®
R&S
FSW I/Q Analyzer and I/Q Input
Interfaces
User Manual
(;ÙÎa2)
1175644902
Version 39
This manual applies to the following R&S®FSW models with firmware version 5.10 and later:
●
R&S®FSW8 (1331.5003K08 / 1312.8000K08)
●
R&S®FSW13 (1331.5003K13 / 1312.8000K13)
●
R&S®FSW26 (1331.5003K26 / 1312.8000K26)
●
R&S®FSW43 (1331.5003K43 / 1312.8000K43)
●
R&S®FSW50 (1331.5003K50 / 1312.8000K50)
●
R&S®FSW67 (1331.5003K67 / 1312.8000K67)
●
R&S®FSW85 (1331.5003K85 / 1312.8000K85)
© 2022 Rohde & Schwarz GmbH & Co. KG
Muehldorfstr. 15, 81671 Muenchen, Germany
Phone: +49 89 41 29 - 0
Email: info@rohde-schwarz.com
Internet: www.rohde-schwarz.com
Subject to change – data without tolerance limits is not binding.
R&S® is a registered trademark of Rohde & Schwarz GmbH & Co. KG.
Trade names are trademarks of the owners.
1175.6449.02 | Version 39 | R&S®FSW I/Q Analyzer and I/Q Input
Throughout this manual, products from Rohde & Schwarz are indicated without the ® symbol, e.g. R&S®FSW is indicated as
R&S FSW. R&S®FSW Multi-Standard Radio Analyzer is indicated as R&S FSW MSRA. Products of the R&S®SMW family, e.g.
R&S®SMW200A, are indicated as R&S SMW.
R&S®FSW I/Q Analyzer and I/Q Input
Contents
1 Documentation overview.......................................................................7
1.1 Getting started manual................................................................................................. 7
1.2 User manuals and help.................................................................................................7
1.3 Service manual..............................................................................................................7
1.4 Instrument security procedures.................................................................................. 8
1.5 Printed safety instructions...........................................................................................8
1.6 Data sheets and brochures.......................................................................................... 8
1.7 Release notes and open-source acknowledgment (OSA).........................................8
1.8 Application notes, application cards, white papers, etc........................................... 8
2 Welcome to the I/Q Analyzer application.............................................9
Contents
2.1 Starting the I/Q Analyzer application.........................................................................11
2.2 Understanding the display information.................................................................... 12
3 Typical applications for the I/Q analyzer and I/Q input.....................15
4 Measurement and result displays...................................................... 16
5 Basics on I/Q data acquisition and processing................................ 21
5.1 Processing analog I/Q data from RF input............................................................... 22
5.2 Processing data from the Digital Baseband interface.............................................43
5.3 Processing data from the Analog Baseband interface............................................50
5.4 Processing Oscilloscope Baseband Input............................................................... 57
5.5 Using probes............................................................................................................... 61
5.6 Basics on external mixers..........................................................................................67
5.7 Basics on external generator control........................................................................74
5.8 Basics on input from I/Q data files............................................................................ 86
5.9 Basics on the 2 GHz / 5 GHz bandwidth extensions (R&S FSW-B2000/B5000
options)........................................................................................................................ 87
5.10 Digital I/Q 40G streaming output............................................................................... 97
5.11 IF and video signal output........................................................................................100
5.12 Receiving and providing trigger signals.................................................................102
5.13 I/Q data import and export....................................................................................... 103
5.14 Basics on FFT............................................................................................................104
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5.15 I/Q analyzer in MSRA/MSRT operating mode......................................................... 110
5.16 Measurements in the time and frequency domain................................................. 111
6 Configuration......................................................................................113
6.1 Configuration overview............................................................................................ 113
6.2 Import/export functions............................................................................................ 115
6.3 Data input and output settings................................................................................ 119
6.4 Amplitude...................................................................................................................172
6.5 Frequency settings................................................................................................... 182
6.6 Trigger settings......................................................................................................... 184
6.7 Data acquisition and bandwidth settings............................................................... 194
6.8 Display configuration............................................................................................... 204
6.9 Adjusting settings automatically.............................................................................204
Contents
6.10 Configuring an I/Q analyzer as an MSRA/MSRT secondary application............. 207
7 Analysis.............................................................................................. 209
7.1 Trace settings............................................................................................................209
7.2 Spectrogram settings............................................................................................... 214
7.3 Trace / data export configuration............................................................................ 219
7.4 Marker usage............................................................................................................. 223
7.5 Analysis in MSRA/MSRT mode................................................................................250
8 How to work with I/Q data................................................................. 252
8.1 How to perform measurements in the I/Q Analyzer application...........................252
8.2 How to capture or output I/Q data via optional interfaces.................................... 254
