xx
SPECMONB Series
ZZZ
Real-Time Spectrum Analyzers
Printable Help
*P077090500*
077-0905-00
SPECMONB Series
Real-Time Spectrum Analyzers
ZZZ
Printable Help
www.tektronix.com
077-0905-00
Copyright © Tektronix. All rights reserved. Licensed software products are owned by Tektronix or its
subsidiaries or suppliers, and are protected by national copyright laws and international treaty provisions.
Tektronix products are covered by U.S. and foreign patents, issued and pending. Information in this
publication supersedes that in all previously published material. Specifications and price change privileges
reserved.
TEKTRONIX and TEK are registered trademarks of Tektronix, Inc.
Product help part number: 076-0340-00
Contactin
g Tektronix
Tektronix, Inc.
14150 SW Karl Braun Drive
P. O . B o x 5 0 0
Beaverton, OR 97077
USA
For product information, sales, service, and technical support:
In North America, call 1-800-833-9200.
Worldwide, visit www.tektronix.com to find contacts in your area.
Table of Contents
Welcome
Welcome............................................................................................................. 1
About Tektronix Analyzer
Product Software .... ................................ .................................. ............................. 3
Accessories
Standard Accessories.......................................................................................... 3
Options
Options.......................................................................................................... 5
Documentation and Support
Documentation ................................................................................................. 5
Video Tutorials................ .................................. ................................ ............... 6
Orientation
Front Panel Connectors ....... ................................ .................................. ................... 9
Front-Panel Controls ...................................... ................................ ......................... 9
Touch Screen............................. ................................ .................................. ........ 13
Touch-Screen Actions............................................................................................. 13
Elements of the Display........................................................................................... 15
Rear-Panel Connectors.............. ................................ .................................. ............ 19
Setting Up Network Connections . .... . .... .... . .... . .... . .... ..... .... . .... . .... ... . . .... . .... . .... ..... .... . ... 19
Table of Contents
Operating Your Instrument
Restoring Default Settings.............. .................................. ................................ ........ 21
Running Alignments ................................ ................................ .............................. 21
Presets................................. ................................ ................................ .............. 22
Setting Options. ... . . .... . .... . .... . .... .... . .... . .... . .... . .... .... . .... . .... . .... . .... .... . .... . .... . .... . .... .... 28
Operating System Restore ........................................................................................ 31
Using the Measurement Displays
Selecting Displays. ................................ ................................ ................................ 33
Taking Measurements
Measurements
Available Measurements... ................................ ................................ .................. 35
General Signal Viewing
Overview ........................................................................................................... 43
SPECMONB Series Printable Help i
Table of Contents
DPX
DPX Primer ............................. .................................. ................................ .... 43
DPX Display Overview ........................ ................................ .............................. 65
DPX Display .................. ................................ .................................. .............. 65
DPX Settings ... . .... ..... ... . . .... . .... . .... ..... ..... .... . .... . .... . .... . .... ..... ... . . .... . .... . .... ..... ... 73
Time Overview
Time Overview Display...................................................................................... 88
Time Overview Settings ..................................................................................... 90
Spectrum
Spectrum Display............... ................................ ................................ .............. 93
Spectrum Settings.. ... . . .... . .... .... . .... . .... .... . .... . .... ... . . .... . .... .... . .... . .... ... . . .... . .... .... . .. 95
Spectrogram
Spectrogram Display ................... ................................ ................................ ...... 96
Spectrogram Settings . .... . .... . .... ... . . .... . .... . .... ... . . .... . .... ..... .... . .... . .... ... . . .... . .... ..... ... 99
Amplitude Vs Time
Amplitude Vs Time Display... .................................. ................................ .......... 103
Amplitude Vs Time Settings ................................ ................................ .............. 104
Frequency Vs Time
Frequency Vs Time Display ............................................................................... 105
Frequency Vs Time Settings.. . .... ..... ..... ... . . ... . . .... . .... . .... . .... . .... . .... . .... . .... . .... . .... . .. 106
Phase Vs Time
Phase Vs Time Display..................................................................................... 107
Phase Vs Time Settings ..... ... . . .... . .... . .... .... . .... . .... . .... ..... .... . .... . .... ..... ..... .... . .... . .. 108
RF I & Q Vs Time
RF I & Q vs Time Display................................................................................. 109
RF I & Q vs Time Settings. . .... . .... . .... . .... . .... . .... . .... . .... . .... . .... . .... . .... . .... . .... ..... . .... 110
Common Controls for General Signal Viewing Displays
General Signal Viewing Shared Measurement Settings . .... . .... . .... ..... .... . .... . .... .... . .... . .... 111
Analog Modulation
Overview ......................................................................................................... 123
AM
AM Display ..... .................................. ................................ .......................... 123
AM Settings ................................................................................................. 124
FM
FM Display.................................................................................................. 129
FM Settings.. . .... ..... .... . .... . .... ..... ... . . .... . .... . .... .... . .... . .... . .... . .... .... . .... . .... . .... ..... 131
PM
PM Display.................................................................................................. 137
PM Settings.. . .... ..... .... . .... . .... ..... ... . . .... . .... . .... .... . .... . .... . .... . .... .... . .... . .... . .... ..... 139
ii SPECMONB Series Printable Help
RF Measurements
Overview ......................................................................................................... 147
Channel Power and Strength Display
Channel Power and Strength Display..................................................................... 147
Channel Power & Strength Settings .... ... . . .... . .... ..... .... . .... . .... ..... .... . .... . .... .... . .... . .... 151
MCPR
MCPR (Multiple Carrier Power Ratio) Display . .... . .... . .... .... . .... . .... ... . . .... . .... ... . . .... . .... 154
MCPR Settings.......... ................................ ................................ .................... 157
Occupied BW & x dB BW
Occupied BW & x dB BW Display......................... ................................ .............. 163
Occupied BW & x dB BW Settings ...... .................................. .............................. 166
Spurious
Spurious Display............................................................................................ 167
Spurious Display Settings. .... . .... . .... . .... ..... ..... .... . .... . .... . .... . .... ..... ..... .... . .... . .... . ... 171
CCDF
CCDF Display............................................................................................... 178
CCDF Settings . . .... .... . .... . .... .... . .... . .... .... . .... . .... ... . . .... . .... ... . . .... . .... ... . . .... . .... .... 179
Phase Noise
Phase Noise Display........................................................................................ 180
Phase Noise Settings . . .... . .... ..... ... . . .... . .... . .... . .... . .... ..... ..... .... . .... . .... . .... . .... . .... . .. 185
Settling Time Measurements
Settling Time Measurement Overview ... . .... . .... .... . .... . .... ..... ... . . .... . .... . .... .... . .... . .... .. 187
Settling Time Displays
Settling Time Displays ... . . .... . .... . .... ... . . .... . .... . .... . .... .... . .... . .... . .... . .... .... . .... . .... . ... 191
Settling Time Settings .. . .... . .... ..... ..... .... . .... . .... . .... . .... ..... ..... .... . .... . .... . .... . .... . .... . 199
Common Controls for Settling Time Displays
Settling Time Displays Shared Measurement Settings .... . .... ..... ..... .... . .... . .... ..... ..... .... . . 199
SEM (Spectrum Emission Mask)
SEM Display ................................................................................................ 207
Spectrum Emission Mask Settings .... .... . .... . .... . .... . .... ... . . .... . .... . .... . .... ..... ... . . .... . .... . 210
Common Controls for RF Measurements Displays
RF Measurements Shared Measurement Settings ... . . .... . .... . .... .... . .... . .... . .... ..... .... . .... . .. 217
Table of Contents
WLAN Measurements
WLAN Overview.. ................................ .................................. ............................ 225
WLAN Chan Response
WLAN Channel Response Display......................... ................................ .............. 227
WLAN Channel Response Settings. . .... . .... . .... . .... .... . .... . .... . .... . .... .... . .... . .... . .... ..... .. 229
WLAN Constellation
WLAN Constellation Display ............................................................................. 230
WLAN Constellation Settings............................................................................. 231
WLAN EVM
SPECMONB Series Printable Help iii
Table of Contents
WLAN EVM Display .......... ................................ .................................. .......... 232
WLAN EVM Settings.... .... . .... . .... . .... . .... ..... ..... .... . .... . .... . .... . .... .... . .... . .... . .... . .... 233
WLAN Mag Error
WLAN Magnitude Error Display......................................................................... 234
WLAN Magnitude Error Settings... . .... . .... . .... . .... ... . . .... . .... . .... . .... ..... ..... .... . .... . .... . . 235
WLAN Phase Error
WLAN Phase Error Display............................................................................... 236
WLAN Phase Error Settings. . .... . .... . .... . .... . .... . .... ... . . .... . .... . .... . .... . .... . .... ..... ..... .... 237
WLAN Power vs Time
WLAN Power vs Time Display........................................................................... 238
WLAN Power vs Time Settings........................................................................... 240
WLAN Spectral Flatness
WLAN Spectral Flatness Display....................... ................................ .................. 241
WLAN Spectral Flatness Settings . . .... ..... ..... .... . .... . .... ..... ..... .... . .... . .... ..... ... . . .... . ... 242
WLAN Summary
WLAN Summary Display ................................................................................. 243
WLAN Summary Settings . .... ... . . .... . .... . .... ..... .... . .... . .... ... . . .... . .... . .... ..... .... . .... . .... 247
WLAN Symb Table
WLAN Symbol Table Display .......................... ................................ .................. 248
WLAN Symbol Table Settings ... ... . . .... . .... ..... .... . .... . .... .... . .... . .... . .... ... . . .... . .... . .... .. 250
Common Controls for WLAN A nalysis Displays
WLAN Analysis Shared Measurement Settings ... ..... .... . .... . .... . .... ..... .... . .... . .... . .... ..... 250
OFDM Analysis
Overview ......................................................................................................... 261
OFDM Chan Response
OFDM Channel Response Display ................. .................................. .................... 261
OFDM Channel Response Settings . . .... . .... . .... ..... .... . .... . .... . .... . .... .... . .... . .... . .... . .... .. 263
OFDM Constellation
OFDM Constellation Display ............................................................................. 264
OFDM Constellation Settings............................................................................. 265
OFDM EVM
OFDM EVM Display ........ ................................ ................................ .............. 265
OFDM EVM Settings .... .... . .... . .... ... . . .... . .... ..... ... . . .... . .... ..... .... . .... . .... .... . .... . .... . . 266
OFDM Flatness
OFDM Spectral Flatness Display ............... .................................. ........................ 267
OFDM Spectral Flatness Settings... . .... . .... . .... ..... .... . .... . .... . .... . .... ..... ... . . .... . .... . .... .. 268
OFDM Mag Error
OFDM Magnitude Error Display ......................................................................... 269
OFDM Magnitude Error Settings ......................................................................... 270
OFDM Phase Error
OFDM Phase Error Display ............................................................................... 271
iv SPECMONB Series Printable Help
OFDM Phase Error Settings . . .... . .... . .... . .... . .... . .... ..... . .... ..... ..... .... . .... . .... . .... . .... . ... 272
OFDM Power
OFDM Power Display ..................................................................................... 273
OFDM Power Settings .... . .... ... . . .... . .... . .... . .... .... . .... . .... . .... . .... .... . .... . .... . .... . .... .... 274
OFDM Summary
OFDM Summary Display.................................... ................................ .............. 275
OFDM Summary Settings ................................................................................. 276
OFDM Symb Table
OFDM Symbol Table Display............................................................................. 277
OFDM Symbol Table Settings ...... ................................ ................................ ...... 278
Common Controls for OFDM Analysis Displays
OFDM Analysis Shared Measurement Settings... . .... . .... . .... . .... .... . .... . .... . .... . .... .... . .... . 278
Pulsed RF
Overview ......................................................................................................... 287
Pulse Table Display
Pulse Table Display............................... .................................. ........................ 287
Pulse Table Settings . ... . . .... . .... ..... .... . .... . .... .... . .... . .... ... . . .... . .... ..... .... . .... . .... ... . . .. 288
Pulse Trace Display
Pulse Trace Display......... ................................ .................................. .............. 289
Pulse Trace Settings . . .... . .... . .... . .... . .... . .... . .... ..... ..... ... . . ... . . .... . .... . .... . .... . .... . .... . .. 291
Pulse Statistics
Pulse Statistics
Pulse Statistics Settings .... . .... . .... . .... . .... ..... ..... .... . .... . .... . .... . .... .... . .... . .... . .... . .... .. 293
Common C ontrols for Pulsed RF Displays
Pulsed RF Shared Measurement Settings .................................... ............................ 293
Table of Contents
Display....................................... .................................. ............ 291
Audio Analysis
Overview ......................................................................................................... 305
Audio Spectrum
Audio Spectrum Display................................................................................... 305
Audio Spectrum Settings. .... ... . . .... . .... . .... . .... ..... ..... .... . .... . .... . .... . .... .... . .... . .... . .... . 306
Audio Summary
Audio Summary Display........................................... .................................. ...... 307
Audio Summary Settings . .... . .... . .... . .... ..... ..... .... . .... . .... . .... . .... . .... . .... ..... ..... .... . ... 308
Common Controls for Audio Analysis Displays
Audio Analysis Measurement Settings................................................................... 309
GP Digital Modulation
Overview ......................................................................................................... 319
Constellation
Constellation Display....................................................................................... 320
SPECMONB Series Printable Help v
Table of Contents
Constellation Settings . . .... ..... .... . .... . .... . .... .... . .... . .... ... . . .... . .... ..... ... . . .... . .... ..... .... 321
Demod I & Q vs Time
Demod I & Q vs Time Display............................................................................ 322
Demod I & Q vs Time Settings .... . .... .... . .... . .... . .... . .... .... . .... . .... . .... . .... .... . .... . .... . ... 324
EVM vs Time
EVM vs Time Display........................ ................................ .............................. 324
EVM vs Time Settings ..... .... . .... . .... . .... . .... ..... ..... .... . .... . .... . .... . .... ..... ..... .... . .... . .. 325
Eye Diagram
Eye Diagram Display............................. ................................ .......................... 326
Eye Diagram Settings .......... .................................. ................................ .......... 327
Frequency Deviation vs Time
Frequency Deviation vs Time Display ................................................................... 328
Frequency Deviation vs Time Settings ... . .... . .... . .... . .... ..... ..... .... . .... . .... . .... . .... .... . .... . 330
Magnitude Error vs Time
Magnitude Error vs Time Display ...................................... ................................ .. 330
Magnitude Error vs Time Settings .. .................................. ................................ .... 332
Phase Error vs Time
Phase Error vs Time Display ...... ................................ ................................ ........ 332
Phase Error vs. Time Settings . .... ..... ..... ... . . ..... .... . .... . .... . .... . .... . .... . .... . .... . .... . .... . .. 334
Signal Quality
Signal Quality Display .... . .... .... . .... . .... ..... ... . . .... . .... . .... .... . .... . .... ..... ... . . .... . .... . .... 334
Signal Quality Settings.. . . .... . .... . .... . .... .... . .... . .... . .... . .... .... . .... . .... . .... . .... .... . .... . .... 339
Symbol Table
Symbol Table Display............................ ................................ .......................... 340
Symbol Table Settings.... . .... . .... . .... . .... ..... ..... .... . .... . .... . .... . .... . .... . .... ..... ..... ... . . ... 341
Trellis Diagram
Trellis Diagram Display.. . .... . .... ..... ..... .... . .... . .... . .... ..... .... . .... . .... . .... . .... .... . .... . .... 341
Trellis Diagram Settings . .... .... . .... . .... . .... . .... .... . .... . .... . .... . .... .... . .... . .... . .... . .... .... . . 343
Common Controls for GP Digital Modulation Displays
GP Digital Modulation Shared Measurement Settings ................................................. 343
Standard Settings Button .... . .... . .... ... . . .... . .... ..... .... . .... . .... .... . .... . .... ... . . .... . .... ..... ... 344
Symbol Maps
Symbol Maps.................................. .................................. ............................ 360
User Filters
Overview: User Defined Measurement and Reference Filters... .... . .... . .... ..... ... . . .... . .... . .... 366
User Filter File Format . . .... . .... . .... ..... .... . .... . .... . .... ..... .... . .... . .... . .... ..... .... . .... . .... . . 367
Marker Measurements
Using Markers
Using Markers............................................................................................... 371
Controlling Markers with the Touchscreen Actions Menu... . .... . .... ... . . .... . .... . .... ..... .... . ... 371
Measuring Signal Density, Frequency and Power on a DPX Bitmap Trace.......................... 373
vi SPECMONB Series Printable Help
Measuring Frequency and Power in the Spectrum Display .............. .............................. 374
Common Marker Actions
Marker Action Controls............................................................................... 375
Peak.. ................................ .................................. ................................ .. 375
Next Peak ............................................................................................... 375
Marker to Center Frequency.......................................................................... 375
Define Markers Control Panel
Enabling Markers and Setting Marker Properties . .... . .... . .... . .... ... . . .... . .... . .... . .... ... . . . 375
Markers Toolbar
Using the Markers Toolbar.. ................................ .................................. ........ 377
Noise Markers in the Spectrum Display
Using Noise Markers in the Spectrum Display............. .................................. ...... 378
Search (Limits Testing)
The Search Tool (Limits Testing).... ................................ .................................. ........ 381
Search (Limits Testing) Settings ............................................................................... 381
Define Tab (Search) ................. ................................ .................................. .......... 381
Actions Tab....................... .................................. ................................ .............. 385
Table of Contents
Analyzing Data
Analysis Settings
Analysis Settings.............................. ................................ .............................. 387
Analysis Time Tab
Spectrum Time Tab....................... ................................ .................................. 389
Frequency Tab............................................................................................... 389
Units Tab............................. ................................ .................................. ...... 393
Analyzing Data Using Replay
Replay Overview ........................................................................................... 393
Replay Menu ...... ................................ .................................. ........................ 396
Acq Data................... .................................. ................................ ................ 396
DPX Spectra................................................................................................. 396
Replay All Selected Records ............ ................................ .................................. 397
Replay Current Record..................................................................................... 397
Replay from Selected....................................... ................................ ................ 397
Pause ............................. .................................. ................................ .......... 397
Stop........................................................................................................... 397
Select All .................................................................................................... 397
Select Records from History............................................................................... 398
Replay Toolbar.............................................................................................. 398
........................ ................................ ................................ .. 387
Amplitude Corrections
Amplitude Settings . .... . .... . .... . .... ..... ..... .... . .... . .... . .... . .... ..... ..... .... . .... . .... . .... . .... ..... . 401
SPECMONB Series Printable Help vii
Table of Contents
Internal Settings Tab . . .... ..... ..... .... . .... . .... . .... . .... . .... . .... ..... ..... .... . .... . .... . .... . .... ..... ... 401
External Gain/Loss Correction Tab.................................... ................................ ........ 404
External Gain Value ........................................................................................ 405
Apply External Corrections To................................ ................................ ............ 405
External Loss Tables ....................................................................................... 406
External Probe Correction Tab ................................................................................. 408
Controlling the Acquisition of Data
Acquisition Controls in the Run Menu
Continuous Versus Single Sequence............ ................................ .......................... 409
Run ................................. ................................ .................................. ........ 409
Resume....................................................................................................... 409
Abort ............................. .................................. ................................ .......... 409
Acquisition Controls in the Acquire Control Panel
The Acquire Control Panel ...... ................................ .................................. ........ 410
Sampling Parameters Tab............ .................................. ................................ .... 411
Advanced Tab (Acquire)................................................................................... 412
FastSave ..................................................................................................... 413
FastSave Tab ................................................................................................ 416
UsingTriggerstoCaptureJustWhatYouWant
Triggering
Triggering............................................................................................... 416
Frequency Mask Tr
Mask Editor (Frequency Mask Trigger)............................. ................................ 420
Trigger Settings .... .... . .... . .... .... . .... . .... ... . . .... . .... ... . . .... . .... ... . . .... . .... ... . . .... . .... 423
Event Tab ............................................................................................... 424
Time Qualified Tab .................................................................................... 433
Advanced Tab (Triggering) . .................................. ................................ ........ 434
Actions Tab (Triggering) .............................................................................. 435
igger .............................................................................. 420
Managing Data, Settings, and Pictures
Saving and Recalling Data, Settings, and Pictures... ..... ..... .... . .... . .... . .... . .... . .... . .... ..... ..... .. 437
Data, Settings, and Picture File Formats ... . .... .... . .... . .... .... . .... . .... ..... .... . .... . .... ..... .... . .... . 439
Printing Screen Shots ........................................................................................... 443
Reference
Online Help ...................................................................................................... 445
About the Tektronix RTSA..................................................................................... 445
Connecting Signals
Configure In/Out Settings .... . .... . .... .... . .... . .... .... . .... . .... .... . .... . .... .... . .... . .... .... . .... . .. 446
Connecting an RF Signal .................................................................................. 446
Connecting a Signal Using a TekConnect Probe.... ................................ .................... 448
viii SPECMONB Series Printable Help
Table of Contents
Connecting External Trigger Signals ....... .................................. ............................ 448
Digital I and Q Outputs .................................................................................... 449
Other Outputs ............................................................................................... 450
Zero Span........................ .................................. ................................ .......... 450
Mapping Measurements
Mapping Measurements.................................................................................... 452
Menus
Menu Overview............................................................................................. 452
File Menu
File Menu ............................................................................................... 453
View Menu
View Menu ............................................................................................. 457
Run Menu
Run Menu................................... ................................ ............................ 458
Replay
Replay Menu ........................................................................................... 460
Markers Menu
Markers Menu .......................................................................................... 460
Setup Menu
Setup Menu........... ................................ .................................. ................ 460
Presets Menu
Presets Menu . ................................ ................................ .......................... 460
Tools Me nu
Tools Menu ..................... .................................. ................................ ...... 461
Window Menu
Window Menu................ .................................. ................................ ........ 463
Help Menu
Help Menu.................... ................................ ................................ .......... 463
Troubleshooting
Error and Information Messages .......................................................................... 464
Displaying the Windows Event Viewer .................................................................. 472
Dealing with Sluggish Instrument Operation ............................................................ 474
On/Standby Switch
On/Standby Switch . .................................. ................................ ...................... 474
Upgrading the Product Software
How to Find Out if Software Upgrades are Available.................................................. 474
Changing Settings
Settings. .... . .... . .... . .... . .... . ..... .... . ..... ... . . ..... ..... ..... ..... ..... ..... ..... ..... . .... ..... . .... .. 474
Remote Login
Remote Login ............. ................................ .................................. ................ 476
SPECMONB Series Printable Help ix
Table of Contents
Glossary
Index
x SPECMONB Series Printable Help
Welc ome Welc ome
Welcome
This help provides in-depth information on how to use the SPECMONB Series Real-Time Spectrum
Analyzers. This help contains the most complete descriptions of how to use the analyzer. For a shorter
introductio
Start User Manual. To see tutorial examples of how to use your analyzer to take measurements in different
application areas, refer to the SPECMONB Series Real Time Spectrum Analyzer Application Examples
Reference.
