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R&S®FPS-K18 and -K18D
Power Amplifier Measurements
User Manual
(;ÛË02)
1177610002
Version 05
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This manual applies to the following R&S®FPS models with firmware version 1.70 and higher:
●
R&S®FPS4 (1319.2008K04)
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R&S®FPS7 (1319.2008K07)
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R&S®FPS13 (1319.2008K13)
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R&S®FPS30 (1319.2008K30)
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R&S®FPS40 (1319.2008K40)
The following firmware options are described:
●
R&S FPS-K18 (1321.4662.02)
●
R&S FPS-K18D (1321.4956.02)
© 2021 Rohde & Schwarz GmbH & Co. KG
Mühldorfstr. 15, 81671 München, 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.
1177.6100.02 | Version 05 | R&S®FPS-K18 and -K18D
Throughout this manual, products from Rohde & Schwarz are indicated without the ® symbol , e.g. R&S®FPS is indicated as
R&S FPS.
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R&S®FPS-K18 and -K18D
Contents
1 Preface.................................................................................................... 7
1.1 About this Manual......................................................................................................... 7
1.2 Typographical Conventions......................................................................................... 7
2 Welcome to the Amplifier Measurement Application......................... 8
2.1 Starting the Application................................................................................................8
2.2 Understanding the Display Information......................................................................9
3 Measurements and Result Displays...................................................11
4 Configuration........................................................................................32
4.1 Configuration Overview..............................................................................................32
4.2 Performing Measurements.........................................................................................34
Contents
4.3 Designing a Reference Signal....................................................................................35
4.4 Configuring Inputs and Outputs................................................................................43
4.4.1 Selecting and Configuring the Input Source..................................................................43
4.4.2 Configuring the Frequency............................................................................................46
4.4.3 Defining Level Characteristics.......................................................................................47
4.4.4 Configuring Outputs...................................................................................................... 50
4.4.5 Controlling a Signal Generator......................................................................................50
4.4.6 Reference: I/Q File Input............................................................................................... 55
4.5 Triggering Measurements.......................................................................................... 65
4.6 Configuring the Data Capture.................................................................................... 65
4.7 Sweep Configuration.................................................................................................. 68
4.8 Synchronizing Measurement Data............................................................................ 69
4.9 Evaluating Measurement Data................................................................................... 72
4.10 Estimating and Compensating Signal Errors...........................................................74
4.11 Equalizer...................................................................................................................... 75
4.12 Applying System Models............................................................................................76
4.13 Applying Digital Predistortion................................................................................... 79
4.13.1 Polynomial DPD............................................................................................................ 79
4.13.2 Direct DPD (R&S FPS-K18D)....................................................................................... 82
4.14 Configuring Power Measurements............................................................................85
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4.15 Configuring Adjacent Channel Leakage Error (ACLR) Measurements..................86
4.16 Configuring the Parameter Sweep............................................................................ 89
5 Analysis................................................................................................ 92
5.1 Configuring Traces..................................................................................................... 92
5.1.1 Selecting the Trace Information.................................................................................... 92
5.1.2 Exporting Traces........................................................................................................... 94
5.1.3 Detector Settings...........................................................................................................95
5.2 Using Markers............................................................................................................. 96
5.2.1 Configuring Markers......................................................................................................96
5.2.2 Configuring Individual Markers......................................................................................97
5.2.3 Positioning Markers.....................................................................................................100
5.3 Customizing Numerical Result Tables.................................................................... 100
Contents
5.4 Configuring Result Display Characteristics........................................................... 102
5.5 Scaling the X-Axis.....................................................................................................104
5.6 Scaling the Y-Axis.....................................................................................................105
6 Remote Control Commands for Amplifier Measurements............. 108
6.1 Introduction............................................................................................................... 108
6.1.1 Conventions used in Descriptions...............................................................................109
6.1.2 Long and Short Form.................................................................................................. 109
6.1.3 Numeric Suffixes......................................................................................................... 110
6.1.4 Optional Keywords...................................................................................................... 110
6.1.5 Alternative Keywords...................................................................................................110
6.1.6 SCPI Parameters.........................................................................................................111
6.2 Common Suffixes......................................................................................................113
6.3 Selecting the Application......................................................................................... 113
6.4 Configuring the Screen Layout................................................................................117
6.5 Performing Amplifier Measurements...................................................................... 125
6.5.1 Performing Measurements..........................................................................................125
6.5.2 Retrieving Graphical Measurement Results................................................................128
6.5.3 Retrieving Numeric Results.........................................................................................131
6.5.4 Retrieving I/Q Data......................................................................................................207
6.6 Configuring Amplifier Measurements..................................................................... 208
6.6.1 Designing a Reference Signal.....................................................................................209
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6.6.2 Selecting and Configuring the Input Source................................................................223
6.6.3 Configuring the Frequency..........................................................................................225
6.6.4 Defining Level Characteristics.....................................................................................226
6.6.5 Controlling a Signal Generator....................................................................................230
6.6.6 Configuring the Data Capture..................................................................................... 239
6.6.7 Sweep Configuration...................................................................................................244
6.6.8 Synchronizing Measurement Data.............................................................................. 246
6.6.9 Defining the Evaluation Range....................................................................................249
6.6.10 Estimating and Compensating Signal Errors.............................................................. 251
6.6.11 Applying a System Model............................................................................................256
6.6.12 Applying Digital Predistortion...................................................................................... 258
6.6.13 Configuring ACLR Measurements.............................................................................. 269
6.6.14 Configuring Power Measurements..............................................................................275
Contents
6.6.15 Configuring Parameter Sweeps.................................................................................. 276
6.7 Analyzing Results..................................................................................................... 280
6.7.1 Configuring Traces......................................................................................................280
6.7.2 Using Markers............................................................................................................. 285
6.7.3 Configuring Numerical Result Displays.......................................................................296
6.7.4 Configuring the Statistics Table...................................................................................299
6.7.5 Configuring Result Display Characteristics................................................................. 300
6.7.6 Scaling the Diagram Axes...........................................................................................304
6.7.7 Managing Measurement Data.....................................................................................310
6.8 Deprecated Remote Commands for Amplifier Measurements............................. 311
List of commands.............................................................................. 312
Index....................................................................................................331
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Contents
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1 Preface
1.1 About this Manual
This Amplifier 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 FPS User Manual.
The main focus in this manual is on the amplifier measurement results and the tasks
required to obtain them. The following topics are included:
●
Welcome to the Amplifier application
Introduction to and getting familiar with the application
●
Measurements and result displays
Details on supported measurements and their result types
●
Configuration and analysis
A concise description of all functions and settings available to configure and analyze amplifier measurements with their corresponding remote control command
●
Remote commands for amplifier measurements
Remote commands required to configure and perform amplifier 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 FPS User Manual)
●
List of remote commands
Alpahabetical list of all remote commands described in the manual
●
Index
Preface
Typographical Conventions
1.2 Typographical Conventions
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.
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2 Welcome to the Amplifier Measurement
Application
The R&S FPS-K18 is a firmware application that adds functionality to measure the efficiency of amplifiers with the R&S FPS signal analyzer. You extend the amplifier application with the R&S FPS-K18D, which adds direct DPD functionality.
This user manual contains a description of the functionality that the application provides, including remote control operation.
Functions that are not discussed in this manual are the same as in the base unit and
are described in the R&S FPS user manual. The latest versions of the manuals are
available for download at the product homepage.
http://www.rohde-schwarz.com/product/FPS.html.
Installation
Find detailed installing instructions in the getting started or the release notes of the
R&S FPS.
Welcome to the Amplifier Measurement Application
Starting the Application
● Starting the Application............................................................................................. 8
● Understanding the Display Information.....................................................................9
2.1 Starting the Application
The amplifier measurement application adds a new type of measurement to the
R&S FPS.
To activate the amplifier application
1. Press the [MODE] key on the front panel of the R&S FPS.
A dialog box opens that contains all operating modes and applications currently
available on your R&S FPS.
2. Select the "Amplifier" item.
The R&S FPS opens a new measurement channel for the amplifier application.
All settings specific to amplifier measurements are in their default state.
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2.2 Understanding the Display Information
The following figure shows the display as it looks for amplifier measurements. All different information areas are labeled. They are explained in more detail in the following
sections.
Welcome to the Amplifier Measurement Application
Understanding the Display Information
Figure 2-1: Screen layout of the amplifier measurement application
1 = Toolbar
2 = Channel bar
3 = Result display
4 = Status bar
5 = Softkey bar
For a description of the elements not described below, refer to the getting started of the
R&S FPS.
Channel bar information
The channel bar contains information about the current measurement setup, progress
and results.
Figure 2-2: Channel bar of the amplifier application
Ref Level Current reference level of the analyzer.
Att Current attenuation of the analyzer.
Freq Frequency the signal is transmitted on.
Meas Time Length of the signal capture.
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Meas BW Bandwidth with which the signal is recorded.
TTF Time difference between the trigger event and the first sample of the reference
SRate Sample rate with which the signal is recorded.
SGL Indicates that single sweep mode is active.
Count The current signal count for measurement tasks that involve a specific number
X Axis X-axis value that is currently measured.
Y Axis Y-axis value that is currently measured.
Window title bar information
For each diagram, the header provides the following information:
Welcome to the Amplifier Measurement Application
Understanding the Display Information
signal (= beginning of a frame).
of subsequent sweeps (for example the parameter sweep).
1
Figure 2-3: Window title bar information of the amplifier application
1 = Window number
2 = Window type
3 = Trace color and number
4 = Trace mode
Blue color = Window is selected
2 3 4
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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3 Measurements and Result Displays
Note that you can use the R&S FPS-K18 with the sequencer that is available with the
R&S FPS. The functionality is the same as in the spectrum application. Refer to the
R&S FPS user manual for more information.
Adjacent Channel Leakage Error (ACLR)..................................................................... 11
AM/AM.......................................................................................................................... 12
AM/PM.......................................................................................................................... 13
EVM vs Power...............................................................................................................14
Error Vector Spectrum...................................................................................................15
Gain Compression........................................................................................................ 16
Gain Deviation vs Time.................................................................................................17
Magnitude Capture........................................................................................................17
Parameter Sweep......................................................................................................... 18
└ Parameter Sweep: Diagram............................................................................18
└ Parameter Sweep: Table.................................................................................19
Phase Deviation vs Time...............................................................................................20
Raw EVM...................................................................................................................... 20
Numeric Result Summary............................................................................................. 21
└ Results to check modulation accuracy............................................................23
└ Results to check power characteristics...........................................................26
Spectrum FFT............................................................................................................... 28
Time Domain.................................................................................................................29
└ Scale of the x-axis (display settings for the time domain)...............................29
└ Scale of the y-axis (display settings for the time domain)...............................30
Statistics Table.............................................................................................................. 30
Measurements and Result Displays
Adjacent Channel Leakage Error (ACLR)
The "ACLR" result display shows the power characteristics of the transmission (Tx)
channel and its neighboring channel(s).
The ACLR measurement in the R&S FPS-K18 is a measurement based on I/Q data.
Thus, its results are calculated by the same I/Q data as the rest of the results (like the
EVM). Note that the supported channel bandwidth is limited by the I/Q bandwidth of the
analyzer you are using.
The results are provided in numerical form in a table. The table is made up out of two
parts, one part containing the characteristics of the Tx channel, the other containing
those of the neighboring channels.
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The table contains the following information.
●
Channel
Shows the type of channel.
●
Bandwidth
Shows the channel's bandwidth.
●
Offset (neighboring channels only)
Shows the frequency offset between the center frequency of the adjacent (or alternate) channel and the center frequency of the transmission channel.
●
Power
Shows the power of the transmission channel, or the power of the upper / lower
neighboring channel.
The result is calculated over the complete capture buffer, not just the evaluation
range.
●
Balanced
Shows the difference between the lower and upper adjacent channel power
("Lower Channel" - "Upper Channel").
For more information on configuring the ACP measurement, see Chapter 4.15, "Con-
figuring Adjacent Channel Leakage Error (ACLR) Measurements", on page 86.
Remote command:
Selection: LAY:ADD? '1',LEFT,ACP
Result query: CALCulate<n>:MARKer<m>:FUNCtion:POWer:RESult?
on page 270
Measurements and Result Displays
AM/AM
The "AM/AM" result display shows nonlinear effects of the DUT. It shows the amplitude
at the DUT input against the amplitude at the DUT output.
The ideal AM/AM curve would be a straight line at 45°. However, nonlinear effects
result in a measurement curve that does not follow the ideal curve. When you drive the
amplifier into saturation, the curve typically flattens at high input levels.
The width of the AM/AM trace is an indicator of memory effects: the larger the width of
the trace, the more memory effects occur. The AM/AM Curve Width is shown in the
numerical Result Summary.
Both axes show the power of the signal in dBm.
You can analyze the AM/AM characteristics of the measured signal and the modeled
signal.
●
Measured signal
Shows the AM/AM characteristics of the DUT.
The software uses the reference signal in combination with the synchronized measurement signal to calculate a software model that describes the characteristics of
the device under test.
The measured signal is represented by a colored cloud of values. The cloud is
based on the recorded samples. If samples have the same values (and would thus
be superimposed), colors represent the statistical frequency with which a certain
input / output level combination occurs. Blue pixels represent low statistical frequencies, red pixels high statistical frequencies. A color map is provided within the
result display.
●
Modeled signal
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Shows the AM/AM characteristics of the model that has been calculated. The modeled signal is calculated by applying the DUT model to the reference signal.
When the model matches the characteristics of the DUT, the characteristics of the
model signal are the same as those of the measured signal (minus noise).
The modeled signal is represented by a line trace.
When system modeling has been turned off, this trace is not displayed.
All traces include the digital predistortion, when you have turned on that feature.
Measurements and Result Displays
Remote command:
Selection: LAY:ADD? '1',LEFT,AMAM
Result query: TRACe<n>[:DATA]? on page 129
AM/PM
The "AM/PM" result display shows nonlinear effects of the DUT. It shows the phase difference between DUT input and output for each sample of the synchronized measurement signal.
The ideal AM/PM curve would be a straight line at 0°. However, nonlinear effects result
in a measurement curve that does not follow the ideal curve. Typically, the curve drifts
from a zero phase shift, especially at high power levels when you drive the amplifier
into saturation.
The width of the AM/PM trace is an indicator of memory effects: the larger the width of
the trace, the more memory effects occur. The AM/PM curve width is shown in the
numerical Result Summary.
The x-axis shows the levels of all samples of the reference signal (input power) or the
measurement signal (output power) in dBm. You can select the reference of the x-axis
(input or output power) in the "Result Configuration" dialog box.
The y-axis shows the phase of the signal for the corresponding power level. The unit is
either rad or degree, depending on your phase unit selection in the "Result Configuration" dialog box.
You can analyze the AM/PM characteristics of the real DUT or of the modeled DUT.
●
Measured signal
Shows the AM/PM characteristics of the DUT.
The software uses the reference signal together with the synchronized measurement signal to calculate a software model that describes the characteristics of the
device under test.
The measured signal is represented by a colored cloud of values. The cloud is
based on the recorded samples. If samples have the same values (and would thus
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be superimposed), colors represent the statistical frequency with which a certain
input / output level combination occurs. A color map is provided within the result
display.
●
Modeled signal
Shows the AM/PM characteristics of the model that has been calculated. The modeled signal is calculated by applying the DUT model to the reference signal.
When the model matches the characteristics of the DUT, the characteristics of the
modeled signal are the same as those of the measured signal (minus noise).
The modeled signal is represented by a line trace.
When system modeling has been turned off, this trace is not displayed.
All traces include the digital predistortion, when you have turned on that feature.
Measurements and Result Displays
Remote command:
Selection: LAY:ADD? '1',LEFT,AMPM
Result query: TRACe<n>[:DATA]? on page 129
EVM vs Power
The "EVM vs Power" result display shows the EVM against the measured power values.
The ideal EVM vs power curve would be a straight line at 0 %. However, among other
effects such as noise, nonlinear effects of the DUT cause an increase of the EVM.
Nonlinear effects usually occur on high power levels that drive the power amplifier into
saturation.
The x-axis shows the levels of all samples of the reference signal (input power) or the
measurement signal (output power) in dBm. You can select the reference of the x-axis
(input or output power) in the "Result Configuration" dialog box.
The y-axis shows the EVM of the signal for the corresponding power level in %.
All traces include the digital predistortion, when you have turned on that feature.
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Remote command:
Selection: LAY:ADD? '1',LEFT,AMEV
Result query: TRACe<n>[:DATA]? on page 129
Error Vector Spectrum
The "Error Vector Spectrum" result display shows the error vector (EV) signal in the
spectrum around the center frequency.
The EV is a measure of the modulation accuracy. It compares two signals and shows
the distance of the measured constellation points and the ideal constellation points.
The unit is dB.
You can compare the measured signal against the reference signal and against the
modeled signal.
●
Measured signal against reference signal
Trace 1 compares measured signal and the reference signal.
To get useful results, the calculated linear gain is compensated to match both signals.
Depending on the DUT, noise and nonlinear effects may have been added to the
measurement signal. These effects are visualized by this trace.
●
Measured signal against modeled signal
Trace 2 compares measured signal and the modeled signal.
The EVM between the measured and modeled signal indicates the quality of the
DUT modeling. If the model matches the DUT behavior, the modeling error is zero
(or is merely influenced by noise).
This result display shows changes in the model and its parameters and thus allows
you to optimize the modeling.
When system modeling has been turned off, this trace is not displayed.
Measurements and Result Displays
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Remote command:
Selection: LAY:ADD? '1',LEFT,SEVM
Result query: TRACe<n>[:DATA]? on page 129
Gain Compression
The "Gain Compression" result display shows the gain and error effects of the DUT
against the DUT input or output power.
The gain is the ratio of the input and output power of the DUT.
The x-axis shows the levels of all samples of the reference signal (input power) or the
measurement signal (output power) in dBm. You can select the reference of the x-axis
(input or output power) in the "Result Configuration" dialog box.
The y-axis shows the gain in dB.
The ideal gain compression curve would be a straight horizontal line. However, nonlin-
ear effects result in a measurement curve that does not follow the ideal curve. In addition, the curve widens at very low input levels due to noise influence.