8.3 How to export and import I/Q data.......................................................................... 266
9 Measurement example: Providing I/Q data from the I/Q Analyzer to
a signal generator.............................................................................. 269
10 Troubleshooting the measurement.................................................. 274
10.1 Error messages......................................................................................................... 274
11 Remote commands to perform measurements with I/Q data........ 278
11.1 Introduction............................................................................................................... 279
11.2 Common suffixes......................................................................................................283
11.3 Activating I/Q Analyzer measurements...................................................................284
11.4 Configuring I/Q Analyzer measurements................................................................290
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11.5 Configuring the result display................................................................................. 422
11.6 Capturing data and performing sweeps................................................................. 431
11.7 I/Q Analysis................................................................................................................437
11.8 Retrieving results......................................................................................................502
11.9 Importing and exporting I/Q data and results........................................................ 514
11.10 Querying the status registers.................................................................................. 516
11.11 Programming examples........................................................................................... 522
11.12 Deprecated commands.............................................................................................530
Annex.................................................................................................. 531
A Description of the LVDS connector..................................................531
B Formats for returned values: ASCII format and binary format...... 533
Contents
C Reference: format description for I/Q data files..............................534
D Reference: supported I/Q file formats..............................................536
D.1 I/Q data file format (iq-tar)........................................................................................ 537
D.2 CSV file format.......................................................................................................... 545
D.3 IQW file format...........................................................................................................548
D.4
Matlab® v. 4 / v. 7.3 file format.................................................................................. 549
D.5 AID format..................................................................................................................552
D.6 WV format.................................................................................................................. 562
List of commands (I/Q Analyzer+I/Q input interfaces (B17+B71)).563
Index....................................................................................................574
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Contents
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R&S®FSW I/Q Analyzer and I/Q Input
1 Documentation overview
This section provides an overview of the R&S FSW user documentation. Unless specified otherwise, you find the documents on the R&S FSW product page at:
www.rohde-schwarz.com/manual/FSW
1.1 Getting started manual
Introduces the R&S FSW and describes how to set up and start working with the product. Includes basic operations, typical measurement examples, and general information, e.g. safety instructions, etc.
A printed version is delivered with the instrument. A PDF version is available for download on the Internet.
Documentation overview
Service manual
1.2 User manuals and help
Separate user manuals are provided for the base unit and the firmware applications:
●
Base unit manual
Contains the description of all instrument modes and functions. It also provides an
introduction to remote control, a complete description of the remote control commands with programming examples, and information on maintenance, instrument
interfaces and error messages. Includes the contents of the getting started manual.
●
Firmware application manual
Contains the description of the specific functions of a firmware application, including remote control commands. Basic information on operating the R&S FSW is not
included.
The contents of the user manuals are available as help in the R&S FSW. The help
offers quick, context-sensitive access to the complete information for the base unit and
the firmware applications.
All user manuals are also available for download or for immediate display on the Internet.
1.3 Service manual
Describes the performance test for checking the rated specifications, module replacement and repair, firmware update, troubleshooting and fault elimination, and contains
mechanical drawings and spare part lists.
The service manual is available for registered users on the global Rohde & Schwarz
information system (GLORIS):
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R&S®FSW I/Q Analyzer and I/Q Input
https://gloris.rohde-schwarz.com
1.4 Instrument security procedures
Deals with security issues when working with the R&S FSW in secure areas. It is available for download on the Internet.
1.5 Printed safety instructions
Provides safety information in many languages. The printed document is delivered with
the product.
1.6 Data sheets and brochures
Documentation overview
Application notes, application cards, white papers, etc.
The data sheet contains the technical specifications of the R&S FSW. It also lists the
firmware applications and their order numbers, and optional accessories.
The brochure provides an overview of the instrument and deals with the specific characteristics.
See www.rohde-schwarz.com/brochure-datasheet/FSW
1.7 Release notes and open-source acknowledgment (OSA)
The release notes list new features, improvements and known issues of the current
firmware version, and describe the firmware installation.
The open-source acknowledgment document provides verbatim license texts of the
used open source software.
See www.rohde-schwarz.com/firmware/FSW
1.8 Application notes, application cards, white papers, etc.
These documents deal with special applications or background information on particular topics.
See www.rohde-schwarz.com/application/FSW
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R&S®FSW I/Q Analyzer and I/Q Input
2 Welcome to the I/Q Analyzer application
The R&S FSW I/Q Analyzer is a firmware application that adds functionality to perform
I/Q data acquisition and analysis to the R&S FSW.
