LeCroy® X-Stream Software ................................. 19
Virus Protection ........................................................................................................... 25
Warranty ...................................................................................................................... 25
Specifications............................................................................................................... 26
Vertical System ....................................................................................................................... 26
Max Input Voltage .......................................................................................................... 27
Horizontal System................................................................................................................... 27
Acquisition System.................................................................................................................. 28
Acquisition Modes................................................................................................................... 29
Acquisition Processing............................................................................................................ 29
Triggering System................................................................................................................... 29
Basic Triggers ......................................................................................................................... 30
SMART Triggers ..................................................................................................................... 30
SMART Triggers with Exclusion Technology.......................................................................... 30
Automatic Setup...................................................................................................................... 30
Probes..................................................................................................................................... 30
Color Waveform Display ......................................................................................................... 31
Analog Persistence Display .................................................................................................... 31
Zoom Expansion Traces ......................................................................................................... 31
Rapid Signal Processing......................................................................................................... 31
Internal Waveform Memory..................................................................................................... 31
Setup Storage ......................................................................................................................... 31
Interface .................................................................................................................................. 32
Auxiliary Output....................................................................................................................... 32
Auxiliary Input ......................................................................................................................... 32
Math Tools (standard)............................................................................................................. 32
Measure Tools (standard)....................................................................................................... 33
WM-OM-E Rev I
1
Pass/Fail Testing .................................................................................................................... 33
Master Analysis Package (XMAP) .......................................................................................... 34
Jitter and Timing Analysis Package (JTA2) ............................................................................ 34
Disk Drive Measurement Package (DDM2)............................................................................ 34
General ................................................................................................................................... 35
Warranty and Service .................................................................................................. 36
Environmental Characteristics ................................................................................................ 36
Certifications ........................................................................................................................... 36
CE Declaration of Conformity ................................................................................................. 36
Warranty ...................................................................................................................... 38
Windows License Agreement ...................................................................................... 38
End-User License Agreement For LeCroy X-Stream Software ................................... 38
Virus Protection ........................................................................................................... 44
SAFETY ......................................................................................................45
Safety Requirements ................................................................................................... 45
Safety Symbols ....................................................................................................................... 45
Operating Environment ............................................................................................... 46
Cooling ........................................................................................................................ 47
AC Power Source ........................................................................................................ 47
Power and Ground Connections ................................................................................. 48
Standby (Power) Switch and Scope Operational States ............................................. 48
Fuse Replacement ...................................................................................................... 49
Calibration ................................................................................................................... 49
Cleaning ...................................................................................................................... 49
Abnormal Conditions ................................................................................................... 50
BASIC CONTROLS............................................................................................51
Front Panel Controls ................................................................................................... 51
Trigger Knobs: ........................................................................................................................ 52
Trigger Buttons: ...................................................................................................................... 52
Horizontal Knobs:.................................................................................................................... 52
Horizontal Buttons:.................................................................................................................. 52
Vertical Knobs:........................................................................................................................ 52
Channel Buttons: .................................................................................................................... 53
Wavepilot Control Knobs: ...................................................................................................... 53
Wavepilot Control Buttons: .................................................................................................... 53
Measure .................................................................................................................................. 53
2
WM-OM-E Rev I
X-Stream Operator’s Manual
Analysis................................................................................................................................... 53
Special Features Buttons:...................................................................................................... 53
General Control Buttons: ....................................................................................................... 54
STANDBY Lamp: .................................................................................................................... 54
On-screen Toolbars, Icons, and Dialog Boxes ............................................................ 55
Menu Bar Buttons ................................................................................................................... 55
Dialog Boxes................................................................................................................ 57
Alternate Access Methods ........................................................................................... 57
Mouse and Keyboard Operation............................................................................................. 57
Tool Bar Buttons ..................................................................................................................... 57
Trace Descriptors ........................................................................................................ 58
Trace Annotation..................................................................................................................... 59
Screen Layout.............................................................................................................. 60
Menu Bar ................................................................................................................................ 61
Signal Display Grid ................................................................................................................. 61
Dialog Area ............................................................................................................................. 61
INSTALLATION ..................................................................................................64
Hardware ..................................................................................................................... 64
Instrument Rear Panel ............................................................................................................ 64
Software....................................................................................................................... 64
Checking the Scope Status .................................................................................................... 64
Loading Software Upgrades ................................................................................................... 65
Default Settings ........................................................................................................... 65
WaveMaster and WavePro 7000A Series Scopes ................................................................. 65
DDAScopes ................................................................................................................. 66
Adding a New Option................................................................................................... 66
RESTORING SOFTWARE .................................................................................68
Using the Recovery Disk – non-Windows XP Scopes................................................. 68
System Recovery – Windows XP Scopes ................................................................... 68
Recovery Procedure .................................................................................................... 68
Windows Activation................................................................................................................. 72
Restarting the Application ....................................................................................................... 74
Restarting the Operating System............................................................................................ 74
Removable Hard Drive ................................................................................................ 75
External Monitor........................................................................................................... 76
Writable CD Drive option ............................................................................................. 77
WM-OM-E Rev I
3
CONNECTING TO A SIGNAL............................................................................81
ProLink Interface ......................................................................................................... 81
Connecting the Adapters ........................................................................................................ 82
ProBus Interface.......................................................................................................... 82
AP-1M Hi-Z Adapter .................................................................................................... 83
Auxiliary Output Signals .............................................................................................. 83
To Set Up Auxiliary Output ..................................................................................................... 84
SAMPLING MODES...........................................................................................85
To Select a Sampling Mode.................................................................................................... 85
Single-shot sampling mode ......................................................................................... 85
Basic Capture Technique........................................................................................................ 85
Sequence SAMPLING Mode Working With Segments ............................................... 86
To Set Up Sequence Mode..................................................................................................... 87
Sequence Display Modes ....................................................................................................... 88
To Display Individual Segments ............................................................................................. 89
To View Time Stamps............................................................................................................. 89
RIS Sampling Mode -- For Higher Sample Rates........................................................ 90
Roll Mode .................................................................................................................... 91
VERTICAL SETTINGS AND CHANNEL CONTROLS .......................................92
Adjusting Sensitivity and Position................................................................................ 92
To Adjust Sensitivity................................................................................................................ 92
To Adjust the Waveform's Position ......................................................................................... 92
Coupling ...................................................................................................................... 92
Overload Protection ................................................................................................................ 92
To Set Coupling ...................................................................................................................... 92
Probe Attenuation........................................................................................................ 93
To Set Probe Attenuation........................................................................................................ 93
Bandwidth Limit ........................................................................................................... 93
To Set Bandwidth Limiting ...................................................................................................... 93
Linear and (SinX)/X Interpolation ................................................................................ 93
To Set Up Interpolation ........................................................................................................... 93
Inverting Waveforms ............................................................................................................... 94
QuickZoom .................................................................................................................. 94
To Turn On a Zoom ................................................................................................................ 94
Finding Scale............................................................................................................... 94
To Use Find Scale .................................................................................................................. 94
Variable Gain............................................................................................................... 94
4
WM-OM-E Rev I
X-Stream Operator’s Manual
To Enable Variable Gain......................................................................................................... 94
Channel Deskew.......................................................................................................... 94
To Set Up Channel Deskew ................................................................................................... 94
TIMEBASE AND ACQUISITION SYSTEM.........................................................95
Timebase Setup and Control ....................................................................................... 95
Autosetup .................................................................................................................... 95
Dual Channel Acquisition............................................................................................. 95
Combining of Channels........................................................................................................... 95
SDA 11000 DBI Controls ............................................................................................. 96
SMART Memory .......................................................................................................... 96
To Set Up SMART Memory .................................................................................................... 97
TRIGGERING .....................................................................................................98
Trigger Setup Considerations ...................................................................................... 98
Trigger Modes......................................................................................................................... 98
Trigger Types.......................................................................................................................... 98
Determining Trigger Level, Slope, Source, and Coupling ...................................................... 99
Trigger Source ...................................................................................................................... 100
Level...................................................................................................................................... 100
Holdoff by Time or Events..................................................................................................... 101
Simple Triggers.......................................................................................................... 102
Edge Trigger on Simple Signals ........................................................................................... 102
Control Edge Triggering........................................................................................................ 102
To Set Up an Edge Trigger................................................................................................... 103
SMART Triggers ........................................................................................................ 105
Width Trigger ........................................................................................................................ 105
Glitch Trigger ........................................................................................................................ 106
Interval Trigger...................................................................................................................... 108
Qualified Trigger ................................................................................................................... 112
State Trigger ......................................................................................................................... 115
Dropout Trigger..................................................................................................................... 116
Logic Trigger ......................................................................................................................... 117
Serial Trigger ........................................................................................................................ 119
Aux Input Trigger ....................................................................................................... 119
To Set Up Aux Input.............................................................................................................. 119
DISPLAY FORMATS ........................................................................................120
Display Setup............................................................................................................. 120
Sequence Mode Display ....................................................................................................... 120
WM-OM-E Rev I
5
Persistence Setup ..................................................................................................... 121
Saturation Level .................................................................................................................... 121
3-Dimensional Persistence ................................................................................................... 122
Show Last Trace ................................................................................................................... 123
Persistence Time .................................................................................................................. 124
Locking of Traces.................................................................................................................. 124
To Set Up Persistence .............................................................................................. 124
Screen Saver............................................................................................................. 125
Moving Traces from Grid to Grid ............................................................................... 125
To Move a Channel or Math Trace ....................................................................................... 125
Zooming Waveforms ................................................................................................. 126
To Zoom a Single Channel ................................................................................................... 126
To Zoom by Touch-and-Drag................................................................................................ 127
To Zoom Multiple Waveforms Quickly .................................................................................. 128
Multi-Zoom ............................................................................................................................ 128
XY Display ................................................................................................................. 129
To Set Up XY Displays ......................................................................................................... 129
SAVE AND RECALL ........................................................................................131
Saving and Recalling Scope Settings........................................................................ 131
To Save Scope Settings ....................................................................................................... 131
To Recall Scope Settings...................................................................................................... 131
To Recall Default Settings .................................................................................................... 131
Saving Screen Images .............................................................................................. 132
Saving and Recalling Waveforms.............................................................................. 132
Saving Waveforms................................................................................................................ 132
Recalling Waveforms ............................................................................................................ 134
Disk Utilities ............................................................................................................... 134
To Delete a Single File.......................................................................................................... 134
To Delete All Files in a Folder............................................................................................... 135
To Create a Folder................................................................................................................ 135
PRINTING AND FILE MANAGEMENT ............................................................136
Print, Plot, or Copy .................................................................................................... 136
Printing ...................................................................................................................... 136
To Set Up the Printer ............................................................................................................ 136
To Print.................................................................................................................................. 136
Adding Printers and Drivers .................................................................................................. 136
Changing the Default Printer................................................................................................. 137
6
WM-OM-E Rev I
X-Stream Operator’s Manual
Managing Files .......................................................................................................... 137
Hard Disk Partitions .............................................................................................................. 137
100BASE-T ETHERNET CONNECTION..........................................................138
Connecting to a Network ........................................................................................... 138
Communicating over the Network.............................................................................. 138
Windows Setups ................................................................................................................... 138
System Restore .................................................................................................................... 139
TRACK VIEWS .................................................................................................140
Creating and Viewing a Trend ................................................................................... 140
Creating a Track View ............................................................................................... 140
HISTOGRAMS ..................................................................................................142
Creating and Viewing a Histogram ............................................................................ 142
To Set Up a Single Parameter Histogram ............................................................................ 142
To View Thumbnail Histograms............................................................................................ 143
Persistence Histogram.......................................................................................................... 143
Persistence Trace Range ..................................................................................................... 144
Persistence Sigma ................................................................................................................ 144
Histogram Parameters............................................................................................... 145
Histogram Theory of Operation ................................................................................. 158
Scope Process...................................................................................................................... 159
Parameter Buffer................................................................................................................... 160
Capture of Parameter Events ............................................................................................... 160
Histogram Parameters (XMAP and JTA2 Options) ................................................... 161
Histogram Peaks ....................................................................................................... 162
Binning and Measurement Accuracy ......................................................................... 163
WAVEFORM MEASUREMENTS......................................................................164
Measuring with Cursors ............................................................................................. 164
Cursor Measurement Icons .................................................................................................. 164
Cursors Setup............................................................................................................ 164
Quick Display ........................................................................................................................ 164
Full Setup.............................................................................................................................. 165
Overview of Parameters ............................................................................................ 165
To Turn On Parameters ........................................................................................................ 165
Quick Access to Parameter Setup Dialogs........................................................................... 165
Status Symbols ..................................................................................................................... 166
Using X-Stream Browser to Obtain Status Information ........................................................ 167
Statistics .................................................................................................................... 169
WM-OM-E Rev I
7
To Apply a Measure Mode ........................................................................................ 169
Measure Modes......................................................................................................... 169
Standard Vertical Parameters............................................................................................... 169
Standard Horizontal Parameters .......................................................................................... 170
My Measure .......................................................................................................................... 170
Parameter Math (XMath or XMAP option required)................................................... 170
Logarithmic Parameters........................................................................................................ 170
Excluded Parameters............................................................................................................ 171
Parameter Script Parameter Math ........................................................................................ 171
Param Script vs. P Script ...................................................................................................... 172
To Set Up Parameter Math ................................................................................................... 173
To Set Up Parameter Script Math......................................................................................... 173
Measure Gate............................................................................................................ 174
To Set Up Measure Gate ...................................................................................................... 175
Help Markers ............................................................................................................. 176
To Set Up Help Markers ....................................................................................................... 177
To Turn Off Help Markers ..................................................................................................... 178
To Customize a Parameter........................................................................................ 179
From the Measure Dialog ..................................................................................................... 179
From a Vertical Setup Dialog ................................................................................................ 179
From a Math Setup Dialog .................................................................................................... 179
Parameter Calculations ............................................................................................. 180
Parameters and How They Work.......................................................................................... 180
Determining Time Parameters .............................................................................................. 181
Determining Differential Time Measurements ...................................................................... 182
Level and Slope .................................................................................................................... 183
List of Parameters ..................................................................................................... 184
Qualified Parameters................................................................................................. 184
Range Limited Parameters ................................................................................................... 211
Waveform Gated Parameters.................................................................................... 213
To Set Up Waveform Qualifiers ............................................................................................ 213
WAVEFORM MATH .........................................................................................214
Introduction to Math Traces and Functions ............................................................... 214
Math Made Easy ....................................................................................................... 214
To Set Up a Math Function ................................................................................................... 214
Resampling To Deskew ............................................................................................ 215
To Resample......................................................................................................................... 215
8
WM-OM-E Rev I
X-Stream Operator’s Manual
Rescaling and Assigning Units .................................................................................. 216
To Set Up Rescaling ............................................................................................................. 216
Averaging Waveforms ............................................................................................... 216
Summed vs. Continuous Averaging ..................................................................................... 216
To Set Up Continuous Averaging ......................................................................................... 218
To Set Up Summed Averaging ............................................................................................. 218
Enhanced Resolution................................................................................................. 218
How the Instrument Enhances Resolution............................................................................ 218
To Set Up Enhanced Resolution (ERES) .................................................................. 221
Waveform Copy ......................................................................................................... 221
Waveform Sparser..................................................................................................... 221
To Set Up Waveform Sparser............................................................................................... 222
Interpolation ............................................................................................................... 222
To Set Up Interpolation ......................................................................................................... 222
Fast Wave Port .......................................................................................................... 223
Fast Wave Port Setup -- Initial.............................................................................................. 223
Setup -- Case 1..................................................................................................................... 224
Setup -- Case 2..................................................................................................................... 224
Setup -- Case 3..................................................................................................................... 224
Operational Notes ................................................................................................................. 225
Example Applications ................................................................................................ 225
Header Description ............................................................................................................... 229
Data Length Limitations ........................................................................................................ 229
Performance ......................................................................................................................... 230
Choice of Programming Language ....................................................................................... 230
FFT ............................................................................................................................ 230
Why Use FFT?...................................................................................................................... 230
Improving Dynamic Range ........................................................................................ 233
Record Length ........................................................................................................... 233
FFT Algorithms .......................................................................................................... 233
Glossary................................................................................................................................ 235
FFT Setup ............................................................................................................................. 238
ANALYSIS ........................................................................................................240
Pass/Fail Testing ....................................................................................................... 240
Comparing Parameters......................................................................................................... 240
Mask Tests............................................................................................................................ 240
Actions .................................................................................................................................. 241
WM-OM-E Rev I
9
Setting Up Pass/Fail Testing ..................................................................................... 241
Initial Setup ........................................................................................................................... 241
Comparing a Single Parameter............................................................................................. 242
Comparing Dual Parameters ................................................................................................ 243
Mask Testing......................................................................................................................... 244
UTILITIES .........................................................................................................246
Status ........................................................................................................................ 246
To Access Status Dialog....................................................................................................... 246
Remote communication............................................................................................. 246
To Set Up Remote Communication. ..................................................................................... 246
To Configure the Remote Control Assistant Event Log........................................................ 246
Hardcopy ................................................................................................................... 247
Printing .................................................................................................................................. 247
Clipboard............................................................................................................................... 247
File ........................................................................................................................................ 247
E-Mail .................................................................................................................................... 248
Aux Output ................................................................................................................ 248
Date & Time .............................................................................................................. 248
To Set Time and Date Manually ........................................................................................... 248
To Set Time and Date from the Internet ............................................................................... 248
To Set Time and Date from Windows................................................................................... 249
Options ...................................................................................................................... 250
Preferences ............................................................................................................... 250
Audible Feedback ................................................................................................................. 250
Auto-calibration ..................................................................................................................... 250
Offset Control ........................................................................................................................ 250
Delay Control ........................................................................................................................ 250
Trigger Counter..................................................................................................................... 251
Performance Optimization .................................................................................................... 251
E-mail .................................................................................................................................... 251
Acquisition Status ...................................................................................................... 252
Service ...................................................................................................................... 252
Show Windows Desktop............................................................................................ 252
Touch Screen Calibration .......................................................................................... 253
CUSTOMIZATION ............................................................................................254
Customizing Your Instrument .................................................................................... 254
Introduction ........................................................................................................................... 254
10
WM-OM-E Rev I
X-Stream Operator’s Manual
Solutions ............................................................................................................................... 254
Examples .............................................................................................................................. 255
What is Excel? ...................................................................................................................... 260
What is Mathcad? ................................................................................................................. 260
What is MATLAB?................................................................................................................. 260
What is VBS?........................................................................................................................ 260
What can you do with a customized instrument? ................................................................. 262
Number of Samples ................................................................................................... 263
Calling Excel From Your Instrument .......................................................................... 263
Calling Excel Directly from the Instrument............................................................................ 263
How to Select a Math Function Call...................................................................................... 263
How to Select a Parameter Function Call............................................................................. 264
The Excel Control Dialog ...................................................................................................... 264
Entering a File Name ............................................................................................................ 264
Organizing Excel sheets ....................................................................................................... 265
Scale Setting the Vertical Scale........................................................................................... 265
Trace Descriptors.................................................................................................................. 266
Multiple Inputs and Outputs .................................................................................................. 266
Simple Excel Example 2 ....................................................................................................... 269
Exponential Decay Time Constant Excel Parameter (Excel Example 1) ............................. 273
Gated Parameter Using Excel (Excel Example 2)................................................................ 276
How Does this Work? ........................................................................................................... 277
Correlation Excel Waveform Function (Excel Example 3).................................................... 277
Multiple Traces on One Grid (Excel Example 4) .................................................................. 279
Using a Surface Plot (Excel Example 5)............................................................................... 283
Writing VB Scripts...................................................................................................... 284
Types of Scripts in VBS ........................................................................................................ 284
Loading and Saving VBScripts ............................................................................................. 284
The default parameter function script: explanatory notes..................................................... 288
Scripting with VBScript.......................................................................................................... 289
Variable Types ...................................................................................................................... 289
Variable Names .................................................................................................................... 290
General usage ...................................................................................................................... 290
Arithmetic Operators ............................................................................................................. 291
Results of Calculations ......................................................................................................... 291
Order of Calculations ............................................................................................................ 292
VBS Controls ........................................................................................................................ 292
WM-OM-E Rev I
11
IF . . . Then . . . Else . . . End If ............................................................................................. 293
Summary of If . . . . Then . . . . Else ...................................................................................... 295
Select Case........................................................................................................................... 295
Summary of Select Case . . . . End Select............................................................................ 296
Do . . . Loop .......................................................................................................................... 296
While . . . Wend..................................................................................................................... 297
For . . . Next .......................................................................................................................... 297
VBS Keywords and Functions ................................................................................... 299
Other VBS Words ................................................................................................................. 300
Functions............................................................................................................................... 301
Hints and Tips for VBScripting .............................................................................................. 302
Errors .................................................................................................................................... 303
Error Handling....................................................................................................................... 305
Speed of Execution............................................................................................................... 305
Scripting Ideas ...................................................................................................................... 306
Debugging Scripts ..................................................................................................... 307
Horizontal Control Variables...................................................................................... 307
Vertical Control Variables ..................................................................................................... 307
List of Variables Available to Scripts..................................................................................... 308
Communicating with Other Programs from a VBScript ........................................................ 309
Communicating with Excel from a VBScript ......................................................................... 309
Calling MATLAB from the Instrument ........................................................................ 311
Calling MATLAB.................................................................................................................... 311
How to Select a Waveform Function Call ............................................................................. 311
The MATLAB Waveform Control Panel ................................................................................ 312
MATLAB Waveform Function Editor -- Example .................................................................. 312
MATLAB Example Waveform Plot........................................................................................ 315
How to Select a MATLAB Parameter Call ............................................................................ 316
The MATLAB Parameter Control Panel................................................................................ 316
The MATLAB Parameter Editor ............................................................................................ 317
MATLAB Example Parameter Panel .................................................................................... 318
Further Examples of MATLAB Waveform Functions............................................................ 319
Creating your own MATLAB function.................................................................................... 321
CUSTOMDSO...................................................................................................323
Custom DSO ............................................................................................................. 323
Introduction - What is CustomDSO?..................................................................................... 323
Invoking CustomDSO ........................................................................................................... 323
12
WM-OM-E Rev I
X-Stream Operator’s Manual
CustomDSO Basic Mode ...................................................................................................... 324
Editing a CustomDSO Setup File ......................................................................................... 324
Creating a CustomDSO Setup File....................................................................................... 326
CustomDSO PlugIn Mode .................................................................................................... 326
Creating a CustomDSO PlugIn............................................................................................. 326
Properties of the Control and its Objects .............................................................................. 328
Removing a PlugIn................................................................................................................ 331
First Example PlugIn - Exchanging Two Traces on the Grids .............................................. 331
Second Example PlugIn - Log-Log FFT Plot ........................................................................ 334
Control Variables in CustomDSO ......................................................................................... 336
LABNOTEBOOK ..............................................................................................337
Introduction to LabNotebook............................................................................... 337
Preferences.............................................................................................................. 337
Miscellaneous Settings ......................................................................................................... 337
Hardcopy Setup .................................................................................................................... 337
E-mail Setup ......................................................................................................................... 338
Creating a Notebook Entry................................................................................... 338
Recalling Notebook Entries .................................................................................. 341
Creating a Report................................................................................................... 342
Previewing a Report.............................................................................................................. 342
Locating a Notebook Entry ................................................................................................... 342
Creating the Report............................................................................................................... 343
Formatting the Report................................................................................................ 344
Managing Notebook Entry Data................................................................................. 345
Adding Annotations............................................................................................................... 345
Deleting Notebook Entries .................................................................................................... 345
Saving Notebook Entries to a Folder .................................................................................... 345
Managing the Database........................................................................................................ 345
To Start a New Database...................................................................................................... 346
DDA ..................................................................................................................347
DDA Front Panel Controls ......................................................................................... 347
DDA Specifications .................................................................................................... 347
Additional DDA Triggers ....................................................................................................... 347
Disk Drive Measurement Package (DDM2).......................................................................... 347
Automated DDA Measurements ........................................................................................... 348
Advanced DDA Analysis ....................................................................................................... 349
Drive Analysis Overview ............................................................................................ 349
WM-OM-E Rev I
13
Obstacles that Can Be Overcome Using the DDA’s Channel Analysis................................ 349
What Channel Analysis Provides.......................................................................................... 350
Channel Emulation................................................................................................................ 350
With or Without Reference.................................................................................................... 351
Stop On SAM ........................................................................................................................ 352
Analog Compare ................................................................................................................... 352
Measure’s Drive Parameters ................................................................................................ 354
Setting Up Channel Emulation .................................................................................. 354
Drive Analysis Setup............................................................................................................. 354
Channel Setup ...................................................................................................................... 356
Setting Up Analog Compare...................................................................................... 358
Drive Analysis Setup............................................................................................................. 358
Channel Setup ...................................................................................................................... 359
Setting Up Noise Analysis ......................................................................................... 359
Setting Up Disk Triggers ........................................................................................... 361
Read Gate............................................................................................................................. 361
Sector Pulse.......................................................................................................................... 361
Servo Gate ............................................................................................................................ 362
Setting Up Zoom ....................................................................................................... 363
DDA REFERENCE INFORMATION.................................................................364
Channel Analysis Concepts....................................................................................... 364
Using the DDA's Equalization Filter ...................................................................................... 364
Selecting the Waveform Section to Be Analyzed ................................................................. 365
DDA Markers ........................................................................................................................ 367
Setting Up to Use Drive Channel Analysis ................................................................ 367
Which Signals to Provide ...................................................................................................... 367
Choosing the Waveform Section to Be Analyzed ................................................................. 367
Selecting the Reference Waveform ...................................................................................... 368
Time/Div Settings.................................................................................................................. 369
Automatically Shown Traces................................................................................................. 370
Setting Bit Cell Time ............................................................................................................. 370
Retraining the Filter............................................................................................................... 370
Choosing an Analysis Method ................................................................................... 370
Analog Compare ................................................................................................................... 371
Channel Emulation without Reference ................................................................................. 371
Channel Emulation with Reference ...................................................................................... 371
Channel Emulation without Reference ...................................................................... 372
14
WM-OM-E Rev I
X-Stream Operator’s Manual
Notes on Using Channel Emulation without Reference........................................................ 374
Channel Emulation with Reference ........................................................................... 375
Notes on Using Channel Emulation with Reference............................................................. 377
Using Analog Compare.............................................................................................. 378
Notes on Using Head/Analog Compare................................................................................ 379
Local Feature Concepts............................................................................................. 380
Overview ............................................................................................................................... 380
Peak-Trough Identification.................................................................................................... 381
Local Baselines..................................................................................................................... 381
Setting Hysteresis ................................................................................................................. 383
Local Parameters.................................................................................................................. 383
Local Feature Parameters ......................................................................................... 385
Disk Standard Parameters......................................................................................... 400
Disk PRML Parameters ............................................................................................. 408
Noise Parameters ...................................................................................................... 417
PRML Channel Emulation ......................................................................................... 420
Why PRML?.......................................................................................................................... 420
Principle of Equalization........................................................................................................ 421
-3 dB Frequency ................................................................................................................... 422
Boost at fc ............................................................................................................................. 422
Group Delay.......................................................................................................................... 423
Resampling ADC .................................................................................................................. 424
Finite Impulse Response (FIR) ............................................................................................. 424
Phase Locked Loop (PLL) .................................................................................................... 424
Automatic Gain Control (AGC) ............................................................................................. 425
PLL and AGC........................................................................................................................ 426
ML Detector .......................................................................................................................... 426
Viterbi Detector & Trellis ....................................................................................................... 426
SAM ...................................................................................................................................... 426
Encoding ............................................................................................................................... 427
Error Correction .................................................................................................................... 427
User Defined Trellis ................................................................................................... 427
File Format and Language (version 1).................................................................................. 427
Loading Your UDT File Remotely ......................................................................................... 428
Example File ......................................................................................................................... 434
WM-OM-E Rev I
15
BLANK PAGE
16
WM-OM-E Rev I
X-Stream Operator’s Manual
INTRODUCTION
How to Use On-line Help
Type Styles
Activators of pop-up text and images appear as green, underlined, italic: Pop-up. To close pop-up
text and images after opening them, touch the pop-up text again.
Link text appears blue and underlined: Link. Links jump you to other topics, URLs, or images; or to
another location within the same Help window. After making a jump, you can touch the Back
icon in the toolbar at the top of the Help window to return to the Help screen you just left. With each
touch of the Back icon, you return to the preceding Help screen.
Instrument Help
When you press the front panel Help button
(if available), or touch the on-screen Help
, you will be presented with a menu: you can choose either to have information
button
found for you automatically or to search for information yourself.
If you want context-sensitive Help, that is, Help related to what was displayed on the screen when
you requested Help, touch
in the drop-down menu, then touch the on-screen
control (or front panel button or knob) that you need information about. The instrument will
automatically display Help about that control.
If you want information about something not displayed on the screen, touch one of the buttons
inside the drop-down menu to display the on-line Help manual:
Contents displays the Table of Contents.
Index displays an alphabetical listing of keywords.
Search locates every occurrence of the keyword that you enter.
www.LeCroy.com connects you to LeCroy's Web site where you can find
Lab Briefs, Application Notes, and other useful information. This feature
requires that the instrument be connected to the internet through the
Ethernet port on the scope's rear panel. Refer to Remote Communication
for setup instructions.
WM-OM-E Rev I
17
About opens the Utilities "Status" dialog, which shows software version
and other system information.
Once opened, the Help window will display its navigation pane: the part of the window that shows
the Table of Contents and Index. When you touch anywhere outside of the Help window, this
navigation pane will disappear to reveal more of your signal. To make it return, touch the Show
icon at the top of the Help window or touch inside the Help information pane.
Windows Help
In addition to instrument Help, you can also access on-line Help for Microsoft® Windows®. This
help is accessible by minimizing the scope application, then touching the Start button in the
Windows task bar at the bottom of the screen and selecting Help.
Returning a Product for Service or Repair
If you need to return a LeCroy product, identify it by its model and serial numbers. Describe the
defect or failure, and give us your name and telephone number.
For factory returns, use a Return Authorization Number (RAN), which you can get from customer
service. Write the number clearly on the outside of the shipping carton.
Return products requiring only maintenance to your local customer service center.
If you need to return your scope for any reason, use the original shipping carton. If this is not
possible, be sure to use a rigid carton. The scope should be packed so that it is surrounded by a
minimum of four inches (10 cm) of shock absorbent material.
Within the warranty period, transportation charges to the factory will be your responsibility.
Products under warranty will be returned to you with transport prepaid by LeCroy. Outside the
warranty period, you will have to provide us with a purchase order number before the work can be
done. You will be billed for parts and labor related to the repair work, as well as for shipping.
You should prepay return shipments. LeCroy cannot accept COD (Cash On Delivery) or Collect
Return shipments. We recommend using air freight.
Technical Support
You can get assistance with installation, calibration, and a full range of software applications from
your customer service center. Visit the LeCroy Web site at http://www.lecroy.com for the center
nearest you.
Staying Up-to-Date
To maintain your instrument’s performance within specifications, have us calibrate it at least once a
year. LeCroy offers state-of-the-art performance by continually refining and improving the
instrument’s capabilities and operation. We frequently update both firmware and software during
service, free of charge during warranty.
You can also install new purchased software options in your scope yourself, without having to
18
WM-OM-E Rev I
X-Stream Operator’s Manual
return it to the factory. Simply provide us with your instrument serial number and ID, and the version
number of instrument software installed. We will provide you with a unique option key that consists
of a code to be entered through the Utilities' Options dialog to load the software option.
Windows License Agreement
LeCroy's agreement with Microsoft prohibits users from running software on LeCroy X-Stream
oscilloscopes that is not relevant to measuring, analyzing, or documenting waveforms.
End-user License Agreement For LeCroy® X-Stream Software
IMPORTANT-READ CAREFULLY: THIS END-USER LICENSE AGREEMENT (“EULA”) IS A
LEGAL AGREEMENT BETWEEN THE INDIVIDUAL OR ENTITY LICENSING THE SOFTWARE
PRODUCT (“YOU” OR “YOUR”) AND LECROY CORPORATION (“LECROY”) FOR THE
SOFTWARE PRODUCT(S) ACCOMPANYING THIS EULA, WHICH INCLUDE(S): COMPUTER
PROGRAMS; ANY “ONLINE” OR ELECTRONIC DOCUMENTATION AND PRINTED
MATERIALS PROVIDED BY LECROY HEREWITH (“DOCUMENTATION”); ASSOCIATED
MEDIA; AND ANY UPDATES (AS DEFINED BELOW) (COLLECTIVELY, THE “SOFTWARE
PRODUCT”). BY USING AN INSTRUMENT TOGETHER WITH OR CONTAINING THE
SOFTWARE PRODUCT, OR BY INSTALLING, COPYING, OR OTHERWISE USING THE
SOFTWARE PRODUCT, IN WHOLE OR IN PART, YOU AGREE TO BE BOUND BY THE
TERMS OF THIS EULA. IF YOU DO NOT AGREE TO THE TERMS OF THIS EULA, DO NOT
INSTALL, COPY, OR OTHERWISE USE THE SOFTWARE PRODUCT; YOU MAY RETURN
THE SOFTWARE PRODUCT TO YOUR PLACE OF PURCHASE FOR A FULL REFUND. IN
ADDITION, BY INSTALLING, COPYING, OR OTHERWISE USING ANY MODIFICATIONS,
ENHANCEMENTS, NEW VERSIONS, BUG FIXES, OR OTHER COMPONENTS OF THE
SOFTWARE PRODUCT THAT LECROY PROVIDES TO YOU SEPARATELY AS PART OF THE
SOFTWARE PRODUCT (“UPDATES”), YOU AGREE TO BE BOUND BY ANY ADDITIONAL
LICENSE TERMS THAT ACCOMPANY SUCH UPDATES. IF YOU DO NOT AGREE TO SUCH
ADDITIONAL LICENSE TERMS, YOU MAY NOT INSTALL, COPY, OR OTHERWISE USE
SUCH UPDATES.
THE PARTIES CONFIRM THAT THIS AGREEMENT AND ALL RELATED DOCUMENTATION
ARE AND WILL BE DRAFTED IN ENGLISH. LES PARTIES AUX PRÉSENTÉS CONFIRMENT
LEUR VOLONTÉ QUE CETTE CONVENTION DE MÊME QUE TOUS LES DOCUMENTS Y
COMPRIS TOUT AVIS QUI S’Y RATTACHÉ, SOIENT REDIGÉS EN LANGUE ANGLAISE.
1. GRANT OF LICENSE.
1.1 License Grant. Subject to the terms and conditions of this EULA and payment of all applicable
fees, LeCroy grants to you a nonexclusive, nontransferable license (the “License”) to: (a) operate
the Software Product as provided or installed, in object code form, for your own internal business
purposes, (i) for use in or with an instrument provided or manufactured by LeCroy (an “Instrument”),
(ii) for testing your software product(s) (to be used solely by you) that are designed to operate in
conjunction with an Instrument (“Your Software”), and (iii) make one copy for archival and back-up
purposes; (b) make and use copies of the Documentation; provided that such copies will be used
only in connection with your licensed use of the Software Product, and such copies may not be
republished or distributed (either in hard copy or electronic form) to any third party; and (c) copy,
modify, enhance and prepare derivative works (“Derivatives”) of the source code version of those
portions of the Software Product set forth in and identified in the Documentation as “Samples”
WM-OM-E Rev I
19
(“Sample Code”) for the sole purposes of designing, developing, and testing Your Software. If you
are an entity, only one designated individual within your organization, as designated by you, may
exercise the License; provided that additional individuals within your organization may assist with
respect to reproducing and distributing Sample Code as permitted under Section 1.1(c)(ii). LeCroy
reserves all rights not expressly granted to you. No license is granted hereunder for any use other
than that specified herein, and no license is granted for any use in combination or in connection
with other products or services (other than Instruments and Your Software) without the express
prior written consent of LeCroy. The Software Product is licensed as a single product. Its
component parts may not be separated for use by more than one user. This EULA does not grant
you any rights in connection with any trademarks or service marks of LeCroy. The Software
Product is protected by copyright laws and international copyright treaties, as well as other
intellectual property laws and treaties. The Software Product is licensed, not sold. The terms of this
printed, paper EULA supersede the terms of any on-screen license agreement found within the
Software Product.
1.2 Upgrades. If the Software Product is labeled as an “upgrade,” (or other similar designation) the
License will not take effect, and you will have no right to use or access the Software Product unless
you are properly licensed to use a product identified by LeCroy as being eligible for the upgrade
(“Underlying Product”). A Software Product labeled as an “upgrade” replaces and/or supplements
the Underlying Product. You may use the resulting upgraded product only in accordance with the
terms of this EULA. If the Software Product is an upgrade of a component of a package of software
programs that you licensed as a single product, the Software Product may be used and transferred
only as part of that single product package and may not be separated for use on more than one
computer.
1.3. Limitations. Except as specifically permitted in this EULA, you will not directly or indirectly (a)
use any Confidential Information to create any software or documentation that is similar to any of
the Software Product or Documentation; (b) encumber, transfer, rent, lease, time-share or use the
Software Product in any service bureau arrangement; (c) copy (except for archival purposes),
distribute, manufacture, adapt, create derivative works of, translate, localize, port or otherwise
modify the Software Product or the Documentation; (d) permit access to the Software Product by
any party developing, marketing or planning to develop or market any product having functionality
similar to or competitive with the Software Product; (e) publish benchmark results relating to the
Software Product, nor disclose Software Product features, errors or bugs to third parties; or (f)
permit any third party to engage in any of the acts proscribed in clauses (a) through (e). In
jurisdictions in which transfer is permitted, notwithstanding the foregoing prohibition, transfers will
only be effective if you transfer a copy of this EULA, as well as all copies of the Software Product,
whereupon your right to use the Software product will terminate. Except as described in this
Section 1.3, You are not permitted (i) to decompile, disassemble, reverse compile, reverse
assemble, reverse translate or otherwise reverse engineer the Software Product, (ii) to use any
similar means to discover the source code of the Software Product or to discover the trade secrets
in the Software Product, or (iii) to otherwise circumvent any technological measure that controls
access to the Software Product. You may reverse engineer or otherwise circumvent the
technological measures protecting the Software Product for the sole purpose of identifying and
analyzing those elements that are necessary to achieve Interoperability (the “Permitted Objective”)
only if: (A) doing so is necessary to achieve the Permitted Objective and it does not constitute
infringement under Title 17 of the United States Code; (B) such circumvention is confined to those
parts of the Software Product and to such acts as are necessary to achieve the Permitted
20
WM-OM-E Rev I
X-Stream Operator’s Manual
Objective; (C) the information to be gained thereby has not already been made readily available to
you or has not been provided by LeCroy within a reasonable time after a written request by you to
LeCroy to provide such information; (D) the information gained is not used for any purpose other
than the Permitted Objective and is not disclosed to any other person except as may be necessary
to achieve the Permitted Objective; and (E) the information obtained is not used (1) to create a
computer program substantially similar in its expression to the Software Product including, but not
limited to, expressions of the Software Product in other computer languages, or (2) for any other act
restricted by LeCroy’s intellectual property rights in the Software Product. “Interoperability” will
have the same meaning in this EULA as defined in the Digital Millennium Copyright Act, 17 U.S.C.
§1201(f), the ability of computer programs to exchange information and of such programs mutually
to use the information which has been exchanged.
1.4 PRERELEASE CODE. Portions of the Software Product may be identified as prerelease code
(“Prerelease Code”). Prerelease Code is not at the level of performance and compatibility of the
final, generally available product offering. The Prerelease Code may not operate correctly and may
be substantially modified prior to first commercial shipment. LeCroy is not obligated to make this or
any later version of the Prerelease Code commercially available. The License with respect to the
Prerelease Code terminates upon availability of a commercial release of the Prerelease Code from
LeCroy.
2. SUPPORT SERVICES.
At LeCroy’s sole discretion, from time to time, LeCroy may provide Updates to the Software
Product. LeCroy shall have no obligation to revise or update the Software Product or to support
any version of the Software Product. At LeCroy’s sole discretion, upon your request, LeCroy may
provide you with support services related to the Software Product (“Support Services”) pursuant to
the LeCroy policies and programs described in the Documentation or otherwise then in effect, and
such Support Services will be subject to LeCroy’s then-current fees therefor, if any. Any Update or
other supplemental software code provided to you pursuant to the Support Services will be
considered part of the Software Product and will be subject to the terms and conditions of this
EULA. LeCroy may use any technical information you provide to LeCroy during LeCroy’s provision
of Support Services, for LeCroy’s business purposes, including for product support and
development. LeCroy will not utilize such technical information in a form that personally identifies
you.
3. PROPRIETARY RIGHTS.
3.1 Right and Title. All right, title and interest in and to the Software Product and Documentation
(including but not limited to any intellectual property or other proprietary rights, images, icons,
photographs, text, and “applets” embodied in or incorporated into the Software Product, collectively,
“Content”), and all Derivatives, and any copies thereof are owned by LeCroy and/or its licensors or
third-party suppliers, and is protected by applicable copyright or other intellectual property laws and
treaties. You will not take any action inconsistent with such title and ownership. This EULA grants
you no rights to use such Content outside of the proper exercise of the license granted hereunder,
and LeCroy will not be responsible or liable therefor.
3.2 Intellectual Property Protection. You may not alter or remove any printed or on-screen
copyright, trade secret, proprietary or other legal notices contained on or in copies of the Software
Product or Documentation.
WM-OM-E Rev I
21
3.3 Confidentiality. Except for the specific rights granted by this EULA, neither party shall use or
disclose any Confidential Information (as defined below) of the other party without the written
consent of the disclosing party. A party receiving Confidential Information from the other shall use
the highest commercially reasonable degree of care to protect the Confidential Information,
including ensuring that its employees and consultants with access to such Confidential Information
have agreed in writing not to disclose the Confidential Information. You shall bear the responsibility
for any breaches of confidentiality by your employees and consultants. Within ten (10) days after
request of the disclosing party, and in the disclosing party's sole discretion, the receiving party shall
either return to the disclosing party originals and copies of any Confidential Information and all
information, records and materials developed therefrom by the receiving party, or destroy the same,
other than such Confidential Information as to which this EULA expressly provides a continuing
right to the receiving party to retain at the time of the request. Either party may only disclose the
general nature, but not the specific financial terms, of this EULA without the prior consent of the
other party; provided either party may provide a copy of this EULA to any finance provider in
conjunction with a financing transaction, if such provider agrees to keep this EULA confidential.
Nothing herein shall prevent a receiving party from disclosing all or part of the Confidential
Information as necessary pursuant to the lawful requirement of a governmental agency or when
disclosure is required by operation of law; provided that prior to any such disclosure, the receiving
party shall use reasonable efforts to (a) promptly notify the disclosing party in writing of such
requirement to disclose, and (b) cooperate fully with the disclosing party in protecting against any
such disclosure or obtaining a protective order. Money damages will not be an adequate remedy if
this Section 4.3 is breached and, therefore, either party shall, in addition to any other legal or
equitable remedies, be entitled to seek an injunction or similar equitable relief against such breach
or threatened breach without the necessity of posting any bond. As used herein, “Confidential
Information” means LeCroy pricing or information concerning new LeCroy products, trade secrets
(including without limitation all internal header information contained in or created by the Software
Product, all benchmark and performance test results and all Documentation) and other proprietary
information of LeCroy; and any business, marketing or technical information disclosed by LeCroy,
or its representatives, or you in relation to this EULA, and either (i) disclosed in writing and marked
as confidential at the time of disclosure or (ii) disclosed in any other manner such that a reasonable
person would understand the nature and confidentiality of the information. Confidential Information
does not include information (A) already in the possession of the receiving party without an
obligation of confidentiality to the disclosing party, (B) hereafter rightfully furnished to the receiving
party by a third party without a breach of any separate nondisclosure obligation to the disclosing
party, (C) publicly known without breach of this EULA, (d) furnished by the disclosing party to a third
party without restriction on subsequent disclosure, or (e) independently developed by the receiving
party without reference to or reliance on the Confidential Information.
4. TERMINATION.
This EULA will remain in force until termination pursuant to the terms hereof. You may terminate
this EULA at any time. This EULA will also terminate if you breach any of the terms or conditions of
this EULA. You agree that if this EULA terminates for any reason, the License will immediately
terminate and you will destroy all copies of the Software Product (and all Derivatives), installed or
otherwise, the Documentation, and the Confidential Information (and all derivatives of any of the
foregoing) that are in your possession or under your control. The provisions of Sections 1.3, 4, 6, 7,
8, and 9 will survive any termination or expiration hereof.
22
WM-OM-E Rev I
X-Stream Operator’s Manual
5. U.S. GOVERNMENT RESTRICTED RIGHTS.
If any Software Product or Documentation is acquired by or on behalf of a unit or agency of the
United States Government (any such unit or agency, the “Government”), the Government agrees
that the Software Product or Documentation is “commercial computer software” or “commercial
computer software documentation” and that, absent a written agreement to the contrary, the
Government’s rights with respect to the Software Product or Documentation are, in the case of
civilian agency use, Restricted Rights, as defined in FAR §52.227.19, and if for Department of
Defense use, limited by the terms of this EULA, pursuant to DFARS §227.7202. The use of the
Software Product or Documentation by the Government constitutes acknowledgment of LeCroy’s
proprietary rights in the Software Product and Documentation. Manufacturer is LeCroy Corporation,
700 Chestnut Ridge Road, Chestnut Ridge, NY 10977 USA.
6. EXPORT RESTRICTIONS.
You agree that you will not export or re-export the Software Product, any part thereof, or any
process or service that is the direct product of the Software Product (the foregoing collectively
referred to as the “Restricted Components”), to any country, person, entity or end user subject to
U.S. export restrictions. You specifically agree not to export or re-export any of the Restricted
Components (a) to any country to which the U.S. has embargoed or restricted the export of goods
or services, which currently include, but are not necessarily limited to Cuba, Iran, Iraq, Libya, North
Korea, Sudan and Syria, or to any national of any such country, wherever located, who intends to
transmit or transport the Restricted Components back to such country; (b) to any end user who you
know or have reason to know will utilize the Restricted Components in the design, development or
production of nuclear, chemical or biological weapons; or (c) to any end-user who has been
prohibited from participating in U.S. export transactions by any federal agency of the U.S.
government. You warrant and represent that neither the BXA nor any other U.S. federal agency has
suspended, revoked or denied your export privileges. It is your responsibility to comply with the
latest United States export regulations, and you will defend and indemnify LeCroy from and against
any damages, fines, penalties, assessments, liabilities, costs and expenses (including reasonable
attorneys' fees and court costs) arising out of any claim that the Software Product, Documentation,
or other information or materials provided by LeCroy hereunder were exported or otherwise
accessed, shipped or transported in violation of applicable laws and regulations.
7. RISK ALLOCATION.
7.1 No Warranty. THE SOFTWARE PRODUCT IS NOT ERROR-FREE AND THE SOFTWARE
PRODUCT AND SUPPORT SERVICES IS/ARE BEING PROVIDED "AS IS" WITHOUT
WARRANTY OF ANY KIND. LECROY, FOR ITSELF AND ITS SUPPLIERS, HEREBY
DISCLAIMS ALL WARRANTIES, WHETHER EXPRESS OR IMPLIED, ORAL OR WRITTEN,
WITH RESPECT TO THE SOFTWARE PRODUCT OR ANY SUPPORT SERVICES INCLUDING,
WITHOUT LIMITATION, ALL IMPLIED WARRANTIES OF TITLE OR NON-INFRINGEMENT,
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, ACCURACY, INTEGRATION,
VALIDITY, EXCLUSIVITY, MERCHANTABILITY, NON-INTERFERENCE WITH ENJOYMENT,
FITNESS FOR ANY PARTICULAR PURPOSE, AND ALL WARRANTIES IMPLIED FROM ANY
COURSE OF DEALING OR USAGE OF TRADE. YOU ACKNOWLEDGE THAT NO
WARRANTIES HAVE BEEN MADE TO YOU BY OR ON BEHALF OF LECROY OR OTHERWISE
FORM THE BASIS FOR THE BARGAIN BETWEEN THE PARTIES.
7.2. Limitation of Liability. LECROY’S LIABILITY FOR DAMAGES FOR ANY CAUSE
WM-OM-E Rev I
23
WHATSOEVER, REGARDLESS OF THE FORM OF ANY CLAIM OR ACTION, SHALL NOT
EXCEED THE GREATER OF THE AMOUNT ACTUALLY PAID BY YOU FOR THE SOFTWARE
PRODUCT OR U.S.$5.00; PROVIDED THAT IF YOU HAVE ENTERED INTO A SUPPORT
SERVICES AGREEMENT WITH LECROY, LECROY’S ENTIRE LIABILITY REGARDING
SUPPORT SERVICES WILL BE GOVERNED BY THE TERMS OF THAT AGREEMENT.
LECROY SHALL NOT BE LIABLE FOR ANY LOSS OF PROFITS, LOSS OF USE, LOSS OF
DATA, INTERRUPTION OF BUSINESS, NOR FOR INDIRECT, SPECIAL, INCIDENTAL,
CONSEQUENTIAL OR EXEMPLARY DAMAGES OF ANY KIND, WHETHER UNDER THIS EULA
OR OTHERWISE ARISING IN ANY WAY IN CONNECTION WITH THE SOFTWARE PRODUCT,
THE DOCUMENTATION OR THIS EULA. SOME JURISDICTIONS DO NOT ALLOW THE
EXCLUSION OR LIMITATION OF INCIDENTAL OR CONSEQUENTIAL DAMAGES, SO THE
ABOVE EXCLUSION OR LIMITATION MAY NOT APPLY TO YOU. THESE LIMITATIONS ARE
INDEPENDENT FROM ALL OTHER PROVISIONS OF THIS EULA AND SHALL APPLY
NOTWITHSTANDING THE FAILURE OF ANY REMEDY PROVIDED HEREIN.
7.3 Indemnification. You will defend, indemnify and hold harmless LeCroy and its officers, directors,
affiliates, contractors, agents, and employees from, against and in respect of any and all
assessments, damages, deficiencies, judgments, losses, obligations and liabilities (including costs
of collection and reasonable attorneys’ fees, expert witness fees and expenses) imposed upon or
suffered or incurred by them arising from or related to your use of the Software Product.
8. GENERAL PROVISIONS.
8.1 Compliance with Laws. You will comply with all laws, legislation, rules, regulations, and
governmental requirements with respect to the Software Product, and the performance by you of
your obligations hereunder, of any jurisdiction in or from which you directly or indirectly cause the
Software Product to be used or accessed.
8.2 No Agency. Nothing contained in this EULA will be deemed to constitute either party as the
agent or representative of the other party, or both parties as joint venturers or partners for any
purpose.
8.3 Entire Agreement; Waiver; Severability. This EULA constitutes the entire agreement between
the parties with regard to the subject matter hereof. No provision of, right, power or privilege under
this EULA will be deemed to have been waived by any act, delay, omission or acquiescence by
LeCroy, its agents, or employees, but only by an instrument in writing signed by an authorized
officer of LeCroy. No waiver by LeCroy of any breach or default of any provision of this EULA by
you will be effective as to any other breach or default, whether of the same or any other provision
and whether occurring prior to, concurrent with, or subsequent to the date of such waiver. If any
provision of this EULA is declared by a court of competent jurisdiction to be invalid, illegal or
unenforceable, such provision will be severed from this EULA and all the other provisions will
remain in full force and effect.
8.4 Governing Law; Jurisdiction; Venue. This EULA will be governed by and construed in
accordance with the laws of the State of New York, USA, without regard to its choice of law
provisions. The United Nations Convention on Contracts for the International Sale of Goods will not
apply to this EULA. Exclusive jurisdiction and venue for any litigation arising under this EULA is in
the federal and state courts located in New York, New York, USA and both parties hereby consent
to such jurisdiction and venue for this purpose.
24
WM-OM-E Rev I
X-Stream Operator’s Manual
8.5 Assignment. This EULA and the rights and obligations hereunder, may not be assigned, in
whole or in part by you, except to a successor to the whole of your business, without the prior
written consent of LeCroy. In the case of any permitted assignment or transfer of or under this
EULA, this EULA or the relevant provisions will be binding upon, and inure to the benefit of, the
successors, executors, heirs, representatives, administrators and assigns of the parties hereto.
8.6 Notices. All notices or other communications between LeCroy and you under this EULA will be
in writing and delivered personally, sent by confirmed fax, by confirmed e-mail, by certified mail,
postage prepaid and return receipt requested, or by a nationally recognized express delivery
service. All notices will be in English and will be effective upon receipt.
8.7 Headings. The headings used in this EULA are intended for convenience only and will not be
deemed to supersede or modify any provisions.
8.8 Acknowledgment. Licensee acknowledges that (a) it has read and understands this EULA, (b)
it has had an opportunity to have its legal counsel review this EULA, (c) this EULA has the same
force and effect as a signed agreement, and (d) issuance of this EULA does not constitute general
publication of the Software Product or other Confidential Information.
Virus Protection
Because your scope runs on a Windows-based PC platform, it must be protected from viruses, as
with any PC on a corporate network. It is crucial that the scope be kept up to date with Windows
Critical Updates, and that anti-virus software be installed and continually updated.
Visit http://www.lecroy.com/dsosecurity for more information regarding Windows Service Pack
compatibility with LeCroy operating software, and related matters.
Warranty
The instrument is warranted for normal use and operation, within specifications, for a period of one
year from shipment. LeCroy will either repair or, at our option, replace any product returned to one
of our authorized service centers within this period. However, in order to do this we must first
examine the product and find that it is defective due to workmanship or materials and not due to
misuse, neglect, accident, or abnormal conditions or operation.
LeCroy shall not be responsible for any defect, damage, or failure caused by any of the following: a)
attempted repairs or installations by personnel other than LeCroy representatives, or b) improper
connection to incompatible equipment or c) for any damage or malfunction caused by the use of
non-LeCroy supplies. Furthermore, LeCroy shall not be obligated to service a product that has
been modified or integrated where the modification or integration increases the task duration or
difficulty of servicing the oscilloscope. Spare and replacement parts, and repairs, all have a 90-day
warranty.
The oscilloscope’s firmware has been thoroughly tested and is presumed to be functional.
Nevertheless, it is supplied without warranty of any kind covering detailed performance. Products
not made by LeCroy are covered solely by the warranty of the original equipment manufacturer.
WM-OM-E Rev I
25
Specifications
Note: Specifications are subject to change without notice.
Vertical System
Bandwidth (-3 dB @ 50 ohms):*
WaveMaster 8600A & 8620A†
6 GHz @ 50 ohms (at sample speed 20 GS/s)
WaveMaster 8500A‡
5 GHz
DDA-5005A
4 GHz
WaveMaster 8400A, 8420
DDA-3000A
3 GHz
5 mV/div to 1 V/div
2 mV/div to 4.99 mV/div
1 GHz
500 MHz
WavePro 7200A
10 mV/div to 1 V/div
5 mV/div to 9.95 mV/div
2 mV/div to 4.99 mV/div
2 GHz
1 GHz
500 MHz
WavePro 7300A
10 mV/div to 1 V/div
5 mV to 9.95 V/div
2 mV/div to 4.99 mV/div
3 GHz
1 GHz
500 MHz
WavePro 7100A
* At max. channel sampling rate
†
Derates 50 MHz/ºC @ T>30 ºC
‡
Derates 20 MHz/ºC @ T>30 ºC
Input Channels: 4
Rise Time (typical):
WaveMaster 8600A & 8620A 75 ps (at sample speed >/= 20 GS/s)
WaveMaster 8500A
DDA-5005A
26
90 ps
WaveMaster 8400A, 8420
115 ps
DDA-3000A
150 ps
WavePro 7100A
400 ps
WavePro 7200A
225 ps
WavePro 7300A
150 ps
WM-OM-E Rev I
X-Stream Operator’s Manual
Bandwidth Limiters:
•
•
•
•
•
•
Full
4 GHz (WaveMaster 8600A, 8500A, DDA-5005A)
3 GHz (WaveMaster 8600A, 8500A, 8400A, 8420, DDA-5005A)
1 GHz (WaveMaster scopes, DDA-5005A)
200 MHz
20 MHz
Input Impedance: 50 ohms +/-2%; WavePro 7000A Series: 50 ohms +/-1.5%, 1 Mohms
Input Coupling: DC, GND; AC (WavePro 7000A Series)
Max Input Voltage
WaveMaster, DDA-5005A: +/-4 V peak; WavePro 7000A Series, DDA-3000A: 50 ohms: 5 Vrms, 1
Mohms: 100 Vmax (peak AC: 5 kHz + DC)
Installation (Overvoltage) Category: CAT I
Vertical Resolution: 8 bits; up to 11 bits with enhanced resolution (ERES)
Sensitivity: 2 mV to 1 V/div fully variable (WavePro 7000A Series: 1 Mohms: 2 mV to 2 V/div fully
variable)
DC Gain Accuracy: +/-1.5% of full scale
Offset Range: 2 mV to 194 mV/div: +/-750 mV; 195 mV to 1 V/div: +/-4 V (WaveMaster,
DDA-5005A)
DDA-3000A, WavePro 7000A Series:
+/-700 mV @ 2.0 to 4.99 mV/div
50 ohms
+/-1.5 V @ 5 to 100 mV/div
+/-10 V @ 0.102 to 1 V/div
+/-700 mV @ 2.0 to 4.99 mV/div
1 Mohms
+/-1.5 V @ 5 to 100 mV/div
+/-20 V @ 0.102 to 2 V/div
Offset Accuracy: +/-(1.5% of full scale value + 1.5% of offset value + 2 mV); WavePro 7000A
Series, DDA-3000A: +/-(1.5% of full scale value + 0.5% of offset value + 2 mV)
Horizontal System
Timebases: Internal timebase common to 4 input channels; an external clock can be applied at the
auxiliary input
Time/div Range: 20 ps/div to 1000 s/div (10 s/div in Auto trigger mode)
Math & Zoom Traces: 4 independent zoom and 4 math/zoom traces standard; 8 math/zoom
traces available with XMAP (Master Analysis Package) option
WM-OM-E Rev I
27
Clock Accuracy: </= 1 ppm at 0 to 50 °C (WavePro 7000A Series, DDA-3000A: </= 10 ppm at 0 to
40 °C)
Interpolator Resolution: 1.2 ps
External Timebase Clock: 100 MHz, 50 ohms impedance, applied at the rear input (10 MHz, 50
ohms for WavePro 7000A Series)
External Sample Clock: 30 MHz to 2 GHz max., 50 ohms impedance, applied at the Auxiliary
input (WavePro 7100A, DDA-3000A: 30 MHz to 1 GHz)
Acquisition System
Single-shot Sample Rate/Ch: 10 GS/s (WaveMaster 8620A: 20 GS/s)
Memory:
WaveMaster 8420A and 8620A:
Maximum Acquisition
Points/Ch
Standard
10M
VL Memory Option
32M
XL Memory Option
50M
WaveMaster 8400A XXL and 8600A XXL: 50 Mpts/Ch; 100 Mpts when using 4 or 2 Ch,
respectively
WavePro 7100A, 7200A, 7300A:
Maximum Acquisition
Points/Ch
4 Ch/2 Ch
Standard
10M/20M
VL Memory Option
16M/32M
XL Memory Option
24M/50M
WavePro 7100A, 7200A, 7300A XXL models: 50 Mpts/Ch; 100 Mpts when using 4 or 2 Ch,
respectively
28
WM-OM-E Rev I
X-Stream Operator’s Manual
Disk Drive Analyzers:
Maximum Acquisition
Points/Ch
4 Ch/2 Ch
DDA 3000
50 Mpts/100 Mpts
DDA 5005A
24 Mpts/50 Mpts
DDA 5005A XXL
50 Mpts/100 Mpts
Acquisition Modes
Single-shot: For transient and repetitive signals: 20 ps/div to 10 s/div
Sequence: 2 to 20,000 segments (number of segments depends upon memory option)
Number of Segments
Standard
500
VL Memory Option
10,000
XL Memory Option
20,000
XXL Memory Option
25,000
Intersegment Time: typically 5 µs (WavePro 7000A Series, DDA-3000A: 6 µs)
Acquisition Processing
Averaging: Summed averaging to 1 million sweeps; Continuous averaging to 1 million sweeps
Enhanced Resolution (ERES): from 8.5 to 11 bits vertical resolution
Envelope (Extrema): Envelope, floor, roof for up to 1 million sweeps
Triggering System
Modes: Normal, Auto, Single, and Stop
Sources: Any input channel, External, ExtX10, Ext/10 or line; slope and level are unique to each
source (except line)
Coupling Mode: DC; WavePro 7000A Series: GND, DC 50 ohms, DC 1 Mohms, AC 1 Mohms
Pre-trigger Delay: 0 to 100% of horizontal time scale
Post-trigger Delay: 0 to 10,000 divisions
Holdoff by Time or Events: Up to 20 s or from 1 to 99,999,999 events
Internal Trigger Range: +/-5 div from center
Maximum Trigger Frequency:
WM-OM-E Rev I
29
WM 8600A
WM 8500/8500A
DDA-5005/DDA-5005A
5 GHz with Edge Trigger, 750 MHz with SMART Trigger
5 GHz with Edge Trigger, 750 MHz with SMART Trigger
WM 8400A/8420
4 GHz with Edge Trigger, 750 MHz with SMART Trigger
DDA-3000A
3 GHz with Edge Trigger, 750 MHz with SMART Trigger
WP 7300A
3 GHz w/Edge Trigger, 750 MHz with SMART Trigger
WP 7200A
2 GHz w/Edge Trigger, 750 MHz with SMART Trigger
WP 7100A
1 GHz w/Edge Trigger, 750 MHz with SMART Trigger
Trigger Jitter: 2.5 ps rms (typical)
Basic Triggers
Edge/Slope/Line: Triggers when the signal meets the slope and level condition.
SMART Triggers
State or Edge qualified: Triggers on any input source only if a defined state or edge occurred on
another input source. Delay between sources is selectable by time or events.
Dropout: Triggers if the input signal drops out for longer than a selectable time-out between 2 ns
and 20 s.
Pattern: Logic combination (AND, NAND, OR, NOR) of 5 inputs (4 channels and external trigger
input). Each source can be high, low, or don't care. The High and Low level can be selected
independently. Triggers at start or end of pattern.
SMART Triggers with Exclusion Technology
Glitch: Triggers on positive or negative glitches with widths selectable from 600 ps to 20 s or on
intermittent faults.
Signal or Pattern Width: Triggers on positive or negative pulse widths selectable from 600 ps to
20 s or on intermittent faults.
Signal or Pattern Interval: Triggers on intervals selectable from 2 ns to 20 s.
Automatic Setup
Autosetup: Automatically sets timebase, trigger, and sensitivity to display a wide range of
repetitive signals.
Vertical Find Scale: Automatically sets the vertical sensitivity and offset for the selected channels
to display a waveform with maximum dynamic range.
Probes
Probes: A variety of optional passive and active probes is available.
Probe System ProLink with ProBus: Automatically detects and supports a wide variety of
30
WM-OM-E Rev I
X-Stream Operator’s Manual
compatible probes; supports ProLink-SMA and ProLink-BNC adapters (ProLink is not available for
WavePro 7000A series)
Scale Factors: Automatically or manually selected depending on probe used
AP-1M Hi-Z Adapter: (not available for WavePro 7000A series) Bandwidth: 500 MHz; full-scale
range: +/-8 V; input protection: +/-150 V
Color Waveform Display
Type: Color 10.4-inch flat panel TFT LCD with high resolution touch screen
Resolution: SVGA; 800 x 600 pixels
Real Time Clock: Date, hours, minutes, and seconds displayed with waveform; SNTP support to
synchronize to precision internet clocks
Number of Traces: Maximum of eight traces; simultaneously displays channel, zoom, memory,
and math traces
Grid Styles: Single, Dual, Quad, Octal, XY, Single+XY, Dual+XY
Waveform Display Styles: Sample dots joined or dots only
Analog Persistence Display
Analog and Color-graded Persistence: Variable saturation levels; stores each trace's
persistence data in memory
Persistence Selections: Select analog, color, or 3-D
Trace Selection: Activate Analog Persistence on all or any combination of traces
Persistence Aging Time: From 500 ms to infinity
Sweeps Displayed: All accumulated or all accumulated with last trace highlighted
Zoom Expansion Traces
Display up to 4 Zoom and 4 Math/Zoom traces; 8 Math/Zoom traces available with XMAP (Master
Analysis Package) and XMATH (Advanced Math Package) options.
Rapid Signal Processing
Processor: Intel® Pentium 4 @ 2.53 GHz (or better) with MS Windows® XP Platform
Processor Memory: Up to 1 Gbyte (WaveMaster: up to 2 Gbytes with XXL memory option)
Internal Waveform Memory
Waveform: M1, M2, M3, M4 (Store full-length waveforms with 16 bits/data point.) Or save to any
number of files (limited only by data storage media).
Setup Storage
Front Panel and Instrument Status: Save to the internal hard drive, floppy drive, or to a USB
connected peripheral device.
WM-OM-E Rev I
31
Interface
Remote Control: Through Windows Automation or LeCroy Remote Command set, supports front
panel controls and internal functions via GPIB or Ethernet.
GPIB Port (optional): Supports IEEE-488.2
Ethernet Port: 10/100Base-T Ethernet interface
USB Ports: 4 USB ports support Windows compatible devices.
External Monitor Port (standard): 15-pin D-Type SVGA compatible
Parallel Port: 1 standard
Auxiliary Output
Signal Types: Select from calibrator or control signals output on front panel.
Calibrator Signal: 5 Hz to 5 MHz (1 MHz for WavePro 7000A Series, DDA-3000A) square wave or
DC level; 0.0 to 5.0 V (selectable) into 50 ohms (0 to 1 V into 1 Mohms), or TTL Volts
Control Signals: trigger enabled, trigger out, pass/fail status, square, DC level
Auxiliary Input
Signal Types: Select External Trigger input on front panel. 1X: 100 mV/div; 10X: 1 V/div; ÷10: 10
mV/div
Math Tools (standard)
Display up to four math function traces (F1 to F4). The easy-to-use graphical interface simplifies
setup of up to two operations on each function trace. Function traces can be chained together to
perform math-on-math.
absolute value
average (summed)
average (continuous)
derivative
deskew (resample)
difference ()
enhanced resolution (to 11 bits vertical)
envelope
exp (base e)
exp (base 10)
fft (basic)
floor
histogram of 1,000 events
integral
32
invert (negate)
ln (log base e)
log (base 10)
product (X)
ratio (/)
reciprocal
rescale (with units)
roof
segment
(sinX)/X
square
square root
sum (+)
trend (datalog) of 1,000 events
zoom (identity)
WM-OM-E Rev I
X-Stream Operator’s Manual
Measure Tools (standard)
Display any 8 parameters together with statistics, including their average, high, low, and standard
deviations. Histicons provide a fast, dynamic view of parameters and wave shape characteristics.
amplitude
area
base
cycles
delay
delta delay
delta time @ level
duration
duty cycle
fall time (90-10%, 80-20%, @ level)
first
frequency
last
level @ x
maximum
mean
minimum
number of points
overshoot+
overshootpeak-to-peak
period
phase
rise time (10-90%, 20-80%, @ level)
rms
std. deviation
time @ level
top
width
x @ minimum (min.)
x @ maximum (max.)
x at max
x at min
Standard Jitter and Timing Measurements
•
Period @ level
•
Width @ level
•
Duty Cycle @ level
•
Frequency @ level
•
TIE @ level
•
Edge @ level
•
Jitter Track
•
Jitter Trend (up to 1000 points)
•
Histograms (up to 1000 points)
Pass/Fail Testing
Test multiple parameters against selectable parameter limits at the same time. Pass or fail
conditions can initiate actions including: document to local or networked files, email the image of
the failure, save waveforms, send a pulse out at the front panel auxiliary BNC output, or (with GPIB
option) send a GPIB SRQ.
WM-OM-E Rev I
33
Master Analysis Package (XMAP)
This package provides a comprehensive set of signal WaveShape Analysis tools that provide
insight into the wave shape of complex signals. Additional analysis capability provided by XMAP
includes:
y
Jitter and Timing Analysis package (JTA2)
y
8 math traces total (4 additional)
y
Parameter Math: add, subtract, multiply, or divide two different parameter measurements
y
User-definable parameter measurements and math functions, using VBScripting with MS
Excel and MATLAB
y
Histograms expanded with 19 histogram parameters and up to 2 billion events
y
Trend (datalog) of up to one million events
y
Track graphs of any measurement parameter
y
FFT capability expands the basic FFT to include; power averaging, power density, real and
imaginary components, frequency domain parameters and FFT on up to 25 Mpts.
y
Narrow Band power measurements
y
Correlation function
y
Interpolation
y
Sparse
Jitter and Timing Analysis Package (JTA2)
This package provides jitter timing and analysis using JitterTrack (time), Histogram (statistical) and
JitterFFT (frequency) views for common timing parameters, and other useful tools.
y
Jitter and Timing parameters with JitterTrack graphs of:
Cycle-to-Cycle
N-Cycle
N-Cycle with Start selection
Frequency
Period
Half Period
Width
Time Interval Error
Setup
Hold
Skew
Duty Cycle
Duty Cycle Error (Delta Width)
y
edge@lv parameter (counts edges)
y
Histograms expanded with 19 histogram parameters and up to 2 billion events
y
Trend (datalog) of up to one million events
y
Persistence Histogram; Persistence Trace
Disk Drive Measurement Package (DDM2)
This package provides disk drive parameter measurements and related mathematical functions for
performing disk drive WaveShape Analysis.
34
WM-OM-E Rev I
X-Stream Operator’s Manual
y
Disk Drive Parameters:
amplitude symmetry
auto correlation s/n
local base
local baseline separation
local maximum
local minimum
local number
local peak-peak
local time between events
local time between peaks
local time between troughs
local time at minimum
local time at maximum
local time peak-trough
y
y
y
local time over threshold
local time trough-peak
local time under threshold
narrow band phase
narrow band power
non-linear transition shift
overwrite
pulse width 50
pulse width 50pulse width 50+
resolution
track average amplitude
track average amplitudetrack average amplitude+
Correlation function
Trend (datalog) of up to one million events
Histograms expanded with 19 histogram parameters and up to 2 billion events
General
Auto Calibration: Ensures specified DC and timing accuracy is maintained for 1 year minimum.