The width of the gain compression trace is an indicator of memory effects: the larger
the width of the trace, the more memory effects occur.
You can analyze the gain characteristics of the measured signal and the modeled signal.
●
Measured signal
Shows the gain characteristics of the DUT.
The software uses the reference signal in combination with the synchronized measurement signal to calculate a software model that describes the characteristics of
the device under test.
The measured gain is represented by a colored cloud of values. The cloud is
based on the recorded samples. If samples have the same values (and would thus
be superimposed), colors represent the statistical frequency with which a certain
input / output level combination occurs. Blue pixels represent low statistical frequencies, red pixels high statistical frequencies. A color map is provided within the
result display.
●
Modeled signal
Shows the gain characteristics of the model that has been calculated. The modeled
signal is calculated by applying the DUT model to the reference signal.
When the model matches the characteristics of the DUT, the characteristics of the
model signal are the same as those of the measured signal (minus noise).
The modeled signal is represented by a line trace.
When system modeling has been turned off, this trace is not displayed.
In addition, one or more horizontal lines can appear in the result display.
●
One line to indicate each compression point (1 dB, 2 dB and 3 dB).
●
One line to indicate the reference point (0 dB compression) that the compression
points refer to.
Measurements and Result Displays
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Remote command:
Selection: LAY:ADD? '1',LEFT,GC
Result query: TRACe<n>[:DATA]? on page 129
Gain Deviation vs Time
The "Gain Deviation vs Time" result display shows the deviation of each measured signal sample from the average gain of the measured signal.
The x-axis shows the time in seconds. The y-axis shows the gain deviation in dB.
The displayed results are based on the synchronized measurement data (represented
by the green bar in the capture buffer).
Note that the result query and trace export only work for unencrypted reference signal
waveform files.
Measurements and Result Displays
Remote command:
Selection: LAY:ADD? '1',LEFT,GDVT
Result query: TRACe<n>[:DATA]? on page 129
Magnitude Capture
The "Magnitude Capture" result display contains the raw data that has been recorded
and thus represents the characteristics of the DUT.
The capture buffer shows the signal level over time. The unit is either dBm.
The raw data is source for all further evaluations. You can also use the data in the cap-
ture buffer to identify the causes for possible unexpected results.
When you synchronize the reference signal and the measured signal, the synchronized
area is indicated by a horizontal green bar on the bottom of the diagram.
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The current reference level is indicated by a red horizontal line.
The green bar at the bottom shows the current frame. In I/Q averaging mode, the aver-
age value is shown. In trace statistics mode, multiple values are possible. The currently
selected value is symbolized by a blue bar.
Remote command:
Selection (RF): LAY:ADD? '1',LEFT,RFM
Result query: TRACe<n>[:DATA]? on page 129
Measurements and Result Displays
Parameter Sweep
The "Parameter Sweep" result display is a result display that shows a result of the DUT
(for example the EVM) against two (custom) measurement parameters. The results of
this measurement are displayed in graphical and numerical form.
The parameter sweep is a good way, for example, to find the location of the ideal delay
time of the RF signal and the envelope signal if you are measuring an amplifier that
supports envelope tracking. You can also use the parameter sweep to determine the
characteristics and behavior of an amplifier over different frequencies and levels.
For more information about supported parameters and how to set them up see "Select-
ing the data to be evaluated during the parameter sweep" on page 90.
Parameter Sweep: Diagram ← Parameter Sweep
The parameter sweep diagram is a graphical representation of the parameter sweep
results. The results are either represented as a two-dimensional trace or as a threedimensional trace, depending on whether you are performing a parameter sweep with
one or two parameters.
In a two-dimensional diagram, the y-axis always shows the result. The displayed result
depends on the result type you have selected. The information displayed on the x-axis
depends on the parameter you have selected for evaluation (for example the EVM over
a given frequency range). Values between measurement point are interpolated. Basically, you can interpret the two-dimensional diagram as follows (example): "at a frequency of x Hz, the EVM has a value of y."
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In a three-dimensional diagram, the z-axis always shows the result. The information on
the other two axes is arbitrary and depends on the parameters you have selected for
evaluation. For a better readability, the result values in the three-dimensional diagram
are represented by a colored trace: low values have a blue color, while high values
have a red color. Values between measurement point are interpolated. Basically, you
can interpret the three-dimensional diagram as follows (example): "at a frequency of
x Hz and a level of y, the EVM has a value of z."
Parameter Sweep: Table ← Parameter Sweep
The parameter sweep table shows the minimum and maximum results for all available
result types in numerical form. For each result type, the location where the minimum
and maximum result has occurred is displayed.
Example:
Measurements and Result Displays
A minimum EVM of 0.244 % and a maximum EVM of 0.246 % has been measured
(first and second row). The minimum EVM has been measured at a frequency of
30 MHz and an output power of 0 dBm. The maximum EVM has been measured at a
frequency of 10 MHz and an output power of 0 dBm.
The following result types are evaluated in the parameter sweep.
Result Description
EVM Error vector magnitude between synchronized reference and mea-
surement signal.
ACLR Power of the transmission channel.
ACLR Adj Upper / Lower Power of the adjacent channels (upper and lower).
ACLR Balanced (Adj, Alt1 and
Alt2)
RMS Power RMS signal power at the DUT output.
Gain Gain of the DUT.
Crest Factor Out Crest factor of the signal at the DUT output. The crest factor is the
Curve Width (AM/AM, AM/PM) Spread of the samples in the AM/AM (or AM/PM) result display com-
Power Out Signal power at the DUT output.
Difference between the lower and upper adjacent channel power
ratio of the RMS and peak power.
pared to the ideal AM/AM (or AM/PM) curve.
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Result Description
Measurements and Result Displays
Compression Point (1 dB / 2 dB /
3 dB)
Bal ACLR Magnitude Shows the difference between the lower and upper adjacent channel
Input power where the gain deviates by 1 dB, 2 dB or 3 dB from a reference gain (see "Configuring compression point calculation"
on page 85).
power.
Remote command:
Chapter 6.5.3.3, "Retrieving Results of the Parameter Sweep Table", on page 143
Phase Deviation vs Time
The "Phase Deviation vs Time" result display shows the phase deviation of the measured signal compared to the reference signal over time.
The x-axis shows the time in seconds. The y-axis shows the phase deviation in
degree.
The displayed results are based on the synchronized measurement data (represented
by the green bar in the capture buffer).
Note that the result query and trace export only work for unencrypted reference signal
waveform files.
Remote command:
Selection: LAY:ADD? '1',LEFT,PDVT
Result query: TRACe<n>[:DATA]? on page 129
Raw EVM
The "Raw EVM" result display shows the error vector magnitude of the signal over
time.
The EVM is a measure of the modulation accuracy. It compares two signals and shows
the distance of the measured constellation points and the ideal constellation points.
You can compare the measured signal against the reference signal and against the
modeled signal.
●
Measured signal against reference signal
Trace 1 compares the measured signal and the reference signal.
To get useful results, the calculated linear gain is compensated to match both signals.
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Depending on the DUT, noise and nonlinear effects may have been added to the
measurement signal. These effects are visualized by this trace.
●
Measured signal against modeled signal
Trace 2 compares the measured signal and the modeled signal.
The EVM between the measured and modeled signal indicates the quality of the
DUT modeling. If the model matches the DUT behavior, the modeling error is zero
(or is merely influenced by noise).
This result display shows changes in the model and its parameters and thus allows
you to optimize the modeling.
When system modeling has been turned off, this trace is not displayed.
Note that the raw EVM is calculated for each sample that has been recorded. Thus, the
raw EVM can differ from EVM values that are calculated according to a specific mobile
communication standard that apply special rules to calculate the EVM, for example
LTE.
Measurements and Result Displays
Remote command:
Selection: LAY:ADD? '1',LEFT,REVM
Result query: TRACe<n>[:DATA]? on page 129
Numeric Result Summary
The "Result Summary" shows various measurement results in numerical form, combined in one table.
The table is split in two parts.
●
The first part shows the modulation accuracy
●
The second part shows the power characteristics of the RF signal
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For each result type, several values are displayed.
●
Current
Value measured during the last sweep.
For measurements that evaluate each captured sample, this value represents the
average value over all samples captured in the last sweep.
●
Min
For measurements that evaluate each captured sample, this value represents the
sample with lowest value captured in the last sweep.
●
Max
For measurements that evaluate each captured sample, this value represents the
sample with the highest value captured in the last sweep.
●
Unit
Unit of the result.
Results that evaluate each captured sample
●
Raw EVM and Raw Model EVM
●
Power In and Power Out
Note: When synchronization has failed or has been turned off, some results may be
unavailable.
Remote command:
Selecting the result display: LAY:ADD? '1',LEFT,RTAB
Querying results: see Chapter 6.5.3, "Retrieving Numeric Results", on page 131
Measurements and Result Displays
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Results to check modulation accuracy ← Numeric Result Summary
Raw EVM Error vector magnitude between synchronized reference and measured sig-
Measurements and Result Displays
nal.
FETCh:MACCuracy:REVM:CURRent[:RESult]? on page 136
Raw Model EVM Error vector magnitude between synchronized measured and model signal.
FETCh:MACCuracy:RMEV:CURRent[:RESult]? on page 136
Frequency Error Difference of the RF frequency of the reference signal compared to the mea-
sured signal.
Note that a frequency error is not available if the frequency error estimation is
switched off. See also Chapter 4.10, "Estimating and Compensating Signal
Errors", on page 74.
FETCh:MACCuracy:FERRor:CURRent[:RESult]? on page 133
Sample Rate Error Sample rate difference between reference and measured signal.
Note that a sample rate error is not available if the sample rate error estimation is switched off. See also Chapter 4.10, "Estimating and Compensating
Signal Errors", on page 74.
FETCh:MACCuracy:SRERror:CURRent[:RESult]? on page 136
Magnitude Error Difference in magnitude between the reference signal and the measured sig-
nal.
FETCh:MACCuracy:MERRor:CURRent[:RESult]? on page 134
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Phase Error Phase difference between reference and measured signal.
Quadrature Error Phase deviation of the 90° phase difference between the real (I) and imagi-
Measurements and Result Displays
FETCh:MACCuracy:PERRor:CURRent[:RESult]? on page 135
nary (Q) part of the signal.
Within an ideal transmitter, the I and Q signal parts are mixed with an angle of
90° by the I/Q output mixer. Due to hardware imperfections, the signal delay of
I and Q can be different and thus lead to an angle non-equal to 90°.
Note that quadrature rate error is not available if the I/Q Imbalance estimation
is switched off. See also Chapter 4.10, "Estimating and Compensating Signal
Errors", on page 74.
FETCh:MACCuracy:QERRor:CURRent[:RESult]? on page 135
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Gain Imbalance Gain difference between the real (I) and imaginary (Q) part of the signal.
Measurements and Result Displays
This effect is typically generated by two separate amplifiers with a different
gain in the I and Q path of the analog baseband signal generation.
Note that gain imbalance is not available if the I/Q Imbalance estimation is
switched off. See also Chapter 4.10, "Estimating and Compensating Signal
Errors", on page 74.
FETCh:MACCuracy:GIMBalance:CURRent[:RESult]? on page 133
I/Q Imbalance Combination of Quadrature error and Gain imbalance.
The I/Q imbalance parameter is a representation of the combination of Quadrature error and gain imbalance.
Note that I/Q imbalance is not available if the I/Q imbalance estimation is
switched off. See also Chapter 4.10, "Estimating and Compensating Signal
Errors", on page 74.
FETCh:MACCuracy:IQIMbalance:CURRent[:RESult]? on page 134
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I/Q Offset Shift of the measured signal compared to the ideal I/Q constellation in the I/Q
Measurements and Result Displays
plane.
Note that I/Q offset is not available if the I/Q Offset estimation is switched off.
See also Chapter 4.10, "Estimating and Compensating Signal Errors",
on page 74.
FETCh:MACCuracy:IQOFfset:CURRent[:RESult]? on page 134
Amplitude Droop Amplitude droop is a measure of the change in magnitude of the signal over
the frame (reference signal) being measured in dB.
Note that amplitude droop is not available if the amplitude droop estimation is
switched off. See also Chapter 4.10, "Estimating and Compensating Signal
Errors", on page 74.
Results to check power characteristics ← Numeric Result Summary
Power In Signal power at the DUT input when reference signal is active. The signal
generator level may change during direct DPD, but this result summary value
will always refer to the reference signal – not the DPD signal.
FETCh:POWer:INPut:CURRent[:RESult]? on page 139
Power Out Signal power at the DUT output.
It is the RMS power of:
●
The currently selected frame, if R&S FPS-K18 has successfully
synchronized.
●
The current capture buffer, if R&S FPS-K18 has not synchronized.
FETCh:POWer:OUTPut:CURRent[:RESult]? on page 140
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Gain Average gain calculated over all samples of the Gain Compression trace.
Measurements and Result Displays
noise in
output signal
gain
Note that gain is not necessarily equal to the ratio "Power Out" / "Power In".
Gain only describes the ratio of the correlated signal in "Power Out" to "Power
In".
Gain is always referenced to the reference signal power, i.e. when DPD
changes the generator level, the gain is still referenced to the input power of
the reference signal - not the DPD signal.
Example: If the output signal contains the same amount of noise as the correlated signal (e.g. signal is 0 dBm and noise power is also 0 dBm), "Power Out"
will show the sum (3 dBm). However, assuming an input signal power of
-10 dBm, gain will only show 10 dB, not 13 dB.
FETCh:POWer:GAIN:CURRent[:RESult]? on page 139
total output
signal
correlated
output signal
input signal
Crest Factor In Crest factor of the signal at the DUT input. The crest factor is the ratio of the
RMS and peak power.
FETCh:POWer:CFACtor:IN:CURRent[:RESult]? on page 138
Crest Factor Out Crest factor of the signal at the DUT output. The crest factor is the ratio of the
RMS and peak power.
FETCh:POWer:CFACtor:OUT:CURRent[:RESult]? on page 138
AM/AM Curve Width Vertical spread of the samples in the AM/AM result display.
The AM/AM curve width shows the standard deviation of the output voltage or
the output phase deviation within a +/- 1% range around the mean amplitude
in volt.
Output
amplitude
+/- 1%
σ of output
amplitude
in this range
10,5
Input amplitude
linear normalized
FETCh:AMAM:CWIDth:CURRent[:RESult]? on page 137
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AM/PM Curve Width Vertical spread of the samples in the AM/PM result display.
Measurements and Result Displays
The AM/PM curve width shows the standard deviation of the output voltage or
the output phase deviation within a +/- 1% range around the mean amplitude
in volt.
Output
amplitude
+/- 1%
σ of output
amplitude
in this range
FETCh:AMPM:CWIDth:CURRent[:RESult]? on page 138
10,5
Input amplitude
linear normalized
Compression Point (1 dB / 2
dB / 3 dB)
Input power where the gain deviates by 1 dB, 2 dB or 3 dB from a reference
gain (see "Configuring compression point calculation" on page 85).
In the graphical result, the compression points are indicated by horizontal red
lines.
FETCh:POWer:P1DB:CURRent[:RESult]? on page 140
FETCh:POWer:P2DB:CURRent[:RESult]? on page 140
FETCh:POWer:P3DB:CURRent[:RESult]? on page 141
Output Compression Point
(1 dB / 2 dB / 3 dB)
Output power where the gain deviates by 1 dB, 2 dB or 3 dB from a reference
gain.
Uses identical operating points as "Compression Point (1 dB / 2 dB / 3 dB)",
but is identified by output power at compression point rather than input power.
FETCh:POWer:OUTPut:P1DB:CURRent[:RESult]? on page 141
FETCh:POWer:OUTPut:P2DB:CURRent[:RESult]? on page 142
FETCh:POWer:OUTPut:P3DB:CURRent[:RESult]? on page 142
Spectrum FFT
The "Spectrum FFT" result display shows the frequency spectrum of the signal.
The spectrum FFT result shows the signal level in the spectrum around the center fre-
quency. The unit is dBm.
You can display the spectrum of the measured signal and the reference signal. In the
best case, the measured signal has the same shape as the reference signal.
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Remote command:
Selection (RF): LAY:ADD? '1',LEFT,RFS
Result query: TRACe<n>[:DATA]? on page 129
Time Domain
The "Time Domain" result display shows the signal characteristics over time.
It is similar to the "Power vs Time" and "Magnitude Capture" result displays in that it
shows the signal characteristics over time. However, it deliberately shows only a very
short period of the signal. You can thus use it to compare various aspects of the signal,
especially the timing of the displayed signals, in a single result display.
●
Measured signal
Trace 1 shows the characteristics of the measured signal over time. The data
should be the same as the results shown in the Magnitude Capture RF result display.
In the best case, the measured signal is the same as the reference signal.
●
Modeled signal
Trace 2 shows the characteristics of the modeled signal. When system modeling
has been turned off, this trace is not displayed.
If the model matches the behavior of the DUT, the characteristics of the signal are
the same as those of the measured signal (minus the noise).
●
Reference signal
Trace 3 shows the characteristics of the reference signal. The reference signal
present at the DUT input represents the ideal signal.
Measurements and Result Displays
Remote command:
Selection: LAY:ADD? '1',LEFT,TDOM
Result query: TRACe<n>[:DATA]? on page 129
Scale of the x-axis (display settings for the time domain) ← Time Domain
The scale of the x-axis depends on your configuration in the "Display Settings" dialog
box.
The logic is as follows:
●
When you select automatic scaling (➙ "Position: Auto") and synchronization has
failed, the application searches for the peak level in the capture buffer and shows
the signal around the peak for the "Duration" that has been defined.
●
When you select automatic scaling (➙ "Position: Auto") and synchronization is OK,
the application searches for the peak level in the synchronized area of the capture
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buffer and shows the signal around the peak for the "Duration" that has been
defined.
●
When you select manual scaling (➙ "Position: Manual") and synchronization has
failed, the x-axis starts at an "Offset" relative to the first sample in the capture buffer. The end of the x-axis depends on the "Duration" you have defined.
