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R&S ® FPS-K70
Vector Signal Analysis
User Manual
(;Úã@2)
1176.8516.02 ─ 06
This manual applies to the following R&S ® FPS models with firmware version 1.30 and higher:
● R&S
® FPS4 (1319.2008K04)
● R&S ® FPS7 (1319.2008K07)
● R&S ® FPS13 (1319.2008K13)
● R&S ® FPS30 (1319.2008K30)
● R&S ® FPS40 (1319.2008K40)
The following firmware options are described:
● R&S FPS-K70 (1321.4127.02)
The firmware of the instrument makes use of several valuable open source software packages. For information, see the "Open
Source Acknowledgement" on the user documentation CD-ROM (included in delivery).
Rohde & Schwarz would like to thank the open source community for their valuable contribution to embedded computing.
© 2015 Rohde & Schwarz GmbH & Co. KG
Mühldorfstr. 15, 81671 München, Germany
Phone: +49 89 41 29 - 0
Fax: +49 89 41 29 12 164
E-mail: [email protected]
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.
The following abbreviations are used throughout this manual: R&S ® FPS is abbreviated as R&S FPS.
R&S ® FPS-K70 Contents
Contents
1 Preface.................................................................................................... 7
1.1
1.2
1.3
2 Welcome to the Vector Signal Analysis Application........................ 10
2.1
2.2
3 Measurements and Result Displays...................................................14
3.1
3.2
3.3
4 Measurement Basics........................................................................... 56
4.1
Filters and Bandwidths During Signal Processing..................................................56
4.2
4.3
4.4
4.5
Signal Model, Estimation and Modulation Errors.................................................. 100
4.6
4.7
Display Points vs Estimation Points per Symbol.................................................. 121
4.8
4.9
Known Data Files - Dependencies and Restrictions............................................. 123
4.10
5 Configuration......................................................................................127
5.1
5.2
5.3
5.4
5.5
5.6
5.7
User Manual 1176.8516.02 ─ 06 3
R&S ® FPS-K70 Contents
5.8
5.9
5.10
5.11
5.12
6 Analysis.............................................................................................. 190
6.1
6.2
6.3
6.4
6.5
6.6
7 I/Q Data Import and Export................................................................206
7.1
7.2
8 How to Perform Vector Signal Analysis...........................................210
8.1
How to Perform VSA According to Digital Standards........................................... 210
8.2
How to Perform Customized VSA Measurements................................................. 212
8.3
9 Measurement Examples.................................................................... 228
9.1
9.2
Measurement Example 1: Continuous QPSK Signal............................................. 228
9.3
Measurement Example 2: Burst GSM EDGE Signals............................................ 235
10 Optimizing and Troubleshooting the Measurement....................... 244
10.1
10.2
10.3
10.4
11 Remote Commands for VSA............................................................. 264
11.1
11.2
User Manual 1176.8516.02 ─ 06 4
R&S ® FPS-K70 Contents
11.3
11.4
11.5
11.6
11.7
11.8
11.9
11.10
11.11
11.12
11.13
A Annex.................................................................................................. 411
A.1
A.2
A.3
A.4
A.5
A.6
A.7
List of Remote Commands (VSA).....................................................446
Index....................................................................................................456
User Manual 1176.8516.02 ─ 06 5
R&S ® FPS-K70 Contents
User Manual 1176.8516.02 ─ 06 6
R&S ® FPS-K70 Preface
About this Manual
1 Preface
1.1 About this Manual
This R&S FPS Vector Signal Analysis User Manual provides all the information spe-
cific 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 measurement results and the tasks required to obtain them. The following topics are included:
● Welcome to the VSA Application
Introduction to and getting familiar with the application
● Typical applications
Example measurement scenarios in which the application is frequently used.
● Measurements and Result Displays
Details on supported measurements and their result types
● Measurement Basics
Background information on basic terms and principles in the context of the measurement
● Configuration + Analysis
A concise description of all functions and settings available to configure measurements and analyze results with their corresponding remote control command
● I/Q Data Import and Export
Description of general functions to import and export raw I/Q (measurement) data
● How to Perform Measurements in VSA
The basic procedure to perform each measurement and step-by-step instructions for more complex tasks or alternative methods
● Measurement Examples
Detailed measurement examples to guide you through typical measurement scenarios and allow you to try out the application immediately
● Optimizing and Troubleshooting the Measurement
Hints and tips on how to handle errors and optimize the test setup
● Remote Commands for VSA
Remote commands required to configure and perform VSA 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)
Programming examples demonstrate the use of many commands and can usually be executed directly for test purposes
● Annex
Reference material
● List of remote commands
Alpahabetical list of all remote commands described in the manual
User Manual 1176.8516.02 ─ 06 7
R&S ® FPS-K70 Preface
Documentation Overview
● Index
1.2 Documentation Overview
The user documentation for the R&S FPS consists of the following parts:
● Printed Getting Started manual
● Online Help system on the instrument
● Documentation CD-ROM with:
– Getting Started
– User Manuals for base unit and firmware applications
– Service Manual
– Release Notes
– Data sheet and product brochures
Online Help
The Online Help is embedded in the instrument's firmware. It offers quick, context-sensitive access to the complete information needed for operation and programming.
Online help is available using the icon on the toolbar of the R&S FPS.
Getting Started
This manual is delivered with the instrument in printed form and in PDF format on the
CD-ROM. It provides the information needed to set up and start working with the instrument. Basic operations and handling are described. Safety information is also included.
The Getting Started manual in various languages is also available for download from the Rohde & Schwarz website, on the R&S FPS product page at http://www.rohdeschwarz.com/product/FPS.html
.
User Manuals
User manuals are provided for the base unit and each additional (firmware) application.
The user manuals are available in PDF format - in printable form - on the Documentation CD-ROM delivered with the instrument. In the user manuals, all instrument functions are described in detail. Furthermore, they provide a complete description of the remote control commands with programming examples.
The user manual for the base unit provides basic information on operating the
R&S FPS in general, and the Spectrum application in particular. Furthermore, the software functions that enhance the basic functionality for various applications are described here. An introduction to remote control is provided, as well as information on maintenance, instrument interfaces and troubleshooting.
In the individual application manuals, the specific instrument functions of the application are described in detail. For additional information on default settings and parame-
User Manual 1176.8516.02 ─ 06 8
R&S ® FPS-K70 Preface
Typographical Conventions ters, refer to the data sheets. Basic information on operating the R&S FPS is not included in the application manuals.
All user manuals are also available for download from the Rohde & Schwarz website, on the R&S FPS product page at http://www2.rohde-schwarz.com/product/FPS.html
.
Service Manual
This manual is available in PDF format on the Documentation CD-ROM delivered with the instrument. It describes how to check compliance with rated specifications, instrument function, repair, troubleshooting and fault elimination. It contains all information required for repairing the R&S FPS by replacing modules.
Release Notes
The release notes describe the installation of the firmware, new and modified functions, eliminated problems, and last minute changes to the documentation. The corresponding firmware version is indicated on the title page of the release notes.
The most recent release notes are also available for download from the Rohde &
Schwarz website, on the R&S FPS product page at http://www2.rohde-schwarz.com/ product/FPS.html
> Downloads > Firmware.
1.3 Typographical Conventions
The following text markers are used throughout this documentation:
Convention
"Graphical user interface elements"
KEYS
File names, commands, program code
Input
"References"
Description
All names of graphical user interface elements on the screen, such as dialog boxes, menus, options, buttons, and softkeys are enclosed by quotation marks.
Key names are written in capital letters.
File names, commands, coding samples and screen output are distinguished by their font.
Input to be entered by the user is displayed in italics.
Links that you can click are displayed in blue font.
References to other parts of the documentation are enclosed by quotation marks.
User Manual 1176.8516.02 ─ 06 9
R&S ® FPS-K70 Welcome to the Vector Signal Analysis Application
Starting the VSA Application
2 Welcome to the Vector Signal Analysis
Application
The R&S FPS-K70 is a firmware application that adds functionality to perform Vector
Signal Analysis (VSA) to the R&S FPS.
The R&S FPS VSA application performs vector and scalar measurements on digitally modulated single-carrier signals. To perform the measurements it converts RF signals into the complex baseband. Use of an optional external mixer is also supported.
The R&S FPS VSA application features:
● Flexible modulation analysis from MSK to 1024QAM
● Numerous standard-specific default settings
● Various graphical, numerical and statistical evaluations and result displays
● Spectrum analyses of the measurement and error signal
● Flexible burst search for the analysis of complex signal combinations, short bursts or signal mix
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 Spectrum application and are described in the R&S FPS User Manual. The latest version is available for download at the product homepage
(http://www2.rohde-schwarz.com/product/FPS.html) .
Installation
You can find detailed installation instructions in the R&S FPS Getting Started manual or in the Release Notes.
2.1 Starting the VSA Application
The VSA application adds a new application to the R&S FPS.
Manual operation via an external monitor and mouse
Although the R&S FPS does not have a built-in display, it is possible to operate it interactively in manual mode using a graphical user interface with an external monitor and a mouse connected.
It is recommended that you use the manual mode initially to get familiar with the instrument and its functions before using it in pure remote mode. Thus, this document describes in detail how to operate the instrument manually using an external monitor and mouse. The remote commands are described in the second part of the document.
For details on manual operation see the R&S FPS Getting Started manual.
User Manual 1176.8516.02 ─ 06 10
R&S ® FPS-K70 Welcome to the Vector Signal Analysis Application
Understanding the Display Information
To activate the VSA application
1. Select the MODE key.
A dialog box opens that contains all operating modes and applications currently available on your R&S FPS.
2. Select the "VSA" item.
The R&S FPS opens a new measurement channel for the VSA application.
The measurement is started immediately with the default settings. It can be configured in the VSA "Overview" dialog box, which is displayed when you select the "Overview"
softkey from any menu (see chapter 5.3, "Configuration Overview" , on page 132).
Multiple Measurement Channels and Sequencer Function
When you activate an application, a new measurement channel is created which determines the measurement settings for that application. The same application can be activated with different measurement settings by creating several channels for the same application.
The number of channels that can be configured at the same time depends on the available memory on the instrument.
Only one measurement can be performed at any time, namely the one in the currently active channel. However, in order to perform the configured measurements consecutively, a Sequencer function is provided.
If activated, the measurements configured in the currently active channels are performed one after the other in the order of the tabs. The currently active measurement is indicated by a symbol in the tab label. The result displays of the individual channels are updated in the tabs (as well as the "MultiView") as the measurements are performed. Sequential operation itself is independent of the currently displayed tab.
For details on the Sequencer function see the R&S FPS User Manual.
2.2 Understanding the Display Information
The following figure shows a measurement diagram during analyzer operation. All different information areas are labeled. They are explained in more detail in the following sections.
User Manual 1176.8516.02 ─ 06 11
R&S ® FPS-K70 Welcome to the Vector Signal Analysis Application
Understanding the Display Information
1 = Channel bar for firmware and measurement settings
2+3 = Window title bar with diagram-specific (trace) information
4 = Diagram area
5 = Diagram footer with diagram-specific information, depending on measurement application
6 = Instrument status bar with error messages, progress bar and date/time display
MSRA operating mode
In MSRA operating mode, additional tabs and elements are available. A colored background of the screen behind the measurement channel tabs indicates that you are in
MSRA operating mode.
For details on the MSRA operating mode see the R&S FPS MSRA User Manual.
Channel bar information
In VSA application, the R&S FPS shows the following settings:
Table 2-1: Information displayed in the channel bar in VSA application
Ref Level Reference level
Freq Center frequency for the RF signal
Std
Res Len
SR
Att
Offset
Cap Len
Selected measurement standard or modulation type (if no standard selected)
Result Length
Symbol Rate
Mechanical and electronic RF attenuation
Reference level offset
Capture Length (instead of result length for capture buffer display), see
"Capture Length Settings" on page 156
User Manual 1176.8516.02 ─ 06 12
R&S ® FPS-K70 Welcome to the Vector Signal Analysis Application
Understanding the Display Information
Input
Burst
Pattern
Stat Count
Capt Count
SGL
Input type of the signal source, see
chapter 5.5.1, "Input Settings" , on page 142
Burst search active (see "Enabling Burst Searches" on page 165)
Pattern search active (see
"Enabling Pattern Searches" on page 167)
Statistics count for averaging and other statistical operations, see
"Statistic Count" on page 162; cannot be edited directly
Capture count; the current number of captures performed if several captures are necessary to obtain the number of results defined by "Statistics
Count"; cannot be edited directly
The sweep is set to single sweep mode.
In addition, the channel bar also displays information on instrument settings that affect the measurement results even though this is not immediately apparent from the display of the measured values (e.g. transducer or trigger settings). This information is displayed only when applicable for the current measurement. For details see the
R&S FPS Getting Started manual.
Window title bar information
For each diagram, the header provides the following information:
Fig. 2-1: Window title bar information in VSA application
1 = Window name
2 = Result type
3 = Data source type
4 = Trace color
5 = Displayed signal for Meas&Ref data source: M (Meas) or R (Ref)
6 = Trace mode
Diagram area
The diagram area displays the results according to the selected result displays (see
chapter 3, "Measurements and Result Displays" , on page 14).
Diagram footer information
The diagram footer (beneath the diagram) contains the start and stop symbols or time of the evaluation range.
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.
User Manual 1176.8516.02 ─ 06 13
R&S ® FPS-K70 Measurements and Result Displays
Evaluation Data Sources in VSA
3 Measurements and Result Displays
Various different result displays for VSA measurements are available. Which result types are available depends on the selected data source. You can define which part of the measured signal is to be evaluated and displayed.
The determined result and evaluation ranges are included in the result displays (where useful) to visualize the basis of the displayed values and traces.
For background information on the result and evaluation ranges see
chapter 4.6, "Measurement Ranges" , on page 116.)
3.1 Evaluation Data Sources in VSA
All data sources for evaluation available for VSA are displayed in the evaluation bar in
SmartGrid mode.
The data source determines which result types are available (see
). For details on selecting the data source for evaluation see
chapter 6.5, "Display and Window Configuration" , on page 201.
In diagrams in the frequency domain (Spectrum transformation, see
Transformation" on page 202) the usable I/Q bandwidth is indicated by vertical blue
lines.
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R&S ® FPS-K70 Measurements and Result Displays
Evaluation Data Sources in VSA
Capture Buffer
The captured I/Q data
In capture buffer result diagrams the result ranges are indicated by green bars along the time axis. The currently displayed result range is indicated by a blue bar.
Fig. 3-1: Result ranges for a burst signal
Note: You can use the capture buffer display to navigate through the available result
ranges (using Select Result Rng
function), and analyze the individual result ranges in separate windows.
You can change the position of the result range quickly and easily by dragging the blue bar representing the result range to a different position in the capture buffer.
The default result type is "Magnitude Absolute".
The following result types are available:
●
chapter 3.2.21, "Magnitude Absolute" , on page 39
●
chapter 3.2.22, "Magnitude Overview Absolute" , on page 40
●
chapter 3.2.28, "Real/Imag (I/Q)" , on page 46
●
chapter 3.2.11, "Frequency Absolute" , on page 29
●
chapter 3.2.32, "Vector I/Q" , on page 53
Remote command:
LAY:ADD? '1',BEL,TCAP(see LAYout:ADD[:WINDow]?
Measurement & Reference Signal
The measurement signal or the ideal reference signal (or both)
The default result type is "Magnitude Relative".
The following result types are available:
●
chapter 3.2.21, "Magnitude Absolute" , on page 39
●
chapter 3.2.23, "Magnitude Relative" , on page 42
●
chapter 3.2.26, "Phase Wrap" , on page 44
●
chapter 3.2.27, "Phase Unwrap" , on page 45
●
chapter 3.2.11, "Frequency Absolute" , on page 29
●
chapter 3.2.12, "Frequency Relative" , on page 31
●
chapter 3.2.28, "Real/Imag (I/Q)" , on page 46
User Manual 1176.8516.02 ─ 06 15
R&S ® FPS-K70 Measurements and Result Displays
Evaluation Data Sources in VSA
●
chapter 3.2.10, "Eye Diagram Real (I)" , on page 29
●
chapter 3.2.9, "Eye Diagram Imag (Q)" , on page 28
●
chapter 3.2.8, "Eye Diagram Frequency" , on page 27
●
chapter 3.2.5, "Constellation I/Q" , on page 24
●
chapter 3.2.32, "Vector I/Q" , on page 53
●
chapter 3.2.4, "Constellation Frequency" , on page 23
●
chapter 3.2.31, "Vector Frequency" , on page 52
Remote command:
LAY:ADD? '1',BEL,REF(see LAYout:ADD[:WINDow]?
Symbols
The detected symbols (i.e. the detected bits) displayed in a table;
The default result type is a hexadecimal symbol table.
Other formats for the symbol table are available, but no other result types (see
chapter 3.2.30, "Symbol Table" , on page 51).
Remote command:
LAY:ADD? '1',BEL, SYMB(see LAYout:ADD[:WINDow]?
Error Vector
The modulated difference between the complex measurement signal and the complex reference signal:
Modulation (measurement signal - reference signal)
For example: EVM = Mag(meas - ref)
The default result type is "EVM".
The following result types are available:
●
chapter 3.2.7, "Error Vector Magnitude (EVM)" , on page 26
●
chapter 3.2.28, "Real/Imag (I/Q)" , on page 46
●
chapter 3.2.32, "Vector I/Q" , on page 53
Remote command:
LAY:ADD? '1',BEL,EVEC(see LAYout:ADD[:WINDow]?
Modulation Errors
The difference between the modulated complex samples in the measurement and the modulated reference signal:
Modulation (measurement signal) - Modulation (reference signal)
For example: Magnitude Error = Mag(meas) - Mag(ref)
The default result type is "Magnitude Error".
The following result types are available:
●
chapter 3.2.21, "Magnitude Absolute" , on page 39
●
chapter 3.2.25, "Phase Error" , on page 43
●
chapter 3.2.13, "Frequency Error Absolute" , on page 32
●
chapter 3.2.14, "Frequency Error Relative" , on page 33
Remote command:
LAY:ADD? '1',BEL,MERR(see LAYout:ADD[:WINDow]?
User Manual 1176.8516.02 ─ 06 16
R&S ® FPS-K70 Measurements and Result Displays
Evaluation Data Sources in VSA
Modulation Accuracy
Paraeters that characterize the accuracy of modulation.
The default result type is "Result Summary".
The following result types are available:
●
chapter 3.2.29, "Result Summary" , on page 47
●
chapter 3.2.1, "Bit Error Rate (BER)" , on page 20
The results of a modulation accuracy measurement can be checked for violation of defined limits automatically. If limit check is activated and the measured values exceed the limits, those values are indicated in red in the result summary table. If limit check is activated and no values exceed the limits, the checked values are indicated in green.
Remote command:
LAY:ADD? '1',BEL,MACC(see LAYout:ADD[:WINDow]?
Equalizer
Filter characteristics of the equalizer used to compensate for channel distortion and parameters of the distortion itself.
The following result types are available:
●
chapter 3.2.18, "Impulse Response Magnitude" , on page 37
●
chapter 3.2.19, "Impulse Response Phase" , on page 38
●
chapter 3.2.20, "Impulse Response Real/Imag" , on page 38
●
chapter 3.2.16, "Frequency Response Magnitude" , on page 35
●
chapter 3.2.17, "Frequency Response Phase" , on page 36
●
chapter 3.2.15, "Frequency Response Group Delay" , on page 34
●
chapter 3.2.3, "Channel Frequency Response Magnitude" , on page 22
●
chapter 3.2.2, "Channel Frequency Response Group Delay" , on page 22
The default result type is "Frequency Response Magnitude".
Remote command:
LAY:ADD? '1',BEL,EQU(see LAYout:ADD[:WINDow]?
User Manual 1176.8516.02 ─ 06 17
R&S ® FPS-K70 Measurements and Result Displays
Result Types in VSA
3.2 Result Types in VSA
The available result types for a window depend on the selected evaluation data source.
The SCPI parameters in the following table refer to the CALC:FORM command, see
CALCulate<n>:FORMat on page 366.
Table 3-1: Available result types depending on data source
Evaluation Data
Source
Result Type SCPI Parameter
Capture Buffer Magnitude Absolute MAGNitude
Meas & Ref Signal
Real/Imag (I/Q)
Frequency Absolute
Vector I/Q
Magnitude Overview Absolute
Magnitude Absolute
Magnitude Relative
RIMag
FREQuency
COMP
MOVerview
MAGNitude
MAGNitude
Phase Wrap
Phase Unwrap
Frequency Absolute
Frequency Relative
Real/Imag (I/Q)
Eye Diagram Real (I)
Eye Diagram Imag (Q)
Eye Diagram Frequency
PHASe
UPHase
FREQuency
FREQuency
RIMag
IEYE
QEYE
FEYE
Symbols
Error Vector
Constellation I/Q
Constellation I/Q (Rotated)
Vector I/Q
Constellation Frequency
Vector Frequency
Binary
Octal
Decimal
Hexadecimal
EVM
Real/Imag (I/Q)
-
-
-
-
CONS
RCON
COMP
CONF
COVF
MAGNitude
RIMag
User Manual 1176.8516.02 ─ 06 18
R&S ® FPS-K70 Measurements and Result Displays
Result Types in VSA
Evaluation Data
Source
Modulation Errors
Equalizer
Multi Source
Result Type
Vector I/Q
Magnitude Error
Phase Error
Frequency Error Absolute
Frequency Error Relative
Modulation Accuracy Bit Error Rate
Result Summary
Impulse Response Magnitude
SCPI Parameter
COMP
MAGNitude
PHASe
FREQuency
FREQuency
BERate
RSUM
MAGNitude
Impulse Response Phase
Impulse Response Real/Image
Frequency Response Magnitude
Frequency Response Phase
UPHase
RIMag
MAGNitude
UPHase
Frequency Response Group Delay
Channel Frquency Response Magnitude
GDELay
MAGNitude
Channel Frequency Response Group
Delay
GDELay
Spectrum (Real/Imag) (Capture buffer
+ Error)
RIMag (query only)
Spectrum (Real/Imag) (Measurement
+ Error)
RIMag (query only)
For details on selecting the data source and result types for evaluation see
"Display and Window Configuration" , on page 201.
Remote command:
CALCulate<n>:FORMat on page 366
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R&S ® FPS-K70 Measurements and Result Displays
Result Types in VSA
3.2.1 Bit Error Rate (BER)
A bit error rate (BER) measurement compares the transmitted bits with the determined symbol decision bits:
BER = error bits / number of analyzed bits
As a prerequisite for this measurement, the VSA application must know which bit sequences are correct, i.e. which bit sequences may occur. This knowledge must be provided as a list of possible data sequences in xml format, which is loaded in the VSA
application (see chapter 4.9, "Known Data Files - Dependencies and Restrictions" , on page 123).
Auxiliary tool to create Known Data files
An auxiliary tool to create Known Data files from data that is already available in the
VSA application is provided on the instrument free of charge.
See
chapter 8.2.3.2, "How to Create Known Data Files" , on page 219.
If such a file is loaded in the application, the BER result display is available.
Available for source types:
● Modulation Accuracy
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R&S ® FPS-K70 Measurements and Result Displays
Result Types in VSA
Note that this measurement may take some time, as each symbol decision must be compared to the possible data sequences one by one.
