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R&S®FSV3-K70
Vector Signal Analysis
User Manual
(;Üëâ2)
1178938402
Version 08
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This manual applies to the following R&S®FSV3000 and R&S®FSVA3000 models with firmware version
1.70 and higher:
●
R&S®FSV3004 (1330.5000K04) / R&S®FSVA3004 (1330.5000K05)
●
R&S®FSV3007 (1330.5000K07) / R&S®FSVA3007 (1330.5000K08)
●
R&S®FSV3013 (1330.5000K13) / R&S®FSVA3013 (1330.5000K14)
●
R&S®FSV3030 (1330.5000K30) / R&S®FSVA3030 (1330.5000K31)
●
R&S®FSV3044 (1330.5000K43) / R&S®FSVA3044 (1330.5000K44)
The following firmware options are described:
●
R&S FSV/A-K70 (1330.5074.02)
●
R&S FSV/A-K70P (1346.3382.02)
●
R&S FSV/A-K70M (1346.3376.02)
© 2022 Rohde & Schwarz GmbH & Co. KG
Muehldorfstr. 15, 81671 Muenchen, Germany
Phone: +49 89 41 29 - 0
Email: info@rohde-schwarz.com
Internet: www.rohde-schwarz.com
Subject to change – data without tolerance limits is not binding.
R&S® is a registered trademark of Rohde & Schwarz GmbH & Co. KG.
Trade names are trademarks of the owners.
1178.9384.02 | Version 08 | R&S®FSV3-K70
Throughout this manual, products from Rohde & Schwarz are indicated without the ® symbol, e.g. R&S®FSV3 is indicated as
R&S FSV3. R&S®SMW200A is indicated as R&S SMW200A.
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R&S®FSV3-K70
1 Documentation overview.....................................................................13
1.1 Getting started manual............................................................................................... 13
1.2 User manuals and help...............................................................................................13
1.3 Service manual............................................................................................................13
1.4 Instrument security procedures................................................................................ 14
1.5 Printed safety instructions.........................................................................................14
1.6 Data sheets and brochures........................................................................................ 14
1.7 Release notes and open-source acknowledgment (OSA).......................................14
1.8 Application notes, application cards, white papers, etc......................................... 15
2 Welcome to the R&S FSV3 VSA application......................................16
Contents
Contents
2.1 Introduction to vector signal analysis...................................................................... 17
2.2 Starting the VSA application......................................................................................18
2.3 Understanding the display information.................................................................... 18
3 Measurements and result displays.................................................... 21
3.1 Evaluation data sources in VSA................................................................................ 21
3.2 Result types in VSA.................................................................................................... 25
3.2.1 Bit error rate (BER)....................................................................................................... 27
3.2.2 Channel frequency response group delay.................................................................... 29
3.2.3 Channel frequency response magnitude...................................................................... 30
3.2.4 Constellation frequency.................................................................................................31
3.2.5 Constellation I/Q............................................................................................................31
3.2.6 Constellation I/Q (rotated)............................................................................................. 33
3.2.7 Error vector magnitude (EVM)...................................................................................... 34
3.2.8 Eye diagram frequency................................................................................................. 35
3.2.9 Eye diagram imag (Q)................................................................................................... 36
3.2.10 Eye diagram real (I).......................................................................................................38
3.2.11 Frequency absolute.......................................................................................................39
3.2.12 Frequency relative.........................................................................................................40
3.2.13 Frequency error absolute.............................................................................................. 41
3.2.14 Frequency error relative................................................................................................ 43
3.2.15 Frequency response group delay..................................................................................44
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3.2.16 Frequency response magnitude....................................................................................45
3.2.17 Frequency response phase...........................................................................................45
3.2.18 Impulse response magnitude........................................................................................ 46
3.2.19 Impulse response phase............................................................................................... 47
3.2.20 Impulse response real/imag.......................................................................................... 48
3.2.21 Magnitude absolute.......................................................................................................48
3.2.22 Magnitude overview (capture buffer).............................................................................50
3.2.23 Magnitude relative.........................................................................................................51
3.2.24 Magnitude error.............................................................................................................52
3.2.25 Phase error................................................................................................................... 53
3.2.26 Phase wrap................................................................................................................... 54
3.2.27 Phase unwrap............................................................................................................... 55
3.2.28 Real/imag (I/Q)..............................................................................................................56
Contents
3.2.29 Result summary............................................................................................................ 57
3.2.30 Spectrum (capture buffer + error)..................................................................................60
3.2.31 Spectrum (measurement + error)..................................................................................62
3.2.32 Symbol table................................................................................................................. 63
3.2.33 Vector frequency........................................................................................................... 65
3.2.34 Vector I/Q...................................................................................................................... 65
3.3 Predefined display configuration.............................................................................. 67
3.4 Common parameters in VSA......................................................................................68
4 Measurement basics............................................................................70
4.1 Filters and bandwidths during signal processing................................................... 70
4.1.1 I/Q bandwidth................................................................................................................ 71
4.1.2 Demodulation bandwidth (measurement bandwidth)....................................................72
4.1.3 Modulation and demodulation filters............................................................................. 72
4.1.4 Measurement filters.......................................................................................................73
4.1.5 Customized filters..........................................................................................................75
4.2 Sample rate, symbol rate and I/Q bandwidth........................................................... 77
4.2.1 Sample rate and maximum usable I/Q bandwidth for RF input.....................................78
4.2.1.1 Bandwidth extension options........................................................................................ 79
4.2.1.2 Relationship between sample rate, record length and usable I/Q bandwidth............... 79
4.2.1.3 R&S FSV/A without additional bandwidth extension options........................................ 80
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4.2.1.4 R&S FSV/A with I/Q bandwidth extension option B40 or U40...................................... 81
4.2.1.5 R&S FSV/A with I/Q bandwidth extension option B200................................................ 81
4.2.1.6 R&S FSV/A with I/Q bandwidth extension option B400................................................ 81
4.2.1.7 R&S FSV/A with I/Q bandwidth extension option B600................................................ 82
4.2.1.8 R&S FSV/A with I/Q bandwidth extension option B1000.............................................. 82
4.3 Symbol mapping......................................................................................................... 82
4.3.1 Phase shift keying (PSK).............................................................................................. 83
4.3.2 Rotating PSK.................................................................................................................87
4.3.3 Differential PSK.............................................................................................................90
4.3.4 Rotating differential PSK modulation.............................................................................91
4.3.5 Offset QPSK..................................................................................................................93
4.3.6 Shaped offset QPSK..................................................................................................... 94
4.3.7 Frequency shift keying (FSK)........................................................................................95
Contents
4.3.8 Minimum shift keying (MSK)....................................................................................... 100
4.3.9 Quadrature amplitude modulation (QAM)................................................................... 101
4.3.10 ASK............................................................................................................................. 113
4.3.11 APSK...........................................................................................................................114
4.3.12 User-defined modulation............................................................................................. 115
4.4 Overview of the demodulation process.................................................................. 116
4.4.1 Burst search................................................................................................................ 119
4.4.2 I/Q pattern search....................................................................................................... 120
4.4.3 Demodulation and symbol decisions...........................................................................121
4.4.4 Pattern symbol check..................................................................................................124
4.4.5 Synchronization and the reference signal................................................................... 125
4.4.6 The equalizer.............................................................................................................. 127
4.5 Signal model, estimation and modulation errors...................................................129
4.5.1 PSK, QAM and MSK modulation................................................................................ 130
4.5.1.1 Error model................................................................................................................. 130
4.5.1.2 Estimation................................................................................................................... 131
4.5.1.3 Modulation errors........................................................................................................ 132
4.5.2 FSK modulation...........................................................................................................141
4.5.2.1 Error model................................................................................................................. 143
4.5.2.2 Estimation................................................................................................................... 144
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4.5.2.3 Modulation errors........................................................................................................ 145
4.6 Measurement ranges................................................................................................ 146
4.6.1 Result range................................................................................................................147
4.6.2 Evaluation range......................................................................................................... 149
4.7 Display points vs estimation points per symbol....................................................151
4.8 Capture buffer display.............................................................................................. 152
4.9 Known data files - dependencies and restrictions................................................ 154
4.10 Known data from PRBS generators........................................................................ 155
4.11 Multi-modulation analysis (R&S FSV/A-K70M).......................................................157
4.12 I/Q data import and export....................................................................................... 163
5 Configuration......................................................................................164
5.1 Configuration overview............................................................................................ 164
Contents
5.2 Configuration according to digital standards........................................................ 168
5.3 Signal description..................................................................................................... 170
5.3.1 Modulation...................................................................................................................170
5.3.2 Signal structure........................................................................................................... 174
5.3.3 Frame structure...........................................................................................................177
5.3.3.1 General frame structure settings.................................................................................177
5.3.3.2 Frame configuration.................................................................................................... 180
5.3.4 Known data................................................................................................................. 185
5.4 Input, output and frontend settings.........................................................................188
5.4.1 Input settings...............................................................................................................188
5.4.1.1 Radio frequency input................................................................................................. 189
5.4.1.2 Settings for input from I/Q data files............................................................................192
5.4.2 Output settings............................................................................................................ 194
5.4.3 Frequency settings......................................................................................................196
5.4.4 Amplitude and vertical axis configuration....................................................................198
5.4.4.1 Amplitude settings.......................................................................................................198
5.4.4.2 Scaling........................................................................................................................ 203
5.4.4.3 Units............................................................................................................................ 206
5.5 Signal capture........................................................................................................... 207
5.5.1 Data acquisition...........................................................................................................207
5.5.2 Trigger settings............................................................................................................209
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5.5.3 Sweep settings............................................................................................................214
5.6 Burst and pattern configuration.............................................................................. 216
5.6.1 Burst search................................................................................................................ 216
5.6.2 Pattern search.............................................................................................................218
5.6.3 Pattern configuration................................................................................................... 220
5.6.4 Pattern definition......................................................................................................... 223
5.7 Result range configuration...................................................................................... 226
5.8 Demodulation settings............................................................................................. 228
5.8.1 Demodulation - compensation and equalizer..............................................................228
5.8.2 Advanced demodulation (synchronization)................................................................. 232
5.9 Measurement filter settings..................................................................................... 236
5.10 Evaluation range configuration............................................................................... 237
5.11 Adjusting settings automatically.............................................................................239
Contents
5.12 Restoring factory settings for vector signal analysis........................................... 241
6 Analysis.............................................................................................. 242
6.1 Trace settings............................................................................................................242
6.2 Trace export settings................................................................................................246
6.3 Markers...................................................................................................................... 248
6.3.1 Individual marker settings........................................................................................... 249
6.3.2 Marker search settings................................................................................................250
6.3.3 Marker positioning functions....................................................................................... 252
6.4 Limit and display lines..............................................................................................253
6.4.1 Display lines for eye diagrams.................................................................................... 253
6.4.2 Modulation accuracy limit lines................................................................................... 254
6.5 Display and window configuration..........................................................................257
6.5.1 Result window configuration....................................................................................... 257
7 How to perform vector signal analysis............................................ 262
7.1 How to perform VSA according to digital standards.............................................262
7.2 How to perform customized VSA measurements.................................................. 264
7.2.1 How to define the result range.................................................................................... 265
7.2.2 How to select user-defined filters................................................................................ 266
7.2.3 How to perform pattern searches................................................................................267
7.2.3.1 How to assign patterns to a standard..........................................................................268
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7.2.3.2 How to define a new pattern....................................................................................... 268
7.2.3.3 How to manage patterns............................................................................................. 271
7.2.4 How to work with known data files.............................................................................. 272
7.2.4.1 How to load known data files...................................................................................... 273
7.2.4.2 How to create known data files................................................................................... 273
7.2.5 How to work with PRBS as known data...................................................................... 275
7.3 How to analyze the measured data......................................................................... 276
7.3.1 How to change the display scaling..............................................................................277
7.3.1.1 How to scale time and spectrum diagrams................................................................. 277
7.3.1.2 How to scale statistics diagrams................................................................................. 278
7.3.2 How to measure the size of an eye.............................................................................280
7.3.3 How to check limits for modulation accuracy.............................................................. 281
7.3.4 How to export the trace data to a file.......................................................................... 282
Contents
8 Measurement examples.....................................................................283
8.1 Connecting the transmitter and analyzer............................................................... 283
8.2 Measurement example 1: continuous QPSK signal.............................................. 284
8.2.1 Transmitter settings.....................................................................................................284
8.2.2 Analyzer settings.........................................................................................................285
8.2.3 Changing the display configuration............................................................................. 286
8.2.4 Navigating through the capture buffer.........................................................................287
8.2.5 Averaging several evaluations.................................................................................... 288
8.3 Measurement example 2: burst GSM EDGE signals..............................................289
8.3.1 Transmitter settings.....................................................................................................289
8.3.2 Analyzer settings.........................................................................................................291
8.3.3 Navigating through the capture buffer.........................................................................292
8.3.4 Evaluating the rising and falling edges........................................................................293
8.3.5 Setting the evaluation range....................................................................................... 294
8.3.6 Comparing the measurement signal to the reference signal.......................................295
9 Troubleshooting the measurement.................................................. 297
9.1 Flow chart for troubleshooting................................................................................ 297
9.2 Explanation of status bar messages.......................................................................299
9.3 Frequently asked questions.....................................................................................308
9.3.1 Issues with graphical results....................................................................................... 308
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9.3.2 Issues with numeric results......................................................................................... 313
9.3.3 Synchronization and demodulation problems............................................................. 317
9.3.4 Other measurement issues......................................................................................... 318
10 Remote commands for VSA..............................................................320
10.1 Introduction............................................................................................................... 320
10.1.1 Conventions used in descriptions............................................................................... 321
10.1.2 Long and short form.................................................................................................... 322
10.1.3 Numeric suffixes..........................................................................................................322
10.1.4 Optional keywords.......................................................................................................322
10.1.5 Alternative keywords................................................................................................... 323
10.1.6 SCPI parameters.........................................................................................................323
10.1.6.1 Numeric values........................................................................................................... 323
Contents
10.1.6.2 Boolean....................................................................................................................... 324
10.1.6.3 Character data............................................................................................................ 324
10.1.6.4 Character strings.........................................................................................................325