●
When you select manual scaling (➙ "Position: Manual") and synchronization is OK,
the x-axis starts at an "Offset" relative to the first sample in the synchronized area
of the capture buffer. The end of the x-axis depends on the "Duration" you have
defined.
Note: The "Display Settings" for the time domain are only available after you have
selected the "Specifics for: Time Domain" item from the corresponding dropdown menu
at the bottom of the dialog box.
Scale of the y-axis (display settings for the time domain) ← Time Domain
The scale of the y-axis also depends on your configuration.
The signal characteristics displayed in the time domain result display all have a differ-
ent unit. Therefore, the application provides a feature that normalizes all results to 1
(see "Configuring the time domain result display" on page 102). Normalization makes
it easier to compare the timing between the traces. By default, normalization is on.
Note that you can normalize each Time Domain window individually.
Unnormalized results are displayed in their respective unit.
Measurements and Result Displays
Statistics Table
The results for the statistics table are available only after the statistics mode has been
activated using [SENSe:]SWEep:STATistics[:STATe] on page 245. If statistics
mode is switched off, the statistics table stays empty.
Each value in the statistics table has different rows describing a single frame: Average,
Std. Dev, Maximum and Minimum. This is similar to the Numeric Result Summary.
The different color codes represent different result values:
●
Blue
Result of the current result range. The selected values are updated when the user
sweeps through the result range selection.
●
Green
In I/Q averaging mode, the values in the green area are identical to the ones in the
black background area.
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In trace statistics mode, the green area refers to all frames of the current capture
buffer, whereas the black area refers to all measured frames (including previous
capture buffers). Statistics is always done over sweep “Count” frames and then is
being reset, unless the moving average switch is activated. In this case, infinite statistics is executed.
●
Black / No selection
Statistical results that can also be based on result ranges that were captured in
previous measurement sweeps.
Remote command:
Adding statistics table: LAY:ADD? '1',LEFT,STAB
Querying results: Chapter 6.5.3.4, "Retrieving Results of the Statistics Table",
on page 154
Configuring statistics table: Chapter 6.7.4, "Configuring the Statistics Table",
on page 299
Navigating through results ranges found in a capture: CONFigure:RESult:RANGe[:
SELected] on page 245
Measurements and Result Displays
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4 Configuration
● Configuration Overview...........................................................................................32
● Performing Measurements......................................................................................34
● Designing a Reference Signal.................................................................................35
● Configuring Inputs and Outputs.............................................................................. 43
● Triggering Measurements....................................................................................... 65
● Configuring the Data Capture................................................................................. 65
● Sweep Configuration...............................................................................................68
● Synchronizing Measurement Data..........................................................................69
● Evaluating Measurement Data................................................................................72
● Estimating and Compensating Signal Errors.......................................................... 74
● Equalizer................................................................................................................. 75
● Applying System Models.........................................................................................76
● Applying Digital Predistortion.................................................................................. 79
● Configuring Power Measurements..........................................................................85
● Configuring Adjacent Channel Leakage Error (ACLR) Measurements...................86
● Configuring the Parameter Sweep..........................................................................89
Configuration
Configuration Overview
4.1 Configuration Overview
Throughout the measurement channel configuration, an overview of the most important
currently defined settings is provided in the "Overview". The "Overview" is displayed
when you select the "Overview" icon, which is available at the bottom of all softkey
menus.
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 and analysis by stepping through the dialog boxes
as indicated in the "Overview".
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In particular, the "Overview" provides quick access to the following configuration dialog
boxes (listed in the recommended order of processing):
1. Reference Signal
See Chapter 4.3, "Designing a Reference Signal", on page 35.
2. Input and output
See Chapter 4.4, "Configuring Inputs and Outputs", on page 43.
3. Trigger
See Chapter 4.5, "Triggering Measurements", on page 65.
4. Data Acquisition
See Chapter 4.6, "Configuring the Data Capture", on page 65.
5. Synchronization, error estimation and compensation
See Chapter 4.8, "Synchronizing Measurement Data", on page 69.
See Chapter 4.10, "Estimating and Compensating Signal Errors", on page 74.
6. Measurement
Modeling: see Chapter 4.12, "Applying System Models", on page 76.
DPD: see Chapter 4.13, "Applying Digital Predistortion", on page 79.
Configuration
Configuration Overview
7. Result configuration
See Chapter 5, "Analysis", on page 92.
8. Display configuration
See Chapter 3, "Measurements and Result Displays", on page 11.
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 measurement 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.
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 FPS
(except for the default channel)!
Remote command:
SYSTem:PRESet:CHANnel[:EXEC] on page 117
Specific Settings for
The channel may 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.
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The "Overview" and dialog boxes are updated to indicate the settings for the selected
window.
4.2 Performing Measurements
Access: [SWEEP]
The following features control the measurement. They are available in the "Sweep"
menu.
The remote commands required to control the measurement are described in Chap-
ter 6.5.1, "Performing Measurements", on page 125.
Continuous Sweep / Run Cont .....................................................................................34
Single Sweep / Run Single ...........................................................................................34
Continue Single Sweep ................................................................................................34
Continuous Sweep / Run Cont
After triggering, starts the measurement and repeats it continuously until stopped.
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.
Furthermore, the [RUN CONT] key controls the Sequencer, not individual sweeps.
[RUN CONT] starts the Sequencer in continuous mode.
Remote command:
INITiate<n>:CONTinuous on page 126
Configuration
Performing Measurements
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.
Remote command:
INITiate<n>[:IMMediate] on page 126
Continue Single Sweep
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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Remote command:
INITiate<n>:CONMeas on page 125
4.3 Designing a Reference Signal
Access (source: generator): "Overview" > "Reference Signal" > "Current Generator
Waveform"
Access (source: waveform file): "Overview" > "Reference Signal" > "Custom Waveform File"
Access (source: Amplifier application): "Overview" > "Reference Signal" > "Generate
Own Signal"
Many of the results available in the application require a reference signal that
describes the characteristics of the signal you feed into the amplifier.
The reference signal describes the characteristics of the signal that you feed into the
amplifier and whose amplified version is measured by the application. You can define
any signal you want as a reference signal.
Configuration
Designing a Reference Signal
The application provides several methods to design a reference signal:
●
Designing the signal on a generator
(Having a Rohde & Schwarz generator is mandatory for this method.)
●
Designing the signal in a waveform file
●
Designing the signal in the amplifier application
(Having a Rohde & Schwarz generator is mandatory for this method.)
For a list of supported signal generators, refer to the datasheet of the amplifier application.
The remote commands required to configure the reference signal are described in
Chapter 6.6.1, "Designing a Reference Signal", on page 209.
Reference signal information........................................................................................ 36
Using multi-segment waveform files............................................................................. 36
Transferring the reference signal.................................................................................. 37
Designing a reference signal on a signal generator......................................................37
Designing a reference signal in a waveform file............................................................38
Designing a reference signal within the R&S FPS-K18................................................ 40
└ Signal Bandwidth............................................................................................ 41
└ Pulse Duty Cycle.............................................................................................42
└ Signal Length..................................................................................................42
└ Ramp Length.................................................................................................. 42
└ Crest Factor.................................................................................................... 42
└ Waveform File Name...................................................................................... 42
└ Notch Width.................................................................................................... 42
└ Notch Position.................................................................................................43
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Reference signal information
Each tab of the "Reference Signal" dialog box contains some basic information about
the reference signal currently in use.
The information is only displayed when a reference signal has been successfully loaded. When you load a different waveform, the reference signal information is updated
accordingly.
●
Waveform file
Name and path of the waveform file currently in use.
●
Sample rate
The sample rate in the header of the currently used reference signal waveform file
in Hz.
●
Number of samples
Length of the currently used reference signal waveform file in samples.
●
Crest Factor (File)
Crest factor of the whole file currently in use. The crest factor of waveform files is
read from their header. The crest factor of iq.tar files is calculated.
●
Bandwidth (OBW)
The occupied bandwidth of the reference signal currently in use. A calculated
bandwidth that contains 99% of signal power is displayed.
Remote command:
File path: CONFigure:REFSignal:SINFo:FPATh? on page 216
Sample rate: CONFigure:REFSignal:SINFo:SRATe? on page 217
Sample length: CONFigure:REFSignal:SINFo:SLENgth? on page 217
Crest Factor: CONFigure:REFSignal:SINFo:CFACtor? on page 217
OBW: CONFigure:REFSignal:SINFo:OBW? on page 218
Configuration
Designing a Reference Signal
Using multi-segment waveform files
Modern chip technologies implement several communication standards within one chip
and thus increase the requirements in spatial design and test systems. To fulfill the
requirements in the test systems, and to enable a rapid change between different
waveforms containing different test signals, the R&S SMW provides the functionality to
generate multi-segment waveform files. Multi-segment waveform files are files that
contain several different waveforms.
(For more information about creating and using multi-segment waveform files (including examples) refer to the documentation of the R&S SMW.)
When you are testing amplifiers with the amplifier measurement application, you can
use a multi-segment waveform file to create the reference signal. If you use one of
these files, you have to select the segment that you want to use as a reference signal
in the corresponding input field.
Note that the content of the segment you are using for the reference signal must match
the content of the segment used by the ARB of the signal generator. You can select the
segment for the used by the generator in the generator setup.
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Remote command:
CONFigure:REFSignal:SEGMent on page 216
Transferring the reference signal
Both the signal generator and analyzer used in the test setup need to know the characteristics of the reference signal.
●
The signal generator needs that information to generate the signal.
●
The analyzer needs that information for the evaluation of the results.
This is why you have to transfer the signal information to both instruments. The transmission is done through a LAN connection that you have to establish when setting up
the measurement. For more information on that see Chapter 4.4.5, "Controlling a Sig-
nal Generator", on page 50.
●
When you design the reference signal on the signal generator, transfer the signal
information from the generator to the analyzer with the ➙"Read and Load Current
Signal from R&S SMW" button.
You can either design a reference signal with one of the available firmware options
(for example an LTE signal with the R&S SMW-K55) or design a signal in a custom
waveform file. Note that the R&S FPS-K18 does not support all firmware options of
the signal generator.
●
When you load the reference signal from a waveform file or design the signal within
the R&S FPS-K18, transfer the signal information from the analyzer to the generator. Depending on the signal source, you can do this either with the "Load and
Export Selected Waveform File to Generator" or the "Generate and Load Signal
and Export it to Generator" buttons.
When you send the signal information to the generator, the application automatically
configures the generator accordingly.
Transmission state
The LED displayed with the transmission button shows the state of the reference signal
transmission.
The LED is either gray, green or red:
●
Grey LED
Transmission state unknown (for example when you have not yet started the transmission).
●
Green LED
Transmission has been successful.
●
Red LED
Transmission has not been successful.
Make sure that the generator control state is on. Also check if the generator IP
address / computer name are correct and if the connection has been established.
Configuration
Designing a Reference Signal
Designing a reference signal on a signal generator
One way to design a reference signal is to design the signal on the signal generator
itself.
You can design any signal you like, as long as it is storable as an arbitrary waveform
(ARB) file. When you are done, you have to transfer the signal information from the
signal generator to the signal analyzer with the "Read from Generator, Load" button.
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The "Force ARB Mode" switch forces the signal generator to use its ARB mode (arbitrary waveform) rather than its real-time mode, whenever possible. As a result, switching between DPD on and off state is significantly faster. When the "Force ARB Mode"
function is used, the peak power of the generator is read out and used within the process but as a result of this function the RMS power of the generator is modified.
The parameters of the currently active reference signal are described in "Reference
signal information" on page 36.
The "Open Generator Control" button provides functionality to change the generator
settings as described in Chapter 4.4.5, "Controlling a Signal Generator", on page 50.
Configuration
Designing a Reference Signal
Most of the options available for the connected generator are supported by the automatic signal import functionality of the R&S FPS-K18. If the signal import was not successful (indicated by a red LED), you have to transfer the reference signal in another
way (for example with a memory stick).
For a comprehensive description of all features available on the signal generator and
information on how to generate signals, refer to the documentation of the signal generator.
Remote command:
See signal generator documentation.
CONFigure:REFSignal:CGW:AMODe[:STATe] on page 210
CONFigure:REFSignal:CGW:READ on page 210
CONFigure:REFSignal:CGW:LEDState? on page 210
Designing a reference signal in a waveform file
One way to design a reference signal is to define its characteristics in a waveform file
(*.wv or *.iq.tar).
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You can create a waveform file, for example:
●
With the R&S®WinIQSIM2 software package
●
By exporting a signal designed on the signal generator
Basically, this file contains the characteristics of the reference signal. The generator
then generates the reference signal based on the information in the file.
There are two ways to generate the reference signal through a custom waveform file.
●
The generator is connected to the R&S FPS in a LAN, and can be recognized by
the R&S FPS-K18 (Rohde & Schwarz generators only, for example the R&S SMW)
In that case, you can simply transfer the reference signal information to the generator with the features integrated into the R&S FPS-K18. The generator then generates the corresponding signal with the appropriate signal level, and the R&S FPSK18 is able to compare the measured signal to the ideal reference signal.
●
The generator is not connected to the R&S FPS
In that case, you have to load the reference signal information onto the generator
manually and turn off the "Export to Generator" function. Because no exchange of
information is possible between generator and analyzer, it is required to specify the
input level of the signal in the "DUT Peak Input Power" input field.
The parameters of the currently active reference signal are described in "Reference
signal information" on page 36.
The "Open Generator Control" button provides functionality to change the generator
settings as described in Chapter 4.4.5, "Controlling a Signal Generator", on page 50.
For a comprehensive description of all features available on the signal generator and
information on how to generate and export signals to a file, refer to the documentation
of the signal generator.
Configuration
Designing a Reference Signal
To transfer a waveform file from the analyzer to the generator and process it with the
ARB generator of the R&S SMW, for example, proceed as follows:
▶ In the "Custom Waveform" tab, select a file via the "Load, Play on Generator" button.
▶ Transfer the file to the generator with the "Select" button.
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If a waveform is only used as a reference without transferring it to the signal generator,
make sure that the generator control state "Off" is selected in the generator setup dialog.
Remote command:
Select file: CONFigure:REFSignal:CWF:FPATh on page 212
Transfer file: CONFigure:REFSignal:CWF:WRITe on page 212
Transmission state: CONFigure:REFSignal:CWF:LEDState? on page 212
Export file: CONFigure:REFSignal:CWF:ETGenerator[:STATe] on page 211
DUT input power: CONFigure:REFSignal:CWF:DPIPower on page 211
Designing a reference signal within the R&S FPS-K18
One way to design a reference signal is to design the signal within the R&S FPS-K18.
The application provides functionality to design a basic reference signal and saves the
signal characteristics in a waveform file which you have to transfer to the signal generator with the "Generate and Load Signal and Export it to Generator" button.
When the data has been transferred, the signal generator (for example the R&S SMW)
generates the corresponding signal.
The generated signal is a multi-carrier CW signal, whose basic properties, like crest
factor and bandwidth, you can specify as required.
The parameters of the currently active reference signal are described in "Reference
signal information" on page 36.
The "Open Generator Control" button provides functionality to change the generator
settings as described in Chapter 4.4.5, "Controlling a Signal Generator", on page 50.
Configuration
Designing a Reference Signal
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Configuration
Designing a Reference Signal
To generate a reference signal within the application, proceed as follows:
▶ In the "Generate Own Signal" tab, design the reference signal as required.
The application stores the current signal properties as an ARB signal in a waveform
file.
▶ Upload the data to the generator with the "Generate, Play on Generator" button.
You can define the following signal characteristics.
●
"Signal Bandwidth" on page 41
●
"Pulse Duty Cycle" on page 42
●
"Signal Length" on page 42
●
"Ramp Length" on page 42
●
"Crest Factor" on page 42
●
"Waveform File Name" on page 42
●
"Notch Width" on page 42
●
"Notch Position" on page 43
Remote command:
CONFigure:REFSignal:GOS:WRITe on page 216
CONFigure:REFSignal:GOS:LEDState? on page 214
Signal Bandwidth ← Designing a reference signal within the R&S FPS-K18
Defines the bandwidth of the reference signal.
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The bandwidth should not be larger than maximum I/Q bandwidth supported by your
signal analyzer (which depends on the analyzer configuration).
Remote command:
CONFigure:REFSignal:GOS:BWIDth on page 213
Pulse Duty Cycle ← Designing a reference signal within the R&S FPS-K18
Defines the duty cycle of a pulsed reference signal.
The duty cycle of a pulse is the ratio of the pulse duration and the actual length of the
pulse. A duty cycle of 100 % corresponds to a continuous signal.
Example:
The pulse duration is 2 μs. The actual length of the pulse is 1 μs. The duty cycle is
1 μs : 2 μs = 0.5 or 50 %.
Remote command:
CONFigure:REFSignal:GOS:DCYCle on page 213
Signal Length ← Designing a reference signal within the R&S FPS-K18
Defines the number of samples that the reference signal consists of.
A number that is a power of 2 speeds up the internal signal processing. Thus, such a
number should be specified if no other requirements limit the choice of the sample
count.
For more information, see "Pulse Duty Cycle" on page 42.
Remote command:
CONFigure:REFSignal:GOS:SLENgth on page 215
Configuration
Designing a Reference Signal
Ramp Length ← Designing a reference signal within the R&S FPS-K18
Defines the number of samples used to ramp up the pulse to its full power and vice
versa.
Remote command:
CONFigure:REFSignal:GOS:RLENgth on page 215
Crest Factor ← Designing a reference signal within the R&S FPS-K18
Defines the crest factor of the reference signal.
The crest factor shows the RMS power in relation to the peak power.
Remote command:
CONFigure:REFSignal:GOS:CRESt on page 213
Waveform File Name ← Designing a reference signal within the R&S FPS-K18
Defines the name of the waveform file that the reference ARB signal configuration is
stored in.
Remote command:
CONFigure:REFSignal:GOS:WNAMe on page 215
Notch Width ← Designing a reference signal within the R&S FPS-K18
Defines the width of a notch that you can add to the reference signal.
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Within the notch, all carriers of the reference signal have zero amplitude. You can use
the noise notch to, for example, determine the noise power ratio (NPR) before and
after the DPD.
