Rohde & Schwarz FSW Series User manual

R&S®FSW-K7
Analog Demodulation Measurement
Option
User Manual
User Manual
(;×êX2)
1173.9240.02 ─ 17
Test & Measurement

This manual applies to the following R&S®FSW models with firmware version 2.00 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)
The following firmware options are described:
●R&S FSW-K7 (1313.1339.02)
The firmware of the instrument makes use of several valuable open source software packages. For information, see the "Open
Source Acknowledgement" on the user documentation CD-ROM (included in delivery).
Rohde & Schwarz would like to thank the open source community for their valuable contribution to embedded computing.
© 2014 Rohde & Schwarz GmbH & Co. KG
Mühldorfstr. 15, 81671 München, Germany
Phone: [phone] - 0
Fax: [phone]
E-mail: [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.

Contents
R&S®FSW-K7
3User Manual 1173.9240.02 ─ 17
Contents
1Preface.................................................................................................... 7
1.1 About this Manual......................................................................................................... 7
1.2 Documentation Overview............................................................................................. 8
1.3 Conventions Used in the Documentation...................................................................9
2Welcome to the Analog Demodulation Application..........................11
2.1 Starting the Analog Demodulation Application........................................................11
2.2 Understanding the Display Information....................................................................12
3Measurements and Result Displays...................................................15
4Measurement Basics........................................................................... 26
4.1 Demodulation Process - Circuit Description............................................................26
4.2 Demodulation Bandwidth...........................................................................................28
4.3 Sample Rate, Measurement Time and Trigger Offset..............................................29
4.4 AF Triggers.................................................................................................................. 31
4.5 AF Filters......................................................................................................................32
4.6 Time Domain Zoom.....................................................................................................32
4.7 Receiving Data Input and Providing Data Output.................................................... 34
4.8 Analog Demodulation in MSRA/MSRT Operating Mode..........................................48
5Configuration........................................................................................50
5.1 Default Settings for Analog Demodulation...............................................................50
5.2 Configuration According to Digital Standards.........................................................51
5.3 Configuration Overview..............................................................................................53
5.4 Input and Frontend Settings...................................................................................... 55
5.5 Trigger Configuration................................................................................................. 94
5.6 Data Acquisition........................................................................................................101
5.7 Demodulation Display.............................................................................................. 106
5.8 Demodulation............................................................................................................ 106
5.9 Output Settings......................................................................................................... 121
5.10 Automatic Settings................................................................................................... 126
6Analysis.............................................................................................. 129
6.1 Trace Settings........................................................................................................... 129

Contents
R&S®FSW-K7
4User Manual 1173.9240.02 ─ 17
6.2 Trace / Data Export Configuration...........................................................................133
6.3 Marker Settings......................................................................................................... 134
6.4 Marker Search Settings and Positioning Functions.............................................. 139
6.5 Marker Function Configuration................................................................................142
6.6 Marker Peak List Configuration............................................................................... 145
6.7 Limit Line Settings and Functions.......................................................................... 147
6.8 Zoom Functions........................................................................................................ 153
6.9 Analysis in MSRA/MSRT Mode................................................................................ 154
7I/Q Data Import and Export................................................................156
7.1 Import/Export Functions.......................................................................................... 156
7.2 How to Export and Import I/Q Data..........................................................................158
8How to Perform Measurements in the Analog Demodulation Appli-
cation...................................................................................................161
9Measurement Example: Demodulating an FM Signal.....................163
10 Optimizing and Troubleshooting the Measurement....................... 169
11 Remote Commands for Analog Demodulation Measurements..... 170
11.1 Introduction............................................................................................................... 171
11.2 Common Suffixes......................................................................................................175
11.3 Activating Analog Demodulation Measurements.................................................. 176
11.4 Configuring the Measurement................................................................................. 180
11.5 Capturing Data and Performing Sweeps................................................................ 277
11.6 Configuring the Result Display................................................................................282
11.7 Retrieving Results.....................................................................................................289
11.8 Analyzing Results..................................................................................................... 299
11.9 Importing and Exporting I/Q Data and Results...................................................... 340
11.10 Commands for Compatibility................................................................................... 341
11.11 Programming Example............................................................................................. 342
AReference............................................................................................345
A.1 Predefined Standards and Settings........................................................................ 345
A.2 I/Q Data File Format (iq-tar)......................................................................................347
List of Remote Commands (AnalogDemod)....................................353

Contents
R&S®FSW-K7
5User Manual 1173.9240.02 ─ 17
Index....................................................................................................361

Contents
R&S®FSW-K7
6User Manual 1173.9240.02 ─ 17

Preface
R&S®FSW-K7
7User Manual 1173.9240.02 ─ 17
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 meas-
urements 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
Alphahabetical list of all remote commands described in the manual
●Index
About this Manual

