R&S®FSQ-K91, -K91n and -K91ac
WLAN Application Firmware
1157.3135.42 – 08
Test & Measurement
Operating Manual
Operating Manual
The Operating Manual describes the following and firmware applications
®
● R&S
● R&S
● R&S
FSQ-K91 (1157.3129.02)
®
FSQ-K91n (1308.9387.02)
®
FSQ-K91ac (1308.9170.02)
The contents are applicable to the following instruments.
®
● R&S
FSQ (1313.9100.xx)
The contents of this manual correspond to firmware version 4.75SP5 and higher.
© 2014 Rohde & Schwarz GmbH & Co. KG
Muehldorfstr. 15, 81671 Munich. Germany
Phone: +49 89 4129-0
Fax: +49 89 4129-12 164
E-mail: info@rohde-schwarz.com
Internet: http://www.rohde-schwarz.com
81671 Munich, Germany
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
FSQ-K91 is abbreviated as R&S FSQ-K91.
R&S FSQ-K90/K91/K91n Table of Contents
Table of Contents
1 Introduction ............................................................... 5
1.1 Introduction to IEEE 802.11 Tests .............................................. 6
1.2 Installation ................................................................................... 7
1.3 Starting the Application ............................................................. 9
1.4 Exiting the Application ............................................................... 9
1.5 Quick Start Guide........................................................................ 10
1.5.1 Performing a Single Carrier Measurement ................................... 10
1.5.2 Performing a MIMO Measurement ............................................... 12
1.6 Navigation .................................................................................... 18
1.6.1 Hotkeys ......................................................................................... 18
1.6.2 Softkeys ........................................................................................ 20
1.6.3 Hardkeys ....................................................................................... 21
1.6.4 External Keyboard ........................................................................ 22
1.6.5 Mouse ........................................................................................... 23
1.6.6 Selecting and Editing Parameters ................................................ 24
1.6.7 Status Bar and Title Bar ................................................................ 29
1.7 Saving and Recalling Data ......................................................... 30
1.8 Printing ........................................................................................ 31
2 Measurements and Result Displays ........................ 32
2.1 Performing Measurements ........................................................ 32
2.2 Measurements ............................................................................. 33
2.2.1 I/Q Measurements ........................................................................ 33
2.2.2 Frequency Sweep Measurements ................................................ 56
2.3 Measurement Results ................................................................. 63
2.3.1 Result Summary ........................................................................... 65
2.3.2 Limit Values in the Result Summary ............................................. 70
3 Configuration ............................................................ 72
3.1 General Settings ......................................................................... 72
3.1.1 Signal Characteristics ................................................................... 73
Software Manual 1157.3135.42 - 08 1
R&S FSQ-K90/K91/K91n Table of Contents
3.1.2 Level Settings ............................................................................... 75
3.1.3 Data Capture Settings .................................................................. 78
3.1.4 Trigger Settings ............................................................................. 80
3.1.5 I/Q Settings ................................................................................... 83
3.1.6 Input Settings ................................................................................ 83
3.2 STC / MIMO Settings ................................................................... 84
3.2.1 DUT MIMO Configuration ............................................................. 84
3.2.2 MIMO Antenna Signal Capture ..................................................... 85
3.3 Advanced Settings...................................................................... 89
3.3.1 Advanced Baseband Settings ....................................................... 90
3.3.2 Advanced Level Settings .............................................................. 95
3.3.3 Peak Vector Error (IEEE) (IEEE 802.11b & g only) ...................... 99
3.4 Demod Settings ........................................................................... 100
3.4.1 Burst To Analyze Settings ............................................................ 101
3.4.2 Tracking Settings .......................................................................... 109
3.4.3 Synchronisation Settings .............................................................. 111
3.4.4 Filter Settings (IEEE 802.11b & g) ................................................ 112
3.5 Advanced Demod Settings (IEEE 802.11n (MIMO)) ................. 114
3.5.1 Bursts to Analyze (Advanced) ...................................................... 115
3.5.2 Synchronization ............................................................................ 118
3.6 Advanced Demod Settings (IEEE 802.11ac) ............................ 119
3.6.1 PPDU to Analyze (Advanced) ....................................................... 120
3.6.2 Synchronization ............................................................................ 123
3.7 MIMO Settings (IEEE 802.11n (MIMO), ac) ................................ 124
3.7.1 Spatial Mapping Configuration ...................................................... 125
3.7.2 User Defined Spatial Mapping ...................................................... 126
3.8 Gate Settings ............................................................................... 127
3.8.1 Gating (On Off) ............................................................................. 127
3.8.2 Gate Configuration ........................................................................ 128
3.9 Import and Export of I/Q Data .................................................... 130
3.10 Support ........................................................................................ 131
3.11 Markers ........................................................................................ 132
3.12 Display Settings .......................................................................... 134
Software Manual 1157.3135.42 - 08 2
R&S FSQ-K90/K91/K91n Table of Contents
4 Measurement Basics ................................................ 135
4.1 Signal Processing for Multicarrier Measurements (IEEE802.11a, g (OFDM)) ....135
4.1.1 Abbreviations ................................................................................ 135
4.1.2 Literature ....................................................................................... 140
4.2 Signal Processing for Single-Carrier Measurements (IEEE 802.11b, g (DSSS))141
4.2.1 Abbreviations ................................................................................ 141
4.2.2 Literature ....................................................................................... 145
4.3 Signal Processing for MIMO Measurements ............................ 146
4.3.1 Space-Time Block Coding (STBC) ............................................... 146
4.3.2 Spatial Mapping ............................................................................ 147
4.3.3 Physical vs Effective Channels ..................................................... 147
4.3.4 Capturing Data from MIMO Antennas .......................................... 149
4.3.5 Calculating Results ....................................................................... 151
4.4 IEEE 802.11b RF Carrier Suppression ...................................... 153
4.4.1 Definition ....................................................................................... 153
4.4.2 Measurement with Rohde & Schwarz Spectrum Analyzers. ........ 153
4.4.3 Comparison to I/Q Offset Measurement in the WLAN List Mode . 154
4.5 I/Q Impairments ........................................................................... 155
4.5.1 I/Q Offset ....................................................................................... 155
4.5.2 Gain Imbalance ............................................................................. 156
4.5.3 Quadrature Error ........................................................................... 157
4.6 Peak EVM (IEEE) ......................................................................... 158
4.7 Burst EVM (Direct) ...................................................................... 158
5 Remote Control ......................................................... 159
5.1 Description of commands .......................................................... 159
5.1.1 Notation ......................................................................................... 159
5.2 ABORt Subsystem ...................................................................... 162
5.3 CALCulate Subsystem ............................................................... 163
5.3.1 CALCulate:BURSt Subsystem ...................................................... 163
5.3.2 CALCulate:LIMit Subsystem ......................................................... 164
5.3.3 CALCulate:MARKer Subsystem ................................................... 179
5.3.4 CALCulate:MARKer:FUNCtion Subsystem .................................. 185
Software Manual 1157.3135.42 - 08 3
5.4 CONFigure Subsystem ............................................................... 188
R&S FSQ-K90/K91/K91n Table of Contents
5.5 DISPlay Subsystem .................................................................... 213
5.6 FETCh Subsystem ...................................................................... 217
5.7 FORMat Subsystem .................................................................... 229
5.8 INITiate Subsystem ..................................................................... 230
5.9 INPut Subsystem ........................................................................ 231
5.10 INSTrument Subsystem ............................................................. 237
5.11 MMEMory Subsystem ................................................................. 238
5.12 SENSe Subsystem ...................................................................... 240
5.13 STATus Subsystem .................................................................... 265
5.14 TRACe Subsystem ...................................................................... 273
5.14.1 Using the TRACe:DATA Command .............................................. 273
5.14.2 TRACe:IQ Subsystem .................................................................. 282
5.15 TRIGger Subsystem ................................................................... 284
5.16 UNIT Subsystem ......................................................................... 287
5.17 Status reporting registers .......................................................... 289
5.17.1 Description of the Status Registers .............................................. 291
5.18 Error Reporting ........................................................................... 297
5.19 Softkeys with assignment of IEC/IEEE bus commands ......... 298
5.19.1 Key MEAS or Hotkey WLAN ......................................................... 298
5.19.2 Key DISP ...................................................................................... 301
5.19.3 Key MKR ....................................................................................... 301
5.19.4 Key MKR->.................................................................................... 301
5.19.5 Key LINES .................................................................................... 302
5.19.6 Hotkeys ......................................................................................... 302
6 Remote Control - Programming Examples ............. 303
6.1 Synchronization of Entry of Option .......................................... 303
6.2 Selecting Measurements ............................................................ 304
6.3 Running Synchronized Measurements .................................... 305
7 Warnings & Error Messages .................................... 306
Software Manual 1157.3135.42 - 08 4
R&S FSQ-K90/K91/K91n/K91ac Introduction
Introduction to IEEE 802.11 Tests
1 Introduction
The applications R&S FSQ-K91, -K91n and -K91ac (in the following abbreviated as
"WLAN applications") extend the functionality of the R&S FSQ spectrum analyzer to
enable Wireless LAN Tx measurements in accordance with IEEE standards IEEE
802.11a/b/g/j (R&S FSQ-K91), IEEE 802.11n (R&S FSQ-K91n) and IEEE 802.11ac
(R&S FSQ-K91ac).
This manual describes how to use the WLAN applications. It contains instructions on
how to prepare, execute and evaluate measurements and also contains many helpful
hints and examples.
● Chapter "Introduction" (page 5) contains basic information about the WLAN
application, including a "Quick Start Guide" that describes a basic WLAN
measurement.
● Chapter "Measurements and Result Displays" (page 32) contains extensive
information about the measurements and result displays that the WLAN application
provides.
● Chapter "Configuration" (page 72) contains extensive information about
measurement configuration and the parameters that the application provides.
● Chapter "Measurement Basics" (page 135) contains background information about
the featured measurements.
● Chapter "Remote Control" (page 159) contains all remote control commands
supported by the WLAN application.
● Chapter "Remote Control - Programming Examples" (page 303) contains
programming examples for remote control operation of the application.
● Chapter "Warnings & Error Messages" (page 306) contains a list of possible
warnings and error messages that may occur during measurements.
Software Manual 1157.3135.42 - 08 5
R&S FSQ-K90/K91/K91n/K91ac Introduction
Introduction to IEEE 802.11 Tests
1.1 Introduction to IEEE 802.11 Tests
The R&S FSQ-K91 WLAN application extends the functionality of the R&S FSQ to
enable accurate and reproducible Tx measurements of a WLAN device under test
(DUT) in accordance with the standards specified for the device.
The following standards are currently supported (if the corresponding firmware option
is installed):
● IEEE 802.11a
● IEEE 802.11b
● IEEE 802.11g (OFDM)
● IEEE 802.11g (DSSS)
● IEEE 802.11j
● IEEE 802.11n (SISO) (with option R&S FSQ-K91n)
● IEEE 802.11n (MIMO) (with option R&S FSQ-K91n)
● IEEE 802.11 ac (with option R&S FSQ-K91ac)
● IEEE 802.11 OFDM Turbo Mode
Features
● Modulation measurements
- Constellation diagram
- Constellation diagram for each OFDM carrier
- I/Q offset and I/Q imbalance
- Carrier and symbol frequency errors
- Modulation error (EVM) for each OFDM carrier or symbol
- Amplitude response and group-delay distortion (spectral flatness)
● Amplitude statistics (CCDF) and crest factor
● Transmit spectrum mask
● FFT, also over a selected part of the signal, e.g. preamble
● Payload bit information
● Capture time selectable up to 100 ms (depending on selected standard), multiple
sweeps possible for large number of PPDUs
● Freq/Phase Err vs. Preamble
Software Manual 1157.3135.42 - 08 6
R&S FSQ-K90/K91/K91n/K91ac Introduction
Installation
1.2 Installation
Installing the software
To get the full functionality of the WLAN application described in this document, make
sure to install the latest firmware. The latest firmware is available for download on the
R&S FSQ homepage at http://www.rohde-schwarz.com/product/fsq.html.
To perform a firmware update, proceed as follows.
1. Copy the downloaded data to a memory stick or similar USB device and connect it
to the R&S FSQ.
2. Press the SETUP key.
3. Press the NEXT key.
4. Press the "Firmware Update" softkey.
5. In the submenu, again press the "Firmware Update"s oftkey.
6. Follow the instructions as displayed on the screen.
When the installation is done, the analyzer will reboot.
Also refer to the documentation of the R&S FSQ for more comprehensive instructions
on how to perform firmware updates.
Activating the firmware option
Once the option has been installed, it needs to be activated with an option key.
1. Press the SETUP key
2. Press the "General Setup" softkey
3. Press the "Options" softkey.
The R&S FSQ displays a list of currently active firmware applications.
4. Press the "Install Option" softkey.
The R&S FSQ opens a dialog box to enter the option key.
Software Manual 1157.3135.42 - 08 7
R&S FSQ-K90/K91/K91n/K91ac Introduction
Installation
5. Enter the option key supplied with the WLAN application.
If you are upgrading from an older version of the WLAN application (for example
from the R&S FSQ-K90 to R&S FSQ-K91 or R&S FSQ-K91n), enter the upgrade
key in addition to the original R&S FSQ-K90 option key.
An additional key is also required for IEEE 802.11n and IEEE 802.11ac support.
If the option key you have entered is valid, you have to reboot the R&S FSQ. The
R&S FSQ displays a corresponding message box.
6. Press "OK" in the message box to reboot the R&S FSQ.
When the R&S FSQ has rebooted, it displays a new hotkey at the bottom of the
display labeled "WLAN". In addition, the "Firmware Options" dialog box contains an
entry for the WLAN application(s).
Software Manual 1157.3135.42 - 08 8
R&S FSQ-K90/K91/K91n/K91ac Introduction
Starting the Application
1.3 Starting the Application
► Turn on the R&S FSQ.
If the WLAN application has been installed correctly, the hotkey bar at the bottom
of the screen should contain a hotkey labeled "WLAN".
► Press the "WLAN" hotkey to start the WLAN application.
If you turn off the R&S FSQ while the WLAN application is active, the R&S FSQ will
start up in the WLAN application when you turn it on again.
1.4 Exiting the Application
► To exit the WLAN application, press the "SPECTRUM" hotkey.
The R&S FSQ closes the WLAN application and enters Spectrum mode. The settings
that were active before you started the WLAN application are restored.