Power Requirements:
On State:
WaveMaster 8620A, 8420
WaveMaster 8600A, 8500A, 8400A,
WavePro 7000A Series
DDA-5005A, 3000A
</= 800 watts (800 VA) depending on
accessories installed (internal printer, probes,
PC port plug-ins, etc.)
</= 650 watts (650 VA) depending on
accessories installed (internal printer, probes,
PC port plug-ins, etc.)
Standby State: 12 watts
Fuse: One 5x20 mm fuse (T10.0 A/250 V)
Battery Backup: Front panel settings retained for two years minimum
Physical Dimensions (HWD): 264 mm x 397 mm x 491 mm (10.4 in. x 15.6 in. x 19.3 in.); height
measurement excludes foot pads
Weight: 18 kg (39 lbs.)
Shipping Weight: 24 kg (53 lbs.)
WM-OM-E Rev I
35
Warranty and Service
3-year warranty; calibration recommended yearly
Optional service programs include extended warranty, upgrades, and calibration services.
Environmental Characteristics
Temperature
Operating: 5 to 40 °C
Storage (non-operating): -20 to +60 °C
Humidity
Operating: Maximum relative humidity 80% for temperatures up to 31 °C decreasing linearly to
50% relative humidity at 40 °C
Storage (non-operating): 5 to 95% RH (non-condensing) as tested per MIL-PRF-28800F
Altitude
Operating: Up to 2,000 m
Storage (non-operating): Up to 12,192 m (40,000 ft)
Random Vibration
Operating: 0.31 grms, 5 Hz to 500 Hz, 15 minutes in each of 3 orthogonal axes
Non-operating: 2.4 grms, 5 to 500 Hz, 15 minutes in each of 3 orthogonal axes
Shock
Functional Shock: 20 g peak, half sine, 11 ms pulse, 3 shocks (positive and negative) in each of 3
orthogonal axes, 18 shocks total
Certifications
CE Approved, UL and cUL Listed
CE Declaration of Conformity
The oscilloscope meets requirements of EMC Directive 89/336/EEC for Electromagnetic
Compatibility and Low Voltage Directive 73/23/EEC for Product Safety.
EMC Directive:
EN 61326/A3:2003
EMC requirements for electrical equipment for measurement,
control, and laboratory use.
Electromagnetic Emissions:
EN 55011/A2:2002, Class A Radiated and conducted emissions
(Class A)*
EN 61000-3-2/A2:2005 Harmonic Current Emissions (Class A)
EN 61000-3-3/A2:2005 Voltage Fluctuations and Flickers
(Pst = 1)
* To conform to Radiated Emissions standard, use properly shielded cables on all I/O terminals.
36
WM-OM-E Rev I
X-Stream Operator’s Manual
Warning
This is a Class A product. In a domestic environment this product may cause radio interference, in
which case the user may be required to take appropriate measures.
Electromagnetic Immunity:
EN 61000-4-2/A2:2001* Electrostatic Discharge
(4 kV contact, 8 kV air, 4 kV vertical/horizontal coupling planes)
EN 61000-4-3/A1:2003* RF Radiated Electromagnetic Field
(3 V/m, 80-1000 MHz)
EN 61000-4-5/A1:2001* Electrical Fast Transient/Burst
(1 kV AC Mains, 0.5 kV I/O signal/control)
EN 61000-4-5:1995* Surges
(1 kV AC Mains, 0.5 kV I/O signal/control)
EN 61000-4-6/A1:2001* RF Conducted Electromagnetic Field
(1 kV / 0.5 kV common mode / differential mode - AC Mains)
EN 61000-4-11:2004† Mains Dips and Interruptions
(1 cycle voltage dip, 100% short interruption)
* Meets Performance Criteria "B" limits during the disturbance, product undergoes a
temporary degradation or loss of function of performance which is self recoverable.
† Meets Performance Criteria "C" limits during the disturbance, product undergoes a
temporary degradation or loss of function of performance which requires operator
intervention or system reset.
Low Voltage Directive:
EN 61010-1:2001
Safety requirements for electrical equipment for measurement,
control, and laboratory use.
The oscilloscope has been qualified to the following EN 61010-1
limits:
Installation Categories II (Mains Supply Connector) & I
(Measuring Terminals)
Pollution Degree 2 (Normally only dry non-conductive pollution
occurs. Occasionally a temporary conductivity caused by
condensation must be expected.)
Protection Class I (Provided with terminal for protective ground)
UL and cUL Certifications:
UL Standard: UL 3111-1
Canadian Standard: CSA-C22.2 No. 1010.1-92
WM-OM-E Rev I
37
Warranty
The instrument is warranted for normal use and operation, within specifications, for a period of
three years from shipment. LeCroy will either repair or, at our option, replace any product returned
to one of our authorized service centers within this period. However, in order to do this we must first
examine the product and find that it is defective due to workmanship or materials and not due to
misuse, neglect, accident, or abnormal conditions or operation.
LeCroy shall not be responsible for any defect, damage, or failure caused by any of the following: a)
attempted repairs or installations by personnel other than LeCroy representatives or b) improper
connection to incompatible equipment, or c) for any damage or malfunction caused by the use of
non-LeCroy supplies. Furthermore, LeCroy shall not be obligated to service a product that has
been modified or integrated where the modification or integration increases the task duration or
difficulty of servicing the oscilloscope. Spare and replacement parts, and repairs, all have a 90-day
warranty.
The oscilloscope’s firmware has been thoroughly tested and is presumed to be functional.
Nevertheless, it is supplied without warranty of any kind covering detailed performance. Products
not made by LeCroy are covered solely by the warranty of the original equipment manufacturer.
Windows License Agreement
LeCroy's agreement with Microsoft prohibits users from running software on LeCroy X-Stream
oscilloscopes that is not relevant to measuring, analyzing, or documenting waveforms.
End-User License Agreement For LeCroy X-Stream Software
IMPORTANT-READ CAREFULLY: THIS END-USER LICENSE AGREEMENT (“EULA”) IS A
LEGAL AGREEMENT BETWEEN THE INDIVIDUAL OR ENTITY LICENSING THE SOFTWARE
PRODUCT (“YOU” OR “YOUR”) AND LECROY CORPORATION (“LECROY”) FOR THE
SOFTWARE PRODUCT(S) ACCOMPANYING THIS EULA, WHICH INCLUDE(S): COMPUTER
PROGRAMS; ANY “ONLINE” OR ELECTRONIC DOCUMENTATION AND PRINTED
MATERIALS PROVIDED BY LECROY HEREWITH (“DOCUMENTATION”); ASSOCIATED
MEDIA; AND ANY UPDATES (AS DEFINED BELOW) (COLLECTIVELY, THE “SOFTWARE
PRODUCT”). BY USING AN INSTRUMENT TOGETHER WITH OR CONTAINING THE
SOFTWARE PRODUCT, OR BY INSTALLING, COPYING, OR OTHERWISE USING THE
SOFTWARE PRODUCT, IN WHOLE OR IN PART, YOU AGREE TO BE BOUND BY THE
TERMS OF THIS EULA. IF YOU DO NOT AGREE TO THE TERMS OF THIS EULA, DO NOT
INSTALL, COPY, OR OTHERWISE USE THE SOFTWARE PRODUCT; YOU MAY RETURN
THE SOFTWARE PRODUCT TO YOUR PLACE OF PURCHASE FOR A FULL REFUND. IN
ADDITION, BY INSTALLING, COPYING, OR OTHERWISE USING ANY MODIFICATIONS,
ENHANCEMENTS, NEW VERSIONS, BUG FIXES, OR OTHER COMPONENTS OF THE
SOFTWARE PRODUCT THAT LECROY PROVIDES TO YOU SEPARATELY AS PART OF THE
SOFTWARE PRODUCT (“UPDATES”), YOU AGREE TO BE BOUND BY ANY ADDITIONAL
LICENSE TERMS THAT ACCOMPANY SUCH UPDATES. IF YOU DO NOT AGREE TO SUCH
ADDITIONAL LICENSE TERMS, YOU MAY NOT INSTALL, COPY, OR OTHERWISE USE
SUCH UPDATES.
THE PARTIES CONFIRM THAT THIS AGREEMENT AND ALL RELATED DOCUMENTATION
ARE AND WILL BE DRAFTED IN ENGLISH. LES PARTIES AUX PRÉSENTÉS CONFIRMENT
38
WM-OM-E Rev I
X-Stream Operator’s Manual
LEUR VOLONTÉ QUE CETTE CONVENTION DE MÊME QUE TOUS LES DOCUMENTS Y
COMPRIS TOUT AVIS QUI S’Y RATTACHÉ, SOIENT REDIGÉS EN LANGUE ANGLAISE.
1. GRANT OF LICENSE
1.1 License Grant. Subject to the terms and conditions of this EULA and payment of all applicable
fees, LeCroy grants to you a nonexclusive, nontransferable license (the “License”) to: (a) operate
the Software Product as provided or installed, in object code form, for your own internal business
purposes, (i) for use in or with an instrument provided or manufactured by LeCroy (an “Instrument”),
(ii) for testing your software product(s) (to be used solely by you) that are designed to operate in
conjunction with an Instrument (“Your Software”), and (iii) make one copy for archival and back-up
purposes; (b) make and use copies of the Documentation; provided that such copies will be used
only in connection with your licensed use of the Software Product, and such copies may not be
republished or distributed (either in hard copy or electronic form) to any third party; and (c) copy,
modify, enhance and prepare derivative works (“Derivatives”) of the source code version of those
portions of the Software Product set forth in and identified in the Documentation as “Samples”
(“Sample Code”) for the sole purposes of designing, developing, and testing Your Software. If you
are an entity, only one designated individual within your organization, as designated by you, may
exercise the License; provided that additional individuals within your organization may assist with
respect to reproducing and distributing Sample Code as permitted under Section 1.1(c)(ii). LeCroy
reserves all rights not expressly granted to you. No license is granted hereunder for any use other
than that specified herein, and no license is granted for any use in combination or in connection
with other products or services (other than Instruments and Your Software) without the express
prior written consent of LeCroy. The Software Product is licensed as a single product. Its
component parts may not be separated for use by more than one user. This EULA does not grant
you any rights in connection with any trademarks or service marks of LeCroy. The Software
Product is protected by copyright laws and international copyright treaties, as well as other
intellectual property laws and treaties. The Software Product is licensed, not sold. The terms of this
printed, paper EULA supersede the terms of any on-screen license agreement found within the
Software Product.
1.2 Upgrades. If the Software Product is labeled as an “upgrade,” (or other similar designation) the
License will not take effect, and you will have no right to use or access the Software Product unless
you are properly licensed to use a product identified by LeCroy as being eligible for the upgrade
(“Underlying Product”). A Software Product labeled as an “upgrade” replaces and/or supplements
the Underlying Product. You may use the resulting upgraded product only in accordance with the
terms of this EULA. If the Software Product is an upgrade of a component of a package of software
programs that you licensed as a single product, the Software Product may be used and transferred
only as part of that single product package and may not be separated for use on more than one
computer.
1.3. Limitations. Except as specifically permitted in this EULA, you will not directly or indirectly (a)
use any Confidential Information to create any software or documentation that is similar to any of
the Software Product or Documentation; (b) encumber, transfer, rent, lease, time-share or use the
Software Product in any service bureau arrangement; (c) copy (except for archival purposes),
distribute, manufacture, adapt, create derivative works of, translate, localize, port or otherwise
modify the Software Product or the Documentation; (d) permit access to the Software Product by
any party developing, marketing or planning to develop or market any product having functionality
similar to or competitive with the Software Product; (e) publish benchmark results relating to the
WM-OM-E Rev I
39
Software Product, nor disclose Software Product features, errors or bugs to third parties; or (f)
permit any third party to engage in any of the acts proscribed in clauses (a) through (e). In
jurisdictions in which transfer is permitted, notwithstanding the foregoing prohibition, transfers will
only be effective if you transfer a copy of this EULA, as well as all copies of the Software Product,
whereupon your right to use the Software product will terminate. Except as described in this
Section 1.3, You are not permitted (i) to decompile, disassemble, reverse compile, reverse
assemble, reverse translate or otherwise reverse engineer the Software Product, (ii) to use any
similar means to discover the source code of the Software Product or to discover the trade secrets
in the Software Product, or (iii) to otherwise circumvent any technological measure that controls
access to the Software Product. You may reverse engineer or otherwise circumvent the
technological measures protecting the Software Product for the sole purpose of identifying and
analyzing those elements that are necessary to achieve Interoperability (the “Permitted Objective”)
only if: (A) doing so is necessary to achieve the Permitted Objective and it does not constitute
infringement under Title 17 of the United States Code; (B) such circumvention is confined to those
parts of the Software Product and to such acts as are necessary to achieve the Permitted
Objective; (C) the information to be gained thereby has not already been made readily available to
you or has not been provided by LeCroy within a reasonable time after a written request by you to
LeCroy to provide such information; (D) the information gained is not used for any purpose other
than the Permitted Objective and is not disclosed to any other person except as may be necessary
to achieve the Permitted Objective; and (E) the information obtained is not used (1) to create a
computer program substantially similar in its expression to the Software Product including, but not
limited to, expressions of the Software Product in other computer languages, or (2) for any other act
restricted by LeCroy’s intellectual property rights in the Software Product. “Interoperability” will
have the same meaning in this EULA as defined in the Digital Millennium Copyright Act, 17 U.S.C.
§1201(f), the ability of computer programs to exchange information and of such programs mutually
to use the information which has been exchanged.
1.4 Prerelease Code. Portions of the Software Product may be identified as prerelease code
(“Prerelease Code”). Prerelease Code is not at the level of performance and compatibility of the
final, generally available product offering. The Prerelease Code may not operate correctly and may
be substantially modified prior to first commercial shipment. LeCroy is not obligated to make this or
any later version of the Prerelease Code commercially available. The License with respect to the
Prerelease Code terminates upon availability of a commercial release of the Prerelease Code from
LeCroy.
2. SUPPORT SERVICES
At LeCroy’s sole discretion, from time to time, LeCroy may provide Updates to the Software
Product. LeCroy shall have no obligation to revise or update the Software Product or to support
any version of the Software Product. At LeCroy’s sole discretion, upon your request, LeCroy may
provide you with support services related to the Software Product (“Support Services”) pursuant to
the LeCroy policies and programs described in the Documentation or otherwise then in effect, and
such Support Services will be subject to LeCroy’s then-current fees therefor, if any. Any Update or
other supplemental software code provided to you pursuant to the Support Services will be
considered part of the Software Product and will be subject to the terms and conditions of this
EULA. LeCroy may use any technical information you provide to LeCroy during LeCroy’s provision
of Support Services, for LeCroy’s business purposes, including for product support and
development. LeCroy will not utilize such technical information in a form that personally identifies
40
WM-OM-E Rev I
X-Stream Operator’s Manual
you.
3. PROPRIETARY RIGHTS
3.1 Right and Title. All right, title and interest in and to the Software Product and Documentation
(including but not limited to any intellectual property or other proprietary rights, images, icons,
photographs, text, and “applets” embodied in or incorporated into the Software Product, collectively,
“Content”), and all Derivatives, and any copies thereof are owned by LeCroy and/or its licensors or
third-party suppliers, and is protected by applicable copyright or other intellectual property laws and
treaties. You will not take any action inconsistent with such title and ownership. This EULA grants
you no rights to use such Content outside of the proper exercise of the license granted hereunder,
and LeCroy will not be responsible or liable therefor.
3.2 Intellectual Property Protection. You may not alter or remove any printed or on-screen
copyright, trade secret, proprietary or other legal notices contained on or in copies of the Software
Product or Documentation.
3.3 Confidentiality. Except for the specific rights granted by this EULA, neither party shall use or
disclose any Confidential Information (as defined below) of the other party without the written
consent of the disclosing party. A party receiving Confidential Information from the other shall use
the highest commercially reasonable degree of care to protect the Confidential Information,
including ensuring that its employees and consultants with access to such Confidential Information
have agreed in writing not to disclose the Confidential Information. You shall bear the responsibility
for any breaches of confidentiality by your employees and consultants. Within ten (10) days after
request of the disclosing party, and in the disclosing party's sole discretion, the receiving party shall
either return to the disclosing party originals and copies of any Confidential Information and all
information, records and materials developed therefrom by the receiving party, or destroy the same,
other than such Confidential Information as to which this EULA expressly provides a continuing
right to the receiving party to retain at the time of the request. Either party may only disclose the
general nature, but not the specific financial terms, of this EULA without the prior consent of the
other party; provided either party may provide a copy of this EULA to any finance provider in
conjunction with a financing transaction, if such provider agrees to keep this EULA confidential.
Nothing herein shall prevent a receiving party from disclosing all or part of the Confidential
Information as necessary pursuant to the lawful requirement of a governmental agency or when
disclosure is required by operation of law; provided that prior to any such disclosure, the receiving
party shall use reasonable efforts to (a) promptly notify the disclosing party in writing of such
requirement to disclose, and (b) cooperate fully with the disclosing party in protecting against any
such disclosure or obtaining a protective order. Money damages will not be an adequate remedy if
this Section 4.3 is breached and, therefore, either party shall, in addition to any other legal or
equitable remedies, be entitled to seek an injunction or similar equitable relief against such breach
or threatened breach without the necessity of posting any bond. As used herein, “Confidential
Information” means LeCroy pricing or information concerning new LeCroy products, trade secrets
(including without limitation all internal header information contained in or created by the Software
Product, all benchmark and performance test results and all Documentation) and other proprietary
information of LeCroy; and any business, marketing or technical information disclosed by LeCroy,
or its representatives, or you in relation to this EULA, and either (i) disclosed in writing and marked
as confidential at the time of disclosure or (ii) disclosed in any other manner such that a reasonable
person would understand the nature and confidentiality of the information. Confidential Information
does not include information (A) already in the possession of the receiving party without an
WM-OM-E Rev I
41
obligation of confidentiality to the disclosing party, (B) hereafter rightfully furnished to the receiving
party by a third party without a breach of any separate nondisclosure obligation to the disclosing
party, (C) publicly known without breach of this EULA, (d) furnished by the disclosing party to a third
party without restriction on subsequent disclosure, or (e) independently developed by the receiving
party without reference to or reliance on the Confidential Information.
4. TERMINATION
This EULA will remain in force until termination pursuant to the terms hereof. You may terminate
this EULA at any time. This EULA will also terminate if you breach any of the terms or conditions of
this EULA. You agree that if this EULA terminates for any reason, the License will immediately
terminate and you will destroy all copies of the Software Product (and all Derivatives), installed or
otherwise, the Documentation, and the Confidential Information (and all derivatives of any of the
foregoing) that are in your possession or under your control. The provisions of Sections 1.3, 4, 6, 7,
8, and 9 will survive any termination or expiration hereof.
5. U.S. GOVERNMENT RESTRICTED RIGHTS
If any Software Product or Documentation is acquired by or on behalf of a unit or agency of the
United States Government (any such unit or agency, the “Government”), the Government agrees
that the Software Product or Documentation is “commercial computer software” or “commercial
computer software documentation” and that, absent a written agreement to the contrary, the
Government’s rights with respect to the Software Product or Documentation are, in the case of
civilian agency use, Restricted Rights, as defined in FAR §52.227.19, and if for Department of
Defense use, limited by the terms of this EULA, pursuant to DFARS §227.7202. The use of the
Software Product or Documentation by the Government constitutes acknowledgment of LeCroy’s
proprietary rights in the Software Product and Documentation. Manufacturer is LeCroy Corporation,
700 Chestnut Ridge Road, Chestnut Ridge, NY 10977 USA.
6. EXPORT RESTRICTIONS
You agree that you will not export or re-export the Software Product, any part thereof, or any
process or service that is the direct product of the Software Product (the foregoing collectively
referred to as the “Restricted Components”), to any country, person, entity or end user subject to
U.S. export restrictions. You specifically agree not to export or re-export any of the Restricted
Components (a) to any country to which the U.S. has embargoed or restricted the export of goods
or services, which currently include, but are not necessarily limited to Cuba, Iran, Iraq, Libya, North
Korea, Sudan and Syria, or to any national of any such country, wherever located, who intends to
transmit or transport the Restricted Components back to such country; (b) to any end user who you
know or have reason to know will utilize the Restricted Components in the design, development or
production of nuclear, chemical or biological weapons; or (c) to any end-user who has been
prohibited from participating in U.S. export transactions by any federal agency of the U.S.
government. You warrant and represent that neither the BXA nor any other U.S. federal agency has
suspended, revoked or denied your export privileges. It is your responsibility to comply with the
latest United States export regulations, and you will defend and indemnify LeCroy from and against
any damages, fines, penalties, assessments, liabilities, costs and expenses (including reasonable
attorneys' fees and court costs) arising out of any claim that the Software Product, Documentation,
or other information or materials provided by LeCroy hereunder were exported or otherwise
accessed, shipped or transported in violation of applicable laws and regulations.
42
WM-OM-E Rev I
X-Stream Operator’s Manual
7. RISK ALLOCATION
7.1 No Warranty. THE SOFTWARE PRODUCT IS NOT ERROR-FREE AND THE SOFTWARE
PRODUCT AND SUPPORT SERVICES IS/ARE BEING PROVIDED "AS IS" WITHOUT
WARRANTY OF ANY KIND. LECROY, FOR ITSELF AND ITS SUPPLIERS, HEREBY
DISCLAIMS ALL WARRANTIES, WHETHER EXPRESS OR IMPLIED, ORAL OR WRITTEN,
WITH RESPECT TO THE SOFTWARE PRODUCT OR ANY SUPPORT SERVICES INCLUDING,
WITHOUT LIMITATION, ALL IMPLIED WARRANTIES OF TITLE OR NON-INFRINGEMENT,
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, ACCURACY, INTEGRATION,
VALIDITY, EXCLUSIVITY, MERCHANTABILITY, NON-INTERFERENCE WITH ENJOYMENT,
FITNESS FOR ANY PARTICULAR PURPOSE, AND ALL WARRANTIES IMPLIED FROM ANY
COURSE OF DEALING OR USAGE OF TRADE. YOU ACKNOWLEDGE THAT NO
WARRANTIES HAVE BEEN MADE TO YOU BY OR ON BEHALF OF LECROY OR OTHERWISE
FORM THE BASIS FOR THE BARGAIN BETWEEN THE PARTIES.
7.2. Limitation of Liability. LECROY’S LIABILITY FOR DAMAGES FOR ANY CAUSE
WHATSOEVER, REGARDLESS OF THE FORM OF ANY CLAIM OR ACTION, SHALL NOT
EXCEED THE GREATER OF THE AMOUNT ACTUALLY PAID BY YOU FOR THE SOFTWARE
PRODUCT OR U.S.$5.00; PROVIDED THAT IF YOU HAVE ENTERED INTO A SUPPORT
SERVICES AGREEMENT WITH LECROY, LECROY’S ENTIRE LIABILITY REGARDING
SUPPORT SERVICES WILL BE GOVERNED BY THE TERMS OF THAT AGREEMENT.
LECROY SHALL NOT BE LIABLE FOR ANY LOSS OF PROFITS, LOSS OF USE, LOSS OF
DATA, INTERRUPTION OF BUSINESS, NOR FOR INDIRECT, SPECIAL, INCIDENTAL,
CONSEQUENTIAL OR EXEMPLARY DAMAGES OF ANY KIND, WHETHER UNDER THIS EULA
OR OTHERWISE ARISING IN ANY WAY IN CONNECTION WITH THE SOFTWARE PRODUCT,
THE DOCUMENTATION OR THIS EULA. SOME JURISDICTIONS DO NOT ALLOW THE
EXCLUSION OR LIMITATION OF INCIDENTAL OR CONSEQUENTIAL DAMAGES, SO THE
ABOVE EXCLUSION OR LIMITATION MAY NOT APPLY TO YOU. THESE LIMITATIONS ARE
INDEPENDENT FROM ALL OTHER PROVISIONS OF THIS EULA AND SHALL APPLY
NOTWITHSTANDING THE FAILURE OF ANY REMEDY PROVIDED HEREIN.
7.3 Indemnification. You will defend, indemnify and hold harmless LeCroy and its officers, directors,
affiliates, contractors, agents, and employees from, against and in respect of any and all
assessments, damages, deficiencies, judgments, losses, obligations and liabilities (including costs
of collection and reasonable attorneys’ fees, expert witness fees and expenses) imposed upon or
suffered or incurred by them arising from or related to your use of the Software Product.
8. GENERAL PROVISIONS
8.1 Compliance with Laws. You will comply with all laws, legislation, rules, regulations, and
governmental requirements with respect to the Software Product, and the performance by you of
your obligations hereunder, of any jurisdiction in or from which you directly or indirectly cause the
Software Product to be used or accessed.
8.2 No Agency. Nothing contained in this EULA will be deemed to constitute either party as the
agent or representative of the other party, or both parties as joint venturers or partners for any
purpose.
8.3 Entire Agreement; Waiver; Severability. This EULA constitutes the entire agreement between
the parties with regard to the subject matter hereof. No provision of, right, power or privilege under
WM-OM-E Rev I
43
this EULA will be deemed to have been waived by any act, delay, omission or acquiescence by
LeCroy, its agents, or employees, but only by an instrument in writing signed by an authorized
officer of LeCroy. No waiver by LeCroy of any breach or default of any provision of this EULA by
you will be effective as to any other breach or default, whether of the same or any other provision
and whether occurring prior to, concurrent with, or subsequent to the date of such waiver. If any
provision of this EULA is declared by a court of competent jurisdiction to be invalid, illegal or
unenforceable, such provision will be severed from this EULA and all the other provisions will
remain in full force and effect.
8.4 Governing Law; Jurisdiction; Venue. This EULA will be governed by and construed in
accordance with the laws of the State of New York, USA, without regard to its choice of law
provisions. The United Nations Convention on Contracts for the International Sale of Goods will not
apply to this EULA. Exclusive jurisdiction and venue for any litigation arising under this EULA is in
the federal and state courts located in New York, New York, USA and both parties hereby consent
to such jurisdiction and venue for this purpose.
8.5 Assignment. This EULA and the rights and obligations hereunder, may not be assigned, in
whole or in part by you, except to a successor to the whole of your business, without the prior
written consent of LeCroy. In the case of any permitted assignment or transfer of or under this
EULA, this EULA or the relevant provisions will be binding upon, and inure to the benefit of, the
successors, executors, heirs, representatives, administrators and assigns of the parties hereto.
8.6 Notices. All notices or other communications between LeCroy and you under this EULA will be
in writing and delivered personally, sent by confirmed fax, by confirmed e-mail, by certified mail,
postage prepaid and return receipt requested, or by a nationally recognized express delivery
service. All notices will be in English and will be effective upon receipt.
8.7 Headings. The headings used in this EULA are intended for convenience only and will not be
deemed to supersede or modify any provisions.
8.8 Acknowledgment. Licensee acknowledges that (a) it has read and understands this EULA, (b)
it has had an opportunity to have its legal counsel review this EULA, (c) this EULA has the same
force and effect as a signed agreement, and (d) issuance of this EULA does not constitute general
publication of the Software Product or other Confidential Information.
Virus Protection
Because your digital storage oscilloscope (DSO) runs on a Windows-based PC platform, it must be
protected from viruses, as with any PC on a corporate network. It is crucial that the scope be kept
up to date with Windows Critical Updates, and that anti-virus software be installed and continually
updated.
Visit http://www.lecroy.com/dsosecurity for more information regarding Windows Service Pack
compatibility with LeCroy operating software, and related matters.
44
WM-OM-E Rev I
X-Stream Operator’s Manual
SAFETY
Safety Requirements
This section contains information and warnings that must be observed to keep the instrument
operating in a correct and safe condition. You are required to follow generally accepted safety
procedures in addition to the safety precautions specified in this section.
Safety Symbols
Where the following symbols appear on the instrument’s front or rear panels, or in this manual, they
alert you to important safety considerations.
This symbol is used where caution is required. Refer to the accompanying information
or documents in order to protect against personal injury or damage to the instrument.
This symbol warns of a potential risk of shock hazard.
This symbol is used to denote the measurement ground connection.
This symbol is used to denote a safety ground connection.
This symbol is used to denote a grounded frame or chassis terminal.
This symbol shows that the switch is a Standby (power) switch. When it is pressed, the
scope’s state toggles between operating and Standby mode. This switch is not a
disconnect device. The instrument can only be placed in a complete Power Off state
by unplugging the power cord from the AC supply.
This symbol is used to denote "Alternating Current."
CAUTION The CAUTION sign indicates a potential hazard. It calls attention to a procedure,
practice or condition which, if not followed, could possibly cause damage to
equipment. If a CAUTION is indicated, do not proceed until its conditions are fully
understood and met.
WM-OM-E Rev I
45
WARNING The WARNING sign indicates a potential hazard. It calls attention to a procedure,
practice or condition which, if not followed, could possibly cause bodily injury or death.
If a WARNING is indicated, do not proceed until its conditions are fully understood and
met.
CAT I
Installation (Overvoltage) Category rating per EN 61010-1 safety standard and is
applicable for the oscilloscope front panel measuring terminals. CAT I rated terminals
must only be connected to source circuits in which measures are taken to limit
transient voltages to an appropriately low level.
Operating Environment
The instrument is intended for indoor use and should be
operated in a clean, dry environment. Before using this
product, ensure that its operating environment will be
maintained within these parameters:
Temperature: 5 to 40 °C
Humidity: Maximum relative humidity 80% for
temperatures up to 31 °C decreasing linearly to 50%
relative humidity at 40 °C.
WARNING
The scope must not be operated in
explosive, dusty, or wet
atmospheres.
Altitude: Up to 2,000 m
Note: Direct sunlight, radiators, and other heat sources should be taken
into account when assessing the ambient temperature.
CAUTION
Protect the scope’s display touch
screen from excessive impacts with
foreign objects.
CAUTION
Do not exceed the maximum
specified front panel terminal (CH1,
CH1, CH2, CH3, CH4, AUX IN) voltage
levels. Refer to Specifications for
more details.
46
WM-OM-E Rev I
X-Stream Operator’s Manual
Installation (Overvoltage) Category II refers to local
distribution level, which is applicable to equipment
connected to the mains supply (AC power source).
Installation (Overvoltage) Category I refers to signal
level, which is applicable to equipment measuring
terminals that are connected to source circuits in which
measures are taken to limit transient voltages to an
appropriately low level.
Pollution Degree 2 refers to an operating environment
where normally only dry non-conductive pollution
occurs. Occasionally a temporary conductivity caused
by condensation must be expected.
Protection Class 1 refers to a grounded equipment, in
which protection against electric shock is achieved by
Basic Insulation and by means of a connection to the
protective ground conductor in the building wiring.
Note
The design of the instrument has been verified to
conform to
EN 61010-1 safety standard per the following
limits:
Installation (Overvoltage) Categories II (Mains
Supply Connector) & I (Measuring Terminals)
Pollution Degree 2
Protection Class I
Cooling
The instrument relies on forced air cooling with internal
fans and ventilation openings. Care must be taken to
avoid restricting the airflow around the apertures (fan
CAUTION
holes) at the sides and rear of the scope. To ensure
Do not block the ventilation holes
adequate ventilation it is required to leave a 10 cm (4
located on both sides and rear of the
inch) minimum gap around the sides and rear of the
scope.
instrument.
The instrument also has internal fan control circuitry that
regulates the fan speed based on the ambient
temperature. This is performed automatically after
start-up with no manual intervention required.
CAUTION
Do not allow any foreign matter to
enter the scope through the
ventilation holes, etc.
AC Power Source
100 to 240 Vrms (+/-10%) AC at 50/60 Hz; 115 Vrms
(+/-10%) AC at 400 Hz; Automatic AC voltage selection;
Installation Category: 300V CAT II
No manual voltage selection is required because the
instrument automatically adapts to line voltage.
WaveMaster 8620A, 8420
WM-OM-E Rev I
</= 800 watts (800 VA)
depending on accessories
installed (internal printer,
probes, PC port plug-ins,
etc.)
Note:
The instrument automatically adapts itself to the
AC line input within the following ranges:
Voltage
Range
90 to 132 VAC
180 to 264
VAC
Frequency
Range
45 to 440 Hz
45 to 66 Hz
47
WaveMaster 8600A, 8500A,
8400A,
WavePro 7000A Series
DDA-5005A, 3000A
</= 650 watts (650 VA)
depending on accessories
installed (internal printer,
probes, PC port plug-ins,
etc.)
The power supply of the scope is protected against short
circuit and overload by a 5x20 mm fuse (T10.0 A/250 V).
See “Fuse Replacement” section for replacement
instructions.
Power and Ground Connections
The instrument is provided with a grounded cord set
containing a molded three-terminal polarized plug and a
standard IEC320 (Type C13) connector for making line
voltage and safety ground connection. The AC inlet
ground terminal is connected directly to the frame of the
instrument. For adequate protection against electrical
shock hazard, the power cord plug must be inserted into
a mating AC outlet containing a safety ground contact.
In Standby mode the scope is still connected to the AC
supply. The instrument can only be placed in a complete
Power Off state by physically disconnecting the power
cord from the AC supply.
The scope should be positioned to allow easy access to
the socket-outlet. To disconnect the scope from the AC
supply, unplug the instrument’s power cord from the AC
outlet after the scope is placed in Standby state.
WARNING
Electrical Shock Hazard!
Any interruption of the protective
conductor inside or outside of the
scope, or disconnection of the safety
ground terminal creates a hazardous
situation.
Intentional interruption is prohibited.
CAUTION
The outer shells of the front panel
terminals (CH1, CH2, CH3, CH4, AUX
IN, AUX OUT) are connected to the
instrument’s chassis and therefore to
the safety ground.
See “Standby (Power) Switch and Scope Operational
States” section for more information.
Standby (Power) Switch and Scope Operational States
The front Standby (Power) switch controls the operational state of the scope. This toggle switch is
activated by momentarily pressing and releasing it. The color of the LED below the switch indicates
the status of the scope as follows:
On (LED Green)* scope is fully powered and operational
Standby (LED Off)* scope is powered off (except for some “housekeeping” circuits)
Standby (LED Red) scope’s computer subsystems (hard drive, etc.) are in Standby (reduced
Power mode). All other scope subsystems are fully powered.
* Factory Settings
48
WM-OM-E Rev I
X-Stream Operator’s Manual
The scope’s factory settings result in only two basic scope states: On (LED Green) or Standby
(LED Off). In this case of Standby (LED Off), the scope is powered off with the exception of some
“housekeeping” circuitry (approximately 12 watts dissipation). The scope can only be placed in a
complete power off state by unplugging the instrument’s power cord from the primary power source
(AC outlet). It is recommended that the power cord be unplugged from the AC outlet if the scope is
not being used for an extended period of time.
You have the ability to change the scope original factory settings via the “Power Options
Properties” menu in Windows by following the path: Settings Power Options. It is important to note
that the Windows Power Option named “Standby” provides control of only the scope’s computer
subsystems (CPU, hard drive, etc.) and does not affect the other subsystems within the scope. In
general, these other subsystems remain fully powered. For additional information on setting these
Power Options, see the Windows Help menu or other related technical documentation. In terms of
control buttons, this scope uses only a power button/switch and therefore references to a sleep
button are not applicable.
The scope can always be placed in the Standby state (LED Off) Power Off (except for some
“housekeeping” circuits) by pressing and holding in the Standby toggle switch for approximately 5
seconds.
Fuse Replacement
Set the scope’s Standby (power) switch to Standby mode
(LED off) and disconnect the power cord before
inspecting or replacing the fuse. Open the black fuse
WARNING
holder (located at the rear of the instrument directly to the
For continued fire protection at all
right of the AC inlet) using a small, flat-bladed
screwdriver. Remove the old fuse, replace it with a new line voltages, replace fuse with the
5x20 mm “T” rated 10.0 A/250 V fuse, and reinstall the specified type and rating only.
Disconnect the power cord before
fuse holder.
replacing fuse.
Calibration
The recommended calibration interval is one year. Calibration should be performed by qualified
personnel only.
Cleaning
Clean only the exterior of the instrument, using a damp,
soft cloth. Do not use chemicals or abrasive elements.
Under no circumstances allow moisture to penetrate the
WARNING
instrument. To avoid electrical shock, unplug the power
Electrical Shock Hazard!
cord from the AC outlet before cleaning.
No operator serviceable parts inside.
Do not remove covers.
Refer servicing to qualified personnel.
WM-OM-E Rev I
49
Abnormal Conditions
Operate the instrument only as intended by the
manufacturer.
WARNING
If you suspect the scope’s protection has been impaired,
disconnect the power cord and secure the instrument
Any use of the scope in a manner not
against any unintended operation.
specified by the manufacturer may
impair the instrument’s safety
The scope’s protection is likely to be impaired if, for
example, the instrument shows visible damage or has protection. The instrument and
related accessories should not be
been subjected to severe transport stresses.
directly connected to human
Proper use of the instrument depends on careful reading subjects or used for patient
of all instructions and labels.
monitoring.
50
WM-OM-E Rev I
X-Stream Operator’s Manual
BASIC CONTROLS
Front Panel Controls
The control buttons of the instrument's front panel are logically grouped into analog and special
functional areas. Analog functions are included in the Horizontal, Trigger, and Vertical groups of
control buttons and knobs.
Sometimes you may want to change a value without using the numeric keypad. In that case, simply
touch once inside the data entry field in the scope dialog area (the field will be highlighted in yellow),
then use the Adjust group of buttons and single knob to dial in values into the selected field.
By default, the control knob makes coarse adjustments (that is, digits to the left of the decimal point).
Press the Fine button to adjust digits to the right of the decimal point. To enter exact values, you
can also display a keypad by touching twice inside the data entry field. Then use the keypad to type
in the value. The Select button steps through a dialog from one control to the next.
Example Data Entry Field
Note: You can set the granularity (delta) of the coarse adjustment in two ways:
• By pressing and holding the Fine front panel button while turning the Adjust knob. In this case you can read the changing
delta in the data entry field that is selected:
• By double-tapping inside the data entry field, then touching the Advanced checkbox in the pop-up numeric keypad. The
keypad presents Coarse delta up/down buttons to set the delta:
to leave the Fine checkbox unchecked to adjust the coarse delta.
WM-OM-E Rev I
. In the pop-up keypad, be sure
51
Trigger Knobs:
Level
Selects the trigger threshold level. The Level is indicated in the Trigger
label:
Trigger Buttons:
Setup
Activates the trigger setup menu to select the trigger type and the trigger
conditions.
Stop
Prevents the scope from triggering on a signal. If you boot up the
instrument with the trigger in Stop mode, the message "no trace available"
will be displayed. Press Auto to display your trace.
Auto
Triggers the scope after a time-out, even if the trigger conditions are not
met.
Normal
Triggers the scope each time a signal is present that meets the conditions
set for the type of trigger selected.
Single
Arms the scope to trigger once (single-shot acquisition) when the input
signal meets the trigger conditions set for the type of trigger selected. If
the scope is already armed, it will force a trigger.
Horizontal Knobs:
Delay
Horizontally positions the scope trace on the display so you can observe
the signal prior to the trigger time. Delay adjusts the pre- and post-trigger
time.
Time/Division
Sets the time/division of the scope timebase (acquisition system).
LeCroy's SMART Memory feature automatically optimizes the memory
and sample rate for maximum resolution.
Horizontal Buttons:
Smart Memory
Calls up the SMART Memory dialog from the Horizontal setup menus.
Zero Delay
Sets the horizontal delay to zero. The trigger point is positioned in the
middle of the display grid.
Setup
Activates the TIMEBASE menu to allow you to select acquisition
conditions, including the sample mode, maximum memory length, etc.
Vertical Knobs:
Offset
52
Adjusts the vertical offset of a channel.
WM-OM-E Rev I
X-Stream Operator’s Manual
Volts/Div
Adjusts the Volts/Division setting (vertical gain) of the channel selected.
Channel Buttons:
1, 2, 3, 4
Turns a channel on or off. These buttons activate the dialog that lets you
change the channel's setup conditions including coupling, gain, and
offset. They are used also to select multiple grids, to automatically set the
gain (FIND SCALE), or to automatically display a zoom of the signal.
Press twice to toggle the trace on and off.
Wavepilot Control
Knobs:
Position
Adjusts the horizontal position of a zoom trace on the display. The zoom
region is highlighted in color on the source trace.
Zoom
Adjusts the horizontal zoom (magnification factor) of the selected zoom
trace.
Position
Zoom
Adjusts the vertical position of the selected zoom trace on the display.
Adjusts the vertical zoom (magnification factor) of the selected zoom trace
on the display.
Wavepilot Control
Buttons:
Reset
Resets the zoom factors.
Math
Provides access to the Math setup dialog.
Measure
Provides access to the Measure setup dialog.
Analysis
Provides access to the Analysis setup dialogs.
Special Features
Buttons:
Auto Setup
Automatically sets the scope's horizontal timebase (acquisition system),
vertical gain and offset, as well as trigger conditions, to display a wide
variety of signals.
Cursors
The center button calls up the "Standard Cursors" setup dialog. The other
two buttons control the placement of the cursors on your waveform.
Default Setup
Sets the scope's horizontal timebase (acquisition system), vertical gain
and offset, and trigger conditions to default settings.
Drive Analysis
This button is found on DDA instruments in place of Default Setup. When
pressed, it displays the DDA setup dialogs.
Serial Data
This button is found on Serial Data Analyzers in place of Default Setup.
When pressed, it displays the SDA setup dialogs.
WM-OM-E Rev I
53
Help
Displays the on-line Help manual. You can choose to receive control help,
or to search for the information you need using the Table of Contents and
Index. Control Help displays help for a particular button, menu item, data
field, etc. contained in the dialogs.
Save/Recall
Calls up the dialogs for saving and recalling waveforms and setups, and
for disk utilities.
Analog
Persist
Provides a three dimensional view of the signal: time, voltage, and a third
dimension related to the frequency of occurrence, as shown by a
color-graded (thermal) or intensity-graded display.
QuickZoom
Automatically displays magnified views of up to four signal inputs on
multiple grids. With four input signals, the signals are displayed along with
four zoom traces, each on its own grid. This button turns off all other
traces.
General Control
Buttons:
Print Screen
Prints the displayed screen to a file, a printer, the clipboard, or attaches it
as an e-mail. Select the device and format it in the Utilities Hardcopy
dialog.
Utilities
For setup of scope features including hardcopy devices and formats, date
and time, and remote control interfaces, etc.; or for checking status,
options, etc..
Touch Screen
(toggle switch)
Activates or deactivates the touch screen.
Clear Sweeps
Clears data from multiple sweeps (acquisitions) including: persistence
trace displays, averaged traces, parameter statistics, and Histicons.
During waveform readout, cancels readout.
STANDBY Lamp:
The STANDBY lamp indicates when the scope has placed itself in
standby mode. In this mode, current settings are retained.
54
WM-OM-E Rev I
X-Stream Operator’s Manual
On-screen Toolbars, Icons, and Dialog Boxes
Menu Bar Buttons
The menu bar buttons at the top of the scope's display are designed for quick setup of common
functions. At the right end of the menu bar is a quick setup button that, when touched, opens the
setup dialog associated with the trace or parameter named beside it. The named trace or
parameter is the one whose setup dialog you last opened:
. This button also
after front panel buttons Autosetup and QuickZoom
are
appears as an undo button
pressed. If you want to perform an Undo operation, it must be the very next operation after you
perform the Autosetup or QuickZoom operation.
Many of the menu bar buttons give you access to the same functions as do the front panel buttons.
Refer to this Table of Equivalent Functions.
Display Buttons
WM-OM-E Rev I
Front Panel Push Buttons
55
(icon in Channels dialog
(zooms all displayed traces)
zooms one trace)
(then Math Setup...)
(then Measure Setup...)
(then Utilities Setup...)
56
WM-OM-E Rev I
X-Stream Operator’s Manual
Dialog Boxes
The dialog area occupies the bottom one-third of the screen. To expand the signal display area,
you can minimize each dialog box by touching the Close tab at the right of the dialog box.
Alternate Access Methods
The instrument often gives you more than one way to access dialogs and menus.
Mouse and Keyboard Operation
In the procedures we focus on touch-screen operation, but if you have a mouse connected to the
instrument, you can also click on objects. Likewise, if you have a keyboard connected, you can use
it instead of the virtual keyboard provided by the instrument.
If you want to connect a mouse to the instrument, use only a USB mouse.
Tool Bar Buttons
The procedures also focus on the use of the menu bar at the top of the screen to access dialogs
and menus. However, on several dialogs common functions are accessible from a row of buttons
that save you a step or two in accessing their dialogs. For example, at the bottom of the Channel
Setup dialog, these buttons perform the following functions:
Calls up the Measure menu. You can then select a parameter from this menu
without leaving the Channel Setup dialog. The parameter automatically appears
below the grid.
Creates a zoom trace of the channel trace whose dialog is currently displayed.
Calls up the Math menu. You can then select a math function from this menu
without leaving the Channel Setup dialog. A math trace of the channel whose
dialog is currently open is automatically displayed.
Loads the channel trace into the next available memory location (M1 to M4).
Automatically performs a vertical scaling that fits the waveform into the grid.
Automatically moves the channel trace whose dialog is currently open onto the
next grid. If you have only one grid displayed, a new grid will be created
automatically, and the trace moved.
Another example is these buttons that appear at the bottom of the Measure Px dialogs. Each button
opens a menu from which to choose a math trace (F1 to Fx [The number of math traces available
WM-OM-E Rev I
57
depends on the software options loaded on your scope. See specifications.]) to display the
,
,
functions named in the buttons:
can remain in the Measure dialog to set up other options.
. By using these buttons you
Trace Descriptors
Vertical and horizontal trace descriptors (labels) are displayed below the grid. They provide a
summary of your channel, timebase, and trigger settings. To make adjustments to these settings,
touch the respective label to display the setup dialog for that function.
Channel trace labels show the vertical settings for the trace,
as well as cursor information if cursors are in use. In the title
bar of the label are also included indicators for (SinX)/X
interpolation, waveform inversion (INV), deskew (DSQ),
coupling (DC/GND), bandwidth limiting (BWL), and
averaging (AVG). These indicators have a long and short
form
.
Besides channel traces, math and parameter measurement
labels are also displayed. Labels are displayed only for
traces that are turned on.
The title bar of the TimeBase label shows the trigger delay
setting. Time per division and sampling information is given
below the title bar.
The title bar of the Trigger label shows the trigger mode:
Auto, Normal, or Stopped. Below the title bar is given the
coupling (DC), trigger type (Edge), source (C1), level (0
mV), and slope (Positive).
Shown below the TimeBase and Trigger labels is setup
information for horizontal cursors, including the time
between cursors and the frequency.
58
WM-OM-E Rev I
X-Stream Operator’s Manual
Trace Annotation
The instrument gives you the ability to add an identifying label, bearing your own text, to a
waveform display:
For each waveform, you can create multiple labels and turn them all on or all off. Also, you can
position them on the waveform by dragging or by specifying an exact horizontal position.
To Annotate a Waveform
1. Touch the waveform you want to annotate, then Set label... in the pop-up menu. A dialog
box opens in which to create the label. If you are creating a label for the first time for this
waveform, Label1 is displayed with default text. If you are modifying an existing label,
under Labels touch the label you want to change.
WM-OM-E Rev I
59
Note 1: If the dialog for the trace you want to annotate is currently displayed, you can touch the label button
at
the bottom to display the Trace Annotation setup dialog.
Note 2: You may place a label anywhere you want on the waveform. Labels are numbered sequentially according to the
order in which they are added, and not according to their placement on the waveform.
2. If you want to change the label's text, touch inside the Label Text field. A pop-up keyboard
appears for you to enter your text. Touch O.K. on the keyboard when you are done. Your
edited text will automatically appear in the label on the waveform.
3. To place the label precisely, touch inside the Horizontal Pos. field and enter a horizontal
value, using the pop-up numeric keypad.
4. To add another label, touch the Add label button. To delete a label, select the label from
the list, then touch the Remove label button.
5. To make the labels visible, touch the View labels checkbox.
To Turn On a Channel Trace Label
Note: If you want to display each trace on its own grid automatically, enable Autogrid by touching Display in the menu bar,
then Autogrid in the drop-down menu.
•
On the front panel, press a channel select button, such as
for that input channel and turn on the channel.
•
To turn on a math function trace, touch Math in the menu bar, then Math Setup... in the
drop-down menu. Touch the On checkbox for the trace you want to activate.
•
You can also quickly create traces (and turn on the trace label) for math functions and
memory traces, without leaving the Vertical Adjust dialog, by touching the icons at the
bottom of the Vertical Adjust dialog:
,
, to display the trace label
,
,
.
Whenever you turn on a channel, math, or memory trace via the menu bar, the dialog at the bottom
of the screen automatically switches to the vertical setup or math setup dialog for that selection.
You can configure your traces from here, including math setups.
of the "Vertical
The channel number appears in the Vertical Adjust tab
Adjust" dialog, signifying that all controls and data entry fields are dedicated to the selected trace.
Screen Layout
The instrument's screen is divided into three areas:
60
y
menu bar
y
signal display area
WM-OM-E Rev I
X-Stream Operator’s Manual
y
dialog area
Menu Bar
The top of the screen contains a toolbar of commonly used functions. Whenever you touch one of
these buttons, the dialog area at the bottom of the screen switches to show the setup for that
function.
Signal Display Grid
You can set up the signal display area by touching
in the toolbar, then the
tab. The display dialog offers a choice of grid combinations and a means to set the
grid intensity.
Dialog Area
The lower portion is where you make selections and input data. The dialog area is controlled by
both toolbar touch buttons and front panel push buttons. Similarities between functions are shown
in this Table of Equivalent Functions.
WM-OM-E Rev I
61
(icon in
(zooms all displayed traces)
Channels dialog
zooms one
trace)
62
WM-OM-E Rev I
X-Stream Operator’s Manual
(then Math
Setup...)
(then Measure
Setup...)
(then Utilities
Setup...)
WM-OM-E Rev I
63
INSTALLATION
Hardware
Instrument Rear Panel
(1) Mouse; (2) Keyboard; (3) USB Port; (4) USB Port; (5) Centronics Port; (6) External VGA Monitor; (7) RS-232-C
Port; (8) Ethernet Port; (9) USB Port; (10) USB Port; (11) Line In; (12) Speakers; (13) Microphone; (14) Ground
Connector; (15) External Clock Input with Grounded EMI Shield installed (required when port is not in use)
Software
Checking the Scope Status
To find out the scope's software and hardware configuration, including software version and
64
WM-OM-E Rev I
X-Stream Operator’s Manual
installed options, proceed as follows:
.
1. In the menu bar, touch
tab.
2. Touch the
You can find information related to hard drive memory, etc. as follows:
1. Minimize the instrument application by touching
drop-down menu.
, then selecting Minimize in the
2. Touch the Start taskbar button and, per usual Windows® operation, open Windows
Explorer.
Loading Software Upgrades
You can download software upgrades from the LeCroy Web site at www.lecroy.com. Follow the
on-screen instructions to download the software. Click the Release Notes link to learn about new
features and fixes.
Default Settings
WaveMaster and WavePro 7000A Series Scopes
You can reset the scope to default settings by simply pressing the Default Setup push button
on the front panel. This feature turns on Channel1 and Channel 2, with no processing
enabled.
Other default settings are as follows:
Vertical
Timebase
Trigger
Coupling: DC (WaveSurfer), DC50
(WaveMaster, DDA, SDA), AC1M
(WavePro)
Channel: C1
Level: 0 mV
50 mV/div
50.0 ns/div
0 V offset
10.0 GS/s (WaveMaster, WavePro,
DDA, SDA)
edge trigger
5 GS/s (WaveRunner)
positive edge
1 GS/s (WaveSurfer)
0 s delay
WM-OM-E Rev I
Auto trigger mode
65
DDAScopes
On your front panel, the Default Setup push button does not exist. For these instruments, therefore,
to recall a default setup
1. Press the Save/Recall push button to the left of the Drive Analysis push button.
Note: You can also touch File in the menu bar, then Recall Setup... in the drop-down menu.
2. Touch the "Recall Setup" tab in the dialog.
3. Then touch the on-screen Recall Default button:
.
Adding a New Option
To add a software option you need a key code to enable the option. Call LeCroy Customer Support
to place an order and receive the code.
To add the software option do the following:
1. In the menu bar, touch
2. In the dialog area, touch the
3. Touch
.
tab.
.
4. Use the pop-up keyboard to type the key code. Touch O.K. on the keyboard to enter the
information.
5. The name of the feature you just installed is shown below the list of key codes. You can use
the scroll buttons to see the name of the option installed with each key code listed:
66
WM-OM-E Rev I
X-Stream Operator’s Manual
The full array of installed software and hardware options is displayed on the left side of the
dialog:
WM-OM-E Rev I
67
RESTORING SOFTWARE
Using the Recovery Disk – non-Windows XP Scopes
Your oscilloscope comes with a recovery disk to be used in the event that it becomes necessary to
reload the operating software. Follow the instructions displayed on-screen when loading the
recovery software.
System Recovery – Windows XP Scopes
Your oscilloscope was designed to operate very reliably for many years. However, the application
software that operates the instrument runs on a Windows platform. The loading or incomplete
removal of additional Windows applications may eventually cause problems in the stability of the
operating system. In severe cases, it may be necessary to reload the base operating system and
oscilloscope application. This can be done by using a recovery routine to restore a clean copy of
the image originally installed on the C: drive. Any user data and calibration data located within the
D: partition will not be affected by the recovery process.
LeCroy has provided a recovery application, along with a backup image, in an extra partition on the
instrument’s hard drive. The recovery process is easy to perform, using the instructions provided
below.
After the recovery procedure is done, you must activate Windows, either by internet connection to
Microsoft’s Web site or by telephone. For this you will need to supply the Windows Product Key
number, which is affixed to the rear of the scope.
Note: The recovery process will produce a replica of the operating system and oscilloscope application software to the
revision levels that were current at the time the oscilloscope was manufactured. Any further revisions of the application
software, Windows operating system, and virus scan definition files will not be upgraded automatically. After completion of
the disk image recovery, it is highly recommended that you search the vendors’ Web sites to upgrade the individual
components to their current revision level. The current oscilloscope application software can be downloaded directly from
the LeCroy Web site at www.lecroy.com.
Since the calibration data for the oscilloscope is stored in the D: drive, the current calibration constants will not be
overwritten during the recovery process.
Recovery Procedure
1. Connect an network cable to the LAN port at the rear of the scope if you intend to activate
windows through the internet.
2. Connect a keyboard and a mouse to the scope.
3. Apply power to the scope.
68
WM-OM-E Rev I
X-Stream Operator’s Manual
4. As soon as the LeCroy logo appears on the screen, press and hold down the F4 key until
the recovery software logo appears momentarily:
5. Then the cME console End User License Agreement is displayed. Read the agreement,
and click Accept:
WM-OM-E Rev I
69
6. The Phoenix cME Console main page is displayed. Click Click here to start recover:
7. The FirstWare Recover splash screen is displayed momentarily:
70
WM-OM-E Rev I
X-Stream Operator’s Manual
8. The recovery starts, and the FirstWare Progress screen is displayed. No further selections
are required. The recovery takes about 10 minutes.
Note: The screen will blank on occasion for prolonged periods. This is normal and is not an indication of any malfunctioning
of the recovery process.
9. After the recovery is completed, the X-Stream software installer screen appears. Click
Next to continue:
10. When the X-Stream installation is completed, reboot the scope.
Now you must activate Windows by internet connection to Microsoft’s Web site or by telephone. For
this you will need to supply the Windows Product Key number, which is affixed to the rear of the
WM-OM-E Rev I
71
scope.
Windows Activation
1. Click Start in the task bar, then select All Programs Æ Activate Windows.
Note: After Windows Activation is completed, this selection will no longer appear in the All Programs menu.
2. Select an activation method: internet or phone. Then click Next.
3. If you elected to activate by internet, enter the Activation ID (Product Key) number when
prompted to do so, then click Next. Windows Activation will begin.
4. If you elected to activate by phone, select the country the scope is located in. Then dial the
number provided. You will be asked to repeat over the phone the installation ID listed on
72
WM-OM-E Rev I
X-Stream Operator’s Manual
the screen; then a 7-part number will be provided to you to enter in the empty boxes at the
bottom of the screen. Click Next when you are done.
5. When activation is completed, an acknowledgement screen will appear. Click OK.
6. Check the revision levels of the X-Stream software, virus definitions, and Windows updates.
Visit the vendors’ Web sites and download all necessary updates.
WM-OM-E Rev I
73
Restarting the Application
Upon initial power-up, the scope will load the instrument application software automatically. If you
exit the application and want to reload it, touch the shortcut icon on the desktop:
.
If you minimize the application, touch the appropriate task bar or desktop button to maximize it:
.
Restarting the Operating System
If you need to restart the Windows® operating system, you will have to reboot the scope by
pressing and holding in the power switch for 10 seconds, then turning the power back on.
74
WM-OM-E Rev I
X-Stream Operator’s Manual
Removable Hard Drive
The removable hard drive option replaces the standard internal hard drive with a removable hard
drive that is installed at the rear of the scope, in the slot normally occupied by the CDROM drive.
The kit includes two hard drives, which can be used interchangeably. It also includes a USB
CDROM for loading of new software.
Caution
The Removable Hard Drive Is Not Hot-swappable
To avoid damage to the drive or the oscilloscope, shut off power to the oscilloscope before
you insert or remove the hard drive. Ensure that the protective cover is installed over the
drive at all times.
Proper Orientation of Drive
WM-OM-E Rev I
75
Protective Cover
External Monitor
If your X-Stream scope's processor runs at greater than 1 GHz, the external monitor must be
configured manually. You can find out your processor's speed by touching Utilities in the menu bar,
then touching the Status tab of the "Utilities" dialog. If the speed is greater than 1 GHz, proceed as
follows:
1. Connect the external monitor to the VGA port at the rear of the instrument (item 6 in the
diagram).
2. Plug in the monitor's power cord, and apply power to the monitor.
3. After boot-up, touch Display in the menu bar, then Display Setup... in the drop-down
menu.
4. Touch the Monitor tab of the "Display" dialog:
76
WM-OM-E Rev I
X-Stream Operator’s Manual
5. Touch Enable External Monitor.
6. Touch inside the Brightness field and adjust brightness as necessary.
Writable CD Drive option
If your scope is equipped with this option, follow these setup instructions to install the software.
Note: Install the software only in scopes that have CD drive model SM-CD-W224EA installed.
1. Connect a keyboard and mouse to the scope.
2. Load the Easy CD Creator 5 Basic installation CD into the CD drive.
3. Click Yes to begin installation:
WM-OM-E Rev I
77
4. Select a language:
5. Click Next when the Wizard appears:
78
WM-OM-E Rev I
X-Stream Operator’s Manual
6. Select Complete setup:
WM-OM-E Rev I
79
7. Click Install:
8. When installation is completed, the scope will need to be rebooted.
The install Wizard places a shortcut icon on the desktop.
Note: If in the future it is necessary to run recovery software, this Easy CD Creator 5 Basic installation software will need to
be reinstalled also.
80
WM-OM-E Rev I
X-Stream Operator’s Manual
CONNECTING TO A SIGNAL
ProLink Interface
LeCroy's ProLink Adapters (LPA) give you the ability to connect your signal in one of three ways:
•
BMA connector
•
SMA using the BMA-to-SMA adapter
•
BNC using BMA-to-BNC adapter
(1) BMA-to-SMA Adapter; (2) BMA-to-BNC Adapter
(1) BMA Female Connector; (2) ProLink BMA-to-SMA Adapter Installed; (3) ProLink BMA-to-BNC Adapter Installed
Note: When connecting an active probe to the instrument, be sure to use a ProLink BMA-to-BNC adapter (item 3 in the
figure). Do not plug the probe directly into the front panel connector (item 1) without an adapter.
WM-OM-E Rev I
81
Connecting the Adapters
The mating end of the ProLink adapter has four fastening clips, as shown here:
When installing an adapter on the instrument's connector panel, align the male 6-pin connector with
the female connector and push the adapter straight in. There will be some resistance and you'll
hear clicks as the four clips slide into place. Then tighten the captive screws.
When removing an adapter, loosen the two captive screws. Push down on the adapter to unseat
the clips. This will require some force and will be initially noisy, but no damage will result to the
connector, the floating female BMA connector, or the pins, which can be 15 degrees off axis when
being mated or unmated.
ProBus Interface
LeCroy's ProBus® probe system provides a complete measurement solution from probe tip to
oscilloscope display. ProBus allows you to control transparent gain and offset directly from your
front panel. It is particularly useful for voltage, differential, and current active probes. It uploads gain
and offset correction factors from the ProBus EPROMs and automatically compensates to achieve
fully calibrated measurements.
This intelligent interconnection between your instrument and a wide range of accessories offers
important advantages over standard BNC and probe ring connections. ProBus ensures correct
input coupling by auto-sensing the probe type, thereby eliminating the guesswork and errors that
occur when attenuation or amplification factors are set manually.
82
WM-OM-E Rev I
X-Stream Operator’s Manual
AP-1M Hi-Z Adapter
The AP-1M adapter provides a means to connect a high-impedance input to your instrument. In
order to achieve high bandwidth with excellent signal integrity, these instruments have a +/-4 V
dynamic range and 50 termination to ground. However, for applications that combine one or more
high-speed signals with slower, higher-voltage signals, the AP-1M provides a 1 M input impedance
path and a full-scale range of +/-8 V. It is also suitable as an interface for current probes that require
a 1 M input path.
In addition to acting as a ProLink-to-ProBus adapter, the AP-1M also enables a much larger offset
voltage range (up to +/-50 V).
The AP-1M is supplied with a PP005A passive probe.
Auxiliary Output Signals
In addition to a calibration signal, the following signals can be output through the AUX OUTPUT
connector:
Square Wave
Trigger Out -- can be used to trigger another scope
DC level -- a reference level
WM-OM-E Rev I
83
Trigger Enabled -- can be used as a gating function to trigger another
instrument when the scope is ready
Pass/Fail -- allows you to set a pulse duration from 1 ms to 500 ms;
generates a pulse when pass/fail testing is active and conditions are met.
Aux Output Off -- turns off the auxiliary output signal
To Set Up Auxiliary Output
1. In the menu bar, touch Utilities, then Utilities Setup... in the drop-down menu.
2. Touch the Aux Output tab.
3. If you simply want a 1 kHz, 1 V square wave, touch the button so labeled.
4. If you want a specialized output, touch one of the buttons under Use Auxiliary Output
For.
5. Touch inside the Amplitude data entry field and enter a value, using the pop-up numeric
keypad. If you want a TTL level signal, touch the TTL Level checkbox. The Amplitude field
will accordingly become unavailable.
6. If you selected Square Wave, touch inside the Frequency data entry field and enter a
value, using the pop-up keypad. You can set a value from 5.0 Hz to 5 MHz.
7. If you selected Pass/Fail, touch inside the Pulse Duration field and enter a value from 1
ms to 500 ms, using the pop-up numeric keypad.
84
WM-OM-E Rev I
X-Stream Operator’s Manual
SAMPLING MODES
Depending on your timebase, you can choose either Single-shot (Real Time)
, or RIS
, Sequence
mode sampling.
To Select a Sampling Mode
1. In the menu bar, touch Timebase, then Horizontal Setup... in the drop-down menu.
2. In the "Horizontal" dialog, touch a Sample Mode button.
3. If you chose Sequence Mode, touch the "Smart Memory" tab, then touch inside the Num
Segments data entry field
numeric keypad.
and enter a value, using the pop-up
4. If you want to use a timeout condition for Sequence mode, touch the Enable Timeout
checkbox; then touch inside the Timeout data entry field
using the pop-up numeric keypad.
and enter a value,
Single-shot sampling mode
Basic Capture Technique
A single-shot acquisition is a series of digitized voltage values sampled on the input signal at a
uniform rate. It is also a series of measured data values associated with a single trigger event. The
acquisition is typically stopped a defined number of samples after this event occurs: a number
determined by the selected trigger delay and measured by the timebase. The waveform's
horizontal position (and waveform display in general) is determined using the trigger event as the
definition of time zero.
You can choose either a pre- or post-trigger delay. Pre-trigger delay is the time from the left-hand
edge of the display grid forward to the trigger event, while post-trigger delay is the time back to the
event. You can sample the waveform in a range starting well before the trigger event up to the
moment the event occurs. This is 100% pre-trigger, and it allows you to see the waveform leading
up to the point at which the trigger condition was met and the trigger occurred. (The instrument
offers up to the maximum record length of points of pre-trigger information.) Post-trigger delay, on
the other hand, allows you to sample the waveform starting at the equivalent of 10,000 divisions
after the event occurred.
Because each instrument input channel has a dedicated ADC (Analog-to-Digital Converter), the
voltage on each is sampled and measured at the same instant. This allows very reliable time
measurements between the channels.
WM-OM-E Rev I
85
On fast timebase settings, the maximum single-shot sampling rate is used. But for slower
timebases, the sampling rate is decreased and the number of data samples maintained.
The relationship between sample rate, memory, and time can be simply defined as:
and
Sequence SAMPLING Mode Working With Segments
In sequence mode, the complete waveform consists of a number of fixed-size segments acquired
in single-shot mode (see the instrument specifications for the limits). Select the number of
segments to be captured, then select each segment individually and use it for processing with math
and measure tools.
Sequence mode offers a number of unique capabilities. With it, you can limit dead time between
trigger events for consecutive segments. The instrument can capture in fine detail complicated
sequences of events over large time intervals, while ignoring the uninteresting periods between the
events. You can also make time measurements between events on selected segments using the
full precision of the acquisition timebase.
Each individual segment can be zoomed or used as input to math functions.
The instrument uses the sequence timebase setting to determine the capture duration of each
segment: 10 x time/div. Along with this setting, the scope uses the desired number of segments,
maximum segment length, and total available memory to determine the actual number of samples
or segments, and time or points. However, the display of the complete waveform with all its
segments may not entirely fill the screen.
You can also use Sequence mode in remote operation to take full advantage of the instrument's
high data-transfer capability.
86
WM-OM-E Rev I
X-Stream Operator’s Manual
How the instrument captures segments
To Set Up Sequence Mode
1. In the menu bar, touch Timebase, then touch Horizontal Setup... in the drop-down menu.
2. Touch the Smart Memory tab, then touch the Sequence mode button
.
3. Under Sequence Options, touch inside the Num Segments data entry field and enter the
number of segments you want to display, using the pop-up keypad.
4. Touch inside the Timeout data entry field and enter a timeout value.
Note: The timeout period accounts for instances when a Num Segments miscount occurs for some reason and the scope
waits indefinitely for an unforthcoming segment. During that time, no scope functions are accessible. By means of a timeout
value, however, the acquisition will be completed, the waveform displayed, and control of the scope returned to the user
after the timeout has elapsed.
5. Touch the Enable Timeout checkbox.
6. In the menu bar, touch Display, then Display Setup... in the drop-down menu.
7. At the far right of the "Display" dialog, touch inside the Display mode field, and make a
selection from the pop-up menu.
8. Touch inside the Num seg displayed field and enter a value from 1 to 80, using the pop-up
numeric keypad.
WM-OM-E Rev I
87
9. Touch inside the Starting at field and enter a starting segment number, using the pop-up
numeric keypad.
Sequence Display Modes
The instrument gives you a choice of five ways to display your segments:
88
y
Adjacent
y
Waterfall (cascaded)
y
Mosaic (tiled)
y
Overlay
y
Perspective
WM-OM-E Rev I
X-Stream Operator’s Manual
The number of segments you choose to display (80 maximum) can be less than the total number of
segments in the waveform. For example, in the pop-up images above, the number of display
segments is 10, but the total number of segments entered in the timebase dialog's Num Segments
field is 100.
To Display Individual Segments
1. Touch Math in the menu bar, then Math Setup... in the drop-down menu.
2. Touch a function tab (F1 to Fx The number of math traces available depends on the
software options loaded on your scope. See specifications.).
3. Touch inside the Operator1 field and select Segment
from the pop-up menu.
4. In the right-hand dialog, touch the Select tab.
5. Touch inside the Select data entry field and use the pop-up numeric keypad to select the
segment you want to display.
Note: In Persistence mode, the segments are automatically overlaid one on top of the other in the display. In
non-Persistence mode, they appear separately on the grid.
To View Time Stamps
1. In the menu bar, touch Timebase, then touch Acquisition Status... in the drop-down
menu.
2. Touch the Time tab.
3. Touch one of the channel buttons under Select Waveform.
4. Touch inside the Select Segment field and enter a segment number, using the pop-up
keypad.
WM-OM-E Rev I
89
RIS Sampling Mode -- For Higher Sample Rates
RIS (Random Interleaved Sampling) is an acquisition technique that allows effective sampling rates
higher than the maximum single-shot sampling rate. It is used on repetitive waveforms with a stable
trigger. The maximum effective sampling rate of 50 GS/s can be achieved with RIS by making 100
single-shot acquisitions at 500 MS/s. The bins thus acquired are positioned approximately 20 ps
apart. The process of acquiring these bins and satisfying the time constraint is a random one. The
relative time between ADC sampling instants and the event trigger provides the necessary variation,
measured by the timebase to 5 ps resolution.
The instrument requires multiple triggers to complete an acquisition. The number depends on the
sample rate: the higher the sample rate, the more triggers are required. It then interleaves these
segments (see figure) to provide a waveform covering a time interval that is a multiple of the
maximum single-shot sampling rate. However, the real-time interval over which the instrument
collects the waveform data is much longer, and depends on the trigger rate and the amount of
interleaving required. The oscilloscope is capable of acquiring approximately 40,000 RIS segments
per second.
Note: RIS mode is not available when the scope is operating in Fixed Sample Rate mode.
When the SDA 11000 is operating in 11 GHz mode, RIS mode sampling is not available.
90
WM-OM-E Rev I
X-Stream Operator’s Manual
Roll Mode
Roll mode applies only to WavePro 7000A and WaveRunner 6000A series scopes. It is invoked
automatically when the time per division is 500 ms/div or greater. However, you can cancel Roll
Mode and return to Real Time mode at any time.
Roll mode displays, in real time, incoming points in single-shot acquisitions that have a sufficiently
low data rate. The oscilloscope rolls the incoming data continuously across the screen until a
trigger event is detected and the acquisition is complete. The parameters or math functions
connected to each channel are updated every time the roll mode buffer is updated, as if new data is
available. This resets statistics on every step of Roll mode that is valid because of new data.
