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R&S®FSW-K7
AM/FM/PM Modulation Analysis
Option
User Manual
(;×êX2)
1173924002
Version 39
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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)
This manual applies to the following R&S®FSW models with firmware version 3.20 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)
© 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.
1173.9240.02 | Version 39 | R&S®FSW-K7
Throughout this manual, products from Rohde & Schwarz are indicated without the ® symbol, e.g. R&S®FSW is indicated as
R&S FSW. Products of the R&S®SMW family, e.g. R&S®SMW200A, are indicated as R&S SMW.
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R&S®FSW-K7
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
Contents
Contents
1 Documentation overview.......................................................................7
2 Welcome to the R&S FSW AM/FM/PM Modulation Analysis applica-
tion...........................................................................................................9
2.1 Starting AM/FM/PM Modulation Analysis....................................................................9
2.2 Understanding the display information.................................................................... 10
3 Measurements and result displays.................................................... 14
4 Measurement basics............................................................................26
4.1 Demodulation process............................................................................................... 26
4.2 Demodulation bandwidth........................................................................................... 28
4.3 Sample rate and demodulation bandwidth...............................................................29
4.4 AF triggers................................................................................................................... 31
4.5 AF filters.......................................................................................................................31
4.6 Time domain zoom......................................................................................................31
4.7 I/Q data import and export......................................................................................... 33
4.8 Analog modulation analysis in MSRA/MSRT operating mode................................33
5 Configuration........................................................................................35
5.1 Configuration overview.............................................................................................. 35
5.2 Configuration according to standards......................................................................37
5.3 Input and frontend settings........................................................................................39
5.3.1 Input source settings..................................................................................................... 39
5.3.2 Settings for input from I/Q data files..............................................................................45
5.3.3 Amplitude settings.........................................................................................................46
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5.3.4 Frequency..................................................................................................................... 51
5.4 Trigger configuration..................................................................................................52
5.4.1 Trigger source settings..................................................................................................53
5.4.2 Trigger input and output settings...................................................................................60
5.5 Data acquisition.......................................................................................................... 62
5.5.1 Bandwidth settings........................................................................................................ 62
5.5.2 Sweep settings..............................................................................................................64
5.6 Demodulation display.................................................................................................67
5.7 Demodulation.............................................................................................................. 68
5.7.1 Basic demodulation measurement parameters (Demod)..............................................68
5.7.2 Demodulation spectrum................................................................................................ 71
5.7.3 AF filter..........................................................................................................................74
5.7.4 Scaling.......................................................................................................................... 78
Contents
5.7.5 Units.............................................................................................................................. 82
5.7.6 Result table settings......................................................................................................83
5.7.7 Settling time.................................................................................................................. 85
5.8 Output settings............................................................................................................87
5.8.1 Output settings.............................................................................................................. 87
5.8.2 Analog demod output settings.......................................................................................88
5.8.3 Digital I/Q 40G output settings...................................................................................... 90
5.9 Adjusting settings automatically...............................................................................92
6 Analysis................................................................................................ 96
6.1 Trace settings..............................................................................................................96
6.2 Spectrogram settings............................................................................................... 100
6.2.1 General spectrogram settings..................................................................................... 100
6.2.2 Color map settings...................................................................................................... 104
6.3 Trace / data export configuration............................................................................ 105
6.4 Working with markers in the R&S FSW AM/FM/PM Modulation Analysis applica-
tion..............................................................................................................................109
6.4.1 Marker settings............................................................................................................109
6.4.2 Marker search settings and positioning functions........................................................114
6.4.3 Marker search settings for spectrograms.................................................................... 117
6.4.4 Marker function configuration......................................................................................120
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6.5 Analysis in MSRA/MSRT mode................................................................................133
8.1 How to export trace data and numerical results.................................................... 136
10 Optimizing and troubleshooting the measurement........................ 143
11 Remote commands for AM/FM/PM Modulation Analysis............... 144
11.1 Introduction............................................................................................................... 145
11.1.1 Conventions used in descriptions............................................................................... 146
11.1.2 Long and short form.................................................................................................... 146
Contents
7 I/Q data import and export................................................................ 134
8 How to perform measurements in the R&S FSW AM/FM/PM Modula-
tion Analysis application...................................................................135
9 Measurement example: demodulating an FM signal...................... 138
11.1.3 Numeric suffixes..........................................................................................................147
11.1.4 Optional keywords.......................................................................................................147
11.1.5 Alternative keywords................................................................................................... 147
11.1.6 SCPI parameters.........................................................................................................148
11.2 Common suffixes......................................................................................................150
11.3 Activating analog modulation analysis...................................................................150
11.4 Configuring the measurement.................................................................................155
11.4.1 Managing standard settings........................................................................................ 155
11.4.2 Configuring the input................................................................................................... 156
11.4.3 Configuring the output.................................................................................................212
11.4.4 Digital I/Q 40G streaming output commands.............................................................. 215
11.4.5 Frequency settings......................................................................................................217
11.4.6 Configuring the vertical axis (amplitude, scaling)........................................................218
11.4.7 Configuring data acquisition........................................................................................228
11.4.8 Triggering.................................................................................................................... 232
11.4.9 Configuring demodulation........................................................................................... 244
11.4.10 Adjusting settings automatically.................................................................................. 263
11.5 Capturing data and performing sweeps................................................................. 267
11.6 Configuring the result display................................................................................. 272
11.6.1 General window commands........................................................................................272
11.6.2 Working with windows in the display...........................................................................273
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11.7 Retrieving results......................................................................................................279
11.7.1 Retrieving trace results............................................................................................... 280
11.7.2 Exporting trace results................................................................................................ 283
11.7.3 Retrieving result summary values............................................................................... 285
11.7.4 Formats for returned values: ASCII format and binary format.................................... 290
11.7.5 Reference: ASCII file export format............................................................................ 290
11.8 Analyzing results...................................................................................................... 292
11.8.1 Configuring spectrograms........................................................................................... 293
11.8.2 Configuring standard traces........................................................................................ 301
11.8.3 Working with markers remotely...................................................................................307
11.8.4 Marker search (spectrograms).................................................................................... 348
11.8.5 Defining limit checks................................................................................................... 357
11.8.6 Configuring an analysis interval and line (MSRA mode only)..................................... 373
Contents
11.8.7 Configuring an analysis interval and line (MSRT mode only)......................................375
11.9 Importing and exporting I/Q data and results........................................................ 376
11.10 Deprecated commands.............................................................................................378
11.11 Programming example............................................................................................. 379
Annex.................................................................................................. 382
A Predefined standards and settings.................................................. 382
List of Commands (Analog Modulation Analysis).......................... 384
Index....................................................................................................397
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R&S®FSW-K7
1.1 Getting started manual
Documentation overview
Service manual
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
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.
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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1.4 Instrument security procedures
1.5 Printed safety instructions
1.6 Data sheets and brochures
Documentation overview
Application notes, application cards, white papers, etc.
https://gloris.rohde-schwarz.com
Deals with security issues when working with the R&S FSW in secure areas. It is available for download on the Internet.
Provides safety information in many languages. The printed document is delivered with
the product.
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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Welcome to the R&S FSW AM/FM/PM Modulation Analysis application
Starting AM/FM/PM Modulation Analysis
2 Welcome to the R&S FSW AM/FM/PM
Modulation Analysis application
The R&S FSW AM/FM/PM Modulation Analysis application option converts the
R&S FSW into an analog modulation analyzer for amplitude-, frequency- or phasemodulated 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 AM/FM/PM Modulation Analysis 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 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.
Installation
You can find detailed installation instructions in the R&S FSW Getting Started manual
or in the Release Notes.
2.1 Starting AM/FM/PM Modulation Analysis
AM/FM/PM Modulation Analysis is a separate application on the R&S FSW.
To activate AM/FM/PM Modulation Analysis
1. Select the [MODE] key.
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Welcome to the R&S FSW AM/FM/PM Modulation Analysis application
Understanding the display information
A dialog box opens that contains all operating modes and applications currently
available on your R&S FSW.
2. Select the "AM FM PM Analog Demod" item.
The R&S FSW opens a new channel for the application for analog modulation
analysis.
The measurement is started immediately with the default settings. It can be configured
in the analog modulation analysis "Overview" dialog box, which is displayed when you
select the "Overview" softkey from any menu (see Chapter 5.1, "Configuration over-
view", on page 35).
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 "Channel"s 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, to perform the configured measurements consecutively, a
Sequencer function is provided.
If activated, the measurements configured in the currently defined "Channel"s are performed one after the other in the order of the tabs. The currently active measurement is
indicated by a
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.
symbol in the tab label.
2.2 Understanding the display information
The following figure shows a measurement diagram during analog modulation analysis. All different information areas are labeled. They are explained in more detail in the
following sections.
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Welcome to the R&S FSW AM/FM/PM Modulation Analysis application
Understanding the display information
1
2
3
4
5
1 = Channel bar for firmware and measurement settings
2 = Diagram area
3 = Window title bar with diagram-specific (trace) information
4 = Instrument status bar with error messages and date/time display
5 = Diagram footer with diagram-specific information, depending on result display
MSRA/MSRT operating mode
In MSRA/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 Analog Modulation Analysis application, the R&S FSW shows the following settings:
Table 2-1: Information displayed in the channel bar in the application for analog modulation analysis
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
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Welcome to the R&S FSW AM/FM/PM Modulation Analysis application
Understanding the display information
Window title bar information
For each diagram, the header provides the following information:
1 2 345 6 7 8 9
Figure 2-1: Window title bar information in the application for analog modulation analysis
1 = Window number
2 = Window 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, depending on the evaluation:
"RF Spectrum"
CF: Center frequency
of input signal
RF Time domain
CF: Center frequency
of input signal
AF Spectrum
AF CF: center frequency of demodulated signal
AF Time domain
CF: Center frequency
of input signal
Sweep points Span: measured span
Sweep points Time per division
Sweep points AF Span: evaluated span
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.
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Welcome to the R&S FSW AM/FM/PM Modulation Analysis application
Understanding the display information
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.
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Measurements and result displays
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 Modulation Analysis application, up to six evaluation methods
can be displayed simultaneously in separate windows. The results can be displayed as
absolute 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 31.
AM Time Domain...........................................................................................................14
FM Time Domain...........................................................................................................15
PM Time Domain...........................................................................................................16
AM Spectrum................................................................................................................ 17
FM Spectrum.................................................................................................................18
PM Spectrum................................................................................................................ 19
RF Time Domain...........................................................................................................20
RF Spectrum.................................................................................................................21
Result Summary............................................................................................................22
Marker Table................................................................................................................. 24
Marker Peak List........................................................................................................... 24
AM Time Domain
Displays the modulation depth of the demodulated AM signal (in %) versus time.
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Measurements and result displays
Optionally, the settling time can be evaluated and displayed, see Chapter 5.7.7, "Set-
tling time", on page 85.
Remote command:
LAY:ADD? '1',RIGH,'XTIM:AM:REL'
(See LAYout:ADD[:WINDow]? on page 273)
FM Time Domain
Displays the frequency spectrum of the demodulated FM signal versus time.
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Measurements and result displays
Optionally, the settling time can be evaluated and displayed, see Chapter 5.7.7, "Set-
tling time", on page 85.
Remote command:
LAY:ADD? '1',RIGH,'XTIM:FM'
(See LAYout:ADD[:WINDow]? on page 273)
PM Time Domain
Displays the phase deviations of the demodulated PM signal (in rad or °) versus time.
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Measurements and result displays
Optionally, the settling time can be evaluated and displayed, see Chapter 5.7.7, "Set-
tling time", on page 85.
Remote command:
LAY:ADD? '1',RIGH,'XTIM:PM'
(See LAYout:ADD[:WINDow]? on page 273)
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.
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Measurements and result displays
Note: If a high pass or low pass AF filter is defined, the filter is indicated by a vertical
red line in the spectrum display.
Remote command:
LAY:ADD? '1',RIGH,'XTIMe:AM:REL:AFSPectrum1'
(see LAYout:ADD[:WINDow]? on page 273)
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.
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Measurements and result displays
Note: If a high pass or low pass AF filter is defined, the filter is indicated by a vertical
red line in the spectrum display.
Remote command:
LAY:ADD? '1',RIGH,'XTIMe:FM:AFSPectrum1'
(see LAYout:ADD[:WINDow]? on page 273)
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.
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Measurements and result displays
Note: If a high pass or low pass AF filter is defined, the filter is indicated by a vertical
red line in the spectrum display.
Remote command:
LAY:ADD? '1',RIGH,'XTIMe:PM:AFSPectrum1'
(see LAYout:ADD[:WINDow]? on page 273)
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.
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Measurements and result displays
Optionally, the settling time can be evaluated and displayed, see Chapter 5.7.7, "Set-
tling time", on page 85.
Remote command:
LAY:ADD? '1',RIGH,'XTIM:AM'
(see LAYout:ADD[:WINDow]? on page 273)
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.
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Measurements and result displays
Remote command:
LAY:ADD? '1',RIGH,'XTIM:SPECTRUM'
(see LAYout:ADD[:WINDow]? on page 273)
Result Summary
The "result summary" displays the results of the demodulation functions for all windows
in a table.
The following general results are provided:
For each demodulation, the following results are provided:
Label Description
"Carr Power" Measured carrier power
"Carr Offset" Carrier offset to nominal center frequency
"Mod. Depth" Modulation depth
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Measurements and result displays
Table 3-1: Result summary description
Label Description
"Settling Time" Time after which signal remains in a specified value range.
Only evaluated and displayed if enabled, see Chapter 5.7.7, "Settling time",
on page 85.
"+Peak" Positive peak (maximum)
"-Peak" Negative peak (minimum)
"+/-Peak/2" Average of positive and negative peaks
"RMS" Root Mean Square value
"Mod Freq" Modulation frequency
"SINAD" Signal-to-noise-and-distortion
(Calculated only if AF Spectrum is displayed)
Measures the ratio of the total power to the power of noise and harmonic distortions.
The noise and harmonic power is calculated inside the AF spectrum span. The DC
offset is removed before the calculation.
"DISTORT" Modulation distortion in %
(Calculated only if "SINAD" is also calculated)
Measures the distortion of the modulation in relation to the total power of the signal
inside the AF spectrum span. Indicates the quality of the modulation.
"THD" Total harmonic distortion
The ratio of the harmonics to the fundamental and harmonics. All harmonics inside
the AF spectrum span are considered up to the tenth harmonic.
(Calculated only if AF Spectrum is displayed)
Note: Relative demodulation results. Optionally, the demodulation results in relation to
user-defined or measured reference values are determined. See Chapter 5.7.6, "Result
table settings", on page 83.
In addition, the following general information for the input signal is provided:
●
"Carrier Power": the power of the carrier without modulation
●
"Carrier Offset": the deviation of the calculated carrier frequency to the ideal carrier
frequency
●
"Modulation Depth" (AM or "RF Time Domain" only): the difference in amplitude the
carrier signal is modulated with
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Measurements and result displays
Remote command:
LAY:ADD? '1',RIGH,RSUM, see LAYout:ADD[:WINDow]? on page 273
Results:
Chapter 11.7.3, "Retrieving result summary values", on page 285
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 113).
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 273
Results:
CALCulate<n>:MARKer<m>:X on page 310
CALCulate<n>:MARKer<m>:Y? on page 310
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.
You can define search and sort criteria to influence the results of the analysis (see
Chapter 6.4.2.1, "Marker search settings", on page 115).
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 273
Results:
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Measurements and result displays
CALCulate<n>:MARKer<m>:X on page 310
CALCulate<n>:MARKer<m>:Y? on page 310
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4.1 Demodulation process
Measurement basics
Demodulation process
4 Measurement basics
Some background knowledge on basic terms and principles used in Analog Modulation
Analysis measurements is provided here for a better understanding of the required
configuration settings.
● Demodulation process............................................................................................ 26
● Demodulation bandwidth.........................................................................................28
● Sample rate and demodulation bandwidth..............................................................29
● AF triggers...............................................................................................................31
● AF filters..................................................................................................................31
● Time domain zoom..................................................................................................31
● I/Q data import and export...................................................................................... 33
● Analog modulation analysis in MSRA/MSRT operating mode................................33
The demodulation process is shown in Figure 4-1. All calculations are performed simultaneously with the same I/Q data set. Magnitude (= amplitude) and phase of the complex I/Q pairs are determined. The frequency result is obtained from the differential
phase.
For details on general I/Q data processing in the R&S FSW, refer to the reference part
of the I/Q Analysis remote control description in the R&S FSW User Manual.
