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FS-K196
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Rohde&Schwarz FS-K96, FS-K96PC, FS-K196 User Manual

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R&S® FS-K96/-K96PC/-K196 OFDM Vector Signal Analysis Software
User Manual
(=:3O2)
User Manual
Test & Measurement
This manual contains the documentation for the following products.
●
R&S®FS-K96 (1310.0202.06)
●
R&S®FS-K96PC (1310.0219.06)
●
R&S®FS-K196 (1309.9200.06)
●
R&S®FSPC (1310.0002.03)
The contents correspond to software version 3.6 and higher.
The software contained in this product makes use of several valuable open source software packages. For information, see the
"Open Source Acknowledgment" on the user documentation CD-ROM (included in delivery).
Rohde & Schwarz would like to thank the open source community for their valuable contribution to embedded computing.
© 2015 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.
The following abbreviations are used throughout this manual: R&S®FS-K96 is abbreviated as R&S FS-K96 and R&S®FS-K96 is
abbreviated as R&S FS-K96.
Quality management
Certied Quality System
ISO 9001
and environmental management
Sehr geehrter Kunde,
Sie haben sich für den Kauf eines Rohde & Schwarz Produk­tes entschieden. Sie erhalten damit ein nach modernsten Fer­tigungsmethoden hergestelltes Produkt. Es wurde nach den Regeln unserer Qualitäts- und Umweltmanagementsysteme entwickelt, gefertigt und geprüft. Rohde & Schwarz ist unter ande­rem nach den Managementsys­temen ISO 9001 und ISO 14001 zertifiziert.
Der Umwelt verpflichtet
❙ Energie-efziente,
RoHS-konforme Produkte
❙ Kontinuierliche
Weiterentwicklung nachhaltiger Umweltkonzepte
❙ ISO 14001-zertiziertes
Umweltmanagementsystem
Dear customer,
You have decided to buy a Rohde & Schwarz product. This product has been manufactured using the most advanced meth­ods. It was developed, manufac­tured and tested in compliance with our quality management and environmental manage­ment systems. Rohde & Schwarz has been certified, for exam­ple, according to the ISO 9001 and ISO 14001 management systems.
Environmental commitment
❙ Energy-efcient products ❙ Continuous improvement in
environmental sustainability
❙ ISO 14001-certied
environmental management system
Certied Environmental System
ISO 14001
Cher client,
Vous avez choisi d’acheter un produit Rohde & Schwarz. Vous disposez donc d’un produit fabriqué d’après les méthodes les plus avancées. Le dévelop­pement, la fabrication et les tests de ce produit ont été effec­tués selon nos systèmes de management de qualité et de management environnemental. La société Rohde & Schwarz a été homologuée, entre autres, conformément aux systèmes de management ISO 9001 et ISO 14001.
Engagement écologique
❙ Produits à efcience
énergétique
❙ Amélioration continue de la
durabilité environnementale
❙ Système de management
environnemental certié selon
ISO 14001
1171.0200.11 V 05.01
1171020011

Customer Support

Technical support – where and when you need it
For quick, expert help with any Rohde & Schwarz equipment, contact one of our Customer Support Centers. A team of highly qualified engineers provides telephone support and will work with you to find a solution to your query on any aspect of the operation, programming or applications of Rohde & Schwarz equipment.
Up-to-date information and upgrades
To keep your instrument up-to-date and to be informed about new application notes related to your instrument, please send an e-mail to the Customer Support Center stating your instrument and your wish. We will take care that you will get the right information.
Europe, Africa, Middle East
North America
Latin America
Asia/Pacific
China
Phone +49 89 4129 12345
customersupport@rohde-schwarz.com
Phone 1-888-TEST-RSA (1-888-837-8772)
customer.support@rsa.rohde-schwarz.com
Phone +1-410-910-7988
customersupport.la@rohde-schwarz.com
Phone +65 65 13 04 88
customersupport.asia@rohde-schwarz.com
Phone +86-800-810-8228 / +86-400-650-5896
customersupport.china@rohde-schwarz.com
1171.0200.22-06.00
R&S® FS-K96/-K96PC/-K196

Contents

1 Welcome to R&S FS-K96.......................................................................7
1.1 Installing the Software..................................................................................................7
1.1.1 Installing Required Components..................................................................................... 8
1.1.2 Installing R&S FS-K96.................................................................................................. 10
1.1.3 Deinstalling R&S FS-K96.............................................................................................. 12
1.2 Licensing the Software...............................................................................................12
1.3 Starting the Software.................................................................................................. 16
1.4 First Steps....................................................................................................................17
1.4.1 Setting up the Generator...............................................................................................17
1.4.2 Preparing the Measurement..........................................................................................18
1.4.3 Performing the Measurement........................................................................................20
Contents
2 General Configuration......................................................................... 21
2.1 Instrument Connection...............................................................................................21
2.1.1 Instrument Connection Configuration............................................................................21
2.1.2 Figuring Out IP Addresses............................................................................................ 23
2.2 Software Configuration.............................................................................................. 26
2.3 Display Configuration.................................................................................................27
2.4 Data Management....................................................................................................... 28
2.4.1 Settings......................................................................................................................... 28
2.4.2 I/Q Data.........................................................................................................................29
2.4.3 Demodulation Data....................................................................................................... 31
2.4.4 Limits.............................................................................................................................32
3 Measurements and Result Displays...................................................33
3.1 Numerical results........................................................................................................ 33
3.2 Graphical Results........................................................................................................34
3.3 I/Q Measurements....................................................................................................... 36
3.3.1 Power Measurements................................................................................................... 36
3.3.2 EVM Measurements......................................................................................................39
3.3.3 Channel Measurements................................................................................................ 43
3.3.4 Constellation Measurements.........................................................................................44
3.3.5 Statistics and Miscellaneous Measurements................................................................ 46
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3.4 Result Summary..........................................................................................................49
4 Settings.................................................................................................50
4.1 General Settings..........................................................................................................50
4.1.1 Primary Settings............................................................................................................50
4.1.2 Advanced Settings........................................................................................................ 56
4.1.3 Measurement Settings.................................................................................................. 60
4.2 Demodulation Settings............................................................................................... 63
4.2.1 Signal Description......................................................................................................... 63
4.2.2 Demodulation Control................................................................................................... 70
5 System Configuration File...................................................................75
5.1 Matlab Configuration File Format..............................................................................75
5.1.1 OFDM System Class.....................................................................................................78
Contents
5.1.2 Generate I/Q Data Files ............................................................................................... 82
5.2 XML Configuration File Format..................................................................................84
5.2.1 Overview of the R&S FS-K96 Configuration File Wizard.............................................. 86
5.2.2 Generate I/Q Data Files ............................................................................................... 93
6 Measurements in Detail.......................................................................96
6.1 General Information on Signal Types....................................................................... 96
6.1.1 OFDM............................................................................................................................96
6.1.2 GFDM..........................................................................................................................103
6.1.3 UFMC..........................................................................................................................104
6.2 Signal Processing..................................................................................................... 105
6.2.1 Data Capturing............................................................................................................ 105
6.2.2 Channel Filter..............................................................................................................106
6.2.3 OFDM Measurement...................................................................................................108
6.3 Measurement Result Definitions............................................................................. 110
6.3.1 Error Vector Magnitude (EVM)....................................................................................110
6.3.2 I/Q Impairments...........................................................................................................111
7 Remote Control.................................................................................. 112
7.1 Remote Control Setup.............................................................................................. 112
7.2 Introduction............................................................................................................... 113
7.2.1 Long and Short Form.................................................................................................. 114
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7.2.2 Numeric Suffixes......................................................................................................... 114
7.2.3 Optional Keywords...................................................................................................... 114
7.2.4 Alternative Keywords.................................................................................................. 115
7.2.5 SCPI Parameters........................................................................................................ 115
7.3 Common Commands................................................................................................ 117
7.4 Measurements........................................................................................................... 118
7.4.1 Measurement Control..................................................................................................118
7.4.2 Measurement Selection.............................................................................................. 119
7.4.3 Graphical Results........................................................................................................120
7.4.4 Numerical Results....................................................................................................... 126
7.5 Instrument Connection.............................................................................................130
7.6 Primary Settings........................................................................................................130
7.6.1 Instrument Settings..................................................................................................... 130
Contents
7.6.2 Data Capture...............................................................................................................131
7.6.3 Level Settings..............................................................................................................132
7.6.4 Trigger Settings...........................................................................................................134
7.6.5 Input Settings.............................................................................................................. 136
7.7 Advanced Settings....................................................................................................137
7.7.1 I/Q Settings................................................................................................................. 137
7.7.2 Analog Baseband Input...............................................................................................138
7.7.3 Digital I/Q Input........................................................................................................... 139
7.7.4 Advanced Level Settings.............................................................................................140
7.8 Measurement Settings..............................................................................................142
7.8.1 Units............................................................................................................................ 142
7.8.2 EVM............................................................................................................................ 145
7.9 Signal Description.....................................................................................................146
7.9.1 System Configuration..................................................................................................146
7.9.2 Symbol Characteristics............................................................................................... 147
7.9.3 Filter Characteristics................................................................................................... 149
7.9.4 Preamble Symbol Characteristics............................................................................... 150
7.10 Demodulation Control.............................................................................................. 151
7.10.1 General Settings......................................................................................................... 151
7.10.2 Synchronization Settings.............................................................................................152
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7.10.3 Compensation Settings............................................................................................... 154
7.10.4 Advanced Settings...................................................................................................... 155
7.11 File Management....................................................................................................... 156
7.12 Display Settings........................................................................................................ 158
List of Commands..............................................................................161
Index....................................................................................................164
Contents
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1 Welcome to R&S FS-K96

● Installing the Software...............................................................................................7
● Licensing the Software............................................................................................12
● Starting the Software...............................................................................................16
● First Steps...............................................................................................................17
Welcome to R&S FS-K96
Installing the Software

1.1 Installing the Software

Working with the R&S FS-K96 requires the installation of the software itself and the installation of several software components.
The best way to install the software and the required components is to use the browser tool that is delivered with the software.
If you install the software from a CD-ROM, systems that support the "AutoRun" func­tionality of the MS Windows operating system, automatically start the browser. If the system does not support the "AutoRun" feature or if you install the software from the download package available on the internet, you have to start the browser manually.
.NET Framework
.NET Framework 2.0 or higher is required to run both the browser tool and the soft­ware.
If opening the browser tool results in an error message, install the .NET Framework. The .NET Framework installer is available on the R&S FS-K96 CD-ROM. It is also part of the download package available on the R&S FS-K96 product homepage.
▶ Start the dotnetfx.exe and follow the instructions of the installer.
► Start the "AutoRun.exe".
The R&S FS-K96 opens the browser tool. The browser tool provides several tabs. Each one contains different information about the software (see number 2 to 5 in the picture below).
► Navigate to the "Installation" tab.
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Welcome to R&S FS-K96
Installing the Software
1 = Navigation and address bar 2 = Safety Instructions tab 3 = Software Installation tab 4 = Documentation tab 5 = Contact tab 6 = Tab menu 7 = Main window
The "Installation" tab has three categories in the tab menu:
●
Required Components Contains a guide to install the software components that are necessary to run the software.
●
Software Installation Contains a guide to install the R&S FS-K96 itself.
●
Release Notes Contains the release notes that were issued with each software release.

1.1.1 Installing Required Components

You have to install several software components required to successfully run the soft­ware. All components are delivered with the R&S FS-K96.
Required components
●
Microsoft .NET Framework 2.0
●
Microsoft Visual C++ Runtime Library (a specific version delivered with the R&S FS-K96)
●
MATLAB Component Runtime
●
Intel IPP Library
●
VISA
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► Navigate to the "Required Components" category in the "Installation" tab.
1 = Check for .NET Framework installation 2 = Install .NET Framework 3 = Install other required components (MATLAB etc.) 4 = Install VISA
Installing software components
Welcome to R&S FS-K96
Installing the Software
1. Click on the "R&S Framework Installer" link in the main window of the browser tool.
The browser tool opens a dialog box that contains an overview of the required components. It also shows if you have to install them or not.
2. In the "Installation State" column, check if the corresponding software is already installed.
● Ready to install
The software is installed after you have selected it in the "Install?" column.
● Ready to download
The R&S Framework installer was not able to find the installation file for the corresponding software. You have to get the program somewhere (for example download it off the inter­net) and install it manually.
Note that all components except the "Port Mapper" are mandatory.
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Note that some installation routines may not confirm the installation by a message like 'Installation Finished'. Therefore it might be necessary to restart the framework installer and check again, if all components are installed.
Installing VISA
It is also necessary to install VISA (Virtual Instrument Software Architecture) to access instruments connected to the PC via IEEE or LAN bus.
It is recommended to use the National Instruments VISA driver. The National Instru­ment VISA driver CD is supplied together with the R&S FSPC. You can also visit http://
www.ni.com/visa to get the latest version for your operating system if you are licensed
to.
Welcome to R&S FS-K96
Installing the Software

1.1.2 Installing R&S FS-K96

After installing all required components, you can install the R&S FS-K96.
► Navigate to the "Software Installation" category in the "Installation" tab.
1
= Install the analysis software
► Click on the "install the R&S FS-K96" link in the main window of the browser tool.
The browser tool starts a program (OFDM Vector Signal Analysis Software Version <x.x>.exe) that installs the software on your system.
The installer performs the following actions:
●
Install the R&S FS-K96 software including an uninstall tool
●
Create a Windows Start Menu entry (Programs ⇨ R&S OFDM Vector Analysis Software)
●
Create a shortcut on the desktop (optional)
●
If necessary (the software will specifically ask you to), set the required environment variables.
► Start the software via the Windows "Start Menu" entry or the shortcut on the desk-
top.
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Checking the installation
After the installation is finished, you chan check if the functionality of the software is fully available.
You can perform this test without a license in "Demo Mode"
1. Start the software.
2. Press the "Demod Settings" softkey. The R&S FS-K96 opens the "Signal Description" tab of the "Demodulation Set­tings" dialog box.
3. Press the "..." button to select a configuration file.
Welcome to R&S FS-K96
Installing the Software
4. Select the file WimaxOfdm_DL_G1_16_16QAM.mat The file is in the \CONFIGURATIONS directory of the software program folder.
5. Press the "Run Sgl" key.
The R&S FS-K96 opens a dialog box to select a signal file.
6. Select the file WimaxOfdm_DL_G1_16_16QAM.iq.tar. The file is in the \SIGNALS directory of the software program folder.
If the installation was successful, the software should display a valid measurement result.
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Welcome to R&S FS-K96
Licensing the Software

1.1.3 Deinstalling R&S FS-K96

You can uninstall the software itself via the uninstall tool available in the Windows "Start Menu" folder or via "Add or Remove Software" in the Windows "Control Panel".
The Framework components have to be uninstalled manually via "Add or Remove Soft­ware" in the Windows "Control Panel".
Before uninstalling the components, make sure that no other software uses one of the components.
The following components and programs have been installed:
●
Microsoft .NET Framework 2.0
●
Microsoft Visual C++ 2005 Redistributable
●
Matlab Component Runtime 7.11
●
Intel Integrated Performance Primitives RTI4.1
●
R&S Port Mapper
●
Rohde & Schwarz OFDM Vector Signal Analysis (R&S FS-K96)