n to the Signal Analyzer, refer to the SPECMONB Series Real-Time Signal Analyzer Quick
SPECMONB Series Printable Help 1
Welc ome Welcome
2 SPECMONB Series Printable Help
About Tektronix Analyzer Product Software
Product Software
The instrument includes the following software:
SPECMONB Series System Software: The SPECMONB Series product software runs on a specially
configured version of Windows 7. As with standard Windows 7 installations, you can install other
compatible applications, but the installation and use of non-Tektronix software is not supported by
Tektronix.
Operating System chapter in the SPECMONB Series Real-Time Spectrum Analyzer Quick Start User
Manual (Tektronix part number 071-3229-XX, English). The operating system restore procedure is
also provided in Operating System Restore
that is not specifically provided by Tektronix for use with your instrument.
Product Software: The product software is the instrument application. It provides the user interface
(UI) and all other instrument control functions. You can minimize or even exit/restart the instrument
application as your needs dictate.
Occasionally new versions of software for your instrument may become available at our Web site. Visit
www.tektronix.com/software
If you need to reinstall the operating system, follow the procedure in the Restoring the
(see page 31). Do not substitute any version of Windows
for information.
Software and Hardware Upgrades
onix may offer software or hardware upgrade kits for this instrument. Contact your local Tektronix
Tektr
distributor or sales o ffice for more information.
Standard Accessories
The standard accessories for the instruments are shown below. For the latest information on available
essories, see the Tektronix Web site
acc
Quick Start User Manual
English - Option L0, Tektronix part number 071-3229-XX
panese - Option L5, Tektronix part number 071-3230-XX
Ja
Simplified Chinese - Option L7, Tektronix part number 071-3231-XX
Russian, Option L10, Tektronix part number 071-3232-XX
Applications Instructions
.
English – Tektronix part number 071-3287-XX
Japanese - Option L5, Tektronix part number 071-3288-XX
SPECMONB Series Printable Help 3
About Tektronix Analyzer Standard Accessories
Simplified Chinese - Option L7, Tektronix part number 071-3289-XX
Russian, Option L10, Tektronix part number 071-3290-XX
Product Documentation CD-ROM
The Product Documentation CD-ROM contains a collection documentation available for your product, in
PDF format. Following is a partial list of the types of documents included on the CD-ROM.
SPECMONB Series Real-Time Spectrum Analyzer Declassification and Security Instructions manual
PDF, Tektronix part number 077-0908-XX
SPECMONB Series Real-Time Spectrum Analyzer Programmer Manual PDF, Tektronix part number
077-0907-XX
SPECMONB Series Real-Time Spectrum Analyzer Specifications and Performance Verification PDF,
Tektronix part number 077-0906-XX
Other related materials
NOTE. To check for updates to the instrument documentation, browse to www.tektronix.com/manuals
and sea
rch by your instrument's model number.
Important Documents Folder
Certificate of Calibration documenting NIST traceability, 2540-1 compliance, and ISO9001 registration
Power Cords
North America - Option A0, Tektronix part number 161-0104-00
Universal Euro - Option A1, Tektronix part number 161-0104-06
ited Kingdom - Option A2, Tektronix part number 161-0104-07
Un
Australia - Option A3, Tektronix part number 161-0104-05
240V North America - Option A4, Tektronix part number 161-0104-08
Switzerland - Option A5, Tektronix part number 161-0167-00
Japan - Option A6, Tektronix part number 161-A005-00
China - Option A10, Tektronix part number 161-0306-00
India - Option A11, Tektronix part number 161-0324-00
No power cord or AC adapter - Option A99
4 SPECMONB Series Printable Help
About Tektronix Analyzer Options
Optical Wheel Mouse
Options
To view a listing of the software options installed on your instrument, select Help > About Your
Tektronix Real-Time Analyzer. There is a label on the rear-panel of the instrument that lists installed
hardware options.
Options can be added to your instrument. For the latest information on available option upgrades, see
Tektronix Web site
.
Documentation
In addition to the instrument help, the following documents are available. Many documents are provided
on the documentation CD provided with the instrument. For the most up to date documentation, visit the
Tektronix website www.Tektronix.com/downloads
Quick Start User Manual (071-3229-XX - English). This manual has information about installing
and operating your instrument. The manual is also available in Japanese (071-3230-XX), Simplified
Chines
aprintablePDFfile.
e (071-3231-XX), and Russian (071-3232-XX). These manuals are available in both print and
.
cation Examples Reference (071-3287-XX). This manual provides examples of how to solve
Appli
problems using a SPECMONB Series Signal Analyzer. This manual is also available in Japanese
(071-3288-XX), Simplified Chinese (071-3289-XX), and Russian (071-3290-XX). These manuals are
available in both p rint and a printable PDF file.
Programmer Manual (077-0907-XX). This m anual provides information to use commands for
remotely controlling your instrument. This is available as a printable PDF file.
Service Manual (077-0909-XX). This manual includes procedures to service the instrument to the
module level. This is available as a printable PDF file.
Specifications and Performance Verification Technical Reference Manual (077-0906-XX). This
manual includes both the specifications and the performance verification procedures. This is available
asaprintablePDFfile.
Declassification and Security Instructions (077-0908-XX). This document helps customers with
data security concerns to sanitize or remove memory devices from the instrument. This is available as
aprintablePDFfile.
The most recent versions of the product documentation, in PDF format, can be downloaded from
www.tektronix.com/manuals
. You can find the manuals by searching on the product name.
Other Documentation
Your instrument includes supplemental information on CD-ROM:
SPECMONB Series Printable Help 5
About Tektronix Analyzer Video Tutorials
Documents CD (Tektronix part number 063-4515-XX)
Video Tutorials
You can browse the Tektronix YouTube channel (www.youtube.com/user/tektronix) to find video tutorials
about various topics related to your product. You can also subscribe to the Tektronix YouTube ch
keep up with new postings.
Searching for topics
For example, you can watch a video tutorial about using the WLAN Presets. To find a video on this topic,
do the following. The following image shows you what the Tektronix YouTube Channel looks like.
1. Click on the search icon located just above the video you see when the page first loads.
annel to
NOTE. This icon allows you to search the Tektro
at the top of the page allows you to search all of YouTube .
2. Type in the keyword “WLAN” in the search field.
3. Click the search icon to start the search.
4. Videos related to the topic will appear. Click a video to view it.
nix YouTube channel specifically. The search icon located
6 SPECMONB Series Printable Help
About Tektronix Analyzer Video Tutorials
SPECMONB Series Printable Help 7
About Tektronix Analyzer Video Tutorials
8 SPECMONB Series Printable Help
Orientation Front Panel Connectors
Front Panel Connectors
Fron
Item
1
2TrigIn
3
4
5
xxx
Connector
Trig Out Trigger output connector. 50 Ω, BNC, High > 2.0 V, Low < 0.4 V, (output
USB 2.0 USB 2.0 connector.
USB 2.0 USB 2.0 connector.
RF Input
t-Panel Controls
Descripti
current 1 mA).
External Trigger input connector, –2.5 V to +2.5 V (user settable).
RF input connector 50 Ω.
on
SPECMONB Series Printable Help 9
Orientation Front-Panel Controls
Reference
Item Function Menu Equivalent
1 Media Removable hard disk drive
(optional).
2 Displays
Opens the Disp
lays dialog box
enabling you to select which
displays to open.
3
4 Trigger
Settings Opens/closes the Settings control
panel for th
Opens/clos
e selected display.
es the Trigger control
panel.
5
Acquire
Opens/closes the Acquire control
panel.
6 Analysis
Opens/closes the Analysis control
panel.
7
8
Freq Press to adjust the measurement
cy.
frequen
Span (Sp
ectrum)
Press to adjust the span or press
and hold
to display the Freq & Span
control panel for the General Signal
Viewing displays.
9 Amplitude
10
BW (Sp
ectrum)
Opens/closes the Amplitude control
.
panel
Press to adjust the bandwidth or
and hold to display the BW
press
control panel for the General Signal
Viewing displays.
xxx
Setup > Displa
ys
Setup > Settings
Setup > Trig
ger
Setup > Acquire
Setup > Analysis
Setup > A
nalysis > Frequency
Setup > Amplitude
10 SPECMONB Series Printable Help
Orientation Front-Panel Controls
Reference
11
12
Item Function Menu Equivalent
Run/Stop Starts and sto
Peak (Markers
section)
Moves the active marker to the
maximum peak o
ps acquisitions.
f the trace in the
selected display. If markers are
turned off, the marker reference (MR)
t the maximum peak.
next marker. If markers
13
Select (Mar
section)
kers
will appear a
Selects the
are turned off, the MR marker (marker
reference) will appear.
14
Define (Markers
section)
Opens the Markers control panel.
If markers
are turned off, the MR
marker (reference) will appear.
15
Control knob Changes values in numeric and list
controls. Pressing the knob (clicking
it) is the
same as pressing the Enter
key on a keyboard.
16 Arrow ke
ys
Move the
Markers. TheUparrow
moves the selected marker to the
next highest peak. The down arrow
moves th
e selected marker to the
next lower peak value. The right and
left arrows move the selected marker
ext peak.
to the n
17
18
ment/decre-
Incre
ment keys
Delete, (Markers
Increments or decrements the
ted value
selec
es the selected marker
Delet
section)
19
Add, (Markers
ion)
sect
Add a marker to the selected trace
20 Replay Replays the current acquisition record
21
xxx
Single Sets the Run mode to Single
uence
Seq
Run > Start Run
Markers > Peak
>Stop
SPECMONB Series Printable Help 11
Orientation Front-Panel Controls
Reference
Item Function Menu Equivalent
22 Keypad Enters values in numeric controls.
23 Enter
Completes data entry in controls.
Same as pressi
ng the Enter key on
an external keyboard.
xxx
Reference
24 Recall
25
26
Item Function Menu Equivalent
Opens the Recall dialog box.
Save Opens the Save As dialog box. File > Save As
Touch Screen Off Turns the touch screen on and off. It
is off when lighted.
27 Help Displays the help.
28 Applic
Sets the instrument to the selected
Application Preset values.
29 DPX
Sets the instrument to the selected
DPX Preset values.
30 User
Sets the instrument to the selected
User Preset values.
31 Preset
Returns the instrument to the default
or preset values.
xxx
File > Recall
Help > Online Manual
Presets > Application
Presets > DPX
Presets > User
Preset
12 SPECMONB Series Printable Help
Orientation Touch Screen
Touch Screen
You can use touch to control the instrument in addition to the front-panel controls, mouse, or extended
keyboard. Generally, touch can be used anywhere that click is mentioned in this help.
To disable the touch screen, push the front-panel TouchScreenOffbutton. When the touch screen is off,
the button is lighted. You can still access the on-screen controls with a mouse or keyboard.
You can adjust the touch screen operation to your personal preferences. To adjust the touch screen settings,
from Windows, select Start > Control Panel > Touch Screen Calibrator.
NOTE. If th
need to use a mouse or keyboard to restore normal operation.
Touch-S
You can u
Touch-screen Actions menu.
e instrument is powered on in Windows Safe Mode, the touch screen is inoperative. You will
creen Actions
se the touch screen to change marker settings and how waveforms are displayed by using the
To use the Touch-screen Actions menu, touch the display in a graph area and hold for one second, then
remove your finger. You can also use a mouse to display the Touch-screen Action menu by clicking
the right mouse button.
SPECMONB Series Printable Help 13
Orientation Touch-Screen Actions
Icon Menu Description
Select Selects markers and adjusts their position.
Span Zoom
CF Pan Adjusts the Center Frequency according to horizontal movement.
Zoom
Pan
-
-
-
-
-
-
xxx
ch-Screen Menu for Spurious Display
Tou
Reset Scale
Marker to peak
Next Peak
Add marker
Delete marker Removes the last added marker.
All markers off
Trigger On This Use to visually define trigger parameters in the DPX display
Zooms the graph area about the selected point. Touch the graph
display at a point of interest and drag to increase or decrease the
span about the point of interest. Span Zoom adjusts the span
control and can affect the acquisition bandwidth.
Adjusts horizontal and vertical scale of the graph. The first
direction with enough movement becomes the primary scale of
adjustment. Adjustment in the secondary direction does not occur
until a threshold of 30 pixels of movement is crossed.
Dragging to the left or down zooms out and displays a smaller
waveform (increases the scale value). Dragging to the right or up
zooms in and displays a larger waveform (decreases the scale
value).
Adjusts horizontal and vertical position of the waveform. The first
direction with enough movement becomes the primary direction of
movement. Movement in the secondary direction does not occur
until a threshold of 30 pixels of movement is crossed.
Returns the horizontal and vertical scale and position settings
to their default v alues.
Moves the selected marker to the highest peak. If no marker is
turned on, this control automatically adds a marker.
Moves the selected marker to the next peak. Choices are Next
left, Next right, Next lower (absolute), and Next higher (absolute).
Defines a new marker located at the horizontal center of the graph.