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Measurement basics
Demodulation process
Figure 4-1: Block diagram of software demodulator
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Measurement basics
Demodulation bandwidth
The AM DC, FM DC and PM DC raw data of the demodulators is fed into the "Trace
Arithmetic" block that combines consecutive data sets. Possible trace modes are:
Clear Write, Max Hold, Min Hold and Average. The output data of the "Trace Arithmetic" block can be read via remote control ([SENS:]ADEM:<evaluation>:RES?,
see [SENSe:]ADEMod:AM[:ABSolute][:TDOMain]:RESult? on page 280.
The collected measured values are evaluated by the selected detector. The result is
displayed on the screen and can be read out via remote control.
In addition, important parameters are calculated:
●
A counter determines the modulation frequency for AM, FM, and PM.
●
average power = carrier power (RF power)
●
average frequency = carrier frequency offset (FM)
●
The modulation depth or the frequency or phase deviation; the deviations are
determined from the trace data
AC coupling is possible with FM and PM display.
4.2 Demodulation bandwidth
The demodulation bandwidth determines the span of the signal that is demodulated. It
is not the 3-dB bandwidth of the filter, but the useful bandwidth which is distortion-free
regarding phase and amplitude.
Therefore the following formulas apply:
●
AM: demodulation bandwidth ≥ 2 x modulation frequency
●
FM: demodulation bandwidth ≥ 2 x (frequency deviation + modulation frequency)
●
PM: demodulation bandwidth ≥ 2 x modulation frequency x (1 + phase deviation)
If the center frequency of the analyzer is not set exactly to the signal frequency, the
demodulation bandwidth must be increased by the carrier offset, in addition to the
requirement described above. The bandwidth must also be increased if FM or PM AC
coupling is selected.
In general, select the demodulation bandwidth as narrow as possible to improve the
S/N ratio. The residual FM caused by noise floor and phase noise increases dramatically with the bandwidth, especially with FM.
For help on determining the adequate demodulation bandwidth, see "Determining the
demodulation bandwidth" on page 143.
A practical example is described in Chapter 9, "Measurement example: demodulating
an FM signal", on page 138.
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4.3 Sample rate and demodulation bandwidth
Measurement basics
Sample rate and demodulation bandwidth
The maximum demodulation bandwidths that can be obtained during the measurement, depending on the sample rate, are listed in the tables below for different demodulation filter types. The allowed value range of the measurement time and trigger offset
depends on the selected demodulation bandwidth and demodulation filter. If the AF filter or the AF trigger are not active, the measurement time increases by 20 %.
A maximum of 24 million samples can be captured, assuming sufficient memory is
available; thus the maximum measurement time can be determined according to the
following formula:
Meas.time
The minimum trigger offset is (-Meas.time
Table 4-1: Available demodulation bandwidths and corresponding sample rates
Demodulation BW Sample Rate (Flat Top) Sample Rate (Gaussian Top)
= Sample count
max
/ sample rate
max
max
)
100 Hz 122.0703125 Hz 400 Hz
200 Hz 244.140625 Hz 800 Hz
400 Hz 488.28125 Hz 1.6 kHz
800 Hz 976.5625 Hz 3.2 kHz
1.6 kHz 1.953125 kHz 6.4 kHz
3.2 kHz 3.90625 kHz 12.8 kHz
6.4 kHz 7.8125 kHz 25.6 kHz
12.5 kHz 15.625 kHz 50 kHz
25 kHz 31.25 kHz 100 kHz
50 kHz 62.5 kHz 200 kHz
100 kHz 125 kHz 400 kHz
200 kHz 250 kHz 800 kHz
400 kHz 500 kHz 1.6 MHz
800 kHz 1 MHz 3.2 MHz
1.6 MHz 2 MHz 6.4 MHz
3 MHz 4 MHz 12 MHz
5 MHz 8 MHz 20 MHz
8 MHz 16 MHz 32 MHz
10 MHz 32 MHz 40 MHz
18 MHz 32 MHz 72 MHz
28 MHz 64 MHz 112 MHz
40 MHz 64 MHz 160 MHz
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Measurement basics
Sample rate and demodulation bandwidth
Demodulation BW Sample Rate (Flat Top) Sample Rate (Gaussian Top)
80 MHz 128 MHz 320 MHz
160 MHz 200 MHz 640 MHz
320 MHz 400 MHz 1280 MHz
500 MHz 600 MHz 2000 MHz
1000 MHz 1250 MHz 4000 MHz
2000 MHz 2500 MHz 8000 MHz
3000 MHz 3750 MHz 12 GHz
4000 MHz 5000 MHz 16 GHz
5000 MHz 6250 MHz 20 GHz
Flat top filters require an I/Q bandwidth at least the size of the demodulation bandwidth
on the R&S FSW. Gauss filters require at least twice the size of the demodulation
bandwidth on the R&S FSW. If necessary, install optional bandwidth extensions on the
R&S FSW to use the required demodulation filter.
Example:
For example, a 500 MHz flat top filter requires a bandwidth extension of 500 MHz or
larger (e.g. B512). A 500 MHz Gauss filter requires a bandwidth extension of
1000 MHz or larger (e.g. B1200).
Large numbers of samples
Principally, the R&S FSW can handle up to 24 million samples. However, when 480001
samples are exceeded, all traces that are not currently being displayed in a window are
deactivated to improve performance. The traces can only be activated again when the
samples are reduced.
Effects of measurement time on the stability of measurement results
Despite amplitude and frequency modulation, the display of carrier power and carrier
frequency offset is stable.
Stability is achieved by a digital filter which sufficiently suppresses the modulation. As
a prerequisite, the measurement time must be ≥ 3 x 1 / modulation frequency, i.e. at
least three periods of the AF signal are recorded.
The mean carrier power for calculating the AM is also calculated with a digital filter.
The filter returns stable results after a measurement time of ≥ 3 x 1 / modulation frequency, i.e. at least three cycles of the AF signal must be recorded before a stable AM
can be shown.
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4.4 AF triggers
4.5 AF filters
Measurement basics
Time domain zoom
The Analog Modulation Analysis application allows triggering to the demodulated signal. The display is stable if a minimum of five modulation periods are within the recording time.
Triggering is always DC-coupled. Therefore triggering is possible directly to the point
where a specific carrier level, phase or frequency is exceeded or not attained.
Additional filters applied after demodulation help filter out unwanted signals, or correct
pre-emphasized input signals. A CCITT filter allows you to evaluate the signal by simulating the characteristics of human hearing.
4.6 Time domain zoom
For evaluations in the time domain, the demodulated data for a particular time span
can be extracted and displayed in more detail using the "Time Domain Zoom" function.
Zooming is useful if the measurement time is very large and thus each sweep point
represents a large time span. The time domain zoom function distributes the available
sweep points only among the time span defined by the zoom area length. The time
span displayed per division of the diagram is decreased. Thus, the display of the
extracted time span becomes more precise.
Figure 4-2: FM time domain measurement with a very long measurement time (200 ms)
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Measurement basics
Time domain zoom
Figure 4-3: FM time domain measurement with time domain zoom (2.0 ms per division)
The time domain zoom area affects not only the diagram display, but the entire evaluation for the current window.
In contrast to the time domain zoom, the graphical zoom is available for all diagram
evaluations. However, the graphical zoom is useful only if more measured values than
trace points are available. The (time) span represented by each measurement point
remains the same.
Time domain zoom Graphical zoom
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4.7 I/Q data import and export
Measurement basics
Analog modulation analysis in MSRA/MSRT operating mode
Baseband signals mostly occur as so-called complex baseband signals, i.e. a signal
representation that consists of two channels; the inphase (I) and the quadrature (Q)
channel. Such signals are referred to as I/Q signals. The complete modulation information and even distortion that originates from the RF, IF or baseband domains can be
analyzed in the I/Q baseband.
Importing and exporting I/Q signals is useful for various applications:
●
Generating and saving I/Q signals in an RF or baseband signal generator or in
external software tools to analyze them with the R&S FSW later.
●
Capturing and saving I/Q signals with the R&S FSW to analyze them with the
R&S FSW or an external software tool later
As opposed to storing trace data, which can be averaged or restricted to peak values, I/Q data is stored as it was captured, without further processing. Multi-channel
data is not supported.
The data is stored as complex values in 32-bit floating-point format. The I/Q data is
stored in a format with the file extension .iq.tar.
For a detailed description, see the R&S FSW I/Q Analyzer and I/Q Input User Manual.
For example, you can capture I/Q data using the I/Q Analyzer application, if available,
and then analyze that data later using the R&S FSW AM/FM/PM Modulation Analysis
application.
An application note on converting Rohde & Schwarz I/Q data files is available from the
Rohde & Schwarz website:
1EF85: Converting R&S I/Q data files
Export only in MSRA mode
In MSRA mode, I/Q data can only be exported to other applications; I/Q data cannot be
imported to the MSRA primary or any MSRA secondary applications.
4.8 Analog modulation analysis in MSRA/MSRT operating mode
The R&S FSW AM/FM/PM Modulation Analysis application can also be used to analyze data in MSRA or MSRT operating mode. The main difference between the two
modes is that in MSRA mode, an I/Q analyzer performs data acquisition, while in
MSRT mode, a real-time measurement is performed to capture data.
In MSRA/MSRT operating mode, only the MSRA/MSRT primary actually captures data.
The data acquisition settings for an AM/FM/PM Modulation Analysis application channel in MSRA/MSRT mode configure the analysis interval, not an actual data capture
from the input signal.
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Measurement basics
Analog modulation analysis in MSRA/MSRT operating mode
In addition, a capture offset can be defined, i.e. an offset from the start of the captured
data to the start of the analysis interval for AM/FM/PM Modulation Analysis.
The currently used analysis interval (in seconds, related to measurement start) is indicated in the window header for each result display.
Analysis line
A frequent question when analyzing multi-standard signals is how each data channel is
correlated (in time) to others. Thus, an analysis line has been introduced. The analysis
line is a common time marker for all MSRA secondary applications. It can be positioned in any MSRA secondary application or the MSRA primary and is then adjusted
in all other secondary applications. Thus, you can easily analyze the results at a specific time in the measurement in all secondary applications and determine correlations.
If the analysis interval of the secondary application contains the marked point in time,
the line is indicated in all time-based result displays, such as time, symbol, slot or bit
diagrams. By default, the analysis line is displayed. However, you can hide it from view
manually. In all result displays, the "AL" label in the window title bar indicates whether
the analysis line lies within the analysis interval or not:
●
orange "AL": the line lies within the interval
●
white "AL": the line lies within the interval, but is not displayed (hidden)
●
no "AL": the line lies outside the interval
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 Real-Time Spectrum Application and MSRT Operating Mode User Manual.
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Configuration
Configuration overview
5 Configuration
Access: [MODE] > "AM FM PM Analog Demod"
Analog Modulation Analysis requires a special application on the R&S FSW.
When you activate an R&S FSW AM/FM/PM Modulation Analysis application the first
time, a set of parameters is passed on from the currently active application. After initial
setup, the parameters for the channel are stored upon exiting and restored upon reentering the channel. Thus, you can switch between applications quickly and easily.
When you activate the R&S FSW AM/FM/PM Modulation Analysis application, Analog
Modulation Analysis for the input signal is started automatically with the default configuration. The "AM FM PM Analog Demod" menu is displayed and provides access to
the most important configuration functions.
The remote commands required to perform these tasks are described in Chapter 11,
"Remote commands for AM/FM/PM Modulation Analysis", on page 144.
Predefined settings
For commonly performed measurements, standard setup files are provided for quick
and easy configuration. Simply load an existing standard settings file and, if necessary,
adapt the measurement settings to your specific requirements.
For an overview of predefined standards and settings see Chapter A, "Predefined
standards and settings", on page 382.
● Configuration overview............................................................................................35
● Configuration according to standards..................................................................... 37
● Input and frontend settings......................................................................................39
● Trigger configuration............................................................................................... 52
● Data acquisition.......................................................................................................62
● Demodulation display..............................................................................................67
● Demodulation..........................................................................................................68
● Output settings........................................................................................................87
● Adjusting settings automatically..............................................................................92
5.1 Configuration overview
Access: "Meas Config" > "Overview"
Using the R&S FSW AM/FM/PM Modulation Analysis application you can perform Analog Modulation Analysis using predefined standard setting files, or independently of
standards using user-defined measurement settings. Such settings can be stored for
recurrent use.
Thus, configuring AM/FM/PM Modulation Analysis measurements requires one of the
following tasks:
●
Selecting an existing standard settings file and, if necessary, adapting the measurement settings to your specific requirements.
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Configuration
Configuration overview
●
Configuring the measurement settings and, if necessary, storing the settings in a
file.
"Overview" window
Throughout the channel configuration, an overview of the most important currently
defined settings is provided in the "Overview".
In addition to the main measurement settings, the "Overview" provides quick access to
the main settings dialog boxes. The individual configuration steps are displayed in the
order of the data flow. In particular, the "Overview" provides quick access to the following configuration dialog boxes (listed in the recommended order of processing):
1. Input/Frontend
See Chapter 5.3, "Input and frontend settings", on page 39
2. Trigger
See Chapter 5.4, "Trigger configuration", on page 52
3. Data Acquisition
See Chapter 5.5, "Data acquisition", on page 62
4. Demod/Display
See Chapter 5.6, "Demodulation display", on page 67
5. Demodulation Settings
See Chapter 5.7, "Demodulation", on page 68
6. Analysis
See Chapter 6, "Analysis", on page 96
7. (Optionally:) Outputs
See Chapter 5.8.1, "Output settings", on page 87
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Configuration
Configuration according to standards
To configure settings
► Select any button in the "Overview" to open the corresponding dialog box.
Select a setting in the channel bar (at the top of the channel tab) to change a specific setting.
Preset Channel
Select the "Preset Channel" button in the lower left-hand corner of the "Overview" to
restore all measurement settings in the current channel to their default values.
Note: Do not confuse the "Preset Channel" button with the [Preset] key, which restores
the entire instrument to its default values and thus closes all channels on the
R&S FSW (except for the default channel)!
Remote command:
SYSTem:PRESet:CHANnel[:EXEC] on page 154
Setup Standard
Opens a file selection dialog box to select a predefined setup file. See "Setup Stan-
dard" on page 38.
Specific Settings for
The channel can contain several windows for different results. Thus, the settings indicated in the "Overview" and configured in the dialog boxes vary depending on the
selected window.
Select an active window from the "Specific Settings for" selection list that is displayed
in the "Overview" and in all window-specific configuration dialog boxes.
The "Overview" and dialog boxes are updated to indicate the settings for the selected
window.
5.2 Configuration according to standards
Access: "Overview" > "Setup Standard"
Various predefined settings files for common standards are provided for use with the
R&S FSW AM/FM/PM Modulation Analysis application. In addition, you can create
your own settings files for user-specific measurements.
For details on which settings are defined and an overview of predefined standards see
Chapter A, "Predefined standards and settings", on page 382.
Setup Standard............................................................................................................. 38
└ Selecting Storage Location - Drive/ Path/ Files.............................................. 38
└ File Name........................................................................................................38
└ Load Standard................................................................................................ 38
└ Save Standard................................................................................................ 38
└ Delete Standard..............................................................................................38
└ Restore Standard Files................................................................................... 38
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Configuration
Configuration according to standards
Setup Standard
Opens a file selection dialog box to select a predefined setup file. The predefined settings are configured in the R&S FSW AM/FM/PM Modulation Analysis application,
which allows for quick and easy configuration for commonly performed measurements.
Selecting Storage Location - Drive/ Path/ Files ← Setup Standard
Select the storage location of the file on the instrument or an external drive.
The default storage location for the settings files is:
C:\R_S\INSTR\USER\predefined\AdemodPredefined.
Note: Saving instrument settings in secure user mode.
In secure user mode, settings that are stored on the instrument are stored to volatile
memory, which is restricted to 256 MB. Thus, a "memory limit reached" error can occur
although the hard disk indicates that storage space is still available.
To store data permanently, select an external storage location such as a USB memory
device.
For details, see "Protecting Data Using the Secure User Mode" in the "Data Management" section of the R&S FSW base unit user manual.
File Name ← Setup Standard
Contains the name of the data file without the path or extension.
File names must be compatible with the Windows conventions for file names. In partic-
ular, they must not contain special characters such as ":", "*", "?".
For details on the filename and location, see the "Data Management" topic in the
R&S FSW User Manual.
Load Standard ← Setup Standard
Loads the selected measurement settings file.
Remote command:
[SENSe:]ADEMod:PRESet[:STANdard] on page 155
Save Standard ← Setup Standard
Saves the current measurement settings for a specific standard as a file with the
defined name.
