Rohde & Schwarz FPL1-K70 User Manual
R&S®FPL1-K70
Vector Signal Analysis
User Manual
(;ÜëË2)
1178936102
User Manual
Version 02
This manual applies to the following R&S®FPL1000 models with firmware version 1.30 and higher:
●
R&S®FPL1003 (1304.0004K03) - FPL1000 with maximum frequency 3 GHz
●
R&S®FPL1007 (1304.0004K07) - FPL1000 with maximum frequency 7.5 GHz
The following firmware options are described:
●
R&S FPL1000-K70 (1323.1748.02)
●
R&S FPL1000-K70P (1323.1631.02)
●
R&S FPL1000-K70M (1323.1625.02)
© 2019 Rohde & Schwarz GmbH & Co. KG
Mühldorfstr. 15, 81671 München, Germany
Phone: +49 89 41 29 - 0
Fax: +49 89 41 29 12 164
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.
1178.9361.02 | Version 02 | R&S®FPL1-K70
Throughout this manual, products from Rohde & Schwarz are indicated without the ® symbol, e.g. R&S®FPL1000 is indicated as
R&S FPL1000.
R&S®FPL1-K70
1 Preface.................................................................................................... 7
1.1 Documentation Overview............................................................................................. 7
1.2 Conventions Used in the Documentation...................................................................9
2 Welcome to the Vector Signal Analysis Application.........................11
2.1 Introduction to Vector Signal Analysis..................................................................... 12
2.2 Starting the VSA Application..................................................................................... 12
2.3 Understanding the Display Information....................................................................13
3 Measurements and Result Displays...................................................16
3.1 Evaluation Data Sources in VSA............................................................................... 16
3.2 Result Types in VSA....................................................................................................20
Contents
Contents
3.3 Predefined Display Configuration............................................................................. 59
3.4 Common Parameters in VSA..................................................................................... 60
4 Measurement Basics........................................................................... 63
4.1 Filters and Bandwidths during Signal Processing.................................................. 63
4.2 Sample Rate, Symbol Rate and I/Q Bandwidth........................................................ 70
4.3 Symbol Mapping......................................................................................................... 73
4.4 Overview of the Demodulation Process................................................................. 105
4.5 Signal Model, Estimation and Modulation Errors.................................................. 119
4.6 Measurement Ranges............................................................................................... 136
4.7 Display Points Vs Estimation Points Per Symbol..................................................141
4.8 Capture Buffer Display............................................................................................. 142
4.9 Known Data Files - Dependencies and Restrictions............................................. 142
4.10 Known Data from PRBS Generators....................................................................... 144
4.11 Multi-Modulation Analysis (R&S FPL1000-K70M)..................................................146
5 Configuration......................................................................................153
5.1 Configuration Overview............................................................................................153
5.2 Configuration According to Digital Standards.......................................................157
5.3 Signal Description.....................................................................................................159
5.4 Input, Output and Frontend Settings.......................................................................177
5.5 Signal Capture...........................................................................................................191
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5.6 Burst and Pattern Configuration............................................................................. 199
5.7 Result Range Configuration.....................................................................................209
5.8 Demodulation Settings............................................................................................. 211
5.9 Measurement Filter Settings.................................................................................... 220
5.10 Evaluation Range Configuration............................................................................. 222
5.11 Adjusting Settings Automatically............................................................................223
5.12 Restoring Factory Settings for Vector Signal Analysis.........................................225
6 Analysis.............................................................................................. 227
6.1 Trace Settings............................................................................................................227
6.2 Trace Export Settings............................................................................................... 230
6.3 Markers...................................................................................................................... 232
6.4 Limit and Display Lines............................................................................................ 237
Contents
6.5 Display and Window Configuration.........................................................................241
7 I/Q Data Import and Export................................................................246
7.1 Import/Export Functions.......................................................................................... 246
7.2 How to Export and Import I/Q Data..........................................................................248
8 How to Perform Vector Signal Analysis...........................................251
8.1 How to Perform VSA According to Digital Standards........................................... 251
8.2 How to Perform Customized VSA Measurements................................................. 253
8.3 How to Analyze the Measured Data.........................................................................265
9 Measurement Examples.................................................................... 272
9.1 Connecting the Transmitter and Analyzer..............................................................272
9.2 Measurement Example 1: Continuous QPSK Signal............................................. 273
9.3 Measurement Example 2: Burst GSM EDGE Signals............................................ 280
10 Troubleshooting the Measurement.................................................. 289
10.1 Flow Chart for Troubleshooting...............................................................................289
10.2 Explanation of Status Bar Messages...................................................................... 291
