R&S®FSW-K50
Spurious Measurement
User Manual
(;ÜKÀ2)
1178275002
Version 14
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-K50 (1325.2893.02)
© 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.
1178.2750.02 | Version 14 | R&S®FSW-K50
The following abbreviations are used throughout this manual: R&S®FSW is abbreviated as R&S FSW.
R&S®FSW-K50
1 Preface.................................................................................................... 9
1.1 Documentation overview..............................................................................................9
1.1.1 Getting started manual....................................................................................................9
1.1.2 User manuals and help................................................................................................... 9
1.1.3 Service manual............................................................................................................. 10
1.1.4 Instrument security procedures.....................................................................................10
1.1.5 Printed safety instructions............................................................................................. 10
1.1.6 Data sheets and brochures........................................................................................... 10
1.1.7 Release notes and open-source acknowledgment (OSA)............................................ 10
1.1.8 Application notes, application cards, white papers, etc.................................................10
1.2 About this manual....................................................................................................... 11
Contents
Contents
1.3 Conventions used in the documentation..................................................................12
1.3.1 Typographical conventions............................................................................................12
1.3.2 Conventions for procedure descriptions........................................................................12
1.3.3 Notes on screenshots................................................................................................... 12
2 Welcome to the R&S FSW Spurious measurements application.... 13
2.1 Starting the R&S FSW Spurious measurements application..................................13
2.2 Understanding the display information.................................................................... 14
3 Measurement basics............................................................................17
3.1 Spurious emissions.................................................................................................... 17
3.2 Frequency plan and spur identification.................................................................... 17
3.3 Measurement process................................................................................................ 18
4 Measurement types and results......................................................... 20
4.1 Evaluation methods.................................................................................................... 20
5 Configuration........................................................................................25
5.1 Configuration overview.............................................................................................. 25
5.2 Input settings...............................................................................................................27
5.2.1 Input source settings..................................................................................................... 27
5.2.1.1 Radio frequency input................................................................................................... 28
5.2.2 LISN control settings..................................................................................................... 31
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5.3 Trigger settings........................................................................................................... 33
5.4 Measurement settings................................................................................................ 38
5.5 Carrier reference settings.......................................................................................... 41
5.6 Wide Search Measurement settings..........................................................................44
5.6.1 Managing ranges.......................................................................................................... 45
5.6.2 Configuring individual ranges........................................................................................46
5.7 Identification settings - DUT frequency plan............................................................50
5.8 Transferring settings between measurements.........................................................54
5.8.1 Segment table............................................................................................................... 54
5.8.2 Spur table......................................................................................................................55
5.9 Directed Search Measurement settings....................................................................56
5.9.1 Managing spans............................................................................................................56
5.9.2 Configuring spur search spans..................................................................................... 61
Contents
5.10 Display configuration................................................................................................. 63
5.11 Result configuration................................................................................................... 63
5.11.1 Spurious detection table configuration.......................................................................... 63
5.11.2 Results settings.............................................................................................................64
5.12 Sweep settings............................................................................................................ 66
5.13 Adjusting settings automatically...............................................................................67
6 Analysis................................................................................................ 68
6.1 Y-Scaling......................................................................................................................68
6.2 Trace settings..............................................................................................................70
6.3 Trace / table export configuration............................................................................. 70
6.4 Markers........................................................................................................................ 72
6.4.1 Individual marker settings............................................................................................. 72
6.4.2 General marker settings................................................................................................76
6.4.3 Marker search settings and positioning functions......................................................... 77
6.4.3.1 Marker search settings..................................................................................................77
6.4.3.2 Positioning functions..................................................................................................... 78
6.5 Display line settings................................................................................................... 80
7 How to perform Spurious measurements..........................................81
7.1 How to perform a Wide Search Measurement..........................................................81
7.2 How to perform a Directed Search Measurement.................................................... 82
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7.3 How to perform a combined Wide Search Measurement and Directed Search
7.4 How to perform a spurious search measurement with a DUT frequency plan..... 84
8 Remote commands to perform Spurious measurements................ 86
8.1 Introduction................................................................................................................. 87
8.1.1 Conventions used in descriptions................................................................................. 87