Removes all markers.
(present only in the DPX Spectrum display).
The Touch-screen actions menu in the Spurious display has some minor changes compared to the standard
rsion used in other displays.
ve
14 SPECMONB Series Printable Help
Orientation Elements of the Display
Icon Menu Description
-
-
-
xxx
Single-range Changes the current multi-range display to a single range display.
The displayed range is the range in which you display the
touchscreen-actions menu. Selecting Single-range from the menu
is equivalent to selecting Single on the Settings > Parameters tab.
Multi-range
Marker -> Sel Spur
Changes the current single-range display to a multi-range display.
Selecting Multi-range from the menu is equivalent to selecting
Multi on the Settings > Parameters tab.
Moves the selected marker to the selected spur.
Elements of the Display
The main areas of the application window are shown in the following figure.
SPECMONB Series Printable Help 15
Orientation Elements of the Display
Specific elements of the display are shown in the following figure.
16 SPECMONB Series Printable Help
Orientation Elements of the Display
SPECMONB Series Printable Help 17
Orientation Elements of the Display
Ref
Setting
number
1 Displays
2Markers
3
Settings Opens the Settings control panel for the selected display. Each display has
4 Trigger
5
Acquire
6 Analysis
7
8
Frequenc
Reference Level Displays the reference level. To change the value, click the text and enter a
y
9 Amplitude
10 Repla
y
11 Ru n
12
13 Re
14
ck mark indicator
Che
call
Save Opens the Save As dialog in order to save setup fi les, pictures (screen
15 Presets
16
xxx
Show Shows / hides the selected trace.
Description
Opens the Select Displays dialog box so that you can select measurement
displays.
Opens or closes the Marker toolbar at the bottom of the window.
its own cont
Opens the Tr
Opens the A
Opens the
rol panel.
igger control panel so that you can define the trigger settings.
cquire control panel so that you can define the acquisition settings.
Analysis control panel so that you can define the analysis settings
such as frequency, analysis time, and units.
Displays the frequency at which measurements are made. For spectrum
displays, this is called “Center Frequency”. To change the value, click the
text and
use the front panel knob to dial in a frequency. You can also enter
a frequency with the front panel keypad or use the front panel up and down
buttons.
number
Opens
from the keypad or use the front panel up and down buttons.
the Amplitude control panel so that you can define the Reference Level,
configure internal attenuation, and enable/disable the (optional) Preamplifier.
new measurement cycle on the last acquisition data record using any
Runs a
new settings.
Starts and stops data acquisitions. When the instrument is acquiring data, the
button label has green lettering. When stopped, the label has black lettering.
an specify the run conditions in the Run menu. For example, if you
You c
select Single Sequence in the Run menu, when you click the Run button,
the instrument will run a single measurement cycle and stop. If you select
tinuous, the instrument will run continuously until you stop the acquisitions.
Con
check mark indicator in the upper, left-hand corner of the display indicates
The
the display for which the acquisition hardware is optimized.
When Best for multiple windows is selected in the Amplitude control panel's
& IF Optimization control, none of the measurement displays shows a
RF
checkmark, as there is not a single optimized measurement.
Displays the Open window in order to recall setup files, acquisition data files,
or trace files.
captures), acquisition data files, or export measurement settings or acquisition
data.
Recalls the Main
(see page 23) preset.
18 SPECMONB Series Printable Help
Orientation Rear-Panel Connectors
Rear-Panel Connectors
Item Descripti
1
2
3
4,5
6
7
8 External Trigger 2 lnput
9
10
11
12
13
14
5
1
xxx
AC Input,
GPIB
Zero Spa
Digita
+28 V DC
Microphone in; Headphone, audio output; and Line In connectors
COM 2, serial port for connecting peripherals
VGA external monitor output (resolution not limited to VGA)
PS2 keyboard input
USB 2.0 ports for mouse and other peripherals (printers, external hard disks)
Ref Out, reference frequency output
Ref In, reference frequency input
AN, Ethernet network connector
L
on
main power connector
n Analog Output (Option 66)
l I and Q Outputs (Option 65)
Output, switched
Setting Up Network Connections
Because the instrument is based on Windows, you configure network connections for the instrument the
samewayyouwouldforanyPCbasedonWindows.SeeHelp and Support in the Windows Start menu
to access the Windows Help System for information on setting up network connections.
SPECMONB Series Printable Help 19
Orientation Setting Up Network Connections
20 SPECMONB Series Printable Help
Operating Your Instrument Restoring Default Settings
Restoring D efault Settings
To restore the software to its factory default settings:
1. Select Presets > Preset Options.
2. In the Presets tab of the Options control panel, click to the view the Preset type drop down menu
and select Main.
3. Click to the view the Presets drop down menu and select Original.
4. Click the red X icon in the top right corner of the Options control panel to close the panel.
5. Select Presets > Main from the menu bar to return the software to its original facto
NOTE. You can also press the Preset button on the front-panel or click the Preset button on the right-hand
side of the display menu bar to load the Main preset.
NOTE. The Original Main preset resets all settings and clears all acquisition data (previously recalled
waveform files). Settings that have not been saved will be lost.
Running Alignments
Alignments are adjustment procedures. Alignments are run by the instrument using internal reference
signals and measurements and do not require any external equipment or connections.
There are two settings for Alignments:
Automatically align as needed
Run alignments only when the Align Now button is pressed
If Automatically align as needed is selected, alignments run whenever the signal analyzer detects a
sufficient change in ambient conditions to warrant an alignment
ry default settings.
.
If Run alignments only when "Align Now" button is pressed is selected, the signal analyzer never runs
an alignment unless y ou manually initiate an alignment using the Align Now button.
NOTE. There are a few critical adjustments that must run occasionally even if Automatically align is
not enabled.
Alignment Status
When the signal analyzer needs to run an alignment, it displays a message o n screen. If no mes sage is
displayed, you can assume that the signal analyzer is properly aligned.
SPECMONB Series Printable Help 21
Operating Your Instrument Presets
NOTE. If you must use the instrument before it has completed its 20-minute warm-up period, you should
perform an alignment to ensure accurate measurements.
Initiating an Alignment
1. Select Setup > Alignments.
2. Sel
The signal analyzer will run an alignment procedure. Status messages are displayed while the alignment
procedure is running. If the instrument fails the alignment procedure, an error message will be displayed.
If the instrument fails an alignment, run Diagnostics (Tools > Diagnostics) to see if you can determine
why the alignment failed.
NOTE. While an alignment is running, both the IQ and Zero Span output are disabled.
Alignments during warm-up. During the 2 0-minute warm-up period, the signal analyzer will use the
alignment data generated during the previous use of the instrument as it warms to operating temperature
(if Auto mode is selected). During the specified period for warm-up, the instrument performance is not
warranted.
Alignments during normal operation. Once the signal analyzer reaches operating temperature ±3 degrees C
(as detected inside the instrument), an alignment will be run. If an alignment becomes necessary during a
measurement cycle (if Auto mode is selected), the measurement is aborted and an alignment p rocedure is
run. Once an alignment procedure is completed, the measurement cycle restarts.
NOTE. The first time the instrument runs after a software upgrade (or reinstall), the instrument will
perform a full alignment after the 20–minute warm-up period. This alignment c annot be aborted and it
occurs even if alignments are set to run only when manually initiated.
ect the Align Now button.
Alignments Are Not Calibrations
Alignments are adjustment procedures run by the instrument using internal reference signals and
measurements. Calibrations can only be performed at a Tektronix service center and require the use of
traceable test equipment (signal sources and measuringequipment)toverifytheperformanceofthe
instrument.
Presets
Menu Bar: Presets
The analyzer includes a set of configurations or presets that are tailored to specific applications. These
configurations, referred to as Presets, open selected displays and l oad settings that are optimized to address
specific application requirements.
22 SPECMONB Series Printable Help
Operating Your Instrument Presets
Available Presets
Select Presets from the menu bar to access the available types of Presets:
Main
DPX
Standards
Application
User presets (1 and 2)
How a ctions of these preset selections are defined in the Pesets Options. These are described in the
following table.
SPECMONB Series Printable Help 23
Operating Your Instrument Presets
Presets Description
Main
Current This Preset sets the instrument to disp lay a Spectrum display with settings matched
to show a Spectrum display with settings appropriate for typical spectrum analysis
tasks. This pr
eset was updated from the original factory preset with version 3.2 of the
instrument software.
Original This Preset is the original factory preset used with software versions 1.0 through 3.2.
This version of the factory preset is included to allow users to maintain compatibility with
mote control software.
sets the instrument to display a Spectrum display with the center frequency
Full Spectr
um
existing re
This Preset
set to 1/2 the instrument frequency range and the acquisition bandwidth set to the
maximum real-time bandwidth, which depends on the installed option.
DPX
Open the DPX display The Open the DPX display opens the D PX display without closing existing displays.
Swept The DPX Swept Preset displays the DPX Spectrum display with the span set to maximum
and the center frequency set to 1/2 the span.
Real Time
Zero Sp
an
The DPX Real Time Preset displays the DPX Spectrum display with the center frequency
5 GHz and the span set to the maximum available real-time bandwidth.
set to 1.
The DPX
Zero Span Preset displays the DPX Zero Span display with the position set to
0 s and the sweep set to 1 ms.
Standards
WLAN (see page 225) This preset sets the instrument to display the WLAN Summary, WLAN Constellation, and
SEM displays. After you select the standards and bandwidth, the software configures
e displays to apply the parameters appropriate for typical WLAN analysis tasks.
thes
Application
Time-Frequency Analysis
(see page 27)
ctrum Analysis
Spe
(see
page 27)
Modulation Analysis (see
page 26)
Phase Noise (see page 26)
The Time-Frequency preset configures the instrument with settings suited to analyzing
nal behavior over time.
sig
Spectrum Analysis application preset provide you with the settings commonly used
The
for general purpose spectrum analysis.
e Modulation Analysis setup application preset provides you with the most common
Th
displays used during modulation analysis. Only present when Option 21 is installed.
The Phase Noise application preset opens the Phase Noise display, and makes changes
to the default parameters to settings better optimized for phase noise analysis. Only
resent when Option 11 is installed.
p
User
User Preset 1
This Preset is provided as an example for you to create your own Presets. This preset
displays the Spectrum, Spectrogram, Frequency vs Time, and Time Overview displays.
User Preset 2
This Preset is provided as an example for you to create your own Presets. This preset
displays the Spurious display configured to test for Spurious signals across four ranges.
xxx
Preset Options
Select the Presets > Preset Options menu to open the Options control panel. This panel does the
following. Once you h ave chosen these settings, you can access any preset or list of presets from Presets
on the menu bar.
24 SPECMONB Series Printable Help
Operating Your Instrument Presets
Preset type: Select the Preset type.
Presets: Select which preset you want to display for that particular preset type.
Preset action: Recalling Presets results in either of two actions. One action is to immediately execute
a Preset. The second action displays a list of Presets from which you select the Preset you want to
recall. You can select from Recall selected preset or Show list.
Configuring
After you have selected a preset:
Set the measurement frequency using the front-panel knob or keypad.
Adjust the span to show the necessary detail.
a User Preset
Recalling a Preset
To recall a preset, select Presets and then the desired preset type.
NOTE. You can set which presets to recall from the Presets > Preset Options
To recall a named (User) preset from the front panel, press the button on the front panel matching the preset
type you want to recall. For example, to recall a DPX preset type, press the DPX button.
. You can also click the Preset button on the right-hand side of the menu bar to load the Main preset.
NOTE
NOTE. The only Presets recalled by the front-panel Preset button, the Preset icon in the icon bar, and
*RST remote command are the Main Presets. Application, DPX, Standards, and User Presets can
the
only be recalled using Presets on the menu bar.
(see page 24) control panel.
Creating User Presets
You can add your own presets to the list that appears in the User Presets dialog box. Configure the analyzer
as needed for your application and create a Setup file in C:\SPECMON Files\User Presets. The name you
give the file will be shown in the User Presets list on the Presets tab of the Options control panel. For
instructions on how to save a Setup file, see Saving Data
(see page 437).
Using Standards Presets for WLAN
In addition to accessing Standards presets from the Presets menu bar, you can also click the Standards
Presets button on the WLAN Settings Control Panel to recall these preconfigured WLAN displays for the
standards and bandwidths that you select.
SPECMONB Series Printable Help 25
Operating Your Instrument Presets
NOTE. More information is available about WLAN standards here (see page 225). Youcanalsowatch
a video tutorial about WLAN Presets at www.youtube.com/user/tektronix. Click here
information a
bout searching the Tektronix YouTube channel for videos.
(see page 6) for
Modulation Analysis
The Modulation Analysis application preset opens the following displays:
Signal Qual
Error, Phase Error, and others).
Constella
Symbol Table: Shows the demodulated symbols of the signal.
To use the Modulation Analysis preset (assuming the Preset action is set to Show list in the Presets tab
of the Options control panel):
1. Select Presets > Application.SelectModulation Analysis andthenclickOK.
2. Set the measurement frequency using the front-panel knob or keypad. Your signal should appear in
the DPX display.
3. Set the reference level so that the pea k of y our signal is about 10 dB below the top of the DPX display.
4. Set the modulation parameters for your signal. This includes the Modulation Type, Symbol Rate,
Measurement F ilter, Reference Filter and Filter Parameter. All of these settings are accessed by
pressing the Settings button.
For most modulated signals, the Modulation Analysis application preset should present a stable display of
modulation quality. Additional displays can be added by using the Displays button, and other settings can
be modified to better align with your signal requirements.
ity: Shows a summary of modulation quality measurements (EVM, rho, Magnitude
tion: Shows the I and Q information of the signal analyzed in an I vs. Q format.
Phase Noise
e Phase Noise application preset opens the Phase Noise display.
Th
Pulse Analysis
The Pulse Analysis application preset opens the following displays:
Time Overview: Shows amplitude vs. time over the analysis period.
Pulse Trace: Shows the trace of the selected pulse and a readout of the selected measurement from
the pulse table.
Pulse Measurement Table: This shows a full report for the user-selected pulse measurements.
You can make a selected pulse and measurement appear in the Pulse Trace display by highlighting it in the
Pulse Measurement Table. Key pulse-related parameters that are set by the Pulse Analysis application
preset are:
26 SPECMONB Series Printable Help
Operating Your Instrument Presets
Measurement Filter: No Filter.
Measurement Bandwidth: This is set to the maximum real-time bandwidth of the instrument (25 MHz
in a base instrument, 40 MHz in instruments with Option B40, 85 MHz in instruments with Option B85,
or 165 MHz in instruments with Option B16x). Note: The label on the “Measurement Bandwidth”
setting is ju
presets, the Pulse Analysis application preset also sets most other instrument controls to default values.
st “Bandwidth”. Like the main instrument Preset command and the other application
Analysis Pe
typical signals.
To use the P
Options control panel):
1. Select Pr
2. Set the Center Frequency control to the carrier frequency of your pulsed signal.
3. Set the Reference Level to place the peak of the pulse signal approximately 0-10 dB down from
the top of the Time Overview display.
You may need to trigger on the signal to get a more stable display. This is set up in the Trigger control
panel. (“Trig” button). Using the Power trigger type with the RF Input source works well for many
pulse
4. Set the Analysis Period to cover the number of pulses in your signal that you want to analyze. To do
click in the data entry field of the Time Overview window and set the analysis length as needed.
this,
riod: This is set to 2 ms to ensure a good probability of catching several pulses for
ulse Analysis preset (assuming the Preset action is se t to Show list in the Presets tab of the
esets > Application. Select Pulse Analysis and then click OK.
d signals.
Spectrum Analysis
The Spectrum Analysis application preset opens a Spectrum display and sets several parameters. The
Spectrum Analysis preset sets the analyzer a s follows.
Spectrum Analysis : Sets the frequency range to maximum for the analyzer, and sets the RF/IF
optimization to Minimize Sweep Time.
To use the Spectrum Analysis preset (assuming the Preset action is set to Show list in the Presets tab
of the Options control panel):
1. Select Presets > Application.SelectSpectrum Analysis andthenclickOK.
2. Set the measurement frequency using the front-panel knob or keypad.
3. Adjust the span to show the necessary detail.
Time-Frequency Analysis
The Time-Frequency Analysis application preset opens the following displays:
Time Overview: Shows a time-domain view of the analysis time ‘window’.
Spectrogram: Shows a three-dimensional view of the signal where the X-axis represents frequency,
the Y-axis represents time, and color represents amplitude.
SPECMONB Series Printable Help 27
Operating Your Instrument Setting Options
Frequency vs. Time: This display's graph plots changes in frequency over time and allows you to
make marker measurements of settling times, frequency hops, and other frequency transients.
Spectrum: Shows a spectrum view of the signal. The only trace showing in the Spectrum graph
after selecting the Time-Frequency Analysis preset is the Spectrogram trace. This is the trace from
the Spectrogram display that is selected by the active marker. Stop acquisitions with the Run button
because its easier to work with stable results. In the Spectrogram display, move a marker up or down
to see the spectrum trace at various points in time.
Theanalysisperiodissetto5ms.
To use the Time-Frequency Analysis preset (assuming that Time-Frequency Analysis is the selected preset
on the list of Application Presets and Preset action is set to Recall selected preset):
1. Select Presets > Application.SelectTime-Frequency Analysis and then click OK.
2. When the preset's displays and settings have all been recalled and acquisitions are running, adjust the
center frequency and span to capture the signal of interest.
3. Set the Reference Level to place the peak of the signal approximately 0-10 dB down from the top of
the Spectrum graph.
4. If the signal is transient in nature, you might need to set a trigger to capture it. For more information
on triggering in the time and frequency domain, see Triggering
(see page 416).
When the signal has been captured, the spectrogram shows an overview of frequency and amplitude
changes over time. To see frequency transients in greater detail, use the Frequency vs. Time display.