Remote command:
[SENSe:]ADEMod:PRESet:STORe on page 156
Delete Standard ← Setup Standard
Deletes the selected standard. Standards predefined by Rohde & Schwarz can also be
deleted. A confirmation query is displayed to avoid unintentional deletion of the standard.
Note: Restoring predefined standard files. The standards predefined by Rohde &
Schwarz available at the time of delivery can be restored using the "Restore Standard
Files" function (see "Restore Standard Files" on page 38).
Restore Standard Files ← Setup Standard
Restores the standards predefined by Rohde & Schwarz available at the time of delivery.
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5.3 Input and frontend settings
Configuration
Input and frontend settings
Note that this function overwrites customized standards that have the same name as
predefined standards.
Remote command:
[SENSe:]ADEMod:PRESet:RESTore on page 156
Access: "Overview" > "Input/Frontend"
The source and characteristics of the input signal to be demodulated are configured in
the "Input/Frontend Settings" dialog box.
Amplitude settings for analog baseband input
Amplitude settings for analog baseband input are described in the R&S FSW I/Q Analyzer and I/Q Input User Manual
● Input source settings...............................................................................................39
● Settings for input from I/Q data files........................................................................45
● Amplitude settings...................................................................................................46
● Frequency............................................................................................................... 51
5.3.1 Input source settings
Access: "Overview" > "Input/Frontend" > "Input Source"
The input source determines which data the R&S FSW analyzes.
The default input source for the R&S FSW is "Radio Frequency", i.e. the signal at the
"RF Input" connector of the R&S FSW. If no additional options are installed, this is the
only available input source.
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Configuration
Input and frontend settings
Further input sources
The R&S FSW AM/FM/PM Modulation Analysis application application can also process input from the following optional sources:
●
I/Q Input files
●
External mixer
●
"Digital Baseband" interface (R&S FSW-B17)
●
"Analog Baseband" interface (R&S FSW-B71)
●
Baseband oscilloscope input (R&S FSW-B2071)
●
2 GHz / 5 GHz bandwidth extension (R&S FSW-B2000/B5000)
●
Probes
●
External generator
●
Power sensors
For details, see the R&S FSW I/Q Analyzer and I/Q Input User Manual.
Since the Digital I/Q input and the Analog Baseband input use the same digital signal
path, both cannot be used simultaneously. When one is activated, established connections for the other are disconnected. When the second input is deactivated, connections to the first are re-established. Reconnecting can cause a short delay in data
transfer after switching the input source.
External mixers are not supported in MSRA / MSRT mode.
● Radio frequency input............................................................................................. 40
● Settings for input from I/Q data files........................................................................43
5.3.1.1 Radio frequency input
Access: "Overview" > "Input/Frontend" > "Input Source" > "Radio Frequency"
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Configuration
Input and frontend settings
RF Input Protection
The RF input connector of the R&S FSW must be protected against signal levels that
exceed the ranges specified in the data sheet. Therefore, the R&S FSW is equipped
with an overload protection mechanism for DC and signal frequencies up to 30 MHz.
This mechanism becomes active as soon as the power at the input mixer exceeds the
specified limit. It ensures that the connection between RF input and input mixer is cut
off.
When the overload protection is activated, an error message is displayed in the status
bar ("INPUT OVLD"), and a message box informs you that the RF input was disconnected. Furthermore, a status bit (bit 3) in the STAT:QUES:POW status register is set.
In this case, you must decrease the level at the RF input connector and then close the
message box. Then measurement is possible again. Reactivating the RF input is also
possible via the remote command INPut<ip>:ATTenuation:PROTection:RESet.
Radio Frequency State................................................................................................. 41
Input Coupling...............................................................................................................41
Impedance.................................................................................................................... 42
Direct Path.................................................................................................................... 42
High Pass Filter 1 to 3 GHz...........................................................................................42
YIG-Preselector.............................................................................................................43
Input Connector.............................................................................................................43
Radio Frequency State
Activates input from the "RF Input" connector.
For R&S FSW85 models with two input connectors, you must define which input
source is used for each measurement channel.
If an external frontend is active, select the connector the external frontend is connected
to. You cannot use the other RF input connector simultaneously for the same channel.
However, you can configure the use of the other RF input connector for another active
channel at the same time.
"Input 1"
"Input 2"
Remote command:
INPut<ip>:SELect on page 160
INPut<ip>:TYPE on page 161
Input Coupling
The RF input of the R&S FSW can be coupled by alternating current (AC) or direct current (DC).
This function is not available for input from the optional "Digital Baseband" interface or
from the optional "Analog Baseband" interface.
1.00 mm RF input connector for frequencies up to 85 GHz (90 GHz
with option R&S FSW-B90G)
1.85 mm RF input connector for frequencies up to 67 GHz
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Configuration
Input and frontend settings
AC coupling blocks any DC voltage from the input signal. AC coupling is activated by
default to prevent damage to the instrument. Very low frequencies in the input signal
can be distorted.
However, some specifications require DC coupling. In this case, you must protect the
instrument from damaging DC input voltages manually. For details, refer to the data
sheet.
Remote command:
INPut<ip>:COUPling on page 158
Impedance
For some measurements, the reference impedance for the measured levels of the
R&S FSW can be set to 50 Ω or 75 Ω.
Select 75 Ω if the 50 Ω input impedance is transformed to a higher impedance using a
75 Ω adapter of the RAZ type. (That corresponds to 25Ω in series to the input impedance of the instrument.) The correction value in this case is 1.76 dB = 10 log (75Ω/
50Ω).
This value also affects the unit conversion (see "Reference Level" on page 47).
This function is not available for input from the optional "Digital Baseband" interface or
from the optional "Analog Baseband" interface. For analog baseband input, an impedance of 50 Ω is always used.
Remote command:
INPut<ip>:IMPedance on page 159
Direct Path
Enables or disables the use of the direct path for small frequencies.
In spectrum analyzers, passive analog mixers are used for the first conversion of the
input signal. In such mixers, the LO signal is coupled into the IF path due to its limited
isolation. The coupled LO signal becomes visible at the RF frequency 0 Hz. This effect
is referred to as LO feedthrough.
To avoid the LO feedthrough the spectrum analyzer provides an alternative signal path
to the A/D converter, referred to as the direct path. By default, the direct path is
selected automatically for RF frequencies close to zero. However, this behavior can be
disabled. If "Direct Path" is set to "Off", the spectrum analyzer always uses the analog
mixer path.
"Auto"
"Off"
Remote command:
INPut<ip>:DPATh on page 158
High Pass Filter 1 to 3 GHz
Activates an additional internal highpass filter for RF input signals from 1 GHz to
3 GHz. This filter is used to remove the harmonics of the analyzer to measure the harmonics for a DUT, for example.
This function requires an additional hardware option.
(Default) The direct path is used automatically for frequencies close
to zero.
The analog mixer path is always used.
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Configuration
Input and frontend settings
Note: For RF input signals outside the specified range, the high-pass filter has no
effect. For signals with a frequency of approximately 4 GHz upwards, the harmonics
are suppressed sufficiently by the YIG-preselector, if available.)
Remote command:
INPut<ip>:FILTer:HPASs[:STATe] on page 158
YIG-Preselector
Enables or disables the YIG-preselector, if available on the R&S FSW.
An internal YIG-preselector at the input of the R&S FSW ensures that image frequen-
cies are rejected. However, image rejection is only possible for a restricted bandwidth.
To use the maximum bandwidth for signal analysis you can disable the YIG-preselector
at the input of the R&S FSW, which can lead to image-frequency display.
Note: Note that the YIG-preselector is active only on frequencies greater than 8 GHz.
Therefore, switching the YIG-preselector on or off has no effect if the frequency is
below that value.
To use the optional 90 GHz frequency extension (R&S FSW-B90G), the YIG-preselector must be disabled.
Remote command:
INPut<ip>:FILTer:YIG[:STATe] on page 159
Input Connector
Determines which connector the input data for the measurement is taken from.
For more information on the "Analog Baseband" interface (R&S FSW-B71), see the
R&S FSW I/Q Analyzer and I/Q Input user manual.
"RF"
"RF Probe"
"Baseband
Input I"
Remote command:
INPut<ip>:CONNector on page 157
5.3.1.2 Settings for input from I/Q data files
Access: "Overview" > "Input/Frontend" > "Input Source" > "I/Q File"
(Default:) The "RF Input" connector
The "RF Input" connector with an adapter for a modular probe
This setting is only available if a probe is connected to the "RF Input"
connector.
The optional "Baseband Input I" connector
This setting is only available if the optional "Analog Baseband" interface is installed and active for input. It is not available for the
R&S FSW67.
For R&S FSW85 models with two input connectors, this setting is
only available for "Input 1".
Or: [INPUT/OUTPUT] > "Input Source Config" > "Input Source" > "I/Q File"
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Configuration
Input and frontend settings
I/Q Input File State........................................................................................................ 44
Select I/Q data file.........................................................................................................44
File Repetitions............................................................................................................. 45
I/Q Input File State
Enables input from the selected I/Q input file.
If enabled, the application performs measurements on the data from this file. Thus,
most measurement settings related to data acquisition (attenuation, center frequency,
measurement bandwidth, sample rate) cannot be changed. The measurement time
can only be decreased to perform measurements on an extract of the available data
only.
Note: Even when the file input is disabled, the input file remains selected and can be
enabled again quickly by changing the state.
Remote command:
INPut<ip>:SELect on page 160
Select I/Q data file
Opens a file selection dialog box to select an input file that contains I/Q data.
The I/Q data file must be in one of the following supported formats:
.iq.tar
●
.iqw
●
.csv
●
.mat
●
.wv
●
.aid
●
For details on formats, see the R&S FSW I/Q Analyzer and I/Q Input user manual.
Note: Only a single data stream or channel can be used as input, even if multiple
streams or channels are stored in the file.
Note: For some file formats that do not provide the sample rate and measurement time
or record length, you must define these parameters manually. Otherwise the traces are
not visible in the result displays.
The default storage location for I/Q data files is C:\R_S\INSTR\USER.
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R&S®FSW-K7
5.3.2 Settings for input from I/Q data files
Configuration
Input and frontend settings
Remote command:
INPut<ip>:FILE:PATH on page 162
File Repetitions
Determines how often the data stream is repeatedly copied in the I/Q data memory to
create a longer record. If the available memory is not sufficient for the specified number of repetitions, the largest possible number of complete data streams is used.
Remote command:
TRACe:IQ:FILE:REPetition:COUNt on page 163
Access: "Overview" > "Input/Frontend" > "Input Source" > "I/Q File"
Or: [INPUT/OUTPUT] > "Input Source Config" > "Input Source" > "I/Q File"
I/Q Input File State........................................................................................................ 45
Select I/Q data file.........................................................................................................46
File Repetitions............................................................................................................. 46
I/Q Input File State
Enables input from the selected I/Q input file.
If enabled, the application performs measurements on the data from this file. Thus,
most measurement settings related to data acquisition (attenuation, center frequency,
measurement bandwidth, sample rate) cannot be changed. The measurement time
can only be decreased to perform measurements on an extract of the available data
only.
Note: Even when the file input is disabled, the input file remains selected and can be
enabled again quickly by changing the state.
Remote command:
INPut<ip>:SELect on page 160
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R&S®FSW-K7
Configuration
Input and frontend settings
Select I/Q data file
Opens a file selection dialog box to select an input file that contains I/Q data.
The I/Q data file must be in one of the following supported formats:
.iq.tar
●
.iqw
●
.csv
●
.mat
●
.wv
●
.aid
●
For details on formats, see the R&S FSW I/Q Analyzer and I/Q Input user manual.
Note: Only a single data stream or channel can be used as input, even if multiple
streams or channels are stored in the file.
Note: For some file formats that do not provide the sample rate and measurement time
or record length, you must define these parameters manually. Otherwise the traces are
not visible in the result displays.
The default storage location for I/Q data files is C:\R_S\INSTR\USER.
Remote command:
INPut<ip>:FILE:PATH on page 162
File Repetitions
Determines how often the data stream is repeatedly copied in the I/Q data memory to
create a longer record. If the available memory is not sufficient for the specified number of repetitions, the largest possible number of complete data streams is used.
Remote command:
TRACe:IQ:FILE:REPetition:COUNt on page 163
5.3.3 Amplitude settings
Access: "Overview" > "Input/Frontend" > "Amplitude"
Amplitude settings determine how the R&S FSW must process or display the expected
input power levels.
Amplitude settings for input from the optional "Analog Baseband" interface are described in the R&S FSW I/Q Analyzer and I/Q Input User Manual.
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R&S®FSW-K7
Configuration
Input and frontend settings
Reference Level............................................................................................................47
└ Shifting the Display (Offset)............................................................................ 48
└ Unit..................................................................................................................48
└ Setting the Reference Level Automatically (Auto Level).................................48
RF Attenuation.............................................................................................................. 49
└ Attenuation Mode / Value................................................................................49
Using Electronic Attenuation.........................................................................................49
Input Settings................................................................................................................ 50
└ Preamplifier.....................................................................................................50
└ Ext. PA Correction...........................................................................................50
Reference Level
Defines the expected maximum input signal level. Signal levels above this value are
possibly not measured correctly, which is indicated by the "IF Overload" status display
("OVLD" for analog baseband or digital baseband input).
The reference level can also be used to scale power diagrams; the reference level is
then used for the calculation of the maximum on the y-axis.
Since the hardware of the R&S FSW is adapted according to this value, it is recommended that you set the reference level close above the expected maximum signal
level. Thus you ensure an optimum measurement (no compression, good signal-tonoise ratio).
Note: Note that for input from the External Mixer (R&S FSW-B21) the maximum refer-
ence level also depends on the conversion loss; see the R&S FSW base unit user
manual for details.
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R&S®FSW-K7
Configuration
Input and frontend settings
Remote command:
DISPlay[:WINDow<n>][:SUBWindow<w>]:TRACe<t>:Y[:SCALe]:RLEVel
on page 219
Shifting the Display (Offset) ← Reference Level
Defines an arithmetic level offset. This offset is added to the measured level. In some
result displays, the scaling of the y-axis is changed accordingly.
Define an offset if the signal is attenuated or amplified before it is fed into the
R&S FSW so the application shows correct power results. All displayed power level
results are shifted by this value.
The setting range is ±200 dB in 0.01 dB steps.
Note, however, that the internal reference level (used to adjust the hardware settings to
the expected signal) ignores any "Reference Level Offset". Thus, it is important to keep
in mind the actual power level the R&S FSW must handle. Do not rely on the displayed
reference level (internal reference level = displayed reference level - offset).
Remote command:
DISPlay[:WINDow<n>][:SUBWindow<w>]:TRACe<t>:Y[:SCALe]:RLEVel:
OFFSet on page 220
Unit ← Reference Level
The R&S FSW measures the signal voltage at the RF input.
In the default state, the level is displayed at a power level of 1 mW (= dBm). Via the
known input impedance (50 Ω or 75 Ω, see "Impedance" on page 42), conversion to
other units is possible.
The following units are available and directly convertible:
●
dBm
●
dBmV
●
dBμV
●
dBμA
●
dBpW
●
Volt
●
Ampere
●
Watt
Remote command:
INPut<ip>:IMPedance on page 159
CALCulate<n>:UNIT:POWer on page 219
Setting the Reference Level Automatically (Auto Level) ← Reference Level
Automatically determines a reference level which ensures that no overload occurs at
the R&S FSW for the current input data. At the same time, the internal attenuators and
the preamplifier (for analog baseband input: the full-scale level) are adjusted. As a
result, the signal-to-noise ratio is optimized, while signal compression and clipping are
minimized.
To determine the required reference level, a level measurement is performed on the
R&S FSW.
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R&S®FSW-K7
Configuration
Input and frontend settings
If necessary, you can optimize the reference level further. Decrease the attenuation
level manually to the lowest possible value before an overload occurs, then decrease
the reference level in the same way.
When using the optional 2 GHz / 5 GHz bandwidth extension (B2000/B5000) or the
optional Oscilloscope Baseband Input, the level measurement is performed on the connected oscilloscope. For B2000/B5000, y-axis scaling on the oscilloscope is limited to
a minimum of 5 mV per division.
You can change the measurement time for the level measurement if necessary (see
"Changing the Automatic Measurement Time (Meastime Manual)" on page 94).
Remote command:
[SENSe:]ADJust:LEVel on page 266
RF Attenuation
Defines the attenuation applied to the RF input of the R&S FSW.