8.1.2 Long and short form...................................................................................................... 88
8.1.3 Numeric suffixes............................................................................................................88
8.1.4 Optional keywords.........................................................................................................89
8.1.5 Alternative keywords..................................................................................................... 89
8.1.6 SCPI parameters...........................................................................................................89
8.1.6.1 Numeric values............................................................................................................. 90
8.1.6.2 Boolean......................................................................................................................... 90
Contents
Measurement............................................................................................................... 83
8.1.6.3 Character data.............................................................................................................. 91
8.1.6.4 Character strings...........................................................................................................91
8.1.6.5 Block data..................................................................................................................... 91
8.2 Activating Spurious measurements..........................................................................92
8.3 Configuring Spurious measurements.......................................................................95
8.3.1 Configuring the data input............................................................................................. 96
8.3.1.1 RF input.........................................................................................................................96
8.3.1.2 Working with power sensors....................................................................................... 100
Configuring power sensors......................................................................................... 100
Configuring power sensor measurements.................................................................. 102
Triggering with power sensors.................................................................................... 108
8.3.1.3 Using external mixers..................................................................................................110
Basic settings.............................................................................................................. 110
Mixer settings.............................................................................................................. 112
Conversion loss table settings.....................................................................................118
Programming example: working with an external mixer..............................................122
8.3.1.4 Configuring LISN input................................................................................................ 124
8.3.2 Configuring triggered measurements..........................................................................126
8.3.2.1 Configuring the triggering conditions...........................................................................126
8.3.2.2 Configuring the trigger output......................................................................................129
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8.3.3 Measurement control commands................................................................................132
8.3.4 Carrier reference level commands.............................................................................. 134
8.3.5 Wide Search Measurement settings commands.........................................................138
8.3.6 Frequency plan identification commands....................................................................145
8.3.7 Directed Search Measurement settings commands................................................... 149
8.3.8 Transferring settings between measurements............................................................ 154
8.3.9 Configuring the result displays.................................................................................... 155
8.3.9.1 General window commands........................................................................................155
8.3.9.2 Working with windows in the display...........................................................................156
8.3.9.3 Configuring tables and diagrams................................................................................ 162
8.4 Performing measurements.......................................................................................163
8.5 Analyzing Spurious measurements........................................................................ 165
8.5.1 Configuring the Y-Axis scaling.....................................................................................165
Contents
8.5.2 Setting up individual markers...................................................................................... 167
8.5.3 General marker settings..............................................................................................174
8.5.4 Configuring and performing a marker search..............................................................175
8.5.5 Positioning the marker................................................................................................ 178
8.5.5.1 Positioning normal markers.........................................................................................178
8.5.5.2 Positioning delta markers............................................................................................180
8.5.6 Configuring traces....................................................................................................... 182
8.5.7 Configuring display lines............................................................................................. 183
8.6 Retrieving results......................................................................................................185
8.6.1 Retrieving and storing trace data................................................................................ 186
8.6.2 Checking the results of a limit check...........................................................................187
8.6.3 Exporting table and trace results to an ASCII file........................................................188
8.6.4 Retrieving marker results............................................................................................ 191
8.7 Status reporting system........................................................................................... 193
8.8 Programming examples: spurious emissions measurements............................. 193
8.8.1 Performing a wide search measurement.................................................................... 193
8.8.2 Performing a directed search measurement............................................................... 196
8.8.3 Performing a spurious search measurement using a frequency plan......................... 197
Annex.................................................................................................. 200
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A Reference: ASCII file export format..................................................200
Contents
List of Commands (Spurious)...........................................................202
Index....................................................................................................208
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Contents
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1 Preface
1.1 Documentation overview
1.1.1 Getting started manual
Preface
Documentation overview
This chapter provides safety-related information, an overview of the user documentation and the conventions used in the documentation.
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.
1.1.2 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.
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1.1.3 Service manual
1.1.4 Instrument security procedures
1.1.5 Printed safety instructions
Preface
Documentation overview
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):
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.