The Time-Frequency Analysis preset sets the analysis period to 5 ms. The Spectrum Span is 40 MHz. The
RBW automatically selected for this Span is 300 kHz. For a 300 kHz RBW, the amount of data needed for
a single spectrum transform is 7.46 μs. A 5 ms Analysis Length yields 671 individual spectrum transforms,
each one forming one trace for the Spectrogram to display as horizontal colored lines. This preset scales
the Spectrogram time axis (ver
time compression, resulting in one visible line for each four transforms. This results in 167 lines in the
Spectrogram for each acquisition, each covering 29.84 μs.
Setting Options
Menu Bar: Tools > Options
There are several settings you can change that are not related to measurement functions. The Option
settings control panel
tical axis) to -2, which means that the Spectrogram has done two levels of
is used to change these settings.
28 SPECMONB Series Printable Help
Operating Your Instrument Setting Options
Settings tab
Presets
Analysis Time
Save and Export Use this tab to specify whether or not save files are named automatically and what
GPIB Use this tab
Security Selecting
Prefs Use this tab to select different color schemes for the measurement graphs and specify
xxx
Description
Use this tab to
recalled and which preset to recall when the Preset button is selected.
Use this tab to specify the method used to automatically set the analysis and spectrum
offsets when the Time Zero Reference
informatio
measurement readouts with a string of asterisks.
how markers to automatically jump to the next peak
When this
configure Presets. You can specify the action to take when a preset is
(see page 387) is set to Trigger.
n is saved in acquisition data files.
to set the primary GPIB address for the instrument.
the Hide Sensitive readouts check box causes the instrument to replace
(see page 376) when you drag them.
setting is deselected, you can drag a marker to any point on the trace.
Presets
The Presets tab in the Options control panel allows you to specify actions taken when you press the Preset
button. You can read more about this tab here
(see page 24).
Analysis Time
The An
the analysis and spectrum offsets when the Time Zero Reference
available settings are:
alysis Time tab i n the Options control panel is used to specify the method used to automatically set
(see page 387) is set to Trigger. The
Include trigger point – Selects an algorithm that uses the measurements to determine how far in
advance of the trigger to set the analysis offset. The analyzer tries to ensure that data about the trigger
point is included in the analyses.
Start at trigger point (legacy) – The method used by the instrument in prior versions, which sets the
Analysis Offset to zero when possible. The analyzer tries to ensure that data following the trigger
point is included in the analyses. Use this method if your measurements or procedures depend on past
behavior of the Auto Analysis Offset function.
Save and Export
The Save and Export tab allows you to specify whether or not files are saved with an automatically
generated name, and how much data is saved in an acquisition data file.
All files. The Automatically increment filename/number function can automatically name saved files by
appending a number to a base file name. Use this tab to enable/disable automatic naming of files. For
example, if Automatically Increment Filename Number is disabled, when you select Save from the File
menu, you will have to enter a name for the file.
Acquisition data files. This setting specifies whether saved data files include the entire acquisition record or
only the data for the analysis length (a subset of the acquisition record). You can choose from the following:
SPECMONB Series Printable Help 29
Operating Your Instrument Setting Options
IQ records: Includes IQ records
DPX spectra: Includes DPX spectra
Both: Includes both IQ records and DPX spectra
You can also select to include an entire IQ record or just the analysis length of it.
TIQ acquisition data files. Specifies which data records to save. You can choose from the following:
Current acquisition: Saves the current acquisition.
Current frame: If Fast Frame is enabled, saves only the current frame. The current frame is the
one most recently analyzed.
Selected frames: If Fast Frame is enabled, saves the specified frames.
All in his
Save TIQ file now: Invokes the Save As dialog box with the Save as type drop-down list set to TIQ.
tory: Saves all acquisition records in the history.
Security
The Sec
Summary display.
urity tab enables you to hide sensitive readouts in displays with readouts, such as the OFDM
Prefs
The Prefs tab enables you to set properties that apply to all displays.
Color scheme. The Color scheme setting provides three color schemes for the measurement graphs. The
color scheme setting does not change the overall instrument application or Windows color scheme.
Thunderstorm – This scheme displays graphs in shades of blue. This provides a less vibrant color
scheme than the default setting.
Blizzard – This scheme displays graphs with a w hite background to save ink when printing.
Classic – The default setting. This scheme displays the graph area with a black background.
Markers snap to peaks when dragged. When selected, this setting causes makers to automatically jump
to the next peak
marker to any point on the trace.
(see page 376) when you drag them. When this setting is deselected, you can drag a
30 SPECMONB Series Printable Help
Operating Your Instrument Operating System Restore
Operating System Restore
The instrument contains an operating system restore file on a separate partition of the hard drive.
CAUTION. Using the restore process reformats the hard drive and reinstalls the operating system. All
saveddatais
1. Restart the instrument. During the boot-up process you will see the following message at the top of the
screen: Sta
NOTE. To successfully complete the system restore, you must use the Windows version of the Acronis
software. Using a generic Macinto sh keyboard starts the DOS version of the Acronis software. Do not use
a Macintosh keyboard.
2. Repeatedly press the F5 key until the Acronis True Image Tool opens. There is a 5-second time period
from when the message appears until the instrument proceeds with the normal instrument startup. If
the instrument does not open the Acronis application, power off the instrument, then power on the
instrument and try again.
lost. If possible, save important files to external media before performing a system restore.
rting Acronis Loader... press F5 for Acronis Startup Recovery Manager.
3. Click Restore.
4. In the Confirmation dialog box, click Yes to restore the instrument operating system, or No to exit
the restore process. The restore process takes approximately 30 minutes; the actual time depends on
the instrument configuration.
SPECMONB Series Printable Help 31
Operating Your Instrument Operating System Restore
32 SPECMONB Series Printable Help
Using the Measurement Displays Selecting Displays
Selecting Displays
Menu Bar: Setup > Displays
Application Toolbar:
Use the Select Displays dialog to choose the displays that appear on the screen.
To select displays:
1. Press the Displays button or select Setup > Displays.
2. Select one of the choices under Folders. The folder chosen determines the choices available in
Available displays .
3. Double-click the desired display in the Available displays box or select the desired display and
click Add.
4. Click OK.
Interactions Between Displays
Different displays can require different settings, for example acquisition bandwidth, analysis length, or
resolution bandwidth, to achieve optimum results. The application automatically adjusts some settings
to optimize them for the selected display. The check mark indicator in the upper, left-hand corner of the
SPECMONB Series Printable Help 33
Using the Measurement Displays Selecting Displays
display indicates the display for which the application is optimized. Depending on application settings,
some displays might stop displaying results if they are not the selected display.
34 SPECMONB Series Printable Help
Taking Measurements Available Measurements
Available Measurements
The automatic measurements available include RF power measurements, OFDM analysis, WLAN
analysis, Audio analysis, analog modulation measurements, digital modulation measurements, and pulsed
RF measurements.
Power Measu
Measurement Description
Channel Power The total RF power in the selected channel (located in the Chan Pwr and ACPR display).
Adjacent Channel Power Ratio
(ACPR)
Multi-Carrier Power Ratio
(MCPR)
Peak/Avg Ratio Ratio of the peak power in the transmitted signal to the average power in the transmitted
CCDF The Complementary Cumulative Distribution Function (CCDF). CCDF shows how much
xxx
rements
Measure of the signal power leaking from the main channel into adjacent channels.
The ratio of the signal power in the reference channel or group of channels to the power
in adjacent channels.
signal (located in the CCDF display).
time a signal spends at or above a given power level relative to the average power of
a measured signal.
OFDM Analysis
Measurement Description
Channel Response Plots the channel response (magnitude or phase) versus the subcarrier or frequency.
Here, the channel refers to all sources of signal frequency response impairment up to
the analyzer input, including the transmitter itself, as well as any transmission medium
through which the signal travels between the transmitter and the analyzer.
Constellation Measure of the signal power leaking from the main channel into adjacent channels.
EVM
Flatness
Mag Error
Phase Error
Power
xxx
The normalized RMS value of the error vector between the measured signal and the ideal
reference signal over the analysis length. The EVM is generally measured on symbol or
chip instants and is reported in units of percent and dB. EVM is usually measured after
best-fit estimates of the frequency error and a fixed phase offset have been removed.
These estimates are made over the analysis length. Displays RMS and Peak values with
location of Peak value.
Ratio of the peak power in the transmitted signal to the average power in the transmitted
signal
The RMS magnitude difference between the measured signal and the reference signal
magnitude. Displays RMS and Peak values with location of Peak value.
The RMS phase difference between the measured signal and the ideal reference signal.
Displays RMS and Peak values with location of Peak value.
shows the data symbols' individual subcarrier Power values versus symbol interval (time)
and subcarrier (frequency).
SPECMONB Series Printable Help 35
Taking Measurements Available Measurements
WLAN Measurements
Measurement Description
Channel Response Plots the channel response (magnitude or phase) versus the subcarrier or frequency.
Here, the channel refers to all sources of signal frequency response impairment up to
the analyzer i
nput, including the transmitter itself, as well as any transmission medium
through which the signal travels between the transmitter and the analyzer.
Constellation Measure of the signal power leaking from the main channel into adjacent channels.
EVM
The normalized RMS value of the error vector between the measured signal and the ideal
reference signal over the analysis length. The EVM is generally measured on symbol or
chip instan
ts and is reported in units of percent and dB. EVM is usually measured after
best-fit estimates of the frequency error and a fixed phase offset have been removed.
These estimates are made over the analysis length. Displays RMS and Peak values with
f Peak value.
he peak power in the transmitted signal to the average power in the transmitted
Flatness
location o
Ratio of t
signal
Mag Error
The RMS magnitude difference between the measured signal and the reference signal
magnitude. Displays RMS and Peak values with location of Peak value.
Phase Error
Power vs Time
The RMS phase difference between the measured signal and the ideal reference signal.
ys RMS and Peak values with location of Peak value.
Displa
nal power amplitude versus time. For 802.11b signals, the packet Power-On and
The sig
Power-Down ramp times are also m easured.
Summary Shows several measurements of WLAN signal quality.
Symbol Table Shows decoded data values for each data symbol in the analyzed signal packet. For
OFDM (non-802.11b) signals, results are presented with subcarrier (frequency) indices
e horizontal dimension and symbol (time) intervals in the vertical dimension. For
in th
802.11b signals, the Preamble, Header, and Data (PSDU) symbol values are presented
sequentially, with symbol indices in the left column.
xxx
Audio Measurements
Measurement Description
Audio Spectrum Shows audio modulation characteristics. You can choose to show just the spectrum of
the audio signal or show the audio spectrum of the signal and the results of distortion
measurements. The Audio Spectrum display can show a table listing the frequency
of a Harmonic Distortion (HD) and Non-Harmonic Distortion (NHD) and its level. The
Spectrum graph indicates these harmonics and non-harmonics with special markers.
xx
x
36 SPECMONB Series Printable Help
Taking Measurements Available Measurements
Digital Modulation Measurements
Measurements for all modulation types except nFSK, C4FM, OQPSK and SOQPSK
Measurement Description
EVM
Phase Error
Mag Error
MER (RMS) The MER is defined as the ratio of I/Q signal power to I/Q noise power; the result is
IQ Origin Offset The magnitude of the DC offset of the signal measured at the symbol times. It indicates
Frequency Error
Gain Imbalance The gain difference between the I and Q channels in the signal generation path.
Quadrature Error The orthogonal error between the I and Q channels. The error shows the phase
Rho
xxx
The normalized RMS value of the error vector between the measured signal and the ideal
reference signal over the analysis length. The EVM is generally measured on symbol or
chip instants and is reported in units of percent and dB. EVM is usually measured after
best-fit estimates of the frequency error and a fixed phase offset have been removed.
These estimates are made over the analysis length. Displays RMS and Peak values with
location of Peak value.
The RMS phase difference between the measured signal and the ideal reference signal.
Displays RMS and Peak values with location of Peak value.
The RMS magnitude difference between the measured signal and the reference signal
magnitude. Displays RMS and Peak values with location of Peak value.
indicatedindB.
the magnitude of the carrier feed-through signal.
The frequency difference between the measured carrier frequency of the signal and the
user-selected center frequency of the instrument.
Constellations with gain imbalance show a pattern with a width that is different form
height.
difference between I and Q channels away from the ideal 90 degrees expected from the
perfect I/Q modulation. Not valid for B PSK modulation type.
The normalized correlated power of the measured signal and the ideal reference signal.
Like EVM, Rho is a measure of modulation quality. The value of Rho is less than 1 in all
practical cases and is equal to 1 for a perfect signal measured in a perfect receiver.
SPECMONB Series Printable Help 37
Taking Measurements Available Measurements
Measurements for OQPSK and SOQPSK modulation types
Measurement Description
EVM
Offset EVM Offset EVM is like EVM except for a difference in the time alignment of the I and Q
Phase Error
Mag Error
MER (RMS) The MER is defined as the ratio of I/Q signal power to I/Q noise power; the result is
in Offset
IQ Orig
ncy Error
Freque
Gain Imbalance The gain difference between the I and Q channels in the signal generation path.
Quadrature Error The orthogonal error between the I and Q channels. The error shows the phase
Rho
xxx
The normalized RMS value of the error vector between the measured signal and the ideal
reference sig
nal over the analysis length. The EVM is generally measured on symbol or
chip instants and is reported in units of percent and dB. EVM is usually measured after
best-fit estimates of the frequency error and a fixed phase offset have been removed.
These estima
tes are made over the analysis length. Displays RMS and Peak values with
location of Peak value.
samples. For EVM, I and Q samples are collected at the same time, for every symbol
decision po
int (twice the symbol rate for offset modulations). For Offset EVM, the I and Q
symbol decision points are time-aligned before collecting the I and Q samples. In this
case, one I and one Q sample is collected for each symbol (half as many samples as the
same numbe
The RMS pha
r of symbols for (non-offset) EVM.
se difference between the measured signal and the ideal reference signal.
Displays RMS and Peak values with location of Peak value.
The RMS magnitude difference between the measured signal and the reference signal
magnitude. Displays RMS and Peak values with location of Peak value.
ed in dB.
indicat
The mag
nitude of the DC offset of the signal measured at the symbol times. It indicates
the magnitude of the carrier feed-through signal.
The frequency difference between the measured carrier frequency of the signal and the
user-selected center frequency of the instrument.
ellations with gain imbalance show a pattern with a width that is different form
Const
height.
difference between I and Q channels away from the ideal 90 degrees expected from the
fect I/Q modulation. Not valid for BPSK modulation type.
per
normalized correlated power of the measured signal and the ideal reference signal.
The
Like EVM, Rho is a measure of m odulation quality. The value of Rho is less than 1 in all
practical cases and is equal to 1 for a perfect signal measured in a perfect receiver.
38 SPECMONB Series Printable Help
Taking Measurements Available Measurements
Measurements for nFSK modulation types
Measurement Description
Peak FSK err Peak value of the frequency deviation error at the symbol point.
RMS FSK Err RMS value of the frequency deviation error at the symbol point.
Peak Mag Err
The Peak magnitude difference between the measured signal and the reference signal
magnitude.
RMS Mag Err The RMS magn
itude difference between the measured signal and the reference signal
magnitude.
Freq Error
The frequency difference between the measured carrier frequency of the signal and the
user-selected center frequency of the instrument.
Freq Deviation
Frequency distance from the center frequency at the symbol point.
Symbol Rate Error This compares the user-entered symbol rate to the instrument calculated symbol rate of
yzed signal.
the anal
Symbol R
ate
When in A
uto-symbol rate, the instrument calculates the symbol rate of the signal and
the instrument calculates the error between the user entered value and the instrument
calculated value.
xxx
Measurements for C4FM modulation type
Measurement Description
RMS Error Magnitude RMS value of the frequency deviation error at the symbol point.
Carrier Frequency Error Frequency difference between averaged signal frequency and the center frequency.
Deviation
Length
xxx
Frequency distance from the center frequency at the symbol point.
Number of symbols in the analysis area.
Analog Modulation Measurements
asurements for AM modulation
Me
asurement
Me
+AM Positive peak AM value.
-AM Negative peak AM value.
otal AM
T
xxx
Measurements for FM modulation
Measurement Description
+Pk
–Pk
RMS RMS value of the frequency deviation.
Pk-Pk/2 Peak-to-peak frequency deviation divided by 2.
Pk-Pk
xxx
scription
De
otal AM value, which is equal to the peak-peak AM value divided by 2.
T
Positive peak frequency deviation.
Negative peak frequency deviation.
Peak-to-peak frequency deviation.
SPECMONB Series Printable Help 39
Taking Measurements Available Measurements
Measurements for PM modulation
Measurement Description
+Pk Positive peak phase deviation.
–Pk Negative peak
RMS RMS value of t
phase deviation.
he phase deviation.
Pk-Pk Peak-to-peak phase deviation.
xxx
Pulse Measurements
Measurement Description
Average ON Power
Peak Power Maximum power during pulse on.
Average Transmitted Power The average power transmitted, including both the time the pulse is on and the time
Pulse Width
Rise Time
Fall Time
Repetition Interval
Repetition Rate
Duty Factor (%) The ratio of the width to the pulse period, expressed as a percentage.
Duty Factor (Ratio) The ratio of the pulse width to the pulse period.
Ripple Ripple is the peak-to-peak ripple on the pulse top. It does not include any preshoot,
Ripple dB The Ripple measurement expressed in dB.
Droop
Droop dB The Droop measurement expressed in dB.
Overshoot The amount by which the signal exceeds the 100% level on the pulse rising edge. Units
Overshoot dB The Overshoot measurement expressed in dB.
Pulse-Pulse Phase Difference The phase difference between the selected pulse and the first pulse in the a nalysis
The average power transmitted during pulse on.
it is off, and all transition times.
The time from the rising edge to the falling edge at the –3 dB / –6 dB level (50%) of the
user selected 100% level. Level is user selectable for Volts or Watts.
The time required for a signal to rise from 10% to 90% (or 20% to 80%) of the user
selected 100% lev el.
The time required for a signal to fall from 90% to 10% (or 80% to 20%) of the user
selected 100% lev el.
