R&S®SMBVB-K544
User-Defined Frequency Response
Correction
User Manual
(;ÜßÕ2)
1178817102
Version 09
This document describes the following software options:
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R&S®SMBVB-K544 User-Defined Frequency Response Correction (1423.8150.xx)
This manual describes firmware version FW 5.00.044.xx and later of the R&S®SMBV100B.
© 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.
1178.8171.02 | Version 09 | R&S®SMBVB-K544
The following abbreviations are used throughout this manual: R&S®SMBV100B is abbreviated as R&S SMBVB; the license types
02/03/07/11/13/16/12 are abbreviated as xx.
R&S®SMBVB-K544
Contents
1 Welcome to the user-defined frequency response correction option
................................................................................................................. 5
1.1 Accessing the frequency response dialog................................................................. 5
1.2 What's new.....................................................................................................................5
1.3 Documentation overview..............................................................................................6
1.3.1 Getting started manual....................................................................................................6
1.3.2 User manuals and help................................................................................................... 6
1.3.3 Service manual............................................................................................................... 6
1.3.4 Instrument security procedures.......................................................................................6
1.3.5 Printed safety instructions............................................................................................... 7
1.3.6 Data sheets and brochures............................................................................................. 7
Contents
1.3.7 Release notes and open source acknowledgment (OSA).............................................. 7
1.3.8 Application notes, application cards, white papers, etc...................................................7
1.4 Scope............................................................................................................................. 8
1.5 Notes on screenshots...................................................................................................8
2 About frequency response correction................................................. 9
2.1 Required options.........................................................................................................11
2.2 Supported file formats................................................................................................ 11
2.2.1 S-parameters (Touchstone) files....................................................................................11
2.2.2 Frequency response (FR) files......................................................................................14
3 Frequency response configuration and settings..............................15
3.1 General settings.......................................................................................................... 15
3.2 User-defined correction..............................................................................................17
3.2.1 Common settings.......................................................................................................... 18
3.2.2 User data S-parameter settings.................................................................................... 20
3.2.3 User data additional FR settings................................................................................... 21
3.2.4 Data overview............................................................................................................... 23
4 How to apply user-defined frequency response corrections.......... 25
5 Remote-control commands.................................................................29
5.1 Programming examples............................................................................................. 30
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5.2 General commands.....................................................................................................32
5.3 Common commands...................................................................................................34
5.4 S-parameter commands............................................................................................. 36
5.5 Frequency response (FR) list commands.................................................................39
List of commands................................................................................ 41
Index......................................................................................................42
Contents
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1 Welcome to the user-defined frequency
response correction option
The R&S SMBVB-K544 is a firmware application that adds functionality for userdefined frequency response corrections.
The R&S SMBVB-K544 features include:
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This user manual contains a description of the functionality that the application provides, including remote control operation.
Welcome to the user-defined frequency response correction option
What's new
Frequency response compensation of internally generated baseband signals by
user-defined data
Cascading of up to 10 scattering parameter files, incl. ports configuration and orientation of the correction chain
Compensation with up to 5 additional frequency responses correction files
Absolute level correction at center frequency
Compensation in real time
All functions not discussed in this manual are the same as in the base unit and are
described in the R&S SMBV100B user manual. The latest version is available at:
www.rohde-schwarz.com/manual/SMBV100B
Installation
You can find detailed installation instructions in the delivery of the option or in the
R&S SMBV100B service manual.
1.1 Accessing the frequency response dialog
To open the dialog with user-defined frequency response correction settings
► In the block diagram of the R&S SMBV100B, select "I/Q Mod > Frequency
Response".
A dialog box opens that displays the provided general settings.
Frequency compensation is not performed immediately. Load suitable files first.
1.2 What's new
This manual describes firmware version FW 5.00.044.xx and later of the
R&S®SMBV100B.
Compared to the previous version there are editorial changes only.
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1.3 Documentation overview
This section provides an overview of the R&S SMBV100B user documentation. Unless
specified otherwise, you find the documents on the R&S SMBV100B product page at:
www.rohde-schwarz.com/manual/smbv100b
1.3.1 Getting started manual
Introduces the R&S SMBV100B and describes how to set up and start working with the
product. Includes basic operations, typical measurement examples, and general information, e.g. safety instructions, etc. A printed version is delivered with the instrument.