The R&S FSW I/Q Analyzer features:
●
Acquisition of analog I/Q data
●
Optionally, acquisition of digital I/Q data via the optional "Digital Baseband" interface
●
Optionally, acquisition of analog baseband data via the optional "Analog Baseband"
interface
●
Import of stored I/Q data from other applications
●
Spectrum, magnitude, I/Q vector and separate I and Q component analysis of any
I/Q data on the instrument
●
Export of I/Q data to other applications
●
Optionally, direct output of digital I/Q data via the optional "Digital Baseband" interface
Welcome to the I/Q Analyzer application
Described options
In addition to the base unit, the following options are described:
Option Description
R&S®FSW-B10 (1313.1622.02) External generator control
R&S®FSW-B13 (1313.0761.02) High-pass filter
R&S®FSW-B17 (1313.0784.02) "Digital Baseband" interface
R&S®FSW-B21 (1313.1100.XX) External mixer
R&S®FSW-B24 (1313.0832.XX) Preamplifier
R&S®FSW-B25 (1313.0990.02) Electronic attenuator
R&S®FSW-B71 (1313.1651.XX,
1313.6547.02) / R&S®FSW-B2071
(1331.8302.XX)
R&S®FSW-B106 (1331.6451.02) / I/Q memory extension 6 GHz
R&S®FSW-B108 (1331.6751.02) / I/Q memory extension 8 GHz
R&S®FSW-B124 (1338.5273.02) I/Q memory extension 24 GHz
R&S®FSW-B517 (1331.6980.02) /
R&S®FSW-B1017 (1350.7008.02)
"Analog Baseband" interface
Digital I/Q 40G streaming output
R&S®FSW-B40 (1313.0861.02) /
R&S®FSW-U40 (1313.52505.02)
R&S®FSW-B80 (1313.0878.02) /
R&S®FSW-U80 (1313.5211.02)
Bandwidth extension 40 MHz
Bandwidth extension 80 MHz
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R&S®FSW I/Q Analyzer and I/Q Input
Option Description
Welcome to the I/Q Analyzer application
R&S®FSW-B160 (1313.1668.02 /
1325.4850.04) / R&S®FSW-U160
(1313.3754.02 / 1325.5357.04)
R&S®FSW-B320 (1313.7172.02 /
1325.4867.04) / R&S®FSW-U320
(1313.7189.02)
R&S®FSW-B512 (1313.4296.xx) /
R&S®FSW-U512 (1321.6320.xx)
R&S®FSW-B1200 (1331.6400.xx) Bandwidth extension 1.2 GHz
R&S®FSW-B2000 (1325.4750.xx) /
R&S®FSW-U2000 (1325.5405.xx)
R&S®FSW-B2001 (1331.6916.xx) /
R&S®FSW-U2001 (1331.7070.xx)
R&S®FSW-B4001 (1338.5215.xx) /
R&S®FSW-U4001 (1338.5244.xx)
R&S®FSW-B5000 (1331.6997.xx) /
R&S®FSW-U5000 (1331.7629.xx)
R&S®FSW-B6001 (1338.5221.xx) /
R&S®FSW-U6001 (1338.5250.xx)
Bandwidth extension 160 MHz
Bandwidth extension 320 MHz
Bandwidth extension 512 MHz
Bandwidth extension 2 GHz (external)
Bandwidth extension 2 GHz
Bandwidth extension 4 GHz
Bandwidth extension 5 GHz (external)
Bandwidth extension 6 GHz
R&S®FSW-B8001 (1338.5238.xx) /
R&S®FSW-U8001 (1338.5267.xx)
Bandwidth extension 8 GHz
This user manual contains a description of the functionality that the application provides, including remote control operation.
All functions not discussed in this manual are the same as in the base unit and are
described in the R&S FSW User Manual. The latest version is available for download
at the product homepage http://www.rohde-schwarz.com/product/FSW.
Additional information
Several application notes discussing I/Q analysis are available from the Rohde &
Schwarz website:
1EF85: Converting R&S I/Q data files
1EF92: Wideband Signal Analysis
1MA257: Wideband mm-Wave Signal Generation and Analysis
1EF84: Differential measurements with Spectrum Analyzers and Probes
Installation
The R&S FSW I/Q Analyzer application is part of the standard base unit and requires
no further installation.
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R&S®FSW I/Q Analyzer and I/Q Input
The optional "Digital Baseband" interface requires both hardware and firmware installation, which is described in the release notes provided with the option at delivery.
2.1 Starting the I/Q Analyzer application
The I/Q Analyzer is an application on the R&S FSW.
To activate the I/Q Analyzer application
1. Select the [MODE] key.
A dialog box opens that contains all applications currently available on your
R&S FSW.
2. Select the "I/Q Analyzer" item.
Welcome to the I/Q Analyzer application
Starting the I/Q Analyzer application
The R&S FSW opens a new channel for the I/Q Analyzer application.
The measurement is started immediately with the default settings.
It can be configured in the I/Q Analyzer "Overview" dialog box, which is displayed
when you select the "Overview" softkey from any menu (see Chapter 6.1, "Configura-
tion overview", on page 113).
Multiple Channels and Sequencer Function
When you activate an application, a new channel is created which determines the
measurement settings for that application (channel). The same application can be activated with different measurement settings by creating several channels for the same
application.
The number of channels that can be configured at the same time depends on the available memory on the instrument.
Only one measurement can be performed at any time, namely the one in the currently
active channel. However, in order to perform the configured measurements consecutively, a Sequencer function is provided.
If activated, the measurements configured in the currently defined channels are performed one after the other in the order of the tabs. The currently active measurement is
indicated by a
symbol in the tab label.
The result displays of the individual channels are updated in the tabs (as well as the
"MultiView") as the measurements are performed. Sequential operation itself is independent of the currently displayed tab.
For details on the Sequencer function see the R&S FSW User Manual.
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R&S®FSW I/Q Analyzer and I/Q Input
2.2 Understanding the display information
The following figure shows a measurement diagram during I/Q Analyzer operation. All
different information areas are labeled. They are explained in more detail in the following sections.