The BER measurement is an indicator for the quality of the demodulated signal. High
BER values indicate problems such as:
● inadequate demodulation settings
● poor quality in the source data
● false or missing sequences in the Known Data file
● result range alignment leads to a mismatch of the input data with the defined sequences
A BER value of 0.5 means that for at least one measurement no matching sequence was found.
See also
chapter 4.4.3, "Demodulation and Symbol Decisions" , on page 93
The following information is provided in the BER result display:
● Bit Error Rate: error bits / number of analyzed bits
● Total # of Errors: number of detected bit errors (known data compared to symbol decisions)
● Total # of Bits: number of analyzed bits
For each of these results, the following values are provided:
BER Result
Current
Minimum
Maximum
Accumulative
Description
Value for current result range
Minimum "Current" value during the current measurement
Maximum "Current" value during the current measurement
Total value over several measurements; for BER: Total # of Errors / Total # of Bits (similar to average function)
Remote commands:
LAY:ADD? '1',BEL,MACC
to define the required source type (see LAYout:ADD[:WINDow]?
CALC:FORM BER to define the result type (see
CALCulate<n>:FORMat on page 366)
CALC:BER?
to query the results (see CALCulate<n>:BERate on page 378)
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R&S ® FPS-K70 Measurements and Result Displays
Result Types in VSA
3.2.2 Channel Frequency Response Group Delay
The Frequency Response Group Delay of the channel is the derivation of phase over frequency for the original input signal. It is a measure of phase distortion.
Remote commands:
LAY:ADD? '1',BEL,EQU
to define the required source type (see LAYout:ADD[:WINDow]?
CALC:FEED 'XFR:DDEM:IRAT'
to define the channel frequency response result type (see CALCulate<n>:FEED on page 365)
CALC:FORM GDEL
to define the group delay result type (see CALCulate<n>:FORMat on page 366)
TRAC:DATA? TRACE1 to query the trace results (see
and
3.2.3 Channel Frequency Response Magnitude
The frequency response magnitude of the channel indicates which distortions occurred during transmission of the input signal. It is only determined if the equalizer is activated.
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R&S ® FPS-K70 Measurements and Result Displays
Result Types in VSA
The bandwidth for which the channel transfer function can be estimated is not only limited by the usable I/Q bandwidth, but also by the bandwidth of the analyzed input signal. Areas with low reception power, e.g. at the filter edges, may suffer from less accurate estimation results.
Remote commands:
LAY:ADD? '1',BEL,EQU
to define the required source type (see LAYout:ADD[:WINDow]?
CALC:FEED 'XFR:DDEM:IRAT'
to define the channel frequency response result type (see CALCulate<n>:FEED on page 365)
CALC:FORM MAGN to define the magnitude result type (see
CALCulate<n>:FORMat on page 366)
TRAC:DATA? TRACE1 to query the trace results (see
and
3.2.4 Constellation Frequency
The instantaneous frequency of the source signal (without inter-symbol interference) as an X/Y plot; only the symbol decision instants are drawn and not connected.
Available for source types:
● Meas & Ref Signal
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Fig. 3-2: Result display "Constellation Frequency"
Remote commands:
LAY:ADD? '1',BEL,MEAS
to define the required source type (see LAYout:ADD[:WINDow]?
CALC:FORM CONF to define the result type (see
CALCulate<n>:FORMat on page 366)
TRAC:DATA? TRACE1 to query the trace results (see
and
"Polar Diagrams" , on page 376)
3.2.5 Constellation I/Q
The complex source signal (without inter-symbol interference) as an X/Y plot; only the
(de-rotated) symbol decision instants are drawn and not connected
Available for source types:
● Meas & Ref Signal
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Fig. 3-3: Constellation I/Q diagram for QPSK modulated signal
Remote commands:
LAY:ADD? '1',BEL,MEAS
to define the required source type (see LAYout:ADD[:WINDow]?
CALC:FORM CONS to define the result type (see
CALCulate<n>:FORMat on page 366)
TRAC:DATA? TRACE1 to query the trace results (see
and
"Polar Diagrams" , on page 376)
3.2.6 Constellation I/Q (Rotated)
The complex source signal as an X/Y plot; As opposed to the common Constellation
I/Q display, the symbol decision instants, including the rotated ones, are drawn and not connected.
Available for source types:
● Meas & Ref Signal
This result type is only available for signals with a rotating modulation.
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Fig. 3-4: Result display "Constellation I/Q (Rotated)" vs. common "Constellation I/Q" for 3 π/4-QPSK modulation
Remote commands:
LAY:ADD? '1',BEL,MEAS
to define the required source type (see LAYout:ADD[:WINDow]?
CALC:FORM RCON to define the result type (see
CALCulate<n>:FORMat on page 366)
TRAC:DATA? TRACE1 to query the trace results (see
and
"Polar Diagrams" , on page 376)
3.2.7 Error Vector Magnitude (EVM)
Displays the error vector magnitude as a function of symbols or time.
EVM
EV
C with t=n ·T
D
and T
D
=the duration of one sampling period at the sample rate defined by the display points per symbol parameter (see
"Display Points/Sym" on page 203).
The normalization constant C is chosen according to the EVM normalization. By default C² is the mean power of the reference signal.
C
1
K
k
REF
2 and
T duration of symbol periods
Note that k=0.5
·n·T for Offset QPSK with inactive Offset EVM.
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Fig. 3-5: Result display "Error Vector Magnitude"
Available for source types:
● Error Vector
Remote commands:
LAY:ADD? '1',BEL,EVEC
to define the required source type (see LAYout:ADD[:WINDow]?
CALC:FORM MAGN to define the result type (see
CALCulate<n>:FORMat on page 366)
TRAC:DATA? TRACE1 to query the trace results (see
and
"Cartesian Diagrams" , on page 376)
3.2.8 Eye Diagram Frequency
The eye diagram of the currently measured frequencies and/or the reference signal.
The time span of the data depends on the evaluation range (capture buffer).
Available for source types:
● Meas & Ref Signal
Remote commands:
LAY:ADD? '1',BEL,MEAS
to define the required source type (see LAYout:ADD[:WINDow]?
CALC:FORM FEYE
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Result Types in VSA to define the result type (see
CALCulate<n>:FORMat on page 366)
TRAC:DATA? TRACE1 to query the trace results (see
and
"Cartesian Diagrams" , on page 376)
3.2.9 Eye Diagram Imag (Q)
The eye pattern of the quadrature (Q) channel; the x-axis range is from -1 to +1 symbols (MSK: -2 to +2)
Available for source types:
● Meas & Ref Signal
Fig. 3-6: Result display "Eye Diagram Imag (Q)"
Remote commands:
LAY:ADD? '1',BEL,MEAS
to define the required source type (see LAYout:ADD[:WINDow]?
CALC:FORM QEYE to define the result type (see
CALCulate<n>:FORMat on page 366)
TRAC:DATA? TRACE1 to query the trace results (see
and
"Cartesian Diagrams" , on page 376)
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3.2.10 Eye Diagram Real (I)
The eye pattern of the inphase (I) channel; the x-axis value range is from -1 to +1 symbols (MSK: -2 to +2)
Available for source types:
● Meas & Ref Signal
Fig. 3-7: Result display "Eye Diagram Real (I)"
Remote commands:
LAY:ADD? '1',BEL,MEAS
to define the required source type (see LAYout:ADD[:WINDow]?
CALC:FORM IEYE to define the result type (see
CALCulate<n>:FORMat on page 366)
TRAC:DATA? TRACE1 to query the trace results (see
and
"Cartesian Diagrams" , on page 376)
3.2.11 Frequency Absolute
The instantaneous frequency of the signal source; the absolute value is displayed in
Hz.
Available for source types:
● Meas & Ref Signal
● Capture Buffer
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Meas&Ref signal:
FREQ
MEAS
2
1
d dt
MEAS with t=n ·T
D
and T
D
=the duration of one sampling period at the sample rate defined by the display points per symbol parameter (see
"Display Points/Sym" on page 203).
Capture buffer:
FREQ
CAPT .
2
1
d dt
Capt
When evaluating the capture buffer, the absolute frequency is derived from the measured phase, with T
D
=the duration of one sampling period at the sample rate (see
Note that this result display is based on an individual capture buffer range. If more than
256,000 samples are captured, overlapping ranges with a size of 256,000 each are created. Only one range at a time can be displayed in the Frequency Absolute result display. For details see
chapter 4.8, "Capture Buffer Display" , on page 122.
This measurement is mainly of interest when using the MSK or FSK modulation, but can also be used for the PSK/QAM modulations. However, since these modulations can have transitions through zero in the I/Q plane, in this case you might notice uncritical spikes. This is due to the fact that the phase of zero (or a complex value close to zero) is of limited significance, but still influences the result of the instantaneous frequency measurement.
Fig. 3-8: Result display "Frequency Absolute"
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Remote commands:
LAY:ADD? '1',BEL,MEAS
to define the required source type (see LAYout:ADD[:WINDow]?
CALC:FORM FREQ to define the result type (see
CALCulate<n>:FORMat on page 366)
TRAC:DATA? TRACE1 to query the trace results (see
and
"Capture Buffer Results" , on page 375/
chapter 11.9.2.2, "Cartesian Diagrams" , on page 376)
3.2.12 Frequency Relative
The instantaneous frequency of the signal source.
The results are normalized to the symbol rate (PSK and QAM modulated signals), the estimated FSK deviation (FSK modulated signals) or one quarter of the symbol rate
(MSK modulated signals).
FREQ
MEAS
2
1
d dt
MEAS with t=n ·T
D
and T
D
=the duration of one sampling period at the sample rate defined by the display points per symbol parameter (see
"Display Points/Sym" on page 203).
This measurement is mainly of interest when using the MSK or FSK modulation, but can also be used for the PSK/QAM modulations. See also the note for
"Frequency Absolute" , on page 29.
Available for source types:
● Meas & Ref Signal
Fig. 3-9: Result display "Frequency Relative"
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Remote commands:
LAY:ADD? '1',BEL,MEAS
to define the required source type (see LAYout:ADD[:WINDow]?
CALC:FORM FREQ to define the result type (see
CALCulate<n>:FORMat on page 366)
DISP:TRAC:Y:MODE REL
to define relative values (see DISPlay[:WINDow<n>]:TRACe<t>:Y[:SCALe]:
TRAC:DATA? TRACE1 to query the trace results (see
and
"Cartesian Diagrams" , on page 376)
3.2.13 Frequency Error Absolute
Displays the error of the instantaneous frequency in Hz of the measurement signal with respect to the reference signal as a function of symbols over time.
FREQ _ ERR
FREQ
MEAS
FREQ
REF with t=n ·T
D
and T
D
=the duration of one sampling period at the sample rate defined by the display points per symbol parameter (see
"Display Points/Sym" on page 203).
Note that this measurement does not consider a possible carrier frequency offset. This has already been compensated for in the measurement signal.
This measurement is mainly of interest when using the MSK or FSK modulation, but can also be used for the PSK/QAM modulations. However, since these modulations can have transitions through zero in the I/Q plane, in this case you might notice uncritical spikes. This is due to the fact that the phase of zero (or a complex value close to zero) has in fact limited significance, but still influences the result of the current frequency measurement.
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Fig. 3-10: Result display "Frequency Error Absolute"
Available for source types:
● Modulation Errors
Remote commands:
LAY:ADD? '1',BEL,MERR
to define the required source type (see LAYout:ADD[:WINDow]?
CALC:FORM FREQ to define the result type (see
CALCulate<n>:FORMat on page 366)
TRAC:DATA? TRACE1 to query the trace results (see
and
"Cartesian Diagrams" , on page 376)
3.2.14 Frequency Error Relative
Displays the error of the instantaneous frequency of the measurement signal with respect to the reference signal as a function of symbols over time.
The results are normalized to the symbol rate (PSK and QAM modulated signals), the estimated FSK deviation (FSK modulated signals) or one quarter of the symbol rate
(MSK modulated signals).
FREQ _ ERR
FREQ
MEAS
FREQ
REF with t=n ·T
D
and T
D
=the duration of one sampling period at the sample rate defined by the display points per symbol parameter (see
"Display Points/Sym" on page 203).
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This measurement is mainly of interest when using the MSK or FSK modulation, but can also be used for the PSK/QAM modulations. See also the note for
"Frequency Error Absolute" , on page 32.
Fig. 3-11: Result display "Frequency Error Relative"
Available for source types:
● Modulation Errors
Remote commands:
LAY:ADD? '1',BEL,MERR
to define the required source type (see LAYout:ADD[:WINDow]?
CALC:FORM FREQ to define the result type (see
CALCulate<n>:FORMat on page 366)
DISP:TRAC:Y:MODE REL
to define relative values (see DISPlay[:WINDow<n>]:TRACe<t>:Y[:SCALe]:
TRAC:DATA? TRACE1 to query the trace results (see
and
"Cartesian Diagrams" , on page 376)
3.2.15 Frequency Response Group Delay
The Frequency Response Group Delay of the equalizer is the derivation of phase over frequency. It is a measure of phase distortion.
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Available for source types:
● Equalizer
Remote commands:
LAY:ADD? '1',BEL,EQU
to define the required source type (see LAYout:ADD[:WINDow]?
CALC:FEED 'XFR:DDEM:RAT'
to define the frequency response result type (see CALCulate<n>:FEED on page 365)
CALC:FORM GDEL
to define the group delay result type (see CALCulate<n>:FORMat on page 366)
TRAC:DATA? TRACE1 to query the trace results (see
and
3.2.16 Frequency Response Magnitude
Frequency response of the current equalizer to the input signal. Note that the frequency response of the equalizer is not a pure inverted function of the channel response, as both functions are calculated independantly. The frequency response is calculated by determining an optimal EVM for the input signal.
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Result Types in VSA
Available for source types:
● Equalizer
Remote commands:
LAY:ADD? '1',BEL,EQU
to define the required source type (see LAYout:ADD[:WINDow]?
CALC:FEED 'XFR:DDEM:RAT'
to define the frequency response result type (see CALCulate<n>:FEED on page 365)
CALC:FORM MAGN to define the magnitude result type (see
CALCulate<n>:FORMat on page 366)
TRAC:DATA? TRACE1 to query the trace results (see
and
3.2.17 Frequency Response Phase
The frequency response phase of the equalizer is derived from the Frequency
Response Magnitude.
Available for source types:
● Equalizer
Remote commands:
LAY:ADD? '1',BEL,EQU
to define the required source type (see LAYout:ADD[:WINDow]?
CALC:FEED 'XFR:DDEM:RAT'
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to define the frequency response result type (see CALCulate<n>:FEED on page 365)
CALC:FORM UPH to define the unwrapped phase result type (see
CALCulate<n>:FORMat on page 366)
TRAC:DATA? TRACE1 to query the trace results (see
and
3.2.18 Impulse Response Magnitude
The impulse response magnitude of the equalizer shows the filter in the time domain.
Available for source types:
● Equalizer
Remote commands:
LAY:ADD? '1',BEL,EQU
to define the required source type (see LAYout:ADD[:WINDow]?
CALC:FEED 'XTIM:DDEM:IMP'
to define the impulse response result type (see CALCulate<n>:FEED on page 365)
CALC:FORM MAGN to define the magnitude result type (see
CALCulate<n>:FORMat on page 366)
TRAC:DATA? TRACE1 to query the trace results (see
and
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3.2.19 Impulse Response Phase
The Impulse Response Phase is the derivation of the Impulse Response Magnitude.
Available for source types:
● Equalizer
Remote commands:
LAY:ADD? '1',BEL,EQU
to define the required source type (see LAYout:ADD[:WINDow]?
CALC:FEED 'XTIM:DDEM:IMP'
to define the impulse response result type (see CALCulate<n>:FEED on page 365)
CALC:FORM UPH to define the phase result type (see
CALCulate<n>:FORMat on page 366)
TRAC:DATA? TRACE1 to query the trace results (see
and
3.2.20 Impulse Response Real/Imag
The Real/Imag diagram of the impulse response is a stem diagram. It displays the filter characteristics in the time domain for both the I and the Q branches individually. Using this information the equalizer is uniquely characterized and can be recreated by other applications.
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Result Types in VSA
Available for source types:
● Equalizer
Remote commands:
LAY:ADD? '1',BEL,EQU
to define the required source type (see LAYout:ADD[:WINDow]?
CALC:FEED 'XTIM:DDEM:IMP'
to define the impulse response result type (see CALCulate<n>:FEED on page 365)
CALC:FORM RIM to define the real/image result type (see
CALCulate<n>:FORMat on page 366)
TRAC:DATA? TRACE1 to query the trace results (see
and
3.2.21 Magnitude Absolute
Magnitude of the source signal in an individual capture buffer range (max. 256,000 samples).
If more than 256,000 samples are captured, overlapping result ranges with a size of
256,000 samples each are created. Only one range at a time can be displayed in the
Magnitude Absolute result display.
To scroll through the samples in different ranges, use the "Sweep > Select Result Rng" function or - directly after a sweep - turn the rotary knob. When you scroll in the diagram, the right edge of the current range or the selected result range is displayed in the center of the next range, if possible.
To display the entire capture buffer with all ranges in one diagram, use the Magnitude
result display.
Note that trace modes that calculate results for several sweeps (Average, MinHold,
MaxHold) are applied to the individual ranges and thus may not provide useful results in this result display.
For more information on result ranges see
chapter 4.8, "Capture Buffer Display" , on page 122.
In the Magnitude Absolute result display, the actual signal amplitude is displayed:
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Result Types in VSA
Mag
MEAS
MEAS with t=n ·T
D
and
T
D
=the duration of one sampling period at the defined sample rate defined by the dis-
play points per symbol parameter (see "Display Points/Sym" on page 203)
Available for source types:
● Capture Buffer
● Meas & Ref Signal
(Displays the actual signal amplitude for the selected evaluation range)
Fig. 3-12: Result display "Magnitude Absolute" for capture buffer data
Remote commands:
LAY:ADD? '1',BEL,CBUF
to define the required source type (see LAYout:ADD[:WINDow]?
CALC:FORM MAGN to define the result type (see
CALCulate<n>:FORMat on page 366)
TRAC:DATA? TRACE1 to query the trace results (see
and
"Capture Buffer Results" , on page 375)
3.2.22 Magnitude Overview Absolute
Magnitude of the source signal in the entire capture buffer; the actual signal amplitude is displayed:
Mag
MEAS
MEAS with t=n ·T
D
and
T
D
=the duration of one sampling period at the sample rate defined by the display points per symbol parameter (see
"Display Points/Sym" on page 203)
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Result Types in VSA
Note that for very large numbers of samples (>25,000), the samples are mapped to
25,000 trace points using an autopeak detector for display. Thus, this result display is not suitable to detect transient effects or analyze individual symbols closely. For these purposes, use the
result display instead.
The Magnitude Overview Absolute is only available for the source type:
● Capture Buffer
Fig. 3-13: Result display "Magnitude Overview Absolute" for capture buffer data
Restrictions
Note the following restrictions that apply to this result display:
● Only one trace is available
● Only the trace modes "Clear/Write" and "View" are available.
See also chapter 6.1, "Trace Settings" , on page 190.
Remote commands:
LAY:ADD? '1',BEL,CBUF
to define the required source type (see LAYout:ADD[:WINDow]?
CALC:FORM MOV to define the result type (see
CALCulate<n>:FORMat on page 366)
TRAC:DATA? TRACE1 to query the trace results (see
and
"Capture Buffer Results" , on page 375)
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3.2.23 Magnitude Relative
Magnitude of the source signal; the signal amplitude is scaled to the ideal reference signal
Available for source types:
● Meas & Ref Signal
Fig. 3-14: Result display "Magnitude Relative"
Remote commands:
LAY:ADD? '1',BEL,MEAS
to define the required source type (see LAYout:ADD[:WINDow]?
CALC:FORM MAGN to define the result type (see
CALCulate<n>:FORMat on page 366)
DISP:TRAC:Y:MODE REL
to define relative values (see DISPlay[:WINDow<n>]:TRACe<t>:Y[:SCALe]:
TRAC:DATA? TRACE1 to query the trace results (see
and
"Cartesian Diagrams" , on page 376)
3.2.24 Magnitude Error
Displays the magnitude error of the measurement signal with respect to the reference signal (as a function of symbols over time)
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MAG _ ERR MAG
MEAS
MAG
REF with t=n ·T
D
and T
D
=the duration of one sampling period at the sample rate defined by the display points per symbol parameter (see
"Display Points/Sym" on page 203).
Fig. 3-15: Result display "Magnitude Error"
Available for source types:
● Modulation Errors
Remote commands:
LAY:ADD? '1',BEL,MERR
to define the required source type (see LAYout:ADD[:WINDow]?
CALC:FORM MAGN to define the result type (see
CALCulate<n>:FORMat on page 366)
TRAC:DATA? TRACE1 to query the trace results (see
and
"Cartesian Diagrams" , on page 376)
3.2.25 Phase Error
Displays the phase error of the measuremente signal with respect to the reference signal as a function of symbols over time.
PHASE _ ERR
PHASE
MEAS
PHASE
REF with t=n ·T
D
and T
D
=the duration of one sampling period at the sample rate defined by the display points per symbol parameter (see
"Display Points/Sym" on page 203).
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Fig. 3-16: Result display "Phase Error"
Available for source types:
● Modulation Errors
Remote commands:
LAY:ADD? '1',BEL,MERR
to define the required source type (see LAYout:ADD[:WINDow]?
CALC:FORM PHAS to define the result type (see
CALCulate<n>:FORMat on page 366)
TRAC:DATA? TRACE1 to query the trace results (see
and
"Cartesian Diagrams" , on page 376)
3.2.26 Phase Wrap
The phase or argument of the signal; the display is limited to the phase value range of
[-180°, 180°]
Phase
MEAS
MEAS
with t=n ·T
D
and T
D
=the duration of one sampling period at the sample rate defined by the display points per symbol parameter (see
"Display Points/Sym" on page 203).
Available for source types:
● Meas & Ref Signal
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Fig. 3-17: Result display "Phase Wrap"
Remote commands:
LAY:ADD? '1',BEL,REF
to define the required source type (see LAYout:ADD[:WINDow]?
CALC:FORM PHASe to define the result type (see
CALCulate<n>:FORMat on page 366)
TRAC:DATA? TRACE1 to query the trace results (see
and
"Cartesian Diagrams" , on page 376)
3.2.27 Phase Unwrap
The phase of the signal; the display is not limited to [-180°, 180°].
Available for source types:
● Meas & Ref Signal
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Fig. 3-18: Result display "Phase Unwrap"
Remote commands:
LAY:ADD? '1',BEL,MEAS
to define the required source type (see LAYout:ADD[:WINDow]?
CALC:FORM UPHase to define the result type (see
CALCulate<n>:FORMat on page 366)
TRAC:DATA? TRACE1 to query the trace results (see
and
"Cartesian Diagrams" , on page 376)
3.2.28 Real/Imag (I/Q)
Real and imaginary part of the measurement or reference signal in separate measurement diagrams; the x-axis (scaled in time units or symbols) is identical for both diagrams.
Available for source types:
● Capture Buffer
● Meas & Ref Signal
● Error Vector
Capture buffer display
Note that this result display is based on an individual capture buffer range. If more than
256,000 samples are captured, overlapping ranges with a size of 256,000 each are created. Only one range at a time can be displayed in the Real/Imag result display. For details see
chapter 4.8, "Capture Buffer Display" , on page 122.