1.2 Licensing the Software

The software provides the following general functionality.
●
To capture and analyze I/Q data from an R&S®FSW, R&S®FSV, R&S®FSVR, R&S®FSQ, R&S®FSG, R&S®FSUP or R&S®RTO.
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●
To read and analyze I/Q data from a file.
License type
The R&S FS-K96 allows you to capture and analyze I/Q data from one of the instru­ments listed above or read and anaylze I/Q data from a file.
You can purchase several different license types for the software.
●
R&S®FS-K96PC This license enables software operation with and without an R&S instrument. It is, for example, possible to read data from file without a connection to an instrument.
●
R&S®FS-K96 This license requires a connection to an R&S®FSV, R&S®FSVR, R&S®FSQ, R&S®FSG, R&S®FSUP, R&S®FSW or R&S®RTO. No license has to be installed on the instrument. A smartcard reader that contains the license (dongle) has to be connected to the PC.
●
R&S®FS-K196 This license is an upgrade for the R&S®FS-K96 / R&S®FS-K96PC that adds func­tionality for measurements on waveforms other than OFDM. It enables software operation with and without an R&S instrument. It is, for example, possible to read data from file without a connection to an instrument.
Welcome to R&S FS-K96
Licensing the Software
Demo mode
Basically, you can use the software in demo mode if you have no license. The demo mode has limited functionality, but you can analyze the I/Q data from sample files that are delivered with the software.
If no dongle with a valid license is found, the software shows a dialog that asks you to insert a smartcard with a valid license. Select the "Demo Mode" option to start the demo mode. The sample signals are delivered with the software and are installed in a subfolder of the software program folder.
%Application path%/SIGNALS/
Using the smartcard reader (dongle)
Before you can use the software, you have to load the license(s) on a smartcard (if you already have one) or order a new smartcard (R&S FSPC). New license types are avail­able as registered licenses (see below).
Note that you can upgrade the license from R&S FS-K96 to R&S FS-K96PC by order­ing the license type R&S FS-K96U.
You can use the smart card together with the USB smart card reader (for SIM format) supplied with the software. Alternatively, you can insert the smart card (full format) in a reader that is connected to or built into your PC.
Note that support for problems with the smart card licensing can only be guaranteed if the supplied USB smart card reader (for SIM format) is used.
1. With the delivery of the R&S FSPC you got a smart card and a smart card reader.
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2. Remove the smart card.
3. Insert the smart card into the reader. If the OMNIKEY label faces upward, the smart card has to be inserted with the chip facedown and the angled corner facing away from the reader.
Welcome to R&S FS-K96
Licensing the Software
4. After pushing the smart card completely inside the USB smart card reader, you can use it together with the software.
When you insert the USB Smartcard reader into the PC, the drivers will be loaded. If your PC does not already have drivers installed for this reader, the hardware will not be detected and the software will not work.
In this case, install the required driver manually. On the CD, it is in the folder \Install\USB SmartCard Reader Driver Files, named according to the pro­cessor architecture (OMNIKEY3x21_x86... or OMNIKEY3x21_x64). Detailed informa­tion on the file content and the download location for updated drivers can be found in the ReadMe.txt file in the same folder.
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You may have problems locking a computer while the card is inserted, because MS Windows tries to get log-in information from the card immediately after you have locked the computer.
Solve this issue by changing a registry entry.
Either execute the registry file DisableCAD.reg in the same folder the USM Smartcard reader installation files are located. Or manually change the entry.
●
Open the Windows Start Menu and select the "Run" item.
●
Enter "regedit" in the dialog to open the system reigistry.
●
Navigate to
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\ policies\system.
●
Set the value of DisableCAD to 0.
Note that security policies may prevent you from editing the value. Contact your IT administrator if you have problems with editing the value or installing the drivers.
Ordering licenses
Welcome to R&S FS-K96
Licensing the Software
New license types, such as the R&S FS-K96U that upgrades the R&S FS-K96 to the R&S FS-K96PC, can be ordered as registered license. This means that the license key code is based on the unique serial number of the R&S FSPC smartcard serial number.
1. Start the software (without a connected dongle). The software opens a dialog box that contains information about a licensing error.
2. Connect the smartcard / dongle to the computer.
The software opens the "Rohde & Schwarz License Information" dialog box.
3. Press the "Check Licenses" button.
The software shows all current licenses. The serial number which is necessary to know if you need a license is shown in the "Serial" column. The "Device ID" also contains the serial number.
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1.
2.
3.
4.
5. 6.
4. To enter a new license code, press the "Enter License Key Code" button.
Welcome to R&S FS-K96
Starting the Software

1.3 Starting the Software

► Start the software with the desktop icon or select "Programs" ⇨ "R&S OFDM Vec-
tor Signal Analysis Software" in the Windows Start menu.
The R&S FS-K96 checks if all required components are installed on your com­puter. After that, the actual GUI opens.
Software user interface
The user interface of the R&S FS-K96 in its default state looks like this:
Figure 1-1: Six Main Elements of the R&S FS-K96 Software
1 = Header table. The header table shows basic information like measurement frequency or capture length. 2 = Diagram. The diagram contains the measurement results. You can display the results in one or two win-
dows or screens. Each window contains a header and the actual diagram area. The header shows infor­mation about the measurement displayed in that window. The diagram area contains the measurement results.
3 = Status bar. The status bar contains information about the current status of the measurement and the
software. 4 = Hotkeys. Hotkeys contains functionality to control the measurement process. 5 = Softkeys. Softkeys contains functionality to configure and select measurement functions. 6 = Hardkeys. Hardkeys open new softkey menus.
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Display of measurement settings
The header table above the result displays shows information on hardware and mea­surement settings.
The header table contains the following information.
Configuration Name of the loaded configuration or 'Manual'.
Frequency The analyzer RF frequency.
Capture Length Capture length in number of samples and time.
Sampling Rate System sample rate.
FFT Length Length of the FFT interval in number of samples.
CP Length Length of Cyclic prefix interval in number of sam-
Welcome to R&S FS-K96
First Steps
ples.
Ref Level Reference level of the analyzer.
Trigger Mode Trigger condition of the analyzer.
Source Input source of the I/Q data.

1.4 First Steps

The "First Steps" contain a short measurement example to become familiar with the R&S FS-K96.
The following example uses a WLAN 802.11a signal to illustrate the functionality of the software. To perform the measurement, you need a signal generator, a spectrum or signal analyzer and a PC with the R&S FS-K96 installed on it.
The analyzer must be connected to the external PC via LAN or IEEE bus.

1.4.1 Setting up the Generator

This example requires an 802.11a or 802.11g-OFDM signal with 64QAM data modula­tion.
The Figure 1-2 shows the exemplary settings of an R&S SMU Vector signal generator.
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Welcome to R&S FS-K96
First Steps
Figure 1-2: WLAN Settings Menu of the R&S SMU Vector Signal Generator

1.4.2 Preparing the Measurement

1. Start the R&S FS-K96.
2. Press the PRESET key.
3. Press the SETUP key.
4. Select "Instrument" as the data source (➙"Data Source" softkey).
5. Press the "Configure Instrument Connection" to set up the instrument connection.
The R&S FS-K96 opens the "Instrument Connection" dialog box. For more information see Chapter 2.1, "Instrument Connection", on page 21.
6. Press the "Test Connection" button to test the connection.
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Welcome to R&S FS-K96
First Steps
1.4.2.1 General Setup
1. Press the "General Settings" softkey.
The R&S FS-K96 opens the "General Settings" dialog box.
2. Select the "Primary" tab.
3. Select "Spectrum Analyzer" as the instrument type.
4. Enter the required frequency to measure in the "Frequency" field.
5. Enter the 802.11a sample rate of 20 MHz in the "Sampling Rate" field.
6. Enter a capture length of 5 ms in the "Capture Time" field.
All other settings can remain as they are for this example.
1.4.2.2 Demodulation Setup
1. Press the "Demod Settings" softkey.
The R&S FS-K96 opens the "Demodulation Settings" dialog box.
2. Select the "Signal Description" tab.
3. Select "OFDM" as the "Analysis Mode".
4. Press the "..." button to load a configuration file.
The R&S FS-K96 opens a dialog box to select the configuration file.
5. Select and open the system configuration file WlanA_64QAM.mat.
6. Select the "Demodulation Control" tab.
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7. Define the "Result Length".
This sets the number of symbols per frame to the number of data symbols per OFDM burst plus 5 (4 preamble symbols + 1 signal field).
Welcome to R&S FS-K96
First Steps

1.4.3 Performing the Measurement

1. Press the "Run Sgl" hotkey to start the measurement.
After the R&S FS-K96 has finished the sweep, it shows the results of the measure­ment. By default, it shows the Capture Buffer result display and the Constellation Dia-
gram.
2. Press the "Display (Graph List)" softkey to show numerical results instead of the
graphical results.
Figure 1-3: Successful WLAN Measurement with the R&S
FS-K96
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2 General Configuration

The R&S FS-K96 allows you to configure global characteristics that are independent of measurements and do not have any effects on them.
● Instrument Connection............................................................................................21
● Software Configuration............................................................................................26
● Display Configuration..............................................................................................27
● Data Management...................................................................................................28
General Configuration
Instrument Connection

2.1 Instrument Connection

In order to be able to communicate with an analyzer (R&S FSQ, R&S FSUP, R&S FSG, R&S FSV, R&S FSVR or R&S FSW) or oscilloscope (R&S RTO family), you have to connect it to a computer. You can use the IEEE bus (GPIB) or a local area net­work (LAN).
FSQ/FSG/FSUP/FSV/FSVR/FSW requirement
Any
●
R&S FSQ as of firmware version 4.35
●
R&S FSG as of firmware version 4.39
●
R&S FSUP as of firmware version 4.37
●
R&S FSV as of firmware version 1.10
●
R&S FSVR as of firmware version 1.51
●
R&S FSW
●
R&S RTO as of firmware version 1.47.2.x
can be used.
● Instrument Connection Configuration......................................................................21
● Figuring Out IP Addresses......................................................................................23

2.1.1 Instrument Connection Configuration

The "Instrument Connection Configuration" dialog box contains functionality that is necessary to successfully establish a connection in a network of analyzers. The dialog box contains several elements.
1. Press SETUP key.
2. Select "Instrument" as the data source (➙"Data Source" softkey).
3. Press "Configure Instrument Connection".
The software opens the corresponding dialog to configure the connection.
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Interface Type
Selects the type of interface you want to use. You have to connect the analyzer or oscilloscope via LAN interface or the IEEE bus (GPIB).
Number
Selects the number of the interface if the PC has more than one interfaces (e.g. sev­eral LAN cards).
Address
General Configuration
Instrument Connection
Defines the address of the instrument. The type of content depends on the interface type.
●
GPIB Address Primary GPIB address of the analyzer. Possible values are in the range from 0 to
31. The default GPIB address for an R&S instruments is 20. Available for IEEE bus systems using the IEEE 488 protocol. The interface type is GPIB.
●
IP Address or Computer Name Name or host address (TCP/IP) of the computer. Available for LAN bus systems using either the VXI-11 protocol or a Rohde&Schwarz specific protocol (RSIB). The interface type is either LAN (VXI-11) or LAN (RSIB). Contact your local IT support for information on free IP addresses.
– The RSIB protocol is supported by all firmware version of the R&S analyzers
and oscilloscopes.
– The VXI-11 protocol is supported as of R&S FSQ firmware version 3.65 and by
all firmware version of the R&S FSV(R), R&S FSG and oscilloscopes.
●
Complete VISA Resource String Allows you to enter the complete VISA resource string manually. A VISA string is made up out of the elements mentioned above, separated by double colons (::), e.g. GPIB::20::INSTR. Available for interface type "Free Entry".
Subsystem
Shows the subsystem in use. Typically you do not have to change the subsystem.
VISA RSC
Shows or defines the complete VISA resource string.
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SCPI command:
CONFigure:ADDRess<analyzer> on page 130
Test Connection
Button that tests the connection.
If the connection has been established successfully, the software returns a PASSED message. If not, it shows a FAILED message.
General Configuration
Instrument Connection

2.1.2 Figuring Out IP Addresses

Each of the supported instruments logs its network connection information in a different place. Find instructions on how to find out the necessary information below.
2.1.2.1 Figuring Out the Address of an R&S FSQ or R&S FSG
Follow these steps to figure out GPIB or IP address of an R&S FSQ or R&S FSG.
Figuring Out the GPIB address
1. Press the SETUP key.
2. Press the "General Setup" softkey.
3. Press the "GPIB" softkey.
The R&S FSQ / FSG opens a dialog box that shows its current GPIB address.
Figuring Out the IP address
1. Press the SETUP key.
2. Press the "General Setup" softkey.
3. Press the "Configure Network" softkey.
4. Press the "Configure Network" softkey.
The MS Windows "Network Connections" dialog box opens.
5. Select the "Local Area Connection" item.
The "Local Area Connection Status" dialog box opens.
6. Select the "Support" tab.
The "Support" tab shows the current TCP/IP information of the R&S FSQ.
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General Configuration
Instrument Connection
2.1.2.2 Figuring Out the Address of an R&S FSV or R&S FSVR
Follow these steps to figure out the GPIB or IP address of an R&S FSV or R&S FSVR.
Figuring Out the GPIB address
1. Press the SETUP key.
2. Press the "General Setup" softkey.
3. Press the "GPIB" softkey.
4. Press the "GPIB Address" softkey.
The R&S FSV(R) opens a dialog box that shows its current GPIB address.
Figuring Out the IP address
1. Press the SETUP key.
2. Press the "General Setup" softkey.
3. Press the "Network Address" softkey.
4. Press the "IP Address" softkey.
The R&S FSV(R) opens a dialog box that contains information about the LAN con­nection.
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General Configuration
Instrument Connection
2.1.2.3 Figuring Out the Address of an R&S FSW
Follow these steps to figure out the GPIB or IP address of an R&S FSW.
Figuring Out the GPIB address
1. Press the SETUP key.
2. Press the "Network + Remote" softkey.
The R&S FSW opens the "Network & Remote" dialog box.
3. Select the "GPIB" tab.
The R&S FSW shows information about the GPIB connection, including the GPIB address.
Figuring Out the IP address
1. Press the SETUP key.
2. Press the "Network + Remote" softkey.
The R&S FSW opens the "Network & Remote" dialog box and shows its current IP address in the corresponding field.
2.1.2.4 Figuring Out the Address of an R&S RTO
Follow these steps to figure out the network address of an R&S RTO.
► Press the SETUP key.
The R&S RTO opens a dialog box that contains general information about the sys­tem.
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General Configuration
Software Configuration