Remote command:
CONFigure:REFSignal:GOS:NWIDth on page 214
Notch Position ← Designing a reference signal within the R&S FPS-K18
Defines an offset for the noise notch relative to the center frequency.
The offset moves the notch to a position outside the center of the signal. You can use
the offset to, for example, generate a one-sided noise signal or to examine asymmetric
distortion effects.
Remote command:
CONFigure:REFSignal:GOS:NPOSition on page 214
4.4 Configuring Inputs and Outputs
Configuration
Configuring Inputs and Outputs
● Selecting and Configuring the Input Source........................................................... 43
● Configuring the Frequency......................................................................................46
● Defining Level Characteristics.................................................................................47
● Configuring Outputs................................................................................................ 50
● Controlling a Signal Generator................................................................................50
● Reference: I/Q File Input.........................................................................................55
4.4.1 Selecting and Configuring the Input Source
Access: "Overview" > "Input / Frontend" > "Input Source"
The R&S FPS-K18 supports the RF input.
● Configuring the RF Input.........................................................................................43
● External Mixer......................................................................................................... 45
● I/Q File.....................................................................................................................45
4.4.1.1 Configuring the RF Input
Access: "Overview" > "Input / Frontend" > "Input Source" > "RF Input"
The RF input captures the RF signal that you are measuring. It is always on.
The RF input source settings are similar to those available in the spectrum application.
For a comprehensive description of these settings, refer to the R&S FPS user manual.
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The remote commands required to configure the RF input are described in Chap-
ter 6.6.2, "Selecting and Configuring the Input Source", on page 223.
Input Coupling ..............................................................................................................44
Impedance ................................................................................................................... 44
YIG-Preselector ............................................................................................................44
Input Coupling
The RF input of the R&S FPS can be coupled by alternating current (AC) or direct current (DC).
AC coupling blocks any DC voltage from the input signal. This is the default setting to
prevent damage to the instrument. Very low frequencies in the input signal may 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 223
Configuration
Configuring Inputs and Outputs
Impedance
For some measurements, the reference impedance for the measured levels of the
R&S FPS 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).
Remote command:
INPut<ip>:IMPedance on page 225
YIG-Preselector
Enables or disables the YIG-preselector, if available on the R&S FPS.
An internal YIG-preselector at the input of the R&S FPS ensures that image frequen-
cies are rejected. However, this 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 FPS, which can lead to image-frequency display.
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.
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Remote command:
INPut<ip>:FILTer:YIG[:STATe] on page 224
4.4.1.2 External Mixer
Access: "Overview" > "Input / Frontend" > "Input Source" > "External Mixer"
Controlling external generators is available with the optional external generator control.
The functionality is the same as in the spectrum application.
For more information about using external generators, refer to the R&S FPS user manual.
4.4.1.3 I/Q File
Access: "Overview" > "Input / Frontend" > "Input Source" > "I/Q File"
Available for I/Q based measurements.
As an alternative to capturing the measurement (I/Q) data live, you can also load previously recorded I/Q data stored in an iq.tar file. The file is then used as the input
source for the application. Files containing multi-channel measurement data are supported.
Configuration
Configuring Inputs and Outputs
However, only the RF capture buffer is filled with I/Q data from the file. Envelope / supply power measurements based on data from the analog baseband interface
(R&S FPS-B71) are not supported in I/Q file mode.
For details on the "I/Q File" input, see the user manual of the I/Q analyzer.
I/Q Input File State........................................................................................................ 45
Select I/Q data file ........................................................................................................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 225
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 must have a specific format (.iq.tar) as described in R&S FPS I/Q
Analyzer and I/Q Input User Manual.
The default storage location for I/Q data files is C:\R_S\INSTR\USER.
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Remote command:
INPut<ip>:FILE:PATH on page 224
4.4.2 Configuring the Frequency
Access: "Overview" > "Input / Output" > "Frequency"
The "Frequency" tab of the "Input / Output" dialog box contains settings to configure
frequency characteristics.
The frequency settings are similar to those available in the spectrum application. For a
comprehensive description of these settings, refer to the R&S FPS user manual.
Configuration
Configuring Inputs and Outputs
The remote commands required to configure the frequency are described in Chap-
ter 6.6.3, "Configuring the Frequency", on page 225.
Center Frequency......................................................................................................... 46
Center Frequency Stepsize...........................................................................................46
Frequency Offset ..........................................................................................................47
Center Frequency
Defines the frequency of the measured signal.
The possible value range depends on the R&S FPS model you have. See the data
sheet for more information about the supported frequency range.
Remote command:
[SENSe:]FREQuency:CENTer on page 225
Center Frequency Stepsize
Defines the step size by which the center frequency is increased or decreased when
the arrow keys are pressed.
When you use the rotary knob the center frequency changes in steps of only 1/10 of
the "Center Frequency Stepsize".
"= Center"
"Manual"
Remote command:
[SENSe:]FREQuency:CENTer:STEP on page 226
Sets the step size to the value of the center frequency and removes
the coupling of the step size to span or resolution 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.
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Frequency Offset
Shifts the displayed frequency range along the x-axis by the defined offset.
This parameter has no effect on the instrument's hardware, or on the captured data or
on data processing. It is simply a manipulation of the final results in which absolute frequency values are displayed. Thus, the x-axis of a spectrum display is shifted by a
constant offset if it shows absolute frequencies. However, if it shows frequencies relative to the signal's center frequency, it is not shifted.
A frequency offset can be used to correct the display of a signal that is slightly distorted
by the measurement setup, for example.
The allowed values range from -1 THz to 1 THz. The default setting is 0 Hz.
Remote command:
[SENSe:]FREQuency:OFFSet on page 226
4.4.3 Defining Level Characteristics
Access: "Overview" > "Input / Output" > "Amplitude"
Configuration
Configuring Inputs and Outputs
The "Amplitude" tab of the "Input / Output" dialog box contains settings to configure the
signal level characteristics.
The level settings are the same as those available in the spectrum application. For a
comprehensive description of these settings, refer to the R&S FPS user manual.
The remote commands required to configure the amplitude are described in Chap-
ter 6.6.4, "Defining Level Characteristics", on page 226.
Functions available in the "Amplitude" dialog box described elsewhere:
●
" Input Coupling " on page 44
●
" Impedance " on page 44
Reference Level ...........................................................................................................48
└ Shifting the Display ( Offset ).......................................................................... 48
Preamplifier (option B22/B24).......................................................................................48
Input Coupling ..............................................................................................................48
Impedance ................................................................................................................... 49
Attenuation Mode / Value ............................................................................................. 49
Using Electronic Attenuation ........................................................................................49
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Reference Level
Defines the expected maximum reference level. Signal levels above this value may not
be measured correctly. This is indicated by an "IF Overload" status display.
The reference level can also be used to scale power diagrams; the reference level is
then used as the maximum on the y-axis.
Since the hardware of the R&S FPS 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-to-noise
ratio).
Remote command:
DISPlay[:WINDow<n>]:TRACe<t>:Y[:SCALe]:RLEVel on page 227
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 FPS
so the application shows correct power results. All displayed power level results are
shifted by this value.
The reference level offset takes level offsets into account that occur after the signal has
passed through the DUT (usually an amplifier). For level offsets occurring before the
DUT, you can define a level offset on the signal generator from within the R&S FPSK18 user interface.
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 FPS must handle. Do not rely on the displayed reference level (internal reference level = displayed reference level - offset).
Remote command:
DISPlay[:WINDow<n>]:TRACe<t>:Y[:SCALe]:RLEVel:OFFSet on page 227
Configuration
Configuring Inputs and Outputs
Preamplifier (option B22/B24)
Switches the preamplifier on and off. If activated, the input signal is amplified by 20 dB.
If option R&S FPS-B22 is installed, the preamplifier is only active below 7 GHz.
If option R&S FPS-B24 is installed, the preamplifier is active for all frequencies.
Remote command:
INPut<ip>:GAIN:STATe on page 229
Input Coupling
The RF input of the R&S FPS can be coupled by alternating current (AC) or direct current (DC).
AC coupling blocks any DC voltage from the input signal. This is the default setting to
prevent damage to the instrument. Very low frequencies in the input signal may 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.
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Remote command:
INPut<ip>:COUPling on page 223
Impedance
For some measurements, the reference impedance for the measured levels of the
R&S FPS 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).
Remote command:
INPut<ip>:IMPedance on page 225
Attenuation Mode / Value
The RF attenuation can be set automatically as a function of the selected reference
level (Auto mode). This 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.
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 may lead to hardware damage.
Remote command:
INPut<ip>:ATTenuation on page 227
INPut<ip>:ATTenuation:AUTO on page 228
Configuration
Configuring Inputs and Outputs
Using Electronic Attenuation
If the (optional) Electronic Attenuation hardware is installed on the R&S FPS, 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.
Note: Electronic attenuation is not available for stop frequencies (or center frequencies
in zero span) above 7 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 may provide a better signal-to-noise ratio, however.
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.
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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.
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 229
INPut<ip>:EATT:AUTO on page 228
INPut<ip>:EATT on page 228
4.4.4 Configuring Outputs
Access: "Overview" > "Input / Output" > "Output"
The "Output" tab of the "Input / Output" dialog box contains settings to configure the
various signal outputs available on the R&S FPS.
Configuration
Configuring Inputs and Outputs
The functionality is the same as in the spectrum application. For more information
about the output functions, refer to the R&S FPS user manual.
4.4.5 Controlling a Signal Generator
Access: "Overview" > "Input / Output" > "Generator Setup"
The "Generator Setup" tab of the "Input / Output" dialog box contains settings to control the signal generator from within the R&S FPS-K18. A remote control connection
between the R&S FPS and the signal generator has to be established to be able to do
so.
Because a signal generator is (mostly) mandatory in the test setup, these features
make measurement configuration as easy as possible. This way, you can control both
analyzer and generator from within the application without having to operate the two
instruments to configure the measurement.
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The remote commands required to configure the generator are described in Chap-
ter 6.6.5, "Controlling a Signal Generator", on page 230.
Configuration
Configuring Inputs and Outputs
State of operation
Most settings have an LED that shows the state of the corresponding setting on the
signal generator.
The LED is either gray, green or red:
●
Grey LED
Configuration state unknown (for example when you have not yet started the transmission).
●
Green LED
Configuration has been successful. Generator has been configured correctly.
●
Red LED
Configuration has not been successful.
Check if the connection between analyzer and generator has been established or if
the IP address has been stated correctly.
Generator details
The "Generator Details" contain information about the connected signal generator, like
the software version or the serial number of the generator.
Updating generator settings
When you change the generator level or frequency in this dialog, the application automatically updates those settings on the generator.
When you use the "Upload All Settings To Generator" button, you can force an update
of all generator settings available in this dialog box. Useful when you change the level
or frequency on the generator itself. In that case, those settings remain the same in the
R&S FPS-K18. To restore the original settings defined within the R&S FPS-K18, use
that button to restore the generator settings.
Remote command:
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CONFigure:GENerator:SETTings:UPDate on page 238
Querying generator settings
Similarly, you can transfer the current generator configuration into the amplifier application with the "Query All Settings From Generator" button.
Note that the center frequency is not updated when you attach the generator frequency
to that of the R&S FPS.
Remote command:
CONFigure:SETTings on page 239
Generator Control State................................................................................................52
IP Address.....................................................................................................................52
RMS Level.....................................................................................................................52
Maximum DUT Input Level............................................................................................53
Attach to Analyzer Frequency.......................................................................................53
Center Frequency......................................................................................................... 53
Reference Frequency....................................................................................................54
Path RF / BB................................................................................................................. 54
Segment........................................................................................................................54
Digital Attenuation.........................................................................................................54
RF Output......................................................................................................................54
Settling Delay................................................................................................................55
Configuration
Configuring Inputs and Outputs
Generator Control State
Turns the communication with a connected signal generator on and off.
When you turn off the generator control, the connection between R&S FPS and gener-
ator is closed. All settings related to the generator connection (level, frequency, IP
address etc.) become unavailable.
Remote command:
CONFigure:GENerator:CONTrol[:STATe] on page 231
IP Address
Opens a dialog box to configure the network properties of the signal generator.
You can connect to the generator either by entering its IP address ("123" button), or its
computer name ("ABC" button).
If you are not sure about the IP address or computer name of your generator, check its
user interface or kindly ask your IT administrator to provide them.
After you have entered IP address or computer name, use "Connect" to establish the
connection. The R&S FPS shows if the connection state, and, if the connection was
successful, the connected generator type.
Remote command:
CONFigure:GENerator:IPConnection:ADDRess on page 234
CONFigure:GENerator:IPConnection:LEDState? on page 234
RMS Level
Defines the RMS level of the signal that is generated.
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When you define the RMS level here, the signal generator is automatically configured
to that level.
In addition, you can define a level offset (for example to take external attenuation into
account). Note that the level offset is a purely mathematical value and does not change
the actual level of the signal at the RF output.
The level offset takes level offsets into account that occur before the signal has passed
through the DUT (usually an amplifier). For level offsets occurring after the DUT, define
a level offset in the "Amplitude" menu of the signal analyzer.
You can also define a Digital Attenuation that you can use for fast output level
changes.
NOTICE! Risk of damage to the DUT.
RMS levels that are too high can damage or destroy the DUT.
Make sure to keep an eye on the RMS level, especially when defining a level offset. A
level offset changes the displayed value of the RMS level, but not the real RMS level.
Displayed RMS level = real RMS level + level offset
Thus, the actual RMS level can be higher than the displayed level.
Configuration
Configuring Inputs and Outputs
Note: Always change the generator level from within the R&S FPS-K18 user interface
and thus synchronize the levels of both instruments.
If you change the generator level on the signal generator, the R&S FPS-K18 does not
synchronize the levels and measurement results are going to be invalid.
Remote command:
RMS level: CONFigure:GENerator:POWer:LEVel on page 235
CONFigure:GENerator:POWer:LEVel:LEDState? on page 236
Level offset: CONFigure:GENerator:POWer:LEVel:OFFSet on page 236
CONFigure:GENerator:POWer:LEVel:OFFSet:LEDState? on page 236
Maximum DUT Input Level
Defines the maximum level that the generated signal can have. Selecting a higher level
is not possible.
Defining a maximum output level is useful if you are measuring sensitive DUTs.
Remote command:
CONFigure:GENerator:DUT:INPut:MAXimum:POWer on page 231
CONFigure:GENerator:DUT:INPut:MAXimum:POWer:LEDState? on page 231
Attach to Analyzer Frequency
Turns synchronization of the analyzer and generator frequency on and off.
When you turn on this feature, changing the frequency on the analyzer automatically
adjusts the frequency on the generator.
Remote command:
CONFigure:GENerator:FREQuency:CENTer:SYNC[:STATe] on page 233
Center Frequency
Defines the frequency of the signal that the generator transmits.
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When you turn on Attach to Analyzer Frequency, any changes you make to the generator frequency are also adjusted on the analyzer.
Remote command:
CONFigure:GENerator:FREQuency:CENTer on page 232
CONFigure:GENerator:FREQuency:CENTer:LEDState? on page 233
Reference Frequency
Selects the source of the generator reference frequency.
The internal reference is that of the signal generator itself. When you select an external
reference, you can use another frequency reference, for example that of the R&S FPS.
Remote command:
CONFigure:GENerator:EXTernal:ROSCillator on page 232
CONFigure:GENerator:EXTernal:ROSCillator:LEDState? on page 232
Path RF / BB
Selects the RF signal path of the generator that is used for signal generation.
Remote command:
RF path: CONFigure:GENerator:TARGet:PATH:RF on page 239
BB path: CONFigure:GENerator:TARGet:PATH:BB? on page 238
Configuration
Configuring Inputs and Outputs
Segment
If you are using a waveform file that contains several different waveforms, you have to
select the segment to transfer to the signal generator.
Note that the segment that you have selected in the "Generator Setup" has to match
the segment selected for the reference signal, regarding the signal characteristics.
Remote command:
CONFigure:GENerator:SEGMent on page 237
CONFigure:GENerator:SEGMent:LEDState? on page 238
Digital Attenuation
Attenuates or amplifies the internal, digitally modulated I/Q signal on the signal generator. The level of the RF signal is thus adjusted accordingly.
Digital attenuation allows very fast level changes of the internal I/Q signals.
Note that digital attenuation only has an effect on the RF output level if the internal I/Q
modulator of the generator is active.
Remote command:
CONFigure:GENerator:POWer:LEVel:ATTenuation on page 235
RF Output
Turns the RF output on the connected signal generator on and off.
When you turn off the RF output, the generator does not feed a signal into the connec-
ted DUT.
Remote command:
CONFigure:GENerator:RFOutput[:STATe] on page 237
CONFigure:GENerator:RFOutput:LEDState? on page 237
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Settling Delay
The "Settling Delay" defines a time period between the time a parameter changes on
the generator and the start of the next measurement. The R&S FPS automatically
waits for the defined time period whenever one of the relevant generator settings has
been changed.
Defining a delay time is especially useful for measurements that automatically change
generator settings (for example the parameter sweep). The delay time considers the
settling time of the generator's hardware components between individual measurements.
Remote command:
CONFigure:DUT:STIMe on page 231
4.4.6 Reference: I/Q File Input
● Basics on Input from I/Q Data Files........................................................................ 55
● I/Q Data File Format (iq-tar)....................................................................................56
Configuration
Configuring Inputs and Outputs
4.4.6.1 Basics on Input from I/Q Data Files
The I/Q data to be evaluated in a particular R&S FPS application can not only be captured by the application itself, it can also be loaded from a file, provided it has the correct format. The file is then used as the input source for the application.
For example, you can capture I/Q data using the I/Q Analyzer application, store it to a
file, and then analyze the signal parameters for that data later using the Pulse application (if available).
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
As opposed to importing data from an I/Q data file using the import functions provided
by some R&S FPS applications, the data is not only stored temporarily in the capture
buffer, where it overwrites the current measurement data and is in turn overwritten by a
new measurement. Instead, the stored I/Q data remains available as input for any
number of subsequent measurements. Furthermore, the (temporary) data import
requires the current measurement settings in the current application to match the settings that were applied when the measurement results were stored (possibly in a different application). When the data is used as an input source, however, the data acquisition settings in the current application (attenuation, center frequency, measurement
bandwidth, sample rate) can be ignored. As a result, these settings cannot be changed
in the current application. Only the measurement time can be decreased, in order to
perform measurements on an extract of the available data (from the beginning of the
file) only.