10.1.6.5 Block data................................................................................................................... 325
10.2 Common suffixes...................................................................................................... 325
10.3 Activating vector signal analysis............................................................................ 325
10.4 Digital standards....................................................................................................... 329
10.5 Configuring VSA....................................................................................................... 331
10.5.1 Signal description........................................................................................................332
10.5.1.1 Modulation...................................................................................................................332
10.5.1.2 Signal structure........................................................................................................... 341
10.5.1.3 Frame structure...........................................................................................................344
10.5.1.4 Known data................................................................................................................. 355
10.5.2 Input, output and frontend settings..............................................................................359
10.5.2.1 RF input.......................................................................................................................359
10.5.2.2 Configuring file input................................................................................................... 362
10.5.2.3 Using external mixers..................................................................................................363
Basic settings.............................................................................................................. 363
Mixer settings.............................................................................................................. 365
Conversion loss table settings.................................................................................... 371
Programming example: working with an external mixer..............................................375
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10.5.2.4 Remote commands for external frontend control........................................................ 377
10.5.2.5 Output settings............................................................................................................ 392
10.5.2.6 Configuring the trigger output......................................................................................393
10.5.2.7 Frequency................................................................................................................... 395
10.5.2.8 Amplitude settings.......................................................................................................397
10.5.2.9 Scaling and units.........................................................................................................403
10.5.3 Signal capture............................................................................................................. 409
10.5.4 Triggering measurements........................................................................................... 413
10.5.5 Configuring sweeps.....................................................................................................417
Contents
Commands for initial configuration..............................................................................377
Commands for test, alignment, and diagnosis............................................................ 384
Format of selftest result file......................................................................................... 386
Programming example: configuring an external frontend........................................... 391
10.5.6 Configuring bursts and patterns.................................................................................. 419
10.5.6.1 Burst search................................................................................................................ 419
10.5.6.2 Pattern searches......................................................................................................... 421
10.5.6.3 Configuring patterns....................................................................................................423
10.5.7 Defining the result range............................................................................................. 426
10.5.8 Demodulation settings.................................................................................................429
10.5.9 Measurement filter settings......................................................................................... 438
10.5.10 Defining the evaluation range..................................................................................... 440
10.5.11 Adjusting settings automatically.................................................................................. 441
10.6 Performing a measurement......................................................................................444
10.7 Analysis..................................................................................................................... 448
10.7.1 Configuring traces....................................................................................................... 448
10.7.2 Working with markers..................................................................................................452
10.7.2.1 Individual marker settings........................................................................................... 452
10.7.2.2 Marker search and positioning settings.......................................................................457
10.7.3 Configuring display lines for eye diagrams................................................................. 464
10.7.4 Configuring modulation accuracy limit lines................................................................ 468
10.7.4.1 General commands.....................................................................................................469
10.7.4.2 Defining limits..............................................................................................................469
10.8 Configuring the result display................................................................................. 474
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10.8.1 General window commands........................................................................................474
10.8.2 Working with windows in the display...........................................................................476
10.8.3 VSA window configuration.......................................................................................... 482
10.9 Retrieving results......................................................................................................490
10.9.1 Retrieving trace data and marker values.................................................................... 490
10.9.2 Measurement results for TRACe<n>[:DATA]? TRACE<n>.........................................496
10.9.2.1 Capture buffer results..................................................................................................496
10.9.2.2 Cartesian diagrams..................................................................................................... 496
10.9.2.3 Polar diagrams............................................................................................................ 497
10.9.2.4 Symbols...................................................................................................................... 497
10.9.2.5 Result summary.......................................................................................................... 497
10.9.2.6 Equalizer..................................................................................................................... 498
10.9.2.7 Multi source.................................................................................................................498
Contents
10.9.3 Retrieving general burst and pattern information........................................................ 498
10.9.4 Retrieving parameter values....................................................................................... 503
10.9.5 Retrieving limit check results.......................................................................................518
10.10 Importing and exporting I/Q data and results........................................................ 520
10.11 Status reporting system...........................................................................................521
10.11.1 STATus:QUEStionable:SYNC<n> register..................................................................524
10.11.2 STATus:QUEStionable:MODulation<n> register.........................................................524
10.11.3 STATus:QUESTionable:MODulation<n>:EVM register............................................... 524
10.11.4 STATus:QUESTionable:MODulation<n>:PHASe register........................................... 525
10.11.5 STATus:QUESTionable:MODulation<n>:MAGnitude register.....................................525
10.11.6 STATus:QUESTionable:MODulation<n>:CFRequency register..................................526
10.11.7 STATus:QUESTionable:MODulation<n>:IQRHO register........................................... 526
10.11.8 STATus:QUESTionable:MODulation<n>:FSK register................................................527
10.11.9 Querying the status registers...................................................................................... 527
10.12 Deprecated commands.............................................................................................532
10.13 Programming examples........................................................................................... 533
10.13.1 Measurement example 1: user-defined measurement of continuous QPSK signal....534
10.13.2 Measurement example 2: GSM EDGE burst measurement based on a digital standard
.................................................................................................................................... 536
10.13.3 Measurement example 3: user-defined pattern search and limit check......................539
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A Abbreviations..................................................................................... 542
B Predefined standards and settings.................................................. 543
C Predefined measurement and tx filters............................................552
C.1 Transmit filters.......................................................................................................... 552
C.2 Measurement filters.................................................................................................. 553
C.3 Typical combinations of tx and measurement filters.............................................554
D ASCII file export format for VSA data...............................................555
E Known data file syntax description..................................................557
F Formulae.............................................................................................559
F.1 Trace-based evaluations.......................................................................................... 559
Contents
Annex.................................................................................................. 542
F.2 Result summary evaluations................................................................................... 561
F.2.1 PSK, QAM and MSK modulation................................................................................ 561
F.2.2 FSK modulation...........................................................................................................563
F.3 Statistical evaluations for the result summary...................................................... 564
F.4 Trace averaging.........................................................................................................564
F.5 Analytically calculated filters................................................................................... 565
F.6 Standard-specific filters........................................................................................... 566
F.6.1 Transmit filter...............................................................................................................566
F.6.2 Measurement filter...................................................................................................... 566
F.6.2.1 EDGE measurement filters......................................................................................... 566
F.6.2.2 Low-isi filters............................................................................................................... 569
List of Commands (VSA)...................................................................573
Index....................................................................................................585
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R&S®FSV3-K70
1 Documentation overview
1.1 Getting started manual
Documentation overview
Service manual
This section provides an overview of the R&S FSV/A user documentation. Unless
specified otherwise, you find the documents on the R&S FSV/A product page at:
www.rohde-schwarz.com/product/FSVA3000.html/
www.rohde-schwarz.com/product/FSV3000.html
Introduces the R&S FSV/A and describes how to set up and start working with the
product. Includes basic operations, typical measurement examples, and general information, e.g. safety instructions, etc.
A printed version is delivered with the instrument. A PDF version is available for download on the Internet.
1.2 User manuals and help
Separate user manuals are provided for the base unit and the firmware applications:
●
Base unit manual
Contains the description of all instrument modes and functions. It also provides an
introduction to remote control, a complete description of the remote control commands with programming examples, and information on maintenance, instrument
interfaces and error messages. Includes the contents of the getting started manual.
●
Firmware application manual
Contains the description of the specific functions of a firmware application, including remote control commands. Basic information on operating the R&S FSV/A is
not included.
The contents of the user manuals are available as help in the R&S FSV/A. The help
offers quick, context-sensitive access to the complete information for the base unit and
the firmware applications.
All user manuals are also available for download or for immediate display on the Internet.
1.3 Service manual
Describes the performance test for checking the rated specifications, module replacement and repair, firmware update, troubleshooting and fault elimination, and contains
mechanical drawings and spare part lists.
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1.4 Instrument security procedures
1.5 Printed safety instructions
Documentation overview
Release notes and open-source acknowledgment (OSA)
The service manual is available for registered users on the global Rohde & Schwarz
information system (GLORIS):
R&S®FSVA3000/FSV3000 Service manual
Deals with security issues when working with the R&S FSV/A in secure areas. It is
available for download on the Internet.
Provides safety information in many languages. The printed document is delivered with
the product.
1.6 Data sheets and brochures
The data sheet contains the technical specifications of the R&S FSV/A. It also lists the
firmware applications and their order numbers, and optional accessories.
The brochure provides an overview of the instrument and deals with the specific characteristics.
See www.rohde-schwarz.com/brochure-datasheet/FSV3000 /
www.rohde-schwarz.com/brochure-datasheet/FSVA3000
1.7 Release notes and open-source acknowledgment (OSA)
The release notes list new features, improvements and known issues of the current
firmware version, and describe the firmware installation.
The open-source acknowledgment document provides verbatim license texts of the
used open source software.
See www.rohde-schwarz.com/firmware/FSV3000 /
www.rohde-schwarz.com/firmware/FSVA3000
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1.8 Application notes, application cards, white papers,
Documentation overview
Application notes, application cards, white papers, etc.
etc.
These documents deal with special applications or background information on particular topics.
See www.rohde-schwarz.com/application/FSV3000 /
www.rohde-schwarz.com/application/FSVA3000
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R&S®FSV3-K70
2 Welcome to the R&S FSV3 VSA application
Welcome to the R&S FSV3 VSA application
The R&S FSV3-K70 is a firmware application that adds functionality to perform vector
signal analysis (VSA) to the R&S FSV/A.
The R&S FSV3 VSA application performs vector and scalar measurements on digitally
modulated single-carrier signals. To perform the measurements, it converts RF signals
into the complex baseband. The R&S FSV3 VSA application can also use the optional
"Digital Baseband" interface or the optional "Analog Baseband" interface to analyze I/Q
signals already delivered to the complex baseband.
Use of an optional external mixer is also supported.
Use of an optional external frontend is also supported.
The R&S FSV3 VSA application features:
●
Flexible modulation analysis from MSK to 1024QAM
●
Numerous standard-specific default settings
●
Various graphical, numerical and statistical evaluations and result displays
●
Spectrum analyses of the measurement and error signal
●
Flexible burst search for the analysis of complex signal combinations, short bursts
or signal mix
This user manual contains a description of the functionality that the application provides, including remote control operation.
General R&S FSV/A functions
The application-independent functions for general tasks on the R&S FSV/A are also
available for VSA measurements and are described in the R&S FSV/A user manual. In
particular, this comprises the following functionality:
●
Data management
●
General software preferences and information
The latest version is available for download at the product homepage
http://www.rohde-schwarz.com/product/FSV3000.html.
Additional information
Several application notes discussing vector signal analysis using the R&S FSV3 VSA
application are available from the Rohde & Schwarz website:
1EF93: Modulation Accuracy Measurements of DVB-S2 and DVB-S2X Signals
1EF55: EVM Measurements for ZigBee signals in the 2.4 GHz band
1MA171: How to use Rohde & Schwarz Instruments in MATLAB
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2.1 Introduction to vector signal analysis
Welcome to the R&S FSV3 VSA application
Introduction to vector signal analysis
Installation
You can find detailed installation instructions in the R&S FSV/A Getting Started manual
or in the Release Notes.
● Introduction to vector signal analysis...................................................................... 17
● Starting the VSA application................................................................................... 18
● Understanding the display information....................................................................18
The goal of vector signal analysis is to determine the quality of the signal that is transmitted by the device under test (DUT) by comparing it against an ideal signal. The DUT
is usually connected with the analyzer via a cable. The key task of the analyzer is to
determine the ideal signal. Hence, the analyzer aims to reconstruct the ideal signal
from the measured signal that is transmitted by the DUT. This ideal signal is commonly
referred to as the reference signal, while the signal from the DUT is called the mea-
surement signal.
After extracting the reference signal, the R&S FSV3 VSA application compares the
measurement signal and the reference signal, and the results of this comparison are
displayed.
Example:
The most common vector signal analysis measurement is the EVM ("Error Vector Magnitude") measurement. Here, the complex baseband reference signal is subtracted
from the complex baseband measurement signal. The magnitude of this error vector
represents the EVM value. The EVM has the advantage that it "summarizes" all potential errors and distortions in one single value. If the EVM value is low, the signal quality
of the DUT is high.
Figure 2-1: Simplified schema of vector signal analysis
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2.2 Starting the VSA application
Welcome to the R&S FSV3 VSA application
Understanding the display information
The VSA application adds a new application to the R&S FSV/A.
To activate the VSA application
1. Select the [MODE] key.
A dialog box opens that contains all operating modes and applications currently
available on your R&S FSV/A.
2. Select the "VSA" item.
The R&S FSV/A opens a new measurement channel for the VSA application.
The measurement is started immediately with the default settings. It can be configured
in the VSA "Overview" dialog box, which is displayed when you select the "Overview"
softkey from any menu (see Chapter 5.1, "Configuration overview", on page 164).
Multiple Measurement Channels and Sequencer Function
When you activate an application, a new measurement channel is created which determines the measurement settings for that application. The same application can be activated with different measurement settings by creating several channels for the same
application.
The number of channels that can be configured at the same time depends on the available memory on the instrument.
Only one measurement can be performed at any time, namely the one in the currently
active channel. However, to perform the configured measurements consecutively, a
Sequencer function is provided.
If activated, the measurements configured in the currently active channels are performed one after the other in the order of the tabs. The currently active measurement is
indicated by a
are updated in the tabs (as well as the "MultiView") as the measurements are performed. Sequential operation itself is independent of the currently displayed tab.
For details on the Sequencer function, see the R&S FSV/A User Manual.
symbol in the tab label. The result displays of the individual channels
2.3 Understanding the display information
The following figure shows a measurement diagram during analyzer operation. All different information areas are labeled. They are explained in more detail in the following
sections.
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Welcome to the R&S FSV3 VSA application
Understanding the display information
1
2
3
4
5
1 = Channel bar for firmware and measurement settings
2 = Window title bar with diagram-specific (trace) information
3 = Diagram area
4 = Diagram footer with diagram-specific information, depending on measurement application
5 = Instrument status bar with error messages, progress bar and date/time display
Channel bar information
In VSA application, the R&S FSV/A shows the following settings:
Table 2-1: Information displayed in the channel bar in VSA application
Ref Level Reference level
Offset Reference level offset (if not 0)
Cap Len Capture Length (instead of result length for "Capture Buffer" display), see
"Capture Length Settings" on page 208
Std/Mod Selected measurement standard or, if no standard selected, modulation
type or loaded user-defined modulation file
Res Len Result Length
Att Mechanical and electronic RF attenuation
Freq Center frequency for the RF signal
SR Symbol Rate
Tx filter Transmit filter, see "Transmit Filter Type" on page 173
Res Rng # Number of the selected result range for burst signals, see Chapter 4.6.1,
"Result range", on page 147
Count Statistics count for averaging and other statistical operations, see "Statis-
tic Count" on page 215; cannot be edited directly
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Welcome to the R&S FSV3 VSA application
Understanding the display information
Input Input type of the signal source
See Chapter 5.4.1, "Input settings", on page 188
Burst Burst search active (see "Enabling Burst Searches" on page 217)
Pattern Pattern search active (see "Enabling Pattern Searches" on page 219)
Equalizer "Equalizer" active (see "State" on page 231 )
SGL The sweep is set to single sweep mode.
In addition, the channel bar also displays information on instrument settings that affect
the measurement results even though this is not immediately apparent from the display
of the measured values (e.g. transducer or trigger settings). This information is displayed only when applicable for the current measurement.
For details see the R&S FSV/A Getting Started manual.
Window title bar information
For each diagram, the header provides the following information:
5
1 2
Figure 2-2: Window title bar information in VSA application
1 = Window name
2 = Result type
3 = Data source type
4 = Trace color
5 = Trace number
6 = Displayed signal for Meas&Ref or multi data source: "M" (Meas), "R" (Ref), "C" (Capture buffer), "E"
(Error)
7 = Trace mode
3
4
6 7
Diagram area
The diagram area displays the results according to the selected result displays (see
Chapter 3, "Measurements and result displays", on page 21).
Diagram footer information
The diagram footer (beneath the diagram) contains the start and stop symbols or time
of the evaluation range.
Status bar information
Global instrument settings, the instrument status and any irregularities are indicated in
the status bar beneath the diagram. Furthermore, the progress of the current operation
is displayed in the status bar.
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3 Measurements and result displays
3.1 Evaluation data sources in VSA
Measurements and result displays
Evaluation data sources in VSA
Various different result displays for VSA measurements are available. Which result
types are available depends on the selected data source. You can define which part of
the measured signal is to be evaluated and displayed.
The determined result and evaluation ranges are included in the result displays (where
useful) to visualize the basis of the displayed values and traces.
For background information on the result and evaluation ranges, see Chapter 4.6,
"Measurement ranges", on page 146.)
● Evaluation data sources in VSA..............................................................................21
● Result types in VSA................................................................................................ 25
● Predefined display configuration.............................................................................67
● Common parameters in VSA.................................................................................. 68
All data sources for evaluation available for VSA are displayed in the evaluation bar in
SmartGrid mode.
The data source determines which result types are available (see Table 3-1). For
details on selecting the data source for evaluation, see Chapter 6.5, "Display and win-
dow configuration", on page 257.
In diagrams in the frequency domain (Spectrum transformation, see "Result Type
Transformation" on page 259) the usable I/Q bandwidth is indicated by vertical blue
lines.