Software Manual 1157.3135.42 - 08 9
R&S FSQ-K90/K91/K91n/K91ac Introduction
DUT
RF Input
(front panel)
Quick Start Guide
1.5 Quick Start Guide
The Quick Start Guide helps you to become familiar with the WLAN application. It
contains a basic single carrier WLAN measurement and a basic MIMO measurement.
Both measurements use a basic configuration that allows you to perform the
measurements quickly and efficiently.
1.5.1 Performing a Single Carrier Measurement
The DUT in this example generates an IEEE 802.11a signal with a 16QAM modulation.
Measurement setup
► Connect the DUT tot he RF input on the front panel of the R&S FSQ.
Preparing the measurement
1. Start the WLAN application.
2. Press the "General Settings" softkey
The R&S FSQ opens the "General Settings" dialog box.
3. Select the the IEEE 802.11a standard from the "Standard" dropdown menu.
4. Select the "Frequency" field and enter the required measurement frequency.
If you enter a valid frequency, the application updates the "Channel No" field
(→ "Signal Characteristics").
Note that you can also access the "Frequency" field directly by pressing the FREQ
key.
5. Make sure to turn on auto leveling by adding the checkmark in the "Auto" field
(→ "Level Settings") to enable automatic level detection.
If auto leveling is on, the WLAN application automatically determines the ideal
reference level prior to each measurement.
Alternatively, you can start a measurement to determine the ideal reference level
with the AUTO LVL hotkey.
All other settings in the "General Settings" dialog box are sufficient for this example.
Software Manual 1157.3135.42 - 08 10
R&S FSQ-K90/K91/K91n/K91ac Introduction
Quick Start Guide
6. Press the "Demod Settings" softkey.
The R&S FSQ opens the "Demod Settings" dialog box.
7. Select the modulation scheme in the "Demodulator" field.
8. Close the "Demod Settings" dialog box with the WLAN hotkey.
Performing the Measurement
1. Press the RUN SGL hotkey to start the measurement.
2. During the measurement, the text "Running..." is displayed in the status bar at the
bottom of the screen.
Measurement results are updated once the measurement has been completed. The
results are displayed in graphical form. The display can be toggled to a tabular list of
measurement results by pressing the DISPLAY softkey.
Software Manual 1157.3135.42 - 08 11
R&S FSQ-K90/K91/K91n/K91ac Introduction
Two
Channel
SMU
FSx
FSx
LAN
Hub
Trigger Signal
Reference Signal
RF Signal
LAN
LAN
LAN
1
Tx
2
Tx
1
Rx
2
Rx
Quick Start Guide
1.5.2 Performing a MIMO Measurement
The DUT, in this case an R&S SMU, generates an IEEE 802.11n signal. The
R&S SMU simulates a MIMO DUT with two transmission antennas.
The R&S SMU has to be equipped with two RF paths and the corresponding option for
WLAN signal generation (R&S SMU-K54 for IEEE 802.11n signals).
To test both antennas simultaneously, two signal analyzers are required. However,
only one analyzer needs to be equipped with the WLAN application.
Measurement setup
► Connect the DUT and analyzers as illustrated below.
► Connect the two analyzers to each other directly with a cross LAN cable or
integrate them both in a LAN. The analyzer with the WLAN application (master)
controls the second analyzer (slave) by providing the trigger signal to start the
measurement.
► Connect the external reference REF OUT of the R&S SMU to the external
reference REF IN of the analyzers.
Turn on the external reference for both analyzers in the spectrum analyzer base
system.
► Connect the marker output of the R&S SMU to the Ext Trigger input of the
analyzers.
► Establish a connection between the signal generator and the analyzers.
- Connect the Path A RF / Baseband connector directly to the first analyzer, and
the Path B RF / Baseband connector directly to the second analyzer.
or
- Use the air interface with appropriate antennas.
Software Manual 1157.3135.42 - 08 12
R&S FSQ-K90/K91/K91n/K91ac Introduction
Quick Start Guide
Configuring the signal generator
Basically, it is sufficient to configure one Baseband and then configure the second
Baseband from the first.
1. Select the signal path for "Baseband A".
2. Select the "IEEE 802.11n…" option to configure a WLAN signal.
The R&S SMU opens the "IEEE 802.11n WLAN A" dialog box.
3. Select a "Transmission Bandwidth" of 40 MHz.
4. Press the "Transmit Antennas Setup…" button.
The R&S SMU opens the "IEEE 802.11n WLAN A: Tx Antenna Setup" dialog box.
5. Select 2 antennas from the "Antennas" dropdown menu.
6. Return to the "IEEE 802.11n WLAN A" dialog box.
Software Manual 1157.3135.42 - 08 13
R&S FSQ-K90/K91/K91n/K91ac Introduction
Quick Start Guide
7. Press the "Frame Block Configuration…" button.
The R&S SMU opens the "IEEE 802.11n WLAN A Frame Blocks Configuration"
dialog box.
8. Select HT-40MHz from the "Tx Mode" dropdown menu.
9. Press the "PPDU Config…" button.
The R&S SMU opens the "IEEE 802.11n WLAN A: PPDU Configuration for Frame
Block 1" dialog box.
10. Select two "Spatial Streams" and two "Space Time Streams".
Software Manual 1157.3135.42 - 08 14
R&S FSQ-K90/K91/K91n/K91ac Introduction
Quick Start Guide
11. Return to the "IEEE 802.11n WLAN A" dialog box.
12. Select "Configure Baseband B from Baseband A".
The R&S SMU transfers the configuration of Path A to Baseband Path B. Thus,
Baseband Path B also generates an IEEE 802.11n signal.
13. Press the "State" button to turn on the signal.
Make also sure that both signal paths (RF/A Mod A and RF/B Mod B) are turned
on.
14. Turn on the Graphics | Power Spectrum display.
These displays show the power spectrum for both antennas.
Software Manual 1157.3135.42 - 08 15
R&S FSQ-K90/K91/K91n/K91ac Introduction
Quick Start Guide
Configuring the spectrum analyzer
After configuring the signal generator, configure the spectrum analyzer.
1. Start the WLAN application.
2. Press the "General Settings" softkey to open the "General Settings" dialog.
3. Select "IEEE 802.11n (MIMO)" from the "Standard" dropdown menu.
4. Define the RF Frequency the DUT is transmitting in the "Frequency" field.
5. Select the external "Trigger Mode".
6. Select the "STC/MIMO" tab with the left and right cursor keys.
Changing the tabs is possible when the cursor (blue background) is positioned on
the tab label. You can position the cursor with the up and down cursor keys, for
example.
7. Select "2 Tx Antennas" from the "DUT MIMO Configuration" dropdown menu.
Software Manual 1157.3135.42 - 08 16
R&S FSQ-K90/K91/K91n/K91ac Introduction
Quick Start Guide
8. Enter the IP Address of the second signal analyzer in the "MIMO Measurement
Setup" table.
9. Turn on the second analyzer in the "State" column.
10. Press the RUN SGL or RUN CONT hotkey.
The application starts the measurement and shows the results.
Software Manual 1157.3135.42 - 08 17
R&S FSQ-K90/K91/K91n/K91ac Introduction
The SPECTRUM hotkey exits the WLAN application and returns to Spectrum mode
The WLAN hotkey restores the main measurement menu of the WLAN application. All
The AUTO LVL hotkey starts an automatic level detection measurement.
Navigation
1.6 Navigation
This section describes the navigation within the option. Navigation in this context
means all forms of interaction with the option except for remote control. The different
methods of interacting with the option are:
● Hotkeys
● Softkeys
● Hardkeys
● Numeric keypad
● Rotary knob
● Cursor keys
● External keyboard
● Mouse
1.6.1 Hotkeys
Hotkeys are allocated to the seven keys at the bottom edge of the screen. On initial
startup of the WLAN application, the hotkeys provided are shown in Fig. 1. These
hotkeys are present at all times after the option has been started.
Fig. 1 Initial hotkey menu
Pressing one of the hotkeys activates the associated hotkey. When active, the color of
the hotkey turns green.
The hotkeys perform the following operations:
with all previous settings restored.
settings and dialog boxes are removed from the display, and the default softkey menu
is displayed.
The WLAN hotkey remains green as long as the WLAN application is active.
If another measurement is running, it will be aborted before the automatic level
detection measurement is started. If a continuous measurement is running when the
AUTO LVL hotkey is pressed, the continuous measurement will resume after the
automatic level detection has been completed.
Pressing the AUTO LVL hotkey while an automatic level detection measurement is
running causes the measurement to be stopped immediately.
Software Manual 1157.3135.42 - 08 18
R&S FSQ-K90/K91/K91n/K91ac Introduction
The RUN SGL hotkey initiates a single measurement.
The RUN CONT hotkey initiates a continuous measurement.
The REFRESH hotkey updates the current measurement results to reflect the current
The SCREEN [A|B] hotkey selects the specified screen as the active screen.
Navigation
● Pressing RUN SGL while a single sweep measurement is running causes the
application to stop the measurement.
● Pressing RUN SGL while a continuous measurement is running causes the
application to abort that measurement before it initiates the single measurement.
Pressing RUN CONT while a continuous measurement is running causes the
application to stop the measurement.
Pressing RUN CONT while a single measurement is running causes the application to
abort that measurement before it initiates the continuous measurement.
measurement settings.
The REFRESH hotkey is available for all I/Q measurements. The REFRESH hotkey is
available only when I/Q data is available.
In full screen mode, pressing the SCREEN [A|B] hotkey displays the specified screen.
Pressing the SCREEN [A|B] hotkey changes the label displayed in the hotkey, for
example, pressing SCREEN A changes the label of the hotkey to SCREEN B. The
label indicates which screen will become the active screen after the hotkey is pressed.
Note that in case of MIMO measurements with several windows in the result displays,
this hotkey is labeled SCREEN…
Software Manual 1157.3135.42 - 08 19
R&S FSQ-K90/K91/K91n/K91ac Introduction
General Settings
Demod Settings
Softkey
Label
1
Softkey
Label 2
Softkey
Label 3
Softkey
Label 4
Softkey 5
Val 1 Val 2
Softkey available
(normal state)
Softkey is active
Softkey is active and a
dialog box is open
Softkey function is
unavailable (no
3D frame)
Softkey has a toggle function
(selected function is green)
Navigation
1.6.2 Softkeys
1.6.2.1 Settings Softkeys
The softkeys are assigned to the nine keys on the right-hand side of the display. These
enable quick access to all settings and measurement screens of the WLAN application.
The two softkeys at the top ("General Settings" and "Demod Settings") are always
available (except when you are using the save / Recall, print or markers functionality).
They open the corresponding dialog boxes whose features are described in
"Measurements and Result Displays" on page 32.
Configures signal characteristics, data capture, trigger functionality and I/Q settings.
Configures the type of PPDU to measure.
1.6.2.2 Other Softkeys
All other softkeys have different functions depending on the instrument state.
Therefore, the labels (text) on the softkeys vary to reflect their current function. The
state of the softkeys is indicated by different appearances and colors, as follows:
● When the function of a softkey is available, it is colored grey with a 3D border.
● When the function of a softkey is active, it is colored green with a 3D border.
● When the function of a softkey is active and a dialog box is displayed, it is colored
red with a 3D border.
● When the function of a softkey is unavailable, it is colored grey without a 3D
border. This may be the case if the function is not supported by the current
configuration.
● When a softkey has several functions (toggle functionality), you can access the
different functions by repeatedly pressing the softkey. The currently active function
is colored green.
● When a softkey has no function, the application shows no label for that softkey.
Software Manual 1157.3135.42 - 08 20
R&S FSQ-K90/K91/K91n/K91ac Introduction
FREQ
Opens the "General Settings" dialog box and selects the "Frequency"
MKR
Opens the Marker menu to configure markers.
SWEEP
Opens the "General Settings" dialog box and selects the "Capture
MEAS
Opens the Measurement menu to configure and select measurements.
TRACE
Opens the "General Settings" menu and selects the "Burst Count"
LINES
Allows you to define limits for numerical results.
FILE
Opens the file manager to save and restore measurement results and
HCOPY
Opens a menu to configure the printer.
Navigation
1.6.3 Hardkeys
Hardkeys allow quick access to a particular parameter and various functions. The
WLAN application supports the following hardkeys.
parameter for quick definition of the measurement frequency.
AMPT Opens the "General Settings" dialog box and selects the "Signal Level"
parameter for quick definition of the expected signal level.
MKR→ Opens the Marker To menu to position markers.
Time" parameter for quick definition of the measurement time.
parameter for quick definition of the PPDU count.
Available for the numerical Result Summary.
DISP Opens the Display menu to configure the display.
configuration.
PRESET Exits the WLAN application and restores the default configuration of the
R&S FSQ.
Software Manual 1157.3135.42 - 08 21
R&S FSQ-K90/K91/K91n/K91ac Introduction
Number keys
Allows you to enter any kind of number.
Decimal point
Inserts a decimal point "." at the cursor position.
Minus key
If you are using it with numbers, the minus key changes the sign of
ESC key
Aborts the entry before it has been terminated. The previous value
ENTER key
Terminates the input of dimension quantities. The new value is set.
Left and Right
Navigates between individual parameters within dialog boxes.
Up and Down
Navigates between individual parameters within the setting views
CTRL-F1 CTRL-F
2 CTRL-F3 CTRL-F
4 CTRL-F5 CTRL-F
6 CTRL-F7
Navigation
1.6.4 External Keyboard
The WLAN application allows you to control it with an external keyboard. It supports
the following keys to interact with the application.
(0 to 9)
(".")
("-")
Cursor
Cursor
the mantissa or the exponent of that number.
If you are using it with alphanumeric characters, the minus key
writes a dash character.
is restored.
Closes the entry field after termination of input.
Closes dialog boxes.
Activates the input of parameters or immediately sets the new
value.
Selects the highlighted item in dropdown menus.
Navigates between the individual items within dropdown menus.
Moves the cursor left and right inside an entry window to reach a
particular position in a string during alphanumeric entries.
and some of the dialog boxes.
Navigates between the individual items within dropdown menus.
Increments or decrements the numeric value of a parameter.
CTRL keys Controls and selects hotkeys in combination with the function keys.
Each of the seven hotkeys is allocated a different function (F<x>)
key. To access these hotkeys, press CTRL-F<x>.
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R&S FSQ-K90/K91/K91n/K91ac Introduction
Function Keys
Controls and selects softkeys
F1
Softkey 1
F
2
Softkey 2
F
3
Softkey
3
F4
Softkey 4
F
9
...
