R&S FSW-K7 User manual

R&S®FSW-K7
Analog Demodulation Measurement
Option
User Manual
User Manual
1173.9240.02 ─ 23
(;×êX2)
Test & Measurement

This manual applies to the following R&S®FSW models with firmware version 2.50 and higher:
●R&S®FSW8 (1312.8000K08)
●R&S®FSW13 (1312.8000K13)
●R&S®FSW26 (1312.8000K26)
●R&S®FSW43 (1312.8000K43)
●R&S®FSW50 (1312.8000K50)
●R&S®FSW67 (1312.8000K67)
●R&S®FSW85 (1312.8000K85)
The following firmware options are described:
●R&S FSW-K7 (1313.1339.02)
© 2016 Rohde & Schwarz GmbH & Co. KG
Mühldorfstr. 15, 81671 München, Germany
Phone: [phone] - 0
Fax: [phone]
Email: [email protected]
Internet: www.rohde-schwarz.com
Subject to change – Data without tolerance limits is not binding.
R&S® is a registered trademark of Rohde & Schwarz GmbH & Co. KG.
Trade names are trademarks of the owners.
The following abbreviations are used throughout this manual: R&S®FSW is abbreviated as R&S FSW. Products of the R&S®SMW
family, e.g. R&S®SMW200A, are abbreviated as R&S SMW.

Contents
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Contents
1 Preface.................................................................................................... 5
1.1 About this Manual......................................................................................................... 5
1.2 Documentation Overview............................................................................................. 6
1.3 Conventions Used in the Documentation...................................................................7
2 Welcome to the Analog Demodulation Application............................9
2.1 Starting the Analog Demodulation Application..........................................................9
2.2 Understanding the Display Information....................................................................10
3 Measurements and Result Displays...................................................13
4 Measurement Basics........................................................................... 24
4.1 Demodulation Process............................................................................................... 24
4.2 Demodulation Bandwidth...........................................................................................26
4.3 Sample Rate and Demodulation Bandwidth.............................................................27
4.4 AF Triggers.................................................................................................................. 28
4.5 AF Filters......................................................................................................................29
4.6 Time Domain Zoom.....................................................................................................29
4.7 Receiving Data Input and Providing Data Output.................................................... 30
4.8 Analog Demodulation in MSRA/MSRT Operating Mode..........................................45
5 Configuration........................................................................................48
5.1 Configuration Overview..............................................................................................48
5.2 Configuration According to Digital Standards.........................................................51
5.3 Input and Frontend Settings...................................................................................... 52
5.4 Trigger Configuration................................................................................................. 96
5.5 Data Acquisition........................................................................................................105
5.6 Demodulation Display.............................................................................................. 109
5.7 Demodulation............................................................................................................ 110
5.8 Output Settings......................................................................................................... 126
5.9 Automatic Settings................................................................................................... 129
6 Analysis.............................................................................................. 133
6.1 Trace Settings........................................................................................................... 133
6.2 Trace / Data Export Configuration...........................................................................136

Contents
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6.3 Working with Markers in the R&S FSW Analog Demodulation application.........138
6.4 Limit Line Settings and Functions.......................................................................... 154
6.5 Analysis in MSRA/MSRT Mode................................................................................ 160
7 I/Q Data Import and Export................................................................162
7.1 Import/Export Functions.......................................................................................... 162
7.2 How to Export and Import I/Q Data..........................................................................164
8 How to Perform Measurements in the Analog Demodulation Appli-
cation...................................................................................................167
8.1 How to Export Trace Data and Numerical Results.................................................168
9 Measurement Example: Demodulating an FM Signal.....................170
10 Optimizing and Troubleshooting the Measurement....................... 176
11 Remote Commands for Analog Demodulation Measurements..... 177
11.1 Introduction............................................................................................................... 178
11.2 Common Suffixes......................................................................................................182
11.3 Activating Analog Demodulation Measurements.................................................. 183
11.4 Configuring the Measurement................................................................................. 187
11.5 Capturing Data and Performing Sweeps................................................................ 294
11.6 Configuring the Result Display................................................................................299
11.7 Retrieving Results.....................................................................................................307
11.8 Analyzing Results..................................................................................................... 319
11.9 Importing and Exporting I/Q Data and Results...................................................... 374
11.10 Deprecated Commands............................................................................................ 375
11.11 Programming Example............................................................................................. 376
Annex.................................................................................................. 379
A Reference............................................................................................379
A.1 Predefined Standards and Settings........................................................................ 379
A.2 I/Q Data File Format (iq-tar)......................................................................................381
List of Remote Commands (AnalogDemod)....................................387
Index....................................................................................................397