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Result Types in VSA
The scaling of the capture buffer depends on the input source:
● Scaling is relative to the current reference level for RF input.
● Scaling is relative to the full scale level for I/Q input.
Fig. 3-19: Result display "Real/Imag (I/Q)"
Remote commands:
LAY:ADD? '1',BEL,MEAS
to define the required source type (see LAYout:ADD[:WINDow]?
CALC:FORM RIMag to define the result type (see
CALCulate<n>:FORMat on page 366)
TRAC:DATA? TRACE1 to query the trace results (see
and
"Cartesian Diagrams" , on page 376)
3.2.29 Result Summary
The Modulation Accuracy results in a table. For details on the parameters see
chapter 3.3, "Common Parameters in VSA" , on page 54.
Basis of evaluation
The majority of the values that are displayed in the Result Summary are calculated
parameter. For example, if "Display Points/Symbol" is "1", only the symbol instants contribute to the result displayed in the result summary.
Table 3-2: Results calculated over the evaluation range
PSK, MSK, QAM FSK
EVM Frequency Error
MER
Phase Error
Magnitude Error
Power
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Result Types in VSA
PSK, MSK, QAM
Magnitude Error
Rho
Power
FSK
The following results that are based on internal estimation algorithms (see
"Signal Model, Estimation and Modulation Errors" , on page 100) are calculated over
the "Estimation range" (see also
chapter 4.5.1.2, "Estimation" , on page 101).
Table 3-3: Results calculated over the estimation range
PSK, MSK, QAM FSK
Carrier Frequency Error
Symbol Rate Error
I/Q Offset
I/Q Imbalance
Gain Imbalance
Quadrature Error
Amplitude Droop
FSK Deviation Error
Symbol Rate Error
FSK Measurement Deviation
Carrier Frequency Error
Carrier Frequency Drift
Current value
In the "Current" column, the value evaluation for the current evaluation is displayed.
For example, the EVM Peak value in the current sweep corresponds to the peak of the trace values within the evaluation range for the current sweep (as indicated by marker
).
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Fig. 3-20: Example for result summary with current EVM peak value marked
If you want to compare the trace values to the results of the Result Summary, make sure to match the displayed points per symbol of the trace and of the Result Summary.
Refer to
"Display Points/Sym" on page 203 for details.
Mean value
In the "Mean" column, the linear mean of the values that are in the "Current" column is displayed. Note that if the values are in a logarithmic representation, e.g. the I/Q Offset, the linear values are averaged.
Peak value
In the "Peak" column, the maximum value that occurred during several evaluations is displayed. Note that when the value can be positive and negative, e.g. the phase error, the maximum absolute value (maintaining its sign) is displayed. The peak value of Rho is handled differently, since its minimum value represents the worst case. In that case, the minimum value is displayed.
Standard Deviation
The value for the standard deviation is calculated on the linear values and then converted to the displayed unit.
95-percentile
The 95-percentile value is based on the distribution of the current values. Since the phase error and the magnitude error can usually be assumed to be distributed around zero, the 95-Percentile for these values is calculated based on their absolute values.
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Result Types in VSA
Again, the Rho value is handled differently. Here, the 5-Percentile is displayed, since the lowest Rho value represents the worst case.
Remote commands:
LAY:ADD? '1',BEL, MACC
to define the required source type (see LAYout:ADD[:WINDow]?
CALC:FORM RSUM to define the result type (see
CALCulate<n>:FORMat on page 366)
TRAC:DATA? TRACE1 to query the trace results (see
TRACe<n>[:DATA] on page 374 and
"Result Summary" , on page 376)
CALC:MARK:FUNC:DDEM:STAT:<parameter> to query individual parameter values (see
chapter 11.9.3, "Retrieving Parameter Values" , on page 377
Result Summary - Individual Results
The Result Summary can display either all or only a single modulation accuracy parameter. Only the most important parameters can be displayed individually, namely
those for which modulation accuracy limits can be defined (see "Limit Value" on page 200).
Individual results are selected for display by clicking in the Result Summary table header. A "Table Configuration" dialog box is displayed in which you can select the parameter to be displayed.
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By default, all parameters are displayed. If you select a specific parameter, the Result
Summary display is replaced by the individual result display.
Fig. 3-21: Result display for individual value in Result Summary
In addition to the current measurement value, the statistical results (see
chapter 3.2.29, "Result Summary" , on page 47) and the peak limit value (see
"Limit Value" on page 200) for the selected parameter are displayed.
For details on the displayed results see chapter 3.3, "Common Parameters in VSA" , on page 54.
Remote command:
DISPlay[:WINDow<n>]:ITEM[:LINE][:VALue] on page 368
3.2.30 Symbol Table
Symbol numbers are displayed as a table. Each symbol is represented by an entry in the table. The symbols can be displayed in binary, octal, hexadecimal or decimal format. Selected symbols (using markers) are highlighted by a blue frame.
Example:
Fig. 3-22: Result display for "Symbols" in hexadecimal mode
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If a pattern search is active, a found pattern is indicated by a green background in the symbol table. If, during demodulation, individual symbols do not match the pattern after all, these symbols are indicated by a red frame.
Remote commands:
LAY:ADD? '1',BEL, 'XTIM:DDEM:SYMB'
to define the required source type (see LAYout:ADD[:WINDow]?
TRAC:DATA? TRACE1 to query the trace results (see
and
3.2.31 Vector Frequency
The instantenous frequency of the source signal as an X/Y plot; all available samples
(as defined by the display points per symbol parameter (see
"Display Points/Sym" on page 203)) are drawn and connected.
Available for source types:
● Meas & Ref Signal
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Fig. 3-23: Result display for "Vector Frequency"
Remote commands:
LAY:ADD? '1',BEL,MEAS
to define the required source type (see LAYout:ADD[:WINDow]?
CALC:FORM COVF to define the result type (see
CALCulate<n>:FORMat on page 366)
TRAC:DATA? TRACE1 to query the trace results (see
and
"Polar Diagrams" , on page 376)
3.2.32 Vector I/Q
The complex source signal as an X/Y plot; all available samples (as defined by the display points per symbol parameter, see
"Display Points/Sym" on page 203) are drawn
and connected.
The scaling of the capture buffer depends on the input source:
● Scaling is relative to the current reference level for RF input.
● Scaling is relative to the full scale level for I/Q input.
Available for source types:
● Capture Buffer
● Meas & Ref Signal
● Error Vector
Capture buffer display
Note that this result display is based on an individual capture buffer range. If more than
256,000 samples are captured, overlapping ranges with a size of 256,000 each are created. Only one range at a time can be displayed in the Vector I/Q result display. For details see
chapter 4.8, "Capture Buffer Display" , on page 122.
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Fig. 3-24: Result display for "Vector I/Q"
Remote commands:
LAY:ADD? '1',BEL,MEAS
to define the required source type (see LAYout:ADD[:WINDow]?
CALC:FORM COMP to define the result type (see
CALCulate<n>:FORMat on page 366)
TRAC:DATA? TRACE1 to query the trace results (see
and
"Polar Diagrams" , on page 376)
3.3 Common Parameters in VSA
Depending on the modulation type you are using, different signal parameters are determined during vector signal analysis.
Details concerning the calculation of individual parameters can be found in
"Signal Model, Estimation and Modulation Errors" , on page 100 and
chapter A.6, "Formulae" , on page 425.
Table 3-4: Parameters for PSK, QAM and MSK modulation
Parameter Description SCPI Parameter
EVM - RMS/Peak EVM
MER - RMS/Peak
Phase Error - RMS/
Peak
Error Vector Magnitude, normalized to mean reference power by default (see
"Normalize EVM to" on page 181)
Modulation Error Ratio
The phase difference between the measurement vector and the reference vector
SNR
PERR
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Parameter
Magnitude Error -
RMS/Peak
Carrier Frequency
Error
Symbol Rate Error
Description SCPI Parameter
The average (RMS) and peak magnitude error in %. The magnitude error is the difference of the measured magnitude to the magnitude of the reference signal. The magnitude error is normalized to the mean magnitude of the reference signal.
MERRor
The mean carrier frequency offset in Hz CFERror
Rho
I/Q Offset
I/Q Imbalance
Gain Imbalance
Quadrature Error
Amplitude Droop
Power
Difference between the currently measured symbol rate and the defined symbol rate in ppm.
(Only for PSK, QAM or UserQAM modulation and only if
compensation for SRE is activated, see chapter 5.9.1,
"Demodulation - Compensation" , on page 176)
Offset in the original input
Not for BPSK.
Not for BPSK.
Not for BPSK.
SRER
RHO
OOFFset
IQIMbalance
GIMBalance
QERRor
The decrease of the signal power over time in the transmitter ADRoop
The power of the measured signal MPOWer
Table 3-5: Parameters for FSK modulation only
Parameter Description
Frequency Error - RMS/
Peak
The average (RMS) and peak frequency error in %. The frequency error is thedifference of the measured frequency and the reference frequency.The frequency error is normalized to the estimated FSK deviation.
SCPI parameter
FSK:DERRor
FSK Deviation Error The deviation error of FSK modulated signals in Hz. The
FSK deviation erroris the difference of the FSK deviation of the measured signal and the FSK referencedeviation you have set.
FDERror
The estimated deviation of FSK modulated signals in Hz.
FSK:MDEViation FSK Meas Deviation
FSK Ref Deviation The reference deviation you have set in Hz.
Carrier Frequency Drift The mean carrier frequency drift in Hz per symbol.
FSK:RDEViation
FSK:CFDRift
Remote command:
CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:<Parameter>?
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4 Measurement Basics
Some background knowledge on basic terms and principles used in VSA is provided here for a better understanding of the required configuration settings.
For information on the basic processing of I/Q data in the R&S FPS see the R&S FPS
I/Q Analyzer User Manual.
● Known Data Files - Dependencies and Restrictions .............................................123
4.1 Filters and Bandwidths During Signal Processing
This section describes the used filters in vector signal analysis with an R&S FPS, as well as the bandwidth after each filter.
The relevant filters for vector signal analysis are shown in figure 4-1 .
Fig. 4-1: Block diagram of bandwidth-relevant filters for vector signal analysis
● After the IF Filter (only for RF input operation): bandwidth = 40 MHz
● After the digital hardware section:
The phase and amplitude distortions of the IF filter have been compensated for.
Usually, the I/Q data has a usable bandwidth of about:
0.8 * sample rate
For details refer to chapter 4.1.1, "I/Q Bandwidth" , on page 57.
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The I/Q data's sample rate and bandwidth are automatically adjusted to the set symbol rate. For most modulated signals even the smallest allowed value for the sample rate leads to a sufficient I/Q data bandwidth. The whole spectrum of the input signal is captured, but most adjacent channels and interferers are effectively suppressed. Only for very wide signals (FSK, no TX-filter used) it can be necessary
to try higher values for the sample rate (see chapter 4.2, "Sample Rate, Symbol
Rate and I/Q Bandwidth" , on page 63), increasing the I/Q bandwidth. The I/Q
data delivered to the DSP section has no considerable amplitude or phase distortion and a suitable bandwidth.
The "Signal Capture" dialog box ("Data Acquisition" tab) shows the sample rate and
the usable I/Q bandwidth achieved for the current settings (see "Usable I/Q Bandwidth" on page 156).
● After the optional measurement filter:
The measurement signal and the reference signal can be filtered by various measurement filters which have different bandwidths.
The filters described above are the ones that directly affect the bandwidth of the captured I/Q data and the final measurement signal and reference signal. Note, however, that several other filters are also involved in the DSP section but are not mentioned above:
● Receive filter to prevent ISI (intersymbol-interference)
● filters necessary for various estimators
● others
4.1.1 I/Q Bandwidth
The bandwidth of the I/Q data used as input for the vector signal analysis is filtered as
depends on:
● the used sample rate, which depends on:
– the defined "Symbol Rate" (see
– the defined "Sample Rate" parameter (see
For details on the maximum usable bandwidth see
chapter 4.2, "Sample Rate, Symbol
Rate and I/Q Bandwidth" , on page 63.
The sample rate and the usable I/Q bandwidth achieved for the current settings is dis-
played in the "Signal Capture" dialog, see chapter 5.6.1, "Data Acquisition" , on page 155.
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4.1.2 Demodulation Bandwidth (Measurement Bandwidth)
Some modulation systems do not use a receive filter. In these cases special care should be taken that no interference or adjacent channels occur within the demodula-
Typical communication systems demand special receive or measurement filters (e.g.
root-raised cosine receive filter or EDGE measurement filter).
If no such filtering is performed, care should be taken that neither interfering signals nor adjacent channels fall within the demodulation bandwidth.
4.1.3 Modulation and Demodulation Filters
Sample points are required for demodulation in the analyzer, where only information of the current symbol and none of neighbouring symbols is present (symbol points).
These points are also called ISI-free points (ISI = intersymbol interference). If the transmitter does not provide an ISI-free signal after the transmit filter (TX filter), this condition can be fulfilled by signal-specific filtering of the analyzer input signal (receive filter or Rx filter). If an RRC (root-raised cosine) filter is used in the transmitter, an RRC filter is also required in the analyzer to obtain ISI-free points.
In many PSK systems, RRC filters are used as transmit, ISI and measurement filters.
To determine the I/Q modulation error, the measurement signal must be compared with the corresponding ideal signal. For this purpose a reference filter is required which is calculated by the analyzer by convolving the coefficient of the transmit filter
(Tx filter) and the meas filter (see figure 4-2 ).
If unfiltered signals have to be measured as well (e.g. to determine nonlinear signal distortions), no measurement filter is switched into the signal path and the reference
filter is identical to the Transmit filter (see figure 4-2 ).
In the baseband block diagrams (see figure 4-2 ), the system-theoretical transmitter and
analyzer filters are shown for PSK and QAM demodulation. For the sake of clearness,
RF stages, IF filters and the filter stages of the digital hardware section are not shown.
For a correct demodulation, the following filters have to be accurately specified for the analyzer:
● Transmit filter: filter characteristic of transmitter
● Meas filter:
– PSK, QAM, UserQAM, MSK:
The I and the Q part of the measurement and the reference signal are filtered with this filter.
– FSK:
The instantaneous frequency of the measurement reference signal are filtered.
In many applications, the measurement filter is identical with the ISI filter.
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The receive filter (ISI filter) is configured internally depending on the transmit filter. The goal is to produce intersymbol-interference-free points for the demodulation.
The reference filter synthesizes the ideal transmitted signal (after meas filtering). It is calculated by the analyzer from the above filters (convolution operation Transmit filter
* Meas Filter).
Typical combinations of Tx and Meas filters are shown in table 1-4
; they can be set in
the VSA application using "Meas filter = AUTO" (see "Using the Transmit Filter as a
Measurement Filter (Auto)" on page 186). If RC (raised cosine), RRC (root-raised
cosine) and Gaussian filters are used, the Alpha (RC, RRC filters) or BT (Gaussian filters) parameters must be set in addition to the filter characteristic (roll-off factor). Typically the Alpha/BT value of the measurement filter should be the same as that of the transmission filter.
4.1.4 Measurement Filters
The measurement filter can be used to filter the following two signals in the same way:
● the measurement signal (after coarse frequency, phase and timing synchronization have been achieved)
● the reference signal, i.e the I/Q symbols that have been determined in the demodulator and have already been filtered with the Transmit filter;
For FSK, the measurement filter filters the instantaneous frequency of the signal, not the I/Q signal.
For MSK, PSK, QAM and User QAM the measurement filter filters the real part and imaginary part of these signals (i.e. not the instantaneous frequency or magnitude of the signal).
The VSA application defines the error signal as the difference between the reference signal and the measurement signal. Thus, the measurement filter also shapes the spectrum of the error signal, which is used to calculate the EVM, for example.
In many applications the measurement filter is the same as the RX filter. However, unlike the measurement filter, the RX filter is not relevant for the measurement, but is only required to create the reference signal optimally.
The RX filter and the transmit filter are usually chosen such that their combination
results in an Inter-Symbol Interference (ISI) free system (see figure 4-2
and
).
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Fig. 4-2: Measurement filter in the block diagram (MSK, PSK, QAM and UserQAM)
Fig. 4-3: Modulator with Transmit filter in detail
As the measurement filters of the VSA application have low-pass characteristics, they suppress high frequency distortion components in the Meas/Ref/Error signal. The errors are weighted spectrally. Thus, turning off the measurement filter can have an influence on the numeric and graphical error values. However, the measurement filter should be switched off if non-linear distortions have to be measured (they usually produce high frequency components).
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Predefined measurement filters
The most frequently required measurement filters are provided by the VSA application
(see chapter A.3.2, "Measurement Filters" , on page 420).
The frequency response of the available standard-specific measurement filters is
shown in chapter A.6.6.2, "Measurement Filter" , on page 433.
4.1.5 Customized Filters
The analytical filter types RC (raised cosine), RRC (root-raised cosine) and GAUS-
SIAN as well as the most important standard-specific filters are already integrated in the VSA application. In addition, it is possible to use user-defined measurement and transmit filters. Customized filters may be useful for the following purposes:
● Development of new networks and modulation methods for which no filters are defined yet.
● Measurements of transmitter characteristics with slightly modified (e.g. shortened) transmitter filters.
An external program ("FILTWIZ") is offered to convert user-defined filters. This program generates filter files (*.vaf) which can be transferred to the analyzer with a USB device, for example. The program can be downloaded together with a detailed description as a precompiled MATLAB® file (MATLAB pcode) on the Internet, at http:// www.rohde-schwarz.com
(search term "FILTWIZ").
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Fig. 4-4: FILTWIZ - filter tool for VSA
It is possible to load customized transmit filters and customized measurement filters. If a customized transmit filter is selected, the internal receive filter coefficients are calculated automatically on the fly.
Note that this is different to the R&S FSQ-K70, where it is necessary to also transfer a user receive filter.
If you upload a customized transmit filter and leave the measurement filter set to "automatic", the internally calculated receive filter will be used as measurement filter. Note that this filter is not necessarily suitable for your specific signal. The filter is optimized such that the intersymbol interference is low. Hence, you will probably be able to see a clear eye diagram and an Vector I/Q diagram with a recognizable constellation. However, a filter that has low intersymbol interference might lead to noise enhancement, which is commonly undesirable for a measurement filter. In order to avoid noise enhancement, it is recommended that you:
● a) design your own measurement filter and upload it as a user filter
● b) select a suitable measurement filter from the list
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Sample Rate, Symbol Rate and I/Q Bandwidth
Transferring filter files to the R&S FPS
You can transfer the (.vaf) filter files to the R&S FPS using a USB memory device.
4.2 Sample Rate, Symbol Rate and I/Q Bandwidth
The "Symbol Rate" defined in the "Signal Description" settings determines how many symbols are captured and demodulated during a certain measurement time. However, for each symbol more than one sample may be captured, so that the sample rate may be higher than the symbol rate.
The "Sample Rate" parameter in the "Data Acquisition" settings defines the number of
samples to capture per symbol (not to be confused with the estimation points per
symbol or display points per symbol, see chapter 4.7, "Display Points vs Estimation
Points per Symbol" , on page 121). The resulting sample rate (depending on the "Sym-
bol Rate") is indicated behind the parameter.
The number of samples to capture per symbol was referred to as the "Capture Over-
sampling" value in previous R&S signal and spectrum analyzers.
The resulting sample rate, also referred to as the user or output sample rate, is the rate at which the I/Q data is demodulated and analyzed. The sample rate also affects the demodulation (measurement) bandwidth. If the bandwidth is too narrow, the signal is not displayed completely. If the bandwidth is too wide, interference from outside the actual signal to be measured can distort the result. Thus, for signals with a large frequency spectrum (e.g. FSK modulated signals), a higher sample rate may be necessary.
For an indication of the required sample rate, view the "Real/Imag (I/Q)" display of the capture buffer with a "Spectrum" transformation. If the complete signal is displayed within the usable I/Q bandwidth, the selected value is suitable.
Fig. 4-5: Determining the I/Q bandwidth: Real/Imag (I/Q) display of the capture buffer with a spectrum transformation
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If the signal is cut off, increase the sample rate; if it is too small, decrease the sample rate (by changing the "Symbol Rate" defined in the "Signal Description" settings, or the
"Sample Rate" parameter in the "Data Acquisition" settings).
As described above, the sample rate is determined by the number of samples to capture per symbol. Thus, the maximum sample rate depends on the maximum number of symbols to be captured (the symbol rate) and vice versa. The maximum sample rate for the R&S FPS is 10 GHz (see below). Thus, the maximum symbol rate is:
Table 4-1: Maximum symbol rate depending on sample rate parameter
Sample rate parameter Max. symbol rate
4* symbol rate
8* symbol rate
16* symbol rate
32* symbol rate
2500 MSymbols
1250 MSymbols
625 MSymbols
312.5 MSymbols
4.2.1 Sample Rate and Maximum Usable I/Q Bandwidth for RF Input
Definitions
● Input sample rate (ISR): the sample rate of the useful data provided by the device connected to the input of the R&S FPS
● (User, Output) Sample rate (SR): the sample rate that is defined by the user (e.g.
in the "Data Aquisition" dialog box in the "I/Q Analyzer" application) and which is used as the basis for analysis or output
● Usable I/Q (Analysis) bandwidth: the bandwidth range in which the signal remains undistorted in regard to amplitude characteristic and group delay; this range can be used for accurate analysis by the R&S FPS
● Record length: Number of I/Q samples to capture during the specified measurement time; calculated as the measurement time multiplied by the sample rate
For the I/Q data acquisition, digital decimation filters are used internally in the
R&S FPS. The passband of these digital filters determines the maximum usable I/Q
bandwidth. In consequence, signals within the usable I/Q bandwidth (passband) remain unchanged, while signals outside the usable I/Q bandwidth (passband) are suppressed. Usually, the suppressed signals are noise, artifacts, and the second IF side band. If frequencies of interest to you are also suppressed, you should try to increase the output sample rate, since this increases the maximum usable I/Q bandwidth.
Bandwidth extension options
The maximum usable I/Q bandwidth provided by the R&S FPS in the basic installation can be extended by additional options. These options can either be included in the initial installation (B-options) or updated later (U-options). The maximum bandwidth provided by the individual option is indicated by its number, for example, B40 extends the bandwidth to 40 MHz.
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As a rule, the usable I/Q bandwidth is proportional to the output sample rate. Yet, when the I/Q bandwidth reaches the bandwidth of the analog IF filter (at very high output sample rates), the curve breaks.
● Relationship Between Sample Rate and Usable I/Q Bandwidth .............................65
● Relationship Between Sample Rate, Record Length and Usable I/Q Bandwidth ... 65
● R&S FPS without additional bandwidth extension options ..................................... 66
● R&S FPS with option B40 (I/Q Bandwidth Extension): ........................................... 67
● R&S FPS with activated option B160 (I/Q Bandwidth Extension): ..........................67
4.2.1.1
Bandwidth Extension Options
Max. usable I/Q BW
40 MHz
160 MHz
Required B-option
B40
B160
4.2.1.2
Relationship Between Sample Rate and Usable I/Q Bandwidth
Up to the maximum bandwidth, the following rule applies:
Usable I/Q bandwidth = 0.8 * Output sample rate
MSRA operating mode
In MSRA operating mode, the MSRA Master is restricted to a sample rate of 600 MHz.
shows the maximum usable I/Q bandwidths depending on the output sample rates.