Softkey 9
Navigation
Each of the nine softkeys is allocated a different function (F<x>)
key. To access these softkeys, F<x>.
1.6.5 Mouse
The WLAN application supports a mouse to select parameters within dialog boxes or
input fields. It also allows you to select hotkeys, softkeys or items from a dropdown
menu with the mouse.
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R&S FSQ-K90/K91/K91n/K91ac Introduction
Navigation
1.6.6 Selecting and Editing Parameters
You can change the values of parameters in different ways.
● Enter numeric or alphanumeric values
● Select an item from a dropdown menu
● Turn something on and off with a check box.
In all cases, the parameter has to be selected by placing focus on it. You can do so by
navigating to the corresponding parameter with the cursor keys or the rotary knob.
The R&S FSQ provides the following methods to edit parameters. (As an alternative,
you can use an external keyboard or mouse)
1.6.6.1 Numeric Keypad
The numeric keypad is provided for entering numeric parameters. It contains the
following keys:
Number keys 0 to 9
The number keys allow you to enter a numeric value into fields that support numeric values.
The number keys also allow you to enter numbers into fields that support alphanumeric values. The number
is entered at the cursor position in that case.
Decimal point (".")
Inserts a decimal point at the cursor position.
Minus sign ("-")
The minus key changes the sign of the mantissa or the exponent of that number, if you use it in a field that
supports numeric values.
If you are using it with alphanumeric characters, the minus key writes a dash character.
Unit keys (GHz/-dBm, MHz/dBm, kHz/dB and Hz/dB)
Provides the numeric value entered with the selected unit and sets the parameter to that value.
The unit keys are all assigned the value "1" for dimensionless quantities or for level entries (e.g. in dB). The
unit keys thus assume the function of an ENTER key.
BACK key
Deletes the character to the left of the cursor when you are entering alphanumeric values.
ESC/CANCEL key
− Aborts the entry of a new parameter value. The previous value is restored.
− Closes dialog boxes.
ENTER key
− Enables editing of the selected parameter (using numeric keys or rotary knob).
− Finishes the editing of a parameter value. The new value is set.
− For an alphanumeric value, the new value is set to the displayed value (using the current unit if applicable).
− In a drop-down menu, the parameter is set to the currently selected value in the list.
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Navigation
1.6.6.2 Rotary Knob
The rotary knob allows you to perform the following actions.
− In a dialog box, the rotary knob navigates between individual parameters. The currently selected
parameter is highlighted blue.
− In dropdown menus, the rotary knob navigates between the individual values for the parameter.
− While changing a numeric parameter, its value is incremented (by turning clockwise) or decremented (by
turning counterclockwise) at a defined step size (depending on the parameter).
− In dialog boxes, pressing the rotary knob activates the input or selection of values or immediately sets the
new value. Thus, pressing the rotary knob is like pressing the ENTER key.
− In dropdown menus, pressing the rotary knob selects the required item.
1.6.6.3 Cursor Keys
The left ( ) and right ( ) cursor keys are used as follows.
− In a dialog box, the cursor keys navigate between individual parameters. The currently selected parameter
is highlighted blue.
− In dropdown menus, the rotary knob navigates between the individual values for the parameter.
− Moves the cursor inside an entry field left and right to reach a particular position in the string during
alphanumeric entry.
The up (
− In a dialog box, the cursor keys navigate between individual parameters. The currently selected parameter
is highlighted blue.
− In dropdown menus, the rotary knob navigates between the individual values for the parameter.
− Increment or decrement the value of a parameter during numeric entry.
) and down ( ) cursor keys are used as follows.
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R&S FSQ-K90/K91/K91n/K91ac Introduction
Navigation
1.6.6.4 Selecting Parameters in Dialog Boxes
The application allows you to select parameters in different ways.
Selecting the parameter with the rotary knob
1. Open a dialog box (for example the "General Settings").
2. Turn the rotary knob until you reach a particular parameter.
Turning the rotary knob clockwise selects a parameter below the current focus.
Turning it counterclockwise selects a parameter above the current focus.
When a parameter is in focus, its label turns blue.
Press the rotary knob to edit the parameter. In case of numeric parameters, you
can also edit the parameter by entering a numeric value from the numeric keypad
without pressing ENTER first.
Selecting the parameter with the cursor keys
1. Open a dialog box (for example the "General Settings").
2. Press one of the cursor keys until you reach a particular parameter.
Pressing the DOWN or RIGHT cursor keys selects a parameter below the current
focus. Pressing the UP or LEFT cursor keys selects a parameter above the current
focus.
In a table, the cursor keys move the focus in the corresponding direction.
When the focus is on a particular parameter, its label turns blue.
Selection using mouse
1. Move the cursor to a particular parameter
2. Press the left mouse button to put the focus on the parameter.
When the focus is on a particular parameter, its label turns blue.
Press the rotary knob or the ENTER key to edit the parameter. In case of numeric
parameters, you can also edit the parameter by entering a numeric value from the
numeric keypad without pressing ENTER first.
Selection using external keyboard
► Use the cursor keys to select a particular parameter (in the same way as using the
cursor keys on the front panel).
When the focus is on a particular parameter, its label turns blue.
Press the rotary knob or the ENTER key to edit the parameter. In case of numeric
parameters, you can also edit the parameter by entering a numeric value from the
numeric keypad without pressing ENTER first.
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Navigation
1.6.6.5 Entering Numeric Values
The application allows you to enter numeric values in different ways.
1. Select a parameter.
2. Press the rotary knob to edit the parameter.
In case of numeric parameters, you can edit the parameter by entering a numeric
value from the numeric keypad without pressing ENTER first.
If the new value is not valid, a message box is displayed and the value you have
entered is not accepted.
Entering values with the numeric keypad
1. Enter the required value using the number keys.
2. Finish the entry with one of the unit keys or the ENTER key for numbers without a
unit.
Entering values with the cursor keys
1. Press the UP or DOWN cursor keys until you reach the required value.
The application prevents the minimum and maximum values of the parameter from
being exceeded and displays an "Out of range" message box if attempted.
2. Finish the entry with one of the unit keys or the ENTER key for numbers without a
unit.
Changing a numeric value with the cursor has a larger step size compared to
changing a numeric value with the rotary knob.
Each change of the parameter value takes place immediately. No other keys need
to be pressed.
Entering values with the rotary knob
1. Turn the rotary knob until you reach the required value.
Turning the rotary knob clockwise increases the value Turning it counterclockwise
decreases the value.
The application prevents the minimum and maximum values of the parameter from
being exceeded and displays an "Out of range" message box if attempted.
2. Finish the entry with one of the unit keys or the ENTER key for numbers without a
unit.
Changing a numeric value with the cursor has a larger step size compared to
changing a numeric value with the rotary knob.
Each change of the parameter value takes place immediately. No other keys need
to be pressed.
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Navigation
Entering values with an external keyboard
Using an external keyboard works the same way as when you are using the numeric
keypad on the instrument.
Aborting the entry
► Press the ESC key while editing a parameter.
The original value is restored. The new entry is deleted.
1.6.6.6 Selecting Items from a Dropdown Menu
The application allows you to enter numeric values in different ways.
1. Select a parameter.
2. Press the rotary knob to open the dropdown menu.
Selecting items with the cursor keys
1. Press the UP and DOWN cursor keys to select an item in the dropdown menu.
The currently selected value is highlighted blue.
2. Press the ENTER key or the rotary knob to activate the selected value.
Selecting items with the rotary knob
1. Turn the rotary knob until you reach the required item in the dropdown menu.
The currently selected value is highlighted blue.
2. Press rotary knob to activate the selected value.
1.6.6.7 Using Checkboxes
A checkbox turns a parameter on and off (boolean settings).
The application shows a checkmark () in the box when the setting is on. The
checkbox is empty when the setting is off.
The application allows you to use checkboxes in different ways.
Using checkboxes with the rotary knob
► Press the rotary knob to toggle between the two states.
Using checkboxes with the numeric keypad
► Press the ENTER key to toggle between the two states.
Using checkboxes with a mouse
► Left-click on the checkbox to toggle between the two states.
Using checkboxes with an external keyboard
► Press the ENTER key to toggle between the two states.
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R&S FSQ-K90/K91/K91n/K91ac Introduction
MIN:<XX.XX> MAX:<XX.XX>
Navigation
1.6.7 Status Bar and Title Bar
1.6.7.1 Title Bar
The title bar is visible at the very top of the display when the WLAN application is
active and no dialog boxes are displayed.
Fig. 2 Title Bar
The center of the title bar shows the currently selected WLAN standard. If the IEEE
802.11a standard is selected and a sample rate other than the default sample rate is
specified, the sample rate used is displayed on the left-hand side of the title bar.
1.6.7.2 Status Bar
The main status bar is displayed at the bottom of the display, just above the hotkeys.
When a parameter in a settings view is selected, the status bar will display the
minimum and maximum settings for the selected parameter (see Fig. 3).
Fig. 3 Status Bar
When a parameter whose value is enumerated or boolean in type is selected in any
dialog, the status bar will show "N/A" for the minimum and maximum, since the
minimum and maximum values are "Not Applicable."
At other times, the status bar shows the current measurement status along with
detailed information about the progress of any running measurement.
The status bar is also used to display warning and error messages to the user. In order
to highlight these messages, warning messages are displayed with a blue background
and error messages with a red background.
Refer to "Warnings & Error Messages" on page 306 for a list of warning and error
messages.
Software Manual 1157.3135.42 - 08 29
R&S FSQ-K90/K91/K91n/K91ac Introduction
● Current Settings
All user settings provided by the W LAN application.
● User Limits
All limit lines and table limit values.
● IQ Data
Allows the raw I/Q trace results to be stored. When restored,
Saving and Recalling Data
1.7 Saving and Recalling Data
The FILE key opens a softkey menu to manage different types of files that you can use
with the WLAN application.
Note that the application closes all dialog boxes when you start the file manager.
Fig. 4 Save/Recall softkey menu
The save / recall functionality provided by the WLAN application is exactly the same as
that provided in Spectrum mode. Refer to the user manual for the spectrum analyzer
for details about the save / recall functionality.
The save / recall functionality in the WLAN application supports saving and restoring
the following items.
● WLAN Results All current trace and table results.
the data is reprocessed to generate results.
Note: I/Q data can also be saved and restored using the
Import / Export feature for .iqw format files.
► To close the save / recall softkey menu and return to the main softkey menu, press
the WLAN hotkey.
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R&S FSQ-K90/K91/K91n/K91ac Introduction
Printing
1.8 Printing
This section of the user manual describes print functionality of the WLAN application.
The HCOPY key opens the Print softkey menu. Any dialog boxes are closed when you
open the Save / Recall menu.
Fig. 5 Print softkey menu
The print functionality provided by the WLAN application is exactly the same as that
provided in Spectrum mode. Refer to the user manual for the spectrum analyzer for
details about the print functionality.
► To close the print softkey menu and return to the main softkey menu, press the
WLAN hotkey.
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R&S FSQ-K90/K91/K91n/K91ac Measurements and Result Displays
Performing Measurements
2 Measurements and Result Displays
● Performing Measurements (p. 32)
● Measurements (p. 33)
● Measurement Results (p. 63)
2.1 Performing Measurements
To start a measurement, press the RUN SGL hotkey (single) or RUN CONT hotkey
(continuous).
The length of a single measurement or single sweep is defined by the "No of Bursts to
Analyze" or the "Capture Time".
If you perform a continuous measurement, the application runs the measurement in an
endless loop. The measurement only stops if you stop it on purpose. To stop
continuous measurements, either press the RUN CONT hotkey again or start a single
measurement with RUN SGL. If you stop the measurement with RUN CONT, the
current data remains in the capture buffer.
While the measurement runs continuously, the WLAN application averages the data.
If one measurement is started while another measurement is in progress (for example,
a single measurement is started while a continuous measurement is in progress), the
first measurement will be aborted and the new measurement started immediately.
During a measurement, the text "Running..." is displayed in the Status Bar at the
bottom of the screen. After successful completion of a single measurement, the Status
Bar will display "Measurement Complete".
Remote:
INITiate[:IMMediate]
INITiate:CONTinuous <State>
In remote operation it is recommended to perform synchronized single measurements.
Software Manual 1157.3135.42 - 08 32
R&S FSQ-K90/K91/K91n/K91ac Measurements and Result Displays
Measurements
2.2 Measurements
The WLAN application provides two main measurement types:
● I/Q Measurements (see page 33)
● Frequency Sweep Measurements (see page 56)
2.2.1 I/Q Measurements
The following result displays are available in I/Q measurement mode:
● Power vs Time (PVT)
● EVM vs Symbol
● EVM vs Carrier
● Frequency Error vs Preamble
● Phase Error vs Preamble
● Spectrum Flatness and Group Delay
● Spectrum FFT
● Constellation
● Constellation vs Carrier
● Complementary Cumulative Distribution Function
● Bit Stream
● Signal Field
● PLCP Header
Note that all I/Q measurements process the same signal data and, thus, all I/Q
measurement results are available after a single I/Q measurement.
You can use all available input sources for I/Q measurements (RF, analog baseband
and digital baseband).
Software Manual 1157.3135.42 - 08 33
R&S FSQ-K90/K91/K91n/K91ac Measurements and Result Displays
In case of the IEEE 802.11b standard, the Use Signal Field Content parameter is
replaced by
For automatic signal demodulation check
Demodulation
Measurements
2.2.1.1 Capture Buffer
The Capture Buffer result display shows the power characteristics of the signal over
time. The amount of data that is displayed depends on the Capture Time or the No of
Bursts to Analyze.
All analyzed PPDUs are labeled with a green bar at the bottom of the result display.
PPDUs which are analyzed but contain possible errors are labeled by a yellow bar.
In split screen mode, the Capture Buffer is always displayed in Screen A.
If you select the "Use Signal Field Content" parameter in the "Demod Settings" dialog
box, only PPDUs that match the required criteria are marked with a green bar.
Use (PLCP) Header Content parameter.
Use (PLCP) Header Content and Auto
.
Fig. 6 Magnitude Capture Buffer results
Screen size
You can display I/Q measurement results in split screen mode or full screen mode.
Split screen mode allows both the Capture Buffer result display and the selected I/Q
measurement results to be displayed simultaneously. Full screen mode shows either
the Capture Buffer result display or the selected I/Q measurement results.
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R&S FSQ-K90/K91/K91n/K91ac Measurements and Result Displays
Measurements
2.2.1.2 Power vs Time (PVT)
► Press the "PVT" softkey in the main measurement menu to select the Power vs
Time result display.