Welcome to the I/Q Analyzer application
Understanding the display information
1
2 3 4
56
Figure 2-1: Screen elements in the I/Q Analyzer application
1+4 = Window title bar with diagram-specific (trace) information
2 = Channel bar for firmware and measurement settings
3 = Diagram area
5 = Diagram footer with diagram-specific information, depending on result display
6 = Instrument status bar with error messages and date/time display
MSRA/MSRT operating mode
In MSRA and MSRT operating mode, additional tabs and elements are available. A
colored background of the screen behind the channel tabs indicates that you are in
MSRA/MSRT operating mode.
For details on the MSRA operating mode see the R&S FSW MSRA User Manual. For
details on the MSRT operating mode see the R&S FSW Realtime Spectrum Application and MSRT Operating Mode User Manual.
Channel bar information
In the I/Q Analyzer application, the R&S FSW shows the following settings:
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R&S®FSW I/Q Analyzer and I/Q Input
Table 2-1: Information displayed in the channel bar for the I/Q Analyzer application
Ref Level Reference level
(m.+el.)Att (Mechanical and electronic) RF attenuation
Ref Offset Reference level offset
Freq Center frequency
Meas Time Measurement time
Rec Length Defined record length (number of samples to capture)
SRate Defined sample rate for data acquisition
RBW (Spectrum evaluation only) Resolution bandwidth calculated from the
Inp:Dig-IQ Input source: digital I/Q data from the optional "Digital Baseband" inter-
Inp:Analog <I/Q mode> Input source: analog baseband data from the optional "Analog Baseband"
Welcome to the I/Q Analyzer application
Understanding the display information
sample rate and record length
face
interface
<I/Q mode>: defines the processing mode (see Chapter 5.3.3, "I/Q pro-
cessing modes", on page 53)
200 MHz The 200 MHz filter for wideband processing is active (see "200 MHz Filter"
on page 197)
Low Noise Signal processing is optimized for low noise (rather than low distortion,
see "Optimization" on page 176)
In addition, the channel bar also displays information on instrument settings that affect
the measurement results even though this is not immediately apparent from the display
of the measured values (e.g. transducer or trigger settings). This information is displayed only when applicable for the current measurement.
For details see the R&S FSW Getting Started manual.
Window title bar information
For each diagram, the header provides the following information:
4
1
Figure 2-2: Window title bar information in the I/Q Analyzer application
1 = Window number
2 = Window type
3 = Trace color
4 = Trace number
5 = Detector
6 = Trace mode
2 3
5 6
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R&S®FSW I/Q Analyzer and I/Q Input
Diagram footer information
The information in the diagram footer (beneath the diagram) depends on the evaluation:
●
Center frequency
●
Number of sweep points
●
Range per division (x-axis)
●
Span (Spectrum)
Status bar information
Global instrument settings, the instrument status and any irregularities are indicated in
the status bar beneath the diagram.
Furthermore, the progress of the current operation is displayed in the status bar.
For details see Chapter 10.1, "Error messages", on page 274.
Welcome to the I/Q Analyzer application
Understanding the display information
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R&S®FSW I/Q Analyzer and I/Q Input
3 Typical applications for the I/Q analyzer and
I/Q input
Baseband signals mostly occur as so-called complex baseband signals, i.e. a signal
representation that consists of two channels; the "in phase" (I) and the "quadrature"
(Q) channel. Such signals are referred to as I/Q signals. I/Q signals are useful because
the specific RF or IF frequencies are not needed. The complete modulation information
and even distortion that originates from the RF, IF or baseband domains can be analyzed in the I/Q baseband. Thus, the I/Q Analyzer is ideal for analyzing I/Q baseband
signals.
The optional "Digital Baseband" interface can be used to capture or output the I/Q
data.
The following typical applications use the "Digital Baseband" interface:
●
Capturing and evaluating digital I/Q data in the I/Q Analyzer application of the
R&S FSW base unit or other (optional) applications, e.g. R&S FSW-K70 (VSA).
See also the description of the individual applications.
Typical applications for the I/Q analyzer and I/Q input
●
Output of digital I/Q data to a selected receiver, e.g. to implement fading (simulating mobile radio communication participants) using a generator.
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R&S®FSW I/Q Analyzer and I/Q Input
4 Measurement and result displays
Access: "Overview" > "Display Config"
Or: [MEAS] > "Display Config"
The I/Q Analyzer can capture I/Q data. The I/Q data that was captured by or imported
to the R&S FSW can then be evaluated in various different result displays. Select the
result displays using the SmartGrid functions.
Up to 6 evaluations can be displayed in the I/Q Analyzer at any time, including several
graphical diagrams, marker tables or peak lists.
For details on working with the SmartGrid see the R&S FSW Getting Started manual.
Measurements in the time and frequency domain
The I/Q Analyzer secondary application (not primary) in MSRA mode can also perform
measurements on the captured I/Q data in the time and frequency domain (see also
Chapter 5.15, "I/Q analyzer in MSRA/MSRT operating mode", on page 110). They are
configured using the same settings and provide similar results. In addition, the analysis
interval used for the measurement is indicated as in all multistandard applications.
Measurement and result displays
The time and frequency domain measurements and the available results are described
in detail in the R&S FSW User Manual.