When using input from an I/Q data file, the [RUN SINGLE] function starts a single measurement (i.e. analysis) of the stored I/Q data, while the [RUN CONT] function repeatedly analyzes the same data from the file.
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Sample iq.tar files
If you have the optional R&S FPS VSA application (R&S FPS-K70), some sample
iq.tar files are provided in the C:/R_S/Instr/user/vsa/DemoSignals directory
on the R&S FPS.
Pre-trigger and post-trigger samples
In applications that use pre-triggers or post-triggers, if no pre-trigger or post-trigger
samples are specified in the I/Q data file, or too few trigger samples are provided to
satisfy the requirements of the application, the missing pre- or post-trigger values are
filled up with zeros. Superfluous samples in the file are dropped, if necessary. For pretrigger samples, values are filled up or omitted at the beginning of the capture buffer,
for post-trigger samples, values are filled up or omitted at the end of the capture buffer.
4.4.6.2 I/Q Data File Format (iq-tar)
I/Q data is packed in a file with the extension .iq.tar. An iq-tar file contains I/Q
data in binary format together with meta information that describes the nature and the
source of data, e.g. the sample rate. The objective of the iq-tar file format is to separate I/Q data from the meta information while still having both inside one file. In addition, the file format allows you to include user-specific data and to preview the I/Q data
in a web browser (not supported by all web browsers).
Configuration
Configuring Inputs and Outputs
The iq-tar container packs several files into a single .tar archive file. Files in .tar
format can be unpacked using standard archive tools (see http://en.wikipedia.org/wiki/
Comparison_of_file_archivers) available for most operating systems. The advantage
of .tar files is that the archived files inside the .tar file are not changed (not compressed) and thus it is possible to read the I/Q data directly within the archive without
the need to unpack (untar) the .tar file first.
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
Contained files
An iq-tar file must contain the following files:
●
I/Q parameter XML file, e.g. xyz.xml
Contains meta information about the I/Q data (e.g. sample rate). The filename can
be defined freely, but there must be only one single I/Q parameter XML file inside
an iq-tar file.
●
I/Q data binary file, e.g. xyz.complex.float32
Contains the binary I/Q data of all channels. There must be only one single I/Q
data binary file inside an iq-tar file.
Optionally, an iq-tar file can contain the following file:
●
I/Q preview XSLT file, e.g. open_IqTar_xml_file_in_web_browser.xslt
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Contains a stylesheet to display the I/Q parameter XML file and a preview of the
I/Q data in a web browser (not supported by all web browsers).
A sample stylesheet is available at http://www.rohde-schwarz.com/file/
open_IqTar_xml_file_in_web_browser.xslt.
● I/Q Parameter XML File Specification.....................................................................57
● I/Q Data Binary File.................................................................................................62
I/Q Parameter XML File Specification
The content of the I/Q parameter XML file must comply with the XML schema
RsIqTar.xsd available at: http://www.rohde-schwarz.com/file/RsIqTar.xsd.
In particular, the order of the XML elements must be respected, i.e. iq-tar uses an
"ordered XML schema". For your own implementation of the iq-tar file format make
sure to validate your XML file against the given schema.
The following example shows an I/Q parameter XML file. The XML elements and attributes are explained in the following sections.
Configuration
Configuring Inputs and Outputs
Sample I/Q parameter XML file: xyz.xml
<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl"
href="open_IqTar_xml_file_in_web_browser.xslt"?>
<RS_IQ_TAR_FileFormat fileFormatVersion="1"
xsi:noNamespaceSchemaLocation="RsIqTar.xsd"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<Name>R&S FPS</Name>
<Comment>Here is a comment</Comment>
<DateTime>2011-01-24T14:02:49</DateTime>
<Samples>68751</Samples>
<Clock unit="Hz">6.5e+006</Clock>
<Format>complex</Format>
<DataType>float32</DataType>
<ScalingFactor unit="V">1</ScalingFactor>
<NumberOfChannels>1</NumberOfChannels>
<DataFilename>xyz.complex.float32</DataFilename>
<UserData>
<UserDefinedElement>Example</UserDefinedElement>
</UserData>
<PreviewData>...</PreviewData>
</RS_IQ_TAR_FileFormat>
Minimum Data Elements
The following information is always provided by an iq-tar file export from the
R&S FPS. If not specified otherwise, it must be available in all iq-tar files used to
import data to the R&S FPS.
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Element Possible Values Description
RS_IQ_TAR_FileFormat - The root element of the XML file. It must
Name string Optional: describes the device or applica-
Comment string Optional: contains text that further
DateTime yyyy-mm-ddThh:mm:ss Contains the date and time of the creation
Ch<n>_Samples integer Contains the number of samples of the I/Q
Configuration
Configuring Inputs and Outputs
contain the attribute
fileFormatVersion that contains the
number of the file format definition.
tion that created the file.
describes the contents of the file.
of the file. Its type is xs:dateTime (see
RsIqTar.xsd).
data. For multi-channel signals all channels have the same number of samples.
One sample can be:
●
A complex number represented as a
pair of I and Q values
●
A complex number represented as a
pair of magnitude and phase values
●
A real number represented as a single real value
See also Format element.
Ch<n>_Clock[Hz] double Contains the clock frequency in Hz, i.e. the
sample rate of the I/Q data. A signal generator typically outputs the I/Q data at a
rate that equals the clock frequency. If the
I/Q data was captured with a signal analyzer, the signal analyzer used the clock
frequency as the sample rate. The attribute unit must be set to "Hz".
Format complex | real | polar
Specifies how the binary data is saved in
the I/Q data binary file (see
DataFilename element). Every sample
must be in the same format. The format
can be one of the following:
●
complex: Complex number in cartesian format, i.e. I and Q values interleaved. I and Q are unitless
●
real: Real number (unitless)
●
polar: Complex number in polar format, i.e. magnitude (unitless) and
phase (rad) values interleaved.
Requires DataType = float32 or
float64
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Element Possible Values Description
Configuration
Configuring Inputs and Outputs
DataType int8 | int16 | int32 | float32 |
float64
ScalingFactor double Optional: describes how the binary data
NumberOfChannels integer Optional: specifies the number of chan-
Specifies the binary format used for samples in the I/Q data binary file (see
DataFilename element and "I/Q Data
Binary File" on page 62). The following
data types are allowed:
●
int8: 8 bit signed integer data
●
int16: 16 bit signed integer data
●
int32: 32 bit signed integer data
●
float32: 32 bit floating point data
(IEEE 754)
●
float64: 64 bit floating point data
(IEEE 754)
can be transformed into values in the unit
Volt. The binary I/Q data itself has no unit.
To get an I/Q sample in the unit Volt the
saved samples have to be multiplied by
the value of the ScalingFactor. For
polar data only the magnitude value has to
be multiplied. For multi-channel signals the
ScalingFactor must be applied to all
channels.
The attribute unit must be set to "V".
The ScalingFactor must be > 0. If the
ScalingFactor element is not defined, a
value of 1 V is assumed.
nels, e.g. of a MIMO signal, contained in
the I/Q data binary file. For multi-channels,
the I/Q samples of the channels are
expected to be interleaved within the I/Q
data file (see "I/Q Data Binary File"
on page 62). If the NumberOfChannels
element is not defined, one channel is
assumed.
DataFilename It is recommended that the file-
name uses the following convention:
<xyz>.<Format>.<Channels>ch.<Type>
●
<xyz> = a valid Windows
file name
●
<Format> = complex,
polar or real (see Format
element)
●
<Channels> = Number of
channels (see
NumberOfChannels element)
●
<Type> = float32, float64,
int8, int16, int32 or int64
(see DataType element)
Contains the filename of the I/Q data
binary file that is part of the iq-tar file.
Examples:
●
xyz.complex.1ch.float32
●
xyz.polar.1ch.float64
●
xyz.real.1ch.int16
●
xyz.complex.16ch.int8
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Element Possible Values Description
UserData xml Optional: contains user, application or
PreviewData xml Optional: contains further XML elements
Example
Configuration
Configuring Inputs and Outputs
device-specific XML data which is not part
of the iq-tar specification. This element
can be used to store additional information, e.g. the hardware configuration. User
data must be valid XML content.
that provide a preview of the I/Q data. The
preview data is determined by the routine
that saves an iq-tar file (e.g. R&S FPS).
For the definition of this element refer to
the RsIqTar.xsd schema. Note that the
preview can be only displayed by current
web browsers that have JavaScript
enabled and if the XSLT stylesheet
open_IqTar_xml_file_in_web_browser.xslt
is available.
The following example demonstrates the XML description inside the iq-tar file. Note
that this preview is not supported by all web browsers.
Open the xml file in a web browser, e.g. Microsoft Internet Explorer. If the stylesheet
open_IqTar_xml_file_in_web_browser.xslt is in the same directory, the web
browser displays the xml file in a readable format.
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Configuration
Configuring Inputs and Outputs
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<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="open_IqTar_xml_file_in_web_browser.xslt"?>
<RS_IQ_TAR_FileFormat fileFormatVersion="1" xsi:noNamespaceSchemaLocation=
"http://www.rohde-schwarz.com/file/RsIqTar.xsd" xmlns:xsi=
"http://www.w3.org/2001/XMLSchema-instance">
<Name>VSE_1.10a 29 Beta</Name>
<Comment></Comment>
<DateTime>2015-02-19T15:24:58</DateTime>
<Samples>1301</Samples>
<Clock unit="Hz">32000000</Clock>
<Format>complex</Format>
<DataType>float32</DataType>
<ScalingFactor unit="V">1</ScalingFactor>
<NumberOfChannels>1</NumberOfChannels>
<DataFilename>File.complex.1ch.float32</DataFilename>
<UserData>
<RohdeSchwarz>
<DataImportExport_MandatoryData>
<ChannelNames>
<ChannelName>IQ Analyzer</ChannelName>
</ChannelNames>
<CenterFrequency unit="Hz">0</CenterFrequency>
</DataImportExport_MandatoryData>
<DataImportExport_OptionalData>
<Key name="Ch1_NumberOfPostSamples">150</Key>
<Key name="Ch1_NumberOfPreSamples">150</Key>
</DataImportExport_OptionalData>
</RohdeSchwarz>
</UserData>
</RS_IQ_TAR_FileFormat>
Configuration
Configuring Inputs and Outputs
Example: ScalingFactor
Data stored as int16 and a desired full scale voltage of 1 V
ScalingFactor = 1 V / maximum int16 value = 1 V / 215 = 3.0517578125e-5 V
Scaling Factor Numerical value Numerical value x ScalingFac-
tor
Minimum (negative) int16 value
Maximum (positive) int16 value
- 215 = - 32768
215-1= 32767
-1 V
0.999969482421875 V
I/Q Data Binary File
The I/Q data is saved in binary format according to the format and data type specified
in the XML file (see Format element and DataType element). To allow reading and
writing of streamed I/Q data, all data is interleaved, i.e. complex values are interleaved
pairs of I and Q values and multi-channel signals contain interleaved (complex) sam-
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ples for channel 0, channel 1, channel 2 etc. If the NumberOfChannels element is not
defined, one channel is presumed.
Example: Element order for real data (1 channel)
I[0], // Real sample 0
I[1], // Real sample 1
I[2], // Real sample 2
...
Example: Element order for complex cartesian data (1 channel)
I[0], Q[0], // Real and imaginary part of complex sample 0
I[1], Q[1], // Real and imaginary part of complex sample 1
I[2], Q[2], // Real and imaginary part of complex sample 2
...
Example: Element order for complex polar data (1 channel)
Mag[0], Phi[0], // Magnitude and phase part of complex sample 0
Mag[1], Phi[1], // Magnitude and phase part of complex sample 1
Mag[2], Phi[2], // Magnitude and phase part of complex sample 2
...
Configuration
Configuring Inputs and Outputs
Example: Element order for complex cartesian data (3 channels)
Complex data: I[channel no][time index], Q[channel no][time index]
I[0][0], Q[0][0], // Channel 0, Complex sample 0
I[1][0], Q[1][0], // Channel 1, Complex sample 0
I[2][0], Q[2][0], // Channel 2, Complex sample 0
I[0][1], Q[0][1], // Channel 0, Complex sample 1
I[1][1], Q[1][1], // Channel 1, Complex sample 1
I[2][1], Q[2][1], // Channel 2, Complex sample 1
I[0][2], Q[0][2], // Channel 0, Complex sample 2
I[1][2], Q[1][2], // Channel 1, Complex sample 2
I[2][2], Q[2][2], // Channel 2, Complex sample 2
...
Example: Element order for complex cartesian data (1 channel)
This example demonstrates how to store complex cartesian data in float32 format
using MATLAB®.
% Save vector of complex cartesian I/Q data, i.e. iqiqiq...
N = 100
iq = randn(1,N)+1j*randn(1,N)
fid = fopen('xyz.complex.float32','w');
for k=1:length(iq)
fwrite(fid,single(real(iq(k))),'float32');
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fwrite(fid,single(imag(iq(k))),'float32');
end
fclose(fid)
Example: PreviewData in XML
<PreviewData>
<ArrayOfChannel length="1">
<Channel>
<PowerVsTime>
<Min>
<ArrayOfFloat length="256">
<float>-134</float>
<float>-142</float>
...
<float>-140</float>
</ArrayOfFloat>
</Min>
<Max>
<ArrayOfFloat length="256">
<float>-70</float>
<float>-71</float>
...
<float>-69</float>
</ArrayOfFloat>
</Max>
</PowerVsTime>
<Spectrum>
<Min>
<ArrayOfFloat length="256">
<float>-133</float>
<float>-111</float>
...
<float>-111</float>
</ArrayOfFloat>
</Min>
<Max>
<ArrayOfFloat length="256">
<float>-67</float>
<float>-69</float>
...
<float>-70</float>
<float>-69</float>
</ArrayOfFloat>
</Max>
</Spectrum>
<IQ>
<Histogram width="64" height="64">0123456789...0</Histogram>
</IQ>
</Channel>
Configuration
Configuring Inputs and Outputs
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</ArrayOfChannel>
</PreviewData>
4.5 Triggering Measurements
Access: "Overview" > "Trigger"
The R&S FPS-K18 provides functionality to trigger measurements.
The "Trigger" dialog box contains settings to configure triggered measurements.
The following trigger sources are supported:
●
Free Run
●
External
●
I/Q Power
●
IF Power
●
RF Power
Configuration
Configuring the Data Capture
The trigger settings are similar to those in the spectrum application. For a comprehensive description of the trigger functionality, refer to the R&S FPS user manual.
4.6 Configuring the Data Capture
Access: "Overview" > "Data Acquisition"
The "Data Acquisition" dialog box contains settings to configure the process of how the
application records the signal.
The remote commands required to configure the data capture are described in Chap-
ter 6.6.6, "Configuring the Data Capture", on page 239.
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Configuring the measurement bandwidth..................................................................... 66
└ Automatic adjustment..................................................................................... 66
└ Manual definition.............................................................................................66
└ Maximum bandwidth.......................................................................................66
Configuring the measurement time...............................................................................67
└ Automatic adjustment..................................................................................... 67
└ Manual definition.............................................................................................67
Inverting the I/Q branches.............................................................................................68
Defining the resolution bandwidth for spectrum measurements................................... 68
Configuring the measurement bandwidth
The sample rate defined for data acquisition is the sample rate with which the analyzer
samples the amplified signal.
The measurement bandwidth defines the flat, usable bandwidth of the final I/Q data.
The application allows you to adjust both values automatically or manually.
Automatic adjustment ← Configuring the measurement bandwidth
When you select automatic adjustment of sample rate and measurement bandwidth,
the application selects a bandwidth that is appropriate for the characteristics of the reference signal and adjusts the sample rate accordingly.
For more information about the reference signal, see Chapter 4.3, "Designing a Refer-
ence Signal", on page 35.
Remote command:
Mode: TRACe:IQ:SRATe:AUTO on page 243
Configuration
Configuring the Data Capture
Manual definition ← Configuring the measurement bandwidth
When you define the sample rate and measurement bandwidth manually, you can
select values that you are comfortable with. Because the bandwidth is a function of the
sample rate (and vice versa), the application adjusts the values when you change
either setting.
The following dependencies apply:
●
When you change the sample rate, the application updates the bandwidth accordingly (and vice versa). It also adjusts the capture length to the new values. The
capture time remains the same.
●
When you change the capture time or capture length, the sample rate and bandwidth remain the same.
Remote command:
Sample Rate: TRACe:IQ:SRATe on page 242
Bandwidth: TRACe:IQ:BWIDth on page 242
Maximum bandwidth ← Configuring the measurement bandwidth
The maximum bandwidth you can use depends on your hardware configuration.
For an overview of available bandwidth extensions, refer to the datasheet.
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By default, the application automatically determines the maximum bandwidth. When
you select a maximum bandwidth other than "Auto", the bandwidth is restricted to that
value. When you select the maximum bandwidth manually, make sure that this bandwidth is suited for the signal you are testing. Otherwise, the signal can be distorted and
results are no longer valid.
If you have no bandwidth extension this setting is not available.
For more information about the maximum bandwidth, refer to the user manual of the
R&S FPS I/Q Analyzer.
Remote command:
TRACe:IQ:WBANd[:STATe] on page 243
TRACe:IQ:WBANd:MBWidth on page 243
Configuring the measurement time
The measurement time (or capture time) defines the duration of a measurement in
which the required number of samples is collected.
The capture length is the number of samples that are captured during the selected
measurement time. The capture length is a function of the sample rate and the capture
time.
Configuration
Configuring the Data Capture
Automatic adjustment ← Configuring the measurement time
When you select automatic adjustment of capture time, the application selects a capture time that is appropriate for the characteristics of the reference signal.
As orientation, the application shows the length of the reference signal in the corresponding field in the dialog box (➙ "Ref Signal Duration").
For more information about the reference signal, see Chapter 4.3, "Designing a Refer-
ence Signal", on page 35.