Note: If the processing time is greater than the acquire time, the data in memory gets overwritten. In this case, the
instrument issues the warning: Channel data is not continuous in ROLL mode!!! and rolling will start over again.
WM-OM-E Rev I
91
VERTICAL SETTINGS AND CHANNEL CONTROLS
Adjusting Sensitivity and Position
To Adjust Sensitivity
1. Press the appropriate channel push button, for example
to turn on channel 1. Or
touch Vertical in the menu bar, then Channel 1 in the drop-down menu.
2. Touch inside the Trace On checkbox to display the trace.
for the selected channel. Or you can touch
3. Turn the volts per division knob
inside the Volts/Div field and type in a value using the pop-up keypad, or use the up/down
arrows.
4. The voltage that you set is displayed in the trace descriptor label
the Volts/Div field.
and in
To Adjust the Waveform's Position
Turn the vertical offset adjust knob directly above the channel button whose waveform you want to
move vertically. Or you can touch inside the Offset field and type in a value on the pop-up keypad.
To set the vertical offset to zero, touch the Zero Offset button directly below the Offset field.
Coupling
The choices of coupling are as follows:
•
DC 50 ohms (all instruments)
•
GROUND (all instruments)
•
DC 1 Mohms (WavePro & WaveRunner instruments)
•
AC 1 Mohms (WavePro & WaveRunner instruments)
Overload Protection
The maximum input voltage is 4 V peak. Whenever the voltage exceeds this limit, the coupling
mode automatically switches from DC 50 ohms to GROUND. You will then have to manually reset
the coupling to DC 50 ohms, as described next.
To Set Coupling
1. In the menu bar, touch the Vertical button, then Channel X Setup... in the drop-down
menu.
92
WM-OM-E Rev I
X-Stream Operator’s Manual
2. Touch inside the Coupling field and select a coupling mode from the pop-up menu.
Probe Attenuation
To Set Probe Attenuation
LeCroy's ProBus® system automatically senses probes and sets their attenuation for you. If you
want to set the attenuation manually,
1. In the menu bar, touch Vertical, then select a channel from the drop-down menu.
. Touch a divide-by menu
2. Touch inside the Probe Atten. data entry field
selection or touch Var (variable). If you choose Var, type in a value using the pop-up
numeric keypad.
Bandwidth Limit
Reducing the bandwidth also reduces the signal and system noise, and prevents high frequency
aliasing.
To Set Bandwidth Limiting
To set bandwidth limiting
1. In the menu bar, touch Vertical, then select a channel from the drop-down menu.
2. Touch inside the Bandwidth field and select a bandwidth limit value from the pop-up menu.
The options are
•
•
•
•
•
•
Full (all X-Stream scopes)
4 GHz (WaveMaster 8600A/8500A, DDA-5005A, SDA)
3 GHz (WaveMaster 8600A/8500A/8400A/8420, DDA-5005A, SDA)
1 GHz (WaveMaster Scopes, DDA-5005A, SDA)
200 MHz (all X-Stream scopes)
20 MHz (all X-Stream scopes)
Linear and (SinX)/X Interpolation
Linear interpolation, which inserts a straight line between sample points, is best used to reconstruct
straight-edged signals such as square waves. (Sinx)/x interpolation, on the other hand, is suitable
for reconstructing curved or irregular waveshapes, especially when the sample rate is 3 to 5 times
the system bandwidth.
To Set Up Interpolation
1. Touch the button for the channel you want to set up,
for example.
2. In the dialog area, touch inside the Interpolation data entry field under Pre-Processing.
"Pre-Processing" means before Math processing.
3. Touch inside the Interpolation data entry field. A pop-up menu appears offering Linear or
WM-OM-E Rev I
93
Sinx/x interpolation.
4. Touch the button for the type of interpolation you want.
Inverting Waveforms
Touch the Invert checkbox to invert the waveform for the selected channel.
QuickZoom
QuickZoom automatically displays a zoom of the channel or trace on a new grid.
To Turn On a Zoom
Touch the Zoom button
in the channel dialog.
Finding Scale
You can access the Find Scale button from the channel setup dialog. This feature automatically
calculates peak-to-peak voltage, and chooses an appropriate Volts/Div scale to fully display the
waveform.
To Use Find Scale
1. Touch the trace label for the waveform you desire.
2. Touch the Find Scale icon.
Variable Gain
Variable Gain lets you change the granularity with which the gain is incremented. For example,
when Variable Gain is disabled, the gain will increase or decrease in preset increments of 10 or
100 mV each time you touch the Up/Down buttons.
However, when Variable Gain is enabled, you can increase or decrease the gain in increments as
small as 1 mV, depending on the scale of the waveform.
To Enable Variable Gain
1. Touch the descriptor label for the waveform whose gain you want to vary.
2. Touch the Variable Gain check box.
Channel Deskew
Unlike the Deskew math function, channel Deskew does no resampling, but instead adjusts the
horizontal offset by the amount that you enter. The valid range is dependent on the current
timebase +/- 9 divisions.
To Set Up Channel Deskew
1. In the menu bar, touch Vertical; from the drop-down menu, select a channel to set up.
2. Touch inside the Deskew data entry field and enter a value using the pop-up numeric
keypad.
94
WM-OM-E Rev I
X-Stream Operator’s Manual
TIMEBASE AND ACQUISITION SYSTEM
Timebase Setup and Control
Set up the timebase by using the front panel Horizontal controls, just as for analog scopes. For
additional timebase setups
1. Touch Timebase in the menu bar, then Horizontal Setup... in the drop-down menu. The
"Horizontal" dialog appears.
2. Touch inside the Time/Division data entry field and enter a value using the pop-up
numeric keypad, or use the up/down arrows to adjust the value.
3. Touch inside the Delay data entry field and type in a value, using the pop-up keypad.
Touch the Set To Zero button to set the delay to zero.
4. Touch the SMART Memory button or tab and adjust the memory as needed.
Autosetup
When channels are turned on, Autosetup operates only on those turned-on channels. If no
channels are turned on, all channels are affected. When more than one channel is turned on, the
first channel in numerical order with a signal applied to it is automatically set up for edge triggering.
You can perform an autosetup of all these functions together by simply pressing
panel, or by touching Autosetup
drop-down menu.
on the front
in the Vertical, Timebase, or Trigger
Dual Channel Acquisition
Combining of Channels
Note: Does not apply to SDA 11000.
Channels can be combined to increase sample rate, memory, or both in order to capture and view
a signal in all its detail. When you combine channels, uncombined channels like EXT BNC remain
available for triggering, even though they are not displayed.
In 2-channel operation, channels 2 and 3 are active. In Auto operation, you can use channel 1 or 2,
and channel 3 or 4. On the paired channels the maximum sampling rate is doubled and the record
length is greatly increased:
Ch 1 & Ch 3
20 GS/s
Ch 1 & Ch 4
20 GS/s
Ch 2 & Ch 3
20 GS/s
Ch 2 & Ch 4
20 GS/s
As you can see, sampling can be maximized to 20 GS/s for any combination of two channels,
WM-OM-E Rev I
95
except a combination of channels 1 and 2, or channels 3 and 4, which yield 10 GS/s. The basic rule
is to choose either channel 1 or 2 for your first input, and either channel 3 or 4 for the second input.
Refer to Acquisition Modes in the specifications for maximum sample rates.
To Combine Channels
1. In the menu bar, touch Timebase; the "Horizontal" setup dialog opens.
2. Under Active Channels, touch 4, 2 or Auto. The maximum sample rate is shown
alongside each button.
SDA 11000 DBI Controls
The SDA 11000 scope’s 11 GHz bandwidth and 40 GS/s sampling rate are achieved by an
innovative LeCroy technology called Digital Bandwidth Interleaving (DBI). This technology allows
resources to be borrowed from unused channels to multiply not only sample rate but also
bandwidth.
When 11 GHz is selected, the active channels are either C2 or C3
or both, providing 40 GS/s sampling on each channel. For 6 GHz
bandwidth, all four channels can be used, providing 20 GS/s
sampling on each channel. Channels can be set to allow 11 GHz
and 6 GHz bandwidths at the same time, as shown at left.
Bandwidth
Number of
Channels
Sample Rate
11 GHz
2
40 GHz
6 GHz
4
20 GHz
SMART Memory
Note: When the SDA 11000 is in 11 GHz mode, only Fixed Sample Rate sampling is available.
LeCroy's SMART Memory feature ensures the highest time resolution for the time window
displayed, without aliasing. SMART Memory provides these advantages:
•
Acquisition memory is automatically allocated as needed.
•
Memory size optimization: Set Maximum Memory optimizes memory to obtain highest
sampling rate, reducing the risk of aliasing. You can set a maximum memory up to 48
Mpts.
•
Fixed Sample Rate allows setting of a specific sample rate, with the scope calculating
the amount of memory needed for a timebase setting.
•
The entire acquisition is displayed on the screen.
•
High-speed compaction shows all significant features of your waveform.
You can set a maximum memory up to 48 Mpts.
96
WM-OM-E Rev I
X-Stream Operator’s Manual
To Set Up SMART Memory
1. Touch Timebase in the menu bar, then SMART Mem Setup... in the drop-down menu.
2. Touch the SMART Memory tab.
3. Under Timebase Mode, touch the Set Maximum Memory or Fixed Sample Rate button.
Information about your choice appears below the buttons. The calculated memory length
and time per sample point appear below the scroll buttons.
4. Touch inside the Time/Division data entry field and set a time per division.
Note: If you are currently acquiring waveforms, you will notice a change in sampling rate as you select different modes.
5. If you selected Sequence mode, touch inside the Num Segments data entry field and
enter a value using the pop-up numeric keypad. If you want to use a timeout period, touch
the Enable Timeout checkbox; then touch inside the Timeout data entry field and enter a
value.
WM-OM-E Rev I
97
TRIGGERING
Trigger Setup Considerations
Trigger Modes
Auto mode causes the scope to sweep even without a trigger. An internal timer triggers the sweep
so that the display remains, even when the signal does not cause a trigger.
In Normal mode, the scope sweeps only if the input signal reaches the set trigger point. Otherwise
it continues to display the last acquired waveform.
In Single mode, only one sweep occurs each time you press the button.
Stop mode inhibits all sweeps until you select one of the other three modes.
Trigger Types
The triggers available to you are defined as follows:
A simple trigger, Edge trigger is activated by basic waveform features or conditions such
as positive or negative slope, and holdoff.
One of LeCroy's SMART Triggers®, Width trigger allows you to define a positive- or
negative-going pulse width bounded by a voltage level, above or below which a trigger
will occur. Or you can specify a pulse width and voltage range, within or outside of which
a trigger will occur.
Another of the SMART Triggers, Glitch trigger is a simpler form of Width trigger. Use
Glitch trigger when you want to define a fixed pulse-width time or time range only. Glitch
trigger makes no provision for voltage levels or ranges.
While Glitch trigger performs over the width of a pulse, Interval trigger performs over the
width of an interval the signal duration (the period) separating two consecutive edges of
the same polarity: positive to positive or negative to negative. Use interval trigger to
capture intervals that fall short of, or exceed, a given time limit. In addition, you can define
a width range to capture any interval that is itself inside or outside the specified range an
Exclusion trigger by interval.
The Qualify trigger is an edge-qualified SMART Trigger that allows you to use one
signal's positive or negative transition to qualify a second signal, which is the trigger
source. For Qualify trigger, you specify the time or number of events after the transition
when you want the trigger to occur.
The State trigger is a level-qualified SMART Trigger which requires that the qualifying
signal remain above or below a specified voltage level for a trigger to occur. For Sate
trigger, you specify the time or number of events after the signal has gone above or below
the voltage level when you want the trigger to occur.
98
WM-OM-E Rev I
X-Stream Operator’s Manual
Used primarily in single-shot applications, and usually with a pre-trigger delay, Dropout
trigger can detect lost signals. The trigger is generated at the end of the timeout period
following the last trigger source transition. You can select a timeout period from 2 ns to 20
s.
Logic trigger enables triggering on a logical combination (pattern) of five inputs: CH1,
CH2, CH3, CH4, EXT. You have a choice of four Boolean operators (AND, NAND, OR,
NOR), and you can stipulate the high or low voltage logic level for each input
independently.
Determining Trigger Level, Slope, Source, and Coupling
Level defines the source voltage at which the trigger circuit will generate an event: a change in the
input signal that satisfies the trigger conditions. The selected trigger level is associated with the
chosen trigger source.
Trigger level is specified in volts and normally remains unchanged when you change the vertical
gain or offset. The amplitude and range of the trigger level are limited as follows:
•
+/-5 screen divisions with a channel as the trigger source
•
+/-400 mV with EXT as the trigger source
•
+/-4 V with EXT/10 as the trigger source
•
+/-40 mV with EXT*10 as the trigger source
•
None with LINE as the trigger source (zero crossing is used).
Coupling refers to the type of signal coupling at the input of the trigger circuit. Because of the
instrument's very high bandwidth, there is only one choice of trigger coupling: DC 50 ohms.
However, as a visual check of where ground is, you may switch the channel to ground coupling at
any time while testing.
With DC coupling, all of the signal's frequency components are coupled to the trigger circuit for
high-frequency bursts.
Slope determines the direction of the trigger voltage transition used for generating a particular
trigger event. You can choose a positive or negative slope. Like coupling, the selected slope is
associated with the chosen trigger source.
WM-OM-E Rev I
99
Edge trigger works on the selected edge at the chosen level. The slope (positive or negative) is specified in the
Trigger label permanently displayed below-right of the grid.
Trigger Source
The Trigger On source may be one of the following:
•
The acquisition channel signal (CH 1, CH 2, CH 3 or CH 4) conditioned for the overall
voltage gain, coupling, and bandwidth.
•
The line voltage that powers the oscilloscope (LINE). This can be used to provide a
stable display of signals synchronous with the power line. Coupling and level are not
relevant for this selection.
•
The signal applied to the EXT BNC connector (EXT). This can be used to trigger the
oscilloscope within a range of +/-400 mV on EXT, +/-4 V with EXT/10 as the trigger
source, or +/-40 mV with EXT*10 as the trigger source.
•
A logic pattern.
Level
Level defines the source voltage at which the trigger circuit will generate an event (a change in the
input signal that satisfies the trigger conditions). The selected trigger level is associated with the
chosen trigger source. Note that the trigger level is specified in volts and normally remains
unchanged when the vertical gain or offset is modified.
The Amplitude and Range of the trigger level are limited as follows:
•
+/-5 screen divisions with a channel as the trigger source
•
+/-400 mV with EXT as the trigger source
•
+/-4 V with EXT/10 as the trigger source
•
+/-40 mV with EXT*10 as the trigger source
•
none with LINE as the trigger source (zero crossing is used)
Note: Once specified, Trigger Level and Coupling are the only parameters that pass unchanged from trigger mode to trigger
mode for each trigger source.
100
WM-OM-E Rev I
X-Stream Operator’s Manual
Holdoff by Time or Events
Holdoff is an additional condition of Edge trigger. It can be expressed either as a period of time or
an event count. Holdoff disables the trigger circuit for a given period of time or number of events
after the last trigger occurred. Events are the number of occasions on which the trigger condition is
met. The trigger will again occur when the holdoff has elapsed and the trigger's other conditions are
met.
Use holdoff to obtain a stable trigger for repetitive, composite waveforms. For example, if the
number or duration of sub-signals is known you can disable them by choosing an appropriate
holdoff value. Qualified triggers operate using conditions similar to holdoff.
Hold Off by Time
Sometimes you can achieve a stable display of complex, repetitive waveforms by placing a
condition on the time between each successive trigger event. This time would otherwise be limited
only by the input signal, the coupling, and the instrument's bandwidth. Select a positive or negative
slope, and a minimum time between triggers. The trigger is generated when the condition is met
after the selected holdoff time, counted from the last trigger. Any time between 2 ns and 20 s can be
selected. The delay is initialized and started on each trigger.
Edge Trigger with Holdoff by Time. The bold edges on the trigger source indicate that a positive slope has been
selected. The broken upward-pointing arrows indicate potential triggers, which would occur if other conditions are
met. The bold arrows indicate where the triggers actually occur when the holdoff time has been exceeded.
Hold Off by Events
Select a positive or negative slope and a number of events. An event is the number of times the
trigger condition is met after the last trigger. A trigger is generated when the condition is met after
this number, counted from the last trigger. The count is restarted on each trigger. For example, if
the event number is two, the trigger will occur on the third event. From one to 1,000,000,000 events
can be selected.
WM-OM-E Rev I
101
Edge Trigger with Holdoff by Events (in this example, two events). The bold edges on the trigger source indicate
that a positive slope has been selected. The broken, upward-pointing arrows indicate potential triggers, while the
bold ones show where triggers actually occur after the holdoff expires.
Simple Triggers
Edge Trigger on Simple Signals
The instrument uses many waveform capture techniques that trigger on features and conditions
that you define. These triggers fall into two major categories:
•
Edge activated by basic waveform features or conditions such as a positive or
negative slope, and hold-off
•
SMART Trigger® sophisticated triggers that enable you to use basic or complex
conditions for triggering.
Use Edge Triggers for simple signals, and the SMART Triggers for signals with rare features, like
glitches.
Control Edge Triggering
Horizontal: Turn the Delay knob in the HORIZONTAL control group to adjust the trigger's
horizontal position. Or, touch inside the Delay field in the timebase setup dialog and enter a value,
using the pop-up keypad.
The trigger location is shown by a marker below the grid
.
Post-trigger delay is indicated by a left-pointing arrow below-left of the grid
is given in the title line of the TimeBase label
102
. The time value
below-right of the grid.
WM-OM-E Rev I
X-Stream Operator’s Manual
Vertical: Turn the Level knob
vertical threshold.
in the TRIGGER control group to adjust the trigger's
Turn this knob to adjust the level of the trigger source or the highlighted trace. Level defines the
source voltage at which the trigger will generate an event a change in the input signal that satisfies
the trigger conditions.
Alternatively, in the "Trigger" dialog, you can touch inside the Level field and type in a value, using
the pop-up numeric keypad. To quickly set a level of zero volts, touch the Zero Level button directly
below the Coupling field.
An arrow on the left side of the grid shows the threshold position. This arrow is only visible if the
trigger source is displayed.
To Set Up an Edge Trigger
Channel Setup
1. In the menu bar, touch Trigger, then select Trigger Setup... from the drop-down menu.
2. Touch the Edge trigger button
under the Trigger tab.
3. Touch inside the Trigger On data entry field and select an input from the pop-up menu:
4. Touch inside the Level data entry field
. In the pop-up numeric keypad,
to increase or
enter a value in millivolts or use the up/down buttons
decrease the value in increments of 1 mV. Or, touch one of the preset value buttons:
WM-OM-E Rev I
103
Max.
1.000 V
Default
0 mV
Min.
1.000 V
5. Select the holdoff by touching the Time or Events buttons
,
pop-up numeric keypad, enter a value and specify the unit of time:
. Using the
.
Or, use the up/down buttons
to increase or decrease the time value in
increments of 200 ps. Or, touch one of the preset value buttons
104
WM-OM-E Rev I
X-Stream Operator’s Manual
.
The preset Time values are as follows:
Max.
20.0 s
Default
50.0 ns
Min.
2 ns
The preset Events values are as follows:
Max.
1,000,000,000 events
Default
1 event
Min.
1 event
6. Choose Positive or Negative slope:
.
SMART Triggers
Width Trigger
How Width Trigger Works
Width trigger allows you to define a positive- or negative-going pulse width bounded by a voltage
level, above or below which a trigger will occur. You can specify a pulse width and voltage range,
within or outside of which a trigger will occur.
WM-OM-E Rev I
105
To Set Up Width Trigger
1. In the menu bar, touch Trigger, then Trigger Setup... in the drop-down menu.
2. Touch the Width trigger button
3. Touch inside the Trigger On data entry field and select a source on which to trigger:
4. Touch inside the Level data entry field and enter a value using the pop-up numeric keypad.
5. Select positive or negative slope.
6. Touch the LessThan button and enter a pulse-width value in the Upper Limit data entry
field. Or touch the GreaterThan button and enter a pulse-width value in the Lower Limit
to set up a
data entry field. Or touch the InRange button. Touch the Delta button
nominal range, plus or minus a delta value in seconds. Touch inside the Nominal Width
and Delta data entry fields and enter values using the pop-up numeric keypads.
to set up a precise pulse-width range. Touch
Alternatively, touch the Limits button
inside the Lower Limit and Upper Limit data entry fields and enter values using the
pop-up keypads. Or touch the OutOfRange button and perform the same range setups as
for InRange triggering.
Glitch Trigger
How Glitch Trigger Works
Glitch trigger can be used to catch glitches. You can specify a pulse width or a pulse width range.
Pulse smaller than selected pulse width: Set a maximum pulse width. This glitch trigger is
generated on the selected edge (positive or negative) when the pulse width is less than or equal to
the set width.
106
WM-OM-E Rev I
X-Stream Operator’s Manual
The timing for the width is initialized and restarted on the opposite slope to that selected. You can
set widths from 600 ps to 20 s.
NOTE: If the glitch's width is narrower than the signal's width, set the trigger to a narrower width than that of the signal. The
signal's width, as determined by the instrument trigger comparator, depends on the DC trigger level. If that level were to be
set at the middle of a sine wave, for example, the width could then be considered as the half period. But if the level were
higher, the signal's width would be considered to be less than the half period.
Glitch Trigger: In this example triggering on a pulse width less than or equal to the width selected. The broken
upward-pointing arrow indicates a potential trigger, while the bold one shows where the actual trigger occurs.
To Set Up Glitch Trigger
1. In the menu bar, touch Trigger, then Trigger Setup... in the drop-down menu.
2. Touch the Glitch trigger button
.
3. Touch inside the Trigger On data entry field and select a source on which to trigger:
WM-OM-E Rev I
107
4. Touch inside the Level data entry field and enter a value using the pop-up numeric keypad.
5. Select positive or negative slope.
6. Define the width of the glitch you are looking for. You can trigger on any glitch less than a
chosen pulse-width (Upper Limit); or you can trigger on a chosen range (InRange).
Touch the LessThan button; the Upper Limit data entry field alone is displayed. Touch the
InRange button; the Upper Limit and Lower Limit fields are displayed.
7. Touch inside the limit field or fields and enter a time value using the pop-up numeric
keypad.
Interval Trigger
How Interval Triggers Work
While Glitch trigger performs over the width of a pulse, Interval trigger performs over the width of an
interval, with the signal duration (period) separating two consecutive edges of the same polarity:
positive to positive or negative to negative. Use Interval trigger to capture intervals that fall short of,
or exceed, a given time limit. In addition, you can define a width range to capture any interval that is
itself inside or outside the specified range: an exclusion trigger by interval.
Interval Less Than: For this Interval Trigger, generated on a time interval smaller than the one that
you set, choose a maximum interval between two like edges of the same slope (positive, for
example).
The trigger is generated on the second (positive) edge if it occurs within the set interval. The
instrument initializes and restarts the timing for the interval whenever the selected edge occurs.
You can set an interval from 2 ns to 20 s.
108
WM-OM-E Rev I
X-Stream Operator’s Manual
Interval Trigger that triggers when the interval width is smaller than the selected interval. The broken,
upward-pointing arrow indicates a potential trigger, while the bold one shows where the actual trigger occurs on
the positive edge within the selected interval.
Interval Greater Than: For this Interval Trigger, generated on an interval larger than the one that
you set, select a minimum interval between two edges of the same slope. The instrument
generates the trigger on the second edge if it occurs after the set interval. The timing for the interval
is initialized and restarted whenever the selected edge occurs. You can set an interval from 2 ns to
20 s.
WM-OM-E Rev I
109
Interval Trigger that triggers when the interval width is larger than the set interval. The broken upward-pointing
arrow indicates a potential trigger, while the bold one shows where the actual trigger occurs on the positive edge
after the selected interval.
Interval In Range: This Interval Trigger is generated whenever an interval between two edges of
the same slope falls within a selected range. The instrument initializes and restarts the timing for
the interval whenever the selected edge occurs. You can set an interval from 2 ns to 20 s.
110
WM-OM-E Rev I
X-Stream Operator’s Manual
Interval Trigger that triggers when the interval falls within the selected range:
t1 = range's lower time limit; t2 = range's upper limit. The broken upward-pointing arrow indicates a potential
trigger, while the bold one indicates where the actual trigger occurs on the positive edge within the selected
range.
To Set Up Interval Trigger
1. In the menu bar, touch Trigger, then Trigger Setup... in the drop-down menu.
2. Touch the Interval trigger button
3. Touch inside the Trigger On data entry field and select a source on which to trigger:
WM-OM-E Rev I
111
4. Touch inside the Level data entry field and enter a value using the pop-up numeric keypad.
5. Select positive or negative slope.
6. Touch the LessThan button and enter a pulse-width value in the Upper Limit data entry
field.
Or touch the GreaterThan button and enter a value in the Lower Limit data entry field.
Or touch the InRange button.
Touch the Delta button
to set up a nominal range, plus or minus a delta value in
seconds. Touch inside the Nominal Width and Delta data entry fields and enter values
using the pop-up numeric keypads.
to set up a precise range. Touch inside the Lower Limit
Touch the Limits button
and Upper Limit data entry fields and enter values using the pop-up numeric keypads.
Or touch the OutOfRange button and perform the same Delta or Limits setup as for
InRange triggering.
Qualified Trigger
How Qualified Triggers Work
Use a signals transition above or below a given level (its validation) as an enabling (qualifying)
condition for a second signal that is the trigger source. These are Qualified triggers. For Edge
Qualified triggers (the default) the transition is sufficient and no additional requirement is placed on
the first signal. For State Qualified triggers the amplitude of the first signal must remain in the
desired state until the trigger occurs. A qualified trigger can occur immediately after the validation,
or following a predetermined time delay or number of potential trigger events. The time delay or
trigger count is restarted with every validation.
Within Time creates a time window within which a trigger can occur.
Wait Time determines a delay from the start of the desired pattern. After the delay
(timeout) and while the pattern is present, a trigger can occur. The timing for the delay
is restarted when the selected pattern begins.
Events determines a minimum number of events of the trigger source. An event is
generated when a trigger source meets its trigger conditions. On the selected event
of the trigger source and while the pattern is present, a trigger can occur. The count is
initialized and started whenever the selected pattern begins, and continues while the
pattern remains. When the selected count is reached, the trigger occurs.
112
WM-OM-E Rev I
X-Stream Operator’s Manual
Edge Qualified and Wait: Trigger after timeout. The broken upward-pointing arrows indicate potential triggers,
while the bold ones show where the actual triggers occur.
Qualified First Trigger
Qualified First trigger is intended to be used exclusively in Sequence Mode to speed up the trigger
rate. With Qualified First trigger, a single valid trigger is sufficient to acquire a full sequence. Other
than in Sequence Mode, Qualified First is identical to the Qualified triggers.
In data storage applications, the index pulse can be defined as the qualifier signal and the servo
gate signal as the trigger source.
To Set Up an Edge Qualified Trigger
1. In the menu bar, touch Trigger, then Trigger Setup... in the drop-down menu.
2. Touch the Qualify trigger button
3. Touch inside the Trigger On data entry field and select a source on which to trigger:
WM-OM-E Rev I
113
4. Select Positive or Negative slope.
5. Touch inside the After data entry field and select the qualifying signal source from the
pop-up menu. If you select an input channel or external source, touch inside the has gone
data entry field and select a logic level: Above or Below. Then touch inside the Level field
and set a voltage level using the pop-up numeric keypad. If you select Pattern from the
pop-up menu, touch the Pattern tab and choose a logic gate:
.
Then touch inside the State field for each channel input you want to use in the pattern and
select a logic condition: High or Low. Select Don't Care for unused inputs. For the inputs
to be used, touch inside each Level field and enter a voltage threshold using the pop-up
numeric keypad. Then touch the Trigger tab again.
6. If you want to set a holdoff in time or events, touch one of the Qualify by: buttons:
,
,
.
7. Touch inside the field below the Qualify by: buttons and enter a value using the numeric
keypad.
114
WM-OM-E Rev I
X-Stream Operator’s Manual
8. To set up a Qualified First trigger, touch the Qualify first segment only checkbox if you
are in Sequence mode.
State Trigger
State trigger is another Qualified trigger; however, instead of using the edges of the qualifying
inputs, State trigger uses the logic state of the inputs to qualify the trigger. Therefore, the pattern
must become true and remain true (for a period of time or number of events that you specify) to
qualify the trigger.
See also “How Qualified Triggers Work.”
State Qualified and Wait: Trigger after timeout. The broken upward-pointing arrows indicate potential triggers,
while the bold arrows show where the actual triggers occur.
To Set Up a State Qualified Trigger
1. In the menu bar, touch Trigger, then Trigger Setup... in the drop-down menu.
2. Touch the State trigger button
3. Touch inside the Trigger On data entry field and select a source on which to trigger
WM-OM-E Rev I
115
4. Select Positive or Negative slope.
5. Touch inside the has gone data entry field and select the qualifying signal source from the
pop-up menu. If you select an input channel or external source, touch inside the has gone
data entry field and select a logic level: Above or Below. Then touch inside the Level field
and set a voltage level using the pop-up numeric keypad. If you want to set a holdoff in time
or events, touch one of the holdoff buttons:
,
,
.
6. Touch inside the field below the holdoff buttons and set a value using the numeric keypad.
Dropout Trigger
Used primarily in single-shot applications, and usually with a pre-trigger delay, Dropout trigger can
detect lost signals. The trigger is generated at the end of the timeout period following the last trigger
source transition. You can set a timeout period from 2 ns to 20 s.
116
WM-OM-E Rev I
X-Stream Operator’s Manual
How Dropout Trigger Works
Dropout Trigger: occurs when the timeout has expired. The bold upward-pointing arrows show where the trigger
occurs.
To Set Up Dropout Trigger
1. In the menu bar, touch Trigger, then Trigger Setup... in the drop-down menu.
2. Touch the Dropout trigger button
.
3. Select Positive or Negative slope.
4. Touch inside the Trigger after timeout data entry field and enter a time window using the
pop-up numeric keypad.
Logic Trigger
How Logic Trigger Works
Logic Trigger enables triggering on a logical combination of up to five inputs: CH 1, CH 2, CH 3, CH
4, and EXT. The combination of inputs is referred to as a pattern. There are four logic gates
available: AND, NAND, OR, NOR.
A trigger state is either high or low: high when a trigger source is greater than the trigger level
(threshold) and low when less than it. For example, an AND pattern could be defined as true when
the trigger state for CH 1 is high, CH 2 is low, and EXT is irrelevant (X or don't care). If any one of
these conditions is not met, the pattern state is considered false. You can set holdoff limits from 2
ns to 20 s or from 1 to 1,000,000,000 events.
WM-OM-E Rev I
117
Logic Applications
Logic Trigger can be used in digital design for the testing of complex logic inputs or data transmission buses.
To Set Up Logic Trigger
1. In the menu bar, touch Trigger, then Trigger Setup... in the drop-down menu.
2. Touch the Logic trigger button
.
3. Touch the Pattern tab.
4. For each input you want to include in the logic pattern, touch inside the State data entry
field and select a logic state: Low or High. Select Don't Care for all other inputs.
5. Touch inside the Level data entry field for each input included in the pattern and enter a
voltage level threshold using the pop-up numeric keypad.
6. Touch the Trigger tab.
7. If you want to hold off the trigger (either in time or events) when the pattern becomes true,
touch one of the holdoff buttons
,
.
8. Touch inside the holdoff data entry field and enter a value using the pop-up numeric
keypad.
118
WM-OM-E Rev I
X-Stream Operator’s Manual
Serial Trigger
Serial Trigger is available on SDA “A” model scopes only.
Aux Input Trigger
Some instrument models give you the capability to trigger on an auxiliary input. When you select
this option, the auxiliary trigger setup is routed to channel 3, and an information icon appears in the
Channel 3 descriptor label:
CAUTION
If you select Aux Input trigger on a WavePro 7000A Series scope, but do not input an
external signal, the scope will not operate.
To Set Up Aux Input
1. Touch Trigger in the menu bar, then Trigger Setup... in the drop-down menu.
2. Touch inside the View AUX IN on Channel 3 checkbox
Coupling field will become disabled.
. The
3. Press the Channel 3 front panel button to turn on Channel 3 and display the setup dialog.
4. Perform vertical setups for your auxiliary input in the Channel 3 dialog.
5. Touch Vertical in the menu bar, then Channels Status... in the drop-down menu to view a
summary of the Aux Input setup:
WM-OM-E Rev I
119
DISPLAY FORMATS
Display Setup
1. In the menu bar, touch Display; then touch Display Setup in the drop-down menu.
2. Touch one of the Grid combination buttons:
.
Autogrid automatically adds or deletes grids as you select more or fewer waveforms to
display.
3. Touch inside the grid Intensity data entry field
to 100 using the pop-up keypad.
and enter a value from 0
4. Touch the Grid on top checkbox if you want to superimpose the grid over the waveform.
Depending on the grid intensity, some of your waveform may be hidden from view when the
grid is placed on top. To undo, simply uncheck Grid on top.
5. Touch the Axis labels checkbox to permanently display the values of the top and bottom
grid lines (calculated from volts/div) and the extreme left and right grid lines (calculated
from the timebase).
6. Choose a line style for your trace: solid Line
or Points
.
Sequence Mode Display
To a set up Sequence Mode display, you must first have selected Sequence trigger mode in the
Timebase "Horizontal" dialog. You must also have entered a Num Segments value.
1. In the menu bar, touch Display; then touch Display Setup in the drop-down menu.
2. Touch inside the Display Mode field and select a display mode from the pop-up menu.
120
WM-OM-E Rev I
X-Stream Operator’s Manual
3. Touch inside the Num seg displayed field and enter a value, using the pop-up keypad.
The maximum number of segments that can be displayed is 80.
4. Touch inside the Starting at field and enter a value.
Note: The maximum value that you can enter for Starting at depends on the Num Segments value you entered in the
"Timebase" dialog. It also depends on the Num seg displayed value you entered here in the "Display" dialog. For example,
if you had entered a value of 500 in Num Segments, and a value of 10 in Num seg displayed, the maximum value you can
enter as a starting segment is 491so that 10 segments can be seen.
Persistence Setup
The analog Persistence feature helps you display your waveform and reveal its idiosyncrasies or
anomalies for a repetitive signal. Use Persistence to accumulate on-screen points from many
acquisitions to see your signal change over time. The instrument persistence modes show the most
frequent signal path "three-dimensionally" in intensities of the same color, or graded in a spectrum
of colors.
You can show persistence for up to eight inputs for any channel, math function, or memory location
(M1 to M4).
Saturation Level
The Persistence display is generated by repeated sampling of the amplitudes of events over time,
and the accumulation of the sampled data into "3-dimensional" display maps. These maps create
an analog-style display. User-definable persistence duration can be used to view how the maps
evolve proportionally over time. Statistical integrity is preserved because the duration (decay) is
proportional to the persistence population for each amplitude or time combination in the data. In
addition, the instrument gives you post-acquisition saturation control for a more detailed display.
When you select
mode from the Persistence dialog (with All Locked selected), each
channel is assigned a single color. As a persistence data map develops, different intensities of that
color are assigned to the range between a minimum and a maximum population. The maximum
population automatically gets the highest intensity, the minimum population gets the lowest
intensity, and intermediate populations get intensities in between these extremes.
The information in the lower populations (for example, down at the noise level) could be of greater
interest to you than the rest. The Analog persistence view highlights the distribution of data so that
you can examine it in detail.
You can select a saturation level as a percentage of the maximum population. All populations
above the saturation population are then assigned the highest color intensity: that is, they are
saturated. At the same time, all populations below the saturation level are assigned the remaining
intensities. Data populations are dynamically updated as data from new acquisitions is
accumulated.
WM-OM-E Rev I
121
Color mode persistence, selected by touching
, works on the same principle as the Analog
persistence feature, but instead uses the entire color spectrum to map signal intensity: violet for
minimum population, red for maximum population. A saturation level of 100% spreads the intensity
variation across the entire distribution; at lower saturation levels the intensity will saturate (become
the brightest color) at the percentage value specified. Lowering this percentage causes the pixels
to be saturated at a lower population, and makes visible those rarely hit pixels not seen at higher
percentages.
3-Dimensional Persistence
By selecting 3d
, you can create a topographical view of your waveform from a selection of
shadings, textures, and hues. The advantage of the topographical view is that areas of highest and
lowest intensity are shown as peaks and valleys, in addition to color or brightness. The shape of the
peaks (pointed or flat) can reveal further information about the frequency of occurrences in your
waveform.
The instrument also gives you the ability to turn the X and Y axes of the waveform through 180° of
rotation from -90° to +90°.
Here is an example of a 3-dimensional view of a
square wave using the solid view of color-graded
persistence. Saturation is set at 50%, with red
areas indicating highest intensity. The X-axis has
been rotated 60%; the Y-axis has been rotated
15%.
122
WM-OM-E Rev I
X-Stream Operator’s Manual
Here is a monochrome (analog) view of the same
waveform. The lightest areas indicate highest
intensity, corresponding to the red areas in the
solid view.
Here is a shaded (projected light) view of the same
waveform. This view emphasizes the shape of the
pulses.
Here is a wire frame view of the same waveform in
which lines of equal intensity are used to construct
the persistence map.
Show Last Trace
For most applications, you may not want to show the last trace because it will be superimposed on
top of your persistence display. In those cases turn off Show Last Trace by touching the checkbox.
However, if you are doing mask testing and want to see where the last trace is falling, turn Show
Last Trace on.
WM-OM-E Rev I
123
Persistence Time
You can control the duration of persistence by setting a time limit, in seconds, after which
persistence data will be erased: 0.5 s, 1 s, 2 s, 5 s, 10 s, 20 s, or infinity.
Locking of Traces
The instrument gives you the choice of constraining all input channels to the same mode, saturation
level, persistence time, and last trace display, or setting these for each input channel individually.
Choose
channels individually.
to constrain input channels. Choose
to set up input
To Set Up Persistence
1. In the menu bar touch Display, then touch Persistence Setup... in the drop-down menu.
2. Touch the Persistence On checkbox. If Per Trace is selected, touch the Reset All button
to return all input channel setups to their default settings.
3. Touch the All Locked button if you want to set the same mode, saturation level,
persistence time, and last trace display for all input channels. Touch the Per Trace button
to set these for each input channel individually.
A. If you selected All Locked, touch one of the mode buttons
.
B. Then touch the Show last trace checkbox if you want the last trace displayed.
C. Touch inside the Saturation data entry field and enter a whole number integer,
using the pop-up numeric keypad.
D. Touch inside the Persistence time data entry field and make a selection from the
pop-up menu.
4. If you selected Per Trace, for each input channel touch its tab, then make selections of
mode, saturation level, persistence time, and last trace display in the same way as for All
Locked.
5. To create a 3-dimensional view, touch the 3d button
. Then
A. Touch inside the Saturation data entry field and enter a whole number integer,
using the pop-up numeric keypad.
B. Touch inside the Persistence time data entry field and make a selection from the
pop-up menu.
124
WM-OM-E Rev I
X-Stream Operator’s Manual
C. Under "3D settings," touch inside the Quality field and select an image quality from
the pop-up menu: wire frame, solid, or shaded.
D. For each axis, touch inside the data entry field and enter a value from -90° to +90°.
6. To turn off persistence for an individual channel, touch the left-most persistence mode
. To turn off persistence for all channels, press the
button
front panel Analog Persist button
off.
. This button toggles Analog Persistence on and
Screen Saver
The Windows screen saver is activated in the same way as for any PC.
1. Minimize the instrument display by touching File in the menu bar, then Minimize in the
drop-down menu.
2. Touch Start down in the task bar.
3. Touch Settings in the pop-up menu.
4. Touch Control Panel.
5. Touch Display.
6. Touch the Screen Saver tab.
Moving Traces from Grid to Grid
You can move traces from grid to grid at the touch of a button.
To Move a Channel or Math Trace
1. Touch the descriptor label for the waveform that you want to move.
Example Trace Label
2. Touch the Next Grid button
.
Note: If you have more than one waveform displayed on only one grid, a second grid will open automatically when you
select Next Grid.
WM-OM-E Rev I
125
Zooming Waveforms
The Zoom button
appears as a standard button at the bottom of the channel "Cx
Vertical Adjust" setup dialog if you want to create a math function zoom trace of your input
waveform. On the other hand, you can zoom a memory or math function non-zoom trace directly
without having to create a separate zoom trace. For such traces, a zoom control mini-dialog is
provided at the right of each math trace "Fx" setup dialog:
The front panel "QuickZoom" button
channel.
creates multiple zooms, one for each displayed input
At any time, you can also zoom a portion of a waveform by touching and dragging a rectangle
around any part of the input waveform. The zoom trace will size itself to fit the full width of the grid.
The degree of magnification, therefore, will depend on the size of the rectangle that you create.
When you zoom a waveform, an approximation of the zoomed area will appear in a thumbnail icon
in the "Zoom" dialog:
.
The "Zoom" dialog appears alongside the math setup dialog when Zoom is the math or memory
function selected.
To Zoom a Single Channel
1. In the menu bar, touch Vertical; then touch a channel number in the drop-down menu.
Alternatively, you can just touch the channel trace label for a displayed channel:
126
WM-OM-E Rev I
X-Stream Operator’s Manual
at the bottom of the "Cx Vertical Adjust dialog." A zoom math trace
2. Touch
(one of F5 to Fx) will be created of the selected channel.
3. To vary the degree of zoom, touch the newly created Fx trace label. The setup dialog for
the math function opens, and the zoom control dialog appears at lower-right. It shows the
current horizontal and vertical zoom factors.
4. If you want to increase or decrease your horizontal or vertical zoom in small increments,
touch the Var. checkbox to enable variable zooming. Now with each touch of the zoom
control buttons
, the degree of magnification will change by a small
increment. To zoom in or out in large standard increments with each touch of the zoom
control buttons, leave the Var. checkbox unchecked. To set exact horizontal or vertical
zoom factors, touch inside the Horizontal Scale/div data entry field and enter a
time-per-div value, using the pop-up numeric keypad. Then touch inside the Vertical
Scale/div field and enter a voltage value.
5. To reset the zoom to x1 magnification, touch Reset Zoom in the dialog or press the front
panel zoom button
.
To Zoom by Touch-and-Drag
1. Touch and drag a rectangle around any part of an input channel waveform, math trace, or
memory trace. If you have more than one trace displayed, a pop-up "Rectangle Zoom
Wizard" will appear.
2. If more than one trace is displayed, touch the "Source" tab and select a trace to act on.
3. Touch the "Action" tab and select Create a New Zoom Trace. You will be offered the
choice of creating a new zoom trace or modifying the current trace.
4. Touch the Zoom tab and select a math function trace to display the zoom.
5. Turn the front panel Wavepilot position knobs to adjust the vertical and horizontal position
of the zoom:
WM-OM-E Rev I
127
6. Turn the front panel Zoom knobs to control the boundaries of the zoom.
To Zoom Multiple Waveforms Quickly
on the front panel. Math function traces F5 to F8 will be used
Press the QuickZoom button
to create a zoom of each displayed input channel waveform. Each zoom will be displayed in its own
grid.
To Turn Off Zoom
1. Touch the math function trace label for the zoom you want to turn off.
2. Touch the Trace On checkbox to delete the check mark and disable the zoom trace.
Multi-Zoom
The Multi-zoom feature creates time-locked zoom traces for only the waveforms that you choose to
include. The zooms are of the same X-axis section of each waveform. Thus, as you scroll through a
waveform, all included zooms scroll in unison.
To Set Up Multi-zoom
1. In the menu bar, touch Math, then Math Setup... in the drop-down menu.
2. Verify that the math function selected for each Fx position you want to include is zoom. If
you need to change the math function for any Fx position, simply touch the Fx button and
select Zoom from the Select Math Operator menu.
3. Touch the On checkbox to display each zoom you want to include in the multi-zoom.
4. Touch the Multi-Zoom Setup button. The Multi-Zoom dialog opens.
5. Touch the Multi-zoom On checkbox to enable Multi-zoom. Then touch the Include
checkbox for each zoom trace you want to include in the time-locked multi-zoom:
128
WM-OM-E Rev I
X-Stream Operator’s Manual
Here the user has chosen to include only F2 and F3 in the Multi-zoom, even though F4 is
also a zoom function and is also displayed. Thus, the scrolling feature will not affect zoom
F4.
6. Use the Auto-Scroll buttons at the right of the Multi-Zoom dialog to control the zoomed
section of your waveforms:
To Turn Off Multi-Zoom
1. In the menu bar, touch Math, then Math Setup... in the drop-down menu.
2. Touch the Multi-Zoom On checkbox to turn off Multi-zoom.
XY Display
Use XY displays to measure the phase shift between otherwise identical signals. You can display
either voltage on both axes or frequency on both axes. The traces must have the same X-axis. The
shape of the resulting pattern reveals information about phase difference and frequency ratio.
To Set Up XY Displays
1. In the menu bar, touch Display; then touch Display Setup... in the drop-down menu.
2. Choose an XY display by touching one of the XY display mode buttons
WM-OM-E Rev I
129
. You have the choice of showing the two waveforms on just the
XY grid, or you can also show the input waveforms on a single or dual grid.
and select your
3. Touch inside the Input X and Input Y data entry fields
input sources from the pop-up menus. The inputs can be any combination of channels,
math functions, and memory locations.
130
WM-OM-E Rev I
X-Stream Operator’s Manual
SAVE AND RECALL
Saving and Recalling Scope Settings
You can save or recall scope settings to or from hard disk, floppy disk, or LAN location.
To Save Scope Settings
1. In the menu bar, touch File; then touch Save Setup... in the drop-down menu. Or, press
the Save/Recall front panel button, then touch the "Save Setup" tab.
2. To Save To File, touch inside the Save Instrument Settings data entry field and use the
pop-up keyboard to enter the path to the destination folder. Or touch Browse to navigate to
the destination folder. Then touch
below the data entry field.
To save to folder Internal Setups on the scope's hard drive, touch inside a SetupX data
entry field and use the pop-up keyboard to enter a file name. Touch
alongside the
data entry field. The file is deposited in D:\Internal Setups, and the current date is
displayed above the field.
To Recall Scope Settings
1. In the menu bar, touch File; then touch Recall Setup... in the drop-down menu.
2. To Recall From File, touch inside the Recall panels from file data entry field and use the
pop-up keyboard to enter the path to the source folder. Or touch Browse to navigate to the
source folder. Then touch
on the scope's hard drive, touch
. To recall settings from folder D:\ Internal Setups
alongside the file you want to recall.
To Recall Default Settings
1. In the menu bar, touch File; then touch Recall Setup... in the drop-down menu.
2. Touch the button under Recall Default Setup
WM-OM-E Rev I
131
The default settings are as follows:
Vertical
Timebase
Trigger
50 mV/div
50.0 ns/div
DC50 or AC1M (model
dependent), C1, 0 mV trigger
level
0 V offset
5.0 or 10.0 GS/s
(model dependent)
edge trigger
0 s delay
Auto trigger mode
positive edge
Saving Screen Images
You can send images to a hard copy printer or to storage media. Both types of output are done from
the same dialog.
1. In the menu bar, touch Utilities, then Utilities Setup... in the drop-down menu.
2. Touch the Hardcopy tab.
3. Touch the File button.
4. Touch inside the File Format field and select a file type.
5. Under Colors, touch the Use Print Colors checkbox if you want your waveforms to print in
color with a white background. A white background saves printer toner.
6. Touch inside the Directory field and type in the path to the directory where you want the
image stored, using the pop-up keyboard. Or you can touch the browse button and
navigate there.
7. Touch inside the File Name field and type in a name for your image, using the pop-up
keyboard.
8. Under Include On Print, touch the Grid Area Only checkbox if you do not want to include
the dialog area in the image.
9. Touch the Print Now button.
Saving and Recalling Waveforms
Saving Waveforms
1. In the menu bar, touch File; then touch Save Waveform... in the drop-down menu.
2. In the "Save Waveform" dialog, touch the Save To
or
button.
3. Touch inside the Source field and select a source from the pop-up menu. The source can
be any trace; for example, a channel (C1-C4), math function (F1-F4), or a waveform stored
132
WM-OM-E Rev I
X-Stream Operator’s Manual
in memory (M1-M4).
4. Touch inside the Trace Title data entry field if you want to change the default name of your
waveforms. Use the pop-up keyboard to type in the new name.
Note: You can change the name but not the sequence number.
CAUTION
If you use a name that ends in a number instead of a letter, the instrument may truncate the
number. This is because, by design, the first waveform is automatically numbered 0, the
second 1, etc. For example, if you want to use waveform name "XYZ32" but it is not
preceded by waveforms XYZ0 through XYZ31, the waveform will be renumbered with the
next available number in the sequence.
If you need to use a number in your waveform's name, it is recommended that you append
an alpha character at the end of the number : "XYZ32a" for example.
5. If you are saving to file, touch the Data Format field and select a format type from the
pop-up menu:
.
If you select ASCII or Excel, also touch the SubFormat field and select either Time Data
or Time & Ampl. Then touch the Delimiter field and select a delimiter character from the
pop-up menu: comma, space, semicolon, or tab.
6. Touch the Browse button for the Save file in directory field and browse to the location
where you want the file saved. The file name is assigned automatically and is shown below
the field.
7. Touch
.
Auto Save
You can also enable Auto Save from this dialog by touching one of the Auto Save buttons
WM-OM-E Rev I
133
: Wrap (old files overwritten) or Fill (no files
overwritten).
CAUTION
If you select Fill, you can quickly use up all disk space on your hard disk.
Recalling Waveforms
1. In the menu bar, touch File; then touch Recall Waveform... in the drop-down menu.
2. In the "Recall Waveform" dialog, touch the Recall From
or
button.
A.
If you selected Memory, touch inside the Source field and select a memory
location: M1 to M4.
B.
If you selected File, touch inside the Destination field and select a memory
location in which to store the file.
Touch inside the Show only files field and select an area to limit the search to: channels,
math functions, or memory.
Touch inside the Recall files from directory data entry field and enter the path, using
the pop-up keyboard. Or touch the Browse button to navigate to the file.
Touch inside the Next file will be recalled from data entry field and enter the path, using
the pop-up keyboard. Or touch the Browse button to navigate to the file.
3. Touch
.
Disk Utilities
Use the Disk Utilities dialog to delete files or create folders.
To Delete a Single File
1. Touch File in the menu bar, then Disk Utilities... in the drop-down menu.
2. Touch the Delete button
in the "Disk Utilities" dialog.
3. Touch inside the Current folder data entry field and use the pop-up keyboard to enter the
path to the folder that contains the file you want to delete. Or touch the Browse button and
134
WM-OM-E Rev I
X-Stream Operator’s Manual
navigate to the folder.
4. Touch inside the File to be deleted data entry field and use the pop-up keyboard to enter
the name of the file. Or touch the Browse button and navigate to the file.
5. Once you have located the file, touch the Delete File button.
To Delete All Files in a Folder
1. Touch File in the menu bar, then Disk Utilities... in the drop-down menu.
2. Touch the Delete button
in the "Disk Utilities" dialog.
3. Touch inside the Current folder data entry field and use the pop-up keyboard to enter the
path to the folder that contains the file you want to delete. Or touch the Browse button and
navigate to the folder.
4. Once you have located the folder, touch the Empty Folder button.
To Create a Folder
1. Touch File in the menu bar, then Disk Utilities... in the drop-down menu.
2. Touch the Create button
in the "Disk Utilities" dialog.
3. Touch inside the Current folder data entry field and use the pop-up keyboard to enter the
path to the directory you want to create the folder in, and the name of the folder.
4. Touch the Create Folder button.
WM-OM-E Rev I
135
PRINTING AND FILE MANAGEMENT
Print, Plot, or Copy
The instrument gives you the ability to output files to a printer or plotter, to print to file, or to e-mail
your files. Any WindowsXP supported printer is supported by your instrument.
Printing
To Set Up the Printer
1. In the menu bar, touch File, then Print Setup... in the drop-down menu. The Utilities
Hardcopy dialog opens.
2. In the dialog area, touch the Printer icon
.
3. Under Colors, touch the Use Print Colors checkbox if you want the traces printed on a
white background. A white background saves printer toner. (You can change the printer
colors in the Preference dialog;)
4. Touch inside the Select Printer field. From the touch pad pop-up choose the printer you
want to print to. Touch the Properties button to see your printer setup.
5. Touch the icon for the layout Orientation you want: portrait or landscape.
6. Touch the Grid Area Only checkbox if you do not need to print the dialog area and you
only want to show the waveforms and grids.
To Print
You can print in one of three ways:
•
Press the printer button on the front panel:
•
In the menu bar, touch File, then Print in the drop-down menu.
•
Touch the Print Now button in the "Hardcopy" dialog
Adding Printers and Drivers
Note: If you want to add a printer driver, the driver must first be loaded on the scope.
1. In the menu bar, touch File, then Print Setup... in the drop-down menu. The Utilities
Hardcopy dialog opens.
2. In the dialog area, touch the Printer icon
.
3. Touch the Add Printer button. An MS Windows® window with which to add a printer will
open.
4. Touch the Properties button to change printer properties such as number of copies.
136
WM-OM-E Rev I
X-Stream Operator’s Manual
Changing the Default Printer
1. If you want to change the default printer, minimize the instrument application by touching
File in the menu bar, then Minimize in the drop-down menu.
2. Touch the Start button in the task bar at the bottom of the screen.
3. Select Settings, then Printers.
4. Touch the printer you want to set as the default printer, then touch File, Set as Default
Printer.
Managing Files
Use the instrument's utilities to create waveform files on floppy disk, internal hard drive or network
drives. You can copy files from your hard drive to floppy disk. You also can give your files custom
names and create directories for them.
Hard Disk Partitions
The instrument's hard disk is partitioned into drive C: and drive D:. Drive C: contains the Windows
operating system and the instrument application software. Drive D: is intended for data files.
WM-OM-E Rev I
137
100BASE-T ETHERNET CONNECTION
Connecting to a Network
Use the Ethernet connector (item 8 in the rear panel diagram) to connect the instrument to a
network:
Communicating over the Network
The instrument uses Dynamic Host Configuration Protocol (DHCP) as its addressing protocol.
Therefore, there is no factory set IP address.
Windows Setups
If the instrument is to reside within a domain on your LAN, your IS administrator will have to connect
the scope.
Guidelines for Working in Windows
Although the instrument has an open architecture, avoid modifying the Windows operating system,
since this may cause problems for the instrument's user interface. Please follow these
recommendations:
138
•
Do not load any version of Windows not provided by LeCroy. If you load any Windows
XPe service packs from Microsoft, please be advised that LeCroy cannot guarantee
trouble-free operation afterwards.
•
If the instrument powers up in Windows Safe Mode, the touch screen will not function.
You may need a mouse or keyboard to restore normal operation.
•
Avoid modifying Control Panel settings.
•
Do not change the color resolution (24 bit) or screen size (800 x 600 pixel) settings.
•
After you load third-party software applications, if your scope does not work properly
try reloading the instrument software from the CD shipped with the scope. If your
instrument is not equipped with a CD drive, you will need a USB CD-ROM to do this
(not supplied by LeCroy).
•
Do not modify or remove any system fonts; doing so may affect the readability of the
dialogs.
•
Do not change any display properties like Background, Appearance, Effects, or
Settings. Functionality of the scope or screen saver may be affected.
WM-OM-E Rev I
X-Stream Operator’s Manual
•
Do not make any changes to the Windows folder.
•
Do not make any changes to the BIOS settings.
•
Do not make any changes to the Windows power management system.
System Restore
Although the scope creates regularly scheduled restore points automatically, before you install any
hardware or software on your instrument, LeCroy strongly recommends that you manually create a
restore point. The restore point resides on the scopes hard drive, so no external storage medium
(floppy disk, USB memory stick, etc.) is required.
To Create a Restore Point
1. From the File menu, minimize or Window the scope display to reveal the task bar.
2. In the task bar, select Start, Programs, Accessories, System Tools, System Restore.
3. Touch the Create a restore point radio button, then touch Next.
4. In the Restore point description box, indicate what software or hardware is going to be
added after the restore point is created, then touch Next.
5. The restore point will be created and a confirmation message will be displayed.
WM-OM-E Rev I
139
TRACK VIEWS
Creating and Viewing a Trend
1. In the menu bar, touch Measure, then Measure Setup in the drop-down menu.
2. Touch one of parameter tabs P1 through Px.
3. Touch inside the Source1 data entry field and select an input waveform from the pop-up
menu.
4. Touch inside the Measure data entry field and select a parameter from the pop-up menu.
5. Touch the Trend button
at the bottom of the dialog; then, from the Math
selection for Trend menu, select a math function location (F1 to Fx The number of math
traces available depends on the software options loaded on your scope. See
specifications.) to store the Trend display. The Trend will be displayed along with the trace
label for the math function you selected.
6. Touch the newly displayed Trend math function trace label if you want to change any
settings in the Trend dialog:
Creating a Track View
This feature is available in the XMAP option.
1. In the menu bar, touch Measure, then Measure Setup in the drop-down menu.
2. Touch one of parameter tabs P1 through Px.
3. Touch inside the Source1 data entry field and select an input waveform from the pop-up
menu.
140
WM-OM-E Rev I
X-Stream Operator’s Manual
4. Touch inside the Measure data entry field and select a parameter from the pop-up menu.
at the bottom of the dialog; then, from the Math
5. Touch the Track button
selection for Track menu, select a math function location (F1 to Fx) to store the Track
display. The Track will be displayed along with the trace label for the math function you
selected:
6. Touch the newly displayed Track math function trace label if you want to change any
settings in the Track dialog:
WM-OM-E Rev I
141
HISTOGRAMS
Creating and Viewing a Histogram
Note: The number of sweeps comprising the histogram will be displayed in the bottom line of the trace descriptor label:
To Set Up a Single Parameter Histogram
From Measure Dialog
1. In the menu bar, touch Measure, then Measure Setup.
2. Touch the My Measure button.
3. Touch one of tabs P1 through Px.
4. Touch inside the Source1 field and select an input waveform from the pop-up menu.
5. Touch inside the Measure field and select a parameter from the pop-up menu.
6. Touch the Histogram button at the bottom of the dialog.
7. Touch a math trace in which to place the resulting histogram, then close the pop-up menu.
8. Touch the math trace label for the math trace you just created.
9. In the dialog to the right, touch the Histogram tab.
10. Under "Buffer," touch inside the #Values data entry field and enter a value.
11. Under "Scaling," touch inside the #Bins data entry field and enter a value from 20 to 2000.
12. Touch the Find Center and Width button to center the histogram. Or touch inside the
Center, then the Width, data entry fields and enter a value using the pop-up numeric
keypad.
From Math Dialog
1. In the menu bar, touch Math, then Math Setup.
2. Touch one of function tabs F1 through Fx The number of math traces available depends on
the software options loaded on your scope. See specifications..
3. Touch the Graph button
.
4. Touch inside the Source1 field and select a source from the pop-up menu.
5. Touch inside the Measurement field and select a parameter from the pop-up menu.
6. Touch inside the Graph with field and select Histogram from the pop-up menu.
7. In the dialog to the right, touch the Histogram tab.
142
WM-OM-E Rev I
X-Stream Operator’s Manual
8. Under "Buffer," touch inside the #Values data entry field and enter a value from 20 to 1000.
9. Under "Scaling," touch inside the #Bins data entry field and enter a value from 20 to 2000.
10. Touch the Find Center and Width button to center the histogram. Or touch inside the
Center, then the Width, data entry fields and enter a value using the pop-up numeric
keypad.
11. Touch inside the Vertical Scale field and select Linear or Linear Constant Max from the
pop-up menu:
.
To View Thumbnail Histograms
Histicons are miniature histograms of parameter measurements that appear below the grid. These
thumbnail histograms let you see at a glance the statistical distribution of each parameter.
1. In the menu bar, touch Measure, then one of the Measure Mode buttons: Std Vertical, Std
Horizontal, or My Measure.
2. Touch the Histicons checkbox to display thumbnail histograms below the selected
parameters.
Note: For measurements set up in My Measure, you can quickly display an enlarged histogram of a thumbnail histogram by
touching the Histicon you want to enlarge. The enlarged histogram will appear superimposed on the trace it describes. This
does not apply to "Std Vertical" or "Std Horizontal" measurements.
Persistence Histogram
You can create a histogram of a persistence display also by cutting a horizontal or vertical slice
through the waveform. You also decide the width of the slice and its horizontal or vertical placement
on the waveform.
This math operation is different than the "Histogram" math operation and is not affected by Center
and Width settings made there.
To Set Up Persistence Histograms
1. In the menu bar, touch Math, then Math Setup.
2. Touch one of function tabs F1 through Fx The number of math traces available depends on
the software options loaded on your scope. See specifications..
3. Touch inside the Source1 field and select a source from the pop-up menu.
4. Touch inside the Operator1 field and select Phistogram
Operator menu.
WM-OM-E Rev I
from the Select Math
143
5. Touch the "Phistogram" tab, then touch inside the Slice Direction field and select
Horizontal or Vertical slice from the pop-up menu.
6. Touch inside the Slice Center field and enter a value, using the pop-up keypad.
7. Touch inside the Slice Width field and enter a value, using the pop-up keypad.
Note: You can use the front panel Adjust knobs to move the Slice Center line and the Slice Width boundary lines.
Persistence Trace Range
This math operation has a field where you can enter the percent of the persistence trace population
to use in creating a new waveform.
Persistence Sigma
This math operation has a field where you can enter a scale, measured in standard deviations, by
which to create a new waveform.
144
WM-OM-E Rev I
X-Stream Operator’s Manual
Histogram Parameters
fwhm
Full Width at Half Maximum
Definition: Determines the width of the largest area peak, measured between bins on either
side of the highest bin in the peak that have a population of half the highest's
population. If several peaks have an area equal to the maximum population, the
leftmost peak is used in the computation.
Description: First, the highest population peak is identified and the height of its highest bin
(population) determined (for a discussion on how peaks are determined see the
pks parameter Description:). Next, the populations of bins to the right and left are
found, until a bin on each side is found to have a population of less than 50% of
that of the highest bin's. A line is calculated on each side, from the center point of
the first bin below the 50% population to that of the adjacent bin, towards the
highest bin. The intersection points of these lines with the 50% height value is
then determined. The length of a line connecting the intersection points is the
value for fwhm.
Example:
WM-OM-E Rev I
145
fwxx
Full Width at xx% Maximum
Definition: Determines the width of the largest area peak, measured between bins on either
side of the highest bin in the peak that have a population of xx% of the highest's
population. If several peaks have an area equal to the maximum population, the
leftmost peak is used in the computation.
Description: First, the highest population peak is identified and the height of its highest bin
(population) determined (see the pks description). Next, the bin populations to
the right and left are found until a bin on each side is found to have a population
of less than xx% of that of the highest bin. A line is calculated on each side, from
the center point of the first bin below the 50% population to that of the adjacent
bin, towards the highest bin. The intersection points of these lines with the xx%
height value is then determined. The length of a line connecting the intersection
points is the value for fwxx.
Example: fwxx with threshold set to 35%:
146
WM-OM-E Rev I
X-Stream Operator’s Manual
hist ampl
Histogram Amplitude
Definition: The difference in value of the two most populated peaks in a histogram. This
parameter is useful for waveforms with two primary parameter values, such as
TTL voltages, where hampl would indicate the difference between the binary `1'
and `0' voltage values.
Description: The values at the center (line dividing the population of peak in half) of the two
highest peaks are determined (see pks parameter description:). The value of the
leftmost of the two peaks is the histogram base (see hbase). While that of the
rightmost is the histogram top (see htop). The parameter is then calculated as:
hampl = htop hbase
Example:
In this histogram, hampl is 152 mV 150 mV = 2 mV.
WM-OM-E Rev I
147
hbase
Histogram Base
Definition: The value of the leftmost of the two most populated peaks in a histogram. This
parameter is primarily useful for waveforms with two primary parameter values
such as TTL voltages where hbase would indicate the binary `0' voltage value.
Description: The two highest histogram peaks are determined. If several peaks are of equal
height the leftmost peak among these is used (see pks). Then the leftmost of the
two identified peaks is selected. This peak's center value (the line that divides the
population of the peak in half) is the hbase.
Example:
148
WM-OM-E Rev I
X-Stream Operator’s Manual
hist rms
Histogram Root Mean Square
Definition: The rms value of the values in a histogram.
Description: The center value of each populated bin is squared and multiplied by the
population (height) of the bin. All results are summed and the total is divided by
the population of all the bins. The square root of the result is returned as hrms.
Example: Using the histogram shown here, the value for hrms is:
hrms =
WM-OM-E Rev I
= 2.87
149
hist top
Histogram Top
Definition: The value of the rightmost of the two most populated peaks in a histogram. This
parameter is useful for waveforms with two primary parameter values, such as
TTL voltages, where htop would indicate the binary `1' voltage value.
Description: The two highest histogram peaks are determined. The rightmost of the two
identified peaks is then selected. The center of that peak is htop (center is the
horizontal point where the population to the left is equal to the area to the right).
Example:
150
WM-OM-E Rev I
X-Stream Operator’s Manual
maxp
Maximum Population
Definition: The count (vertical value) of the highest population bin in a histogram.
Description: Each bin between the parameter cursors is examined for its count. The highest
count is returned as maxp.
Example:
Here, maxp is 14.
WM-OM-E Rev I
151
mode
Mode
Definition: The value of the highest population bin in a histogram.
Description: Each bin between the parameter cursors is examined for its population count.
The leftmost bin with the highest count found is selected. Its center value is
returned as mode.
Example:
Here, mode is 150 mV.
152
WM-OM-E Rev I
X-Stream Operator’s Manual
pctl
Percentile
Definition: Computes the horizontal data value that separates the data in a histogram such
that the population on the left is a specified percentage `xx' of the total
population. When the threshold is set to 50%, pctl is the same as hmedian.
Description: The total population of the histogram is determined. Scanning from left to right,
the population of each bin is summed until a bin that causes the sum to equal or
exceed `xx'% of the population value is encountered. A ratio of the number of
counts needed for `xx'% population/total bin population is then determined for the
bin. The horizontal value of the bin at that ratio point of its range is found, and
returned as pctl.
Example: The total population of a histogram is 100. The histogram range is divided into 20
bins and `xx' is set to 25%. The population sum at the sixth bin from the left is 22.
The population of the seventh is 9 and its sub-range is 6.1 to 6.4 V. The ratio of
counts needed for 25% population to total bin population is:
3 counts needed / 9 counts = 1/3.
The value for pctl is:
6.1 volts + .33 * (6.4 6.1) volts = 6.2 volts.
WM-OM-E Rev I
153
pks
Peaks
Definition: The number of peaks in a histogram.
Description: The instrument analyzes histogram data to identify peaks from background noise
and histogram binning artifacts such as small gaps.
Peak identification is a 3-step process:
1. The mean height of the histogram is calculated for all populated bins. A
threshold (T1) is calculated from this mean, where:
T1= mean + 2 sqrt (mean).
2. A second threshold is determined based on all populated bins under T1 in
height, where:
T2 = mean + 2 * sigma,
and where sigma is the standard deviation of all populated bins under T1.
3. Once T2 is defined, the histogram distribution is scanned from left to right. Any
bin that crosses above T2 signifies the existence of a peak. Scanning continues
to the right until one bin or more crosses below T2. However, if the bins cross
below T2 for less than a hundredth of the histogram range, they are ignored,
and scanning continues in search of peaks that cross under T2 for more than a
hundredth of the histogram range. Scanning goes on over the remainder of the
range to identify additional peaks. Additional peaks within a fiftieth of the range
of the populated part of a bin from a previous peak are ignored.
NOTE: If the number of bins is set too high, a histogram may have many small gaps. This increases
sigma and, thereby, T2. In extreme cases, it can prevent determination of a peak, even if one appears
to be present to the eye.
Example: Here the two peaks have been identified. The peak with the highest population is
peak #1.
154
WM-OM-E Rev I
X-Stream Operator’s Manual
WM-OM-E Rev I
155
range
Range
Definition: Computes the difference between the value of the rightmost and that of the
leftmost populated bin.
Description: The rightmost and leftmost populated bins are identified. The difference in value
between the two is returned as the range.
Example:
In this example, range is 2 mV.
156
WM-OM-E Rev I
X-Stream Operator’s Manual
totp
Total Population
Definition: Calculates the total population of a histogram between the parameter cursors.
Description: The count for all populated bins between the parameter cursors is summed.
Example:
The total population of this histogram is 9.
WM-OM-E Rev I
157
xapk
X Coordinate of xxth Peak
th
Definition: Returns the value of the xx peak that is the largest by area in a histogram.
Description: First the peaks in a histogram are determined and ranked in order of total area
(for a discussion on how peaks are identified see the description for the pks
parameter). The center of the nth ranked peak (the point where the area to the left
is equal to the area to the right), where n is selected by you, is then returned as
xapk.
Example: The rightmost peak is the largest, and is thus ranked first in area (1). The leftmost
peak, although higher, is ranked second in area (2). The lowest peak is also the
smallest in area (3).
Histogram Theory of Operation
An understanding of statistical variations in parameter values is needed for many waveform
parameter measurements. Knowledge of the average, minimum, maximum, and standard
deviation of the parameter may often be enough, but in many cases you may need a more detailed
understanding of the distribution of a parameter's values.
Histograms allow you to see how a parameter's values are distributed over many measurements.
They do this by dividing a range of parameter values into sub-ranges called bins. A count of the
number of parameter values (events) that fall within ranges of the bin itself is maintained for each
bin.
158
WM-OM-E Rev I
X-Stream Operator’s Manual
While such a value range can be infinite, for practical purposes it need only be defined as large
enough to include any realistically possible parameter value. For example, in measuring TTL
high-voltage values a range of +/-50 V is unnecessarily large, whereas one of 4 V +/-2.5 V is more
reasonable. It is the 5 V range that is then subdivided into bins. And if the number of bins used were
50, each would have a range of 5 V/50 bins or 0.1 V/bin. Events falling into the first bin would then
be between 1.5 V and 1.6 V. While the next bin would capture all events between 1.6 V and 1.7 V,
and so on.
After a process of several thousand events, the bar graph of the count for each bin (its histogram)
provides a good understanding of the distribution of values. Histograms generally use the 'x' axis to
show a bin's sub-range value, and the 'Y' axis for the count of parameter values within each bin.