The time from a pulse rising edge to the next pulse rising edge.
The inverse of repetition interval.
overshoot, or undershoot. By default, the first 25% and the last 25% of the pulse top is
excluded from this measurement to eliminate distortions caused by these portions of
the pulse.
If the Amplitude units selected in the Amplitude panel (affects all amplitude measurements
for the analyzer) are linear, the Ripple results will be in %Volts. For log units, the Ripple
results will be in %Watts. The default for the general Units control is dBm, so the Ripple
resultsdefaultis%Watts.
See also Ripple
(see page 491).
Droop is the power difference between the beginning and the end of the pulse On time. A
straight-line best fit is used to represent the top of the pulse. The result is a percentage
referenced to the Average ON Power.
are %Watts or %Volts.
window. The instantaneous phase is measured at a user-adjustable time following the
rising edge of each pulse.
40 SPECMONB Series Printable Help
Taking Measurements Available Measurements
Measurement Description
Pulse-Pulse Freq Difference The difference between the frequency of the current pulse and frequency of the previous
pulse. The ins
rising edge of each pulse.
RMS Freq Error The RMS Frequency Error measurement is the RMS average of the Freq Error vs. Time
trace, computed over the Measurement Time.
Max Freq Error
The maximum frequency error is the difference between the measured carrier frequency
of the signa
RMS Phase Er
ror
The RMS Phas
computed over the Measurement Time.
Max Phase E
rror
The phase is measured at each point during the pulse's ON time. The phase error for
each point is the difference between the m easured phase value and the calculated ideal
phase val
the largest error in the positive direction and the largest in the negative direction are
determined. Whichever of these two values has the greater absolute value is designated
the Max Ph
Freq Deviation
The Freq
minimum measured values of the signal frequency during the Measurement Time.
Delta Frequency (Non-chirped
pulse)
The Delta Frequency measurement is the difference from the measurement frequency
to each pulse frequency. Pulse frequency is calculated across the time defined by the
Freque
The measurement is available for modulation types CW (Constant Phase), CW
(Changing phase). and Other (manual) setting in the Freq Estimation tab.
The me
when frequency estimation is set to Chirp.
If frequency estimation is set to Other, then Frequency Offset must be set to 0 Hz and the
Range
A least-square fit of slope of phase vs. time over the measurement period is used for the
measurement of the individual pulse frequency. Frequency difference is calculated as the
erence between the reference frequency and the calculated frequency of the pulse.
diff
Phase Deviation
Phase Deviation is the difference between the maximum and minimum Phase values
The
measured during the ON time of a pulse.
ulse Response Amplitude
Imp
pulse Response Time
Im
me
Ti
The difference in dB between the levels of the main lobe and highest side lobe.
The difference in time between the main lobe and highest side lobe.
This is the time in seconds relative to the time reference point in the first acquisition
record in the data set.
xxx
tantaneous frequency is measured at a user-adjustable time following the
l and the user-selected center frequency of the analyzer.
e Error measurement is the RMS average of the Phase vs Time trace,
ue. After the phase error is calculated for a ll points in the acquisition record,
ase Error.
uency Deviation measurement is the difference between the maximum and
ncy Domain Linearity setting in the Define tab.
asurement is not specified for chirp or other signals and no answer is returned
can be set to ±40% of the acquisition bandwidth.
SPECMONB Series Printable Help 41
Taking Measurements Available Measurements
42 SPECMONB Series Printable Help
General Signal Viewing Overview
Overview
The displays in the General Signal Viewing folder (Displays > Folders > General Signal Viewing) are:
Amplitude vs Time
DPX Spectrum
Frequency vs Time
Phase vs Tim
RF I & Q vs Time
Spectrogram
Spectrum
Time Overview
These displays provide extensive time-correlated multi-domain views that connect problems in time,
frequency, phase and amplitude for enabling you to more quickly understand cause and effect when
troubleshooting.
DPX Primer
With the DPX display (which displays only DPX waveforms saved by RSA5000/RSA6000/SPECMON
Series Real-Time Signal Analyzers), you can detect and accurately measure transients as brief as 2.7 µs.
The instrument computes up to 390,625 spectrums per second of the digitized input signal. Then it
displays all these spectrums as a color-graded bitmap that reveals low-amplitude signals beneath stronger
signals sharing the same frequency at different times.
The strong signal in the DPX spectrum graph, showninFigure1,isarepeatingpulseatafixed frequency.
There is also a lower-power CW signal that steps very quickly through the same span. During the pulse's
time, the power of the two signals is additive, resulting in nearly undetectable differences in the pulse
on
envelope shape. But during the time the pulse is off, the sweeping signal is detected and shown in its true
form. Both signals are visible in the bitmap because at least one full cycle of their activities occurs
within a single DPX display update.
e
SPECMONB Series Printable Help 43
General Signal Viewing DPX Primer
Figure 1
Compare the display of a traditional swept spectrum analyzer (Figure 2) and that of a real-time signal
analyzer with a DPX display (Figure 3). The signal c aptured is a typical WLAN interchange between
a nearby PC and a more-distant network access point (AP). The laptop signal is nearly 30 dB stronger
than the AP's signal because it is closer to the measuring antenna.
Figure 2
Figure 3
The traditional swept spectrum analyzer display, Figure 2, uses line traces that can show only one level for
each frequency point, representing the largest, the smallest or the average power. After many sweeps, the
44 SPECMONB Series Printable Help
General Signal Viewing DPX Primer
Max Hold trace shows a rough envelope of the stronger laptop signal. +Peak detection was selected for the
other trace in an attempt to capture the weaker but more frequent AP signal, but the bursts are very brief,
so the likelih
capture the entire spectrum of a bursted signal due to the architecture of the swept spectrum analysis.
ood of seeing one in any particular sweep is small. It will also take a long time to statistically
The DPX displ
instead of a line trace, you can distinguish many different signals occurring within each update period
and/or different version of the same signal varying over time. The heavy band running straight across the
lower third of the graph is the noise background when neither the laptop nor the AP is transmitting. The red
lump of energy in the middle is the ON shape of the AP signal. Finally, the more delicate spectrum above
the others is the laptop transmissions. In the color scheme used for this demonstration (“Temperature”),
the hot red
laptop signal, in yellow, green and blue, has higher amplitude but doesn't occur nearly as often as the AP
transmissions because the laptop was downloading a file when this screen capture was taken.
ay, Figure 3, reveals much more insight on the same signal. Since it is a bitmap image
color indicates a signal that is much more frequent than signals shown in cooler colors. The
How DPX Works
This section explains how DPX displays are created. The input RF signal is conditioned and
down-converted as usual for a signal analyzer, then digitized. The digitized data is sent through an FPGA
that computes very fast spectral transforms, and the resulting frequency-domain waveforms are rasterized
ate the bitmaps.
to cre
The DPX bitmap that you see on screen is composed of pixels representing x, y, and z values for frequency,
itude, and Density. A multi-stage process, shown in Figures 4a - 4d, creates this bitmap, starting with
ampl
analog-to-digital conversion of the input signal.
Simplified Flow of Multi-stage Processing from RF Input Through to Spectrum Processing:
Figure 4a. RF signals are downconverted and sampled into a continuous data stream.
Figure 4b. Samples are segmented into data records for FFT processing based on the selected resolution bandwidth.
Figure 4c. Data records are processed in the DPX transform engine
SPECMONB Series Printable Help 45
General Signal Viewing DPX Primer
Figure 4d. Overlapping the FFTs shortens the minimum event duration required for 100% probability of inte
rcept.
Collecting spectral data. Sampling and digitization is continuous. The digitized data stream is chopped
into data records whose length is based on the desired resolution bandwidth (RBW). An additional
requirement is placed on FFT length by the desired number of points in a trace. Table 1 shows this
relationship and the FFT length is reported in the display if desired. Then the DPX transform engine
performs a discrete Fourier transform on each record, continually producing spectral waveforms.
Table 1: Minimum FFT length versus trace length – independent of span and RBW
Trace length (points) Minimum FFT length
801 1,024
2,401 4,096
4,001 8,192
10,401 16,384
xxx
As long as spectral transforms are performed faster than the acquisition data records arrive, the transforms
can overlap each other in time, so no events are missed in between. Minimum event length for guaranteed
capture depends on the length of the data records being transformed. An event must last through two
consecutive data records in order for its amplitude to be accurately measured. Shorter events are detected
and visible on screen, but may be attenuated. The DPX Spectrum RBW setting determines the data
record length; narrow RBW filters have a longer time constant than wide RBW filters. This longer time
constant requires longer FFTs, reducing the transform rate. Additional detail on minimum signal duration
is provided in Guaranteed Capture of Fast Events
(see page 52).
The spectral waveforms are plotted onto a grid of counting cells called the “bitmap database”. The number
held by each database cell is the z-axis count. For simplicity, the small example grid used here in Figure 6
is 11x10, so our spectral waveforms will each contain 11 points. A waveform contains one (y) amplitude
value for each (x) frequency. As waveforms are plotted to the grid, the cells increment their values each
time they receive a waveform point.
Figure 5. Example 3-D Bitmap Database after 1 (left) and 9 (right) updates. Note that each column contains
the same total number of “hits”.
46 SPECMONB Series Printable Help
General Signal Viewing DPX Primer
The grid on the left shows what the database cells might contain after a single spectrum is plotted into it.
Blank cells contain the value zero, meaning that no p oints from a spectrum have fallen into them yet.
The grid on the right shows values that our simplified database might contain after an additional eight
spectral transforms have been performed and their results stored in the cells. One of the nine spectrums
happened to be computed as a time during which the signal was absent, as you can see by the string of “1”
occurrence counts at the noise floor.
Frame updates. The maximum rate for performing the variable-length frequency transforms that produce
those waveforms can b e greater than 390,625 per second. Measur
ement settings that slow this transform
rate include narrowing the RBW and increasing the number of points for the line traces available in the
DPX display along with the bitmap. Even at their slowest, spectral transforms are performed orders of
magnitude faster than a physical display can respond, and also too fast for humans to see, so there's no
need to update the screen or measurements at this rate. Instead, the grid collects thousands of waveforms
into “frames”, each covering about 50 milliseconds (ms). A 50 ms frame contains the counts from up to
14,600 waveforms. After each frame's waveforms have been
mapped into the grid, the cell occurrence
counts are converted to colors and written to the DPX bitmap, resulting in a bitmap update rate of
around 20 per second.
Frame length sets the time resolution for DPX measurements. If the bitmap shows that a -10 dBm
signal at 72.3 MHz was present for 10% of one frame's duration (5 ms out of 50 ms), it isn't possible to
determine just from the DPX display whether the actual signal contained a single 5 ms pulse, one hundred
50 microsecond (μs) pulses, or something in between. For this information, you need to examine the
spectral details of the signal or use another display with finer time resolution, such as Frequency vs.
Time or Amplitude vs. Time.
Converting occurrence counts to color. About 20 times per second, the grid values are transferred to the
next process step, in which the z-axis values are mapped to pixel colors in the visible bitmap, turning
data into information (Figure 6). In this example, warmer colors (red, orange, yellow) indicate m
ore
occurrences. The color palette is user-selectable, but for now we will assume the default “temperature”
palette.
Number of Occurrences Color
0black
1blue
2 light blue
3
4 green blue
5
6yellow
7
8 red orange
9red
Figure 6. Example Color-mapping algorithm
xxx
cyan
green
orange
The result of coloring the database cells, Figure 7, according to the number of times they were written into
by the nine spectrums, one per pixel on the screen, creates the DPX displays.
SPECMONB Series Printable Help 47
General Signal Viewing DPX Primer
Figure 7. Color-coded low-resolution example (left) and a real DPX display (right).
In addition to the choice of palette, there are z-axis scaling adjustments for Maximum, Minimum, and
Curve. Maximum sets the occurrence value that will be mapped to the highest color in the palette.
Minimum sets the occurrence value for the lowest color. In the “ temperature” palette, the highest color is
deep red and the lowest is dark blue. Occurrence values less than the selected Minimum are represented
with black pixels, while pixels that exceed the selected Maximum are red in hue but somewhat transparent.
Values b
Adjusting the Minimum above the black default allows you to concentrate most of your color resolution
over a s
that have nearly equal probability values.
etween Maximum and Minimum are represented by the other colors of the palette.
mall range of medium or higher occurrence rates to visually discriminate between different signals
To see
set to 100% in Figure 8. The range of colors now covers the full z-axis range of densities from 0 to 100%.
The signals used to create this bitmap are fairly diffused in both frequency and amplitude, so most pixels
have low occurrence counts or density values and the upper half of the color palette is unused.
Figure 8. DPX spectrum bitmap with default color scale settings.
When the Auto Color button is selected, the Maximum control's value is set to the highest pixel value
in the current bitmap, shown in Figure 9. Now none of the available colors remain unused. The e ntire
palette is mapped to the occurrence values present at the time the button is selected, providing better
why adjustable color scaling is useful compare Figures 8 and 9. On the Scale tab, the Max control is
48 SPECMONB Series Printable Help
General Signal Viewing DPX Primer
visual resolution for low densities. Selecting the Autoscale button in the DPX display scales all three
axes based on current results.
Figure 9. The Auto Color function optimizes the color scale settings.
Color Mapping Curves
The mappi
choose the shape of the mapping equation. A Curve setting of 1 selects the straight-line relationship.
Higher Curve numbers pull the curve upwards and to the left, concentrating color resolution on lower
densities. Settings less than 1 invert the curve, moving the focus of the color range towards higher density
values. Figure 10 shows the mapping curves.
gure 10. Representative color mapping curves for the “Temperature” palette.
Fi
ng between z-axis values and color does not have to be linear. The Curve control lets you
ing the same signal shown in Figures 8 and 9, the impact of the Curve control can be observed. With
Us
the Curve control set to 1 in the Scale tab, shown in Figure 11, the mapping between color and density is
linear, so the colors spread evenly across the full density range. The color distribution is visible in the
colored palette illustration to the left of the Curve control in the Settings panel.
SPECMONB Series Printable Help 49
General Signal Viewing DPX Primer
Figure 11. Ov
When the Cur
the density range, and only the dark blues are assigned to densities below 50%. Note the difference in
the palette illustration.
Figure 12. Adjusting to values less than 1, increases the contrast for viewing events in the top half of the selected
density range.
In Figure 13, the Curve control is increased to 3. The majority of colors shifts to the lower half of the
density scale, but various shades of orange and red are still available for densities above 50%.
er a narrow Signal Density range, the color curve is set to 1.
ve control is set to 0.5, as shown in Figure 12, the best color resolution is in the upper half of
Figure 13. For color curve settings greater than 1, better contrast is provided for events near the low end of the
density range.
Swept DPX
DPX Spectrum is not limited in span by its real-time bandwidth. Like the regular Spectrum display, DPX
Spectrum steps through multiple real-time frequency segments, building a wide-span display with line
traces and the bitmap. See Figure 14.
50 SPECMONB Series Printable Help
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Figure 14. Off-air ambient signals ove r a 1 GHz span in the swept DPX display.
The analyzer “dwells” in each frequency segment for one or more DPX frames, each containing the results
of up to 14,
sweep for up to 100 seconds before moving to the next step. While dwelling in a segment, the probability
of intercept for signals within that frequency band is the same as in normal, real-time spans: 100% capture
of events as short as 10.3 μsec.
A full pixel bitmap is created for every segment and compressed horizontally to the number of columns
needed for displaying the frequency segment. Compression is done by averaging pixel densities of the
points being combined together. The final s wept bitmap contains a representation of the same pixel bitmap
resolution, just like the non-swept bitmaps. Line traces are also created in full for each segment, and then
horizo
600 spectral transforms. Dwell time is adjustable, so you can monitor each segment of the
ntally compressed to the user-selected number of trace points for the full span.
A complex algorithm for determining the number and width of each frequency segment has been
mented. The variables in the equation include user-adjustable control settings like Span, RBW, and
imple
number of trace points, RF and IF optimization, and Acquisition BW. Installed hardware options also can
affect the span segmentation. The number of segmentsrangesfrom10to50foreach1GHzinasweep.
A helpful piece of information for operators is the actual Acquisition Bandwidth used for capturing each
segment. “Acq BW” is shown in the Acquire control panel on the Sampling Parameters tab. Acq BW is
typically set automatically by the instrument, basedontheneedsofalltheopendisplays,butcanalsobe
set manua lly. In either case, the displayed bandwidth is used for every frequency segment in the swept
DPX display, though in practice, the displayed portion of the segment is somewhat narrower than the
tual Acquisition BW, for performance reasons.
ac
The entire instrument frequency range of many GHz can be covered in a DPX sweep. The Dwell Time
ontrol sets the amount of time DPX spends in each segment. This control, circled in Figure 15, can be
c
set between 50 ms and 100 seconds.
Figure 15. During swept DPX operation, the Dwell time control adjusts the observation time of each frequency
segment used to construct the composite DPX display.
SPECMONB Series Printable Help 51
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Guaranteed Capture of Fast Events
The main reason that swept-tuned and step-tuned spectrum a nalyzers can't provide 100% Probability of
Intercept, POI, for a signal that isn't continuously present is that they spend only a short period of time
tuned to each segment of their frequency span during each sweep. If something happens in any part of
the span othe
r than where it is tuned at that instant, that event will not be detected or displayed. There
is also a period of time between sweeps, retrace time, during which the analyzer is not paying attention
to the input signal. FFT-based analyzers, including vector signal analyzers, also miss signals during
the time between acquisitions. Their POI depends on a combination of factors including span, number
of FFT points, acquisition time, memory read/write time, and signal processing speed. Vector analyzers
process information sequentially, so when read/write from data and processing is occurring, data is not
being acqu
ired.
RSAs, on the other hand, capture data across all frequencies within their real-time span during every
acquisit
ion. With Tektronix' exclusive Frequency Mask trigger and DPX Density trigger, POI increases to
100%, insuring capture of any spectral event matching the trigger definition. When operating in free run as
a simple signal analyzer, the RSA has a POI similar to other FFT-based analyzers, with gaps between
each acquisition. Processing is done concurrent with the acquisitions.