2.2 Software Configuration

The "Setup" menu contains various general software functions.
► Press the SETUP key to access the "Setup" menu.
Configure Instrument Connection
Opens the "Instrument Connection Configuration" dialog box.
For more information see Chapter 2.1.1, "Instrument Connection Configuration", on page 21.
Remote command:
CONFigure:ADDRess<analyzer> on page 130
Data Source (Instr File)
Selects the general input source (an instrument or a file).
Remote Control Settings
Turns remote control support on and off.
Show Logging
Opens a dialog box that contains a log of all messages that the software has shown in the status bar.
Use the message log for debugging purposes in case any errors occur. You can refresh and clear the contents of the log or copy the contents of the system log to the clipboard.
"Refresh"
"Clear All"
"Copy to Clip-
Updates the contents of the log.
Deletes all entries in the log.
Copies the contents of the log to the clipboard.
board"
System Info
Opens a dialog box that contains information about the system like driver versions or the utility software. You can use this information in case an analyzer does not work properly.
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General Configuration
Display Configuration

2.3 Display Configuration

The "Display" menu contains functionality to improve the display and documentation of results.
► Press the DISP key.
The R&S FS-K96 opens the "Display" menu.
Full screen and split screen
The R&S FS-K96 provides two screen modes.
●
Split screen mode The user interface contains two measurement screens or windows labeled screen A (on the top) and screen B (on the bottom). In split screen mode, the software allows you to display two different measurement results.
●
Full screen mode The user interface contains one measurement screen or window. In full screen mode, you can display only one measurement result.
The scale of the horizontal axis is the same in both modes. The scale of the vertical axis is also the same, but the resolution is smaller in split screen mode.
► Press the "Full Screen" softkey or the "Split Screen" softkey.
When you change into full screen mode, the software increases the size of the active screen. The active screen has a label highlighted in green, for example .
► To switch from one screen to the other, use the "Screen A" and "Screen B" hot-
keys.
SCPI command:
DISPlay:FORMat on page 158
DISPlay[:WINDow<n>]:SELect on page 159
Separate window
With the "Open in Separate Window" function, you can create a copy of the currently selected screen and display it in a new window outside the main user interface.
Opening the results in a separate window allows you to display more than two results at the same time.
Background color
The background color of the software by default is black. Apply another color via the "Background Color" softkey and the corresponding dialog box.
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Hardcopy
For documentation purposes the software provides a hardcopy function that lets you save the current results in one of the following formats.
●
bmp
●
gif
●
jpeg
●
png
●
tiff
Use the "Hardcopy to Clipboard" function to take a screenshot.
SCPI command:
MMEMory:NAME on page 159
HCOPy[:IMMediate] on page 159
General Configuration
Data Management

2.4 Data Management

The R&S FS-K96 allows you to import and export various types of data to and from a file.
The necessary functionality is part of the "File" menu.
● Settings................................................................................................................... 28
● I/Q Data...................................................................................................................29
● Demodulation Data................................................................................................. 31
● Limits.......................................................................................................................32

2.4.1 Settings

The R&S FS-K96 allows you to save the current measurement settings. Saving set­tings is an easy way to use the same configuration again at a later time.
Exporting settings
1. Press the FILE key.
2. Press the "Save Settings" softkey.
The R&S FS-K96 opens a dialog box to define the file name.
SCPI command:
MMEMory:STORe:STATe on page 158
Restoring settings
1. Press the FILE key.
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2. Press the "Recall Settings" softkey.
The R&S FS-K96 opens a dialog box to select a configuration file.
3. Alternatively, drag and drop a file on the software user interface.
SCPI command:
MMEMory:LOAD:STATe on page 157
The file format for settings is .ovsa.
General Configuration
Data Management

2.4.2 I/Q Data

In addition to capturing I/Q data directly from an Rohde & Schwarz instrument, the R&S FS-K96 allows you to analyze I/Q data from a file that contains such data. The software also provides functionality to store I/Q data you have captured with an instru­ment in a file for further analysis at a later time (for example with external tools).
The R&S FS-K96 supports several file formats for the I/Q data. In all cases the data is linearly scaled using the unit Volt (if a correct display of e.g. Capture Buffer power is required).
Exporting data
1. Press the FILE key.
2. Press the "Save I/Q Data" softkey.
The R&S FS-K96 opens a dialog box to define the file name and data type.
SCPI command:
MMEMory:STORe:IQ:STATe on page 158
Importing data
1. Press the SETUP key.
2. Select "File" as the data source (➙ "Data Source (Instr File)" softkey).
"File" is selected when it is highlighted green.
3. Press the "Run Sgl" softkey.
The R&S FS-K96 opens a dialog box to select a file.
4. Alternatively, drag and drop a file on the software user interface.
Note that the software displays an error message if the file containing I/Q data could not be found or is not valid.
SCPI command:
MMEMory:LOAD:IQ:STATe on page 157
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Format: *.dat (binary)
Binary data in the .dat format is expected as 32-bit floating point data, Little Endian for­mat (also known as LSB Order or Intel format). The order of the data is either
IQIQIQ...
or
III...IQQQ...Q
Example: 0x1D86E7BB in hexadecimal notation will be decoded to -7.0655481E-3
Format *.iqw (ASCII)
ASCII data in the .iqw format is expected as I and Q values in one of the following orders.
IQIQIQ...
or
III...IQQQ...Q
General Configuration
Data Management
Format *.wv
The waveform format (.wv) is based on encrypted data.
The format complies with the waveform format that is used by the R&S Signal Genera­tors and R&S®WinIQSIM Software, for example.
Format *.iq.tar (binary)
An .iq.tar file contains I/Q data in binary format together with meta information that describes the nature and the source of data, for example the sample rate. The objec­tive of the .iq.tar file format is to separate I/Q data from the meta information while still having both inside one file. In addition, the file format allows you to include customized data.
An .iq.tar file must contain the following files.
●
I/Q parameter .xml file Contains meta information about the I/Q data (e.g. sample rate). The filename can be defined freely, but there must be only one single I/Q parameter .xml file inside an .iq.tar file.
●
I/Q data binary file Contains the binary I/Q data of all channels. There must be only one single I/Q data binary file inside an .iq.tar file.
Optionally, an .iq.tar file can contain the following file.
●
I/Q preview .xslt file Contains a stylesheet to display the I/Q parameter .xml file and a preview of the I/Q data in a web browser.
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General Configuration
Data Management

2.4.3 Demodulation Data

The R&S FS-K96 allows you to save the demodulated data for further evaluation in Matlab. The demodulated data is collected at the end of the signal chain and is stored in a time frequency matrix representing the analyzed OFDM frames.
Exporting data
1. Press the FILE key.
2. Press the "Save Demod Data" softkey.
SCPI command:
MMEMory:STORe:DEMod:STATe on page 157
If you have described the signal with the "Configuration File Wizard", proceed as fol­lows to export the demodulation data.
The demodulation data can also be read out via remote control commands. The demodulated symbols and the reference symbols are available as traces 3 and 4 of the constellation diagram. This allows a seamless integration of the R&S FS-K96 within larger OFDM software projects.
The demodulation data is stored in a MATLAB file (.mat).
This file contains two matrices named 'mfcRlk' and 'mfcAlk'.
●
The matrix 'mfcRlk' contains the demodulated and corrected OFDM symbols.
●
The matrix 'mfcAlk' contains the associated reference symbols.
The size of the matrix is 'Number of Symbols' x 'FFT Length'.
The following example code shows how to load the demodulation data in Matlab and plot the constellation diagram:
% load file
s = load('mydata.mat', '-mat');
% show constellation
plot(real(s.mfcRlk), imag(s.mfcRlk), 'bo');
hold on;
plot(real(s.mfcAlk), imag(s.mfcAlk), 'rx');
hold off;
Exporting Wizard data
1. Press the FILE key.
2. Press the "Export Wizard Data" softkey.
The R&S FS-K96 opens a dialog box to define the file name.
For more information on the Wizard see Chapter 5.2.1, "Overview of the R&S FS-K96
Configuration File Wizard", on page 86.
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General Configuration
Data Management

2.4.4 Limits

The R&S FS-K96 allows you to use custom limit definition instead of the predefined limits provided with the software. Limits are used in the Result Summary.
Importing data
► Copy the limit definition file (limits.xml) to
"%Program folder%\Rohde-Schwarz\ OFDM Vector Signal Analysis Software".
Note that the file name must be limits.xml. The R&S FS-K96 automatically imports the new limit definitions and applies them.
The file format for limit definitions is .xml. The structure of the file is as follows.
<Limits>
<EVMAll/><!--Unit: dB-->
<EVMData/><!--Unit: dB-->
<EVMPilot/><!--Unit: dB-->
<IQOffset/><!--Unit: dB-->
<IQGainImbalance/><!--Unit: dB-->
<IQQuadratureError/><!--Unit: deg-->
<FrequencyError/><!--Unit: Hz-->
<SampleClockError/><!--Unit: ppm-->
<FramePower/><!--Unit: dBm-->
<CrestFactor/><!--Unit: dB-->
</Limits>
<!--Example
<Limits>
<EVMAll Mean="-40" Max="-30"/>
</Limits>
-->
Limit definitions which are not required may be skipped by making no entries or by deleting the complete tag.
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3 Measurements and Result Displays

The OFDM Vector Signal Analysis software features several measurements to exam­ine and analyze different aspects of a signal.
The source of the data that is processed is either a live signal or a previously recorded signal whose characteristics have been saved to a file. For more information see "Selecting the Input Source".
In both cases, you can perform a continuous or a single measurement.
Continuous measurements capture and analyze the signal continuously and stop only after you turn it off manually.
► Press the "Run Cont" softkey to start and stop continuous measurements.
Single measurements capture and analyze the signal over a particular time span or number of frames. The measurement stops after the time has passed or the frames have been captured.
Measurements and Result Displays
Numerical results
► Press the "Run Sgl" softkey to start a single measurement.
You can also repeat a measurement based on the data that has already been cap­tured, e.g. if you want to apply different demodulation settings to the same signal.
► Press the "Refresh" softkey to measure the signal again.
This chapter provides information on all types of measurements that the OFDM Vector Signal Analysis software supports.
While the measurement is running, certain events may cause it to fail. A corresponding error message is displayed in the status bar and stored in the error log.
SCPI command:
INITiate[:IMMediate] on page 118
INITiate:REFResh on page 119
● Numerical results.................................................................................................... 33
● Graphical Results....................................................................................................34
● I/Q Measurements...................................................................................................36
● Result Summary......................................................................................................49

3.1 Numerical results

The R&S FS-K96 features the following numerical results.
EVM measurements
●
"EVM All"
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Shows the EVM for all data and all pilot cells of the analyzed frame.
●
"EVM Data" Shows the EVM for all data cells of the analyzed frame.
●
"EVM Pilot" Shows the EVM for all pilot cells of the analyzed frame.
●
"MER All" Shows the Modulation Error Ratio (MER) for all data and all pilot cells of the ana­lyzed frame. The MER is the ratio of the RMS power of the ideal reference signal to the RMS power of the error vector.
I/Q constellation measurements
●
"I/Q Offset" Shows the power at spectral line 0 normalized to the total transmitted power.
●
"Gain Imbalance" Shows the logarithm of the 'Q-Channel to I-Channel gain ratio'.
●
"Quadrature Error" Shows the measure of the 'phase angle between Q-Channel and I-Channel' deviat­ing from the ideal 90 degrees.
Measurements and Result Displays
Graphical Results
Frequency measurements
●
"Frequency Error" Shows the difference between measured and reference center frequency.
●
"Sample Clock Error" Shows the difference between measured and reference sample clock relative to the system sampling rate.
Power measurements
●
"Frame Power" Shows the average time domain power of the analyzed frame.
●
"Crest Factor" Shows the peak-to-average power ratio of the analyzed frame.

3.2 Graphical Results

The R&S FS-K96 provides the following graphical result displays.
Power measurements
●
"Power vs. Symbol X Carrier" Evaluates the power profile of all cells in the analyzed frame.
●
"Power vs. Carrier" Evaluates the power of all carriers in the analyzed frame averaged over the sym­bols.
●
"Power vs. Symbol"
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Evaluates the power of all symbols in the analyzed frame averaged over the carri­ers.
●
"Capture Buffer" Evaluates the power profile of the capture buffer data being analyzed.
●
"Power Spectrum" Evaluates the power density spectrum of the complete capture buffer.
EVM measurements
●
"EVM vs. Symbol X Carrier" Evaluates the EVM of all cells in the analyzed frame.
●
"EVM vs. Carrier" Evaluates the EVM of all carriers in the analyzed frame averaged over the sym­bols.
●
"EVM vs. Symbol" Evaluates the EVM of all symbols in the analyzed frame averaged over the carri­ers.
●
"Error Freq / Phase" Evaluates the frequency and phase error vs. time for the samples.
Measurements and Result Displays
Graphical Results
Channel measurements
●
"Flatness" Evaluates the magnitude of the channel transfer function.
●
"Group Delay" Evaluates the relative group delay of the transmission channel.
●
"Impulse Response" Evaluates the magnitude of the channel impulse response and position within the guard interval.
Constellation measurements
●
"Constellation Diagram" Shows the complex constellation diagram of the modulation symbols. Different cell types are mapped to different colors. The contents depend on the symbols you have selected to be displayed ("Constellation Selection").
●
"Constellation vs. Carrier" Shows the real and imaginary part of the modulation symbols over all carriers.
●
"Constellation vs. Symbol" Shows the real and imaginary part of the modulation symbols over all symbols.
Miscellaneous and statistics
●
"CCDF" Evaluates the complementary cumulative probability distribution for the capture buffer samples relative to the average power.
●
"Signal Flow" Shows a detailed description of the current measurement status.
●
"Report"
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Shows a detailed list of the demodulation steps.
●
"Allocation Matrix" Shows a graphical representation of the allocation matrix (i.e. structure matrix) defined in the configuration file.
Measurements and Result Displays
I/Q Measurements

3.3 I/Q Measurements

This section contains a detailed description of the measurements.
● Power Measurements............................................................................................. 36
● EVM Measurements................................................................................................39
● Channel Measurements..........................................................................................43
● Constellation Measurements...................................................................................44
● Statistics and Miscellaneous Measurements.......................................................... 46