Attenuation Mode / Value ← RF Attenuation
The RF attenuation can be set automatically as a function of the selected reference
level (Auto mode). Automatic attenuation ensures that no overload occurs at the RF
Input connector for the current reference level. It is the default setting.
By default and when no (optional) electronic attenuation is available, mechanical
attenuation is applied.
This function is not available for input from the optional "Digital Baseband" interface.
In "Manual" mode, you can set the RF attenuation in 1 dB steps (down to 0 dB). Other
entries are rounded to the next integer value. The range is specified in the data sheet.
If the defined reference level cannot be set for the defined RF attenuation, the reference level is adjusted accordingly and the warning "limit reached" is displayed.
NOTICE! Risk of hardware damage due to high power levels. When decreasing the
attenuation manually, ensure that the power level does not exceed the maximum level
allowed at the RF input, as an overload can lead to hardware damage.
Remote command:
INPut<ip>:ATTenuation on page 220
INPut<ip>:ATTenuation:AUTO on page 221
Using Electronic Attenuation
If the (optional) Electronic Attenuation hardware is installed on the R&S FSW, you can
also activate an electronic attenuator.
In "Auto" mode, the settings are defined automatically; in "Manual" mode, you can
define the mechanical and electronic attenuation separately.
This function is not available for input from the optional "Digital Baseband" interface.
Note: Electronic attenuation is not available for stop frequencies (or center frequencies
in zero span) above 15 GHz.
In "Auto" mode, RF attenuation is provided by the electronic attenuator as much as
possible to reduce the amount of mechanical switching required. Mechanical attenuation can provide a better signal-to-noise ratio, however.
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R&S®FSW-K7
Configuration
Input and frontend settings
When you switch off electronic attenuation, the RF attenuation is automatically set to
the same mode (auto/manual) as the electronic attenuation was set to. Thus, the RF
attenuation can be set to automatic mode, and the full attenuation is provided by the
mechanical attenuator, if possible.
The electronic attenuation can be varied in 1 dB steps. If the electronic attenuation is
on, the mechanical attenuation can be varied in 5 dB steps. Other entries are rounded
to the next lower integer value.
For the R&S FSW85, the mechanical attenuation can be varied only in 10 dB steps.
If the defined reference level cannot be set for the given attenuation, the reference
level is adjusted accordingly and the warning "limit reached" is displayed in the status
bar.
Remote command:
INPut<ip>:EATT:STATe on page 223
INPut<ip>:EATT:AUTO on page 222
INPut<ip>:EATT on page 222
Input Settings
Some input settings affect the measured amplitude of the signal, as well.
The parameters "Input Coupling" and "Impedance" are identical to those in the "Input"
settings.
Preamplifier ← Input Settings
If the (optional) internal preamplifier hardware is installed, a preamplifier can be activated for the RF input signal.
You can use a preamplifier to analyze signals from DUTs with low output power.
Note: If an optional external preamplifier is activated, the internal preamplifier is auto-
matically disabled, and vice versa.
This function is not available for input from the (optional) "Digital Baseband" interface.
For all R&S FSW models except for R&S FSW85, the following settings are available:
"Off"
"15 dB"
"30 dB"
For R&S FSW85 models, the input signal is amplified by 30 dB if the preamplifier is
activated.
Remote command:
INPut<ip>:GAIN:STATe on page 224
INPut<ip>:GAIN[:VALue] on page 225
Ext. PA Correction ← Input Settings
This function is only available if an external preamplifier is connected to the R&S FSW,
and only for frequencies above 1 GHz. For details on connection, see the preamplifier's
documentation.
Using an external preamplifier, you can measure signals from devices under test with
low output power, using measurement devices which feature a low sensitivity and do
not have a built-in RF preamplifier.
Deactivates the preamplifier.
The RF input signal is amplified by about 15 dB.
The RF input signal is amplified by about 30 dB.
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R&S®FSW-K7
5.3.4 Frequency
Configuration
Input and frontend settings
When you connect the external preamplifier, the R&S FSW reads out the touchdown
(.S2P) file from the EEPROM of the preamplifier. This file contains the s-parameters of
the preamplifier. As soon as you connect the preamplifier to the R&S FSW, the preamplifier is permanently on and ready to use. However, you must enable data correction
based on the stored data explicitly on the R&S FSW using this setting.
When enabled, the R&S FSW automatically compensates the magnitude and phase
characteristics of the external preamplifier in the measurement results. Any internal
preamplifier, if available, is disabled.
For R&S FSW85 models with two RF inputs, you can enable correction from the external preamplifier for each input individually, but not for both at the same time.
When disabled, no compensation is performed even if an external preamplifier remains
connected.
Remote command:
INPut<ip>:EGAin[:STATe] on page 223
Access: "Overview" > "Input/Frontend" > "Frequency" tab
Center Frequency......................................................................................................... 51
Center Frequency Stepsize...........................................................................................51
Center Frequency
Defines the center frequency of the signal in Hertz.
The allowed range of values for the center frequency depends on the frequency span.
span > 0: span
f
and span
max
/2 ≤ f
min
depend on the instrument and are specified in the data sheet.
min
center
≤ f
max
– span
min
/2
Remote command:
[SENSe:]FREQuency:CENTer on page 217
Center Frequency Stepsize
Defines the step size of the center frequency. The step size can be coupled to the
demodulation bandwidth, or you can set it to a fixed value manually.
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R&S®FSW-K7
Configuration
Trigger configuration
"0.1 * Demod
BW"
"0.5 * Demod
BW"
"X * Demod
BW"
"= Center"
"Manual"
Remote command:
[SENSe:]FREQuency:CENTer:STEP:LINK on page 217
[SENSe:]FREQuency:CENTer:STEP:LINK:FACTor on page 218
[SENSe:]FREQuency:CENTer:STEP on page 217
(default:) Sets the step size for the center frequency to 10 % of the
demodulation bandwidth.
Sets the step size for the center frequency to 50 % of the demodulation bandwidth.
Sets the step size for the center frequency to a manually defined factor of the demodulation bandwidth. The "X-Factor" defines the percentage of the demodulation bandwidth.
Values between 1 % and 100 % in steps of 1 % are allowed. The
default setting is 10 %.
Sets the step size to the value of the center frequency and removes
the coupling of the step size to the demodulation bandwidth. The
used value is indicated in the "Value" field.
Defines a fixed step size for the center frequency. Enter the step size
in the "Value" field.
5.4 Trigger configuration
Access: "Overview" > "Trigger"
Triggering means to capture the interesting part of the signal. Choosing the right trigger
type and configuring all trigger settings correctly allows you to detect various incidents
in your demodulated signals.
Optionally, the trigger signal used by the R&S FSW can be output to a connected
device, and an external trigger signal from a connected device can be used by the
R&S FSW.
Trigger settings are identical to the base unit, except for the available trigger sources.
Gating is not available for Analog Modulation Analysis.
For background information on trigger settings, trigger output and working with external
triggers, see the R&S FSW User Manual.
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R&S®FSW-K7
Configuration
Trigger configuration
● Trigger source settings............................................................................................53
● Trigger input and output settings.............................................................................60
5.4.1 Trigger source settings
Access: "Overview" > "Trigger" > "Trigger Source" tab
Trigger Source...............................................................................................................53
└ Free Run.........................................................................................................54
└ External Trigger 1/2/3..................................................................................... 54
└ External Channel 3......................................................................................... 54
└ External Analog...............................................................................................55
└ I/Q Power........................................................................................................55
└ IF Power..........................................................................................................55
└ Baseband Power.............................................................................................56
└ Digital I/Q........................................................................................................ 56
└ FM (Offline) / AM (Offline) / PM (Offline) / RF (Offline)................................... 57
└ Time................................................................................................................57
└ RF Power........................................................................................................57
└ Power Sensor................................................................................................. 57
Trigger Level................................................................................................................. 57
Repetition Interval......................................................................................................... 58
Trigger Offset................................................................................................................ 58
Hysteresis..................................................................................................................... 58
Drop-Out Time...............................................................................................................59
Coupling........................................................................................................................59
Slope.............................................................................................................................59
Trigger Holdoff...............................................................................................................59
Trigger Source
In the R&S FSW AM/FM/PM Modulation Analysis application, the next measurement
can be triggered if the selected input signal exceeds the threshold specified using the
"Trigger Level" setting (see "Trigger Level" on page 57). Thus, a periodic signal
modulated onto the carrier frequency can be displayed. It is recommended that the
measurement time covers at least five periods of the audio signal.
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R&S®FSW-K7
Configuration
Trigger configuration
Remote command:
TRIGger[:SEQuence]:SOURce on page 239
Free Run ← Trigger Source
No trigger source is considered. Data acquisition is started manually or automatically
and continues until stopped explicitly.
Remote command:
TRIG:SOUR IMM, see TRIGger[:SEQuence]:SOURce on page 239
External Trigger 1/2/3 ← Trigger Source
Data acquisition starts when the TTL signal fed into the specified input connector
meets or exceeds the specified trigger level.
(See "Trigger Level" on page 57).
Note: The "External Trigger 1" softkey automatically selects the trigger signal from the
"TRIGGER 1 INPUT" connector on the front panel.
If the optional 2 GHz / 5 GHz bandwidth extension (B2000/B5000) is active, only Exter-
nal Channel 3 is supported.
If the optional 2 GHz / 5 GHz bandwidth extension (B2000/B5000) and the power split-
ter mode is active, only "External Analog" on page 55 is supported.
If the optional Oscilloscope Baseband Input is active, only "External Analog"
on page 55 is supported.
For details, see the "Instrument Tour" chapter in the R&S FSW Getting Started manual.
"External Trigger 1"
Trigger signal from the "TRIGGER 1 INPUT" connector.
"External Trigger 2"
Trigger signal from the "TRIGGER 2 INPUT / OUTPUT" connector.
Note: Connector must be configured for "Input" in the "Output" configuration
For R&S FSW85 models, "Trigger 2" is not available due to the second RF input connector on the front panel.
(See the R&S FSW user manual).
"External Trigger 3"
Trigger signal from the "TRIGGER 3 INPUT / OUTPUT" connector on
the rear panel.
Note: Connector must be configured for "Input" in the "Output" configuration.
(See R&S FSW user manual).
Remote command:
TRIG:SOUR EXT, TRIG:SOUR EXT2
TRIG:SOUR EXT3
See TRIGger[:SEQuence]:SOURce on page 239
External Channel 3 ← Trigger Source
Data acquisition starts when the signal fed into the "Ch3" input connector on the oscilloscope meets or exceeds the specified trigger level.
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R&S®FSW-K7
Configuration
Trigger configuration
Note: In previous firmware versions, the external trigger was connected to the "Ch2"
input on the oscilloscope. As of firmware version R&S FSW 2.30, the "Ch3" input on
the oscilloscope must be used!
This trigger source is only available if the optional 2 GHz / 5 GHz bandwidth extension
(R&S FSW-B2000/B5000) is active (see R&S FSW I/Q Analyzer and I/Q Input User
Manual).
Note: Since the external trigger uses a second channel on the oscilloscope, the maximum memory size, and thus record length, available for the input channel 1 may be
reduced by half. For details, see the oscilloscope's data sheet and documentation.
Remote command:
TRIG:SOUR EXT, see TRIGger[:SEQuence]:SOURce on page 239
External Analog ← Trigger Source
Data acquisition starts when the signal fed into the EXT TRIGGER INPUT connector
on the oscilloscope meets or exceeds the specified trigger level.
For details, see the R&S FSW I/Q Analyzer and I/Q Input User Manual.
Remote command:
TRIG:SOUR EXT, see TRIGger[:SEQuence]:SOURce on page 239
I/Q Power ← Trigger Source
This trigger source is not available if the optional "Digital Baseband" interface or
optional "Analog Baseband" interface is used for input.
Triggers the measurement when the magnitude of the sampled I/Q data exceeds the
trigger threshold.
The trigger bandwidth corresponds to the resolution bandwidth setting for data acquisition (see "Resolution Bandwidth" on page 63).
Remote command:
TRIG:SOUR IQP, see TRIGger[:SEQuence]:SOURce on page 239
IF Power ← Trigger Source
The R&S FSW starts capturing data as soon as the trigger level is exceeded around
the third intermediate frequency.
For frequency sweeps, the third IF represents the start frequency. The trigger threshold
depends on the defined trigger level, as well as on the RF attenuation and preamplification. A reference level offset, if defined, is also considered. The trigger bandwidth at
the intermediate frequency depends on the RBW and sweep type. For details on available trigger levels and trigger bandwidths, see the instrument data sheet.
For measurements on a fixed frequency (e.g. zero span or I/Q measurements), the
third IF represents the center frequency.
This trigger source is only available for RF input.
It is not available for input from the optional "Digital Baseband" interface or the optional
"Analog Baseband" interface.
The available trigger levels depend on the RF attenuation and preamplification. A refer-
ence level offset, if defined, is also considered.
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R&S®FSW-K7
Configuration
Trigger configuration
When using the optional 2 GHz / 5 GHz bandwidth extension (R&S FSW-B2000/
B5000) with an IF power trigger, the IF power trigger corresponds to a "width" trigger
on the oscilloscope, with a negative polarity and the range "longer". Thus, data acquisition starts when both of the following conditions apply to the signal fed into the CH1
input connector on the oscilloscope:
●
The power level has remained below the specified trigger level for a duration longer than the drop-out time.
●
The power level then rises above the specified trigger level.
For details, see "Basics on the 2 GHz / 5 GHz Bandwidth Extension" in the R&S FSW
I/Q Analyzer and I/Q Input User Manual.
For details on available trigger levels and trigger bandwidths, see the data sheet.
Remote command:
TRIG:SOUR IFP, see TRIGger[:SEQuence]:SOURce on page 239
Baseband Power ← Trigger Source
Defines triggering on the baseband power (for baseband input via the optional "Digital
Baseband" interface or the optional "Analog Baseband" interface).
For more information on the "Digital Baseband" interface or the "Analog Baseband"
interface, see the R&S FSW I/Q Analyzer and I/Q Input user manual.
Remote command:
TRIG:SOUR BBP, see TRIGger[:SEQuence]:SOURce on page 239
Digital I/Q ← Trigger Source
For applications that process I/Q data, such as the I/Q Analyzer or optional applications, and only if the optional "Digital Baseband" interface is available:
Defines triggering of the measurement directly via the "LVDS" connector. In the selection list, specify which general-purpose bit ("GP0" to "GP5") provides the trigger data.
Note: If the Digital I/Q enhanced mode is used, i.e. the connected device supports
transfer rates up to 200 Msps, only the general-purpose bits "GP0" and "GP1" are
available as a Digital I/Q trigger source.
The following table describes the assignment of the general-purpose bits to the LVDS
connector pins.
(For details on the LVDS connector, see the R&S FSW I/Q Analyzer User Manual.)
Table 5-1: Assignment of general-purpose bits to LVDS connector pins
Bit LVDS pin
GP0 SDATA4_P - Trigger1
GP1 SDATA4_P - Trigger2
*)
GP2
*)
GP3
*)
GP4
*)
GP5
*)
: not available for Digital I/Q enhanced mode
SDATA0_P - Reserve1
SDATA4_P - Reserve2
SDATA0_P - Marker1
SDATA4_P - Marker2
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R&S®FSW-K7
Configuration
Trigger configuration
Remote command:
TRIG:SOUR GP0, see TRIGger[:SEQuence]:SOURce on page 239
FM (Offline) / AM (Offline) / PM (Offline) / RF (Offline) ← Trigger Source
Triggers when the demodulated input signal exceeds the trigger level.
Remote command:
TRIGger[:SEQuence]:SOURce on page 239
Time ← Trigger Source
Triggers in a specified repetition interval.
See "Repetition Interval" on page 58.
Remote command:
TRIG:SOUR TIME, see TRIGger[:SEQuence]:SOURce on page 239
RF Power ← Trigger Source
Defines triggering of the measurement via signals which are outside the displayed
measurement range.
For this purpose, the instrument uses a level detector at the first intermediate frequency.
The resulting trigger level at the RF input depends on the RF attenuation and preamplification. For details on available trigger levels, see the instrument's data sheet.
Note: If the input signal contains frequencies outside of this range (e.g. for fullspan
measurements), the sweep can be aborted. A message indicating the allowed input
frequencies is displayed in the status bar.
A "Trigger Offset", "Trigger Polarity" and "Trigger Holdoff" (to improve the trigger stability) can be defined for the RF trigger, but no "Hysteresis".
