Rohde&Schwarz R&S®SMW200A RF Ports Alignment user manual User Manual
R&S®RFPAL, R&S®SMW-K545
RF Ports Alignment
User Manual
(;ÝC<2)
1179191202
Version 01
This manual describes the following application and software option:
●
R&S®RFPAL, version 1.0
Order number: 1414.7019.02
●
R&S®SMW-K545
Order number: 1414.6429.02
Related firmware version of the R&S®SMW200A: FW 4.80.041.xx and later
© 2020 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.
1179.1912.02 | Version 01 | R&S®RFPAL, R&S®SMW-K545
Throughout this manual, products from Rohde & Schwarz are indicated without the ® symbol.
R&S®RFPAL, R&S®SMW-K545
Contents
1 Documentation Overview......................................................................5
2 About RF Ports Alignment.................................................................... 6
3 R&S RFPAL........................................................................................... 11
4 RF Ports Alignment at the SMWs....................................................... 40
Annex.................................................................................................... 72
A Files and Data.......................................................................................72
Contents
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Contents
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1 Documentation Overview
This manual contains two main parts:
●
All information about the R&S RFPAL application which determines correction data
for RF ports alignment, see Chapter 3, "R&S RFPAL", on page 11
●
RF Ports alignments on the R&S SMW signal generators in a multi-instrument
setup on basis of the results of RFPAL, see Chapter 4, "RF Ports Alignment at the
SMWs", on page 40
Chapter 2, "About RF Ports Alignment", on page 6 describes the principle and com-
mon aspects of RF ports alignment.
RF ports alignment at the signal generators is embedded in the SMW's multi-instrument capabilities. See the R&S SMW200A Vector Signal Generator user manual for
comprehensive information about multi-instrument usage, general GUI and SCPI handling.
Documentation Overview
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2 About RF Ports Alignment
RF ports alignment refers to test setups where the DUT gets several RF signals which
have to be coherent. The RF signals come from several R&S SMW signal generators
(multi-instrument setup). Due to own signal processing in the signal generators, the
resulting RF signals at the out ports of the instruments can differ in phase, time delay
and power in dependency to the signal frequency and power. RF ports alignment corrects such signal deviations. Consequently, the DUT receives coherent RF signals.
RF ports alignment consists of two processes:
●
Measurement of the signal deviations (or misalignments) of the RF signals from the
signal generators and creation of correction data. This task is done by
R&S RFPAL. S-parameter files (s<n>p files) are included to compensate signal
deviations by RF components in the RF paths like cables. The measurements are
carried out with the test setup for testing the DUT but with additional measurement
equipment. One signal generator is the primary instrument and its first used RF
port is the reference port. R&S RFPAL measures the signal differences between
the reference port and the other ports to calculate the required correction data.
●
Application of the correction data at the signal generators. The primary instrument
distributes correction data to the other signal generators. During test execution, the
signal generators modify their RF signals according to the correction data and
transmit the corrected signals synchronously. This functionality is enabled by the
SMW-K545 option.
Correction data is applied in real time (not by predistorting given waveforms) and
can therefore be used in real time applications such as PDW streaming.
About RF Ports Alignment
Aligned RF Signals from Coupled Signal Generators
RFPAL delivers the correction data to the primary instrument. It does not take part in
the second process. See Chapter 3, "R&S RFPAL", on page 11 for the detailed
description of the application.
When correction data has been provided to the primary instrument and the SMWKF545 option is available, the configurations for RF ports alignment are automatically
carried out. You can inspect the configurations via the primary instrument's graphical
user interface or via SCPI commands. To apply RF ports alignment, you only have to
enable it at the primary instrument. See Chapter 4, "RF Ports Alignment at the SMWs",
on page 40 for the detailed description.
2.1 Aligned RF Signals from Coupled Signal Generators
The figure shows the testing situation when alignment of the RF signals is applied by
the signal generators using the alignment data from R&S RFPAL.