Capture Buffer...............................................................................................................22
Measurement & Reference Signal................................................................................ 22
Symbols........................................................................................................................ 23
Error Vector...................................................................................................................23
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Measurements and result displays
Evaluation data sources in VSA
Modulation Errors..........................................................................................................23
Modulation Accuracy.....................................................................................................24
Equalizer....................................................................................................................... 24
Multi Source.................................................................................................................. 24
Capture Buffer
Displays the captured I/Q data.
In "Capture Buffer" result diagrams, the result ranges are indicated by green bars along
the time axis. The currently displayed result range is indicated by a blue bar.
Figure 3-1: Result ranges for a burst signal
Note: You can use the "Capture Buffer" display to navigate through the available result
ranges (using Select Result Rng function), and analyze the individual result ranges in
separate windows.
Once the sweep has stopped, you can change the position of the result range quickly
and easily. Drag the blue bar representing the result range to a different position in the
"Capture Buffer".
The default result type is "Magnitude Absolute".
The following result types are available:
●
Chapter 3.2.21, "Magnitude absolute", on page 48
●
Chapter 3.2.28, "Real/imag (I/Q)", on page 56
●
Chapter 3.2.11, "Frequency absolute", on page 39
●
Chapter 3.2.34, "Vector I/Q", on page 65
Remote command:
LAY:ADD? '1',BEL,TCAP(see LAYout:ADD[:WINDow]? on page 476)
Measurement & Reference Signal
The measurement signal or the ideal reference signal (or both)
The default result type is "Magnitude Relative".
The following result types are available:
●
Chapter 3.2.21, "Magnitude absolute", on page 48
●
Chapter 3.2.23, "Magnitude relative", on page 51
●
Chapter 3.2.26, "Phase wrap", on page 54
●
Chapter 3.2.27, "Phase unwrap", on page 55
●
Chapter 3.2.11, "Frequency absolute", on page 39
●
Chapter 3.2.12, "Frequency relative", on page 40
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Measurements and result displays
Evaluation data sources in VSA
●
Chapter 3.2.28, "Real/imag (I/Q)", on page 56
●
Chapter 3.2.10, "Eye diagram real (I)", on page 38
●
Chapter 3.2.9, "Eye diagram imag (Q)", on page 36
●
Chapter 3.2.8, "Eye diagram frequency", on page 35
●
Chapter 3.2.5, "Constellation I/Q", on page 31
●
Chapter 3.2.34, "Vector I/Q", on page 65
●
Chapter 3.2.4, "Constellation frequency", on page 31
●
Chapter 3.2.33, "Vector frequency", on page 65
Remote command:
LAY:ADD? '1',BEL,REF(see LAYout:ADD[:WINDow]? on page 476)
Symbols
The detected symbols (i.e. the detected bits) displayed in a table.
The default result type is a hexadecimal symbol table.
Other formats for the symbol table are available, but no other result types (see Chap-
ter 3.2.32, "Symbol table", on page 63).
Remote command:
LAY:ADD? '1',BEL, SYMB(see LAYout:ADD[:WINDow]? on page 476)
Error Vector
The modulated difference between the complex measurement signal and the complex
reference signal:
Modulation (measurement signal - reference signal)
For example: EVM = Mag(meas - ref)
The default result type is "EVM".
The following result types are available:
●
Chapter 3.2.7, "Error vector magnitude (EVM)", on page 34
●
Chapter 3.2.28, "Real/imag (I/Q)", on page 56
●
Chapter 3.2.34, "Vector I/Q", on page 65
Remote command:
LAY:ADD? '1',BEL,EVEC(see LAYout:ADD[:WINDow]? on page 476)
Modulation Errors
The difference between the modulated complex samples in the measurement and the
modulated reference signal:
Modulation (measurement signal) - Modulation (reference signal)
For example: Magnitude Error = Mag(meas) - Mag(ref)
The default result type is "Magnitude Error".
The following result types are available:
●
Chapter 3.2.21, "Magnitude absolute", on page 48
●
Chapter 3.2.25, "Phase error", on page 53
●
Chapter 3.2.13, "Frequency error absolute", on page 41
●
Chapter 3.2.14, "Frequency error relative", on page 43
Remote command:
LAY:ADD? '1',BEL,MERR(see LAYout:ADD[:WINDow]? on page 476)
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Measurements and result displays
Evaluation data sources in VSA
Modulation Accuracy
Parameters that characterize the accuracy of modulation.
The default result type is "Result Summary".
The following result types are available:
●
Chapter 3.2.29, "Result summary", on page 57
●
Chapter 3.2.1, "Bit error rate (BER)", on page 27
The results of a "modulation accuracy" measurement can be checked for violation of
defined limits automatically. If limit check is activated and the measured values exceed
the limits, those values are indicated in red in the "Result Summary" table. If limit check
is activated and no values exceed the limits, the checked values are indicated in green.
Remote command:
LAY:ADD? '1',BEL,MACC(see LAYout:ADD[:WINDow]? on page 476)
Equalizer
Filter characteristics of the "equalizer" used to compensate for channel distortion and
parameters of the distortion itself.
The following result types are available:
●
Chapter 3.2.18, "Impulse response magnitude", on page 46
●
Chapter 3.2.19, "Impulse response phase", on page 47
●
Chapter 3.2.20, "Impulse response real/imag", on page 48
●
Chapter 3.2.16, "Frequency response magnitude", on page 45
●
Chapter 3.2.17, "Frequency response phase", on page 45
●
Chapter 3.2.15, "Frequency response group delay", on page 44
●
Chapter 3.2.3, "Channel frequency response magnitude", on page 30
●
Chapter 3.2.2, "Channel frequency response group delay", on page 29
The default result type is "Frequency Response Magnitude".
Remote command:
LAY:ADD? '1',BEL,EQU(see LAYout:ADD[:WINDow]? on page 476)
Multi Source
Combines two data sources in one diagram, with (initially) one trace for each data
source. This display allows you to compare the errors to the captured or measured
data directly in the diagram.
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3.2 Result types in VSA
Measurements and result displays
Result types in VSA
Furthermore, for carrier-in-carrier measurements, this data source makes both carriers
visible.
The default result type is "Spec (Meas+Error)".
The following result types are available:
●
Chapter 3.2.30, "Spectrum (capture buffer + error)", on page 60
●
Chapter 3.2.31, "Spectrum (measurement + error)", on page 62
Remote command:
LAY:ADD? '1',RIGH,MCOM, see LAYout:ADD[:WINDow]? on page 476
The available result types for a window depend on the selected evaluation data source.
The SCPI parameters in the following table refer to the CALC:FORM command, see
CALCulate<n>:FORMat on page 485.
Table 3-1: Available result types depending on data source
Evaluation data
source
"Capture Buffer" "Magnitude Absolute"
"Capture Buffer" "Magnitude Overview Absolute"
"Meas & Ref Signal" "Magnitude Absolute"
Result type SCPI parameter
(selected capture buffer section)
"Real/Imag (I/Q)"
"Frequency Absolute"
"Vector I/Q"
(entire capture buffer)
"Magnitude Relative"
"Phase Wrap"
"Phase Unwrap"
"Frequency Absolute"
"Frequency Relative"
"Real/Imag (I/Q)"
MAGNitude
RIMag
FREQuency
COMP
MOVerview
MAGNitude
MAGNitude
PHASe
UPHase
FREQuency
FREQuency
RIMag
"Eye Diagram Real (I)"
"Eye Diagram Imag (Q)"
"Eye Diagram Frequency"
"Constellation I/Q"
"Constellation I/Q (Rotated)"
IEYE
QEYE
FEYE
CONS
RCON
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Measurements and result displays
Result types in VSA
Evaluation data
source
"Symbols" "Binary" -
"Error Vector" "EVM"
"Modulation Errors" "Magnitude Error"
"Modulation Accuracy"
Result type SCPI parameter
"Vector I/Q"
"Constellation Frequency"
"Vector Frequency"
"Octal" -
"Decimal" -
"Hexadecimal" -
"Real/Imag (I/Q)"
"Vector I/Q"
"Phase Error"
"Frequency Error Absolute"
"Frequency Error Relative"
"Bit Error Rate"
"Result Summary"
COMP
CONF
COVF
MAGNitude
RIMag
COMP
MAGNitude
PHASe
FREQuency
FREQuency
BERate
RSUM
"Equalizer" "Impulse Response Magnitude"
"Impulse Response Phase"
"Impulse Response Real/Imag"
"Frequency Response Magnitude"
"Frequency Response Phase"
"Frequency Response Group Delay"
"Channel Frequency Response Magnitude"
"Channel Frequency Response
Group Delay"
"Multi Source" "Spectrum (Real/Imag) (Capture buf-
fer + Error)"
"Spectrum (Real/Imag) (Measurement
+ Error)"
MAGNitude
UPHase
RIMag
MAGNitude
UPHase
GDELay
MAGNitude
GDELay
RIMag (query only)
RIMag (query only)
For details on selecting the data source and result types for evaluation, see Chap-
ter 6.5, "Display and window configuration", on page 257.
Remote command:
CALCulate<n>:FORMat on page 485
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Measurements and result displays
Result types in VSA
● Bit error rate (BER)................................................................................................. 27
● Channel frequency response group delay.............................................................. 29
● Channel frequency response magnitude................................................................ 30
● Constellation frequency...........................................................................................31
● Constellation I/Q......................................................................................................31
● Constellation I/Q (rotated).......................................................................................33
● Error vector magnitude (EVM)................................................................................ 34
● Eye diagram frequency........................................................................................... 35
● Eye diagram imag (Q).............................................................................................36
● Eye diagram real (I).................................................................................................38
● Frequency absolute.................................................................................................39
● Frequency relative...................................................................................................40
● Frequency error absolute........................................................................................41
● Frequency error relative..........................................................................................43
● Frequency response group delay............................................................................44
● Frequency response magnitude..............................................................................45
● Frequency response phase.....................................................................................45
● Impulse response magnitude..................................................................................46
● Impulse response phase.........................................................................................47
● Impulse response real/imag....................................................................................48
● Magnitude absolute.................................................................................................48
● Magnitude overview (capture buffer).......................................................................50
● Magnitude relative...................................................................................................51
● Magnitude error.......................................................................................................52
● Phase error............................................................................................................. 53
● Phase wrap............................................................................................................. 54
● Phase unwrap......................................................................................................... 55
● Real/imag (I/Q)........................................................................................................56
● Result summary...................................................................................................... 57
● Spectrum (capture buffer + error)........................................................................... 60
● Spectrum (measurement + error)............................................................................62
● Symbol table........................................................................................................... 63
● Vector frequency.....................................................................................................65
● Vector I/Q................................................................................................................65
3.2.1 Bit error rate (BER)
A bit error rate (BER) measurement compares the transmitted bits with the determined
symbol decision bits:
BER = error bits / number of analyzed bits
As a prerequisite for this measurement, the VSA application must know which bit
sequences are correct, i.e. which bit sequences can occur. This knowledge must be
provided as a list of possible data sequences in xml format, which is loaded in the VSA
application (see Chapter 4.9, "Known data files - dependencies and restrictions",
on page 154).
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Measurements and result displays
Result types in VSA
Auxiliary tool to create known data files
An auxiliary tool to create known data files from data that is already available in the
R&S FSV3 VSA application is provided with the instrument free of charge.
See Chapter 7.2.4.2, "How to create known data files", on page 273.
Alternatively, for data generated by a pseudo-random bit sequence (PRBS) generator,
you can specify the algorithm used to generate the data, so the R&S FSV3 VSA application knows which sequences can occur. This function requires the R&S FSV/A-K70P
option. See Chapter 4.10, "Known data from PRBS generators", on page 155.
If known data is specified in the application, the BER result display is available for the
following source types:
●
"Modulation Accuracy"
Note that this measurement can take some time, as each symbol decision must be
compared to the possible data sequences one by one.
The BER measurement is an indicator for the quality of the demodulated signal. High
BER values indicate problems such as:
●
Inadequate demodulation settings
●
Poor quality in the source data
●
False or missing sequences in the known data file
●
Result range alignment leads to a mismatch of the input data with the defined
sequences
A BER value of 0.5 means that for at least one measurement no matching sequence
was found.
See also Chapter 4.4.3, "Demodulation and symbol decisions", on page 121 and the
application sheet R&S®FSW-K70 Measuring the BER and the EVM for Signals with
Low SNR on the Rohde & Schwarz Internet site.
The following information is provided in the "Bit Error Rate" result display:
●
"Bit Error Rate": error bits / number of analyzed bits
●
"Total # of Errors": number of detected bit errors (known data compared to symbol
decisions)
●
"Total # of Bits": number of analyzed bits
For each of these results, the following values are provided:
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Measurements and result displays
Result types in VSA
BER result Description
Current Value for current result range
Minimum Minimum "Current" value during the current measurement
Maximum Maximum "Current" value during the current measurement
Accumulative Total value over several measurements;
For BER: "Total # of Errors" / "Total # of Bits" (similar to average function)
Remote commands:
LAY:ADD? '1',BEL,MACC
To define the required source type (see LAYout:ADD[:WINDow]? on page 476).
CALC:FORM BER
To define the result type (see CALCulate<n>:FORMat on page 485).
CALC:BER?
To query the results (see CALCulate<n>:BERate? on page 504).
3.2.2 Channel frequency response group delay
The frequency response group delay of the channel is the derivation of phase over frequency for the original input signal. It is a measure of phase distortion.
Remote commands:
LAY:ADD? '1',BEL,EQU
To define the required source type (see LAYout:ADD[:WINDow]? on page 476).
CALC:FEED 'XFR:DDEM:IRAT'
To define the channel frequency response result type (see CALCulate<n>:FEED
on page 484).
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3.2.3 Channel frequency response magnitude
Measurements and result displays
Result types in VSA
CALC:FORM GDEL
To define the group delay result type (see CALCulate<n>:FORMat on page 485).
TRAC:DATA? TRACE1
To query the trace results (see TRACe<n>[:DATA]? TRACE<n> and Chap-
ter 10.9.2.6, "Equalizer", on page 498).
The frequency response magnitude of the channel indicates which distortions occurred
during transmission of the input signal. It is only determined if the equalizer is activated.
The bandwidth for which the channel transfer function can be estimated is not only limited by the usable I/Q bandwidth, but also by the bandwidth of the analyzed input signal. Areas with low reception power, e.g. at the filter edges, can suffer from less accurate estimation results.
Remote commands:
LAY:ADD? '1',BEL,EQU
To define the required source type (see LAYout:ADD[:WINDow]? on page 476).
CALC:FEED 'XFR:DDEM:IRAT'
To define the channel frequency response result type (see CALCulate<n>:FEED
on page 484).
CALC:FORM MAGN
To define the magnitude result type (see CALCulate<n>:FORMat on page 485).
TRAC:DATA? TRACE1
To query the trace results (see TRACe<n>[:DATA]? TRACE<n> and Chap-
ter 10.9.2.6, "Equalizer", on page 498).
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3.2.4 Constellation frequency
Measurements and result displays
Result types in VSA
Depending on the modulation type,, the source signal (without inter-symbol interference) as an X/Y plot; only the symbol decision instants are drawn and not connected.
Available for source types:
●
"Meas & Ref Signal"
Figure 3-2: Constellation Frequency result display
A special density trace mode is available for this diagram. The occurrence of each
value within the current result range or evaluation range is indicated by color.
Remote commands:
LAY:ADD? '1',BEL,MEAS
To define the required source type (see LAYout:ADD[:WINDow]? on page 476)
CALC:FORM CONF
To define the result type (see CALCulate<n>:FORMat on page 485)
TRAC:DATA? TRACE1
To query the trace results (see TRACe<n>[:DATA]? TRACE<n> and Chap-
ter 10.9.2.3, "Polar diagrams", on page 497)
3.2.5 Constellation I/Q
The complex source signal (without inter-symbol interference) as an X/Y plot; only the
(de-rotated) symbol decision instants are drawn and not connected
Available for source types:
●
"Meas & Ref Signal"
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Measurements and result displays
Result types in VSA
Figure 3-3: Constellation I/Q diagram for QPSK modulated signal
Markers in the Constellation diagram
Using markers you can detect individual constellation points for a specific symbol.