3.3.1 Power Measurements

Power vs Symbol x Carrier............................................................................................36
Power vs Carrier........................................................................................................... 37
Power vs Symbol.......................................................................................................... 37
Capture Buffer...............................................................................................................38
Power Spectrum............................................................................................................39
Power Selection............................................................................................................ 39
Power vs Symbol x Carrier
The Power vs Symbol x Carrier display shows the power of each carrier in each sym­bol of the received signal frames in dBm. The resolution bandwidth of the measure­ment filter is the carrier spacing.
●
Press the "Power" softkey.
●
Press the "Power vs Sym x Carrier" softkey.
Figure 3-1: Power vs. Symbol x Carrier Display
The power is measured with a resolution bandwidth that equals the carrier spacing.
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The power levels are represented by colors. The corresponding color map is displayed at the top of the result display.
All analyzed frames are concatenated in symbol direction.
Remote command:
CALC:FEED 'POW:PVSC' TRACe:DATA
Power vs Carrier
The Power vs. Carrier display shows the power of each carrier of the received signal frames in dBm with statistics in symbol direction.
●
Press the "Power" softkey.
●
Press the "Power vs Carrier" softkey.
Measurements and Result Displays
I/Q Measurements
Figure 3-2: Power vs Carrier Display
The power is measured with a resolution bandwidth that equals the carrier spacing.
You can display the power vs carrier for a particular symbol with Power Selection.
Remote command:
CALC:FEED 'POW:PVCA' TRACe:DATA
Power vs Symbol
The Power vs Symbol display shows the power of each symbol of the received signal frames in dBm with statistics in carrier direction.
●
Press the "Power" softkey.
●
Press the "Power vs Symbol" softkey.
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Figure 3-3: Power vs Symbol Display
The power is measured with a resolution bandwidth that equals the carrier spacing.
All analyzed frames are concatenated in symbol direction with blue lines marking the frame borders. Carriers which contain 'Zero'-cells over the complete symbol range (e.g. guard carriers or DC carrier) are excluded from the statistic.
You can display the power vs symbol for a particular carrier with Power Selection.
Remote command:
CALC:FEED 'POW:PVSY' TRACe:DATA
Measurements and Result Displays
I/Q Measurements
Capture Buffer
The capture buffer shows the complete range of captured data for the last sweep. The Capture Buffer display shows the power of the captured I/Q data versus time in dBm. The analyzed frames are identified with a green bar at the bottom of the Capture Buffer display.
●
Press the "Power" softkey.
●
Press the "Capture Buffer" softkey.
Figure 3-4: Capture Buffer Display
All I/Q measurements process the same signal data. Therefore, all I/Q measurement results are available after a single I/Q measurement has been executed. I/Q measure­ments may be performed for RF or baseband input.
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Remote command:
CALC:FEED 'POW:CBUF' TRACe:DATA
Power Spectrum
The Power Spectrum display shows the power density spectrum of the complete cap­ture buffer in dBm/Hz.
●
Press the "Power" softkey.
●
Press the "Power Spectrum" softkey.
Measurements and Result Displays
I/Q Measurements
Figure 3-5: Power Spectrum Display
Remote command:
CALC:FEED 'POW:PSPE' TRACe:DATA
Power Selection
Opens a dialog box to filter the results that are displayed in the "Power vs Symbol" and "Power vs Carrier" result displays.
Figure 3-6: Power Evaluation Filter panel
Note that if you use several screens, it is not possible to have two different filters for the different screens.

3.3.2 EVM Measurements

EVM vs Symbol x Carrier.............................................................................................. 40
EVM vs Carrier..............................................................................................................40
EVM vs Symbol.............................................................................................................41
Error Freq / Phase.........................................................................................................41
EVM Selection...............................................................................................................42
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EVM vs Symbol x Carrier
The EVM vs Symbol x Carrier display shows the EVM of each carrier in each symbol of the received signal frames in dB or %, depending on the unit settings.
●
Press the "EVM" softkey.
●
Press the "EVM vs Sym x Carrier" softkey.
Figure 3-7: EVM vs Symbol x Carrier Display
Measurements and Result Displays
I/Q Measurements
The EVM values are represented by colors. The corresponding color map is displayed at the top of the result display.
All analyzed frames are concatenated in symbol direction.
Remote command:
CALC:FEED 'EVM:EVSC' TRACe:DATA
EVM vs Carrier
The EVM vs Carrier display shows the EVM of each carrier of the received signal frames in dB or %, depending on the unit settings, with statistics in symbol direction.
●
Press the "EVM" softkey.
●
Press the "EVM vs Carrier" softkey.
Figure 3-8: EVM vs Carrier Display
You can display the EVM vs carrier for a particular symbol with the "EVM Selection" function.
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Remote command:
CALC:FEED 'EVM:EVCA' TRACe:DATA
EVM vs Symbol
The EVM vs. Symbol display shows the EVM of each symbol of the received signal frames in dB or %, depending on the unit settings, with statistics in carrier direction. All analyzed frames are concatenated in symbol direction with blue lines marking the frame borders. Carriers which contain 'Zero'-cells over the complete symbol range (e.g. guard carriers or DC carrier) are excluded from the statistic.
●
Press the "EVM" softkey.
●
Press the "EVM vs Symbol" softkey.
Measurements and Result Displays
I/Q Measurements
Figure 3-9: EVM vs Symbol Display
You can display the EVM vs symbol for a particular carrier with the "EVM Selection" function.
Remote command:
CALC:FEED 'EVM:EVSY' TRACe:DATA
Error Freq / Phase
The Error Frequency display shows the frequency deviations in Hz versus time. The Error Phase display shows the phase deviations in Degree versus time. The evaluation length of this measurement can be set in the measurement setup menu (see Chap-
ter 4.1.3, "Measurement Settings", on page 60).
●
Press the "EVM" softkey.
●
Press the "Error Freq Phase" softkey. Repeated pressing of the softkey toggles between Frequency and Phase Error.
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Figure 3-10: Frequency Error
Measurements and Result Displays
I/Q Measurements
Figure 3-11: Phase Error
All analyzed frames are concatenated in time direction with blue lines marking the frame borders.
Remote command:
CALC:FEED 'EVM:FERR' CALC:FEED 'EVM:PERR' TRACe:DATA
EVM Selection
Opens a dialog box to filter the results that are displayed in the "EVM vs Symbol" and "EVM vs Carrier" result displays.
Figure 3-12: EVM Evaluation Filter panel
Note that if you use several screens, it is not possible to have two different filters for the different screens.
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Measurements and Result Displays
I/Q Measurements

3.3.3 Channel Measurements

Channel Flatness.......................................................................................................... 43
Group Delay.................................................................................................................. 43
Channel Impulse Response.......................................................................................... 44
Channel Flatness
The Channel Flatness display shows the amplitude of the channel transfer function vs. carrier. The statistic is performed over all analyzed frames.
●
Press the "Channel" softkey.
●
Press the "Flatness" softkey.
Figure 3-13: Channel Flatness Display
Remote command:
CALC:FEED 'CHAN:FLAT' TRACe:DATA
Group Delay
The Group Delay display shows the relative group delay of the transmission channel. The statistic is performed over all analyzed frames.
●
Press the "Channel" softkey.
●
Press the "Group Delay" softkey.
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Remote command:
CALC:FEED 'CHAN:GDEL' TRACe:DATA
Channel Impulse Response
The Channel Impulse Response display shows the impulse response of the channel and its position within the guard interval. The start and the end of the guard interval are marked with blue lines. The statistic is performed over all analyzed frames.
●
Press the "Channel" softkey.
●
Press the "Impulse Response" softkey.
Measurements and Result Displays
I/Q Measurements
Figure 3-14: Channel Impulse Response Display
Remote command:
CALC:FEED 'CHAN:IRES' TRACe:DATA

3.3.4 Constellation Measurements

Constellation Diagram...................................................................................................44
Constellation vs Carrier.................................................................................................45
Constellation vs Symbol................................................................................................45
Constellation Selection..................................................................................................46
Constellation Diagram
The Constellation Diagram display shows the inphase and quadrature results over the full range of the measured input data. The ideal points for the selected cell types are displayed for reference purposes.
●
Press the "Constell" softkey.
●
In the submenu, press the "Constell" softkey.
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Figure 3-15: Constellation Diagram Display
Remote command:
CALC:FEED 'CONS:CONS' TRACe:DATA
Measurements and Result Displays
I/Q Measurements
Constellation vs Carrier
The Constellation vs. Carrier display shows the inphase and quadrature magnitude results of all symbols over the respective carriers. The inphase-values are displayed as yellow dots; the quadrature-values are displayed as blue dots.
●
Press the "Constell" softkey.
●
Press the "Constell vs Carrier" softkey.
Figure 3-16: Constellation vs. Carrier Display
Remote command:
CALC:FEED 'CONS:CVCA'
Constellation vs Symbol
The Constellation vs. Symbol display shows the inphase and quadrature magnitude results of all carriers over the respective symbols. The inphase-values are displayed as yellow dots; the quadrature-values are displayed as blue dots. All analyzed frames are concatenated in symbol direction with blue lines marking the frame borders.
●
Press the "Constell" softkey.
●
Press the "Constell vs Symbol" softkey.
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Figure 3-17: Constellation vs. Symbol Display
Remote command:
CALC:FEED 'CONS:CVSY'
Constellation Selection
Opens a dialog box to filter the results that are displayed in the constellation diagrams.
Measurements and Result Displays
I/Q Measurements
Figure 3-18: Constellation Evaluation Filter Panel
The results may be filtered by any combination of cell type, modulation, symbol, or car­rier. The results are updated as soon as any change to the constellation selection parameters is made.
Note that if you use several screen and have the constellation display on each of these screens, it is not possible to have two different filters for the different screens.

3.3.5 Statistics and Miscellaneous Measurements

CCDF............................................................................................................................ 46
Signal Flow....................................................................................................................47
Demodulation Report.................................................................................................... 48
Allocation Matrix............................................................................................................48
CCDF
The CCDF results display shows the probability of an amplitude exceeding the mean power. The X axis displays power relative to the measured mean power.
●
Press the "Misc / Statistic" softkey.
●
Press the "CCDF" softkey.
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Figure 3-19: CCDF Display
Remote command:
CALC:FEED 'STAT:CCDF' TRACe:DATA
Measurements and Result Displays
I/Q Measurements
Signal Flow
The Signal Flow display shows a detailed description of the current measurement sta­tus. It provides additional hints on what is going wrong within the signal analysis. Unused blocks are crossed out.
●
Press the "Misc / Statistic" softkey.
●
Press the "Signal Flow" softkey.
Figure 3-20: Signal Flow Display
For the synchronization blocks, a bar is shown giving information about the reliability of the synchronization result. If the level in the bar falls below the thresholds indicated by the horizontal line, the color of the bar changes from green to yellow and finally to red. When the synchronization of the block fails, the complete block changes its color and all succeeding arrows change their color too.
For detailed information about the complete synchronization process, refer to section
7.2.2.
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Remote command:
CALC:FEED 'STAT:SFLO'
Demodulation Report
The demodulation report lists messages generated by the signal processing kernel. It can give additional hints about the signal processing chain.
●
Press the "Misc / Statistic" softkey.
●
Press the "Report" softkey.
Measurements and Result Displays
I/Q Measurements
Figure 3-21: Demodulation Report
Remote command: not supported
Allocation Matrix
The Allocation Matrix display is a graphical representation of the allocation matrix (i.e. structure matrix) defined in the configuration file. It is possible to use the marker in order to get more detailed information on the individual cells.
●
Press the "Misc / Statistic" softkey.
●
Press the "Allocation Matrix" softkey.
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Figure 3-22: Allocation Matrix
Remote command: not supported
Measurements and Result Displays
Result Summary

3.4 Result Summary

The Result Summary table is displayed for I/Q measurements when the display mode is set to LIST. This table shows the overall scalar measurement results. The statistic is performed over all analyzed frames within the capture buffer.
Figure 3-23: Result Summary Display
The Result Summary display is selected by pressing the "DISPLAY – LIST" softkey, which is available in all main measurement menus and submenus.
SCPI command:
see Chapter 7.4.4, "Numerical Results", on page 126
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4 Settings

This section describes the "General Settings" dialog box, where all settings related to the overall measurement (i.e. "Data Capture Settings", "Input, Level", "Trigger", "Input Settings") can be modified.
Settings
General Settings

4.1 General Settings

This section describes the "General Settings" panel, where all settings related to the overall measurement (i.e. Data Capture, Trigger and Input settings) can be modified.
The "General Settings" softkey opens the "General Settings" dialog box with three tabs: "Primary", "Advanced" and "Meas". To see the content of the tabs as shown below click on one of the tabs.
Figure 4-1: Tabs in General Settings Dialog
For a detailed description of the primary, advanced and measurement settings see below.
● Primary Settings......................................................................................................50
● Advanced Settings.................................................................................................. 56
● Measurement Settings............................................................................................ 60