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Figure 2-1: Aligned RF signals
About RF Ports Alignment
Aligned RF Signals from Coupled Signal Generators
Characteristics:
●
The RF signals originate from several signal generators and are denoted by the RF
ports. Each RF port is the source for one signal path to the DUT.
●
To create reproducible relations between the RF signals (that nevertheless experience misalignments), the signal generators are coupled. One signal generator is
the primary instrument. The other signal generators act as secondary instruments.
The signal generators share several signals; here the primary instrument provides
them to the secondary instruments:
– Reference signal (REF)
– Baseband synchronization and trigger signal
– Local oscillator (LO)
So all instruments are synchronized using the same reference signals, trigger sig-
nals and local oscillator.
Alternatively, the reference signal and the local oscillator can be provided by external sources.
●
The first RF port of the primary instrument serves as reference port. The alignment
of the RF signals from other ports is done relative to the RF signal from the reference port.
●
The primary signal generator gets the correction data (alignment data and s<n>p
data) from RFPAL. The other signal generators get their correction data from the
primary one. Alignment data compensates misalignments between the RF signals
at the different RF ports. s<n>p data compensates signal deviations in the RF
paths caused by RF components such as cables and splitters.
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2.2 Misaligned RF Signals and Alignment in Signal Generators
Alignment only works fine if the relations between the RF signals from the different RF
ports are reproducible. Therefore, trigger, clock signal and local oscillator are coupled
for the signal generators. The trigger coupling avoids trigger jitter. Misalignments still
occur regarding LO phase, time delay and signal amplitude. The figure illustrates the
different contributions to misalignments of signals and the effect of alignment with
RFPAL.
About RF Ports Alignment
Misaligned RF Signals and Alignment in Signal Generators
Figure 2-2: Contributions to misalignments and alignment effects
The table describes causes of misalignments and how misalignments are compensated in the signal generators.
Table 2-1: Causes for misalignment and their compensation
Effect Caused by Compensated by
LO phase difference Length of the cables used for the distribution of the
LO signal
Phase errors in splitters or amplifiers
Level difference Attenuation in the RF path Adjusting the RF level
Time delay Length of the cables used for the distribution of the
trigger signal
Offsetting the signal in the baseband (digital domain)
Applying I/Q delay
The compensations require different settings if carried out manually. RFPAL supports
an integrated compensation process.
Alignment over frequency and power
The phase/power/delay differences between the RF signals of the different ports
depend on the frequency and the signal power. The following figure schematically
shows the phase over frequency for two RF ports before alignment (upper left part)
and after alignment (lower left part). "bw" is the modulation bandwidth (or signal bandwidth).
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Figure 2-3: Phase responses and relative compensation
RF A is the reference port. The phase values vary over frequency for both RF ports but
with different courses. Using the alignment data derived from the measurements of the
network analyzer, RF ports alignment adjusts the phase course for port RF B to that of
port RF A. This alignment is relative (as are the measurements of the network analyzer): The RF signals for RF A and RF B are in phase but no compensation is done to
get a constant phase over frequency. Power levels and delays are aligned accordingly,
that is, alignment is done relative to the reference port.
About RF Ports Alignment
Misaligned RF Signals and Alignment in Signal Generators
Also, the signal power over frequency can be measured for the reference port by a
power sensor (absolute power measurement). In this case an additional power compensation step is carried out: The power variations measured at the reference port are
compensated for the reference port and all other RF ports to get a constant power level
over frequency for all RF ports.
Figure 2-4: Power compensation with data from the power sensor
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2.3 Required Options
R&S RFPAL is not related to a software option. Instead, options are required for the
R&S SMWs to interplay with RFPAL and to use the alignment data according to the following list.
●
R&S SMW-K545 (for each signal generator): RF ports alignment
●
R&S SMW-K544 (per signal path): User-defined frequency response correction
●
R&S SMW-K61 (per signal path): Multi-carrier continuous wave
●
R&S SMW-B9 (per signal path): Wideband baseband generator
●
R&S SMW-B13XT: Wideband baseband main module two I/Q paths to RF
●
R&S SMW-B90: Phase coherence
●
R&S SMW-B1003 (for example): RF frequency from 100 kHz to 3 GHz
If only standard baseband signals are required, you can use R&S SMW-B10 and R&S
SMW-B13T instead of R&S SMW-B9 and R&S SMW-B13XT.