When you activate a marker in the Constellation diagram, its position is defined by the
symbol the point belongs to. However, the marker result indicates the I and Q values of
the point.
Constellation for subframe or symbol types in multi-modulation signals
For signals with a user-defined frame structure (see Chapter 4.11, "Multi-modulation
analysis (R&S FSV/A-K70M)", on page 157), the constellation diagram displays all
symbols in the entire frame by default. However, if you restrict the evaluation range to
the symbols of a particular subframe, only those constellation points are displayed (see
Chapter 5.10, "Evaluation range configuration", on page 237).
You can also define different colored traces for different symbol types (see Chap-
ter 6.1, "Trace settings", on page 242).
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Measurements and result displays
Result types in VSA
Density trace
A special density trace mode is available for this diagram. The occurrence of each
value within the current result range or evaluation range is indicated by color.
Figure 3-4: Example for a density constellation trace
Remote commands:
LAY:ADD? '1',BEL,MEAS
To define the required source type (see LAYout:ADD[:WINDow]? on page 476).
CALC:FORM CONS
To define the result type (see CALCulate<n>:FORMat on page 485).
TRAC:DATA? TRACE1
To query the trace results (see TRACe<n>[:DATA]? TRACE<n> and Chap-
ter 10.9.2.3, "Polar diagrams", on page 497).
CALCulate<n>:MARKer<m>:Y? on page 455
To query the marker I/Q values.
3.2.6 Constellation I/Q (rotated)
The complex source signal as an X/Y plot. As opposed to the common "Constellation
I/Q" display, the symbol decision instants, including the rotated ones, are drawn and
not connected.
Available for source types:
●
"Meas & Ref Signal"
This result type is only available for signals with a rotating modulation.
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C
tEV
tEVM
k
TkREF
K
C
2
1
periods symbol ofduration T
Measurements and result displays
Result types in VSA
Figure 3-5: Constellation I/Q (Rotated) result display vs. common Constellation I/Q for 3π/8-8PSK
A special density trace mode is available for this diagram. The occurrence of each
value within the current result range or evaluation range is indicated by color.
Remote commands:
LAY:ADD? '1',BEL,MEAS
To define the required source type (see LAYout:ADD[:WINDow]? on page 476).
CALC:FORM RCON
To define the result type (see CALCulate<n>:FORMat on page 485).
TRAC:DATA? TRACE1
To query the trace results (see TRACe<n>[:DATA]? TRACE<n> and Chap-
ter 10.9.2.3, "Polar diagrams", on page 497).
modulation
3.2.7 Error vector magnitude (EVM)
Displays the error vector magnitude as a function of symbols or time.
with t=n·TD and TD=the duration of one sampling period at the sample rate defined by
the display points per symbol parameter (see "Display Points/Sym" on page 259).
The normalization constant C is chosen according to the EVM normalization. By
default C² is the mean power of the reference signal.
and
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Measurements and result displays
Result types in VSA
Note that k=0.5·n·T for Offset QPSK with inactive Offset EVM.
Figure 3-6: Error Vector Magnitude result display
For signals with a user-defined frame structure (see Chapter 4.11, "Multi-modulation
analysis (R&S FSV/A-K70M)", on page 157), the individual subframes are indicated by
vertical green lines.
Available for source types:
●
"Error Vector"
Remote commands:
LAY:ADD? '1',BEL,EVEC
To define the required source type (see LAYout:ADD[:WINDow]? on page 476).
CALC:FORM MAGN
To define the result type (see CALCulate<n>:FORMat on page 485).
TRAC:DATA? TRACE1
To query the trace results (see TRACe<n>[:DATA]? TRACE<n> and Chap-
ter 10.9.2.2, "Cartesian diagrams", on page 496).
3.2.8 Eye diagram frequency
The eye diagram of the currently measured frequencies and/or the reference signal.
The time span of the data depends on the evaluation range (capture buffer).
Available for source types:
●
"Meas & Ref Signal"
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Measurements and result displays
Result types in VSA
Display lines are available in eye diagrams which allow you to determine the size of the
eye, see also Chapter 7.3.2, "How to measure the size of an eye", on page 280.
A special density trace mode is available for this diagram. The occurrence of each
value within the current result range or evaluation range is indicated by color.
Figure 3-7: Eye Diagram Frequency result display with density trace
Remote commands:
LAY:ADD? '1',BEL,MEAS
To define the required source type (see LAYout:ADD[:WINDow]? on page 476).
CALC:FORM FEYE
To define the result type (see CALCulate<n>:FORMat on page 485).
TRAC:DATA? TRACE1
To query the trace results (see TRACe<n>[:DATA]? TRACE<n> and Chap-
ter 10.9.2.2, "Cartesian diagrams", on page 496).
Chapter 10.7.3, "Configuring display lines for eye diagrams", on page 464
3.2.9 Eye diagram imag (Q)
The eye pattern of the quadrature (Q) channel; the x-axis range is from -1 to +1 symbols (MSK: -2 to +2)
Available for source types:
●
"Meas & Ref Signal"
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Measurements and result displays
Result types in VSA
Figure 3-8: Eye Diagram Imag (Q) result display
Display lines are available in eye diagrams which allow you to determine the size of the
eye, see also Chapter 7.3.2, "How to measure the size of an eye", on page 280.
A special density trace mode is available for this diagram. The occurrence of each
value within the current result range or evaluation range is indicated by color.
Figure 3-9: Eye Diagram Imag (Q) result display with density trace
Remote commands:
LAY:ADD? '1',BEL,MEAS
To define the required source type (see LAYout:ADD[:WINDow]? on page 476).
CALC:FORM QEYE
To define the result type (see CALCulate<n>:FORMat on page 485).
TRAC:DATA? TRACE1
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3.2.10 Eye diagram real (I)
Measurements and result displays
Result types in VSA
To query the trace results (see TRACe<n>[:DATA]? TRACE<n> and Chap-
ter 10.9.2.2, "Cartesian diagrams", on page 496).
Chapter 10.7.3, "Configuring display lines for eye diagrams", on page 464
The eye pattern of the inphase (I) channel; the x-axis value range is from -1 to +1 symbols (MSK: -2 to +2)
Available for source types:
●
"Meas & Ref Signal"
Figure 3-10: Eye Diagram Real (I) result display
Display lines are available in eye diagrams which allow you to determine the size of the
eye, see also Chapter 7.3.2, "How to measure the size of an eye", on page 280.
A special density trace mode is available for this diagram. The occurrence of each
value within the current result range or evaluation range is indicated by color.
Remote commands:
LAY:ADD? '1',BEL,MEAS
To define the required source type (see LAYout:ADD[:WINDow]? on page 476).
CALC:FORM IEYE
To define the result type (see CALCulate<n>:FORMat on page 485).
TRAC:DATA? TRACE1
To query the trace results (see TRACe<n>[:DATA]? TRACE<n> and Chap-
ter 10.9.2.2, "Cartesian diagrams", on page 496).
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tMEAS
dt
d
tFREQ
MEAS
2
1
tCapt
dt
d
tFREQ
CAPT
2
1
.
3.2.11 Frequency absolute
Measurements and result displays
Result types in VSA
Chapter 10.7.3, "Configuring display lines for eye diagrams", on page 464
The instantaneous frequency of the signal source; the absolute value is displayed in
Hz.
Available for source types:
●
"Meas & Ref Signal"
●
"Capture Buffer"
Figure 3-11: Frequency Absolute result display
Meas&Ref signal:
with t=n·TD and TD=the duration of one sampling period at the sample rate defined by
the display points per symbol parameter (see "Display Points/Sym" on page 259).
For signals with a user-defined frame structure (see Chapter 4.11, "Multi-modulation
analysis (R&S FSV/A-K70M)", on page 157), and based on the "Meas and Ref" signal,
the individual subframes are indicated by vertical green lines.
Capture buffer:
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tMEAS
dt
d
tFREQ
MEAS
2
1
Measurements and result displays
Result types in VSA
When evaluating the capture buffer, the absolute frequency is derived from the measured phase, with TD=the duration of one sampling period at the sample rate (see
"Sample Rate" on page 208).
Note that this result display is based on an individual capture buffer range. If more than
256 000 samples are captured, overlapping ranges with a size of 256 000 each are
created. Only one range at a time can be displayed in the "Frequency Absolute" result
display. For details see Chapter 4.8, "Capture buffer display", on page 152.
This measurement is mainly of interest when using the MSK or FSK modulation, but
can also be used for the PSK/QAM modulations. However, since these modulations
can have transitions through zero in the I/Q plane, in this case, possibly you notice
uncritical spikes. The reason is that the phase of zero (or a complex value close to
zero) is of limited significance, but still influences the result of the instantaneous frequency measurement.
Remote commands:
LAY:ADD? '1',BEL,MEAS
To define the required source type (see LAYout:ADD[:WINDow]? on page 476).
CALC:FORM FREQ
To define the result type (see CALCulate<n>:FORMat on page 485).
TRAC:DATA? TRACE1
To query the trace results (see TRACe<n>[:DATA]? TRACE<n> and Chap-
ter 10.9.2.1, "Capture buffer results", on page 496/Chapter 10.9.2.2, "Cartesian diagrams", on page 496).
3.2.12 Frequency relative
The instantaneous frequency of the signal source.
The results are normalized to the symbol rate (PSK and QAM modulated signals), the
estimated FSK deviation (FSK modulated signals) or one quarter of the symbol rate
(MSK modulated signals).
with t=n·TD and TD=the duration of one sampling period at the sample rate defined by
the display points per symbol parameter (see "Display Points/Sym" on page 259).
This measurement is mainly of interest when using the MSK or FSK modulation, but
can also be used for the PSK/QAM modulations. See also the note for Chapter 3.2.11,
"Frequency absolute", on page 39.
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tFREQtFREQtERRFREQ
REFMEAS
_
Measurements and result displays
Result types in VSA
Available for source types:
●
"Meas & Ref Signal"
Figure 3-12: Frequency Relative result display
For signals with a user-defined frame structure (see Chapter 4.11, "Multi-modulation
analysis (R&S FSV/A-K70M)", on page 157), the individual subframes are indicated by
vertical green lines.
Remote commands:
LAY:ADD? '1',BEL,MEAS
To define the required source type (see LAYout:ADD[:WINDow]? on page 476).
CALC:FORM FREQ
To define the result type (see CALCulate<n>:FORMat on page 485).
DISP:TRAC:Y:MODE REL
To define relative values (see DISPlay[:WINDow<n>][:SUBWindow<w>]:
TRACe<t>:Y[:SCALe]:MODE on page 489).
TRAC:DATA? TRACE1
To query the trace results (see TRACe<n>[:DATA]? TRACE<n> and Chap-
ter 10.9.2.2, "Cartesian diagrams", on page 496).
3.2.13 Frequency error absolute
Displays the error of the instantaneous frequency in Hz of the measurement signal with
respect to the reference signal as a function of symbols over time.
with t=n·TD and TD=the duration of one sampling period at the sample rate defined by
the display points per symbol parameter (see "Display Points/Sym" on page 259).
Note that this measurement does not consider a possible carrier frequency offset. It
has already been compensated for in the measurement signal.
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Measurements and result displays
Result types in VSA
This measurement is mainly of interest when using the MSK or FSK modulation, but
can also be used for the PSK/QAM modulations. However, since these modulations
can have transitions through zero in the I/Q plane, in this case, you possibly notice
uncritical spikes. The reason is that the phase of zero (or a complex value close to
zero) has in fact limited significance, but still influences the result of the current frequency measurement.
Figure 3-13: Frequency Error Absolute result display
Available for source types:
●
"Modulation Errors"
For signals with a user-defined frame structure (see Chapter 4.11, "Multi-modulation
analysis (R&S FSV/A-K70M)", on page 157), the individual subframes are indicated by
vertical green lines.
Remote commands:
LAY:ADD? '1',BEL,MERR
To define the required source type (see LAYout:ADD[:WINDow]? on page 476).
CALC:FORM FREQ
To define the result type (see CALCulate<n>:FORMat on page 485).
TRAC:DATA? TRACE1
To query the trace results (see TRACe<n>[:DATA]? TRACE<n> and Chap-
ter 10.9.2.2, "Cartesian diagrams", on page 496).
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tFREQtFREQtERRFREQ
REFMEAS
_
3.2.14 Frequency error relative
Measurements and result displays
Result types in VSA
Displays the error of the instantaneous frequency of the measurement signal with
respect to the reference signal as a function of symbols over time.
The results are normalized to the symbol rate (PSK and QAM modulated signals), the
estimated FSK deviation (FSK modulated signals) or one quarter of the symbol rate
(MSK modulated signals).
with t=n·TD and TD=the duration of one sampling period at the sample rate defined by
the display points per symbol parameter (see "Display Points/Sym" on page 259).
This measurement is mainly of interest when using the MSK or FSK modulation, but
can also be used for the PSK/QAM modulations. See also the note for Chapter 3.2.13,
"Frequency error absolute", on page 41.
Figure 3-14: Frequency Error Relative result display
Available for source types:
●
"Modulation Errors"
For signals with a user-defined frame structure (see Chapter 4.11, "Multi-modulation
analysis (R&S FSV/A-K70M)", on page 157), the individual subframes are indicated by
vertical green lines.
Remote commands:
LAY:ADD? '1',BEL,MERR
To define the required source type (see LAYout:ADD[:WINDow]? on page 476).
CALC:FORM FREQ
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3.2.15 Frequency response group delay
Measurements and result displays
Result types in VSA
To define the result type (see CALCulate<n>:FORMat on page 485).
DISP:TRAC:Y:MODE REL
To define relative values (see DISPlay[:WINDow<n>][:SUBWindow<w>]:
TRACe<t>:Y[:SCALe]:MODE on page 489).
TRAC:DATA? TRACE1
To query the trace results (see TRACe<n>[:DATA]? TRACE<n> and Chap-
ter 10.9.2.2, "Cartesian diagrams", on page 496).
The Frequency Response Group Delay of the "equalizer" is the derivation of phase
over frequency. It is a measure of phase distortion.
Available for source types:
●
"Equalizer"
Remote commands:
LAY:ADD? '1',BEL,EQU
To define the required source type (see LAYout:ADD[:WINDow]? on page 476)
CALC:FEED 'XFR:DDEM:RAT'
To define the frequency response result type (see CALCulate<n>:FEED
on page 484).
CALC:FORM GDEL
To define the group delay result type (see CALCulate<n>:FORMat on page 485).
TRAC:DATA? TRACE1
To query the trace results (see TRACe<n>[:DATA]? TRACE<n> and Chap-
ter 10.9.2.6, "Equalizer", on page 498).
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3.2.16 Frequency response magnitude
Measurements and result displays
Result types in VSA
Magnitude of the frequency response of the current equalizer. Note that the frequency
response of the equalizer is not a pure inverted function of the channel response, as
both functions are calculated independently. The frequency response is calculated by
determining an optimal EVM for the input signal.
Available for source types:
●
"Equalizer"
Remote commands:
LAY:ADD? '1',BEL,EQU
To define the required source type (see LAYout:ADD[:WINDow]? on page 476).
CALC:FEED 'XFR:DDEM:RAT'
To define the frequency response result type (see CALCulate<n>:FEED
on page 484).
CALC:FORM MAGN
To define the magnitude result type (see CALCulate<n>:FORMat on page 485).
TRAC:DATA? TRACE1
To query the trace results (see TRACe<n>[:DATA]? TRACE<n> and Chap-
ter 10.9.2.6, "Equalizer", on page 498).