1.1.6 Data sheets and brochures
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
1.1.7 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
1.1.8 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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1.2 About this manual
Preface
About this manual
This Spurious Measurements User Manual provides all the information specific to the
application. All general instrument functions and settings common to all applications
and operating modes are described in the main R&S FSW User Manual.
The main focus in this manual is on the measurement results and the tasks required to
obtain them. The following topics are included:
●
Welcome to the R&S FSW Spurious measurements application
Introduction to and getting familiar with the application
●
About the measurement
General concept of the Spurious measurement and typical applications
●
Measurements and Result Displays
Details on supported measurements and their result types
●
Measurement Basics
Background information on basic terms and principles in the context of the measurement
●
Configuration + Analysis
A concise description of all functions and settings available to configure measurements and analyze results with their corresponding remote control command
●
How to Perform Measurements in the R&S FSW Spurious measurements
application
Step-by-step instructions to perform a basic Spurious measurement
●
Measurement Examples
Detailed measurement examples to guide you through typical measurement scenarios and allow you to try out the application immediately
●
Optimizing and Troubleshooting the Measurement
Hints and tips on how to handle errors and optimize the test setup
●
Remote Commands for Spurious Measurements
Remote commands required to configure and perform Spurious measurements in a
remote environment, sorted by tasks
(Commands required to set up the environment or to perform common tasks on the
instrument are provided in the main R&S FSW User Manual)
Programming examples demonstrate the use of many commands and can usually
be executed directly for test purposes
●
Annex
Reference material
●
List of remote commands
Alphabetical list of all remote commands described in the manual
●
Index
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1.3 Conventions used in the documentation
1.3.1 Typographical conventions
Preface
Conventions used in the documentation
The following text markers are used throughout this documentation:
Convention Description
"Graphical user interface elements"
[Keys] Key and knob names are enclosed by square brackets.
Filenames, commands,
program code
Input Input to be entered by the user is displayed in italics.
Links Links that you can click are displayed in blue font.
"References" References to other parts of the documentation are enclosed by quota-
All names of graphical user interface elements on the screen, such as
dialog boxes, menus, options, buttons, and softkeys are enclosed by
quotation marks.
Filenames, commands, coding samples and screen output are distinguished by their font.
tion marks.
1.3.2 Conventions for procedure descriptions
When operating the instrument, several alternative methods may be available to perform the same task. In this case, the procedure using the touchscreen is described.
Any elements that can be activated by touching can also be clicked using an additionally connected mouse. The alternative procedure using the keys on the instrument or
the on-screen keyboard is only described if it deviates from the standard operating procedures.
The term "select" may refer to any of the described methods, i.e. using a finger on the
touchscreen, a mouse pointer in the display, or a key on the instrument or on a keyboard.
1.3.3 Notes on screenshots
When describing the functions of the product, we use sample screenshots. These
screenshots are meant to illustrate as many as possible of the provided functions and
possible interdependencies between parameters. The shown values may not represent
realistic usage scenarios.
The screenshots usually show a fully equipped product, that is: with all options installed. Thus, some functions shown in the screenshots may not be available in your particular product configuration.
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Welcome to the R&S FSW Spurious measurements application
Starting the R&S
FSW Spurious measurements application
2 Welcome to the R&S FSW Spurious mea-
surements application
The R&S FSW-K50 is a firmware application that allows you to perform Spurious measurements on the R&S FSW very quickly and easily.
As an addition to the basic Spurious measurements available in the R&S FSW base
unit, the R&S FSW Spurious measurements application features:
●
Very quick spurious measurements on predefined measurement ranges using optimized RBWs
●
Simple configuration of spurious measurements
●
Storage of user-defined measurement configurations
●
Measurement of both the power and the frequency of detected spurs
●
Analysis methods to determine spurs generated internally by the spectrum analyzer itself, and to eliminate these effects
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.
Installation
You can find detailed installation instructions in the "R&S FSW Getting Started" manual
or in the release notes.
2.1 Starting the R&S FSW Spurious measurements appli-
cation
The R&S FSW Spurious measurements application adds a new application to the
R&S FSW.
To activate the R&S FSW Spurious measurements application
1. Press the [MODE] key on the front panel of the R&S FSW.
A dialog box opens that contains all operating modes and applications currently
available on your R&S FSW.