Note that R&S RFPAL includes a QuickStep standard option to perform the alignment
procedures. For modifying the alignment procedures (only for special use cases,
expert knowledge required), the QuickStep development option (R&S QS-DEV) is
required.
About RF Ports Alignment
Required Options
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R&S RFPAL
3 R&S RFPAL
3.1 About R&S RFPAL
R&S RFPAL is applicable for test scenarios where one or a few R&S SMW signal generators provide several RF signals that have to be coherent. Due to signal processing
and timing in the signal generators, the resulting RF signals at the out RF ports of the
instruments can differ in phase, time delay and power depending on the RF signal frequency and power.
R&S RFPAL assists in providing coherent RF signals over all RF paths at the DUT: It
measures relative signal deviations between RF paths and provides correction data for
the R&S SMWs. The R&S SMWs apply the correction data to compensate the deviations. The RF signals of the different paths are aligned in this way. RFPAL is short for
RF ports alignment. For applying the correction data at the signal generators, they
have to be equipped with the SMW-K545 option.
Correction data is applied in real time (not by predistorting given waveforms) and can
therefore be used in real time applications such as PDW streaming.
About R&S
RFPAL
Figure 3-1: RF paths to be aligned
R&S RFPAL is an application that runs on a PC which is LAN-connected to the signal
generators. For alignment measurements, the test setup includes a network analyzer
and often a power sensor. R&S RFPAL controls the signal generators and the measurement instruments.
If there are other RF components in the RF paths from the RF ports to the measurement instruments than to the DUT, the measurement results of the measurement
instruments would not reflect the situation at the DUT. The different RF components
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(for example splitters and cables) would cause different signal deviations. RFPAL supports compensation of such signal deviations by S-parameter files ( s<n>p files) which
have to be provided.
Without R&S RFPAL, alignment of the RF signals in a test setup with several signal
generators can be time-consuming and erroneous: First, the test and measurement
instruments have to be controlled manually in a coordinated way for the alignment
measurements. Second, the resulting corrections have to be provided manually in different parameters at the signal generators. It has to be taken care that all RF-related
parameters of the generator are maintained.
R&S RFPAL uses R&S QuickStep to control the signal generators and to perform the
alignment procedures.
Key facts
RFPAL interplays with one or several R&S SMWs, a network analyzer and optionally a
power meter.
RFPAL provides:
●
Representation of the test setup and configuration of the alignment measurements
●
Coordinated control of the R&S SMWs and measurement instruments during alignment measurements; control of an R&S OSP RF switching unit, if used, is included
●
Measurement of alignment data for correcting deviations in delay, phase, power
level (PEP)
●
Calibration support for an R&S network analyzer
●
Integration of S-parameter files (s<n>p files) for RF path components and of calibration files for R&S network analyzer and R&S OSP
●
Check of alignment results (by applying correction data)
●
Provision of correction data (alignment data and s<n>p files) to the primary
R&S SMW
R&S RFPAL
About R&S RFPAL
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3.2 GUI Overview
Figure 3-2: GUI overview
R&S RFPAL
GUI Overview
The graphical user interface is structured in three major areas:
●
Configuration
●
Control
●
Content
In the configuration area, you configure the setup for alignment measurements. The
settings can be saved via the top menu "File > Save Setup" or previous settings can be
loaded via "File > Load Setup".
You start and control the alignment measurements via "Calibrate" in the control area.
The information in the content area is distributed in several tabs:
●
The "Calibration" tab shows a graphical representation of the setup as configured
in the configuration area and used for the alignment measurements.
●
The "Logging" tab contains processing and status information and event reports.
You see what is going on. If errors occur, the information in this tab helps you to
understand the problem and how to solve it.
●
The "QuickCheck Result" displays charts for magnitude/phase/delay errors detected with a "QuickCheck" action. The "QuickCheck" runs the signal generators with
correction data applied and measures the remaining misalignments.