Guaranteed Capture in DPX Real-Time Spans
The DPX display captures any signal that is at least 2.7 microseconds long (with Option 09) and
within the real-time bandwidth. This performance is possible because the instrument computes up to
625 spectrum transforms per second. The faster the spectrum updates, the shorter the time between
390,
acquisitions and the greater the probability that any signal will be detected.
following table shows the specified minimum signal duration (MSD) for 100% probability of intercept
The
under various combinations of Span and RBW in DPX for a representative signal analyzer. As you can
see, MSD is affected by multiple factors.
Minimum signal duration for 100% probability of trigger at 100% amplitude
Minimum signal duration, 100% probability of intercept,
equency-Mask and DPX signal processing
Fr
pan
S
165 MHz
85 MHz
RBW
(
20000 1024 390,625 15.5 15.4 2.7 2.6
10000 1024 390,625 15.6 15.4 2.8 2.6
1000 1024 390,625 17.8 15.7 5.0 2.9
300 2048 195,313 23.4 16.3 13.1 6.1
100 8192 48,828 44.5 23.4 44.5 23.4
30 32768 12,207 161.9 91.7 161.9 91.7
10000 1024 390,625 15.6 15.4 2.8 2.6
1000 1024 390,625 17.8 15.7 5.0 2.9
500 1024 390,625 20.2 15.9 7.4 3.1
300 1024 390,625 23.4 16.3 10.6 3.5
100 4096 97,656 44.5 23.4 34.2 13.2
30 16384 24,414 121.0 50.7 121.0 50.7
20 16384 24,414 161.0 55.6 161.0 55.6
FFT length
kHz)
pectrums/sec
S
Full amplitude -3 dB Full amplitude -3 dB
equency-Mask and DPX density trigger (μs)
Fr
tandard
S
pt. 09
O
52 SPECMONB Series Printable Help
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Minimum signal duration for 100% probability of trigger at 100% amplitude (cont.)
al duration, 100% probability of intercept,
Standard Opt. 09
Frequency-Mask and DPX signal processing
Span
40 MHz
25 MHz
xxx
RBW
(kHz)
5000 1024 390,625 15.8 15.4 3.0 2.6
1000 1024 390,625 17.8 15.7 5.0 2.9
300 1024 390,625 23.3 16.3 10.5 3.5
100 2048 195,313 39.4 18.3 29.1 8.1
30 4096 97,656 90.4 21.8 90.4 21.8
20 8192 48,828 140.7 36.3 140.7 36.3
10 16384 24,414 281.3 72.6 281.3 72.6
3800 1024 390,62
1000 1024 390,62
300 1024 390,62
200 1024 390,62
FFT length
Spectrums/sec
5
5
5
5
Minimum sign
Frequency-Mask and DPX density trigger (μs)
Full amplitude -3 dB Full amplitude -3 dB
16.0 15.4 3.2 2.6
17.7 15.7 4.9 2.9
23.4 16.3 10.6 3.5
27.4 16.8 14.6 4.1
To demonstrate the POI in action, a challenging bi-stable signal is used. A CW sinusoid sits at 2.4453 GHz
most of the time, but every 1.28 seconds, its frequency changes for about 100 μs before returning to
normal. The duty factor of this transient is less than 0.01%.
Figure 16 shows a swept analyzer set up for a 5-second sweep of its MaxHold trace. It shows that there is
something occurring around the signal. This sweep rate was empirically determined to be the optimum rate
for reliable capture of this signal in the shortest time. Faster sweep times can reduce the probability of
intercept and result in fewer intersections of the sweep with the signal transient.
Figure 16. Swept spectrum display of the infrequent transient.
SPECMONB Series Printable Help 53
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The DPX display shown in Figure 17 shows the exact same event, a lso captured over a 5 second period. A
lot more information can be discovered about the transient. It is obvious at first glance that the signal is
hopping by abo
Figure 17. The DPX spectrum display after 5 seconds. The MaxHold trace is cyan.
ut 3 MHz, with 1.2 MHz of frequency overshoot on transitions
Guaranteed Capture in DPX Swept Spans
Probability of intercept (POI) for signals within a single segment, while DPX is dwelling in that segment,
is the same as for non-swept DPX operation. 100% POI for events as brief as 2.7 microseconds long (with
Option 09). But just as in traditional swept analyzers, during the time the acquisition is tuned to any one
segment, the analyzer is not monitoring signals in any of the other segments, so probability of capture
in segments other than the current one is zero. Because of the wide real-time bandwidth, the number of
segments needed to cover the span is much less than for swept analyzers, so the overall probability of
intercept is significantly better for DPX sweeps.
Another factor affecting POI is number of trace points. The bitmap is always 801 points wide, but the
line traces allow user selection for number of points. 801 is the default and the other choices are 2401,
4001, and 10401. Frequency transforms for traces containing more than 801 points take longer, and this
lower waveform update rate increases the minimum signal duration proportionally. This caution applies
for swept and non-swept operation. The trace length control is on the Prefs tab in the DPX control panel.
DPX Density Measurements
“Density”isameasureofthe amount of time during a defined measurement period during which signals
are present within a particular area of the DPX Spectrum bitmap. A clean CW tone gives a 100% reading,
while a pulse that is on for one microsecond out of every millisecond reads 0.1%. This section describes
how density is computed from hit counts.
If we plot 41 more waveforms into the example grid we used previously in Figure 6 (in addition to the nine
we already plotted), each column ends with a total of 50 hits (Figure 18). The density for any one cell in a
column is its own count value divided by 50, expressed in percent as shown in Figure 19. The math is
very simple: a cell with 24 counts has a 48% density. In practice, instead of batches of 50 w aveforms, we
collect a frame of thousands of waveforms before each update to the density bitmap.
54 SPECMONB Series Printable Help
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Figure 18. Grid showing cell counts after 50 waveforms. For each column, the sum of z-axis values is 50.
e 19. Grid after converting occurrence counts to percent density values. The sums of the cell density
Figur
measurements within each column are all 100%.
Measuring Density with Markers
Hit counts are cleared after every frame update, as long as Persistence is not turned on. The density
value for any pixel is simply the percent of time it was occupied during the most recent 50 ms frame.
Markers can be used to see the Density value for one or more individual points on the screen, enabling
asurements of the signal density at any interesting point in the DPX display.
me
In Figure 20, Wireless LAN signals are analyzed in the presence of a Bluetooth radio signal in the 2.4 GHz
SM band.
I
SPECMONB Series Printable Help 55
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Figure 20. DPX display of WLAN and Bluetooth signals, with a marker on the highest signal.
The “Marker to Peak” function was used to find the peak signal recorded in the display. The marker
readout in the upper left corner of Figure 20 shows the Density, Amplitude, and Frequency for the
pixel you selected with the marker. By adding additional markers, you can measure the signal density
nces between multiple signals of interest.
differe
Marker Peak Search in the DPX Bitmap
Markers on the DPX bitmap can search for peaks, similar to marker peak searching on spectrum line
traces. For a human, it is pretty easy to discern “signals” in the bitmap picture. Your brain intuitively
identifies strings of contiguous bright pixels. This isn't so easy for a computer. The first thing the R SA
must do for any peak search is analyze pixel density values to identify apparent signals. Then it can sift
through these density peaks for the amplitude peaks you want to find.
Z-axis density values for the pixels in each column of the bitmap are internally converted into histograms
to find density peaks indicating the presence of signals. Table 2 shows the five middle columns from
example grid we used to illustrate density measurements in a previous section (Figure 19). The
the
density values for each pixel in the middle, highlighted column are plotted on the y axis in the bar chart in
Figure 21. The bar chart x axis is bitmap row number, numbering from the top of the table.
Table 2: Bitmap section showing density values.
0% 0% 0% 0% 0%
0% 0% 8% 0% 0%
0% 0% 12% 0% 0%
0% 0% 26% 0% 0%
0% 0% 36% 0% 0%
0% 2% 6% 2% 0%
4% 8% 0% 8% 0%
86% 82% 4% 76% 12%
56 SPECMONB Series Printable Help
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Table 2: Bitmap section showing density values. (cont.)
10% 8% 6% 14% 86%
0% 0% 2% 0% 2%
xxx
Figure 21. Bar chart of the density values in the bolded column of Table 2.
Assume that Density Threshold is set to 5% and Density Excursion to 5% also. Starting with x=1 in the
bar chart, test each bar against the threshold. The threshold criteria is met at x=2. Keep testing until you
find a bar that is shorter than the previous bar by at least the Excursion setting. In this case it is x=6. This
tells us that a “signal” covers rows 2 through 5. Its density peak is at row 5.
Now you can look for another peak. Continue looking at bars to the right and you will find a density
value at row 9 that meets the threshold criteria, but since there are no bars to the right of it that meet the
cursion criteria, we can't declare row 9 a signal because it fails to meet the excursion criteria. If row 1
ex
had 1% density, then row 9 would be a density peak.
nce density peaks are found for all columns in the bitmap, we can start looking for the amplitude peaks.
O
When the Peak button is selected, the analyzer checks the histograms of every column in the bitmap and
finds the density peak with the highest amplitude. The amplitude search has its own versions of Threshold
and Excursion settings, but in dBm and dB units. When Next Peak Down command is given, the search
will scan inside the current column for the next density peak. Next Peak Right examines each column to
the right of the current marker location to locate density peaks that also m eet the amplitude peak criteria.
To demonstrate the value of marker p eak search in the DPX bitmap, we will use the time-multiplexed
signals showing multiple amplitude levels from an example earlier in this manual. The Peak button
and its menu equivalent place the active marker on the peak signal in Figure 22. The p eak signal is the
density peak of highest amplitude in the bitmap.
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Figure 22. The marker was positioned by selecting the Peak button. Density, frequency, and amplitude measurements
at the marker are displayed in the upper left corner of the graph.
The Marker Toolbar, at the bottom of Figure 22, allows easy navigation of peak signals (Peak Left, Peak
Right, Next Peak Up,orNext Peak Down). Selecting the arrow keys enables the marker to search for
ude/density peaks at other frequencies, while the Next Peak Up and Next Peak Down arrows
amplit
enable the marker to search for other high-density points at the same frequency.
In the Define Peaks tab of the D efine Markers control panel, Figure 24, you can adjust the density threshold
xcursion controls to modify search behavior. The amplitude threshold and excursion controls also
and e
apply to DPX marker searches. Smoothing keeps the marker from finding multiple peaks within the same
apparent signal by averaging an adjustable number of pixel densities together, but it does not affect the
single-pixel measurement readout displayed by the marker.
Figure 24. A mplitude and Signal Density controls can be adjusted to define Peak search behavior.
Density Measurements over an Adjustable Area (“The Box”)
If you could make the box so narrow that it contained only points within a single column of p ixels, the
density of this area would be the sum of the included pixels' density values. For example, if the box was
three pixels tall and the density values for these pixels were 4, 2, and 7% respectively, the overall density
for the three-pixel area would be 13%. Imagine a box one pixel wide and as tall as the graph. Assume that
the input signal's amplitude was such that all hits fell at or near the vertical center of the screen. Since
100% of the waveforms written to the bitmap passed through the box, the density for the box is 100%.
When you widen the box to cover a broader range of frequencies, software computes the density sum for
the included pixels in each column inside the box. The aggregate density value for this box is the average
density, calculated by adding the column density sums then dividing by the number of columns. For a 100%
result, there must not be any hits above the top edge of the box or below its bottom edge. In other words,
every waveform drawn across the graph entered the box through its left side and exited the box through its
58 SPECMONB Series Printable Help
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right side, with no excursions out the top or bottom. Figure 24 demonstrates this principle on a CW signal.
As you can see on the left-hand side, no amplitudes exist above or below the box; the density of the signal
is 100%. On the
Figure 24. Density of signals defined within an area. Left: Correct measurement of a CW signal. All columns in the
box include the signal. Right: Incorrect measurement area. The measurement is accurate, but probably not what you
expected. Some columns in the box contain no hits, so they contribute zeros to the calculation of average density.
The density measurement box' vertical size and location are always set in dB and dBm, no matter wha t
units you have selected for measurements. (Amplitude control panel > Units tab.) The box is not draggable
when the selected units are linear (such as Amps, Volts, Watts…), though you can still adjust its size and
location using the Frequency and Amplitude controls in both the DPX Settings > Density and Trigger >
Event tabs. Since the vertical scale is non-linear, a box of constant amplitude changes visual height as it
changes vertical position, a disconcerting effect if you are trying to drag it.
right hand side, there are signals below the box, therefore the density is less than 100%.
Figure 25. DPX Density control p anel is used to define the area of interest for DPX density measurements.
A readout will appear somewhere in the graph. If the box is off-screen, the readout will be accompanied by
an arrow pointing towards the invisible box. Grab this readout with your mouse or finger and drag the
densityreadouttotheareayouwanttomeasure.
To adjust the box size, a mouse is the easiest way to drag the sides and corners of the rectangle. For precise
settings, use the knob, arrow keys, or keyboard to adjust frequency and amplitude values for the rectangle.
These controls are located in the right half of the Density tab in the control panel.
Persistence
Previous sections of this topic have assumed that persistence was not applied to the DPX bitmap. Without
persistence, hit counts in the grid are cleared after eac h frame update. Now we will descr ibe how
SPECMONB Series Printable Help 59
General Signal Viewing DPX Primer
persistence modifies this behavior, starting with infinite persistence because it is simpler than variable
persistence.
Hit counts are not cleared between frames if infinite persistence is enabled. When the instrument is set
up for continuous acquisitions, hits keep collecting until you stop acquisitions or click the Clear button
above the DPX
entire collection period. Density equals the total number of hits to a cell divided by the total number of
waveforms.
Variable persistence is trickier. A single-occurrence signal shown in the bitmap does not disappear
suddenly upon the next frame update, nor does it linger forever. It fades gradually away. The user sets
a time constant for the Dot Persistence control which determines how long it takes for signals to fade.
Fading is accomplished by reducing the hit count in every cell, after each frame update, by a factor based
on the persistence time constant. The longer the time constant, the less the hit counts are reduced.
display. Software keeps track of the total number of waveforms computed during the
Figure 26. Example of fast transient discovery with and without variable persistence turned on. In the display on the
left, with variable persistence of 10 seconds, the occasional sub-second transient that spikes up above the normal
signals is held in the display rather than disappearing as soon as the signal goes away. The display on the right, with
persistence turned off, requires watching the display continually to see the brief signal.
Not only are single-occurrence signals allowed to remain in the display for awhile by variable persistence,
ditional hits keep piling on. The result is that cell values are no longer pure hit counts; they include
ad
counts due to new hits from waveforms plus proportionally reduced counts from prior frames. As part
of translating hit counts into density values, a new software algorithm uses a finite-series equation to
discriminate between the effects of persistence and the arrival of new hits. The inflationary effects of
persistence on cell counts are removed, so density readings represent the true ratio of actual hits to possible
hits over the persistence interval.
The density computation for variable persistence is a very good estimate of true signal density, with errors
of less than 0.01%. For exact density measurements, use either no persistence or infinite persistence.
Another subtlety of persistence is its smoothing effect on the density measurement of intermittent signals.
Consider a pulse that is on for 10 ms and off for 90 ms of each 100 ms cycle. We'll make the simplifying
assumption that the pulse ON time a lways falls entirely within a single DPX frame update (50 ms). If
persistence is not applied, the density measurement is computed on each individual frame. The results
will be 20% for each frame containing the ON time and 0% for the other frames. If infinite persistence
is enabled, however, the density measurement will settle to 10% after the second frame, and remain at
this value for as long as the pulsing continues. With persistence, the density is effectively computed
over many frames.
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Persistence Effects on Density
Persistence does not alter colors in a density-based bitmap. Its effect is to extend the amount of time over
which densities are calculated, leaving signal events visible for the persistence duration.
Before the introduction of density measurements and extra-long hit counters, persistence caused colors
to “bloom”, becoming more and more intense over time as the hit counts increased. Longer persistence
intervals caused increased blooming, turning crisp signals into fat red stripes. When hit counts are
converted t
o density values, the display is not subject to this effect. As long as the input signals maintain
reasonably stable repetition rates and duty ratios, their density values will also remain stable despite
ever-increasing hit counts in the underlying grid cells.
If you are accustomed to the original hit-count-based persistence displays, it may seem counter-intuitive
that repeating signals in a density-based bitmap will not get brighter and redder over time with infinite
persistence. A quick review of the density algorithm explains why: the hit count is divided by the total
number of waveforms over the persistence interval. For example, if a signal occupies a pixel 50% of the
time over a period of 15 minutes, the density reading will be 50% throughout the entire 15 minutes,
though t
he underlying hit count is steadily increasing.
Z-Axis Resolution
Another factor that can cause color bloom is overflow of the hit counters. If a pixel could only count up to
1000 hits, its density and color values would clip at 100% after just 1000 hits, even if waveform points
continue to arrive in the same pixel location. With waveform points being written to the bitmap at rates
approaching 300k/sec, counts add up really fast for highly-repetitive signals. Deeper counters permit
higher hit counts, so overflow happens much later, as shown in Table 4.
Table 3: Comparison of DPX z-axis resolution and its effect on saturation.
Hit Count 36-bit custom float (equivalent to 33-bit integer)
Maximum Hit Count
Minimum Time until Over fl ow (for pixels with 100% density)
xxx
ipping due to overflow of the counters in one or more cells will not occur until hours have passed, or
Cl
8.1 hours
even days.
ne more benefit to having deeper hit counters is better visual resolution of density. RSAs with the
O
highest-performance DPX hardware installed use floating-point numbers to count hits, allowing us to count
billions of waveforms while retaining one-hit resolution, providing better than 99 dB of dynamic range
for density measurements. Density measurements in μ%, n%, and even f% ranges are quite possible for
extremely rare signals captured with infinite persistence.