2. Select the "Fast Spur Search" item.
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Welcome to the R&S FSW Spurious measurements application
Understanding the display information
The R&S FSW opens a new measurement channel for the R&S FSW Spurious
measurements application.
The measurement is started immediately with the default settings. It can be configured
in the Spurious "Overview" dialog box, which is displayed when you select the "Overview" softkey from any menu (see Chapter 5.1, "Configuration overview",
on page 25).
Multiple Measurement Channels and Sequencer Function
When you activate an application, a new measurement channel is created which determines the measurement settings for that application. The same application can be activated with different measurement settings by creating several channels for the same
application.
The number of channels that can be configured at the same time depends on the available memory on the instrument.
Only one measurement can be performed at any time, namely the one in the currently
active channel. However, a Sequencer function is provided that allows you to perform
the configured measurements consecutively.
If activated, the measurements configured in the currently active channels are performed one after the other in the order of the tabs. The currently active measurement is
indicated by a
are updated in the tabs (including 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. The result displays of the individual channels
2.2 Understanding the display information
The following figure shows a measurement diagram during analyzer operation. 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 Spurious measurements application
Understanding the display information
1
6
5
1 = Channel bar for firmware and measurement settings
2+3 = Window title bar with diagram-specific (trace) information
4 = Diagram area with spur detection threshold and limit offset lines
5 = Diagram footer with diagram-specific information, depending on measurement application
6 = Instrument status bar with error messages, progress bar and date/time display
4
Channel bar information
In the R&S FSW Spurious measurements application, the R&S FSW shows the following settings:
2
3
Table 2-1: Information displayed in the channel bar in the R&S
tion
"Ref Level" Reference level
"Spur Search" Measurement type ("Wide", "Direct")
"RBW" Currently used RBW during measurement
"Freq" Currently processed center frequency during measurement
"SGL" The measurement is set to single mode
"Meas Time" A minimum estimate for the required measurement time; available after
Spectral Overview is finished
Note that the estimate includes a spurious detection sweep and spot
search, assuming 10 spur candidates are found in the spurious detection
sweep. If the signal to be measured does not meet the assumptions, the
estimated measurement time may be too low.
FSW Spurious measurements applica-
The channel bar also displays information on instrument settings that affect the measurement results even though this is not immediately apparent from the display of the
measured values (e.g. transducer or trigger settings). This information is displayed only
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Welcome to the R&S FSW Spurious measurements application
Understanding the display information
when applicable for the current measurement. For details, see the R&S FSW Getting
Started manual.
Window title bar information
For each diagram, the header provides the following information:
1 2 3 4 5
Figure 2-1: Window title bar information in the R&S FSW Spurious measurements application
1 = Window number
2 = Window type
3 = Trace color
4 = Trace number
5 = Trace mode
Diagram footer information
The diagram footer (beneath the diagram) contains the following information:
●
Start and stop frequency
●
Number of trace points
●
Range per division (x-axis)
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 measurement is displayed in the status bar. For details on the measurement process, see
Chapter 3.3, "Measurement process", on page 18.
Depending on the currently running measurement (step), the following information is
indicated in the status bar:
●
Which measurement step is being performed
●
The total number of segments required to meet the user specification and the segment currently being processed
●
The total number of data acquisitions required to meet the user specification and
the acquisition currently being processed
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3 Measurement basics
3.1 Spurious emissions
Measurement basics
Frequency plan and spur identification
Some background knowledge on basic terms and principles used in Spurious measurements is provided here for a better understanding of the required configuration settings.
● Spurious emissions.................................................................................................17
● Frequency plan and spur identification................................................................... 17
● Measurement process.............................................................................................18
Spurious emissions can be generated by a variety of processes, including:
●
Instability, parasitic oscillations and resonances
●
Harmonics
●
Interference: RF leakage, EMI ingress from digital clocks
●
Modulation: Intermodulation (IM) and cross-modulation (CM) effects
●
Spurs internally generated by the test equipment (spectrum analyzer)
These spurious emissions can cause problems for the equipment manufacturer including:
●
Interference with radio transmissions in adjacent bands
●
Interference with other modules contained within the equipment
●
Violation of regulatory limits
●
Power inefficiencies due to the transmissions of non-usable frequencies
Thus, the R&S FSW Spurious measurements application allows you to detect, measure and identify spurious signals, based on common spectrum analyzer functionality.