The PVT result display shows the minimum, average and maximum power of the
PPDUs that have been captured and evaluated or over a complete PPDU in case of a
gated measurement.
The displayed results are calculated over all PPDUs available in the capture buffer.
If you are performing a gated measurement and change the gate settings, you can
update the results with the REFRESH hotkey.
The information in the result display depends on the WLAN standard.
The application allows you display the full PPDU (→ "Full Burst" softkey) or only the
rising and falling edges / ramps of the PPDU (→ "Rising Falling" softkey and "Up
Ramp" and "Down Ramp" softkeys).
● Full Burst
If you display the full burst, the x-axis represents the length of one PPDU and
shows its characteristics without interruption.
Displaying full PPDUs is available for IEEE 802.11a, g (OFDM), j and n.
PvT results for a full PPDU (example based on an IEEE802.11a signal)
● Rising and falling edges
If you display the rising and falling edges, the result display is split into two
diagrams. The first diagram contains the rising edge of the PPDU, the second
diagram the falling edge of the PPDU.
Displaying the rising and falling edges of a PPDU is available for IEEE 802.11a, j,
n, ac and Turbo Mode.
PvT results for the edges only (example based on an IEEE802.11a signal)
Software Manual 1157.3135.42 - 08 35
R&S FSQ-K90/K91/K91n/K91ac Measurements and Result Displays
Measurements
● MIMO measurements
In case of MIMO measurements (IEEE 802.11n and ac), the result display is split
into several smaller ones, each of which contains the information about one
antenna. So, for example, if you have captured the data from two antennas, the
result display would split into two diagrams. The first diagram contains the burst
characteristics of the first antenna, the second diagram those of the second
antenna.
PvT results for the edges only (example based on an IEEE802.11n MIMO signal with 2 antennas)
● Rising and falling ramps
For measurements on IEEE 802.11b and g (Single Carrier) signals, the PvT results
are a percentage of a reference power. You can either display the rising or falling
ramp only, or both (→ "Up Ramp" and "Down Ramp" softkeys).
For both rising and falling edges, two time lines are displayed, which mark the
points 10 % and 90 % of the reference power. The time between these two points
is compared against the limits specified by the IEEE 802.11 standard for the rising
and falling edges.
The reference power is either the maximum or mean power of a PPDU (→ "Ref
Pow (Max Mean)" softkey).
In addition, you can also define the length of a smoothing filter (→ "Average
Length" softkey). For more information on the smoothing filter see "Working with
modulated signals (smoothing filter)".
PvT results for the rising and falling ramps (example based on an IEEE802.11b signal)
Remote:
CONFigure:BURSt:PVT:SELect <Method>
CONFigure:BURSt:PVT:RPOWer <ReferencePower>
CONFigure:BURSt:PVT:AVERage <Samples>
Software Manual 1157.3135.42 - 08 36
R&S FSQ-K90/K91/K91n/K91ac Measurements and Result Displays
max
P
max
PP
ref
=
mean
P
meanref
PP =
ref
P⋅5.0
ref
P⋅1.0
10
t
ref
P⋅9.0
90
t
1090
ttT
Rise
−=
ref
P⋅5.0
ref
P⋅1.0
10
t
ref
P⋅9.0
90
t
9010
ttT
Fall
−=
Measurements
Definition of the rise and fall time
The Rise Time and Fall Time are calculated according to the following algorithm:
1. Apply a smoothing filter across the PPDU power (adjustable average length)
2. If "REF POW" = 'MAX':
Search for maximum power
across the entire PPDU. Set
.
If "REF POW" = 'MEAN':
Calculate mean power
of the entire PPDU. Set
.
3. Rise Time
a. Search for the first crossing of
b. Search backward for the 10 % crossing
c. Search forward for the 90 % crossing
d. Return
.
from the left.
and note
and note
.
.
4. Fall Time
a. Search for the first crossing of
b. Search forward for the 10 % crossing
c. Search backward for the 90 % crossing
d. Return
.
from the right.
and note
and note
.
.
Working with modulated signals (smoothing filter)
Since the single carrier modes of IEEE 802.11b and g use linear modulation formats
like BPSK or QPSK, the transmit signal power varies between symbol sampling times.
These power variations are determined by the transmit filter, which isn't defined in the
standard. The WLAN application allows fine tuning of the PVT measurements on
signals with high crest factors by an adjustable moving average filter and two different
reference power settings.
The reference power equals the 100 % setting for the rise / fall time calculation. Either
the maximum PPDU power or the mean PPDU power can be chosen as reference
power. Using the mean PPDU power, rare power spikes within the PPDU do not
influence the rise / fall time measurement.
A moving average filter with sufficient length eliminates the influence of the modulation
on the power measurement and will therefore lead to a smoother trace. While a long
average length leads to more stable measurement results, it naturally increases the
rise / fall times compared to no averaging.
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R&S FSQ-K90/K91/K91n/K91ac Measurements and Result Displays
Measurements
2.2.1.3 EVM vs Symbol
► Press the "EVM vs Symbol" softkey in the EVM measurement menu to select the
EVM vs Symbol result display.
The EVM vs Symbol result display shows the EVM measured over all demodulated
symbols in the current capture buffer. The results are displayed on a per-symbol basis,
with blue vertical lines marking the boundaries of each PPDU. Note that PPDU
boundary lines are only displayed if the number of analyzed PPDUs is less than 250.
EVM vs Symbol (example based on an IEEE 802.11n MIMO signal)
For IEEE 802.11a, j, g (OFDM), n and ac, the minimum, average and maximum traces
are displayed.
For IEEE 802.11b & g (Single Carrier), two EVM traces are displayed. The trace
labeled "VEC ERR IEEE" shows the error vector magnitude as defined in the IEEE
802.11b & g standards. For the trace labeled "EVM", a commonly used EVM definition
is applied, which is the square root of the momentary error power normalized by the
averaged reference power. For details of this measurement, refer to chapter 4.
Remote: CONFigure:BURSt:EVM:ESYMbol[:IMMediate]
EVM vs Symbol: Y-axis Scaling
Auto Scaling
Turns automatic scaling of the y-axis on and off.
When you turn this feature on, the application automatically scales the y-axis after
each sweep.
When you turn it off, use "Per Division" to determine the scale of the y-axis.
Auto scaling is always on when the unit displayed on the y-axis is dB.
Remote: DISPlay[:WINDow<1|2>]:TRACe:Y[:SCALe]:AUTO <State>
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Measurements
Per Division
Defines the scaling of the y-axis when auto scaling is inactive.
Remote: DISPlay[:WINDow<1|2>]:TRACe:Y[:SCALe]:PDIVision <Size>
Unit
Selects the unit of the y-axis.
Remote: UNIT:EVM <Unit>
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Measurements
2.2.1.4 EVM vs Carrier
Available for IEEE 802.11a, g (OFDM), j, n, ac, Turbo Mode.
► Press the "EVM vs Carrier" softkey in the EVM measurement menu to select the
EVM vs Carrier result display.
The EVM vs Carrier result display shows all EVM values recorded on a per-carrier
basis over all recorded symbols in all PPDUs.
The result display contains one trace each for the minimum, average and maximum
results.
EVM vs Carrier (example based on an IEEE802.11a signal)
The scaling of the y-axis can be modified to allow the results to be scaled to an
optimum level.
► Press the "Y Axis/Div" softkey to open a dialog box that controls the scale of the y-
axis. For more information see "EVM vs Symbol: Y-axis Scaling" on page 38.
Remote: CONFigure:BURSt:EVM:ECARrier[:IMMediate]
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Measurements
2.2.1.5 Frequency Error vs Preamble
► Press the "Error (Freq Phase)" softkey in the EVM measurement menu to select
the Frequency Error vs Preamble result display.
Note that the softkey also selects the Phase Error vs Preamble result display. The
Frequency Error vs Preamble is selected if the "FREQ" label on the softkey is
highlighted.
The Frequency Error vs Preamble result display shows the relative frequency error
values recorded over the preamble part of the PPDU.
A minimum, average and maximum trace are displayed.
Frequency Error vs Preamble Results (example based on an IEEE802.11a signal)
► Press the "Y Axis/Div" softkey to open a dialog box that controls the scale of the y-
axis. For more information see "EVM vs Symbol: Y-axis Scaling" on page 38.
Remote:
CONFigure:BURSt:PREamble[:IMMediate]
CONFigure:BURSt:PREamble:SELect <ResultType>
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R&S FSQ-K90/K91/K91n/K91ac Measurements and Result Displays
Measurements
2.2.1.6 Phase Error vs Preamble
► Press the "Error (Freq Phase)" softkey in the EVM measurement menu twice to
select the Phase Error vs Preamble result display.
Note that the softkey also selects the Frequency Error vs Preamble result display.
The Phase Error vs Preamble is selected if the "PHASE" label on the softkey is
highlighted.
The Phase Error vs Preamble result display shows the relative phase error values
recorded over the preamble part of the PPDU.
A minimum, average and maximum trace are displayed.
► Press the "Y Axis/Div" softkey to open a dialog box that controls the scale of the y-
axis. For more information see "EVM vs Symbol: Y-axis Scaling" on page 38.
Remote:
CONFigure:BURSt:PREamble[:IMMediate]
CONFigure:BURSt:PREamble:SELect <ResultType>
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R&S FSQ-K90/K91/K91n/K91ac Measurements and Result Displays
Measurements
2.2.1.7 Spectrum Flatness and Group Delay
Available for IEEE 802.11a, g (OFDM), j, n, ac and Turbo Mode.
► Press the "Spectrum Flatness" or "Spectrum (Flat Grdel)" softkey in the Spectrum
measurement menu to select the Spectrum Flatness and / or Group Delay result
display.
The information in the Spectrum Flatness and Group Delay result displays
depends on the standard.
- IEEE 802.11a, g (OFDM), j and Turbo Mode
The Spectrum Flatness and Group Delay results are displayed in the same
diagram. The Spectrum Flatness is represented by a yellow trace, the Group
Delay by a green trace.
The left diagram axis shows the scale of the Channel Flatness (in dB). The
right diagram axis shows the scale of the Group Delay (in ns).
- IEEE 802.11n, ac
The Spectrum Flatness and Group Delay results are displayed in separate
result display.
Pressing the "Spectrum (Flat Grdel)" softkey once selects the Spectrum
Flatness results, pressing it twice selects the Group Delay results.
Spectrum Flatness
The Spectrum Flatness result display shows the absolute power of a carrier. You can
use it, for example, to determine the spectral distortion caused by the DUT (for
example the transmit filter).
The results are averaged over all symbols of all recorded PPDUs.
The red lines are the limits for the Spectrum Flatness as defined by IEEE, one upper
and one lower limit line. The shape of the limit line depends on the selected standard.
The WLAN application tests the signal against these limits and shows the results in the
diagram area (pass or fail).
Spectrum Flatness (yellow trace) and Group Delay (green trace) results (example based on an
IEEE802.11a signal)
Software Manual 1157.3135.42 - 08 43
R&S FSQ-K90/K91/K91n/K91ac Measurements and Result Displays
Measurements
Spectrum Flatness (example based on an IEEE802.11n MIMO signal)
Remote:
CONFigure:BURSt:SPECtrum:FLATness[:IMMediate]
CONFigure:BURSt:SPECtrum:FLATness:SELect
Group Delay
The Group Delay result display shows the derivation of phase over frequency.
Note that the trace displayed in the Group Delay result display is mean adjusted.
Group Delay results (example based on an IEEE802.11n MIMO signal)
In case of measurements on IEEE 802.11n and ac signals, the Spectrum Flatness and
Group Delay measurements allow for the selection between the Physical and Effective
Channel model. The Effective Channel model is the composition of the physical
channel and the MIMO encoder.
The "Chan Sel (PHY EFF)" softkey is located in the side menu (→ NEXT hotkey) of the
Spectrum measurements.
Remote:
CONFigure:BURSt:SPECtrum:FLATness[:IMMediate]
CONFigure:BURSt:SPECtrum:FLATness:SELect
CONFigure:BURSt:SPECtrum:FLATness:CSELect
Software Manual 1157.3135.42 - 08 44
R&S FSQ-K90/K91/K91n/K91ac Measurements and Result Displays
Measurements
2.2.1.8 Spectrum FFT
► Press the "Spectrum FFT" softkey in the Spectrum measurement menu to select
the Spectrum FFT result display.
The Spectrum FFT result display shows the power over the selected signal bandwidth
obtained from a FFT performed over the range of data in the Capture Buffer which lies
within the gate lines. If the gate start or gate length are altered, the results can be
updated to reflect these changes by pressing the REFRESH hotkey.
Spectrum FFT results (example based on an IEEE802.11a signal)
Remote: CONFigure:BURSt:SPECtrum:FFT[:IMMediate]
Software Manual 1157.3135.42 - 08 45
R&S FSQ-K90/K91/K91n/K91ac Measurements and Result Displays
Measurements
2.2.1.9 Constellation
► Press the "Constell" softkey in the Constellation measurement menu to select the
Constellation result display.
The Constellation diagram shows the inphase and quadrature phase results over all
recorded symbols in all PPDUs. The ideal points for the selected modulation scheme
are displayed as crosses for reference purposes.
Constellation diagram (example based on an IEEE802.11a signal
Remote: CONFigure:BURSt:CONStellation:CSYMbol[:IMMediate]
Evaluation range for the constellation diagram
By default the application displays the constellation points for all carriers that have
been evaluated.
However, you can filter the results.
► Press the "Carrier Selection" softkey.
The application opens a dialog box to filter the displayed results.
You can select to display the results for:
● A particular carrier (by its number)
● All pilot carriers
● All carriers (default)
The amount of data displayed in the Constellation results display can be reduced by
selecting the carrier or carriers for which data is to be displayed.
Carrier selection is not available when the IEEE 802.11b or g (Single Carrier)
standards are selected.
Remote: CONFigure:BURSt:CONStellation:CARRier:SELect <Carrier>
Software Manual 1157.3135.42 - 08 46
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Measurements
2.2.1.10 Constellation vs Carrier
Available for IEEE 802.11a, g (OFDM), j, n, ac, Turbo Mode.
► Press the "Constell vs Carrier" softkey in the Constellation measurement menu to
select the Constellation vs Carrier result display.
The Constellation vs Carrier result display shows the inphase and quadrature phase
results over the full range of the measured input data plotted on a per-carrier basis.