This trigger source is not available for input from the optional "Digital Baseband" interface or the optional "Analog Baseband" interface. If the trigger source "RF Power" is
selected and digital I/Q or analog baseband input is activated, the trigger source is
automatically switched to "Free Run".
Remote command:
TRIG:SOUR RFP, see TRIGger[:SEQuence]:SOURce on page 239
Power Sensor ← Trigger Source
Uses an external power sensor as a trigger source. This option is only available if a
power sensor is connected and configured.
Note: For Rohde & Schwarz power sensors, the "Gate Mode" Lvl is not supported. The
signal sent by these sensors merely reflects the instant the level is first exceeded,
rather than a time period. However, only time periods can be used for gating in level
mode. Thus, the trigger impulse from the sensors is not long enough for a fully gated
measurement; the measurement cannot be completed.
Remote command:
TRIG:SOUR PSE, see TRIGger[:SEQuence]:SOURce on page 239
Trigger Level
Defines the trigger level for the specified trigger source.
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R&S®FSW-K7
Configuration
Trigger configuration
For details on supported trigger levels, see the instrument data sheet.
Remote command:
TRIGger[:SEQuence]:LEVel:IFPower on page 236
TRIGger[:SEQuence]:LEVel:IQPower on page 236
TRIGger[:SEQuence]:LEVel[:EXTernal<port>] on page 235
TRIGger[:SEQuence]:LEVel:RFPower on page 237
For analog baseband or digital baseband input only:
TRIGger[:SEQuence]:LEVel:BBPower on page 235
TRIGger[:SEQuence]:LEVel:AM:RELative on page 237
TRIGger[:SEQuence]:LEVel:AM[:ABSolute] on page 237
TRIGger[:SEQuence]:LEVel:FM on page 238
TRIGger[:SEQuence]:LEVel:PM on page 238
Repetition Interval
Defines the repetition interval for a time trigger.
The shortest interval is 2 ms.
Set the repetition interval to the exact pulse period, burst length, frame length or other
repetitive signal characteristic. If the required interval cannot be set with the available
granularity, configure a multiple of the interval that can be set. Thus, the trigger
remains synchronized to the signal.
Remote command:
TRIGger[:SEQuence]:TIME:RINTerval on page 241
Trigger Offset
Defines the time offset between the trigger event and the start of the sweep.
Offset > 0: Start of the sweep is delayed
Offset < 0: Sweep starts earlier (pretrigger)
For the "Time" trigger source, this function is not available.
Remote command:
TRIGger[:SEQuence]:HOLDoff[:TIME] on page 234
Hysteresis
Defines the distance in dB to the trigger level that the trigger source must exceed
before a trigger event occurs. Setting a hysteresis avoids unwanted trigger events
caused by noise oscillation around the trigger level.
This setting is only available for "IF Power" trigger sources. The range of the value is
between 3 dB and 50 dB with a step width of 1 dB.
When using the optional 2 GHz / 5 GHz bandwidth extension (R&S FSW-B2000/
B5000) with an IF power trigger, the hysteresis refers to the robust width trigger.
(For details see the R&S FSW I/Q Analyzer and I/Q Input User Manual.)
Remote command:
TRIGger[:SEQuence]:IFPower:HYSTeresis on page 235
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R&S®FSW-K7
Configuration
Trigger configuration
Drop-Out Time
Defines the time that the input signal must stay below the trigger level before triggering
again.
Note: For input from the optional "Analog Baseband" interface using the baseband
power trigger (BBP), the default drop out time is set to 100 ns. This avoids unintentional trigger events (as no hysteresis can be configured in this case).
When using the optional 2 GHz / 5 GHz bandwidth extension (R&S FSW-B2000/
B5000) with an IF power trigger, the drop-out time defines the width of the robust width
trigger. By default it is set to 1 μs. For external triggers, no drop-out time is available
when using the B2000/B5000 option.
(For details, see the R&S FSW I/Q Analyzer and I/Q Input User Manual.)
Remote command:
TRIGger[:SEQuence]:DTIMe on page 234
Coupling
If the selected trigger source is "IF Power" or "External Channel 3", you can configure
the coupling of the external trigger to the oscilloscope.
This setting is only available if the optional 2 GHz bandwidth extension is active.
"DC 50 Ω"
"DC 1 MΩ"
"AC"
Remote command:
TRIGger[:SEQuence]:OSCilloscope:COUPling on page 183
Slope
For all trigger sources except time, you can define whether triggering occurs when the
signal rises to the trigger level or falls down to it.
When using the optional 2 GHz / 5 GHz bandwidth extension (R&S FSW-B2000/
B5000) with an IF power trigger, only rising slopes can be detected.
(For details see the R&S FSW I/Q Analyzer and I/Q Input User Manual.)
Remote command:
TRIGger[:SEQuence]:SLOPe on page 238
Trigger Holdoff
Defines the minimum time (in seconds) that must pass between two trigger events.
Trigger events that occur during the holdoff time are ignored.
Remote command:
TRIGger[:SEQuence]:IFPower:HOLDoff on page 234
Direct connection with 50 Ω termination, passes both DC and AC
components of the trigger signal.
Direct connection with 1 MΩ termination, passes both DC and AC
components of the trigger signal.
Connection through capacitor, removes unwanted DC and very lowfrequency components.
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5.4.2 Trigger input and output settings
Configuration
Trigger configuration
Access: "Overview" > "Trigger" > "Trigger In/Out" tab
Trigger 2/3.....................................................................................................................60
└ Output Type.................................................................................................... 61
└ Level..................................................................................................... 61
└ Pulse Length.........................................................................................61
└ Send Trigger.........................................................................................61
Trigger 2/3
The trigger input and output functionality depends on how the variable "Trigger Input/
Output" connectors are used.
Note: Providing trigger signals as output is described in detail in the R&S FSW User
Manual.
"Trigger 1"
"Trigger 2"
"Trigger 3"
"Input"
"Output"
Remote command:
OUTPut<up>:TRIGger<tp>:DIRection on page 241
"Trigger 1" is input only.
Defines the usage of the variable "Trigger Input/Output" connector on
the front panel
(not available for R&S FSW85 models with 2 RF input connectors)
Defines the usage of the variable "Trigger 3 Input/Output" connector
on the rear panel
The signal at the connector is used as an external trigger source by
the R&S FSW. Trigger input parameters are available in the "Trigger"
dialog box.
The R&S FSW sends a trigger signal to the output connector to be
used by connected devices.
Further trigger parameters are available for the connector.
Note: For offline AF or RF triggers, no output signal is provided.
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Output Type ← Trigger 2/3
Type of signal to be sent to the output
"Device Trig-
gered"
"Trigger
Armed"
(Default) Sends a trigger when the R&S FSW triggers.
Sends a (high level) trigger when the R&S FSW is in "Ready for trigger" state.
This state is indicated by a status bit in the STATus:OPERation register (bit 5), as well as by a low-level signal at the "AUX" port (pin 9).
For details, see the description of the STATus:OPERation register
in the R&S FSW User Manual and the description of the "AUX" port in
the R&S FSW Getting Started manual.
Configuration
Trigger configuration
"User Defined"
Remote command:
OUTPut<up>:TRIGger<tp>:OTYPe on page 242
Level ← Output Type ← Trigger 2/3
Defines whether a high (1) or low (0) constant signal is sent to the trigger output connector (for "Output Type": "User Defined".
The trigger pulse level is always opposite to the constant signal level defined here. For
example, for "Level" = "High", a constant high signal is output to the connector until you
select the Send Trigger function. Then, a low pulse is provided.
Remote command:
OUTPut<up>:TRIGger<tp>:LEVel on page 242
Pulse Length ← Output Type ← Trigger 2/3
Defines the duration of the pulse (pulse width) sent as a trigger to the output connector.
Remote command:
OUTPut<up>:TRIGger<tp>:PULSe:LENGth on page 243
Sends a trigger when you select the "Send Trigger" button.
In this case, further parameters are available for the output signal.
Send Trigger ← Output Type ← Trigger 2/3
Sends a user-defined trigger to the output connector immediately.
Note that the trigger pulse level is always opposite to the constant signal level defined
by the output Level setting. For example, for "Level" = "High", a constant high signal is
output to the connector until you select the "Send Trigger" function. Then, a low pulse
is sent.
Which pulse level is sent is indicated by a graphic on the button.
Remote command:
OUTPut<up>:TRIGger<tp>:PULSe:IMMediate on page 243
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5.5 Data acquisition
Configuration
Data acquisition
Access: "Overview" > "Data Acquisition"
You configure how data is acquired and then demodulated in the "Data Acquisition"
dialog box.
MSRA/MSRT operating mode
In MSRA/MSRT operating mode, only the MSRA/MSRT primary channel actually captures data from the input signal. The data acquisition settings for the R&S FSW
AM/FM/PM Modulation Analysis application in MSRA/MSRT mode define the analysis
interval.
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 Real-Time Spectrum Application and MSRT Operating Mode User Manual.
● Bandwidth settings..................................................................................................62
● Sweep settings........................................................................................................64
5.5.1 Bandwidth settings
Access: "Overview" > "Data Acquisition" > "Bandwidth" tab
The bandwidth settings define which parts of the input signal are acquired and then
demodulated.
Demodulation Bandwidth.............................................................................................. 62
Demodulation Filter.......................................................................................................63
Measurement Time (AQT).............................................................................................63
Capture Offset...............................................................................................................63
Resolution Bandwidth................................................................................................... 63
Demodulation Bandwidth
Defines the demodulation bandwidth of the measurement. The demodulation bandwidth determines the sample rate with which the input signal is captured and analyzed.
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Configuration
Data acquisition
For recommendations on finding the correct demodulation bandwidth, see Chapter 4.2,
"Demodulation bandwidth", on page 28.
For details on the relation between demodulation bandwidth and sample rate, refer to
Chapter 4.3, "Sample rate and demodulation bandwidth", on page 29.
Remote command:
[SENSe:]BWIDth:DEMod on page 231
Demodulation Filter
Defines the filter to be used for demodulation.
For details on sample rates, measurement times and trigger offsets for various demod-
ulation bandwidths when using a Gaussian filter, see Chapter 4.3, "Sample rate and
demodulation bandwidth", on page 29.
"Flat"
"Gauss"
Remote command:
[SENSe:]BWIDth:DEMod:TYPE on page 231
Default
Optimizes the settling behavior of the filter
Measurement Time (AQT)
Defines how long data is acquired for demodulation.
Remote command:
[SENSe:]ADEMod:MTIMe on page 229
Capture Offset
This setting is only available for secondary applications in MSRA / MSRT operating
mode. It has a similar effect as the trigger offset in other measurements: it defines the
time offset between the capture buffer start and the start of the extracted secondary
application data.
In MSRA mode, the offset must be a positive value, as the capture buffer starts at the
trigger time = 0.
In MSRT mode, the offset can be negative if a pretrigger time is defined.
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 Real-Time Spectrum
Application and MSRT Operating Mode User Manual.
Remote command:
[SENSe:]MSRA:CAPTure:OFFSet on page 374
MSRT mode:
[SENSe:]RTMS:CAPTure:OFFSet on page 376
Resolution Bandwidth
Defines the resolution bandwidth for data acquisition. The available range is specified
in the data sheet.
Remote command:
[SENSe:]BANDwidth[:RESolution] on page 231
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5.5.2 Sweep settings
Configuration
Data acquisition
Access: "Overview" > "Data Acquisition" > "Sweep" tab
The sweep settings define how often data from the input signal is acquired and then
demodulated.
Continuous Sweep / Run Cont......................................................................................64
Single Sweep / Run Single............................................................................................65
Continue Single Sweep.................................................................................................65
Refresh (MSRA / MSRT only).......................................................................................66
Measurement Time (AQT).............................................................................................66
Sweep Points................................................................................................................ 66
Sweep/Average Count.................................................................................................. 66
Select Frame.................................................................................................................66
Continue Frame............................................................................................................ 67
Frame Count................................................................................................................. 67
Clear Spectrogram........................................................................................................67
Continuous Sweep / Run Cont
After triggering, starts the sweep and repeats it continuously until stopped. This is the
default setting.
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Configuration
Data acquisition
While the measurement is running, the "Continuous Sweep" softkey and the [RUN
CONT] key are highlighted. The running measurement can be aborted by selecting the
highlighted softkey or key again. The results are not deleted until a new measurement
is started.
Note: Sequencer. If the Sequencer is active, the "Continuous Sweep" softkey only controls the sweep mode for the currently selected channel. However, the sweep mode
only takes effect the next time the Sequencer activates that channel, and only for a
channel-defined sequence. In this case, a channel in continuous sweep mode is swept
repeatedly.
If the Sequencer is active in MSRT mode, the "Continuous Sweep" function does not
start data capturing. It merely affects trace averaging over multiple sequences. In this
case, trace averaging is performed.
Furthermore, the [RUN CONT] key controls the Sequencer, not individual sweeps.
[RUN CONT] starts the Sequencer in continuous mode.
For details on the Sequencer, see the R&S FSW User Manual.
Remote command:
INITiate<n>:CONTinuous on page 268
Single Sweep / Run Single
After triggering, starts the number of sweeps set in "Sweep Count". The measurement
stops after the defined number of sweeps has been performed.
While the measurement is running, the "Single Sweep" softkey and the [RUN SINGLE]
key are highlighted. The running measurement can be aborted by selecting the highlighted softkey or key again.
Note: Sequencer. If the Sequencer is active, the "Single Sweep" softkey only controls
the sweep mode for the currently selected channel. However, the sweep mode only
takes effect the next time the Sequencer activates that channel, and only for a channel-defined sequence. In this case, the Sequencer sweeps a channel in single sweep
mode only once.
If the Sequencer is active in MSRT mode, the "Single Sweep" function does not start
data capturing. It merely affects trace averaging over multiple sequences. In this case,
no trace averaging is performed.
Furthermore, the [RUN SINGLE] key controls the Sequencer, not individual sweeps.
[RUN SINGLE] starts the Sequencer in single mode.
If the Sequencer is off, only the evaluation for the currently displayed channel is updated.
For details on the Sequencer, see the R&S FSW User Manual.
Remote command:
INITiate<n>[:IMMediate] on page 269
Continue Single Sweep
After triggering, repeats the number of sweeps set in "Sweep Count", without deleting
the trace of the last measurement.
While the measurement is running, the "Continue Single Sweep" softkey and the [RUN
SINGLE] key are highlighted. The running measurement can be aborted by selecting
the highlighted softkey or key again.
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Configuration
Data acquisition
Remote command:
INITiate<n>:CONMeas on page 268
Refresh (MSRA / MSRT only)
This function is only available if the Sequencer is deactivated and only for MSRA /
MSRT secondary applications.
The data in the capture buffer is re-evaluated by the currently active secondary application only. The results for any other secondary applications remain unchanged.
This is useful, for example, after evaluation changes have been made or if a new
sweep was performed from another secondary application. In this case, only that secondary application is updated automatically after data acquisition.
Note: To update all active secondary applications at once, use the "Refresh All" function in the "Sequencer" menu.
Remote command:
INITiate<n>:REFResh on page 269
Measurement Time (AQT)
Defines how long data is acquired for demodulation.
Remote command:
[SENSe:]ADEMod:MTIMe on page 229
Sweep Points
Defines the number of measured values to be collected during one sweep.
All values from 101 to 100001 can be set. The default value is 1001 sweep points.
Remote command:
[SENSe:]SWEep[:WINDow<n>]:POINts on page 232
Sweep/Average Count
Defines the number of sweeps to be performed in the single sweep mode. Values from
0 to 200000 are allowed. If the values 0 or 1 are set, one sweep is performed.
The sweep count is applied to all the traces in all diagrams.
If the trace modes "Average", "Max Hold" or "Min Hold" are set, this value also deter-
mines the number of averaging or maximum search procedures.
In continuous sweep mode, if "Sweep Count" = 0 (default), averaging is performed
over 10 sweeps. For "Sweep Count" =1, no averaging, maxhold or minhold operations
are performed.
Remote command:
[SENSe:]SWEep:COUNt on page 232
[SENSe:]AVERage<n>:COUNt on page 305
Select Frame
Selects a specific frame, loads the corresponding trace from the memory, and displays
it in the Spectrum window.
Note that activating a marker or changing the position of the active marker automatically selects the frame that belongs to that marker.
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Configuration
Demodulation display
This function is only available in single sweep mode or if the sweep is stopped, and
only if a spectrogram is selected.
The most recent frame is number 0, all previous frames have a negative number.
For more details, see the R&S FSW User Manual.
Remote command:
CALCulate<n>:SPECtrogram:FRAMe:SELect on page 295
Continue Frame
Determines whether the results of the previous sweeps are included in the analysis of
the next sweeps for trace modes "Max Hold", "Min Hold", and "Average".