10.3 Frequently Asked Questions................................................................................... 300
10.4 Collecting Information for Support..........................................................................310
11 Remote Commands for VSA............................................................. 312
11.1 Introduction............................................................................................................... 312
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11.2 Common Suffixes......................................................................................................317
11.3 Activating Vector Signal Analysis........................................................................... 317
11.4 Digital Standards.......................................................................................................321
11.5 Configuring VSA....................................................................................................... 323
11.6 Performing a Measurement......................................................................................398
11.7 Analysis..................................................................................................................... 402
11.8 Configuring the Result Display................................................................................425
11.9 Retrieving Results.....................................................................................................439
11.10 Importing and Exporting I/Q Data and Results...................................................... 463
11.11 Status Reporting System......................................................................................... 464
11.12 Deprecated Commands............................................................................................475
11.13 Programming Examples...........................................................................................476
Contents
Annex.................................................................................................. 485
A Abbreviations..................................................................................... 485
B Predefined Standards and Settings................................................. 486
C Predefined Measurement and Tx Filters.......................................... 494
C.1 Transmit Filters......................................................................................................... 494
C.2 Measurement Filters................................................................................................. 495
C.3 Typical Combinations of Tx and Measurement Filters.......................................... 496
D ASCII File Export Format for VSA Data............................................497
E Known Data File Syntax Description................................................499
F Formulae.............................................................................................501
F.1 Trace-based Evaluations.......................................................................................... 501
F.2 Result Summary Evaluations...................................................................................503
F.3 Statistical Evaluations for the Result Summary.................................................... 506
F.4 Trace Averaging........................................................................................................ 507
F.5 Analytically Calculated Filters................................................................................. 507
F.6 Standard-Specific Filters.......................................................................................... 508
G I/Q Data File Format (iq-tar)...............................................................515
G.1 I/Q Parameter XML File Specification......................................................................516
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G.2 I/Q Data Binary File................................................................................................... 519
Contents
List of Remote Commands (VSA).....................................................521
Index....................................................................................................532
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1 Preface
1.1 Documentation Overview
1.1.1 Getting Started Manual
Preface
Documentation Overview
This chapter provides safety-related information, an overview of the user documentation and the conventions used in the documentation.
This section provides an overview of the R&S FPL1000 user documentation. Unless
specified otherwise, you find the documents on the R&S FPL1000 product page at:
www.rohde-schwarz.com/manual/FPL1000
Introduces the R&S FPL1000 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.
1.1.2 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 FPL1000 is
not included.
The contents of the user manuals are available as help in the R&S FPL1000. 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.
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1.1.3 Service Manual
1.1.4 Instrument Security Procedures
1.1.5 Basic Safety Instructions
Preface
Documentation Overview
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.
The service manual is available for registered users on the global Rohde & Schwarz
information system (GLORIS):
https://gloris.rohde-schwarz.com
Deals with security issues when working with the R&S FPL1000 in secure areas. It is
available for download on the Internet.
Contains safety instructions, operating conditions and further important information.
The printed document is delivered with the instrument.
1.1.6 Data Sheets and Brochures
The data sheet contains the technical specifications of the R&S FPL1000. 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/FPL1000
1.1.7 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/FPL1000
1.1.8 Application Notes, Application Cards, White Papers, etc.
These documents deal with special applications or background information on particular topics.
See www.rohde-schwarz.com/application/FPL1000
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1.1.9 Calibration Certificate
1.2 Conventions Used in the Documentation
1.2.1 Typographical Conventions
Preface
Conventions Used in the Documentation
The document is available on https://gloris.rohde-schwarz.com/calcert. You need the
device ID of your instrument, which you can find on a label on the rear panel.
The following text markers are used throughout this documentation:
Convention Description
"Graphical user interface elements"
[Keys] Key and knob names are enclosed by square brackets.
Filenames, commands,
program code
Input Input to be entered by the user is displayed in italics.
Links Links that you can click are displayed in blue font.
"References" References to other parts of the documentation are enclosed by quota-
All names of graphical user interface elements on the screen, such as
dialog boxes, menus, options, buttons, and softkeys are enclosed by
quotation marks.
Filenames, commands, coding samples and screen output are distinguished by their font.
tion marks.