The magnitude of the inphase and quadrature part is shown on the y-axis; both are
displayed as separate traces (I → yellow color, Q → green color).
Constellation vs Carrier results (example based on an IEEE802.11n MIMO signal)
Remote: CONFigure:BURSt:CONStellation:CCARrier[:IMMediate]
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Measurements
2.2.1.11 Complementary Cumulative Distribution Function (CCDF)
► Press the "CCDF" softkey in the Statistics measurement menu to select the CCDF
result display.
The CCDF result display shows the probability of an amplitude within the gating lines
exceeding the mean power measured between the gating lines.
The x-axis displays power relative to the measured mean power.
The y-axis shows the cumulative distribution of the power levels as a percentage.
If the gate start or gate length is altered, the results can be updated to reflect these
changes by pressing the REFRESH hotkey.
CCDF results (example based on an IEEE802.11a signal)
Remote: CONFigure:BURSt:STATistics:CCDF[:IMMediate]
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R&S FSQ-K90/K91/K91n/K91ac Measurements and Result Displays
Measurements
2.2.1.12 Bit Stream
► Press the "Bit Stream" softkey in the Statistics measurement menu to select the Bit
Stream result display.
This result display shows the demodulated payload data stream over all analyzed
PPDUs.
Multi-carrier measurements
In case of multicarrier measurements (IEEE 802.11a, g (OFDM), n, ac and Turbo
Mode) the results are grouped by symbol and carrier.
Bit Stream results grouped by symbol and carrier (example based on an IEEE802.11n MIMO signal)
Single-carrier measurements
For single-carrier measurements (IEEE 802.11b, g (DSSS)) the results are grouped by
PPDU.
Bit Stream results grouped by PPDU (example based on an IEEE802.11b signal)
If no other dialog box is active, you can scroll through the results with the rotary knob
or the cursor keys.
Remote: CONFigure:BURSt:STATistics:BSTReam[:IMMediate]
Software Manual 1157.3135.42 - 08 49
R&S FSQ-K90/K91/K91n/K91ac Measurements and Result Displays
Availability of the Signal Field results
No
Content" (
Measurements
2.2.1.13 Signal Field
Available for IEEE 802.11a, g, j, n, ac, Turbo Mode.
► Press the "Signal Field" softkey in the Statistics measurement menu to select the
Signal Field result display.
This result display shows the decoded data from the "Signal" field of each analyzed
PPDU. This field contains information on the modulation used for transmission.
The analyzed PPDUs depends on your selection. You can select the type of PPDUs to
be analyzed in the demodulation settings:
● Burst To Analyze Settings, (IEEE 802.11a, b, g, j, n (SISO) and Turbo Mode)
● Bursts to Analyze (Advanced) (IEEE 802.11n (MIMO)
● PPDU to Analyze (Advanced) (IEEE 802.11ac)
The signal field information is provided as a decoded bit sequence and, where
appropriate, also in human-readable form, beneath the bit sequence for each PPDU.
Signal Field results (example based on an IEEE802.11n signal)
te that the result display is available if you have turned on "Use Signal Field
→ "Burst To Analyze Settings").
The contents of the Signal Field result display depends on the IEEE standard.
IEEE 802.11a, g and j
Burst <x> Shows the number of the PPDU.
A green bar represents a PPDU that has been decoded successfully.
Rate Shows the symbol rate per second.
Reserved Shows the reserved bit.
Length Shows the length of the payload in OFDM symbols.
Parity Shows the parity bit.
Signal Tail Shows the tail of the signal. The signal tail is preset to 0.
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R&S FSQ-K90/K91/K91n/K91ac Measurements and Result Displays
Measurements
IEEE 802.11n (SISO)
Burst <x> Shows the number of the PPDU.
A green bar represents a PPDU that has been decoded successfully.
MCS Shows the Modulation and Coding Scheme (MCS) index of the PPDU.
HTLength Shows the length of the payload in OFDM symbols.
CRC Shows the cyclic redundancy code.
Short GI Shows the length of the guard interval of the PPDU.
0: short guard interval.
1: long guard interval.
20/40 BW Shows the channel bandwidth of the PPDU.
0: 20 MHz
1: 40 MHz
IEEE 802.11n, ac (MIMO)
For each analyzed PPDU in the signal, the Signal Field results contain the HT-SIG1
and HT-SIG2 as a bit sequence (in some cases also in human readable form).
The first line of the list header indicates the HT-SIG field assigned to the corresponding
bit sequence. The second line of the list header shows the demodulation settings that
select the type of PPDU considered in the measurement ("logical filter"). The value
inside the white rectangle indicates the logical filter setting that currently applies to this
property.
PPDU <x> Shows the number of the PPDU.
A green bar represents a PPDU that has been decoded successfully.
Format Shows the format of the PPDU that has been detected.
MCS Shows the Modulation and Coding Scheme (MCS) index of the PPDU.
BW Shows the channel bandwidth of the PPDU.
0: 20 MHz
1: 40 MHz
The actual bandwidth is also displayed below the code.
HTLength Shows the length of the payload in OFDM symbols.
Nstbc Shows the space-time block coding.
GI Shows the length of the guard interval of the PPDU.
0: short guard interval (S).
1: long guard interval (L).
Ness Shows the number of extension spatial streams (N
CRC Shows the cyclic redundancy code of bits 0 - 23 in HT-SIG1 and bits 0 - 9 in HT-SIG2.
Tail Shows the tail bits of the PPDU.
ESS
)
If no other dialog box is active, you can scroll through the results with the rotary knob
or the cursor keys.
Remote: CONFigure:BURSt:STATistics:SFIeld[:IMMediate]
Software Manual 1157.3135.42 - 08 51
R&S FSQ-K90/K91/K91n/K91ac Measurements and Result Displays
≥
Measurements
Error messages and warnings
When you perform MIMO measurements, the application shows a warning message if
a PPDU could not have been properly analyzed. The corresponding PPDU is
highlighted in a color other than green.
Note that PPDUs that cause one of the following error message will be included in the
calculation of overall measurement results. Thus they might distort measurement
results.
Info: Comparison between HT-SIG Payload Length and Estimated Payload Length not
performed due to insufficient SNR
The WLAN application compares the HT-SIG length against the length estimated from
the PPDU power profile. In case of a mismatch, the corresponding entry is highlighted
orange. In case of very bad signal quality, this comparison is suppressed and this
message is displayed.
Warning: HT-SIG of PPDU was not evaluated
Decoding of the HT-SIG is not possible because there is not enough data in the
capture buffer. This could result in potential PPDU truncation.
Warning: Mismatch between HT-SIG and estimated (SNR+Power) PPDU length
The HT-SIG length and the length estimated – by the WLAN application – from the
PPDU power profile are different.
Warning: Physical Channel estimation impossible / Phy Chan results not available
Possible reasons: channel matrix not square or singular to working precision
The Physical Channel results could not be calculated. The reason could be:
● The spatial mapping can not be applied due to a rectangular mapping matrix (the
number of space time streams is not equal to number of transmit antennas).
● The estimated channel matrices are singular to working precission (inverting not
possible).
Warning: Payload Channel Estimation requires Number of PPDU Payload Symbols >=
Number of Space Time Streams Used Preamble Channel Estimation instead!
In case Channel Estimation = Payload is selected but the number of payload symbols
< number of space time streams, this warning is risen. To fix it
● select to Channel Estimation = Preamble or
● increase the number of PPDU payload symbols
number of space time streams.
Software Manual 1157.3135.42 - 08 52
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≥
≥
Measurements
Warning: IQ Offset matrix singular to working precission
Possible reasons:
1. Number of Space Time Streams < Number of Rx Antennas
2. Number of PPDU Payload Symbols < Number of Space Time Streams
IQ Offset results not available
The reason for this could be:
● make the number of Space Time Streams identical to the Number of Rx Antennas
● increase the number of PPDU payload symbols
number of space time streams.
Warning: IQ Imbalance matrix singular to working precission
Possible reasons:
1. Number of Space Time Streams < Number of Rx Antennas
2. Number of PPDU Payload Symbols < Number of Space Time Streams
IQ Imbalance results not available
The reason for this could be:
● make the number of Space Time Streams identical to the Number of Rx Antennas
● increase the number of PPDU payload symbols
number of space time streams.
Dismissed PPDUs
In case a required PPDU property does not match the corresponding property from the
list, the PPDU is dismissed. An appropriate message is provided. In addition, the
corresponding PPDU in the Capture Buffer is not highlighted by a bar.
Note that PPDUs that cause one of the following error messages are not considered in
the calculation of measurement results.
Hint: PPDU requires at least one payload symbol
Currently at least one payload symbol is required in order to successfully analyze the
PPDU. I.e. null data packet (NDP) sounding PPDUs will generate this message.
Hint: PPDU dismissed due to a mismatch with the PPDU format to be analyzed
The properties causing the mismatches for this PPDU are highlighted.
Hint: PPDU dismissed due to mismatching Nof space time streams to be analyzed
The "Number of Space Time Streams" property causes a mismatch for this PPDU.
Hint: PPDU dismissed due to truncation
For example during the signal capture process the first or the last PPDU was
truncated.
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R&S FSQ-K90/K91/K91n/K91ac Measurements and Result Displays
Measurements
Hint: PPDU dismissed due to HT-SIG inconsistencies
One or more of the following HT-SIG decoding results are outside of specified range:
MCS index, Number of additional STBC streams, Number of space time streams, CRC
Check failed, non zero tail bits.
Hint: Channel matrix singular to working precision
Channel equalizing (for Burst Length Detection, fully and user compensated
measurement signal) is not possible because the estimated channel matrix is singular
to working precision.
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Measurements
2.2.1.14 PLCP Header
Available for IEEE 802.11b and g (single carrier).
► Press the "PLCP Header" softkey in the Statistics measurement menu to select the
PLCP Header result display.
The PLCP Header results display shows the decoded data from the PLCP header of
the PPDU.
Burst Shows the number of the decoded PPDU.
A green bar represents a PPDU that has been decoded successfully.
Signal Shows the signal field.
The number below the bit sequence represents the decoded data rate.
Service Shows the service field.
Bits that currently used are displayed in a blue font. The meaning of the highlighted bits is
shown below:
Bit 0 to 1
Bit 2:
Shows "---" if the symbol clock is not locked.
Shows "Locked" if the symbol clock is locked.
Bit 3
Shows "---" if the data rate is below 5.5 Mbit/s.
Shows "CCK" if CCK modulation has been selected.
Shows "PPBC" if PPBC modulation has been selected.
Bit 7
Shows "---" if the length extension bit is not set.
Shows ">8/11" if the length extension bit is set.
PSDU Length Shows the length field.
The number below the bit sequence represents the decoded time to transmit the PSDU.
CRC Shows the CRC field.
"OK" is displayed if the CRC passes. If it fails, "FAILED" is displayed.
PLCP Header Results (example based on an IEEE802.11b signal)
If necessary, you can scroll through the results with the cursor keys or the rotary knob.
Remote: CONFigure:BURSt:STATistics:SFIeld[:IMMediate]
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Measurements
2.2.2 Frequency Sweep Measurements
The following measurement results are obtained in frequency sweep mode:
● Spectrum Emission Mask
● Spectrum ACPR (IEEE 802.11a, b, g, n, ac & Turbo Mode)
● Spectrum ACP (IEEE 802.11j)
Frequency sweep measurements use different signal data than I/Q measurements.
Thus, it is not possible to run an I/Q measurement and then view the results in the
frequency sweep measurement and vice versa. Also, because each of the frequency
sweep measurements use different settings to obtain signal data, it is not possible to
run a frequency sweep measurement and view the results in another frequency sweep
measurement.
All frequency sweep measurements run in full screen mode. Frequency sweep
measurements are only available when RF input is selected.
2.2.2.1 Spectrum Emission Mask
► Press the "Spectrum Mask" softkey in the Spectrum measurement menu to select
the Spectrum Emission Mask (SEM) measurement.
The Spectrum Mask results display shows power against frequency. The span of the
results corresponds to the signal bandwidth. Thus, it depends on the selected
standard.
A limit line representing the spectrum mask specified for the selected standard is
displayed and an overall pass/fail status is displayed for the obtained results against
this limit line.
The application automatically sets some markers to indicate the peak levels in the
corresponding SEM range.
Fig. 7 Spectrum Emission Mask measurement (example based on an IEEE802.11a signal)
Software Manual 1157.3135.42 - 08 56
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Measurements
If the "Sweep Count (Mask/ACP)" parameter in the "General Settings" dialog box is set
to any value other than 1, the measurement is performed over the specified number of
sweeps.
When the measurement is performed over multiple sweeps a max hold trace is
displayed as well as an average trace.
Remote: CONFigure:BURSt:SPECtrum:MASK[:IMMediate]
SEM Settings
The Spectrum Emission Mask measurement can be configured in the "SEM Settings"
dialog box. The corresponding softkey is located in the side menu. You can acces the
side menu with the NEXT hotkey.
Fig. 8 ACP Settings view
Remote:
CONFigure:BURSt:SPECtrum:MASK:SELect <Standard>
[SENSe:]POWer:SEM <SEMType>
[SENSe:]POWer:SEM:TRACe:REDuction <Method>
SEM according to
Selects the Spectrum Emission Mask definition for the measurement. The contents of
the dropdown menu depend on the selected standard.
If you select the "User" entry, you can select a custom SEM in the "File Name" field.
You can create a custom SEM in an xml file and copy it to the R&S FSQ. For more
information on the contents and structure of SEM files refer to the documentation of the
R&S FSQ.
IEEE 802.11a, b, g, j an Turbo Mode support the following SEM definitions.
● ETSI – Settings and limits are as specified in the standard
● IEEE – Settings and limits are as specified in the standard
● User – Settings and limits are configured via an XML file
Remote: [SENSe:]POWer:SEM <SEMType>
Software Manual 1157.3135.42 - 08 57
R&S FSQ-K90/K91/K91n/K91ac Measurements and Result Displays
Transmit spectral mask for 20 MHz
SENS:POW:SEM IEEE
Transmit spectral mask for 20 MHz
Transmit spectral mask for 20 MHz
REVmb™/D8.0, March 2011
Transmit spectral mask for 20 MHz
REVmb™/D8.0, March 2011
REVmb™/D8.0, March 2011
it spectral mask for 20 MHz
REVmb™/D8.0, March 2011
Measurements
For a list of supported SEM configurations for IEEE 802.11n and 802.11ac, see the
table below.