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3.3 Concepts
3.3.1 Test Setup for Alignment Measurements
R&S RFPAL
Concepts
Figure 3-3: Test setup including an RF switching unit and relevant paths
The figure shows a useful instrument setup for RFPAL alignment measurements.
Characteristics:
●
The measurements instruments, a network analyzer and a power sensor, are
embedded in the test setup that is used for executing tests after alignment. No test
setup changes are required after alignment.
●
Optionally, an RF switching unit connects the RF signal path sections at the signal
generator side and the signal path sections at the DUT side. RFPAL controls the
switching unit. It can select the paths to be used for measurements, so the paths
are switched automatically during RFPAL operations. A configuration file is
required at the switching unit that defines the required paths.
If no switching unit is used, the required connections between RF ports and network analyzer have to be established manually (assisted by dialogs) during the
measurement procedures.
●
The components in the RF signal paths to the DUT can differ from the components
to the measurement instruments. So, DUT paths are distinguished from the corresponding calibration paths to the network analyzer and from the level calibration
path (corresponding paths: same signal generator's RF port). See in Integration of
S-Parameter Files how the different path types are used.
Tip: Use cables of the same length and type for corresponding paths and all RF
ports. Consequently, the relative signal deviations are minimized.
●
The power sensor is used for measuring the RF signal power at the reference port.
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●
For calibration of the network analyzer, a power splitter can be integrated in the
test setup. If an RF switching unit is used, the in port and the out ports of the power
splitter are connected to the switching unit, and the configuration file for the switching unit defines the RF paths through the power splitter. RFPAL commands the unit
to select the right RF paths to and from the power splitter for the calibration of the
network analyzer. So, no change of the test setup and no manual connection
establishment is required when proceeding from network analyzer calibration to
alignment measurements.
3.3.2 Integration of S-Parameter Files
The network analyzer carrying out the alignment measurements experiences the same
misalignments as the DUT if the DUT paths and the corresponding calibration paths
are equivalent. This is the case if the RF connections to both devices consist of the
same RF components (for example cables of the same type and lengths are used). So
the alignment measurements match the situation at the DUT, and applying RF port
alignment with the produced alignment data exactly aligns the RF signals at the DUT.
In other words, alignment is required at the DUT reference plane (see the figure), and
the measurement plane of the network analyzer matches the DUT reference plane.
R&S RFPAL
Concepts
Figure 3-4: Equivalent DUT and calibration paths
The DUT paths and calibration paths often contain different RF components, which
cause different signal deviations. These deviations have to be compensated for matching the situations at the measurement reference plane and the DUT reference plane.
See the figure for typical conditions.
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R&S RFPAL
Concepts
Figure 3-5: Different DUT paths and calibration paths that require S-parameter compensation
RFPAL integrates compensation of signal deviations from RF components in the RF
paths by S-parameter files (s<n>p files). The different RF path types are handled as
follows:
●
Calibration path: Gets the S-parameter files for the components in the RF signal
path between RF port and network analyzer, particularly for the switching unit.
RFPAL uses these S-parameter files for compensating deviations in these paths
during the alignment measurements. So alignment data is produced as if the measurements were carried out in the RF ports reference plane. Applying the S-parameter files shifts the measurement reference plane to the RF ports reference plane.
●
DUT path: Gets the S-parameter files for cables, splitters and other components in
that path. RFPAL forwards these calibration files to the primary signal generator
after the alignment measurements. They are applied by the signal generators to
compensate the signal deviations in the DUT paths. In combination with alignment
data related to the RF ports reference plane, the DUT gets aligned RF signals.
Applying the S-parameter files can be seen as deembedding of the DUT: By
removing the signal deviations between the RF ports of the signal generators and
the DUT, the reference plane where the RF signals are aligned is shifted from the
RF ports reference plane to the DUT reference plane.
●
Level calibration path: Gets the S-parameter files for the components in the RF signal path between reference port and power sensor. RFPAL uses these S-parameter files in the same way as those for the calibration paths.