This function is available in single sweep mode only.
●
On
When the average or peak values are determined for the new sweep, the results of
the previous sweeps in the spectrogram are also considered.
●
Off
The average or peak values are determined from the results of the newly swept
frames only.
Remote command:
CALCulate<n>:SPECtrogram:CONTinuous on page 294
Frame Count
Determines how many frames are plotted during a single sweep (as opposed to a continuous sweep). The maximum number of possible frames depends on the history
depth (see "History Depth" on page 102).
Remote command:
CALCulate<n>:SPECtrogram:FRAMe:COUNt on page 294
Clear Spectrogram
Resets the spectrogram result display and clears the history buffer.
This function is only available if a spectrogram is selected.
Remote command:
CALCulate<n>:SPECtrogram:CLEar[:IMMediate] on page 294
5.6 Demodulation display
Access: "Overview" > "Demod/Display"
The demodulated signal can be displayed using various evaluation methods. All evaluation methods available for the Analog Modulation Analysis application are displayed in
the evaluation bar in SmartGrid mode when you do one of the following:
Up to six evaluation methods can be displayed simultaneously in separate windows.
The Analog Modulation Analysis evaluation methods are described in Chapter 3, "Mea-
surements and result displays", on page 14.
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5.7 Demodulation
Configuration
Demodulation
For details on working with the SmartGrid, see the R&S FSW Getting Started manual.
Access: "Overview" > "Demod Settings"
Or: "Meas Setup" > "Demod"
● Basic demodulation measurement parameters (Demod)........................................68
● Demodulation spectrum.......................................................................................... 71
● AF filter....................................................................................................................74
● Scaling.................................................................................................................... 78
● Units........................................................................................................................82
● Result table settings................................................................................................83
● Settling time............................................................................................................ 85
5.7.1 Basic demodulation measurement parameters (Demod)
Access: "Overview" > "Demod Settings" > "Demod"
Or: "Meas Setup" > "Demod" > "Demod" tab
The basic demodulation measurement parameters define how the measurement is
performed.
Squelch State................................................................................................................69
Squelch Level................................................................................................................69
AF Coupling.................................................................................................................. 69
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Configuration
Demodulation
Selected Trace..............................................................................................................69
Time Domain Zoom.......................................................................................................70
└ State................................................................................................................70
└ Start................................................................................................................ 70
└ Length.............................................................................................................70
└ Time per Division............................................................................................ 70
Zero Phase Reference Position (PM Time Domain only)..............................................71
Phase Wrap On/Off (PM Time Domain only)................................................................ 71
Squelch State
Activates the squelch function, that is: if the signal falls below a defined threshold, the
demodulated data is automatically set to 0. This is useful, for example, to avoid
demodulation noise during transmission breaks.
This function is only available for FM demodulation.
Remote command:
[SENSe:]ADEMod:SQUelch[:STATe] on page 246
Squelch Level
Defines the level threshold below which the demodulated data is set to 0 if squelching
is enabled. The squelch level is an absolute value.
Remote command:
[SENSe:]ADEMod:SQUelch:LEVel on page 246
AF Coupling
Controls the automatic correction of the frequency offset and phase offset of the input
signal:
This function is only available for FM or PM time domain evaluations.
●
FM time evaluation
If DC is selected, the absolute frequency is displayed. That means, an input signal
with an offset relative to the center frequency is not displayed symmetrically to the
zero line.
If AC is selected, the frequency offset is automatically corrected, i.e. the trace is
always symmetric to the zero line.
●
PM time evaluation
If DC is selected, the phase runs according to the existing frequency offset. In addition, the DC signal contains a phase offset of ± π.
If AC is selected, the frequency offset and phase offset are automatically corrected,
i.e. the trace is always symmetric to the zero line.
Remote command:
[SENSe:]ADEMod<n>:AF:COUPling on page 244
Selected Trace
Defines the trace used to determine the results in the "Result Summary".
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Configuration
Demodulation
Time Domain Zoom
Using the time domain zoom, the demodulated data for a particular time span is extracted and displayed in more detail. Time domain zoom is useful if the measurement time
is very large and thus each sweep point represents a large time span. The time domain
zoom function distributes the available sweep points only among the time span defined
by the zoom area length. The time span displayed per division of the diagram is
decreased. Thus, the display of the extracted time span becomes more precise. Note
that the time domain zoom area affects not only the diagram display, but the entire
evaluation for the current window.
This function is only available for evaluations in the time domain.
Tip: In addition to the Time Domain Zoom, a graphical zoom is available for all diagram
evaluations. However, the graphical zoom is useful only if more measured values than
trace points are available. The (time) span represented by each measurement point
remains the same.
For details see the R&S FSW User Manual.
State ← Time Domain Zoom
Activates or deactivates the time domain zoom mode.
"On"
"Off"
Remote command:
[SENSe:]ADEMod<n>:ZOOM[:STATe] on page 248
Activates the time domain zoom.
Deactivates the time domain zoom and restores the original display. If
more measured values than measurement points are available, several measured values are combined in one measurement point
according to the method of the selected trace detector.
Start ← Time Domain Zoom
Defines the start time for the time domain zoom area. For spectrum evaluations, the
start time is always 0.
Remote command:
[SENSe:]ADEMod<n>:ZOOM:STARt on page 248
Length ← Time Domain Zoom
Defines the length of the time domain zoom area. Enter the length as a time value
manually, or use the "Auto" setting to set the length to the current number of sweep
points automatically.
Remote command:
[SENSe:]ADEMod<n>:ZOOM:LENGth on page 247
[SENSe:]ADEMod<n>:ZOOM:LENGth:MODE on page 247
Time per Division ← Time Domain Zoom
Enables the "Time Domain Zoom" function and defines the zoom area length in one
step. The width of the zoom display is divided into 10 divisions; thus, by entering the
time that is displayed in each division, you indirectly define the zoom area length
("Time per Division" * 10). The starting point of the zoom area is determined automatically. To specify the starting point manually, use the Start setting.
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Configuration
Demodulation
The "Time per Division" softkey is available from the main "AM FM PM Analog Demod"
menu.
Zero Phase Reference Position (PM Time Domain only)
Defines the position in time at which the phase of the PM-demodulated signal is set to
0 rad. In the default setting, the time of the first measured value is set to 0 rad. You can
define a different position manually, or select the time of the last measured value as the
reference position. The time of the last measured value corresponds to the acquisition
time, considering the trigger event and trigger offset, if applicable. If the acquisition
time or the trigger values are changed, the reference position is automatically adapted.
This setting is only available for PM time domain displays with DC coupling.
Remote command:
[SENSe:]ADEMod:PM:RPOint[:X] on page 245
[SENSe:]ADEMod:PM:RPOint[:X]:MODE on page 245
Phase Wrap On/Off (PM Time Domain only)
Activates/deactivates the phase wrap.
On The phase is displayed in the range ±180° (± Π). For example, if the phase exceeds +180°,
360° is subtracted from the phase value, with the display thus showing >-180°.
Off The phase is not wrapped.
This setting is only available for PM time domain displays with DC coupling.
Remote command:
CALC:FORM PHAS/CALC:FORM UPH, see CALCulate<n>:FORMat on page 246
5.7.2 Demodulation spectrum
Access: "Overview" > "Demod Settings" > "Spectrum"
Or: "Meas Setup" > "Demod" > "Spectrum" tab
The demodulation spectrum defines which span of the demodulated data is evaluated.
Depending on the evaluation (AF or RF display), the settings vary.
● AF evaluation.......................................................................................................... 71
● RF evaluation..........................................................................................................73
5.7.2.1 AF evaluation
Access: "Overview" > "Demod Settings" > "Spectrum"
Or: "Meas Setup" > "Demod" > "Spectrum" tab
These settings are only available for AF Spectrum evaluations, not in the time domain.
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Configuration
Demodulation
AF Center......................................................................................................................72
AF Start.........................................................................................................................72
AF Stop......................................................................................................................... 72
AF Span........................................................................................................................ 72
AF Full Span................................................................................................................. 73
AF Center
Defines the center frequency of the demodulated data to evaluate.
Remote command:
[SENSe:]ADEMod:AF:CENTer on page 249
AF Start
Defines the start frequency of the demodulated data to evaluate.
Remote command:
[SENSe:]ADEMod:AF:STARt on page 250
AF Stop
Defines the stop frequency of the demodulated data to evaluate.
The maximum AF stop frequency corresponds to half the demodulation bandwidth.
Remote command:
[SENSe:]ADEMod:AF:STOP on page 250
AF Span
Defines the span (around the center frequency) of the demodulated data to evaluate.
The maximum span is DBW/2.
Remote command:
[SENSe:]ADEMod:AF:SPAN on page 249
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5.7.2.2 RF evaluation
Configuration
Demodulation
AF Full Span
Sets the span (around the center frequency) of the demodulated data to the maximum
of DBW/2.
Remote command:
[SENSe:]ADEMod:AF:SPAN:FULL on page 249
Access: "Overview" > "Demod Settings" > "Spectrum"
Or: "Meas Setup" > "Demod" > "Spectrum" tab
These settings are only available for RF evaluation, both in time and frequency
domain. Note that for RF data the center frequency and demodulation bandwidth correspond to the settings defined in the "Input" and "Data Acquisition" configuration.
Center Frequency......................................................................................................... 73
Span..............................................................................................................................74
Demodulation Bandwidth.............................................................................................. 74
RF Full Span................................................................................................................. 74
Center Frequency
Defines the center frequency of the signal in Hertz.
The allowed range of values for the center frequency depends on the frequency span.
span > 0: span
f
and span
max
/2 ≤ f
min
depend on the instrument and are specified in the data sheet.
min
center
≤ f
max
– span
min
/2
Remote command:
[SENSe:]FREQuency:CENTer on page 217
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Configuration
Demodulation
Span
Defines the frequency span. The center frequency is kept constant. The following
range is allowed:
span = 0: 0 Hz
span >0:
span
and f
f
min
max
and span
max
≤ f
span
=DBW/2
≤ f
max
are specified in the data sheet.
min
Remote command:
[SENSe:]ADEMod:SPECtrum:SPAN[:MAXimum] on page 251
[SENSe:]ADEMod:SPECtrum:SPAN:ZOOM on page 251
Demodulation Bandwidth
Defines the demodulation bandwidth of the measurement. The demodulation bandwidth determines the sample rate with which the input signal is captured and analyzed.
For recommendations on finding the correct demodulation bandwidth, see Chapter 4.2,
"Demodulation bandwidth", on page 28.
For details on the relation between demodulation bandwidth and sample rate, refer to
Chapter 4.3, "Sample rate and demodulation bandwidth", on page 29.
Remote command:
[SENSe:]BWIDth:DEMod on page 231
RF Full Span
Sets the span (around the center frequency) of the RF data to be evaluated to the
demodulation bandwidth.
Remote command:
[SENSe:]ADEMod:SPECtrum:SPAN[:MAXimum] on page 251
5.7.3 AF filter
Access: "Overview" > "Demod Settings" > "AF Filter"
Or: "Meas Setup" > "Demod" > "AF Filter" tab
The AF filter reduces the evaluated bandwidth of the demodulated signal and can
define a weighting function.
AF filters are only available for AF evaluations, not for RF evaluation.
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Configuration
Demodulation
If a high pass or low pass AF filter is defined, the filter is indicated by a vertical red line
in the spectrum display.
High Pass......................................................................................................................75
Low Pass.......................................................................................................................76
Weighting...................................................................................................................... 76
Deemphasis.................................................................................................................. 77
Deactivating all AF Filters............................................................................................. 77
High Pass
Defines a high pass filter with the given limit to separate the DC component. The filters
are indicated by the 3 dB cutoff frequency. The 50 Hz and 300 Hz filters are designed
as 2nd-order Butterworth filter (12 dB/octave). The 20 Hz filter is designed as 3rd-order
Butterworth filter (18 dB/octave).
The high pass filters are active in the following demodulation bandwidth range:
None No AF Filter used (default)
20 Hz 100 Hz ≤ demodulation bandwidth ≤ 1.6 MHz
50 Hz: 200 Hz ≤ demodulation bandwidth ≤ 3 MHz
300 Hz: 800 Hz ≤ demodulation bandwidth ≤ 8 MHz
Manual: A high pass filter with the manually defined frequency is used.
Note: If online demodulation output is active, the predefined (fixed) filters are not available. In this case, the frequency for the high pass filter must be defined manually (see
also Chapter 5.8.2, "Analog demod output settings", on page 88).
If a filter was already configured when online demodulation output is activated, it is
replaced by a manual filter that provides corresponding results, if possible.
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Demodulation
Remote command:
[SENSe:]FILTer<n>:HPASs[:STATe] on page 255
[SENSe:]FILTer<n>:HPASs:FREQuency[:ABSolute] on page 254
[SENSe:]FILTer<n>:HPASs:FREQuency:MANual on page 254
Low Pass
Defines a low pass filter type. Relative and absolute low pass filter are available.
●
Absolute low pass filters:
Absolute filters are indicated by the 3 dB cutoff frequency. The 3 kHz, 15 kHz and
23 kHz filters are designed as 5th-order Butterworth filters (30 dB/octave). The 150
kHz filter is designed as 8th-order Butterworth filter (48 dB/octave).
The absolute low pass filters are active in the following demodulation bandwidth
range:
Filter type Demodulation bandwidth
3 kHz: 6.4 kHz ≤ demodulation bandwidth ≤ 3 MHz
15 kHz: 50 kHz ≤ demodulation bandwidth ≤ 8 MHz
23 kHz 50 kHz ≤ demodulation bandwidth ≤ 18 MHz
150 kHz: 400 kHz ≤ demodulation bandwidth ≤ 8 MHz
Manual: A low pass filter with the manually defined frequency is used.
Note: If online demodulation output is active, the predefined (fixed) filters are not available. In this case, the frequency for the low pass filter must be defined manually (see
also Chapter 5.8.2, "Analog demod output settings", on page 88).
If a filter was already configured when online demodulation output is activated, it is
replaced by a manual filter that provides corresponding results, if possible.
●
Relative low pass filters:
Relative filters (3 dB) can be selected in % of the demodulation bandwidth. The filters are designed as 5th-order Butterworth filter (30 dB/octave) and active for all
demodulation bandwidths.
●
"NONE" deactivates the AF low pass filter (default).
Remote command:
[SENSe:]FILTer<n>:LPASs[:STATe] on page 256
[SENSe:]FILTer<n>:LPASs:FREQuency[:ABSolute] on page 255
[SENSe:]FILTer<n>:LPASs:FREQuency:RELative on page 256
[SENSe:]FILTer<n>:LPASs:FREQuency:MANual on page 256
Weighting
Selects a weighting AF filter. By default, no weighting filter is active.
"A weighted"
Switches on the A weighted filter. The weighting filter is active in the
following demodulation bandwidth range:
100 kHz ≤ demodulation bandwidth ≤ 800 kHz
"CCITT"
Switches on a CCITT P.53 weighting filter. The weighting filter is
active in the following demodulation bandwidth range:
20 kHz ≤ demodulation bandwidth ≤ 3 MHz
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Demodulation
"CCIR weighted"
Switches on the CCIR weighted filter. The weighting filter is active in
the following demodulation bandwidth range:
100 kHz ≤ demodulation bandwidth ≤ 3.0 MHz
"CCIR
unweighted"
Switches on the CCIR unweighted filter, which is the combination of
the 20 Hz highpass and 23 kHz low pass filter. The weighting filter is
active in the following demodulation bandwidth range:
50 kHz ≤ demodulation bandwidth ≤ 1.6 MHz
Remote command:
[SENSe:]FILTer<n>:CCITt[:STATe] on page 253
[SENSe:]FILTer<n>:CCIR[:UNWeighted][:STATe] on page 253
[SENSe:]FILTer<n>:CCIR:WEIGhted[:STATe] on page 252
[SENSe:]FILTer<n>:AWEighted[:STATe] on page 252
Deemphasis
Activates a deemphasis filter with the given time constant.
Sometimes a modulated signal is extorted by a pre-emphasis filter before transmission,
for example to eliminate frequencies that are more prone to interferences. In this case,
the emphasis function must be reversed after demodulation, which is done by the
deemphasis filter.