Preface
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1 Preface
1.1 About this Manual
This Analog Demodulation User Manual provides all the information specific to the
application. All general instrument functions and settings common to all applications
and operating modes are described in the main R&S FSW User Manual.
The main focus in this manual is on the measurement results and the tasks required to
obtain them. The following topics are included:
●Welcome to the Analog Demodulation Application
Introduction to and getting familiar with the application
●Measurements and Result Displays
Details on supported measurements and their result types
●Measurement Basics
Background information on basic terms and principles in the context of the mea-
surement
●Configuration + Analysis
A concise description of all functions and settings available to configure measure-
ments and analyze results with their corresponding remote control command
●I/Q Data Import and Export
Description of general functions to import and export raw I/Q (measurement) data
●How to Perform Measurements in the Analog Demodulation Application
The basic procedure to perform each measurement and step-by-step instructions
for more complex tasks or alternative methods
●Measurement Examples
Detailed measurement examples to guide you through typical measurement sce-
narios and allow you to try out the application immediately
●Optimizing and Troubleshooting the Measurement
Hints and tips on how to handle errors and optimize the measurement configura-
tion
●Remote Commands for Analog Demodulation Measurements
Remote commands required to configure and perform Analog Demodulation mea-
surements in a remote environment, sorted by tasks
(Commands required to set up the environment or to perform common tasks on the
instrument are provided in the main R&S FSW User Manual)
Programming examples demonstrate the use of many commands and can usually
be executed directly for test purposes
●List of remote commands
Alphabetical list of all remote commands described in the manual
●Index
About this Manual

Preface
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6User Manual 1173.9240.02 ─ 23
1.2 Documentation Overview
This section provides an overview of the R&S FSW user documentation. You find it on
the product page at:
www.rohde-schwarz.com/product/FSW > "Downloads" > "Manuals"
Getting started manual
Introduces the R&S FSW and describes how to set up and start working with the prod-
uct. Includes basic operations, typical measurement examples, and general informa-
tion, e.g. safety instructions, etc. A printed version is delivered with the instrument.
Online help
The online help offers quick, context-sensitive access to the complete information for
the base unit and the software options directly on the instrument.
User manual
Separate manuals for the base unit and the software options are provided for down-
load:
●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 com-
mands with programming examples, and information on maintenance, instrument
interfaces and error messages. Includes the contents of the getting started manual.
●Software option manual
Contains the description of the specific functions of an option. Basic information on
operating the R&S FSW is not included.
The online version of the user manual provides the complete contents for immediate
display on the internet.
Service manual
Describes the performance test for checking the rated specifications, module replace-
ment and repair, firmware update, troubleshooting and fault elimination, and contains
mechanical drawings and spare part lists.
The service manual is available for registered users on the global Rohde & Schwarz
information system (GLORIS, https://gloris.rohde-schwarz.com).
Instrument security procedures manual
Deals with security issues when working with the R&S FSW in secure areas.
Basic safety instructions
Contains safety instructions, operating conditions and further important information.
The printed document is delivered with the instrument.
Documentation Overview

Preface
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7User Manual 1173.9240.02 ─ 23
Data sheet and brochure
The data sheet contains the technical specifications of the R&S FSW. It also lists the
options and their order numbers as well as optional accessories.
The brochure provides an overview of the instrument and deals with the specific char-
acteristics.
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.
www.rohde-schwarz.com/product/FSW > "Downloads" > "Firmware"
Application notes, application cards, white papers, etc.
These documents deal with special applications or background information on particu-
lar topics, see www.rohde-schwarz.com/appnotes.
1.3 Conventions Used in the Documentation
1.3.1 Typographical Conventions
The following text markers are used throughout this documentation:
Convention Description
"Graphical user interface ele-
ments"
All names of graphical user interface elements on the screen, such as
dialog boxes, menus, options, buttons, and softkeys are enclosed by
quotation marks.
KEYS Key names are written in capital letters.
File names, commands,
program code
File names, commands, coding samples and screen output are distin-
guished by their font.
Input Input to be entered by the user is displayed in italics.
Links Links that you can click are displayed in blue font.
"References" References to other parts of the documentation are enclosed by quota-
tion marks.
1.3.2 Conventions for Procedure Descriptions
When describing how to operate the instrument, several alternative methods may be
available to perform the same task. In this case, the procedure using the touchscreen
is described. Any elements that can be activated by touching can also be clicked using
Conventions Used in the Documentation