1.3.2 User manuals and help
Separate manuals for the base unit and the software options are provided for download:
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Welcome to the user-defined frequency response correction option
Documentation overview
Base unit manual
Contains the description of all instrument modes and functions. It also provides an
introduction to remote control, a complete description of the remote control commands with programming examples, and information on maintenance, instrument
interfaces and error messages. Includes the contents of the getting started manual.
Software option manual
Contains the description of the specific functions of an option. Basic information on
operating the R&S SMBV100B is not included.
The contents of the user manuals are available as help in the R&S SMBV100B. The
help offers quick, context-sensitive access to the complete information for the base unit
and the software options.
All user manuals are also available for download or for immediate display on the Internet.
1.3.3 Service manual
Describes the performance test for checking compliance with rated specifications, firmware update, troubleshooting, adjustments, installing options and maintenance.
The service manual is available for registered users on the global Rohde & Schwarz
information system (GLORIS):
https://gloris.rohde-schwarz.com
1.3.4 Instrument security procedures
Deals with security issues when working with the R&S SMBV100B in secure areas. It
is available for download on the Internet.
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1.3.5 Printed safety instructions
Provides safety information in many languages. The printed document is delivered with
the product.
1.3.6 Data sheets and brochures
The data sheet contains the technical specifications of the R&S SMBV100B. It also
lists the options and their order numbers and optional accessories.
The brochure provides an overview of the instrument and deals with the specific characteristics.
See www.rohde-schwarz.com/brochure-datasheet/smbv100b
1.3.7 Release notes and open source acknowledgment (OSA)
The release notes list new features, improvements and known issues of the current
firmware version, and describe the firmware installation.
Welcome to the user-defined frequency response correction option
Documentation overview
The open-source acknowledgment document provides verbatim license texts of the
used open source software.
See www.rohde-schwarz.com/firmware/smbv100b
1.3.8 Application notes, application cards, white papers, etc.
These documents deal with special applications or background information on particular topics.
See www.rohde-schwarz.com/application/smbv100b
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1.4 Scope
Tasks (in manual or remote operation) that are also performed in the base unit in the
same way are not described here.
In particular, it includes:
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For a description of such tasks, see the R&S SMBV100B user manual.
Welcome to the user-defined frequency response correction option
Notes on screenshots
Managing settings and data lists, like saving and loading settings, creating and
accessing data lists, or accessing files in a particular directory.
Information on regular trigger, marker and clock signals and filter settings, if appropriate.
General instrument configuration, such as checking the system configuration, configuring networks and remote operation
Using the common status registers
1.5 Notes on screenshots
When describing the functions of the product, we use sample screenshots. These
screenshots are meant to illustrate as many as possible of the provided functions and
possible interdependencies between parameters. The shown values may not represent
realistic usage scenarios.
The screenshots usually show a fully equipped product, that is: with all options installed. Thus, some functions shown in the screenshots may not be available in your particular product configuration.
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2 About frequency response correction
The I/Q modulation frequency response or the I/Q flatness is an important signal quality parameter for any vector signal generator, in particular when signals with large
bandwidth are generated. The I/Q modulation frequency response affects for example:
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Without any additional option, the R&S SMBV100B is equipped with a high-performance I/Q modulator that, if configured to, generates an optimized flat signal. With
activated high-quality optimization mode, the instrument uses an internal correction
method and digital baseband filters to compensate for frequency response variations
and I/Q skew within its signal processing chain. Signal correction is performed in real
time.
Component's contribution to the system flatness
The signal at the RF and analog I/Q outputs of the R&S SMBV100B is flat. However,
the DUT is rarely connected directly to the outputs of the generator. You are likely to
use connecting cables between the R&S SMBV100B and the DUT as it is likely that
the test setup includes further measurement equipment, connected at the DUT's outputs. Especially at microwave frequencies and with complex test setups, components
like cables, power combiners, switches or mixers can severely affect the I/Q flatness.