Residuals
Residuals are spurs that are created by the analyzer itself. These spurs are identified
by the R&S FSW Spurious measurements application automatically, and can be displayed or removed from the measured results.
3.2 Frequency plan and spur identification
You can define the main components in the signal chain of your DUT with the corresponding frequencies in a frequency plan. Then the R&S FSW Spurious measurements application can calculate the frequencies for possible spurs at those frequencies
and the frequencies of mixer products up to a maximum number of harmonics. After a
measurement, the R&S FSW Spurious measurements application compares the detected spurious results to the predicted frequencies. Spurs that occur at one of the predicted frequencies are identified. Thus, you get an idea of the possible source of the
spurs.
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3.3 Measurement process
Measurement basics
Measurement process
Note that if several combinations of components, input frequencies and harmonics lead
to the same predicted spur frequency, the spur identification with the lowest harmonic
is indicated. If the frequency is still not unique, the identification with the shortest string
length is indicated.
If you transfer the predicted frequencies from a frequency plan to a directed search
measurement, the measurement is only performed at the frequencies specified in the
plan.
For details on how to perform a measurement using a frequency plan, see Chapter 7.4,
"How to perform a spurious search measurement with a DUT frequency plan",
on page 84.
The R&S FSW Spurious measurements application provides two different measurement types (see also Chapter 4, "Measurement types and results", on page 20):
●
A measurement on a wide frequency range (wide search measurement), intended
for unknown spurious scenarios.
●
A detailed measurement (directed search measurement) at specific frequencies
with a small span around each frequency.
Although the two measurement types use different measurement settings, the individual measurement steps are the same for both types.
The basic measurement process consists of the following steps:
1. Spectral overview: An initial sweep from the beginning of the first defined range to
the end of the last defined range (for directed search measurement: from the first
to the last span), using a large RBW and short sweep time to obtain an overview of
the input signal quickly.
The spectral overview allows the R&S FSW Spurious measurements application to
estimate the noise floor for the current user settings for the complete frequency
span defined by the ranges or directed search measurements.
Note: If the signal contains a guard interval, you can restrict the spur search to
ignore a certain span around the carrier. In this case, the spectral overview contains gaps at the specified spans.
2. Noise floor estimation: Estimation of the noise floor from the beginning of the first
defined range to the end of the last defined range (for directed search measurement: from the first to the last span), determined from the spectral overview sweep.
The noise floor estimate is required to set the RBW optimally for subsequent measurement steps: Due to noise variations across the frequencies, the RBW required
to achieve the user-defined spur detection threshold varies. Each range is thus
split into smaller segments that use a constant RBW setting for the complete segment span. The frequency span of the segments depends on the signal and noise
conditions and on the settings. As a result, a segment table is created. This table
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Measurement basics
Measurement process
can be analyzed and used for repeated measurements with the same settings (see
Chapter 5.8, "Transferring settings between measurements", on page 54).
3. Spurious detection: A second sweep performed in the predefined ranges/
segments/spans according to the wide search measurement/directed search measurement configuration. The RBW determined by the noise floor estimate or, for
manual RBW configuration, the user-defined RBW is used. Depending on the size
of the range/span and the required RBW, multiple data acquisitions (or more precisely: FFTs) may be required.
Within the defined and swept ranges/spans, the noise floor is displayed below the
user-defined spur detection threshold. Outside the ranges/spans, no trace is available.
Measured power values that exceed the detection threshold are possible spurs and
are entered in the "Spurious Detection Table".
4. Spot Search: A final sweep on each of the possible spurs in the "Spurious Detection Table" to determine whether the peak is a real spur, an artifact of noise, or generated internally. The RBW for these spot searches may be reduced further compared to the spurious detection sweep: It is set such that the final spur has at least
the user-defined minimum SNR (see "Minimum Spur SNR" on page 62).