4.2.1.3
Relationship Between Sample Rate, Record Length and Usable I/Q Bandwidth
Up to the maximum bandwidth, the following rule applies:
Usable I/Q bandwidth = 0.8 * Output sample rate
Regarding the record length, the following rule applies:
Record length = Measurement time * sample rate
Maximum record length for RF input
The maximum record length, that is, the maximum number of samples that can be captured, depends on the sample rate.
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Table 4-2: Maximum record length
Sample rate Maximum record length
100 Hz to 200 MHz
200 MHz to 10 GHz
(upsampling)
440 MSamples (precisely: 461373440 (= 440*1024*1024) samples)
220 MSamples
shows the maximum usable I/Q bandwidths depending on the output sample rates.
Fig. 4-6: Relationship between maximum usable I/Q bandwidth and output sample rate with and without bandwidth extensions
4.2.1.4
R&S FPS without additional bandwidth extension options sample rate: 100 Hz - 10 GHz maximum bandwidth: 28 MHz
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Symbol Mapping
Sample rate
100 Hz to 35 MHz
35 MHz to 10 GHz
Maximum I/Q bandwidth proportional up to maximum 28 MHz
28 MHz
4.2.1.5
R&S FPS with option B40 (I/Q Bandwidth Extension): sample rate: 100 Hz - 10 GHz maximum bandwidth: 40 MHz
Sample rate
100 Hz to 50 MHz
50 MHz to 10 GHz
Maximum I/Q bandwidth proportional up to maximum 40 MHz
40 MHz
4.2.1.6
R&S FPS with activated option B160 (I/Q Bandwidth Extension): sample rate: 100 Hz - 10 GHz maximum bandwidth: 160 MHz
Sample rate
100 Hz to 200 MHz
200 MHz to 10 GHz
Maximum I/Q bandwidth proportional up to maximum 160 MHz
160 MHz
Restrictions
The optional bandwidth extension R&S FPS-B160 can not be activated if any of the following conditions apply:
● R&S FPS firmware versions previous to 1.20
● For center frequencies larger than 7 GHz
● With any trigger except for an external trigger
4.3 Symbol Mapping
Mapping or symbol mapping means that symbol numbers are assigned to constellation points or transitions in the I/Q plane (e.g. PSK and QAM).
In the analyzer, the mapping is required to decode the transmitted symbols from the sampled I/Q or frequency/time data records.
The mappings for all standards used in the analyzer and for all employed modulation modes are described in the following. Unless indicated otherwise, symbol numbers are specified in hexadecimal form (MSB at the left).
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4.3.1 Phase Shift Keying (PSK)
With this type of modulation, the information is represented by the absolute phase position of the received signal at the decision points. All transitions in the I/Q diagram are possible. The complex constellation diagram is shown. The symbol numbers are entered in the diagram according to the mapping rule.
BPSK (NATURAL)
1 0
Fig. 4-7: Constellation diagram for BPSK including the symbol mapping
QPSK
2 0
3 1
Fig. 4-8: Constellation diagram for QPSK including the symbol mapping for CDMA2000 FWD and DVB
S2
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1
3 0
2
Fig. 4-9: Constellation diagram for QPSK (GRAY) including the symbol mapping
1 0
2 3
Fig. 4-10: Constellation diagram for QPSK (NATURAL) including the symbol mapping
1
3 0
2
Fig. 4-11: Constellation diagram for QPSK including the symbol mapping for WCDMA
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8PSK
2
3
1
6 0
7 4
5
Fig. 4-12: Constellation diagram for 8PSK (GRAY) including the symbol mapping
2
3 1
4
2
0
5 7
6
Fig. 4-13: Constellation diagram for 8PSK (NATURAL) including the symbol mapping
4
6 0
1
3 5
7
Fig. 4-14: Constellation diagram for 8PSK including the symbol mapping for DVB S2
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4.3.2 Rotating PSK
A rotating PSK modulation is basically a PSK modulation in which additional phase shifts occur. These phase shifts depend on the symbol number, e.g. for a π/4-QPSK, the third symbol has an additional phase offset of (3-1)* π/4. This offset has the same effect as a rotation of the basic system of coordinates by the offset angle after each symbol.
The method is highly important in practical applications because it prevents signal transitions through the zeros in the I/Q plane. This reduces the dynamic range of the modulated signal and the linearity requirements for the amplifier.
In practice, the method is used for 3 π/8-8PSK, for example, and (in conjunction with phase-differential coding) for π/4-DQPSK.
Symbol mapping
The logical constellation diagram for 3 π/8-8PSK comprises 8 points that correspond to
the modulation level (see figure 4-15 ). A counter-clockwise offset (rotation) of 3
π/8 is inserted after each symbol transition.
2
0 3
1 7
5 6
4
Fig. 4-15: Constellation diagram for 3 π/8 8PSK before rotation including the symbol mapping for
EDGE
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Fig. 4-16: I/Q symbol stream after 3 π/8 rotation in I/Q plane if the symbol number "7" is transmitted six times in a row
2 0
3 1
Fig. 4-17: Constellation diagram for 3 π/4 QPSK including the symbol mapping for EDGE
1
2 0
3
Fig. 4-18: Constellation diagram for π/4 QPSK (Natural) including the symbol mapping
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4.3.3 Differential PSK
With differential PSK, the information is represented in the phase shift between two consecutive decision points. The absolute position of the complex sample value at the decision point does not carry information.
In the physical constellation diagram, the constellation points at the symbol decision points obtained after ISI-free demodulation are shown (as with common PSK methods). This diagram corresponds to the display on the analyzer. The position of the constellation points is standard-specific. For example, some QPSK standards define the constellation points on the diagonals, while other standards define the coordinate axes.
In
, the symbols are assigned to phase shifts. The QPSK (INMARSAT) mapping corresponds to simple QPSK with phase-differential coding.
Tables table 4-4 and table 4-5
show two types of differential 8PSK modulation.
Differential coding according to VDL is shown in
. It can be used for modulation types with 3 bits/symbol, e.g. 8PSK.
Other types of modulation using differential coding method are described in
chapter 4.3.4, "Rotating Differential PSK Modulation" , on page 74.
Fig. 4-19: Constellation diagram for DQPSK (INMARSAT and NATURAL) including the symbol mapping
Table 4-3: DQPSK (INMARSAT)
Logical symbol mapping
Modulation symbol (binary indication: MSB, LSB)
Phase shift
00
0°
01
-90°
10
+90°
11
180°
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Fig. 4-20: Constellation diagram for D8PSK including the symbol mapping for APCO25, APCO25
Phase 2, GRAY, NATURAL and TETRA
Table 4-4: D8PSK (NATURAL)
Logical symbol mapping
Modulation symbol (binary indication: MSB, LSB)
000
Phase shift 0°
001
45°
010
90°
011
135°
100
180°
101
225°
110
270°
111
315°
Table 4-5: D8PSK (GRAY)
Logical symbol mapping
Modulation symbol (binary indication: MSB, LSB)
000
Phase shift 0°
Table 4-6: D8PSK (VDL)
Logical symbol mapping
Modulation symbol (binary indication: MSB, LSB)
Phase shift
000
0°
001
45°
001
45°
010
135°
010
135°
011
90°
011
90°
100
270°
100
315°
101
315°
101
270°
110
225°
110
180°
111
180°
111
225°
4.3.4 Rotating Differential PSK Modulation
Phase-differential modulation is frequently combined with an additional phase shift
(e.g. π/4 DQPSK = π/4 phase shift modulation + differential modulated 4PSK).
The logical mapping diagram corresponds to the diagram for DPSK.
The physical constellation diagram shows the symbol decision points obtained after
ISI-free demodulation.
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Fig. 4-21: Constellation diagram for π/4 DQPSK including the symbol mapping for APCO25 Phase 2,
NADC, NATURAL, PDC, PHS, TETRA and TFTS; the π/4 rotation is already compensa- ted for
Table 4-7: π/4 DQPSK (NADC, PDC, PHS, TETRA)
Logical symbol mapping
Modulation symbol (binary indication: MSB, LSB)
Phase shift
00
0°+45°
01
90°+45°
10
-90°+45°
11
-180°+45°
Table 4-8: π/4 DQPSK (TFTS)
Logical symbol mapping
Modulation symbol (binary indication: MSB, LSB)
Phase shift
00
-180°+45°
01
90°+45°
10
-90°+45°
11
0°+45°
Table 4-9: π/4 DQPSK (Natural)
Logical symbol mapping
Modulation symbol (binary indication: MSB, LSB)
Phase shift
00
0°+45°
Table 4-10: π/4 DQPSK (APCO25 and APCO25Phase2)
Logical symbol mapping
Modulation symbol (binary indication: MSB, LSB)
Phase shift
00
0°+45°
01
90°+45°
01
90°+45°
10
-180°+45°
10
-90°+45°
11
-90°+45°
11
-180°+45°
4.3.5 Offset QPSK
Offset QPSK differs from "normal" QPSK in the fact that the Q component is delayed by half a symbol period against the I component in the time domain. Hence, the symbol time instants of the I and the Q component do not coincide. The concept of Offset
QPSK is illustrated in the diagrams below.
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Derivation of OQPSK
Table 4-11: I/Q diagram and constellation diagram
QPSK
2
1
0
-1
-2
0 1 2 3 4 5 6 7 8 9
2
1
0
-1
-2
0 1 2 3 4
Time
6 7 8 9
[symbols]
1
0
1
0
PSK vector diagram with alpha = 0.35
2
OQPSK (delayed Q component)
2
1
0
-1
-2
0 1 2 3 4 5 6 7 8 9
2
1
0
-1
-2
0 1 2 3 4
Time
7 8 9
[symbols]
1
0
1
0
OQPSK vector diagram with alpha = 0.35
2
1
0
1
0
-1 -1
-2
-2 -1 0
Inphase
1 2
-2
-2 -1 0
Inphase
1 2
Offset QPSK reduces the dynamic range of the modulated signal (with respect to "normal" QPSK) and, therefore, the demands on amplifier linearity by avoiding zero crossings.
A distinction is made in the analyzer display:
In the Vector I/Q result display of the measurement (or reference) signal, the time delay is not compensated for. The display corresponds to the physical diagram shown in (
In the Constellation I/Q result display of the measurement (or reference) signal, the time delay is compensated for. The display corresponds to the logical mapping as in
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OQPSK
2 0
Measurement Basics
Symbol Mapping
3 1
Fig. 4-22: Constellation diagram for OQSK (GRAY) including the symbol mapping
4.3.6 Frequency Shift Keying (FSK)
To illustrate symbol mappings for FSK modulations, the symbol numbers are marked in the logical mapping diagram versus the instantaneous frequency. An instantaneous frequency of zero in the baseband corresponds to the input frequency of the analyzer.
2FSK (NATURAL)
With 2FSK, the symbol decision is made by a simple frequency discriminator:
Symbol
Numbers
1 1
0 -1
Fig. 4-23: Constellation diagram for 2FSK (NATURAL) including the logical symbol mapping
4FSK
With 4FSK, the symbol decision is made by a frequency discriminator with 3 decision thresholds (-2/3; 0; +2/3) normalized to the FSK reference deviation.
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Symbol
Numbers
3 -1
2 1/3
1 -1/3
0 -1
Fig. 4-24: Constellation diagram for 4FSK (NATURAL) including the logical symbol mapping
2 -1
Symbol
Numbers
3 1/3
1 -1/3
0 -1
Fig. 4-25: Constellation diagram for 4FSK (GRAY) including the logical symbol mapping
1 -1
Symbol
Numbers
0 1/3
2 -1/3
3 -1
Fig. 4-26: Constellation diagram for 4FSK for APCO C4FM and APCO Phase 2 including the logical symbol mapping
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8FSK (NATURAL)
7 1
6 5/7
5 3/7
Symbol
Numbers
4 1/7
3 -1/7
2 -3/7
1 -5/7
0 -1
Fig. 4-27: Constellation diagram for 8FSK (NATURAL) including the logical symbol mapping
4.3.7 Minimum Shift Keying (MSK)
MSK modulation causes modulation-dependent phase shifts of +/- 90° which can be shown in an Constellation I/Q diagram. As with PSK, demodulation is performed by evaluation of the phase positions.
Table 4-12: MSK (NATURAL)
Logical symbol mapping
Modulation symbol (binary indication: MSB, LSB)
Phase shift
0
-90°
1
+90°
Table 4-13: MSK (GSM)
Logical symbol mapping
Modulation symbol (binary indication: MSB, LSB)
Phase shift
0
+90°
1
-90°
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Fig. 4-28: MSK (for GSM and NATURAL) and DMSK Constellation Diagram including the symbol mapping
Similar to PSK, differential coding can also be used with MSK. In this case, too, the information is represented by the transition of two consecutive symbols. The block diagram of the coder is shown below.
Fig. 4-29: DMSK: differential encoder in the transmitter d i
input symbol {0;1} of differential encoder d i-1
input symbol delayed by the symbol period Ts d ' i
output symbol {0;1} of differential encoder
The logical symbol mapping is then performed on the XOR-coded bitstream d ' .
4.3.8 Quadrature Amplitude Modulation (QAM)
In the case of QAM the information is represented by the signal amplitude and phase.
The symbols are arranged in a square constellation in the I/Q plane.
To ensure reliable demodulation, symbol numbers should be distributed evenly with respect to the symbol alphabet.
As a rule of thumb, the result length should correspond to at least 8 times the modulation order. For example, with 64 QAM, a result length of at least 8*64 = 512 symbols should be used.
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QAM Mappings
The following QAM mappings are obtained from the mapping of the 1st quadrant, which is always rotated by π/2 for the subsequent quadrants and supplemented by a
(GRAY-coded) prefix for each quadrant.
Table 4-14: Derivation of QAM mappings
In the following diagrams, the symbol mappings are indicated in hexadecimal and binary form.
0 1 3 2
0000 0001 0011 0010
4
C
5
D
7
F
6
0100 0101 0111 0110
E
1100 1101 1111 1110
8 9 B A
1000 1001 1011 1010
Fig. 4-30: Constellation diagram for 16QAM (GRAY) including the logical symbol mapping (hexadecimal and binary)
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3
1011 1001 0001 0011
A
E
8
C
0
4
2
1010 1000 0000 0010
6
1110 1100 0100 0110
F D 5 7
1111 1101 0101 0111
Fig. 4-31: Constellation diagram for 16QAM including the logical symbol mapping for EDGE (hexadecimal and binary)
B 9 2 3
1011 1001 0010 0011
A 8 0
D C 4
1
1010 1000 0000 0001
6
1101 1100 0100 0110
F E 5 7
1111 1110 0101 0111
Fig. 4-32: Constellation diagram for 16QAM including the logical symbol mapping for DVB-C (hexadecimal and binary)
17 13 06 02
10111 10011 00110 00010
12 15 11 04 05 07
10010 10101 10001 00100 00101 00111
16 14 10 00 01 03
10110 10100 10000 00000 00001 00011
1B 19 18 08 0C 0E
11011 11001 11000 01000 01100 01110
1F 1D 1C 09 0D 0A
11111 11101 11100 01001 01101 01010
1A 1E 0B 0F
11010 11110 01011 01111
Fig. 4-33: Constellation diagram for 32QAM including the logical symbol mapping for DVB-C (hexadecimal and binary)
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2C 2E 26 24 08 09 0D 0C
2D 2F 27 25 0A 0B 0F 0E
29 2B 23 21 02 03 07 06
28 2A 22 20 00 01 05 04
34 35 31 30 10 12 1A 18
36 37 33 32 11 13 1B 19
3E 3F 3B 3A 15 17 1F 1D
3C 3D 39 38 14 16 1E 1C
001000 001001 001101 001100
001010 001011
000010 000011
001111 001110
000111 000110
000000 000001 000101 000100
Fig. 4-34: Constellation diagram for 64QAM including the logical symbol mapping for DVB-C (hexadecimal and binary); the binary form shows the upper right section of the diagram only.
0011010 0011011 0001011 0001010
0011000 0011001 0001001 0001000
0010000 0010001 0010101 0010100 0011100 0011101
0010010 0010011 0010111 0010110 0011110 0011111
0000010 0000011 0000111 0000110 0001110 0001111
0000000 0000001 0000101 0000100 0001100 0001101
1A 1B 0B 0A
18 19 09 08
10 11 15 14 1C 1D
12 13 17 16 1E 1F
02 03 07 06 0E 0F
00 01 05 04 0C 0D
Fig. 4-35: Constellation diagram for 128QAM including the logical symbol mapping (hexadecimal and binary); the figure shows the upper right sections of the diagram only
20 21 25 24 34 35 31 30
22 23 27 26 36 37 33 32
2A 2B 2F 2E 3E 3F 3B 3A
28 29 2D 2C 3C 3D 39 38
08 09 0D 0C 1C 1D 19 18
0A 0B 0F 0E 1E 1F 1B 1A
02 03 07 06 16 17 13 12
00 01 05 04 14 15 11 10
Fig. 4-36: Constellation diagram for 256QAM including the logical symbol mapping (hexadecimal); the figure shows the upper right section of the diagram only
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Fig. 4-37: Constellation diagram for 512QAM including the logical symbol mapping (hexadecimal); the figure shows the upper right section of the diagram only
Fig. 4-38: Constellation diagram for 1024QAM including the logical symbol mapping (hexadecimal); the figure shows the upper right section of the diagram only
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4.3.9 ASK
2ASK (OOK)
ASK stands for Amplitude Shift Keying, 2ASK (binary) is often also referred to as "On
Off Keying" (OOK). With this type of modulation, the information is solely represented by the absolute amplitude of the received signal at the decision points.
0 1
Fig. 4-39: Constellation diagram for 2ASK
4ASK
4ASK is a 4-ary Amplitude Shift Keying mapping type. With this type of modulation, the information is solely represented by the absolute amplitude of the received signal at the decision points.
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0 1 2 3
Fig. 4-40: Constellation diagram for 4ASK
4.3.10 APSK
With Amplitude Phase Shift Keying (APSK) modulation, the information is represented by the signal amplitude and the signal phase.
16APSK
A 8
2 0
6
R2
E
R1
C
4
F D
7 5
3 1
B 9
Fig. 4-41: Constellation diagram for 16APSK including the logical symbol mapping for DVB-S2
For DVB-S2 16APSK mappings, the ratio of the outer circle radius to the inner circle radius ( γ = R2/R1) depends on the utilized code rate and complies with
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4/5
5/6
8/9
9/10
Table 4-15: Optimum constellation radius ratio γ (linear channel) for 16APSK
Code Rate Modulation / coding spectral efficiency
γ
2/3
3/4
2.66
2.99
3.15
2.85
3.19
3.32
3.55
3.59
2.75
2.70
2.60
2.57
2/3
3/4
4/5
5/6
8/9
32APSK
For DVB-S2 32APSK mappings, the ratio of the middle circle radius to the inner circle radius ( γ
1
= R2/R1) and the ratio of the outer circle radius to the inner circle radius ( γ
2
depend on the utilized code rate and comply with table 4-16
.
Table 4-16: Optimum constellation radius ratios γ
1
and γ
2
(linear channel) for 32APSK
Code Rate Modulation / coding spectral efficiency
γ
1
γ
2
3.74
3.99
4.15
4.43
4.49
2.84
2.72
2.64
2.54
2.53
5.27
4.87
4.64
4.33
4.30
4.3.11 User-defined Modulation
In addition to the modulation types defined by the standards, modulation (including symbol mappings) can also be defined according to user requirements. In this case, the mapping is defined and stored in a specific format (*.vam file format) and then loaded to the VSA application. Modulation files in .vam format can be defined using a mapping wizard ("mapwiz"), an auxiliary tool provided by R&S via Internet free of charge. This tool is a precompiled MATLAB ® file (MATLAB pcode). To download the tool together with a detailed description see http://www.rohde-schwarz.com
(search term "mapwiz").
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4.4 Overview of the Demodulation Process
Fig. 4-42: Demodulation stages of the vector signal analysis option
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The figure 4-42 provides an overview of the demodulation stages of the vector signal
analysis option. The function blocks of the signal processing kernel can be found at the left (in grey) and their appropriate settings at the right (in blue).
A more detailed description of the most important stages is given in the following sections.
Burst Search
In this stage, the capture buffer is searched for bursts that comply with the signal description. The search itself can be switched on or off via the "Burst Search" dialog
(see "Enabling Burst Searches" on page 165). A list of the detected bursts is passed
on to the next processing stage.
I/Q Pattern Search
The "I/Q Pattern Search" is performed on the capture buffer. This means the VSA application modulates the selected pattern according to the transmit filter (Tx filter) and the modulation scheme. Subsequently, it searches the capture buffer for this I/Q pattern, i.e. the I/Q waveform of the pattern. It is assumed that patterns can only appear within bursts, i.e. the I/Q pattern search range is limited to the bursts detected by the burst search stage. If the burst search is switched off, the whole capture buffer is searched for the I/Q pattern. A list of all detected I/Q patterns is passed on to the next processing stage. It is important to note that the VSA application can only search for one pattern at a time.
The pattern search can be switched on or off via the "Pattern Search" dialog (see
"Enabling Pattern Searches" on page 167).
Detected patterns are indicated by a green background in the symbol table. (If, during demodulation, individual symbols do not match the pattern after all, these symbols are indicated by a red frame.)
Extraction of Result Range
The result range can be aligned to a burst, a pattern or simply the start of the capture buffer (see
"Reference" on page 174). Within this stage, the result range is cut from
the capture buffer starting at a point that is specified by the user, e.g. the start of a detected burst. The VSA application automatically takes into account filter settling times by making the internal buffers sufficiently longer than the selected result range.
Demodulation & Symbol Decisions
This stage operates on the extracted result range and aims at making the correct symbol decisions. Within this stage, a coarse synchronization of the carrier frequency offset, the carrier phase, the scaling and the timing takes place. Furthermore, an automatically selected internal receive filter (Rx filter) is used in order to remove the intersymbol interference as effectively as possible. The outputs of this stage are the
(coarsely) synchronized measurement signal and the symbol decisions (bits). The symbol decisions are later used for the "Pattern Symbol Check" stage and for the "Reference Signal Generation" stage.
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Pattern Symbol Check
The "I/Q Pattern Search" stage can only detect whether the similarity between the I/Q pattern and the capture buffer exceeds a certain threshold and, in this way, find the most likely positions where a pattern can be found.
Within this stage, the VSA application checks whether the pattern symbols (bits) really coincide with the symbol decisions at the pre-detected position. For example, if one out of 20 symbols does not coincide, the "I/Q Pattern Search" stage might detect this I/Q pattern, but the "Pattern Symbol Check" stage will decline it.
Note that this stage is only active if the pattern search is switched on.
If individual symbols do not match the pattern, these symbols are indicated by a red frame in the symbol table.
Reference Signal Generation
The ideal reference signal is generated based on the detected symbols and the specifications of the signal model, i.e. the modulation scheme and the transmit filter (Tx filter).
Measurement Filtering
Both the measurement signal and the reference signal are filtered with the specified measurement filter.