Measuring the frequency responses of the RF components in the different RF paths is
not part of RFPAL. Usually, the frequency responses of the RF components are known
and s<n>p calibration files for them are already available.
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3.3.3 Alignment Measurements
The figure shows schematically how misalignments between two RF ports of one or
two signal generators are measured with a network analyzer.
R&S RFPAL
Concepts
Figure 3-6: Alignment measurement for RF A and RF B
With connections between the reference port and a second RF port to the network
analyzer established, RFPAL commands the signal generators to generate appropriate
RF signals. Instead of continuous-wave signals to be swept over the signal bandwidth,
multi-carrier continuous wave (MCCW) signals are used. The network analyzer measures the differences between the RF signals over the frequencies and over signal
power levels as configured in RFPAL.
Afterwards, if more than two RF ports have to be aligned, the second RF port is
changed and the same alignment measurement is carried out for the new pair of reference port and second RF port, and so on for all RF ports to be aligned. So, the reference port is always connected to the same input port of the network analyzer and the
second port changes for each measurement. The connection to the next RF port is
changed either automatically via RF switching box under control of RFPAL or manually.
Power measurement with the power sensor is performed only for the reference port
(relative power differences between the reference port and the other RF ports are
already covered by the network analyzer measurements).
3.3.4 Calibration of the Network Analyzer
RFPAL supports calibration of the network analyzer. Two ports of the network analyzer
are used to measure the signal differences of two RF ports of the signal generators.
Calibration of the network analyzer makes sure that any differences in the frequency
responses of the receivers behind the ports are compensated and do not influence the
alignment measurements. For determining the differences of frequency responses in
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the network analyzer, the same RF signal is fed to the two ports. The network analyzer
measures and evaluates the differences between the responses.
If direct receiver access is enabled for the network analyzer, its "Ref" and "Meas" connectors can alternatively be used (there is a receiver behind "Ref" and one behind
"Meas"). Notice that when using direct receiver access, the standard calibration of the
network analyzer is no more valid.
Two methods for calibration of the network analyzer are supported:
●
Power splitter method: The primary signal generator generates appropriate RF signals and transmits them to a power splitter where they are split. The resulting two
identical RF signals are fed to the two network analyzer receivers to be calibrated.
RFPAL controls both the primary signal generator and the network analyzer and
applies the s<n>p calibration file of the power splitter. This method fits to the test
setup that is later used for testing. Only the power splitter is added to the test setup
and its connections have to be established.
R&S RFPAL
Concepts
Figure 3-7: Calibration of network analyzer with power splitter and signal generator
Use the power splitter method for the R&S ZVA. The following method is not valid
for this instrument.
●
TOSM method: This calibration type yields the most accurate calibration results
(reflection and transmission measurements; 12-term error correction model). It
relies on automatic calibration procedures of the network analyzer. Equivalent VNA
standard calibration is also possible.
TOSM (Through – Open – Short – Match) calibration can be done in two ways. For
both, the network analyzer generates RF signals, transmits them to and through
standard units, measures the responses and evaluates the differences between
generated RF signals and responses:
– Using a calibration kit for the network analyzer: The Short, Open and Match
standard from the kit are connected to one port, the Through standard is put
between this port and the second one. See the network analyzer's documentation. RFPAL is not involved. This calibration must be done at the network analyzer before RFPAL is used. RFPAL just gets the name of the resulting calibration file.
– Using a calibration unit: It replaces the standards from a calibration kit, and full
automation is possible. See again the network analyzer's documentation.
Though the calibration procedures are carried out completely at the network
analyzer, RFPAL assists for this type of calibration: If the calibration unit is inte-
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grated in the test setup at RFPAL, RFPAL can control not only the network analyzer but also the calibration unit and the calibration. The results of the calibration are stored in a calibration file which the user has to specify in RFPAL. Later
on, RFPAL loads this file onto the network analyzer.