The lower RBW leads to a lower noise floor for this scan region compared to the
surrounding regions. Thus, a message indicating the possibility of lower noise
floors is displayed during the spot search (see "Show Messages" on page 65).
Spurs that are found to be artifacts of noise or residuals during the spot search are
removed from the "Spurious Detection Table". (Alternatively, residuals can be
marked instead of removed).
After the spot search, the "Spurious Detection Table" contains all peaks that still
exceed the detection threshold, and are considered a spur. All spurs that exceed
the limit line are marked red (see "Limit Offset to Detection Threshold"
on page 58). The spur frequency and level are updated with more accurate values during the spot search.
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4 Measurement types and results
Measurement types and results
Evaluation methods
Access: "Overview" > "Measurement Control"
Or: [MEAS CONFIG] > "Measurement Control"
There are two different Spurious measurement types for common measurement scenarios, which require different settings.
Wide Search Measurement
A wide search measurement is a measurement with a large span to detect any possible spurs in the entire frequency span of an input signal. This measurement is useful if
you have little or no knowledge of the current input signal or where to expect spurs,
and require an overview.
Directed Search Measurement
A directed search measurement is a measurement performed at predefined discrete
frequencies with settings optimized for the current signal and noise levels at those frequencies. This measurement is targeted at determining the precise level and exact frequency of spurs that are basically known or expected.
The results of both measurements on the same signal are basically the same; however, the directed search measurement can save measurement time if the frequencies
for possible spurs are known in advance. Furthermore, the directed search measurement can provide more precise results, using a larger SNR for a smaller span.
Combined Wide Search Measurement and Directed Search Measurement
Both types of measurement can be combined, if only some of the spurs found during
the wide search measurement are to be analyzed further:
1. Perform a wide search measurement to obtain an overview and detect the spurs in
a large frequency span.
2. Transfer the frequencies of interest to the directed search measurement configuration.
3. Perform a directed search measurement at the frequencies of interest only in a
second measurement.
4.1 Evaluation methods
Access: "Overview" > "Display Config"
Or: [MEAS]
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Measurement types and results
Evaluation methods
The data that was measured by the R&S FSW Spurious measurements application
can be evaluated using various different methods. All evaluation methods available for
the Spurious measurements are displayed in the selection bar in SmartGrid mode.
For details on working with the SmartGrid, see the R&S FSW Getting Started manual.
By default, the following result displays are provided for Spurious measurements:
●
"Spectral Overview" on page 21
●
"Spurious Detection Spectrum" on page 22
●
"Spurious Detection Table" on page 23
Spectral Overview.........................................................................................................21
Spurious Detection Spectrum....................................................................................... 22
Spurious Detection Table.............................................................................................. 23
Noise Floor Estimate.....................................................................................................24
Marker Table................................................................................................................. 24
Spectral Overview
Displays a spectrum diagram of the "Spectral Overview" (see Chapter 3.3, "Measure-
ment process", on page 18), meant to obtain an overview of the input signal and the
required measurement settings. A continuous trace is shown for the entire measurement span.
The specified detection threshold for each range/span is indicated by a blue line in the
diagram (only if it is within the displayed power region, see "Detection Threshold"
on page 62).
Note: If the signal contains a guard interval, you can restrict the spur search to ignore
a certain span around the carrier. In this case, the spectral overview contains gaps at
the specified spans.
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Measurement types and results
Evaluation methods
Remote command:
LAY:ADD? '1',RIGH,SOVerview, see LAYout:ADD[:WINDow]? on page 156
Storing results:
MMEMory:STORe<n>:TRACe on page 191
Spurious Detection Spectrum
Displays the results of the spurious detection sweep (see Chapter 3.3, "Measurement
process", on page 18) as a spectrum diagram for the (discrete) swept ranges. For
ranges that include gaps and for directed search measurements, the diagram shows
several separate trace parts, one for each measured frequency range or span.
The specified detection threshold for each range/span is indicated by a blue line in the
diagram (see "Detection Threshold" on page 62).