The leftmost bin with a non-zero count shows the lowest parameter value measurements. The
vertically highest bin shows the greatest number of events falling within its sub-range.
The number of events in a bin, peak or a histogram is referred to as its population. The following
figure shows a histogram's highest population bin as the one with a sub-range of 4.3 to 4.4 V (which
is to be expected of a TTL signal).
The lowest-value bin with events is that with a sub-range of 3.0 to 3.1 V. As TTL high voltages need
to be greater than 2.5 V, the lowest bin is within the allowable tolerance. However, because of its
proximity to this tolerance and the degree of the bin's separation from all other values, additional
investigation may be required.
Scope Process
The instrument generates histograms of the parameter values of input waveforms. But first, you
must define the following:
• The parameter to be histogrammed
WM-OM-E Rev I
159
•
The trace on which the histogram is to be displayed
•
The maximum number of parameter measurement values to be used in creating the
histogram
•
The measurement range of the histogram
•
The number of bins to be used
Some of these are pre-defined but can be changed. Once they are defined, the oscilloscope is
ready to make the histogram. The sequence for acquiring histogram data is as follows:
1. Trigger
2. Waveform acquisition
3. Parameter calculations
4. Histogram update
5. Trigger re-arm
If you set the timebase for non-segmented mode, a single acquisition occurs prior to parameter
calculations. However, in Sequence mode an acquisition for each segment occurs prior to
parameter calculations. If the source of histogram data is a memory, saving new data to memory
effectively acts as a trigger and acquisition. Because updating the screen can take much
processing time, it occurs only once a second, minimizing trigger dead time. Under remote control
the display can be turned off to maximize measurement speed.
Parameter Buffer
The oscilloscope maintains a circular parameter buffer of the last 20,000 measurements made,
including values that fall outside the set histogram range. If the maximum number of events to be
used for the histogram is a number `N' less than 20,000, the histogram will be continuously updated
with the last `N' events as new acquisitions occur. If the maximum number is greater than 20,000,
the histogram will be updated until the number of events is equal to `N.' Then, if the number of bins
or the histogram range is modified, the scope will use the parameter buffer values to redraw the
histogram with either the last `N' or 20,000 values acquired -- whichever is the lesser. The
parameter buffer thereby allows histograms to be redisplayed, using an acquired set of values and
settings that produce a distribution shape with the most useful information.
In many cases the optimal range is not readily apparent. So the scope has a powerful range finding
function. If required it will examine the values in the parameter buffer to calculate an optimal range
and redisplay the histogram using it. The instrument will also give a running count of the number of
parameter values that fall within, below, or above the range. If any values fall below or above the
range, the range finder can then recalculate to include these parameter values, as long as they are
still within the buffer.
Capture of Parameter Events
The number of events captured per waveform acquisition or display sweep depends on the
parameter type. Acquisitions are initiated by the occurrence of a trigger event. Sweeps are
equivalent to the waveform captured and displayed on an input channel (1, 2, or 3 or 4). For
non-segmented waveforms an acquisition is identical to a sweep. Whereas for segmented
160
WM-OM-E Rev I
X-Stream Operator’s Manual
waveforms an acquisition occurs for each segment and a sweep is equivalent to acquisitions for all
segments. Only the section of a waveform between the parameter cursors is used in the calculation
of parameter values and corresponding histogram events.
The following table provides a summary of the number of histogram events captured per acquisition
or sweep for each parameter, and for a waveform section between the parameter cursors.
Parameters
duty, freq, period, width, time@lev, f@level,
f80-20%, fall, r@level, r20-80%, rise
Number of Events Captured
All events in the acquisition
ampl, area, base, cmean, cmedian, crms, csdev, One event per acquisition
cycles, delay, maximum, mean, minimum, nbph,
nbpw, over+, over-, pkpk, npts, rms, sdev, dly
Histogram Parameters (XMAP and JTA2 Options)
Once a histogram is defined and generated, measurements can be performed on the histogram
itself. Typical of these are the histogram's
•
average value, standard deviation
•
most common value (parameter value of highest count bin)
•
leftmost bin position (representing the lowest measured waveform parameter value)
•
rightmost bin (representing the highest measured waveform parameter value)
Histogram parameters are provided to enable these measurements. Available through selecting
"Statistics" from the "Category" menu, they are calculated for the selected section between the
parameter cursors:
fwhm full width (of largest peak) at half the maximum bin
fwxx full width (of largest peak) at xx% the maximum bin
hist ampl histogram amplitude between two largest peaks
hist base histogram base or leftmost of two largest peaks
hist max value of the highest (right-most) populated bin in a histogram
hist mean average or mean value of data in the histogram
hist median value of the x-axis of a histogram that divides the population into two equal halves
hist min value of the lowest (left-most) populated bin in a histogram
hist rms rms value of data in histogram
hist sdev standard deviation of values in a histogram
hist top histogram top or rightmost of two largest peaks
max populate population of most populated bin in histogram
mode data value of most populated bin in histogram
WM-OM-E Rev I
161
percentile data value in histogram for which specified `x'% of population is smaller
peaks number of peaks in histogram
pop @ x population of bin for specified horizontal coordinate
range difference between highest and lowest data values
total pop total population in histogram
x at peak x-axis position of specified largest peak
Histogram Peaks
Because the shape of histogram distributions is particularly interesting, additional parameter
measurements are available for analyzing these distributions. They are generally centered around
one of several peak value bins, known, with its associated bins, as a histogram peak.
Example: In the following figure, a histogram of the voltage value of a five-volt amplitude square
wave is centered around two peak value bins: 0 V and 5 V. The adjacent bins signify variation due
to noise. The graph of the centered bins shows both as peaks.
162
WM-OM-E Rev I
X-Stream Operator’s Manual
Determining such peaks is very useful because they indicate dominant values of a signal. However,
signal noise and the use of a high number of bins relative to the number of parameter values
acquired, can give a jagged and spiky histogram, making meaningful peaks hard to distinguish. The
scope analyzes histogram data to identify peaks from background noise and histogram definition
artifacts such as small gaps, which are due to very narrow bins.
Binning and Measurement Accuracy
Histogram bins represent a sub-range of waveform parameter values, or events. The events
represented by a bin may have a value anywhere within its sub-range. However, parameter
measurements of the histogram itself, such as average, assume that all events in a bin have a
single value. The scope uses the center value of each bin's sub-range in all its calculations. The
greater the number of bins used to subdivide a histogram's range, the less the potential deviation
between actual event values and those values assumed in histogram parameter calculations.
Nevertheless, using more bins may require that you perform a greater number of waveform
parameter measurements, in order to populate the bins sufficiently for the identification of a
characteristic histogram distribution.
In addition, very fine grained binning will result in gaps between populated bins that may make it
difficult to determine peaks.
The oscilloscope's 20,000-parameter buffer is very effective for determining the optimal number of
bins to be used. An optimal bin number is one where the change in parameter values is insignificant,
and the histogram distribution does not have a jagged appearance. With this buffer, a histogram
can be dynamically redisplayed as the number of bins is modified by the user. In addition,
depending on the number of bins selected, the change in waveform parameter values can be seen.
WM-OM-E Rev I
163
WAVEFORM MEASUREMENTS
Measuring with Cursors
Cursors are important tools that aid you in measuring signal values. Cursors are markers --- lines,
cross-hairs, or arrows --- that you can move around the grid or the waveform itself. Use cursors to
make fast, accurate measurements and to eliminate guesswork. There are two basic types:
y
Horiz(ontal) (generally Time or Frequency) cursors are markers that you move
horizontally along the waveform. Place them at a desired location along the time axis to
read the signal’s amplitude at the selected time.
y
Vert(ical) (Voltage) cursors are lines that you move vertically on the grid to measure the
amplitude of a signal.
Cursors Setup
Cursor Measurement Icons
The Readout icons depict what is being measured for each measurement mode.
Each cursor locates a point on the waveform. The cursor values can
be read in the descriptor label for the trace. Use the Position data
entry fields at the right side of the dialog to place the cursors precisely.
This is the difference in Y values. The value can be read in the
descriptor label for the trace.
Displays absolute and delta cursors together.
This gives the slope between cursors.
If there are non-time-domain waveforms displayed, there will also be a menu offering choices of
x-axis units: s or Hz, for example.
Cursors Setup
Quick Display
At any time, you can change the display of cursor types (or turn them off) without invoking the
"Cursors Setup" dialog as follows:
1. In the menu bar, touch Cursors, then Off, Abs Horizontal, Rel Horizontal, Abs Vertical,
or Rel Vertical.
2. The cursors displayed will assume the positions previously set up. If you want to change
their position or measurement mode, in the menu bar touch Cursors, then Cursors Setup
in the drop-down menu.
164
WM-OM-E Rev I
X-Stream Operator’s Manual
Full Setup
1. In the menu bar, touch Cursors, then Cursors Setup. The "Standard Cursors" dialog
opens.
2. In the dialog area, touch the Cursors On check box to display them.
3. Touch one of the Horizontal or Vertical mode buttons: Relative or Absolute.
4. If you chose a Relative mode, also touch a readout parameter button: Y position, delta Y, or
slope.
5. If you chose a Relative mode, touch inside the Position 1 and Position 2 data entry fields
and type in a value for each cursor. You can also use the Cursors knobs on the front panel
to place the cursors. If you chose an Absolute mode, do the same for your single cursor.
6. If you chose a Relative mode and you would like both cursors to move in unison as you
adjust the position, touch the Track check box to enable tracking.
Overview of Parameters
Parameters are measurement tools that determine a wide range of waveform properties. Use them
to automatically calculate many attributes of your waveform, like rise-time, rms voltage, and
peak-to-peak voltage, for example.
There are parameter modes for the amplitude and time domains, custom parameter groups, and
parameters for pass and fail testing. You can make common measurements on one or more
waveforms.
To Turn On Parameters
1. Touch Measure in the menu bar, then Measure Setup... in the drop-down menu.
2. Touch inside the On checkbox for each parameter you want to display.
Quick Access to Parameter Setup Dialogs
You can quickly gain access to a parameter setup dialog by touching the parameter list box below
the grid. For example, touching within P1 below the grid
displays the setup dialog for P1:
WM-OM-E Rev I
165
Touching the row titles
displays the top Measure dialog.
Status Symbols
Below each parameter appears a symbol that indicates the status of the parameter, as follows:
A green check mark means that the scope is returning a valid value.
A crossed-out pulse means that the scope is unable to determine
top and base; however, the measurement could still be valid.
A downward pointing arrow indicates an underflow condition.
An upward pointing arrow indicates an overflow condition.
An upward-and-downward pointing arrow indicates an underflow
and overflow condition.
166
WM-OM-E Rev I
X-Stream Operator’s Manual
Using X-Stream Browser to Obtain Status Information
Example:
Here is a case of an overflow condition, in which the amplitude of the waveform cannot be
determined:
1. Minimize the scope display by selecting File Minimize.
2. Touch the X-Stream Browser desktop icon to open the browser:
3. Touch the left scope icon ("Connect to a local X-Stream DSO device") in the X-Stream
Browser toolbar:
4. Select Measure Parameter in error (P1) Out Result:
WM-OM-E Rev I
167
5. Read the status information in line StatusDescription.
168
WM-OM-E Rev I
X-Stream Operator’s Manual
Statistics
By touching the Statistics On checkbox in the "Measure" dialog, you can display statistics for
standard vertical or horizontal parameters, or for custom parameters. The statistics that are
displayed are as follows:
value (last)
mean
min.
max.
sdev
num
The values displayed in the num row is the number of measurements computed. For any
parameter that computes on an entire waveform (like edge@level, mean, minimum, maximum,
etc.) the value displayed represents the number of sweeps.
For any parameter that computes on every event, the value displayed is equal to the number of
events per acquired waveform. If x waveforms were acquired, the value represents x times the
number of cycles per waveform. Also, the "value" is equal to the measurement of the last cycle on
the last acquisition.
To Apply a Measure Mode
1. In the menu bar, touch Measure, then Measure Setup.
2. Choose a Measure Mode from the dialog. The parameters are displayed below the grid.
Measure Modes
The selections for Measure Mode allow you to quickly apply parameters for standard vertical and
standard horizontal setups, and custom setups.
Standard Vertical Parameters
These are the default Standard Vertical Parameters:
Vertical
mean
sdev
max.
min.
ampl
WM-OM-E Rev I
169
pkpk
top
base
Standard Horizontal Parameters
These are the default Standard Horizontal Parameters:
Horizontal
freq
period
width
rise
fall
delay
duty
npoints
My Measure
You can choose to customize up to eight parameters by touching My Measure.
Parameter Math (XMath or XMAP option required)
The instrument gives you the ability to perform arithmetic operations (addition, subtraction,
multiplication, division) on the results of two parameter measurements. Alternatively, you can apply
math to a single parameter (for example, invert). By customizing parameters in this way, you can
effectively extend the range of parameter measurements based on your particular needs.
Logarithmic Parameters
The parameter math feature prevents multiplication and division of parameters that return
logarithmic values. These parameters are as follows:
170
•
auto-correlation signal-to-noise ratio (ACSN)
•
narrow-band power (NBPW)
•
media signal-to-noise ratio (MSNR)
•
residual signal-to-noise ratio (RSNR)
•
top-to-base ratio when the units are in dB (TBR)
WM-OM-E Rev I
X-Stream Operator’s Manual
Excluded Parameters
Parameters that are already the result of parameter math operations are excluded. If they are
included in a remote control setup command, an error message is generated and the setup
canceled.
•
Excluded parameters are as follows:
•
delta clock-to-data near (DC2D)
•
delta clock-to-data next (DC2DPOS)
•
delta clock-to-data previous (DC2DNEG)
•
delta delay (DDLY)
•
delta time at level (DTLEV)
•
phase (PHASE)
•
resolution (RES)
•
mTnTmT shift (BEES)
•
mTnTmT shift sigma (BEESS)
•
mTnTmT shift sigma - list (BEESS)
Parameter Script Parameter Math
In addition to the arithmetic operations, the Parameter Math feature allows you to use VBScript or
JavaScript to write your own script for one or two measurements and produce a result that suits
your needs. Code entry is done in the Script Editor window directly on the instrument. You can also
import an existing script.
WM-OM-E Rev I
171
Param Script vs. P Script
Param Script is a VBScript or JavaScript that operates on one or two waveforms and outputs a
parameter measurement, as shown in the figure below. P Script, on the other hand, is another
VBScript or JavaScript that takes as input one or two parameters and performs a math operation on
them to produce another parameter output.
The inputs to Param Script can also be math (F1-Fx) or memory (M1-Mx) traces. The inputs to P
Script can be the results of any parameter measurement, not necessarily Param Script.
172
WM-OM-E Rev I
X-Stream Operator’s Manual
To Set Up Parameter Math
1. Touch Measure in the menu bar, then Measure Setup... in the drop-down menu.
2. Touch the My Measure button in the "Measure" dialog.
3. Touch the Px tab for the parameter to which you want to apply parameter math.
4. In the "Px" dialog, touch the math on parameters button
expand to two fields.
. The Source field will
5. Touch inside the Source1 and Source2 fields and select the parameters you want to apply
math to (P1 to Px). If you are applying math to a single parameter (for example, invert), just
touch inside the Source1 field and select a parameter (P1 to Px).
6. Touch inside the Math Operator field and select a math operation from the Select
Measurement menu. If you select an operation that requires two input parameters, the
Source field will expand to two fields.
To Set Up Parameter Script Math
1. Touch Measure in the menu bar, then Measure Setup... in the drop-down menu.
2. Touch the My Measure button in the "Measure" dialog.
3. Touch the Px tab for the parameter to which you want to apply parameter math.
4. In the "Px" dialog, touch the math on parameters button
expand to two fields.
. The Source field will
5. Touch inside the Source1 and Source2 fields and select the parameters you want to apply
WM-OM-E Rev I
173
math to (P1 to Px). If you are applying math to a single parameter (for example, invert), just
touch inside the Source1 field and select a parameter (P1 to Px).
6. Touch inside the Math Operator field and select
Measurement menu.
P Script from the Select
7. In the "Script Math" dialog, touch inside the Script Language field and select either
VBScript or JScript from the pop-up menu.
8. Touch the Edit Code button; the Script Editor window opens. You can enter code in this
window or call up an existing script from a file storage location. If you create your script in
this window, you can then export it and save it to file.
Measure Gate
Using Measure Gate, you can narrow the span of the waveform on which to perform parameter
measurements, allowing you to focus on the area of greatest interest. You have the option of
dragging the gate posts horizontally along the waveform, or specifying a position down to
hundredths of a division. The default starting positions of the gate posts are 0 div and 10 div, which
coincide with the left and right ends of the grid. The gate, therefore, initially encloses the entire
waveform.
Note: If you have Grid On Top enabled, you will not see the gate posts in their default position at each end of the grid. But if
you touch either end of the grid, a drag cursor
drag it.
174
will appear, indicating that you have control of the post and can now
WM-OM-E Rev I
X-Stream Operator’s Manual
In this example, you can see that the Measure Gate includes only five rising edges. Therefore,
parameter calculations for rise time are performed only on the five pulses bounded by the gate
posts. The position of the gate posts is shown in the Start and Stop fields in the accompanying
dialog.
To Set Up Measure Gate
1. In the menu bar, touch Measure Setup...
2. Touch the Px tab for the parameter you want to gate. A mini-dialog to the right of the main
setup dialog opens.
Note: If you already have the parameter of interest set up, you can simply touch the parameter directly below the grid:
Example Parameter Readout
3. Touch inside the Start data entry field and enter a value, using the pop-up numeric keypad.
Or, you can simply touch the leftmost grid line and drag the gate post to the right.
4. Touch inside the Stop data entry field and enter a value, using the pop-up numeric keypad.
Or, you can simply touch the rightmost grid line and drag the gate post to the left.
WM-OM-E Rev I
175
Help Markers
Help Markers clarify parameter measurements by displaying movable cursors and a visual
representation of what is being measured. For the "at level" parameters, Help Markers make it
easier to see where your waveform intersects the chosen level. This feature also displays the
hysteresis band that you have set about that level.
You also have the option, by means of an Always On checkbox, to leave the Help Markers
displayed after you have closed the Help Markers setup dialog.
You have a choice of Simple or Detailed views of the markers:
•
The Simple selection produces cursors and Measure Gate gate posts. The gate posts
are independently placeable for each parameter.
•
The Detailed selection produces cursors, Measure Gate gate posts, a label identifying
the parameter being measured, and a level indicator and hysteresis band for "at level"
parameters (not part of Standard Horizontal or Standard Vertical parameters).
Standard Horizontal Parameter Help Markers
176
WM-OM-E Rev I
X-Stream Operator’s Manual
Standard Vertical Parameter Help Markers
To Set Up Help Markers
1. In the menu bar, touch Measure Setup...
2. Select a Measure Mode: Std Vertical, Std Horizontal, or My Measure.
3. Touch the Show All button
to display Help Markers for every parameter
being measured on the displayed waveform (C2 in the examples above).
4. Touch inside the Help Markers field and select Simple The Simple selection produces
cursors and Measure Gate gate posts. The gate posts are independently placeable for
each parameter. or Detailed The Detailed selection produces cursors, Measure Gate gate
posts, a label identifying the parameter being measured, and a level indicator and
hysteresis band for "at level" parameters..
Note: The choice of Simple or Detailed is applied to all parameters at the same time. That is, if you choose Simple markers
for one parameter, all parameters will be displayed in this mode.
5. Touch the Always On checkbox if you want to continuously display Help Markers for this
parameter.
WM-OM-E Rev I
177
To Turn Off Help Markers
1. Touch the Clear All button
to turn off Help Markers for all parameters.
2. To turn off Help Markers for individual parameters, touch the Px tab for the parameter in
question. Then uncheck the Always On checkbox. When you close this dialog, the Help
Markers for this parameter will no longer be displayed.
178
WM-OM-E Rev I
X-Stream Operator’s Manual
To Customize a Parameter
From the Measure Dialog
1.
Touch the My Measure button in the "Measure" dialog. The dialog presents you with a
panel of eight preset parameters.
2.
For each parameter, touch the On check box to enable the parameter listed.
3.
If you want to change the parameter listed, or a measurement characteristic, touch the
parameter button (P1 for example) alongside the check box. A pop-up menu of parameters
categorized by type appears. To display parameter icons only, touch the icon button
at the bottom of the menu. To display the icons in list form, along with an
explanation of each parameter, touch the list button
scroll through the list of icons.
. Use the Up/Down buttons to
4.
When you make a selection from the parameter icon menu, the setup dialogs for that
parameter appear. You can then change the waveform source and other conditions of the
parameter.
5.
If you are setting up an "@level" parameter, make selections for Level type (percent or
absolute), Slope (positive, negative, both), and Hysteresis level.
6.
Touch the Gate tab, and set the position of the gate posts.
From a Vertical Setup Dialog
1.
In the "Cx Vertical Adjust" dialog, touch the Measure button
.
2.
Select a parameter from the pop-up menu. (The Actions for trace source defaults to the
channel or trace whose dialog is open. If a parameter, it goes into the next "available"
parameter, or the last one if all are used.)
3.
Select another parameter or touch Close.
From a Math Setup Dialog
1.
In the "Fx" dialog, touch the Measure button
2.
Select a parameter from the pop-up menu. (The Actions for trace source defaults to the
channel or trace whose dialog is open. If a parameter, it goes into the next "available"
parameter, or the last one if all are used.)
3.
Select another parameter or touch Close.
WM-OM-E Rev I
.
179
Parameter Calculations
Parameters and How They Work
Determining Top and Base Lines
Proper determination of the top and base reference lines is fundamental for ensuring correct
parameter calculations. The analysis begins by computing a histogram of the waveform data over
the time interval spanned by the left and right time cursors. For example, the histogram of a
waveform transitioning in two states will contain two peaks (see Figure 1). The analysis will attempt
to identify the two clusters that contain the largest data density. Then the most probable state
(centroids) associated with these two clusters will be computed to determine the top and base
reference levels: the top line corresponds to the top and the base line to the bottom centroid.
Figure 1
Determining Rise and Fall Times
Once top and base are estimated, calculation of the rise and fall times is easily done (see Figure 1).
The 90% and 10% threshold levels are automatically determined by the DDA-5005A, using the
amplitude (ampl) parameter.
Threshold levels for rise or fall time can also be selected using absolute or relative settings (r@level,
f@level). If absolute settings are chosen, the rise or fall time is measured as the time interval
separating the two crossing points on a rising or falling edge. But when relative settings are chosen,
the vertical interval spanned between the base and top lines is subdivided into a percentile scale
(base = 0 %, top = 100 %) to determine the vertical position of the crossing points.
180
WM-OM-E Rev I
X-Stream Operator’s Manual
The time interval separating the points on the rising or falling edges is then estimated to yield the
rise or fall time. These results are averaged over the number of transition edges that occur within
the observation window.
Rising Edge Duration
Falling Edge Duration
Where Mr is the number of leading edges found, Mf the number of
trailing edges found,
x% level,
level.
the time when rising edge i crosses the
and the time when falling edge i crosses the x%
Determining Time Parameters
Time parameter measurements such as width, period and delay are carried out with respect to the
mesial reference level (see Figure 2), located halfway (50%) between the top and base reference
lines.
Time-parameter estimation depends on the number of cycles included within the observation
window. If the number of cycles is not an integer, parameter measurements such as rms or mean
will be biased. However, only the last value is actually displayed, the mean being available when
statistics are enabled. To avoid these bias effects, the instrument uses cyclic parameters, including
crms and cmean, that restrict the calculation to an integer number of cycles.
WM-OM-E Rev I
181
Figure 2
Determining Differential Time Measurements
The DDA-5005A enables accurate differential time measurements between two traces: for
example, propagation, setup and hold delays (see Figure 3).
Parameters such as Delta c2d+/- require the transition polarity of the clock and data signals to be
specified.
182
WM-OM-E Rev I
X-Stream Operator’s Manual
Figure 3
Moreover, a hysteresis range may be specified to ignore any spurious transition that does not
exceed the boundaries of the hysteresis interval. In Figure 3, Delta c2d- (1, 2) measures the time
interval separating the rising edge of the clock (trigger) from the first negative transition of the data
signal. Similarly, Delta c2d+ (1, 2) measures the time interval between the trigger and the next
transition of the data signal.
Level and Slope
For several time based measurements, you can choose positive, negative, or both slopes to begin
parameter measurements. For two-input parameters, such as Dtime@level, you can specify the
slope for each input, as well as the level and type (percent or absolute).
WM-OM-E Rev I
183
List of Parameters
The following table describes the instrument parameters. Availability of some parameters
depends on the options installed. See the comments in the "Notes" column of the table.
Parameter
Description
Definition
Notes
100BT Fall
Fall time between 2 levels
(upper-base, base-lower) of a
3-level signal (100BT)
Available with ENET
option.
100BT Rise
Rise time between 2 levels
(Lower-base, base-upper) of a
3-level signal (100BT)
Available with ENET
option.
100BT TIE
Difference between the measured
and ideal times at level between
base and upper orlower levels of
100BT signal.
Available with ENET
option.
100BT Tj
Total jitter from a TIE at level
between base and upper or lower
levels of 100BTsignal.
Available with ENET
option.
ACSN
Auto-correlation Signal-to-Noise
provides a signal-to-noise ratio for
periodic waveforms.
Available with DDM2
option.
AltNCycle
Alternate N-Cycle Plot. Timing of
the transitions in the data waveform
is measured for each transition and
plotted as a function of the number
of unit intervals over which the
timing is measured. The N-cycle
plot displays the mean or standard
deviation of the edge placement in
the waveform relative to each other
(data to data) or to a reference clock
(clock to data).
Available with ASDA
option.
Amplitude
Measures the difference between top - base
upper and lower levels in two-level
signals. Differs from pkpk in that
noise, overshoot, undershoot, and
ringing do not affect the
measurement.
On signals not having
two major levels (such
as triangle or saw-tooth
waves), returns same
value as pkpk.
Ampl asym
Amplitude asymmetry between
taa+ and taa-
Standard in
DDA-5005A.
Standard parameter.
1 |(taa+ - taa-)|/(taa+ - taa-) Hysteresis argument
used to discriminate
levels from noise in
data.
Available with DDM2
184
WM-OM-E Rev I
X-Stream Operator’s Manual
option.
Standard in
DDA-5005A.
Area
Integral of data: Computes area of Sum from first to last of data Standard parameter..
waveform between cursors relative multiplied by horizontal time
to zero level. Values greater than between points
zero contribute positively to the
area; values less than zero
negatively.
Avg Power
Average power of the waveform
Available with SDA and
SDM options.
Standard in SDA100G
scopes.
Base
Lower of two most probable states Value of most probable lower On signals not having
(higher is top). Measures lower
state
two major levels
level in two-level signals. Differs
(triangle or saw-tooth
from min in that noise, overshoot,
waves, for example),
undershoot, and ringing do not
returns same value as
affect measurement.
min.
Standard parameter.
Bit Rate
One over duration of one UI
measured on an eye
Available with SDA
option.
Standard in SDA,
SDA100G, and
WaveExpert scopes.
CMACp
PCI Express V TX-CM-ACp and V
RX-CM-Acp
Cycles
Determines number of cycles of a
periodic waveform lying between
cursors. First cycle begins at first
transition after the left cursor.
Transition may be positive- or
negative-going.
cyclic
Cyclic mean: Computes the
Average of data values of an Choose this parameter
average of waveform data. Contrary integral number of periods by selecting Mean from
to mean, computes average over an
the parameter table,
then touching the Cyclic
integral number of cycles,
eliminating bias caused by
checkbox.
fractional intervals.
Standard parameter.
Mean
WM-OM-E Rev I
Available with PCIE
option.
Number of cycles of periodic Standard parameter.
waveform
185
cyclic
Median
Cyclic median: Computes average Data value for which 50% of
of base and top values over an
values are above and 50%
integral number of cycles, contrary below
to median, eliminating bias caused
by fractional intervals.
Choose this parameter
by selecting Median
from the parameter
table, then touching the
Cyclic checkbox.
Standard parameter.
cyclic
RMS
Cyclic root mean square: Computes
square root of sum of squares of
data values divided by number of
points. Contrary to rms, calculation
is performed over an integral
number of cycles, eliminating bias
caused by fractional intervals.
Where: vi denotes
measured sample
values, and N = number
of data points within the
periods found.
Choose this parameter
by selecting RMS from
the parameter table,
then touching the Cyclic
checkbox.
Standard parameter.
cyclic
Std dev
Cyclic standard deviation: Standard
deviation of data values from mean
value over integral number of
periods. Contrary to sdev,
calculation is performed over an
integral number of cycles,
eliminating bias caused by
fractional intervals.
Where: vi denotes
measured sample
values, and N = number
of data points within the
periods found.
Choose this parameter
by selecting Std dev
from the parameter
table, then touching the
Cyclic checkbox.
Standard parameter.
DCD
Amount of jitter due to duty cycle
distortion
Available with SDA and
ENET options.
Standard in SDA and
WaveExpert scopes.
DDj
Amount of data dependent jitter in a
signal
Available with SDA
option.
Delay
Time from trigger to transition:
Time between trigger and
Measures time between trigger and first 50% crossing after left
first 50% crossing after left cursor. cursor
Can measure propagation delay
between two signals by triggering
on one and determining delay of
other.
Standard parameter.
186
WM-OM-E Rev I
X-Stream Operator’s Manual
Delta delay
delay: Computes time between
50% level of two sources.
Time between midpoint
transition of two sources
Standard parameter.
Dj Effective
Amount of deterministic jitter
(estimated) in a signal
Available with SDA
option.
DOV
Differential Output Voltage of a
100Base-T signal
Available with ENET
option.
Dperiod@level
Adjacent cycle deviation
(cycle-to-cycle jitter) of each cycle
in a waveform
Reference levels and
edge-transition polarity
can be selected.
Hysteresis argument
used to discriminate
levels from noise in
data.
Available with JTA2 and
XMAP options.
Standard in SDA100G
scopes.
Droop FG
1000Base-T test mode 1 droop
from F to G
Available with ENET
option.
Droop HJ
1000Base-T test mode 1 droop
from H to J
Available with ENET
option.
Dtime@level
Reference levels and
t at level: Computes transition
Time between transition
between selected levels or sources. levels of two sources, or from edge-transition polarity
trigger to transition level of a can be selected.
Hysteresis argument
single source
used to discriminate
This measurement gives the levels from noise in
time of the source 2 edge
data.
minus the time of the source
1 edge.
Standard parameter.
Dtrig Time
Time from last trigger to this trigger
Duration
For single sweep waveforms, dur is
0; for sequence waveforms: time
from first to last segment's trigger;
for single segments of sequence
waveforms: time from previous
segment's to current segment's
trigger; for waveforms produced by
a history function: time from first to
last accumulated waveform's
trigger.
WM-OM-E Rev I
Standard in
WaveRunner 6000A,
WavePro 7000A,
WaveMaster, and
sampling scopes.
Time from first to last
acquisition: for average,
histogram or sequence
waveforms
Standard parameter.
187
Duty@level
Percent of period for which data are
above or below a specified level.
Reference levels and
edge-transition polarity
can be selected.
Hysteresis argument
used to discriminate
levels from noise in
data.
Available with JTA2 and
XMAP options.
Duty cycle
Duty cycle: Width as percentage of width/period
period.
Standard parameter.
Dwidth@level
Difference of adjacent width above
or below a specified level.
Reference levels and
edge-transition polarity
can be selected.
Hysteresis argument
used to discriminate
levels from noise in
data.
Available with JTA2 and
XMAP options.
Standard in SDA100G
scopes.
Edge@level
Number of edges in waveform.
Reference levels and
edge-transition polarity
can be selected.
Hysteresis argument
used to discriminate
levels from noise in
data.
Available with JTA2,
USB2, SDA, and XMAP
options.
Standard in SDA100G
and WavePro 7000A
scopes.
Ext Ratio
Ratio of the power levels of an eye
diagram
Available with SDA and
SDM options.
Standard in SDA,
SDA100G, and
WaveExpert scopes.
188
WM-OM-E Rev I
X-Stream Operator’s Manual
Excel
Performs measurements in Excel
by transferring one or two
waveforms and reading the
resulting parameter value.
Available with XMAP
and XDEV options.
Standard on
DDA-5005A scope.
Excel must be loaded on
the instrument.
Eye AC RMS
Root mean square of data within
one UI
Standard in SDA and
WaveExpert scopes.
Eye Amplitude
Difference of the levels of an eye
diagram
Available with SDA and
SDM options.
Standard in SDA,
SDA100G, and
WaveExpert scopes.
Eye BER
Bit Error Rate estimated from an
eye diagram
Available with SDA and
SDM options.
Standard in SDA,
SDA100G, and
WaveExpert scopes.
Eye Bit Rate
One over duration of one UI
measured on an eye
Standard in SDA and
WaveExpert scopes.
Eye Bit Time
Duration of one UI measured on an
eye
Standard in SDA and
WaveExpert scopes.
Eye Crossing
Level of the crossing in an eye
diagram
Available with SDA and
SDM options.
Standard in SDA,
SDA100G, and
WaveExpert scopes.
Eye CrossN
Time of first crossing 50% level with
negative edge of an eye relative to
trigger or eye reference
Standard in SDA and
WaveExpert scopes.
Eye CrossP
Time of first crossing 50% level with
positive edge of an eye relative to
trigger or eye reference
Standard in SDA and
WaveExpert scopes.
Eye Cyc Area
The area under the mean
persistence trace under first UI
Standard in SDA and
WaveExpert scopes.
Eye Delay
Time of first crossing of an eye
relative to trigger or eye reference
Standard in SDA and
WaveExpert scopes.
Eye Delt Dly
Delay of crossing times between
two eyes
Standard in SDA and
WaveExpert scopes.
Eye FallTime
Fall time of the mean of persistence
data
Standard in SDA and
WaveExpert scopes.
WM-OM-E Rev I
189
Eye Height
Size of the vertical opening of an
eye diagram
Available with SDA and
SDM options.
Standard in SDA,
SDA100G, and
WaveExpert scopes.
Eye Mean
Mean level of an eye
Standard in SDA and
WaveExpert scopes.
Eye Open Fac
Eye opening factor measured within
the eye aperture
Standard in SDA and
WaveExpert scopes.
Eye OverN
Negative overshoot measured on
an eye
Standard in SDA and
WaveExpert scopes.
Eye OverP
Positive overshoot measured on an
eye
Standard in SDA and
WaveExpert scopes.
Eye Pk Noise
Peak-to-peak noise of a level of an
eye diagram
Standard in SDA and
WaveExpert scopes.
Eye PkPk Jit
Peak-to-peak jitter measured on
eye persistence
Standard in SDA and
WaveExpert scopes.
Eye Pulse Wid
The width of the eye measured at
mid level
Standard in SDA and
WaveExpert scopes.
Eye Q Factor
Q factor measured within the eye
aperture
Available with SDA and
SDM options.
Standard in SDA,
SDA100G, and
WaveExpert scopes.
Eye RiseTime
Rise time of the mean of
persistence data
Standard in SDA and
WaveExpert scopes.
Eye RMS Jit
Root mean square jitter of an eye
Standard in SDA and
WaveExpert scopes.
Eye SD Noise
The standard deviation of data on
one eye level
Standard in SDA and
WaveExpert scopes.
Eye SgToNoise
Signal to noise of an eye diagram
Standard in SDA and
WaveExpert scopes.
Eye SupRatio
Suppression ratio of an eye
Standard in SDA and
WaveExpert scopes.
Eye Width
Size of the horizontal opening of an
eye diagram
Available with SDA and
SDM options.
Standard in SDA,
SDA100G, and
WaveExpert scopes.
190
WM-OM-E Rev I
X-Stream Operator’s Manual
Fall time
Fall time: Duration of falling edge
from 90-10%.
Time at upper threshold
minus
Time at lower threshold
averaged over each falling
edge
Threshold arguments specify two
vertical values on each edge used
to compute fall time. Formulas for
upper and lower values:
On signals not having
two major levels
(triangle or saw-tooth
waves, for example), top
and base can default to
maximum and
minimum, giving,
however, less
predictable results.
Standard parameter.
lower = lower thresh. x amp/100 +
base
upper = upper thresh. x amp/100 +
base
Fall 80-20%
Fall 80-20%: Duration of pulse
Average duration of falling
waveform's falling transition from
80-20% transition
80% to 20%, averaged for all falling
transitions between the cursors.
On signals not having
two major levels
(triangle or saw-tooth
waves, for example), top
and base can default to
maximum and
minimum, giving,
however, less
predictable results.
Standard parameter.
Fall@level
Transition time for % or absolute On signals not having
Fall at level: Duration of pulse
waveform's falling edges between levels of all falling edges.
two major levels
user-specified transition levels. See Enhanced version sets
(triangle or saw-tooth
measurement calculations to
also Rise@level.
waves, for example), top
use one of the following:
and base can default to
maximum and
Base & Top (% or absolute)
minimum, giving,
Peak-Peak (%)
however, less
0V-Min (%)
predictable results.
Standard parameter.
Enhanced parameter
available with EMC
option.
First
WM-OM-E Rev I
Indicates value of horizontal axis at Horizontal axis value at left
left cursor.
cursor
Indicates location of left
cursor. Cursors are
interchangeable: for
example, the left cursor
may be moved to the
right of the right cursor
and first will give the
location of the cursor
191
formerly on the right,
now on left.
Standard parameter.
Frequency
Frequency: Period of cyclic signal 1/period
measured as time between every
other pair of 50% crossings.
Starting with first transition after left
cursor, the period is measured for
each transition pair. Values then
averaged and reciprocal used to
give frequency.
Standard parameter.
Freq@level
Frequency at a specific level and
slope for every cycle in waveform.
Reference levels and
edge-transition polarity
can be selected.
Hysteresis argument
used to discriminate
levels from noise in
data.
Available with JTA2 and
XMAP options.
Standard in SDA100G
and WavePro 7000A
scopes.
FWHM
Measures the width of the largest
area histogram peak at half of the
population of the highest peak.
Available with DDM2,
JTA2, XMATH, XWAV,
CAN02, SDA, and
XMAP options.
Standard in
DDA-5005A, SDA100G,
and WaveExpert
scopes.
FWxx
Measures the width of the largest
area histogram peak at xx% of the
population of the highest peak.
Available with DDM2,
JTA2, XMATH, XWAV,
CAN02, SDA, and
XMAP options.
Standard in
DDA-5005A, SDA100G,
WaveExpert, and
sampling scopes.
Half period
Half period of a waveform.
Reference levels and
edge-transition polarity
can be selected.
Hysteresis argument
used to discriminate
levels from noise in
192
WM-OM-E Rev I
X-Stream Operator’s Manual
data.
Available with JTA2,
SDA, and XMAP
options.
Standard in SDA100G
scopes.
Hist ampl
Difference in value between the two
most populated peaks in a
histogram.
Available with DDM2,
JTA2, XMATH, XWAV,
CAN02, SDA, and
XMAP options.
Standard in
DDA-5005A, SDA100G,
WaveExpert, and
sampling scopes.
Hist base
Value of the left-most of the two
most populated histogram peaks.
Available with DDM2,
JTA2, XMATH, XWAV,
CAN02, SDA, and
XMAP options.
Standard in
DDA-5005A, SDA100G,
WaveExpert, and
sampling scopes.
Hist maximum
Value of the highest (right-most)
populated bin in a histogram.
Available with DDM2,
JTA2, XMATH, XWAV,
CAN02, SDA, and
XMAP options.
Standard in
DDA-5005A, SDA100G,
WaveExpert, and
sampling scopes.
Hist Max Pop
Peak with maximum population in a
histogram.
Available with DDM2,
JTA2, XMATH, XWAV,
CAN02, SDA, and
XMAP options.
Standard in
DDA-5005A, SDA100G,
WaveExpert, and
sampling scopes.
Hist mean
Average or mean value of data in
the histogram.
Available with DDM2,
JTA2, XMATH, XWAV,
CAN02, SDA, and
XMAP options.
Standard in
DDA-5005A, SDA100G,
and WaveExpert
WM-OM-E Rev I
193
scopes.
Hist median
Value of the "X" axis of a histogram
that divides the population into two
equal halves.
Available with DDM2,
JTA2, XMATH, XWAV,
CAN02, SDA, and
XMAP options.
Standard in
DDA-5005A, SDA100G,
WaveExpert, and
sampling scopes.
Hist minimum
Value of the lowest (left-most)
populated bin in a histogram.
Available with DDM2,
JTA2, XMATH, XWAV,
CAN02, SDA, and
XMAP options.
Standard in
DDA-5005A, SDA100G,
and WaveExpert
scopes.
Hist Mode
Position of the highest histogram
peak.
Available with DDM2,
JTA2, XMATH, XWAV,
CAN02, SDA, and
XMAP options.
Standard in
DDA-5005A, SDA100G,
WaveExpert, and
sampling scopes.
Hist Pop@X
Hist Range
Population at bin for specified
horizontal coordinate. You can
place the cursor at any bin and use
either Absolute, Reference, or
Difference cursor shape.
Available with DDM2,
JTA2, SDM, XMATH,
XWAV, CAN02, SDA,
and XMAP options.
Calculates range (max - min) of a
histogram.
Available with DDM2,
JTA2, ENET, XMATH,
XWAV, CAN02, SDA,
and XMAP options.
Standard in
DDA-5005A, SDA100G,
and sampling scopes.
Standard in
DDA-5005A, SDA100G,
WaveExpert, and
sampling scopes.
194
WM-OM-E Rev I
X-Stream Operator’s Manual
Hist rms
Root mean square of the values in a
histogram.
Available with DDM2,
JTA2, XMATH, XWAV,
CAN02, SDA, and
XMAP options.
Standard in
DDA-5005A, SDA100G,
and sampling scopes
Hist sdev
Standard deviation of values in a
histogram.
Available with DDM2,
JTA2, XMATH, XWAV,
CAN02, SDA, and
XMAP options.
Standard in
DDA-5005A, SDA100G,
WaveExpert, and
sampling scopes.
Hist top
Value of the right-most of the two
most populated histogram peaks.
Available with DDM2,
JTA2, XMATH, XWAV,
CAN02, SDA, and
XMAP options.
Standard in
DDA-5005A, SDA100G,
WaveExpert, and
sampling scopes.
Hist X@peak
The value of the nth highest
histogram peak.
Applies only to
histograms.
Available with JTA2,
XMATH, XWAV,
CAN02, DDM2, SDA,
and XMAP options.
Standard in
DDA-5005A, SDA100G,
and WaveExpert
scopes.
Hold time
Time from the clock edge to the
data edge. You can set levels,
slope, and hysteresis independently
for Hold Clock and Hold Data. See
also Setup parameter.
Reference levels and
edge-transition polarity
can be selected.
Hysteresis argument
used to discriminate
levels from noise in
data.
Available with JTA2,
ENET, USB2, SDA, and
XMAP options.
Standard in SDA100G
scopes.
WM-OM-E Rev I
195
Hparam Script
Visual Basic (or Java) script which
produces a measurement from one
or two input
Available with XMAP,
ASDA, and XDEV
options.
histogram results
Standard in
DDA-5005A.
Jitter Filter
Jitter in the specified frequency
band. Generates a time sequence
of jitter measurements that are
filtered by the selected band-pass
filter.
Available with ASDA
option.
Last
Time from trigger to last (rightmost) Time from trigger to last
cursor.
cursor
Indicates location of
right cursor. Cursors are
interchangeable: for
example, the right
cursor may be moved to
the left of the left cursor
and first will give the
location of the cursor
formerly on the left, now
on right.
Standard parameter.
Level@X
Gives the vertical value at the
specified x position. If the x position
is between two points, it gives the
interpolated value. When the
Nearest point checkbox is
checked, it gives the vertical value
of the nearest data point.
Standard parameter.
Local base
Value of the baseline for a local
feature.
Hysteresis argument
used to discriminate
levels from noise in
data.
Available with DDM2
option.
Standard in
DDA-5005A.
Local bsep
Local baseline separation, between
rising and falling slopes.
Hysteresis argument
used to discriminate
levels from noise in
data.
Available with DDM2
option.
Standard in
DDA-5005A.
196
WM-OM-E Rev I
X-Stream Operator’s Manual
Local max
Maximum value of a local feature.
Hysteresis argument
used to discriminate
levels from noise in
data.
Available with DDM2
option.
Standard in
DDA-5005A.
Local min
Minimum value of a local feature.
Hysteresis argument
used to discriminate
levels from noise in
data.
Available with DDM2
option.
Standard in
DDA-5005A.
Local number
Number of local features
(peak/trough pairs).
Hysteresis argument
used to discriminate
levels from noise in
data.
Available with DDM2
option.
Standard in
DDA-5005A.
Local pkpk
Vertical difference between the
peak and trough of a local feature
(lmax lmin).
Hysteresis argument
used to discriminate
levels from noise in
data.
Available with DDM2
option.
Standard in
DDA-5005A.
Local tbe
Time between events (between
local peak and next trough or local
trough and next peak).
Hysteresis argument
used to discriminate
levels from noise in
data.
Available with DDM2
option.
Standard in
DDA-5005A.
WM-OM-E Rev I
197
Local tbp
Time between a local feature peak
and the next local peak.
Hysteresis argument
used to discriminate
levels from noise in
data.
Available with DDM2
option.
Standard in
DDA-5005A.
Local tbt
Time between a local feature trough
and the next local trough.
Hysteresis argument
used to discriminate
levels from noise in
data.
Available with DDM2
option.
Standard in
DDA-5005A.
Local tmax
Time of the maximum value of a
local feature.
Hysteresis argument
used to discriminate
levels from noise in
data.
Available with DDM2
option.
Standard in
DDA-5005A.
Local tmin
Time of the minimum value of a
local feature.
Hysteresis argument
used to discriminate
levels from noise in
data.
Available with DDM2
option.
Standard in
DDA-5005A.
Local tot
Time a local feature spends over a
user specified percentage of its
peak-to-trough amplitude.
Hysteresis argument
used to discriminate
levels from noise in
data.
Available with DDM2
option.
Standard in
DDA-5005A.
198
WM-OM-E Rev I
X-Stream Operator’s Manual
Local tpt
Time between local feature peak
and trough.
Hysteresis argument
used to discriminate
levels from noise in
data.
Available with DDM2
option.
Standard in
DDA-5005A.
Local ttp
Time between local feature trough
and the next local peak.
Hysteresis argument
used to discriminate
levels from noise in
data.
Available with DDM2
option.
Standard in
DDA-5005A.
Local tut
Time a local feature spends under a
user specified percentage of its
peak-to-trough amplitude.
Hysteresis argument
used to discriminate
levels from noise in
data.
Available with DDM2
option.
Standard in
DDA-5005A.
Mathcad
Produces a parameter using a
user-specified Mathcad function.
Available with XMAP
and XDEV option.
Standard in
DDA-5005A.
Mathcad 2001i or later
must be loaded on the
instrument.
MATLAB
Produces a parameter using a
user-specified MATLAB function.
Available with XMAP
and XDEV option.
Standard in
DDA-5005A,
WaveRunner 6000A,
WaveMaster, WavePro
7000A, and sampling
scopes
MATLAB must be
loaded on the
instrument.
WM-OM-E Rev I
199
Maximum
Measures highest point in
waveform. Unlike top, does not
assume waveform has two levels.
Highest value in waveform
between cursors
Gives similar result
when applied to time
domain waveform or
histogram of data of
same waveform. But
with histograms, result
may include
contributions from more
than one acquisition.
Computes horizontal
axis location of
rightmost non-zero bin
of histogram -- not to be
confused with maxp.
Standard parameter.
Mean
Average of data for time domain
Average of data
waveform. Computed as centroid of
distribution for a histogram.
Gives similar result
when applied to time
domain waveform or
histogram of data of
same waveform. But
with histograms, result
may include
contributions from more
than one acquisition.
Standard parameter.
Median
The average of base and top
values.
Average of Base and Top.
Standard parameter.
Minimum
Measures the lowest point in a
waveform. Unlike base, does not
assume waveform has two levels.
Lowest value in waveform
between cursors
Gives similar result
when applied to time
domain waveform or
histogram of data of
same waveform. But
with histograms, result
may include
contributions from more
than one acquisition.
Standard parameter.
Nb phase
Provides a measurement of the
phase at a specific frequency of a
waveform (narrow band).
Available with DDM2,
XMATH, SDA, and
XMAP options.
Standard in DDA-5005A
and SDA100G scopes.
200
WM-OM-E Rev I
X-Stream Operator’s Manual
Nb Power
Provides a measurement of the
power at a specific frequency of a
waveform (narrow band).
Available with DDM2,
XMATH, PMA2, SDA,
and XMAP options.
Standard in DDA-5005A
and SDA100G scopes.
N-cycle jitter
Peak-to-peak jitter between edges Compares the expected time Available in SDA
spaced n UI apart.
to the actual time of leading analyzers.
edges n bits apart.
NLTS
Provides a measurement of the
nonlinear transition shift for a prml
signal.
Available with DDM2
option.
Num Points
Number of points in the waveform
between the cursors.
Standard parameter.
One Level
One level of an eye diagram
Available with SDA and
SDM options.
Standard in
DDA-5005AA.
Standard in SDA,
SDA100G, and
WaveExpert scopes.
Overshoot-
Overshoot negative: Amount of
(base - min.)/ampl x 100
overshoot following a falling edge,
as percentage of amplitude.
Waveform must contain
at least one falling edge.
On signals not having
two major levels
(triangle or saw-tooth
waves, for example),
may not give predictable
results.
Standard parameter.
Overshoot+
Overshoot positive: Amount of
overshoot following a rising edge
specified as percentage of
amplitude.
Overwrite
Ratio of residual-to-original power
of a low frequency waveform
overwritten by a higher frequency.
WM-OM-E Rev I
(max. - top)/ampl x 100
Waveform must contain
at least one rising edge.
On signals not having
two major levels
(triangle or saw-tooth
waves, for example),
may not give predictable
results.
Standard parameter.
Available with DDM2
option.
Standard in
DDA-5005A.
201
Param Script
Visual Basic or Java script that
produces a measurement from one
or two input waveforms.
Available with XMAP,
XDEV, and ASDA
options.
Standard in
DDA-5005A.
Peak Mag
Peak mag away from a baseline.
Note: the measure gate must
include more of the baseline than
any other single level.
Available with ENET
option.
Peaks
Number of peaks in a histogram.
Available with DDM2,
JTA2, XMATH, XWAV,
CAN02, SDA, and
XMAP options.
Standard in
DDA-5005A, SDA100G,
and WaveExpert
scopes.
Peak to peak
Peak-to-peak: Difference between maximum - minimum
highest and lowest points in
waveform. Unlike ampl, does not
assume the waveform has two
levels.
Gives a similar result
when applied to time
domain waveform or
histogram of data of the
same waveform. But
with histograms, result
may include
contributions from more
than one acquisition.
Standard parameter.
Percentile
Horizontal data value that divides a
histogram so the population to the
left is xx% of the total.
Available with DDM2,
JTA2, XMATH, XWAV,
CAN02, SDA, and
XMAP options.
Standard in
DDA-5005A, SDA100G,
WaveExpert, and
sampling scopes.
Per DCD
Amount of jitter due to duty cycle
distortion
Standard in SDA and
WaveExpert scopes.
Per Duty Cyc
Duty cycle measured on a
persistence
Standard in SDA and
WaveExpert scopes.
202
WM-OM-E Rev I
X-Stream Operator’s Manual
Period
Standard parameter.
Period of a cyclic signal measured
as time between every other pair of
50% crossings. Starting with first
transition after left cursor, period is
measured for each transition pair,
with values averaged to give final Where: Mr is the number of
leading edges found, Mf the
result.
number of trailing edges
the time when
found,
rising edge i crosses the x%
level, and
the time when
falling edge i crosses the x%
level.
Period@level
Period at a specified level and slope
for every cycle in waveform.
Reference levels and
edge-transition polarity
can be selected.
Hysteresis argument
used to discriminate
levels from noise in
data.
Available with JTA2,
AORM, ENET, SDA,
and XMAP options.
Standard in
DDA-5005A, SDA100G,
and WavePro 7000A
scopes.
Per Pulse Sym
Symmetry of RZ pulse around eye
aperture center
Standard in SDA and
WaveExpert scopes.
Persist Area
Area under mean persistence trace
Standard in SDA and
WaveExpert scopes.
Persist Max
Highest vertical value of input
persistence
Standard in SDA and
WaveExpert scopes.
Persist Mean
Average of persistence data
Standard in SDA and
WaveExpert scopes.
Persist Mid
Mid level between Maximum and
Minimum data
Standard in SDA and
WaveExpert scopes.
Persist Min
Lowest vertical value of input
persistence
Standard in SDA and
WaveExpert scopes.
Persist PkPk
Difference between maximum and
minimum data values
Standard in SDA and
WaveExpert scopes.
Persist RMS
Root mean square of persistence
data
Standard in SDA and
WaveExpert scopes.
WM-OM-E Rev I
203
Phase
Phase difference between signal
analyzed and signal used as
reference. You can set the output
type to percent, degrees, or
radians. After setting up the
reference, touch the More tab for
signal setups.
Phase difference between
signal and reference
Standard parameter.
Pj
Periodic component of jitter
Available with SDA
option.
Power Factor
Ratio of real to apparent power
Available with PMA2
option.
PW50
Average pulse width at the 50%
point between the local baseline
and the local peak or trough.
Hysteresis argument
used to discriminate
levels from noise in
data.
Available with DDM2
option.
Standard in
DDA-5005A.
PW50-
Average pulse width at the 50%
point between the local baseline
and the local trough.
Hysteresis argument
used to discriminate
levels from noise in
data.
Available with DDM2
option.
Standard in
DDA-5005A.
PW50+
Average pulse width at the 50%
point between the local baseline
and the local peak.
Hysteresis argument
used to discriminate
levels from noise in
data.
Available with DDM2
option.
Standard in
DDA-5005A.
Real Power
204
Mean of the product of voltage and
current waveform (or mean of the
instantaneous power)
Available with PMA2
option.
WM-OM-E Rev I
X-Stream Operator’s Manual
Resolution
Ratio of taa for a high and low
frequency waveform
taa (HF)/mean taa (LF)*100 Hysteresis argument
used to discriminate
levels from noise in
data.
Available in DDM2.
Standard in
DDA-5005A.
Ring
Ringback (high or low)
Available with SDA
parameter.
Rj Effective
Amount of random jitter (estimated)
in a signal
Available with SDA
parameter.
Rise
Rise time: Duration of rising edge
from 10-90%.
Time at lower threshold
minus
Time at upper threshold
averaged over each rising
edge
Threshold arguments specify two
vertical values on each edge used
to compute rise time.
On signals not having
two major levels
(triangle or saw-tooth
waves, for example), top
and base can default to
maximum and
minimum, giving,
however, less
predictable results.
Standard parameter.
Formulas for upper and lower
values:
lower = lower thresh. x amp/100 +
base
upper = upper thresh. x amp/100 +
base
Rise 20-80%
Rise 20% to 80%: Duration of pulse Average duration of rising
waveform's rising transition from
20-80% transition
20% to 80%, averaged for all rising
transitions between the cursors.
On signals not having
two major levels
(triangle or saw-tooth
waves, for example), top
and base can default to
maximum and
minimum, giving,
however, less
predictable results.
Standard parameter.
Rise@level
WM-OM-E Rev I
Rise at level: Duration of pulse
waveform's rising edges between
transition levels.
Slew rate for % or absolute On signals not having
levels of rising or falling
two major levels
edges.
(triangle or saw-tooth
waves, for example), top
Enhanced version sets
measurement calculations to and base can default to
maximum and
use one of the following:
minimum, giving,
205
Base & Top (% or absolute) however, less
predictable results.
Peak-Peak (%)
Standard parameter.
0V-Max (%)
Enhanced parameter
available with EMC
option.
Gives similar result
when applied to time
domain waveform or
histogram of data of
same waveform. But
with histograms, result
Where: vi denotes measured may include
contributions from more
sample values, and N =
number of data points within than one acquisition.
the periods found up to
Standard parameter.
maximum of 100 periods.
RMS
Root Mean Square of data between
the cursors -- about same as sdev
for a zero-mean waveform.
SAS
Signal Amplitude Symmetry of a
100Base-T signal
Available with ENET
option.
SD2Skew
Calculates the time skew between 2
serial data lanes
Available with SDA and
PCIE options.
Setup
Time from the data edge to the
clock edge.
Reference levels and
edge-transition polarity
can be selected.
Hysteresis argument
used to discriminate
levels from noise in
data.
Available with JTA2 and
XMAP options.
Standard in SDA and
SDA100G scopes.
Skew
206
Time of clock1 edge minus time of
nearest clock2 edge.
Reference levels and
edge-transition polarity
can be selected.
Hysteresis argument
used to discriminate
levels from noise in
data. Hysteresis on a
measurement (if set to
500 mdiv) requires that
the signal must
transition one way 1/2
division (total swing)
across the threshold for
the measurement to be
WM-OM-E Rev I
X-Stream Operator’s Manual
valid.
Available with JTA2 and
XMAP options.
Standard in SDA100G
and WaveSurfer
scopes.
Slew Rate
Slew rate or local dV/dt in a
transition zone
Available in SDA and
JTA2 options.
Standard in SDA100G
scopes.
SSC Diff
Calculates difference between
average SSC frequencies.
Available with PCIE
option.
SSC Frequency Frequency of Spread Spectrum
Clock signal.
Available with PCIE
option.
SSC Ratio
Calculates the ratio between the
maximum and minimum SSC
frequencies.
Available with PCIE
option.
SSC Track
Tracks Spread Spectrum Clock.
Filtered track of frequency at level.
Available with ASDA
option.
Std dev
Standard deviation of the data
between the cursors -- about the
same as rms for a zero-mean
waveform.
Gives similar result
when applied to time
domain waveform or
histogram of data of
same waveform. But
with histograms, result
may include
contributions from more
than one acquisition.
Where: vi denotes
measured sample
values, and N = number
of data points within the
periods found up to
maximum of 100
periods.
Standard parameter.
TAA
Average peak-to-trough amplitude
for all local features.
Hysteresis argument
used to discriminate
levels from noise in
data.
Available with DDM2
option.
Standard in
WM-OM-E Rev I
207
DDA-5005A.
TAA-
Average local baseline-to-trough
amplitude for all local features.
Hysteresis argument
used to discriminate
levels from noise in
data.
Available with DDM2
option.
Standard in
DDA-5005A.
TAA+
Average local baseline-to-peak
amplitude for all local features.
Hysteresis argument
used to discriminate
levels from noise in
data.
Available with DDM2
option.
Standard in
DDA-5005A.
TIE@level
Difference between the measured Cutoff Freq = (1/1.667e3) x
times of crossing a given slope and Clock Freq
level and the ideal expected time.
For Slope you can choose positive,
negative, or both. For output units
you can choose time or unit interval
(UI). A unit interval equals one clock
period.
The Virtual Clock setup gives you a
choice of Standard (1.544 MHz) or
Custom reference clocks.
You can also use a mathematically
derived Golden PLL to filter low
frequency jitter. The cutoff
frequency is user selectable.
Reference levels and
edge-transition polarity
can be selected.
Hysteresis argument
used to discriminate
levels from noise in
data.
Available with JTA2,
ENET, SDA, and XMAP
options.
Standard in SDA100G,
WavePro 7000A,
WaveExpert, and
sampling scopes.
Time@edge
Measures time at each edge on
each digital line
Available with MS-32
option.
Time@level
Time at level: Time from trigger
Time from trigger to crossing Reference levels and
(t=0) to crossing at a specified level. level
edge-transition polarity
can be selected.
Hysteresis argument
used to discriminate
levels from noise in
data.
Standard parameter.
Top
208
Higher of two most probable states, Value of most probable
the lower being base; it is
higher state
Gives similar result
when applied to time
WM-OM-E Rev I
X-Stream Operator’s Manual
characteristic of rectangular
waveforms and represents the
higher most probable state
determined from the statistical
distribution of data point values in
the waveform.
domain waveform or
histogram of data of
same waveform. But
with histograms, result
may include
contributions from more
than one acquisition.
Standard parameter.
Total Jitter
Total jitter at a given bit error rate
Available with ENET
and SDA options.
Total Pop
Total population of a histogram.
Available with DDM2,
JTA2, XMATH, XWAV,
CAN02, SDA, and
XMAP options.
Standard in
DDA-5005A, SDA100G,
WaveExpert, and
sampling scopes
tUpS
Upsamples a time parameter by nX
Available with SDA and
SDM options.
TxCmD
PCI Express: V
TX-CM-DC-LINE-DELTA
Available with PCIE
option.
Absolute delta of DC common
mode voltage between D+ and DTxFall
Fall2080 and ParamRescale, to get
UI
Available with PCIE
option.
TxRise
Rise2080 and ParamRescale, to
get UI
Available with PCIE
option.
Vcross
Voltage at which two signals cross.
That is, voltage of either signal at
the time when difference is zero.
Available with SDA and
PCIE options.
Vdiff
Used for V TX-DIFFp-p and V
RX-DIFFp-p for PCI-Express
Available with PCIE
option.
VTxDeRatio
Ratio between transition and
de-emphasized bits
Available with PCIE
option.
Width
Width of cyclic signal determined by Width of first positive or
examining 50% crossings in data negative pulse averaged for
input. If first transition after left
all similar pulses
cursor is a rising edge, waveform is
considered to consist of positive
pulses and width the time between
adjacent rising and falling edges.
Conversely, if falling edge, pulses
are considered negative and width
Similar to fwhm, though,
unlike width, that
parameter applies only
to histograms.
WM-OM-E Rev I
Standard parameter.
209
the time between adjacent falling
and rising edges. For both cases,
widths of all waveform pulses are
averaged for the final result.
Width@level
Width measured at a specific level. Time between two
transitions of opposite slope
at a specified level. (Slope
specified for 1st transition.)
Reference levels and
edge-transition polarity
can be selected.
Hysteresis argument
Enhanced version sets
used to discriminate
measurement calculations to levels from noise in
use one of the following:
data.
Base & Top (% or absolute) Available with JTA2,
Peak-Peak (%)
0V-Max (%)
0V-Min (%)
USB2, EMC, SDA, and
XMAP options.
Standard in SDA100G
and WavePro 7000A
scopes.
Enhanced parameter
available with EMC
option.
WidthN
Width measured at the 50% level
and negative slope.
Standard parameter.
X@max
Determines the horizontal axis
location of the maximum value
between the cursors.
Restricted to time and
frequency waveforms
only.
X@min
Determines the horizontal axis
location of the minimum value
between the cursors.
Restricted to time and
frequency waveforms
only.
Zero Level
Zero level of an eye diagram
Available with SDA and
SDM options.
Standard in SDA,
SDA100G, and
WaveExpert scopes.
210
WM-OM-E Rev I
X-Stream Operator’s Manual
Qualified Parameters
Some LeCroy instruments and software packages give you the capability to constrain parameter
measurements to a vertically or horizontally limited range, or to occurrences gated by a second
waveform. Furthermore, both constraints can operate together. This capability enables you to
exclude unwanted characteristics from your measurements. It is much more restrictive than
Measure Gate, which is used only to narrow the span of the waveform for analysis, along the
horizontal axis.
Range Limited Parameters
To Set Up Range Qualifiers
1. From the menu bar, select Measure, then Measure Setup... from the drop-down menu.
2. Touch a Px tab to open the setup dialog.
3. Touch inside the Source field and select a source from the pop-up menu.
4. Touch inside the Measure field and select a parameter from the pop-up menu.
5. Touch the Accept tab of the right-hand dialog, then touch the Values In Range checkbox.
Depending on whether you select a vertical or horizontal parameter, the correct units will
be automatically displayed (V, s, Hz, dB) in the Between and And fields. Or, if you select a
simple ratio parameter (such as power factor) which yields a dimensionless number, no
units will be displayed.
6. Touch the Find Range button to quickly display the most recent value of the parameter
measurement. From there it is a simple matter to set the desired range.
Amplitude Parameter
(range set manually)
WM-OM-E Rev I
211
Delay Parameter
(Find Range selected)
212
WM-OM-E Rev I
X-Stream Operator’s Manual
Waveform Gated Parameters
To Set Up Waveform Qualifiers
1. From the menu bar, select Measure, then Measure Setup... from the drop-down menu.
2. Touch a Px tab to open the setup dialog.
3. Touch inside the Source field and select a source from the pop-up menu.
4. Touch inside the Measure field and select a parameter from the pop-up menu.
5. Touch the Accept tab of the right-hand dialog, then touch the Values Based on
Waveform State checkbox.
6. Touch inside the When Wform field and select the gating source.
7. Touch inside the State Is field and select High or Low from the pop-up menu. Parameter
measurements on the subject waveform will only be taken when the gating waveform is in
the selected state.
8. Touch inside the Level Type field and select Absolute or Percent from the pop-up menu.
9. Touch inside the Level field and enter the crossing level value at which you want
measurements to begin. Alternatively, touch the Find Level button to automatically select
the 50% level of your gating waveform:
WM-OM-E Rev I
213
WAVEFORM MATH
Introduction to Math Traces and Functions
With the instrument’s math tools you can perform mathematical functions on a waveform displayed
on any channel, or recalled from any of the four reference memories M1 to M4. You can also set up
traces F1 to Fx [The number of math functions that can be performed at the same time depends on
the software options loaded on your scope.] to do math on parameter measurements P1 to Px [The
number of parameters that can be measured at the same time depends on the software options
loaded on your scope.].
For example: you could set up Trace F1 as the difference between Channels 1 and 2, Trace F2 as
the average of F1, and Trace F3 as the integral of F2. You could then display the integral of the
averaged difference between Channels 1 and 2. Any trace and function can be chained to another
trace and function. For example, you could make Trace F1 an average of Channel 1, Trace F2 an
FFT of F1, and Trace F3 a zoom of F2.
Note: Math traces F5-F8 are available only if you have loaded software option package XMATH or XMAP on WaveMaster or
WavePro scopes, but are standard on Disk Drive Analyzers and Serial Data Analyzers.
Math Made Easy
With the instrument's math tools you can perform mathematical functions on a waveform displayed
on any channel C1 to C4, or recalled from any of the four reference memories M1 to M4. To do
computations in sequence, you can also use math functions F1 to Fx as a source input waveform.
Or you can use Parameters P1 through Px
For example: you could set up F1 as the difference between Channels 1 and 2, F2 as the average
of F1, and F3 as the integral of F2. You could then display the integral of the averaged difference
between Channels 1 and 2. Any trace and function can be chained to another trace and function.
For example, you could make F1 an average of Channel 1, F2 an FFT of F1, and F3 a zoom of F2.
Refer to the Specifications to find out which math tools are available in each optional package.
To Set Up a Math Function
Math Setup
This setup mode allows you to quickly apply frequently used math functions.
1. In the menu bar, touch Math, then Math setup...
2. If there are math functions already assigned to F1 through Fx [The number of math traces
available depends on the software options loaded on your scope. See specifications.],
touch the checkbox for the function you want to enable.
3. To assign a new math function to a trace, touch the Fx button for that trace, for example
. The math function menu appears.
4. Touch a menu selection; your new function is automatically assigned, with the same
setups as were in place for the last function in that Fx position.
5. If you want to change other setup items, like the source waveform, touch the appropriate
214
WM-OM-E Rev I
X-Stream Operator’s Manual
Fx tab, for example
. The setup dialog for that Fx position appears.
6. Touch the Single function button
if you want to perform just one math function on
the trace, or touch the Dual function button
to perform math on math.
7. Touch the Graph button, then touch inside the Graph with field to select a graph mode.
The Graph modes are as follows:
Histogram of the values of a parameter
Track of the values of a parameter
Trend of the values of a parameter
Resampling To Deskew
Deskew whenever you need to compensate for different lengths of cables, probes, or anything else
that might cause timing mismatches between signals. Resample a signal on one channel and
adjust it in time relative to a signal on another channel.
To Resample
1. In the menu bar, touch Math, then Math Setup... in the drop-down menu.
2. Touch a math function trace tab F1 through Fx The number of math traces available
depends on the software options loaded on your scope. See Specifications..
3. Touch the single function button.
4. Touch inside the Source1 field and select a source: channel, math trace, memory location.
5. Touch inside the Operator1 field and select Deskew from the Functions category.
6. In the dialog on the right, touch the Deskew tab.
7. Touch inside the Delay by data entry field and type in a time value, using the pop-up
keypad.
WM-OM-E Rev I
215
Rescaling and Assigning Units
This feature allows you to apply a multiplication factor (a) and additive constant (b) to your
waveform: aX + b. You can do it in the unit of your choice, depending on the type of application.`
To Set Up Rescaling
1. In the menu bar, touch Math, then Math Setup... in the drop-down menu.
2. Touch a math function trace tab F1 through Fx The number of math traces available
depends on the software options loaded on your scope. See Specifications..
3. Touch the single function button.
4. Touch inside the Source1 data entry field and select a source: channel, math trace,
memory location.
5. Touch inside the Operator1 data entry field and select Rescale from the Functions
category.
6. In the dialog on the right, touch the Rescale tab.
7. Touch inside the First multiply by checkbox and enter a value for a, the multiplication
factor.
8. Touch inside the then add: data entry field and enter a value for b, the additive constant.
9. Touch inside the Override units checkbox to disregard the source waveform's units, using
the pop-up keyboard.
Averaging Waveforms
Summed vs. Continuous Averaging
For Summed averaging, you specify the number of acquisitions to be averaged. The averaged data
is updated at regular intervals and presented on the screen.
On the other hand, Continuous averaging (the system default) helps to eliminate the effects of
noise by continuously acquiring new data and adding the new waveforms into the averaging buffer.
You determine the importance of new data vs. old data by assigning a weighting factor. Continuous
averaging allows you to make adjustments to a system under test and to see the results
immediately.
Note: Continuous Averaging is accessible from the channel "Vertical Adjust" dialog under "Pre-Processing," and from the
math function menu.
Summed Averaging
Summed Averaging is the repeated addition, with equal weight, of successive source waveform
records. If a stable trigger is available, the resulting average has a random noise component lower
than that of a single-shot record. Whenever the maximum number of sweeps is reached, the
averaging process stops.
An even larger number of records can be accumulated simply by changing the number in the dialog.
However, the other parameters must be left unchanged or a new averaging calculation will be
started. You can pause the averaging by changing the trigger mode from NORM/AUTO to STOP.
216
WM-OM-E Rev I
X-Stream Operator’s Manual
The instrument resumes averaging when you change the trigger mode back to NORM/AUTO.