4.1.1 Primary Settings

The "Primary Settings" contain general settings to configure the measurement.
The "Primary Settings" tab is part of the "General Settings" dialog box.
● Instrument Settings................................................................................................. 50
● Data Capture Settings.............................................................................................51
● Level Settings..........................................................................................................52
● Trigger Settings.......................................................................................................53
● Input Settings.......................................................................................................... 54
4.1.1.1 Instrument Settings
The "Instrument Settings" contain settings that define the type of instrument you are using.
The "Instrument Settings" are part of the "Primary" tab of the "General Settings" dialog box.
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Instrument Type............................................................................................................ 51
RTO Input Channel....................................................................................................... 51
Instrument Type
Selects the type of instrument you are using to analyze the I/Q data.
You can use a spectrum analyzer or oscilloscope. For more information on supported instruments see Chapter 2.1, "Instrument Connection", on page 21.
Remote command:
CONFigure:INSTrument:TYPE on page 130
RTO Input Channel
Selects the input channel you have applied the signal to.
Input channel selection is avilable for measurements with an oscilloscope.
Remote command:
CONFigure:RTO:CHANnel on page 131
Settings
General Settings
4.1.1.2 Data Capture Settings
The "Data Capture Settings" contain settings that describe the physical attributes of the signal to be measured.
The "Data Capture Settings" are part of the "Primary" tab of the "General Settings" dia­log box.
Frequency..................................................................................................................... 51
Sampling Rate...............................................................................................................51
Capture Time................................................................................................................ 52
Frequency
Defines the frequency of the signal you are about to measure.
The frequency range depends on the instrument you are using.
Remote command:
[SENSe:]FREQuency:CENTer on page 131
Sampling Rate
Defines the system sampling rate of the signal you are about to measure.
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The sampling rate range depends on the instrument you are using.
Remote command:
TRACe:IQ:SRATe on page 132
Capture Time
Defines the amount of data that is captured with one sweep and stored in the capture buffer.
The capture time range depends on the instrument you are using.
Remote command:
[SENSe:]SWEep:TIME on page 131
Settings
General Settings
4.1.1.3 Level Settings
The "Level Settings" contain general settings to define the power leveling of the R&S analyzer.
The "Level Settings" are part of the "Primary" tab of the "General Settings" dialog box.
Auto Level..................................................................................................................... 52
Reference Level / Signal Peak Level............................................................................ 52
External Attenuation......................................................................................................53
Auto Level
Turns automatic determination of the reference level or signal peak level on and off.
If on, the R&S FS-K96 performs a measurement to determine the ideal level for the signal currently applied. This measurement is performed prior to each actual measure­ment. Note that the auto level measurements results in slightly increased measure­ment time.
The length of the measurement is determined by the Auto Level Track Time.
Automatic levelling is available for RF measurements with a spectrum analyzer and measurements with oscilloscopes.
Remote command:
CONFigure:POWer:AUTO on page 132
Reference Level / Signal Peak Level
Defines the reference level (for RF measurements with a spectrum analyzer) or signal peak level (for measurements with an oscilloscope or analog baseband) for the mea­surement.
You can define the level manually when you turn Auto Level off. If the "Auto Level" function is on, the R&S FS-K96 shows the level it has determined.
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Note that the unit depends on the type of instrument and input source you are using. For spectrum and signal analyzers, the unit of the reference level is dBm. For oscillo­scopes and analog baseband input, the unit is V.
Remote command: Spectrum analyzer reference level (RF input):
DISPlay[:WINDow<n>]:TRACe<t>:Y[:SCALe]:RLEVel[:RF] on page 132
Analog baseband input:
[SENSe:]VOLTage:IQ:RANGe on page 133
Oscilloscope signal peak level:
[SENSe:]VOLTage:RTO:RANGe on page 133
External Attenuation
Defines the external attenuation to be considered in the calculation of the pwer results.
Remote command:
DISPlay[:WINDow<n>]:TRACe<t>:Y[:SCALe]:RLEVel:OFFSet on page 133
Settings
General Settings
4.1.1.4 Trigger Settings
The "Trigger Settings" contains settings to configure triggered measurements.
The "Trigger Settings" are part of the "Primary" tab of the "General Settings" dialog box.
Trigger Mode.................................................................................................................53
Trigger Port................................................................................................................... 54
Trigger Offset................................................................................................................ 54
Trigger Level................................................................................................................. 54
Trigger Mode
Selects the trigger source.
The R&S FS-K96 supports the following trigger sources.
●
Free Run The measurement starts immediately.
●
External The measurement starts when the external trigger signal meets or exceeds the specified external trigger level at the EXT TRIGGER/GATE input connector.
●
IF Power The measurement starts when the IF power meets or exceeds the specified trigger level. The IF Power trigger is available for measurements with a spectrum analyzer.
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Remote command:
TRIGger[:SEQuence]:MODE on page 135
Trigger Port
Selects the trigger port.
Trigger port selection is available for an external trigger source and for measurements with instruments that have more than one trigger port (for example R&S FSW)
Remote command:
TRIGger[:SEQuence]:PORT on page 136
Trigger Offset
Defines the time offset between the trigger signal and the start of the sweep.
A negative offset corresponds to a pre-trigger.
The trigger offset is available for all trigger sources except the Free Run source.
Remote command:
TRIGger[:SEQuence]:HOLDoff on page 134
Settings
General Settings
Trigger Level
Defines the threshold for the External or IF Power trigger source.
The unit of the trigger level is either V (external trigger) or dBm (IF power trigger).
Note that you can use automatic trigger level determination ("Auto Level)" when you use an IF Power trigger (spectrum analyzers only). If on, trigger threshold is deter­mined automatically by the software before each measurement.
Remote command: Trigger level (external trigger):
TRIGger[:SEQuence]:LEVel[:EXTernal] on page 134
Trigger level (IF power trigger):
TRIGger[:SEQuence]:LEVel:POWer on page 134
Automatic trigger level:
TRIGger[:SEQuence]:LEVel:POWer:AUTO on page 135
4.1.1.5 Input Settings
The "Input settings" contain settings to configure the input source of the signal ana­lyzer.
The "Input Settings" are part of the "Primary" tab of the "General Settings" dialog box.
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Source...........................................................................................................................55
Channel Filter................................................................................................................55
Bandwidth (6 dB)...........................................................................................................55
Filter Order.................................................................................................................... 55
Source
Selects the data source of the OFDM demodulator.
The R&S FS-K96 supports the following input sources.
●
RF Input Available for all supported instruments.
●
Analog Baseband Available for spectrum analyzers with an analog baseband input (R&S FSQ-B71) and oscilloscopes.
●
Digital I/Q Available for spectrum analyzers with a digital I/Q input (R&S FSQ-B17 or R&S FSV-B17).
●
File Reads the I/Q data from a file.
Remote command:
INPut:SELect on page 137
Settings
General Settings
Channel Filter
Selects the input filter preceding the OFDM demodulator.
●
Standard Uses the default filter of the connected instrument.
●
Adjustable Allows you to define the bandwidth and filter order of the lowpass filter.
Remote command:
INPut:FILTer:CHANnel[:STATe] on page 137
Bandwidth (6 dB)
Defines the bandwidth of an adjustable channel filter.
The bandwidth of the filter is defined as two times the 6 dB cutoff frequency. The avail­able range is between 0 Hz and the sample rate.
Note that a bandwidth near the sample rate can result in backfolding of higher fre­quency signal parts.
Remote command:
INPut:FILTer:CHANnel:BANDwidth on page 136
Filter Order
Defines the slope characteristics of the channel filter.
You can select from several predefined filter orders ("Low", "Normal", "High") or define a custom slope ("Manual").
Odd filter order values are rounded to the next higher even number.
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Remote command:
INPut:FILTer:CHANnel:ORDer on page 136
Settings
General Settings

4.1.2 Advanced Settings

The "Advanced Settings" contain settings to configure the signal input and some global measurement analysis settings.
The "Advanced Settings" tab is part of the "General Settings" dialog box.
● I/Q Settings ............................................................................................................ 56
● Analog Baseband Settings .....................................................................................56
● Digital I/Q Settings ................................................................................................. 58
● Advanced Level Settings.........................................................................................58
● Global Settings........................................................................................................59
4.1.2.1 I/Q Settings
The "I/Q settings" contain settings that control the I/Q data flow.
The "I/Q Settings" are part of the "Advanced" tab of the "General Settings" dialog box.
Swap I/Q....................................................................................................................... 56
Swap I/Q
Swaps the real (I branch) and the imaginary (Q branch) parts of the signal.
Remote command:
[SENSe:]SWAPiq on page 137
4.1.2.2 Analog Baseband Settings
The "Analog Baseband Settings" contain settings to configure the baseband input source.
The "Analog Baseband Settings" are part of the "Advanced" tab of the "General Set­tings" dialog box.
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Input Impedance........................................................................................................... 57
Balanced....................................................................................................................... 57
Lowpass........................................................................................................................ 57
Dither.............................................................................................................................57
Input Impedance
Selects the input impedance.
The available impedances depend on the type of instrument.
●
Spectrum analyzers support impedances of 50 Ω or 1 kΩ. Selecting the input impedance is available for analyzers with an analog baseband input.
●
Oscilloscopes support impedances of 50 Ω or 1 MΩ.
Remote command:
INPut:IQ:IMPedance on page 138
Balanced
Turns symmetric (or balanced) input on and off.
If active, a ground connection is not necessary. If you are using an assymetrical (unbalanced) setup, the ground connection runs through the shield of the coaxial cable that is used to connect the DUT
Available for spectrum analyzers with an analog baseband input.
Remote command:
INPut:IQ:BALanced[:STATe] on page 138
Settings
General Settings
Lowpass
Turns an anti-aliasing low pass filter on and off.
The filter has a cut-off frequency of 36 MHz and prevents frequencies above from being mixed into the usable frequency range. Note that if you turn the filter off, harmon­ics or spurious emissions of the DUT might be in the frequency range above 36 MHz and might be missed.
You can turn it off for measurement bandwidths greater than 30 MHz.
Available for spectrum analyzers with an analog baseband input.
Remote command:
[SENSe:]IQ:LPASs[:STATe] on page 139
Dither
Adds a noise signal into the signal path of the baseband input.
Dithering improves the linearity of the A/D converter at low signal levels or low modula­tion. Improving the linearity also improves the accuracy of the displayed signal levels. The signal has a bandwidth of 2 MHz with a center frequency of 38.93 MHz.
Available for spectrum analyzers with an analog baseband input.
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Remote command:
[SENSe:]IQ:DITHer[:STATe] on page 139
Settings
General Settings
4.1.2.3 Digital I/Q Settings
The "Digital I/Q Settings" contain settings to configure the digital I/Q input source.
The "Digital I/Q Settings" are part of the "Advanced" tab of the "General Settings" dia­log box.
Digital Input Sampling Rate...........................................................................................58
Full Scale Voltage......................................................................................................... 58
Digital Input Sampling Rate
Defines the data sample rate at the digital baseband input.
Available for spectrum analyzers with a digital I/Q input (R&S FSQ-B17 or FSV-B17).
Remote command:
INPut:DIQ:SRATe on page 140
Full Scale Voltage
Defines the voltage corresponding to the maximum input value of the digital baseband input.
Available for spectrum analyzers with a digital I/Q input (R&S FSQ-B17 or FSV-B17).
Remote command:
INPut:DIQ:RANGe[:UPPer] on page 139
4.1.2.4 Advanced Level Settings
The "Advanced Level Settings" contain settings to define the leveling of the R&S ana­lyzer.
The "Level Settings Advanced" are part of the "Advanced" tab of the "General Settings" dialog box.
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Auto Level Track Time.................................................................................................. 59
RF Attenuation.............................................................................................................. 59
El. Attenuation...............................................................................................................59
YIG Filter....................................................................................................................... 59
Auto Level Track Time
"Auto Level Track Time" specifies the sweep time used for the auto level measure­ments.
This parameter is editable only when RF input is selected and the "Auto Level" function is turned on.
Remote command:
CONFigure:POWer:AUTO:SWEep:TIME on page 140
RF Attenuation
"RF Attenuation" specifies the mechanical attenuation to be applied to the input RF sig­nal.
Attenuation is possible from 0 dB to 75 dB in steps of 5 dB.
RF attenuation is available for measurements with spectrum analyzers and if the input source is the RF input. If the "Auto Level" function is on, attenuation is unavailable.
Remote command:
INPut:ATTenuation on page 140
Settings
General Settings
El. Attenuation
"El. Attenuation" specifies the electrical attenuation to be applied to the input RF signal.
You can define the attenuation level manually or automatically by the software.
Electronic attenuation is possible from 0 dB to 30 dB in steps of 5 dB.
The electrical attenuator can be switched off completely.
Electronic attenuation is available for measurements with spectrum analyzers and if the input source is the RF input. If the "Auto Level" function is on, attenuation is unavailable.
Remote command:
INPut:EATT:STATe on page 142 INPut:EATT:AUTO on page 141 INPut:EATT on page 141
YIG Filter
"YIG Filter" specifies the state of the YIG filter in a spectrum analyzer.
The YIG filter is available for measurements with a spectrum analyzer.
Remote command:
INPut:FILTer:YIG[:STATe] on page 142
4.1.2.5 Global Settings
The "Global Settings" contain settings that apply to the overall measurement.
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The "Global Settings" are part of the "Advanced" tab of the "General Settings" dialog box.
Couple Screens.............................................................................................................60
Couple Screens
If "Couple Screens" is enabled, the markers on the top and bottom screen which have the same unit (e.g., frequency or symbol index) are coupled.
Remote: Not supported yet.
Settings
General Settings

4.1.3 Measurement Settings

The "Measurement Settings" contain settings to configure the way measurement results are displayed.
The "Measurement Settings" tab is part of the "General Settings" dialog box.
● Units........................................................................................................................60
● EVM........................................................................................................................ 62
● Error Frequency / Phase.........................................................................................63
4.1.3.1 Units
The "Units Settings" contain settings to select the unit for scaling the diagram axes in various result displays.
The "Units Settings" are part of the "Meas" tab of the "General Settings" dialog box.
EVM
Selects the unit for EVM results.
Available units: dB or %
●
dB Displays EVM results in dB.
●
% Displays EVM results in %.
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Remote command:
UNIT:EVM on page 143
Impulse Response
Selects the unit for channel impulse results.
●
Linear Displays the channel impulse results in a linear scale.
●
dB Displays the channel impulse results in a logarithmic scale (in dB).
Remote command:
UNIT:IRES on page 143
Symbol Axes
Selects the scale of time axes representing symbols.
●
Symbol Number Displays the time in terms of symbols.
●
Seconds Displays the time in seconds.
Remote command:
UNIT:SAXes on page 144
Settings
General Settings
Carrier Axes
Selects the scale of frequency axes representing carrier numbers.
●
Carrier Number Displays the frequency in terms of the carrier number.
●
Hertz Displays the frequency in Hertz.
Remote command:
UNIT:CAXes on page 142
Time Axes
Selects the scale of general time axes.
●
Seconds Displays the time in seconds.
●
Sample Time Displays the time in terms of the sample time.
●
Symbol Time Displays the time in terms of the symbol time.
Remote command:
UNIT:TAXes on page 144
Frequency Axes
Selects the scale of general frequency axes.
●
Hertz Displays the frequency in Hertz.
●
Sample Rate Displays the frequency in terms of the sample rate.
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1
0
2
1
N
i
i
EVM
N
1
0
1
N
i
i
EVM
N
●
Subcarrier Spacing Displays the frequency in terms of the subcarrier spacing.
Remote command:
UNIT:FAXes on page 143
Settings
General Settings
4.1.3.2 EVM
The "EVM" settings contain settings to define the calculation of the Error Vector Magni­tude (EVM).
The "Meas Settings" are part of the "Meas" tab of the "General Settings" dialog box.
Normalize EVM to
"Normalize EVM to" specifies the OFDM cells which are averaged to get the reference magnitude for EVM normalization (see Chapter 6.3.1, "Error Vector Magnitude (EVM)", on page 110 for details).
Available values:
RMS Pilots & Data, RMS Data, RMS Pilots, Peak Pilots & Data, Peak Data, Peak Pilots, None
Remote command:
[SENSe:]DEMod:EVMCalc:NORMalize on page 145
Frame Averaging
"Frame Averaging" specifies the method of averaging over multiple OFDM frames used to get the mean EVM values in the result list.
Frame Averaging Averaged EVM over N frames
Mean Square
RMS
Mean square averaging is consistent with the EVM calculation within one frame. How­ever, some standards, e.g. 802.11a, require RMS averaging.
Available values:
Mean Square, RMS
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Remote command:
[SENSe:]DEMod:EVMCalc:FAVerage on page 145
Settings
Demodulation Settings
4.1.3.3 Error Frequency / Phase
The "Error Frequency / Phase Settings" contain settings to configure frequency and phase error measurements.
The "Error Frequency / Phase" settings are part of the "Meas" tab of the "General Set­tings" dialog box.
Number of Symbols
"Number of Symbols" specifies the number of symbols per frame used for the evalua­tion of the sample wise frequency and phase error calculation. The upper limit is the Result Length minus one (Result Length – 1).
Remote command: Not supported yet.