3.2.17 Frequency response phase
Phase of the frequency response of the current "equalizer".
Available for source types:
●
"Equalizer"
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3.2.18 Impulse response magnitude
Measurements and result displays
Result types in VSA
Remote commands:
LAY:ADD? '1',BEL,EQU
To define the required source type (see LAYout:ADD[:WINDow]? on page 476).
CALC:FEED 'XFR:DDEM:RAT'
To define the frequency response result type (see CALCulate<n>:FEED
on page 484).
CALC:FORM UPH
To define the unwrapped phase result type (see CALCulate<n>:FORMat
on page 485).
TRAC:DATA? TRACE1
To query the trace results (see TRACe<n>[:DATA]? TRACE<n> and Chap-
ter 10.9.2.6, "Equalizer", on page 498).
The "Impulse Response Magnitude" shows the magnitude of the equalizer filter in the
time domain.
Available for source types:
●
"Equalizer"
Remote commands:
LAY:ADD? '1',BEL,EQU
To define the required source type (see LAYout:ADD[:WINDow]? on page 476).
CALC:FEED 'XTIM:DDEM:IMP'
To define the "Impulse Response" result type (see CALCulate<n>:FEED
on page 484).
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3.2.19 Impulse response phase
Measurements and result displays
Result types in VSA
CALC:FORM MAGN
To define the "Magnitude" result type (see CALCulate<n>:FORMat on page 485).
TRAC:DATA? TRACE1
To query the trace results (see TRACe<n>[:DATA]? TRACE<n> and Chap-
ter 10.9.2.6, "Equalizer", on page 498).
The "Impulse Response Phase" shows the phase of the equalizer coefficients in the
time domain.
Available for source types:
●
"Equalizer"
Remote commands:
LAY:ADD? '1',BEL,EQU
To define the required source type (see LAYout:ADD[:WINDow]? on page 476).
CALC:FEED 'XTIM:DDEM:IMP'
To define the "Impulse Response" result type (see CALCulate<n>:FEED
on page 484).
CALC:FORM UPH
To define the "Phase" result type (see CALCulate<n>:FORMat on page 485).
TRAC:DATA? TRACE1
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3.2.20 Impulse response real/imag
Measurements and result displays
Result types in VSA
To query the trace results (see TRACe<n>[:DATA]? TRACE<n> and Chap-
ter 10.9.2.6, "Equalizer", on page 498).
The "Real/Imag" diagram of the impulse response is a stem diagram. It displays the filter characteristics in the time domain for both the I and the Q branches individually.
Using this information the equalizer is uniquely characterized and can be recreated by
other applications.
Available for source types:
●
"Equalizer"
Remote commands:
LAY:ADD? '1',BEL,EQU
To define the required source type (see LAYout:ADD[:WINDow]? on page 476).
CALC:FEED 'XTIM:DDEM:IMP'
To define the impulse response result type (see CALCulate<n>:FEED on page 484).
CALC:FORM RIM
To define the real/imag result type (see CALCulate<n>:FORMat on page 485).
TRAC:DATA? TRACE1
To query the trace results (see TRACe<n>[:DATA]? TRACE<n> and Chap-
ter 10.9.2.6, "Equalizer", on page 498).
3.2.21 Magnitude absolute
Source type Capture Buffer:
"Magnitude absolute", that is: the actual signal amplitude, of the captured signal in the
capture buffer.
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tMEAStMag
MEAS
Measurements and result displays
Result types in VSA
Figure 3-15: Magnitude Absolute result display for capture buffer data
For capture buffers containing more than 256,000 samples, the magnitude for a section of the capture buffer (max. 256 000 samples) is displayed. The section is selected
such that it surrounds the currently selected result range. The currently displayed section is indicated in the Magnitude overview (capture buffer) using vertical blue lines.
To display the entire capture buffer with all sections in one diagram, use the Magnitude
overview (capture buffer) result display.
Note that trace modes that calculate results for several sweeps (Average, MinHold,
MaxHold) are not available for the "Magnitude absolute" result display.
For more information on the capture buffer see Chapter 4.8, "Capture buffer display",
on page 152.
Source type Meas & Ref Signal:
The actual signal amplitude is displayed:
with t = n·TD and
TD = the duration of one sampling period at the defined sample rate defined by the display points per symbol parameter (see "Display Points/Sym" on page 259)
For signals with a user-defined frame structure (see Chapter 4.11, "Multi-modulation
analysis (R&S FSV/A-K70M)", on page 157), and based on the "Meas and Ref" signal,
the individual subframes are indicated by vertical green lines.
Remote commands:
LAY:ADD? '1',BEL,CBUF
To define the required source type (see LAYout:ADD[:WINDow]? on page 476).
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tMEAStMag
MEAS
3.2.22 Magnitude overview (capture buffer)
Measurements and result displays
Result types in VSA
CALC:FORM MAGN
To define the result type (see CALCulate<n>:FORMat on page 485).
TRAC:DATA? TRACE1
To query the trace results (see TRACe<n>[:DATA]? TRACE<n> and Chap-
ter 10.9.2.1, "Capture buffer results", on page 496).
To query the start of the result range:
[SENSe:]DDEMod:SEARch:MBURst:STARt[:SYMBols]? on page 502
[SENSe:]DDEMod:SEARch:MBURst:STARt:SAMPles? on page 502
Magnitude of the source signal in the entire capture buffer; the actual signal amplitude
is displayed:
with t=n·TD and
TD=the duration of one sampling period at the sample rate defined by the display points
per symbol parameter (see "Display Points/Sym" on page 259)
Note that for very large numbers of samples (>25 000), the samples are mapped to
25 000 trace points using an autopeak detector for display. Thus, this result display is
not suitable to detect transient effects or analyze individual symbols closely. For these
purposes, use the Magnitude absolute result display instead.
The "Magnitude Overview (Capture Buffer)" is only available for the source type:
●
"Capture Buffer"
Figure 3-16: Magnitude Overview (Capture Buffer) result display
For more information on the capture buffer, see Chapter 4.8, "Capture buffer display",
on page 152.
Restrictions
Note the following restrictions that apply to this result display:
●
Only one trace is available
●
Only the trace modes "Clear/Write" and "View" are available.
See also Chapter 6.1, "Trace settings", on page 242.
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3.2.23 Magnitude relative
Measurements and result displays
Result types in VSA
Remote commands:
LAY:ADD? '1',BEL,CBUF
To define the required source type (see LAYout:ADD[:WINDow]? on page 476).
CALC:FORM MOV
To define the result type (see CALCulate<n>:FORMat on page 485).
TRAC:DATA? TRACE1
To query the trace results (see TRACe<n>[:DATA]? TRACE<n> and Chap-
ter 10.9.2.1, "Capture buffer results", on page 496).
Magnitude of the source signal; the signal amplitude is scaled to the ideal reference
signal
Available for source types:
●
"Meas & Ref Signal"
Figure 3-17: Magnitude Relative result display
For signals with a user-defined frame structure (see Chapter 4.11, "Multi-modulation
analysis (R&S FSV/A-K70M)", on page 157), and based on the "Meas and Ref" signal,
the individual subframes are indicated by vertical green lines.
Remote commands:
LAY:ADD? '1',BEL,MEAS
To define the required source type (see LAYout:ADD[:WINDow]? on page 476).
CALC:FORM MAGN
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tMAGtMAGtERRMAG
REFMEAS
_
3.2.24 Magnitude error
Measurements and result displays
Result types in VSA
To define the result type (see CALCulate<n>:FORMat on page 485).
DISP:TRAC:Y:MODE REL
To define relative values (see DISPlay[:WINDow<n>][:SUBWindow<w>]:
TRACe<t>:Y[:SCALe]:MODE on page 489).
TRAC:DATA? TRACE1
To query the trace results (see TRACe<n>[:DATA]? TRACE<n> and Chap-
ter 10.9.2.2, "Cartesian diagrams", on page 496).
Displays the magnitude error of the measurement signal with respect to the reference
signal (as a function of symbols over time)
with t=n·TD and TD=the duration of one sampling period at the sample rate defined by
the display points per symbol parameter (see "Display Points/Sym" on page 259).
Figure 3-18: Magnitude Error result display
Available for source types:
●
"Modulation Errors"
For signals with a user-defined frame structure (see Chapter 4.11, "Multi-modulation
analysis (R&S FSV/A-K70M)", on page 157), the individual subframes are indicated by
vertical green lines.
Remote commands:
LAY:ADD? '1',BEL,MERR
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tPHASEtPHASEtERRPHASE
REFMEAS
_
3.2.25 Phase error
Measurements and result displays
Result types in VSA
To define the required source type (see LAYout:ADD[:WINDow]? on page 476).
CALC:FORM MAGN
To define the result type (see CALCulate<n>:FORMat on page 485).
TRAC:DATA? TRACE1
To query the trace results (see TRACe<n>[:DATA]? TRACE<n> and Chap-
ter 10.9.2.2, "Cartesian diagrams", on page 496).
Displays the phase error of the measurement signal with respect to the reference signal as a function of symbols over time.
with t=n·TD and TD=the duration of one sampling period at the sample rate defined by
the display points per symbol parameter (see "Display Points/Sym" on page 259).
Figure 3-19: Phase Error result display
Available for source types:
●
"Modulation Errors"
For signals with a user-defined frame structure (see Chapter 4.11, "Multi-modulation
analysis (R&S FSV/A-K70M)", on page 157), the individual subframes are indicated by
vertical green lines.
Remote commands:
LAY:ADD? '1',BEL,MERR
To define the required source type (see LAYout:ADD[:WINDow]? on page 476).
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tMEAStPhase
MEAS
3.2.26 Phase wrap
Measurements and result displays
Result types in VSA
CALC:FORM PHAS
To define the result type (see CALCulate<n>:FORMat on page 485).
TRAC:DATA? TRACE1
To query the trace results (see TRACe<n>[:DATA]? TRACE<n> and Chap-
ter 10.9.2.2, "Cartesian diagrams", on page 496).
The phase or argument of the signal; the display is limited to the phase value range of
[-180°, 180°]
with t=n·TD and TD=the duration of one sampling period at the sample rate defined by
the display points per symbol parameter (see "Display Points/Sym" on page 259).
Available for source types:
●
"Meas & Ref Signal"
Figure 3-20: Phase Wrap result display
For signals with a user-defined frame structure (see Chapter 4.11, "Multi-modulation
analysis (R&S FSV/A-K70M)", on page 157), the individual subframes are indicated by
vertical green lines.
Remote commands:
LAY:ADD? '1',BEL,REF
To define the required source type (see LAYout:ADD[:WINDow]? on page 476).
CALC:FORM PHASe
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3.2.27 Phase unwrap
Measurements and result displays
Result types in VSA
To define the result type (see CALCulate<n>:FORMat on page 485).
TRAC:DATA? TRACE1
To query the trace results (see TRACe<n>[:DATA]? TRACE<n> and Chap-
ter 10.9.2.2, "Cartesian diagrams", on page 496).
The phase of the signal; the display is not limited to [-180°, 180°].
Available for source types:
●
"Meas & Ref Signal"
Figure 3-21: Phase Unwrap result display
For signals with a user-defined frame structure (see Chapter 4.11, "Multi-modulation
analysis (R&S FSV/A-K70M)", on page 157), the individual subframes are indicated by
vertical green lines.
Remote commands:
LAY:ADD? '1',BEL,MEAS
To define the required source type (see LAYout:ADD[:WINDow]? on page 476).
CALC:FORM UPHase
To define the result type (see CALCulate<n>:FORMat on page 485).
TRAC:DATA? TRACE1
To query the trace results (see TRACe<n>[:DATA]? TRACE<n> and Chap-
ter 10.9.2.2, "Cartesian diagrams", on page 496).
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3.2.28 Real/imag (I/Q)
Measurements and result displays
Result types in VSA
Real and imaginary part of the measurement or reference signal in separate measurement diagrams; the x-axis (scaled in time units or symbols) is identical for both diagrams.
Available for source types:
●
"Capture Buffer"
●
"Meas & Ref Signal"
●
"Error Vector"
Figure 3-22: Real/Imag (I/Q) result display
Capture buffer display
Note that this result display is based on an individual capture buffer range. If more than
256 000 samples are captured, overlapping ranges with a size of 256 000 each are
created. Only one range at a time can be displayed in the "Real/Imag" result display.
For details see Chapter 4.8, "Capture buffer display", on page 152.
The scaling of the capture buffer depends on the input source:
●
Scaling is relative to the current reference level for RF input.
●
Scaling is relative to the full scale level for I/Q input.
Remote commands:
LAY:ADD? '1',BEL,MEAS
To define the required source type (see LAYout:ADD[:WINDow]? on page 476).
CALC:FORM RIMag
To define the result type (see CALCulate<n>:FORMat on page 485).
TRAC:DATA? TRACE1
To query the trace results (see TRACe<n>[:DATA]? TRACE<n> and Chap-
ter 10.9.2.2, "Cartesian diagrams", on page 496).
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3.2.29 Result summary
Measurements and result displays
Result types in VSA
The "Modulation Accuracy" results in a table. For details on the parameters see Chap-
ter 3.4, "Common parameters in VSA", on page 68.
"Freezing" the displayed values
You can freeze the contents of the "Result Summary" after a measurement to maintain
the values on the display, while the measurement continues or is restarted. As for
graphical displays, set the Trace Mode for the "Result Summary" to "View". The table is
no longer updated. The "View" trace mode is indicated in the window title. To update
the "Result Summary" as usual, set the trace mode back to "Clear Write".
Basis of evaluation
Most values that are displayed in the "Result Summary" are calculated over the "Evaluation Range" (see Chapter 5.10, "Evaluation range configuration", on page 237). They
are evaluated according to the setting of the Display Points/Sym parameter. For example, if "Display Points/Symbol" is "1", only the symbol instants contribute to the result
displayed in the "Result Summary".
Table 3-2: Results calculated over the evaluation range
PSK, MSK, QAM FSK
"EVM" "Frequency Error"
"MER" "Magnitude Error"
"Phase Error" "Power"
"Magnitude Error"
"Rho"
"Power"
The following results that are based on internal estimation algorithms (see Chapter 4.5,
"Signal model, estimation and modulation errors", on page 129) are calculated over the
"Estimation range" (see also Chapter 4.5.1.2, "Estimation", on page 131).
Table 3-3: Results calculated over the estimation range
PSK, MSK, QAM FSK
"Carrier Frequency Error" "FSK Deviation Error"
"Symbol Rate Error"
"I/Q Skew"
"I/Q Offset" "FSK Measurement Deviation"
"I/Q Imbalance" "Carrier Frequency Error"
"Gain Imbalance" "Carrier Frequency Drift"
"Quadrature Error"
"Amplitude Droop"
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Current value
In the "Current" column, the value evaluation for the current evaluation is displayed.
For example, the "EVM Peak" value in the current sweep corresponds to the peak of
the trace values within the evaluation range for the current sweep (as indicated by
marker 1 in Figure 3-23).
Figure 3-23: Example for Result Summary with current EVM peak value marked
If you want to compare the trace values to the results of the "Result Summary", make
sure to match the displayed points per symbol of the trace and of the "Result Summary". Refer to "Display Points/Sym" on page 259 for details.
Mean value
In the "Mean" column, the linear mean of the values that are in the "Current" column is
displayed. Note that if the values are in a logarithmic representation, e.g. the I/Q Offset, the linear values are averaged.
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Peak value
In the "Peak" column, the maximum value that occurred during several evaluations is
displayed. Note that when the value can be positive and negative, e.g. the phase error,
the maximum absolute value (maintaining its sign) is displayed. The peak value of
"Rho" is handled differently, since its minimum value represents the worst case. In that
case, the minimum value is displayed.
Standard Deviation
The value for the standard deviation is calculated on the linear values and then converted to the displayed unit.