Result displays for I/Q data:
Magnitude..................................................................................................................... 16
Spectrum.......................................................................................................................17
I/Q-Vector......................................................................................................................17
Real/Imag (I/Q)..............................................................................................................18
Phase vs. Time..............................................................................................................18
Marker Table................................................................................................................. 19
Marker Peak List........................................................................................................... 19
I/Q 40G Recording........................................................................................................ 20
Magnitude
Shows the level values in time domain.
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R&S®FSW I/Q Analyzer and I/Q Input
Remote command:
LAY:ADD:WIND? '1',RIGH,MAGN, see LAYout:ADD[:WINDow]? on page 424
Results:
TRACe<n>[:DATA]? on page 507
Spectrum
Displays the frequency spectrum of the captured I/Q samples.
Measurement and result displays
The specified Analysis Bandwidth is indicated by vertical blue lines.
Remote command:
LAY:ADD:WIND? '1',RIGH,FREQ, see LAYout:ADD[:WINDow]? on page 424
Results:
TRACe<n>[:DATA]? on page 507
I/Q-Vector
Displays the captured samples in an I/Q-plot. The samples are connected by a line.
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R&S®FSW I/Q Analyzer and I/Q Input
Note: For the I/Q vector result display, the number of I/Q samples to record ("Record
Length") must be identical to the number of trace points to be displayed ("Sweep
Points"; for I/Q Analyzer: 10001). For record lengths outside the valid range of sweep
points the diagram does not show valid results.
For input from the optional "Analog Baseband" interface in real baseband mode, the
I/Q vector is a constant line (as one component is 0 for all sweep points).
For more information see Chapter 5.3.3, "I/Q processing modes", on page 53.
Remote command:
LAY:ADD:WIND? '1',RIGH,VECT, see LAYout:ADD[:WINDow]? on page 424
Results:
TRACe<n>[:DATA]? on page 507
Real/Imag (I/Q)
Displays the I and Q values in separate diagrams.
Measurement and result displays
Note: For analog baseband input in Real Baseband mode, only one diagram is dis-
played (for the selected component).
For details, see "Real baseband mode (I or Q only)" on page 54.
Remote command:
LAY:ADD:WIND? '1',RIGH,RIM, see LAYout:ADD[:WINDow]? on page 424
Results:
TRACe<n>[:DATA]? on page 507
Phase vs. Time
Shows the phase values in the time domain.
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R&S®FSW I/Q Analyzer and I/Q Input
Measurement and result displays
Remote command:
LAY:ADD? '1',RIGH, PHASe, see LAYout:ADD[:WINDow]? on page 424
Marker Table
Displays a table with the current marker values for the active markers.
This table is displayed automatically if configured accordingly.
(See "Marker Table Display" on page 227).
Tip: To navigate within long marker tables, simply scroll through the entries with your
finger on the touchscreen.
Remote command:
LAY:ADD? '1',RIGH, MTAB, see LAYout:ADD[:WINDow]? on page 424
Results:
CALCulate<n>:MARKer<m>:X on page 460
CALCulate<n>:MARKer<m>:Y? on page 513
Marker Peak List
The marker peak list determines the frequencies and levels of peaks in the spectrum or
time domain. How many peaks are displayed can be defined, as well as the sort order.
In addition, the detected peaks can be indicated in the diagram. The peak list can also
be exported to a file for analysis in an external application.
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R&S®FSW I/Q Analyzer and I/Q Input
Tip: To navigate within long marker peak lists, simply scroll through the entries with
your finger on the touchscreen.
Remote command:
LAY:ADD? '1',RIGH, PEAK, see LAYout:ADD[:WINDow]? on page 424
Results:
CALCulate<n>:MARKer<m>:X on page 460
CALCulate<n>:MARKer<m>:Y? on page 513
Measurement and result displays
I/Q 40G Recording
During a running I/Q data output recording, you can add marker information to the data
stream at a user-definable time by selecting a button. The "I/Q 40G Recording" window
provides such a button that remains visible throughout the measurement, without having to open a dialog box. Thus, you can insert a marker at any time during the measurement.
For more information, see Chapter 5.10, "Digital I/Q 40G streaming output",
on page 97.
Remote command:
OUTPut<up>:IQHS:MARKer on page 385
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R&S®FSW I/Q Analyzer and I/Q Input
5 Basics on I/Q data acquisition and process-
ing
Some background knowledge on basic terms and principles used when describing I/Q
data acquisition on the R&S FSW in general, and in the I/Q Analyzer application in particular, is provided here for a better understanding of the required configuration settings.
The I/Q Analyzer provides various possibilities to acquire the I/Q data to be analyzed:
●
Capturing analog I/Q data from the "RF Input" connector
●
Capturing digital I/Q data from the optional "Digital Baseband" interface
●
Capturing analog I/Q data from the optional "Analog Baseband" interface, for
example from active probes
●
Capturing analog I/Q data from the optional "Analog Baseband" interface and redirecting it to the RF input path
●
Capturing analog I/Q data via the channel input of a connected oscilloscope and
transferring the data to the R&S FSW via LAN
●
Importing I/Q data from a file
Basics on I/Q data acquisition and processing
Background information for all these scenarios and more is provided in the following
sections.