SEM Settings The spectrum emission mask measurement
is performed according to the standard
IEEE 802.11n-2009 20M@2.4G IEEE Std 802.11n™-2009
Figure 20-17:
channel
IEEE 802.11n-2009 40M@2.4G IEEE Std 802.11n™-2009
Figure 20-18: Transmit spectral mask for a
40 MHz channel
IEEE 802.11n-2009 20M@5G IEEE Std 802.11n™-2009
Figure 20-17:
channel
IEEE 802.11n-2009 40M@5G IEEE Std 802.11n™-2009
Figure 20-18: Transmit spectral mask for a
40 MHz channel
IEEE 802.11mb/D08 20M@2.4G IEEE Std 802.11n™-2009
Figure 20-17:
transmission
IEEE Draft P802.11-
Figure 19-17:
transmission in the 2.4 GHz band
IEEE 802.11mb/D08 40M@2.4G IEEE Std 802.11n™-200
Figure 20-18: Transmit spectral mask for a
40 MHz channel
IEEE Draft P802.11-
Figure 19-18: Transmit spectral mask for a 40
MHz channel in the 2.4 GHz band
Remote Control Command
SENS:POW:SEM 'IEEE_2009_20_2_4'
Supported for backwards compatibility:
SENSe:POWer:SEM 'IEEE_2009_40_2_4'
SENSe:POWer:SEM 'IEEE_2009_20_5'
SENSe:POWer:SEM 'IEEE_2009_40_5'
SENSe:POWer:SEM 'IEEE_D08_20_2_4'
SENSe:POWer:SEM 'IEEE_D08_40_2_4'
IEEE 802.11mb/D08 20M@5G IEEE Draft P802.11-
Figure 19-19: Transm
transmission in the 5 GHz band
IEEE 802.11mb/D08 40M@5G IEEE Draft P802.11-
Figure 19-20: Transmit spectral mask for a
40 MHz channel in the 5 GHz band
IEEE 802.11ac/D1.1 20M@5G IEEE P802.11ac™/D1.1, August 2011
Figure 22-17: Transmit spectral mask for a
20 MHz channel
IEEE 802.11ac/D1.1 40M@5G IEEE P802.11ac™/D1.1, August 2011
Figure 22-18: Transmit spectral mask for a
40 MHz channel
IEEE 802.11ac/D1.1 80M@5G IEEE P802.11ac™/D1.1, August 2011
Figure 22-19: Transmit spectral mask for a
80 MHz channel
Software Manual 1157.3135.42 - 08 58
SENSe:POWer:SEM 'IEEE_D08_20_5'
SENSe:POWer:SEM 'IEEE_D08_40_5'
SENSe:POWer:SEM 'IEEE_AC_D1_1_20_5'
SENSe:POWer:SEM 'IEEE_AC_D1_1_40_5'
SENSe:POWer:SEM 'IEEE_AC_D1_1_80_5'
R&S FSQ-K90/K91/K91n/K91ac Measurements and Result Displays
TX Channel Power Peak
The Tx Channel peak power is used as reference power.
TX Channel Power
The TX Channel power is used as reference power.
Peak
Uses the peak value of the captured data to draw the complete
Trace detector
Uses the value according to the detector setting as defined in the
Measurements
File Name
Shows the name of the file that contains the data of the current spectrum emission
mask.
The file type is .xml. If you press the arrow button (
the file manager to locate and select a SEM file. If you select a SEM not included in the
"SEM According To" dropdown menu, the application automatically selects "User" in
that field.
Remote: MMEMory:LOAD:IQ:STATe 1,<FileName>
the "Reference Power" settin
Reference Power
Selects the calculation method of the reference power.
Remote: CONFigure:BURSt:PVT:RPOWer <ReferencePower>
Trace Reduction
Selects the method of data reduction used to draw the trace for each frequency
segment of the Spectrum Emission Mask.
The SEM measurement captures the data according to the detector setting defined for
each frequency segment. The detector for each frequency segment is defined in the
SEM definition (xml file).
), the WLAN application opens
trace.
SEM definition file to draw the trace.
If the Peak detector has been defined for a frequency segment, the
trace reduction does not have an effect on the trace for that
frequency segment.
If the RMS detector has been defined for a frequency segment, the
trace will be smoother compared to the Peak detector.
Remote: [SENSe:]POWer:SEM:TRACe:REDuction <Method>
Bandwidth
Shows the bandwidth of the Tx channel.
Remote: ---
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Measurements
RBW
Shows the resolution bandwidth used to determine the reference power in the
frequency segment of the Tx channel.
Remote: ---
SEM Configuration
The SEM configuration shows the settings and limits applied over specified frequency
ranges around the TX channel. The settings displayed depend on the selected "Link
Direction" and "Power Class".
For more information about the parameters refer to the documentation of the
R&S FSQ.
Fig. 9 SEM Configuration
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Measurements
2.2.2.2 Spectrum ACPR
Available for IEEE 802.11a, b, g, n, ac & Turbo Mode.
► Press the "Spectrum ACPR" softkey in the Spectrum measurement menu to select
the Adjacent Channel Power Relative (ACPR) measurement.
The Spectrum ACPR (Adjacent Channel Power (Relative)) measurement provides
information about leakage into adjacent channels. The results show the relative power
measured in the three nearest channels on either side of the measured channel.
This measurement is similar to the Adjacent Channel Power measurement provided by
the Spectrum Analyzer.
Fig. 10 Spectrum ACPR Results
If the "Sweep Count (Mask/ACPR)" parameter in the "General Settings" dialog box is
set to any value other than 1, the measurement is performed over the specified
number of sweeps. When the measurement is performed over multiple sweeps, a max
hold trace is displayed as well as an average trace.
Remote: CONFigure:BURSt:SPECtrum:ACPR[:IMMediate]
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Measurements
2.2.2.3 Spectrum ACP
Available for IEEE 802.11j.
► Press the "ACP (Rel Abs)" softkey in the Spectrum measurement menu to select
the Adjacent Channel Power (ACP) measurement.
Pressing the softkey repeatedly switches between relative and absolute display of
the results.
The ACP (absolute and relative) measurement provides information about leakage into
adjacent channels. The results show the absolute and relative power measured in the
three nearest channels on either side of the Tx channel.
If the "Sweep Count (Mask/ACP)" parameter in the "General Settings" dialog box is set
to any value other than 1, the measurement is performed over the specified number of
sweeps. When the measurement is performed over multiple sweeps, a max hold trace
is displayed as well as an average trace.
If the current measurement frequency and measurement type (relative or absolute)
have a limit specified by the standard, the limit is displayed and the result is displayed
in either green or red depending on whether the result passes or fails the
corresponding limit.
Remote:
CONFigure:BURSt:SPECtrum:ACPR[:IMMediate]
[SENSe:]POWer:ACHannel:MODE <Mode>
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Measurement Results
2.3 Measurement Results
The header table below the title bar shows the overall measurement settings used to
obtain the current measurement results.
Fig. 37 Overall measurement settings summary for IEEE 802.11a , g (OFDM), j and Turbo Mode
Fig. 38 Measurement settings summary for IEEE 802.11b & g (Single Carrier)
Fig. 11 Measurement settings summary for IEEE 802.11n SISO
Fig. 12 Measurement settings summary for IEEE 802.11ac
The header table includes the following information.
Frequency Current center frequency of the signal analyzer. The frequency should match the frequency of
the signal to get valid data.
Fs Current sample rate used to sample the signal.
Available for IEEE 802.11n.
Signal Level Setting Expected mean signal level of the input signal.
Available for IEEE 802.11a, g (OFDM), j, n, ac and Turbo Mode.
Ref Level Current reference level of the analyzer. The reference level usually corresponds to the peak level
of the signal.
Available for IEEE 802.11b & g (Single Carrier).
External Att Current external attenuation of the analyzer. External attenuation is attenuation applied before
the signal enters the RF input or one of the baseband inputs.
Note that the external attenuation is an offset added or substrated by the software. It does not
have an effect on the hardware settings of the signal analyzer (reference level and internal
attenuation).
Positive values correspond to attenuation, negative values correspond to gain.
Example:
External Att = 10 dB means that the signal is attenuated by 10 dB before it enters the RF input.
External Att = -20 dB means that the signal is amplified by 20 dB before it enters the RF input.
Capture Time Current signal capture time.
The capture time defines the amount of data the application captures during one sweep.
No Samples Number of samples captured during the capture time with the selected sample rate.
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Measurement Results
Burst Type Type of PPDU currently being analyzed.
For more information on PPDU types see "Burst Type" (→ Demod Settings).
Available for IEEE 802.11a, g (OFDM), j and Turbo Mode.
Preamble Type Type of preamble of currently analyzed PPDUs.
For more information on preamble types see "Preamble Type" (→ Demod Settings).
Available for IEEE 802.11b & g (Single Carrier).
PPDU/MCS Index/GI Type of PPDU, MCS Index and Guard Interval of currently analyzed PPDUs.
For more information on PPDU frame formats, guard intervals and MCS index see
− "Burst Type to Measure" (802.11n)
− "MCS Index to Use" (802.11n)
− "Guard Interval Length" (802.11n)
− "PPDU Format to Measure" (802.11ac)
− "MCS Index to Use" (802.11ac)
− "Guard Interval Length" (802.11ac)
Available for IEEE 802.11n and ac.
Modulation Current modulation of the analyzed PPDU.
The modulation is either determined by the "Auto Demodulation" or the "PSDU Mod to Analyze"
(→ Demod Settings).
Available for IEEE 802.11a, b, g, j, n (SISO) & Turbo Mode.
Meas Setup Current MIMO setup (number of Tx and Rx antennas.
Available for 802.11n (MIMO) and ac.
No Of Data Symbols Current minimum and maximum number of data symbols that a PPDU may have if it is to be
considered in results analysis.
Available for IEEE 802.11a, g (OFDM), j, n, ac and Turbo Mode.
PSDU Data Length Current minimum and maximum number of data bytes that a PPDU may have if it is to be
considered in results analysis.
Available for IEEE 802.11b & g (Single Carrier) only.
Sweep Mode Current sweep mode.
− CONT for continuous measurements
− SGL for single measurements.
For more information see "Performing Measurements".
Trigger Mode (TRG) Current trigger source.
− FREE RUN for free run measurements
− EXT for external trigger
For more information see "Trigger Settings" (→ General Settings).
If you perform gated measurements, acorresponding label is displayed here.
Input Path Current input source.
For more information see "Input" (→ General Settings).
Burst x of y (z) Currently analyzed PPDU (x) out of the total number of PPDUs to analyze (y). Shown
The number in brackets (z) is the number of analyzed PPDUs in the current capture buffer.
This PPDU information is displayed when the "Overall Burst Count" (→ General Settings) is
turned on.
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R&S FSQ-K90/K91/K91n/K91ac Measurements and Result Displays
Measurement Results
2.3.1 Result Summary
The Result Summary is displayed in the "List" display mode. It contains the
measurement results in numerical form and provides a limit check to confirm if results
comply with the selected IEEE standard.
The table layout depends on the selected IEEE standard.
2.3.1.1 IEEE 802.11a, b, g and j
► Press the "Display List" softkey to access the Result Summary.
For each result, the minimum, mean and maximum values are displayed.
The application also checks the results against the defined limits.
If the result passes the limit check, the value of the result is displayed in a green font. If
it fails the limit check, the font turns red and the result is labeled with a '*' sign. If no
limits are defined for a result type, it is displayed in white color.
The limit values, if defined, are displayed in the column next to the results.
For more information on limits see "Limit Values in the Result Summary".
For some results, the table contains the values in more than one unit.
Fig. 13 Result Summary Table
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R&S FSQ-K90/K91/K91n/K91ac Measurements and Result Displays
Measurement Results
No. of Bursts Shows the number of PPDUs that have been analyzed
EVM All Carriers Shows the EVM of the payload symbols over all carriers
EVM Data Carriers Shows the EVM of the payload symbols over all data carriers
EVM Pilot Carriers Shows the EVM of the payload symbols over all pilot carriers
I/Q Offset Shows the transmitter center frequency leakage relative to the total Tx channel
power
Gain Imbalance Shows the amplification of the quadrature phase component of the signal relative
to the amplification of the in-phase component
Quadrature Error Shows the deviation of the quadrature phase angle from the ideal 90°
Center Frequency Error Shows the frequency error between the signal and the current center frequency
Symbol Clock Error Shows the clock error between the signal and the sample clock of the R&S FSQ
in parts per million (ppm)
Burst Power Shows the power of the PPDU
Crest Factor Shows the ratio of the peak power to the mean power of the signal
2.3.1.2 IEEE 802.11n and ac
In case of measurements on MIMO systems, the result summary is split into several
tables.
► Press the "Display Global" softkey to access the Global Result Summary that
contains results of the overall measurement.
► Press the "Display List STC" softkey to access a result summary that contains
results specific to each transmission channel in the measurement.
Note that if the "Display Global" softkey is visible, you have to press the softkey
once to get access to the "Display List STC" softkey and vice versa.
Global Result Summary
For each result, the minimum, mean and maximum values are displayed.
The application also checks the results against the defined limits.
If the result passes the limit check, the value of the result is displayed in a green font. If
it fails the limit check, the font turns red and the result is labeled with a '*' sign. If no
limits are defined for a result type, it is displayed in white color.
The limit values, if defined, are displayed in the column next to the results.
For more information on limits see "Limit Values in the Result Summary".
For some results, the table contains the results in more than one unit.
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Measurement Results
Fig. 14 Global Result Summary, IEEE 802.11 n (MIMO)
Recognized Bursts Shows the number of PPDUs that have been recognized in the current
capture buffer.
Analyzed Bursts Shows the total number of PPDUs that have been analyzed and are taken
into account for the result statistics.
Analyzed Bursts Phy. Chan Shows the number of PPDUs in the physical channel that have been
analyzed
EVM All Carriers Shows the EVM of the payload symbols over all carriers
EVM Data Carriers Shows the EVM of the payload symbols over all data carriers
EVM Pilot Carriers Shows the EVM of the payload symbols over all pilot carriers
Center Frequency Error Shows the frequency offset between the signal and the current center
frequency
Symbol Clock Error Shows the clock error between the signal and the sample clock of the
R&S FSQ in parts per million (ppm)
STC Result Summary
The STC Result Summary shows results for any particular transmission channel in the
measurement. It is available with different content.
The application also checks the results against the defined limits.
If the result passes the limit check, the value of the result is displayed in a green font. If
it fails the limit check, the font turns red and the result is labeled with a '*' sign. If no
limits are defined for a result type, it is displayed in white color.