3.3.5 Delivery of Correction Data
Having completed the alignment measurements, RFPAL delivers the alignment data
and s<n>p files for the DUT paths for all RF ports to the primary signal generator (via
*.rfsa archive file). The combination of alignment and s<n>p data is called correction
data. Further distribution of the correction data and application of the correction data,
which aligns the RF signals, is done at the signal generators without participation of
RFPAL.
3.3.6 QuickStep Behind the Scene
R&S QuickStep is an application that configures test procedures, runs test plans –
sequences of individual tests together with scheduling and execution information – and
evaluates the results. During test execution, R&S QuickStep controls the test equipment via SCPI commands. R&S QuickStep also provides the calibration and alignment
procedures.
R&S RFPAL
Preparing for Use
The alignment procedures cover the typical use cases. To adapt the alignment procedures for special test scenarios, it is possible to modify the alignment procedures.
Therefore, the R&S QuickStep development option is required.
3.4 Preparing for Use
3.4.1 Preliminaries
3.4.1.1 Required Hardware
RFPAL is intended to be used on a PC. No special hardware and other software is
required. The tool runs on Windows 7 or 10.
3.4.1.2 Required Options
R&S RFPAL is not related to a software option. Instead, options are required for the
R&S SMWs to interplay with RFPAL and to use the alignment data, particularly R&S
SMW-K545 RF ports alignment.
Note that R&S RFPAL includes a QuickStep standard option to perform the alignment
procedures. For modifying the alignment procedures (only for special use cases,
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expert knowledge required), the QuickStep development option (R&S QS-DEV) is
required.
3.4.2 Installing and Starting RFPAL
Installing RFPAL
The tool is provided as .exe installation file. You install the tool on the PC that controls
the alignment procedures.
1. Download the installation file from the following destination.
https://www.rohde-schwarz.com/software/rfpal
2. Double-click the file.
An installation dialog guides you through the installation process.
3. Accept the license conditions and click "Next".
RFPAL is installed on your PC. An "R&S RFPAL" icon is added on the desktop for
starting the tool.
R&S RFPAL
Operation
Starting the tool
► Double-click the "R&S RFPAL" icon on the desktop.
The application starts and its graphical user interface opens with a start page.
Either click "New setup" to create a setup file that has only some default settings
and that you fill with configuration data. Or click "Load setup" to load a setup file
from an earlier RFPAL session. Then, the actual RFPAL GUI is opened representing the settings stored in the setup file.
3.5 Operation
RFPAL is operated by a sequence of steps.
●
Configure the Setup
●
Configure RF Path Switching and the Measurement Instruments
●
Configure the Alignment Measurements
●
Execute the Measurements and Transfer Correction Data
Prerequisites
Before applying the following procedures:
●
Make sure that the cabling connections have been established. Particularly, RFPAL
needs LAN connections to the instruments to be controlled.
●
Switch on the instruments.
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Set up all instruments at once in the connection configuration dialog when opening it
the first time during the RFPAL configuration (see Connection configuration dialog).
Then, you only have to select the right instruments in the later RFPAL configuration
steps.
3.5.1 Configure the Setup
The setup of the signal generators and the connections is configured by parameters in
the "RF Ports" and "LO/REF Configuration" sections of the configuration area on the
left side. After saving the configuration, the "Calibration" tab displays a schematic diagram of the instruments and paths as configured.
Use case
No setup is loaded. Instead, a new setup is built by configurations in the "Calibration"
area.
Prerequisites
R&S RFPAL
Operation
●
S-parameter files for the components in the RF paths (between RF ports and the
DUT and the measurement instruments) are available if needed (see Integration of
S-Parameter Files).
To configure the RF ports (including signal generators and RF paths)
1. Select "File > New Setup" from the top menu, enter a filename for the .xml file that
describes the setup and store the file.
2. Select "RF Ports" in the configuration area on the left.
3. For each RF port in your physical test setup, add an RF port section by clicking the
"+ Add RF Port" field, and configure each section as described in the following
steps.
4. Enter an RF port name from the loaded test setup for "RF Port Name".
Note: The first RF port is always the reference port. The signal generator with that
port is the primary instrument.