Preface
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8User Manual 1173.9240.02 ─ 23
an additionally connected mouse. The alternative procedure using the keys on the
instrument or the on-screen keyboard is only described if it deviates from the standard
operating procedures.
The term "select" may refer to any of the described methods, i.e. using a finger on the
touchscreen, a mouse pointer in the display, or a key on the instrument or on a key-
board.
1.3.3 Notes on Screenshots
When describing the functions of the product, we use sample screenshots. These
screenshots are meant to illustrate as much as possible of the provided functions and
possible interdependencies between parameters.
The screenshots usually show a fully equipped product, that is: with all options instal-
led. Thus, some functions shown in the screenshots may not be available in your par-
ticular product configuration.
Conventions Used in the Documentation

Welcome to the Analog Demodulation Application
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2 Welcome to the Analog Demodulation
Application
The R&S FSW-K7 AM/FM/PM measurement demodulator option converts the
R&S FSW into an analog modulation analyzer for amplitude-, frequency- or phase-
modulated signals. It measures not only characteristics of the useful modulation, but
also factors such as residual FM or synchronous modulation.
The digital signal processing in the R&S FSW, used in the Spectrum application for
digital IF filters, is also ideally suited for demodulating AM, FM, or PM signals. The
firmware option R&S FSW-K7 provides the necessary measurement functions.
The R&S FSW Analog Demodulation application features:
●AM, FM, and PM demodulation, with various result displays:
– Modulation signal versus time
– Spectrum of the modulation signal (FFT)
– RF signal power versus time
– Spectrum of the RF signal
●Determining maximum, minimum and average or current values in parallel over a
selected number of measurements
●Maximum accuracy and temperature stability due to sampling (digitization) already
at the IF and digital down-conversion to the baseband (I/Q)
●Error-free AM to FM conversion and vice versa, without deviation errors, frequency
response or frequency drift at DC coupling
●Relative demodulation, in relation to a user-defined or measured reference value
This user manual contains a description of the functionality that the application pro-
vides, 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://www2.rohde-schwarz.com/product/FSW.html).
Installation
You can find detailed installation instructions in the R&S FSW Getting Started manual
or in the Release Notes.
2.1 Starting the Analog Demodulation Application
Analog Demodulation is a separate application on the R&S FSW.
To activate the Analog Demodulation application
1. Select the MODE key.
Starting the Analog Demodulation Application

Welcome to the Analog Demodulation Application
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A dialog box opens that contains all operating modes and applications currently
available on your R&S FSW.
2. Select the "Analog Demodulation" item.
The R&S FSW opens a new measurement channel for the Analog Demodulation
application.
The measurement is started immediately with the default settings. It can be configured
in the Analog Demodulation "Overview" dialog box, which is displayed when you select
the "Overview" softkey from any menu (see Chapter 5.1, "Configuration Overview",
on page 48).
Multiple Measurement Channels and Sequencer Function
When you activate an application, a new measurement channel is created which deter-
mines the measurement settings for that application. The same application can be acti-
vated 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 avail-
able 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 consecu-
tively, a Sequencer function is provided.
If activated, the measurements configured in the currently active channels are per-
formed 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 per-
formed. Sequential operation itself is independent of the currently displayed tab.
For details on the Sequencer function see the R&S FSW User Manual.
2.2 Understanding the Display Information
The following figure shows a measurement diagram during an Analog Demodulation
measurement. All different information areas are labeled. They are explained in more
detail in the following sections.
Understanding the Display Information

Welcome to the Analog Demodulation Application
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1 = Channel bar for firmware and measurement settings
2+3 = Window title bar with diagram-specific (trace) information
4 = Diagram area
5 = Diagram footer with diagram-specific information, depending on result display
6 = Instrument status bar with error messages, progress bar and date/time display
MSRA/MSRT operating mode
In MSRA/MSRT operating mode, additional tabs and elements are available. A colored
background of the screen behind the measurement 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 Applica-
tion and MSRT Operating Mode User Manual.
Channel bar information
In the Analog Demodulation application, the R&S FSW shows the following settings:
Table 2-1: Information displayed in the channel bar in the Analog Demodulation application
Ref Level Reference level
m.+el.Att Mechanical and electronic RF attenuation
Offset Reference level offset
AQT Measurement time for data acquisition.
RBW Resolution bandwidth
DBW Demodulation bandwidth
Freq Center frequency for the RF signal
Understanding the Display Information