1.2.2 Conventions for Procedure Descriptions
When operating the instrument, several alternative methods may be available to perform the same task. In this case, the procedure using the touchscreen is described.
Any elements that can be activated by touching can also be clicked using an additionally connected mouse. The alternative procedure using the keys on the instrument or
the on-screen keyboard is only described if it deviates from the standard operating procedures.
The term "select" may refer to any of the described methods, i.e. using a finger on the
touchscreen, a mouse pointer in the display, or a key on the instrument or on a keyboard.
1.2.3 Notes on Screenshots
When describing the functions of the product, we use sample screenshots. These
screenshots are meant to illustrate as many as possible of the provided functions and
possible interdependencies between parameters. The shown values may not represent
realistic usage scenarios.
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Preface
Conventions Used in the Documentation
The screenshots usually show a fully equipped product, that is: with all options installed. Thus, some functions shown in the screenshots may not be available in your particular product configuration.
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2 Welcome to the Vector Signal Analysis
Welcome to the Vector Signal Analysis Application
Application
The R&S FPL1-K70 is a firmware application that adds functionality to perform Vector
Signal Analysis (VSA) to the R&S FPL1000.
The R&S FPL1000 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 FPL1000 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.
The R&S FPL1000 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.
Functions that are not discussed in this manual are the same as in the Spectrum application and are described in the R&S FPL1000 User Manual. The latest version is available for download at the product homepage
http://www.rohde-schwarz.com/product/FPL1000.html.
Additional information
Several application notes discussing vector signal analysis using the R&S FPL1000
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
Installation
You can find detailed installation instructions in the R&S FPL1000 Getting Started manual or in the Release Notes.
● Introduction to Vector Signal Analysis.....................................................................12
● Starting the VSA Application...................................................................................12
● Understanding the Display Information...................................................................13
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2.1 Introduction to Vector Signal Analysis
Welcome to the Vector Signal Analysis Application
Starting the VSA Application
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 FPL1000 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
2.2 Starting the VSA Application
The VSA application adds a new application to the R&S FPL1000.
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 FPL1000.
2. Select the "VSA" item.
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Welcome to the Vector Signal Analysis Application
Understanding the Display Information
The R&S FPL1000 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 153).
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, in order 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 FPL1000 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 Vector Signal Analysis Application
Understanding the Display Information
1
2 3
4
5
6
1 = Channel bar for firmware and measurement settings
2+3 = Window title bar with diagram-specific (trace) information
4 = Diagram area
5 = Diagram footer with diagram-specific information, depending on measurement application
6 = Instrument status bar with error messages, progress bar and date/time display
Channel bar information
In VSA application, the R&S FPL1000 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)
Freq Center frequency for the RF signal
Std Selected measurement standard or, if no standard selected, modulation
type or loaded user-defined modulation file
Res Len Result Length
Cap Len Capture Length (instead of result length for capture buffer display), see
"Capture Length Settings" on page 193
SR Symbol Rate
Att Mechanical and electronic RF attenuation
Input Input type of the signal source, see Chapter 5.4.1, "Input Settings",
on page 177
Burst Burst search active (see "Enabling Burst Searches" on page 200)
Pattern Pattern search active (see "Enabling Pattern Searches" on page 203)
Equalizer Equalizer active (see "Equalizer Settings" on page 214)
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Welcome to the Vector Signal Analysis Application
Understanding the Display Information
Stat Count Statistics count for averaging and other statistical operations, see "Statis-
tic Count" on page 198; cannot be edited directly
Capt Count Capture count; the current number of captures performed if several cap-
tures are necessary to obtain the number of results defined by "Statistics
Count"; cannot be edited directly
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 FPL1000 Getting Started manual.
Window title bar information
For each diagram, the header provides the following information:
Figure 2-2: Window title bar information in VSA application
1 = Window name
2 = Result type
3 = Data source type
4 = Trace color
5 = Displayed signal for Meas&Ref or multi data source: M (Meas), R (Ref), C (Capture buffer), E (Error)
6 = Trace mode
Diagram area
The diagram area displays the results according to the selected result displays (see
Chapter 3, "Measurements and Result Displays", on page 16).
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
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 136.)
● Evaluation Data Sources in VSA.............................................................................16
● Result Types in VSA............................................................................................... 20
● Predefined Display Configuration............................................................................59
● Common Parameters in VSA..................................................................................60
3.1 Evaluation Data Sources in VSA
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 241.