Synchronization
In this stage, the measurement signal and the reference signal are correlated. For
PSK, QAM and MSK modulated signals, an estimation algorithm is used in order to obtain estimates for the signal amplitude, signal timing, carrier frequency error, phase error, I/Q offset, gain imbalance, quadrature error and the amplitude droop. Alternatively, it is possible to disable the estimation algorithm.
For FSK modulated signals, estimates for the signal amplitude, signal timing, carrier frequency error, FSK deviation error and the carrier frequency drift are calculated. The measurement signal is subsequently corrected with these estimates. Compensation for
FSK deviation error and carrier frequency drift can be enabled or disabled.
For more information on synchronization see
●
chapter 4.5.1.2, "Estimation" , on page 101
●
chapter 5.9.2, "Advanced Demodulation (Synchronization)" , on page 180
Result Display
The selected measurement results are displayed in the window(s). Configuration of the windows can be performed via the "Window Configuration" dialog (see
"Display and Window Configuration" , on page 201).
4.4.1 Burst Search
The burst search is performed only if it is switched on. Otherwise, this stage is skipped.
It is recommended that you switch the burst search on if the signal is bursted. This
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Overview of the Demodulation Process ensures that all internal estimators are operated in time ranges where the burst power ramping is up.
In order to eliminate amplitude variations caused by noise or the modulation itself, the instantaneous power of the whole capture buffer is computed and then a moving average filter is applied. The length of this filter is automatically determined with the help of the user settings.
The filtered power of the capture buffer is subsequently compared to an automatically chosen threshold and the rising and falling edges of bursts are identified. With the help of the detected edges and some further processing, it is possible to decide whether the burst "candidates" comply with the user settings.
All bursts must have a length between ("Min Burst Length" – "Search Tolerance") and
("Max Burst Length" + "Search Tolerance") to be accepted. See "Burst Settings" on page 140 and
chapter 5.7.1, "Burst Search" , on page 164 for a more detailed
description of these parameters.
Fig. 4-43: Burst Search parameters
You can influence the robustness of the burst search directly by entering the correct
"Min Gap Length" on page 166). Refer to
illustration of the three parameters.
The detected bursts in the capture buffer for the current burst search settings are indicated by blue lines in the preview area of the "Burst Search" configuration dialog box
(see chapter 5.7.1, "Burst Search" , on page 164).
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Fig. 4-44: Burst search algorithm
4.4.2 I/Q Pattern Search
The I/Q pattern search is performed only if it is switched on. Otherwise, this stage is skipped. The main benefit of the I/Q pattern search is that it enables an alignment of the result range to the pattern. Furthermore, this stage can function as a filter: If the burst search and I/Q pattern search are switched on, and the parameter "Meas Only If
Pattern Symbols Correct" is set to true, only bursts with the correct pattern are
demodulated (see "Meas only if Pattern Symbols Correct" on page 168).
During the I/Q pattern search stage, the capture buffer is searched for an I/Q pattern by trying different time and frequency hypotheses. The I/Q pattern is generated internally, based on the specified symbol number of the pattern and the signal description
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(i.e. modulation scheme and transmit filter). The I/Q pattern search can also be referred to as the I/Q waveform. An I/Q pattern is considered detected if the correlation metric, i.e. the correlation value between the ideal I/Q pattern and capture buffer, exceeds a specified "I/Q Correlation Threshold" (see
"I/Q Correlation Threshold" on page 167.)
If the burst search is switched on, the I/Q pattern search only searches the I/Q pattern in bursts previously detected by the burst search. Furthermore, it only finds the first I/Q pattern within each burst. If the burst search is switched off, the I/Q pattern search searches for the I/Q pattern in the entire capture buffer.
The first detected pattern in the capture buffer for the current pattern search settings is indicated by a green line in the preview area of the "Pattern Search" configuration dialog box (see
chapter 5.7.2, "Pattern Search" , on page 166).
Predefined Patterns
Common standards usually have predefined pattern lists with standard-specific patterns. Patterns required for the current measurement can be selected from this list.
This list can be extended by patterns that are already available in the R&S FPS. Newly created patterns can also be added to the list.
4.4.3 Demodulation and Symbol Decisions
This stage operates on the result range and aims to make the correct symbol decisions. The algorithm is illustrated in
using the example of a QPSK modulation. After timing and scaling recovery, a frequency offset and phase offset estimator is employed.
After this coarse synchronization, the VSA application makes symbol decisions, i.e.
recovers which symbols were transmitted by the device under test (DUT).
Typically, the employed estimators are "non-data-aided" (NDA) estimators. This means that they operate on an unknown data sequence. Since the local oscillators (LO) of the transmitter (device under test) and the receiver (R&S FPS) are normally not coupled,
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Overview of the Demodulation Process their phase offset with respect to each other is unknown. The unknown transmission delay between DUT and R&S FPS adds a further unknown phase offset.
Due to this unknown phase offset, the result of the demodulation can be ambiguous with respect to the absolute phase position because of the rotational symmetry of e.g.
a PSK constellation. For example, in the case of non-differential QPSK modulation, the measurement signal, the reference signal and the decided I/Q symbols may have a constant phase offset of {0, π/2, π, or 3π/2}. This offset can only be detected and eliminated if a pattern was successfully detected at symbol level (see also
"Pattern Symbol Check" , on page 96).
If modulation types are used where the information is represented by the phase transition, e.g. differential PSK or MSK, the absolute phase position is not an issue. Thus, the ambiguity of the starting phase does not have an influence on the symbol decisions.
If the measurement signal contains a known pattern, it is also possible to use a "dataaided" (DA) estimator at this stage. This means that the estimator operates on a known data sequence, i.e. the pattern. If the signal contains a pattern, it is possible to choose between the above-described non-data-aided estimator and the data-aided estimator with the setting "
Coarse Synchronization : Pattern". If the data-aided estimator is
employed, the phase ambiguitiy can be resolved at this stage.
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Fig. 4-45: Demodulation and Symbol Decision algorithm
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4.4.4 Pattern Symbol Check
This stage performs a bit-by-bit comparison between the selected pattern and the demodulated bits. It is important to note that this comparison is only performed at positions that have been identified by the I/Q pattern search as possible pattern positions.
The algorithm and a simple example are illustrated in figure 4-46 .
First, the pattern candidate bits are extracted from the whole bitstream calculated by the "Demodulation & Symbol Decisions" stage. This means that the symbol stream is cut at the position that has been detected by the
I/Q Pattern Search as the start of the
pattern. The extracted sequence is then compared to the selected pattern.
If the demodulation has been ambiguous with respect to the absolute phase position, the extracted sequence needs to be compared to all possible rotated versions of the selected pattern. For example, in the case of QPSK modulation, the rotational symmetry has the order four, i.e. there are four pattern hypotheses. If the extracted sequence coincides with one of the hypotheses, the pattern is declared as "found" and the absolute phase corresponding to the appropriate hypothesis is passed on. Both the symbol decisions and the I/Q measurement signal are then rotated with this pattern phase (for the whole result range), thus resolving the phase ambiguity.
For more information refer to:
●
chapter 4.4.3, "Demodulation and Symbol Decisions" , on page 93
●
chapter 4.4.2, "I/Q Pattern Search" , on page 92
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Fig. 4-46: Pattern Symbol Check algorithm
4.4.5 The Equalizer
A possible source of high modulation errors of the DUT with PSK and QAM signals is a non-flat frequency response or ripple in frequency response within the modulation bandwidth.
This could be caused by the DUT's:
● Analog filter sections
● Digital filter sections, if a shortened filter length is used
● Digital arithmetic sections, if a shortened bit-length is used
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Fig. 4-47: General processing in the modulation- and demodulation stages
An equalizer filter with a reverse frequency response characteristic is able to compensate less distorted frequency responses in order to improve the modulation analysis results (see
Fig. 4-48: Compensation of the transfer function's error by inserting an equalizer in the receive path
For small distortions the reference signal can be determined correctly without preequalization. The equalizer can be calculated by comparing the reference signal and the measured signal and is only applied to the measured signal. This is referred to as
normal equalizer mode. Note that the resulting equalizer function is not simply the inverted distortion function.
For more complex distortions the reference signal might not be determined correctly due to wrong symbol decisions. Despite the resulting imperfect equalizer calculation, the estimated equalizer is often good enough to improve the reference signal creation in the succeeding sweep. Thus, the new equalizer is improved successively. This processing mode of the equalizer is called tracking mode. After only few sweeps, the results are sufficiently accurate and the learning phase is completed. Then the equalizer can be used without additional calculations as long as the input signal remains stable. If an unstable input has led to an unusable equalizer filter, reset the equalizer with the "Reset" button.
Fig. 4-49: An equalizer filter can be activated in the reference and measurement signal path. The filter coefficients are determined in such a way that the error vector magnitude (EVM) is minimized.
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The result range used for equalizer calculation might be quite short leading to unstable equalizer impulse responses. For time-invariant channels the estimation length can be extended using Averaging mode. In this case, the statistics from all previously determined reference signals and measurement signals are averaged to determine the current equalizer function. Thus, the results of previous sweeps are continuously considered to calculate the current equalizer values. Averaging is only restarted when the
R&S FPS is switched off or when the user manually resets the equalizer. Obviously, this method requires a stable input signal for the entire duration of the measurement, as otherwise the current equalizer is distorted by previous results.
This process requires extended calculation time so that the measurement update rate of the R&S FPS decreases distinctly. When the distortions are compensated sufficiently, this averaging process can be stopped. The current filter is frozen, that means it is no longer changed.
Keep in mind that in Tracking and Averaging mode for sweep counts > 1 repeated analysis of past result ranges might lead to differing readings.
The equalizer algorithm is limited to PSK and QAM modulation schemes, as the optimization criterion of the algorithm is based on minimizing the mean square error vector magnitude. Thus it cannot be used for FSK modulation.
User-defined equalizers
Instead of tracking equalizer values repeatedly for different input signals, you can store existing values to a file and load them again later. This is useful if signals from the same input source are measured frequently. In this case, you only have to perform a calculation once and can use the same equalizer filter again and again.
Filter length
The length of the equalizer can be defined in symbols. The longer the equalizer the higher the resolution in the frequency domain is and the more distortion can be compensated. The shorter the filter length, the less calculation time is required during the equalizer's tracking or averaging phase.
Estimation points per symbol
You can define how many sample points are used for the equalizer calculation at each symbol ("Estimation points per symbol", see
chapter 4.7, "Display Points vs Estimation
Points per Symbol" , on page 121). Typically, this is one point per symbol (= symbol
rate) or a factor of 2.
Channel EVM
The equalizer not only compensates for distortions in the measurement signal, but also improves the accuracy of the estimated ideal reference signal. Thus, it is usually recommendable to enable the equalizer once you have analyzed the original input signal on the R&S FPS. By default, the error results are calculated using the compensated values if the equalizer is enabled. However, you can disable the compensation for channel results in order to analyze the actual error values obtained from the distorted channel.
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Signal Model, Estimation and Modulation Errors
4.5 Signal Model, Estimation and Modulation Errors
This section describes the signal and error models used within the VSA application.
The estimation algorithms used to quantify specific modulation errors are then outlined.
The descriptions vary depending on the modulation type.
4.5.1 PSK, QAM and MSK Modulation
4.5.1.1
Error Model
Fig. 4-50: Modelling Modulation Errors
The measured signal model for PSK, QAM and MSK modulation is shown in
figure 4-50 and can be expressed as:
MEAS
g
I
REF
I
c
I
j
g
Q
REF
Q
c
Q
e j
e j
2 f
0 t t n ( t ) where:
REF
I
(t) and REF
Q
(t): the inphase and quadrature component of the reference signal g
I
and g
Q
: the effects of the gain imbalance c
I
and c
Q
: the effects of an I/Q offset
ϑ: the quadrature error
α: the amplitude droop
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0
: the carrier frequency offset
φ: the carrier phase offset
Շ: the timing offset n(t): a disturbing additive noise process of unknown power
4.5.1.2
Estimation
The VSA application includes two synchronization stages. The first stage has already been described in the context of the "Demodulation & Symbol Decisions" block (see
chapter 4.4.3, "Demodulation and Symbol Decisions" , on page 93).
The second stage is realized within the "Synchronization" block. Here, the measurement signal is matched to the reference signal by minimizing the mean square of the error vector magnitude. This is done by selecting the optimum parameter vector :
arg min
t
MEAS
REF
2
The minimization takes place at the sample instants specified by the Estimation
t n T
E with T
E
: the sampling period used for estimation
Subsequently, the measurement signal is corrected with the determined parameter vector. Note that with a subset of the parameters, you can enable or disable correction
(see chapter 5.9.1, "Demodulation - Compensation" , on page 176).
Estimation ranges
The "estimation ranges" are determined internally according to the signal description:
● For continuous signals, the estimation range corresponds to the entire result range, since it can then be assumed that the signal consists of valid modulated symbols at all time instants.
● For bursted signals, the estimation range corresponds to the overlapping area of the detected burst and the "Result Range". Furthermore, the Run-In/Run-Out ranges (see
"Burst Settings" on page 140) are explicitly excluded from the estima-
tion range.
In the special case that the signal is indicated as a "burst signal", but is so highly distorted that the burst search cannot detect a burst, the estimation range corresponds to the pattern and (if an offset of the pattern is indicated) the useful part of the burst from its start to the pattern start.
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4.5.1.3
Modulation Errors
Error vector (EV)
Measurement Basics
Signal Model, Estimation and Modulation Errors
Fig. 4-51: Modulation error: error vector
The error vector is the difference between the measurement signal vector (Meas vector) and the reference signal vector (Ref vector).
Error Vector Magnitude (EVM)
Fig. 4-52: Modulation error: EVM, magnitude error, phase error
The magnitude of the error vector in the diagram is specified as the error vector magnitude (EVM). It is commonly normalized to the mean reference power, or alternatively to the maximum reference power or the mean or maximum constellation power (power at
the symbol instants, see "Normalize EVM to" on page 181). The EVM should not be
confused with the magnitude error, see below.
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Magnitude Error
The magnitude error is defined as the difference between the measurement vector magnitude and the reference vector magnitude (see
).
Phase Error
Fig. 4-53: Modulation error: Phase error, error vector phase
The phase error is the phase difference between the measurement vector and the reference vector.
PHASE _ ERR
PHASE
MEAS
PHASE
REF
This measurement parameter is of great importance for MSK modulation measurements.
The phase error should not be confused with the error vector phase. The error vector phase is the absolute phase of the error vector (see
The effects of the different modulation errors in the transmitter on the result display of the analyzer are described in the next topics. All diagrams show the equivalent, complex baseband signal.
Modulation Error Ratio (MER)
The modulation error ratio (MER) is closely related to EVM:
MER 20 log
10
( EVM ) dB where the EVM is normalized to the mean reference power.
Symbol Rate Error (SRE)
The symbol rate error (SRE) describes the difference between the defined (reference) symbol rate and the currently measured symbol rate in relation to the reference symbol rate. The value is given in parts per million (ppm).
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SRE
SR
Meas
SR
SR
Re f
Re f
Currently, the SRE is only calculated for PSK, QAM and User QAM modulation, and
Example:
For a defined symbol rate of SR
Ref
SR
Meas
= 1 MHz, and a measured symbol rate of
= 999.9 kHz, the symbol rate error is:
SRE = [(999.9-1000) / 1000 ] * 1 000 000 ppm = -100 ppm
I/Q Offset (Origin Offset)
Fig. 4-54: Effect of an I/Q or origin offset after demodulation and error compensation
The effect of an I/Q offset in the transmitter is shown in
.
The I/Q offset can be compensated for if the corresponding option is selected in the demodulation settings. In this case, the offset does not affect the EVM.
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Example:
The following figures compare the results for a compensated I/Q offset of 2.5% and a non-compensated offset.
I/Q Offset compensated for I/Q Offset NOT compensated for
Gain Imbalance
Fig. 4-55: Effect of gain imbalance
The gain difference in the I and Q channels during signal generation in the transmitter is referred to as gain imbalance. The effect of this error on the constellation diagram
and the unit circle are shown in figure 4-55 . In the example, the gain in the I channel is
slightly reduced which causes a distortion of coordinates in the I direction. The unit circle of the ideal constellation points has an elliptic shape.
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The gain imbalance can be compensated for if the corresponding option is selected in the demodulation settings. In this case, the imbalance does not affect the EVM.
Note that the gain imbalance is not estimated (and cannot be compensated for) in a
BPSK signal.
Preconditions for Gain Imbalance and Quadrature Error measurements
The distortions "gain imbalance" and "quadrature error" can only be measured without ambiguity, if the following two conditions are fullfilled:
● a pattern is detected
● the modulation is a non-differential, non-rotating QAM or PSK
Otherwise, only the measurement parameter "I/Q Imbalance", which is a combination of the gain imbalance and the quadrature error, is significant.
Quadrature Error
Fig. 4-56: Effect of Quadrature Error
The quadrature error is another modulation error which is shown in
In this diagram, the I and Q components of the modulated carrier are of identical amplitude but the phase between the two components deviates from 90°.
This error also distorts the coordinates. In the example in
figure 4-56 , the Q-axis is shif-
ted.
Note that the quadrature error is not estimated (and cannot be compensated for) in a
BPSK signal.
I/Q Imbalance
The effect of quadrature error and gain imbalance are combined to form the error parameter I/Q imbalance.
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B g
I g
I
g
Q
e j
g
Q
e j where g
I
and g
Q
are the gain of the inphase and the quadrature component and θ represents the quadrature error.
The I/Q imbalance can be compensated for if the corresponding option is selected in the demodulation settings. In this case, the I/Q imbalance does not affect the EVM.
Note that the I/Q imbalance is not estimated (and cannot be compensated for) in a
BPSK signal.
Amplitude Droop
The decrease of the signal power over time in the transmitter is referred to amplitude droop.
1.2
1
0.8
0.6
0.4
0.2
0
0 50 100
Time (Symbols)
150 200
Fig. 4-57: Effect of amplitude droop
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Gain Distortion
Table 4-17: Effect of nonlinear amplitude distortions
Nonlinear distortions: amplitude distortion (transmitter)
Amplitude distortion (analyzer)
The effect of nonlinear amplitude distortions on a 64QAM signal are illustrated in
table 4-17 (only the first quadrant is shown). The transfer function is level-dependent:
the highest effects occur at high input levels while low signal levels are hardly affected.
The signal is scaled in the analyzer so that the average square magnitude of the error vector is minimized. The second column shows the signal after scaling.
Table 4-18: Amplitude transfer functions
Amplitude transfer function (transmitter) Amplitude transfer function (analyzer)
A logarithmic display of the amplitude transfer functions is shown in table 4-18
. The analyzer trace is shifted against the transmitter trace by this scale factor.
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Phase Distortion
Table 4-19: Effect of nonlinear phase distortions
Nonlinear distortions: phase distortion (transmitter) Phase distortion (analyzer)
The effect of nonlinear phase distortions on a 64QAM signal is illustrated in table 4-19
(only the first quadrant is shown). The transfer function is level-dependent: the highest effects occur at high input levels while low signal levels are hardly affected. These effects are caused, for instance, by saturation in the transmitter output stages. The signal is scaled in the analyzer so that the average square magnitude of the error vector is minimized. The second column shows the signal after scaling.
Table 4-20: Phase transfer functions
Nonlinear distortions: phase distortion (transmitter) Phase distortions (analyzer)
A logarithmic display of the phase transfer functions is shown in table 4-20 . The ana-
lyzer trace is shifted by the phase described above as against the transmitter trace.
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Noise
Measurement Basics
Signal Model, Estimation and Modulation Errors
Fig. 4-58: Additive noise
A 64QAM signal with additive noise is shown in
(only the first quadrant is shown). The symbol decision thresholds are also shown.
The noise signal forms a "cloud" around the ideal symbol point in the constellation diagram. Exceeding the symbol decision boundaries leads to wrong symbol decisions and increases the bit error rate.
Similar displays are obtained in case of incorrect transmitter filter settings. When an incorrect filter is selected, crosstalk occurs between neighbouring symbol decision points instead of the ISI-free points. The effect increases the more the filtering deviates from actual requirements.
The two effects described cannot be distinguished in the Constellation I/Q diagram but in statistical and spectral analyses of the error signal.
Channel (transmission) distortion
During transmission, disturbances in the transmission channel may cause distortions in the input signal at the R&S FPS. Such influences are included in the EVM calculation.
However, if the ideal (reference) signal can be estimated with sufficent accuracy by the
R&S FPS (e.g. using the equalizer), the channel distortions can be compensated for and deducted from the EVM.
4.5.2 FSK Modulation
Signal Model
Frequency shift keying (FSK) involves the encoding of information in the frequency of a transmitted signal. As opposed to other modulation formats such as PSK and QAM, the FSK process is a non-linear transformation of the transmitted data into the transmitted waveform.
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A sequence of symbols {s i
} are modulated using a "frequency pulse" g(t) to form the instantaneous frequency of the transmitted complex baseband waveform, denoted by f
REF
(t) and defined as: f
REF
h
i s i g
t i T
where f
Symb
=1/T is the symbol rate and h is a scaling factor, termed the modulation index. The transmitted (or reference) FSK signal is formed by frequency modulation of the instantaneous frequency:
REF
e j 2 t
f
REF
du
e j
REF where φ
REF
(t) denotes the phase of the transmitted waveform. In the VSA application a continuous phase FSK signal is assumed, which is ensured by the integral in the expression for REF(t). A graphical depiction of the reference waveform generation is shown below in
Fig. 4-59: Reference complex baseband FSK signal generation
Reference Deviation
The transmitted symbols {s i
} are assumed to be chosen from a finite and real-valued constellation of M values; { ς
1
, ς
2
,..., ς
M
}. The maximum absolute constellation point is denoted by ς
MAX
. The maximum phase contribution of a data symbol is given by:
MAX
2 h
MAX
g
dt
The reference deviation of the FSK signal is defined as:
REF
2
MAX
T
1
T h
MAX
g
dt
In the VSA application the frequency pulse filter is normalized such that:
g
dt
1
2
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The constellation for M FSK is assumed to be { ±1, ±3, ..., ±(M-1)}, which implies ς
MAX
=
M-1. The expression for the
in terms of the modulation index is therefore given by:
REF
1
2
h
M 1
f
Symb
The above formula provides the necessary calculation for measurement of an FSK signal with known symbol rate and modulation index.
Calculation examples:
The GSM standard describes the transmission of binary data using MSK (i.e. 2FSK) modulation with a modulation index of h=1/2 at a symbol rate of 270.8333 KHz. The reference deviation is therefore given by:
REF
1
2
1
2
2 1
270.8333
kHz
67.7083
kHz
The APCO Project 25 standard (phase 2) defines a H-CPM signal (i.e. 4FSK) with a modulation index of h=1/3 and a symbol rate of 6 KHz. The reference deviation is:
REF
1
2
1
3
4 1
6 kHz
3 kHz
4.5.2.1
Error Model
The FSK measurement model used assumes that signal distortions in both the magnitude and phase/frequency are present, as well as additive noise. The measured signal model is expressed as:
MEAS A
DIST
e j
DIST
n with
n(t) is a disturbing additive noise process of unknown power,
A
DIST
(t) is the distorted magnitude model and
φ DIST(t) is the distorted phase model.
The magnitude model is given by:
A
DIST
K e
t with
K is a constant scaling factor which can be interpreted as the system gain and
⍺ is the amplitude droop in Nepers per second.