95-percentile
The 95-percentile value is based on the distribution of the current values. Since the
phase error and the magnitude error can usually be assumed to be distributed around
zero, the 95-Percentile for these values is calculated based on their absolute values.
Again, the "Rho" value is handled differently. Here, the 5-Percentile is displayed, since
the lowest rho value represents the worst case.
Remote commands:
LAY:ADD? '1',BEL, MACC
To define the required source type (see LAYout:ADD[:WINDow]? on page 476).
CALC:FORM RSUM
To define the result type (see CALCulate<n>:FORMat on page 485).
TRAC:DATA? TRACE1
To query the trace results (see TRACe<n>[:DATA] on page 494 and Chapter 10.9.2.5,
"Result summary", on page 497).
CALC:MARK:FUNC:DDEM:STAT:<parameter>
To query individual parameter values (see Chapter 10.9.4, "Retrieving parameter val-
ues", on page 503.
Result Summary - Individual Results
The "Result Summary" can display either all or only a single modulation accuracy
parameter. Only the most important parameters can be displayed individually, namely
the parameters for which modulation accuracy limits can be defined (see "Limit Value"
on page 256).
To select individual results for display, tap the "Result Summary" table header (only
once - a double-tap maximizes the "Result Summary" window). A "Table Configuration"
dialog box is displayed in which you can select the parameter to be displayed.
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Measurements and result displays
Result types in VSA
By default, all parameters are displayed. If you select a specific parameter, the "Result
Summary" display is replaced by the individual result display.
Figure 3-24: Result display for individual value in Result Summary
In addition to the current measurement value, the statistical results (see Chap-
ter 3.2.29, "Result summary", on page 57) and the peak limit value (see "Limit Value"
on page 256) for the selected parameter are displayed.
For details on the displayed results, see Chapter 3.4, "Common parameters in VSA",
on page 68.
Remote command:
DISPlay[:WINDow<n>]:ITEM[:LINE][:VALue] on page 487
3.2.30 Spectrum (capture buffer + error)
This display combines two diagrams in one. The first trace displays the spectrum of the
real/imaginary data in the capture buffer. The second trace displays the spectrum of
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Result types in VSA
the real/imaginary data of the error. Optionally, the data source of the traces can be
switched. Which source is currently displayed for which trace is indicated in the window
title bar.
(See also Figure 2-2).
Carrier-in-carrier signals
For carrier-in-carrier measurements, this result display makes both carriers visible. The
following example shows two superimposed QPSK signals: one with a symbol rate of
10 MHz (the analyzed signal, yellow), one with a symbol rate of 3 MHz, whose spectrum becomes visible in the error trace (blue).
Figure 3-25: Example of a carrier-in-carrier signal in a multi source result display.
Similarly, the "Spectrum (Measurement + Error)" result display can be used to reveal
carrier-in-carrier signals.
Remote commands:
LAY:ADD? '1',BEL,MCOM
To define the required source type (see LAYout:ADD[:WINDow]? on page 476).
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3.2.31 Spectrum (measurement + error)
Measurements and result displays
Result types in VSA
CALC:FEED 'XTIM:DDEM:TCAP:ERR'
To define the result type (see CALCulate<n>:FEED on page 484).
CALC:TRAC TCAP; CALC:TRAC2 ERR
To define trace1 to be based on the capture buffer data and trace 2 on the error
(default, see CALCulate<n>:TRACe<t>[:VALue] on page 449).
TRAC:DATA? TRACE1
To query the trace results for capture buffer data (see TRACe<n>[:DATA]?
TRACE<n> and Chapter 10.9.2.4, "Symbols", on page 497).
TRAC:DATA? TRACE2
To query the trace results for error data.
This display combines two diagrams in one. The first trace displays the spectrum of the
real/imaginary data from the measured signal. The second trace displays the spectrum
of the real/imaginary data of the error. Optionally, the data source of the traces can be
switched. Which source is currently displayed for which trace is indicated in the window
title bar.
(See also Figure 2-2).
Remote commands:
LAY:ADD? '1',BEL,MCOM
To define the required source type (see LAYout:ADD[:WINDow]? on page 476).
CALC:FEED 'XTIM:DDEM:MEAS:ERR'
To define the result type (see CALCulate<n>:FEED on page 484).
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3.2.32 Symbol table
Measurements and result displays
Result types in VSA
CALC:TRAC MEAS; CALC:TRAC2 ERR
To define trace1 to be based on the measurement data and trace 2 on the error
(default, see CALCulate<n>:TRACe<t>[:VALue] on page 449).
TRAC:DATA? TRACE1
To query the trace results for measurement data (see TRACe<n>[:DATA]?
TRACE<n> and Chapter 10.9.2.4, "Symbols", on page 497).
TRAC:DATA? TRACE2
To query the trace results for error data.
Symbol numbers are displayed as a table. Each symbol is represented by an entry in
the table. The symbols can be displayed in binary, octal, hexadecimal or decimal format. Selected symbols (using markers) are highlighted by a blue frame.
Example:
Figure 3-26: Symbols result display in hexadecimal mode
The evaluation range is indicated by red brackets.
If a pattern search is active, a found pattern is indicated by a green background in the
symbol table. If, during demodulation, individual symbols do not match the pattern after
all, these symbols are indicated by red values.
If known data is loaded as a reference, symbols which do not match this data are also
indicated by red values.
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Figure 3-27: Symbol errors in the symbol table
Tip: If you assume that a signal has a pattern, but do not know it in advance, you can
identify it using the symbol table. Measure the signal and check for a pattern in the
symbol table. Then you can copy the symbols from the symbol table to the pattern definition for subsequent measurements (see"Import Symbols" on page 225 ).
Signals with two different modulation types
For signals with two different modulation types (requires option R&S FSV/A-K70M), the
color of the symbol field indicates the used Modulation and Type:
●
Green background: Pattern modulation and pattern type (for pattern only)
●
Green frame: Pattern modulation and data type (for meta data)
●
No highlighting: Data modulation and data type (for payload data)
Remote commands:
To define the required source type (see LAYout:ADD[:WINDow]? on page 476):
LAY:ADD? '1',BEL, 'XTIM:DDEM:SYMB'
To define the symbol format:
CALCulate<n>:FORMat on page 485
To query the results (see TRACe<n>[:DATA] on page 494 and Chapter 10.9.2.4,
"Symbols", on page 497):
Symbols:
TRAC1:DATA? or TRAC1:DATA? STR
Symbol errors:
TRAC1:DATA? MSTR
Pattern errors:
TRAC1:DATA? PSTR
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3.2.33 Vector frequency
Measurements and result displays
Result types in VSA
The instantaneous frequency of the source signal as an X/Y plot; all available samples
(as defined by the display points per symbol parameter (see "Display Points/Sym"
on page 259)) are drawn and connected.
Available for source types:
●
"Meas & Ref Signal"
Figure 3-28: Vector Frequency result display
A special density trace mode is available for this diagram. The occurrence of each
value within the current result range or evaluation range is indicated by color.
Remote commands:
LAY:ADD? '1',BEL,MEAS
To define the required source type (see LAYout:ADD[:WINDow]? on page 476)
CALC:FORM COVF
To define the result type (see CALCulate<n>:FORMat on page 485)
TRAC:DATA? TRACE1
To query the trace results (see TRACe<n>[:DATA]? TRACE<n> and Chap-
ter 10.9.2.3, "Polar diagrams", on page 497)
3.2.34 Vector I/Q
The complex source signal as an X/Y plot; all available samples (as defined by the display points per symbol parameter, see "Display Points/Sym" on page 259) are drawn
and connected.
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The scaling of the capture buffer depends on the input source:
●
Scaling is relative to the current reference level for RF input.
●
Scaling is relative to the full scale level for I/Q input.
Available for source types:
●
"Capture Buffer"
●
"Meas & Ref Signal"
●
"Error Vector"
Capture buffer display
Note that this result display is based on an individual capture buffer range. If more than
256 000 samples are captured, overlapping ranges with a size of 256 000 each are
created. Only one range at a time can be displayed in the "Vector I/Q" result display.
For details see Chapter 4.8, "Capture buffer display", on page 152.
Figure 3-29: Vector I/Q result display
A special density trace mode is available for this diagram. The occurrence of each
value within the current result range or evaluation range is indicated by color.
Remote commands:
LAY:ADD? '1',BEL,MEAS
To define the required source type (see LAYout:ADD[:WINDow]? on page 476).
CALC:FORM COMP
To define the result type (see CALCulate<n>:FORMat on page 485).
TRAC:DATA? TRACE1
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3.3 Predefined display configuration
Measurements and result displays
Predefined display configuration
To query the trace results (see TRACe<n>[:DATA]? TRACE<n> and Chap-
ter 10.9.2.3, "Polar diagrams", on page 497).
Access: [MEAS] > "Predefined Display Config"
The R&S FSV3 VSA application allows you to configure the screen layout very flexibly
according to your specific measurement requirements. To get started, some typical and
useful display configurations are predefined. Select the required scenario and the display is configured suitably.
To store your personal typical screen layout, save your current measurement settings
(including the screen layout) as a standard.
See "To store settings as a standard file" on page 263.
Typical
Provides several result displays for the most frequently required results when measuring a known signal using a specific modulation.
Overview
Provides useful result displays to determine the relevant signal characteristics of an
unknown signal.
See also the application sheet R&S®FSW-K70 Analyzing Unknown Signals on the
Rohde & Schwarz Internet site.
Remote command:
[SENSe:]DDEMod:PRESet:CALC on page 483
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3.4 Common parameters in VSA
Measurements and result displays
Common parameters in VSA
Depending on the modulation type you are using, different signal parameters are determined during vector signal analysis and displayed in the Result summary.
Details concerning the calculation of individual parameters can be found in Chap-
ter 4.5, "Signal model, estimation and modulation errors", on page 129 and Chapter F,
"Formulae", on page 559.
Table 3-4: Parameters for PSK, QAM and MSK modulation
Parameter Description SCPI parameter
"EVM - RMS/Peak" "Error Vector" Magnitude, normalized to mean reference
power by default (see "Normalize EVM to" on page 233)
"MER - RMS/Peak" Modulation Error Ratio (MER)
"Phase Error RMS"/"Peak"
"Magnitude Error RMS"/"Peak"
"Carrier Frequency
Error"
"Symbol Rate Error" Difference between the currently measured symbol rate and
"I/Q Skew" Constant time difference between the I and Q data, for
"Rho"
"I/Q Offset" Offset in the original input
The phase difference between the measurement vector and
the reference vector
The average (RMS) and peak magnitude error in %. The
magnitude error is the difference of the measured magnitude
to the magnitude of the reference signal. The magnitude
error is normalized to the mean magnitude of the reference
signal.
The mean carrier frequency offset in Hz
the defined symbol rate in ppm.
(Only if compensation for SRE is activated, see "Compen-
sate for... [ (PSK, MSK, ASK, QAM)]" on page 230)
example due to different cable lengths
(Only if compensation for I/Q skew is activated, see "Com-
pensate for... [ (PSK, MSK, ASK, QAM)]" on page 230)
EVM
SNR
PERR
MERRor
CFERror
SRER
IQSK
RHO
OOFFset
"I/Q Imbalance" Not for BPSK.
"Gain Imbalance" Not for BPSK.
"Quadrature Error" Not for BPSK.
"Amplitude Droop" The decrease of the signal power over time in the transmitter
"Power" The power of the measured signal
IQIMbalance
GIMBalance
QERRor
ADRoop
MPOWer
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Table 3-5: Parameters for FSK modulation only
Parameter Description SCPI parameter
"Frequency Error RMS"/"Peak"
"FSK Deviation Error" The deviation error of FSK modulated signals in Hz, i.e.
"FSK Meas Deviation" The estimated deviation of FSK modulated signals in Hz.
"FSK Ref Deviation" The reference deviation you have set in Hz.
"Carrier Frequency
Drift"
The average (RMS) and peak frequency error in %. The
frequency error is the difference of the measured frequency and the reference frequency. The frequency error
is normalized to the estimated FSK deviation.
the difference of the measured FSK deviation and the
user-defined FSK reference deviation.
The mean carrier frequency drift in Hz per symbol.
FSK:DERRor
FDERror
FSK:MDEViation
FSK:RDEViation
FSK:CFDRift
Remote command:
CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:<Parameter>?
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4 Measurement basics
Measurement basics
Filters and bandwidths during signal processing
Some background knowledge on basic terms and principles used in VSA is provided
here for a better understanding of the required configuration settings.
For information on the basic processing of I/Q data in the R&S FSV/A, see the
R&S FSV/A I/Q Analyzer User Manual.
● Filters and bandwidths during signal processing.................................................... 70
● Sample rate, symbol rate and I/Q bandwidth..........................................................77
● Symbol mapping..................................................................................................... 82
● Overview of the demodulation process................................................................. 116
● Signal model, estimation and modulation errors...................................................129
● Measurement ranges............................................................................................ 146
● Display points vs estimation points per symbol.....................................................151
● Capture buffer display...........................................................................................152
● Known data files - dependencies and restrictions.................................................154
● Known data from PRBS generators......................................................................155
● Multi-modulation analysis (R&S FSV/A-K70M).....................................................157
● I/Q data import and export.................................................................................... 163
4.1 Filters and bandwidths during signal processing
This section describes the used filters in vector signal analysis with an R&S FSV/A,
and the bandwidth after each filter.
The relevant filters for vector signal analysis are shown in Figure 4-1.
Figure 4-1: Block diagram of bandwidth-relevant filters for vector signal analysis
●
After the IF Filter (only for RF input operation): bandwidth = 12.8 MHz or 40 MHz,
depending on the Data acquisition settings and the installed bandwidth options
●
After the digital hardware section:
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Filters and bandwidths during signal processing
The phase and amplitude distortions of the IF filter have been compensated for.
Usually, the I/Q data has a usable bandwidth of about:
0.8 * sample rate
For details, refer to Chapter 4.1.1, "I/Q bandwidth", on page 71.
The I/Q data sample rate and bandwidth are automatically adjusted to the set sym-
bol rate. For most modulated signals, even the smallest allowed value for the sam-
ple rate leads to a sufficient I/Q data bandwidth. The whole spectrum of the input
signal is captured, but most adjacent channels and interferers are effectively sup-
pressed. Only for very wide signals (FSK, no TX-filter used) it can be necessary to
try higher values for the sample rate (see Chapter 4.2, "Sample rate, symbol rate
and I/Q bandwidth", on page 77), increasing the I/Q bandwidth. The I/Q data
delivered to the DSP section has no considerable amplitude or phase distortion
and a suitable bandwidth.
The "Signal Capture" dialog box ("Data Acquisition" tab) shows the sample rate and
the usable I/Q bandwidth achieved for the current settings (see "Usable I/Q Bandwidth"
on page 209).
●
After the optional measurement filter:
Various measurement filters which have different bandwidths can filter the mea-
surement signal and the reference signal.
The filters described above are the ones that directly affect the bandwidth of the captured I/Q data and the final measurement signal and reference signal. Note, however,
that several other filters are also involved in the DSP section but are not mentioned
above:
●
Receive filter to prevent ISI (intersymbol-interference)
●
Filters necessary for various estimators
●
Others
4.1.1 I/Q bandwidth
The bandwidth of the I/Q data used as input for the vector signal analysis is filtered as
described in Chapter 4.1, "Filters and bandwidths during signal processing",
on page 70. Its flat, usable bandwidth (no considerable amplitude or phase distortion)
depends on:
●
The used sample rate, which depends on:
– The defined "Symbol Rate" (see "Symbol Rate" on page 173)
– The defined "Sample Rate" parameter (see "Sample Rate" on page 208
●
The type of input used (digital baseband input, RF input, etc.)
For details on the maximum usable bandwidth, see Chapter 4.2, "Sample rate, symbol
rate and I/Q bandwidth", on page 77.