In diagrams in the frequency domain (Spectrum transformation, see "Result Type
Transformation" on page 243) the usable I/Q bandwidth is indicated by vertical blue
lines.
Capture Buffer...............................................................................................................17
Measurement & Reference Signal................................................................................ 17
Symbols........................................................................................................................ 18
Error Vector...................................................................................................................18
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Measurements and Result Displays
Evaluation Data Sources in VSA
Modulation Errors..........................................................................................................18
Modulation Accuracy.....................................................................................................19
Equalizer....................................................................................................................... 19
Multi Source.................................................................................................................. 19
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 by dragging 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 42
●
Chapter 3.2.27, "Real/Imag (I/Q)", on page 48
●
Chapter 3.2.11, "Frequency Absolute", on page 32
●
Chapter 3.2.33, "Vector I/Q", on page 58
Remote command:
LAY:ADD? '1',BEL,TCAP(see LAYout:ADD[:WINDow]? on page 426)
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 42
●
Chapter 3.2.22, "Magnitude Relative", on page 43
●
Chapter 3.2.25, "Phase Wrap", on page 46
●
Chapter 3.2.26, "Phase Unwrap", on page 47
●
Chapter 3.2.11, "Frequency Absolute", on page 32
●
Chapter 3.2.12, "Frequency Relative", on page 34
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Measurements and Result Displays
Evaluation Data Sources in VSA
●
Chapter 3.2.27, "Real/Imag (I/Q)", on page 48
●
Chapter 3.2.10, "Eye Diagram Real (I)", on page 31
●
Chapter 3.2.9, "Eye Diagram Imag (Q)", on page 30
●
Chapter 3.2.8, "Eye Diagram Frequency", on page 30
●
Chapter 3.2.5, "Constellation I/Q", on page 26
●
Chapter 3.2.33, "Vector I/Q", on page 58
●
Chapter 3.2.4, "Constellation Frequency", on page 25
●
Chapter 3.2.32, "Vector Frequency", on page 57
Remote command:
LAY:ADD? '1',BEL,REF(see LAYout:ADD[:WINDow]? on page 426)
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 3.2.31, "Symbol Table", on page 56).
Remote command:
LAY:ADD? '1',BEL, SYMB(see LAYout:ADD[:WINDow]? on page 426)
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 29
●
Chapter 3.2.27, "Real/Imag (I/Q)", on page 48
●
Chapter 3.2.33, "Vector I/Q", on page 58
Remote command:
LAY:ADD? '1',BEL,EVEC(see LAYout:ADD[:WINDow]? on page 426)
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 42
●
Chapter 3.2.24, "Phase Error", on page 45
●
Chapter 3.2.13, "Frequency Error Absolute", on page 35
●
Chapter 3.2.14, "Frequency Error Relative", on page 36
Remote command:
LAY:ADD? '1',BEL,MERR(see LAYout:ADD[:WINDow]? on page 426)
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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 3.2.28, "Result Summary", on page 49
●
Chapter 3.2.1, "Bit Error Rate (BER)", on page 22
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 426)
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 40
●
Chapter 3.2.19, "Impulse Response Phase", on page 41
●
Chapter 3.2.20, "Impulse Response Real/Imag", on page 41
●
Chapter 3.2.16, "Frequency Response Magnitude", on page 38
●
Chapter 3.2.17, "Frequency Response Phase", on page 39
●
Chapter 3.2.15, "Frequency Response Group Delay", on page 37
●
Chapter 3.2.3, "Channel Frequency Response Magnitude", on page 25
●
Chapter 3.2.2, "Channel Frequency Response Group Delay", on page 24
The default result type is "Frequency Response Magnitude".
Remote command:
LAY:ADD? '1',BEL,EQU(see LAYout:ADD[:WINDow]? on page 426)
Multi Source
Combines two data sources in one diagram, with (initially) one trace for each data
source. This 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 3.2.29, "Spectrum (Capture Buffer + Error)", on page 53
●
Chapter 3.2.30, "Spectrum (Measurement + Error)", on page 55
Remote command:
LAY:ADD? '1',RIGH,MCOM, see LAYout:ADD[:WINDow]? on page 426
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 435.