The deemphasis filter is active in the following demodulation bandwidth range:
25 µs: 25 kHz ≤ demodulation bandwidth ≤ 40 MHz
50 µs: 6.4 kHz ≤ demodulation bandwidth ≤ 18 MHz
75 µs: 6.4 kHz ≤ demodulation bandwidth ≤ 18 MHz
750 µs: 800 Hz ≤ demodulation bandwidth ≤ 3 MHz
Depending on the deemphasis filter, a minimum demodulation bandwidth is required
for an error less than 0.5 dB, up to a maximum AF frequency. The following table
shows the dependencies.
Deemphasis [us] 25 µs 50 µs 75 µs 750 µs
Max. AF frequency 25 kHz 12 kHz 8 kHz 800 Hz
Required demodulation bandwidth ≥ 200 kHz ≥ 100 kHz ≥ 50 kHz ≥ 6.4 kHz
For higher AF frequencies, the demodulation bandwidth must be increased.
Remote command:
[SENSe:]FILTer<n>:DEMPhasis[:STATe] on page 254
[SENSe:]FILTer<n>:DEMPhasis:TCONstant on page 253
Deactivating all AF Filters
The "All Filter Off" button deactivates all AF filters for the selected evaluation.
Remote command:
[SENSe:]FILTer<n>:AOFF on page 252
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5.7.4 Scaling
5.7.4.1 AF evaluation
Configuration
Demodulation
Access: "Overview" > "Demod Settings" > "Scaling"
Or: "Meas Setup" > "Demod" > "Scaling" tab
The scaling parameters define the range of the demodulated data to be displayed.
● AF evaluation.......................................................................................................... 78
● RF evaluation..........................................................................................................80
Access: "Overview" > "Demod Settings" > "Scaling"
Or: "Meas Setup" > "Demod" > "Scaling" tab
These settings are only available for AF evaluations.
Dev per Division/ dB per Division..................................................................................78
Reference Value Position..............................................................................................79
Reference Value............................................................................................................79
AF Coupling.................................................................................................................. 79
Deviation....................................................................................................................... 80
AF Auto Scale............................................................................................................... 80
Dev per Division/ dB per Division
Defines the modulation depth or the phase deviation or frequency deviation per division (logarithmic: 0.1 dB to 20 dB):
AM display: 0.0001 % to 1000 %
FM display: 10 mHz/div to 100 MHz/div
PM display: 0.0001 rad/div to 1000 rad/div
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Demodulation
Note: The value defined per division refers to the default display of 10 divisions on the
y-axis. If fewer divisions are displayed (e.g. because the window is reduced in height),
the range per division is increased. Thus, the same result range is displayed in the
smaller window. In this case, the per division value does not correspond to the actual
display.
Remote command:
DISPlay[:WINDow<n>][:SUBWindow<w>]:TRACe<t>:Y[:SCALe]:PDIVision
on page 226
Reference Value Position
Determines the position of the reference value for the modulation depth or the phase
deviation or frequency deviation on the y-axis of the diagram.
The position is entered as a percentage of the diagram height with 100 % corresponding to the upper diagram border. The default setting is 50 % (diagram center) for the
AF time evaluations and 100 % (upper diagram border) for the AF spectrum evaluations.
Remote command:
DISPlay[:WINDow<n>][:SUBWindow<w>]:TRACe<t>:Y[:SCALe]:RPOSition
on page 227
Reference Value
Determines the modulation depth or the phase deviation or the frequency deviation at
the reference line of the y-axis. The reference value can be set specifically for each
evaluation.
●
AF time display
The trace display takes individual frequency/phase offsets into account (in contrast,
the AF Coupling setting permits automatic correction by the average frequency/
phase offset of the signal, and therefore cannot be activated simultaneously).
●
AF spectrum display
In the default setting, the reference value defines the modulation depth or the
FM/PM deviation at the upper diagram border.
Possible values:
●
AM: 0 and ± 10000 %
●
FM: 0 and ± 10 MHz
●
PM: 0 and ± 10000 rad
Note: The reference value for the AF range in the window title bar is displayed with
respect to the defined reference position. The position can vary for different windows.
For time domain and frequency domain windows, for example, a different reference
value can be displayed, although the same reference is actually used (but the positions
vary).
Remote command:
DISPlay[:WINDow<n>][:SUBWindow<w>]:TRACe<t>:Y[:SCALe]:RVALue
on page 257
AF Coupling
Controls the automatic correction of the frequency offset and phase offset of the input
signal:
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Demodulation
This function is only available for FM or PM time domain evaluations.
●
FM time evaluation
If DC is selected, the absolute frequency is displayed. That means, an input signal
with an offset relative to the center frequency is not displayed symmetrically to the
zero line.
If AC is selected, the frequency offset is automatically corrected, i.e. the trace is
always symmetric to the zero line.
●
PM time evaluation
If DC is selected, the phase runs according to the existing frequency offset. In addition, the DC signal contains a phase offset of ± π.
If AC is selected, the frequency offset and phase offset are automatically corrected,
i.e. the trace is always symmetric to the zero line.
Remote command:
[SENSe:]ADEMod<n>:AF:COUPling on page 244
Deviation
Switches between logarithmic and linear display of the modulation depth or the phase
deviation or the frequency deviation.
Remote command:
DISPlay[:WINDow<n>][:SUBWindow<w>]:TRACe<t>:Y:SPACing on page 227
AF Auto Scale
Activates automatic scaling of the y-axis for AF measurements. RF power and RF
spectrum measurements are not affected by the auto-scaling.
Remote command:
[SENSe:]ADJust:SCALe[:Y]:AUTO[:CONTinuous] on page 266
5.7.4.2 RF evaluation
Access: "Overview" > "Demod Settings" > "Scaling"
Or: "Meas Setup" > "Demod" > "Scaling" tab
These settings are only available for RF evaluations and the "result summary".
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Demodulation
Range............................................................................................................................81
Ref Level Position......................................................................................................... 81
Auto Scale Once........................................................................................................... 81
Scaling.......................................................................................................................... 82
Range
Defines the displayed y-axis range in dB.
The default value is 100 dB.
For Analog Modulation Analysis measurements, time domain scaling is defined in Hz
(default: 500 kHz).
Remote command:
DISPlay[:WINDow<n>][:SUBWindow<w>]:TRACe<t>:Y[:SCALe] on page 225
Ref Level Position
Defines the reference level position, i.e. the position of the maximum AD converter
value on the level axis in %.
0 % corresponds to the lower and 100 % to the upper limit of the diagram.
Values from -120 % to +600 % are available. Larger values are useful for small scales,
such as a power range of 10 dB or 20 dB, and low signal levels, for example 60 dB
below the reference level. In this case, large reference level position values allow you
to see the trace again.
Only available for RF measurements.
Remote command:
DISPlay[:WINDow<n>][:SUBWindow<w>]:TRACe<t>:Y[:SCALe]:RPOSition
on page 227
Auto Scale Once
Automatically determines the optimal range and reference level position to be displayed for the current measurement settings.
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Demodulation
The display is only set once; it is not adapted further if the measurement settings are
changed again.
Remote command:
DISPlay[:WINDow<n>][:SUBWindow<w>]:TRACe<t>:Y[:SCALe]:AUTO ONCE
on page 226
Scaling
Defines the scaling method for the y-axis.
"Logarithmic"
"Linear with
Unit"
"Linear Percent"
"Absolute"
"Relative"
Remote command:
DISPlay[:WINDow<n>][:SUBWindow<w>]:TRACe<t>:Y:SPACing on page 227
DISPlay[:WINDow<n>][:SUBWindow<w>]:TRACe<t>:Y[:SCALe]:MODE
on page 226
Logarithmic scaling (only available for logarithmic units - dB..., and A,
V, Watt)
Linear scaling in the unit of the measured signal
Linear scaling in percentages from 0 to 100
The labeling of the level lines refers to the absolute value of the reference level (not available for "Linear Percent")
The scaling is in dB, relative to the reference level (only available for
logarithmic units - dB...). The upper line of the grid (reference level) is
always at 0 dB.
5.7.5 Units
Access: "Overview" > "Demod Settings" > "Unit"
Or: "Meas Setup" > "Demod" > "Unit" tab
The units define how the demodulated data is displayed.
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Demodulation
Phase Unit (Rad/Deg)...................................................................................................83
THD Unit (%/ DB)..........................................................................................................83
Relative Unit..................................................................................................................83
Phase Unit (Rad/Deg)
Sets the phase unit to rad or deg for displaying PM signals.
Remote command:
UNIT<n>:ANGLe on page 258
THD Unit (%/ DB)
Sets the unit to percent or DB for the calculation of the THD (in the "Result Summary").
Remote command:
UNIT<n>:THD on page 258
Relative Unit
Defines the unit for relative demodulation results (see Chapter 5.7.6, "Result table set-
tings", on page 83).
Remote command:
CONFigure:ADEMod:RESults:UNIT on page 261
5.7.6 Result table settings
Access: "Overview" > "Demod Settings" > "Result Table"
Or: "Meas Setup" > "Demod" > "Result Table" tab
The demodulation results are displayed in the "Result Summary" table (see also
"Result Summary" on page 22). The detectors used to determine the results can be
configured.
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Demodulation
In addition to common absolute demodulation, the R&S FSW AM/FM/PM Modulation
Analysis application also provides demodulation results relative to user-defined or
measured reference values in the "Result Summary".
The settings for the "Result Summary" can be defined individually for the different modulation types (FM, AM, PM). For each modulation, a separate tab is provided in the dialog box.
Detector.........................................................................................................................84
Mode............................................................................................................................. 84
State..............................................................................................................................84
Reference Value............................................................................................................85
Meas -> Reference........................................................................................................85
Detector
Detector type for demodulation results
"+ Peak"
"- Peak"
"+/- Peak"
"RMS"
Remote command:
The detector is specified by the DETector<det> suffix in
CONFigure:RELative:AM|FM|PM:DETector<det>... commands.
Positive peak
Negative peak
Autopeak
Root mean square
Mode
Defines the mode with which the demodulation result is determined.
The modes are similar to those for the entire trace (see "Trace Mode" on page 97).
"Clear Write"
"Max Hold"
"Average"
Remote command:
CONFigure:ADEMod:RESults:AM:DETector<det>:MODE on page 261
CONFigure:ADEMod:RESults:FM:DETector<det>:MODE on page 261
CONFigure:ADEMod:RESults:PM:DETector<det>:MODE on page 261
State
Activates relative demodulation for the selected detector. If activated, the demodulated
result is set in relation to the Reference Value.
Remote command:
CONFigure:ADEMod:RESults:AM:DETector<det>:STATe on page 259
CONFigure:ADEMod:RESults:FM:DETector<det>:STATe on page 260
CONFigure:ADEMod:RESults:PM:DETector<det>:STATe on page 260
Overwrite mode: the detector value is overwritten by each sweep.
This is the default setting.
The maximum value is determined over several sweeps and displayed. The R&S FSW saves each result only if the new value is
greater than the previous one.
The average result is determined over all sweeps.
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Demodulation
Reference Value
Defines the reference value to be used for relative demodulation results and recalculates the results. If necessary, the detector is activated.
Note: A reference value 0 would provide infinite results and is thus automatically cor-
rected to 0.1.
Remote command:
CONFigure:ADEMod:RESults:AM:DETector<det>:REFerence on page 259
CONFigure:ADEMod:RESults:FM:DETector<det>:REFerence on page 259
CONFigure:ADEMod:RESults:PM:DETector<det>:REFerence on page 259
Meas -> Reference
Sets the Reference Value to be used for relative demodulation results to the currently
measured value for all relative detectors.
Note: A reference value 0 would provide infinite results and is thus automatically cor-
rected to 0.1.
If necessary, the detectors are activated.
Remote command:
CONFigure:ADEMod:RESults:AM:DETector<det>:REFerence:MEAStoref<t>
on page 260
CONFigure:ADEMod:RESults:FM:DETector<det>:REFerence:MEAStoref<t>
on page 260
CONFigure:ADEMod:RESults:PM:DETector<det>:REFerence:MEAStoref<t>
on page 260
5.7.7 Settling time
Access: "Overview" > "Demod Settings" > "Settling Time"
Or: "Meas Setup" > "Demod" > "Settling Time" tab
The settling time defines when the signal remains within a specified target corridor. The
corridor is defined by the upper and lower settling limit. The function is available for all
time domain displays.
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Configuration
Demodulation
If enabled, the time is determined by evaluating the signal values from the end of the
measurement. The last position at which the signal exceeds the corridor is the settling
time. The settling time is defined with reference to the start of the data acquisition or
the trigger event. A possible trigger offset is not considered.
The settling time is indicated by a temporary marker in the time domain diagram. The
result is also indicated in the "result summary". The settling time is evaluated for each
time domain window for the selected trace (see "Selected Trace" on page 69).
State..............................................................................................................................87
Upper Settling Limit.......................................................................................................87
Lower Settling Limit.......................................................................................................87
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Output settings
State
Enables or disables the calculation and display of the settling time.
Remote command:
[SENSe:]ADEMod:SETTling:TIME:STATe on page 262
Result: [SENSe:]ADEMod:SETTling:TIME:RESult<t>? on page 289
Upper Settling Limit
Defines the upper limit of the settling time corridor. The value is defined with reference
to the reference value, see also "Reference Value" on page 79 and "Zero Phase Refer-
ence Position (PM Time Domain only)" on page 71.
Remote command:
[SENSe:]ADEMod:SETTling:TIME:LIMit:UPPer on page 262
Lower Settling Limit
Defines the lower limit of the settling time corridor. The value is defined with reference
to the reference value, see also "Reference Value" on page 79 and "Zero Phase Refer-
ence Position (PM Time Domain only)" on page 71.
Remote command:
[SENSe:]ADEMod:SETTling:TIME:LIMit:LOWer on page 262
5.8 Output settings
● Output settings........................................................................................................87
● Analog demod output settings.................................................................................88
● Digital I/Q 40G output settings................................................................................ 90
5.8.1 Output settings
Access: [Input/Output] > "Output"
The R&S FSW can provide output to special connectors for other devices.
For details on connectors, refer to the R&S FSW Getting Started manual, "Front / Rear
Panel View" chapters.
How to provide trigger signals as output is described in detail in the R&S FSW User
Manual.
Digital I/Q output is not available for Analog Modulation Analysis.
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Output settings
Noise Source Control....................................................................................................88
Noise Source Control
Enables or disables the 28 V voltage supply for an external noise source connected to
the "Noise source control / Power sensor") connector. By switching the supply voltage
for an external noise source on or off in the firmware, you can enable or disable the
device as required.
External noise sources are useful when you are measuring power levels that fall below
the noise floor of the R&S FSW itself, for example when measuring the noise level of
an amplifier.
In this case, you can first connect an external noise source (whose noise power level is
known in advance) to the R&S FSW and measure the total noise power. From this
value, you can determine the noise power of the R&S FSW. Then when you measure
the power level of the actual DUT, you can deduct the known noise level from the total
power to obtain the power level of the DUT.
Remote command:
DIAGnostic:SERVice:NSOurce on page 213
5.8.2 Analog demod output settings
Access: "Overview" ≥ "Output" > "Analog Demod"
The demodulated signal in time domain results can be output to the IF/VIDEO/DEMOD
output connector on the R&S FSW.
Output is not possible if the optional "Digital Baseband" interface is active.
The following settings and functions are available to configure the output in the R&S
FSW AM/FM/PM Modulation Analysis application.
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Output settings
Note that the audio frequency (AF) filter settings used for demodulation also apply to
the online output. However, a maximum of two high pass, low pass or deemphasis filters can be active at the same time if "Analog Demod" output is active.
(See Chapter 5.7.3, "AF filter", on page 74)
Online Demodulation Output State............................................................................... 89
Output Selection............................................................................................................89
AF Coupling.................................................................................................................. 90
AC Cutoff Frequency.....................................................................................................90
Phones Output.............................................................................................................. 90
Online Demodulation Output State
Enables or disables online demodulation output. If enabled, the demodulated audio frequencies are output to the IF/VIDEO/DEMOD output connector on the rear panel of the
R&S FSW.
Optionally, you can output the demodulated signal to the [Phones] connector on the
front panel (see "Phones Output" on page 90).
Remote command:
OUTPut<up>:ADEMod[:ONLine][:STATe] on page 213
SYSTem:SPEaker:VOLume on page 215
Output Selection
Selects the result display whose results are output. Only time domain results can be
selected. All currently active time domain result displays are listed.
"Current Focus" dynamically switches to the currently selected window. Thus you can
easily change the output signal simply by selecting the windows in the display. If a window is selected that does not contain a time-domain result display, the selection is
ignored and the previous setting is maintained.
The result display currently used for output is indicated by a "Demod Out" label in the
window title bar.