You can reset the accumulated average by pushing the CLEAR SWEEPS button or by changing an
acquisition parameter such as input gain, offset, coupling, trigger condition, timebase, or bandwidth
limit. The number of current averaged waveforms of the function, or its zoom, is shown in the
acquisition status dialog. When summed averaging is performed, the display is updated at a
reduced rate to increase the averaging speed (points and events per second).
Continuous Averaging
Continuous Averaging, the default setting, is the repeated addition, with unequal weight, of
successive source waveforms. It is particularly useful for reducing noise on signals that drift very
slowly in time or amplitude. The most recently acquired waveform has more weight than all the
previously acquired ones: the continuous average is dominated by the statistical fluctuations of the
most recently acquired waveform. The weight of ‘old’ waveforms in the continuous average
gradually tends to zero (following an exponential rule) at a rate that decreases as the weight
increases.
The formula for continuous averaging is
new average = (new data + weight * old average)/(weight + 1)
This is also the formula used to compute summed averaging. But by setting a "sweeps" value, you
establish a fixed weight that is assigned to the old average once the number of "sweeps" is reached.
For example, for a sweeps (weight) value of 4:
1st sweep (no old average yet): new average = (new data +0 * old average)/(0 + 1) = new
data only
2nd sweep: new average = (new data + 1*old average)/(1 + 1) = 1/2 new data +1/2 old
average
3rd sweep: new average = (new data + 2 * old average)/(2 + 1) = 1/3 new data + 2/3 old
average
4th sweep: new average = (new data + 3 * old average)/(3 + 1) = 1/4 new data + 3/4 old
average
5th sweep: new average = (new data + 4 * old average)/(4 + 1) = 1/5 new data + 4/5 old
average
6th sweep: new average = (new data + 4 * old average)/(4 + 1) = 1/5 new data + 4/5 old
average
7th sweep: new average = (new data + 4 * old average)/(4 + 1) = 1/5 new data + 4/5 old
average
In this way, for sweeps > 4 the importance of the old average begins to decrease exponentially.
Note: The number of sweeps used to compute the average will be displayed in the bottom line of the trace descriptor label:
WM-OM-E Rev I
217
To Set Up Continuous Averaging
1. In the menu bar, touch Math, then Math Setup... in the drop-down menu.
2. Select a function tab from F1 through Fx [The number of math traces available depends on
the software options loaded on your scope. See Specifications.].
3. Touch inside the Source1 field and select a source waveform from the pop-up menu.
4. Touch inside the Operator1 field and select Average from the Select Math Operator
menu.
5. Touch the Average tab in the dialog to the right of the "Fx" dialog, touch the Continuous
button.
6. Touch inside the Sweeps data entry field and enter a value using the pop-up keypad. The
valid range is 1 to 1,000,000 sweeps.
To Set Up Summed Averaging
1.
In the menu bar, touch Math, then Math Setup... in the drop-down menu.
2.
Select a function tab from F1 through Fx [The number of math traces available depends on
the software options loaded on your scope. See Specifications.].
3.
Touch inside the Source1 field and select a source waveform from the pop-up menu.
4.
Touch inside the Operator1 field and select Average from the Select Math Operator
menu.
5.
Touch the Average tab in the dialog to the right of the "Fx" dialog, then touch the Summed
button.
6.
Touch inside the Sweeps data entry field and type in a value using the pop-up keypad. The
valid range is 1 to 1,000,000 sweeps.
Enhanced Resolution
ERES (Enhanced Resolution) filtering increases vertical resolution, allowing you to distinguish
closely spaced voltage levels. The functioning of the instrument's ERES is similar to smoothing the
signal with a simple, moving-average filter. However, it is more efficient concerning bandwidth and
pass-band filtering. Use ERES on single-shot waveforms, or where the data record is slowly
repetitive (when you cannot use averaging). Use it to reduce noise when your signal is noticeably
noisy, but you do not need to perform noise measurements. Also use it when you perform
high-precision voltage measurements: zooming with high vertical gain, for example.
How the Instrument Enhances Resolution
The instrument's enhanced resolution feature improves vertical resolution by a fixed amount for
each filter. This real increase in resolution occurs whether or not the signal is noisy, or your signal is
single-shot or repetitive. The signal-to-noise ratio (SNR) improvement you gain is dependent on the
form of the noise in the original signal. The enhanced resolution filtering decreases the bandwidth
of the signal, filtering out some of the noise.
The instrument's constant phase FIR (Finite Impulse Response) filters provide fast computation,
218
WM-OM-E Rev I
X-Stream Operator’s Manual
excellent step response in 0.5 bit steps, and minimum bandwidth reduction for resolution
improvements of between 0.5 and 3 bits. Each step corresponds to a bandwidth reduction factor of
two, allowing easy control of the bandwidth resolution trade-off. The parameters of the six filters are
given in the following table.
Resolution
-3 dB Bandwidth
Filter Length
increased by
(× Nyquist)
(Samples)
0.5
0.5
2
1.0
0.241
5
1.5
0.121
10
2.0
0.058
24
2.5
0.029
51
3.0
0.016
117
With low-pass filters, the actual SNR increase obtained in any particular situation depends on the
power spectral density of the noise on the signal.
The improvement in SNR corresponds to the improvement in resolution if the noise in the signal is
white -- evenly distributed across the frequency spectrum.
If the noise power is biased towards high frequencies, the SNR improvement will be better than the
resolution improvement.
The opposite may be true if the noise is mostly at lower frequencies. SNR improvement due to the
removal of coherent noise signals -- feed-through of clock signals, for example -- is determined by
the fall of the dominant frequency components of the signal in the passband. This is easily
ascertained using spectral analysis. The filters have a precisely constant zero-phase response.
This has two benefits. First, the filters do not distort the relative position of different events in the
waveform, even if the events' frequency content is different. Second, because the waveforms are
stored, the delay normally associated with filtering (between the input and output waveforms) can
be exactly compensated during the computation of the filtered waveform.
The filters have been given exact unity gain at low frequency. Enhanced resolution should therefore
not cause overflow if the source data is not overflowed. If part of the source trace were to overflow,
filtering would be allowed, but the results in the vicinity of the overflowed data -- the filter impulse
response length -- would be incorrect. This is because in some circumstances an overflow may be
a spike of only one or two samples, and the energy in this spike may not be enough to significantly
affect the results. It would then be undesirable to disallow the whole trace.
The following examples illustrate how you might use the instrument's enhanced resolution function.
WM-OM-E Rev I
219
In low-pass filtering: The spectrum of a square signal
before (left top) and after (left bottom) enhanced resolution
processing. The result clearly illustrates how the filter
rejects high-frequency components from the signal. The
higher the bit enhancement, the lower the resulting
bandwidth.
To increase vertical resolution: In the example at left, the
lower ("inner") trace has been significantly enhanced by a
three-bit enhanced resolution function.
To reduce noise: The example at left shows enhanced
resolution of a noisy signal. The original trace (left top) has
been processed by a 2-bit enhanced resolution filter. The
result (left bottom) shows a "smooth" trace, where most of
the noise has been eliminated.
220
WM-OM-E Rev I
X-Stream Operator’s Manual
Note: Enhanced resolution can only improve the resolution of a trace; it cannot improve the accuracy or linearity of the
original quantization. The pass-band will cause signal attenuation for signals near the cut-off frequency. The highest
frequencies passed may be slightly attenuated. Perform the filtering on finite record lengths. Data will be lost at the start and
end of the waveform: the trace will be slightly shorter after filtering. The number of samples lost is exactly equal to the length
of the impulse response of the filter used: between 2 and 117 samples. Normally this loss (just 0.2 % of a 50,000 point trace)
is not noticed. However, you might filter a record so short there would be no data output. In that case, however, the
instrument would not allow you to use the ERES feature.
To Set Up Enhanced Resolution (ERES)
1. In the menu bar, touch Math, then Math Setup... in the drop-down menu.
2. Touch a function tab F1 through Fx. (The number of math traces available depends on the
software options loaded on your scope. See Specifications.)
3. Touch inside the Operator1 data entry field.
4. Select ERES from the All Functions or Filter group of Math functions.
5. Touch the Trace On checkbox.
6. Touch the "ERES" tab in the right-hand dialog, then touch inside the bits field and make an
"Enhance by" selection from the pop-up menu:
.
Waveform Copy
The Copy math function
makes a copy of your present waveform in its unprocessed state.
While processing may continue on the original waveform, the copy enables faster throughput in
some cases by preserving the original data. That is, no calculations need to be undone on the copy
before additional math can be calculated.
This benefit of faster throughput, however, comes at the expense of memory usage.
Waveform Sparser
The Sparse math function
allows you to thin out an incoming waveform by skipping
points at regular intervals, and by starting acquisition at a particular "offset" (point). The Sparsing
factor specifies the number of sample points to reduce the input waveform by. A sparsing factor of
4, for example, tells the scope to retain only one out of every 4 samples. A Sparsing offset of 3, on
WM-OM-E Rev I
221
the other hand, tells the scope to begin on the third sample, then skip the number of samples
specified by the sparsing factor (4). In this way, the sample rate is effectively reduced.
For the sparsing factor (interval), you can set a value from 1 to 1,000,000 points. For the sparsing
offset you can set a value from 0 to 999,999.
Note: The maximum sparsing offset that can be entered for any sparsing factor equals Sparsing Factor 1.
To Set Up Waveform Sparser
1. In the menu bar, touch Math, then Math setup... in the drop-down menu.
2. Touch the tab for the function (F1 to Fx The number of math traces available depends on
the software options loaded on your scope. See specifications.) you want to assign the
Sparse operation to.
3. Touch inside the Source1 field and select an input waveform.
4. Touch inside the Operator1 field and select Sparse from the Select Math Operator menu.
5. Touch inside the Sparsing factor field and enter a value, using the pop-up keypad.
6. Touch inside the Sparsing offset field and enter a value, using the pop-up keypad.
Interpolation
Linear interpolation, which inserts a straight line between sample points, is best used to reconstruct
straight-edged signals such as square waves. (Sinx)/x interpolation, on the other hand, is suitable
for reconstructing curved or irregular waveshapes, especially when the sampling rate is 3 to 5 times
the system bandwidth. The instrument also gives you a choice of Cubic interpolation.
For each method, you can select a factor from 2 to 50 points by which to interpolate (upsample).
To Set Up Interpolation
1. In the menu bar, touch Math, then Math setup... in the drop-down menu.
2. Touch the tab for the function (F1 to Fx The number of math traces available depends on
the software options loaded on your scope. See Specifications.) you want to assign the
Interpolate operation to.
3. Touch inside the Source1 field and select an input waveform.
4. Touch inside the Operator1 field, then touch the Filter button in the Select Math Operator
menu.
5. Select Interpolate from the Filter submenu.
6. Touch the "Interpolate" tab in the mini setup dialog to the right of the main dialog.
7. Touch inside the Algorithm field and select an interpolation type.
8. Touch inside the Upsample by Upsampling is the factor by which sampling is increased.
field and enter a value, using the pop-up numeric keypad, if you want to enter a specific
value. Otherwise, use the Up/Down buttons to increment the displayed value in a 1-2-5
sequence.
222
WM-OM-E Rev I
X-Stream Operator’s Manual
Fast Wave Port
FastWavePort is a processing function for the LeCroy X-Stream family of digital oscilloscopes that
enables you to insert your own custom processing algorithm, written in the C/C++ language, into
the scope's processing stream. FastWavePort maximizes data throughput from the acquisition
system to your processing function. It also makes it simple to create these custom processing
functions.
The technology that makes this system possible is the ability of two processes in a Windows
system to share a region of memory. This enables the transfer of data at high-speed between the
acquisition software and the custom processing function, which runs in a separate process from the
scope application. A major benefit of FastWavePort is that your application may be implemented
and, more importantly, debugged independently of the main application.
It is important to note that the transfer of the results of your processing function back into the
X-Stream processing stream is optional. If performance is the primary goal, and display or further
processing of the results within the scope software is not required, then this may be skipped.
Fast Wave Port Setup -- Initial
1. In the menu bar, touch Math, then Math Setup... in the drop-down menu.
2. Touch one of the Math function tabs,
for example.
3. Touch inside the "Source1" field, and select a signal source from the pop-up menu. The
source can be a channel waveform, math or memory trace, or a parameter.
4. Touch inside the "Operator"1 field and select FastWavePort
menu
WM-OM-E Rev I
from the Custom
223
5. In the right-hand mini-dialog, touch the Fast Wave Port tab:
6. Touch inside the "Timeout" field and enter a suitable value.
Setup -- Case 1
This scenario assumes that you have developed your application on a PC.
1. Compile your application on your PC
2. Copy the compiled file onto the scope, using a memory stick or network drive.
3. Open the Command Prompt window (Start --> Programs --> Accessories --> Command
Prompt) and run your application.
Setup -- Case 2
This scenario assumes that you have Visual C++ loaded on the scope.
•
Use the Visual C++ editor to develop and run your application.
Setup -- Case 3
This scenario assumes that you are using a compiler other than Visual C++ (such as GNU's
MinGW). It should be noted that the optimizer in the GNU C Compiler (GCC) is less efficient than
that in Visual C++ and will result in lower performance.
1. Save your application in a text file, and copy it onto memory stick or network drive.
2. Using Windows Explorer, copy the text file to the scope.
3. Download and install the compiler onto the scope.
4. Configure Environmental Variables as follows:
A. Open Start --> Settings --> Control Panel --> System.
B. Click the "Advanced" tab, then the Environmental Variables button.
C. In the "System variables" window, click Path, then the Edit button.
224
WM-OM-E Rev I
X-Stream Operator’s Manual
D. At the end of the "Variable Value" string, append ;C:\MinGW\bin for the case of the
GNU C Compiler (GCC) for example.
E. Click OK.
5. Open the Command Prompt window (Start --> Programs --> Accessories --> Command
Prompt) and compile your application.
6. Run your application.
Operational Notes
Once FastWavePort is selected, the right-hand dialog shows the current settings. The first of these
is critical, and indicates the base name of the memory window and the two events, which are global
within the Windows O/S. This should be left at its default value and only changed if multiple
FastWavePort functions are used in parallel. Note that this name must match the base name used
in the client application.
The full names of these global objects are:
Memory Mapped File
"FastWavePort1File"
Data Available Event
"FastWavePort1MutexDataAvailable"
Processing Complete Event
"FastWavePort1MutexProcessingComplete"
The "Timeout" field specifies the amount of time that the scope will wait for the custom processing
function to complete. This prevents the scope from waiting indefinitely for a potentially
unforthcoming custom processing function. Be careful to set this value to something reasonable,
which means a time that is longer by a reasonable margin than the custom processing is ever
expected to take.
Example Applications
This simple C++ application may be used as a starting point for a custom processing function. It
demonstrates the following:
•
How to create handles to the global objects (the memory window and the two events)
•
How to read data from the memory window when the scope flags that it's available
•
How to scale the data into units of volts using data in the header that's stored at the
beginning of the memory window.
•
How to perform a simple processing function (in this case the absolute value)
•
How to define the physical units of the output of the processing function (in this case
'Amps')
•
How to flag to the scope application that processing is complete
//----------------------------------------------------------------------------------------// FastWavePortClient.cpp :
//
WM-OM-E Rev I
225
// Prototype C++ client application for "Fast Wave Port' Math Processor
//
// Compatibility:
//
Microsoft Visual C++ 6.0, 7.1
//
MinGW 'gcc' based compiler (free download from http://www.mingw.org/)
//
Compile with: mingw32-c++ -o fastWavePortClient.exe fastwaveportclient.cpp
//----------------------------------------------------------------------------------------#include "windows.h"
#include <stdio.h>
//--------------------------------------------------------------------------------------// FastWavePort header, describes various properties of the waveform passed to the
// user-processing
// function. Also used to carry the properties of the processed waveform back to the
// DSO.
#define FLAGS_OUTPUT_VALID
0x01
typedef unsigned __int64 lecTimeStamp;
lecTimeStamp lecTimeStampOneSecond = 1000000000;
#pragma pack(push, 4)
// 1 ns units in a second
// pack on 4-byte boundaries (Important!)
struct CDescHeader
{
int descVersion;
int flags;
// header version number
// misc. flags indicating the status of input, and
// how to treat the output
int headerSize;
// size of the header, data starts immediately after
// the hdr.
int windowSize;
// total size of the window (header + data)
int numSamples;
// total number of samples in the input waveform
int segmentIndex;
// index of this segment, usually zero when input
// waveform is not a sequence
int numSweeps;
int _dummy1;
double verGain;
// not used
// scale factor that relates integer sample data
//values to the vertical units of the waveform.
double verOffset;
// vertical offset (in vertical units, e.g. Volts) of
// the waveform
double verResolution;
// vertical resolution of the measurement system (also
// in vertical units)
double horInterval;
// scale factor that relates integer sample indices to
// the horizontal units of the waveform.
226
WM-OM-E Rev I
X-Stream Operator’s Manual
double horOffset;
// horizontal offset (in horizontal units, e.g. seconds)
// of the waveform
double horResolution;
// horizontal resolution of the measurement system
//(also in horizontal units)
lecTimeStamp trigTime;
// trigger time, units of 1ns since 00:00:00 on Jan 1st
// 2000, 64-bit unsigned integer
char verUnit[48];
// vertical units of the waveform ("V" for example)
char horUnit[48];
// horizontal units of the waveform ("s" for example)
};
#pragma pack(pop)
// restore packing
//----------------------------------------------------------------------------------------// The buffer size is 80MB (40,000,000 samples, stored as short integers) plus 0x1000
// bytes for the header.
const unsigned long HEADER_SIZE = 0x1000
const unsigned long MEM_MAP_FILE_SIZE = 80000000 + HEADER_SIZE;
// = 40MSamples,
// or 80MBytes
int main(int argc, char* argv[])
{
// names based on 'FastWavePort1' name defined in Processor setup.
char szMapFileName[]
= "FastWavePort1File";
char szMutexDataAvailableName[]
= "FastWavePort1MutexDataAvailable";
char szMutexProcessingCompleteName[]
= "FastWavePort1MutexProcessingComplete";
// Associate shared memory file handle value.
HANDLE m_hMMFile = CreateFileMapping ((HANDLE)0xffffffff, NULL, PAGE_READWRITE, 0,
MEM_MAP_FILE_SIZE, szMapFileName);
if(m_hMMFile == 0)
{
printf("Unable to create file mapping\n");
return 0;
}
// Map a view of this file for writing.
short *m_lpMMFile = (short *)MapViewOfFile (m_hMMFile, FILE_MAP_ALL_ACCESS, 0, 0, 0);
if(m_lpMMFile == 0)
{
printf("Unable to map view of file\n");
return 0;
}
// create/open events used for synchronization
WM-OM-E Rev I
227
// if the client app. was run before the scope then these events will be created,
// if the scope was run first then these events
// will just be opened
HANDLE m_hDataAvailable = CreateEvent(NULL, FALSE, FALSE /* initial state */,
szMutexDataAvailableName);
HANDLE m_hProcessingComplete = CreateEvent(NULL, FALSE, FALSE /* initial state */,
szMutexProcessingCompleteName);
if(m_hDataAvailable == 0 || m_hProcessingComplete == 0)
{
printf("Unable to open events\n");
return 0;
}
// main loop
while(1)
{
int i = 0;
printf("Waiting for new data...\n");
// wait an infinite amount of time for data to be available
DWORD waitSuccess = WaitForSingleObject(m_hDataAvailable, INFINITE);
// print the first few bytes of the input waveform
CDescHeader *descHeader = (CDescHeader *) &m_lpMMFile[0];
short *m_lpWaveform = &m_lpMMFile[descHeader->headerSize / sizeof(short)];
for(i = 0; i < 4; ++i)
printf("%f ", (m_lpWaveform[i] * descHeader->verGain) +
descHeader->verOffset);
// compute the mean of all data values, while computing the abs value of the waveform
//in-place
double sum = 0.0;
for(i = 0; i < descHeader->numSamples; ++i)
{
sum += (m_lpWaveform[i] * descHeader->verGain) + descHeader->verOffset;
m_lpWaveform[i] = abs(m_lpWaveform[i]);
}
sum /= descHeader->numSamples;
// modify the output units, set to Amps
strcpy(descHeader->verUnit, "A");
// print the mean, numer of samples, trigger time in seconds, and the segment index
printf("
(%f) %d %d %d\n", sum, descHeader->numSamples, (int)
(descHeader->trigTime / lecTimeStampOneSecond), descHeader->segmentIndex);
228
WM-OM-E Rev I
X-Stream Operator’s Manual
// use to flag that the output is not valid, increasing performance when
// it is not necessary to read data back into the DSO
//descHeader->flags &= ~FLAGS_OUTPUT_VALID;
// flag that processing is complete
SetEvent(m_hProcessingComplete);
}
return 0;
}
Header Description
int descVersion;
int flags;
// header version number
// misc. flags indicating the status of input, and how
// to treat the output
int headerSize;
// size of the header, data starts immediately after the
// hdr.
int windowSize;
// total size of the window
int numSamples;
// total number of samples in the input waveform
int segmentIndex;
(header + data)
// index of this segment, usually zero when input waveform
// is not a sequence
int numSweeps;
int _dummy1;
double verGain;
// not used
// scale factor that relates integer sample data values
// to the vertical units of the waveform.
double verOffset;
// vertical offset (in vertical units, e.g. Volts) of the
// waveform
double verResolution;
// vertical resolution of the measurement system (also
// in vertical units)
double horInterval;
// scale factor that relates integer sample indices to
// the horizontal units of the waveform.
double horOffset;
// horizontal offset (in horizontal units, e.g. seconds)
// of the waveform
double horResolution; // horizontal resolution of the measurement system
// (also in horizontal units)
lecTimeStamp trigTime; // trigger time, units of 1ns since 00:00:00 on Jan
// 1st 2000, 64-bit unsigned integer
char verUnit[48];
// vertical units of the waveform ("V" for example)
char horUnit[48];
// horizontal units of the waveform ("s" for example)
Data Length Limitations
The size of the memory window is fixed at 80 Mbytes, which equates to 40M samples.
WM-OM-E Rev I
229
Performance
Under optimal conditions, on a scope with a 1.7 GHz Celeron processor, rates of up to 75 MS/s
have been observed. Due to the differences between the acquisition and processing hardware in
each of the X-Stream scopes, this value may vary significantly and therefore cannot be guaranteed.
However, this is by far the fastest way to process data using a user-defined algorithm on an
X-Stream scope.
Choice of Programming Language
The system was designed for use with the C/C++ programming language, and all furnished
examples use this language. It is theoretically possible, however, for the processing to be
implemented in any language that supports Windows named events (Mutex) and can open a
named memory-mapped file. Nevertheless, no guarantee can be given as to the behavior of the
system using anything but C/C++.
FFT
Why Use FFT?
For a large class of signals, you can gain greater insight by looking at spectral representation rather
than time description. Signals encountered in the frequency response of amplifiers, oscillator phase
noise and those in mechanical vibration analysis, for example, are easier to observe in the
frequency domain.
If sampling is done at a rate fast enough to faithfully approximate the original waveform (usually five
times the highest frequency component in the signal), the resulting discrete data series will
uniquely describe the analog signal. This is of particular value when dealing with transient signals
because, unlike FFT, conventional swept spectrum analyzers cannot handle them.
Spectral analysis theory assumes that the signal for transformation is of infinite duration. Since no
physical signal can meet this condition, a useful assumption for reconciling theory and practice is to
view the signal as consisting of an infinite series of replicas of itself. These replicas are multiplied by
a rectangular window (the display grid) that is zero outside of the observation grid.
An FFT operation on an N-point time domain signal can be compared to passing the signal through
a comb filter consisting of a bank of N/2 filters. All the filters have the same shape and width and are
centered at N/2 discrete frequencies. Each filter collects the signal energy that falls into the
immediate neighborhood of its center frequency. Thus it can be said that there are N/2 frequency
bins. The distance in Hz between the center frequencies of two neighboring bins is always the
same: Delta f.
Power (Density) Spectrum
Because of the linear scale used to show magnitudes, lower amplitude components are often
hidden by larger components. In addition to the functions offering magnitude and phase
representations, the FFT option offers power density and power spectrum density functions. These
latter functions are even better suited for characterizing spectra. The power spectrum (V2) is the
square of the magnitude spectrum (0 dBm corresponds to voltage equivalent to 1 mW into 50
ohms.) This is the representation of choice for signals containing isolated peaks --- periodic signals,
for instance.
The power density spectrum (V2/Hz) is the power spectrum divided by the equivalent noise
230
WM-OM-E Rev I
X-Stream Operator’s Manual
bandwidth of the filter associated with the FFT calculation. This is best employed for characterizing
broadband signals such as noise.
Memory for FFT
The amount of acquisition memory available will determine the maximum range (Nyquist
frequency) over which signal components can be observed. Consider the problem of determining
the length of the observation window and the size of the acquisition buffer if a Nyquist rate of 500
MHz and a resolution of 10 kHz are required. To obtain a resolution of 10 kHz, the acquisition time
must be at least:
T = 1/Delta f = 1/10 kHz = 100 ms
For a digital oscilloscope with a memory of 100 kB, the highest frequency that can be analyzed is:
Delta f x N/2 = 10 kHz x 100 kB/2 = 500 MHz
FFT Pitfalls to Avoid
Take care to ensure that signals are correctly acquired: improper waveform positioning within the
observation window produces a distorted spectrum. The most common distortions can be traced to
insufficient sampling, edge discontinuities, windowing or the "picket fence" effect.
Because the FFT acts like a bank of band-pass filters centered at multiples of the frequency
resolution, components that are not exact multiples of that frequency will fall within two consecutive
filters. This results in an attenuation of the true amplitude of these components.
Picket Fence and Scallop
The highest point in the spectrum can be 3.92 dB lower when the source frequency is halfway
between two discrete frequencies. This variation in spectrum magnitude is the picket fence effect.
The corresponding attenuation loss is referred to as scallop loss. LeCroy scopes automatically
correct for the scallop effect, ensuring that the magnitude of the spectra lines correspond to their
true values in the time domain.
If a signal contains a frequency component above Nyquist, the spectrum will be aliased, meaning
that the frequencies will be folded back and spurious. Spotting aliased frequencies is often difficult,
as the aliases may ride on top of real harmonics. A simple way of checking is to modify the sample
rate and observe whether the frequency distribution changes.
Leakage
FFT assumes that the signal contained within the time grid is replicated endlessly outside the
observation window. Therefore if the signal contains discontinuities at its edges,
pseudo-frequencies will appear in the spectral domain, distorting the real spectrum. When the start
and end phase of the signal differ, the signal frequency falls within two frequency cells, broadening
the spectrum.
The broadening of the base, stretching out in many neighboring bins, is termed leakage. Cures for
this are to ensure that an integral number of periods is contained within the display grid or that no
discontinuities appear at the edges. Another is to use a window function to smooth the edges of the
signal.
WM-OM-E Rev I
231
Choosing a Window
The choice of a spectral window is dictated by the signal’s characteristics. Weighting functions
control the filter response shape, and affect noise bandwidth as well as side lobe levels. Ideally, the
main lobe should be as narrow and flat as possible to effectively discriminate all spectral
components, while all side lobes should be infinitely attenuated. The window type defines the
bandwidth and shape of the equivalent filter to be used in the FFT processing.
In the same way as one would choose a particular camera lens for taking a picture, some
experimenting is generally necessary to determine which window is most suitable. However, the
following general guidelines should help.
Rectangular windows provide the highest frequency resolution and are thus useful for estimating
the type of harmonics present in the signal. Because the rectangular window decays as a (sinx)/x
function in the spectral domain, slight attenuation will be induced. Alternative functions with less
attenuation (Flat Top and Blackman-Harris) provide maximum amplitude at the expense of
frequency resolution. Whereas, Hamming and Von Hann are good for general purpose use with
continuous waveforms.
Window Type
Applications and Limitations
Rectangular
These are normally used when the signal is transient (completely contained in
the time-domain window) or known to have a fundamental frequency
component that is an integer multiple of the fundamental frequency of the
window. Signals other than these types will show varying amounts of spectral
leakage and scallop loss, which can be corrected by selecting another type of
window.
Hanning (Von
Hann)
These reduce leakage and improve amplitude accuracy. However, frequency
resolution is also reduced.
Hamming
These reduce leakage and improve amplitude accuracy. However, frequency
resolution is also reduced.
Flat Top
This window provides excellent amplitude accuracy with moderate reduction of
leakage, but with reduced frequency resolution.
Blackman-Harris It reduces the leakage to a minimum, but with reduced frequency resolution.
232
WM-OM-E Rev I
X-Stream Operator’s Manual
FFT Window Filter Parameters
Window Type
Highest Side
Lobe
Scallop Loss
ENBW
Coherent Gain
(dB)
(bins)
(dB)
(dB)
Rectangular
-13
3.92
1.0
0.0
von Hann
-32
1.42
1.5
-6.02
Hamming
-43
1.78
1.37
-5.35
Flat Top
-44
0.01
2.96
-11.05
Blackman-Harris
-67
1.13
1.71
-7.53
Improving Dynamic Range
Enhanced resolution uses a low-pass filtering technique that can potentially provide for three
additional bits (18 dB) if the signal noise is uniformly distributed (white). Low-pass filtering should
be considered when high frequency components are irrelevant. A distinct advantage of this
technique is that it works for both repetitive and transient signals. The SNR increase is conditioned
by the cut-off frequency of the ERES low-pass filter and the noise shape (frequency distribution).
LeCroy digital oscilloscopes employ FIR digital filters so that a constant phase shift is maintained.
The phase information is therefore not distorted by the filtering action.
Record Length
Because of its versatility, FFT analysis has become a popular analysis tool. However, some care
must be taken with it. In most instances, incorrect positioning of the signal within the display grid will
significantly alter the spectrum. Effects such as leakage and aliasing that distort the spectrum must
be understood if meaningful conclusions are to be arrived at when using FFT.
An effective way to reduce these effects is to maximize the acquisition record length. Record length
directly conditions the effective sampling rate of the scope and therefore determines the frequency
resolution and span at which spectral analysis can be carried out.
FFT Algorithms
A summary of the algorithms used in the oscilloscope's FFT computation is given here in a few
steps:
1. The data are multiplied by the selected window function.
2. FFT is computed, using a fast implementation of the DFT (Discrete Fourier Transform):
where: xk is a complex array whose real part is the modified source time domain waveform,
WM-OM-E Rev I
233
and whose imaginary part is 0; Xn is the resulting complex frequency-domain waveform;
; and N is the number of points in xk and Xn.
The generalized FFT algorithm, as implemented here, works on N, which need not be a
power of 2.
3. The resulting complex vector Xn is divided by the coherent gain of the window function, in
order to compensate for the loss of the signal energy due to windowing. This compensation
provides accurate amplitude values for isolated spectrum peaks.
4. The real part of Xn is symmetric around the Nyquist frequency, that is
Rn = RN-n
while the imaginary part is asymmetric, that is
In = -IN-n
The energy of the signal at a frequency n is distributed equally between the first and the
second halves of the spectrum; the energy at frequency 0 is completely contained in the
0 term.
The first half of the spectrum (Re, Im), from 0 to the Nyquist frequency is kept for further
processing and doubled in amplitude:
R'n = 2 x Rn_0 n < N/2
I'n = 2 x In__0 n < N/2
5. The resultant waveform is computed for the spectrum type selected.
If "Magnitude" is selected, the magnitude of the complex vector is computed as:
Steps 1-5 lead to the following result:
An AC sine wave of amplitude 1.0 V with an integral number of periods Np in the time window,
transformed with the rectangular window, results in a fundamental peak of 1.0 V magnitude in the
spectrum at frequency Np x Delta f. However, a DC component of 1.0 V, transformed with the
rectangular window, results in a peak of 2.0 V magnitude at 0 Hz.
The waveforms for the other available spectrum types are computed as follows:
Phase: angle = arctan (In/Rn)_Mn > Mmin
_angle = 0_
Mn Mmin
Where Mmin is the minimum magnitude, fixed at about 0.001 of the full scale at any gain setting,
below which the angle is not well defined.
234
WM-OM-E Rev I
X-Stream Operator’s Manual
The dBm Power Spectrum:
where Mref = 0.316 V (that is, 0 dBm is defined as a sine wave of 0.316 V peak or 0.224 V rms,
giving 1.0 mW into 50 ohms).
The dBm Power Spectrum is the same as dBm Magnitude, as suggested in the above formula.
dBm Power Density:
where ENBW is the equivalent noise bandwidth of the filter corresponding to the selected window,
and Delta f is the current frequency resolution (bin width).
6. The FFT Power Average takes the complex frequency-domain data R'n and I'n for each
spectrum generated in Step 5, and computes the square of the magnitude:
Mn2 = R'n2 + I'n2,
then sums Mn2 and counts the accumulated spectra. The total is normalized by the number
of spectra and converted to the selected result type using the same formulas as are used
for the Fourier Transform.
Glossary
This section defines the terms frequently used in FFT spectrum analysis and relates them to the
oscilloscope.
Aliasing If the input signal to a sampling acquisition system contains components whose
frequency is greater than the Nyquist frequency (half the sampling frequency), there will be less
than two samples per signal period. The result is that the contribution of these components to the
sampled waveform is indistinguishable from that of components below the Nyquist frequency. This
is aliasing.
The timebase and transform size should be selected so that the resulting Nyquist frequency is
higher than the highest significant component in the time-domain record.
WM-OM-E Rev I
235
Coherent Gain The normalized coherent gain of a filter corresponding to each window function is
1.0 (0 dB) for a rectangular window and less than 1.0 for other windows. It defines the loss of signal
energy due to the multiplication by the window function. This loss is compensated for in the
oscilloscope. The following table lists the values for the implemented windows.
Window Type
Window Frequency Domain Parameters
Highest Side
Scallop Loss
ENBW
Lobe
(dB)
(bins)
(dB)
Coherent Gain
(dB)
Rectangular
-13
3.92
1.0
0.0
Hanning (Von
Hann)
-32
1.42
1.5
- 6.02
Hamming
-43
1.78
1.37
-5.35
Flattop
-44
0.01
2.96
-11.05
Blackman-Har
ris
-67
1.13
1.71
-7.53
ENBW Equivalent Noise BandWidth (ENBW) is the bandwidth of a rectangular filter (same gain at
the center frequency), equivalent to a filter associated with each frequency bin, which would collect
the same power from a white noise signal. In the table on the previous page, the ENBW is listed for
each window function implemented, given in bins.
Filters Computing an N-point FFT is equivalent to passing the time-domain input signal through
N/2 filters and plotting their outputs against the frequency. The spacing of filters is Delta f = 1/T,
while the bandwidth depends on the window function used (see Frequency Bins).
Frequency Bins The FFT algorithm takes a discrete source waveform, defined over N points, and
computes N complex Fourier coefficients, which are interpreted as harmonic components of the
input signal.
For a real source waveform (imaginary part equals 0), there are only N/2 independent harmonic
components.
An FFT corresponds to analyzing the input signal with a bank of N/2 filters, all having the same
shape and width, and centered at N/2 discrete frequencies. Each filter collects the signal energy
that falls into the immediate neighborhood of its center frequency. Thus it can be said that there are
N/2 "frequency bins."
The distance in hertz between the center frequencies of two neighboring bins is always:
Delta f = 1/T
where T is the duration of the time-domain record in seconds.
The width of the main lobe of the filter centered at each bin depends on the window function used.
The rectangular window has a nominal width at 1.0 bin. Other windows have wider main lobes (see
table).
236
WM-OM-E Rev I
X-Stream Operator’s Manual
Frequency Range The range of frequencies computed and displayed is 0 Hz (displayed at the
left-hand edge of the screen) to the Nyquist frequency (at the rightmost edge of the trace).
Frequency Resolution In a simple sense, the frequency resolution is equal to the bin width Delta
f. That is, if the input signal changes its frequency by Delta f, the corresponding spectrum peak will
be displaced by Df. For smaller changes of frequency, only the shape of the peak will change.
However, the effective frequency resolution (that is, the ability to resolve two signals whose
frequencies are almost the same) is further limited by the use of window functions. The ENBW
value of all windows other than the rectangular is greater than Delta f and the bin width. The table of
Window Frequency-Domain Parameters lists the ENBW values for the implemented windows.
Leakage In the power spectrum of a sine wave with an integral number of periods in the
(rectangular) time window (that is, the source frequency equals one of the bin frequencies), the
spectrum contains a sharp component whose value accurately reflects the source waveform's
amplitude. For intermediate input frequencies this spectral component has a lower and broader
peak.
The broadening of the base of the peak, stretching out into many neighboring bins, is termed
leakage. It is due to the relatively high side lobes of the filter associated with each frequency bin.
The filter side lobes and the resulting leakage are reduced when one of the available window
functions is applied. The best reduction is provided by the Blackman-Harris and Flattop windows.
However, this reduction is offset by a broadening of the main lobe of the filter.
Number of Points The FFT is computed over the number of points (Transform Size) whose upper
bounds are the source number of points, and by the maximum number of points selected in the
menu. The FFT generates spectra of N/2 output points.
Nyquist Frequency The Nyquist frequency is equal to one half of the effective sampling frequency
(after the decimation): Delta f x N/2.
Picket Fence Effect If a sine wave has a whole number of periods in the time domain record, the
power spectrum obtained with a rectangular window will have a sharp peak, corresponding exactly
to the frequency and amplitude of the sine wave. Otherwise the spectrum peak with a rectangular
window will be lower and broader.
The highest point in the power spectrum can be 3.92 dB lower (1.57 times) when the source
frequency is halfway between two discrete bin frequencies. This variation of the spectrum
magnitude is called the picket fence effect (the loss is called the scallop loss).
All window functions compensate for this loss to some extent, but the best compensation is
obtained with the Flattop window.
Power Spectrum The power spectrum (V2) is the square of the magnitude spectrum.
The power spectrum is displayed on the dBm scale, with 0 dBm corresponding to:
Vref2 = (0.316 Vpeak)2,
where Vref is the peak value of the sinusoidal voltage, which is equivalent to 1 mW into 50 ohms.
Power Density Spectrum The power density spectrum (V2/Hz) is the power spectrum divided by
the equivalent noise bandwidth of the filter, in hertz. The power density spectrum is displayed on
WM-OM-E Rev I
237
the dBm scale, with 0 dBm corresponding to (Vref2/Hz).
Sampling Frequency The time-domain records are acquired at sampling frequencies dependent
on the selected time base. Before the FFT computation, the time-domain record may be decimated.
If the selected maximum number of points is lower than the source number of points, the effective
sampling frequency is reduced. The effective sampling frequency equals twice the Nyquist
frequency.
Scallop Loss This is loss associated with the picket fence effect.
Window Functions All available window functions belong to the sum of cosines family with one to
three non-zero cosine terms:
where: M = 3 is the maximum number of terms, am are the coefficients of the terms, N is the number
of points of the decimated source waveform, and k is the time index.
The table of Coefficients of Window Functions lists the coefficients am. The window functions seen
in the time domain are symmetric around the point k = N/2.
Window Type
Coefficients of Window Functions
a0
a1
a2
Rectangular
1.0
0.0
0.0
Hanning (Von
Hann)
0.5
-0.5
0.0
Hamming
0.54
-0.46
0.0
Flattop
0.281
-0.521
0.198
Blackman-Har
ris
0.423
-0.497
0.079
FFT Setup
To Set Up an FFT
1. In the menu bar touch Math, then Math Setup... in the drop-down menu.
2. Touch a Math function trace button: F1 through Fx The number of math traces available
depends on the software options loaded on your scope. See Specifications.; a pop-up
menu appears. Select FFT
from the menu.
3. Touch the Single
or Dual (function of a function)
button if the FFT is to be
of the result of another math operation.
4. Touch inside the Source1 field and select a channel, memory, or math trace on which to
perform the FFT.
238
WM-OM-E Rev I
X-Stream Operator’s Manual
5. Touch inside the Operator1 field: Select FFT from the pop-up menu if you selected Single
function. Select another math function if you selected Dual function. Then touch inside the
Operator2 field and select FFT from the pop-up menu.
6. In the right-hand dialog, touch the FFT tab.
7. Choose whether to Truncate1
or Zero-fill2
the trace display.
8. Touch the Suppress DC checkbox if you want to make the DC bin go to zero. Otherwise,
leave it unchecked.
9. Touch inside the Output type field, and make a selection from the pop-up menu.
10. Touch inside the Window field, select a window type.
11. Touch inside the Algorithm field and select either Least Prime3 or Power of 24 from the
pop-up menu.
1
When the FFT transform size does not match the record length, you can truncate the record and perform an FFT on the
shorter record. This will increase the resolution bandwidth.
2
Zero-fill is useful when the source data for the FFT comes from a math operation that shortens the record. This is
commonly encountered in filtering operations like enhanced resolution. The missing data points are replaced by data values,
whose amplitudes are interpolated to fit between the last data point and th first data point in the record. This guarantees that
there is not a first-order discontinuity in the filled data. Since the data at the end of the record is "filled" data, it is advisable to
select a weighting window other than rectangular to minimize the effect of the fill on the resulting spectrum.
3
The default algorithm is a least primes algorithm that computes FFTs on transform sizes having lengths that can be
N
K
expressed as factors of 2 *5 . This is very compatible with the record lengths encountered in the oscilloscope, which are
often multiples of 1, 2, 4, 5, or 10.
4
N
The other choice is a power of two algorithm where the record lengths are in the form of 2 . The power of 2 algorithm
generally runs faster than the least primes algorithm. The price that is paid is a record length that is not the same as the
N
acquired signal. The power-of-two FFT uses the first 2 points of the record. For example, if you acquire 500 points in your
trace, the power-of-two FFT would only use the first 256 points.
WM-OM-E Rev I
239
ANALYSIS
Pass/Fail Testing
Comparing Parameters
Each Pass/Fail input (Qx) can compare a different parameter result to a user-defined limit (or
statistical range) under a different condition.
The conditions are represented by these comparison operators:
At the touch of a button, test results can also be compared to these standard statistical limits:
•
current mean
•
mean + 1 SD
•
mean + 3 SD
In Dual Parameter Compare mode, your X-Stream scope gives you the option to compare to each
other parameter results measured on two different waveforms. You can set your test to be true if
Any waveform or All waveforms fit the criterion stipulated by the comparison condition. Your setup
is conveniently shown in the Summary box of the Qx dialog. For example:
Mask Tests
You have the choice to do mask testing by using an existing mask, or by using a mask created from
your actual waveform, with vertical and horizontal tolerances that you define. Existing masks can
240
WM-OM-E Rev I
X-Stream Operator’s Manual
be loaded from a floppy disk or from a network.
You can set your mask test to be True for waveforms All In, All Out, Any In, or Any Out. For example,
if you select All In, the test will be False if even a single waveform falls outside the mask.
Masks that you create from your waveform can be confined to just a portion of the trace by use of a
measure gate. (See Measure Gate for an explanation of how this feature works.)
Actions
in the
By touching the Stop Test checkbox
"Actions" dialog, you can set up the test to end after a predetermined number of sweeps that you
decide.
You can also decide the actions to occur upon your waveforms' passing or failing, by selecting one
or all of the following:
•
stop
•
audible alarm
•
print image of display
•
emit pulse
•
save waveform
causes a pulse to be output through the Aux Out connector at
The selection Pulse
the front of the scope. This pulse can be used to trigger another scope. You can set the amplitude
and width of the pulse as described in Auxiliary Output Signals.
Depending on your scope model, you can configure up to 8 pass/fail conditions. The Boolean
conditions to determine if your waveform passes are as follows:
All True
All False
Any True
Any False
All Q1 to Q4 Or All Q5 to Q8
Any Q1 to Q4 And Any Q5 to Q8
Setting Up Pass/Fail Testing
Initial Setup
1.
Touch Analysis in the menu bar, then Pass/Fail Setup... in the drop-down menu.
2.
Touch the Actions tab.
3.
Touch the Enable Actions checkbox. This will cause the actions that you will select to
occur upon your waveform's passing or failing a test.
WM-OM-E Rev I
241
4.
Touch the Summary View to enable a line of text
that
shows concisely the status of your last waveform and keeps a running count of how many
sweeps have passed.
5.
Touch inside the Pass If field, and select a Boolean condition from the pop-up menu.
6.
If you want to set up the test to end after a finite number of sweeps, touch the Stop Test
checkbox. Then touch inside the After data entry field and enter a value, using the pop-up
numeric keypad.
7.
Under "If", touch either the Pass
or Fail
upon your waveform's passing or failing the test.
8.
Under "Then", touch the actions you want to occur: stop test, sound alarm, print result, emit
pulse, or save the waveform. If you want to have the results printed and your scope is not
equipped with a printer, be sure that the it is connected to a local or network printer. See
Printing.
9.
If you want to save your waveform automatically, touch the Save Setup. This will take you
out of the current dialog and will open the "Save Waveform" dialog. See Saving and
Recalling Waveforms.
10.
Test your Pass/Fail conditions by touching the Force Actions Once button. Press the
Clear All button to quickly uncheck all checkboxes if you want to change your selections.
button to set the actions to occur
Comparing a Single Parameter
1. Touch Analysis in the menu bar, then Pass/Fail Setup... in the drop-down menu.
2. Touch a Qx tab; a setup dialog for that position will open.
3. Touch inside the Source1 field and select a source from the pop-up menu.
4. Touch inside the Condition field in the main dialog and select ParamCompare
.
5. Touch inside the Compare Values field and select All or Any from the pop-up menu
. By selecting All, the test will be true only if every waveform falls within the limit
that you will set. By selecting Any, the test will be true if just one waveform falls within the
limit.
242
WM-OM-E Rev I
X-Stream Operator’s Manual
6. Touch inside the Condition field in the "ParamCompare" mini-dialog and select a math
operator from the pop-up menu:
.
7. Touch inside the Limit field and enter a value, using the pop-up numeric keypad. This
value takes the dimensions of the parameter that you are testing. For example, if you are
testing a time parameter, the unit is seconds. If you chose either WithinDeltaPct
or
WithinDeltaAbs
from the Condition menu, you also have the choice of setting the
limit by means of the statistical buttons at the bottom of the "ParamCompare" dialog:
Comparing Dual Parameters
1. Touch Analysis in the menu bar, then Pass/Fail Setup... in the drop-down menu.
2. Touch a Qx tab; a setup dialog for that position will open.
3. Touch inside the Condition field in the main dialog and select DualParamCompare
4. Touch inside the Source1 and Source2 fields and select a source from the pop-up menu.
5. Touch inside the "ParamCompare" mini-dialog field and select a source from the pop-up
menu.
6. Touch inside the Compare Values field and select All or Any from the pop-up menu
WM-OM-E Rev I
243
. By selecting All, the test will be true only if every waveform falls within the limit
that you will set. By selecting Any, the test will be true if just one waveform falls within the
limit.
7. Touch inside the Condition field in the "ParamCompare" mini-dialog and select a math
operator from the pop-up menu:
.
8. Touch inside the Limit field and enter a value, using the pop-up numeric keypad. This
value takes the dimension of the parameter that you are testing. For example, if you are
testing a time parameter, the unit is seconds.
9. If you chose either WithinDeltaPct
or WithinDeltaAbs
menu, touch inside the Delta field and enter a value.
from the Condition
Mask Testing
1. Touch Analysis in the menu bar, then Pass/Fail Setup... in the drop-down menu.
2. Touch a Qx tab; a setup dialog for that position will open.
3. Touch inside the Source1 field and select a source from the pop-up menu.
4. Touch inside the Condition field in the main dialog and select Mask Test
.
5. From the "Test" mini-dialog, make a selection in the Test is True when group of buttons.
244
WM-OM-E Rev I
X-Stream Operator’s Manual
This selection means, for example, that if you select All In the test will be False if even a
single waveform falls outside the mask.
6. From Show Markers, choose whether or not to have mask violations displayed.
7. If you are loading a pre-existing mask, touch the Load Mask tab, then the File button. You
can then enter the file name or browse to its location.
8. If you want to make a mask from your waveform, touch the Make Mask tab.
9. Touch inside the Ver Delta and Hor Delta fields and enter boundary values, using the
pop-up numeric keypad.
10. Touch the Browse button to create a file name and location for the mask if you want to
save it.
11. Touch the Gate tab, then enter values in the Start and Stop fields to constrain the mask to
a portion of the waveform. Or, you can simply touch and drag the Gate posts, which initially
are placed at the extreme left and right ends of the grid.
WM-OM-E Rev I
245
UTILITIES
Status
The status read-only dialog displays system information including serial number, firmware version,
and installed software and hardware options.
To Access Status Dialog
1.
In the menu bar, touch Utilities.
2.
Touch the Status tab.
Remote communication
The Remote dialog is where you can select a network communication protocol, establish network
connections, and configure the Remote Control Assistant log. The choice of communication
protocols is limited to TCPIP and GPIB.
Note: GPIB is an option and requires a GPIB card to be installed in a card slot at the rear of the scope.
Note: The instrument uses Dynamic Host Configuration Protocol (DHCP) as its addressing protocol. Therefore, it is not
necessary to set up an IP address if your network supports DHCP. If it does not, you can assign a static address in the
standard Windows 2000 network setup menu.
The Remote Control Assistant monitors communication between your PC and scope when you are
operating the instrument remotely. You can log all events, or errors only. This log can be invaluable
when you are creating and debugging remote control applications.
To Set Up Remote Communication.
If you are connecting the scope to a network, first contact your Information Systems administrator.
If you are connecting the scope directly to your PC, connect a GPIB or Ethernet cable between
them.
1. In the menu bar touch Utilities, then Utilities Setup... in the drop-down menu.
2. Touch the Remote tab.
3. Make a Port selection: TCPIP (transmission control protocol/Internet protocol) or GPIB
(general purpose interface bus). If you do not have a GPIB card installed, the GPIB
selection will not be accessible.
4. If you are using GPIB, set a GPIB address by touching inside the GPIB Address data entry
field and enter an address.
5. Press the Net Connections button; the Windows Network and Dial-up Connections
window appears.
6. Touch Make New Connection and use the Windows Network Connection Wizard to make
a new connection; or, touch Local Area Connection to reconfigure the scope's connection if
it is already connected to the network.
To Configure the Remote Control Assistant Event Log
1. In the menu bar touch Utilities, then Utilities Setup... in the drop-down menu.
2. Touch the Remote tab.
246
WM-OM-E Rev I
X-Stream Operator’s Manual
3. Touch inside the Log Mode data entry field.
4. Select Off, Errors Only, or Full Dialog from the pop-up menu.
5. To export the contents of the event log to an ASCII text file, touch the Show Remote
Control Log button: the "Event Logs" popup window appears. Touch inside the
DestFilename data entry field and enter a file name, using the pop-up keyboard. Then
touch the Export to Text File button.
Hardcopy
Printing
For print setup, refer to Printing.
Clipboard
This selection prints to the clipboard so you can paste a file into another application (like MS Word,
for example).
To Print from the Clipboard
1. In the menu bar touch Utilities, then Utilities Setup... in the drop-down menu.
2. Touch the Hardcopy tab.
3. Under Colors, touch the Use Print Colors checkbox if you want the traces printed on a
white background. A white background saves printer toner.
4. Touch the Grid Area Only checkbox if you do not need to print the dialog area and you
only want to show the waveforms and grids.
5. Touch the Print Now button.
File
Choose File if you want to output the screen image to storage media such as floppy drive or hard
drive. When outputting to floppy disk, be sure to use a preformatted disk.
To Print to File
1. In the menu bar touch Utilities, then Utilities Setup... in the drop-down menu.
2. Touch the Hardcopy tab, then the File icon.
3. Touch inside the File Format data entry field and select a graphic file format from the
pop-up menu.
4. Under Colors, touch the Use Print Colors checkbox if you want the traces printed on a
white background. A white background saves printer toner.
5. Touch inside the Directory data entry field and type the path to the folder you want to print
to, using the pop-up keyboard. Or touch the Browse button and navigate to the folder.
6. Touch inside the File Name data entry field and enter a name for the display image, using
the pop-up keyboard.
7. Touch the Grid Area Only checkbox if you do not need to print the dialog area and you
WM-OM-E Rev I
247
only want to show the waveforms and grids.
8. Touch the Print Now button.
E-Mail
The instrument also gives you the option to e-mail your screen images, using either the MAPI or
SMTP protocols. Before you output to e-mail from the Utilities dialog, you first have to set up the
e-mail server and recipient address in Preference Setup.
To Send E-mail
1. In the menu bar touch Utilities, then Utilities Setup... in the drop-down menu.
2. Touch the Hardcopy tab, then the E-mail button.
3. Touch inside the File Format data entry field and select a graphic file format from the
pop-up menu.
4. Under Colors, touch the Use Print Colors checkbox if you want the traces printed on a
white background. A white background saves printer toner.
5. Touch the Prompt for message to send with mail checkbox if you want to include
remarks with the image.
6. Touch the Grid Area Only checkbox if you do not need to print the dialog area and you
only want to show the waveforms and grids.
7. Touch the Print Now button.
Aux Output
Refer to Auxiliary Output Signals.
Date & Time
The instrument gives you the choice of manually setting the time and date or getting it from the
Internet. If you elect to get the time and date from the Internet, you need to have the scope
connected to the Internet through the LAN connector on the rear panel. You can also set time
zones and daylight savings time.
To Set Time and Date Manually
1. In the menu bar touch Utilities, then Utilities Setup... in the drop-down menu.
2. Touch the Date/Time tab.
3. Touch inside each of the Hour, Minute, Second, Day, Month, and Year data entry fields
and enter a value, using the pop-up numeric keypad.
4. Touch the Validate Changes button.
To Set Time and Date from the Internet
The Simple Network Time Protocol (SNTP) is used.
1. Ensure that the scope is connected to the Internet through the LAN connector at the rear of
248
WM-OM-E Rev I
X-Stream Operator’s Manual
the scope.
2. In the menu bar touch Utilities, then Utilities Setup... in the drop-down menu.
3. Touch the Date/Time tab.
4. Touch the Set from Internet button.
To Set Time and Date from Windows
1. In the menu bar touch Utilities, then Utilities Setup... in the drop-down menu.
2. Touch the Date/Time tab.
3. Touch the Windows Date/Time button
.
4. Use the Time & Date Properties window to configure the time, including time zone:
WM-OM-E Rev I
249
Options
Use this dialog to add or remove software options. For information about software options, contact
your local LeCroy Sales and Service office, or visit our Web site at http://www.lecroy.com/options.
Options that you purchase, such as JTA2, add performance to you instrument. This added
performance is seen in the new math functions or parameters that you can choose from when doing
Measure or Math setups.
Preferences
Audible Feedback
You can elect to have audible confirmation each time you touch a screen or front panel control.
1. In the menu bar touch Utilities; then touch Preferences in the drop-down menu.
2. Touch the "Audible Feedback" Enable checkbox so that the scope emits a beep with each
touch of the screen or front panel control.
Auto-calibration
You can choose to have your instrument automatically recalibrate itself whenever there is a
significant change in ambient temperature. If you do not enable this option, the scope will only
recalibrate at startup and whenever you make a change to certain operating conditions.
1. In the menu bar touch Utilities; then touch Preferences in the drop-down menu.
2. Touch the "Automatic Calibration" Enable checkbox.
Offset Control
As you change the gain, this control allows you to either keep the vertical offset level indicator
stationary (when Div is selected) or to have it move with the actual voltage level (when Volts is
selected). The advantage of selecting Div is that the waveform will remain on the grid as you
increase the gain; whereas, if Volts is selected, the waveform could move off the grid.
Note: Regardless of whether you select Volts or Div, the "Offset" shown in the channel setup dialog always indicates volts.
However, when Div is selected for the Offset Control, the offset in volts is scaled proportional to the change in gain, thereby
keeping the division on the grid constant.
1. In the menu bar touch Utilities; then touch Preferences in the drop-down menu.
2. Touch the Acquisition tab.
3. Under Offset Setting constant in:, touch either the Div or Volts button.
Delay Control
As you change the timebase, this control allows you to either keep the horizontal offset indicator
stationary (when Div is selected) or to have it move with the trigger point (when Time is selected).
The advantage of selecting Div is that the trigger point will remain on the grid as you increase the
timebase; whereas, if Time is selected, the trigger point could move off the grid.
Note: Regardless of whether you select Time or Div, the "Delay" shown in the timebase setup dialog always indicates time.
However, when Div is selected for Delay In, the delay in time is scaled proportional to the change in timebase, thereby
keeping the division on the grid constant.
250
WM-OM-E Rev I
X-Stream Operator’s Manual
1. In the menu bar touch Utilities; then touch Preferences in the drop-down menu.
2. Touch the Acquisition tab.
3. Under Delay Setting constant in:, touch either the Div or Volts button.
Trigger Counter
Checking the Reset trigger counter before starting a new acquisition checkbox clears the
trigger counter each time the scope issues an arm acquisition command. This applies when you
have set a trigger Holdoff condition in the Trigger dialog in either time or events:
The default condition of this control is off (unchecked).
Performance Optimization
You can set up the scope to optimize either calculating speed or display speed. If the display
update rate is of primary concern to you, optimize for Display. If acquisition and analysis are more
important, optimize for analysis. Optimizing for analysis can be useful when persistence or
averaging is used, giving higher priority to waveform acquisition at the expense of display update
rate.
The choices are presented as a spectrum with highest values at the extremes:
1. In the menu bar touch Utilities; then touch Preferences in the drop-down menu.
2. Touch one of the optimization icons.
E-mail
Before you can send e-mail from the scope, it must first be configured.
1. In the menu bar touch Utilities, then Preference Setup... in the drop-down menu.
2. Touch the E-mail tab.
3. Choose an e-mail server protocol: MAPI (Messaging Application Programming Interface)
is the Microsoft interface specification that allows different messaging and workgroup
applications (including e-mail, voice mail, and fax) to work through a single client, such as
the Exchange client included with Windows 95 and Windows NT. MAPI uses the default
Windows e-mail application (usually Outlook Express). SMTP (Simple Mail Transfer
Protocol) is a TCP/IP protocol for sending messages from one computer to another
through a network. This protocol is used on the Internet to route e-mail. In many cases no
WM-OM-E Rev I
251
account is needed.
4. If you chose MAPI, touch inside the Originator Address (From:) data entry field and use
the pop-up keyboard to type in the instrument's e-mail address. Then touch inside the
Default Recipient Address (To:) data entry field and use the pop-up keyboard to enter
the recipient's e-mail address.
5. If you chose SMTP, touch inside the SMTP Server data entry field and use the pop-up
keyboard to enter the name of your server. Touch inside the Originator Address (From:)
data entry field and use the pop-up keyboard to type in the instrument's e-mail address.
Then touch inside the Default Recipient Address (To:) data entry field and use the
pop-up keyboard to enter the recipient's e-mail address.
6. You can send a test e-mail text message by touching the Send Test Mail button. The test
message reads "Test mail from [name of scope's email address]."
Acquisition Status
For each general category of scope operation, you can view a summary of your setups. These
dialogs are not accessible through the Utilities menu, but are instead accessed from the menu bar
drop-down menus. The categories are as follows:
•
Vertical -- select Channels Status . . . from drop-down menu
•
Timebase -- select Acquisition Status . . . from drop-down menu
•
Trigger -- select Acquisition Status . . . from drop-down menu
•
Math -- select Math Status . . . from drop-down menu
In addition to these dialogs, summaries are also provided for XY setups, memory (M1-M4) setups,
and time stamps for sequence mode sampling.
Service
This button provides access to service dialogs, which are for the sole use of LeCroy
service personnel. A security code is required to gain access.
Show Windows Desktop
Touching the Show Windows Desktop button
in the main "Utilities" dialog minimizes the
instrument application to reveal the underlying desktop. To maximize the application, touch the
appropriate shortcut icon:
252
WM-OM-E Rev I
X-Stream Operator’s Manual
.
Touch Screen Calibration
Touching the Touch-Screen Calibration button
starts the calibration procedure. During
the procedure, you will be prompted to touch the center of a small cross in 5 key locations on the
touch screen. Because sufficient accuracy cannot be achieved using your finger, use a stylus
instead for this procedure. The calibration has a ten-second timeout in case no cross is touched.
To avoid parallax errors, be sure to place your line of sight directly in front of each cross before
touching it.
WM-OM-E Rev I
253
CUSTOMIZATION
Customizing Your Instrument
The instrument provides powerful capability to add your own parameters, functions, display
algorithms, or other routines to the scope user interface without having to leave the instrument
application environment. You can customize the instrument to your needs by using the power of
programs such as Excel™, Mathcad™, and MATLAB™, or by scripting in VBS. Whichever method
you use, the results appear on the instrument's display together with the signals that you started
with. This ability offers tremendous advantages in solving unique problems for a large range of
applications, with comparatively little effort from you.
Introduction
Instrument customization provides these important capabilities:
•
You can export data to programs, without leaving the instrument environment.
•
You can get results back from those programs, and display them on the instrument,
without leaving the instrument application environment.
•
Once the result is returned, you can perform additional scope operations, such as
measuring with cursors, applying parameters, or performing additional functions on the
waveform, in exactly the same way as for a normal waveform.
•
You can program the scope yourself.
The instrument does not just provide connectivity with data downloads to other programs. It
provides true customizable interaction with these other programs, and allows you to truly customize
the scope to do the exact job you want it to do. The advantages to this are many:
•
You can use the standard processing power of the instrument to do most of your
calculations
•
You only need to write the function, parameter, display algorithm, etc. that specifically
applies to your need and that the instrument doesn’t contain.
•
You can view the final result on the instrument display, and use all of the instrument's
tools to understand the result.
•
You can do additional processing on the result by applying either standard instrument
parameters, functions, etc. to the returned result, or even more powerfully, adding
chained customized functions. For example, you can do an Excel calculation on a
result with a MATLAB function applied to it.
Solutions
Engineers do not buy equipment; they buy solutions. But what solutions can be reached from a set
of instrument waveform data? In principle, anything that can be logically derived from those data,
given the limitations of signal-to-noise ratio and processing time. Here are some examples of what
can be done with a customized instrument:
•
254
Changing the units of a grid to joules, newtons, amps, etc.
WM-OM-E Rev I
X-Stream Operator’s Manual
•
Creating a new waveform by manipulating the data of one or two input waveforms
•
Creating a new waveform without using any of the input data
•
Creating a new parameter by manipulating the data of one or two input waveforms
•
Changing a vertical scale or a horizontal scale from linear to non-linear
You don’t have to use all the data from the input waveforms: you can select data from one or more
segments, which need not be aligned in the two-input waveforms.
Examples
Example 1: Simple math functions using VBScript
WaveOut is the waveform being returned to the instrument (F1 in this case). WaveIn is the input
waveform (C1 in this case) You can see that the F1 result is displayed on the scope, and can be
processed further.
Example 2: Another simple math function using VBScript
Example 3 below doesn’t use the input data at all. The middle waveform (F2) is a "golden
waveform", in this case a perfect sine (subject to 16-bit resolution), that was created using a
VBScript. The lower trace (F3) is a subtraction of the acquired waveform (upper trace) and the
WM-OM-E Rev I
255
golden waveform. The subtraction (of course) contains all the noise, but it also shows the presence
of a very small square wave signal.
Example 3
Here is the VBScript that produced the "golden sine" (F2 above):
Frequency = 3000000.0
' Frequency of real data
SampleTime = InResult.HorizontalPerStep
Omega = 2.0 * 3.1416 * Frequency * SampleTime
Amplitude = 0.15
' Amplitude of real data
For K = 0 To LastPoint
newDataArray(K) = Amplitude * Sin(Omega * K)
Next
OutResult.DataArray(True) = newDataArray ' Data in volts
OutResult.DataArray is the waveform returned to the scope and displayed on the scope as the F2
waveform.
256
WM-OM-E Rev I
X-Stream Operator’s Manual
Example 4
Example 4 is a measurement of DVI (Digital Video Interface) Data-Clock skew jitter measurement,
using a VBScript to emulate the PLL.
In this example, a customer was not able to probe the desired clock signal. The only probing point
available was the output differential clock signal (C2). However, that clock was a factor of 10 slower
than the clock embedded in the data signal (C3). By using a VBScript to create a clock waveform of
the appropriate frequency (waveform F1), the customer was able to display and measure
data-clock skew using a LeCroy instrument function and parameter.
WM-OM-E Rev I
257
Example 5
Next, a logarithmic vertical scale, for which the script can be found here. (Most scripts would be far
simpler than this one.)
Frequency response curves are frequently drawn on a logarithmic scale. The upper trace is a
frequency spectrum of a square wave after enhanced resolution has been applied. It was created
using instrument functions. The lower trace is the first lobe of the FFT display. But with a logarithmic
frequency scale. Click here for the VBScript.
In addition to VBScripting, MATLAB, Mathcad, or Excel can also be used to generate a result. The
F1 trace (shown below in Example 6) was calculated in MATLAB (F1=WformOut) from C1
(WformIn1) and C2 (WformIn2). The same calculation could also be done in Excel by using a
simple formula in a spreadsheet cell.
258
WM-OM-E Rev I
X-Stream Operator’s Manual
Example 6
Summary
The examples above illustrate only the capability to use VBScript and MATLAB. The instrument
with the LeCroy XMAP software option allows you to use Excel, Mathcad, MATLAB, and VBScript
in this manner. Of course, you will need to load Excel, Mathcad, or MATLAB in the scope (VBScript
WM-OM-E Rev I
259
does not require any additional software) to take advantage of the capability. You can think of these
functions as "subroutines" of the instrument's main software, which take in waveform data and
other variables like vertical scale and offset, and horizontal scale and offset. These functions then
return a waveform or a parameter as required. In addition, you can view the calculated data directly
in Excel, MATLAB, or Mathcad, if you desire.
What is Excel?
Excel is a program within Microsoft Office. With it you can place data in the cells of a spreadsheet,
calculate other values from them, prepare charts of many kinds, use mathematical and statistical
functions, and communicate with other programs in Office. From the instrument you can send data
to Excel (where processing can take place) and return the results to the instrument.
What is Mathcad?
Mathcad is a software package from MathSoft. It provides an integrated environment for performing
numerical calculations and solving equations, and communicating with other programs. Results
can be presented in tabular or graphical form.
What is MATLAB?
MATLAB is a software package from MathWorks that provides an environment for work in
computation and mathematics. An interactive language and graphics are provided.
What is VBS?
VBS is a programming language, but you don’t write it in a special environment such as C++ or
Visual Basic; you write it within your own application. In the instrument, a few clicks or button
pushes will get you into an editing panel where you can write what you want. You cannot crash the
scope, or in any other way interfere with its workings, because the system is completely protected.
A product of Microsoft and a subset of Visual Basic, VBS can be learned very quickly if you have
some experience in any programming language. The VBS processing function can collect a
number of useful variables from the scope, including waveform data and useful variables such as
volts per division and time per division. The output from a script can be a waveform or a parameter,
and you can choose your own values for variables such as volts per division.
The idea of a VBS function is that you start with an input waveform, operate on some or all of the
values with a script, and show the result on a scope grid, like any other waveform.
VBScript customization is built into the instrument, so no additional programs need to be loaded to
take advantage of this capability.
The following diagrams were made by changing a small part, in some cases just one line, of a
standard VBScript. VBS is a well-known standard language, with excellent support documentation,
and it is easy to use in several different environments.
260
WM-OM-E Rev I
X-Stream Operator’s Manual
WM-OM-E Rev I
261
These examples are purely illustrative, but you can easily imagine that with a VBScript you can add
value to the scope in a very short time. This gives you an instrument that does exactly what you
want, time after time, by using your stored setups and scripts.
What can you do with a customized instrument?
If you require a result that can be derived logically from the input waveform, you can do it. Many
calculations can be done with remarkably small scripts, but if you have no time for scripting, you
can use one of the proprietary packages, such as Excel, MATLAB, or Mathcad, which offer
immense processing power.
Scaling and Display
Scripting and programming allow a large variety of opportunities. You may, for example, be using
transducers. If so, you can change the units of your waveforms, and write N (newtons), J (joules)
and so on, and you can introduce scaling factors. If the transducers are non-linear, you can correct
for that, too. You can also transform horizontal scales and vertical scales by manipulating the data.
Logarithmic scales in amplitude and frequency are often required. Squaring and taking square
roots are needed in certain applications. Here is a picture showing some graphs related to white
noise, showing ways of detecting small deviations from the true distribution. The lower two graphs
were generated and placed in one trace using a VBScript.
In the next example, four graphs are placed in one trace.
Golden Waveforms
This is a rich field for VBS. An example was given earlier. The only limits to the shapes that can be
generated are the vertical resolution and the number of samples.
A practical example - DVI Data-Clock skew
The next example is a measurement of DVI Data-Clock skew jitter measurement, using a VBScript
to emulate the PLL. A solution to a practical measurement problem was shown earlier.
These are just a few of the many solutions that can be created.
262
WM-OM-E Rev I
X-Stream Operator’s Manual
Number of Samples
The various math packages can process samples as follows:
Excel
65,535 samples
Mathcad
5 MS
The number of samples that MATLAB can process is determined by memory option, as
follows:
Memory Length
System DRAM
Buffer Length
STD, S, M
256 MB
40 MB
L, VL
512 MB
200 MB
XL
1 GB
400 MB
XXL
2 GB
400 MB
Calling Excel From Your Instrument
Calling Excel Directly from the Instrument
Excel can be directly called from the instrument in two ways:
Using a function
F1 through Fx The number of
math traces available depends
on the software options loaded Excel returns a waveform
on your scope. See
Specifications.
Using a parameter
P1 through Px The number of
parameters available depends
on the software options loaded Excel returns a parameter
on your scope. See
Specifications.
In both cases, one call to Excel can use two separate waveforms as input.
Notes:
Excel has a calculation algorithm of 64,000 points (32,000 if you have created a chart in Excel). Therefore, make sure that
your acquisition has less than this number of points if you are going to use an Excel calculation.
To use this capability, you must have the LeCroy XMAP software option and Excel loaded in your instrument. Select
Minimize from the instrument's File menu to access the Excel program directly.
How to Select a Math Function Call
The Excel math function is selected from the Math Operator menu, where it appears in the
Custom group.
WM-OM-E Rev I
263
How to Select a Parameter Function Call
The Excel Parameter function is selected from the Select Measurement menu, where it appears in
the Custom group.