Table 3-1: Available result types depending on data source
Evaluation Data
Source
Capture Buffer Magnitude Absolute MAGNitude
Meas & Ref Signal Magnitude Absolute MAGNitude
Result Type SCPI Parameter
Real/Imag (I/Q) RIMag
Frequency Absolute FREQuency
Vector I/Q COMP
Magnitude Relative MAGNitude
Phase Wrap PHASe
Phase Unwrap UPHase
Frequency Absolute FREQuency
Frequency Relative FREQuency
Real/Imag (I/Q) RIMag
Eye Diagram Real (I) IEYE
Eye Diagram Imag (Q) QEYE
Eye Diagram Frequency FEYE
Constellation I/Q CONS
Constellation I/Q (Rotated) RCON
Vector I/Q COMP
Constellation Frequency CONF
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Measurements and Result Displays
Result Types in VSA
Evaluation Data
Source
Symbols Binary -
Error Vector EVM MAGNitude
Modulation Errors Magnitude Error MAGNitude
Modulation Accuracy Bit Error Rate BERate
Equalizer Impulse Response Magnitude MAGNitude
Result Type SCPI Parameter
Vector Frequency COVF
Octal -
Decimal -
Hexadecimal -
Real/Imag (I/Q) RIMag
Vector I/Q COMP
Phase Error PHASe
Frequency Error Absolute FREQuency
Frequency Error Relative FREQuency
Result Summary RSUM
Impulse Response Phase UPHase
Impulse Response Real/Image RIMag
Frequency Response Magnitude MAGNitude
Frequency Response Phase UPHase
Frequency Response Group Delay GDELay
Channel Frequency Response Magnitude
Channel Frequency Response Group
Delay
Multi Source Spectrum (Real/Imag) (Capture buffer
+ Error)
Spectrum (Real/Imag) (Measurement
+ Error)
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 241.
Remote command:
CALCulate<n>:FORMat on page 435
● Bit Error Rate (BER)................................................................................................22
● Channel Frequency Response Group Delay.......................................................... 24
● Channel Frequency Response Magnitude..............................................................25
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Measurements and Result Displays
Result Types in VSA
● Constellation Frequency......................................................................................... 25
● Constellation I/Q......................................................................................................26
● Constellation I/Q (Rotated)......................................................................................28
● Error Vector Magnitude (EVM)................................................................................29
● Eye Diagram Frequency......................................................................................... 30
● Eye Diagram Imag (Q)............................................................................................ 30
● Eye Diagram Real (I)...............................................................................................31
● Frequency Absolute................................................................................................ 32
● Frequency Relative................................................................................................. 34
● Frequency Error Absolute....................................................................................... 35
● Frequency Error Relative........................................................................................ 36
● Frequency Response Group Delay.........................................................................37
● Frequency Response Magnitude............................................................................ 38
● Frequency Response Phase...................................................................................39
● Impulse Response Magnitude.................................................................................40
● Impulse Response Phase....................................................................................... 41
● Impulse Response Real/Imag.................................................................................41
● Magnitude Absolute................................................................................................ 42
● Magnitude Relative................................................................................................. 43
● Magnitude Error...................................................................................................... 44
● Phase Error.............................................................................................................45
● Phase Wrap............................................................................................................ 46
● Phase Unwrap.........................................................................................................47
● Real/Imag (I/Q)........................................................................................................48
● Result Summary......................................................................................................49
● Spectrum (Capture Buffer + Error)..........................................................................53
● Spectrum (Measurement + Error)........................................................................... 55
● Symbol Table...........................................................................................................56
● Vector Frequency....................................................................................................57
● Vector I/Q................................................................................................................58
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 may 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 142).
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 FPL1000 VSA application is provided in the instrument free of charge.
See Chapter 8.2.4.2, "How to Create Known Data Files", on page 262.
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Result Types in VSA
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 FPL1000 VSA
application knows which sequences may occur. This function requires the
R&S FPL1000-K70P option. See Chapter 4.10, "Known Data from PRBS Generators",
on page 144.