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Output settings
Remote command:
OUTPut<up>:ADEMod[:ONLine]:SOURce on page 213
AF Coupling
Controls the automatic correction of the frequency offset and phase offset of the input
signal:
This function is only available for FM or PM time domain evaluations.
●
FM time evaluation
If DC is selected, the absolute frequency is displayed. That means, an input signal
with an offset relative to the center frequency is not displayed symmetrically to the
zero line.
If AC is selected, the frequency offset is automatically corrected, i.e. the trace is
always symmetric to the zero line.
●
PM time evaluation
If DC is selected, the phase runs according to the existing frequency offset. In addition, the DC signal contains a phase offset of ± π.
If AC is selected, the frequency offset and phase offset are automatically corrected,
i.e. the trace is always symmetric to the zero line.
Remote command:
[SENSe:]ADEMod<n>:AF:COUPling on page 244
AC Cutoff Frequency
Defines the cutoff frequency for the AC highpass filter (for AC coupling only, see AF
Coupling).
Note that the audio frequency (AF) filter settings used for demodulation also apply to
the online output.
(See Chapter 5.7.3, "AF filter", on page 74)
Remote command:
OUTPut<up>:ADEMod[:ONLine]:AF[:CFRequency] on page 214
Phones Output
If enabled, the demodulated audio signal is output to the IF/VIDEO/DEMOD connector
(on the rear panel of the R&S FSW), as well as to headphones connected on the front
panel ([Phones] connector), if available.
CAUTION! Risk of hearing damage. Before putting on the headphones, make sure that
the volume setting is not too high to protect your hearing.
Note: If you do not hear output on the connected headphones despite having enabled
both general online demodulation output (see "Online Demodulation Output State"
on page 89) and the speaker, adjust the volume setting using the volume control.
Remote command:
OUTPut<up>:ADEMod[:ONLine]:PHONes on page 214
5.8.3 Digital I/Q 40G output settings
Access: "Overview" > "Output" > "Digital I/Q 40G" tab
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Configuration
Output settings
The optional Digital I/Q 40G Streaming Output interface (R&S FSW-B517/-B1017)
allows you to output I/Q data to an external device at very high sample rates.
These settings are only available if one of the Digital I/Q 40G Streaming Output options
is installed on the R&S FSW.
For details see the R&S FSW I/Q Analyzer and I/Q Input User Manual.
Digital I/Q 40G Streaming Out...................................................................................... 91
Insert Marker.................................................................................................................91
Output Settings Information.......................................................................................... 92
Connected Instrument...................................................................................................92
Digital I/Q 40G Streaming Out
Enables or disables a digital output stream to the optional Digital I/Q 40G Streaming
Output connector, if available.
Remote command:
OUTPut<up>:IQHS[:STATe] on page 216
Insert Marker
Inserts marker information to the data stream during a running I/Q data output recording. Useful to mark a specific event during the measurement that you detect in the
result window, for example. Then you can search for the marker information in the output data to analyze the effects at that time.
Tip: The "I/Q 40G Recording" window also provides an "Insert Marker" 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.
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Configuration
Adjusting settings automatically
For more information, see the R&S FSW I/Q Analyzer and I/Q Input User Manual.
Remote command:
OUTPut<up>:IQHS:MARKer on page 216
Output Settings Information
Displays information on the settings for output via the Digital I/Q 40G Streaming Output
option (R&S FSW-B517/-B1017).
The following information is displayed:
●
Minimum sample rate that can be used to transfer data via the Digital I/Q 40G
Streaming Output interface
●
Maximum sample rate that can be used to transfer data via the Digital I/Q 40G
Streaming Output interface (i.e. the maximum input sample rate that can be processed by the connected instrument)
●
Sample rate currently used to transfer data via the Digital I/Q 40G Streaming Output interface
●
Level and unit that corresponds to an I/Q sample with the magnitude "1" (Full scale
level)
Remote command:
OUTPut<up>:IQHS:SRATe? on page 216
Connected Instrument
Displays information on the instrument connected to the Digital I/Q 40G Streaming
Output connector, if available.
If an instrument is connected, the following information is displayed:
●
Name and serial number of the instrument connected to the QSFP+ connector
●
Used port
Remote command:
OUTPut<up>:IQHS:CDEVice? on page 215
5.9 Adjusting settings automatically
Access: [AUTO SET]
Some settings can be adjusted by the R&S FSW automatically according to the current
measurement settings. To do so, a measurement is performed. You can configure this
measurement.
MSRA/MSRT operating mode
In MSRA and MSRT operating mode, settings related to data acquisition can only be
adjusted automatically for the MSRA/MSRT primary, not the secondary applications.
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Configuration
Adjusting settings automatically
Adjusting settings automatically during triggered measurements
When you select an auto adjust function, a measurement is performed to determine
the optimal settings. If you select an auto adjust function for a triggered measurement,
you are asked how you want the R&S FSW to behave:
●
(default:) The measurement for adjustment waits for the next trigger
●
The measurement for adjustment is performed without waiting for a trigger.
The trigger source is temporarily set to "Free Run". After the measurement is completed, the original trigger source is restored. The trigger level is adjusted as follows:
– For IF Power and RF Power triggers:
Trigger Level = Reference Level - 15 dB
– For Video trigger:
Trigger Level = 85 %
Remote command:
[SENSe:]ADJust:CONFigure:TRIGger on page 266
Adjusting all Determinable Settings Automatically (Auto All)........................................ 93
Adjusting the Center Frequency Automatically (Auto Frequency)................................ 93
AF Auto Scale............................................................................................................... 94
Setting the Reference Level Automatically (Auto Level)...............................................94
Resetting the Automatic Measurement Time (Meastime Auto).....................................94
Changing the Automatic Measurement Time (Meastime Manual)................................ 94
Upper Level Hysteresis.................................................................................................95
Lower Level Hysteresis.................................................................................................95
Adjusting all Determinable Settings Automatically (Auto All)
Activates all automatic adjustment functions for the current measurement settings,
including:
●
Auto Frequency
●
Auto Level
●
"AF Auto Scale" on page 80
Note: MSRA / MSRT operating modes. In MSRA / MSRT operating mode, this function
is only available for the MSRA / MSRT primary, not the secondary applications.
Remote command:
[SENSe:]ADJust:ALL on page 263
Adjusting the Center Frequency Automatically (Auto Frequency)
The R&S FSW adjusts the center frequency automatically.
The optimum center frequency is the frequency with the highest S/N ratio in the fre-
quency span. As this function uses the signal counter, it is intended for use with sinusoidal signals.
This function is not available for input from the optional "Digital Baseband" interface.
Remote command:
[SENSe:]ADJust:FREQuency on page 266
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Configuration
Adjusting settings automatically
AF Auto Scale
Activates automatic scaling of the y-axis for AF measurements. RF power and RF
spectrum measurements are not affected by the auto-scaling.
Remote command:
[SENSe:]ADJust:SCALe[:Y]:AUTO[:CONTinuous] on page 266
Setting the Reference Level Automatically (Auto Level)
Automatically determines a reference level which ensures that no overload occurs at
the R&S FSW for the current input data. At the same time, the internal attenuators and
the preamplifier (for analog baseband input: the full-scale level) are adjusted. As a
result, the signal-to-noise ratio is optimized, while signal compression and clipping are
minimized.
To determine the required reference level, a level measurement is performed on the
R&S FSW.
If necessary, you can optimize the reference level further. Decrease the attenuation
level manually to the lowest possible value before an overload occurs, then decrease
the reference level in the same way.
When using the optional 2 GHz / 5 GHz bandwidth extension (B2000/B5000) or the
optional Oscilloscope Baseband Input, the level measurement is performed on the connected oscilloscope. For B2000/B5000, y-axis scaling on the oscilloscope is limited to
a minimum of 5 mV per division.
You can change the measurement time for the level measurement if necessary (see
"Changing the Automatic Measurement Time (Meastime Manual)" on page 94).
Remote command:
[SENSe:]ADJust:LEVel on page 266
Resetting the Automatic Measurement Time (Meastime Auto)
Resets the measurement duration for automatic settings to the default value.
Remote command:
[SENSe:]ADJust:CONFigure:LEVel:DURation:MODE on page 264
Changing the Automatic Measurement Time (Meastime Manual)
This function allows you to change the measurement duration for automatic setting
adjustments. Enter the value in seconds.
Note: The maximum measurement duration depends on the currently selected measurement and the installed (optional) hardware. Thus, the measurement duration
actually used to determine the automatic settings can be shorter than the value you
define here.
Remote command:
[SENSe:]ADJust:CONFigure:LEVel:DURation:MODE on page 264
[SENSe:]ADJust:CONFigure:LEVel:DURation on page 264
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Configuration
Adjusting settings automatically
Upper Level Hysteresis
When the reference level is adjusted automatically using the Auto Level function, the
internal attenuators and the preamplifier are also adjusted. To avoid frequent adaptation due to small changes in the input signal, you can define a hysteresis. This setting
defines an upper threshold the signal must exceed (compared to the last measurement) before the reference level is adapted automatically.
Remote command:
[SENSe:]ADJust:CONFigure:HYSTeresis:UPPer on page 265
Lower Level Hysteresis
When the reference level is adjusted automatically using the Auto Level function, the
internal attenuators and the preamplifier are also adjusted. To avoid frequent adaptation due to small changes in the input signal, you can define a hysteresis. This setting
defines a lower threshold the signal must fall below (compared to the last measurement) before the reference level is adapted automatically.
Remote command:
[SENSe:]ADJust:CONFigure:HYSTeresis:LOWer on page 265
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Analysis
Trace settings
6 Analysis
Access: "Overview" > "Analysis"
General result analysis settings concerning the trace, markers, lines etc. are identical
to the analysis functions in the base unit except for the special marker functions.
For a description of the lines functionality, see the R&S FSW User Manual.
The remote commands required to perform these tasks are described in Chapter 11,
"Remote commands for AM/FM/PM Modulation Analysis", on page 144.
● Trace settings..........................................................................................................96
● Spectrogram settings............................................................................................ 100
● Trace / data export configuration.......................................................................... 105
● Working with markers in the R&S FSW AM/FM/PM Modulation Analysis application
.............................................................................................................................. 109
● Analysis in MSRA/MSRT mode............................................................................ 133
6.1 Trace settings
Access: "Overview" > "Analysis" > "Traces"
Or: [TRACE] > "Trace Config"
You can configure the settings for up to 6 individual traces in the same result display.
Each trace is displayed in a different color, indicated in the window title bar and the
trace settings.
In the R&S FSW AM/FM/PM Modulation Analysis application, when you configure the
traces for a window with a specific evaluation (e.g. AM time domain), the traces in all
windows with the same evaluation are configured identically.
Trace data can also be exported to an ASCII file for further analysis. For details see
Chapter 6.3, "Trace / data export configuration", on page 105.
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Analysis
Trace settings
Trace 1/Trace 2/Trace 3/Trace 4/Trace 5/Trace 6.........................................................97
Trace Mode...................................................................................................................97
Detector.........................................................................................................................98
Hold...............................................................................................................................98
Average Mode...............................................................................................................98
Average Count.............................................................................................................. 99
Predefined Trace Settings - Quick Config.....................................................................99
Trace 1/ Trace 2/ Trace 3/ Trace 4 (Softkeys)...............................................................99
Trace 1/Trace 2/Trace 3/Trace 4/Trace 5/Trace 6
Selects the corresponding trace for configuration. The currently selected trace is highlighted.
Remote command:
Selected via numeric suffix of:TRACe<1...6> commands
DISPlay[:WINDow<n>][:SUBWindow<w>]:TRACe<t>[:STATe] on page 303
Trace Mode
Defines the update mode for subsequent traces.
"Clear/ Write"
"Max Hold"
"Min Hold"
"Average"
Overwrite mode (default): the trace is overwritten by each sweep.
The maximum value is determined over several sweeps and dis-
played. The R&S FSW saves each trace point in the trace memory
only if the new value is greater than the previous one.
The minimum value is determined from several measurements and
displayed. The R&S FSW saves each trace point in the trace memory
only if the new value is lower than the previous one.
The average is formed over several sweeps.
The Sweep/Average Count determines the number of averaging procedures.
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Analysis
Trace settings
"View"
"Blank"
Remote command:
DISPlay[:WINDow<n>][:SUBWindow<w>]:TRACe<t>:MODE on page 301
Detector
Defines the trace detector to be used for trace analysis.
"Auto"
"Type"
Remote command:
[SENSe:][WINDow<n>:]DETector<t>[:FUNCtion] on page 307
[SENSe:][WINDow<n>:]DETector<t>[:FUNCtion]:AUTO on page 307
The current contents of the trace memory are frozen and displayed.
Removes the selected trace from the display.
(default:) Selects the optimum detector for the selected trace and filter mode
Defines the selected detector type.
Note: If the EMI (R&S FSW-K54) measurement option is installed,
additional detectors are available, even if EMI measurement is not
active. If you select a CISPR trace detector, the RBW filter type is
automatically also set to CISPR.
CISPR detectors are not available for the following measurements:
●
Frequency sweep measurements in FFT mode
●
Emission measurements
●
Power measurements
●
Statistics measurements
Hold
If activated, traces in "Min Hold", "Max Hold" and "Average" mode are not reset after
specific parameter changes have been made.
Normally, the measurement is started again after parameter changes, before the measurement results are analyzed (e.g. using a marker). In all cases that require a new
measurement after parameter changes, the trace is reset automatically to avoid false
results (e.g. with span changes). For applications that require no reset after parameter
changes, the automatic reset can be switched off.
The default setting is off.
Remote command:
DISPlay[:WINDow<n>][:SUBWindow<w>]:TRACe<t>:MODE:HCONtinuous
on page 302
Average Mode
Defines the mode with which the trace is averaged over several sweeps.
This setting is generally applicable if trace mode "Average" is selected.
For FFT sweeps, the setting also affects the VBW (regardless of whether the trace is
averaged).
(See the chapter on ACLR power measurements in the R&S FSW User Manual.)
How many sweeps are averaged is defined by the "Average Count" on page 99.
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Analysis
Trace settings
"Linear"
The power level values are converted into linear units before averaging. After the averaging, the data is converted back into its original
unit.
"Logarithmic"
For logarithmic scaling, the values are averaged in dBm. For linear
scaling, the behavior is the same as with linear averaging.
"Power"
Activates linear power averaging.
The power level values are converted into unit Watt before averaging.
After the averaging, the data is converted back into its original unit.
Use this mode to average power values in Volts or Amperes correctly.
In particular, for small VBW values (smaller than the RBW), use
power averaging mode for correct power measurements in FFT
sweep mode.
Remote command:
[SENSe:]AVERage<n>:TYPE on page 306
Average Count
Determines the number of averaging or maximum search procedures If the trace
modes "Average", "Max Hold" or "Min Hold" are set.
In continuous sweep mode, if sweep count = 0 (default), averaging is performed over
10 sweeps. For sweep count =1, no averaging, Max Hold or Min Hold operations are
performed.
Remote command:
[SENSe:]AVERage<n>:COUNt on page 305
Predefined Trace Settings - Quick Config
Commonly required trace settings have been predefined and can be applied very
quickly by selecting the appropriate button.
Function Trace Settings
Preset All Traces Trace 1: Clear Write
Traces 2-6: Blank
Set Trace Mode
Max | Avg | Min
Set Trace Mode
Max | ClrWrite | Min
Trace 1: Max Hold
Trace 2: Average
Trace 3: Min Hold
Traces 4-6: Blank
Trace 1: Max Hold
Trace 2: Clear Write
Trace 3: Min Hold
Traces 4-6: Blank
Trace 1/ Trace 2/ Trace 3/ Trace 4 (Softkeys)
Displays the "Traces" settings and focuses the "Mode" list for the selected trace.
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6.2 Spectrogram settings
Analysis
Spectrogram settings
Remote command:
DISPlay[:WINDow<n>][:SUBWindow<w>]:TRACe<t>[:STATe] on page 303
Access: [TRACE] > "Spectrogram Config"
The individual settings available for spectrogram display are described here. For settings on color mapping, see Chapter 6.2.2, "Color map settings", on page 104.
Settings concerning the frames and how they are handled during a sweep are provided
as additional sweep settings for spectrogram display.
See Chapter 5.5, "Data acquisition", on page 62.
Search functions for spectrogram markers are described in Chapter 6.4.3, "Marker
search settings for spectrograms", on page 117.
● General spectrogram settings...............................................................................100
● Color map settings................................................................................................ 104
6.2.1 General spectrogram settings
Access: [TRACE] > "Spectrogram Config"
This section describes general settings for spectrogram display.
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