With straight-line mapping between density and color (Curve setting of 1), resolution is fixed by the
number of colors in the palette. For non-linear mappings (Curve settings higher or lower than 1), most
of the colors are concentrated at either the low or high end of the density scale, so you can visually
discriminate finer differences between d ensity values in that range.
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Persistence Adjustments
Dot Persistence can be enabled for the “Bitmap” trace using the Settings control panel. The Persistence
can be displayed as Infinite or Variable. For Variable Persistence, you can select the time constant for
fading in seconds as shown in Figure 27.
Figure 27. The trace settings control panel allows user control of persistence parameters.
Figure 28 demonstrates the observed behavior of variable persistence when a CW signal, represented in
the first frame, is turned off. Even if the event was instantaneous and was confined within a single frame,
you will observe the color changing to indicate lower and lower density values, until the signal finally
disappe
ars entirely.
e 28. With variable persistence, a brief CW signal captured by DPX remains in the display for an adjustable
Figur
period of time before fading away.
DPX Density Trigger
The standard DPX display shows you a clear picture of transients and other hard-to-find signals and goes
well beyond helping you discover these difficult to find signals by actually triggering on their appearance
to capture them into acquisition memory for in-depth analysis. If you can see it in the DPX bitmap,
u can trigger on it.
yo
Other t rigger methods can detect signals that exceed an amplitude threshold, or even a sophisticated
mplitude-vs-frequency mask, but they can't find a signal at a particular frequency if another signal of
a
higher amplitude is sometimes present at that same frequency. The Runt trigger addresses some of these
signal-under-signal cases, but not all. As shown in Figure 29, the DPX Density trigger can discriminate
signals within a precise amplitude-frequency range without the operator having to know any characteristics
of the target signal besides where it might show up in the DPX Spectrum graph.
62 SPECMONB Series Printable Help
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Figure 29. Example of Density Trigger. Left: A free-run DPX display showing pulses with varying frequency.
Occasionally, a short pulse in the middle appears for a split instant, but it is hard to capture it with just a Run/Stop
button. Right: The triggered DPX displays shows the low-amplitude pulse that was not apparent in the untriggered
display. The analyzer was set to trigger whenever the average density in the user-drawn box measured 50% or higher.
The DPX Density trigger uses the same s creen-based measurement box as the DPX Density measurement.
While the
box. When the target signal finally appears, the density value increases. The trigger system monitors the
density measurement and activates a trigger whenever the density value exceeds the adjustable density
threshold. The only thinking you have to do is to set this threshold to a level somewhere between the
normal density readings and the density due to the trouble-making signal. However, the instrument
software can compute the threshold value automatically.
target signal is absent, the density measurement characterizes the “normal” signals within the
Trigger On This™
igger On This™ function allows you to point and click to set up the DPX Density trigger. By
The Tr
right-clicking on a spot within the DPX display, or pressing and holding your finger on the touchscreen
display for about a second, a menu selection will appear. Selecting Trig ger O n This causes a DPX Density
box to appear and automatically adjusts the threshold. The DPX display will now only update whenever
the automatic threshold is exceeded. Subsequently, if needed for your signal, open the Trigger control
panel to adjust the density threshold or the size of the measurement box until the event is reliably captured.
Automatic Threshold Adjustment by Trigger On This™
e trigger density threshold automatically set by Trigger On This is 80% of the measured value. If the
Th
signal was present at the moment you selected Trigger On This, the threshold will be 20% less than the
signal density, so the next time the signal is present long enough (or present enough times) to exceed
the threshold density, it will cause a trigger. If the signal happened to be missing when you selected
Trigger On This, the threshold value will be even lower. If you clicked in a part of the display with no
signal activity at all, the threshold will be set to zero. Any signal that shows up here will fire the trigger,
as shown in Figure 32.
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Figure 30. The analyzer triggered when the density in the DPX measurement box exceeded the threshold set by
Trigger On This. You can see in the Spectrogram and Frequency-vs-Time displays that the signal event which caused
the trigger was a quick frequency hop. The Time Overview shows that the signal amplitude never changed, so a
power level trigger would not have worked.
DPX Density Trigger Timing
The time resolution for DPX density measurements is the frame length, around 50 ms. A basic
implementation of the DPX Density trigger concept is also frame-based, so a trigger event that occurs
anywhere within a frame will not be recognized until the end of the frame. Therefore, the worst case
trigger uncertainty is 50 ms.
DPX Density trigger doesn't always have to wait until the end of a frame before firing. For the
common configuration of triggering when the measured density is higher than the threshold, the density
measurement in the trigger can be computed many times within each frame and it can fire the trigger
soon as the threshold is exceeded.
as
Consider the case where the threshold is zero. As soon as a single waveform causes a hit within the
easurement box, we know that the density is greater than zero. It takes a little longer to test for a 5 or
m
10% density, and even more time for thresholds at or near 100%.
The DPX Density trigger can also be set to fire when the measured density is below the threshold v alue.
This is useful when you suspect that your signal is missing some of the time. For a signal that is supposed
to be CW, you can set the trigger controls to acquire when the density measurement of the signal peak
drops below 100%. When using the “lower than” form of the DPX Density trigger, the time resolution is
64 SPECMONB Series Printable Help
General Signal Viewing DPX Display Overview
one frame because of the following logic: We can't be sure the actual density is less than, say, 15% until at
least 85% of the full test time has elapsed. In order to keep things simple and fast in the trigger module, the
RSA just waits
until the end of each 50 ms frame to do the “lower than” comparisons.
Persistence and DPX Density Trigger
The smoothing effect of persistence on density measurements can help in determining a good threshold
value. With persistence turned off, an infrequent signal's density reading jumps between higher and lower
values as it turns on and off, and it can be hard to read these flashing numbers. By turning persistence
on, you instruct the instrument to average the density over a longer time p eriod. This density result is
somewhere between the ON and OFF density values - the very definition of a good trigger threshold.
Unlike the DPX Density measurement, the DPX Density trigger is not affected in any way by persistence.
Density calculations in the trigger system are made with hit count d ata received from each individual DPX
frame, be
is averaged over many frames due to persistence, the trigger is computing density for each frame and
comparing these quick snapshots against the threshold setting.
fore any persistence is applied. Even when the density measurement reading in the display
DPX Display Overview
The DPX display enables you to see how traces change over time and thus displays signal events that
cannot be seen on a swept spectrum analyzer. A DPX Spectrum indicates how traces change in two ways.
First, it uses color shading to show how consistent the shape of a trace is. Second, it uses persistence to
hold signals on the screen so you can see them longer.
DPX Display
The DPX display works by using a two-dimensional array to represent points on the display. Each time a
trace writes to a point on the display, a counter in the array is incremented. A color is assigned to each point
in the display based on the value of its counter. Thus, as acquisitions occur over time, a colored waveform,
the Bitmap, develops on the display that shows how frequently each display point has been written to.
An important feature o f the DPX display is dot persistence. Dot persistence sets how long a point on the
display will be visible. You can set the Dot Persistence to be Variable or Infinite. In variable persistence
mode, you specify a decay period that limits how long a point will be displayed. In infinite persistence
mode, once a point in the d isplay has been w ritten to, it will remain visible indefinitely.
The DPX display can plot the trace in the following views:
Spectrum – This view plots power on the vertical axis versus frequency on the horizontal axis. This
display is similar to a standard Spectrum display.
Zero Span – This view plots power on the vertical axis versus time on the horizontal axis. This display
shows how the power level at the center frequency changes with time.
SPECMONB Series Printable Help 65
General Signal Viewing DPX Display
Frequency - This view plots frequency on the v ertical axis versus time on the horizontal axis. This
displays how frequency changes over time, where the center frequency is displayed at the center of
the vertical a
Phase - This view plots phase on the vertical axis versus time on the horizontal axis. This displays
how phase cha
the vertical axis.
xis.
nges over time, where the zero degree phase position is displayed at the center of
Split - This
and a DPX Spectrum view appears on the bottom h alf of the display.
To displ ay
1. Select Freq and use the front panel knob or number keys to set the measurement frequency.
2. Select the Displays button or Setup > Displays.ThisdisplaystheSelect Displays dialog box.
3. From the Folders box, select GeneralSignalViewing.
4. Select DPX from the Available displays box.
5. Click the Add button. This will add the DPX icon to the Selected Displays box (and remove it from
the Available displays box).
6. Click the OK button. This displays the DPX Spectrum view.
7. Selec
view consists of two DPX views. A DPXogram view appears on the top half of the display
aDPXview:
t the desired view from the drop-down list on the left side of the graph.
DPX Zero Span view
66 SPECMONB Series Printable Help
General Signal Viewing DPX Display
DPX Split View
Elements of the DPX Display
Item Display element Description
1 Vert Position
2
3RBW
dB/div Sets the vertical scale value. The maximum value is 20.00 dB/division.
Sets the top of graph value. This is only a visual control for panning the graph.
The Reference Level is adjusted in the Toolbar and the Ampl control panel. By
default, Vert Position = Ref Level.
Sets the resolution bandwidth. Note that when the RBW is set to Auto, its value is
italicized.
SPECMONB Series Printable Help 67
General Signal Viewing DPX Display
Item Display element Description
4 DPX view
5
6
7
Autoscale Adjusts the Vertical and Horizontal scaling to display the entire trace on screen.
Pos/CF Spectrum: Center Frequency - Adjusts the analyzer center frequency. For Zero
Span/Scale
, Sweep/Scale
Selects the DPX view. Choices are Spectrum, Zero Span, Frequency, Phase,
DPXogram, and
Span, Freque
Spectrum di
Split.
ncy, or Phase the Position is in seconds.
splay: Span - Adjusts frequency range of the measurement. Scale - If
Horizontal scale has been manually adjusted in Settings > Scale, then this control
adjusts the visual graph scaling without affecting the Span. Zero Span, Frequency,
Phase displ
ays: Sweep - adjusts the trace duration in s econds. Scale - adjusts the
visual graph scaling without affecting the Sweep time.
8
Clear Erases the bitmap and traces in the graph and restarts multi-trace functions
(Avg, Hold).
9 Function
10
Show Controls whether the s elected Trace is visible or not. When trace is Off, the box is
11 Trace
Readout of the Detection and Function selections for the selected trace.
not chec
Selects
ked.
a trace. Touching here pops up a context m enu listing the available
traces, whether they are enabled or not. If user selects a trace that is not currently
enabled, it will be made enabled.
xxx
Additional Elements of the DPXogram Split Display
68 SPECMONB Series Printable Help
General Signal Viewing DPX Display
Item Display element Description
1
2
3 DPXogram tr
xxx
Spectrums/line Appears only when the display is stopped. Readout of the number of spectrum
lines represe
when the Time/div or Time resolution settings are changed.
Color scale Legend at the right side of the DPX Spectrum display. This element illustrates the
relationship between the colors in the DPXogram plot and the amplitude axis of the
DPX Spectrum
and Max and Min settings on the Ampl Scale tab.
ace
The selected line in the DPXogram graph can be shown in the DPX Spectrum
graph of the Split view. The most recent DPXogram line, usually at the bottom
of the graph
determines the selected line.
nted by each line of the DPXOgram display. This value changes
plot. This scale changes with Color (DPXogram) palette selection
, is selected by default. If any markers are on, the selected marker
Time Resolution of DPXogram Display
Due to the
large amount of data produced by the DPX hardware during acquisitions, a compressed version
of the plot is shown while running. This plot is limited to 500 lines, with each line having 267 points.
However, a much longer record, with higher frequency resolution is being collected. As soon as the
instrument is stopped, this underlying data is shown, replacing the temporary version. There are 50 lines
in each vertical division of the 2-D DPXogram plot, so the time resolution of the graph is Time/div
divided by 50. However, you can set the instrument to collect multiple spectra per line, allowing you to
zoom in
later on this high-time-resolution data.
When the DPXogram display is stopped, the analyzer can display the full resolution of the captured data.
The Time Resolution readout applies only when the DPXogram is running.
Effects of Changing Time Resolution. The Time Resolution control affects acquisition parameters for the
DPX hardware. This means that if you change the Time Resolution value while the instrument is stopped,
the new value applies to the NEXT acquisition, and might not represent the results currently shown in
the display.
Time resolution can be changed either directly, by manually adjusting the Time Resolution control, or
automatically, by changing the Time/div control. Auto is the default, yielding one spectrum per line in the
display. When the Time Resolution is decreased below its auto value, multiple spectra are collected to
create ea ch line in the DPXogram graph. Once you stop the instrument, you can decrease the Time/div
value or u se Zoom to see increased time resolution.
If the time resolution is set to a very small number while the Time/div is set to a large value, you might
notice that there is a limit to the number of spectra that can be collected. This limit depends on the number
of trace points selected. For 801-point spectra, 60,000 underlying spectra can be collected. The number of
2401-point spectra collected is 20,000, and for 4001-point spectra the number is 12,000. When the limit is
reached, the oldest spectra are discarded as newer spectra are captured.
SPECMONB Series Printable Help 69
General Signal Viewing DPX Display
Touchscreen Actions on Markers in the Graph Area
Action Description
Mouse click within 1/2 div. of
amarker
Touch marker to select and
then use knob, or arrow keys
Touch and drag a marker
xxx
Selects the marker and updates the marker display to show the selected marker's values.
Adjust the setting associated with the Marker.
Changes marker position to the "drop point". You can use Tools > Options > Prefs to
change whether markers jump from one peak to the next while dragging or move smoothly
along the trace.
Available Traces for Display – Standard Instrument
Five traces can be shown in the DPX display– one bitmap and four line traces. The default traces are
Bitmap and +Peak detection. The other three traces are –Peak detection, average detection, and math.
Trace Description
Bitmap
+Peak detected
–Peak detected
Average detected
Math Trace
xxx
Displays the density of acquired data. The number of data points acquired at each pixel
(representing a particular amplitude level at a specific frequency at a point in time) is indicated
by color.
Line trace. Displays the maximum values acquired in each update. Normal and Hold functions
are available for this trace.
Line trace. Displays the minimum values acquired in each update. Normal and Hold functions
are available for this trace.
Line trace. Displays the average of all the values acquired in each update. Normal and Hold
functions are available for this trace.
Line trace. Displays the difference between two traces. The two traces used are set in the
Traces tab of the Settings panel.
Determining Which Trace Types Are Displayed
You can see the status of all the traces by selecting the Trace drop-down list. Traces that are not displayed
are preceded by "Enable". In the following figure, you can tell that the Bitmap and -Peak Trace traces are
displayed but the +Peak, Average, and Math Traces are not displayed.
Selecting Enable -Peak Trace from the Trace list displays the -Peak detected values trace.
You can see whether a trace is enabled by looking at its Show check box. The " selected trace" is selected
the Trace list. The Show check box is checked when the selected trace is enabled. To the right of the
in
70 SPECMONB Series Printable Help
General Signal Viewing DPX Display
show box are readouts for detection of the selected trace (+Pk, Avg (VRMS), ) and its function (Hold,
Normal,). You can enable/disable the selected trace by checking o r unchecking Show.
Selecting T
To select a trace for display:
1. Use the Settings control panel:
2. Select a trace from the Trace drop-down list.
races for Display – Standard Instrument
Select Setup > Settings or click the Settings button.
Select the Trac es tab.
Select the trace from the drop-down menu.
Select t
he Show check box.
cifying Ho w +Peak, –Peak, and Average Traces Are Display ed
Spe
You control how the +Peak, –Peak and Average (Avg (VRMS)) traces are displayed from the Traces tab of
Settings control panel. From the Traces tab, you ca n also specify whether these traces display results
the
from single updates or results collected over multiple updates.
change how the traces are displayed:
To
1. Select Setup > Settings or click the Settings button.
2. Select the Trac es tab.
3. Select the trace type from the drop-down list.
SPECMONB Series Printable Help 71
General Signal Viewing DPX Display
4. If you select +Peak Trace or -Peak Trace, use the Function drop-down list to select either Normal or
Hold.
a. Select Normal to set the trace to display the maximum/minimum values acquired in each
individual update.
b. Select Hold to set the trace to display the maximum/minimum values acquired over time. The
trace val ues are updated only if they exceed the existing values.
5. If you select Avg (VRMS) or Avg (of logs), use the Function drop-down list to select either Normal,
Average (VRMS),orAvg (of logs).
a. Select Normal to set the trace to display the average values acquired in each update.
b. Select Average (VRMS) or Avg (of logs) to set the trace to display an average of the average
values. Use the Count box to enter the number of times the trace is averaged.
Availab
Five traces can be shown in the DPX Spectrum, Zero Span, Frequency, and Phase displays– one bitmap
and fou
Line traces 1, 2, and 3 have user-selectable Detection and Function settings. The final line trace is Math,
allowing you to subtract one line trace from another.
For the DPXogram display, only one trace is available – the DPXogram trace.
For t
on the bottom half, you can display the Bitmap trace, Trace 1, Trace 2, Trace 3, Math trace, and Ogram
Line (the selected line from the DPXogram display) on the bottom half of the display.
le Traces for Display
r line traces. The default traces are Bitmap and Trace 1. The other three traces are 2, 3, and Math.
he Split display, which consists of a DPXogram display on the top half and a DPX Spectrum display
Selecting Traces for Display
This is done almost the same as with the standard instrument, except that the choices available for Trace
are different. Instead of +Pk, –Pk, and Avg traces, you select Trace 1, 2, and 3 and independently set the
Detection method for each of these traces to +Pk, -Pk, Avg (VRMS), or Avg (of logs).
Reference. Changing the DPX Spectrum Display Settings
(see page 306)
72 SPECMONB Series Printable Help
General Signal Viewing DPX Settings
DPX Settings
Menu Bar: Setup > Settings
Front Panel / Application Toolbar: Settings
The measurement settings for the DPX display are shown in the following table.
Settings tab
Freq & Span (see page 113) Sets frequency and span parameters for the DPX display. This tab appears for the
Params (see page 74) Sets sweep time and scroll settings. This tab appears only for the DPX Zero Span,
Freq & BW (
BW (see page 117) Sets Resolution Bandwidth.