● Processing analog I/Q data from RF input..............................................................22
● Processing data from the Digital Baseband interface............................................. 43
● Processing data from the Analog Baseband interface............................................50
● Processing Oscilloscope Baseband Input...............................................................57
● Using probes...........................................................................................................61
● Basics on external mixers....................................................................................... 67
● Basics on external generator control.......................................................................74
● Basics on input from I/Q data files.......................................................................... 86
● Basics on the 2 GHz / 5 GHz bandwidth extensions (R&S FSW-B2000/B5000
options)................................................................................................................... 87
● Digital I/Q 40G streaming output.............................................................................97
● IF and video signal output.....................................................................................100
● Receiving and providing trigger signals................................................................ 102
● I/Q data import and export.................................................................................... 103
● Basics on FFT.......................................................................................................104
● I/Q analyzer in MSRA/MSRT operating mode.......................................................110
● Measurements in the time and frequency domain.................................................111
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R&S®FSW I/Q Analyzer and I/Q Input
5.1 Processing analog I/Q data from RF input
Complex baseband data
In the telephone systems of the past, baseband data was transmitted unchanged as an
analog signal. In modern phone systems and in radio communication, however, the
baseband data is modulated on a carrier frequency, which is then transmitted. The
receiver must demodulate the data based on the carrier frequency. When using modern modulation methods (e.g. QPSK, QAM etc.), the baseband signal becomes complex. Complex data (or: I/Q data) consists of an imaginary (I) and a real (Q) component.
Sweep vs sampling
The standard Spectrum application on the R&S FSW performs frequency sweeps on
the input signal and measurements in the frequency and time domain. Other applications on the R&S FSW, such as the I/Q Analyzer, sample and process the individual I
and Q components of the complex signal.
Basics on I/Q data acquisition and processing
Processing analog I/Q data from RF input
I/Q Analyzer - processing complex data from RF input
The I/Q Analyzer is a standard application used to capture and analyze I/Q data on the
R&S FSW. By default, it assumes the I/Q data is modulated on a carrier frequency and
input via the "RF Input" connector on the R&S FSW.
The A/D converter samples the IF signal at a rate of 200 MHz. The digital signal is
down-converted to the complex baseband, lowpass-filtered, and the sample rate is
reduced. The analog filter stages in the analyzer cause a frequency response which
adds to the modulation errors. An equalizer filter before the resampler compensates
for this frequency response. The continuously adjustable sample rates are realized
using an optimal decimation filter and subsequent resampling on the set sample rate.
A dedicated memory (capture buffer) is available in the R&S FSW for a maximum of
400 Msamples (400*1000*1000) of complex samples (pairs of I and Q data). The number of complex samples to be captured can be defined (for restrictions refer to Chap-
ter 5.1.1, "Sample rate and maximum usable I/Q bandwidth for RF input",
on page 24).
The block diagram in Figure 5-1 shows the analyzer hardware from the IF section to
the processor.
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R&S®FSW I/Q Analyzer and I/Q Input
Basics on I/Q data acquisition and processing
Processing analog I/Q data from RF input
Figure 5-1: Block diagram illustrating the R&S FSW signal processing for analog I/Q data (without
Figure 5-2: Block diagram illustrating the R&S FSW signal processing for analog I/Q data (with option
bandwidth extension options)
B160)
Figure 5-3: Block diagram illustrating the R&S FSW signal processing for analog I/Q data (with option
B320)
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R&S®FSW I/Q Analyzer and I/Q Input
Basics on I/Q data acquisition and processing
Processing analog I/Q data from RF input
Figure 5-4: Block diagram illustrating the R&S FSW signal processing for analog I/Q data (with option
B512)
5.1.1 Sample rate and maximum usable I/Q bandwidth for RF input
Definitions
●
Input sample rate (ISR): the sample rate of the useful data provided by the device
connected to the input of the R&S FSW
●
(User, Output) Sample rate (SR): the user-defined sample rate (e.g. in the "Data
Acquisition" dialog box in the "I/Q Analyzer" application) which is used as the basis
for analysis or output
●
Usable I/Q (analysis) bandwidth: the bandwidth range in which the signal
remains undistorted in regard to amplitude characteristic and group delay; this
range can be used for accurate analysis by the R&S FSW
●
Record length: the number of I/Q samples to capture during the specified measurement time; calculated as the measurement time multiplied by the sample rate
For the I/Q data acquisition, digital decimation filters are used internally in the
R&S FSW. The passband of these digital filters determines the maximum usable I/Q
bandwidth. In consequence, signals within the usable I/Q bandwidth (passband)
remain unchanged, while signals outside the usable I/Q bandwidth (passband) are
suppressed. Usually, the suppressed signals are noise, artifacts, and the second IF
sideband. If frequencies of interest to you are also suppressed, try to increase the output sample rate, which increases the maximum usable I/Q bandwidth.
Bandwidth extension options
You can extend the maximum usable I/Q bandwidth provided by the R&S FSW in the
basic installation by adding options. These options can either be included in the initial
installation (B-options) or updated later (U-options). The maximum bandwidth provided
by the individual option is indicated by its number, for example, B40 extends the bandwidth to 40 MHz.