About frequency response correction
Error vector magnitude (EVM) of digitally modulated signals
Relative carrier power of multi carrier signals distributed over a large bandwidth
Figure 2-1: Effect of the non-linear frequency response in the components on the signal flatness
DUT = Device under test, whose characteristics are measured
Components
1 = Flat signal at the outputs of the signal generator R&S SMBV100B
2 =
= Designation of all components between the measurement equipment and the DUT, incl.
cables, power combiners, switches or mixers, etc.
Signal received at the analyzer R&S®FSW is affected by the degraded I/Q flatness caused by
the components. Measuring the true DUT characteristics is not feasible.
Principle of user-defined frequency response compensation
In instruments equipped with the option R&S SMBV100B-K544, you can load scattering parameters (S-parameters) files and frequency response (FR) files to compensate
also for the previous mentioned deviations.
The correction values retrieved from these files are used to pre-process the signal so
that the resulting frequency response regarding both magnitude and phase is compensated. Suitable transmission scattering parameters files can be obtained by measuring
the components with a vector network analyzer (VNA).
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In addition to the scattering parameters files or instead of them, if S-parameter files are
unavailable, correction values can also be retrieved from FR files. Suitable FR files can
be obtained with R&S NRP power sensors or through conversion of an equalizer file.
About frequency response correction
Figure 2-2: Understanding the frequency response correction
DUT = Device under test, whose characteristics are be measured
Components
1 = Characterize the transmission chain at the DUT input frequency; measure all components
2 = In the R&S SMBV100B, the baseband signal is pre-processed so that the signal at the outputs
3 = Received at the DUT input, the pre-processed signal if flat
4 = Frequency response of the DUT
5 =
6 = Characterize the transmission chain at the DUT output frequency; measure all components
7 =
8 = Resembles the DUT characteristic as it is at the DUT' output (4); thus, only the frequency
* = Frequency response or scattering parameters files
= Designation of all components between the measurement equipment and the DUT, incl.
cables, power combiners, switches or mixers, etc.
between the R&S SMBV100B and the DUT. Load and apply the collected transmission scattering parameters file in the R&S SMBV100B.
is the inverted version of the channel response
Signal at the DUT's output, as it should be received and measured with the R&S®FSW
between the DUT and the inputs of the R&S®FSW. Load and apply the collected frequency
response (or the transmission scattering parameters) file in one of the measurement instruments.
If the compensation is performed at the analyzer, the signal at the R&S®FSW input contains
the effects caused by the DUT (5) and the transmission channel (6)
response of the DUT can be analyzed
Real-time compensation
The compensation filters are implemented in hardware. Thus, corrections are applied
in real time, irrespectively of the baseband signal. If the baseband signal is reconfigured, the compensation is applied on that signal, too. Logically though, if parts of the
setup like components or cables are changed, these newly introduced parts have to be
measured and their S-parameter files included in the compensation.
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Difference between the S-parameters and FR files
The S-parameters files contain transmission scattering parameters (S-parameters)
that characterize the component's frequency response. They compensate the frequency response of the scattering parameters network, regarding magnitude and
phase, while taking reflections into consideration.
FR files in *.fres format, can contain magnitude and phase corrections but reflections are not included.
User correction or *.uco files can be used to compensate the magnitude at the cen-
ter frequency. If loaded as frequency response (FR) list, these files also compensate
the magnitude frequency response over the modulation frequency. User correction
files, however, do not contain phase or reflection correction values.
2.1 Required options
The equipment layout includes:
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About frequency response correction
Supported file formats
Base unit
Option user-defined frequency response correction (R&S SMBVB-K544)
2.2 Supported file formats
The following file formats are supported:
Extension File type Description
*.s<n>p
*.uco
*.fres
*.freqresp
2.2.1 S-parameters (Touchstone) files
The R&S SMBV100B can extract and apply scattering matrix corrections from Sparameters data files. These data files are also known as touchstone files and exist in
two format versions, V1.0 and V2.0.
R&S SMBV100B-K544 supports touchstone file format in version V1.0.
Touchstone S-parameters files See Chapter 2.2.1, "S-parameters (Touch-
User correction files See Chapter 2.2.2, "Frequency response
Frequency and phase of the transmission path in a touchstone format
Save/recall file containing configuration in the dialog
stone) files", on page 11.
(FR) files", on page 14.