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4.1.2 Demodulation bandwidth (measurement bandwidth)
Measurement basics
Filters and bandwidths during signal processing
The sample rate and the usable I/Q bandwidth achieved for the current settings is displayed in the "Signal Capture" dialog, see Chapter 5.5.1, "Data acquisition",
on page 207.
Some modulation systems do not use a receive filter. In these cases, take special care
that no interference or adjacent channels occur within the demodulation bandwidth. Set
the "Sample rate" parameter to a low value (see "Sample Rate" on page 208).
Typical communication systems demand special receive or measurement filters (e.g.
root-raised cosine receive filter or EDGE measurement filter).
If no such filtering is performed, make sure that interfering signals or adjacent channels
do not fall within the demodulation bandwidth.
4.1.3 Modulation and demodulation filters
For demodulation, the analyzer requires sample points at which only information of the
current symbol and none of neighboring symbols is present (symbol points). These
points are also called ISI-free points (ISI = intersymbol interference). If the transmitter
does not provide an ISI-free signal after the transmit filter (TX filter), the analyzer can
filter the input signal using a receive filter or Rx filter. If the transmitter uses an RRC
(root-raised cosine) filter, the analyzer must also use an RRC filter to obtain ISI-free
points.
In many PSK systems, RRC filters are used as transmit, receive and measurement filters. To determine the I/Q modulation error, the measurement signal must be compared with the corresponding ideal signal. Therefore, the analyzer calculates a refer-
ence filter by convolving the coefficient of the transmit filter ("Tx filter") and the
"Meas filter" (see Figure 4-2).
When measuring unfiltered signals (e.g. to determine nonlinear signal distortions), no
measurement filter is switched into the signal path and the reference filter is identical
to the transmit filter (see Figure 4-2).
In the baseband block diagrams (see Figure 4-2), the system-theoretical transmitter
and analyzer filters are shown for PSK and QAM demodulation. For the sake of clearness, RF stages, IF filters and the filter stages of the digital hardware section are not
shown.
For a correct demodulation, the following filters have to be accurately specified for the
analyzer:
●
Transmit filter: filter characteristic of transmitter
●
Measurement filter:
– PSK, QAM, UserQAM, MSK:
The I and the Q part of the measurement and the reference signal are filtered
with this filter.
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Filters and bandwidths during signal processing
– FSK:
The instantaneous frequency of the measurement reference signal is filtered.
In many applications, the measurement filter is identical to the receive filter.
The receive filter (also referred to as an ISI filter) is configured internally depending on
the transmit filter. The goal is to produce intersymbol-interference-free points for the
demodulation.
The reference filter generates the ideal transmitted signal (after meas filtering). The
analyzer calculates the reference filter from the above filters (convolution operation
transmit filter * meas filter).
Typical combinations of transmit and measurement filters are shown in Table C-3; they
can be set in the R&S FSV3 VSA application using "Meas filter = AUTO" (see " Using
the Transmit Filter as a Measurement Filter (Auto)" on page 236). For some filters, a
roll-off factor is required:
Filter type Required parameters
RC (raised cosine) Alpha
RRC (root-raised
cosine)
Gaussian BT
Alpha
Typically the Alpha/BT value of the measurement filter is the same as the value of the
transmission filter.
4.1.4 Measurement filters
The measurement filter can be used to filter the following two signals in the same way:
●
The measurement signal (after coarse frequency, phase and timing synchroniza-
tion have been achieved)
●
The reference signal, i.e the I/Q symbols that have been determined in the demod-
ulator and have already been filtered with the Transmit filter;
For FSK, the measurement filter filters the instantaneous frequency of the signal, not
the I/Q signal.
For MSK, PSK, QAM and User QAM the measurement filter filters the real part and
imaginary part of these signals (i.e. not the instantaneous frequency or magnitude of
the signal).
The R&S FSV3 VSA application defines the error signal as the difference between the
reference signal and the measurement signal. Thus, the measurement filter also
shapes the spectrum of the error signal, which is used to calculate the EVM, for example.
In many applications, the measurement filter is the same as the RX filter. However,
unlike the measurement filter, the RX filter is not relevant for the measurement, but is
only required to create the reference signal optimally.
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Filters and bandwidths during signal processing
If possible, the RX filter and the transmit filter are chosen such that their combination
results in an Inter-Symbol Interference (ISI) free system (see Figure 4-2 and Fig-
ure 4-3).
Figure 4-2: Measurement filter in the block diagram (MSK, PSK, QAM and UserQAM)
Figure 4-3: Modulator with Transmit filter in detail
As the measurement filters of the R&S FSV3 VSA application have low-pass characteristics, they suppress high frequency distortion components in the Meas/Ref/Error
signal. The errors are weighted spectrally. Thus, turning off the measurement filter can
have an influence on the numeric and graphical error values. However, to measure
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4.1.5 Customized filters
Measurement basics
Filters and bandwidths during signal processing
non-linear distortions, which usually produce high frequency components, switch off
the measurement filter.
Predefined measurement filters
The most frequently required measurement filters are provided by the R&S FSV3 VSA
application (see Chapter C.2, "Measurement filters", on page 553).
The frequency response of the available standard-specific measurement filters is
shown in Chapter F.6.2, "Measurement filter", on page 566.
The analytical filter types RC (raised cosine), RRC (root-raised cosine), GAUSSIAN,
and the most important standard-specific filters, are already integrated in the R&S
FSV3 VSA application. In addition, it is possible to use user-defined measurement and
transmit filters. Customized filters are useful for the following purposes:
●
Developing new networks and modulation methods for which no filters are defined
yet
●
Measuring transmitter characteristics with slightly modified (e.g. shortened) trans-
mitter filters
An external program ("FILTWIZ") is offered to convert user-defined filters. This program
generates filter files (*.vaf) which can be transferred to the analyzer with a USB
device, for example. The program can be downloaded together with a detailed description as a precompiled MATLAB® file (MATLAB pcode) on the Internet, at http://
www.rohde-schwarz.com (search term "FILTWIZ").
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Filters and bandwidths during signal processing
Figure 4-4: FILTWIZ - filter tool for VSA
It is possible to load customized transmit filters and customized measurement filters. If
you select a customized transmit filter, the internal receive filter coefficients are calculated automatically right away.
Unlike the R&S FSV3 VSA application, the R&S FSQ-K70 required you to transfer a
user-defined receive filter, as well.
If you upload a customized transmit filter and leave the measurement filter set to "automatic", the internally calculated receive filter is used as a measurement filter. Note that
this filter is not necessarily suitable for your specific signal. The filter is optimized such
that the intersymbol interference is low. Hence, you probably see a clear eye diagram
and a "Vector I/Q" diagram with a recognizable constellation. However, a filter that has
low intersymbol interference can lead to noise enhancement, which is commonly undesirable for a measurement filter.
To avoid noise enhancement, it is recommended that you do one of the following:
●
Design your own measurement filter and upload it as a user filter.
●
Select a suitable measurement filter from the list.
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4.2 Sample rate, symbol rate and I/Q bandwidth
Measurement basics
Sample rate, symbol rate and I/Q bandwidth
Transferring filter files to the R&S FSV/A
You can transfer the (.vaf) filter files to the R&S FSV/A using a USB memory device.
The "Symbol Rate" defined in the "Signal Description" settings determines how many
symbols are captured and demodulated during a certain measurement time. However,
for each symbol more than one sample can be captured, so that the sample rate can
be higher than the symbol rate.
The "Sample Rate" parameter in the "Signal Capture" settings defines the number of
samples to capture per symbol. (Do not confuse this number with the estimation
points per symbol or display points per symbol, see Chapter 4.7, "Display points vs
estimation points per symbol", on page 151). The resulting sample rate (depending on
the "Symbol Rate") is indicated behind the parameter.
The number of samples to capture per symbol is commonly referred to as the "Cap-
ture Oversampling" value in Rohde & Schwarz signal and spectrum analyzers.
The resulting sample rate, also referred to as the user or output sample rate, is the rate
at which the I/Q data is demodulated and analyzed. The sample rate also affects the
demodulation (measurement) bandwidth. If the bandwidth is too narrow, the signal is
not displayed completely. If the bandwidth is too wide, interference from outside the
actual signal to be measured can distort the result. Thus, for signals with a large frequency spectrum (e.g. FSK modulated signals), a higher sample rate can be necessary.
(For further details, see Chapter 4.1, "Filters and bandwidths during signal processing",
on page 70.)
For an indication of the required sample rate, view the "Real/Imag (I/Q)" display of the
capture buffer with a "Spectrum" transformation. If the complete signal is displayed
within the usable I/Q bandwidth, the selected value is suitable.
Figure 4-5: Determining the I/Q bandwidth: Real/Imag (I/Q) display of the capture buffer with a spec-
trum transformation
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Sample rate, symbol rate and I/Q bandwidth
If the signal is cut off, increase the sample rate.
If the signal is too small, decrease the sample rate by changing one of the following
settings:
●
The "Symbol Rate" defined in the "Signal Description" settings
●
The "Sample Rate" in the "Data Acquisition" settings
As described above, the sample rate defines the number of samples to capture per
symbol. Thus, the maximum sample rate depends on the maximum number of symbols
to be captured (the symbol rate) and vice versa.
The maximum sample rate for the R&S FSV/A is 10 GHz (see below). Thus, the maximum symbol rate is:
Table 4-1: Maximum symbol rate depending on sample rate parameter
Sample rate parameter Max. symbol rate
2* symbol rate 5000 Msymbols
4* symbol rate 2500 Msymbols
8* symbol rate 1250 Msymbols
16* symbol rate 625 Msymbols
32* symbol rate 312.5 Msymbols
64* symbol rate 156.25 Msymbols
128* symbol rate 78.125 Msymbols
4.2.1 Sample rate and maximum usable I/Q bandwidth for RF input
Definitions
●
Input sample rate (ISR): the sample rate of the useful data provided by the device
connected to the input of the R&S FSV/A
●
(User, Output) Sample rate (SR): the user-defined sample rate (e.g. in the "Data
Acquisition" dialog box in the "I/Q Analyzer" application) which is used as the basis
for analysis or output
●
Usable I/Q (Analysis) bandwidth: the bandwidth range in which the signal
remains undistorted in regard to amplitude characteristic and group delay; this
range can be used for accurate analysis by the R&S FSV/A
●
Record length: Number of I/Q samples to capture during the specified measure-
ment time; calculated as the measurement time multiplied by the sample rate
For the I/Q data acquisition, digital decimation filters are used internally in the
R&S FSV/A. The passband of these digital filters determines the maximum usable I/Q
bandwidth. In consequence, signals within the usable I/Q bandwidth (passband)
remain unchanged, while signals outside the usable I/Q bandwidth (passband) are
suppressed. Usually, the suppressed signals are noise, artifacts, and the second IF
side band. If frequencies of interest to you are also suppressed, try to increase the output sample rate, which increases the maximum usable I/Q bandwidth.
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Measurement basics
Sample rate, symbol rate and I/Q bandwidth
Bandwidth extension options
You can extend the maximum usable I/Q bandwidth provided by the R&S FSV/A in the
basic installation by adding options. These options can either be included in the initial
installation (B-options) or updated later (U-options). The maximum bandwidth provided
by the individual option is indicated by its number, for example, B40 extends the bandwidth to 40 MHz.
Note that the U-options as of U40 always require all lower-bandwidth options as a prerequisite, while the B-options already include them.
As a rule, the usable I/Q bandwidth is proportional to the output sample rate. Yet, when
the I/Q bandwidth reaches the bandwidth of the analog IF filter (at very high output
sample rates), the curve breaks.
● Bandwidth extension options.................................................................................. 79
● Relationship between sample rate, record length and usable I/Q bandwidth......... 79
● R&S FSV/A without additional bandwidth extension options.................................. 80
● R&S FSV/A with I/Q bandwidth extension option B40 or U40................................ 81
● R&S FSV/A with I/Q bandwidth extension option B200.......................................... 81
● R&S FSV/A with I/Q bandwidth extension option B400.......................................... 81
● R&S FSV/A with I/Q bandwidth extension option B600.......................................... 82
● R&S FSV/A with I/Q bandwidth extension option B1000........................................ 82
4.2.1.1 Bandwidth extension options
Max. usable I/Q BW Required B-option Required U-options
40 MHz B40
200 MHz B200
400 MHz B400 B200+U400
600 MHz B600
1000 MHz B1000 B600+U1006
4.2.1.2 Relationship between sample rate, record length and usable I/Q bandwidth
Up to the maximum bandwidth, the following rule applies:
Usable I/Q bandwidth = 0.8 * Output sample rate
Regarding the record length, the following rule applies:
Record length = Measurement time * sample rate
Maximum record length for RF input
The absolute maximum record length (AbsMaxRecordLength), that is, the maximum
number of samples that can be captured, is 100 Msamples (with option B114:
800 Msamples).
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Measurement basics
Sample rate, symbol rate and I/Q bandwidth
When using bandwidth extension options R&S FSV3-B600/-B1000, the maximum
record length depends on the analysis bandwidth.
Table 4-2: Maximum record length with I/Q bandwidth extension option B600/B1000
Analysis bandwidth *)
80 Hz to 400 MHz <Capture-
400 MHz to
800 MHz
(B600: 400 MHz to
600 MHz)
>800 MHz to 1000
MHz
*) If you restrict the maximum bandwidth to 40 MHz, 200 MHz, or 400 MHz manually ("Maximum Band-
width" on page 208), the maximum record length is AbsMaxRecordLength.
Max. meas time Maximum record length
AbsMaxRecordLength
Length> /
<SampleRate>
<CaptureLength> /
<SampleRate>
with B114:
819.2 ms
<CaptureLength> /
<SampleRate>
with B114:
409.6 ms
AbsMaxRecordLength * <SampleRate> / (1024*106)
For sample rates ≥2048 MHz: AbsMaxRecordLength
AbsMaxRecordLength * <SampleRate> / (2048*106)
For sample rates ≥2048 MHz: AbsMaxRecordLength
4.2.1.3 R&S FSV/A without additional bandwidth extension options
Sample rate: 100 Hz - 10 GHz
Maximum I/Q bandwidth: 28 MHz
Table 4-3: Maximum I/Q bandwidth
Sample rate Maximum I/Q bandwidth
100 Hz to 35 MHz Proportional up to maximum 28 MHz
35 MHz to 10 GHz 28 MHz
Usable I/Q
Bandwidth [MHz]
28
21
14
7
5
Figure 4-6: Relationship between maximum usable I/Q bandwidth and output sample rate without
bandwidth extensions
RF-Input:
BW = 0.80 * f
out
...
353025201510
25
Without BW
extension options
Output sample
10000
rate f
out
[MHz]
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Sample rate, symbol rate and I/Q bandwidth
I/Q bandwidths for RF input
Usable I/Q
Bandwidth [MHz]
1000
900
800
700
600
500
400
300
200
100
40
50
125
Figure 4-7: Relationship between maximum usable I/Q bandwidth and output sample rate with
RF-Input:
BW = 0.80 * f
optional bandwidth extensions
out
...