Remote command:
Mode: [SENSe:]SWEep:TIME:AUTO on page 242
Reference signal: [SENSe:]REFSig:TIME? on page 240
Manual definition ← Configuring the measurement time
When you define the capture length and time manually, you can select values that you
are comfortable with.
However, make sure to define a capture time that is greater than the length of the reference signal - otherwise the application is not able to analyze the signal correctly.
The following dependencies apply:
●
When you change the capture time, the application updates the capture length
accordingly (and vice versa). Sample rate and bandwidth remain the same.
●
When you change the sample rate or bandwidth, the application updates the cap-
ture length accordingly. The capture time remains the same.
Note that the maximum capture time depends on the current measurement bandwidth.
Remote command:
Time: [SENSe:]SWEep:TIME on page 241
Capture length: [SENSe:]SWEep:LENGth on page 241
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Inverting the I/Q branches
The application allows you to swap the I and Q branches of the signal.
Swapping the branches is useful, for example, when the DUT inverts the real (I) and
imaginary (Q) parts of the signal and transfers the signal that way.
Note that the sideband is also inverted when you turn on this feature.
Remote command:
[SENSe:]SWAPiq on page 241
Defining the resolution bandwidth for spectrum measurements
The resolution bandwidth (RBW) defines the bandwidth of the resolution filter applied
to spectrum measurements (like the Spectrum FFT result).
The "RBW Mode" selects whether the application automatically selects a suitable resolution bandwidth based on the signal you are measuring, or if you define the resolution
bandwidth manually. When you select manual definition of the RBW (for example when
you want to do a measurement according to a certain telecommunications standard),
you can enter the bandwidth in the "RBW" field.
The amplifier measurement application supports any bandwidth between 1 Hz and
10 MHz.
Configuration
Sweep Configuration
Remote command:
[SENSe:]BANDwidth[:RESolution]:AUTO on page 240
[SENSe:]BANDwidth[:RESolution] on page 240
4.7 Sweep Configuration
Access: "Overview" > "Data Acquisition" > "Sweep"
The "Sweep" dialog box contains settings to configure the characteristics of a single
data recording (a sweep).
The remote commands required to configure the sweep are described in Chap-
ter 6.6.7, "Sweep Configuration", on page 244.
Averaging the I/Q data.................................................................................................. 68
Averaging the I/Q data
Averaging the I/Q data over several data captures can be a useful feature, for example
to suppress noise.
Noise suppression is useful in various cases, for example:
●
To improve the display of effects like non-linearities or the frequency response.
●
To improve the quality of DPD calculation.
●
To improve the quality of equalizer training.
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When you turn on averaging ("Enable I/Q Averaging"), you can define the number of
single data captures the application uses to average the data ("Average Count"). The
amount of data captured during a single data capture is defined by the capture length.
By default, the average is reset when the number of single data captures defined by
the average count is done.
Example:
When you define an average count of 10, the R&S FPS captures the signal 10 times
and then calculates the average over those 10 captures. After that, it resets the results,
captures the signal again 10 times and calculates the average etc.
A "Moving Average" on the other hand does not reset the results when the average
count is through. Instead, it continues to average the data. The moving average setting
only has an effect in continuous sweep mode.
Note that the moving average is automatically disabled during direct DPD calculation.
I/Q averaging is only possible for synchronized parts of the captured signal, because it
only makes sense if the same samples in the I/Q data stream are averaged. Therefore,
make sure that the measurement is synchronized. Otherwise, the results would be
invalid.
Remote command:
State: [SENSe:]SWEep:IQAVg[:STATe] on page 245
Count: [SENSe:]SWEep:IQAVg:COUNt on page 244
Moving average: [SENSe:]SWEep:IQAVg:MAVerage[:STATe] on page 245
Configuration
Synchronizing Measurement Data
4.8 Synchronizing Measurement Data
Access: "Overview" > "Sync / Error Est / Comp" > "Sync and Eval Range" > "Synchro-
nization"
The application allows you to synchronize the measured signal with the reference signal and provides various features to control synchronization.
Synchronization consists of signal estimation and compensation. After the application
has detected the position of the reference signal in the capture buffer, it estimates possible errors in the measured signal (for example the sample error rate or the amplitude
droop) by comparing it to the reference signal. The estimated errors can optionally be
compensated for.
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Configuration
Synchronizing Measurement Data
The remote commands required to configure signal synchronization are described in
Chapter 6.6.8, "Synchronizing Measurement Data", on page 246.
Turning synchronization of reference and measured signal on and off.........................70
Selecting the synchronization method.......................................................................... 71
Defining a synchronization confidence level................................................................. 71
Defining the estimation range....................................................................................... 71
Turning synchronization of reference and measured signal on and off
During measurements, the application tries to synchronize the measured signal with
the reference signal. When no significant correlation between the measured and reference signal can be found, synchronization fails.
However, you can turn off synchronization if you would like to run unsynchronized
measurements. Note however, that the calculation of some results in the result summary requires synchronization. These results cannot be calculated when you turn off
synchronization.
When you turn off synchronization, the results are always calculated over the complete
capture buffer. When synchronization is on, the results are always calculated over the
synchronized data range of the capture buffer. Therefore, the result values can be different for unsynchronized measurements, even if you measure the same signal (the
result is still valid and correct, though).
Failed synchronization
When you turn on "Stop on Sync Failed", the application automatically aborts the measurement, in case synchronization fails.
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Remote command:
CONFigure:SYNC:STAT on page 248
CONFigure:SYNC:SOFail on page 248
Selecting the synchronization method
The application allows you to select the method with which the application synchronizes the signals with the "Synchronization Mode" parameter. The following methods are
available.
●
I/Q Direct
The I/Q data for the reference signal is directly correlated with the reference and
measured signal. The performance of this method degrades in the presence of a
frequency offset between the measured and reference signals.
●
I/Q Phase Difference
Correlation on the phase differentiated I/Q data. This method retains phase change
information and can handle a frequency offset , but is more sensitive to noise than
the "I/Q Direct" method.
●
I/Q Magnitude
Correlation on the magnitude of the I/Q data with no regard for phase information.
This method can handle a frequency offset and is less sensitive to noise that the
"I/Q Phase Difference" method, but is only useful with amplitude modulated sig-
nals.
●
Trigger
It is assumed that the capture is triggered at the start of the reference waveform.
Only minimal correlation is performed to account for trigger jitter. This method is the
fastest synchronization method.
Remote command:
CONFigure:SYNC:DOMain on page 248
Configuration
Synchronizing Measurement Data
Defining a synchronization confidence level
The synchronization confidence level ("Sync Confidence") is a percentage that
describes how similar (or correlated) reference and measured signal need to be in
order for synchronization to be successful.
A value of 0 % means that synchronization is always successful even if the signals are
not correlated at all. However, results that rely on a good synchronization (like the
EVM) do contain reasonable values in that case. A value of 100 % means that the signals are identical (in that they are linearly dependent).
The cross-correlation is calculated over all samples in the capture buffer (or the estimation range, if you have defined one).
When the cross-correlation coefficient falls below the confidence level you have
defined, synchronization is no longer successful.
Remote command:
CONFigure:SYNC:CONFidence on page 247
Defining the estimation range
The estimation range has several effects on the synchronization process.
●
It defines which part of the reference signal is used for cross-correlation within the
capture buffer in order to align the reference and measured signals.
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●
It defines which part of the reference signal is used for error estimation.
By default, the application estimates over the complete reference signal. However, you
can also estimate over a given range in the capture buffer only. In that case, turn off
the "Use Full Ref Signal" feature. When you are not using the full reference signal, the
"Eval Start" and "Eval Stop" fields become available. The allowed values are offsets
relative to the beginning of the capture buffer (0 s). The highest offset possible
depends on the size of the capture buffer.
Defining an estimation range is useful in the following cases.
●
If you want to limit the estimation to a specific part of the signal, for example if the
signal contains a preamble or midamble.
●
If you want to limit the estimation to the ON part of a TDD signal.
●
If you want to increase the measurement speed for relatively long signals, for
example an LTE signal.
On the downside, limiting the estimation range leads to a higher empirical variance of
the results.
In the preview pane displayed in the dialog box, the currently defined estimation range
is represented by two red vertical lines.
Tip: You can also use the touchscreen to move the lines to a new position in the pre-
view pane. However, this way is not as accurate as entering a number into the input
field.
Remote command:
CONFigure:ESTimation:FULL on page 246
CONFigure:ESTimation:STARt on page 247
CONFigure:ESTimation:STOP on page 247
Configuration
Evaluating Measurement Data
4.9 Evaluating Measurement Data
Access: "Overview" > "Sync / Error Est / Comp" > "Sync and Eval Range" > "Eval
Range"
The application allows you to define the time frame in the reference signal used to
evaluate and calculate the measurement results.
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The remote commands required to configure signal evaluation are described in Chap-
ter 6.6.9, "Defining the Evaluation Range", on page 249.
Configuration
Evaluating Measurement Data
Defining the evaluation range....................................................................................... 73
Defining the evaluation range
The evaluation range defines the data range in the capture buffer over which the application calculates the measurement results.
By default, the application calculates the results over the complete capture buffer. If
synchronization has been successful, the application calculates the results over the
capture buffer range in which the reference signal has been found. If you have turned
off synchronization or if it has not been successful, the complete capture buffer is used
to calculate the remaining results.
Example:
The capture buffer is 30 ms long, the reference signal starts at 9 ms and is 10 ms long.
When synchronization is successful, the evaluation range starts at 9 ms and ends at
19 ms. If synchronization has been turned off, the evaluation range is the full capture
buffer.
However, you can also select a particular data range within the reference signal. In that
case, turn off the "Use Full Ref Signal" feature. When it is off, the "Eval Start" and "Eval
Stop" fields become available. The allowed values are offsets relative to the beginning
of the reference signal (0 s). The highest offset possible depends on the length of the
reference signal.
Example:
The situation is as described above (30 ms capture buffer, 10 ms reference signal).
Let's say you want to evaluate milliseconds 2 to 6 of the reference signal. In that case,
you would have to define a start offset of 11 ms (the reference signal starts at 9 ms,
plus the first 2 ms you are not interested in = 11 ms) and a stop offset of 15 ms (9 ms
+ 6 ms).
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In the preview pane displayed in the dialog box, the currently defined evaluation range
is represented by two blue vertical lines.
Tip: You can also use the touchscreen to move the lines to a new position in the preview pane. However, this way is not as accurate as entering a number into the input
field.
Remote command:
CONFigure:EVALuation:FULL on page 249
CONFigure:EVALuation:STARt on page 250
CONFigure:EVALuation:STOP on page 250
4.10 Estimating and Compensating Signal Errors
Access: "Overview" > "Sync / Error Est / Comp" > "Error Est / Compensation"
The application allows you to estimate possible undesired effects in the signal, and, if
there are any, also compensate these effects.
Configuration
Estimating and Compensating Signal Errors
The remote commands required to configure error compensation and equalization are
described in Chapter 6.6.10, "Estimating and Compensating Signal Errors",
on page 251.
Estimation and compensation
When you turn on error estimation only, the results are not compensated for the corresponding errors.
When you turn on error compensation, the displayed results are also corrected by the
estimated errors. Note that in that case, the signal might look better than it actually is.
Compensation without estimation is not possible.
Generally, it is recommended to switch off the estimation of a certain parameter if it is
not existent. E.g., if generator and analyzer are frequency locked, it is recommended to
switch off the frequency error estimation. Furthermore sample rate error estimation can
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be switched off if the frequency locked generator is a vector signal generator, i.e.
includes the DAC.
You can estimate and compensate the following effects:
●
I/Q Imbalance: combined effect of amplitude and phase error.
●
I/Q Offset: shift of the constellation points in a particular direction.
●
Frequency Error: difference between measured and reference center frequency.
●
Amplitude Droop: decrease of the signal power over time in the transmitter.
●
Sample Error Rate: difference between the sample rate of the reference signal
and the measured signal.
4.11 Equalizer
In addition, the amplifier application provides equalizer functionality. The equalizer corrects distortions in the frequency characteristics during the transmission of the signal. It
can thus help to faithfully reproduce the input signal at the amplifier output.
Configuration
Equalizer
Using the equalizer
Using the equalizer requires a description of the equalizer filter. You can either train
(and save) such a filter automatically with the R&S FPS, or use one that you already
have.
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Training (or creating) the equalizer filter is a process in which the R&S FPS compares
the frequency response of the input and output signal and equalizes potential distortion. The goal is to match the frequency response of the output signal and the input
signal. The R&S FPS is able to train the filter based on all samples in the evaluation
range.
The "Equalizer Filter Length For Training" property defines the number of FIR filter
coefficients to be calculated. A larger number of samples generally yields better
results, but takes longer to calculate. After you have defined the filter length (coefficients), you can start the training sequence with the "Train Equalizer Filter on Current
I/Q Data" feature. To apply the filter, turn on the equalizer with the "Equalizer State"
toggle.
Note that the reference and measured signal need to be synchronized for a successful
filter training. Make sure to turn on signal synchronization before you train a filter.
When the filter training is done, you can save the filter in a csv or a fres file (➙ "Save
Equalizer").
For more information about the fres file format, refer to the R&S FPS user manual.
If you want to use an equalizer filter that you already have from a previous measure-
ment, you can restore that filter (➙ "Load Equalizer Filter") and apply it without a training sequence.
The dialog box also shows the information about the filter file that is currently in use.
This information includes the file name, the date it was modified last and the length of
the filter (in samples).
Note: Any equalizer filter is only valid for the sample rate it has been trained for.
If you change the sample rate when an equalizer filter is active, the R&S FPS automatically turns off the equalizer filter. If you still want to use an equalizer filter with the new
sample rate, you have to train and apply the equalizer filter again.
Note: An I/Q data export always exports the unequalized (raw) data.
If you want to export the equalized data, you can do so with the following SCPI command.
TRACe:IQ:EQUalized? on page 207
Configuration
Applying System Models
Remote command:
Filter length: CONFigure:EQUalizer:FILTer:LENGth on page 254
Start training: CONFigure:EQUalizer:TRAin on page 255
Store filter: MMEMory:STORe:EQUalizer:FILTer:COEFficient on page 256
File format: CONFigure:EQUalizer:FILTer:FILE:FORMat on page 254
Restore filter: MMEMory:LOAD:EQUalizer:FILTer:COEFficient on page 255
Equalizer state: CONFigure:EQUalizer[:STATe] on page 255
Manual filter definition: CONFigure:EQUalizer:FPARameters on page 254
4.12 Applying System Models
Access: "Overview" > "Measurement" > "Modeling"
A polynomial model describes the characteristics of the DUT based on the input signal
and the output signal of the amplifier.
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The remote commands required to configure system models are described in Chap-
ter 6.6.11, "Applying a System Model", on page 256.
Turning system modeling on and off.............................................................................77
Selecting the degree of the polynomial.........................................................................78
Defining the modeling range......................................................................................... 78
Selecting the modeling scale........................................................................................ 79
Configuration
Applying System Models
Turning system modeling on and off
You can use the system modeling functionality to calculate a mathematical model that
describes the properties of the DUT.
Using a model is useful to observe and estimate the behavior of the amplifier and, if
necessary, adjust the DUT behavior. The application supports memory-free polynomial
models to the 18th degree.
The following diagrams contain traces that show the model. These traces are calculated by using the model function on the reference signal.
●
AM/AM
●
AM/PM
Note that the model traces are also the basis for the DPD functionality available in the
R&S FPS-K18.
When the characteristics of the modeled signal match those of the measured signal,
the model describes the DUT behavior well. If not, you can try to get a better result by
adjusting the model properties.
When you turn on modeling, the application shows an additional trace in the graphical
result displays. This trace corresponds to the signal characteristics after the model has
been applied to the reference signal.
Selecting the modeling sequence
The modeling sequence selects the sequence in which the models are calculated. The
application then either calculates the AM/AM model before calculating the AM/PM
model (default), or vice versa.
Remote command:
CONFigure:MODeling[:STATe] on page 258
CONFigure:MODeling:SEQuence on page 258
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Selecting the degree of the polynomial
In addition to the type of curve, you can also select the order of the polynomial model.
The order of the model defines the degree, complexity and number of terms in the pol-
ynomial model. In general, a polynomial of the Nth degree looks like this:
y = a0 + a1x + a2x2 + … + aNx
The degree of the model is defined by N (as an index or exponent). The higher the
order, the more complex the calculation and the longer it takes to calculate the model.
Higher models do not necessarily lead to better fitting model curves.
Note that the nonlinear effects consume an additional bandwidth proportional to 2
times the number of odd factors in the polynomial, excluding the linear one.
Example:
If the signal bandwidth is 1 MHz and the highest degree is 5, the bandwidth of the
resulting signal is increased by 2 times 2 (because there are the variables a3 and a5)
times 1 MHz which are 4 MHz. This leads to a total signal bandwidth of 5 MHz (1 MHz
+ 4 MHz). The configured recording bandwidth must be at least 5 MHz to record all
nonlinear effects generated by the DUT.
Tip: To select a specific subset of polynomial degrees you want to apply, you can
either:
●
Define a range of degrees (e.g. "0 - 5", in that case the application applies all
degrees in that range).
●
Define a set of individual degrees only (e.g. "1;3;5;7", in that case the application
applies those degrees only). Note that the "." key on the front panel draws the ";"
character.
●
Define a combination of the methods mentioned above (e.g. "1;3;5-7")
Configuration
Applying System Models
N
Remote command:
AM/AM: CONFigure:MODeling:AMAM:ORDer on page 256
AM/PM: CONFigure:MODeling:AMPM:ORDer on page 257
Defining the modeling range
The modeling range defines the part of the signal that the model is applied to.
When you limit the level range that the model is applied to, only samples with levels
between peak level and "peak level minus modeling level range value" are used during
the model calculation. Note that the modeling range is also the range the DPD is
applied to.
You can also define a smaller or larger modeling level range. Make sure, however, that
the range is large enough not to distort the model.
In addition, you can define the number of points on the curve that the application uses
to calculate the model. The selected points are spaced equidistant on a logarithmic
scale (an equidistant spacing on a linear scale is also possible if you prefer that). Using
fewer modeling points further speeds up measurement times (but can reduce the quality of the model if set too low).