The phase model is given by:
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DIST
B
REF
C t 1
2
D t
2 with
B is a scaling factor which results in a reference deviation error,
C is a carrier frequency offset in radians per second,
D is a frequency drift in radians per second per second,
τ is a timing offset in seconds and ϕ is a phase offset in radians.
For the above phase model, an equivalent frequency distortion model may be expressed as: f
DIST
B f
REF
f
0
f d
t with
B is the scaling factor which results in a reference deviation error, f
0
=C/(2 ·π) is a carrier frequency offset in Hz, f
0
=D/(2 ·π) is a frequency drift in Hz per second and
τ is the timing offset in seconds.
The measured signal model in terms of the instantaneous frequency and all distortion parameters is given by:
MEAS
K e
t e j e j 2
B t
f
REF
du f
0
t 1
2 f d
t 2
n
4.5.2.2
Estimation
The estimation of the distortion parameters listed previously is performed separately
for the magnitude and phase/frequency distortions, as illustrated in figure 4-60 . It is
noted that the estimation of the timing offset is performed only on the frequency of the signal, as the reference magnitude is assumed to be constant over the estimation
range. For details on the estimation range, see "Estimation ranges" on page 101.
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Fig. 4-60: FSK Estimation Strategy
In
MEAS(n) denotes the sampled (complex baseband) measured signal waveform. The magnitude samples are denoted A
MEAS
(n), while the instantaneous frequency samples of the measured and reference signals are denoted by f
MEAS
(n) and f
REF
(n) respectively. The dashed outline of the "Meas Filter" block indicates that this operation is optionally (de-) activated based on the corresponding user settings (see
For the estimation of the magnitude parameters, the following least-squares criterion is minimized:
C
MAG
K ,
n
A
MEAS
K e
n T
E
2 with respect to the model parameters K and ⍺, where T
E
denotes the sampling period
used for estimation (see "Estimation Points/Sym" on page 182).
For estimation of the frequency parameters, the following least-squares criterion is minimized:
C
FREQ
B , f
0
, f d
,
n f
MEAS
B f
REF
f
0
f d
n T
E
2 with respect to the model parameters B, f
0
, f d
and τ. The term denotes the reference instantaneous frequency with a (possibly fractional) delay of samples.
For FSK modulation the default sampling period used for estimation is the capture sampling period.
4.5.2.3
Modulation Errors
A 2FSK signal is generated using a GMSK frequency pulse. Examples of carrier drift
and reference deviation are shown in figure 4-61 and
, respectively.
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Carrier frequency drift
A carrier frequency drift is modeled as a linear change in the carrier frequency with respect to time. The effect of carrier drift on the instantaneous frequency of an FSK signal is illustrated in
.
Fig. 4-61: The reference and distorted instantaneous frequency of a GMSK signal with a carrier frequency drift
FSK deviation error
The FSK deviation error is the difference between the measured frequency deviation and the reference frequency deviation as entered by the user (see
(FSK only)" on page 137). The evidence of a deviation error in the instantaneous fre-
quency of an FSK signal is demonstrated in
.
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Fig. 4-62: The reference and measured instantaneous frequency of a GMSK signal with reference deviation error
4.6 Measurement Ranges
The VSA application contains three measurement ranges that need to be set by the user:
● Capture Buffer Length
The length of the capture buffer specifies how many data points are captured during a single VSA measurement.
For example, if you want to measure a bursted signal, it is recommended that you make the capture length long enough to ensure that in each capture buffer at least one entire burst is included.
The maximum capture buffer length is 50 Msymbols (for a sample rate of 4) or 200 million samples.
● Result Range
The result range defines the symbols from the capture buffer that are to be demodulated and analyzed together.
For example, bursted signals have intervals between the bursts that are not of interest when analyzing peaks or overshoots. Thus, the result range usually coincides with the range of the capture buffer in which the burst is located.
The maximum result range length is 64 000 symbols (for a sample rate of 4) or 256
000 samples.
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● Evaluation Range
The evaluation range defines the symbols from the result range that are to be included in the evaluation of specific parameters, e.g. error vectors.
For example, while you may want to display the ramps of a burst and thus include them in the result range, they do not contribute to the error vectors or power levels.
Thus, you would not include them in the evaluation range.
Fig. 4-63: Schematic overview of Capture Length, Result Range, and Evaluation Range
The determined result and evaluation ranges are included in the result displays (where useful) to visualize the basis of the displayed values and traces.
4.6.1 Result Range
The result range defines the symbols from the capture buffer that are to be demodulated and analyzed together.
In some cases, the data in the capture buffer contains parts that are not relevant for the evaluation task at hand. Thus, you can exclude them from the result range (see
chapter 5.8, "Result Range Configuration" , on page 173).
Result range display
The result ranges are indicated by green bars along the time axis of the capture buffer result diagrams.
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Fig. 4-64: Result ranges for a burst signal
Result displays whose source is not the capture buffer are based on a single result range, such as the "EVM vs. Time" display or the data in the "Current" column of the
Result Summary. In this case, you can use the capture buffer display to navigate
through the available result ranges ( Select Result Rng
function), and analyze the individual result ranges in separate windows. The currently displayed result range is indicated by a blue bar in the capture buffer display.
You can change the position of the result range quickly and easily by dragging the blue bar representing the result range to a different position in the capture buffer.
Continuous and discrete result ranges
Depending on the type of signal and your result range definition, the result ranges may be continuous or discrete. Bursted signals commonly have several discrete result ranges at the bursts, with intervals during the noise periods which should not be included in the results (see
Continuous signals, on the other hand, have result ranges that cover the entire or a specific part of the capture buffer without intervals.
Fig. 4-65: Result ranges for a continuous signal
Result Range Length
The result range length is defined by the number of symbols that are to be demodulated. All traces over time are displayed over the result range. For example, if you have a
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Measurement Ranges burst of 100 symbols and you define the result length as 200 symbols, you can examine the burst ramps in detail (by selecting the alignment "Burst - Center").
The maximum result length is 64 000 symbols (for a sample rate of 4) or 256 000 samples.
Result Range Alignment
By defining the number of the symbol which marks the beginning of the alignment reference source (burst, capture buffer or pattern), you can define an offset of the x-axis
(in addition to the one defined for the signal structure, see
For example, if you align the result to the center of the pattern and set the "Symbol
Number at Pattern Start" to "0", you can easily find the pattern start in the EVM measurement simply by moving a marker to the symbol number "0".
When you define the "Symbol Number at <Reference> Start" remember to take the off-
set defined for the signal structure into consideration (see "Offset" on page 141). If you
define an offset of the pattern with respect to the useful part of the burst in the signal description and align the result to the pattern, the "Symbol Number at Pattern Start" refers to the first symbol of the useful part of the burst, not the first symbol of the pattern.
Run-In / Run-Out Time
The parameter Run-In/-Out can be used to influence the range over which the EVM is minimized. The (internal) synchronization range is the overlapping area of the result range and the burst excluding its Run-In/-Out areas. Hence, this parameter also allows for demodulation of bursts with mixed modulations, e.g. Bluetooth, because it can be used to explicitely exclude symbols from influencing the synchronization.
Useful length
The burst excluding its Run-In/-Out areas is sometimes referrred to as the "useful part". The minimum length of the useful part (= Min Length - Run-In - Run-Out) must be ≧10.
Remote commands:
A remote command is provided to determine the position of the current result range within the capture buffer:
[SENSe:]DDEMod:SEARch:MBURst:STARt?
4.6.2 Evaluation Range
In some scenarios, the result range contains symbols that are not supposed to be considered for the EVM or other calculated parameters that are displayed in the Result
Summary.
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For example, while you may want to display the ramps of a burst and thus include them in the result range, they do not contribute to the error vectors or power levels.
Thus, you would not include them in the evaluation range.
(See also
chapter 9.3.5, "Setting the Evaluation Range" , on page 241.)
The evaluation range is always equal to or smaller than the result range and defines:
● The range over which traces that do not have a time axis are displayed, e.g. polar diagrams
● The range over which the following parameters are calculated for the Result Summary: EVM, MER, Phase Error, Magnitude Error, Power
Evaluation range display
In all displays over time, except for capture buffer displays, the evaluation range is indicated by red lines.
Fig. 4-66: Evaluation lines in absolute magnitude diagram
In symbol tables, the evaluated symbols are indicated by red square brackets.
In other result displays that are based on the evaluation range only, two red vertical lines are displayed in the diagram header to indicate a limited evaluation basis.
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Display Points vs Estimation Points per Symbol
4.7 Display Points vs Estimation Points per Symbol
Estimation points per symbol
During synchronization, the measurement signal is matched to the reference signal and various signal parameters are calculated, as well as the optional equalizer. You can define how many sample points are used for this calculation at each symbol. Typically, this is one point per symbol (= symbol rate) or a factor of 4 (= sample rate).
Display points per symbol
The number of points per symbol used for calculation may vary from the number of points used to display the results of the calculation. If more points per symbol are selected than the defined sample rate, the additional points are interpolated for the display. The more points are displayed per symbol, the more detailed the trace becomes,
.
Fig. 4-67: Result display with different numbers of points per symbol: window A = 1; window B = 2; window C = 4; window D = 16;
The displayed points per symbol also determine how many values are returned when the trace data is queried by a remote command (see
For results based on the capture buffer, one display point is displayed for each sample taken, i.e. the display points per symbol are always identical to the sample rate.
For the "Result Summary", the number of display points corresponds to the estimation points per symbol. (By default, 1 for QAM and PSK modulated signals and the sample
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Capture Buffer Display rate for MSK and FSK modulated signals.) This value also controls which samples are considered for the peak and RMS values and the power result.
For all other result displays, the default number of displayed points per symbol is identical to the sample rate.
4.8 Capture Buffer Display
In previous firmware versions, the capture length in the R&S FPS VSA application was restricted to 256,000 samples. As of firmware version 2.00, up to 200 million symbols can be captured and processed at a time.
Processing large numbers of samples
If more than 256,000 samples are captured, overlapping capture ranges with a size of
256,000 samples each are created.
The maximum number of symbols that can be captured depends on the specified number of samples per symbol; for example, for the default sample rate of 4*symbol rate, the maximum number of symbols to be captured is 50,000,000 (see also
"Sample Rate, Symbol Rate and I/Q Bandwidth" , on page 63).
Only one capture range at a time can be displayed in the result displays based on the capture buffer (except for the
). You can scroll through the different ranges using the
Select Result Rng function. When the selected result
range moves outside the current capture range, the right edge of the current result range is displayed in the center of the next capture range.
Overview vs. details
While the
and other result displays based on the capture buffer
,
chapter 3.2.11, "Frequency Absolute" , on page 29) can
only display a single capture range at a time, the Magnitude Overview Absolute
displays the entire capture buffer at once. However, the overview trace is restricted to
25,000 points. If necessary, the captured samples are mapped to 25,000 display points using an autopeak detector for display in the Magnitude Overview Absolute diagram.
Thus, this result display is not suitable to detect transient effects or analyze individual symbols closely. For these purposes, the Magnitude Absolute result display is suited better, where one display point can be displayed for each sample taken.
Restrictions
Trace modes that calculate results for several sweeps (Average, MinHold, MaxHold) are applied to the individual ranges in the capture buffer diagrams and thus may not provide useful results. For the Magnitude Overview Absolute result display, these trace modes are not available at all. Furthermore, only one trace can be configured in the
Magnitude Overview Absolute result display.
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Known Data Files - Dependencies and Restrictions
Remote commands:
Remote commands are provided to determine the first and last values currently displayed in a particular window:
DISPlay[:WINDow<n>]:TRACe<t>:X[:SCALe]:STARt?
DISPlay[:WINDow<n>]:TRACe<t>:X[:SCALe]:STOP?
And to determine the position of the current result range within the capture buffer:
[SENSe:]DDEMod:SEARch:MBURst:STARt?
4.9 Known Data Files - Dependencies and Restrictions
For various vector signal analysis functions the measured signal is compared to a defined ideal reference signal. The more precise the reference signal, the more precise the results become. In the best case, the possible data sequences within the signal to analyze are known in advance and can be used to compare the measured data to.
This is similar to defining a pattern for the entire result range. Thus, a falsely estimated reference signal (due to false symbol decisions) is avoided and does not influence the error calculation.
You can load xml files containing the possible sequences to the VSA application and use them to compare the measured data to. In particular, you can use known data for the following functions:
● Fine synchronization during the demodulation process (see
and
● Calculation of the Bit Error Rate (BER), see chapter 3.2.1, "Bit Error Rate (BER)" , on page 20
For details on working with Known Data files see
Known Data Files" , on page 218
Auxiliary tool to create Known Data files
An auxiliary tool to create Known Data files from data that is already available in the
VSA application is provided with the R&S FPS free of charge.
See
chapter 8.2.3.2, "How to Create Known Data Files" , on page 219.
The syntax for Known Data files is described in chapter A.5, "Known Data File Syntax
When you use Known Data files as a reference, some dependencies to other settings and restrictions for other functions apply.
Modulation Order
The "Modulation Order" selected in the "Modulation" settings in the VSA application must correspond to the modulation order value specified in the xml file (<ModulationOrder> element).
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VSA in MSRA Operating Mode
Demodulation
Demodulation using synchronization to the Known Data may increase the measurement duration, as each detected symbol must be compared to each possible sequence in the data file.
Result Length
The "Result Length" specified in the "Result Range" dialog box in the VSA application must be identical to the length of the specified symbol sequences in the xml file
(<ResultLength> element).
Result Range Alignment
● Bursted signals
When you align the result range to a bursted signal, due to the uncertainty of the burst search, the determined result range might start up to 2 symbols before or after the actual burst. However, an offset of only one symbol has the effect that none of the predefined symbol sequences in the Known Data file will be found. To avoid this, try one of the following:
– Align the result range to a pattern instead of the burst.
– Use a precise external trigger and align the result range to the capture buffer.
This requires a very precise trigger timing, otherwise the result range start may be incorrect again.
● Continuous signals
For continuous signals without a pattern, the result range is aligned randomly.
Thus, a very large number of possible sequences must be predefined.
Use a precise external trigger and align the result range to the capture buffer. This requires a very precise trigger timing, otherwise the result range start may be incorrect again.
4.10 VSA in MSRA Operating Mode
The R&S FPS VSA application can also be used to analyze data in MSRA operating mode.
In MSRA operating mode, only the MSRA Master actually captures data; the MSRA applications receive an extract of the captured data for analysis, referred to as the
application data. For the R&S FPS VSA application in MSRA operating mode, the application data range is defined by the same settings used to define the signal capture in Signal and Spectrum Analyzer mode. In addition, a capture offset can be defined, i.e. an offset from the start of the captured data to the start of the application data for vector signal analysis. The "Capture Buffer" displays show the application data of the VSA application in MSRA mode.
Data coverage for each active application
Generally, if a signal contains multiple data channels for multiple standards, separate applications are used to analyze each data channel. Thus, it is of interest to know which application is analyzing which data channel. The MSRA Master display indicates
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VSA in MSRA Operating Mode the data covered by each application, restricted to the channel bandwidth used by the corresponding standard, by vertical blue lines labeled with the application name. Since the VSA application supports several standards and the standard used by the currently analyzed data is not known, the "Symbol Rate" defined in the "Signal Description" settings is used to approximate the channel bandwidth.
Analysis interval
However, the individual result displays of the application need not analyze the complete data range. The data range that is actually analyzed by the individual result display is referred to as the analysis interval.
In the R&S FPS VSA application the analysis interval is automatically determined according to the evaluation range or result range settings, as in Signal and Spectrum
Analyzer mode. The currently used analysis interval (in seconds, related to capture buffer start) is indicated in the window header for each result display.
Exception: Equalizer
In the "Equalizer" displays do not indicate the analysis interval in MSRA mode.
Analysis line
A frequent question when analyzing multi-standard signals is how each data channel is correlated (in time) to others. Thus, an analysis line has been introduced. The analysis line is a common time marker for all MSRA applications. It can be positioned in any
MSRA application or the MSRA Master and is then adjusted in all other applications.
Thus, you can easily analyze the results at a specific time in the measurement in all applications and determine correlations.
If the marked point in time is contained in the analysis interval of the application, the line is indicated in all time-based result displays, such as time, symbol, slot or bit diagrams. By default, the analysis line is displayed, however, it can be hidden from view manually. In all result displays, the "AL" label in the window title bar indicates whether or not the analysis line lies within the analysis interval or not:
● orange "AL": the line lies within the interval
● white "AL": the line lies within the interval, but is not displayed (hidden)
● no "AL": the line lies outside the interval
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VSA in MSRA Operating Mode
For details on the MSRA operating mode see the R&S FPS MSRA User Manual.
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5 Configuration
Using the VSA application you can perform vector signal analysis measurements using predefined standard setting files, or independently of digital standards using userdefined measurement settings. Such settings can be stored for recurrent use.
Thus, configuring VSA measurements requires one of the following tasks:
● Selecting an existing standard settings file and, if necessary, adapting the measurement settings to your specific requirements.
● Configuring the measurement settings and, if necessary, storing the settings in a file.
VSA application
When you switch the application of a measurement channel to VSA the first time, a set of parameters is passed on from the currently active application (see
"Default Settings for Vector Signal Analysis" , on page 128). After initial setup, the
parameters for the measurement channel are stored upon exiting and restored upon re-entering the channel. Thus, you can switch between applications quickly and easily.
When you activate a measurement channel for the VSA application, a VSA measurement for the input signal is started automatically with the default configuration. The
"VSA" menu is displayed and provides access to the most important configuration functions.
Automatic refresh of preview and visualization in dialog boxes after configuration changes
The R&S FPS supports you in finding the correct measurement settings quickly and easily - after each change in settings in dialog boxes, the preview and visualization areas are updated immediately and automatically to reflect the changes. Thus, you can see if the setting is appropriate or not before accepting the changes.
Importing and Exporting I/Q Data
The I/Q data to be evaluated in VSA can not only be measured by the VSA application itself, it can also be imported to the application, provided it has the correct format. Furthermore, the evaluated I/Q data from the VSA application can be exported for further analysis in external applications.
The import and export functions are available in the "Save/Recall" menu which is displayed when you select the "Save" or "Open" icon in the toolbar.
For details on importing and exporting I/Q data see the R&S FPS User Manual.
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Default Settings for Vector Signal Analysis
5.1 Default Settings for Vector Signal Analysis
When you switch the application of a measurement channel to VSA the first time, a set of parameters is passed on from the currently active application:
● center frequency and frequency offset
● reference level and reference level offset
● attenuation
● signal source and digital I/Q input settings
● input coupling
After initial setup, the parameters for the measurement channel are stored upon exiting and restored upon re-entering the channel. Thus, you can switch between applications quickly and easily.
Apart from these settings, the following default settings are activated directly after a measurement channel has been set to VSA, or after a
:
Table 5-1: Default settings for VSA channels
Parameter Value
Digital standard
Sweep mode
Trigger settings
Trigger offset
Modulation
Transmit filter
Measurement filter
Signal type
Symbol rate
Sample rate
Capture length
Usable I/Q Bandwidth
Result length
Result Range alignment
3G_WCDMA
CONTINUOUS
FREE RUN
0
QPSK, WCDMA mapping
RRC, α=0.22
= Transmit filter
Continuous, no pattern
3.84 MHz
4* Symbol rate (=15.36 MHz)
8000 symbols
12.228 MHz
800 symbols
Left at capture buffer start
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Configuration According to Digital Standards
Parameter
Evaluation range
Demodulation
Evaluations
Display points per symbol
Value
Entire result range
Compensation for I/Q offset and amplitude droop
Estimation points per symbol: auto (1)
Window 1: Constellation I/Q (Meas & Ref)
Window 2: Result Summary
Window 3: Magnitude absolute (Capture buffer)
Window 4: Symbol table (hexadecimal)
= Sample rate (4)
Apart from the "Preset Channel" function (see
"Preset Channel" on page 133), the fol-
lowing functions are available to restore factory settings to the VSA application (via softkeys in the MEAS menu):
Restore Factory Settings
Opens a submenu that allows you to restore all standards and pattern settings on the instrument to the values predefined by Rohde & Schwarz available at the time of delivery.
Restore Standard Files ← Restore Factory Settings
Restores the standards predefined by Rohde & Schwarz available at the time of delivery.
Note that this function will overwrite customized standards that have the same name as predefined standards.
Remote command:
[SENSe:]DDEMod:FACTory[:VALue] on page 273
Restore Pattern Files ← Restore Factory Settings
Restores the pattern files predefined by Rohde&Schwarz available at the time of delivery.
Remote command:
[SENSe:]DDEMod:FACTory[:VALue] on page 273
5.2 Configuration According to Digital Standards
Various predefined settings files for common digital standards are provided for use with the VSA application. In addition, you can create your own settings files for user-specific measurements.
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Configuration According to Digital Standards
For an overview of predefined standards and settings see chapter A.2, "Predefined
Digital standard settings are available via the "Digital Standards" button in the "Overview" or the"Digital Standards" softkey in the MEAS menu.
└ Selecting the Storage Location - Drive/ Path/ Files ...................................... 130
Digital Standards
Opens a file selection dialog to manage predefined measurement settings for conventional mobile radio standards.
Selecting the Storage Location - Drive/ Path/ Files ← Digital Standards
Select the storage location of the settings file on the instrument or an external drive.
The "Drive" indicates the internal (C:) or any connected external drives (e.g. a USB storage device).
The "Path" contains the drive and the complete file path to the currently selected folder.
The "Files" list contains all subfolders and files of the currently selected path.
The default storage location for the standards files is:
C:\R_S\Instr\user\vsa\Standards.
Note: Saving instrument settings in secure user mode.
In secure user mode all data is stored to volatile memory, and is only available during the current instrument session. As soon as the power is switched off on the R&S FPS, the data is cleared.
To store settings 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 User Manual.
New Folder ← Digital Standards
Creates a new folder in the file system in which you can save the settings file.
File Name ← Digital Standards
Contains the name of the data file without the path or extension.
By default, the name of a settings file consists of a base name followed by an underscore. Multiple files with the same base name are extended by three numbers, e.g.
limit_lines_005.
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Configuration According to Digital Standards
For details on the file name and location see the "Data Management" topic in the
R&S FPS User Manual.
Note: Secure user mode. In secure user mode, settings that are to be stored on the instrument are stored to volatile memory. 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 User Manual.
Comment ← Digital Standards
An optional description for the data file. A maximum of 60 characters can be displayed.
Remote command:
[SENSe:]DDEMod:STANdard:COMMent on page 274
Load Standard ← Digital Standards
Loads the selected measurement settings file.
Note: When you load a standard, the usage of a known data file, if available, is automatically deactivated.
Remote command:
[SENSe:]DDEMod:PRESet[:STANdard] on page 274
Save Standard ← Digital Standards
Saves the current measurement settings for a specific standard as a file with the defined name.
Remote command:
[SENSe:]DDEMod:STANdard:SAVE on page 275
Delete Standard ← Digital Standards
Deletes the selected standard. Standards predefined by Rohde & Schwarz can also be deleted. A confirmation query is displayed to avoid unintentional deletion of the standard.
Note: Restoring predefined standard files. The standards predefined by Rohde &
Schwarz available at the time of delivery can be restored using the "Restore Standards" function (see
"Restore Standard Files" on page 129).