The Excel Control Dialog
Once you have invoked an Excel call, you will see a dialog at the right of the screen, allowing you to
control the zoom, Excel properties, linking cells, and scale of the output trace from Excel:
Entering a File Name
If you uncheck the New Sheet checkbox, you can enter the file name of an existing file.
Create Demo Sheet Calls up a default Excel spreadsheet.
Add Chart Adds charts of your waveforms to Excel. You can go into Excel and create as many
charts as you want.
264
WM-OM-E Rev I
X-Stream Operator’s Manual
Organizing Excel sheets
The Cells tab allows you to organize your Excel chart. When placing the components in the sheet,
be careful to avoid over-writing needed information, especially when you are using multiple input
waveforms. As depicted here, the instrument panel has been pasted over the Excel sheet:
There are three arrays of data for the three waveforms: up to two inputs and one output. There are
corresponding small arrays of information about each trace.
Scale Setting the Vertical Scale
The vertical scale of the output waveform from Excel may be set in three ways:
WM-OM-E Rev I
Automatic
For each acquisition, the instrument fits the
waveform into the grid.
Manual
For one acquisition, click Find Scale; the
instrument fits the current waveform into the grid.
265
All subsequent acquisitions will use this scale
until you make a change.
From Sheet
The scale is taken from the specified cells in the
Excel sheet, H2 through H10 in the example
above, where cell H2 was specified as the top of
the data set, as depicted below.
Trace Descriptors
The next figure explains the meanings of the descriptors for each trace.
Multiple Inputs and Outputs
If you invoke two or more instrument parameter functions or waveform functions that call Excel, you
will find that they all refer to the same spreadsheet by default. Thus, your spreadsheet can use the
data from several waveforms, and you can derive many different combinations of output
parameters and waveforms, including some of each, from your spreadsheet. You only have to be
careful about the positioning of your cell ranges within the sheet so that no conflicts occur.
Because filling cells in the spreadsheet is a relatively slow process, all unwanted sources (inputs)
should be left disabled (unchecked). For example, if you want one waveform and two parameters
266
WM-OM-E Rev I
X-Stream Operator’s Manual
derived from the data of three waveforms, you can have one function with both sources enabled,
one with one source enabled, and one with no sources enabled. The alternative is to use one input
in each function.
Simple Excel Example 1
In this example we use Excel to invert or negate a waveform. The first figure shows a part of the
screen. The upper trace is the original signal. The lower is the result from Excel.
The dialog is the one that controls the location of the data in the Excel worksheet.
The input data are in columns A and B (though, only the first is used) and the output is in column C.
All have been set to start at row 2, allowing space for a title in row 1.
WM-OM-E Rev I
267
Columns D, E and F contain the headers for the three waveforms. These are the set of numbers
that provide the description of the scope settings, such as vertical scale and offset, and number of
samples.
In this figure, the panel has been pasted onto the Excel sheet for comparison:
268
WM-OM-E Rev I
X-Stream Operator’s Manual
To get the output values in column C, we set C2 = - A2 and copy this formula down the column. This
is the only action needed in Excel, and can be seen in the next figure:
Simple Excel Example 2
In this example we use Excel to invert or negate a waveform. The first figure shows a part of the
instrument screen. The upper trace (C1) is the original signal. The lower trace (F1) is the result
calculated in Excel and displayed on the screen.
WM-OM-E Rev I
269
The input data is in columns A and B (though by default, only a single input/column is used), and
the output is in column C. All have been set to start at row 2 (which allows for a header in row 1).
To create this waveform, you would simply do the following:
1. Ensure that your acquisition has no more than 64 kpts (the Excel calculation limit)
2. Choose a function, and select ExcelMath as Operator1 for the function. Excel will open
automatically in the background.
270
WM-OM-E Rev I
X-Stream Operator’s Manual
3. Choose File, Minimize from the menu bar to minimize the instrument display and open the
Excel program.
4. Create your formula for each data point in column A (in this case, our formula for cell C2 is
-A2, copied for the entire column), as shown here:
WM-OM-E Rev I
271
.
5. Retrigger the scope (if it is not currently triggering)
6. Return to the program
Note that the only action that was needed in Excel was to create the formula in column C for each
data point in column A. The instrument automatically opens Excel, puts the waveform data in the
correct columns, and returns the calculated data back to the display as the chosen F trace. This
Excel-calculated trace can have further measurements or math calculations performed on it, if
desired.
You can also create a chart of the data in Excel automatically and view the data there. Simply press
the Add Chart button in the instrument's Excel dialog and a chart of the input (top chart) and Excel
calculated output (bottom chart) will be automatically created in the spreadsheet. The chart will be
updated automatically as the scope is triggered.
272
WM-OM-E Rev I
X-Stream Operator’s Manual
Exponential Decay Time Constant Excel Parameter (Excel Example 1)
This example calculates the time constant of an exponentially falling pulse, such as the light output
of a phosphor.
The first figure shows a typical pulse, including pseudo-random noise, generated by a VBScript.
WM-OM-E Rev I
273
The pulse was generated by a formula of the form e(1 - t/TC1) * e-t/TC2, where TC1 and TC2 are time
constants, The requirement is to measure the time constant TC2, using the portion of the trace
where TC1 has negligible effect. This was done using Function F1, which is not a part of the
measurement process.
For the actual measurement, Parameter P1 was set up as an Excel call. In Excel, the selected
portion of the trace was converted to logarithms, and the Excel function SLOPE was used, as
shown here:
274
WM-OM-E Rev I
X-Stream Operator’s Manual
Here we see the input data in column B (with a time scale in A) created using the contents of cell F9,
Horizontal Per Step. The logarithmic data are in column D, with the time scale repeated in C. The
output appears in cell H3, using the formula =1/SLOPE(D21:D51,C21:C51).
WM-OM-E Rev I
275
Gated Parameter Using Excel (Excel Example 2)
This example calculates a parameter of a waveform, in a region of interest defined by the leading
edges of two pulses in a separate waveform.
This figure shows the instrument screen:
The traces were made using VBS scripts in functions F1 and F2, based on pseudo-random
numbers to provide noise and varying pulse widths. Randomize Timer: Randomize Timer was used
in both scripts to ensure that successive acquisitions produced different data. Script F1 generates
pulses with widths that are multiples of a set clock period. F2 generates one pulse in the first half of
the time window, and one pulse in the second half. Both pulses are constrained to coincide with the
clock pulses of F1. F1 and F2 are used here only as simulations and are not part of the
measurement process, which only uses P1.
The call to Excel is made through Parameter P1.
The next figure shows a part of the Excel workbook.
276
WM-OM-E Rev I
X-Stream Operator’s Manual
Here we see the gated waveform that has been created in Excel. The Mean parameter during the
region of interest (ROI) is placed in cell H3.
How Does this Work?
The amplitude of the signal is about 0.3 volts, and the screen height is 0.4 volts, as derived from
cells F7 and Fx. A threshold value for amplitude was calculated by placing 0.5 * (Fy - Fx) in cell A4.
Remember that in the instrument the sources were defined to be A10 and B10. This means that the
first point on the waveform will be read into A10, and, since the waveform has 500 points, the last
point will be read into A510. The same holds true for F2 and column B, since F2 is assigned as
Source2, and data is defined to write into column B starting with cell B10.
To create the gating function in column C, the cell C10 was given the following formula:
IF ( ( B10 - B9) > $A$4, 1 - C9, C9). This was copied down the column. Column D, the output
column, is simply A * C.
The output was defined as cell H3.
The required mean in cell H3 is given by SUM (D10 : D509) / SUM (C10 : C509), for a 500 point
waveform.
Correlation Excel Waveform Function (Excel Example 3)
This example uses an Excel waveform function to examine the cross-correlation between two
signals, which are both noisy sinusoidal segments. The correlation trace is, of necessity, shorter
than the input traces.
WM-OM-E Rev I
277
The noise was generated using pseudo-random numbers. Randomize Timer was included in the
VBScript to ensure that the two traces differed, and that subsequent acquisitions differed.
Functions F1 and F2 are included only to simulate signals, and are not part of the measurement
process, which is performed by F3.
This example used the CORREL (Array1, Array2) function of Excel, as depicted below:
278
WM-OM-E Rev I
X-Stream Operator’s Manual
Multiple Traces on One Grid (Excel Example 4)
This example shows how you can place multiple traces in one picture, with only two operations in
an Excel sheet. Depicted below is an example from an Excel spreadsheet.
WM-OM-E Rev I
279
Here is an original instrument trace:
The method is very simple. First, the waveform is transferred to an Excel spreadsheet by means of
an instrument Excel call. Second, two operations are needed in Excel: placing a simple formula in
one cell, and copying that formula into a range of cells.
Depicted below is the required Excel formula:
280
WM-OM-E Rev I
X-Stream Operator’s Manual
In fact, the simple expression B374 + 0.02 comprises several components. The original instrument
trace is in column B, and the plot is required to start at cell B134. The traces repeat at intervals of
250 cells. Let us call this interval R. If we require a horizontal displacement D, then in cell CN we
write B(N + R - D). In this example D is 10. Finally we may want a vertical displacement V, and we
write B(N + R - D) + V. In this example, V is 0.02. D and V can be zero if required, as depicted below.
All that remains is to copy the formula to the required range of cells.
WM-OM-E Rev I
281
282
WM-OM-E Rev I
X-Stream Operator’s Manual
Using a Surface Plot (Excel Example 5)
WM-OM-E Rev I
283
Writing VB Scripts
VBScripting is one of the custom features of your instrument. Others include the ability to work with
programs such as Excel, Mathcad and MATLAB.
Types of Scripts in VBS
The instrument's VBS provides two types of script.
•
The Waveform Function script allows you to take the data from one or two traces and make
a new trace whose values may depend on the values of the input trace.
•
The Parameter Function script also takes in the data from one or two traces, but it only has
one output. This output is the zeroth element in the output array. It appears as a parameter
value on the instrument's screen. The remainder of the array is currently not used, and is
not accessible.
Within both types of script, you can call Excel.
Loading and Saving VBScripts
From the editing panel you can save your script and you can load a previous one. Should you forget
to save a script, please note that when you save your setup, it has your current scripts embedded in
it. Therefore it is a good idea to save your setup frequently. It is worth saving the script separately
as well, because it is saved in a suitable format for printing or off-line editing with Notepad. Note
that in both these examples the input data are referred to as InResult.DataArray. You can also write
InResult1.DataArray and InResult2.DataArray, which refer to the two input traces.
InResult.DataArray always refers to input trace 1. These remarks hold for any script that you write.
Example Waveform Function Script: Square of a waveform
' Example script to produce a waveform
This example calculates the square of
the input waveform.
OutResult.Samples = InResult.Samples ' Visible trace length + 1
' Note that a trace of nominal length 1000 comprises data numbered from
' 0 to 1001. The 1001st point is not visible, so you
' normally use points 0 to 1000,
' giving 1001 points and 1000 intervals between points.
startData = 0
endData = OutResult.Samples
LastPoint = endData - 1 ' because the last point is invisible.
ReDim newArray(OutResult.Samples) ' to store the results
unscaledData = InResult.DataArray(False)
284
WM-OM-E Rev I
X-Stream Operator’s Manual
' InResult.DataArray(False) provides
' integer data from -32768 to 32767.
' InResult.DataArray(True) provides real data
' in the same physical unit as the vertical scale of the input trace.
ScaleFactor = 1.0 / 32768 ' to make the trace fill the screen.
For i = 0 To LastPoint
newArray(i) = ScaleFactor * (unscaledData(i)) ^ 2
Next
OutResult.DataArray(False) = newArray ' signed long integer data output
Example Parameter Function Script: RMS of a waveform
' Example script to produce a parameter.
' This script calculates the root mean square
' of the input waveform.
' Note that a trace of nominal length 1000 has data from
' 0 to 1001. The 1001st point is not visible, so you
' normally use points 0 to 1000,
' giving 1001 points and 1000 intervals between points.
startData = 0
endData = InResult.Samples
LastPoint = endData - 1 ' because the last point is invisible.
ReDim newArray(InResult.Samples) ' to store the results
unscaledData = InResult.DataArray(True)
' InResult.DataArray(False) provides
' integer data from -32768 to 32767.
' InResult.DataArray(True) provides real data
' in the same unit as the vertical scale of the trace.
Total = 0
For i = 0 To LastPoint
Total = Total + (unscaledData(i)) ^ 2
Next
NewArray(0) = Sqr (Total / (LastPoint + 1)) Place the result in the zeroth
WM-OM-E Rev I
285
element.
OutResult.ValueArray(True) = newArray ' integer data output
The default waveform function script: explanatory notes
InResult.Samples is the number of points in the incoming waveform.
InResult.DataArray(Boolean) (or InResult1.DataArray or InResult2.DataArray) is the array of input
data. If the Boolean is True you get scaled real data in the units of the trace. If the Boolean is false
you get unscaled integer data in the range -32768 to + 32767.
The value of InResult.Samples is the total number of data in a trace. It is two more than the nominal
value given on the screen. The first point DataArray(0), coincides with the left edge of the screen,
apart from the wobble caused by the trigger-to-sample clock difference. If the trace length is
nominally 500, the right edge of the screen coincides with DataArray(500), which is the 501st point.
The last point, number 502, is just off the right of the screen, and is never seen. That is why the loop
in the script runs only to endData - 1.
OutResult.Samples is the number of data in the output trace, and is set to be the same as the
number of data in the input trace. If you set the output length less than the input length, you get a
shorter trace, the remainder being made of zeroes. If you try to set the output values to something
illegal, you may find that a part of the trace retains the values from a previous acquisition.
If you try to set something outside the bounds of an array, or you make some other error, or
something overflows, or you ask for something impossible, such as log(-13), the instrument tells
you the line number, and the nature of the problem. Other types of error may not be given the
correct line number, for example, if "Next" or "End If" is omitted, because VBS does not know where
it should have been.
UnscaledData is simply a copy of the input data set.
ReDim newDataArray(OutResult.Samples) defines an array of data for use as a scratch pad. Dim
is short for Dimension, which is used in Visual Basic to declare a variable (even if it only has one
element, in which case you omit the size of the array).
InResult.DataArray(False) means that the data are signed integers in the range -32768 to 32767.
False is a Boolean value applying to the property Scaled. Scaled data are specified in the units of
the vertical scale, such as volts. You get these by putting "True" instead of "False". If you want to
make a section of the output trace invisible, you simply set the data values to full scale or bigger,
top or bottom.
You can start with the unscaled data (False) as input, and then set the output data to scaled data
(True), and you can go from scaled to unscaled. Using scaled data, an overflow will make a picture
like this:
286
WM-OM-E Rev I
X-Stream Operator’s Manual
You can also start with True and convert to False, but in this case overflows will cause an error
message.
Anything after a single quotation mark on a line will not be used by the instrument. This feature is
intended for comments, for example
' This is a comment.
A = Amp * Sin(Omega * T) Calculate the output.
InResult.DataArray and OutResult.DataArray are only to be used as shown in the default scripts
and in the example scripts: you cannot refer directly to individual elements of these arrays. You
have to use your own arrays, in this example, unscaledData and newDataArray. You are not
allowed to write statements like the following:
Y = InResult.DataArray (17)
OutResult.DataArray (257) = Z
Some parts of the default script must not be changed because they are a part of the interface.
These are highlighted in the following script .
' TODO add your custom code here accessing OutResult and InResult objects
' Here's a small example that just inverts the waveform.
OutResult.Samples = InResult.Samples
startData = 0
endData = OutResult.Samples
newNumPoints = endData - startData
ReDim newDataArray (OutResult.Samples)
unscaledData = InResult.DataArray (False)
WM-OM-E Rev I
287
For i = 0 To endData - 1
newDataArray (i) = - unscaledData (i)
Next
OutResult.DataArray (False) = newDataArray _' only support raw data
The four highlighted quantities are parts of the interface. The names must be retained. Furthermore,
InResult.Samples and InResult.DataArray are inputs, and their values cannot be changed.
OutResult.Samples and OutResult.DataArray are outputs, and can be changed, but not directly
through their individual elements.
The default parameter function script: explanatory notes
The default parameter script is similar to the default waveform script, but there are subtle
differences.
First, the size of the data array is the same as the nominal value: you cannot use or see the extra
two points. So "500 points" means just that: 500 points.
Second, the output looks like an array, but only element zero is currently used. You must copy your
parameter result into newValueArray(0). As with the arrays of the Waveform Script, you cannot
refer directly to elements of the input and output arrays. You may not write something like
OutResult.ValueArray (0) = P.
Note that the unit of the parameter is displayed as the same as the vertical unit of the trace, even if
you have squared the data, for example, unless you change the unit yourself.
The default parameter script is shown below.
' TODO add your custom code here accessing OutResult and InResult objects
' Here's a small example that just inverts the waveform
numParam = InResult.Samples
ReDim newValueArray(numParam)
scaledData = InResult.DataArray
For i = 0 To numParam-1
newValueArray(i) = -scaledData(i)_' Change this to do something useful.
Next
OutResult.ValueArray = newValueArray 'only support raw data
Your parameter script should include something like this:
A. Do calculation to obtain your parameter value from the input data array.
B. newValueDataArray (0) = ParameterValue
C. OutResult.ValueArray = newValueArray
You can test this script using setup MeanDemoScriptApr2.lss.
288
WM-OM-E Rev I
X-Stream Operator’s Manual
You can edit scripts using Notepad, but you will not get any notification of errors.
You are not allowed to write OutResult.ValueArray(0) = MeanParameter.
InResult.DataArray and OutResult.DataArray are only to be used as shown in the default scripts
and in the example scripts. You cannot refer to, or modify, any individual element in these arrays.
Scripting with VBScript
Separators
The two separators in VBS are the colon : and the single quotation mark .
Using the colon, you can place two or more statements on a line, for example:
XMin = 0.0 : XMax = 800.0 : YMin = 0.0 : YMax = 600.0
There is also an implied separator whenever a new line is begun.
Using the quotation mark you can signify that the remainder of the line is a comment:
non-executable material that is usually used to clarify the workings of the script. For example:
RMSMax = 32767 / Sqr (2)
be
' RMS of the largest sinusoid that can
' fitted into the screen in unscaled mode.
To continue a comment on to another line, another quotation mark is required on the new line.
Variable Types
VBS supports the following variable types:
Integer
signed 16 bit value in the range -32768 to 32767
Long
signed 32 bit value in the range -231 to +231 - 1
Single
real number or floating point number
Double
real number or floating point number
Boolean
Boolean or logical value
String
string of characters
When making comparisons using real numbers, beware of testing for equality, because of rounding
errors. It may be better to apply a tolerance band. For Boolean, integers and strings, equality is
valid.
You can use variables in VBS without declaring the type. The context may force an implicit type
assignment. For example, if the result of a calculation is of a different type from the defined type,
the type may be changed. Always set out calculations in such a way that type changes will not
affect the final result in an undesirable or unpredictable way. If you want to change the type of a
variable or a result, use a conversion function that will show others what you intend to happen. The
conversion functions are CDbl, CInt, CLng, CSng, CStr.
WM-OM-E Rev I
289
Variable Names
Upper and lower case have no significance in VBS, either in variable names or in keywords (the
names reserved by the system), but it is a good idea to be consistent about the spelling of a
variable name to avoid confusion. At least 36 characters may be used in a variable name. These
can include any combination of alphabetic and numeric characters, and the underscore character.
No other punctuation character may be used in a variable name.
Do not use any of the following characters in a variable name:
! @ & $ # ? , * . { } ( ) [ ] = + - ^ % / ~ < > : ;
Just use alphanumerics and underscore, for example: Example_Name
If you have to introduce constants, give them sensible names, just like variables. For example, do
not write:
_If RMS < 23169 Then OutputY = Y
Its meaning may not be obvious to someone else.
It is better to write something like this:
FullScale = 32767
RootTwo = Sqr (2.0)
MaxRMS = FullScale / RootTwo
. . . . .
If RMS < MaxRMS Then . . . . .
But to keep your scripts fast, leave definitions like this outside your loops.
General usage
Note that white space has no effect, so you can introduce spaces for clarity, except of course within
variable names, function names and other keywords. Indenting control statements can be a great
help in understanding a program. For example:
For K = Kstart To Kstop
X = K * Sqr (3)
For N = NStart To Nstop
Y = N * N
If Y < FullScale Then
. . . . . .
. . . . . .
End If
Next
290
' End of main calculation
' End of N loop
WM-OM-E Rev I
X-Stream Operator’s Manual
Next
' End of K loop
If a section becomes very long, you could provide the end with a comment, to show where it comes
from.
Arithmetic Operators
As with most other languages, the arithmetic operators are used as follows:
^
Exponentiation
A ^ B = A B = A raised to the power B
/
Division
A / B = A divided by B
\
Integer division
A \ B = A divided by B, truncated to next integer below
*
Multiplication
A * B = A multiplied by B
+
Addition
A + B = B added to A
-
Subtraction
A - B = B subtracted from A
Notes:
If there is any possibility that you will be taking the exponent of a negative number, make sure to trap any possible errors
arising from such operations as trying to take the square root of a negative number. Logs of negative numbers are forbidden
also.
If there is any possibility that you will be dividing by zero, make sure to trap this.
There are two ways of dealing with these types of problem. One is to prevent it happening by making suitable tests before
the calculation is performed. The other is to let it happen, and use an error handling routine. This will be discussed later.
Normally in VBScript you will know the range of the data, since all the incoming data are, by definition, integer (unscaled
data) or real (scaled data), and they must fit into the screen of the instrument.
Results of Calculations
Sometimes you may see a statement like this:
A = A * A * (Cos (A) + Sin (A) )
The program takes the quantity represented by A and performs all of the following operations, using
that original value:
•
Multiply A by itself.
•
Calculate the cosine of A.
•
Calculate the sine of A.
•
Add the cosine and the sine together.
•
Multiply that result by the square of A.
At this point, the quantity represented by A has not been changed. Only at the end of the calculation
is the final value placed in the memory location labeled A.
Note that you can write more than one statement on a line, separated by colons, like this
A = B * Cos (34 * Theta) * Sin (55 * Theta) : B = A * A + Z * Z
WM-OM-E Rev I
291
Order of Calculations
Operations are performed in the following order:
1. Contents of brackets
2. Exponentiation
3. Division and multiplication
4. Addition and subtraction
If there is any doubt as to how the calculation will be done, use brackets. These will also make the
order of the calculations clear to any reader of the program, which is desirable if you are to give it to
a customer, who will want to know what was intended.
Here are some examples of the uses of brackets:
Brackets are worked out before any other operations are performed.
Use brackets to force the result you want, and also to clarify a calculation.
A 1 1 1 1 1 1 1 1 255 0 1 0 1 1 0 1 0 90
(B OR C) AND (D OR E)
B 1 1 1 1 0 0 0 0 240 0 0 0 0 0 0 0 0 0
B OR (C AND D) OR E
C 1 0 1 0 1 0 1 0 130 1 1 1 1 1 0 1 0 250 B OR (C AND (D OR E))
D 0 1 0 1 0 1 0 1 85
0 1 0 1 1 1 1 1 95
((B OR C) AND D) OR E)
E 0 0 0 0 1 1 1 1 15
F 00000000 0
A 7
315 A * B * (C / D) * E * F
B 6
8.75 A * B * C / (D * E * F)
C 5
35
A * B * (C / (D * E) ) * F
D 4
E 3
F 2
Check these results to see whether any errors, deliberate or otherwise, have been introduced.
These results are from file Brackets.Xls. You can make a copy of that file in order to experiment
with different combinations of brackets.
VBS Controls
Do
Do
Do
. . . .
. . . .
. . . .
292
WM-OM-E Rev I
X-Stream Operator’s Manual
Loop
Loop Until . . . .
Loop While
Do Until
Do While
Exit Do
. . . .
. . . .
Loop
Loop
For . . . Next
Exit For
GoTo__This is not allowed in instrument VBS.
If . . . . Then . . . . _' On one line__
If . . . Then
ElseIf . . . Then
End If
If . . . Then . . . End If__
If . . . Then . . . Else . . . End If
Select Case
. . . .
End Select
While
. . . .
Wend
Choose the construction that best satisfies the requirements of speed and clarity.
The construction GoTo LabelledStatement is available in many languages, including VBA, but not
in VBS. GOTO is not allowed in VBS.
IF . . . Then . . . Else . . . End If
A very simple example:
If A >= 0 Then B = Sqr (A) 'Take the square root of A if A is not negative.
If A + B < C + D Then E = F : G = H_ 'No End Is needed if all on one
line.
If you need to perform a longer procedure, make this construction:
If A >= 0 Then
B = Sqr (A)
C = 32766 * Sin ( TwoPi * B / PeriodOfSinusoid)
End If
' End If is needed to terminate the construction.
The If statement is very often used with the following Boolean expressions:
WM-OM-E Rev I
293
A>B
A is greater than B
A >= B
A is greater than B or equal to B
A=B
A is equal to B
A<B
A is less than B
A <= B
A is less than B or equal to B
A <> B
A is not equal to B
These statements are not like the usual program statements, such as A = B. These statements are
Boolean (logic) statements, which can take the values True or False. You may even see things like
"If A Then B", which means that if A is True, B gets done.
In the first example, if A is negative, we might want to write something like this:
If A >= 0 Then
B = Sqr (A)
Else
B = 0
End If
and in fact you can make some very complex constructions using If, as in the examples below:
If A < 0 Then
If A < - 1 Then
Z = 17
Else_
Z = 31
End If
Else_
If A > 3 Then
Z = 63
Else
Z = 127
End If
End If
If A > 0 Then
If B > 0 Then
294
WM-OM-E Rev I
X-Stream Operator’s Manual
Z = Y
End If
End If
This is equivalent to:
If ( (A > 0) And (B > 0) ) Then
Z = Y
End If
Summary of If . . . . Then . . . . Else
If Boolean Then AnyVBScriptingOnOneLine
If Boolean Then
AnyVBScriping
End If
If Boolean Then
AnyVBScripting
Else
AnyOtherVBScripting
End If
If you write a list like this, all the Booleans will be evaluated, whether you want that or not:
If A > 9 Then VBScripting1
If A > 7 Then VBScripting2
If A > 6 Then VBScripting3
If A > 4 Then VBScripting4
If A > 3 Then VBScripting5
If A > 1 Then VBScripting6
Be very careful when testing for equality. There will be no trouble with Integers, Long Integers, and
Strings, but Real numbers are different. Because they have so many significant digits, values that
should be equal, may differ minutely after a computation. It is safer with Real numbers to test using
a tolerance band.
File for this example: IfThenElse.xls
If you find that you are building up a rather complicated set of Ifs, you might want to consider the
Select Case construction.
Select Case
This is a very powerful construction, which is also easy to understand when written out. It is best for
WM-OM-E Rev I
295
Integers and Strings, where exact values are always obtained. Here is a simple example:
Select Case K
Case 7 : Y = 6 : Z = 3
Case 7 : Y = Sqr (Sin (A) ) : Z = Sqr (Cos (A) )
Case N : Z = Y + X
Case Else :
End Select
Case N assumes that the value of N has already been set. Case Else is included to cover other
cases, whether foreseen or not. It should always be included.
You can also provide lists of values.
Select Case K
Case 1, 2, 3, 5, 8, 13 : Y = 55 : Z = 89
Case 4, 9, 16, 25, 36 : Y = Sqr (Sin (A) ) : Z = Sqr (Cos (A) )
Case 7, 15, 31, 63, 127 : Z = Y + X
Case Else : Z = 3
End Select
Case N assumes that the value of N has already been set. Case Else is included to cover other
cases, whether foreseen or not. It should always be included.
This is very much neater than a string of Ifs and Elses, but remember: you cannot use Select Case
unless you are sure of exact equality, which allows you to compare integers and strings only. You
cannot put Case > 5, for example. File for this example: SelectCase.Xls
Summary of Select Case . . . . End Select
SelectCase VariableName
Case Alist : VBScriptingA
Case Blist : VBScriptingB
. . . .
Case Else : VBScriptingElse_ VBScriptingElse can be empty.
End Select
Do . . . Loop
This construction is useful when you do not know at programming time how many times the loop
will be executed. Here are some examples:
Do
AnyVBSCalculation
296
WM-OM-E Rev I
X-Stream Operator’s Manual
Loop Until D > Pi
Do Until Z < Y
AnyVBSCalculation
Loop
Do
AnyVBSCalculation
Loop While D <= Pi
Do While Y >=Z
AnyVBSCalculation
Loop
These constructions enable you to make the test before or after the calculation. If before, the
calculation might not be done even one time, if the condition for terminating were already true. With
the condition at the end, the calculation is done at least one time.
Sometimes you might want to exit the loop from somewhere inside: for example, if some kind of
problem is looming, such as the logarithm of a negative number.
For this case, you can use If . . . . Then Exit Do.
To make a pause of 10 seconds you can write:
NewTime = Timer + 10.0
Do Loop Until Timer >= NewTime
where Timer is a clock function in the PC, which has a resolution of one second.
Example file for these constructions: DoLoops.Xls
While . . . Wend
This is similar to Do While . . . Loop. You can write things like:
While ( (A > 2) And (C < 92677663) )
AnyVBCalculation
Wend
For . . . Next
Sometimes you know, or you think you know, the number of times that you want to do a job. For this
case a For loop is ideal, especially when you have an array of numbers to work with.
Examples:
For K = 0 To Total
HistogramBin (K) = 0
WM-OM-E Rev I
297
Next
Omega = TwoPi / Period
For N = 0 To Period
Y (N) = A * Sin (Omega * N)
Next
Be careful about changing the counting variable in any loop. You can do this to terminate the loop
early (but Exit For is better), but you could also prevent it from terminating at all.
For emergency exit, you can use Exit For. For example:
For K = 0 To Total
If HistogramBin(K) = 0 Then Exit For
AnyVBScripting
Next
It is possible to make a For loop with steps greater than 1, as in the following example in which K
takes the values 3, 7, 11, 15, . . . . 83.
For K = 3 To 82 Step 4
AnyVBScripting
Next K
You may place loops inside one another (nested loops), but they must all use different control
variables. Example:
For K = 0 To N
VBScriptingK
For L = - 7 To 17
VBScriptingL
For M = S To T
VBScriptingM
Next
Next
Next
298
WM-OM-E Rev I
X-Stream Operator’s Manual
VBS Keywords and Functions
The ones in italics do not apply to the instrument.
+
Add two values or concatenate two strings.
-
Subtract two values.
*
Multiply two values.
/
Divide two values.
\
Divide two values to obtain an integer result
Abs
Make absolute value.
Asc
Make ASCII value of a character.
Atn
Make tan-1 of a value. Result in range from -π /2
to +π /2 radians.
Cdbl
Convert a value to double precision floating
point.
Chr
Create a character from an integer in range 0 to
255.
Cint
Convert a value to nearest integer in the range
-32768 to +32767
Clng
Convert a value to nearest long integer in the
range -231 to +231 - 1.
Close
Close a file.
Cos
WM-OM-E Rev I
Make the cosine of an angle expressed in
radians.
Csng
Convert a number to single precision floating
point.
Cstr
Convert a variable to a string.
Exp
Raise e to the power of the input.
Get
Get a value from a file.
Input
Get some ASCII data from a file.
Instr
Find the position of a string in a longer string.
Int
Convert to nearest integer below the input value.
Left
Take some characters at the left end of a string.
299
Log
Take the natural logarithm of a positive value.
Ltrim
Remove spaces at the left end of a string.
Mid
Take or insert some characters in a string.
Mod
Take the modulus of a value in terms of another
value.
On Error
Take some action if an error occurs.
Open
Open a file.
Print
Send some ASCII data to a file.
Put
Randomize
Send some data to a file.
Randomize Timer re-seeds the pseudo-random
number generator.
Read
Read from a file.
Right
Take some characters at the right end of a string.
Rnd
Make a random real number in the range from
0.0 to 1.0
Rtrim
Remove spaces from right hand end of a string.
Sin
Make the sine of an angle expressed in radians.
Sqr
Make the square root of a positive number.
Str
Make a string from a numerical value.
Timer
Time since midnight in seconds, with a resolution
of one second.
Trim
Remove leading and trailing spaces from a
string.
Val
Get the ASCII value of a string beginning with
numerical characters.
Other VBS Words
Const
Dim
Redim
300
Define a constant value.
Dimension a variable.
Dimension a variable again.
Boolean
Boolean variable
Double
Double precision real variable.
WM-OM-E Rev I
X-Stream Operator’s Manual
Integer
Integer in the range -32768 to + 32767
Long
Long integer in the range -231 to + 231 - 1
Single
Single precision real variable
String
String variable
And
Or
Logical AND
Logical OR
To make a bit-by-bit comparison, logical constructions can be used with variables, as in A and B, or
with tests such as If A > B Then . . .
Functions
These are mainly of the form C = F (A), where A is the argument, or input to the function.
Abs
Abs (A) calculates the absolute value of an integer or a real number, so the result
is always positive or zero. A can be any number in the range of the VB system.
Atn
Atn (A) calculates the angle of which A is the tangent. Because infinitely many
angles can have the same tangent, the output of Atn always lies in the range
minus π / 2 to plus π / 2. The input can be any positive or negative value in the
range of the VB system.
CDbl
CDbl (A) calculates a double precision real variable, equal to A.
CInt
Cint (A) calculates the integer value nearest to A, which can be any acceptable
VBS number. Cint (-7.4) = -7. Integers are signed 16-bit values in the range
-32767 to + 32767.
CLng
Cos
CSng
Exp
Int
Log
CLng (A) calculates the nearest long integer to the value A. Long integers are
signed 32-bit values in the approximate range -21.5 M to + 21.5 M.
Cos (A) calculates the cosine of any integer or real number, giving an output that
is never greater than plus one or less than minus one.
CSng (A) calculates a single precision real variable equal to A.
Exp (A) calculates the value of eA.
Cint (A) calculates the integer value next below A, which can be any acceptable
VBS number. Int (-7.4) = -8.
Log (A) calculates the natural logarithm (to base e), of any acceptable VBS
number greater than zero. A negative number or zero will create an error.
To calculate Log10(A), use Log10(A) = Log(A) / Log(10)
Mod
A Mod (B) calculates the modulus of A, which is the remainder after A has been
divided by B.
34 Mod 8 = 2. 34 Mod 55 = 0. -34 Mod 13 = -8. 21 Mod -8 = 5.
WM-OM-E Rev I
301
Randomize
Calculates a new seed for the pseudo-random number generator.
Randomize Timer uses the real-time clock for this purpose.
Sin
Sin (A) calculates the sine of any integer or real number, giving an output that is
never greater than +1 or less than -1.
Sqr
Sqr (A) calculates the square root of any integer or a real number that is not
negative. If A is negative, an error will occur.
Timer
Time since the previous midnight in whole seconds.
Hints and Tips for VBScripting
Set the trigger to Single or Stopped if you need to do a lot of editing: it is faster.
Before starting a script, remove any existing scripts that you do not need. This is because errors in
an existing script will give you error messages, even if your current script is perfect. And an existing
good script may develop a fault if you change the setup. For example, you might change the vertical
scale or the memory length and get an overflow if you did not guard against it in the script.
When starting a script, make sure that you have chosen the right kind: function or parameter. You
can get some very frustrating problems if you are in the wrong mode. You can cut and paste the
VBS statements if you discover this error.
If your calculation requires a long memory, development might be quicker if you test the principles
on a shorter trace at first.
Note that the pseudo-random number generator is reset at the start of a script. If you want a
different set of pseudo-randoms every time, put Randomize Timer in the program, to be run once,
before any pseudo-randoms are generated. You can use this instruction to re-seed the generator at
any time during execution.
Do not put the final statement in a loop, hoping that you can see a progressive result as some
parameter changes. No output will be seen on the screen of the instrument until the script has been
completely run and quitted, so only the final result will appear. If the loop runs many times, you will
think that the scope has hung up.
If you want a For loop, end it with "Next" and not "Next X".
If you make a script that takes a long time to run, go back to the default setup before quitting or
powering down, or you will have a long wait next time you power up.
Always use a recursive calculation when this will speed things up.
Keep everything outside a loop that does not have to be inside, to speed things up.
Make your scripts clear, not only by indenting and commenting, but by structuring neatly as well.
Sometimes it might be easier to develop your script in Excel VBA (remembering that VBA is not
identical to VBS), so that you can display intermediate results. If you do this, note that you can read
from a cell or write to it using statements like these:
A = Worksheets("Sheet1").Cells(Row, Column).Value
302
WM-OM-E Rev I
X-Stream Operator’s Manual
Worksheets("Sheet1").Cells(Row, Column).Value = B
Note that in VBS, after you have corrected an error and clicked on "Apply," the error message may
go on flashing for a few seconds, or a few acquisitions, before being erased. Look for the "Script
OK" message. Be patient before assuming that you still have a bug.
If your calculation requires data to be used at some other horizontal positions than their original
ones, make sure that your algorithm does not try to send data to non-existent array positions, that is,
beyond the edges of the screen. You may have to truncate your output trace, as happens with the
instrument's Enhanced Resolution and Boxcar functions.
No output will emerge from a script until you press Apply.
No output will emerge from a script until it has received an input. This includes the case where the
input data are not used in calculating the output data. So you must have had at least one acquisition
before you see anything.
Because you can introduce undeclared variables at any point in a calculation, VBS does not check
your spelling.
You can make a portion of a trace disappear if you set the values to 32767 or -32768.
You can highlight a section of a trace by making the points alternately too high and too low by a
suitable amount. Providing the memory length is not too short, the compaction algorithm will give
the effect of a thicker trace.
The lengths of the output trace and the input trace need not be the same. You can even make the
output trace longer than the input trace, but you will need to unzoom it to see it all. This feature can
be used to avoid compaction problems with non-linear horizontal scales. It can also be used to
show several versions of a function at the same time, without having to set up a separate script for
each one.
If your program structure is complicated, consider typing all the IFs, ELSEIFs, ENDIFs, FORs,
NEXTs, etc and then clicking Apply. You wont get any output, but the system will tell you if the
structure is acceptable. Then you can insert the actual program statements.
Always try to make the script as independent as possible of variables such as V/Div, T/Div, and
memory length, unless that would make it harder to understand. If so, give some values as
examples, and explain how the script would have to change if the variables changed.
Errors
The instrument VBS tries hard to help you when errors occur.
Errors may be of two main types:
•
The script may not be usable because the interpreter cannot construct a logical structure
from it.
•
The script may be usable, but may fail while running because an incomputable function has
been requested.
Sometimes the line number given for an error is wrong. This can happen when the error is of this
general type:
WM-OM-E Rev I
303
Missing "Next" Missing "End If"
Extra "Next" Missing "Until" etc.
This happens because VBS cannot know where you should have put the statement.
If at some point during the calculation of an output array, a value goes outside the allowed range,
the calculation will stop, and you will see the new values up to the point of the stoppage. To the right
of that point, the trace will display the previous values. In fact, if you deliberately recalculate only a
part of a trace, you can have a mixture of new and old values.
In the figure below is a type of error message that you may see if one of your calculations has tried
to set a value outside the range -32768 to +32767. It takes extra time to guard against this, but
unless you are sure that it will not happen, you need some kind of check. In the example on the next
page, the red trace has gone outside the allowed range at the beginning, resulting in the message
at the bottom of the instrument screen: This array is fixed or temporarily locked:
OutResult.DataArray.
304
WM-OM-E Rev I
X-Stream Operator’s Manual
Error Handling
Note that the construction OnError GoTo Label: is not allowed in VBS. In fact no GoTos or labels
are allowed. Therefore there is no way for you to provide handlers to deal with errors and
exceptions. You must be aware of all possibilities at all points in your program, and you must either
be certain that errors will not occur, or you must take action to ensure that they do not.
Examples:
Sqr
You cannot take the square root of a negative
number.
Log
You cannot take the log of zero or of a negative
number.
A/B
You cannot divide by zero.
Array
You cannot use an index outside the bounds of
an array.
Size
Unscaled data cannot go outside the range
-32768 to 32767.
If there is any possibility that any of these might occur, take steps to deal with this before it can
happen.
For example, you may write some kind of generator of pseudo-random statistical values. If these
belong to a distribution that in principle has an infinite range, or a finite range which is wider than the
signed 16-bits allowed, check each value. If a value falls outside the range, you could set it to the
maximum or generate another example.
You can, however, use one of the following:
On Error Resume Next
followed by some code that may make some attempt to deal with the problem, or at least to allow
execution to continue.
On Error GoTo 0
This cancels On Error Resume Next_
Speed of Execution
To maximize the speed of execution of a script, the most important thing you can do is to minimize
the number of operations that are performed inside loops. Anything done once only is unlikely to be
an important source of delay. Please note that VBS is much slower than the internal computations
of the instrument, so do everything you can to save time, unless time is irrelevant to the application.
Using an array element takes longer than using a single variable. Here is an example:
For K = 1 to Total
If X (K) > X (K - 1) Then
Y = Cos (X (K) ) * Sin (X (K) ) * Sqr (X (K) )
WM-OM-E Rev I
305
End If
Next
To do the same thing we could also write this, using the index only once:
OldXK = X (0)
For K = 1 To Total
XK = X (K)
If XK > OldXK Then
Y = Cos (XK) * Sin (XK) * Sqr (XK)
OldXK = XK
End If
Next
VBS runs slower than the "internal" calculations, because the scripts are interpreted. This could be
serious for calculations where many operations are needed on each sample, such as convolution,
correlation, and long digital filters.
Scripting Ideas
What can we do in a VBS script that we cannot do with the normal instrument functions? Here are
some possibilities.
•
Create a new function that acts on waveform values.
•
Create a new parameter.
•
Create a new form of non-linear vertical scale.
•
Create a new form of non-linear horizontal scale.
•
Move some or all data horizontally, including reflections.
•
Combine data to form digital filters.
•
Show several function results side by side.
•
Show several function results interleaved.
You can even create output data that are not related to the input. The output data need not even be
in the same domain as the input data, because the system treats them as pure numbers. So you
can create your own transforms into the frequency domain, for example.
306
WM-OM-E Rev I
X-Stream Operator’s Manual
Debugging Scripts
Until we have integrated a more comprehensive debugger for VBScript there is a workaround.
1. Download the Windows Scripting Debugger for Windows 2000 from here:
http://download.microsoft.com/download/winscript56/Install/1.0a/NT45XP/EN-US/scd10e
n.exe
2. Enable JIT (Just In Time) debugging by setting the following registry key
HKCU\Software\Microsoft\Windows Script\Settings\JITDebug = to 1 (DWORD value)
3. Place a Stop statement in your script.
Now, when the Stop statement is executed the debugger will open and allow single-stepping,
variable examination, etc.
Using VBA or Visual Basic to debug VBScripts is not recommended since the language syntax for
these three variants of basic is slightly different.
Horizontal Control Variables
InResult.HorizontalOffset
Double precision
Time shift of input waveform on grid in units of
horizontal scale
OutResult.HorizontalOffset
Double precision
Time shift of output waveform on grid in units
of horizontal scale
InResult.HorizontalPerStep
Double precision
Time between successive samples in the input
waveform
OutResult.HorizontalPerStep Double precision Time between successive samples in the
output waveform
InResult.HorizontalUnits
String
Horizontal units of input waveform
OutResult.HorizontalUnits
String
Horizontal units of output waveform
InResult.Samples
Integer
Number of samples in input waveform
Vertical Control Variables
InResult.VerticalOffset
Double precision Vertical shift of input waveform on grid
OutResult.VerticalOffset
Double precision Vertical shift of output waveform on grid
InResult.VerticalPerStep
Double precision Difference between successive possible levels
in the input waveform memory
OutResultVerticalPerStep
Double precision Difference between successive possible levels
in the output waveform memory
1 / 65536 of vertical full scale
WM-OM-E Rev I
307
InResult.VerticalResolution
Double precision Difference between successive possible
physical levels in the input waveform
OutResultVerticalResolution Double precision Difference between successive possible
physical levels in the output waveform
1 / 256 of vertical full scale for channel
waveforms
1 / 65536 of vertical full scale for math
waveforms
InResult.VerticalUnits
String
Vertical units of input waveform
OutResult.VerticalUnits
String
Vertical units of output waveform
List of Variables Available to Scripts
FirstEventTime([out, retval] VARIANT * pVal); FirstEventTime([in] VARIANT newVal);
LastEventTime([out, retval] VARIANT * pVal); LastEventTime([in] VARIANT newVal);
UpdateTime([out, retval] VARIANT * pVal); UpdateTime([in] VARIANT newVal);
Details([in] BSTR strDetailsIID, [out, retval] VARIANT * pVal);
Status([out, retval] VARIANT * pVal); Status([in] VARIANT newVal);
ExtendedStatus([out, retval] VARIANT * pVal); ExtendedStatus([in] VARIANT newVal);
StatusDescription([out, retval] BSTR * pVal); StatusDescription([in] BSTR newVal);
DataArray([in, defaultvalue(TRUE)] BOOL arrayValuesScaled,
[in, defaultvalue(LEC_ALL_DATA)] int numSamples,
[in, defaultvalue(0)] int startIndex,
[in, defaultvalue(1)] int sparsingFactor,
[out, retval] VARIANT *pArray);
DataArray([in, defaultvalue(TRUE)] BOOL arrayValuesScaled,
[in, defaultvalue(LEC_ALL_DATA)] int numSamples,
[in, defaultvalue(0)] int startIndex,
[in, defaultvalue(1)] int sparsingFactor,
[in] VARIANT array);
HorizontalUnits([out, retval] BSTR *pVal); HorizontalUnits([in] BSTR newVal);
Samples([out, retval] int *pVal); Samples([in] int newVal);
HorizontalResolution([out, retval] double *pVal); HorizontalResolution([in] double newVal);
HorizontalPerStep([out, retval] double *pVal); HorizontalPerStep([in] double newVal);
308
WM-OM-E Rev I
X-Stream Operator’s Manual
HorizontalOffset([out, retval] double *pVal); HorizontalOffset([in] double newVal);
Sweeps([out, retval] int *pVal); Sweeps([in] int newVal);
HorizontalVariances([out, retval] int *pVal); HorizontalVariances([in] int newVal);
HorizontalVarianceArray([out, retval] VARIANT * pArray);
HorizontalVarianceArray([in] VARIANT array);
HorizontalFrameStart([out, retval] double *pVal); HorizontalFrameStart([in] double newVal);
HorizontalFrameStop([out, retval] double *pVal); HorizontalFrameStop([in] double newVal);
VerticalFrameStart([out, retval] double *pVal); VerticalFrameStart([in] double newVal);
VerticalFrameStop([out, retval] double *pVal); VerticalFrameStop([in] double newVal);
VerticalResolution([out, retval] double *pVal); VerticalResolution([in] double newVal);
VerticalPerStep([out, retval] double *pVal); VerticalPerStep([in] double newVal);
VerticalOffset([out, retval] double *pVal); VerticalOffset([in] double newVal);
VerticalMinPossible([out, retval] double *pVal); VerticalMinPossible([in] double newVal);
VerticalMaxPossible([out, retval] double *pVal); VerticalMaxPossible([in] double newVal);
VerticalUnits([out, retval] BSTR *pVal); VerticalUnits([in] BSTR newVal);
Communicating with Other Programs from a VBScript
The ability of The instrument to communicate with other programs opens up immense possibilities,
both for calculation and for graphics, making the assembly of reports relatively simple.
Communicating with Excel from a VBScript
Although there are direct instrument calls to Excel and other programs, you may wish to do this
from a VBScript. Here is an example:
OutResult.Samples = InResult.Samples
startData = 0
endData = OutResult.Samples
ReDim newData(OutResult.Samples)
USD = InResult.DataArray(False)
LastPoint = endData - 1
Set ExcelApp = GetObject(,"Excel.Application")
ExcelApp.Visible = True
ExcelColumnA = 2
'Column where the data will appear in Excel
ExcelRow = 10
'Row where the data will start
ExcelColumnB = 3
' Column where the output data will appear in Excel
WM-OM-E Rev I
309
For K = 0 To LastPoint
ExcelApp.ActiveSheet.Cells("ExcelRow + K, ExcelColumnA ") = -USD(K)
Next
Once the data are in Excel, any Excel functions can be applied to the data.
The results can be returned to the VB script.
For K = 0 To LastPoint
NDA(K) = ExcelApp.ActiveSheet.Cells("ExcelRow + K, ExcelColumnB")
Next
Transferring data cell by cell is very slow, so it is better to do a block transfer.
310
WM-OM-E Rev I
X-Stream Operator’s Manual
Calling MATLAB from the Instrument
Calling MATLAB
Note: Load MATLAB version 6.5 just as you would on any PC. Once it is loaded, open MATLAB from the desktop, then
close it again, before you attempt to open it from the instrument application. This is to update the registry.
MATLAB can be directly called from the instrument in two ways:
Using a function
F1 through Fx The number of
math traces available depends
on the software options loaded MATLAB returns a waveform
on your scope. See
Specifications.
Using a parameter
P1 through Px
MATLAB returns a parameter
In both cases, one call to MATLAB can use two separate waveforms as input, providing much
greater computing power than is available by calling MATLAB from a VBScript.
Note: If you do not place a semicolon ";" at the end of a line, MATLAB will show the calculated value in the result window,
significantly slowing down the processing rate. This feature is best kept for diagnostics.
How to Select a Waveform Function Call
The MATLAB Waveform functions are selected from the Select Math Operator menu. Please note
that once you have clicked on "MATLAB Wave" there will be a slight pause before MATLAB starts.
WM-OM-E Rev I
311
Source 1 and Source 2 are the waveforms that MATLAB will use.
The MATLAB Waveform Control Panel
Once you have invoked a MATLAB waveform call, you will see the zoom dialog at the right of the
screen. Touch the MATLAB tab to see a panel like this:
Touch Find Scale to make your output fit the grid, or use the text boxes to choose a scale.
MATLAB Waveform Function Editor -- Example
By touching Edit Code, you can reach the MATLAB Editor where you will see the default waveform
function. If you are familiar with MATLAB, you might prefer to launch MATLAB and create a
MATLAB function that performs your task. Your program in the instrument could then be a one-line
call of your MATLAB function.
312
WM-OM-E Rev I
X-Stream Operator’s Manual
This is the default waveform function, with one important change: the semi-colon (;) has been
removed from the end of the line. If the semicolon is present, your function will run much faster,
because the output values will not be shown in MATLAB Response. With a long waveform, the time
needed to display it could be quite long. The response values can be useful during development
and debugging. Any line without a semicolon will produce a visible MATLAB Response.
From this panel you can save your code, load a previous code, and edit your function. A powerful
feature of MATLAB is that you can refer to an entire waveform as a vector. The two input
waveforms are WformIn1 and WformIn2, while the output is WformOut. You can also refer to
individual samples, such as WformIn1(34), and sequences of samples, such as WformIn(55:89)
You can write statements such as these:
WformOut(5) = WformIn(5)
WformOut(89) = WformIn(144)
WformOut(34:55) = WformIn(34:55)
WM-OM-E Rev I
313
WformOut(233:377) = WformIn(100:244)
This very simple example adds a rescaled copy of Channel 2 to a copy of Channel 1, and then
rescales the result.
314
WM-OM-E Rev I
X-Stream Operator’s Manual
MATLAB Example Waveform Plot
If you touch the MATLAB Plot checkbox you will see a MATLAB plot like this one:
WM-OM-E Rev I
315
How to Select a MATLAB Parameter Call
Menu position for MATLAB parameter call in Select Measurement menu.
The MATLAB Parameter Control Panel
Once you have invoked a MATLAB parameter call, a mini-dialog to the right of the main dialog will
appear:
You can touch the MATLAB Plot checkbox if you want to see a plot in MATLAB as well as getting
316
WM-OM-E Rev I
X-Stream Operator’s Manual
a result in the instrument.
The MATLAB Parameter Editor
By touching Edit Code, you can reach the MATLAB Editor:
This simple example shows the MATLAB function Standard Deviation acting on input channel 1,
and the result would be shown in the MATLAB Response pane for an amplitude of 0.15 volt.
You can load an existing MATLAB program, using the Load Code button, and you can save the
current program, using the Save Code button.
If you are familiar with MATLAB you might prefer to launch MATLAB and create a MATLAB function
that performs your task. Your program in the instrument could then be a one-line call of your
MATLAB function.
WM-OM-E Rev I
317
MATLAB Example Parameter Panel
The next example calculates the ratio of the number of data points that are above a given level to
the number of points below the level, in this case one half of the amplitude.
318
WM-OM-E Rev I
X-Stream Operator’s Manual
Further Examples of MATLAB Waveform Functions
Negate the input signal.
WM-OM-E Rev I
319
Square the input signal.
Create pulses from a sinusoid.
Create pulses at the zero crossings of the signal.
320
WM-OM-E Rev I
X-Stream Operator’s Manual
Convolve two signals.
Creating your own MATLAB function
The procedure is simple. Create a MATLAB function using any text editor, and save it as a
MATLAB m-file by giving it a name of the form Filename.m. Call the function using the MATLAB
math editor or the MATLAB parameter editor as appropriate. A simple example is shown below.
function out = negatewf(wf1)
% NEGATEWF changes the sign of all the data.
out = -wf1;
WM-OM-E Rev I
321
322
WM-OM-E Rev I
X-Stream Operator’s Manual
CUSTOMDSO
Custom DSO
Introduction - What is CustomDSO?
CustomDSO, in its Basic mode, allows you to create DSO setups that can be called by the touch of
a single button. The recalled setups can themselves include calls to other setups. A very simple
example would be a toggle between two setups. Rings of three or more setups are possible, as are
trees, or any other topology that you need. Basic mode also allows you to recall VBScripts that can
set up all or part of the scope and do many other things.
Another more powerful feature is the PlugIn, which allows you to add your own ActiveX controls to
a setup. These controls are powered by routines written in Visual Basic. With ActiveX controls you
can create your own user interfaces to suit your own preferences. A large number of interactive
devices are available: button, checkbox, radio button, list box, picture box, and common dialogue
box.
Invoking CustomDSO
CustomDSO can be invoked from the Analysis drop-down menu:
If CustomDSO is already in Basic mode, the following dialog will be displayed:
WM-OM-E Rev I
323
CustomDSO Basic Mode
The Basic CustomDSO mode offers eight Action buttons, each of which can call a different setup
when touched. The "Action Definition" dialog is used to enter a CustomDSO setup file name by
means of the pop-up keyboard.
By clicking the checkbox
, the eight CustomDSO
buttons will continue to be available at the bottom of the screen after you close the CustomDSO
dialog. Furthermore, they will appear automatically each time the scope is powered up.
Editing a CustomDSO Setup File
; a dialog will appear for you to create
If the file does not exist, touch the Edit button
the file. If the file does already exist, the Edit button enables you to modify it. The Edit button allows
you to edit the file that is named in the Setup file to recall field, and not the file of the setup that the
instrument is currently in, unless these happen to be the same.
In the example used here, three setup files were made, called CustomA.lss, CustomB.lss and
CustomC.lss. Fragments from all three are shown below.
1160 Set CustomDSO = XStreamDSO.CustomDSO
1161 ‘ CustomDSO Setup A.lss
324
WM-OM-E Rev I
X-Stream Operator’s Manual
1162
1163
1164
1165
1166
1167
1168
1169
CustomDSO.ActionScript1
CustomDSO.ActionEnable1
CustomDSO.ActionScript1
CustomDSO.ActionEnable1
CustomDSO.ActionScript1
CustomDSO.ActionEnable1
CustomDSO.ActionScript1
CustomDSO.ActionEnable1
=
=
=
=
=
=
=
=
“c:\LeCroy\XStream\CustomDSO\A.lss”
False
“c:\LeCroy\XStream\CustomDSO\B.lss”
True
“c:\LeCroy\XStream\CustomDSO\C.lss”
True
“c:\LeCroy\XStream\CustomDSO\A.lss”
False
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
Set CustomDSO = XStreamDSO.CustomDSO
‘ CustomDSO Setup B.lss
CustomDSO.ActionScript1 = “c:\LeCroy\XStream\CustomDSO\A.lss”
CustomDSO.ActionEnable1 = True
CustomDSO.ActionScript1 = “c:\LeCroy\XStream\CustomDSO\B.lss”
CustomDSO.ActionEnable1 = False
CustomDSO.ActionScript1 = “c:\LeCroy\XStream\CustomDSO\C.lss”
CustomDSO.ActionEnable1 = True
CustomDSO.ActionScript1 = “c:\LeCroy\XStream\CustomDSO\A.lss”
CustomDSO.ActionEnable1 = False
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
Set CustomDSO = XStreamDSO.CustomDSO
‘ CustomDSO Setup C.lss
CustomDSO.ActionScript1 = “c:\LeCroy\XStream\CustomDSO\A.lss”
CustomDSO.ActionEnable1 = True
CustomDSO.ActionScript1 = “c:\LeCroy\XStream\CustomDSO\B.lss”
CustomDSO.ActionEnable1 = True
CustomDSO.ActionScript1 = “c:\LeCroy\XStream\CustomDSO\C.lss”
CustomDSO.ActionEnable1 = False
CustomDSO.ActionScript1 = “c:\LeCroy\XStream\CustomDSO\A.lss”
CustomDSO.ActionEnable1 = False
The text in green following a single quotation mark is a VBS comment and causes no action.
The text in red contains the path and name of the setup file associated with the numbered button.
This setup will be called when the button is pressed.
The Boolean (in blue) decides whether the action button will invoke the setup or remain inactive.
For example, in setup B, A.lss and C.lss can be invoked, but not B, which is already in place.
As you see from the line numbers in the program fragments, the setup files are rather long because
they include all the information needed to set the scope to the required state. But if you want to
make a very short file that changes only a few variables (for example, the action button settings)
you can make a file that includes only the relevant instructions. This usage assumes that the
remainder of the scope is already in the required state. This is an example of the complete
compatibility of the instrument's software. The same commands can be used in setups, in scripts,
or in remote control commands in external programs, whether resident in the instrument or in an
external computer.
WM-OM-E Rev I
325
Creating a CustomDSO Setup File
If you touch the Edit button
when the Setup file to recall field contains the name of
a non-existent file, you will see a message like this:
If you then touch Yes, the scope will display a file like this:
' XStreamDSO ConfigurationVBScript ...
' Created by CustomDSO ...
On Error Resume Next
set dso = CreateObject("LeCroy.XStreamDSO.1")
' dso.Display.GridMode = "Dual"
' dso.Acquisition.C1.VerScale = 0.1
' dso.Acquisition.Horizontal.HorScale = 1e-6
' dso.Acquisition.TriggerMode = "Auto"
You can add to this fragment any commands you need.
CustomDSO PlugIn Mode
This is the mode in which CustomDSO really shows its power. You can insert any ActiveX control or
graph.
Creating a CustomDSO PlugIn
Follow these steps to create an example Visual Basic PlugIn:
1. Start a new VB project. Select ActiveX Control from the New tab.
2. Resize the control. A. In the Properties window set Width 11940. B. In the Properties
window set Height 2475.
3. Place two buttons on the control.
A. Double click on the command button at left of screen (left arrow below).
B. Move and resize the resulting button as required, using the handles (right arrow below).
326
WM-OM-E Rev I
X-Stream Operator’s Manual
C. Repeat for the second button. D. In the Properties window set the Name properties to
SingleButton and AutoButton, respectively. E. Set the button Caption properties to
Single and Auto, respectively
4. Create code for the buttons. A. Double click on the Single button. B. In the resulting code
window, insert code to make the following subroutine:
Private Sub SingleButton_Click()
Dim app as Object
Set app = CreateObject(“LeCroy.XStreamApplication”)
app.Acquistion.TriggerMode = “Stopped”
End Sub
Double click on the Auto button.
In the resulting code window, insert code to make the following subroutine:
Private Sub AutoButton_Click()
Dim app as Object
Set app = CreateObject(“LeCroy.XStreamApplication”)
app.Acquistion.TriggerMode = “Auto”
End Sub
5. Test the Component in Internet Explorer. (This is an optional, but very useful step, because
you can test your work without installing anything in the instrument.) A. Start the instrument.
B. Click the Run button In Visual Basic. C. Click the Stop button in Visual Basic when you
have finished.
6. Make the Project in Visual Basic. A. Click the Stop button in Visual Basic. B. Select Make
WM-OM-E Rev I
327
Project1.ocx from the File menu.
7. Install the PlugIn in the instrument. A. Start the instrument. B. Select ActiveDSO in the
Analysis Menu. C. Select PlugIns mode. D. Type “Project1.UserControl1” in the “COM
ProgID of Plug-In” text box. E. Click the Install button under the text box.
8. Now Click the new Auto and Single buttons to see their effects.
Properties of the Control and its Objects
Using the View Properties button in Visual Basic, you can customize your PlugIn to your exact
requirements. Among the most useful properties are the following: Height, Width, BackColor, Name,
Caption.
You can gain access to the properties of your objects by Clicking View - Properties. Positions and
sizes of objects can be changed from View - Object, by dragging the object or one of its handles.
You can insert any available control into your plug-in. The basic control set is shown in a toolbar at
the left of the screen in the picture below. Double click on any control to insert it into the plug-in. In
the following example, a command button has just been inserted.
In the next example you can see a command button, a picture box, a list box and a Tabbed Dialog
Control.
328
WM-OM-E Rev I
X-Stream Operator’s Manual
The Tabbed Control (arrow) is not in the basic tool box. To gain access to it, right click in the tool
box at left (but not on an icon.) You will see this menu:
Now select the Microsoft Tabbed Control as shown below, and click on Apply. The control will be
added into the toolbox at the left of the screen, where you can double click on it as usual.
WM-OM-E Rev I
329
The new control is shown below (arrow).
The system is very versatile, and you can place controls on the tabs of the Tabbed Control. Look in
the properties window to see how you can customize your tabs, as illustrated below.
330
WM-OM-E Rev I
X-Stream Operator’s Manual
Removing a PlugIn
To remove a plug-in, click on Remove in the PlugIn dialog, as shown below:
Close the CustomDSO dialog and reopen; the plug-in will vanish.
First Example PlugIn - Exchanging Two Traces on the Grids
The example assumes that the instrument is in dual-grid mode, and that there are at least two
visible traces. The routine looks for the visible traces, in the order C1 . . . C4, F1 . . . . Fx The number
of math traces available depends on the software options loaded on your scope. See
Specifications., and it exchanges the first two it finds whenever the button is pressed. Note that
arrays of objects can be constructed, allowing numerous objects to be accessed in simple loops.
WM-OM-E Rev I
331
Private Sub Command1_Click()
Dim wm As Object
Set wm = CreateObject("LeCroy.XStreamApplication")
Set acq = wm.Acquisition ' To save typing
Set mat = wm.Math
' To save typing
Dim t(16) As Object
‘ Create an array of objects to allow looping.
Set t(1) = acq.C1 : Set t(2) = acq.C2
Set t(3) = acq.C3 : Set t(4) = acq.C4
Set t(5) = mat.F1 : Set t(6) = mat.F2
Set t(7) = mat.F3 : Set t(8) = mat.F4
Set t(9) = mat.F5 : Set t(10) = mat.F6
Set t(11) = mat.F7 : Set t(12) = mat.F8
Dim trace As Integer
trace = 0: views = 0
' Exchange the traces on the grids.
Do
trace = trace + 1
If t(trace).View = "True" Then
views = views + 1
If t(trace).UseGrid = "YT1" Then
t(trace).UseGrid = "YT2"
Else
t(trace).UseGrid = "YT1"
End If
End If
Loop Until ((trace = 12) Or (views = 2))
' Show the parity of the last swap.
If Command1.Caption = "Swap A" Then
Command1.Caption = "Swap B"
Else
Command1.Caption = "Swap A"
End If
Dim TextString As String
TextString = Text1.Text
Dim TextValue As Integer
TextValue = Val(TextString) + 1
TextString = Str(TextValue)
TextString = Trim(TextString)
Text1.Text = TextString
End Sub
This routine exchanges the first two traces that it finds. You can make it exchange all the traces on
a dual grid by changing the penultimate line to this - Loop Until trace = 12
332
WM-OM-E Rev I
X-Stream Operator’s Manual
The next figure shows the Visual Basic Screen just after the Text Box text has been set to “0” in the
Properties Window, thus defining the initial value.
Here is the result after seven swaps. The counting method could be useful in any routine where
numerous operations, such as triggers, have to be performed. In fact, the caption of the button
could have been used to show the number of operations.
ActiveX offers a large range of standard controls, including list boxes for selection from a list, and
picture boxes for drawing graphs and charts.
WM-OM-E Rev I
333
Second Example PlugIn - Log-Log FFT Plot
A frequent requirement is to plot a frequency spectrum on two logarithmic scales. The instrument
provides a vertical scale, so CustomDSO has only to change the horizontal one. Here is an
example. The first figure has been truncated on the right side.
These examples were made with two different instrument setups: in the second, the FFT was
zoomed vertically. The graph has a red line to represent the theoretical envelope for the peaks.
This has great potential for testing the transmission characteristics of amplifiers and filters, since
the output can be compared with a theoretical curve. Furthermore, if the output is divided by the
334
WM-OM-E Rev I
X-Stream Operator’s Manual
curve, the result for a perfect DUT would be a horizontal line, which is easy to inspect. The example
below has been magnified vertically by a factor of ten. The rise at the right side occurs because the
signal is descending into the noise.
Private Sub Command1_Click()
'
Draw a DSO trace on a logarithmic horizontal scale.
Dim WM As Object
Set WM = CreateObject("LeCroy.XStreamApplication")
Dim Samples As Long
Samples = WM.Math.F1.Out.Result.Samples
Samples = Samples - 1 ' Make it a round number.
'
Calculate the horizontal scale.
LogSamples = Log(Samples)
XScale = Samples / LogSamples
'
Set the scale using DSO variables
Dim Top, Bot As Single
Top = WM.Math.F1.Out.Result.VerticalFrameStop
Bot = WM.Math.F1.Out.Result.VerticalFrameStart
Picture1.Scale (0, Top)-(Samples, Bot)
Dim Wave
Wave = WM.Math.F1.Out.Result.DataArray
Dim Black, White, Blue, Red As Long
Black = 0: White = &HFFFFFF
Blue = &HFF4444: Red = &HFF
'
Draw a theoretical curve for the peaks.
StartPoint = Top + 20#: EndPoint = -54.5
Picture1.Line (0, StartPoint)-(Samples, EndPoint), Red
'
Draw the plot with linear interpolation between points.
For X = 1 To Samples
LogX = XScale * Log(X): Y = Wave(X)
If X > 1 Then
Picture1.Line (LogX, Y)-(OldLogX, OldWave), Black
WM-OM-E Rev I
335
End If
OldLogX = LogX: OldWave = Y
Next X
End Sub
Here is an example showing a simple one-pole roll-off compared to a curve.
Control Variables in CustomDSO
The simplest way to select variables for use in CustomDSO is to use LeCroy’s X-Stream Browser.
336
WM-OM-E Rev I
X-Stream Operator’s Manual
LABNOTEBOOK
Introduction to LabNotebook
LeCroy's LabNotebook feature extends the documentation capabilities of your scope. It allows you
to create an annotated notebook entry containing all displayed waveforms, the setup of the scope,
and user-supplied annotation. The notebook entry can then be converted to hardcopy format -- pdf,
rtf, or html -- and printed or e-mailed. You can also use the default report layout or configure your
own, and even substitute your own company logo in the header.
Notebook entries are stored in an internal database and are available for recall at any time. Besides
storing the waveform data, LabNotebook also stores your panel setups and parameter
measurements. You have the capability to back up the database to external media.
The Flashback feature allows you to recall the state of the scope at a later date, including the saved
waveforms and the scope setup, so that you can make additional measurements. A keyword filter
makes it easy to find the correct notebook entry to recall.
You can choose which notebook to use for your entries, and label the notebook by project or user.
If the scope is shared among several users, for example, or used for different projects, the data can
be kept separately. Similarly, hardcopy reports can be stored in different folders.
Preferences
You should set your preferences before creating notebook entries.
Miscellaneous Settings
You can elect to name notebook entries with the default date
and time by leaving the top box unchecked. Check the box if
you want the opportunity to rename the notebook entry as
soon as it is created.
Check the middle box if you want to be able to annotate a
notebook entry as soon as it is created.
Check the last box if you want to generate a notebook entry
by simply touching the Hardcopy (Print) front panel button
. By checking this box, you override any other
configuration for this button; for example, send e-mail or
output to printer.
Hardcopy Setup
Check the Use Print Colors checkbox to place your
waveforms on a white background in the notebook entry. This
will save printer ink later when you print the hardcopy report.
Touch inside Hardcopy Area to determine how much of the
screen image to include in the report: grid area only, grid area
plus dialog, whole screen.
WM-OM-E Rev I
337
E-mail Setup
You can e-mail just the pdf or html report; or, you can include
additional files: trace data (.trc) for each waveform in the
report, a screen dump, a scope setup file, and an xml report
record. Touch the checkbox to enable the extra report
segments.
Touch the Configure E-Mail button to set the recipient
address and server information.
Creating a Notebook Entry
1. Touch File in the menu bar, then Create Notebook Entry in the drop-down menu:
.
A dialog box is displayed in which to enter a title and comments for the entry. By default, the
entry is titled with the current date and time:
338
WM-OM-E Rev I
X-Stream Operator’s Manual
2. Touch inside the Title field and enter a title, using the pop-up keyboard. Then touch inside the
Description field and enter a description, if desired, and touch Close.
The notebook entry will display your waveforms in "print colors," that is, on a white background to
save printer ink, if you selected that option in notebook Preferences. Otherwise, the waveforms will
appear on a black background. A drawing toolbar appears at top:
The pen tool enables you to write or draw in freehand. You can use a mouse,
or a stylus to do this using the touch screen. Once you click off, you can drag
your note anywhere on your waveform.
The circle tool enables you to create a circle around a waveform feature that
you want to point out. Once you click off, the circle is drawn and you can drag
it anywhere on the screen.
The arrow tool enables you to draw lines with arrowheads for callouts. You
can rotate these lines through 360 degrees and drag them to any location on
the screen.
The text tool enables you to enter text callouts on your report. When you touch
this tool, a dialog box opens in which to enter text by means of a pop-up
keyboard:
After you touch Close, your text will appear on the display as a draggable
object.
These are the three default colors that you can select for shapes, lines, and
text. To use additional colors, touch More.
WM-OM-E Rev I
339
When you touch More, a Custom box opens with the default color yellow
displayed. Touch the yellow button to open the full color palette:
When you have chosen a custom color, touch Add to Custom Colors; the
color will appear in the Custom Colors palette:
Then touch the color to enable it, and touch OK. The next object that you
create will be in that color.