Note that the U-options as of U40 always require all lower-bandwidth options as a prerequisite, while the B-options already include them.
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R&S®FSW I/Q Analyzer and I/Q Input
As a rule, the usable I/Q bandwidth is proportional to the output sample rate. Yet, when
the I/Q bandwidth reaches the bandwidth of the analog IF filter (at very high output
sample rates), the curve breaks.
● Available bandwidth extension options................................................................... 25
● Relationship between sample rate, record length and usable I/Q bandwidth......... 26
● R&S FSW without additional bandwidth extension options.................................... 28
● R&S FSW with I/Q bandwidth extension option B40 or U40...................................28
● R&S FSW with I/Q bandwidth extension option B80 or U80...................................29
● R&S FSW with activated I/Q bandwidth extension option B160 or U160............... 29
● R&S FSW with activated I/Q bandwidth extension option B320/U320................... 30
● R&S FSW with activated I/Q bandwidth extension option B512............................. 31
● R&S FSW with activated I/Q bandwidth extension option B1200........................... 33
● R&S FSW with activated I/Q bandwidth extension option B2001........................... 36
● R&S FSW with activated I/Q bandwidth extension option B2000........................... 38
● R&S FSW with activated I/Q bandwidth extension option B5000........................... 40
● R&S FSW with activated I/Q bandwidth extension option B4001/B6001/B8001.... 41
5.1.1.1 Available bandwidth extension options
Basics on I/Q data acquisition and processing
Processing analog I/Q data from RF input
Table 5-1: Available bandwidth extension options
Max. usable
I/Q bandwidth
28 MHz - -
40 MHz B40 U40
80 MHz B80 U40+U80 or
160 MHz B160 U40+U80+U160 or
320 MHz B320 U40+U80+U160+U320 or
512 MHz B512 U40+U80+U512 or
1200 MHz B1200 B40 + U80 + U1200 or
Required B-option Required U-options
B40+U80
B40+U80+U160 or
B80+U160
B40+U80+U160+U320 or
B80+U160+U320 or
B160+U320
B40+U80+U512 or
B80+U512 or
B80 + U1200
2000 MHz B2000 U2000
2000 MHz B2001 U2001
4000 MHz B4001 U4001
5000 MHz B5000 U5000
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R&S®FSW I/Q Analyzer and I/Q Input
Basics on I/Q data acquisition and processing
Processing analog I/Q data from RF input
Max. usable
I/Q bandwidth
6000 MHz B6001 U6001
8000 MHz B8001 U8001
Required B-option Required U-options
5.1.1.2 Relationship between sample rate, record length and usable I/Q bandwidth
Up to the maximum bandwidth, the following rule applies:
Usable I/Q bandwidth = 0.8 * Output sample rate
Regarding the record length, the following rule applies:
Record length = Measurement time * sample rate
Maximum record length for RF input
The maximum record length, that is, the maximum number of samples that can be captured, depends on the sample rate.
For activated option B320 or U320, see Table 5-9.
For activated option -B512, see Table 5-11.
For activated option B1200, see Table 5-13.
For activated option B2001, see Chapter 5.1.1.10, "R&S FSW with activated I/Q band-
width extension option B2001", on page 36.
For activated option B2000, see Chapter 5.1.1.11, "R&S FSW with activated I/Q band-
width extension option B2000", on page 38.
For activated option B5000, see Chapter 5.1.1.12, "R&S FSW with activated I/Q band-
width extension option B5000", on page 40.
For activated option B4001/B6001/B8001, see Chapter 5.1.1.13, "R&S FSW with acti-
vated I/Q bandwidth extension option B4001/B6001/B8001", on page 41.
Table 5-2: Maximum record length (without I/Q bandwidth extension options R&S
Sample rate Maximum record length
100 Hz to 200 MHz 440 Msamples
200 MHz to 20 GHz
(upsampling)
B512/-B1200/-B2001/-B4001/-B6001/-B8001)
220 Msamples
FSW-B160/-B320/-
The Figure 5-5 shows the maximum usable I/Q bandwidths depending on the output
sample rates.
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R&S®FSW I/Q Analyzer and I/Q Input
Usable I/Q
bandwidth
I/Q bandwidths for RF input
[MHz]
160
150
140
130
120
110
100
Wideband
board:
BW = 0.80
* f
out
Basics on I/Q data acquisition and processing
Processing analog I/Q data from RF input
Activated option
B160 / U160
90
80
70
60
50
40
30
28
20
10
20 40
Figure 5-5: Relationship between maximum usable I/Q bandwidth and output sample rate with and
Restricting the maximum bandwidth manually
By default, all installed bandwidth extension options are activated, allowing for the
maximum bandwidth for measurements on the R&S FSW. However, sometimes the
maximum bandwidth is not necessary. For example, due to the correlation of both
parameters, high sample rates automatically lead to an extended analysis bandwidth.
However, while a high sample rate can be necessary (for example due to postprocessing in an OFDM system), the wide bandwidth is not necessarily required.