Traces (Bitmap) Tab (see
page 75)
Traces Tab (see page 78) Allows you to select the number and types of traces to display and their functions.
Traces (Math) Tab (see
page 117)
Horiz
page 81)
Bitmap Scale Tab (see
page 82)
Amplitude Scale Tab (see
e
pag
me & Freq Scale Tab
Ti
page 84)
Prefs (see page 120) Specifies whether certain display elements are visible.
Audio Demod (see page 86) Enables and sets parameters for audio demodulation function.
xxx
see page
&VertScaleTab
83)
75)
(see
(see
Description
Spectrum and DPXogram displays.
DPX Freque
TheFreq&
Span, DPX Frequency, and DPX Phase views.
Allows you to configure the Bitmap Trace.
Allows you to configure the Math Trace.
Sets t
Sets the DPX Bitmap display parameters.
The Amplitude Scale tab allows you to change the vertical scale and offset, enable the
Waterfall display, and set the color scheme used for the DPXogram trace.
3-D
e Time and Freq Scale tab allows you to change the vertical and horizontal scale
Th
settings, number of points in the trace, and Time resolution.
ncy and DPX Phase displays.
BW tab specifies frequency and bandwidth parameters for the DPX Zero
he vertical and horizontal scale parameters for all the DPX views.
SPECMONB Series Printable Help 73
General Signal Viewing Params Tab - DPX Zero Span, DPX Frequency and DPX Phase Views
Params Tab - DPX Zero Span, DPX Frequency and DPX Phase Views
The Params tab sets the sweep time for the DPX Zero Span, Frequency and Phase views. Use the Params
tab to set the scroll mode settings for the DPX Zero Span, Frequency and Phase views. In Scroll mode,
points of the
an acquisition is completed.
Params tab settings Zero Span, Frequency and Phase views
trace are plotted as they occur, as opposed to normal mode where the trace is plotted after
Setting
Sweep time Sets the time period for the measurement. By default, the Horizontal Scale is equal to
Trace motion for Sweep
≥ 1sec
Normal
Roll
None
xxx
Description
Sweep ti
sweep time extends beyond the left and/or right edges of the graph. Range: 100 ns –
2000 s. Default: 1 ms.
Specifies how the trace is displayed when the sweep time is equal to or greater than
1seco
Selec
mode, a caret (^) moves below the graph to indicate the latest position.
Select Roll to scroll the trace as points are added at the right side of the graph. When
Roll is selected, the trace moves to the left as points are added to the trace at the right
side
Sel
me and the sweep covers 10 divisions. When the graph is zoomed in, the
nd.
t Normal to scroll the position at which data points are added to the trace. In this
of the graph.
ect None to display the trace without motion.
74 SPECMONB Series Printable Help
General Signal Viewing Freq & BW Tab - DPX Zero Span, DPX Frequency and DPX Phase Views
Freq & BW Tab - DPX Zero Span, DPX Frequency and DPX Phase Views
The Freq & BW tab specifies frequency parameters for some of the DPX display views.
Freq & BW tab settings for the bitmap trace
Setting
Center Frequency Sets the frequency at the center of the measurement bandwidth.
Step Size Sets the increment size when changing the Frequency using the knob or mouse wheel.
Auto
Measurement BW, no filter
RBW (Time-domain BW) filter RBW (Time-domain BW) is a filter used to process the input signal before the system
Actual BW
xxx
Traces Tab - Bitmap
The Traces Tab allows you to set the display characteristics of displayed traces in the DPX display. The
aces tab for the DPX display has two versions: one for the DPX Bitmap trace (described in this topic)
Tr
and one for line traces
Description
Arrow keys have an increment 10 times this setting.
When Auto is enabled, the step size is adjusted automatically based on Spectrum's
span setting.
This setting allows you to override the automatic bandwidth calculation and directly
enter a bandwidth value without the time-domain filter. If you enter a value for the
measurement bandwidth, be aware that the actual bandwidth of data provided to the
measurement will be at least as wide as the value you request and may be as much as
two times wider than requested. This override of the selected measurement bandwidth is
done so that the instrument uses sufficient bandwidth relative to the chosen symbol rate
to ensure good signal quality measurements.
analyzes the signal. The filter value determines the acquisition bandwidth that the view
requires. Range: 1 HZ to 60 MHz.
Shows the actual bandwidth being used for the display.
(see page 78).
SPECMONB Series Printable Help 75
General Signal Viewing Traces Tab - Bitmap
Traces tab – Bitmap trace
Traces tab – DPXogram trace
Traces tab settings for the bitmap trace
Setting
Trace
Show Specifies whether or not the selected trace is displayed.
Detection (DPXogram trace
only)
Intensity (standard instrument
only)
Dot Persistence
Variable The Variable dot persistence setting controls how long a point in the display is visible
Infinite The Infinite dot persistence setting prevents a point in the display from fading (not
Freeze Halts updates to the selected trace.
Save Trace As Saves the selected trace to a file for later recall and analysis.
Show Recalled Trace Displays a saved trace instead of a live trace (not available for the DPXogram trace).
xxx
Description
Select Bitmap or DPXogram to set the parameters of the DPX Bitmap or DPXogram trace.
Sets the Detection method (see page 114) used for the trace. Available detection
methods are +Peak, -Peak, and Avg (VRMS).
Use Intensity to control the visibility of events. An increased intensity l evel allows a
single, short event to be seen. This also makes such an event subject to the persistence
controls. This allows you to see the effect of the Persistence controls on infrequent
events. Range is 1-100%. Resolution: 1.
Allows a dot to remain visible if it is not updated with new data. Choices for this setting
are Variable and Infinite (not available for the D PXogram trace).
before fading (not available for the DPXogram trace).
Range: 100 ms – 60 s. Resolution 0.1.
available for the DPXogram trace).
Dot Persistence
Dot Persistence is the characteristic of the DPX display that determines how long a pixel in the display
remains visible.
To set the Persistence:
76 SPECMONB Series Printable Help
General Signal Viewing Traces Tab - Bitmap
1. Select Setup > Settings.
2. Select the Tr ace s tab.
3. Select Dot P ersistence.
4. Select either Infinite or Va r iab l e.
5. If you select Variable, enter a value in the text box. The Variable persistence value can be set from
0.05 to 100 seconds.
Saving Traces
To save a trace for later analysis:
1. Select the Save Trace As button. This displays the Save A s dialog box.
2. Navigate to the location where you want to save the file.
3. Type a name for the saved trace and click Save.
Show Recalled Trace
You can recall a previously saved trace for comparison to a live trace. First, specify a trace for recall and
second, enable Show Recalled Trace.
To select a trace for recall:
1. Select the ... button to display the Open dialog box.
SPECMONB Series Printable Help 77
General Signal Viewing Traces Tab
2. In the Open dialog, navigate to the location of the saved trace.
3. Select the desired trace file.
4. Select OK to complete your selection.
5. Select the Show recalled trace check box.
6. Verify that the trace's Show check box is selected (either on this tab or next to the drop-down list
located at the top-left corner of the graph).
Traces Tab
The Traces Tab allows you to set the display characteristics of displayed traces in the DPX display. The
Traces tab for the DPX display has two versions. One for non-Bitmap traces (described in this topic)
and one for the DPX Bitmap trace
(see page 75).
Traces tab
Setting
Trace drop-down list
Show Specifies whether or not the trace shown in the Trace setting is displayed.
Freeze Halts updates to the selected trace.
Detection
Function
Save Trace As Saves the selected trace to a file for later recall and analysis.
Show Recalled Trace Displays a saved trace instead of a live trace.
Count Enables user adjustable number of averages. This setting is only present when Function
xxx
Description
Selects which trace to configure. The available traces are B itmap, Trace 1, Trace 2,
Trace 3, and Math.
Sets the Detection method used for the trace. Available detection methods are +Peak,
-Peak, and Avg (VRMS). Not all detection methods are available in all displays.
Selects the trace processing method. Available settings are: Normal, Average, and Hold.
= Average.
Detection
Trace Detection occurs when the trace is being decimated by the measurement. For example, if the
maximum number of trace points is 100,000, and the selected analysis region is 200,000 samples, the
78 SPECMONB Series Printable Help
General Signal Viewing Traces Tab
measurement must decimate the 200,000 resulting trace points by 2 to prevent exceeding the 100,000 trace
point limit. Since only one value can be selected for each trace point, an algorithm must be used to select
(detect) the a
ppropriate value to use.
The available detection methods are:
+Peak – Each point on the trace is the result of detecting the positive peak value present in the set of
IQ samples available to that trace point.
-Peak – Each point on the trace is the result of detecting the negative peak value present in the set of
IQ samples available to that trace point.
Avg (VR MS) [Average V
] – Each point on the trace is the result of determining the RMS Voltage
RMS
value for all of the IQ samples available to the trace point. When displayed in either linear (Volts,
Watts) or
Log (dB, dBm), the correct RMS value results. When the averaging f unction is applied to a
trace, the averaging is performed on the linear (Voltage) values, resulting in the correct average
for RMS values.
NOTE. The Detection setting does not affect the trace until the spectrum length is longer than the Auto
setting.
DPX Tr
ace Processing
The +Peak, -Peak, and Average traces can be processed to display in different ways. The Function setting
ols trace processing.
contr
Hold - Displays the value in the trace record for each display point. Each new trace display point is
ared to the previous maximum value and the greater value is retained for display and subsequent
comp
comparisons. Available for traces using +Peak or -Peak detection.
mal - Displays the trace record for each display point without additional processing. Available
Nor
for all detection selections.
erage - Default setting for the Average. Multiple traces are averaged together to g enerate the
Av
displayed trace. There is one vertical value for each underlying frequency data point. Once the
specified number of traces have been acquired and averaged to generate the displayed trace, each new
trace takes the place of the oldest trace in the calculation. The Count setting specifies how many
traces are averaged. Available for traces using Average detection.
Trace averaging uses the exponential method. If Count = 10, the newest trace's contribution to the
averaged trace is 10%. When Count is not checked, the algorithm assumes the maximum number of
traces contributing to the average is
.
Saving Traces
To save a trace for later analysis:
1. Select the Save Trace As button. This displays the Save A s dialog box.
SPECMONB Series Printable Help 79
General Signal Viewing Traces Tab
2. Type a name
for the saved trace and click Save.
Recalling Traces
You can recall a previously saved trace for comparison to a live trace. First, specify a trace for recall and
second, enable Show Recalled Trace.
To select a trace for recall:
1. Click t
2. Navigate to the desired file and click Open.
3. Check the Show Recalled Trace check box.
4. Verify that the trace's Show check box is selected (either on this tab or next to the drop-down list
he ... button to display the Open dialog box.
located at the top-left corner of the graph).
80 SPECMONB Series Printable Help
General Signal Viewing Horiz & Vert Scale Tab
Horiz & Vert Scale Tab
The Horiz & Vert Scale tab allows you to change the vertical scale settings used for the Bitmap trace.
Changing the scale settings changes how the trace appears on the display but does not change control
settings suc
h as Measurement Frequency.
Setting
Vertical
Description
Controls the vertical position and scale of the trace display.
Scale Changes the vertical scale.
Offset Adjusts the Reference Level away from the top of the trace display.
Reset Scale Sets Scale to its default value and Offset to zero. Disabled when Units (Setup > Analysis
> Units) is set to Watts or Volts.
Autoscale
Resets the scale of the vertical axis to contain the complete trace. Disabled when Units
(Setup > Analysis > Units) i s set to Watts or Volts.
Horizontal
Controls the horizontal position and scale of the trace display.
Scale Changes the horizontal scale.
x
xx
Position
Autoscale
Adjusts the horizontal position of the signal. This does not change the center frequency.
Resets the scale of the horizontal axis to contain the complete trace.
SPECMONB Series Printable Help 81
General Signal Viewing Bitmap Scale Tab
Bitmap Scale Tab
The Bitmap Scale tab allows you to set the color scheme used for the Bitmap trace. Changing the DPX
bitmap Color, Max and Min scale settings changes how the trace appears on the display but does not
change contr
ol settings such as Measurement Frequency.
Setting
DPX Bitma
Curve Adjus
Auto
xxx
p (Signal Density)
Color Allows y
Max
Min
Color
Description
Controls
Sets the
densities greater than this value.
Range: 1p% - 100%; Default: 100%.
Sets the hit density represented by the bottom of the color range. Range: 0 - 80%;
Defau
= 1), or it can be set to concentrate the resolution on the lower level of the range (Curve >
1) or the mapping can be set to show the best resolution on the upper range of density
or hi
Adju
the appearance and scale of the DPX Bitmap trace.
ou to select the color palette used for the DPX Bitmap trace.
hit density represented by the top of the color scale. "Clipping" occurs for
lt: 0.
ts how colors are mapped to the signal density. The mapping can be linear (Curve
t count (Curve < 1).
sts the Max and Min settings to display the broadest range of colors.
82 SPECMONB Series Printable Help
General Signal Viewing Amplitude Scale Tab
Amplitude Scale Tab
The Amplitude Scale tab allows you to change the vertical and horizontal scale settings, enable the 3-D
Waterfall display, and set the color sc heme used for the DPXogram trace.
Setting
Height
Description
Height controls apply only to the 3-D Waterfall display.
Scale Changes the vertical scale for trace Amplitude in the graph (not the vertical scale for
Time).
Position
Specifies the level displayed at the bottom edge of the graph. (Bottom front edge in
the 3-D view).
Autoscale
Adjusts the vertical position bottom for linear units like Amps and Volts. Adjust the vertical
position top for log units like dBm. dBm is the default.
3-D Waterfall Displays the DPXogram in a 3-D format.
Northeast
Shifts the perspective of the 3-D graph so that the oldest traces move back and to the
right.
Northwest
Shifts the perspective of the 3-D graph so that the oldest traces move back and to the left.
Reset Scale Resets the Height and Color settings to their default values.
Color (DPXogram)
Color Displays a drop-down list that allows you to set the color scheme used for the DPXogram
trace.
Max
Min
xx
x
Sets the power level represented by the top of the color scale.
Sets the power level represented by the bottom of the color scale.
SPECMONB Series Printable Help 83
General Signal Viewing Time & Freq Scale Tab
Time & Freq Scale Tab
The Time and Freq Scale tab allows you to change the vertical and horizontal scale settings, set the time
resolution and number of trace points of the DPXogram display.
Setting
Vertical (time)
Time/div For most Spectrogram applications. Primary time scale control is Time/div. Time
Position
Time at position
Reset Scale Sets the Time/div and Position settings to their default values.
Trace Points
Time resolution
Auto
Capacity Readout of the total length of time that can be captured. This readout is provided
Horizontal (frequency)
Scale Sets the displayed frequency range of the graph. This control affects only visual
Position
Autoscale
xxx
Description
scale can be zoomed in or out when acquisitions are stopped.
The position of the DPXOgram record at the bottom of the display. Position cannot
be changed while acquisitions are active, and is reset to zero when acquisitions
are started again.
Displays the time of the DPXogram line shown at the bottom of the graph. This time
is relative to the Time Zero Reference of the current acquisition. If Position is set to a
negative value, the Time at position readout will be blanked.
Sets the number of trace points computed for each DPXogram line. These are the
points used for marker measurements and for results export.
Specifies the length of time represented by each line in the graph.
Sets the time represented by each line in the graph to be adjusted by the analyzer
checked) or manually (when unchecked). When Auto is enabled, Time Resolution
change based on Time/div.
so that you can see how changing the Trace Points and Time resolution affects
the amount of data that can be captured. Capacity is represented in the format
dd:hh:mm:ss.
scaling, and does not change the acquisition or analysis parameters.
Sets the frequency displayed at the center of the graph. Changing this value does
not change the Frequency setting.
Sets the frequency scale to the Spectrogram Span value.
84 SPECMONB Series Printable Help
General Signal Viewing Density Tab
Density Tab
The Density tab specifies the parameters of the measurement box used for measuring average signal
density of an area in the bitmap. The measurement box is also used by DPX Density triggering.
To measure the average signal density over a rectangular portion of the DPX bitmap, you c
an adjust the
size and location of the measurement area using these controls, or by dragging the measurement box in
the graph. You move the box by dragging the readout. You adjust the size of the box by dragging the
corners or edges.
Setting
Show Measurement Shows or hides the measurement box in the graph when Triggering is not set to DPX
Frequency
Amplitude
xxx
Description
Density. If Triggering is set to DPX Density, the measurement box is always visible.
Specifies the frequency at the center of the measurement box. The +/- value specifies
the width of the measurement box.
Specifies the amplitude of the center of the measurement box. The +/- value specifies
the height of the measurement box.
SPECMONB Series Printable Help 85
General Signal Viewing Audio Demod Tab
Audio Demod Tab
Audio demodulation can help you identify unknown radio signals. You control the audio demodulation
function with the Audio Demod tab. You access the Audio Demod tab from the Settings control panel of
the DPX displ
NOTE. Audio Demodulation is available only in real-time acquisition mode (not swept acquisition), and
the Trigger mode must be set to Free Run (not Triggered).
ay.
Setting
On/Off Enables/disables audio demodulation.
Audio Gain Adjusts the volume of the demodulated audio.
AM
FM
Tune with
Receiver Freq
Receiver BW
xxx
Description
Selects Amplitude Modulation as the demodulation method.
Selects Frequency Modulation as the demodulation method.
Specifies how the frequency to be demodulated is specified. You can select markers
or the frequency control.
Readout of the frequency to be demodulated.
Adjusts the equivalent receiver bandwidth for the audio demodulation. The range of
values is 1 kHz to 500 kHz.
AM / FM
Note that these buttons select the demodulation method; they do not specify a frequency band.
Tune with
The choices for this setting are: one of the m arkers (MR, M1, M2, M3, M4) or the Frequency control
(either the front-panel knob or the Freq control in the application).
To use a marker to specify the frequency to be demodulated:
1. Select Markers > Define Markers to display the Define Markers control panel.
2. Select Add to turn on the next marker.
86 SPECMONB Series Printable Help
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