Preface
R&S®FSW-K7
8User Manual 1173.9240.02 ─ 17
1.2 Documentation Overview
The user documentation for the R&S FSW consists of the following parts:
●Printed Getting Started manual
●Online Help system on the instrument
●Documentation CD-ROM with:
– Getting Started
– User Manuals for base unit and firmware applications
– Service Manual
– Release Notes
– Data sheet and product brochures
Online Help
The Online Help is embedded in the instrument's firmware. It offers quick, context-sen-
sitive access to the complete information needed for operation and programming.
Online help is available using the icon on the toolbar of the R&S FSW.
Web Help
The web help provides online access to the complete information on operating the
R&S FSW and all available options, without downloading. The content of the web help
corresponds to the user manuals for the latest product version. The web help is availa-
ble from the R&S FSW product page at http://www.rohde-schwarz.com/product/
FSW.html > Downloads > Web Help.
Getting Started
This manual is delivered with the instrument in printed form and in PDF format on the
CD. It provides the information needed to set up and start working with the instrument.
Basic operations and handling are described. Safety information is also included.
The Getting Started manual in various languages is also available for download from
the Rohde & Schwarz website, on the R&S FSW product page at http://www2.rohde-
schwarz.com/product/FSW.html.
User Manuals
User manuals are provided for the base unit and each additional (firmware) application.
The user manuals are available in PDF format - in printable form - on the Documenta-
tion CD-ROM delivered with the instrument. In the user manuals, all instrument func-
tions are described in detail. Furthermore, they provide a complete description of the
remote control commands with programming examples.
The user manual for the base unit provides basic information on operating the
R&S FSW in general, and the Spectrum application in particular. Furthermore, the soft-
ware functions that enhance the basic functionality for various applications are descri-
bed here. An introduction to remote control is provided, as well as information on main-
tenance, instrument interfaces and troubleshooting.
Documentation Overview

Preface
R&S®FSW-K7
9User Manual 1173.9240.02 ─ 17
In the individual application manuals, the specific instrument functions of the applica-
tion are described in detail. For additional information on default settings and parame-
ters, refer to the data sheets. Basic information on operating the R&S FSW is not inclu-
ded in the application manuals.
All user manuals are also available for download from the Rohde & Schwarz website,
on the R&S FSW product page at http://www2.rohde-schwarz.com/product/FSW.html.
Service Manual
This manual is available in PDF format on the Documentation CD-ROM delivered with
the instrument. It describes how to check compliance with rated specifications, instru-
ment function, repair, troubleshooting and fault elimination. It contains all information
required for repairing the R&S FSW by replacing modules.
Release Notes
The release notes describe the installation of the firmware, new and modified func-
tions, eliminated problems, and last minute changes to the documentation. The corre-
sponding firmware version is indicated on the title page of the release notes.
The most recent release notes are also available for download from the Rohde &
Schwarz website, on the R&S FSW product page at http://www2.rohde-schwarz.com/
product/FSW.html > Downloads > Firmware.
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.
Conventions Used in the Documentation

Preface
R&S®FSW-K7
10User Manual 1173.9240.02 ─ 17
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
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.
Conventions Used in the Documentation

Welcome to the Analog Demodulation Application
R&S®FSW-K7
11User Manual 1173.9240.02 ─ 17
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
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. Press the MODE key on the front panel of the R&S FSW.
Starting the Analog Demodulation Application

Welcome to the Analog Demodulation Application
R&S®FSW-K7
12User Manual 1173.9240.02 ─ 17
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 5.3, "Configuration Overview",
on page 53).
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 independant 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
R&S®FSW-K7
13User Manual 1173.9240.02 ─ 17
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
R&S®FSW-K7
14User Manual 1173.9240.02 ─ 17
Window title bar information
For each diagram, the header provides the following information:
Fig. 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
R&S®FSW-K7
15User Manual 1173.9240.02 ─ 17
3 Measurements and Result Displays
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 32.
AM Time Domain.......................................................................................................... 15
FM Time Domain...........................................................................................................16
PM Time Domain.......................................................................................................... 17
AM Spectrum................................................................................................................ 18
FM Spectrum.................................................................................................................19
PM Spectrum................................................................................................................ 20
RF Time Domain...........................................................................................................21
RF Spectrum.................................................................................................................22
Result Summary............................................................................................................23
Marker Table.................................................................................................................24
Marker Peak List........................................................................................................... 25
AM Time Domain
Displays the modulation depth of the demodulated AM signal (in %) versus time.

Measurements and Result Displays
R&S®FSW-K7
16User Manual 1173.9240.02 ─ 17
Remote command:
LAY:ADD? '1',RIGH,'XTIM:AM:REL'
(See LAYout:ADD[:WINDow]? on page 284)
FM Time Domain
Displays the frequency spectrum of the demodulated FM signal versus time.

Measurements and Result Displays
R&S®FSW-K7
17User Manual 1173.9240.02 ─ 17
Remote command:
LAY:ADD? '1',RIGH,'XTIM:FM'
(See LAYout:ADD[:WINDow]? on page 284)
PM Time Domain
Displays the phase deviations of the demodulated PM signal (in rad or °) versus time.

Measurements and Result Displays
R&S®FSW-K7
18User Manual 1173.9240.02 ─ 17
Remote command:
LAY:ADD? '1',RIGH,'XTIM:PM'
(See LAYout:ADD[:WINDow]? on page 284)
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
R&S®FSW-K7
19User Manual 1173.9240.02 ─ 17
Remote command:
LAY:ADD? '1',RIGH,'XTIMe:AM:REL:AFSPectrum1'
(see LAYout:ADD[:WINDow]? on page 284)
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
R&S®FSW-K7
20User Manual 1173.9240.02 ─ 17
Remote command:
LAY:ADD? '1',RIGH,'XTIMe:FM:AFSPectrum1'
(see LAYout:ADD[:WINDow]? on page 284)
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.