The limit line defined as an offset to the detection threshold is indicated by a red line in
the diagram (see "Limit Offset to Detection Threshold" on page 58).
Colored bars beneath the diagram indicate the specified measurement ranges (see
Chapter 3.3, "Measurement process", on page 18).
(Both lines and the colored bars can be hidden, see Chapter 5.11.2, "Results settings",
on page 64.)
The result of the overall limit check for the entire measurement is indicated at the top of
the diagram. If any spurs exceed the defined limit line for the corresponding range or
span, the limit check is failed.
Remote command:
LAY:ADD? '1',RIGH,SDETection, see LAYout:ADD[:WINDow]? on page 156
Storing results:
MMEMory:STORe<n>:TRACe on page 191
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Measurement types and results
Evaluation methods
Spurious Detection Table
Displays the numerical results of the detected spurs. Optionally, residual spurs are indicated in light gray (see "Mark Residual Spurs" on page 40). Spurs that exceed the
defined limit are indicated in red (see "Limit Offset to Detection Threshold"
on page 58).
During the measurement process (see Chapter 3.3, "Measurement process",
on page 18), the values are updated and refined. The spurs are listed in the order they
are detected, that is: in ascending order of frequency. Each spur ID is indicated in the
same color as the range it was found in (see also "Spurious Detection Spectrum"
on page 22).
If identification according to the DUT's frequency plan is activated and possible, the
detected spurs' identification is also displayed. Note that if several combinations of
components, input frequencies and harmonics lead to the same predicted spur frequency, the spur identification with the lowest harmonic is indicated. If the frequency is
still not unique, the identification with the shortest value is indicated.
Note: You can configure which results to display in the table in order to use the available display space optimally or reduce the time to store the results (see Chapter 5.11.1,
"Spurious detection table configuration", on page 63).
Table 4-1: Spurious Detection Table Results
Column Description
"Frequency" The frequency of the spur
"Power" The power level measured at the spur
"Delta to Limit" The difference between the measured power and the defined limit value
"RBW" The RBW that was used in that range
"Segment
Start" / "Segment Stop"
"Spur ID" Consecutive number of spur in the order it was found; indicated in same color as the
"Identification" Identified spur from the frequency plan, if available
The start and stop frequency of the segment in which the spur was found;
(For measurements without optimization, the values correspond to the range frequen-
cies.)
range it was found in
Remote command:
LAY:ADD? '1',RIGH,SDTable, see LAYout:ADD[:WINDow]? on page 156
Storing results:
MMEMory:STORe<n>:TABLe on page 190
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Measurement types and results
Evaluation methods
Noise Floor Estimate
Displays the noise floor estimated during the "Spectral Overview". This information
helps you understand the RBWs used for the individual segments by the R&S FSW
Spurious measurements application.
Remote command:
LAY:ADD? '1',RIGH,NESTimate, see LAYout:ADD[:WINDow]? on page 156
Storing results:
MMEMory:STORe<n>:TRACe on page 191
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 76).
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 156
Results:
CALCulate<n>:MARKer<m>:X on page 173
CALCulate<n>:MARKer<m>:Y? on page 192
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5 Configuration
Configuration
Configuration overview
Access: [MODE] > "Spurious"
Spurious measurements require a special application on the R&S FSW.
When you switch a measurement channel to the R&S FSW Spurious measurements
application the first time, a set of parameters is passed on from the currently active
application. After initial setup, the parameters for the measurement channel are stored
upon exiting and restored upon re-entering the channel. Thus, you can switch between
applications quickly and easily.
When you activate a measurement channel in the R&S FSW Spurious measurements
application, the "Spurious" menu is displayed and provides access to the most important configuration functions.
● Configuration overview............................................................................................25
● Input settings...........................................................................................................27
● Trigger settings....................................................................................................... 33
● Measurement settings.............................................................................................38
● Carrier reference settings........................................................................................41
● Wide Search Measurement settings....................................................................... 44
● Identification settings - DUT frequency plan........................................................... 50
● Transferring settings between measurements........................................................54
● Directed Search Measurement settings..................................................................56
● Display configuration...............................................................................................63
● Result configuration................................................................................................ 63
● Sweep settings........................................................................................................66
● Adjusting settings automatically..............................................................................67
5.1 Configuration overview
Access: all menus
Throughout the measurement channel configuration, an overview of the most important
currently defined settings is provided in the "Overview".