Remote command:
Range: CONFigure:MODeling:LRANge on page 257
Points: CONFigure:MODeling:NPOints on page 257
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Selecting the modeling scale
The input power range is split into several equally spaced subranges (= modeling
points) for the calculation of the amplifier model.
With the "Modeling Scale", you can select whether the split is done on a logarithmic or
linear basis.
Remote command:
CONFigure:MODeling:SCALe on page 257
4.13 Applying Digital Predistortion
Access: "Overview" > "Measurement" > "DPD"
Digital predistortion (DPD) is a method to improve the linearity of an RF power amplifier. Basically, DPD is a set of correction values that is added to the input signal to
compensate the non-linearities that occur in the amplifier. The output signal measured
by the R&S FPS then shows the corrected amplifier characteristics.
Configuration
Applying Digital Predistortion
You can compensate non-linearities with the functionality of the amplifier application.
The application provides two compensation methods: polynomial DPD and direct DPD.
Note that you can only use one of the two DPD types at any time. When you turn on
the polynomial DPD, the R&S FPS automatically turns off the direct DPD and vice
versa.
Using the DPD functionality requires a connection to a signal generator. For more information about configuring generators, see Chapter 4.4.5, "Controlling a Signal Genera-
tor", on page 50.
Remote command:
CONFigure:DDPD[:STATe] on page 262
● Polynomial DPD......................................................................................................79
● Direct DPD (R&S FPS-K18D)................................................................................. 82
4.13.1 Polynomial DPD
For polynomial DPD, the application calculates the correction values based on a polynomial function, whose characteristics you can define with the settings available for the
system models. The polynomial DPD approach used by the R&S FPS compensates for
AM/AM (amplitude-to-amplitude) distortion and AM/PM (amplitude-to-phase) distortion.
When you apply the DPD, the correction values are applied to the input signal to
improve the linearity of the amplifier.
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Configuration
Applying Digital Predistortion
The remote commands required to configure the polynomial DPD are described in
Chapter 6.6.12, "Applying Digital Predistortion", on page 258.
Selecting the DPD method............................................................................................80
Selecting the DPD shaping method.............................................................................. 81
Selecting the order of model calculation....................................................................... 81
DPD Power / Linearity Tradeoff.....................................................................................82
Selecting the DPD method
The amplifier application provides a couple of DPD calculation methods.
●
"Use Generator DPD Option K541"
The signal generator corrects the input signal in real time.
This method requires a Rohde & Schwarz signal generator equipped with option
R&S SMx-K541.
The source of the predistortion values is either a table or a polynomial function.
After a successful measurement, you can apply the predistortion values that were
calculated by the R&S FPS with the "Update" button. (The button is only available
when data has been captured on the R&S FPS and synchronization was success-
ful).
Note that you have to turn on the DPD model in order to make the DPD work.
As long as you use the same amplifier, the polynomial DPD calculated with this
method is valid for all signals that use a similar bandwidth and frequency as the
signal it was calculated for.
●
"Generate Pre-Distorted Waveform File"
The R&S FPS applies the correction values taken from the table or polynomial
function to each measured sample and generates a waveform file that contains the
corrected input signal. For TDD and FDD signals, we recommend that you use the
full reference signal to generate the DPD.
You can start the DPD calculation and transfer the resulting waveform file to the
connected generator with the "Generate and Load" button. Successful calculation
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and transfer are indicated by a green LED. Note that you have to turn on the DPD
model in order to make the DPD work.
Note:
When you use this method, the predistortion information only applies to the cur-
rently selected reference signal and generator level. When you change the refer-
ence signal or generator level, you have to create a file that applies to the new ref-
erence signal.
You can also save the predistorted waveform into a waveform file with the "Store
Pre-Distorted Waveform File" feature for later reference.
Remote command:
CONFigure:DPD:METHod on page 265
Selecting the DPD shaping method
The application provides several ways for DPD calculation (or shaping).
●
"From Table"
Shapes the DPD function based on a table that contains the correction values
required to predistort the signal.
The calculation of the table is based on the AM/AM and AM/PM polynomial mod-
els.
For more information about the contents and usage of the shaping table, refer to
the documentation of the R&S SMW-K541.
You can define a file name for the DPD table in the corresponding field.
●
"From Polynomial"
Shapes the DPD function based on a correction polynomial that is calculated out of
the model polynomial.
Compared to DPD based on a shaping table, this method does not transfer a list
with correction values. Instead, the application transfers the polynomial coefficients
of the correction polynomial.
For more information, see Chapter 4.12, "Applying System Models", on page 76.
You can update the DPD shaping on the signal generator comfortably with the
"Update" button.
Remote command:
Mode: CONFigure:DPD:SHAPing:MODE on page 266
Table name: CONFigure:DPD:FNAMe on page 265
Configuration
Applying Digital Predistortion
Selecting the order of model calculation
The application allows you to compensate for AM/AM distortion, AM/PM distortion or
both simultaneously. You can turn correction of the distortion models on and off in the
corresponding fields.
If you want to predistort both the AM/AM distortion and the AM/PM distortion simultaneously, you can select the order in which the curves are calculated and applied to the
I/Q signal on the R&S SMW.
●
AM/AM First
Calculates the AM/AM first, then calculates the AM/PM based on the signal that
has already been corrected by its AM/AM distortions.
●
AM/PM First
Calculates the AM/PM first, then calculates the AM/AM based on the signal that
has already been corrected by its AM/PM distortions.
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Note: the DPD sequence is displayed by the diagram that is part of the dialog box.
Remote command:
AM/AM state: CONFigure:DPD:AMAM[:STATe] on page 262
AM/PM state: CONFigure:DPD:AMPM[:STATe] on page 263
Both: CONFigure:DPD:AMXM[:STATe] on page 263
Calculation order: CONFigure:DPD:SEQuence on page 266
DPD Power / Linearity Tradeoff
The "DPD Power / Linearity Tradeoff" describes the effects of the DPD on the amplifier
characteristics.
When you define a tradeoff of 0 %, the DPD aims for the best linearity (green line in
the illustration below). When you increase the tradeoff value, the DPD aims for an optimization of the output power at the expense of linearity. In the 100 % case, output
power is maximized, whereas linearity is reduced compared to all other cases. The
blue line shows the default tradeoff value of 50 %.
Configuration
Applying Digital Predistortion
Remote command:
Polynomial DPD: CONFigure:DPD:TRADeoff on page 266
Direct DPD: CONFigure:DDPD:TRADeoff on page 262
4.13.2 Direct DPD (R&S FPS-K18D)
The direct DPD is an iterative process in which the correction values are determined
for each sample of the input signal. Compared to the polynomial DPD, the direct DPD
is not based on a model. It rather calculates the correction values for each sample
directly.
Determining the DPD directly is based on a sequence of individual measurements (iterations). When one iteration is done, the R&S FPS applies the correction values, measures the improved input signal again, applies the correction values etc. This process
goes on until the number of iterations you have defined is done. Usually, the predistortion gets better with an increasing number of iterations. On the other hand, increasing
the number of iterations also increases the measurement time.
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Note that synchronization must be successful in every iteration to get a DPD. The
R&S FPS repeats every iteration up to 10 times if synchronization fails. If synchronization was not possible 10 times in a row, the R&S FPS stops the generation of the direct
DPD and shows a corresponding message. Reducing the synchronization confidence
level can help in that case.
The result of the direct DPD is an I/Q file that contains a predistorted waveform. When
you save the I/Q file, you can later play it back on a signal generator.
For TDD and FDD signals, we recommend that you use the full reference signal to
generate the DPD.
Further improvement of predistortion
In addition to increasing the number of iterations, it is recommended to apply signal
averaging during each iteration. Averaging helps to remove noise from the signal,
which in turn improves the quality of the predistortion values.
Without averaging, each iteration consists of a single measurement. When you apply
averaging, the number of measurements during each iteration increases, depending on
the number of averages you have defined.
Configuration
Applying Digital Predistortion
The advantage of the direct DPD compared to the polynomial DPD is, that it takes
memory effects into account. This, and the fact that it is not based on a model, but corrects each sample individually, makes the direct DPD the superior method to predistort
the input signal and determine the ideal DPD effect for your DUT. Note however, that
the correction values that have been determined are only applicable to the signal and
amplifier you have used. If the signal characteristics change in any way, you have to
predistort the signal again.
The direct DPD is especially useful for the following test cases.
●
Determining the best performance of a DUT.
●
Removing external effects from the measurement results, for example a preampli-
fier that should not be considered in the final measurement results.
Moving averages during direct DPD calculation
The moving average is automatically disabled during the direct DPD calculation.
Generator control during direct DPD calculation
When direct DPD is activated, the generator will be prevented from changing its
attenuator setting automatically, i.e. it’s being set into mode "Fixed" if it was in "Auto"
mode so far. The attenuator mode will be switched back to "Auto" when direct DPD is
turned off. If the generator was in "Fixed" or "Manual" mode, the mode is not changed.
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Configuration
Applying Digital Predistortion
The remote commands required to configure the direct DPD are described in Chap-
ter 6.6.12, "Applying Digital Predistortion", on page 258.
Functions available for the direct DPD described elsewhere:
●
"DPD Power / Linearity Tradeoff" on page 82
Running a direct DPD sequence...................................................................................84
Running a direct DPD sequence
The direct DPD method requires one or more measurements (or iterations) to determine the correction values.
When you select the "Start Direct DPD Sequence" button, the R&S FPS initiates a
sequence of measurements during which the DPD is calculated. The number of measurements performed during the sequence depends on the number of "Iterations" you
have defined. It is also recommended to average each iteration for further improvement of the quality of the input signal. The "Gain Expansion" defines the increase of
input power relative to the peak power value of the reference signal.
You can follow the process of the DPD sequence in the channel bar. The "DPD Count"
label shows the current iteration and the complete number of iterations of the DPD
sequence. If you are using averaging, the "Count" label shows the process of the current iteration. The first number is the current measurement, the second number the
total number of measurements.
When the DPD sequence is done, the R&S FPS stores the predistorted I/Q signal in a
waveform file and transfers it to the signal generator. You can change the name of the
waveform file in the "DPD File Name on Generator" property. The waveform file is
transferred automatically to the generator. It is loaded into the ARB when you turn on
the "Apply Direct DPD" property. (Note that when you turn off the direct DPD again, the
generator restores the waveform file that was previously used.)
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You can also save the waveform file, for example if you want to use it again later, with
the "Store Predistorted Waveform File" property.
Note that you can stop a DPD sequence any time through the dialog box shown while
the DPD sequence is running.
●
"Finish": Stops the DPD sequence and keeps the predistorted I/Q data that have
already been calculated.
●
"Abort": Stops the DPD sequence and discards the predistorted I/Q data that have
already been calculated.
Remote command:
Iterations: CONFigure:DDPD:COUNt on page 260
Start sequence: CONFigure:DDPD:STARt on page 261
Gain expansion: CONFigure:DDPD:GEXPansion on page 261
File name: CONFigure:DDPD:FNAMe on page 261
Save DPD: MMEMory:STORe:DDPD on page 269
Apply DPD: CONFigure:DDPD:APPLy[:STATe] on page 259
Configuration
Configuring Power Measurements
4.14 Configuring Power Measurements
Access: "Overview" > "Measurement" > "Power Settings"
The Amplifier application features functionality to configure measurements that determine power characteristics of an amplifier.
The remote commands required to configure power measurements are described in
Chapter 6.6.14, "Configuring Power Measurements", on page 275.
Configuring compression point calculation....................................................................85
Configuring compression point calculation
The application evaluates three compression points. The compression points represent
the input power where the gain of the amplifier deviates by a certain amount from a
reference point on the gain curve. The amount of deviation is either 1 dB, 2 dB or 3 dB.
Because these compression points are relative values, you have to define the reference gain.
There are two ways to get the reference gain: automatically or manually.
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If you define the reference gain manually, the reference point is the gain at a certain
input power (which you can define in the "Reference Input Power" input field).
If you select automatic calculation of the reference gain, the reference gain is the
average gain that has been measured (the average gain is a result shown in the
Numeric Result Summary).
In the Gain Compression result display, the reference point is indicated by a red line.
Remote command:
Method: CONFigure:POWer:RESult:P3DB[:STATe] on page 275
Input power: CONFigure:POWer:RESult:P3DB:REFerence on page 275
4.15 Configuring Adjacent Channel Leakage Error (ACLR) Measurements
Access: "Overview" > "Measurement" > "ACLR Settings"
The application allows you to define the basic characteristics of the Tx channel and
neighboring channels when you perform ACLR measurements.
Configuration
Configuring Adjacent Channel Leakage Error (ACLR) Measurements
The remote commands required to configure the ACLR measurements are described
in Chapter 6.6.13, "Configuring ACLR Measurements", on page 269.
Number of channels: Tx , Adj .......................................................................................87
Selecting the measurement bandwidth.........................................................................87
Reference Channel ...................................................................................................... 87
Channel Bandwidth ......................................................................................................88
Channel Spacings ........................................................................................................88
Weighting Filters ...........................................................................................................89
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Number of channels: Tx , Adj
Up to 18 carrier channels and up to 12 adjacent channels can be defined.
Results are provided for the Tx channel and the number of defined adjacent channels
above and below the Tx channel. If more than one Tx channel is defined, the carrier
channel to which the relative adjacent-channel power values should be referenced
must be defined (see " Reference Channel " on page 87).
Remote command:
Number of Tx channels:
[SENSe:]POWer:ACHannel:TXCHannel:COUNt on page 275
Number of Adjacent channels:
[SENSe:]POWer:ACHannel:ACPairs on page 270
Selecting the measurement bandwidth
When you perform an ACLR measurement, it is important to select a measurement
bandwidth that is large enough to capture all channels you want to evaluate in the
ACLR measurement.
The application provides automatic adjustment of the measurement bandwidth to the
bandwidth occupied by all channels evaluated in the ACLR measurement. To do so,
turn on the "Auto Adjust Acquisition Bandwidth" function.
Note that you also have to turn on automatic bandwidth selection in the "Data Acquisition" dialog box in order to adjust the measurement bandwidth to the ACLR configuration.
If you define the bandwidth manually, make sure to take one that is large enough to
capture all channels. Otherwise, the R&S FPS does not evaluate measurement results.
Also make sure that the R&S FPS you are using can actually handle the bandwidth
occupied by the transmission and adjacent channels. For larger bandwidths, one of the
I/Q bandwidth extensions could be necessary (refer to the datasheet for a complete list
of available bandwidth extensions).
Remote command:
[SENSe:]POWer:ACHannel:AABW on page 270
Configuration
Configuring Adjacent Channel Leakage Error (ACLR) Measurements
Reference Channel
The measured power values in the adjacent channels can be displayed relative to the
transmission channel. If more than one Tx channel is defined, define which one is used
as a reference channel.
Tx Channel 1 Transmission channel 1 is used.
(Not available for MSR ACLR)
Min Power Tx Channel The transmission channel with the lowest power is used as a reference channel.
Max Power Tx Channel
Lowest & Highest
Channel
The transmission channel with the highest power is used as a reference channel
(Default).
The outer left-hand transmission channel is the reference channel for the lower
adjacent channels, the outer right-hand transmission channel that for the upper
adjacent channels.
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Remote command:
[SENSe:]POWer:ACHannel:REFerence:TXCHannel:MANual on page 273
[SENSe:]POWer:ACHannel:REFerence:TXCHannel:AUTO on page 273
Channel Bandwidth
The Tx channel bandwidth is normally defined by the transmission standard.
The value entered for any Tx channel is automatically also defined for all subsequent
Tx channels. Thus, only enter one value if all Tx channels have the same bandwidth.
The value entered for any ADJ or ALT channel is automatically also defined for all
alternate (ALT) channels. Thus, only enter one value if all adjacent channels have the
same bandwidth.
Remote command:
[SENSe:]POWer:ACHannel:BANDwidth[:CHANnel<ch>] on page 271
[SENSe:]POWer:ACHannel:BANDwidth:ACHannel on page 271
[SENSe:]POWer:ACHannel:BANDwidth:ALTernate<ch> on page 271
Channel Spacings
Channel spacings are normally defined by the transmission standard but can be
changed.
If the spacings are not equal, the channel distribution in relation to the center frequency
is as follows:
Configuration
Configuring Adjacent Channel Leakage Error (ACLR) Measurements
Odd number of Tx channels The middle Tx channel is centered to center frequency.
Even number of Tx channels The two Tx channels in the middle are used to calculate the fre-
quency between those two channels. This frequency is aligned to
the center frequency.
The spacings between all Tx channels can be defined individually. When you change
the spacing for one channel, the value is automatically also defined for all subsequent
Tx channels. This allows you to set up a system with equal Tx channel spacing quickly.
For different spacings, set up the channels from top to bottom.
Tx1-2 Spacing between the first and the second carrier
Tx2-3 Spacing between the second and the third carrier
… …
If you change the adjacent-channel spacing (ADJ), all higher adjacent channel spacings (ALT1, ALT2, …) are multiplied by the same factor (new spacing value/old spacing
value). Again, only enter one value for equal channel spacing. For different spacing,
configure the spacings from top to bottom.
Remote command:
[SENSe:]POWer:ACHannel:SPACing:CHANnel<ch> on page 274
[SENSe:]POWer:ACHannel:SPACing[:ACHannel] on page 274
[SENSe:]POWer:ACHannel:SPACing:ALTernate<ch> on page 274
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Weighting Filters
Weighting filters allow you to determine the influence of individual channels on the total
measurement result. For each channel you can activate or deactivate the use of the
weighting filter and define an individual weighting factor ( "Alpha:" value).