Welcome to the Analog Demodulation Application
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Window title bar information
For each diagram, the header provides the following information:
Figure 2-1: Window title bar information in the Analog Demodulation application
1 = Window number
2 = Modulation type
3 = Trace color
4 = Trace number
5 = Detector
6 = Trace mode
7 = Reference value (at the defined reference position)
8 = AF coupling (AC/DC), only in AF time domains, if applicable
9 = Results are selected for demodulation output
Diagram footer information
The diagram footer (beneath the diagram) contains the following information, depend-
ing on the evaluation:
RF Spectrum
CF: Center frequency
of input signal
Sweep points Span: measured span
RF Time domain
CF: Center frequency
of input signal
Sweep points Time per division
AF Spectrum
AF CF: center fre-
quency of demodula-
ted signal
Sweep points AF Span: evaluated span
AF Time domain
CF: Center frequency
of input signal
Sweep points Time per division
For most modes, the number of sweep points shown in the display are indicated in the
diagram footer. In zoom mode, the (rounded) number of currently displayed points are
indicated.
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.
Understanding the Display Information

Measurements and Result Displays
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13User Manual 1173.9240.02 ─ 23
3 Measurements and Result Displays
Access: "Overview" > "Display Config"
Or: MEAS > "Display Config"
The data that was measured by the R&S FSW can be evaluated using various different
methods. In the Analog Demodulation application, up to six evaluation methods can be
displayed simultaneously in separate windows. The results can be displayed as abso-
lute deviations or relative to a reference value or level.
The abbreviation "AF" (for Audio Frequency) refers to the demodulated AM, FM or PM
signal.
Basis for evaluation
All evaluations are based on the I/Q data set acquired during the measurement. The
spectrum of the modulated signal to be evaluated is determined by the demodulation
bandwidth. However, it can be restricted to a limited span ("AF Span") if only part of
the signal is of interest. Furthermore, the time base for evaluations in the time domain
can be restricted to analyze a smaller extract in more detail, see Chapter 4.6, "Time
Domain Zoom", on page 29.
AM Time Domain.......................................................................................................... 13
FM Time Domain...........................................................................................................14
PM Time Domain.......................................................................................................... 15
AM Spectrum................................................................................................................ 16
FM Spectrum.................................................................................................................17
PM Spectrum................................................................................................................ 18
RF Time Domain...........................................................................................................19
RF Spectrum.................................................................................................................20
Result Summary............................................................................................................21
Marker Table.................................................................................................................22
Marker Peak List........................................................................................................... 23
AM Time Domain
Displays the modulation depth of the demodulated AM signal (in %) versus time.

Measurements and Result Displays
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Remote command:
LAY:ADD? '1',RIGH,'XTIM:AM:REL'
(See LAYout:ADD[:WINDow]? on page 301)
FM Time Domain
Displays the frequency spectrum of the demodulated FM signal versus time.

Measurements and Result Displays
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Remote command:
LAY:ADD? '1',RIGH,'XTIM:FM'
(See LAYout:ADD[:WINDow]? on page 301)
PM Time Domain
Displays the phase deviations of the demodulated PM signal (in rad or °) versus time.

Measurements and Result Displays
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Remote command:
LAY:ADD? '1',RIGH,'XTIM:PM'
(See LAYout:ADD[:WINDow]? on page 301)
AM Spectrum
Displays the modulation depth of the demodulated AM signal (in % or dB) versus AF
span. The spectrum is calculated from the demodulated AM signal in the time domain
via FFT.

Measurements and Result Displays
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17User Manual 1173.9240.02 ─ 23
Remote command:
LAY:ADD? '1',RIGH,'XTIMe:AM:REL:AFSPectrum1'
(see LAYout:ADD[:WINDow]? on page 301)
FM Spectrum
Displays the frequency deviations of the demodulated FM signal (in Hz or dB) versus
AF span. The spectrum is calculated from the demodulated AM signal in the time
domain via FFT.

Measurements and Result Displays
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18User Manual 1173.9240.02 ─ 23
Remote command:
LAY:ADD? '1',RIGH,'XTIMe:FM:AFSPectrum1'
(see LAYout:ADD[:WINDow]? on page 301)
PM Spectrum
Displays the phase deviations of the demodulated PM signal (in rad, ° or dB) versus
AF span. The spectrum is calculated from the demodulated AM signal in the time
domain via FFT.

Measurements and Result Displays
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Remote command:
LAY:ADD? '1',RIGH,'XTIMe:PM:AFSPectrum1'
(see LAYout:ADD[:WINDow]? on page 301)
RF Time Domain
Displays the RF power of the input signal versus time. The level values represent the
magnitude of the I/Q data set.

Measurements and Result Displays
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20User Manual 1173.9240.02 ─ 23
Remote command:
LAY:ADD? '1',RIGH,'XTIM:AM'
(see LAYout:ADD[:WINDow]? on page 301)
RF Spectrum
Displays the spectrum of the input signal. In contrast to the Spectrum application, the
frequency values are determined using FFT from the recorded I/Q data set.