4.2 Demodulation Settings

This section describes the demodulation settings of the software for running a correct measurement by means of OFDM system configuration and demodulation control options.
● Signal Description................................................................................................... 63
● Demodulation Control............................................................................................. 70

4.2.1 Signal Description

The "Signal Description" contains general settings to configure the software for the applied signal.
The "Signal Description" tab is part of the "Demod Settings" dialog box.
● System Configuration..............................................................................................63
● Symbol Characteristics........................................................................................... 66
● Preamble Symbol Characteristics...........................................................................68
● Frame Characteristics.............................................................................................69
● Filter Characteristics............................................................................................... 69
4.2.1.1 System Configuration
The "System Configuration" contains settings to configure the OFDM system.
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The "System Configuration" is part of the "Signal Description" tab of the "Demod Set­tings" dialog box.
Analysis Mode...............................................................................................................64
Manual Configuration.................................................................................................... 64
Configuration File.......................................................................................................... 64
Configuration with Wizard............................................................................................. 65
Settings
Demodulation Settings
Analysis Mode
"Analysis Mode" selects the type of multicarrier waveform you would like to test.
The following signal types are supported.
●
OFDM For more information about OFDM waveforms see Chapter 6.1.1, "OFDM", on page 96.
●
GFDM For more information about GFDM waveforms see Chapter 6.1.2, "GFDM", on page 103.
●
UFMC For more information about UFMC waveforms see Chapter 6.1.3, "UFMC", on page 104.
The waveform you select determines the parameters that are available in the "Demod­ulation" dialog box ("Signal Description" and "Demodulation Control" tabs).
Remote command:
[SENSe:]DEMod:AMODe on page 146
Manual Configuration
"Manual Configuration" allows to specify an FDM system without using a system con­figuration file. The basic FDM parameters can be entered manually. If manual configu­ration is enabled, no frame synchronization can be performed. EVM or Channel mea­surements are not available. The constellation diagram will still show a rotation.
Remote command:
CONFigure:SYSTem:MANual on page 146
Configuration File
"Configuration File" allows loading a configuration file which defines the specific FDM system. Pressing ‘...’ opens a file manager. The configuration file contains the system name and a system description, which are displayed within the text fields.
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Note: It is also possible to load a configuration file by drag-and-drop.
Remote command:
MMEMory:LOAD:CFGFile on page 146
Configuration with Wizard
"Generate Configuration File" opens a dialog that displays the necessary settings for a burst detection and a coarse timing synchronization. Based on these results, it is then possible to start the "R&S FS-K96 Configuration File Wizard" (see Figure 5-5) and to generate a configuration file.
(Note that the Wizard is not supported for UFMC and GFDM waveforms.)
The dialog box consists of the following elements.
●
Input Settings
For more information see Chapter 4.1.1.5, "Input Settings", on page 54.
●
Data Capture Settings
Settings
Demodulation Settings
For more information see Chapter 4.1.1.2, "Data Capture Settings", on page 51.
●
General Demodulation Settings
●
OFDM Symbol Characteristics
For more information see Chapter 4.2.1.2, "Symbol Characteristics", on page 66.
●
Visualization
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Shows a preview of the signal and probable errors.
Settings
Demodulation Settings
4.2.1.2 Symbol Characteristics
The "Symbol Characteristics" contain settings to configure the OFDM symbol in the time domain.
The "Symbol Characteristics" are part of the "Signal Description" tab of the "Demod Settings" dialog box.
FFT Length....................................................................................................................66
Cyclic Prefix Length...................................................................................................... 66
Cyclic Prefix Configuration............................................................................................ 67
FFT Length
"FFT Length" specifies the length of the FFT area of an FDM symbol in time domain in number of samples.This parameter is editable only when manual configuration is selected.
Remote command:
CONFigure[:SYMBol]:NFFT on page 148
Cyclic Prefix Length
"Cyclic Prefix Length" specifies the length of the Cyclic Prefix area of an OFDM or GFDM symbol in time domain in number of samples.
Note that in case of an UFMC waveform, the "Cyclic Prefix Length" has no effect.
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Remote command:
CONFigure[:SYMBol]:NGUard<guardnum> on page 148
Cyclic Prefix Configuration
"Cyclic Prefix Configuration" opens a dialog that allows you to configure the non-con­ventional cyclic prefix mode.
Available for OFDM waveforms.
Settings
Demodulation Settings
In the conventional cyclic prefix mode, all FDM symbols have the same cyclic prefix length. In the non-conventional cyclic prefix mode, some OFDM symbols have different cyclic prefix lengths than others. One well-known FDM system, where different cyclic prefix lengths can occur in one frame is e.g. LTE.
In the non-conventional case, we distinguish between the periodic mode and the non­periodic mode.
In the periodic mode (see Figure 4-2), one "Slot" that consists of the two ranges that can be defined in this dialog is repeated over and over until the number of symbols specified by the result range parameter is reached (e.g. LTE).
Figure 4-2: Non-Conventional Cyclic Prefix Case: Periodic Mode
●
Number of Symbols (Range 1) (1) Specifies the length of the first range in symbols.
●
First Cyclic Prefix Length (2) Specifies the length of the first cyclic prefix in samples.
●
Number of Symbols (Range 2) (3) Specifies the length of the second range in symbols.
●
Second Cyclic Prefix Length (4) Specifies the length of the second cyclic prefix in samples.
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In the non-periodic case (see Figure 4-3), a fixed preamble has a different cyclic prefix length than the rest of the frame (e.g. 802.11ac). In this case, the length of the second range is extended till the end of the demodulated frame. Therefore, the length of the second range cannot be specified in this case.
Figure 4-3: Non-Conventional Cyclic Prefix Case: Non-Periodic Mode
Remote command: Cyclic prefix mode:
CONFigure[:SYMBol]:GUARd:MODE on page 147
Periodic cyclic prefix:
CONFigure[:SYMBol]:GUARd:PERiodic on page 148
Number of symbols:
CONFigure[:SYMBol]:GUARd<guardnum>:NSYMbols on page 147
Cyclic prefix length:
CONFigure[:SYMBol]:NGUard<guardnum> on page 148
Settings
Demodulation Settings
4.2.1.3 Preamble Symbol Characteristics
The "Preamble Symbol Characteristics" contain settings to configure the preamble in the time domain.
The "Preamble Symbol Characteristics" are part of the "Signal Description" tab of the "Demod Settings" dialog box.
The"Preamble Symbol Characteristics" have an effect if you have turned on preamble based time synchronization.
Block Length................................................................................................................. 68
Frame Offset................................................................................................................. 69
Block Length
"Block Length" specifies the length of one data block within the repetitive preamble in number of samples.
Note that the "Block Length" has no effect for measurements on UFMC waveforms.
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Remote command:
CONFigure:PREamble:BLENgth on page 151
Frame Offset
"Frame Offset" specifies the time offset from the preamble start to the actual frame start in number of samples.
Note that the "Frame Offset" has no effect for measurements on UFMC waveforms.
Remote command:
CONFigure:PREamble:FOFFset on page 151
Settings
Demodulation Settings
4.2.1.4 Frame Characteristics
The "Frame Characteristics" contain settings to configure the OFDM frame.
The "Frame Characteristics" are part of the "Signal Description" tab of the "Demod Set­tings" dialog box.
Frame Length................................................................................................................69
Frame Length
"Frame Length" displays the length of the configured FDM frame. This is the maximum result length for which a configuration exists. The parameter has no meaning in manual mode.
4.2.1.5 Filter Characteristics
The "Filter Characteristics" contain settings to configure the filters for GFDM and UFMC signals.
The "Filter Characteristics" are part of the "Signal Description" tab of the "Demod Set­tings" dialog box.
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Filter Type..................................................................................................................... 70
Roll-Off.......................................................................................................................... 70
Overlapping...................................................................................................................70
Filter Length.................................................................................................................. 70
Stop Band Attenuation.................................................................................................. 70
Filter Type
"Filter Type" shows the type of filter that is applied for the measurement.
In case of GFDM waveforms, you can select an RC (raised-cosine) or RRC (root­raised-cosine) filter.
In case of UFMC waveforms, the filter is always a Chebyshev filter.
Filter selection is not available for OFDM waveforms.
Remote command: UFMC: not supported GFDM: [SENSe:]DEMod:GFDM:FILTer:TYPE on page 150
Roll-Off
"Roll-Off" defines the roll-off (or weighting) factor for the filter.
Available for GFDM waveforms.
Remote command:
[SENSe:]DEMod:GFDM:FILTer:ROFactor on page 149
Settings
Demodulation Settings
Overlapping
"Overlapping" defines the width of the subcarrier filter in the frequency domain.
Available for GFDM waveforms.
Remote command:
[SENSe:]DEMod:GFDM:FILTer:OLAPping on page 149
Filter Length
"Filter Length" defines the length of the applied filter in samples.
Available for UFMC waveforms.
Remote command:
[SENSe:]DEMod:UFMC:FILTer:LENGth on page 150
Stop Band Attenuation
"Stop Band Attenuation" defines a sidelobe magnitude relative to the mainlobe magni­tude in dB.
Remote command:
[SENSe:]DEMod:UFMC:FILTer:SBATten on page 150

4.2.2 Demodulation Control

The "Demodulation Control" contains advanced demodulation settings.
The "Demodulation Control" tab is part of the "Demod Settings" dialog box.
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● General Settings..................................................................................................... 71
● Synchronization Settings.........................................................................................71
● Compensation Settings...........................................................................................72
● Advanced Settings.................................................................................................. 73
Settings
Demodulation Settings
4.2.2.1 General Settings
The "General Demodulation Settings" contain settings to control the position and length of the OFDM frame in the capture buffer.
The "General Demodulation Settings" are part of the "Demodulation Control" tab of the "Demod Settings" dialog box.
Burst Search................................................................................................................. 71
Maximum Frames to Analyze........................................................................................71
Result Length................................................................................................................ 71
Burst Search
"Burst Search" specifies whether the demodulator shall search for power bursts before time synchronization. If enabled, the successive demodulation steps are restricted to the signal areas which contain significant power. For continuous signals this parameter has to be disabled.
Remote command:
[SENSe:]DEMod:FORMat:BURSt on page 151
Maximum Frames to Analyze
"Max. Frames to Analyze" specifies the maximum number of frames which are ana­lyzed within one capture buffer.
Remote command:
[SENSe:]DEMod:FORMat:MAXFrames on page 152
Result Length
"Result Length" specifies the number of analyzed symbols in one frame. This number must be equal or lower than the Frame Length specified in the System Description menu. In order to guarantee stable demodulation, its lower limit is 4.
Remote command:
[SENSe:]DEMod:FORMat:NOFSymbols on page 152
4.2.2.2 Synchronization Settings
The "Synchronization Settings" contain settings to control synchronization during the demodulation process.
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The "Synchronization Settings" are part of the "Demodulation Control" tab of the "Demod Settings" dialog box.
Time Synchronization....................................................................................................72
Parameter Estimation....................................................................................................72
Modulation Detection.................................................................................................... 72
Time Synchronization
"Time Synchronization" specifies the synchronization method in time domain. The cyclic prefix method performs a correlation of the cyclic prefix with the end of the FFT interval. The preamble method searches for the repetitive preamble blocks.
In case of GFDM waveforms, the synchronization is always done with a "Cyclic Prefix".
In case of UFMC waveforms, the synchronization is always done with a "Preamble".
Remote command:
[SENSe:]DEMod:TSYNc on page 153
Settings
Demodulation Settings
Parameter Estimation
"Parameter Estimation" specifies the mode of synchronization in the frequency domain. In the manual configuration mode without a configuration file, the parameter estimation is forcefully switched off. If a configuration file is loaded, Pilot Aided synchronization or Pilot And Data Aided synchronization can be selected. Pilot Aided synchronization uses only the predefined pilot cells as reference signal. The Pilot And Data Aided syn­chronization uses both pilots and decided data cells for an additional synchronization step.
Remote command:
[SENSe:]DEMod:FSYNc on page 152
Modulation Detection
"Modulation Detection" specifies the operation mode of the automatic modulation detection for the data cells. If Configuration File is selected, the modulation matrix within the system configuration file is evaluated. The symbolwise modulation detection determines a common modulation format for all data cells within one FDM symbol. The carrierwise modulation detection determines a common modulation format for all data cells within one FDM carrier.
Remote command:
[SENSe:]DEMod:MDETect on page 153
4.2.2.3 Compensation Settings
The "Compensation Settings" contain settings to control error compensation for the EVM measurement.
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The "Compensation Settings" are part of the "Demodulation Control" tab of the "Demod Settings" dialog box.
Phase Tracking............................................................................................................. 73
Timing Tracking.............................................................................................................73
Level Tracking...............................................................................................................73
Channel Compensation.................................................................................................73
Phase Tracking
"Phase Tracking" specifies whether or not the measurement results should be com­pensated for common phase error.The compensation is done on a per-symbol basis.
Remote command:
[SENSe:]TRACking:PHASe on page 154
Settings
Demodulation Settings
Timing Tracking
"Timing Tracking" specifies whether or not the measurement results should be com­pensated for sample clock deviations.
The compensation is done on a per-symbol basis.
Remote command:
[SENSe:]TRACking:TIME on page 155
Level Tracking
"Level Tracking" specifies whether or not the measurement results should be compen­sated for power level deviations.
The compensation is done on a per-symbol basis.
Remote command:
[SENSe:]TRACking:LEVel on page 154
Channel Compensation
"Channel Compensation" specifies whether or not the measurement results should be compensated for the channel transfer function. The compensation is done on a per­carrier basis.
Remote command:
[SENSe:]COMPensate:CHANnel on page 154
4.2.2.4 Advanced Settings
The "Advanced Settings" contain settings to control various signal processing charac­teristics of the software.
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The "Advanced Settings" are part of the "Demodulation Control" tab of the "Demod Settings" dialog box.
FFT Shift relative to Cyclic Prefix Length...................................................................... 74
Maximum Carrier Offset................................................................................................ 74
Cyclic Delay.................................................................................................................. 74
FFT Shift relative to Cyclic Prefix Length
"FFT Shift rel. to CP length" allows for shifting the FFT start sample within the guard interval. This is useful if relevant parts of the channel impulse response fall outside the cyclic prefix interval.
Settings
Demodulation Settings
FFT Shift = 1.0
FFT Shift = 0.0
N
G
Not available for GFDM waveforms.
Remote command:
[SENSe:]DEMod:FFTShift on page 155
Maximum Carrier Offset
"Maximum Carrier Offset" defines the search range of the frame synchronization in fre­quency direction. If set to zero, the center frequency offset must be less than half the carrier distance. Higher values allow higher frequency offsets, but slow down the mea­surement time.
Remote command:
[SENSe:]DEMod:COFFset on page 156
Cyclic Delay
"Cyclic Delay" defines a cyclic shift of the FFT part of each OFDM symbol on the trans­mitter side before adding the cyclic prefix. This known shift should be compensated in the receiver to get a correct channel phase response.
Remote command:
[SENSe:]DEMod:CDD on page 155
N
FFT
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5 System Configuration File