If you want to erase a drawing object, touch it to select it, then touch Erase
Selected.
Touch Erase All to erase all drawn objects and text.
340
WM-OM-E Rev I
X-Stream Operator’s Manual
Touch Undo to discard the last object drawn.
The Move Toolbar button enables you to place the toolbar anywhere on the
screen. Touch the button a second time to return it to its original fixed location.
Touch Done when you are finished annotating the notebook entry. The name
of the entry will appear in the list box in the "LabNotebook" dialog. You can
now create a hardcopy report of it, and email or print it out.
Recalling Notebook Entries
After a notebook entry is made, you can recall it at any time. The recall includes waveforms and
scope settings.
WM-OM-E Rev I
341
1. Select the notebook entry from the list box.
2. Touch Flashback.
3. To exit Flashback, touch the Undo Flashback button in the top-right corner of the screen, or
press the Auto trigger button.
Note: The flashback feature currently recalls the scope setup, and all displayed waveforms. Some forms of ‘result data’ are
not recalled, including:
a. Persistence data. This will be saved in the hardcopy, and will be printed in the report, but will not be recalled during
Flashback.
b. Histogram data. Histograms internally have a 32-bit resolution, but when stored into a trace file and recalled during
flashback they are clipped to 16-bits.
c. Floating point waveforms. Certain math operations result in the creation of floating point waveforms with much higher
resolution than can be stored in a 16-bit waveform file. This extra resolution will not be preserved when traces are recalled
using flashback.
d. Cumulative Measurements. Any measurements that are on when the Lab Notebook entry is created are not saved
individually in the database, other than being embedded in the hardcopy image. This means that when flashback is used,
the measurements will be recomputed using the waveform data that was recalled. Normally this will not pose a problem, but
if cumulative measurements were on, which accumulated data from multiple acquired waveforms, they will loose their
history and show instead only the results from the stored waveforms.
Creating a Report
Once the notebook entry is created, you can easily generate a hardcopy report for e-mailing or
printing.
Previewing a Report
Before creating a report, you can preview it by simply touching the View button
exit the preview, touch the Close button at the right of the dialog.
. To
Locating a Notebook Entry
A search filter is provided to help you locate the notebook entry you want to make a report of. You
can search by date or keyword.
342
WM-OM-E Rev I
X-Stream Operator’s Manual
1. Touch the Filter button
search dialog box opens.
.A
2. Touch inside the Day, Month, and Year
fields and enter a date. Or touch inside
the Keyword field and enter a keyword
or phrase.
3. Touch Find Now. Only the entries fitting
the date or keyword criteria will now
appear in the list box.
Creating the Report
1. Select a notebook entry in the list box
.
WM-OM-E Rev I
343
2. Touch inside the Format field and select a report format from the pop-up menu
3. Touch the Create Report button.
4. A dialog box opens in which to name the report and select a folder to contain the report. Touch
inside the File name field and enter a name using the pop-up keyboard.
5. If you want to e-mail or print the data to a network printer, touch More Actions, then the Print
or E-Mail button. If you select Print, a Windows dialog box will open for you to select a printer
and set options. If you select E-Mail, the report will be sent immediately to the e-mail address
configured in Utilities Preferences.
Formatting the Report
LeCroy provides a default report format (template); however, you can use your own format,
including company logo.
1. Touch the Advanced tab.
2. Touch inside the Directory field and navigate to a folder to contain the reports.
3. Touch the Browse button next to Template to navigate to an existing report format that you
want to use. Or touch inside the Template field and enter the name and path to the template,
using the pop-up keyboard. Otherwise, touch the Use Default checkbox to use LeCroy's
format.
4. To use a logo other that the one provided, which indicates the scope that produced the report,
browse to the bit map file or touch inside the Logo field and enter the name and path to the file,
using the pop-up keyboard. Otherwise, touch the Use Default checkbox to use LeCroy's logo:
344
WM-OM-E Rev I
X-Stream Operator’s Manual
Note: If you elect to use your own logo bit map, do not use a bit map larger than 180 pixels (height) x 100 pixels (width).
Managing Notebook Entry Data
Adding Annotations
You can add annotations to your notebook entry at any time.
1. Touch the "LabNotebook" tab.
2. Touch the notebook entry you want to annotate in the scroll list box. A new tab will appear
bearing the name of the selected notebook entry.
3. Touch the new tab, then the Scribble button
. The notebook entry will appear again
with the drawing toolbar, described in Creating a Notebook Entry.
Deleting Notebook Entries
1. Touch the "LabNotebook" tab.
2. Touch the Delete All button
to clear the database, or Select a notebook entry in
the list box, then touch the Delete button
to discard just that one entry.
Saving Notebook Entries to a Folder
You can save notebook entries to a folder other than the default.
1. Touch the tab bearing the name of the notebook entry.
. A navigation window opens, which provides the
2. Touch the Save Data to button
opportunity also to open Windows Explorer to navigate to the folder.
3. Touch the Zip checkbox
if you want to compress the data before archiving.
Managing the Database
You can begin a new database for your notebook entries at any time, back up the current one, or
compress the data.
WM-OM-E Rev I
345
To Select a Database for Backup or Compression
1. Touch the Advanced tab.
2. Touch the Browse button. A navigation window opens. Navigate to the database you want to
work on
Touch Compact to reduce the size of a database. This function "defragments" the
notebook after a large amount of entries have been deleted.
Insert a memory stick into a USB port, then touch Backup to send the database to the
external media:
To Start a New Database
Touch the Start New button. The name of the notebook database will be incremented by 1:
346
WM-OM-E Rev I
X-Stream Operator’s Manual
DDA
DDA Front Panel Controls
The front panel of the DDA is similar to that of other X-Stream scopes except for the substitution of
the Drive Analysis button
for the Default Setup button.
When you press the Drive Analysis button, you gain access to the Drive Analysis setup dialogs:
To recall the default setup on a DDA, press the Save/Recall front panel button, then select the
"Recall Setup" tab and touch the Recall Default Setup button.
Note: You can also touch File in the menu bar, then Recall Setup... in the drop-down menu.
DDA Specifications
Additional DDA Triggers
Sector Pulse: Triggers on the nth sector pulse (1 to 50) after index. Index and sector pulse polarity
and sector pulse number are selectable.
Servo Gate: Triggers on the nth servo gate after index and every mth thereafter. Index and servo
gate pulse polarity are selectable.
PES Trigger: Triggers on Position Error Signal (PES) exceeding an adjustable voltage window.
Servo gate can be selected as qualifier.
Read Gate Trigger: Triggers on any read gate longer than an adjustable Sector ID field length (100
ns to 50 µs).
Disk Drive Measurement Package (DDM2)
This package provides disk drive parameter measurements and related mathematical functions for
performing disk drive WaveShape Analysis.
WM-OM-E Rev I
347
•
Disk Drive Parameters:
amplitude symmetry
local time over threshold
auto correlation s/n
local time trough-peak
local base
local time under threshold
local baseline separation
narrow band phase
local maximum
narrow band power
local minimum
non-linear transition shift
local number
overwrite
local peak-peak
pulse width 50
local time between events
pulse width 50-
local time between peaks
pulse width 50+
local time between troughs
resolution
local time at minimum
track average amplitude
local time at maximum
track average amplitude-
local time peak-trough
track average amplitude+
•
Correlation function
•
Trend (datalog) of up to one million events
•
Histograms expanded with 19 histogram parameters and up to 2 billion events
Automated DDA Measurements
ACSN
local time under threshold
local base
msnr
local baseline separation
m_to_r
local maximum
NLTS
local minimum
narrow band phase
local number
narrow band power
local peak-peak
overwrite
local time between events
pulse width 50
local time between peaks
pulse width 50-
local time between troughs
pulse width 50+
local time at minimum
resolution
348
WM-OM-E Rev I
X-Stream Operator’s Manual
local time at maximum
rsnr
local time peak-trough
track average amplitude
local time over threshold
track average amplitude-
local time trough-peak
track average amplitude+
Advanced DDA Analysis
•
Head Filter/Equalizer Emulation
•
Channel Emulation
•
SAM Histograms
•
Plot of SAM Values
•
PES Runout Analysis
•
Analog Compare
•
Correlation
•
Trend
•
Histogram
Drive Analysis Overview
Obstacles that Can Be Overcome Using the DDA’s Channel Analysis
Disk Drive engineers who are analyzing channels to determine where and why data errors occur
face important obstacles. But the DDA’s Channel Analysis feature can be used to overcome these
obstacles.
Lack of Synchronization
The first obstacle is the lack of integration or synchronization between the computers used to
identify and locate data errors, and the instruments that analyze the channel signals. It is, therefore,
difficult to capture the signal that may be responsible for an error at the same point in time at which
the error occurs. If an error is repetitive, its signal can be captured and viewed. But if the error is
intermittent, capturing it at the correct time may be impossible.
Unknown Sectors
Another obstacle is that the data written to a particular sector may not be known. And because no
reference is available, the exact location of an error in a particular sector cannot be determined. In
order to have a known data set, data may subsequently be written to the sector concerned.
Nevertheless, there is no guarantee that this will recreate the error. For many, writing to a sector
with errors is the last resort.
Problematic PRML
Another problem is the difficulty of analyzing partial response maximum likelihood (PRML) head
signal quality and identifying both the problem locations and the margin available before errors
WM-OM-E Rev I
349
occur. Head signals for PRML channels have complex waveshapes, which are very difficult or even
impossible to analyze by visual inspection. Analysis of these signals with an oscilloscope is often
limited to looking for gross abnormalities such as significant thermal asperities or dropouts of
sufficient duration. Furthermore, because of the sophistication of PRML signal processing, even
some visible anomalies may not necessarily cause an error.
Time and Effort
Lastly, data in the sectors is complex and lengthy, and it can take significant time and effort to scroll
through and visually inspect signal locations. The problem is of data presented in a time-linear
fashion, rather than in the order of signal areas most deficient in PRML channel related signal
integrity.
In an integrated environment, the Channel Analysis feature analyzes the head signal. Designed to
overcome the obstacles just described, it combines powerful analytical tools with the ability to
capture and analyze the head signal in a synchronized way.
What Channel Analysis Provides
The DDA’s Channel Analysis feature provides insight into channel data quality and errors, even
while data is being processed through the channel. It can also do the following:
•
Filter and display the head signal with automatic or selectable settings for -3dB cutoff
and boost
•
Select head signal sections to be viewed by byte number
•
Provide a display of PRML target levels annotated on the head signal trace to provide
an intuitive visual indication of head signal quality
•
Identify head signal locations of the poorest quality from a PRML standpoint, quantify
the quality of the signal at these locations, and display in order of poorest quality the
head signal location and the byte number of each error
•
Identify areas where two head signal differences are greatest and provide a
benchmark for the difference and the byte locations where these occur
The Channel Analysis feature can be operated in either of these basic modes:
•
Channel Emulation
•
Analog Compare
Because each requires a similar setup, both share the same Channel Setup menu system, which
lets you switch between modes without the need to redefine setup details.
Channel Emulation
Often when examining a partial response maximum likelihood (PRML) data signal, it may be
desirable to view those signal locations where the quality is poorest and the signal is likely to be the
most problematic for a PRML channel.
Channel Emulation enables analysis of PRML head signal quality from the point of view of the
PRML channel. This is made possible by the emulation of PRML channel processing by means of
350
WM-OM-E Rev I
X-Stream Operator’s Manual
signal equalization, automatic gain control (AGC), phase lock loop (PLL), sampling, and Viterbi
detection.
For each PRML sample, a quality sequenced amplitude margin (SAM) benchmark is determined.
The lower the value of SAM the greater the difficulty for the drive channel to produce the right data
value for that sample, and the less margin there will be. A SAM value of less than zero indicates
that an incorrect data value will be selected at that sample.
PRML signals characteristically have a set of target-level values that the signal samples should
meet at the sampling times. For example, for a PR4 signal, the targets are 1 0 -1. In order to
achieve these desired levels, the DDA’s channel emulation equalizes the head signal, either
automatically or using selected values for -3 dB cutoff and boost. The equalized head signal is then
displayed. This lets you examine the head signal after it is processed, when it will have the
characteristic PRML waveshape.
The distance of the waveform samples from the PRML target values is a first-order indication of the
quality of a PRML signal. The channel emulation annotates the head signal after equalization with
the target values. This makes visual interpretation of the quality of the head signal possible and
intuitive. As a result, you can visually inspect the head signal to an extent beyond the more obvious
indications of problems such as thermal asperities and dropouts.
In addition, several powerful ways are available for selecting how the section of the equalized,
annotated head signal will be viewed:
•
You can scroll through the head signal in the traditional time sequential mode using the
Auto Scroll feature, which provides "hands free" scrolling at a rate and in the direction
that you specify.
•
You can select which part of the head signal is to be displayed by byte number. This is
particularly useful if a data error is known to exist at a particular byte location.
•
You can review the head signal in order of poorest SAM value. This capability is
particularly practical because the areas of poorest quality are generally of greatest
interest.
The ways in which Channel Emulation can be operated are with or without a reference signal, and
Stop on SAM (on/off).
With or Without Reference
Using a reference head signal, where available, provides two major benefits. First, the head signal
under analysis can be viewed with a head signal that has a reference for improved interpretation of
waveform misshapes. The DDA will equalize both reference and head signals. It will also auto-align
the two signals when selecting the head signal to be viewed by SAM --- even if they were captured
at different spindle speeds (up to 1%).
An additional benefit is that the SAM calculation can then assume values less than zero and
indicate a data error likely at that point. Without a reference signal, it would be impossible to
determine whether an error occurs for a particular sample, only the confidence (SAM) of the Viterbi
detector in selecting between a data ‘1’ or data ‘0’ for a particular sample. In this case, the minimum
confidence level possible is zero SAM, indicating no confidence in making a selection. The correct
data can be specified with a reference, which allows SAM values of less than zero to be detected
WM-OM-E Rev I
351
when the signal quality is so poor that an incorrect data value would be selected by the DDA's
Viterbi detector.
Stop On SAM
The second selection mode of operation is Stop on SAM. When this mode is enabled, the DDA is
placed in what is essentially a test mode for PRML signal quality based on SAM. When in Normal
acquisition mode, the DDA will continuously acquire and analyze head signals until it finds a PRML
sample value with a SAM value below a user-specified level. When this occurs, acquisition will be
stopped, and the user can directly view the locations below the selected SAM threshold. This mode
of operation is particularly useful for capturing intermittent errors.
Analog Compare
Often the head signal locations requiring examination are a header or other non-PRML data section.
You may wish to compare these signal sections to a reference signal in order to obtain visual clues
to possible problems. However, several issues may have to be addressed before this can be done.
The reference and head signals might differ in time due to spindle speed variations. This could
make alignment and comparison of the two signals difficult.
Another issue is that differences may be so subtle that they are not very apparent --- especially so
if the signals being compared are lengthy.
A third issue is that the problem may be intermittent.
What is generally required for addressing all three issues is an automatic comparison method that
adjusts for spindle speed variations and identifies where the two signal differences are the greatest.
In the case of intermittent problems, comparisons should be made continuously until a difference
greater than a selected threshold is seen. This is just what the Analog Compare feature provides.
With Analog Compare, you select a head signal to act as the reference, and it gets stored in
memory. The maximum allowable difference between the two signals is then selected. Analog
Compare automatically aligns the two signals and identifies where a mismatch occurs. It also
counts each mismatch, storing its byte location for further review. Up to 100 mismatches can be
identified and stored in largest-to-smallest order.
As a general-purpose test method, Analog Compare can be applied to finding problems in
practically any signal, including other head signals.
General Steps of Analog Compare
1. Tell the DDA the signals you are providing: Identify in the Channel Setup the signals
that are being provided and their source --- the particular input channel or memory. Also
identify the section of the head signal you want analyzed.
2. Set up the channel characteristics: Each of the Channel Analysis methods has a
required set of head signal characteristics that need to be provided in order to perform the
necessary analysis. These may include bit cell time, code rate, PRML type, and other
characteristics.
3. Select a channel analysis method: Specific configuration requirements differ depending
on the method used. See “Setting up for Using Drive Channel Analysis” in the Disk Drive
352
WM-OM-E Rev I
X-Stream Operator’s Manual
Analyzer Reference Manual for more information.
4. Turn on and configure the method selected: Once a channel analysis method is
selected, it needs to be configured and turned on.
5. Review the problems the DDA identifies: Review the head signal areas that the DDA
identifies as having the poorest quality or differences from a reference. If the method
selected is Channel Emulation with Stop on, SAM on, or Analog Compare, head signal
sections that exceed a user-specified threshold will be displayed. If no sections exceed the
selected threshold, it may be desirable to adjust the threshold until violations are identified.
Head Signal Filtering
When you are visually analyzing or measuring a servo head signal, it is usually desirable to first
filter the head signal to remove noise. In addition, if boost is provided in the servo system, adding
the corresponding boost to the displayed or measured head signal may also be beneficial. This
allows analysis of the head signal as the servo processing system sees it.
The ability to set values for the -3 dB cutoff, boost and group delay is provided by this Servo
Analysis feature. In addition, the filter provided can be easily set up to view or measure any head
signal.
Analog Compare
When you are attempting to locate a problem in a wedge signal, for example, the same
complications are encountered as with Channel Analysis --- with similar solutions.
Noise Analysis
Disk noise parameters enable parameter measurements of media signal-to-noise (msnr), residual
(electronics) signal-to-noise (rsnr), and the ratio of media to residual signal-to-noise (m_to_r). The
calculation of all three parameters is based on the distribution of the averaged Viterbi input
samples.
•
msnr can be applied to any single-frequency, sector-based data pattern. The
single-frequency data will be sampled at the peaks (maxima), zero crossings, and
troughs (minima). Any deviations from the ideal sample points will be a result of noise.
By performing multiple reads, random noise can be averaged away. With this
measurement, the repeating media noise level can be derived by msnr.
•
rsnr can be applied to any single-frequency, sector-based data pattern. The
single-frequency data will be sampled at the peaks (maxima), zero-crossings, and
troughs (minima). Any deviations from the ideal sample points will be a result of noise.
By performing multiple reads, random noise can be quantified. With this measurement,
the non-repeating residual (electronics) noise level can be derived by rsnr.
•
m_to_r can be applied to any single-frequency, sector-based data pattern. The msnr is
compared with the rsnr. The resulting ratio indicates whether the signal is dominated
by media noise if it is greater than 1.00, or dominated by residual (electronics) noise if
less than 1.00.
WM-OM-E Rev I
353
Measure’s Drive Parameters
The buttons accessed via the "Measure" tab allow quick and convenient setup of the most common
sets of measurements made on a head signal. These include:
•
Track Average Amplitude (TAA), PW50
•
Amplitude Asymmetry, PW50+, PW50-, Baseline Separation, and TAA
•
Auto-Correlation Signal-to-Noise (ACSN)
•
Non-Linear Transition Shift (NLTS)
•
Jitter (period at level)
Setting Up Channel Emulation
Drive Analysis Setup
1. Press the DDA's front panel Drive Analysis button
appear.
. The disk drive dialogs
2. Touch the Drive Analysis tab
.
3. Touch the Channel Emulation button
checkboxes, buttons, and data entry fields appear.
. The Channel Emulation setup
4. Touch inside the Head Signal field and select a signal source from the pop-up menu. The
choices comprise channel inputs C1-C4, math traces F1-F8, memories M1-M4, or
Reference. See Channel Emulation with Reference and Channel Emulation without
354
WM-OM-E Rev I
X-Stream Operator’s Manual
Reference for guidelines on using a Reference.
5. Touch the Trace On checkbox to turn the Head Signal on.
6. Touch inside the Read Gate field and select a source from the pop-up menu. The choices
include Ref and none. Read Gate If the Read Gate signal is connected to a DDA-5005A
channel and specified, it will be used to determine the regions of the signal to be analyzed.
Since the VCO Synch field is required for Channel Emulation with Reference and is
normally present in the head signal in every block just after Read Gate goes true, it is
recommended that Read Gate be used. If Read Gate is not present, the entire waveform
will be used unless the Analyze Region cursors are enabled.
7. If for Read Gate you selected other than none, Touch inside the Gate Polarity field and
select positive or negative polarity.
8. Touch inside the Compare to Reference checkbox to enable comparison of the Head
Signal to the Reference. Then touch the Store Reference button.
9. Touch the Stop on SAM checkbox if you want to stop the acquisition when the signal falls
below a user-defined SAM value. Stop on SAM When this mode is enabled, the
DDA-5005A is placed in what is essentially a test mode for PRML signal quality based on
SAM. When in Normal acquisition mode, the DDA-5005A will continuously acquire and
analyze head signals until it finds a PRML sample value with a SAM value below a
user-specified level. When this occurs, acquisition will be stopped, and you can directly
view the locations below the selected SAM threshold. This mode of operation is particularly
useful for capturing intermittent errors.
10. Touch inside the SAM Threshold data entry field and enter a value from 0 to 2 , using the
pop-up numeric keypad. See SAM in "PRML Channel Emulation" then touch Back
to complete this setup.
11. Touch the Show ML Markers checkbox to enable the markers. ML Markers The ML
Markers indicate the location of the ideal PRML sample values based on the DDA-5005A’s
channel emulation.
12. Touch the Show Level Markers checkbox to enable the markers. Level Markers The Level
Markers indicate the vertical position of the PRML levels based on the amplitude of the
acquired PRML signal. The Level Markers indicate the vertical position of the PRML levels
based on the amplitude of the acquired PRML signal. They reflect the levels at the center of
the display.
13. Touch the Specify Region checkbox to specify a start and end time, if desired. This may
be necessary if you are not using a Read Gate. If you are not using Read Gate, the
Analytical Region must start with a preamble for VCO synchronization. Touch inside the
Start and End data entry fields and enter starting and ending time values from -1.0 ks to
+1.0 ks, using the pop-up numeric keypad.
14. To jump to a position in the head signal, touch inside the "Position" Segment field and
enter a value from 1 to 999, using the pop-up numeric keypad. Then touch inside the Byte
field and enter a value from 50 to 50,000.
WM-OM-E Rev I
355
15. To jump to a "worst SAM" area, after channel emulation, touch inside the Worst Error #
field and enter a value from 1 to 100, using the pop-up numeric keypad.
Channel Setup
1. Touch the Channel Setup tab:
.
The Channel Setup buttons and data entry fields appear.
2. Touch inside the Signal Type field and make a selection from the pop-up menu:
.
356
WM-OM-E Rev I
X-Stream Operator’s Manual
3. Touch inside the Code Rate field and make a selection from the pop-up menu:
.
If you select Custom, also touch inside the Custom m/n data entry field
and enter new m and n values, using the pop-up keyboard. See PRML Encoding in "PRML
Channel Emulation" then touch Back
to complete this setup.
4. Touch inside the Adjacent Transitions (d) field and make a selection from the pop-up
menu:
.
In general, PR4 and EPR4 use d=0; 2/3(1,7) encoded E2PR4 uses d=1.
5. Touch inside the Run Length Limit (k) field and enter a value from 0 to 99 using the
pop-up numeric keypad.
6. Touch inside the Bit Cell Time field and enter a value from 1.00 ns to 1.00 µs using the
pop-up numeric keypad. Then press the Measure Bit Cell Time button. See Principle of
Equalization in "PRML Channel Emulation" then touch Back
to complete this setup.
7. Touch inside the VCO synch | data field and enter a value from 1 to 32 using the pop-up
numeric keypad.
WM-OM-E Rev I
357
8. Touch inside the Ignore Last Samples field and enter a value from 0 to 999.
9. Touch the Filter head signal checkbox to enable filtering of the head signal; then touch the
Train Filter button to automatically set up equalization on the currently acquired head
signal. See Train Filter in "PRML Channel Emulation" then touch Back
to complete
this setup. If you do not automatically train the filter, you need to perform steps 10 and 11 to
manually set up the equalization filter.
10. Touch inside the 3 dB Frequency field and enter a value from 1.0 MHz to 800 MHz using
the pop-up numeric keypad. See 3 dB Frequency in "PRML Channel Emulation" then touch
Back
to complete this setup.
11. Touch inside the Boost field and enter a value from 0 to 13 dB using the pop-up numeric
keypad. See Boost at fc in "PRML Channel Emulation" then touch Back
this setup.
to complete
12. Touch inside the Group Delay field and enter a value from 30.0% to +30.0% using the
pop-up numeric keypad. See Group Delay in "PRML Channel Emulation." This parameter
is not set by the "Train Filter" function.
Setting Up Analog Compare
Drive Analysis Setup
1. Press the DDA's front panel Drive Analysis button
appear.
. The disk drive dialogs
2. Touch the Drive Analysis tab:
358
WM-OM-E Rev I
X-Stream Operator’s Manual
3. Touch the Analog Compare button
buttons, and data entry fields appear.
. The Analog Compare setup checkbox,
4. Touch inside the Head Signal field and select a signal source from the pop-up menu. The
choices comprise channel inputs C1-C4, math traces F1-F8, memories M1-M4, or
Reference. See Using Analog Compare for guidelines on using a Reference.
5. Touch the Trace On checkbox to turn the Head Signal on.
6. Touch inside the Read Gate field and select a source from the pop-up menu. The choices
include Ref and none. Read Gate If the Read Gate signal is connected to a DDA-5005A
channel and specified, it will be used to determine the regions of the signal to be analyzed.
If Read Gate is not present, the entire waveform will be used unless the Analyze Region
cursors are enabled.
7. If for Read Gate you selected other than none, Touch inside the Gate Polarity field and
select positive or negative polarity.
8. Touch the Store Head Reference button.
9. Touch the Specify Region checkbox to specify a start and end time, if desired. (This may
be necessary if you are not using Read Gate. If you are not using Read Gate, the Analysis
Region must start with a preamble for VCO synchronization.) Then touch inside the Start
and End data entry fields and enter starting and ending time values from -1.0 ks to +1.0 ks,
using the pop-up numeric keypad.
10. To jump to a position in the head signal, touch inside the "Position" Segment field and
enter a value from 1 to 999, using the pop-up numeric keypad. Then touch inside the Byte
field and enter a value from 50 to 50,000.
11. Touch inside the Worst Error # field and enter a value from 1 to 100, using the pop-up
numeric keypad.
12. Touch inside the Analog Threshold field and enter a value from 0 mV to 1 V.
Channel Setup
Channel Setup is required for Analog Compare, which is the same as for Channel Emulation.
Setting Up Noise Analysis
1. Press the DDA's front panel Drive Analysis button
appear.
. The disk drive dialogs
2. Touch the Drive Analysis tab:
WM-OM-E Rev I
359
3. Touch the Noise Analysis button. The Noise Analysis setup checkbox, buttons, and data
entry field appear.
4. Touch inside the Head Signal field and select a signal source from the pop-up menu. The
choices comprise channel inputs C1-C4, math traces F1-F8, memories M1-M4, or
Reference.
5. Touch the Trace On checkbox to turn the Head Signal on.
6. Touch inside the Read Gate field and select a source from the pop-up menu. The choices
include Ref and none. Read Gate If the Read Gate signal is connected to a DDA-5005A
channel and specified, it will be used to determine the regions of the signal to be analyzed.
Since the VCO Synch field is required for Noise Analysis with Reference and is normally
present in the head signal in every block just after Read Gate goes true, it is recommended
that Read Gate be used. If Read Gate is not present, the entire waveform will be used
unless the Analyze Region cursors are enabled.
7. If for Read Gate you selected other than none, Touch inside the Gate Polarity field and
select positive or negative polarity.
8. Touch the Setup for Single Frequency button. This action automatically selects
parameters msnr, rsnr, and m_to_r as Source1 in "Measure" dialog positions P1 to P3,
respectively. ParamPassThru is the Measure selection made for each, which means that
the output is the same as the input.
9. Touch the Avg. Samples checkbox to enable averaging.
10. Touch inside the Max Averages data entry field and enter a value from 1 to 32,000 using
the pop-up numeric keypad. Then touch the Reset Average button to clear the previous
average.
360
WM-OM-E Rev I
X-Stream Operator’s Manual
Setting Up Disk Triggers
Read Gate
Read Gate triggers on a pulse of a specified minimum width on the Read Gate source. To set it up,
proceed as follows:
1. Press the DDA's front panel Drive Analysis button
appear.
. The disk drive dialogs
2. Touch the Disk Triggers tab.
3. In the "Disk Trigger Types" menu
, touch Read Gate. The
Read Gate data entry fields appear. See Read Gate in "Channel Analysis Concepts" then
touch Back
to complete this setup
4. Touch inside the Minimum Width data entry field and enter a value from 100 ns to 100 µs.
5. Touch inside the Read Gate Source field and select an input channel or external source
from the pop-up menu.
6. Touch inside the Read Gate Polarity field and select positive or negative polarity from the
pop-up menu.
7. Touch inside the Read Gate Level field and enter a value, using the pop-up numeric
keypad.
Sector Pulse
Sector Pulse triggers on the specified (nth) sector start pulse after the Index mark. To set it up,
proceed as follows:
1. Press the DDA's front panel Drive Analysis button
appear.
. The disk drive dialogs
2. Touch the Disk Triggers tab.
3. In the "Disk Trigger Types" menu, touch Sector Pulse. The Sector Pulse data entry fields
appear. See Sector Pulse in "Setting Up to Use Drive Channel Analysis then touch Back
WM-OM-E Rev I
361
to complete this setup.
4. Touch inside the Trigger On Sector x after Index data entry field and enter a value from 0
to 999 using the pop-up numeric keypad.
5. Touch inside the Sector Pulse Source field and select an input channel or external source
from the pop-up menu.
6. Touch inside the Sector Pulse Polarity field and select positive or negative polarity from
the pop-up menu.
7. Touch inside the Sector Pulse Level field and enter a value from 250 mV to 250 mV using
the pop-up numeric keypad.
8. Touch inside the Index Source field and select an input channel or external source from
the pop-up menu.
9. Touch inside the Index Level field and enter a value from 250 mV to 250 mV using the
pop-up numeric keypad.
Servo Gate
Servo Gate triggers on all or selected Servo Gate pulses starting after the Index mark. To set it up,
proceed as follows:
1. Press the DDA's front panel Drive Analysis button
appear.
. The disk drive dialogs
2. Touch the Disk Triggers tab.
3. In the "Disk Trigger Types" menu, touch Servo Gate. The Servo Gate data entry fields
appear.
4. Touch inside the After index wait x servo gates field and enter a value from 0 to 999
using the pop-up numeric keypad.
5. Touch inside the then skip x gates between triggers field and enter a value from 0 to 999
using the pop-up numeric keypad.
6. Touch inside the Servo Gate Source field and select an input channel or external source
from the pop-up menu.
7. Touch inside the Servo Gate Polarity field and select positive or negative polarity from the
pop-up menu.
8. Touch inside the Servo Gate Level field and enter a value from 250 mV to 250 mV using
the pop-up numeric keypad.
9. Touch inside the Index Source field and select an input channel or external source from
the pop-up menu.
362
WM-OM-E Rev I
X-Stream Operator’s Manual
10. Touch inside the Index Level field and enter a value from 250 mV to 250 mV using the
pop-up numeric keypad.
Setting Up Zoom
You can zoom on a particular segment and byte of your signal as follows.
1. Press the DDA's front panel Drive Analysis button:
.
The disk drive dialogs appear.
2. Touch the Zoom tab.
3. Touch inside the Position Segment data entry field and enter a value from 1 to 999 using
the pop-up numeric keypad.
4. Touch inside the Position Byte field and enter a value from 50 to 50,000 using the pop-up
numeric keypad.
5. If you want to increase or decrease your horizontal or vertical zoom in small increments,
touch the Var. checkbox in the right-hand dialog to enable variable zooming. Now with
each touch of the zoom control buttons
, the degree of magnification will
change by a small increment. To zoom in or out in large standard increments with each
touch of the zoom control buttons, leave the Var. checkbox unchecked. To set exact
horizontal or vertical zoom factors, touch inside the Horizontal Scale/div data entry field
and enter a time-per-div value, using the pop-up numeric keypad. Then touch inside the
Vertical Scale/div field and enter a voltage value.
6. To reset the zoom to x1 magnification, touch Reset Zoom in the dialog or press the front
panel zoom button:
.
WM-OM-E Rev I
363
DDA REFERENCE INFORMATION
Channel Analysis Concepts
The purpose of Channel Analysis is to find signal quality problems in the head signal. Thus both
methods used by the DDA --- Channel Emulation and Analog Compare --- require that you first
specify the DDA channel or memory on which the head signal is to be carried.
The instrument utilizes the head signal and, optionally, the Read Gate and the Analyze Region
cursors to determine which part of the head signal will be analyzed. What follows is an explanation
of how the instrument does this and the manner in which it processes the head signal.
The following figure shows the fields of the head signal and their relationship to Read Gate.
Head Signal Fields and Read Gate
In a normally operating disk drive, every time Read Gate goes true (at the beginning of every
segment to be read) there must be a repetitive signal called the VCO Synch (voltage-controlled
oscillator). It is needed to adjust the phase of the PLL (phase locked loop), which generates the
sampling clock, and to adjust the AGC (automatic gain control).
The DDA will try to identify the VCO Synch signal in a similar fashion in order to perform channel
emulation. In order to identify VCO Synch, you will need to provide a Read Gate signal or to set the
Analyze Region cursors (see Selecting the Waveform Section to be Analyzed). After the DDA
analyzes the VCO Synch signal, it is ready to analyze the data field for problems. Since the data
field generally does not start immediately after the end of the VCO Synch field, the DDA needs to
know where the data field starts. You must specify the number of bytes between the VCO Synch
field and the data field. The DDA can then determine the location of the first byte of data.
If the channel analysis method selected is Channel Emulation, the DDA will perform PRML
channel emulation to determine the location of problems in the data field. Often, there is a delay
between the end of valid data and the disabling of the Read Gate. It is generally not meaningful to
analyze this area of a sector for problems. In order to avoid analyzing this area, you can specify the
number of PRML samples between the end of valid data and Read Gate being disabled in the
Ignore Last Samples data entry field in the "Channel Setup" dialog.
Using the DDA's Equalization Filter
Disk drives generally have filters to remove noise and to shape the head signal. Without these
filters, data would not be properly recovered. The DDA provides a similar filter capability. The
equalization filter available in the instrument’s channel emulation can be used with all the channel
analysis methods to clean up and shape the signal, much like the channel chip will do.
It is recommended that unless the head signal has been equalized before being acquired by the
DDA, the filter should be applied. Otherwise false problems may be reported. If you have access to
the equalized signal from the drive, this signal can be provided to the DDA. The filter should not be
used in this case. The following figure shows the same signal before and after using the DDA’s
filter.
Before and after filtering
As you can see, it would be very difficult to perform meaningful analysis of the "before" picture,
because of noise. Note that Maximum Likelihood (ML) Markers ("+" signs) and Level Markers
364
WM-OM-E Rev I
X-Stream Operator’s Manual
(horizontal lines) are displayed in the "after" picture. The ML Markers indicate the location of the
ideal PRML sample values based on the DDA’s channel emulation. The Level Markers indicate the
vertical position of the PRML levels based on the amplitude of the acquired PRML signal.
Selecting the Waveform Section to Be Analyzed
For the Analog Compare and Channel Emulation channel analysis methods, you can specify
selective areas of the head signal for analysis by using the Analyze Region cursors or the drive’s
Read Gate signal, or both.
As discussed above, it is important for the DDA to be able to analyze the VCO Synch signal at the
beginning of the region it is analyzing. If Read Gate is used to determine which head signal sections
to analyze, this will not be a problem, since the DDA will use Read Gate to identify the location of
VCO Synch. If Read Gate is not used, it is important, by means of the Analyze Region cursors, that
the beginning of the head signal section analyzed be very near the beginning of VCO Synch.
The following figures show the areas of the waveform to be analyzed, with the different
combinations of the Analyze Region cursors or Read Gate, or both, enabled. The Analyze Region
cursors, if enabled, generally specify the outer-most boundaries of the data to be analyzed. They
are particularly useful if Read Gate is not available or if only a subset of several Read Gate true
sections captured is to be analyzed --- for example, a single sector within several captured, or
excluding the ID field. Within the area designated by the markers, if Read Gate is specified, only the
regions of the Head Signal during which Read Gate is true are analyzed (as shown in Case 1) while
all others are ignored.
Case 1: Only Read Gate True regions are analyzed
Similarly, if Analyze Region is disabled and Read Gate enabled, the area of the Head Signal during
which Read Gate is true is analyzed, as shown in sections A, B, C, D, and E in Case 2
Case 2: Head Signal Read Gate True regions analyzed
WM-OM-E Rev I
365
If Analyze Region is enabled and Read Gate is not available, only the area of the Head Signal
within the region is analyzed, as shown in Case 3.
Case 3: Only the area within the Region is analyzed
If neither the markers nor Read Gate are enabled, the entire Head Signal is analyzed (Case 4).
366
WM-OM-E Rev I
X-Stream Operator’s Manual
Case 4: The entire head signal is analyzed
DDA Markers
If Read Clock is acquired by the DDA, the "sample time" markers can be drawn. Because the phase
relation of RCLK to the head signal is not known, it is adjustable. It is worth noting here that the ML
markers are at positions determined by the instrument's channel emulation; the sample time
markers are at positions determined by the channel's sample clock signal with ML markers ("+"
signs) and level markers (horizontal lines).
Setting Up to Use Drive Channel Analysis
There are several basic considerations when you are preparing to use Drive Channel Analysis.
Which signals are to be provided to the DDA? What waveform section or sections will be analyzed?
What will be used as the reference waveform? What trigger and time/div settings should be used?
Which Signals to Provide
The following is an overview of the signals that can be used by the DDA.
•
Head Signal: The drive head signal is the only signal the DDA requires. The drive head
signal can either be the signal after the pre-amplifier, or the one after the drive filter if
available.
•
Read Gate: Read Gate is "optional" for all error find methods; however, it is strongly
recommended that you use Read Gate.
Choosing the Waveform Section to Be Analyzed
Before using Drive Channel Analysis, you should determine which part of the head signal will be
analyzed.
The options you have are to analyze:
•
Part of a single Read Gate cycle
•
A single Read Gate cycle
•
Multiple Read Gate cycles.
WM-OM-E Rev I
367
There are additional considerations for each of these choices.
If you choose to analyze a part of a single Read Gate cycle, it is important that it include the VCO
Synch signal. Because it will be difficult to set up a reference signal if it is less than a single Read
Gate cycle, it is recommended that this not be done with either the Analog Compare or Channel
Emulation methods.
If you want to analyze a single Read Gate cycle, the easiest approach is to use the Read Gate
signal and, if necessary, the Analyze Region cursors, to determine which section is analyzed. If you
are using Channel Emulation or Analog Compare, you must make sure that the reference signal is
the same length (see the following Selecting the Reference Waveform).
If you wish to analyze multiple Read Gate cycles, the setup is the same as for a single Read Gate
cycle. The Read Gate signal and, if necessary, the Analyze Region cursors are used to determine
which sections are analyzed. If you are using Channel Emulation or Analog Compare, you need to
ensure that the reference signal is of similar makeup.
Except for Analog Compare, there are limits as to how much data the channel analysis methods
can analyze at the same time:
•
Channel Emulation without a reference saves ML sample results for up to 20,000 bits,
which are used to draw the ML sample (+) markers.
•
Channel Emulation with a reference saves up to 20,000 bits as its reference, while
also saving ML sample results; there can be up to 250 separate Read Gate true
sections in the data analyzed by Channel Emulation with reference.
•
Analog Compare can handle one block of data of any length up to the maximum that
can be acquired and stored by the DDA. It is the most computationally intensive error
find method, so its use on maximum length waveforms will not be typical. Another
indirect constraint on waveform size arises if Read Gate is used. If the source of Read
Gate is set to something other than NONE, Read Gate will break the data into multiple
blocks. In that case, there is a requirement that the start of each block, relative to the
first block in the reference and the acquisition, be the same within the DDA’s
realignment window of about 12 bit cells.
Selecting the Reference Waveform
The Analog Compare and Channel Emulation with reference signal channel analysis methods
compare the captured head signal to a stored reference head signal. For these methods, the
appropriate menus will only appear after a head signal has been selected.
The stored reference should be acquired in the same manner (same time/div, sample rate, trigger
position, etc.) and with the same timing as the acquisitions to which it is to be compared. It is not
possible to compare a reference having only one sector to every sector in an acquisition containing
many; and a split sector cannot be compared with an unsplit or differently split sector.
Generally, it is best that the reference signal be from the same drive section as the one with which
it is to be compared. This will ensure that any splits that occur are in the same location. Another
reason for selecting the same drive section is to avoid scrambler problems. If a drive uses a
scrambler, two sections with the same logic data may have different head signals. Since Channel
Emulation with reference and Analog Compare both analyze the head signal, they may see
368
WM-OM-E Rev I
X-Stream Operator’s Manual
differences between the reference and acquired signals due to the presence of the scrambler and
not because real problems exist. If a scrambler is not present, it is reasonable to use other drive
sections from the same zone as a reference.
The head signal can be stored as a reference simply in order to have a stored trace automatically
overlapped with later acquisitions. This can be done even if the selected channel analysis method
does not require a reference, or if you do not intend to use the method. This might be done just to
scroll through waveforms using Auto Scroll to see how well they match.
Changing the source of the Head Signal or Read Gate invalidates the stored reference. You must
store another valid reference for the new setup.
Time/Div Settings
The DDA allows you to keep acquiring a head signal until it finds a problem, at which point it will
stop the acquisition so that errors can be analyzed. In order for Drive Channel Analysis to operate
properly the DDA trigger must be set up so that the correct waveform section or sections are
reliably acquired. The trigger setting must be selected to obtain the desired data on the display, in
approximately the same position, in each acquisition.
In addition, the time/div must be set properly. Two factors should be taken into account when
setting this. First, the time/div should be set to a sufficient duration so that the head signal sections
that will be analyzed are captured. Second, in order for the DDA to correctly analyze a head signal
it should have at least five ADC samples per bit cell.
For drives without ID, Read Gate only goes true to read the data of interest. If you can manually
initiate a read operation of the desired data, this is easy: trigger on the leading edge of Read Gate,
and every time the data is read, the DDA will trigger. Wait for the channel analysis to be done (the
instrument rearms if no problems are found) before performing another read.
A precaution should be taken if more than a single Read Gate block of data is to be analyzed. For
this situation, if reads are being performed repeatedly it is important to ensure that the trigger mode
selected is not one that triggers solely on the occurrence of any Read Gate. Otherwise, the Read
Gate block triggered on might sometimes be the second or later Read Gate true section.
If the drive provides Sector Pulses at the beginning of each sector it is recommended that the
DDA’s Sector Pulse trigger be used to avoid this problem.
Otherwise, a SMART Trigger® can easily solve this problem, by triggering on the first (or nth) Read
Gate edge after Index.
If Read Gate is not available or its use is not desired, but looking at the head signal is, try triggering
on Index and using a trigger delay to move out to the region of interest. Use the Analyze Region
markers to delimit the area to analyze: for channel emulation methods the start marker should
always be near the beginning of the VCO Synch field. However, even 0.1% speed variance
becomes 0.8 s of jitter after 8 ms of delay. That is probably several hundred bit cells --- far more
than Analog Compare can compensate for --- which may cause the channel emulation methods to
miss the VCO Synch field entirely. Therefore this technique will not be able to look at sectors more
than 1 or 2 ms delayed from Index.
If Read Gate is unavailable and you want to look at something other than sectors of data on the
head signal, some repetitive signal such as Servo/Data can be used as Read Gate. Analog
WM-OM-E Rev I
369
Compare will have to be used then. The SMART Trigger can be set up as outlined above, except
that the bottom Qualify by: field should be set to time greater than
, and the amount of time
from index to just before the data of interest should be entered. This can be used to look at a
particular servo burst, for example.
Automatically Shown Traces
When the source of the head signal is changed from None to an input channel or memory, a trace
showing a zoom of the head signal is automatically created and displayed. If the Filter head signal
checkbox is checked, the data in the trace is filtered. All channel markers selected will appear on
this trace. All channel analysis methods analyze the (possibly filtered) data in the trace waveform
(the entire waveform, not just the part displayed). Byte offset and Worst Error # change the
horizontal position of this trace.
When Store Reference is selected, a trace showing a zoom of the stored reference is
automatically established where possible. This means that whenever Byte offset or Worst Error #
is changed, the reference will be realigned with the Head Signal at the new position. The reference
signal will also be filtered if the Filter head signal checkbox is checked.
Setting Bit Cell Time
The value in the bit cell time menu is used as a starting guess for analyzing VCO Synch. It is also
used by Byte offset and Analog Compare to determine how much time a byte occupies, and to set
the -3 dB frequency of the DDA’s equalizing filter (if enabled). It should be set correctly for the zone
being read --- it does not need to be set on each read within the same zone.
Changing the bit cell time changes the filter’s -3 dB frequency. The filter’s settings should therefore
be updated, or "trained" after the bit cell time has been changed. If the filter is on, the bit cell time
must be fairly close for Find Bit Cell Time to work.
Retraining the Filter
Training the filter adjusts the boost and the -3dB frequency to optimize the mean of the worst 100
SAM values. The training starts by setting the -3dB frequency to 0.5/bit cell time. It then alternates
optimizing the boost with optimizing -3 dB frequency. The 3 dB, boost and group delay values can
also be independently set without having the DDA automatically train.
Choosing an Analysis Method
Which method or methods should be used? Deciding this depends on the type of problem and the
information available.
By definition, a data error occurs in a drive when a bit is interpreted as a "1" when it should be a "0"
or vice-versa. In order to gain insight into the cause of the error, it is generally desirable to examine
the head signal at the location or locations where data errors occur. The DDA provides tools to help
identify the likely location of a data error. In addition, with the instrument’s channel emulation
capability you are able to gain further insight into the cause of an error or errors once location is
determined.
Before choosing a method, there are some basic questions that need to be answered:
370
WM-OM-E Rev I
X-Stream Operator’s Manual
•
Is the byte position of the error known?
•
Is a reference signal easily available?
•
Is the error repetitive or intermittent?
Recommendations on the appropriateness of each analysis method are provided below.
Analog Compare
Analog Compare is the most general of the channel analysis methods, since it can be applied to all
parts of the head signal, including VCO Synch, servo burst and data field. It is recommended for
identifying the location of errors for peak detect signals. It can also be used for PRML signals,
although Channel Emulation with a reference signal is the recommended method if a reference
signal is available. See Using Analog Compare for a full description of this method.
Channel Emulation without Reference
Since it does not require a reference, Channel Emulation without a reference signal is the easiest of
the channel analysis methods to use for PRML signals. This method performs channel emulation to
determine the locations in the head signal that gave the Viterbi detector the most trouble in its
decision as to the maximum likelihood sequence of samples. This means the state at a particular
time, in the final surviving sequence, survived by the smallest margin. (The "state" corresponds to
deciding on a "1" or "0" bit at each position.) The margin between keeping and rejecting what turned
out to be the final choice for the state at that time is called the Sequenced Amplitude Margin (SAM).
Unlike the compare methods, Channel Emulation without reference is based only on analyzing the
quality of the head signal. It is generally assumed that the quality of the head signal is strongly
correlated to the bit error or errors in nonreturn to zero (NRZ) data. Head signal sections that
produce incorrect NRZ data are much more likely to be marginal when analyzed by the Viterbi
detector. The most marginal sections are the first flagged by Channel Emulation as having the
worst SAM. See Channel Emulation Without Reference for a full description of this method.
Sections with no signal transitions are one exception to this rule. These may not be identified as
problematic by the Viterbi detector. However, if the Limit Run Length feature is enabled, sections
with no transitions will be identified as errors if they exceed the run length limit.
Because it is the easiest of all methods, Channel Emulation without reference is generally the best
to use first.
Channel Emulation with Reference
Channel Emulation with a reference is very useful if the error being looked for occurs at least fairly
frequently and a reference head signal is available. If the error is not "hard," that is, it does not occur
all the time, any acquisition may be stored as the reference; Channel Emulation with reference will
catch acquisitions for which the DDA’s channel emulation detects a different bit sequence. If the
error is hard, a separate reference must be available. To have no errors detected, the reference
must have the same bit pattern as the acquisitions with which it will be compared. This means each
sector of the reference must be either unsplit or split in the exact same place as the matching
sectors in the acquisitions with which it will be compared.
Channel Emulation without reference must assume that the final surviving sequence of bits is
correct and only points out poor quality in the head signal. But Channel Emulation with reference
WM-OM-E Rev I
371
has a reference "correct" path and will catch differences even if both the reference and the
comparison acquisition are high quality PRML signals. For Channel Emulation with a reference, the
SAM values can be negative, indicating that a different decision was made (less than 0 margin to
the "correct" state). The threshold below which an "error" is flagged is adjustable down to -1, to
permit you to flag places where the DDA’s channel emulation determines a different bit value for the
head signal as compared to the reference head signal. See Channel Emulation With Reference for
a full description of this method.
Channel Emulation without Reference
Channel Emulation without Reference finds a single trace and predicts the bits where the
Sequenced Amplitude Margin (SAM) --- the distance or margin the Viterbi detector has for making a
decision --- is poorest. It uses a full disk drive channel emulation to indicate how the signal ought to
appear when a good reference signal is not available. It measures the SAM of all the samples
(PRML clock locations).
The software emulates a PRML channel and ranks errors by SAM value. A distance or SAM value
of "0" indicates no margin for a decision and the detector’s lack of certainty as to whether the digital
bit should be "1" or "0." The positions of the 100 worst margins are identified and can be displayed
along with the SAM value of each.
Using complete disk drive channel emulation, Channel Emulation without reference predicts where
the head signal quality is the poorest in respect of a PRML channel’s ability to confidently select a
"1" or "0" value.
Channel Emulation without reference starts by finding the beginning of the sector. The algorithm
looks at the head signal beginning at the Read Gate true transition (or analyze region start if Read
Gate is not available) and tries to synchronize to the VCO Synch pattern in order to establish
sampling phase and expected sample levels. To accomplish this, it is required that VCO Synch
Pattern be set correctly, and that the "Bit Cell Time" be approximately correct. The data is then
passed through the emulated channel where it is appropriately sampled. The sampled output
enters the Viterbi detector, which chooses the "sequence" of bits (history) that is the most likely
when the new bit due to this sample is appended. The difference between the mean squared
distance (msd) of the selected sequence and the other possible sequence leading to the selected
state (SAM) is then calculated. For each sample in the Viterbi detector, Channel Emulation without
reference determines a SAM indicating the confidence it has in making a decision between the two
most likely sequences.
If Run Length Limit has a non-zero value, run length limit will also be detected and violations
reported.
If Read Gate is present, it does not necessarily go false immediately after the last byte of valid
information, usually error-correcting code (ECC). The delay is due to the propagation time through
the channel chip and any delays from the controller. Therefore, you can specify the amount of
‘garbage’ data to ignore after the end of the written data and before Read Gate goes false. Errors
detected in this area will be ignored.
When Channel Emulation without reference runs, the ML markers ("+" signs) are automatically
displayed. These show the Maximum Likelihood sample sequence that the channel emulation
chose, based on the signal and the possible sequences. They are drawn at the expected level at
372
WM-OM-E Rev I
X-Stream Operator’s Manual
the time the channel sampled the head signal. If the "+" signs are all very close to the waveform, the
signal is good. If the "+" signs are not close to the waveform, the signal may not be good. The ML
markers do not appear if more than 500 are needed on the display. If they are on but not visible,
zoom in on the head signal.
Additionally, you can turn on Level Markers, horizontal lines that show the expected levels at the
center of the screen.
The ML markers do not appear if more than 50 are needed on the display; if they are on but not
visible, they can be zoomed.
The Channel Emulation without reference method can be used either on newly acquired channel
data or data previously saved in a memory. The following information is required:
•
Head Signal: The VCO Synchronization field is needed at the beginning of the area to
be analyzed. If the VCO Synch field is not found, Channel Emulation without reference
will not be able to analyze the signal.
•
Signal Type: Specifies the type of PRML channel.
•
VCO Synch Pattern: In a normally operating disk drive, every time Read Gate goes
true (at the beginning of every segment to be read) there must be a repetitive signal
called the VCO Synch. It is required for adjustment of the phase of the PLL (phase
locked loop), which generates the sampling clock, as well as adjustment of the AGC
(automatic gain control). Most commonly, the VCO Synch is 2T (a transition every
other bit cell).
•
Bit Cell Time is used as a starting estimate of the VCO Synch signal. If the value is not
known and the VCO Synch field is at the beginning of the area to be analyzed, touching
the Measure Bit Cell Time button will determine it automatically.
•
Ignore Last <n> Samples: Specifies the amount of ‘garbage’ data to ignore after the
end of the written data and before Read Gate goes false.
•
SAM Threshold: This is the user-specified threshold used by Channel Emulation
without Reference to decide when to record an error. SAM is the difference in mean
squared distance between the samples observed from the sequence of samples
decided upon as the likely sequence and the one discarded at that decision point. See
Note 1 below.
•
Run Length Limit (k): If RLL encoding is set to zero, no check is made and Channel
Emulation without Reference only reports errors due to difficulty deciding on a
sequence of samples (small SAM). If set to a non-zero value, it specifies the number of
permitted non-transitions in a row. See Note 2 below.
•
Adjacent Transitions: Corresponds to the "d" in RLL code specified as m/n(d,k). See
Note 3 below.
Additionally, these parameters are useful (though not essential) for Channel Emulation without
reference:
•
WM-OM-E Rev I
Read Gate: If the Read Gate signal is connected to a DDA channel and specified, it will
be used to determine the regions of the signal to be analyzed. Since the VCO Synch
373
field is required for Channel Emulation, and it is normally present in the head signal in
every block just after Read Gate goes true, it is recommended that Read Gate be used.
If Read Gate is not present, the entire waveform will be used unless the Analyze
Region cursors are enabled.
•
Read Gate Polarity: Typically, Read Gate is a positive true signal. However, there are
drives that use a negative true signal for Read Gate. If Read Gate is enabled, this
setting allows you to select whether "True" is high or low.
•
Specify Region: As previously described, markers can be used to define a subset of
the head signal for analysis.
•
Filter Head Signal: If enabled, an equalization filter is applied to the head signal
before processing and display. This feature should be used if the DDA does not have
access to the drive’s equalized head signal.
Notes on Using Channel Emulation without Reference
1.
Sequenced Amplitude Margin (SAM) is used by the Viterbi detector to decide whether a bit
should be "1" or "0". As the Viterbi detector receives each sample, the detector must
choose between two possible sequences, which lead to the state it selects. The sequence
with the best fit determines which state is selected. SAM indicates how much better the
surviving sequence is than the one that is discarded from further consideration. "0" means
the Viterbi Detector has no preference at all between the sequence it chose and one it
threw away at a particular sample. The most positive value is the square of the "minimum
error distance" for the selected Signal Type, and implies excellent certainty about which
sequence to keep. SAM values are associated with the sample leaving the Viterbi
detector's trellis, that is, the sample about which the final decision is being made. The SAM
includes the effect of all previous samples in the block and of the following samples that are
already in the trellis. Near-zero SAM values are due to distortions in the shape of the head
signal. Problems causing distortions, which Channel Emulation without Reference can find,
include media defects and dropouts, asperities, noise bursts, or a bad head. (Noise bursts
are sometimes obscured by the equalization filter, and result in a distorted shape of a pulse.
To see if this is the cause of a distorted shape, look at the unfiltered waveform also.)
Without a reference Channel Emulation without Reference does not know if the decisions it
makes actually correspond to what was written, it only knows how good the head signal
looks when the disk is read. As an example, suppose a disk occasionally simply fails to
write several transitions, resulting in a flat area in the head signal. All the pulses are the
correct shape, it’s just that some aren’t there at all. This can still be caught if it causes a
Run Length Limit violation and that check was enabled, but it might not be a problem for the
Viterbi detector.
2. When checking for run length limit (RLL) violations, "k" of the RLL code "m/n(d,k)" must be
specified: "k" is the maximum number of non-transitions between transitions. When Run
Length Limit is set to a non-zero value, Channel Emulation without Reference also counts
the number of non-transitions in a row and checks against the user specified limit.
Examples: we recommend that k be set to 8 to handle 8/9(0,4,4) codes; set k to 7 for
2/3(1,7) modulation code.
3. d is the minimum number of non-transitions between transitions. When d=0, adjacent
374
WM-OM-E Rev I
X-Stream Operator’s Manual
transitions are allowed. When d=1, adjacent transitions are not permitted. For E2PR4 it can
also be set to d=2. A non-zero d eliminates several possible sequence choices (states and
transitions in the Viterbi detector). If set to 1 when it should be 0, Channel Emulation
without Reference will almost certainly detect a large number of "errors." If set to 0 when it
should be 1, it is possible that Channel Emulation without Reference will pass a few bits
that should have been flagged as errors.
Channel Emulation with Reference
Whereas Channel Emulation without Reference acquires a single trace and makes a prediction of
problems based on signal quality, when the method is used with a reference signal, it calculates the
Viterbi output of the reference, as well as that of the acquired trace, and compares the two to find
mismatches.
Channel Emulation with Reference starts by finding the beginning of the sector. The algorithm
looks at the head signal beginning at the Read Gate true transition (or analyze region start if Read
Gate is not available) and tries to synchronize to the VCO Synch pattern in order to establish
sampling phase and expected sample levels. To accomplish this, Channel Emulation with
reference requires that VCO Synch Pattern be set correctly, and that the Bit Cell Time be
approximately correct. Because the position of Read Gate relative to the head signal can jitter from
read to read, the method aligns the two bit streams it is comparing based on the end of the
repetitive VCO Synch pattern. If there is an error within the VCO Synch pattern, this will be found,
but the method may also find many other mismatches if incorrectly aligned.
The data is then passed through the emulated channel where it is appropriately sampled. The
sampled output enters the Viterbi detector, which chooses the "sequence" of bits (history) that is
the most likely when the new bit due to this sample is appended.
SAM is the margin between keeping and rejecting the correct state in the sequence, at any point.
Channel Emulation without reference essentially assumes that the output of the Viterbi detector is
"correct," and gives the margin between that and a different decision at each bit position. It must do
this because it does not have a reference. Therefore SAM results are always greater than zero from
Channel Emulation without reference --- they are the margin from the final decision to some other
decision.
Channel Emulation with reference performs channel emulation on the reference signal when it is
stored and saves the resulting bit sequence. When "Emulation" is turned on it performs channel
emulation on each subsequent acquisition and looks at the margin for the states in the final
surviving state of the reference bit sequence. As long as the bit sequence for the current acquisition
and the reference acquisition match, the margin is > 0. When a different decision is actually made
the margin reported is less than zero: there was less then zero margin to making a different
decision; a different decision was actually made. Even if both signals are of excellent quality, but
different, Channel Emulation with a Reference signal will catch it.
This divergence of paths through the detector may be referred to as an "error event." After a very
few bits, typically, the paths converge again. The SAM reported for the bit where the paths
converge will also be negative. This is because the reference and acquisition disagree on the
previous bit, and the state of the detector reflects the current bit and at least one previous bit (for
PR4).
WM-OM-E Rev I
375
Note: Unless a drive is in a diagnostic mode (direct write), data is scrambled and encoded when written. In the drive, after
the Viterbi detector finds the bit pattern that was written, the bit pattern is decoded and de-scrambled to recover the user
data. The DDA does not do the decoding or de-scrambling; it does not need to recover the user data in order to find
problems in the quality of the head signal or differences from a reference. This means, however, that each bit in error in the
head signal may turn into multiple bits in error in the user data (for example, if it resulted in a different valid 9 bit pattern in 8/9
encoding).
In addition, a normally operating drive tries to correct short bursts of errors in the user data using an Error Correcting Code
syndrome, so an error in the head signal may result in no bits after Error Correction if it was within the capability of the ECC
to correct it. Usually the bit error rate is measured without Error Correction to check drive operation. The ECC is only capable
of correcting a limited number of errors in a sector, so keeping the number of raw errors low is a requirement.
The SAM values shown by Channel Emulation with a reference signal directly reflect where the
DDA’s channel emulation believes an error (without Error Correction) would occur. The SAM
threshold determines the value of SAM below which a bit position is recorded on the Channel
Emulation’s "error" list. For Channel Emulation with a reference, you can set the SAM down to -1.
This allows the use of either inclusion or exclusion of positions with close to zero SAM, which might
or might not actually be an error. If the threshold is set near -1, only places where the decision to
reject the reference bit sequence was made with considerable certainty will appear in the DDA error
list. If the threshold is greater than zero, all the places where Channel Emulation calculates the bit
sequences will differ, and some places close to making an error (small positive margin) will be
included in the error list.
If Read Gate is present, it does not necessarily go false immediately after the last byte of valid
information usually error-correcting code (ECC). The delay is due to the propagation time through
the channel chip and any delays from the controller. Therefore, you can specify the amount of
"garbage" data to ignore after the end of the written data and before Read Gate goes false. Errors
detected in this area will be ignored.
When Channel Emulation with a reference signal runs, the ML markers ("+" signs) are
automatically displayed. These show the Maximum Likelihood sample sequence that the DDA’s
channel emulation chose, based on the head signal and the possible sequences. They are drawn
at the expected level at the time the channel sampled the head signal. Since Channel with
reference requires a stored reference signal, the reference trace will be overlapped with the head
signal.
The ML markers do not appear if more than 500 are needed on the display; if they are on but not
visible, zoom in on the head signal.
Channel Emulation with reference uses the same channel emulation as Channel Emulation without
reference signal.
Channel Emulation with reference requires the following setup, including a stored reference signal:
376
•
Head Signal: The VCO Synchronization field is needed at the beginning of the area to
be analyzed. If the VCO Synch field is not found, Channel Emulation with reference will
not be able to analyze the signal.
•
Reference: A reference waveform must be acquired and processed by selecting
"STORE REFERENCE" --- subsequent acquisitions will be processed and then
compared to this.
•
Signal Type: Specifies the type of PRML channel.
WM-OM-E Rev I
X-Stream Operator’s Manual
•
Adjacent Transitions (d): Corresponds to the "d" in RLL code specified as m/n(d,k) --"d" is the minimum number of non-transitions between transitions. If d=0 then adjacent
transitions are allowed. If d=1, then adjacent transitions are not permitted. For E2PR4
this field can also be set to d=2.
•
VCO Synch Pattern: In a normally operating disk drive, every time Read Gate goes
true (at the beginning of every segment to be read) there must be a repetitive signal
called the VCO Synch. It is a requirement to adjust the phase of the PLL (phase locked
loop), which generates the sampling clock, and to adjust the AGC (automatic gain
control). Most commonly the VCO Synch is 2T.
•
Bit Cell Time: is used as a starting estimate of the VCO Synch signal. If the value is
not known and the VCO Synch field is at the beginning of the area to be analyzed,
selecting Measure Bit Cell Time will determine it automatically.
•
Ignore last <n> samples: Specifies the amount of "garbage" data to ignore after the
end of the written data and before Read Gate goes false.
Additionally, the parameters below are useful (but not essential) for Channel Emulation with
reference:
•
Read Gate: If the Read Gate signal is connected to a DDA channel and specified, it will
be used to determine the regions of the signal to be analyzed. Since the VCO Synch
field is required for Channel Emulation with Reference and is normally present in the
head signal in every block just after Read Gate goes true, it is recommended that Read
Gate be used. If Read Gate is not present, the entire waveform will be used unless the
Analyze Region cursors are enabled.
•
Read Gate Polarity: Typically, Read Gate is a positive true signal. However, there are
drives that use a negative true signal for Read Gate. If Read Gate is enabled, this
setting allows you to select whether "True" is high or low.
•
Read Clock: If present, the Read Clock signal is used only to determine where the
"sample time" markers (vertical lines) are drawn.
•
Specify Region: As previously described, markers can be used to define a subset of
the head signal for analysis.
•
Filter Head Signal: If enabled, an equalization filter is applied to the head signal
before processing and display. This feature should be used if the DDA does not have
access to the drive’s equalized head signal.
After the setup is complete, a reference waveform should be acquired and saved by selecting
Store Reference.
Notes on Using Channel Emulation with Reference
1. Time misalignment between the reference and the current acquisition is made up for based
on end of VCO Synch in the first Read Gate true section. If the reference contains multiple
Read Gate true sections, we assume that their relative timing is approximately the same as
in the current acquisition.
2. It is not possible to compare a reference of one sector to each sector in an acquisition
WM-OM-E Rev I
377
containing many. It is not possible to compare a split sector with an unsplit or differently
split sector.
Using Analog Compare
This method compares a reference signal to subsequent acquisitions and looks for large changes
in the waveform. It is a general purpose test method that can be applied to finding errors in
practically any signal, including VCO Synchronization fields, data and servo-information.
The user stores a "good" reference analog waveform. On subsequent acquisitions the filter, if
selected, equalizes the newly acquired waveform. Analog Compare then attempts to measure the
bit cell time and to find the end of VCO Synch, on both the stored reference and the acquired
waveforms. If that succeeds the comparison starts, aligned by the marks at the end of VCO Synch.
If the waveforms being compared do not contain VCO Synch, or if Read Gate is not used, the
message "Could not analyze VCO Synch at start of signal" is displayed. This is just a warning, in
case it is believed that VCO Synch ought to have been found. Analog Compare will proceed
anyway.
Analog Compare computes the mean squared distance (msd) between the stored reference
waveform and the head signal, over a 3-byte-wide window. The two waveforms are aligned to the
nearest sample at the start. As the window is moved across the waveforms, alignment to the
nearest sample is maintained as long as the timing in the reference is within 1% of the timing of the
head signal. When the normalized msd exceeds the user-set Analog Threshold, an error will be
recorded on the error list; the position of the maximum difference in the reference and the head
signal is recorded. If the difference remains above threshold for more than the length of an encoded
byte, a new error is recorded at each byte. Errors are ordered in the error list from largest to
smallest difference.
Analog Compare requires some setup, and a stored reference signal to compare to before it can be
used. The following must be provided.
Head Signal: As with the other methods, the head signal is essential for Analog Compare. Unlike
the other methods, however, Analog Compare will work on any part of the head signal.
Reference: The stored reference should be acquired in the same manner (same time/div, sample
rate, trigger position, etc) as the acquisitions that will be compared to it. See Note 3 below.
Analog Threshold: This is the user-specified threshold used by Analog Compare to decide when
to record an error. A typical value for the Analog Threshold might be about 0.025. See Note 1
below.
Additionally, these parameters are useful (but not essential) for Analog Compare:
Read Gate: If the Read Gate signal is available, it will be used as described in Note 2, below.
Read Gate Polarity: Typically, Read Gate is a positive true signal. However, there are drives that
use a negative true signal for Read Gate. If Read Gate is enabled, this setting allows you to select
whether "True" is high or low.
Read Clock: If present, the Read Clock signal is used to determine where the "sample time"
markers are drawn.
Use Analyze Region: As previously described, markers can be used to define a subset of the head
378
WM-OM-E Rev I
X-Stream Operator’s Manual
signal for analysis.
Bit Cell Time: If specified, will be used to determine window size for comparison, otherwise a
default value is used.
Code Rate: If provided, this is used to determine the size of an encoded byte, which is needed in
determining the window size for Analog Compare.
Filter Head Signal: If enabled, an equalization filter is applied to the head signal before processing
and display. This feature should be used if the DDA does not have access to the drive's equalized
head signal.
After the setup is complete, a reference waveform should be acquired and saved by touching Store
Reference.
Notes on Using Head/Analog Compare
1. Setting Analog Threshold: The "Analog Threshold" sets how large the difference (mean
squared distance) between the reference and the acquisition must be to be recorded as an
"error". A threshold of zero means that even the slightest difference will be enough. The
threshold is normalized to full scale, which means that a setting of 1.000 specifies that the
signals must mismatch by full scale over the entire three byte wide analysis window to be
recorded as an error. DC mismatch is compensated and does not contribute to "mismatch".
If the waveform amplitude can be -full scale to +full scale, the formula relating threshold to
number of divisions mismatch (without vertical zoom) --- average over the analysis window
--- is: sqrt(thresh). For example, a threshold of 0.015 corresponds to 0.49 of a division
average mismatch within the window.
2. Analog Compare works best if it can analyze VCO Synch at the beginning of its analysis
region for both the reference and the head signal. If Read Gate is available it should be
able to do that. If Read Gate is not available, the "Analyze Region" cursors can be turned
on and the "start" marker positioned near the beginning of a VCO Synch field. This also will
let Analog Compare analyze the VCO Synch field and align reliably. If Read Gate is not
available, and VCO Synch is not available, then Analog Compare attempts to align the
signals up to about 12 bit cells difference. Note that if the start of the analysis region is far
from the t=0 (trigger) position then small speed variations can cause the waveforms to be
too misaligned for Analog Compare to be correct. For example, if the start of the analysis
region is 15,000 bit cell times after the trigger, a 0.1% speed variation gives 15 bit cell times
of jitter at the start of the analysis region. No matter how it achieves alignment, Analog
Compare attempts to maintain alignment for up to a 1% speed mismatch. Analog Compare
compensates for misalignment in the reference and acquisition based on the first Read
Gate edge (if a source of Read Gate has been specified), and if it can analyze VCO Synch,
on the end of the VCO Synch in that first section. If Read Gate is being used and the
reference contains multiple Read Gate true sections, then the timing between them in the
reference and the acquisitions must match within the alignment tolerance of Analog
Distance, about 12 bit cells.
3. The reference waveform must be the same as the waveforms it is compared to. That
means it must be the same length, acquired at the same horizontal and vertical scales. The
same regions of the new and reference waveform will be compared. That means it is not
WM-OM-E Rev I
379
possible to store a reference of a single sector and compare it to subsequent acquisitions
containing multiple sectors. It is also not possible to compare a split sector to an unsplit or
differently split sector. The reference and the acquisition must basically match.
Local Feature Concepts
Overview
The term "local feature computation" indicates that a parameter computed on a waveform is
determined only by information in the immediate vicinity of a specified feature of that waveform.
The DDA defines a local feature as a waveform peak followed by a trough, like this:
However, it is not the opposite --- a trough followed by a peak. The diagram below shows a single
local feature: the first peak and the trough that follows it.
380
WM-OM-E Rev I
X-Stream Operator’s Manual
Peak-Trough Identification
The key to identifying peak-trough pairs is the ability to discriminate between real pairs and false
ones. For example, noise in a signal can be mistaken for a local feature, as here:
Similarly, ‘bumps’ in a waveform may also be mistaken for peak-trough pairs.