1250
11251000875750625500375250
10000
4.2.1.4 R&S FSV/A with I/Q bandwidth extension option B40 or U40
Sample rate: 100 Hz - 10 GHz
Activated option
B1000
Activated option
B600
Activated option
B400
Activated option
B200
Activated option
B40
Output sample
out
[MHz]
rate f
Maximum bandwidth: 40 MHz
Sample rate Maximum I/Q bandwidth
100 Hz to 50 MHz Proportional up to maximum 40 MHz
50 MHz to 10 GHz 40 MHz
4.2.1.5 R&S FSV/A with I/Q bandwidth extension option B200
Sample rate: 100 Hz - 10 GHz
Maximum bandwidth: 200 MHz
Sample rate Maximum I/Q bandwidth
100 Hz to 250 MHz Proportional up to maximum 200 MHz
250 MHz to 10 GHz 200 MHz
4.2.1.6 R&S FSV/A with I/Q bandwidth extension option B400
Sample rate: 100 Hz - 10 GHz
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4.2.1.7 R&S FSV/A with I/Q bandwidth extension option B600
Measurement basics
Symbol mapping
Maximum bandwidth: 400 MHz
Sample rate Maximum I/Q bandwidth
100 Hz to 250 MHz Proportional up to maximum 200 MHz
250 MHz to 10 GHz 200 MHz
Sample rate: 100 Hz - 10 GHz
Maximum bandwidth: 600 MHz
Note that using the bandwidth extension option R&S FSV3-B600, an I/Q bandwidth
larger than 400 MHz is only available for frequency ranges above 7.5 GHz.
Center frequency Sample rate Maximum I/Q bandwidth
≤7.5 GHz 100 Hz to 500 MHz Proportional up to maximum 400 MHz
500 MHz to 10 GHz 400 MHz
>7.5 GHz 100 Hz to 750 MHz Proportional up to maximum 600 MHz
750 MHz to 10 GHz 600 MHz
4.2.1.8 R&S FSV/A with I/Q bandwidth extension option B1000
Sample rate: 100 Hz - 10 GHz
Maximum bandwidth: 1000 MHz
Note that using the bandwidth extension option R&S FSV3-B1000, an I/Q bandwidth
larger than 400 MHz is only available for frequency ranges above 7.5 GHz.
Center frequency Sample rate Maximum I/Q bandwidth
≤7.5 GHz 100 Hz to 500 MHz Proportional up to maximum 400 MHz
500 MHz to 10 GHz 400 MHz
>7.5 GHz 100 Hz to 1250 MHz Proportional up to maximum 1000 MHz
1250 MHz to 10 GHz 1000 MHz
4.3 Symbol mapping
Mapping or symbol mapping means that symbol numbers are assigned to constellation
points or transitions in the I/Q plane (e.g. PSK and QAM).
In the analyzer, the mapping is required to decode the transmitted symbols from the
sampled I/Q or frequency/time data records.
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4.3.1 Phase shift keying (PSK)
Measurement basics
Symbol mapping
The mappings for all standards used in the analyzer and for all employed modulation
modes are described in the following. Unless indicated otherwise, symbol numbers are
specified in hexadecimal form (MSB at the left).
● Phase shift keying (PSK)........................................................................................ 83
● Rotating PSK...........................................................................................................87
● Differential PSK.......................................................................................................90
● Rotating differential PSK modulation...................................................................... 91
● Offset QPSK............................................................................................................93
● Shaped offset QPSK...............................................................................................94
● Frequency shift keying (FSK)..................................................................................95
● Minimum shift keying (MSK)................................................................................. 100
● Quadrature amplitude modulation (QAM)............................................................. 101
● ASK....................................................................................................................... 113
● APSK.....................................................................................................................114
● User-defined modulation....................................................................................... 115
With this type of modulation, the information is represented by the absolute phase
position of the received signal at the decision points. All transitions in the I/Q diagram
are possible. The complex constellation diagram is shown. The symbol numbers are
entered in the diagram according to the mapping rule.
BPSK (NATURAL, SMx)
0 1
Figure 4-8: Constellation diagram for BPSK including the symbol mapping
BPSK (NATURAL) is the BPSK mapping used by supported R&S SMx signal generators when using PRBS algorithms. See "Symbol mapping in accordance with the PRBS
generator" on page 157.
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QPSK
2
3
Figure 4-9: Constellation diagram for QPSK including the symbol mapping for CDMA2000 FWD, DVB-
S2 and DVB-RCS2
1
3
0
1
0
2
Figure 4-10: Constellation diagram for QPSK (GRAY) including the symbol mapping
0 1
2 3
Figure 4-11: Constellation diagram for QPSK (NATURAL, SMx) including the symbol mapping
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Symbol mapping
QPSK (NATURAL) is the QPSK mapping used by supported R&S SMx signal generators when using PRBS algorithms. See "Symbol mapping in accordance with the PRBS
generator" on page 157.
1
3
2
Figure 4-12: Constellation diagram for QPSK including the symbol mapping for WCDMA
0
8PSK
3
1 2
6
7
0
4
5
Figure 4-13: Constellation diagram for 8PSK (GRAY) including the symbol mapping
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Symbol mapping
2
3
4
5
6
Figure 4-14: Constellation diagram for 8PSK (NATURAL, SMx) including the symbol mapping
1
0
7
Figure 4-15: Constellation diagram for 8PSK including the symbol mapping for DVB-RCS2
8PSK (NATURAL) is the 8PSK mapping used by supported R&S SMx signal generators when using PRBS algorithms. See "Symbol mapping in accordance with the PRBS
generator" on page 157.
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Symbol mapping
4
6
3
Figure 4-16: Constellation diagram for 8PSK including the symbol mapping for DVB-S2
4.3.2 Rotating PSK
A rotating PSK modulation is basically a PSK modulation in which additional phase
shifts occur. These phase shifts depend on the symbol number, e.g. for a π/4-QPSK,
the third symbol has an additional phase offset of (3-1)*π/4. This offset has the same
effect as a rotation of the basic system of coordinates by the offset angle after each
symbol.
The method is highly important in practical applications because it prevents signal transitions through the zeros in the I/Q plane. This reduces the dynamic range of the
modulated signal and the linearity requirements for the amplifier.
0
1 2
5
7
In practice, the method is used for 3π/8-8PSK, for example, and (in conjunction with
phase-differential coding) for π/4-DQPSK.
Symbol mapping
The logical constellation diagram for 3π/8-8PSK comprises 8 points that correspond to
the modulation level (see Figure 4-17). A counter-clockwise offset (rotation) of 3π/8 is
inserted after each symbol transition.
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Symbol mapping
2
0
1
5 6
4
Figure 4-17: Constellation diagram for 3π/8 8PSK before rotation including the symbol mapping for
EDGE
3
7
Figure 4-18: I/Q symbol stream after 3π/8 rotation in I/Q plane if the symbol number "7" is transmitted
Figure 4-19: Constellation diagram for 3π/4 QPSK including the symbol mapping for EDGE
six times in a row
2
3
0
1
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Symbol mapping
1
2
0
3
Figure 4-20: Constellation diagram for π/4 QPSK (Natural) including the symbol mapping
1
3
2
Figure 4-21: Constellation diagram forπ/4 QPSK (GRAY) including the symbol mapping
0
0 1
Figure 4-22: Constellation diagram for π/2 BPSK (Natural, DVB-RCS2) and -π/2 BPSK including the
symbol mapping
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4.3.3 Differential PSK
Measurement basics
Symbol mapping
With differential PSK, the information is represented in the phase shift between two
consecutive decision points. The absolute position of the complex sample value at the
decision point does not carry information.
In the physical constellation diagram, the constellation points at the symbol decision
points obtained after ISI-free demodulation are shown (as with common PSK methods). This diagram corresponds to the display on the analyzer. The position of the constellation points is standard-specific. For example, some QPSK standards define the
constellation points on the diagonals, while other standards define the coordinate axes.
In Table 4-4, the symbols are assigned to phase shifts. The QPSK (INMARSAT) map-
ping corresponds to simple QPSK with phase-differential coding.
Tables Table 4-5 and Table 4-6 show two types of differential 8PSK modulation.
Differential coding according to VDL is shown in Table 4-7. It can be used for modula-
tion types with 3 bits/symbol, e.g. 8PSK.
Other types of modulation using differential coding method are described in Chap-
ter 4.3.4, "Rotating differential PSK modulation", on page 91.
Figure 4-23: Constellation diagram for DQPSK (INMARSAT and NATURAL) including the symbol map-
Table 4-4: DQPSK (INMARSAT)
Logical symbol mapping
Modulation symbol (binary indication: MSB, LSB) 00 01 10 11
Phase shift 0° -90° +90° 180°
ping
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Symbol mapping
Figure 4-24: Constellation diagram for D8PSK including the symbol mapping for APCO25, APCO25
Table 4-5: D8PSK (NATURAL)
Logical symbol mapping
Modulation symbol (binary indication: MSB, LSB)
Phase shift 0° 45° 90° 135° 180° 225° 270° 315°
Table 4-6: D8PSK (GRAY)
Logical symbol mapping
Modulation symbol (binary indication: MSB, LSB)
Phase shift 0° 45° 135° 90° 270° 315° 225° 180°
Table 4-7: D8PSK (VDL)
Logical symbol mapping
Modulation symbol (binary indication: MSB, LSB)
Phase shift 0° 45° 135° 90° 315° 270° 180° 225°
Phase 2, GRAY, NATURAL and TETRA
000 001 010 011 100 101 110 111
000 001 010 011 100 101 110 111
000 001 010 011 100 101 110 111
4.3.4 Rotating differential PSK modulation
Phase-differential modulation is frequently combined with an additional phase shift
(e.g. π/4 DQPSK = π/4 phase shift modulation + differential modulated 4PSK).
The logical mapping diagram corresponds to the diagram for DPSK.
The physical constellation diagram shows the symbol decision points obtained after
ISI-free demodulation.
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Symbol mapping
Figure 4-25: Constellation diagram for π/4 DQPSK including the symbol mapping for APCO25 Phase
Table 4-8: π/4 DQPSK (NADC, PDC, PHS, TETRA)
Logical symbol mapping
Modulation symbol (binary indication: MSB, LSB) 00 01 10 11
Phase shift 0°+45° 90°+45° -90°+45° -180°+45°
Table 4-9: π/4 DQPSK (TFTS)
Logical symbol mapping
Modulation symbol (binary indication: MSB, LSB) 00 01 10 11
Phase shift -180°+45° 90°+45° -90°+45° 0°+45°
Table 4-10: π/4 DQPSK (NATURAL, SMx)
Logical symbol mapping
Modulation symbol (binary indication: MSB, LSB) 00 01 10 11
Phase shift 0°+45° 90°+45° -180°+45° -90°+45°
Table 4-11: π/4 DQPSK (APCO25 and APCO25Phase2)
2, NADC, NATURAL, PDC, PHS, TETRA and TFTS; the π/4 rotation is already compensated for
Logical symbol mapping
Modulation symbol (binary indication: MSB, LSB) 00 01 10 11
Phase shift 0°+45° 90°+45° -90°+45° -180°+45°
Table 4-12: π/2 DBPSK
Logical symbol mapping
Modulation symbol (binary indication: MSB, LSB) 0 1
Phase shift 0°+90° -180°+90°
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4.3.5 Offset QPSK
Measurement basics
Symbol mapping
Offset QPSK differs from "normal" QPSK in the fact that the Q component is delayed
by half a symbol period against the I component in the time domain. Hence, the symbol
time instants of the I and the Q component do not coincide. The concept of Offset
QPSK is illustrated in the diagrams below.
Derivation of OQPSK
Table 4-13: I/Q diagram and constellation diagram
QPSK OQPSK (delayed Q component)
2
1
0
Inphase
-1
-2
0 1 2 3 4 5 6 7 8 9
2
1
re
0
Quadratu
-1
-2
0 1 2 3 4 5 6 7 8 9
Time
[symbols]
1
0
1
0
2
1
e
0
Inphas
-1
-2
0 1 2 3 4 5 6 7 8 9
2
1
e
0
Quadratur
-1
-2
0 1 2 3 4 5 6 7 8 9
Time
[symbols]
PSK vector diagram with alpha = 0.35 OQPSK vector diagram with alpha = 0.35
2
1
0
Quadrature
-1
2
1
0
Quadrature
-1
1
0
1
0
-2
-2 -1 0 1 2
Inphase
-2
-2 -1 0 1 2
Inphase
Offset QPSK reduces the dynamic range of the modulated signal (compared to "normal" QPSK) and, therefore, the demands on amplifier linearity by avoiding zero crossings.
A distinction is made in the analyzer display:
In the "Vector I/Q" result display of the measurement (or reference) signal, the time
delay is not compensated for. The display corresponds to the physical diagram shown
in (Table 4-13)
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Symbol mapping
In the "Constellation I/Q" result display of the measurement (or reference) signal, the
time delay is compensated for. The display corresponds to the logical mapping as in
Figure 4-26.
OQPSK
2
3
Figure 4-26: Constellation diagram for OQPSK (GRAY) including the symbol mapping
0
1
0 1
2 3
Figure 4-27: Constellation diagram for OQPSK (NATURAL, SMx) including the symbol mapping
OQPSK (NATURAL) is the OQPSK mapping used by supported R&S SMx signal generators when using PRBS algorithms. See "Symbol mapping in accordance with the
PRBS generator" on page 157.
4.3.6 Shaped offset QPSK
Shaped Offset QPSK is a constant envelope modulation whose phase at any instant in
time is either stationary or is moving at a rate of one-quarter of the bit rate. It can therefore also be interpreted as a ternary CPM.
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Symbol mapping
2
3
Figure 4-28: Constellation diagram for Shaped Offset QPSK including the symbol mapping
0
1
4.3.7 Frequency shift keying (FSK)
To illustrate symbol mappings for FSK modulations, the symbol numbers are marked in
the logical mapping diagram versus the instantaneous frequency. An instantaneous
frequency of zero in the baseband corresponds to the input frequency of the analyzer.
2FSK (NATURAL)
With 2FSK, the symbol decision is made by a simple frequency discriminator:
Symbol
Numbers
1
1
-1
0
Figure 4-29: Constellation diagram for 2FSK (NATURAL, SMx) including the logical symbol mapping
2FSK (NATURAL) is the 2FSK mapping used by supported R&S SMx signal generators when using PRBS algorithms. See "Symbol mapping in accordance with the PRBS
generator" on page 157.
4FSK
With 4FSK, the symbol decision is made by a frequency discriminator with 3 decision
thresholds (-2/3; 0; +2/3) normalized to the FSK reference deviation.
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Symbol mapping
13
Symbol
Numbers
1/3
2
-1/3
1
-10
Figure 4-30: Constellation diagram for 4FSK (NATURAL, SMx) including the logical symbol mapping
4FSK (NATURAL) is the 4FSK mapping used by supported R&S SMx signal generators when using PRBS algorithms. See "Symbol mapping in accordance with the PRBS
generator" on page 157.
12
Symbol
Numbers
1/3
3
-1/3
1
-10
Figure 4-31: Constellation diagram for 4FSK (GRAY) including the logical symbol mapping
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Symbol
Numbers
Measurement basics
Symbol mapping
11
1/3
0
-1/3
2
-13
Figure 4-32: Constellation diagram for 4FSK for APCO C4FM and APCO Phase 2 including the logical
symbol mapping
8FSK (NATURAL)
17
5/7
6
3/7
Symbol
Numbers
Figure 4-33: Constellation diagram for 8FSK (NATURAL) including the logical symbol mapping
5
1/74
-1/73
-3/7
2
-5/7
1
-10
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Symbol mapping
16 FSK
Figure 4-34: Constellation diagram for 16FSK including the logical symbol mapping
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32FSK
Figure 4-35: Constellation diagram for 32FSK including the logical symbol mapping
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64FSK
Figure 4-36: Constellation diagram for 64FSK including the logical symbol mapping
4.3.8 Minimum shift keying (MSK)
MSK modulation causes modulation-dependent phase shifts of +/- 90° which can be
shown in a "Constellation I/Q" diagram. As with PSK, the phase positions are evaluated during demodulation.
Table 4-14: MSK (NATURAL)
Logical symbol mapping
Modulation symbol (binary indication: MSB, LSB) 0 1
Phase shift -90° +90°
Table 4-15: MSK (GSM)
Logical symbol mapping
Modulation symbol (binary indication: MSB, LSB) 0 1
Phase shift +90° -90°
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