RF-Input:
BW = 0.80
* f
out
60
without bandwidth extensions
80
100
120
140
160 180 200
Option B80 / U80
or deactivated
option B160 / U160
Option B40 / U40
Without BW
extension options
... 10000
Output sample
rate f
out
[MHz]
On the other hand, low sample rates lead to small usable I/Q bandwidths. To ensure
the availability of the required bandwidth, the minimum required bandwidth for the
specified sample rate can be selected (via remote command only).
Thus, if one of the bandwidth extension options is installed, the maximum bandwidth
can be restricted manually to a value that can improve the measurement (see "Maxi-
27User Manual 1175.6449.02 ─ 39
R&S®FSW I/Q Analyzer and I/Q Input
mum Bandwidth" on page 196). In this case, the hardware of the "regular" RF path is
used, rather than the hardware required by the bandwidth extension options.
The following improvements can be achieved:
●
Longer measurement time for sample rates under 300 MHz
●
Data processing becomes up to 10 times faster.
●
Digital baseband output becomes available (with bandwidth extension options that
do not support output).
General notes and restrictions
●
The memory extension option R&S FSW-B106 is only available together with the
R&S FSW-B160 or B320 bandwidth extension options.
●
The memory extension option R&S FSW-B108 is only available together with the
R&S FSW-B1200/-B2001/-B800R options.
●
The memory extension option R&S FSW-B124 is only available together with the
R&S FSW-B4001/B6001/B8001 options.
●
In MSRA operating mode, the MSRA primary is restricted to a sample rate of
600 MHz.
●
If digital baseband output is active, the sample rate is restricted to 200 MHz (max.
80 MHz usable I/Q bandwidth).
See "Digital Baseband Output" on page 170
Basics on I/Q data acquisition and processing
Processing analog I/Q data from RF input
5.1.1.3 R&S FSW without additional bandwidth extension options
Sample rate: 100 Hz - 20 GHz
Maximum I/Q bandwidth: 28 MHz
Table 5-3: Maximum I/Q bandwidth
Sample rate Maximum I/Q bandwidth
100 Hz to 28 MHz Proportional up to maximum 28 MHz
28 MHz to 20 GHz 28 MHz
MSRA operating mode
In MSRA operating mode, the MSRA primary is restricted to a sample rate of 600 MHz.
5.1.1.4 R&S FSW with I/Q bandwidth extension option B40 or U40
Sample rate: 100 Hz - 20 GHz
Maximum bandwidth: 40 MHz
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R&S®FSW I/Q Analyzer and I/Q Input
Table 5-4: Maximum I/Q bandwidth
Sample rate Maximum I/Q bandwidth
100 Hz to 50 MHz Proportional up to maximum 40 MHz
50 MHz to 20 GHz 40 MHz
MSRA operating mode
In MSRA operating mode, the MSRA primary is restricted to a sample rate of 600 MHz.
5.1.1.5 R&S FSW with I/Q bandwidth extension option B80 or U80
Sample rate: 100 Hz - 20 GHz
Maximum bandwidth: 80 MHz
Table 5-5: Maximum I/Q bandwidth
Sample rate Maximum I/Q bandwidth
Basics on I/Q data acquisition and processing
Processing analog I/Q data from RF input
100 Hz to 100 MHz Proportional up to maximum 80 MHz
100 MHz to 20 GHz 80 MHz
MSRA operating mode
In MSRA operating mode, the MSRA primary is restricted to a sample rate of 600 MHz.
5.1.1.6 R&S FSW with activated I/Q bandwidth extension option B160 or U160
Sample rate: 100 Hz - 20 GHz
Maximum bandwidth: 160 MHz
Table 5-6: Maximum I/Q bandwidth
Sample rate Maximum I/Q bandwidth
100 Hz to 200 MHz Proportional up to maximum 160 MHz
200 MHz to 20 GHz 160 MHz
Table 5-7: Maximum record length with activated I/Q bandwidth extension option B160 or U160
Sample rate Maximum record length
100 Hz to 200 MHz 440 Msamples
With R&S FSW-B106 option: 1400 Msamples
200 MHz to 20 GHz 220 Msamples
With R&S FSW-B106 option: 700 Msamples
With R&S FSW-B106 option: 700 Msamples
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R&S®FSW I/Q Analyzer and I/Q Input
Notes and restrictions for R&S FSW-B160 or U160
●
In MSRA operating mode, the MSRA primary is restricted to a sample rate of
600 MHz.
●
Digital baseband output is not available for an active R&S FSW-B160 or U160
bandwidth extension. See "Digital Baseband Output" on page 170.
5.1.1.7 R&S FSW with activated I/Q bandwidth extension option B320/U320
Table 5-8: Maximum I/Q bandwidth
Sample rate Maximum I/Q bandwidth
100 Hz to 400 MHz Proportional up to maximum 320 MHz
400 MHz to 20 GHz 320 MHz
Basics on I/Q data acquisition and processing
Processing analog I/Q data from RF input
Figure 5-6: Relationship between maximum usable I/Q bandwidth and output sample rate for active
R&S FSW-B320
30User Manual 1175.6449.02 ─ 39
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