In order to avoid such misidentification, a hysteresis argument is provided for many local feature
parameters. This essentially enables you to set a voltage band, which a peak-trough pair must
exceed in order not to be considered noise or a "bump."
The hysteresis setting is also essential to the way peaks and troughs are identified by the DDA.
The search for local features extends from the left to the right parameter cursor. But first a peak
must be found; and a waveform must rise to at least the value of the hysteresis setting in order to be
positively identified as a peak.
This peak search starts with the first waveform sample, whose voltage value is used as an initial
reference value for locating the peak. If a following waveform sample is found to be higher than the
first by an amount greater than the hysteresis setting, a peak is said to exist. Any sample lower than
the reference value, made prior to determination of a peak’s existence, is used as a new reference
point.
When a waveform rises by an amount that is more than the hysteresis, compared to the lowest prior
waveform sample, the criterion for the existence of a peak is met. Then the search for its exact
location and voltage value is initiated. Successive samples are compared to find the highest
sample. Next, two points are found, one on either side of this highest sample and down from it by at
least 25 % of the distance to the previous trough amplitude. A quadratic interpolation is then
performed on these three samples to find the new peak location and amplitude. The same
approach, using a sample lower than the highest sample by more than the hysteresis setting, is
used to locate the trough.
Local Baselines
Many parameter measurements require that the baseline of a local feature be identified. In order to
account for asymmetries due to MR heads, baselines are identified between the peak and trough,
and between the trough and the following peak.
WM-OM-E Rev I
381
The baselines are found by locating a point at which the waveform ‘rests’ between the peak and
trough and peak. These resting points are identified by statistically measuring the area of least
change in voltage value between the peak and trough or trough and peak, with internal tolerance
levels set to ensure against false baseline identification.
Another condition for identification is that the resting points must fall within a band, centered around
the midpoint of the peak and trough extremes, whose height is 2/3 of the peak-to-trough height.
If one of the baselines cannot be identified, the local baseline is set to the found value. If neither
baseline can be identified, then the local baseline is set halfway between the extremes of the local
feature’s peak and trough.
If baselines can be identified on both falling and rising slopes, the local-feature baseline is an
average of the two baselines and 1 bsep is the distance between them.
If the local feature is the last to be identified before arriving at the end of the region being analyzed,
it will not be possible to identify the trough-to-peak baseline of the following local feature. But when
the peak-to-trough baseline is identified, then these two baselines are assumed to be separated by
the same distance as the baselines for the previous local feature. And if this baseline cannot be
identified, then the local baseline becomes the midpoint of the local peak and trough.
The separation between the baselines (local baseline separation) can also be of interest in
determining the validity of certain measurements.
382
WM-OM-E Rev I
X-Stream Operator’s Manual
The following table summarizes the determination of the local baseline and its separation when the
local feature is and is not the last identified before the right parameter cursor:
Local baseline and local baseline separation if last local feature
Baseline identified
peak-to-trough (PTBase)
Local Baseline
Baseline Separation
yes
(PTBase + [PTBase + previous previous local feature’s baseline
separation])/2
separation
no
midpoint of local peak and
trough
0
Local baseline and local baseline separation if not last local feature
Baseline identified
Baseline identified
Local Baseline
Baseline Separation
peak-to-trough
(PTBase)
trough-to-peak
(TPBase)
yes
yes
average of PTBase +
TPBase
yes
no
PTBase
0
no
yes
PTBase
0
no
no
midpoint of local peak
and trough
0
PTBase - TPBase
Setting Hysteresis
Hysteresis must be set for all local parameters. The determining factors for a hysteresis value are:
1.
The maximum peak-to-peak noise in the waveform
2.
The minimum local feature amplitude
The value should be somewhere between the first and second factors to ensure that noise is not
mistaken for a local feature, and that all local features are recognized.
Local Parameters
The local parameters group offers measurements of common disk drive waveform parameters.
Local Parameter
WM-OM-E Rev I
Definition
lbase
baseline of local feature
lbsep
separation between peak-to-trough and
trough-to-peak baselines
lmax
maximum value of local feature
383
lmin
minimum value of local feature
lnum
number of local features displayed
lpp
local feature’s peak-to-trough amplitude
ltbe
time between peak-to-trough or trough-to-peak
ltbp
local feature’s time between peaks
ltbt
local feature’s time between troughs
ltmn
time of local feature’s minimum value
ltmx
time of local feature’s maximum value
ltot
local feature’s time over a % threshold
ltpt
time between local feature peak-to-trough
lttp
time between trough-to-following peak
ltut
local feature’s time under a % threshold
Note: The DDA’s variable hysteresis setting is essential to identifying peak-trough pairs.
384
WM-OM-E Rev I
X-Stream Operator’s Manual
Local Feature Parameters
lbase
Local Base
Definition The value of the baseline for a local feature.
Description The average value of the local baselines for all local features between the
parameter cursors is displayed as lbase. For histograms, each individual
baseline value for all local features between the parameter cursors is
provided.
Parameter Settings Selecting this parameter from the Measure menus prompts you for a
hysteresis setting, which allows you to set the hysteresis value to a
specified number of vertical divisions.
Example
WM-OM-E Rev I
385
lbsep
Local Baseline Separation
Definition The value of the baseline separation for a local feature.
Description The average value of the separation of the two baselines used to
calculate a local baseline is displayed for all local features between the
parameter cursors. For histograms, each individual baseline separation
value for all local features between the parameter cursors is provided.
Parameter Settings Selecting this parameter from the Measure menus prompts you for a
hysteresis setting, which allows you to set the hysteresis value to a
specified number of vertical divisions.
Example
386
WM-OM-E Rev I
X-Stream Operator’s Manual
lmax
Local Maximum
Definition The maximum value of a local feature.
Description The maximum value of all local features between the parameter cursors is
determined, and the average value is displayed as lmax. For histograms,
the maximum value of each local feature between the parameter cursors
is provided.
Parameter Settings Selecting this parameter from the Measure menus prompts you for a
hysteresis setting, which allows you to set the hysteresis value to a
specified number of vertical divisions.
Example
WM-OM-E Rev I
387
lmin
Local Minimum
Definition The minimum value of a local feature.
Description The minimum value of all the local features between the parameter
cursors is determined, and the average value is displayed as lmin. For
histograms, the minimum value of each local feature between the
parameter cursors is provided.
Parameter Settings Selecting this parameter from the Measure menus prompts you for a
hysteresis setting, which allows you to set the hysteresis value to a
specified number of vertical divisions.
Example
388
WM-OM-E Rev I
X-Stream Operator’s Manual
lnum
Local Number
Definition The number of local features in the input waveform.
Description The number of local features between the parameter cursors is
determined and displayed as lnum. One value of lnum each sweep is
provided for histograms.
Parameter Settings Selecting this parameter from the Measure menus prompts you for a
hysteresis setting, which allows you to set the hysteresis value to a
specified number of vertical divisions.
Example
WM-OM-E Rev I
389
lpp
Local Peak-to-Peak
Definition The vertical difference between the peak and trough for a local feature.
Description The peak-to-trough voltage difference is determined for all local features
in a waveform, and the average is displayed as lpp. Provided for
histograms is the peak-to-peak value of each local feature between the
parameter cursors.
Parameter Settings Selecting this parameter from the Measure menus prompts you for a
hysteresis setting, which allows you to set the hysteresis value to a
specified number of vertical divisions.
Example
390
WM-OM-E Rev I
X-Stream Operator’s Manual
ltbe
Local Time Between Events
Definition The time between a local feature peak and trough or a local feature trough
and the next local feature peak.
Description Events are defined as either peaks or troughs. The average time between
successive events in a waveform is displayed as ltbe. Provided for
histograms is the time between each successive event between the
parameter cursors
Parameter Settings Selecting this parameter from the Measure menus prompts you for a
hysteresis setting, which allows you to set the hysteresis value to a
specified number of vertical divisions.
Example
WM-OM-E Rev I
391
ltbp
Local Time Between Peaks
Definition The time between a local feature peak and the next local feature peak.
Description The average of the time between successive local feature peaks is
determined, and its value displayed as ltbp. Provided for histograms are
the times between successive peaks for all peaks between the parameter
cursors.
Parameter Settings Selecting this parameter from the Measure menus prompts you for a
hysteresis setting, which allows you to set the hysteresis value to a
specified number of vertical divisions.
Example
392
WM-OM-E Rev I
X-Stream Operator’s Manual
ltbt
Local Time Between Troughs
Definition The time between a local trough and the next local trough.
Description The average of the time between successive troughs is determined, and
its value displayed as ltbt. Provided for histograms are the times between
successive troughs for all troughs between the parameter cursors.
Parameter Settings Selecting this parameter from the Measure menus prompts you for a
hysteresis setting, which allows you to set the hysteresis value to a
specified number of vertical divisions.
Example
WM-OM-E Rev I
393
ltmn
Local Time at Minimum
Definition The time of the minimum value of a local feature.
Description The time of the minimum value of the first local feature in a waveform after
the left parameter cursor is determined. The time is returned as ltmn.
Provided for histograms are all times for local feature minimums between
the parameter cursors.
Parameter Settings Selecting this parameter from the Measure menus prompts you for a
hysteresis setting, which allows you to set the hysteresis value to a
specified number of vertical divisions.
Example
394
WM-OM-E Rev I
X-Stream Operator’s Manual
ltmx
Local Time at Maximum
Definition The time of the maximum value of a local feature.
Description The time of the maximum value of the first local feature in a waveform,
after the left parameter cursor, is determined and returned as ltmx.
Provided for histograms are all times for local feature maximums between
the cursors.
Parameter Settings Selecting this parameter from the Measure menus prompts you for a
hysteresis setting, which allows you to set the hysteresis value to a
specified number of vertical divisions.
Example
WM-OM-E Rev I
395
ltpt
Local Time Peak-to-Trough
Definition The time between a local feature peak and trough.
Description The average of the time between all local feature peaks and troughs is
displayed as ltpt. Provided for histograms are the times between
peak-trough pairs for all local features between the parameter cursors.
Parameter Settings Selecting this parameter from the Measure menus prompts you for a
hysteresis setting, which allows you to set the hysteresis value to a
specified number of vertical divisions.
Example
396
WM-OM-E Rev I
X-Stream Operator’s Manual
ltot
Local Time Over Threshold
Definition The time a local feature spends over a user specified percentage of its
peak-to-trough amplitude.
Description The peak-to-trough height of a local feature is measured. The time the
local feature spends over a user specified percent of the peak-to-trough
height is then determined. The average for all local features in a waveform
is displayed as ltot. Provided for histograms is the time spent over the
threshold by each local feature between the parameter cursors.
Parameter Settings Selecting this parameter from the Measure menus displays hysteresis
and level percent menus. The associated fields allow you to set values in
those menus: a specified number of vertical divisions or a percentage of
the peak-to-peak height of the local feature.
Example
WM-OM-E Rev I
397
lttp
Local Time Trough-to-Peak
Definition The time between a local-feature trough and the next local-feature peak.
Description The average of the time between all local feature troughs and the
following local feature peak is displayed as lttp. Provided for histograms
are the times between trough and following peak for all local features
between the parameter cursors.
Parameter Settings Selecting this parameter from the Measure menus displays hysteresis
and level percent menus. The associated fields allow you to set values in
those menus: a specified number of vertical divisions or a percentage of
the peak-to-peak height of the local feature.
Example
398
WM-OM-E Rev I
X-Stream Operator’s Manual
ltut
Local Time Under Threshold
Definition The time a local feature spends under a user-specified percentage of its
peak-to-trough amplitude.
Description The peak-to-trough height of a local feature is measured. The time the
local feature spends under a user-specified percentage of this height is
determined, and the average for all the waveform’s local features is
displayed as ltut. Provided for histograms is the time spent under the
threshold by each local feature between the parameter cursors.
Parameter Settings Selecting this parameter from the Measure menus displays hysteresis
and level percent menus. The associated fields allow you to set values in
those menus: a specified number of vertical divisions or a percentage of
the peak-to-peak height of the local feature.
Example
WM-OM-E Rev I
399
Disk Standard Parameters
These parameters enable standard disk drive waveform parameter measurements. These
parameters are accessible by touching Measure in the menu bar, then touching the My Measure
button, and then a parameter button: P1 to P8.
DISK STANDARD PARAMETER
DEFINITION
aasym
amplitude asymmetry between taa+ and taa-
p@lv
period of each cycle in an acquired waveform,
called Jitter in the parameter menu
nbph
narrow band phase of waveform Discrete Fourier
Transform (DFT)
nbpw
narrow band power of waveform Discrete Fourier
Transform (DFT)
owrt
overwrite
pw50
pulse width of peaks at 50% amplitude from
baseline
pw50+
pulse width of positive peaks at 50% amplitude
from baseline
pw50
pulse width of negative peaks at 50% amplitude
from baseline
res
resolution
taa
track average amplitude
taa+
track average amplitude of positive peaks from
baseline
taa
track average amplitude of negative peaks from
baseline
All disk standard parameters except nbph, nbpw, owrt and p@lv make their measurements on
waveform peak-trough pairs. In addition, several of the parameters determine the baseline of
peak-trough pairs in order to perform their calculations.
Note: The DDAs variable hysteresis setting is essential for identifying peak-trough pairs.
400
WM-OM-E Rev I
X-Stream Operator’s Manual
ampl asym
Amplitude Asymmetry
Definition
aasym = 1 [ |(taa+ - taa-)| / (taa+ + taa-)]
Description
For a perfectly symmetric waveform, aasym=1. If any one side of the
waveform is missing, aasym=0.
Parameter Settings
Selecting this parameter displays a hysteresis-dialog for setting the
hysteresis value to a specified number of vertical divisions.
p@lv
Period at Level
Definition
Calculates the period of each cycle in an acquired waveform
Description
For each cycle in a waveform, p@lv determines the time from the
beginning of the cycle as defined by a user specified threshold and slope
to the end of the cycle as shown in the diagram below.
Parameter Settings
Selecting this parameter accesses a dialog to set hysteresis, level and
slope. A hysteresis value defines the hysteresis, in divisions. That is, a
voltage band is extended equidistantly above and below the selected
level. In order for the signal to be considered valid, and not as noise, the
signal must exceed the upper or lower limits of this band by half the
hysteresis-division setting.
WM-OM-E Rev I
401
nbph
Narrow Band Phase
Definition
Provides a measurement of the phase at a specific frequency for a
waveform.
Description
nbph is the phase of the Discrete Fourier Transform (DFT) computed on a
waveform at a specific frequency. The result is the phase of the
corresponding frequency sine wave component of the waveform at the
first data point between the parameter cursors. The nbph parameter
calculates one bin of a DFT centered at the frequency provided. The bin
width is 0.105% of the frequency selected if the waveform trace displayed
by the DDA is 960 x (1/frequency) or more in length (i.e., the trace is equal
to or longer than 960 cycles of a waveform at the selected frequency).
Otherwise, the bin width is:
100 / integer[(trace length)/(1/frequency)] %,
where integer[ ] designates discarding any fractional portions in the result.
Thus, if the waveform trace is 48.5 times longer than 1/frequency, the bin
width will be:
100/48 = 2.1% of the selected frequency.
nbph is very sensitive to frequency, and it is important that the frequency
value provided be as accurate as possible if accurate results are to be
obtained.
Parameter Settings
402
Selecting this parameter accesses a frequency setting dialog.
WM-OM-E Rev I
X-Stream Operator’s Manual
nbpw
Narrow Band Power
Definition
Provides a measurement of the power at a specific frequency for a
waveform.
Description
nbpw is the magnitude of the Discrete Fourier Transform (DFT) computed
on a waveform at a specific frequency. nbpw calculates one bin of a DFT
centered at the frequency provided. The bin width is 0.105% of the
frequency selected if the waveform trace on the DDA is 960*
(1/frequency) or more in length (i.e. the trace is equal to or longer than
960 cycles of a waveform at the selected frequency). Otherwise, the bin
width is:
100 / integer[trace length/(1/frequency)] %,
where integer[ ] designates discarding any fractional portions in the result.
Thus, if the waveform trace is 48.5 times longer than 1/frequency then the
bin width will be:
100/48 = 2.1% of the selected frequency.
A Blackman-Harris window is applied to the input data to minimize
leakage effects. The net result is that nbpw will provide excellent results
even if frequency changes occur due to spindle speed variations. If the
actual frequency differs from the specified frequency, and the bin width is
0.105% (minimum resolution bandwidth), the resulting power will be
reduced from the actual as in this table:
Frequency Difference dB Reduction
0.03% 0.3 dB
0.06% 1.1 dB
0.1% 3 dB
If the bin width is greater than 0.105%, the frequency difference for which
a specified dB reduction will occur will scale proportionally to the bin
width/0.105.
nbpw results are presented in dBm.
Parameter Settings
WM-OM-E Rev I
Selecting this parameter accesses a frequency setting dialog.
403
owrt
Overwrite
Definition
The ratio of residual to original power of a low-frequency disk waveform
overwritten by a higher frequency waveform.
Description
owrt measures the residual power of a low-frequency LF waveform after it
has been overwritten by a high-frequency HF waveform. The LF
waveform should be stored to memory (M1-M4). The HF waveform can
then be input to the DDA, and overwrite calculated where:
owrt = 20 log (Vr/Vo),
where Vr is the residual Vrms of the sine wave component of the HF
waveform at the LF base frequency after the HF waveform write, and Vo is
the Vrms of the sine wave component of the LF waveform at the LF base
frequency. The calculation is performed by the DDA making a
narrow-band power measurement (see nbpw parameter description) at
LF, for both the HF and LF waveforms, and subtracting the second result
from the first. A menu enables the choice of which waveform, HF or LF, is
assigned to which DDA channel or trace (1, 2, 3, 4, M1 to M4, or F1 to F8).
The menu button is used to set the input for HF or LF, while the input for
the selected waveform is set with the associated knob. The owrt results
are presented in dB. All averaging, including statistics and trend average,
is performed on linear units. Average results are converted to dB.
Note: In typical use, it is preferable to use nbpw to measure the LF
waveform, and then the residual LF in the HF separately, instead of the
owrt parameter. Overwrite is the difference between the nbpw readings in
dB. There are two reasons why this is preferable: 1) nbpw, with statistics
on, provides average power readings. With owrt the low frequency signal
is typically a stored single-shot acquisition due to the difficulty finding a
suitable trigger for time domain averaging of a head signal. 2) owrt
computes both nbpw results each time. If the LF is stored, this is not
necessary. So nbpw will take twice as many acquisitions as owrt and
achieve a more stable average result in the same amount of time.
Parameter Settings
404
Selecting this parameter accesses a frequency setting dialog. This
frequency is used to calculate nbpw for both the HF and LF waveforms. If
a large number of digits is used, selection of the exact frequency may be
difficult. In this case, a number with fewer digits and less precision should
be chosen for the approximate frequency, then the precision should be
increased as desired and the exact value chosen.
WM-OM-E Rev I
X-Stream Operator’s Manual
pw50
Pulse Width 50
Definition
The average pulse width at the 50% point between a local baseline and
the local-feature peak, and between the local baseline and the local
feature-trough.
Description
All local features between the parameter cursors for an input waveform
are identified. The local baseline is identified for each feature, and the
height between the local baseline and the peak is determined. The pulse
width is measured at 50% of the peak. The same measurement is then
performed for the trough. The average of all width measurements is
displayed as pw50. Provided for histograms is the average pw50 value for
each local feature between the parameter cursors.
Parameter Settings
Selecting this parameter displays a hysteresis-dialog for setting the
hysteresis value to a specified number of vertical divisions.
pw50-
Pulse Width 50-
Definition
The average pulse width measured at the 50% point between the local
feature baseline and the local feature trough.
Description
All local features between the parameter cursors for an input waveform
are identified. The local baseline is identified for each feature, and the
height between the local baseline and trough is determined. The pulse
width is measured at 50% of the trough amplitude. The average of all
width measurements is displayed as pw50. Provided for histograms is the
average pw50 value for each local feature between the parameter
cursors.
Parameter Settings
Selecting this parameter displays a hysteresis-dialog for setting the
hysteresis value to a specified number of vertical divisions.
WM-OM-E Rev I
405
pw50+
Pulse Width 50+
Definition
The average pulse width at the 50% point between the local feature
baseline and the local feature peak.
Description
All local features between the parameter cursors for an input waveform
are identified. The local baseline is identified for each feature, and the
height between the local baseline and peak is determined. The pulse
width is measured at 50% of the peak amplitude. The average of all width
measurements is displayed as pw50+. Provided for histograms is the
average pw50+ value for each local feature between the parameter
cursors.
Parameter Settings
Selecting this parameter displays a hysteresis-dialog for setting the
hysteresis value to a specified number of vertical divisions.
res
Resolution
Definition
The ratio of the track average amplitude for a high and low frequency
waveform.
Description
res returns, as a percentage, the ratio of track average amplitude (see taa
parameter description) for a low frequency LF and high frequency HF
waveform:
res = (taa(LF) / taa(HF)) * 100%.
Parameter Settings
Selecting this parameter displays a hysteresis-dialog for setting the
hysteresis value to a specified number of vertical divisions.
taa
Track Average Amplitude
Definition
The average peak-to-trough amplitude for all local features.
Description
All local features between the parameter cursors for an input waveform
are identified. The peak-to-trough amplitude is determined for each
feature, and the average is returned as taa. Provided for histograms is the
peak-to-trough amplitude for each local feature between the parameter
cursors.
Parameter Settings
Selecting this parameter displays a hysteresis-dialog for setting the
hysteresis value to a specified number of vertical divisions.
taa-
Track Average Amplitude-
Definition
The average local baseline-to-trough amplitude for all local features.
406
WM-OM-E Rev I
X-Stream Operator’s Manual
Description
All local features between the parameter cursors for an input waveform
are identified. The local baseline-to-trough amplitude is determined for
each feature, and the average is returned as taa. Provided for histograms
is the local baseline-to-trough amplitude for each local feature between
the parameter cursors.
Parameter Settings
Selecting this parameter displays a hysteresis-dialog for setting the
hysteresis value to a specified number of vertical divisions.
taa+
Track Average Amplitude+
Definition
The average local baseline-to-peak amplitude for all local features.
Description
All local features between the parameter cursors for an input waveform
are identified. The local baseline-to-peak amplitude is determined for
each feature, and the average is returned as taa+. Provided for
histograms is the local baseline-to-peak amplitude for each local feature
between the parameter cursors.
Parameter Settings
Selecting this parameter displays a hysteresis-dialog for setting the
hysteresis value to a specified number of vertical divisions.
WM-OM-E Rev I
407
Disk PRML Parameters
These enable parameter measurements of auto-correlation signal-to-noise (ACSN) and non-linear
transition shift (NLTS). The calculation of both parameters is based on a correlation math function.
•
ACSN can be applied to any periodic waveform. Since these waveforms are by definition
identical in every period, any deviation is due to uncorrelated noise sources. By performing
an auto-correlation calculation of the waveform over successive periods, the level of
less-than-perfect correlation can be measured. With this measurement, the noise level can
be derived by ACSN. (See ACSN description.)
•
NLTS offers the ability to measure all echoes in the auto-correlation calculation of a disk
waveform. This includes the NLTS (adjacent location), second adjacent location, and
overwrite (initial magnetization) echoes. The parameter performs NLTS averaging, pattern
length searching, and limit checking to reduce the effects of noise and to ensure accurate
measurements. (See NLTS description.)
Correlation Theory of Operation
The DDAs correlation function measures the correlation between one section of a waveform and
other sections of the same waveform having the same length, or between a section and sections of
equal length belonging to another waveform.
When the correlation is performed on the same waveform it is called an auto-correlation. If the
shape of two waveform sections are identical, the correlation value will be maximized.
The DDA normalizes correlation values to +/-1, with 1 indicating that the waveform sections are
identical, -1 that the sections are inverted from each other, and 0 that there is no correlation.
Noiseless periodic waveforms will have perfect correlation (a correlation value of 1) when
performing auto-correlation, and when the start of the second section is an integer number of
periods later than the start of the first section.
Correlation values can be calculated as a function of various amounts of time shift between two
waveform sections used in calculating a correlation. This calculation, as a function of the starting
point of the second section being the ith waveform sample, is determined by:
408
WM-OM-E Rev I
X-Stream Operator’s Manual
where Corri is the ith sample point (starting from 0) of the correlation waveform, wave1j is the jth
sample of the first waveform, wave2 is the second input waveform (wave1 in an auto-correlation),
and
is a section of a waveform from sample a to sample b. The upper bound N in the
summations determines the length (length is N+1 sample points, since the first sample is point 0) of
the waveform sections on which the correlation calculation is performed. The divisor in the
correlation function:
normalizes the correlation calculation to +/-1, while the
term in the dividend removes any effect due to DC offset of the input waveforms in the correlation
function.
Essentially, the correlation waveform function takes a section of the first waveform and calculates
how it correlates with an equal-length section of a second waveform, using different starting points
in the second waveform. This can be visualized as taking a section of waveform 1, sliding it over
waveform 2, and calculating the correlation value for the area that overlaps. The bounds of the
starting point are from the beginning of the second waveform to its length, minus the section length.
At the upper bound, the end of the first waveform section lies at the last sample point of the second
waveform. Because the length of waveforms in the DDA is limited to 10 divisions, the upper bound
of the correlation function is 10 divisions minus the section length in divisions.
WM-OM-E Rev I
409
acsn
Auto-Correlation Signal-to-Noise
Definition
Provides a signal-to-noise ratio for periodic waveforms.
Description
Using the DDA’s correlation function, acsn provides a measurement of the
auto-correlation signal-to-noise for a repetitive waveform. At least two waveform
repetitions need to be acquired in order to calculate acsn. In addition, the period
of the waveform must be specified.
Selecting this parameter displays a hysteresis-dialog for setting the hysteresis
value to a specified number of vertical divisions.
The parameter then verifies, and may adjust, the period based on the value
provided. This is crucial because variations in disk rotation speed make the exact
length of time for a disk waveform difficult to determine.
Using the period as a starting point, the DDA performs an auto-correlation and
looks for an auto-correlation peak at the period. At the top of the peak, the pattern
repeats. The DDA locates the top and notes the corresponding time so that it can
determine the period. Then it recalculates the auto-correlation using this period.
The value of the auto-correlation at the period peak, R, is used to calculate the
ACSN as:
S/N = R/(1R),
ACSN = 10* log10 S/N.
For greater accuracy, the instrument averages several ACSN measurements
when calculating acsn. An ACSN measurement is performed for each pattern,
and the results averaged.
All individual ACSN measurements can be observed by histogramming the acsn
parameter. ACSN is limited to measuring signal-to-noise ratios of 9.6 dB or
greater.
ACSN results are presented in dB. All averaging, including statistics and trend
average, is performed on linear units. Averaged results are then converted to dB.
410
WM-OM-E Rev I
X-Stream Operator’s Manual
Parameter
Settings
When you select acsn from the PRML dialog's With parameter field (DRIVE
ANALYSIS Æ Measure Æ Parameter Set Æ PRML) an acsn Pattern Length field
appears also.
The pattern length should be set as an integral number of waveform periods, and
must be at least 50 samples at the DDA’s sample rate. (The sample rate is shown
in the TimeBase label box.) Because these periods will be correlated with the
same number of following periods, the pattern length must be no more than half
the number of full periods available in the sweep.
Notes on How Settings Affect ACSN Measurement
Pattern length should be close enough to the signal period (or multiple thereof)
that it is on the correlation peak. The code measures correlation at 3 positions: the
length, 6 samples less and 6 samples more. It will walk up a slope until the center
sample is highest, tighten the spacing until the two side positions have correlation
above half the correlation at the center position, and eventually perform a
parabolic fit. But if pattern length misses the peak entirely then this search may not
work if the smallest of the three correlations is at the center and the two side
position correlations are equal, it stops. For a sinusoidal signal, almost any setting
of pattern length should work.
One limitation to know about at this stage: the code checks for a "reasonable"
peak. The correlation at the center position must be > 0.9, or the parameter
computation is canceled. This is done without the benefit of the parabolic fit, but
the intent is only to make sure of a reasonable peak.
The total number of cycles in the acquisition does not affect the ACSN result for a
stationary signal. Note that horizontal scale and the Max Sample Points entry on
the TIMEBASE "Smart Memory" dialog interact. As you increase the time of an
acquisition, the sample rate may decrease to keep the acquisition smaller than
Max Sample Points. Although ACSN is not affected by horizontal scale, it is
affected by sample rate. Be sure to keep it high enough.
For the same signal, ACSN will fall as vertical scale is increased, because the
signal fills less of the code space of the ADC and is therefore more contaminated
by quantization noise and any other internal noise. In general, when displayed on
a channel (or a reset trace), the signal should fill as much of the grid vertically as
possible, but should never clip against the top or bottom of the grid. If high ACSN
readings (greater than or equal to 30 dB) are expected, this is especially
important.
The pattern length should be kept to the minimum number of cycles that will
satisfy the 50 samples per pattern requirement. In general, with a somewhat noisy
signal, as the number of cycles in one pattern length is increased, ACSN is slightly
reduced. For example, with an 80 MHz 75 mV sine wave with 0.6% (of p-p) rms
noise, sampled at 1GS/s, acsn result varied with pattern length as follows:
WM-OM-E Rev I
411
Pattern Length (Seconds)
Cycles in One Pattern
Length
ACSN
5.00E-8
4
27.54 dB
6.25E-8
5
26.97 dB
7.50E-8
6
26.78 dB
8.75E-8
7
26.57 dB
1.000E-7
8
26.47 dB
1.125E-7
9
26.41 dB
1.250E-7
10
26.30 dB
As ACSN readings get higher, small amounts of noise cause greater changes in
dB. This is because high readings mean correlation was very close to 1.
Examples:
412
Correlation
ACSN
.9995
33.0 dB
.9990
30.0 dB
.9985
28.2 dB
.9980
27.0 dB
.9975
26.0 dB
.9970
25.2 dB
WM-OM-E Rev I
X-Stream Operator’s Manual
nlts
Non-Linear Transition Shift
Definition
Provides a measurement of the nonlinear transition shift for a disk drive signal.
Description
Using the DDA’s correlation function, nlts measures the nonlinear transition
(adjacent location) shift. At least two full cycles of the test sequence are required
for the auto-correlation. In addition, the period of the waveform must be specified.
The parameter then verifies, and may adjust, the pattern length based on the
value provided. This is crucial, because variations in disk rotation speed make the
exact pattern length for a disk waveform difficult to determine.
Using the pattern length as a starting point, the DDA looks for an auto-correlation
peak at the length. At the top of the peak, the pattern repeats. The DDA locates
the top, and notes the corresponding time so as to determine the exact pattern
length. Then it recalculates the auto-correlation, using this length. If the value of
the auto-correlation peak at the pattern length is less than 0.9, the NLTS is not
calculated. This is because the pattern-length sections will be too uncorrelated to
provide a meaningful result. Otherwise, the pattern length value is used to
calculate nlts. Using the pattern delay value, the DDA measures the
auto-correlation coefficient for the first pattern-length chunk of the input waveform
with a second pattern-length chunk, starting from the beginning of the input
waveform at the delay value.
In order to correctly calculate nlts, the disk drive waveform must be a
pseudorandom sequence that will create an echo in an auto-correlation
calculation, corresponding to the non-linear transition shift. Typically, this
waveform is a 127-bit pattern based on an x7 + x3 + 1 polynomial; and the NLTS
echo appears at a pattern delay of 20.06% of the input pattern length. Ideally, the
value of NLTS is:
NLTS(%) = 200* Correlation Coefficient (at delay).
However, because noise in the input waveform can affect the correlation
coefficients value, the DDA averages several NLTS measurements to reduce the
effect of noise. An NLTS measurement is performed for each pattern, and the
results averaged. All the individual NLTS measurements can be observed by
histogramming the nlts parameter.
The greater the number of pseudorandom pattern periods in the input waveform,
the greater the reduction in the effect of noise on the nlts result. In order to further
reduce the impact of noise, the NLTS calculations are adjusted by dividing their
value by the correlation coefficient value at an integral number of pattern-length
delays.
The following table gives the standard deviation of the nlts parameter for varying
amounts of auto-correlation signal-to-noise, and numbers of repetitions of the
pseudorandom sequence in the input waveform. The sampling rate used was four
samples/bit cell, and the input waveform had 20% NLTS.
WM-OM-E Rev I
413
ACSN
#Pattern
Repetitions
nlts Standard
Deviation
26 dB
2
0.44 %
10
0.28 %
25
0.20 %
2
0.59 %
10
0.32 %
25
0.26 %
2
0.65 %
10
0.42 %
25
0.28 %
2
1.08 %
10
0.57 %
25
0.35 %
23 dB
20 dB
17 dB
414
WM-OM-E Rev I
X-Stream Operator’s Manual
Parameter
Settings
When you select nlts from the PRML dialog's With parameter field (DRIVE
ANALYSIS Æ Measure Æ Parameter Set Æ PRML) an nlts Pattern Length field
and pattern Delay field appear also. You can adjust the mantissa, exponent or
number of mantissa digits using the pop-up numeric keypad. The pattern length
should be set to the pattern period.
Although the DDA searches for the correct pattern length, the value provided
needs to be sufficiently close to the actual pattern length for nlts to perform the
search. A 1 µs pattern may, for example, accept a range of 1 µs +/- 40 ns. Within
this range, a value for nlts will be provided. Otherwise "---" appears on the screen,
indicating that no measurement can be made.
The pattern Delay setting is a percentage of the pattern length. The DDA will
internally scale the delay value entered by the ratio of the pattern length calculated
internally to the pattern entered by you. Several disk drive waveform attributes can
be measured by using different delay values. The following table provides delay
values to enter for the commonly used 127-bit pseudo-random sequence (x7 + x3
+ 1 polynomial) when measuring various waveform attributes:
Waveform Attribute
Bit Cell
Location
Delay (%)
Adjacent Location
25.5
20.08%
2nd Adjacent Location
-30.5
-24.02%
Initial Magnetization
45.5
35.83%
Interaction Interference
-60.5
-47.64%
Notes
The pattern Delay tells the DDA where in the repeating pattern to measure NLTS.
NLTS is calculated from the correlation coefficient at that time. Correlation is
calculated at 3 sample times: the nearest sample time and one on each side. A
curve fit is performed to calculate a better estimate of the true peak height.
As described above, the nlts parameter only requires one waveform. Each
acquisition must contain only the pseudorandom repeating sequence (PRS), not a
servo wedge or a preamble. It does not matter where in the PRS the acquisition
begins; its echo properties are independent of starting point. There must be at
least two repetitions of the pattern in each acquisition. A reasonable number
would be about 25 repetitions (32 repetitions of a 127-bit sequence should fit in a
sector).
NLTS requires at least 5 samples per PW50 for acceptable accuracy. More is
better.
WM-OM-E Rev I
415
The PRS data must correspond to the transitions on the media. This means it
must be written in direct write mode; it must not be scrambled or encoded.
NLTS calculated by correlation techniques and by the fifth harmonic elimination
techniques do correlate, but they are not identical. Fifth harmonic elimination uses
a pattern including only dibits and widely spaced transitions. Of course, a dibit is
the worst case for NLTS. The pseudorandom pattern has some dibits, some
tribits, some transitions 1 apart, etc. The reading that any method based on a PRS
comes up with is affected by all of the pattern. This tends to make the correlation
method come up with a somewhat lower value than fifth harmonic. That is the
better value to look at when determining write precomp, since the PRS is a lot like
real data.
The fifth harmonic method is not sensitive to amplitude asymmetry. Its drawbacks
are
•
If the fifth harmonic is small, noise will tend to inflate the value read: for 20
dB SNR it may not be possible to read below 10% nlts
•
Amplitude loss due to partial erasure will contribute to the fifth harmonic
about as much as actual NLTS.
The correlation method is less sensitive to amplitude loss due to partial erasure:
one reference cites experiments showing that 25% nlts and 25% amplitude loss
only inflates the nlts reading to 30%.
However, it is more sensitive to PW50/T ratio (it is most accurate at high ratio,
approaching 3.0). Partial erasure and hard/easy transition shift (due to DC erase)
creates separate correlation echo peaks which, depending on the pattern used,
may be close to the adjacent transition nlts echo and interfere. It is important to
pick a good PRS.
416
WM-OM-E Rev I
X-Stream Operator’s Manual
Noise Parameters
Disk noise parameters enable parameter measurements of media signal-to-noise (msnr), residual
(electronics) signal-to-noise (rsnr), and the ratio of media to residual signal-to-noise (m_to_r). The
calculation of all three parameters is based on the distribution of the averaged Viterbi input
samples.
•
msnr can be applied to any single-frequency, sector-based data pattern. The
single-frequency data will be sampled at the peaks (maxima), zero crossings, and troughs
(minima). Any deviations from the ideal sample points will be a result of noise. By
performing multiple reads, random noise can be averaged away. With this measurement,
the repeating media noise level can be derived by msnr.
•
rsnr can be applied to any single-frequency, sector-based data pattern. The
single-frequency data will be sampled at the peaks (maxima), zero-crossings, and troughs
(minima). Any deviations from the ideal sample points will be a result of noise. By
performing multiple reads, random noise can be quantified. With this measurement, the
non-repeating residual (electronics) noise level can be derived by rsnr.
•
m_to_r can be applied to any single-frequency, sector-based data pattern. The m
•
snr is compared with the rsnr. The resulting ratio indicates whether the signal is dominated
by media noise if it is greater than 1.00, or dominated by residual (electronics) noise if less
than 1.00.
Note: Although the math on the following pages is simplified by assuming a large number of sweeps, inside the DDA it
calculates what the final value should be from 2 or more sweeps. The value will become more stable as more sweeps are
taken, but its mean should not change. Therefore, a large number of sweeps is not required for unbiased values.
WM-OM-E Rev I
417
msnr
Media Signal-to-Noise Ratio
Definition
Provides a signal-to-noise ratio for single-frequency, sector-based waveforms.
Description
Granularity in magnetic media produces zigzag transitions. The exact location of
the zigzags changes from write to write causing media noise (also known as
zigzag noise). During read operations, the read head effectively averages across
the track the location of all the zigzags. If the recorded track width is wide, there
are many zigzags and very little variability in the averaged transition location. If the
track width is narrow, there are fewer zigzags, and the variability in the averaged
transition location increases.
Head signal amplitude is approximately proportional to track width. Media noise is
approximately proportional to the square root of the track width. Therefore, the
ratio of the head signal to the media noise (msnr) is proportional to the square root
of the track width. As track widths continue to decrease, msnr will get worse.
Although advanced head technology (i.e., MJR and GMR) can increase the head
signal output for a given track width, the effect of media noise on the head signal is
also increased so there is no improvement in msnr. As track widths decrease,
msnr will continue to increase despite greatly improved head technology.
By using single-frequency data, the algorithm is able to focus on the peaks, the
zero-crossings, and the troughs. The ideal Viterbi input samples are therefore +1,
0, and -1. Deviations from the ideal are quantified and graphed. The squared
sigma of the total noise distribution is equal to the squared sigma of the media
noise distribution. This relationship is always true:
σt2 = σm2 + σr2
For a large number of samples:
σm2 = σa2
σr2 =σ t2 - σa2
Once the distribution of the media noise has been calculated, the msnr is then
calculated by:
msnr = 20 log(v0-p/σm)
Parameter
Settings
418
After specifying the location of the “Head Signal” and the optional “Read Gate,”
selection of msnr is automatic after you touch the Noise Analysis button. Touch
the Setup for Single Frequency button to initialize the measurement.
WM-OM-E Rev I
X-Stream Operator’s Manual
rsnr
Residual Signal-to-Noise Ratio
Definition
Provides a residual signal-to-noise ratio for single-frequency, sector-based
waveforms.
Description
Residual noise is the random noise present on a disk drive signal from read to
read.
By using single-frequency data, the algorithm is able to focus on the peaks,
zero-crossings, and the troughs. The ideal Viterbi input samples are therefore +1,
0, and -1. Deviations from the ideal are quantified and graphed. The squared
sigma of the total noise distribution is equal to the squared sigma of the media
noise distribution and the squared sigma of the residual noise distribution. This
relationship is always true:
σt2 = σm2 + σr2
For a large number of samples:
σm2 = σa2
σr2 = σt2 - σa2
Once the distribution of the media noise has been calculated, the rsnr is then
calculated by:
rsnr = 20 log(v0-p/σr)
Parameter
Settings
After specifying the location of the “Head Signal” and the optional “Read Gate,”
selection of rsnr is automatic after you touch the Noise Analysis button. Touch
the Setup for Single Frequency button to initialize the measurement.
m_to_r
MSNR-to-RSNR Ratio
Definition
Provides a media signal-to-noise residual to signal-to-noise ratio for
single-frequency, sector-based waveforms.
Description
The m_to_r ratio provides a quick measurement to compare the media noise with
the residual noise. If this ratio is greater than 1.00, the signal is residual, or
electronics noise dominated.
The measurement is calculated by:
m_to_r = σm/σr
Parameter
Settings
WM-OM-E Rev I
After specifying the location of the “Head Signal” and the optional “Read Gate,”
selection of m_to_r is automatic after you touch the Noise Analysis button. Touch
the Setup for Single Frequency button to initialize the measurement.
419
PRML Channel Emulation
This introduction to PRML and its concepts explains the role of the PRML channel chip components.
It describes how the Channel Emulation feature of the Disk Drive Analyzer works together with
them using equalization, clock and gain recovery, maximum likelihood detection, sequenced
amplitude margin, and encoding and error detection.
Why PRML?
For the remarkable gains in disk drive capacity to continue, media and head performance
improvements are no longer enough. Faced with equally impressive advances in semiconductor
technology, disk drive engineers have been working to create a new read-channel architecture that
will allow capacity to grow unimpeded.
The answer lies in the construction of the disk itself. The disk’s magnetic poles, with two
orientations possible along the track, store the bits as "0" and "1". When the drive reads, the head
detects the transition from one pole to another --- as bit "0" to bit "1", for instance. If such transitions
are "far away," or low-density, the drive will see isolated pulses. But to increase density, the pulses
can be made shorter and placed closer together or kept wide but overlapping. While the first of
these alternatives, represented by Peak-Detect systems, has reached its limits, the second,
Partial-Response Maximum Likelihood (PRML), has allowed the industry to go on boosting
capacity.
The overlapping pulses of partial-response systems allow much greater density. PRML systems
have more samples per pw50, which is defined as the width of an isolated pulse at 50% of its
amplitude. And the more complex, or higher-order, the PRML system, the greater the density that
can be obtained. Comparing typical values achieved by available PRML systems with Peak-Detect
we find:
420
WM-OM-E Rev I
X-Stream Operator’s Manual
Density of Samples per pw50
Peak Detect
1
PRML
PR4
1.65
EPR4
2
E2PR4
2.31
However, the higher order PRML schemes need very complex circuits and decoders. While the
Class IV partial response (PR4) system works with three vertical levels of samples, extended
partial response 4 (E2PR4) has seven levels, and requires not only a higher resolution of ADC, but
a complicated timing and gain recovery circuit and sophisticated ML detector as well. Another
disadvantage of the more complex PRML schemes is that they are more sensitive to noise.
Principle of Equalization
The process of taking the more-or-less Lorentzian shaped head response to a magnetic transition
and turning it into a correctly shaped pulse is called equalization. This is of great importance, due to
the need of the Viterbi detector inside the PRML channel chip for correctly shaped pulses.
Essentially, equalization is performed in the read channel chip by a continuous time analog filter
(CTAF).
Noise must be eliminated before sampling occurs, or else it becomes impossible to separate it from
the head signal. Since the head signal is typically noisy, and contains pulses that are not quite the
desired shape, the DDA provides an equalization filter to reduce much of the noise and reshape the
pulses before it processes the waveform. This filter is a digital implementation of a seven-pole,
two-zero equiripple filter.
When you are using the filter, there are a number of parameters to be set. If the head signal has
already been acquired, the filter parameters can be set automatically by pressing the Train Filter
button. When this button is pressed:
•
If the signal type is Peak Detect, the boost is set to zero and the -3 dB frequency is set
to:
•
If the signal type is PRML (PR4, EPR4 or E2PR4) the -3 dB frequency is set to:
The best boost and -3 dB frequency are found by optimizing boost at the default -3 dB frequency,
then optimizing -3 dB at the better boost. Then optimize boost at the new -3 dB frequency, and
optimize -3 dB frequency again at the new boost. And then, if -3 dB frequency has changed by
more than a small amount, optimize the boost one final time. The goal for optimization is to
maximize the mean of the 100 worst SAM values. A typical run will recompute the filter, apply it, and
WM-OM-E Rev I
421
run the Viterbi detector on the filtered waveform fifteen to twenty times. While the filter training is in
progress, a message is displayed showing the last boost and -3 dB settings and the mean of the
100 worst SAM values at that setting.
The result of training is a close approximation to the best settings for our digital version of a CTAF
on the current acquisition, using the current setup of the FIR. The cleaner the waveform, the better
the approximation will be. The filter should be trained on a signal from a good read, those settings
can be used for all reads in the same zone.
Train Filter should be done with the acquisition stopped (press STOP on the DDA), so that the
same waveform is worked on each time; otherwise the search may be slow to converge. Train
Filter can take a significant amount of time, and it is recommended that it be done on relatively
short waveforms of 50 or 100 kpoints. Once trained, the memory length can be adjusted to the
desired length. To ensure that the group delay is flat, the filter requires at least five samples per bit
cell. This is not a hard limit, but performance will degrade with fewer than five samples per bit cell.
Alternatively, you can adjust the filter settings manually.
-3 dB Frequency
This is the actual -3 dB frequency of the filter. In most implementations of frequency cutoff (fc), the
-3 dB point, if Boost is 0 dB and group delay is 0%, is controlled by you. It is understood that the real
-3 dB frequency will be higher by some factor that depends on Boost and Group delay settings.
Therefore changing Boost or Group delay requires changing "fc" in order to keep the -3 dB point in
the same place.
The DDA does this work automatically: you set the desired -3 dB frequency, and the DDA
calculates fc for the current Boost and Group delay.
The frequency cutoff accuracy (alpha = 0) is < 2% of the setting.
Boost at fc
The pulse shape produced by a transition going under a head is nearly Lorentzian, but that is not
the correct shape for PRML. Boosting the gain at high frequencies makes the pulses slimmer and
eliminates the long tails they would otherwise have. The perfect (mathematically created) shape
that an isolated pulse should have is illustrated below, for PR4, EPR4 and E2PR4. Note that the
vertical lines show when the channel samples the waveform.
The boost accuracy is within 0.5 dB of the setting:
422
WM-OM-E Rev I
X-Stream Operator’s Manual
Group Delay
The delay through the filter of the lowest frequencies can be adjusted. The normal setting is 0.0%
adjustment; that is, flat response. This is used to compensate for group delay distortion before the
filter. Group delay setting is unaffected by Train Filter.
The digital implementation of our equalizing filter does not have perfectly flat group delay. The
non-flatness increases with the ratio of -3 dB frequency to sampling rate and with boost. The DDA
requires 5 samples per bit cell, which means that the -3 dB frequency will be 10% of sampling rate.
If this requirement is met, group delay should be sufficiently flat. E2PR4 is especially sensitive to
non-flat group delay. For E2PR4, especially if the "5 samples per bit cell" requirement is not met, it
will probably be beneficial to set the "Group Delay" field to a small positive number, perhaps 6% or
so. This helps flatten the group delay of our equalizer filter.
WM-OM-E Rev I
423
Resampling ADC
Because the DDA data is already digital, this simply interpolates between DDA samples to produce
a digital value at the channel sample time.
Finite Impulse Response (FIR)
In addition to the continuous time analog filter (CTAF), there is normally an FIR filter following the
analog-to-digital converter at the PRML channel’s sample rate. Its purpose is to ‘adapt’ and
fine-tune equalization. The DDA’s 21-tap FIR has coefficients that can be set using remote
commands. The tap weights can be asymmetric to minimize delay through the filter. Extra delay will
reduce the stability of our control loops for sampling phase and automatic gain control.
If the coefficients as entered sum to > 1 they are renormalized to sum to 1.0; if they sum to < 0.1 as
entered they are rejected. Other than that, there are no restrictions on the tap weights.
In many channel chips, the FIR equalization filter is adaptive. However, the DDA does not change
the values set by the user.
Phase Locked Loop (PLL)
Correct operation of any PRML system also depends on the taking of readback signal samples at
exact "focus" positions. Shifting the clock slightly from the correct position is enough to distort
sample values.
A clock recovery circuit, Phase Locked Loop (PLL), adjusts the phase of the oscillator, based on the
value of the phase error. This is usually done in a feedback circuit.
The phase-error function is calculated in the phase detector circuit and is equal to zero in the
correct clock position. When the signal is correct, the error signal is equal to zero, and oscillator
frequency and phase remain in exactly the correct position. If for some reason the phase of the
input signal and that of the oscillator diverge --- owing to instability of disk rotation or noise, for
example --- the phase-error signal deviates from zero, and the frequency of the oscillator shifts.
Two main problems have to be resolved in the clock recovery circuit. One is the initial fast-phase
acquisition: prior to a reading of the pattern, it is necessary to align the clock to the correct position
of the pattern. The other is tracking --- the following of relatively slow instabilities of the disk
rotational speed. In order to avoid fast, noisy phase shifts, and to provide system stability, the
phase-error signal is integrated by an integrator.
424
WM-OM-E Rev I
X-Stream Operator’s Manual
Automatic Gain Control (AGC)
The phase and gain steering algorithm in the DDA’s channel emulation (AGC) will adjust for
changes in the signal after VCO Synch. Read gate tells us where to start looking at the VCO Synch.
Phase is essentially the timing of when a sample is taken, while gain is the levels that are being
searched for as +1 and -1. Thus, when a sample larger than the ideal value is taken, the level
looked for by the emulation is increased. The screen below shows an example of phase and gain
steering.
To start the AGC, we must find the maximum and minimum levels in the VCO Synch, and then
initialize the levels to be searched. Thus, if the pulses are exactly the desired shape, then 1 and -1
will be where expected, with the other levels symmetrically spaced in between.
Note that the VCO Synch must exist in the acquired head signal, or the channel emulation cannot
be run. The phase and gain steering algorithm in the emulation will adjust for changes in the signal
after VCO Synch, assuming it starts correctly.
WM-OM-E Rev I
425
PLL and AGC
The sample, phase-steering (PLL) and gain adjust (AGC, level computation) work together, one
sample at a time. They are used to compute sampled data for input to the Viterbi detector.
ML Detector
Samples on the output of the ADC ideally have a small number of levels: {1,0,+1} for the PR4
system, for example. A threshold detector could be used to classify a current sample value
comparing it to an amplitude threshold. For example, if sample > 0.5, sample = 1; if sample < 0.5,
sample = 1; if sample 0.5, sample = 0.
For the sequence of samples 0.8 0.3 -0.7 -0.2 0.6 0.9 1.1 0.2, the threshold detector output would
be: 1 0 -1 0 1 1 1 0.
The difficulty here is that the sequence of three ones in a row ("111") is impossible: the pulse is too
wide. The only possible combinations are 011, 110, -111, and so on.
A threshold detector, such as the peak detector on a Peak- Detect drive, does not use the previous
and subsequent samples. But the maximum likelihood (ML) detector "knows" that "111" is a
forbidden sequence of samples and tries to determine the most probable data pattern for this
sequence of samples (21 samples used for PR4).
Proposing several close allowable sequences --- {1 0 -1 0 1 1 0 0} or {1 0 -1 0 0 1 1 0} or {1 0 -1 0 0
0 1 1} --- is easy. But which is the most probable?
The decision is made based on a sequence of samples, instead of only a single, current sample,
and the sequence with the minimum distance (maximum likelihood) is selected as the detection
result.
Viterbi Detector & Trellis
The Viterbi detector is a state machine consisting of two distinct parts: states and transitions. While
state is the current magnetization of the disk and some history (memorization of the latest states),
transition relates the current state to the next state. For the detector, only two possibilities exist:
either the state (medium magnetization) is the same between the current and the next bit periods or
it is not.
The detector’s trellis works according to this dichotomy: "0" or "1" is followed by either "0" or "1",
and so on. The trellis is a mechanism that keeps track of a sequence of magnetization states. When
the ML detector makes decisions, it keeps the states of several consecutive time instants and
estimates the likelihood of possible "histories" (higher probability). The higher the order of the
PRML system, the larger and more complex the trellis. However, some trellises do not allow certain
transitions (d=1 constraint), thereby limiting the extent to which the pulses can overlap.
SAM
Sequenced Amplitude Margin (SAM) measures the error margin of every sample taken by a PRML
channel chip. Determining that a written bit is either a "0" or a "1" is the disk drive’s most basic
decision. SAM measures the margin by which the Viterbi detector has made this decision, the
margin or distance being a function of the path metrics and current sample taken together.
SAM can provide a prediction of the error rate, and can be used both for characterization and for
426
WM-OM-E Rev I
X-Stream Operator’s Manual
optimizing equalization. Lower SAM values mean worse error rates.
The range of SAM values depends on the PRML order, as does the path metrics, memory, or
sequence. The range is 0 to 2.0 for a PR4 channel. The "0" in this case signifies that the drive had
no margin to make the decision, that it could have read every single bit wrongly, and that at 2.0 the
drive had as much margin as it could and will never make an error.
The distribution of SAM values will always center on the square of the minimum distance to an error,
i.e., 2.0 for PR4; 1.0 for EPR4 (these numbers are correct when the signal amplitude is normalized,
so sample values are -1 to +1). The width of the distribution is narrow for clean signals, broader for
noisy signals. Misequalized signals have broad, multi-peaked distributions. When the tail of this
distribution crosses zero, it means an error has been made. This can only be determined with
certainty if the correct decode (the correct path through the trellis) is known.
Encoding
Both Peak-Detect and PRML read channels use Run-Length Limited (RLL) coding. This
corresponds to the only part of the channel chip that the DDA does not simulate: that between the
Viterbi detector and the NRZ lines at the output of the chip.
RLL codes impose constraints on the data written to the disk by limiting the minimum and maximum
number of 0's that must come between each pair of 1's in the encoded pattern written to the disk
(head/analog signal). The limitation on the minimum number of "0"s provides transition separation
to avoid pulse crowding. RLL codes are characterized by four parameters, referenced as
(m/n)(d/k):
y
modulation code maps m user bits (NRZ data) into n encoded bits (head/analog signal)
y
n is always bigger than m, because n smaller than m would mean data is compressed on
the disk; Code Rate = m/n
y
d equals the minimum number of 0's between two consecutive 1's
y
k equals the maximum number of 0's between two 1's
The DDA does not implement interleaved ML detection, therefore it does not check even and odd
sample streams separately for this limit. However, when the constraints are specified as (d, k1, k2),
one can sum k1 and k2 and use that where k is needed. This allows a series of non-transitions long
enough to unquestionably be an error to be reported as an error. However, it will not catch all the
sequences that would be an RLL violation for interleaved detection.
Error Correction
Prior to the RLL encoding, the user data is normally encoded inside the drive’s microcontroller,
using special error-correction codes (ECC). Thus, there are two levels of encoding.
User Defined Trellis
File Format and Language (version 1)
This feature allows you to define the trellis used by the Viterbi detector in the LeCroy DDA's channel
emulation. The file specifies the target levels and all possible transitions. You can also specify
many significant aspects of our emulated channel, including the proportional (phase) and integral
(period) gain on the clock steering control loop, the AGC gain, adjustment limits, etc. This permits
WM-OM-E Rev I
427
you to define how the signal will be handled by the emulated channel, as well as the trellis used in
the Viterbi detector.
The User Definition file is a plain ASCII text file. Such a file can be made with Windows Notepad or
any text editor, or by any word processor with a "Save As Text" capability. The file may have any
name in 8.3 format (i.e., DOS file name). Our example uses the extension ".UDF", but it is not
required. A User Definition file can be loaded from floppy disk or hard disk (the hard disk is
optional).
The first characters in the file must be USER DEFINED VITERBI TRELLIS FOR LECROY DDA. If
the string USER DEFINED VITERBI TRELLIS FOR LECROY DDA is not seen at the start of the
file, the file is not parsed, and any previously loaded user definition is left undisturbed. The
message "Header not found at start of file - read aborted" is displayed.
The rest of this Help file defines the keywords that can appear and the arguments they take. An
example file follows. In all cases, if an argument is outside limits, or a stated order dependency is
violated, an informative error message is displayed and the parse is canceled. The error message
will persist on the screen until replaced. If a user definition is successfully loaded, a confirming
message is displayed. The message disappears after approximately 10 seconds.
Loading Your UDT File Remotely
To call the UDT file when operating the instrument remotely, use remote command
DD_LOAD_UDF "filename"
where:
filename = full qualified path to the UDT file, for example, "C:\Lecroy\myudf"
General Rules and Error Messages
All lexical elements should be separated by white space. Lexical elements include keywords and
their arguments. White space includes space, tab, carriage return, and line feed. One exception:
the double slash //, which starts a comment, need not be followed by white space.
As the file is parsed, if the expected number of arguments for a keyword is not available, the error
message "Could not read args for '<keyword>..! abort" will be displayed and the parse is canceled.
If the word where we expect a keyword is not recognized as a keyword, the error message "Word
starting '<text>': not a keyword! Abort" is displayed and the parse is canceled. Possible causes for
this are comment text without a preceding //, or too many arguments for the preceding keyword.
When the end of the file is reached, the DDA verifies that all required keywords were seen in the file.
If not, the message "Missing <number> required keywords!" is displayed and the parse is
considered canceled. Not all keywords are required; however, we strongly encourage you to use
them all, in every file. The result of omitting most optional keywords is to leave previously set values
unchanged.
428
WM-OM-E Rev I
X-Stream Operator’s Manual
Keywords
keyword: //
arguments: none
required?: no
Notes:
1. // begins a comment. After // the rest of the line, up to line feed, is ignored.
2. // need not be followed by a space.
keyword: AGC_GAIN
arguments: <value, 0 to 0.125>
required?: no
Notes:
The difference of the normalized (-1 to +1) sample value to the expected sample value is multiplied
by this to determine the change in expected level. The DDA treats positive and negative levels
separately, to handle asymmetric waveforms. The change in the 0 level is 1/4 of this, a correction to
the 0 level shifts all the levels. The DDA also allows very slow changes of relative spacing; it starts
analyzing each VCO sync field assuming symmetry and perfect spacing. In the DDA, this value is
0.12 for PR4, EPR4, and E2PR4. If this keyword is not seen, its value remains unchanged. If this
value is never set, the default is 0.12.
possible error "AGC_GAIN must be >= 0 and <= 0.125"
messages:
keyword: KEYWORDS_VERSION
arguments: 1
required?: yes
possible error "Keywords version is newer than software rev!" When the keywords file is
messages: updated, this message will specify KEYWORDS_VERSION 2. New software will
be able to handle versions 1 and 2. Old software will produce this error message
if it encounters KEYWORDS_VERSION 2.
keyword: LEVELS
arguments: <number from 3 to 32>
required?: yes
Note:
LEVELS must appear before NORMALIZED_LEVELS are specified
possible error "#levels must be >= 3 and <= 32!"
messages:
WM-OM-E Rev I
429
keyword: MAX_LEVEL_ADJ
arguments: <value from 0.0 to 1.0>
required?: no
Notes:
This sets a hard limit on the maximum change in an expected level due to steering from one sample.
Setting this value to 1.0, or near that value, makes the limit irrelevant. The DDA uses 0.0625 for PR4,
0.03125 for EPR4, and 0.020833 for E2PR4. If this keyword is not seen, its value remains
unchanged. If this value is never set, the default is 0.020833.
possible error "MAX_LEVEL_ADJ must be >= 0 and <= 1.0"
messages:
keyword: MAX_PHASE_ADJ
arguments: <value 0 to 0.1>
required?: no
Notes:
This sets a hard limit on the maximum phase change (and the maximum period change) of the
emulated PLL due to steering from one sample. The value is a fraction of a bit cell time. The DDA
uses 0.06 for PR4 and EPR4, and 0.04 for E2PR4. If this keyword is not seen, its value remains
unchanged. If this value is never set, the default is 0.04.
possible error "MAX_PHASE_ADJ must be >=0 and <=0.1 (bit cells)"
messages:
keyword: NORMALIZED_LEVELS
arguments: (see note below)
required?: no
Notes:
1. This keyword takes LEVELS arguments, each a value from -1 to 1, in order.
2. If this keyword is not supplied, levels default to LEVELS: equally spaced values from -1 to 1.
3. LEVELS must be seen before this keyword.
possible error "Must set #levels before specifying levels!"
messages:
"Must set TOP_LEVEL... before specifying levels!"
"Normalized levels must be in order, -1 to 1!"
"Normalized levels must be -1 to 1!"- arguments didn't include -1 or 1, or both
430
WM-OM-E Rev I
X-Stream Operator’s Manual
keyword: PLL_INTEG_GAIN
arguments: <value 0 to 1e-10>
required?: no
Notes:
The value is multiplied by a code difference from the expected level times slope. The result is to
produce a period correction as a fraction of bit cell time. The DDA uses 4e-11 for PR4, EPR4 and
E2PR4. If this keyword is not seen its value remains unchanged. If it has never been set since power
on the default is 4e-11. See notes for PLL_PROP_GAIN above.
possible error "PLL_INTEG_GAIN must be >= 0 and <= 1e-10"
messages:
keyword: PLL_PROP_GAIN
arguments: <value 0 to 1e-8>
required?: no
Notes:
The value is multiplied by a code difference from the expected level times slope normalized to
codes/bit cell near the sample. The result is to produce a phase correction as a fraction of a bit cell
time. The phase error tends to have a significant random component so this value should be kept low.
The DDA uses 5e-9 for PR4, 2e-9 for EPR4 and 1e-9 for E2PR4. If this keyword is not seen, its value
remains unchanged. If it has never been set since power on, the default is 1e-9.
Notes about the PLL loop:
We steer our software PLLs phase (proportional) and period (integral) with coefficients
phase_steering_gain and spacing_steering_gain. They are used like this:
spacing correction = phase error * spacing_steering_gain
phase correction = phase error * phase_steering_gain
where:
phase error = distance from sample to level * slope * scope samples per bit cell
Notes:
1. Distance is normalized (-7200 = -1 level, +7200 = +1 level)
2. Slope is (normalized codes/scope sample) around the channel sample position
3. Multiplying by samples per bit cell normalizes for scope sample rate: slope
(codes/scope sample) is cut in half when sample rate doubles
codes/scope sample * scope sample/bit cell = codes/bit cell
The gain terms must be small enough so that the correction is mostly uncompleted within the latency
(STEERING_LATENCY + FIR delay) of the control loop. Otherwise the loop will be unstable.
The spacing and phase corrections are in fractions of a bit cell.
possible error "PLL_PROP_GAIN must be >= 0 and <= 1e-8"
messages:
WM-OM-E Rev I
431
keyword: STATE
arguments: <which state> 0 to STATES minus 1
<previous state from 0> 0 to STATES minus 1 (or 100, see below)
<expected sample level from 0> -1 to 1
<previous state from 1> 0 to STATES minus 1 (or 100, see below)
<expected sample level from 1> -1 to 1
required?: yes
Notes:
1. The states are specified in NRZ (nonreturn to zero) format, that is 0 and 1 are the two polarities of
magnetization. On the head signal (the first sample of) a negative going pulse begins a "0" polarity
region on the media, and a positive going pulse begins a "1" polarity region. "from 0" means the bit
cell which is no longer part of the state was 0 polarity. Consider the state 0011. If the preceding state
was 0001 then the state 0011 was arrived at along the "from 0" transition. Similarly if the preceding
state was 1001 then the state 0011 was arrived at along the "from 1" transition.
2. At least one STATE specification must be seen or the parse is considered failed.
3. In some cases one (or both) of the transitions to a state may not be valid, that is, they are
disallowed due to encoding constraints. In such a case use the value 100 as the "previous state from"
for that transition, this is recognized as disallowing the transition. Any other value outside of 0 to
STATES minus one is declared a parse error. If both transitions to a state are disallowed, the state
cannot be arrived at; it is invalid. You need not specify invalid states (states that cannot be arrived at).
For proper operation you must specify every state that can be arrived at.
4. The STATES keyword, specifying the number of states, must be seen before a STATE can be
specified.
possible error "Must set #states before STATE info!" - see note 4 above.
messages:
"State <number>?? Expected states 0 to <STATES - 1>!"
"State <number>: must be -1 < expected level < 1!"
keyword: STATES
arguments: <number from 4 to 16>
required?: yes
Note:
STATES must appear before a STATE is specified
possible error "#states must be >= 4 and <= 16!"
messages:
432
WM-OM-E Rev I
X-Stream Operator’s Manual
keyword: STEERING_LATENCY
arguments: <value 0 to 10>
required?: no
Notes:
The DDA's channel emulation uses decision directed steering. This means that the PLL and AGC are
not determined based on the nearest level to each sample. Instead, we wait STEERING_LATENCY
samples and then steer based on what the sample should have been according to the Viterbi
detector. The DDA uses 6 for PR4, EPR4, and E2PR4. After 6 samples it is far more likely that the
detector has already picked the correct path, and we will steer toward the correct target. If this
keyword is not seen, its value remains unchanged. If it has never been set since power on, the default
is 6. CAUTION: Increasing the steering latency increases the delay for the steering control loops and
may make them unstable. For a 16 state signal (such as E2PR4), the detector uses the sample at
STEERING_LATENCY into the trellis, and four more preceding it (that is, further into the trellis) to
determine the expected value for the sample at STEERING_LATENCY. The difference between the
actual sample value and the expected value determines steering.
possible error "STEERING_LATENCY must be >= 0 and <=10"
messages:
keyword: TOP_LEVEL_AS_FRACTION_OF_PEAK
arguments: <number, 0.5 to 1.5>
required?: yes
Notes:
This is the ratio of the nominal "1" sample level to the peak height of the VCO sync pattern. This is
used in our emulated channel's acquisition of the proper sampling phase and levels. For example,
using a 2T sync pattern, PR4 has levels +1, +1, -1, -1 & and the peaks are significantly higher. For
PR4, the DDA uses 0.7854 for this value. For EPR4, a 2T pattern is 0, +1, 0, -1& so the peaks are +1
and -1. For EPR4 the DDA uses 1.0000 for this value. For E2PR4 a 2T pattern is +0.6667, +0.6667,
-0.6667, -0.6667, and the peaks are higher, slightly above the +1 level. For E2PR4 the DDA uses
1.06045 for this value.
possible error "top level must be > 0.5 and <= 1.50 x sync peak"
messages:
keyword: TRELLIS_LENGTH
arguments: <value 11 to 81>
required?: no
Notes:
Because of internal implementation constraints, the trellis cannot be 28 to 32 long, or 60 to 64 long.
An attempt to set it within those ranges will be accepted but will actually set the next larger permitted
value, that is, 33 or 65. If this keyword is not seen its value remains unchanged. If this value is never
set the default is 81. Longer trellis size does not noticeably slow down processing. Longer trellis size
approaches true maximum likelihood to greater certainty. Real disk channels tend to have short
trellises and rely on encoding to avoid sequences that would require a longer trellis to resolve. On a
good signal all possible paths being maintained in the trellis are the same beyond a few bits in, the
vast majority of the time.
WM-OM-E Rev I
433
possible error "TRELLIS_LENGTH must be >= 11 and <= 81"
messages:
keyword: ZERO_CROSS_TO_SAMPLE
arguments: <value 0 to 0.5>
required?: yes
Notes:
This tells the DDA how the correct sampling times relate to zero crossings during the VCO
synchronization preamble. The value is a fraction of the spacing between zero crossings. Example:
The VCO synch is normally a 2T pattern. For PR4 the samples are 1, 1, -1, -1; there are two samples
between zero crossings, and the first sample after a zero crossing is one quarter of the distance to the
next zero crossing. Therefore ZERO_CROSS_TO_SAMPLE is 0.25 for PR4. For EPR4, a 2T pattern
gives samples 0,1,0,-1; the first sample is at the zero crossing; therefore,
ZERO_CROSS_TO_SAMPLE is 0 for EPR4. For E2PR4, a 2T pattern gives 2/3, 2/3, -2/3, -2/3; there
are two samples between zero crossings, and the first sample after a zero crossing is one quarter of
the distance to the next zero cross, just as for PR4. Therefore ZERO_CROSS_TO_SAMPLE is 0.25
for E2PR4.
possible error "ZERO_CROSS_TO_SAMPLE must be >= 0 and <= 0.5"
messages:
Example File
An example of a user definition equivalent to E2PR4 (d=0) follows. This file was named
E2PR4.UDF:
USER DEFINED VITERBI TRELLIS FOR LECROY DDA // a comment can go here
// The above line is required exactly as shown or the file will be rejected!
KEYWORDS_VERSION 1
STATES 16
// State initializers - one for each valid state
// state prev from 0 level prev from 1 level
STATE 0 0 0 8 -0.33333
STATE 1 0
0.33333 8 0
STATE 2 1
0.66667 9 0.33333
STATE 3 1 1 9 0.66667
STATE 4 2 0 10 -0.33333
STATE 5 2
0.33333 10
0
STATE 6 3
0.66667 11
0.33333
STATE
434
7 3 1 11
0.66667
WM-OM-E Rev I
X-Stream Operator’s Manual
STATE
8 4
-0.66667 12
-1
STATE
9 4
-0.33333 12
-0.66667
STATE 10 5
STATE
11 5
0 13
-0.33333
0.33333 13
0
STATE 12 6
-0.66667 14
-1
STATE 13 6
-0.33333 14
-0.66667
STATE 14 7
0 15
STATE 15 7
0.33333 15
-0.33333
0
LEVELS 7
TOP_LEVEL_AS_FRACTION_OF_PEAK 1.06045 // nominal 1 / peak height in vco sync
field. For 2T
NORMALIZED_LEVELS -1 -.66667 -.33333 0 .33333 .66667 1
PLL_PROP_GAIN 1e-9
PLL_INTEG_GAIN 4e-11
MAX_PHASE_ADJ 0.04
STEERING_LATENCY 6
TRELLIS_LENGTH 81
AGC_GAIN 0.12
MAX_LEVEL_ADJ 20.833e-3
ZERO_CROSS_TO_SAMPLE 0.25
// Fraction of zero cross spacing
// End of file
§§§
WM-OM-E Rev I
435
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF

advertising