The R&S FS-K96 Software has to know the structure of the OFDM system in order to be able to demodulate an OFDM signal correctly. By "structure", we refer to the com­plete description of the OFDM system:
●
the number of subcarriers (i.e. the FFT size)
●
the number of symbols
●
the number of samples in the cyclic prefix (also referred to as guard length)
●
the position (carrier number, symbol number) of the
– pilot symbols
– data symbols
– zero symbols
– don’t care symbols
●
the modulation format of the data symbols (e.g. QPSK, 16QAM etc.)
●
the value of the pilot symbols
●
(optional: the definition of the preamble)
System Configuration File
Matlab Configuration File Format
This section describes the format and generation of the OFDM system configuration file which can be loaded within the system configuration tab of the demodulation setup window.
The OFDM configuration file can be either stored in Matlab *.mat format (see Chap-
ter 5.1, "Matlab Configuration File Format", on page 75) or in an XML *.xml format
(see Chapter 5.2, "XML Configuration File Format", on page 84).
● Matlab Configuration File Format............................................................................75
● XML Configuration File Format............................................................................... 84

5.1 Matlab Configuration File Format

The OFDM configuration can be stored in a Matlab *.mat format which contains the structure 'stOfdmCfg'. The following table lists the elements of the structure and the sub-structures.
Instead of manual generation of the configuration structure it is recommended to use the additionally provided OFDM system class and its methods.
Structure: stOfdmCfg
Parameter Type Meaning Example
sVersion string Version identifier of the interface for-
mat.
sSystem string Identifier of the OFDM system. 'Wimax IEEE 802.16-2004'
sDescription string Additional information about the
OFDM system.
'R&S_OVSA_IFC_V0.1'
'Uplink with subchannelisa­tion 8, 20 symbols, special 17QAM modulation'
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Structure: stOfdmCfg
System Configuration File
Matlab Configuration File Format
stPreamble structure Optional definition of a repetitive pre-
amble symbol for time synchroniza­tion.
iNfft int32 Number of samples in one FFT
block.
iNg int32 Number of samples in the cyclic pre-
fix block.
iNOfSymbols int32 Number of symbols described by this
system definition. This is also the maximum result range.
meStructure [iNOfSymbols X
iNfft] matrix of int8
vstDataConst Array of stCon-
stellation
viDataConstPtr Vector of uint8 For each 'Data' entry in meStructure
Time-Frequency matrix containing the type of each cell in the OFDM system.
0: Zero
1: Pilot
2: Data
3: Don't Care
Array of constellation structures; one constellation structure for each data constellation.
this vector contains the number of the constellation used for the data cell. meStructure is evaluated row wise.
256
16
100
[0,0,1,1,1,1,1,1,1,1,0,0;
0,0,2,2,1,2,2,1,2,2,0,0]
[0,0,1,1,2,2]
vfcPilot Vector of com-
plex float32
eAnalysisMode uint8 Waveform type.
Structure: stPreamble
Parameter Type Meaning Example
iBlockLength int32 Length of the repetitive block. 16
iFrameOffset int32 Offset of the first sample of the
For each 'Pilot' entry in meStructure this vector contains the complex pilot value. meStructure is evaluated row wise.
OFDM = 0
GFDM = 1
UFMC = 2
preamble symbol to the first sample of the first symbol defined in the allocation matrix.
[1+j,-1-j,-1+j,1-j,1+j,-1-j,-1+j, 1-j,
1+3j,-1-j]
1
0
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Structure: stConstellation
Parameter Type Meaning Example
sName string Constellation name. 'QPSK'
System Configuration File
Matlab Configuration File Format
vfcValue Vector of complex
float32
Structure: stFilter
Parameter Type Meaning Example
eFilterType uint8 Filter type.
iFilterLength int32 Filter length. 10
fStopBandAttenuation single Stop band attenuation. 60 [dB]
fRollOff single RRC roll-off factor. 0.1
iOverlapping int32 Overlapping. 2
Vector of complex val­ued constellation points.
RRC = 1
RC = 2
[-1-j,-1+j,1+j,1-j]
0
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Debugging the system configuration file
An easy way to take a quick look at your allocation matrix (meStructure) in your sys­tem configuration file is via the Matlab function imagesc().
Example:
MyConfigFile = load(<Configfilename>);imagesc(MyConfigFile.stOfdmCfg.meStructure);
The plot for the examplary Wimax Configuration file that is included in your software then looks as follows:
System Configuration File
Matlab Configuration File Format

5.1.1 OFDM System Class

The R&S FS-K96 provides a Matlab class which supports the user in creating the con­figuration file, so that he does not need to generate the configuration structure man­ually. It is recommended to use this class. The Matlab class @OfdmSys is stored in the installation directory @OfdmSys
and contains the following functions:
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Table 5-1: Overview of the Member Functions of the Matlab Class @OfdmSys
Member Function Description
System Configuration File
Matlab Configuration File Format
c = OfdmSys()
c = OfdmSys(iNOfSymbols, iNfft, iNg)
c = Init (iNOfSymbols, iNfft, iNg)
c = SetSystem (sSystem)
c = SetDescription (sDescription)
c = SetConstellation (vfcValue, sName)
c = SetCell (iSymbol, iCarrier, 'Zero')
c = SetCell (iSymbol, iCarrier, 'Pilot', fcValue)
c = SetCell (iSymbol, iCarrier, 'Data', sConstName)
c = SetCell (iSymbol, iCarrier, 'DontCare')
c = SetPreamble (iBlockLength, iFrameOffset)
c = LoadConfigFile (sFileName)
c = SaveConfigFile (sFileName)
Default Constructor and parameterized constructor
Initialize a new system configuration
Describe the OFDM system
Define a constellation vector
Define a specific cell of the OFDM system
Define a repetitive preamble symbol
Load or save a system configuration file
The following part describes the functions and the input parameters of the Matlab Class @OfdmSys in detail. Furthermore a short example is given for all of the func­tions.
With the information provided below, the user can write his own *.m file. Running the *.m file creates the custom *.mat OFDM configuration file. This *.mat file contains the configuration data and can be loaded into the R&S FS-K96 OFDM Vector Signal Analysis Software.
INIT This function initializes the System Configuration Class
c = Init(c, iNOfSymbols, iNfft, iNg);
Input parameter
Output parameter
Example 1
Example 2
c
iNOfSymbols
iNfft
iNg
c
cOfdmSys = OfdmSys();
cOfdmSys = Init(cOfdmSys, 100, 64, 16);
cOfdmSys = OfdmSys(100, 64, 16);
Input object
Number of OFDM symbols in one frame included in the configura­tion file. This is the maximum frame length to be analyzed
FFT length in number of samples
Cyclix prefix length in number of samples
Modified object
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Support for cyclic prefix configuration
At the moment, only the conventional cyclic prefix mode is supported in the *.mat configuration file format. That means, that OFDM systems with symbols of different cyclic prefix length (e.g. LTE) are currently not supported in the *.mat configuration file format. It is recommended to either use the *.xml configuration file format for these setups or to enter the cyclic prefix configuration manually after the *.mat config­uration file has been loaded.
SET_SYSTEM This function sets the system name string.
System Configuration File
Matlab Configuration File Format
c = SetSystem(c, sSystem);
Input parameter
Output parameter
Example
SET_DESCRIPTION This function sets the system description string
Input parameter
Output parameter
Example
SET_CONSTELLATION This function sets a constellation vector
Input parameter
c
sSystem
c
cOfdmSys = SetSystem(cOfdmSys,'WiMAX_802_16');
c = SetDescription(c, sDescription);
c
sDescription
c
cOfdmSys = SetDescription(cOfdmSys,'WiMAX 802.16');
c = SetConstellation(c, sName)
c = SetConstellation(c, sName, vfcValue)
c
Input object
String containing the name of the system
Modified class
Input object
String containing the name of the sys­tem
Modified class
Input object
Output parameter
Example
sName Name of the constellation
vfcValue
c
cOfdmSys = SetConstellation(cOfdmSys, 'QPSK', 1/sqrt(2) * [1+j,-1+j,-1-j,1-j]);
Complex value with the constellation symbols. Can be omitted for unknown modulation areas
Modified class
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SET_CELL This function defines one cell in the time frequency matrice (a
System Configuration File
Matlab Configuration File Format
specific cell of the OFDM system)
c = SetCell(c, viSymbol, viCarrier, 'Zero')
c = SetCell(c, viSymbol, viCarrier, 'Pilot', vfcValue)
c = SetCell(c, viSymbol, viCarrier, 'Data', sConstName)
c = SetCell(c, viSymbol, viCarrier, 'DontCare')
Input parameter
Output parameter
Example
Special requirements The Generic OFDM analyzer has a minimum requirement about the
SET_PREAMBLE This function sets the repetitive preamble parameters (optional
Input parameter
c
viSymbol
viCarrier
'Pilot', vfcValue
'Data', sConstName
c
cOfdmSys = SetCell(cOfdmSys, 4, [-26:-22,-20:-8,-6:
-1,1:6,8:20,22:26], 'Data', 'BPSK');
number and the location of the pilot cells:
The number of pilot cells must be at least 4
At least two different symbols must contain pilot cells
At least two different carriers must contain pilot cells
parameter needed for time synchronization on preamble)
c = SetPreamble(c, iBlockLength, iFrameOffset)
c
Input object
Symbol numbers of cells
Carrier numbers of cells
Complex pilot values
Name of the data constellation
Modified object
Input object
iBlockLength Length of one repetitive block in num-
ber of samples
iFrameOffset
Output parameter
Example
Special requirements The definition of a repetitive preamble is optional and not necessary if
SAVE_CONFIG_FILE This function generates and saves a configuration file from the
Input parameter
c
cOfdmSys = SetPreamble(cOfdmSys, 16, 0);
cyclic prefix synchronisation is used.
If the offset is zero or negative, the preamble is also contained within the frame and is used for further estimation processes.
current system configuration to be used within R&S FS-K96 Soft­ware.
c = SaveConfigFile(c, sFileName)
c
Offset of preamble start to frame start
Modified object
Input object
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SAVE_CONFIG_FILE This function generates and saves a configuration file from the
System Configuration File
Matlab Configuration File Format
current system configuration to be used within R&S FS-K96 Soft­ware.
Output parameter
Example
LOAD_CONFIG_FILE This function configures the OfdmSys object from a configura-
Input parameter
Output parameter

5.1.2 Generate I/Q Data Files

The following part describes how to generate *.iqw-files (data format of R&S Signal Analyzers) and how to convert these files to *.wv-files (data format for arbitrary wave­form generator of R&S Signal Generators). With this description the user obtains a complete R&S test solution for signal generation and analysis of generic OFDM sig­nals.
sFileName
c
File name of the configuration file
Modified object
SaveConfigFile(cOfdmSys, 'example.mat');
tion file.
c = LoadConfigFile(c, sFileName)
c
sFileName
c
Input object
File name of the configuration file
Modified object
R&S Signal Analyzer R&S Signal Generator
Configuration
File
5.1.2.1 I/Q data files for R&S Signal Analyzers (*.iqw-file) – ofdmsys_generator.m
Generation of Conversion to
*.iqw file *.wv file
The iqw files can be used to test the configuration file and make first measurements with the generated configuration file.
In real applications the user needs very often a signal generator which can generate the signal. Therefore the second part of this section describes how to convert the iqw-file to a wv-file which can be loaded into the arbitrary waveform generator of R&S vector signal generators.
The Matlab tools directory of R&S FS-K96 contains the file ofdmsys_generator.m. This file generates a test signal from a given configuration file and saves the signal as *.iqw (iiii,qqqq...) file for use in R&S FS-K96. This iqw-file is stored in the same direc­tory as the ofdmsys_generator.m file and the filename equals the configuration file name with 'iqw' as file extension.
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Ofdmsys_generator.m This function generates an I/Q data file (iqw-file), which can be
System Configuration File
Matlab Configuration File Format
loaded into R&S FS-K96, from any configuration file
vfcSignal = ofdmsys_generator(sConfigFileName,iNOfFrames, iNOfIdleSymbols)
Input parameter
Output parameter
Examples
5.1.2.2 I/Q data files for R&S Signal Generators (*.wv-file) – mat2wv.m
sConfigFileName
iNOfFrames
iNOfIdleSymbols
vfcSignal
% Generation of a continuous signal
ofdmsys_generator(‘example.mat’, 2, 0);
% Generation of a bursted signal
ofdmsys_generator(‘example.mat’, 2, 1);
Configuration file name
Number of frames to be gener­ated
Number of idle symbols between bursts and at start and end of sig­nal
Generated signal vector
R&S FS-K96 offers another helpful file within the Matlab tools directory: mat2wv.m. This file automatically converts the *.mat file into a *.wv file which can be used with R&S signal generators. This wv-file is stored in the same directory as the mat2wv.m file and the filename equals the mat file name with 'wv' as file extension.
To use this tool two steps have to be performed:
1. Execute ofdmsys_generator.m to obtain the generated signal vector
vfcSignal out of the configuration file. This signal vector is needed in the second step.
2. Execute mat2wv.m to obtain the wanted *.wv file.
mat2wv.m This function generates an I/Q data file (wv-file), which can be
loaded into the arbitrary waveform generator of R&S Signal Gen­erators, from a Matlab vector
mat2wv(vfcSignal, sFilename, fSampleRate, bNormalize)
Input parameter
vfcSignal
sFilename
fSampleRate
Input data vector
Filename of the generated wave­form file
Sample rate of the signal in Hz
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mat2wv.m This function generates an I/Q data file (wv-file), which can be
System Configuration File
XML Configuration File Format
loaded into the arbitrary waveform generator of R&S Signal Gen­erators, from a Matlab vector
Examples
bNormalize
vfcSignal = ofdmsys_generator(‘example.mat’, 2, 0);
mat2wv(vfcSignal, ‘example.wv’, 11.2e6, True);
True: The signal is normalized by the max. magnitude
False: The signal is not normal­ized. The maximum magnitude of the signal shall not exceed 1.0.
Afterwards the signal can be loaded into the arbitrary waveform generator.
Figure 5-1: Arbitrary Waveform Generator of R&S SMU200A

5.2 XML Configuration File Format

The OFDM configuration can be stored in an *.xml format which contains all the nec­essary information about the OFDM signal, e.g. number of carriers, used modulations, pilot symbol positions, etc..
In order to generate such a configuration file, Rohde&Schwarz provides the R&S FS­K96 Configuration File Wizard. Provided that you already have a signal that you want to measure, you can do a coarse timing synchronization of your signal. Using this sam­ple signal, the R&S FS-K96 Configuration File Wizard helps you to extract the neces­sary OFDM system parameters.
First, capture the signal you want to measure and then go to MAIN "DEMOD SET­TINGS" and select the "System Description" tab. Then, click on "Generate Configura­tion File".
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The following dialog will be shown, which displays all necessary settings for a burst detection and coarse timing synchronization:
System Configuration File
XML Configuration File Format
Figure 5-2: Necessary Settings to Prepare the Data for the R&S FS-K96 Configuration File Wizard
Enter the necessary settings and use the Refresh button to check whether your Time Sync is accurate. Furthermore, if your signal is bursted, enter the correct number of symbols per frame, i.e. ensure that the green bar in the capture buffer preview covers the whole burst.
Figure 5-3: Correct
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Figure 5-4: Incorrect
Subsequently, you can start the R&S FS-K96 Configuration File Wizard by clicking on the lower button. It will then start, preconfigured with your current signal and settings.
System Configuration File
XML Configuration File Format
Figure 5-5: R&S FS-K96 Configuration File Wizard