Remote command:
Activating/Deactivating:
[SENSe:]POWer:ACHannel:FILTer[:STATe]:CHANnel<ch> on page 273
[SENSe:]POWer:ACHannel:FILTer[:STATe]:ACHannel on page 272
[SENSe:]POWer:ACHannel:FILTer[:STATe]:ALTernate<ch> on page 273
Alpha value:
[SENSe:]POWer:ACHannel:FILTer:ALPHa:CHANnel<ch> on page 272
[SENSe:]POWer:ACHannel:FILTer:ALPHa:ACHannel on page 272
[SENSe:]POWer:ACHannel:FILTer:ALPHa:ALTernate<ch> on page 272
4.16 Configuring the Parameter Sweep
Configuration
Configuring the Parameter Sweep
Access: "Overview" > "Measurements" > "Meas Modes" > "Parameter Sweep"
The parameter sweep is a measurement that allows you to compare a result (that you
can select arbitrarily) against two other parameters. The advantage of the parameter
sweep is that it controls the signal generator and the analyzer, and automatically
changes the signal characteristics (for example the frequency) without you having to
do those changes manually. In addition, it combines the results in a single and well
arranged diagram and / or numerical result display (➙ Parameter Sweep).
Example:
In the default state, the application compares the EVM against the frequency and the
generator power.
In that case, the R&S FPS first performs a measurement on the first frequency for each
generator output level in the defined range. When this measurement is done, the
R&S FPS continues to measure all power levels on the second frequency and so on.
Frequency range: 10 MHz to 20 MHz, stepsize 1 MHz. Output level range: -10 dBm to
0 dBm, stepsize: 1 dB.
●
1st measurement: 10 MHz with a generator output level of -10 dBm.
●
(...)
●
11th measurement: 10 MHz with a generator output level of 0 dBm.
●
12th measurement: 11 MHz with a generator output level of -10 dBm.
●
(...)
●
22nd measurement: 11 MHz with a generator output level of 0 dBm.
●
(...)
●
nth measurement: 20 MHz with a generator output level of 0 dBm.
The configuration affects the number of measurements that will be performed. The
number of measurements in turn has an effect on the overall measurement time of the
parameter sweep.
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The parameter sweep requires a connection to a signal generator. For more information about configuring generators, see Chapter 4.4.5, "Controlling a Signal Generator",
on page 50.
Configuration
Configuring the Parameter Sweep
The remote commands required to configure the parameter sweep are described in
Chapter 6.6.15, "Configuring Parameter Sweeps", on page 276.
Turning the parameter sweep on and off...................................................................... 90
Selecting the data to be evaluated during the parameter sweep..................................90
Synchronizing the levels of signal generator and analyzer...........................................91
Turning the parameter sweep on and off
Before you can use the parameter sweep functionality, you have to turn it on deliberately.
When you turn it on, the R&S FPS starts the parameter sweep in single sweep mode
([Run Sgl] and [Run Cont] both start the parameter sweep in that case). When the
parameter sweep is on, other measurements are not possible, and vice versa.
Turning on the parameter sweep also expands the channel bar by several labels that
carry information about the progress of the parameter sweep.
Remote command:
CONFigure:PSWeep[:STATe] on page 277
Selecting the data to be evaluated during the parameter sweep
When you are performing a parameter sweep, you can compare an arbitrary result
against one or two arbitrary parameters.
Depending on your selection, the R&S FPS changes the values of the selected parameters on the signal generator during the measurement, and calculates the result for
each combination of values.
If there is more than one instance of the parameter sweep, the R&S FPS applies the
selected parameters to all instances. The displayed results on the other hand, can be
different for each instance.
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●
Center Frequency
Controls the frequency of the signal generator.
●
Generator Power
Controls the output power of the signal generator.
●
Envelope to RF Delay
Controls the delay between the envelope and the RF signal on the signal generator.
●
Envelope Bias
Controls the envelope bias on the signal generator.
You can define the scope of the measurement by adjusting the start and stop values
for both parameters, and assign a certain stepsize. Based on these values, the
R&S FPS changes the generator setup after each individual measurement.
The second parameter is not mandatory. You can turn it off with the "Y-Axis Enable"
function. In that case, the parameter sweep is represented in a two-dimensional diagram (for example the EVM against the frequency).
Example:
When you define a level range from 0 dBm (start value) to 10 dBm (stop value) with a
stepsize of 1 dB, the parameter sweep would perform 11 measurements on a single
frequency.
When you also define a frequency range between 10 MHz and 20 MHz, and a stepsize
of 1 MHz, the total number of measurements would be 121: 11 power level measurements on each of the 11 frequencies.
Configuration
Configuring the Parameter Sweep
Remote command:
Chapter 6.6.15, "Configuring Parameter Sweeps", on page 276
Synchronizing the levels of signal generator and analyzer
When you sweep the output level of the generator, make sure to synchronize the reference level of the analyzer and the RMS level of the generator to avoid damage to the
RF input of the analyzer (➙ "Couple FSx and SMx Level"). When you do so, the application automatically matches the reference level of the analyzer to the output level of
the generator.
For sensitive DUTs, you can define maximum output level that is not exceeded during
the parameter sweep.
Note that it is mandatory to define the "Expected Gain" of the DUT. Otherwise, the synchronization between the levels can fail or lead to invalid results.
NOTICE! Risk of damage to the RF input of the analyzer.
Make sure to define the correct "Expected Gain". Otherwise, the R&S FPS does not
consider the gain of the amplifier during the level changes on signal analyzer and generator, which in turn can lead to a high-level signal damaging or destroying the RF
input mixer of the analyzer.
With a correct "Expected Gain" value, however, the application is able to attenuate the
signal accordingly.
Remote command:
Synchronization state: CONFigure:PSWeep:ADJust:LEVel[:STATe] on page 276
Expected gain: CONFigure:PSWeep:EXPected:GAIN on page 276
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5 Analysis
The amplifier application provides several tools to get more information about the
results.
Most of these tools work similar to those available in the spectrum application. For
more information about these tools, refer to the R&S FPS user manual.
● Configuring Traces..................................................................................................92
● Using Markers.........................................................................................................96
● Customizing Numerical Result Tables...................................................................100
● Configuring Result Display Characteristics...........................................................102
● Scaling the X-Axis.................................................................................................104
● Scaling the Y-Axis................................................................................................. 105
5.1 Configuring Traces
Analysis
Configuring Traces
The amplifier application provides several tools to configure and evaluate traces.
● Selecting the Trace Information.............................................................................. 92
● Exporting Traces.....................................................................................................94
● Detector Settings.....................................................................................................95
5.1.1 Selecting the Trace Information
Access: [TRACE] > "Trace Config" > "Traces"
Each result display contains one or several traces specific to the corresponding result
type.
The number of traces available for each result display and the information these traces
provide are described in Chapter 3, "Measurements and Result Displays", on page 11.
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Trace Mode
Defines the update mode for subsequent traces.
Clear Write
Max Hold
Min Hold
Average
View
Blank
Remote command:
DISPlay[:WINDow<n>][:SUBWindow<w>]:TRACe<t>:MODE on page 280
Detector
Defines the trace detector to be used for trace analysis.
Positive Peak
Negative Peak
Average
Off
Remote command:
[SENSe:][WINDow<n>:]DETector<t>[:FUNCtion] on page 284
Analysis
Configuring Traces
Overwrite mode (default): the trace is overwritten by each measurement.
The maximum value is determined over several measurements and
displayed. The R&S FPS 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 FPS 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 measurements.
The current contents of the trace memory are frozen and displayed.
Removes the selected trace from the display.
The positive detector displays the maximum level that has been
detected during the measurement.
The negative peak detector displays the minimum level that has been
detected during the measurement.
The average detector displays an RMS average (linear and quadratic) for most traces including EVM. Only for VCC/ICC traces (linear
averaged) the average voltages and currents are displayed.
No specific detector is active and all values are recorded.
Result Type
Defines the result type to be used for trace analysis.
IdealLine
Meas
Model
Reference
Remote command:
DISPlay[:WINDow<n>][:SUBWindow<w>]:TRACe<t>:RESult on page 283
Predefined Trace Settings - Quick Config
Commonly required trace settings have been predefined and can be applied very
quickly by selecting the appropriate button.
Displays a line that equals to a perfect linear device for "AM/AM",
"AM/PM" and "Gain Compression" traces.
Displays the measured signal.
Displays a modeled signal for "AM/AM" and "AM/PM" traces.
Displays the reference signal for "FFT Spectrum" traces.
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Function Trace Settings
Preset All Traces Trace 1: Clear Write
Analysis
Configuring Traces
Set Trace Mode
Max | Avg | Min
Set Trace Mode
Max | ClrWrite | Min
Trace 1: Max Hold
Trace 2: Average
Trace 3: Min Hold
Trace 1: Max Hold
Trace 2: Clear Write
Trace 3: Min Hold
5.1.2 Exporting Traces
Access: [TRACE] > "Trace Config" > "Trace / Data Export"
The functionality to export traces is similar to the Spectrum application. When you
export a trace, the R&S FPS writes the trace data into an ASCII file. You can use the
exported data for further evaluation in other programs like a spreadsheet.
Blank
Blank
Blank
The remote commands required to configure the trace export are described in Chap-
ter 6.7.1, "Configuring Traces", on page 280.
Selecting data to export................................................................................................ 94
Include Instrument & Measurement Settings ............................................................... 95
Decimal Separator ....................................................................................................... 95
Export Trace..................................................................................................................95
Selecting data to export
The "Window(s)" toggle button selects the data that you want to export.
"All Visible" exports all traces in all result displays that are currently visible.
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"Current" exports the traces in the currently selected (highlighted blue) result display.
If you export data from the currently selected result display, you can also select if you
want to export all traces in that result display, or a single trace only from the "Trace(s) /
Columns" dropdown menu.
Remote command:
MMEMory:STORe<n>:TRACe on page 282
Include Instrument & Measurement Settings
Includes additional instrument and measurement settings in the header of the export
file for result data.
Remote command:
FORMat:DEXPort:HEADer on page 282
Decimal Separator
Defines the decimal separator for floating-point numerals for the data export/import
files. Evaluation programs require different separators in different languages.
Remote command:
FORMat:DEXPort:DSEParator on page 281
Analysis
Configuring Traces
Export Trace
The "Export Trace To ASCII File" button opens a dialog box to select a directory and
file name for the ASCII file.
The results are output in the same order as they are displayed on the screen: window
by window, trace by trace, and table row by table row.
Note: 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 FPS base unit user manual.
Remote command:
MMEMory:STORe<n>:TRACe on page 282
5.1.3 Detector Settings
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Max. Trace Points
Sets the maximum number of trace points to be used by detectors.
Remote command:
[SENSe:]DETector<t>:TRACe[:POINt] on page 283
Default Detector
Selects the default detector for R&S FPS-K18 result displays.
Remote command:
[SENSe:]DETector<t>:DEFault[:FUNCtion] on page 283
5.2 Using Markers
The amplifier application provides four markers in most result displays.
● Configuring Markers................................................................................................96
● Configuring Individual Markers................................................................................97
● Positioning Markers...............................................................................................100
Analysis
Using Markers
5.2.1 Configuring Markers
Access: "Overview" > "Result Config" > "Marker Settings"
The "Marker Settings" contain settings that apply to all markers or have a general
effect on marker functionality.
Marker Table Display ....................................................................................................96
Marker Info ...................................................................................................................96
Link Markers Across Windows......................................................................................97
Marker Table Display
Defines how the marker information is displayed.
"On"
"Off"
"Auto"
Remote command:
DISPlay[:WINDow<n>]:MTABle on page 286
Displays the marker information in a table in a separate area beneath
the diagram.
No separate marker table is displayed.
If Marker Info is active, the marker information is displayed within the
diagram area.
(Default) If more than two markers are active, the marker table is displayed automatically.
If Marker Info is active, the marker information for up to two markers
is displayed in the diagram area.
Marker Info
Turns the marker information displayed in the diagram on and off.
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Remote command:
DISPlay[:WINDow<n>]:MINFo[:STATe] on page 286
Link Markers Across Windows
Turns marker coupling across result windows on and off.
When you link markers, moving a marker in one result display moves the marker to the
same sample in another window. This is useful to compare results in result displays
that have different information on their x- and y-axis (for example the AM/AM and
AM/PM results).
Remote command:
CALCulate<n>:MARKer<m>:LINK on page 285
Analysis
Using Markers
5.2.2 Configuring Individual Markers
Access: "Overview" > "Result Config" > "Markers"
The functionality to position markers and query their position is similar to the marker
functionality available in the Spectrum application.
Availability of markers
The "Markers" and "Marker Settings" tabs are available for result displays that support
markers.
If the tabs are unavailable, make sure to select a result display that actually supports
markers from the "Specifics for:" dropdown menu (for example the spectrum FFT result
display).
Note that the amplifier application does not support more than four markers in any
result display.
Selected Marker ...........................................................................................................98
Marker State .................................................................................................................98
Marker Position X-value ...............................................................................................98
Marker Type .................................................................................................................98
Reference Marker ........................................................................................................ 98
Linking to Another Marker ............................................................................................99
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Assigning the Marker to a Trace .................................................................................. 99
All Markers Off ..............................................................................................................99
Marker Table Display ....................................................................................................99
Selected Marker
Marker name. The marker which is currently selected for editing is highlighted orange.
Remote command:
Marker selected via suffix <m> in remote commands.
Marker State
Activates or deactivates the marker in the diagram.
Remote command:
CALCulate<n>:MARKer<m>[:STATe] on page 291
CALCulate<n>:DELTamarker<m>[:STATe] on page 288
Marker Position X-value
Defines the position (x-value) of the marker in the diagram. For normal markers, the
absolute position is indicated. For delta markers, the position relative to the reference
marker is provided.
Remote command:
CALCulate<n>:MARKer<m>:X on page 291
CALCulate<n>:DELTamarker<m>:X on page 289
Analysis
Using Markers
Marker Type
Toggles the marker type.
The type for marker 1 is always "Normal" , the type for delta marker 1 is always
"Delta" . These types cannot be changed.
Note: If normal marker 1 is the active marker, switching the "Mkr Type" activates an
additional delta marker 1. For any other marker, switching the marker type does not
activate an additional marker, it only switches the type of the selected marker.
"Normal"
"Delta"
Remote command:
CALCulate<n>:MARKer<m>[:STATe] on page 291
CALCulate<n>:DELTamarker<m>[:STATe] on page 288
Reference Marker
Defines a marker as the reference marker which is used to determine relative analysis
results (delta marker values).
Remote command:
CALCulate<n>:DELTamarker<m>:MREFerence on page 288
A normal marker indicates the absolute value at the defined position
in the diagram.
A delta marker defines the value of the marker relative to the specified reference marker (marker 1 by default).
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Linking to Another Marker
Links the current marker to the marker selected from the list of active markers. If the xaxis value of the initial marker is changed, the linked marker follows to the same position on the x-axis. Linking is off by default.
Using this function you can set two markers on different traces to measure the difference (e.g. between a max hold trace and a min hold trace or between a measurement
and a reference trace).
Remote command:
CALCulate<n>:MARKer<ms>:LINK:TO:MARKer<md> on page 290
CALCulate<n>:DELTamarker<ms>:LINK:TO:MARKer<md> on page 288
CALCulate<n>:DELTamarker<m>:LINK on page 287
Assigning the Marker to a Trace
The "Trace" setting assigns the selected marker to an active trace. The trace determines which value the marker shows at the marker position. If the marker was previously assigned to a different trace, the marker remains on the previous frequency or
time, but indicates the value of the new trace.
If a trace is turned off, the assigned markers and marker functions are also deactivated.
Remote command:
CALCulate<n>:MARKer<m>:TRACe on page 291
Analysis
Using Markers
All Markers Off
Deactivates all markers in one step.
Remote command:
CALCulate<n>:MARKer<m>:AOFF on page 290
Marker Table Display
Defines how the marker information is displayed.
"On"
"Off"
"Auto"
Remote command:
DISPlay[:WINDow<n>]:MTABle on page 286
Displays the marker information in a table in a separate area beneath
the diagram.
No separate marker table is displayed.
If Marker Info is active, the marker information is displayed within the
diagram area.
(Default) If more than two markers are active, the marker table is displayed automatically.
If Marker Info is active, the marker information for up to two markers
is displayed in the diagram area.
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5.2.3 Positioning Markers
Peak Search ...............................................................................................................100
Search Next Peak ...................................................................................................... 100
Search Minimum ........................................................................................................ 100
Search Next Minimum ................................................................................................100
Peak Search
Sets the selected marker/delta marker to the maximum of the trace. If no marker is
active, marker 1 is activated.
Remote command:
CALCulate<n>:MARKer<m>:MAXimum[:PEAK] on page 295
CALCulate<n>:DELTamarker<m>:MAXimum[:PEAK] on page 293
Search Next Peak
Sets the selected marker/delta marker to the next (lower) maximum of the assigned
trace. If no marker is active, marker 1 is activated.
Remote command:
CALCulate<n>:MARKer<m>:MAXimum:NEXT on page 295
CALCulate<n>:MARKer<m>:MAXimum:RIGHt on page 295
CALCulate<n>:MARKer<m>:MAXimum:LEFT on page 294
CALCulate<n>:DELTamarker<m>:MAXimum:NEXT on page 293
CALCulate<n>:DELTamarker<m>:MAXimum:RIGHt on page 293
CALCulate<n>:DELTamarker<m>:MAXimum:LEFT on page 292
Analysis
Customizing Numerical Result Tables
Search Minimum
Sets the selected marker/delta marker to the minimum of the trace. If no marker is
active, marker 1 is activated.
Remote command:
CALCulate<n>:MARKer<m>:MINimum[:PEAK] on page 296
CALCulate<n>:DELTamarker<m>:MINimum[:PEAK] on page 294
Search Next Minimum
Sets the selected marker/delta marker to the next (higher) minimum of the selected
trace. If no marker is active, marker 1 is activated.
Remote command:
CALCulate<n>:MARKer<m>:MINimum:NEXT on page 296
CALCulate<n>:MARKer<m>:MINimum:LEFT on page 295
CALCulate<n>:MARKer<m>:MINimum:RIGHt on page 296
CALCulate<n>:DELTamarker<m>:MINimum:NEXT on page 294
CALCulate<n>:DELTamarker<m>:MINimum:LEFT on page 293
CALCulate<n>:DELTamarker<m>:MINimum:RIGHt on page 294
5.3 Customizing Numerical Result Tables
Access: "Overview" > "Result Config" > "Table Config"
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