5. Open the "Config" dialog, add the signal generator for the RF port (for example
with "Search Instrument" if the instrument is already connected and running in the
LAN).
6. Click "Save & Select" while the row for the signal generator is highlighted. The dia-
log is closed and the device name of the signal generator from the "Config" dialog
is displayed in the "Device Name" field.
7. Select the used "RF Port".
8. For the components in the signal path from the signal generator's RF port to the
DUT, add the related S-parameter files in the "DUT Path" section. Therefore, start
with "Add Row".
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9. For the components in the signal path from the signal generator's RF port to the
calibration instrument (for example a network analyzer), add the related S-parameter files in the "Calibration Path" section. Therefore, start with "Add Row".
10. For the reference port of the primary instrument, the "Level Calibration Path" sec-
tion is available. For the components in the signal path from the reference port to
the level calibration instrument (power sensor), add the related S-parameter files in
the "Calibration Path" section. Therefore, start with "Add Row".
To configure the local oscillator and the reference signal
In this example procedure, it is assumed that the primary signal generator provides the
local oscillator and the REF signal, all secondary signal generators get the LO and
REF signals from the primary instrument.
Default settings are provided for this use case. So, if you decide to operate with this
use case, you can omit the following procedure. Nevertheless, the procedure illustrates
exemplarily how to configure in this section.
1. Select "LO / REF Configuration" in the configuration area on the left.
R&S RFPAL
Operation
2. Configure the parameters according to your physical test setup.
● Enable "LO Coupling".
● Select "Star" for the "LO Configuration".
● Select "Intern" for the "LO Source".
● Select "Intern" for the "REF Source".
To save the configuration
► Select "File > Save Setup" from the top menu.
Vice versa, you get the saved configuration via "File > Load Setup".
3.5.2 Configure RF Path Switching and the Measurement Instruments
RF path switching means changing one connection between an RF port of a signal
generator and the network analyzer (the other connection to the reference RF port is
kept).
Measurement instruments are the network analyzer and the power sensor.
To configure the RF path switching
If an RF switching unit is integrated in the test setup, you can use automatic switching:
RFPAL commands the switching unit to establish the required connections.
Else, manual switching is required where you reconnect manually.
1. Select "RF Path Switching" in the configuration area on the left.
2. Select the "Switching Mode" according to your needs.
3. In case of "Automatic" "Switching Mode":
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R&S®RFPAL, R&S®SMW-K545
● Configure and select the RF switching unit via the "Config" dialog.
● Enter the name of the configuration file that defines the mapping between the
ports of the RF switching unit and the RF path sections (this file must be available on the RF switching unit).
To configure the network analyzer
Calibration of the network via power splitter is included. See Calibration of the Network
Analyzer for details.
1. Expand "Measurement Instruments" in the configuration area on the left. Make
sure that the checkbox at the "Vector Network Analyzer" field is ticked and expand
the field.
2. Get the "Device Name" of the network analyzer via the Config dialog and "Save &
Select".
If the network analyzer is not yet available in the "Config" dialog, add the instrument in the dialog and select it.
3. "Number of Ports" shows how many ports of the network analyzer are used for the
alignment measurements. This parameter is read-only.
R&S RFPAL
Operation
4. Keep "Direct Receiver Access" disabled.
5. Select "Power Splitter" for the "Calibration Mode".
A table for S-parameter files is displayed.
6. Select the S-parameter file for compensating signal deviations by the power splitter
(only for calibration).
To configure the power meter
1. Still in the "Measurement Instruments" area, make sure that the checkbox at the
"Power Meter" field is ticked and expand the field.
2. Get the "Device Name" of the power meter via the "Config" dialog and "Save &
Select".
To save the configuration
► Select "File > Save Setup" from the top menu.
3.5.3 Configure the Alignment Measurements
The configurations for the alignment measurements are done in the "Calibration
Parameters" section in the configuration area on the left.
To configure the RF signals for alignment measurements
1. Select "Calibration Parameters" in the configuration area on the left.
2. Specify the carrier frequencies used for the calibration measurements.
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