Remote command:
[SENSe:]DDEMod:STANdard:DELete on page 274
Restore Standard Files ← Digital Standards
Restores the standards predefined by Rohde & Schwarz available at the time of delivery.
Note that this function will overwrite customized standards that have the same name as predefined standards.
Remote command:
[SENSe:]DDEMod:FACTory[:VALue] on page 273
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Configuration Overview
5.3 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".
In particular, the "Overview" provides quick access to the following configuration dialog boxes (listed in the recommended order of processing):
1. Signal Description
See chapter 5.4, "Signal Description" , on page 134
2. Input and Frontend Settings
See chapter 5.5, "Input, Output and Frontend Settings" , on page 142
3. Signal Capture (including Triggering)
See chapter 5.6, "Signal Capture" , on page 154
4. Burst/Pattern Configuration
See chapter 5.7, "Burst and Pattern Configuration" , on page 164
5. Result Range Definition
See chapter 5.8, "Result Range Configuration" , on page 173
6. Demodulation Settings
See chapter 5.9, "Demodulation Settings" , on page 175
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Configuration Overview
7. Measurement Filter Settings
See chapter 5.10, "Measurement Filter Settings" , on page 185
8. Evaluation Range Definition
See chapter 5.11, "Evaluation Range Configuration" , on page 187
9. Display Configuration
The "Display Config" button is only available in the general overview, not in the window-specific overview (see
See chapter 6.5, "Display and Window Configuration" , on page 201
10. Analysis
See chapter 6, "Analysis" , on page 190
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.
For step-by-step instructions on configuring VSA measurements, see
chapter 8, "How to Perform Vector Signal Analysis" , on page 210.
Preset Channel
Select the "Preset Channel" button in the lower lefthand corner of the "Overview" to restore all measurement settings in the current channel to their default values.
Note that the PRESET key restores the entire instrument to its default values and thus closes all measurement channels on the R&S FPS (except for the default Spectrum application channel)!
See
chapter 5.1, "Default Settings for Vector Signal Analysis" , on page 128 for details.
Remote command:
SYSTem:PRESet:CHANnel[:EXECute] on page 273
Specifics for
The measurement 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 "Specifics for" selection list that is displayed in the
"Overview" and in all window-specific configuration dialog boxes.
Enable the "Specifics for" option.
The "Overview" and dialog boxes are updated to indicate the settings for the selected window.
The indicated data flow is updated for the selected data source.
If the "Specifics for" option is not enabled, the overview displays the default data flow and the general settings independently of the selected window.
Note: The "Display Config" button is only available in the general overview, not in the window-specific overview.
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Signal Description
Digital Standards
Opens a file selection dialog to manage predefined measurement settings for conven-
tional mobile radio standards. See chapter 5.2, "Configuration According to Digital
5.4 Signal Description
The signal description provides information on the expected input signal, which optimizes burst and pattern detection and allows for the application to calculate an ideal reference signal. The signal description consists of information on the used modulation and on the signal's structure.
5.4.1 Modulation
The "Modulation" settings contain modulation and transmit filter settings. A live preview of the Constellation I/Q trace using the currently defined settings is displayed at the bottom of the dialog box to visualize the changes to the settings. The preview area is not editable directly.
The modulation settings vary depending on the selected modulation type; in particular,
FSK modulation provides some additional settings.
The "Modulation" settings are displayed when you do one of the following:
● Select the "Signal Description" button in the "Overview".
● Select the "Signal Description" softkey in the main VSA menu.
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Signal Description
Fig. 5-1: Signal modulation settings for FSK modulation
Modulation Type
Defines the modulation type of the vector signal. The following types are available:
● PSK
● MSK
● QAM
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Signal Description
● FSK
● ASK
● APSK
● User Modulation
Uses the selected user-defined modulation loaded from a file.
For more information on these modulation types see chapter 4.3, "Symbol Mapping" , on page 67.
Remote command:
[SENSe:]DDEMod:FORMat on page 278
Load User Modulation ← Modulation Type
This function is only available if the modulation type "User Modulation" is selected.
Opens a file selection dialog box to select the file that contains the user-defined modulation (*.vam file).
Remote command:
SENS:DDEM:FORM UQAM (see
[SENSe:]DDEMod:FORMat on page 278)
[SENSe:]DDEMod:USER:NAME on page 284
Modulation Order
Depending on the
Modulation Type , various orders of modulation are available:
Type
PSK
MSK
QAM
FSK
Available orders
BPSK
QPSK
Offset QPSK
Pi/4-QPSK
MSK
16QAM
Pi/4-16QAM
32QAM
2FSK
3Pi/4-QPSK
8PSK
3Pi/8-8PSK
D8PSK
DMSK
-Pi/4-32QAM
64QAM
128QAM
4FSK
Pi/8-D8PSK
DQPSK
Pi/4-DQPSK
256QAM
512QAM
1024QAM
8FSK
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Signal Description
Type
ASK
APSK
Available orders
2ASK
16APSK
4ASK
32APSK
Remote command:
PSK:
[SENSe:]DDEMod:PSK:FORMat on page 280
[SENSe:]DDEMod:PSK:NSTate on page 281
[SENSe:]DDEMod:QPSK:FORMat on page 282
MSK:
[SENSe:]DDEMod:MSK:FORMat on page 280
QAM:
[SENSe:]DDEMod:QAM:FORMat on page 281
[SENSe:]DDEMod:QAM:NSTate on page 281
FSK: [SENSe:]DDEMod:FSK:NSTate on page 279
ASK:
[SENSe:]DDEMod:ASK:NSTate on page 277
APSK:
[SENSe:]DDEMod:APSK:NSTate on page 277
FSK Ref Deviation (FSK only)
The FSK Reference Deviation sets the deviation to the reference frequency.
In case of 2FSK, it indicates the distance from the reference frequency to the positive / negative deviation frequency and in case of 4FSK, the distance to the outer positive/ negative deviation frequency.
To set the deviation as a multiple of the symbol rate (x*SR), select "Relative" mode. To set the deviation as an absolute value in Hz, select "Absolute" mode.
Note that this parameter is available only for FSK modulated signals.
Remote command:
CALCulate<n>:FSK:DEViation:REFerence[:VALue] on page 277
CALCulate<n>:FSK:DEViation:REFerence:RELative on page 276
Modulation Mapping
The available mapping types depend on the Modulation Type
and
.
For more information on the modulation mapping, refer to chapter 4.3, "Symbol Mapping" , on page 67
Remote command:
[SENSe:]DDEMod:MAPPing[:VALue] on page 279
[SENSe:]DDEMod:MAPPing:CATalog?
Symbol Rate
The symbol rate also determines the I/Q bandwidth of the data recording and demodulation. You can change the default rate by entering a value in Hz.
The minimum symbol rate is 25 Hz. The maximum symbol rate depends on the defined
chapter 4.2, "Sample Rate, Symbol Rate and I/Q Bandwidth" , on page 63).
Remote command:
[SENSe:]DDEMod:SRATe on page 282
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Signal Description
Transmit Filter Type
Defines the type of transmit filter
Remote command:
[SENSe:]DDEMod:TFILter:NAME on page 283
To define the name of the transmit filter to be used.
[SENSe:]DDEMod:TFILter[:STATe] on page 283
To switch off the transmit filter.
[SENSe:]DDEMod:TFILter:USER on page 284
To select a user-defined filter.
Load User Filter ← Transmit Filter Type
Opens a file-selection dialog box to select the user-defined transmit filter to be used.
Note: If a user-defined transmit filter is selected and the measurement filter is defined
culated and used.
For details see
chapter 4.1.5, "Customized Filters" , on page 61.
For detailed instructions on working with user-defined filters see
Select User-Defined Filters" , on page 213.
Remote command:
[SENSe:]DDEMod:TFILter:USER on page 284
[SENSe:]DDEMod:TFILter:NAME on page 283
Alpha/BT
Defines the roll-off factor (Alpha) or the filter bandwidth (BT).
The roll-off factor and filter bandwidth for transmit filter is available for RC, RRC, Gauss and GMSK filter.
Remote command:
[SENSe:]DDEMod:TFILter:ALPHa on page 283
5.4.2 Signal Structure
The "Signal Structure" settings describe the expected input signal and determine which settings are available for configuration. You can define a pattern to which the instrument can be synchronized, thus adapting the result range.
A visualization of the currently defined signal structure is displayed at the bottom of the dialog box.
The "Signal Structure" settings are displayed when you do one of the following:
● Select the "Signal Description" button in the "Overview".
● Select the "Signal Description" softkey in the main VSA menu.
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Then switch to the "Signal Structure" tab.
Configuration
Signal Description
Signal Type
Determines whether the signal is continuous or contains bursts.
Remote command:
[SENSe:]DDEMod:SIGNal[:VALue] on page 286
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Signal Description
Burst Settings
For bursts, further settings are available.
Min Length / Max Length ← Burst Settings
Shortest and longest expected burst length in symbols ( ≦32000). The symbols are converted to seconds for reference.
Remote command:
[SENSe:]DDEMod:SEARch:BURSt:LENGth:MAXimum on page 285
[SENSe:]DDEMod:SEARch:BURSt:LENGth[:MINimum] on page 285
Run-In ← Burst Settings
The number of symbols before the signal is assumed to have valid modulated symbols.
The symbols are converted to seconds for reference.
Remote command:
[SENSe:]DDEMod:SEARch:BURSt:SKIP:RISing on page 286
Run-Out ← Burst Settings
The number of symbols before the falling edge that do not necessarily need to have a valid modulation.
The symbols are converted to seconds for reference.
Remote command:
[SENSe:]DDEMod:SEARch:BURSt:SKIP:FALLing on page 285
Pattern Settings
If the signal is expected to have a specific pattern, enable the "Pattern" option to define the pattern settings.
Note: The pattern search itself must be enabled separately in the "Pattern Search Settings", see
"Enabling Pattern Searches" on page 167. By default, the pattern search is
active if the signal description contains a pattern.
Name ← Pattern Settings
Specifies the pattern name from the list of defined patterns. You can also configure new patterns, see
chapter 5.7.3, "Pattern Configuration" , on page 168.
Remote command:
[SENSe:]DDEMod:SIGNal:PATTern on page 286
Pattern Configuration ← Pattern Settings
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Signal Description
Offset ← Pattern Settings
The offset of the pattern is defined with respect to the start of the useful part of the burst (see
"Useful length" on page 119). If the position of the pattern within the burst is
known, it is recommended that you define the offset. That will accelerate the pattern search and enhance the accuracy of the burst search.
Remote command:
[SENSe:]DDEMod:STANdard:SYNC:OFFSet:STATe on page 287
[SENSe:]DDEMod:STANdard:SYNC:OFFSet[:VALue] on page 287
5.4.3 Known Data
The "Known Data" settings allow you to load a file that describes the possible data sequences in the input signal.
(See
chapter 8.2.3, "How to Manage Known Data Files" , on page 218).
Additional information provided by the loaded file is displayed at the bottom of the dialog box. This information is not editable directly.
The "Known Data" settings are displayed when you do one of the following:
● Select the "Signal Description" button in the "Overview".
● Select the "Signal Description" softkey in the main VSA menu.
Then switch to the "Known Data" tab.
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Auxiliary tool to create Known Data files
An auxiliary tool to create Known Data files from data that is already available in the
VSA application is provided on the instrument free of charge.
See
"To create a Known Data file using the recording tool for sequences" on page 219.
Known Data
Activates or deactivates the use of the loaded data file (if available). When deactivated, the additional information from the previously loaded data file is removed. Any references to the known data in the "Demodulation" dialog box are replaced by the default parameter values (see
chapter 5.9.2, "Advanced Demodulation (Synchronization)" , on page 180).
Note: When a standard is loaded, the use of a Known Data file is automatically deactivated.
Remote command:
[SENSe:]DDEMod:KDATa:STATe on page 323
Load Data File
If
is activated, this function displays a file selection dialog box to select the xml file that contains the known data. Once a file has been selected, any additional information provided by the file is displayed at the bottom of the dialog box.
Remote command:
[SENSe:]DDEMod:KDATa[:NAME] on page 324
5.5 Input, Output and Frontend Settings
The R&S FPS can evaluate signals from different input sources.
The frequency and amplitude settings represent the "frontend" of the measurement setup.
5.5.1 Input Settings
Input settings can be configured via the INPUT/OUTPUT key, in the "Input" dialog box.
Some settings are also available in the "Amplitude" tab of the "Amplitude" dialog box.
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5.5.1.1
Radio Frequency Input
The default input source for the R&S FPS is the radio frequency. If no additional options are installed, this is the only available input source.
Radio Frequency State
Activates input from the RF INPUT connector.
Remote command:
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:
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.
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If option R&S FPS-B24 is installed, the preamplifier is active for all frequencies.
Remote command:
5.5.2 Output Settings
The R&S FPS VSA application can provide trigger output to other devices.
For details on connectors refer to the R&S FPS Getting Started manual, "Front / Rear
Panel View" chapters.
Output settings can be configured via the INPUT/OUTPUT key or in the "Outputs" dialog box.
IF/VIDEO Output
Defines the type of signal available at the IF/VIDEO on the rear panel of the R&S FPS.
For restrictions and additional information see the R&S FPS I/Q Analyzer and I/Q Input
User Manual.
"IF"
"VIDEO"
The measured IF value is available at the IF/VIDEO output connector.
The displayed video signal (i.e. the filtered and detected IF signal) is available at the IF/VIDEO output connector.
This setting is required to provide demodulated audio frequencies at the output.
Remote command:
OUTPut:IF[:SOURce] on page 289
Trigger 2
Defines the usage of the variable TRIGGER AUX connector on the rear panel.
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(Trigger 1 is INPUT only.)
Note: Providing trigger signals as output is described in detail in the R&S FPS User
Manual.
"Input"
"Output"
The signal at the connector is used as an external trigger source by the R&S FPS. No further trigger parameters are available for the connector.
The R&S FPS sends a trigger signal to the output connector to be used by connected devices.
Further trigger parameters are available for the connector.
Remote command:
OUTPut:TRIGger<port>:LEVel on page 289
OUTPut:TRIGger<port>:DIRection on page 289
Output Type ← Trigger 2
Type of signal to be sent to the output
"Device Triggered"
(Default) Sends a trigger when the R&S FPS triggers.
"Trigger
Armed"
Sends a (high level) trigger when the R&S FPS is in "Ready for trigger" state.
This state is indicated by a status bit in the STATus:OPERation register (bit 5).
"User Defined" Sends a trigger when user selects "Send Trigger" button.
In this case, further parameters are available for the output signal.
Remote command:
OUTPut:TRIGger<port>:OTYPe on page 290
Level ← Output Type ← Trigger 2
Defines whether a constant high (1) or low (0) signal is sent to the output connector.
Remote command:
OUTPut:TRIGger<port>:LEVel on page 289
Pulse Length ← Output Type ← Trigger 2
Defines the length of the pulse sent as a trigger to the output connector.
Remote command:
OUTPut:TRIGger<port>:PULSe:LENGth on page 290
Send Trigger ← Output Type ← Trigger 2
Sends a user-defined trigger to the output connector immediately. Note that the trigger pulse level is always opposite to the constant signal level defined by the output "Level" setting, e.g. for "Level = High", a constant high signal is output to the connector until the "Send Trigger" button is selected. Then, a low pulse is sent.
Which pulse level will be sent is indicated by a graphic on the button.
Remote command:
OUTPut:TRIGger<port>:PULSe:IMMediate on page 290
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5.5.3 Frequency Settings
Frequency settings for the input signal can be configured via the "Frequency" dialog box, which is displayed when you do one of the following:
● Select the FREQ key and then the "Frequency Config" softkey.
● Select the "Frequency" tab in the "Input Settings" dialog box.
Center frequency
Defines the normal center frequency of the signal.
The allowed range of values for the center frequency depends on the frequency span.
span > 0: span min
/2 ≤ f center
≤ f max
– span min
/2 f max
and span min
depend on the instrument and are specified in the data sheet.
Remote command:
[SENSe:]FREQuency:CENTer on page 291
Center Frequency Stepsize
Defines the step size of the center frequency. The step size can be set to a predefined value, or it can be manually set to a user-defined value.
"Auto" The step size is set to the default value:
● using the rotary knob: 100 kHz
● using the arrow keys: 1 MHz
"Manual" Defines a user-defined step size for the center frequency. Enter the step size in the "Value" field.
Remote command:
[SENSe:]FREQuency:CENTer:STEP:AUTO on page 292
[SENSe:]FREQuency:CENTer:STEP on page 291
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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, but not if it shows frequencies relative to the signal's center frequency.
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 -100 GHz to 100 GHz. The default setting is 0 Hz.
Note: In MSRA mode, this function is only available for the MSRA Master.
Remote command:
[SENSe:]FREQuency:OFFSet on page 292
5.5.4 Amplitude and Vertical Axis Configuration
Amplitude and scaling settings allow you to configure the vertical (y-)axis display and for some result displays also the horizontal (x-)axis.
5.5.4.1
Amplitude Settings
Amplitude settings affect the signal power or error levels.
To configure the amplitude settings select the AMPT key and then the "Amplitude Config" softkey.
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Note that amplitude settings are not window-specific, as opposed to the scaling and unit settings.
└ Setting the Reference Level Automatically (Auto Level) ...............................148
Reference Level
Defines the expected maximum reference level. Signal levels above this value may not be measured correctly, which is indicated by the "IF OVLD" status display ("OVLD" for digitial baseband input).
The reference level is also 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 to ensure an optimum measurement (no compression, good signal-to-noise ratio).
Remote command:
DISPlay[:WINDow<n>]:TRACe<t>:Y[:SCALe]:RLEVel on page 293
Shifting the Display (Offset) ← Reference Level
Defines an arithmetic level offset. This offset is added to the measured level. 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 will be shifted by this value.
The setting range is ±200 dB in 0.01 dB steps.
Note, however, that the internal reference level (used to adjust the hardware settings to the expected signal optimally) ignores any "Reference Level Offset". Thus, it is important to keep in mind the actual power level the R&S FPS must handle, and not to 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 293
Setting the Reference Level Automatically (Auto Level) ← Reference Level
Automatically determines the optimal reference level for the current input data. At the same time, the internal attenuators are adjusted so the signal-to-noise ratio is optimized, while signal compression, clipping and overload conditions are minimized.
To determine the optimal reference level, a level measurement is performed on the
R&S FPS.
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You can change the measurement time for the level measurement if necessary (see
"Changing the Automatic Measurement Time (Meastime Manual)" on page 189).
Remote command:
[SENSe:]ADJust:LEVel on page 332
Input Settings
Some input settings affect the measured amplitude of the signal, as well.
For information on other input settings see chapter 5.5.1, "Input Settings" , on page 142.
Preamplifier (option B22/B24) ← Input Settings
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 Coupling ← Input Settings
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:
RF Attenuation
Defines the mechanical attenuation for RF input.
Attenuation Mode / Value ← RF Attenuation
The RF attenuation can be set automatically as a function of the selected reference level (Auto mode). This ensures that the optimum RF attenuation is always used. It is the default setting.
By default and when Using Electronic Attenuation is not available, mechanical attenua-
tion 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.
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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:ATTenuation:AUTO on page 295
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) >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 may be set to automatic mode, and the full attenuation is provided by the mechanical attenuator, if possible.
Both the electronic and the mechanical attenuation can be varied in 1 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:
5.5.4.2
Scaling
Depending on the type of display (time, spectrum or statistics), various scaling functions are available to adapt the result display to the current data.
Note that scaling settings are window-specific, as opposed to the amplitude settings.
The scaling settings are displayed when you select the AMPT key and then the "Scale
Config" softkey.
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Fig. 5-2: Scaling settings for statistical evaluation
For details on the different methods to configure the scaling see
Change the Display Scaling" , on page 223.
A visualization of the diagram scaling with the current settings is displayed at the right side of the dialog box.
Auto Scale Once/Auto Scale Window
If enabled, both the x-axis and y-axis are automatically adapted to the current measurement results (only once, not dynamically) in the selected window.
To adapt the range of all screens together, use the Auto Scale All function.
Remote command:
DISPlay[:WINDow<n>]:TRACe<t>:Y[:SCALe]:AUTO ONCE on page 330
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Defining Min and Max Values
Indicates the current range borders according to the current settings (for information only).
For statistical evaluations only: defines the displayed range using minimum and maximum values.
Values in the range 1e -9 < value < 0.1 are allowed. The y-axis unit is defined via the
Axis Unit" on page 154 setting. The distance between max and min value must be at
least one decade.
Remote command:
CALCulate<n>:STATistics:SCALe:Y:UPPer on page 297
CALCulate<n>:STATistics:SCALe:Y:LOWer on page 297
Configuring a Reference Point and Divisions
Defines the displayed range using a reference point and the size of the divisions.
Y-Axis Reference Value ← Configuring a Reference Point and Divisions
Defines a reference value on the y-axis in the current unit. The y-axis is adapted so
that the reference value is displayed at the "Y-Axis Reference Position" on page 152.
Remote command:
DISPlay[:WINDow<n>]:TRACe<t>:Y[:SCALe]:RVALue on page 300
Y-Axis Reference Position ← Configuring a Reference Point and Divisions
Defines the position of the
Y-Axis Reference Value on the y-axis. The position is
defined as a percentage value, where 0 % refers to the bottom edge, 100 % refers to the top edge of the screen. The y-axis is adapted so that the reference value is displayed at the reference position.
Remote command:
DISPlay[:WINDow<n>]:TRACe<t>:Y[:SCALe]:RPOSition on page 300
Range per Division ← Configuring a Reference Point and Divisions
Defines the value range to be displayed per division. Since the display consists of 10 divisions by default, the displayed range is:
Range = 10 * <Range per Division>
Note: If fewer divisions are displayed (e.g. because the window is reduced in height), the range per division is increased in order to display the same result range in the smaller window. In this case, the per division value does not correspond to the actual display.
Remote command:
DISPlay[:WINDow<n>]:TRACe<t>:Y[:SCALe]:PDIVision on page 299
X-Axis Scaling
For statistics, a histogram is displayed. For these diagrams, the x-axis can be configured, as well.
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Adjust Settings ← X-Axis Scaling
Adjusts the x-axis scaling to the occurring statistical values.
Remote command:
CALCulate<n>:STATistics:SCALe:AUTO ONCE on page 297
Default Settings ← X-Axis Scaling
Resets the x- and y-axis scalings to their preset values for the current measurement window.
Remote command:
CALCulate<n>:STATistics:PRESet on page 296
Quantize ← X-Axis Scaling
Defines the number of bars to be displayed in the graph, i.e. the granularity of classifications.
Remote command:
CALCulate<n>:STATistics:SCALe:X:BCOunt on page 297
X-Axis Reference Value ← X-Axis Scaling
Defines a reference value on the x-axis in the current unit.
Remote command:
DISPlay[:WINDow<n>]:TRACe<t>:X[:SCALe]:RVALue on page 299
X-Axis Reference Position ← X-Axis Scaling
Defines the position of the
X-Axis Reference Value on the x-axis. The position is
defined as a percentage value, where 0 % refers to the beginning (left side), 100 % refers to the end (right side) of the diagram. The x-axis is adapted so that the reference value is displayed at the reference position.