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Configuration
Configuration 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. Thus, you can easily configure an entire measurement channel
from input over processing to output by stepping through the dialog boxes as indicated
in the "Overview".
Depending on the measurement currently selected in the Measurement settings settings, the required steps in the overview differ slightly.
In particular, the "Overview" provides quick access to the following configuration dialog
boxes:
1. Input/ Output/Trigger
See Chapter 5.2, "Input settings", on page 27
2. Carrier Reference Settings
See Chapter 5.5, "Carrier reference settings", on page 41
3. Measurement Settings
See Chapter 5.4, "Measurement settings", on page 38
4. Wide Search Settings
See Chapter 5.6, "Wide Search Measurement settings", on page 44
5. Frequency Plan
See Chapter 5.7, "Identification settings - DUT frequency plan", on page 50
6. Transfer
See Chapter 5.8.2, "Spur table", on page 55/ Chapter 5.8.1, "Segment table",
on page 54
7. Directed Search Settings
See Chapter 5.9, "Directed Search Measurement settings", on page 56
8. Display Configuration
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Configuration
Input settings
See Chapter 5.10, "Display configuration", on page 63
To configure settings
► Select any button to open the corresponding dialog box. To configure a particular
setting displayed in the "Overview", simply select the setting on the touch screen.
The corresponding dialog box is opened with the focus on the selected setting.
For step-by-step instructions on configuring Spurious measurements, see Chapter 7,
"How to perform Spurious measurements", on page 81.
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 95
5.2 Input settings
Access: "Overview" > "Input/Output/Trigger"
The R&S FSW can evaluate signals from different input sources and provide various
types of output (such as noise or trigger signals).
External mixers and power sensors are supported by the R&S FSW Spurious measurements application, but not described here. See the R&S FSW User Manual for
details.
● Input source settings...............................................................................................27
● LISN control settings...............................................................................................31
5.2.1 Input source settings
Access: "Overview" > "Input/Output/Trigger" > "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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5.2.1.1 Radio frequency input
Configuration
Input settings
Further input sources
The R&S FSW Spurious measurements application application can also process input
from the following optional sources:
●
External mixer
●
Probes
●
Power sensors
For details, see the R&S FSW I/Q Analyzer and I/Q Input User Manual.
● Radio frequency input............................................................................................. 28
Access: "Overview" > "Input/Frontend" > "Input Source" > "Radio Frequency"
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................................................................................................. 29
Input Coupling...............................................................................................................29
Impedance.................................................................................................................... 29
Direct Path.................................................................................................................... 30
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Configuration
Input settings
High Pass Filter 1 to 3 GHz...........................................................................................30
YIG-Preselector.............................................................................................................30
Input Connector.............................................................................................................30
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"
1.00 mm RF input connector for frequencies up to 85 GHz (90 GHz
with option R&S FSW-B90G)
"Input 2"
Remote command:
INPut<ip>:SELect on page 99
INPut<ip>:TYPE on page 99
Input Coupling
The RF input of the R&S FSW can be coupled by alternating current (AC) or direct current (DC).
For an active external frontend, input coupling is always DC.
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 97
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.
1.85 mm RF input connector for frequencies up to 67 GHz
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).
Remote command:
INPut<ip>:IMPedance on page 99
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Configuration
Input settings
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.
For an active external frontend, the direct path is always used automatically for frequencies close to zero.
"Auto"
"Off"
Remote command:
INPut<ip>:DPATh on page 97
(Default) The direct path is used automatically for frequencies close
to zero.
The analog mixer path is always used.
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.
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 98
YIG-Preselector
Enables or disables the YIG-preselector, if available on the R&S FSW.
The R&S FSW Spurious measurements application requires the YIG-preselector at the
input of the R&S FSW to ensure that image frequencies are rejected. However, image
rejection is only possible for a restricted bandwidth.
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 98
Input Connector
Determines which connector the input data for the measurement is taken from.
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