See Chapter 2.2.2, "Frequency response
(FR) files", on page 14.
See "Save/Recall" on page 19.
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File extension
S-parameters files are files with predefined structure and file extension *.s<n>p,
where <n>:
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An *.s1p file, for example, contains a one-port measurement and one S-parameter
while the file *.s3p contains a three-port measurement and nine S-parameters.
The most meaningful S-parameter for the frequency response compensation is the
S21, because it characterizes the frequency response of a component.
S-parameters measurements are typically performed with a vector network analyzer,
like, for example, the R&S®ZNB.
File format
Touchstone files contain a header, a comment section, and the actual trace data.
The following is an extract of the file content of file created by the R&S®ZNB.
About frequency response correction
Supported file formats
Is an integer value and <n> ≥ 1
<n> = number of measured ports
<n>2 = number of S-parameters the file contains
# HZ S RI R 50.00
! Rohde & Schwarz Vector Network Analyzer
! Rohde-Schwarz,ZNB8-4Port,1311601044100005,1.93.1.42
! Created: UTC 9/17/2013, 9:13:56 AM
! freq[Hz] re:S11 im:S11
1.000000000000000E5 -4.897128641605377E-1 3.767784312367439E-2
4.259950000000000E7 -5.450598597526550E-1 3.608805686235428E-2
...
# indicates the beginning of the header line. It is required at the top of file and consists
of the following data elements:
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<Frequency unit>: HZ / KHZ / MHZ / GHZ, Rohde & Schwarz analyzers usually
use Hz.
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<Data file type>: S for S-parameter files
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<Data format>:
– RI = Re/Im
– MA = linear magnitude-phase
– DB = Mag-Phase in decibels
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<Reference resistance>: specifies the impedance system underlying the trace
data, given as a real, positive resistance (default 50 Ω)
Comment lines start with the exclamation mark (!) and can contain any text used for
documentation of the trace data file. Any number of comment lines can be inserted
before or after the header line.
The following information is displayed in the comments section:
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VNA identification (comment line 2 in above example)
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Timestamp (comment line 3)
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The trace data section corresponds to a set of single-ended S-parameters. It depends
on the number of ports and the data format.
For real and imaginary values (<Data format> = RI) the trace data for each stimulus
frequency is arranged as indicated in the lowermost comment lines:
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About frequency response correction
Supported file formats
Port-specific renormalization information (comment lines 4ff, if applied)
Headings for included data tables (comment lines right above the data tables, starting with ! freq)
1-port files (*.s1p)
! freq[Hz] re:S11 im:S11
S11 can be replaced by any S-parameter.
Thus, the *.s1p format can contain an arbitrary data trace representing an Sparameter.
2-port files (*.s2p)
! freq[Hz] re:S11 im:S11 re:S21 im:S21 re:S12 im:S12 re:
S22 im:S22
(all values arranged in 1 line)
n-port files (*.snp), 2 < n ≤ 4
! freq[Hz] re:S11 im:S11 re:S12 im:S12 ... re:S1n im:S1n
! re:S21 im:S21 re:S22 im:S22 ... re:S2n im:S2n
! ...
! re:Sn1 im:Sn1 re:Sn2 im:Sn2 ... re:Snn im:Snn
(values arranged in n lines)
n-port files (*.snp), n > 4
! freq[Hz] re:S11 im:S11 ... re:S14 im:S14
! re:S15 im:S15 ...
! ...
! ... re:Snn im:Snn
(values arranged in m = ⌈n2/4⌉ lines, where the first m-1 data lines contain exactly
four value pairs)
The stimulus frequencies are arranged in ascending order. For linear magnitude-phase
and magnitude-phase in decibels values (<Data format> = MA or DB), the trace data
the real and imaginary S-parameter values re:Sij im:Sij are replaced by
mag:Sij ang:Sij or db:Sij ang:Sij, respectively.
Cascading files
If several S-parameter files are loaded, they are cascaded. Each S-parameters file is
defined with its origin and destination ports. Thus, you can configure or reverse the orientation of the signal chain.
The first entry in the chain is the R&S SMBV100B itself; it illustrates the chain orientation - form R&S SMBV100B toward the DUT.
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