The limit values, if defined, are displayed in the column next to the results.
For more information on limits see "Limit Values in the Result Summary".
For some results, the table contains the results in more than one unit.
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Measurement Results
STC Overview (Split Screen Mode of the MIMO Result Summary)
The STC Overview result summary contains a combined summary for all results
specific for each antenna. For a more detailed result summary for each antenna see
"STC Detail" below.
Fig. 15 Overview STC Result Summary, IEEE 802.11 n (MIMO)
For each transmission channel (receiving antenna Rx<n>, transmitting antenna Tx<n>
and stream<n>), the result summary shows the following results.
I/Q Offset Shows the transmitter center frequency leakage relative to the total Tx channel
power
Gain Imbalance Shows the amplification of the quadrature phase component of the signal relative
to the amplification of the in-phase component
Burst Power Shows the power of the PPDU.
Crest Factor Shows the ratio of the peak power to the mean power of the signal
BER Pilot Shows the bit error rate of the pilot carriers
EVM All Carriers Shows the EVM of the payload symbols over all carriers
EVM Data Carriers Shows the EVM of the payload symbols over all data carriers
EVM Pilot Carriers Shows the EVM of the payload symbols over all pilot carriers
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Measurement Results
STC Detail
For each transmission channel there is a detailed STC Result Summary.
The results are the same as in the STC Overview, but with more details. The result
summary shows the minimum, mean and maximum values for each result. It also
contains the limit check results for several values.
If the result passes the limit check, the value of the result is displayed in a green font. If
it fails the limit check, the font turns red and the result is labeled with a '*' sign. If no
limits are defined for a result type, it is displayed in white color.
For more information on limits see "Limit Values in the Result Summary".
► In the STC Overview, select the screen of the antenna in question.
► Press the DISP key.
► Press the "Full Screen" softkey.
The application displays the STC results in full screen mode.
Fig. 16 STC Overview Result Summary, IEEE 802.11 n (MIMO)
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R&S FSQ-K90/K91/K91n/K91ac Measurements and Result Displays
Measurement Results
2.3.2 Limit Values in the Result Summary
The application allows you to change and customize the limit values for results that are
tested against a limit.
► Press LINES key.
► Select a limit value with the rotary knob or the cursor keys.
The selected limit is highlighted in blue.
► Press the ENTER key.
► Enter a new limit value.
Customizing limits is possible in all WLAN standards. However, it is not possible in the
STC Result Summary (MIMO results).
Fig. 17 Editing Limit Values
Remote: CALCulate:LIMit:BURSt:… commands in the CALCulate:LIMit Subsystem.
Limits are modified for the currently selected modulation scheme. Each modulation
scheme may have its own set of user-defined limits.
Pressing the "Default Current" softkey resets all limits for the current modulation
scheme to the values specified in the selected standard.
Remote: ---
► Pressing the "Default All" softkey resets all limits for all modulation schemes to the
values specified in the selected standard.
Remote: CALCulate<1|2>:LIMit<1>:BURSt:ALL DEFault | <Limit>,<Limit>,…
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R&S FSQ-K90/K91/K91n/K91ac Measurements and Result Displays
Measurement Results
The results displayed in this table are for the entire measurement. If a specific number
of PPDUs has been requested that requires more than one sweep, the result summary
is updated at the end of each sweep. The number of PPDUs measured and the
number of PPDUs requested are displayed to show the progress through the
measurement.
If more than one PPDU is evaluated (several analyzed PPDUs in the capture buffer or
with the help of Overall Burst Count), the Min/Mean/Max columns show the minimum,
mean or maximum values of the PPDU results.
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R&S FSQ-K90/K91/K91n/K91ac Configuration
General Settings
3 Configuration
3.1 General Settings
The "General Settings" tab of the "General Settings" dialog box contains settings to
define the basic measurement configuration.
► Press the "General Settings" softkey to open the "General Settings" dialog box.
Fig. 18 General Settings view
The "General Settings" tab contains the following sets of parameters.
● Signal Characteristics on page 73
● Level Settings on page 75
● Data Capture Settings on page 78
● Trigger Settings on page 80
● I/Q Settings on page 83
● Input Settings on page 83
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R&S FSQ-K90/K91/K91n/K91ac Configuration
General Settings
3.1.1 Signal Characteristics
The "Signal Characteristics" contain settings to configure the expected input signal.
3.1.1.1 Standard
Selects the WLAN standard you want to measure against.
The availability of many settings as well as the applied limits and limit lines depend the
selected standard.
The WLAN application supports the following IEEE standards.
● IEEE 802.11a
● IEEE 802.11b
● IEEE 802.11g
● IEEE 802.11j
● IEEE 802.11n
● IEEE 802.11ac
● IEEE 802.11 OFDM Turbo Mode
The available standards depend on the options that have been installed.
Remote: CONFigure:STANdard <Standard>
3.1.1.2 Frequency
Defines the center frequency of the signal you want to measure.
When you change the frequency, the application automatically updates the Channel
No.
In case you are using the baseband input, you can also change the frequency.
However, the frequency range is limited depending on the I/Q Path you have selected:
● IQ Path = I or Q: Range = 0 to 35 MHz
● IQ Path = I + j*Q: Range = -35 to 35 MHz
Remote: [SENSe:]FREQuency:CENTer <Frequency>
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R&S FSQ-K90/K91/K91n/K91ac Configuration
General Settings
3.1.1.3 Channel No
Defines the channel you want to measure.
When you change the channel number, the application automatically updates the
Frequency.
Available for measurements on the RF input.
Remote: CONFigure:CHANnel <Channel>
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R&S FSQ-K90/K91/K91n/K91ac Configuration
General Settings
3.1.2 Level Settings
The "Level Settings" contain settings to configure the level of the expected signal.
3.1.2.1 Automatic Level Detection (Auto Level)
Turns automatic detection of the ideal reference level on and off.
When you turn on automatic level detection, the application measures the signal and
determines the ideal reference level before each sweep. Because of this additional
measurement, this process slightly increases the measurement time. You can define
the measurement time of that measurement with the Auto Level Time.
Automatic level detection also optimizes RF attenuation and the internal preamplifier.
Alternatively, you can perform an automatic level detection whenever necessary with
the AUTO LVL hotkey.
Remote: CONFigure:POWer:AUTO <State> | ONCE
Automatic vs manual selection of the reference level
Automatic level detection is an easy and fast method to determine the ideal level
settings. However, there might be situations when it is better to select the level settings
manually.
● If measurement speed is an issue.
For measurement speed issues also see "Trigger Settings".
● If you want to prevent damage to the mechanical attenuator.
During the auto level measurement, the application tries different attenuation
levels. This process requires multiple switching operations.
● If you want to measure signals near 0 Hz.
In that case, the level detection algorithm does not work reliably.
● If the idle periods between PPDUs are longer than the auto level time.
In this case, the application might not be able to capture a (complete) PPDU during
the auto level measurement.
Adjust the auto level time accordingly in such cases. Note however, that
measurement times increase accordingly, especially if more than one sweep is
necessary to determine the ideal reference level.
Note:
If you are using auto leveling and your signal contains PPDUs with different power
levels, make sure that the auto level time is sufficient to capture the PPDU with the
highest power level.
For more information on defining level settings manually, see "Advanced Settings".
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R&S FSQ-K90/K91/K91n/K91ac Configuration
General Settings
3.1.2.2 Ref Level / Signal Level (RF Input)
Defines the expected mean level (signal level) or peak level (reference level) of the RF
input signal.
The signal level is updated after an automatic level detection measurement has been
executed when RF input is selected.
Note that the signal level corresponds to the reference level in case of IEEE 802.11b
and 802.11g (Single Carrier) measurements.
For all other standards, the application automatically sets the reference level to a value
10 dB higher than the expected signal level. This is due to the high Crest Factor of
those signals.
Available for measurements on the RF input.
Remote: CONFigure:POWer:EXPected:RF <Level>
3.1.2.3 Signal Level (Baseband Input)
"Reference Level" or "Signal Level" define the expected level of the analog baseband
input signal.
The Ref Level (Baseband) is updated after an automatic level detection measurement
has been executed when baseband input is selected.
Note that the signal level corresponds to the reference level in case of IEEE 802.11b
and 802.11g (Single Carrier) measurements.
For all other standards, the application automatically sets the reference level to a value
10 dB higher than the expected signal level. This is due to the high Crest Factor of
those signals.
Available for measurements on the analog baseband input (R&S FSQ-B71).
Remote: CONFigure:POWer:EXPected:IQ <Level>
3.1.2.4 Ext Att
Defines the external attenuation applied to the RF signal.
External attenuation is attenuation applied before the signal enters the RF input or one
of the baseband inputs.
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R&S FSQ-K90/K91/K91n/K91ac Configuration
General Settings
Note that the external attenuation is an offset added or substrated by the software. It
does not have an effect on the hardware settings of the signal analyzer (reference level
and internal attenuation).
All displayed power level values will be shifted by this value.
Positive values correspond to attenuation, negative values correspond to gain.
Remote: DISPlay[:WINDow]:TRACe:Y[:SCALe]:RLEVel:OFFSet <Attenuation>
3.1.2.5 Full Scale Level
Defines the expected level of the digital baseband input signal.
Available for measurements on the digital baseband input (R&S FSQ-B17).
Remote: DISPlay[:WINDow]:TRACe:Y[:SCALe]:RLEVel:IQ <Level>
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R&S FSQ-K90/K91/K91n/K91ac Configuration
General Settings
3.1.3 Data Capture Settings
The "Data Capture Settings" contain settings that configure the amount of data that is
captured.
3.1.3.1 Capture Time
Defines the time (and therefore the amount of I/Q data) to be captured in a single
measurement sweep.
Remote: [SENSe:]SWEep:TIME <SweepTime>
3.1.3.2 Overall Burst Count
Turns the analysis of a particular number of PPDUs on and off.
When you turn the overall PPDU count on, you can define a particular number of
PPDUs that should be captured and analyzed. In that case, the application captures
data , until the required number of PPDUs has been captured (even if it has to perform
several consecutive sweeps).
If the overall PPDU count is off, the application analyzes all PPDUs that have been
found in the capture buffer.
Remote: [SENSe:]BURSt:COUNt:STATe <State>
3.1.3.3 No of Bursts to Analyze
Defines the number of PPDUs to be analyzed.
If a single sweep is not sufficient to capture the defined number of PPDUs, the
application continues to capture data until the required number of PPDUs of the
selected type has been captured.
Available if Overall Burst Count is on.
Remote: [SENSe:]BURSt:COUNt <PPDUs>
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R&S FSQ-K90/K91/K91n/K91ac Configuration
General Settings
3.1.3.4 Sweep Count (Mask/ACPR)
Defines the number of sweeps that the application performs in case of frequency
sweep measurements (ACPR and Spectrum Mask).
Remote: [SENSe:]SWEep:COUNt <Sweeps>
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R&S FSQ-K90/K91/K91n/K91ac Configuration
The IF Power trigger mode is not available for ETSI Spectrum Mask measurements. If
an
active, the
t
General Settings
3.1.4 Trigger Settings
The "Trigger Settings" contains settings to configure triggered measurements.
3.1.4.1 Trigger Mode
Selects the source of the trigger for the measurement sweep.
The application supports the following trigger sources:
● Free Run
The measurement sweep starts immediately after you start the measurement.
● External
Triggers the measurement via a TTL signal applied to the EXT TRIGGER/GATE
interface on the rear panel of the R&S FSQ. You can define the level of this trigger
signal with Trigger Level.
● IF Power
The measurement sweep starts when the signal power meets or exceeds the
specified power trigger level.
ETSI Spectrum Mask measurement is selected while the power trigger is
rigger mode automatically changes to Free Run.
If you are using the digital baseband input (R&S FSQ-B17), the only possible trigger
setting is Free Run.
Remote: TRIGger[:SEQuence]:MODE <TriggerSource>
3.1.4.2 Trigger Offset
Defines the time offset between the trigger event and the start of the sweep. A
negative value starts the measurement prior to the trigger event (pre-trigger).
Unavailable for Free Run measurements.
Remote: TRIGger[:SEQuence]:HOLDoff <Delay>
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General Settings
3.1.4.3 Trigger Holdoff
Defines the minimum time (in seconds) that must pass between two trigger events.
Trigger events that occur during the holdoff time are ignored.
Remote: TRIGger[:SEQuence]:IFPower:HOLDoff <Holdoff>
3.1.4.4 Trigger Hysteresis
Defines the distance in dB to the trigger level that the trigger source must exceed
before a trigger event occurs. Settting a hysteresis avoids unwanted trigger events
caused by noise oscillation around the trigger level.
This setting is only available for "IF Power" trigger sources. The range of the value is
between 3 dB and 50 dB with a step width of 1 dB.
Remote: TRIGger[:SEQuence]:IFPower:HYSTeresis <Hysteresis>
3.1.4.5 Trigger Level
Defines the trigger level for the external and IF power trigger.
In case of an External trigger, the trigger level is a value in Volt. In case of an IF Power
trigger, the trigger level is a value in dBm.
The label of the field changes, depending on the type of input source (Trigger Level
(RF) or Trigger Level (Baseband))
Remote:
TRIGger[:SEQuence]:LEVel[:EXTernal] <Level>
TRIGger[:SEQuence]:LEVel:POWer <Level>
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R&S FSQ-K90/K91/K91n/K91ac Configuration
General Settings
3.1.4.6 Auto Trigger Level
Turns automatic detection of the ideal IF power trigger level on and off.
When you turn automatic trigger level detection on, the application measures and
determines the power trigger level automatically at the start of each measurement
sweep. This ensures that the power trigger level is always set to the best level for
obtaining accurate results but will result in slightly increased measurement times.
Available for IF Power trigger.
Remote: TRIGger[:SEQuence]:LEVel:POWer:AUTO <State>
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R&S FSQ-K90/K91/K91n/K91ac Configuration
General Settings
3.1.5 I/Q Settings
The "I/Q Settings" contain settings to configure the inphase and quadrature phase of
the input signal.
3.1.5.1 Swap I/Q
Selects normal or inverted I/Q modulation.
● Off
Normal I/Q modulation.
● On
I and Q signals are interchanged.
Available if the I/Q Path is "I + j * Q".
Remote: [SENSe:]SWAPiq <State>
3.1.6 Input Settings
The "Input Settings" contain settings to configure the input source.