5.2.1 Overview of the R&S FS-K96 Configuration File Wizard

The goal of the R&S FS-K96 Configuration File Wizard is to help you describe your sig­nal. It enables allocation of pilot symbols and data symbols with a chosen modulation. After you have allocated all your cells, the R&S FS-K96 Configuration File Wizard can export an *.xml file that can later be loaded as configuration file into the R&S FS-K96 Software.
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The GUI of the R&S FS-K96 Configuration File Wizard consists of five main areas:
1. Step-by-Step: The step-by-step bar guides the user through the necessary steps
in generating a configuration file. Please note that steps 5 and 6 need to be repea­ted until all cells are allocated.
2. Constellation View: The constellation diagram on the left hand side visualizes the
loaded signal in the I/Q plane. It is possible to zoom in and/or to select points that are then highlighted in the Matrix View area. Pressing the Ctrl-key on your key­board, allows you to add further cells to your selection. The Constellation View area contains a toolbar. On the left hand side, you can toggle between zoom and selection mode. On the right hand side, you can choose which constellation points should be visible:
● Enabling the icon with the eye and the non-filled check displays all the constel­lation points that are not yet allocated.
● Enabling the icon with the eye and the green filled check displays all the con­stellation points that are already allocated.
System Configuration File
XML Configuration File Format
3. Matrix View: The matrix view area displays the 2D representation of the signal. The y-axis represents the time direction (unit: symbols), the x-axis represents the subcarriers. The matrix view can be toggled between "Frame Power" and "Alloca­tion Matrix". It is possible to select an area either by clicking the mouse or with the context menu. Pressing the Ctrl-key on your keyboard, allows you to add further cells to your selection. The cells within the selected area will then be highlighted in the Constellation View.The Frame Power matrix view contains a toolbar where you can choose between a black and white colormap and a jet colormap.
The Allocation Matrix view contains a toolbar where you can choose whether to show the highlighted constellation points in the allocation matrix
4. General Information: This area displays the general information on your system configuration. It is possible to choose a custom system name and system descrip­tion by clicking on the entries. Both will later be stored in your configuration file.
5. Hint Area: Clicking on the "Light Bulb" icon, the software will give useful hints about the next steps that are necessary to generate a configuration file.
5.2.1.1 Quick Start Guide for the R&S FS-K96 Configuration File Wizard
This section will help you to quickly become familiar with the R&S FS-K96 Configura­tion File Wizard. A WLAN 802.11a signal is used as an example.
Start from Preset in the R&S FS-K96 Software and load the file WlanA_64QAM.iq.tar (you can find this file in your install directory in the folder
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\SIGNALS). Follow the steps as described in Chapter 5.2, "XML Configuration File
Format", on page 84 and ensure that the settings in the R&S FS-K96 Software are
according to the screenshot in Figure 5-2. Open the R&S FS-K96 Configuration File Wizard directly from the R&S FS-K96 Software.
Let us now focus on the step-by-step bar. Since you have started the R&S FS-K96 Configuration File Wizard directly from the R&S FS-K96 Software, it is already precon­figured with your signal. Hence, you can skip step 1. As the WLAN signal is a burst signal, you can assume that one frame is defined by one burst. Therefore, you can also skip step 2 and proceed straight to step 3.
Synchronization of the Signal (Step 3)
Click on the "Synchronization" icon, and subsequently on the Auto button of the shown dialog. The signal will automatically synchronize.
System Configuration File
XML Configuration File Format
In the case that you work with a signal where the automatic synchronization fails, try to use the sliders to get a clear view of the constellation diagram:
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System Configuration File
XML Configuration File Format
Figure 5-6: Example of a constellation diagram for a synchronized WLAN signal
Gain Adjustment (Step 4)
Click on the "Gain Adjustment" icon. The following dialog will be shown:
The goal of this step is to provide an overall scaling estimation for your signal. First, you have to decide on a reference constellation. By reference constellation, we refer to a constellation that occurs in several cells of your signal. It is recommended to decide on the constellation that occurs in most cells. You can easily find this constellation by making use of the selection mode and checking the number of highlighted cells in the Matrix View. For the current WLAN sample signal, the best reference constellation is 64QAM. After you have selected 64QAM as reference constellation, press the Auto button to perform automatic gain estimation. The result of this step is that all constella­tion points belonging to the reference constellation are approximately in the center of the constellation markers.
In the case that you work with a signal where the automatic gain correction fails, try to adjust the radius and click on the Auto button again. If the automatic gain correction still fails, try another reference constellation or use the Gain slider to center the points in the constellation markers manually.
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System Configuration File
XML Configuration File Format
Figure 5-7: Example of a Constellation Diagram for a Synchronized WLAN Signal after the Gain Syn-
chronization
Cell Selection and Allocation (Step 5 and 6)
Your next goal is to allocate selected points as pilot symbols, data symbols, "zeros" or "Don't care" symbols. You should already have selected constellation points from the gain synchronization procedure. Check their position in the "Frame Power" matrix and decide whether they are pilot symbols or data symbols. Go to step 6, and look at the colored area of the GUI. There, you can choose your allocation type. For the WLAN sample signal, you should allocate the 64QAM cells as data symbols. Optionally, you can assign a name to this specific allocation by typing into the text box. Then, click on the "Check" icon to actually do the allocation.
The constellation cells that have just been allocated will now disappear from the Con­stellation View. You can toggle their visibility by using the
icon. Note that you can
also overwrite already allocated cells with another allocation.
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System Configuration File
XML Configuration File Format
Figure 5-8: Example of a Constellation Diagram for a Synchronized WLAN Signal after the Allocation
of the 64QAM Cells as Data Symbols
Now go back to step 5 and proceed with the allocation of the residual points, e.g. choose "Zero" as "Constellation Marker" and allocate the constellation points in the center of the diagram as "Zero" symbols (step 6).
Go back again to step 5 and investigate the remaining points shown in the Constella­tion View. For the WLAN sample signal, you can select the BPSK symbols with the mouse. When taking a look at the Allocation Matrix, you will see that these BPSK sym­bols are used at the very beginning of the frame and at certain carriers. From this infor­mation, you can conclude that these symbols are probably pilot symbols.
Figure 5-9: Selection of the BPSK Symbols with the Mouse
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Hence, you can select BPSK constellation markers and allocate these cells as pilot symbols.
If you have worked with the WLAN sample signal, you will now have very few cells left for allocation. Go back to step 5, select all residual cells with the mouse in the Constel­lation View and allocate these cells as "Don't Care" symbols (step 6). For "Don't Care" symbol, no EVM will be calculated in the R&S FS-K96 Software.
The R&S FS-K96 Configuration File Wizard will now prompt that you have allocated all your cells.
Saving the Configuration File (Step 7)
Click on the "Save" icon. Choose a filename for your configuration file and save your file. If you have started the R&S FS-K96 Configuration File Wizard directly from the R&S FS-K96 Software, the software will ask you whether you want to immediately import your newly generated configuration file into the R&S FS-K96 Software. The R&S FS-K96 Software will then do an automatic refresh.
Boosting
In the case that you do not find a constellation marker type that matches the constella­tion points (step 5), you may try to use the boosting slider to scale the constellation markers or manually enter the boosting factor of the constellation by double-clicking on the boosting value.
System Configuration File
XML Configuration File Format
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Selecting cells with the mouse
You can manually select cells with the mouse. Press the Ctrl-key to add further cells to the selection.
Selecting cells with the mouse is not only useful for the allocation of "Don't Care" sym­bols (cf. Step 5 and 6 in the Quick Start Guide). You can also use the mouse to select cells and later allocate them as "Data Symbols" or "Pilot Symbols". Then, the current modulation type and boosting factor will be stored for these cells.
Example: Clicking on the "Check" icon will allocate only the highlighted cells as 45°­QPSK pilot symbols with boosting factor 1.
System Configuration File
XML Configuration File Format

5.2.2 Generate I/Q Data Files

The following part describes how to generate *.iqw-files (data format of R&S Signal Analyzers) and *.wv-files (data format for arbitrary waveform generator of R&S Signal Generators). With this description the user obtains a complete R&S test solution for signal generation and analysis of generic OFDM signals.
The R&S FS-K96 Configuration File Wizard offers the possibility to generate an ideal OFDM signal based on a loaded xml configuration file or based on the allocation of a loaded input signal.
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Start the signal generation over the file menu and choose "Generate Test Signal".
Figure 5-10: File Menu of the R&S FS-K96 Configuration File Wizard
For an example WLAN signal, the dialog could then look like displayed in Figure 5-11.
System Configuration File
XML Configuration File Format
Figure 5-11: Signal Generation Dialog of the R&S FS-K96 Configuration File Wizard
In the dialog, contains the following parameters for the generation of bursted signals:
Number of Bursts: Specifies how many bursts are to be generated for the I/Q data file. The file always starts with the ramp of the first burst.
Gap Length: Specifies how many idle symbols are supposed to be between adjacent bursts.
Burst Length: Specifies the length of one single burst. If the burst length is set to automatic, it will coincide with the length of one frame in the configuration file. If the burst length is shorter than the frame length, the last symbols of the frame will be
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ignored for signal generation. If the burst length is to be larger then the frame length, it is recommended to specify a so-called repetition range.
Repetition Range: The repetition range can only be set if the burst length is larger than the specified frame length. In this case, the signal to be generated contains more data symbols then specified in the configuration file. If the repetition range is set to automatic, it will start with the first data symbol and end with the last symbol of the frame. This functionality is especially important for signals that start with a preamble, e.g. WLAN. Please refer to Figure 5-12 and Figure 5-13 for an example.
Figure 5-12: Original Signal
System Configuration File
XML Configuration File Format
Figure 5-13: Signal to Be Generated (Burst Length is 13 symbols)
For a continuous signal, only one parameter needs to be set.
Number of Frames: Specifies the number of OFDM frames that are to be generated. The signal always starts with the first symbol of one frame.
Both, bursted and continuous signals require that the data source is specified.
Data Source: Can be set to "Random" or "As Loaded". If it is set to "Random", new random data is loaded for the data symbols, if refresh is clicked. If it is set to "As Loa­ded", the signal generation function maintains the data symbols that have been initially loaded. These data symbols can come from an original signal that has been loaded into the R&S FS-K96 Configuration File Generator and where all the cells have been allocated.
Use the "Save Signal" button to generate the OFDM signal and save it to file. Be aware that the I/Q data is stored with an oversampling of one. In the case you want to play the signal with an R&S Signal Generator, it is recommended to upsample it in Matlab. Please refer to Chapter 5.1.2.2, "I/Q data files for R&S Signal Generators (*.wv-file) –
mat2wv.m", on page 83 for details on the required I/Q data format.
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6 Measurements in Detail

This section provides a detailed explanation of the measurements provided by the OFDM-VSA and provides help to measure the characteristics of specific types of DUT.
● General Information on Signal Types......................................................................96
● Signal Processing................................................................................................. 105
● Measurement Result Definitions........................................................................... 110
Measurements in Detail
General Information on Signal Types

6.1 General Information on Signal Types

● OFDM......................................................................................................................96
● GFDM....................................................................................................................103
● UFMC....................................................................................................................104

6.1.1 OFDM

● OFDMA................................................................................................................... 96
● OFDM Parameterization......................................................................................... 98
6.1.1.1 OFDMA
In an OFDM system, the available spectrum is divided into multiple carriers, called sub­carriers, which are orthogonal to each other. Each of these subcarriers is independ­ently modulated by a low rate data stream.
OFDM is used as well in WLAN, WiMAX and broadcast technologies like DVB. OFDM has several benefits including its robustness against multipath fading and its efficient receiver architecture.
Figure 6-1 shows a representation of an OFDM signal taken from 3GPP TR 25.892.
Data symbols are independently modulated and transmitted over a high number of closely spaced orthogonal subcarriers. In the OFDM-VSA common modulation schemes as QPSK, 16QAM, and 64QAM can be defined as well as arbitrary distrib­uted constellation points.
In the time domain, a guard interval may be added to each symbol to combat inter­OFDM-symbol-interference due to channel delay spread. In EUTRA, the guard interval is a cyclic prefix which is inserted prior to each OFDM symbol.
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Figure 6-1: Frequency-Time Representation of an OFDM Signal
In practice, the OFDM signal can be generated using the inverse fast Fourier transform (IFFT) digital signal processing. The IFFT converts a number N of complex data sym­bols used as frequency domain bins into the time domain signal. Such an N-point IFFT is illustrated in Figure 6-2, where a(mN+n) refers to the nth subchannel modulated data symbol, during the time period mTu < t ≤ (m+1)Tu.
Measurements in Detail
General Information on Signal Types
Figure 6-2: OFDM useful symbol generation using an IFFT
The vector sm is defined as the useful OFDM symbol. It is the time superposition of the N narrowband modulated subcarriers. Therefore, from a parallel stream of N sources
of data, each one independently modulated, a waveform composed of N orthogonal subcarriers is obtained, with each subcarrier having the shape of a frequency sinc function (see Figure 6-1).
Figure 6-3 illustrates the mapping from a serial stream of QAM symbols to N parallel
streams, used as frequency domain bins for the IFFT. The N-point time domain blocks obtained from the IFFT are then serialized to create a time domain signal. Not shown in Figure 6-3 is the process of cyclic prefix insertion.
Figure 6-3: OFDM Signal Generation Chain
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2
FFT
N
 
 
1
2
,
2
FFTFFT
NN
1
2
FFT
N
 
 
2
1
,
2
1
FFTFFT
NN
Measurements in Detail
General Information on Signal Types
6.1.1.2 OFDM Parameterization
A generic OFDM analyzer supports various OFDM standards. Therefore a common parameterization of OFDM systems has to be defined.
Time Domain Description
The fundamental unit of an OFDM signal in time domain is a 'Sample'. An 'OFDM-Sym­bol' with a length of NS samples consists of a 'Guard Interval' of length NG and an 'FFT
Interval' of length N
N
G
Figure 6-4: OFDM Symbol in Time Domain
Frequency Domain Description
The FFT intervals of the OFDM symbols are transformed into the frequency domain using a discrete Fourier transform. The successive symbols of the OFDM signal are displayed in time-frequency matrices. The fundamental unit of an OFDM signal in fre­quency domain is a 'Cell'. A column of cells at the same frequency is called 'Carrier'. A row of cells at the same time is called 'Symbol'. The carrier number is the column index of a time-frequency matrix. The number '0' is assigned to the so called 'DC-Carrier', which lies at the transmitter center frequency. The total number of carriers is N
'DC-Carrier Offset' determines the position of the DC carrier relative to the lowermost carrier and is an inherent attribute of the FFT algorithm.
FFT
.
N
N
FFT
S
. The
FFT
FFT Length N
even
odd
The symbol number is the row index of a time frequency matrix. The first symbol gets the number '0'. The total area of a time frequency matrix is called 'Frame'. A frame is the highest level unit used in the OFDM-VSA.
FFT
DC-Carrier Offset Range
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