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 may 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 111 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 BER 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:
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)
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3.2.2 Channel Frequency Response Group Delay
Measurements and Result Displays
Result Types in VSA
Remote commands:
LAY:ADD? '1',BEL,MACC
to define the required source type (see LAYout:ADD[:WINDow]? on page 426)
CALC:FORM BER
to define the result type (see CALCulate<n>:FORMat on page 435)
CALC:BER?
to query the results (see CALCulate<n>:BERate on page 449)
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 426)
CALC:FEED 'XFR:DDEM:IRAT'
to define the channel frequency response result type (see CALCulate<n>:FEED
on page 434)
CALC:FORM GDEL
to define the group delay result type (see CALCulate<n>:FORMat on page 435)
TRAC:DATA? TRACE1
to query the trace results (see TRACe<n>[:DATA]? TRACE<n> and Chapter 11.9.2.6,
"Equalizer", on page 448)
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3.2.3 Channel Frequency Response Magnitude
Measurements and Result Displays
Result Types in VSA
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, may 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 426)
CALC:FEED 'XFR:DDEM:IRAT'
to define the channel frequency response result type (see CALCulate<n>:FEED
on page 434)
CALC:FORM MAGN
to define the magnitude result type (see CALCulate<n>:FORMat on page 435)
TRAC:DATA? TRACE1
to query the trace results (see TRACe<n>[:DATA]? TRACE<n> and Chapter 11.9.2.6,
"Equalizer", on page 448)
3.2.4 Constellation Frequency
The instantaneous frequency of 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
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Figure 3-2: Result display "Constellation Frequency"
Remote commands:
LAY:ADD? '1',BEL,MEAS
to define the required source type (see LAYout:ADD[:WINDow]? on page 426)
CALC:FORM CONF
to define the result type (see CALCulate<n>:FORMat on page 435)
TRAC:DATA? TRACE1
to query the trace results (see TRACe<n>[:DATA]? TRACE<n> and Chapter 11.9.2.3,
"Polar Diagrams", on page 446)
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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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, while 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 FPL1000-K70M)", on page 146), 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 222).
You can alo define different colored traces for different symbol types (see Chapter 6.1,
"Trace Settings", on page 227).
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3.2.6 Constellation I/Q (Rotated)
Measurements and Result Displays
Result Types in VSA
Remote commands:
LAY:ADD? '1',BEL,MEAS
to define the required source type (see LAYout:ADD[:WINDow]? on page 426)
CALC:FORM CONS
to define the result type (see CALCulate<n>:FORMat on page 435)
TRAC:DATA? TRACE1
to query the trace results (see TRACe<n>[:DATA]? TRACE<n> and Chapter 11.9.2.3,
"Polar Diagrams", on page 446)
CALCulate<n>:MARKer<m>:Y on page 408, to query the marker I/Q values
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.
Figure 3-4: Result display "Constellation I/Q (Rotated)" vs. common "Constellation I/Q" for 3
8-8PSK modulation
Remote commands:
LAY:ADD? '1',BEL,MEAS
to define the required source type (see LAYout:ADD[:WINDow]? on page 426)
CALC:FORM RCON
π
/
to define the result type (see CALCulate<n>:FORMat on page 435)
TRAC:DATA? TRACE1
to query the trace results (see TRACe<n>[:DATA]? TRACE<n> and Chapter 11.9.2.3,
"Polar Diagrams", on page 446)
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C
tEV
tEVM
k
TkREF
K
C
2
1
periods symbol ofduration T
3.2.7 Error Vector Magnitude (EVM)
Measurements and Result Displays
Result Types in VSA
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 243).
The normalization constant C is chosen according to the EVM normalization. By
default C² is the mean power of the reference signal.
and
Note that k=0.5·n·T for Offset QPSK with inactive Offset EVM.
Figure 3-5: Result display "Error Vector Magnitude"
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 426)
CALC:FORM MAGN
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3.2.8 Eye Diagram Frequency
Measurements and Result Displays
Result Types in VSA
to define the result type (see CALCulate<n>:FORMat on page 435)
TRAC:DATA? TRACE1
to query the trace results (see TRACe<n>[:DATA]? TRACE<n> and Chapter 11.9.2.2,
"Cartesian Diagrams", on page 446)
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
Display lines are available in eye diagrams which allow you to determine the size of the
eye, see also Chapter 8.3.2, "How to Measure the Size of an Eye", on page 269.
Remote commands:
LAY:ADD? '1',BEL,MEAS
to define the required source type (see LAYout:ADD[:WINDow]? on page 426)
CALC:FORM FEYE
to define the result type (see CALCulate<n>:FORMat on page 435)
TRAC:DATA? TRACE1
to query the trace results (see TRACe<n>[:DATA]? TRACE<n> and Chapter 11.9.2.2,
"Cartesian Diagrams", on page 446)
Chapter 11.7.3, "Configuring Display Lines for Eye Diagrams", on page 416
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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