The "Input Settings" require options R&S FSQ-B17 (digital baseband) or R&S FSQB71 (analog baseband).
3.1.6.1 Input
Selects the input source.
The RF input is always available.
The analog baseband is available with option R&S FSQ-B71.
The digital baseband input is available with option R&S FSQ-B17.
Remote: INPut:SELect <Source>
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R&S FSQ-K90/K91/K91n/K91ac Configuration
STC / MIMO Settings
3.2 STC / MIMO Settings
The "STC / MIMO" tab of the "General Settings" dialog box contains settings to control
MIMO measurements (IEEE 802.11n and ac only).
► To select the "STC / MIMO" tab, set the focus on the tab (becomes blue) and move
the cursor to the left or right.
Fig. 19 STC/MIMO Settings
The "STC / MIMO" tab contains the following sets of parameters.
● DUT MIMO Configuration on page 84
● MIMO Antenna Signal Capture on page 85
3.2.1 DUT MIMO Configuration
Selects the number of Tx antennas of the device under test (DUT).
Currently, up to 4 Tx Antennas are supported.
Remote: CONFigure:WLAN:DUTConfig <Antennas>
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R&S FSQ-K90/K91/K91n/K91ac Configuration
STC / MIMO Settings
3.2.2 MIMO Antenna Signal Capture
Selects the MIMO measurement method and thus the way multiple signals are
captured.
● Simultaneous signal capture
● Sequential signal capture using an R&S®OSP switch box
● Sequential manual signal capture
The layout and contents of the dialog box depend on the method you have chosen.
The configuration options for each method are described below.
Note that each mode supports RF and Analog Baseband signal input.
Remote: CONFigure:WLAN:MIMO:CAPTure:TYPe <Mode>
3.2.2.1 Simultaneous signal capture
Captures all data streams simultaneously. Measurements on more than one antenna
require a corresponding number of signal analyzers.
One of these analyzers acts as the master analyzer that controls the other analyzers.
Except for the master, you can include or exclude the analyzers from the test setup as
you like. When the slave analyzers capture data, they transfer this data to the master
for evaluation.
All analyzers have to be connected to the master via a LAN. Therefore, you have to
state the IP address for each analyzer in the setup in the "Simultaneous Signal
Capture Setup". You can enter the IP address via the numeric hardkeys or the online
keyboard that opens when you select the "Analyzer IP Address" field.
The setup allows you to assign antennas to an analyzer arbitrarily.
"Joined Rx Sync and Tracking" turns antenna synchronization and tracking on and off.
● On
Rx antennas are synchronized and tracked jointly.
● Off
Rx antennas are synchronized and tracked separately.
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R&S FSQ-K90/K91/K91n/K91ac Configuration
STC / MIMO Settings
Remote:
CONFigure:WLAN:ANTMatrix:ADDRess<analyzer> <IPAddress>
CONFigure:WLAN:ANTMatrix:ANTenna<analyzer> <Antenna>
CONFigure:WLAN:ANTMatrix:STATe<analyzer> <State>
CONFigure:WLAN:RSYNc:JOINed <State>
®
3.2.2.2 Sequential signal capture using an R&S
OSP switch box
Captures all data streams in a sequential order. Measurements on more than one
antenna require one signal analyzer and an R&S
®
R&S
OSP-B101. The data streams are captured sequentially, with each antenna being
®
OSP Switch Box, including option
connected to the switch box.
The analyzer and the switch box have to be connected via a LAN. State the IP Address
of the switch box in the corresponding input field.
®
The analyzer and DUT both have to be connected to the R&S
The module can be in one of three slots of the R&S
®
OSP. Select the slot the module is
OSP-B101 (module).
in from the "OSP Switch Module" dropdown menu.
®
The dialog box also contains a diagram that represents the R&S
OSP-B101 module.
This diagram shows you the way to connect the DUT antennas correctly to the switch
box.
● Cyan colored arrows represent the connections between the Tx antennas of the
DUT and the corresponding SMA plugs of the R&S
● Green colored arrows represent auxiliary connections of SMA plugs of the
● Yellow colored arrows represent the connection between the SMA plug of the
®
R&S
OSP-B101 option.
®
R&S
OSP-B101 option with the RF or analog baseband input of the analyzer.
®
OSP-B101 option.
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R&S FSQ-K90/K91/K91n/K91ac Configuration
For sequential MIMO
time! For example the signal field has to be identical for all
STC / MIMO Settings
measurements the DUT has to transmit identical PPDUs over
PPDUs.
IP address of the switch box
Depending of the switch box model, you can figure out its IP address as follows.
®
● In case of an R&S
display.
● In case of an R&S
IP address or use the default IP address of the OSP switch platform. For details
read the R&S
OSP130 switch platform, the IP address is shown in the front
®
OSP120 switch platform connect an external monitor to get the
®
OSP operation manual.
Remote:
CONFigure:WLAN:MIMO:OSP:ADDRess <IPAddress>
CONFigure:WLAN:MIMO:OSP:MODule <Module>
3.2.2.3 Sequential manual signal capture
Captures each data stream individually on one analyzer. Each antenna has to be
connected manually to the analyzer, before its data stream is captured.
The dialog box consists of four panels, each of which shows a preview of the capture
buffer recorded for one antenna (Rx 1 to Rx4).
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R&S FSQ-K90/K91/K91n/K91ac Configuration
For sequential MIMO measurements the DUT has to transmit identical PPDUs over
time! For example the signal field has to be identical for all
In case this condition is
reasonable measurement results!
STC / MIMO Settings
When you have connected an antenna to the R&S FSQ, press the "Capture" button.
The application then starts to capture that data stream. When the application is done
capturing the data, it shows the capture buffer in the corresponding preview panel, with
the detected PPDUs highlighted by green bars.
You can then proceed to connect the next antenna and capture the data stream of it.
Do this until all required data streams have been captured.
When you are done, press the "Analyze" button to perform the final analysis of all four
antennas. The application then shows the results in the usual manner in the main
result displays.
PPDUs.
not met, the subsequent procedure will not generate
Remote:
CONFigure:WLAN:MIMO:CAPTure:TYPe <Mode>
CONFigure:WLAN:MIMO:CAPTure <SignalPath>
CALCulate<1|2>:BURSt[:IMMediate]
Software Manual 1157.3135.42 - 08 88
R&S FSQ-K90/K91/K91n/K91ac Configuration
Advanced Settings
3.3 Advanced Settings
The "Advanced Settings" tab of the "General Settings" dialog box contains settings to
define the detailed measurement configuration of the signal analyzer.
► To select the "Advanced Settings" tab, set the focus on the tab (becomes blue)
and move the cursor to the left or right.
Fig. 20 Advanced Settings
The "Advanced Settings" tab contains the following sets of parameters.
● Advanced Baseband Settings on page 90
● Advanced Level Settings on page 95
● Peak Vector Error (IEEE) (IEEE 802.11b & g only) on page 99
Software Manual 1157.3135.42 - 08 89
R&S FSQ-K90/K91/K91n/K91ac Configuration
Advanced Settings
3.3.1 Advanced Baseband Settings
The "Advanced Baseband Settings" contain settings to configure the baseband input.
Available for measurements on the baseband input with R&S FSQ-B17 or -B71.
3.3.1.1 I/Q Input
Selects the impedance of the baseband input.
You can select an impedance of 50 Ω and 1 kΩ or 1 MΩ (depending on the device).
Available for the analog baseband input (R&S FSQ-B71).
Remote: INPut:IQ:IMPedance <Impedance>
3.3.1.2 I/Q Path
Selects the input path of baseband inputs.
You can use either a single input (I or Q) or both. In case of single inputs, Swap I/Q
becomes unavailable.
Available for the analog baseband input (R&S FSQ-B71).
Remote: INPut:IQ:TYPE <Path>
Software Manual 1157.3135.42 - 08 90
R&S FSQ-K90/K91/K91n/K91ac Configuration
Advanced Settings
3.3.1.3 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 the analog baseband input (R&S FSQ-B71).
Remote: INPut:IQ:BALanced[:STATe] <State>
3.3.1.4 Low Pass
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 the analog baseband input (R&S FSQ-B71).
Remote: [SENSe:]IQ:LPASs[:STATe] <State>
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R&S FSQ-K90/K91/K91n/K91ac Configuration
Advanced Settings
3.3.1.5 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 the analog baseband input (R&S FSQ-B71).
Remote: [SENSe:]IQ:DITHer[:STATe] <State>
3.3.1.6 ExIQ Box Settings
ExIQ Box Settings opens a dialog box to configure an ExIQ Box.
Available if an ExIQ Box is connected.
For more information refer to the documentation of the R&S ExIQ Box.
3.3.1.7 Input Sample Rate Auto
Turns automatic detection of the input sample rate on and off.
When you turn on automatic detection of the sample rate, the application determines
the sample rate from the LVDS interface. Otherwise, you have to define the sample
rate manually.
Available for the digital baseband input (R&S FSQ-B17).
Remote: INPut<1|2>:DIQ:SRATe:AUTO <State>
Software Manual 1157.3135.42 - 08 92
R&S FSQ-K90/K91/K91n/K91ac Configuration
Advanced Settings
3.3.1.8 Input Sample Rate
Defines the sampling rate of the I/Q data received from the digital baseband input.
In case it is not the sampling rate expected by the WLAN application, an internal
resampler resamples the data to the expected sample rate.
This allows measuring signals generated with slow I/Q-Mode, for example.
Available for the digital baseband input (R&S FSQ-B17).
Remote: INPut<1|2>:DIQ:SRATe <SampleRate>
3.3.1.9 Full Scale Level Auto
Turns automatic detection of the full scale level on and off.
When you turn on automatic detection of the full scale level, the application determines
the sample rate from the LVDS interface. Otherwise, you have to define the sample
rate manually.
Available for the digital baseband input (R&S FSQ-B17).
Remote: INPut<1|2>:DIQ:RANGe:AUTO <State>
Software Manual 1157.3135.42 - 08 93
R&S FSQ-K90/K91/K91n/K91ac Configuration
Advanced Settings
3.3.1.10 Full Scale Level
Defines the the expected voltage of the digital baseband input signal.
Available for the digital baseband input (R&S FSQ-B17).
If you change the full scale level in the "Advanced Settings", its value is automatically
adjusted in the "General Settings" tab.
Remote: INPut<1|2>:DIQ:RANGe[:UPPer] <Level>
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R&S FSQ-K90/K91/K91n/K91ac Configuration
Advanced Settings
3.3.2 Advanced Level Settings
The "Advanced Level Settings" contain settings to configure advanced level
characteristics.
3.3.2.1 Auto Level
Turns automatic detection of the ideal reference level on and off.
For more information see "Automatic Level Detection (Auto Level)".
This parameter is the same as the auto level in the "General Settings" tab.
Remote: CONFigure:POWer:AUTO <State> | ONCE
3.3.2.2 Auto Level Mode
Selects the method auto leveling is done with.
● Low Noise
Reduces the inherent noise as much as possible to determine the reference level.
● Low Distortion
Reduces the inherent spurious products as much as possible to determine the
reference level.
Available if "Auto Level" is on and for frequencies above 3.6 GHz. Otherwise the
setting is disabled and "Low Noise" is selected.
Remote: CONFigure:POWer:AUTO:MODE <Mode>
Software Manual 1157.3135.42 - 08 95
R&S FSQ-K90/K91/K91n/K91ac Configuration
Advanced Settings
3.3.2.3 Auto Level Time
Defines the measurement time for the auto leveling measurement.
Remote: CONFigure:POWer:AUTO:SWEep:TIME <Time>
3.3.2.4 Ref Level
Defines the reference level.
This parameter is the same as the reference level in the "General Settings" tab. For
more information see "Ref Level / Signal Level (RF Input)".
Available if auto leveling is turned off.
Remote: DISPlay[:WINDow]:TRACe:Y[:SCALe]:RLEVel[:RF] <Level>
3.3.2.5 RF Att
Defines the attenuation of the mechanical attenuator.
Available if auto leveling is turned off.
If you are using auto leveling, RF attenuation is coupled to the reference level.
Otherwise, the attenuation is independent from the reference level and can be defined
manually.
Remote: INPut:ATTenuation <Attenuation>
Software Manual 1157.3135.42 - 08 96
R&S FSQ-K90/K91/K91n/K91ac Configuration
Advanced Settings
3.3.2.6 Electronic Attenuation (El Att)
Defines the characteristics of electronic attenuation.
● Mode
Selects manual or automatic control of the electronic attenuator.
● State
Turns the electronic attenuator on and off (for Mode = manual).
● Settings
Defines the attenuation of the electronic attenuator.
Electronic attenuation is available if the frequency allows the use of the electronic
attenuator and if the electronic attenuator has been installed.
Remote: INPut:EATT:AUTO <State>
3.3.2.7 YIG Filter
Defines the characteristics of the YIG filter.
● Mode
Selects manual or automatic control of the YIG filter.
● State
Turns the YIG filter on and of (for Mode = manual).
Remote: INPut:FILTer:YIG[:STATe] <State>
Software Manual 1157.3135.42 - 08 97
R&S FSQ-K90/K91/K91n/K91ac Configuration
For input sample rates greater than
Extension
Advanced Settings
3.3.2.8 Input Sample Rate
Defines the sampling rate applied to I/Q measurements.
40 MHz, option R&S FSQ-B72 Bandwidth
is required.
● In case of IEEE 802.11a measurements, the input sample rate can be defined
continuously.
● In case of IEEE 802.11n measurements, the input sample rate is a discrete set
(20 MHz, 40 MHz, 80 MHz).
● In case of IEEE 802.11ac measurements, the input sample rate is a discrete set
(20 MHz, 40 MHz, 80 MHz, 160 MHz)
Remote: TRACe:IQ:SRATe <SampleRate>
3.3.2.9 High Dynamic
Turns the bypass of the bandwidth extension R&S FSQ-B72 on and off if you are using
a wideband filter. The signal instead passes through the normal signal path.
If active, high dynamic results in a higher resolution because the normal signal path
uses a 14-bit ADC. However, all signals to the left or right of the spectrum of interest
are folded into the spectrum itself.
The high dynamic functionality is available only if R&S FSQ-B72 is installed and the
sample rate is in the range from 20.4 MHz to 40.8 MHz.
High dynamics is automatically turned on if option R&S FSQ-B72 is installed, and the
sample rate is set between 20.4 MHz and 40.8 MHz.
Remote: TRACE:IQ:FILTer:FLATness <Filter>
Software Manual 1157.3135.42 - 08 98
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