Remote command:
DISPlay[:WINDow<n>]:TRACe<t>:X[:SCALe]:RPOSition on page 299
Range per Division ← X-Axis Scaling
Defines the value range to be displayed per division on the x-axis. Since the display consists of 10 divisions by default, the displayed range is:
Range = 10 * <Range per Division>
Note: If fewer divisions are displayed (e.g. because the window is reduced in width), the range per division is increased in order to display the same result range in the smaller window. In this case, the per division value does not correspond to the actual display.
Remote command:
DISPlay[:WINDow<n>]:TRACe<t>:X[:SCALe]:PDIVision on page 299
5.5.4.3
Units
You can configure the units for both axes of the diagrams.
The unit settings are displayed when you do one of the following:
● Select "Input/Frontend" from the "Overview" and then switch to the "Unit" tab.
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● Select the AMPT key and then the "Unit Config" softkey.
Configuration
Signal Capture
Note that unit settings are window-specific, as opposed to the amplitude settings.
X-Axis Unit
Defines the unit of the x-axis in the current result diagram.
Remote command:
CALCulate<n>:X:UNIT:TIME on page 298
Y-Axis Unit
Defines the unit of the y-axis in the current result diagram.
Remote command:
DISPlay[:WINDow<n>]:TRACe<t>:Y:SPACing on page 300
For phase diagrams:
CALCulate<n>:UNIT:ANGLe on page 298
For statistics:
CALCulate<n>:STATistics:SCALe:Y:UNIT on page 298
For equalizer group delay diagrams: CALCulate<n>:Y:UNIT:TIME on page 298
5.6 Signal Capture
The "Signal Capture" settings define how much, how and when data is captured from the input signal.
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Signal Capture
The "Signal Capture" settings are displayed when you do one of the following:
● Select the "Signal Capture" button from the "Overview".
● Select the "Signal Capture" softkey from the main VSA menu.
5.6.1 Data Acquisition
The "Data Acquisition" settings define how much and how data is captured from the input signal.
A live preview of the signal in the capture buffer with the current settings is displayed in the preview area at the bottom of the dialog box. The preview area is not editable directly.
The "Data Acquisition" settings are displayed when you do one of the following:
● Select the "Signal Capture" button from the "Overview".
● Select the "Signal Capture" softkey from the main VSA menu.
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Signal Capture
MSRA operating mode
In MSRA operating mode, only the MSRA Master channel actually captures data from the input signal. The data acquisition settings for the VSA application in MSRA mode define the application data extract and analysis interval.
For details on the MSRA operating mode see the R&S FPS MSRA User Manual.
Capture Length Settings
The capture length defines how many symbols are captured during each measurement.
Enable the "Auto" option to define the capture length automatically according to the burst and pattern length settings and the statistics count. Thus, a minimal capture length is used, which improves performance.
If the capture length is not defined automatically, enter the number of symbols or seconds to be captured and select the used unit. The defined number is converted to the alternative unit (seconds/symbols) for reference.
As of firmware version 1.70, up to 64000 symbols can be captured and processed during each measurement (previously 50000).
Remote command:
[SENSe:]DDEMod:RLENgth:AUTO on page 302
[SENSe:]DDEMod:RLENgth[:VALue] on page 302
Sample Rate
Defines the number of samples to capture per symbol. The sample rate in MHz is indicated for reference. This parameter affects the demodulation bandwidth and thus the usable I/Q bandwidth.
The maximum sample rate depends on the defined
"Sample Rate, Symbol Rate and I/Q Bandwidth" , on page 63).
Remote command:
[SENSe:]DDEMod:PRATe on page 301
Usable I/Q Bandwidth
Shows the usable I/Q bandwidth which depends on the selected sample rate. For details see
chapter 4.2, "Sample Rate, Symbol Rate and I/Q Bandwidth" , on page 63.
This information is provided for reference only.
Note:
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Signal Capture
In diagrams in the frequency domain (Spectrum transformation, see
Transformation" on page 202) the usable I/Q bandwidth is indicated by vertical blue
lines.
Remote command:
Swap I/Q
Activates or deactivates the inverted I/Q modulation. If the I and Q parts of the signal from the DUT are interchanged, the R&S FPS can do the same to compensate for it.
On
Off
I and Q signals are interchanged
Inverted sideband, Q+j*I
I and Q signals are not interchanged
Normal sideband, I+j*Q
Remote command:
5.6.2 Trigger Settings
The trigger settings define the beginning of a measurement.
The "Trigger" settings are displayed when you do one of the following:
● Select the "Signal Capture" button from the "Overview".
● Select the "Signal Capture" softkey from the main VSA menu.
Then switch to the "Trigger" tab.
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Signal Capture
The TRIGGER INPUT/OUTPUT connectors on the R&S FPS can only be used for input in the VSA application, for use as external triggers. No configuration settings are available for trigger input.
For step-by-step instructions on configuring triggered measurements, see the
R&S FPS User Manual.
MSRA operating mode
In MSRA operating mode, only the MSRA Master channel actually captures data from the input signal. Thus, no trigger settings are available in the VSA application in MSRA operating mode. However, a capture offset can be defined with a similar effect as a trigger offset. It defines an offset from the start of the captured data (from the MSRA
Master) to the start of the application data for vector signal analysis. (See
.)
For details on the MSRA operating mode see the R&S FPS MSRA User Manual.
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Trigger Source
Defines the trigger source. If a trigger source other than "Free Run" is set, "TRG" is displayed in the channel bar and the trigger source is indicated.
Remote command:
TRIGger[:SEQuence]:SOURce on page 306
Free Run ← Trigger Source
No trigger source is considered. Data acquisition is started manually or automatically and continues until stopped explicitely.
Remote command:
TRIG:SOUR IMM, see
TRIGger[:SEQuence]:SOURce on page 306
External Trigger 1/2 ← Trigger Source
Data acquisition starts when the TTL signal fed into the specified input connector meets or exceeds the specified trigger level.
(See
Note: The "External Trigger 1" softkey automatically selects the trigger signal from the
TRG IN connector.
For details see the "Instrument Tour" chapter in the R&S FPS Getting Started manual.
"External Trigger 1"
Trigger signal from the TRG IN connector.
"External Trigger 2"
Trigger signal from the TRG AUX connector.
Remote command:
TRIG:SOUR EXT, TRIG:SOUR EXT2
See
TRIGger[:SEQuence]:SOURce on page 306
IF Power ← Trigger Source
The R&S FPS starts capturing data as soon as the trigger level is exceeded around the third intermediate frequency.
For frequency sweeps, the third IF represents the start frequency. The trigger bandwidth at the third IF depends on the RBW and sweep type.
For measurements on a fixed frequency (e.g. zero span or I/Q measurements), the third IF represents the center frequency.
This trigger source is only available for RF input.
The available trigger levels depend on the RF attenuation and preamplification. A reference level offset, if defined, is also considered.
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Signal Capture
For details on available trigger levels and trigger bandwidths see the data sheet.
Remote command:
TRIG:SOUR IFP, see
TRIGger[:SEQuence]:SOURce on page 306
I/Q Power ← Trigger Source
Triggers the measurement when the magnitude of the sampled I/Q data exceeds the trigger threshold.
The trigger bandwidth corresponds to the "Usable I/Q Bandwidth" setting for data
acquisition (see "Usable I/Q Bandwidth" on page 156).
Remote command:
TRIG:SOUR IQP, see
TRIGger[:SEQuence]:SOURce on page 306
Trigger Level
Defines the trigger level for the specified trigger source.
For details on supported trigger levels, see the data sheet.
Remote command:
TRIGger[:SEQuence]:LEVel:IFPower on page 305
TRIGger[:SEQuence]:LEVel:IQPower on page 305
TRIGger[:SEQuence]:LEVel[:EXTernal<port>] on page 305
Trigger Offset
Defines the time offset between the trigger event and the start of the measurement.
The time may be entered in s or in symbols.
offset > 0: offset < 0:
Start of the measurement is delayed
Measurement starts earlier (pre-trigger)
Only possible for zero span (e.g. I/Q Analyzer application) and gated trigger switched off
Maximum allowed range limited by the measurement time: pretrigger max
= measurement time max
Remote command:
TRIGger[:SEQuence]:HOLDoff[:TIME] on page 304
Hysteresis
Defines the distance in dB to the trigger level that the trigger source must exceed before a trigger event occurs. Settting a hysteresis avoids unwanted trigger events caused by noise oscillation around the trigger level.
This setting is only available for "IF Power" trigger sources. The range of the value is between 3 dB and 50 dB with a step width of 1 dB.
Remote command:
TRIGger[:SEQuence]:IFPower:HYSTeresis on page 304
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Signal Capture
Drop-Out Time
Defines the time the input signal must stay below the trigger level before triggering again.
Remote command:
TRIGger[:SEQuence]:DTIMe on page 304
Slope
For all trigger sources except time you can define whether triggering occurs when the signal rises to the trigger level or falls down to it.
Remote command:
TRIGger[:SEQuence]:SLOPe on page 306
Trigger Holdoff
Defines the minimum time (in seconds) that must pass between two trigger events.
Trigger events that occur during the holdoff time are ignored.
Remote command:
TRIGger[:SEQuence]:IFPower:HOLDoff on page 304
Capture Offset
This setting is only available for applications in MSRA operating mode. It has a similar effect as the trigger offset in other measurements: it defines the time offset between the capture buffer start and the start of the extracted application data.
In MSRA mode, the offset must be a positive value, as the capture buffer starts at the trigger time = 0.
Remote command:
[SENSe:]MSRA:CAPTure:OFFSet on page 355
5.6.3 Sweep Settings
The sweep settings define how often data from the input signal is acquired and then evaluated. They are configured via the SWEEP key.
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.
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Signal Capture
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 has an 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.
For details on the Sequencer, see the R&S FPS User Manual.
Remote command:
INITiate<n>:CONTinuous on page 333
Single Sweep/ RUN SINGLE
After triggering, starts the number of evaluations set in "Statistics Count". The measurement stops after the defined number of evaluations 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 334
Continue Single Sweep
After triggering, repeats the number of evaluations set in "Statistics Count", without deleting the trace of the last measurement.
While the measurement is running, the "Continue Single Sweep" softkey and the RUN
SINGLE key are highlighted. The running measurement can be aborted by selecting the highlighted softkey or key again.
Remote command:
INITiate<n>:CONMeas on page 333
Refresh (non-Multistandard mode)
Repeats the evaluation of the data currently in the capture buffer without capturing new data. This is useful after changing settings, for example filters, patterns or evaluation ranges.
Remote command:
Statistic Count
Defines the number of measurements to be considered for statistical evaluations. The behavior depends on the active sweep mode.
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Signal Capture
Activate "Description" to display a visualization of the behavior of the current settings.
Note: If the "Statistic Count" is set to 1, trace averaging is not performed; Max Hold and Min Hold, however, remain active, unlike in the Spectrum application.
"Auto" In single sweep mode: captures the I/Q data once and evaluates it
In continuous sweep mode: captures I/Q data continuously; for each evaluation, the average is calculated over the last 10 capture sets
(moving average)
"Manual" In single sweep mode: captures I/Q data until the defined number of evaluations have been performed
In continuous sweep mode: captures I/Q data continuously; if trace averaging is selected, the average is calculated over the defined number of capture sets (moving average);
Remote command:
[SENSe:]SWEep:COUNt[:VALue] on page 307
Select Result Rng
Selects the result range from the capture buffer that you want to evaluate.
This function is available in single sweep mode only.
By default, the application shows the results over all result ranges that have been captured in the signal capturing process and are in the R&S FPS's memory. By selecting a range number, you can evaluate a specific result range, e.g. a particular burst.
The range depends on the number of result ranges you have captured previously.
For more information refer also to
chapter 4.6, "Measurement Ranges" , on page 116.
Remote command:
[SENSe:]DDEMod:SEARch:MBURst:CALC on page 307
Refresh
This function is only available if the Sequencer is deactivated and only for MSRA
applications.
The data in the capture buffer is re-evaluated by the currently active application only.
The results for any other applications remain unchanged.
This is useful, for example, after evaluation changes have been made or if a new sweep was performed from another application; in this case, only that application is updated automatically after data acquisition.
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Burst and Pattern Configuration
Note: To update all active applications at once, use the "Refresh all" function in the
"Sequencer" menu.
Remote command:
INITiate<n>:REFResh on page 335
5.7 Burst and Pattern Configuration
Information on known patterns and bursts in the captured signal improve the accuracy of the determined ideal reference signal, and calculation of the signal parameters becomes quicker.
For details on burst and patterns see
chapter 4.4, "Overview of the Demodulation Process" , on page 88.
5.7.1 Burst Search
The "Burst Search" settings define when a burst is detected in the evaluated signal.
A live preview of the capture buffer with the current settings is displayed in the preview area at the bottom of the dialog box. The blue lines below the trace indicate the detected bursts. The preview area is not editable directly.
The "Burst Search" settings are displayed when you do one of the following:
● Select the "Burst/Pattern" button from the "Overview".
● Select the "Burst/Pattern Search" softkey from the main VSA menu.
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Burst and Pattern Configuration
Enabling Burst Searches
Enables or disables burst searches. If "Auto" is selected, burst search is enabled only if the signal structure defines a bursted signal (in the "Signal Structure" tab of the "Modulation & Signal Description" dialog box, see
Remote command:
[SENSe:]DDEMod:SEARch:BURSt:AUTO on page 309
Measuring only if burst was found
If enabled, measurement results are only displayed (and are only averaged) if a valid burst has been found. When measuring bursted signals that are averaged over several measurements, it is recommended that you enable this option so that erroneous measurements do not affect the result of averaging.
Remote command:
[SENSe:]DDEMod:SEARch:BURSt:MODE on page 309
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Burst and Pattern Configuration
Burst Configuration
The conditions under which a burst is detected in the captured data can be configured either manually or automatically according to the defined signal structure settings (see
Remote command:
[SENSe:]DDEMod:SEARch:BURSt:CONFigure:AUTO on page 309
Search Tolerance ← Burst Configuration
Defines the number of symbols that may differ from the burst length without influencing the burst detection. A search tolerance of 5, for example, with a minimum and maximum burst length of 100, will detect bursts that are 95 to 100 symbols long. (The minimum and maximum burst length is defined in the
settings
Note: Due to the fact that the VSA does not have knowledge of the ramp length, there is an uncertainty in the burst search algorithm. Thus, setting this parameter to "0" will result in a failed burst search for most signals.
Remote command:
[SENSe:]DDEMod:SEARch:BURSt:TOLerance on page 310
Min Gap Length ← Burst Configuration
Represents the minimum distance (in symbols) between adjacent bursts. The default value is 1 symbol in order to make sure that the burst search finds bursts that are very close to each other. However, in case the capture buffer does not contain very close bursts, it is recommended that you increase the value. This makes the burst search faster and also more robust for highly distorted signals.
Note that this parameter only influences the robustness of the burst search. It should not be used to explicitly exclude certain bursts from the measurement. For example, setting the minimum gap length to 100 symbols does not ensure that the burst search does not find bursts that have a very small gap.
Remote command:
[SENSe:]DDEMod:SEARch:BURSt:GLENgth[:MINimum] on page 309
5.7.2 Pattern Search
The "Pattern Search" settings define when a pattern is detected in the evaluated signal.
A live preview of the capture buffer with the current settings is displayed in the preview area at the bottom of the dialog box. The preview area is not editable directly.
The "Pattern Search" settings are displayed when you do one of the following:
● Select the "Burst/Pattern" button from the "Overview".
● Select the "Burst/Pattern Search" softkey from the main VSA menu.
Then switch to the "Pattern Search" tab.
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Burst and Pattern Configuration
Enabling Pattern Searches
Enables or disables pattern searches. If "Auto" is selected, pattern search is enabled only if the signal structure defines a pattern in the signal (in the "Signal Structure" tab
of the "Modulation & Signal Description" dialog box, see "Pattern Settings" on page 140).
Remote command:
[SENSe:]DDEMod:SEARch:SYNC:STATe on page 312
[SENSe:]DDEMod:SEARch:SYNC:AUTO on page 311
I/Q Correlation Threshold
The I/Q correlation threshold decides whether a match is accepted or not during a pat-
tern search (see also chapter 4.4.2, "I/Q Pattern Search" , on page 92). If the parameter
is set to 100%, only I/Q patterns that match totally with the input signal are found. This is only the case for infinite SNR.
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Burst and Pattern Configuration
If the threshold "Auto" option is enabled, the default value of 90% is used. As long as the pattern is found, there is no need to change this parameter. However, if the pattern is very short (approximately < 10 symbols) or if the signal is highly distorted, tuning this parameter helps the pattern search to succeed. To define a threshold manually, disable the "Auto" option.
Remote command:
[SENSe:]DDEMod:SEARch:SYNC:IQCThreshold on page 311
[SENSe:]DDEMod:SEARch:PATTern:CONFigure:AUTO on page 310
Meas only if Pattern Symbols Correct
If enabled, measurement results are only displayed (and are only averaged) if a valid pattern has been found. When measuring signals that contain a pattern and are averaged over several measurements, it is recommended that you enable this option so that erroneous measurements do not affect the result of averaging.
Remote command:
[SENSe:]DDEMod:SEARch:SYNC:MODE on page 311
Selected Pattern for Search
Indicates which of the patterns that are assigned to the current standard is selected and will be searched for.
The selected pattern is indicated for information only and cannot be edited here, only in
the "Signal Structure" settings, see "Name" on page 140).
Remote command:
[SENSe:]DDEMod:SEARch:SYNC:SELect on page 312
Pattern Found
Indicates whether a pattern was found in the currently captured data.
5.7.3 Pattern Configuration
For common signal standards, the patterns to be searched for in the captured signal are predefined in the VSA application. In addition, new patterns can be defined and assigned to a signal standard manually.
Patterns are configured in the "Advanced Pattern Settings" dialog box which is displayed when you do one of the following:
● Select the "Pattern Config" softkey in the main VSA menu.
● In the "Signal Description" dialog box (see
button.
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Burst and Pattern Configuration
Standard Patterns - selecting an assigned pattern
The "Standard Patterns" are the patterns assigned to the currently selected standard.
You can add existing patterns to the standard or remove patterns already assigned to the standard. The highlighted pattern is currently selected for pattern search.
Remote command:
[SENSe:]DDEMod:SEARch:SYNC:SELect on page 312
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Burst and Pattern Configuration
Removing patterns from a standard
Removes the assignment of the selected patterns to the standard. The patterns are removed from the "Standard Patterns" list, but not deleted.
Remote command:
[SENSe:]DDEMod:SEARch:SYNC:PATTern:REMove on page 315
Adding patterns to a standard
Adds the selected patterns in the list of available patterns ("All Patterns") to the list of assigned patterns ("Standard Patterns").
For details see
"To add a predefined pattern to a standard" on page 214.
Remote command:
[SENSe:]DDEMod:SEARch:SYNC:PATTern:ADD on page 315
Displaying available patterns
The "All Patterns" list contains the patterns available in the VSA application.
You can assign available patterns to the selected standard, edit existing or define new patterns.
For details on managing standard patterns, see
chapter 8.2.2.3, "How to Manage Patterns" , on page 217
The list can be filtered using the following functions:
Prefix ← Displaying available patterns
Shows only patterns that contain the specified prefix.
Show Compatible/ Show All ← Displaying available patterns
Shows only patterns that are compatible to the selected modulation mode or all patterns (regardless of the selected standard).
Edit
Opens the "Edit Pattern" dialog box to edit the pattern definition. See chapter 5.7.4,
"Pattern Definition" , on page 171.
For details on defining a pattern, see
example "Defining a pattern" on page 216.
Remote command:
[SENSe:]DDEMod:SEARch:SYNC:NAME on page 314
[SENSe:]DDEMod:SEARch:SYNC:COMMent on page 312
[SENSe:]DDEMod:SEARch:SYNC:DATA on page 313
[SENSe:]DDEMod:SEARch:SYNC:TEXT on page 315
Save As
Saves a copy of an existing pattern under a new name.
Remote command:
[SENSe:]DDEMod:SEARch:SYNC:COPY on page 313
New
Opens the "Pattern" dialog box to create a new pattern definition. See chapter 5.7.4,
"Pattern Definition" , on page 171.
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Burst and Pattern Configuration
For details on defining a pattern, see
example "Defining a pattern" on page 216.
Remote command:
[SENSe:]DDEMod:SEARch:SYNC:NAME on page 314
[SENSe:]DDEMod:SEARch:SYNC:COMMent on page 312
[SENSe:]DDEMod:SEARch:SYNC:DATA on page 313
[SENSe:]DDEMod:SEARch:SYNC:TEXT on page 315
Delete
Deletes the selected patterns. Any existing assignments to other standards are removed.
Remote command:
[SENSe:]DDEMod:SEARch:SYNC:DELete on page 313
Pattern details
Pattern details for the currently focussed pattern are displayed at the upper right-hand side of the dialog box. You can refer to these details, for example, when you want to add a new pattern to the standard and want to make sure you have selected the correct one.
Pattern Search On
If enabled, the VSA application searches for the selected pattern. This setting is identi-
cal to the setting in the "Pattern Search" dialog box (see "Enabling Pattern Searches" on page 167).
Remote command:
[SENSe:]DDEMod:SEARch:SYNC:STATe on page 312
Meas only if Pattern Symbols Correct
If enabled, measurement results are only displayed (and are only averaged) if a valid pattern has been found. When measuring signals that contain a pattern and are averaged over several measurements, it is recommended that you enable this option so that erroneous measurements do not affect the result of averaging.
Remote command:
[SENSe:]DDEMod:SEARch:SYNC:MODE on page 311
5.7.4 Pattern Definition
New patterns can be defined and then assigned to a standard. Patterns are defined in the "New Pattern" dialog box which is displayed when you select the "New" button in the "Advanced Pattern Settings" dialog box.
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Burst and Pattern Configuration
For details on defining a pattern, see
example "Defining a pattern" on page 216.
Name
Pattern name that will be displayed in selection list
Remote command:
[SENSe:]DDEMod:SEARch:SYNC:NAME on page 314
Description
Optional description of the pattern which is displayed in the pattern details
Remote command:
[SENSe:]DDEMod:SEARch:SYNC:TEXT on page 315
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Result Range Configuration
Mod. order
The order of modulation, e.g. 8 for an 8-PSK.
Remote command:
[SENSe:]DDEMod:SEARch:SYNC:NSTate on page 314
Symbols
The pattern definition is a symbol table consisting of one or more symbols. The number of symbols is indicated as the "Size" to the left of the symbol table.
A scrollbar beneath the input area alows you to scroll through the table for long patterns. The numbers beneath the scrollbar indicate the sequential number of the following symbols, from left to right:
● the first symbol
● the currently selected symbol
● the last symbol
Remote command:
[SENSe:]DDEMod:SEARch:SYNC:DATA on page 313
Symbol format ← Symbols
Defines the format in which each symbol is defined: hexadecimal, decimal or binary
Adding symbols ← Symbols
Adds a new symbol in the symbol table to the left of the currently selected symbol.
Removing symbols ← Symbols
Removes the currently selected symbol in the symbol table.
Comment
Optional comment for the pattern, displayed in the pattern details (kept for compatibility with FSQ)
Remote command:
[SENSe:]DDEMod:SEARch:SYNC:COMMent on page 312
5.8 Result Range Configuration
The result range determines which part of the capture buffer, burst or pattern is displayed. For more information, see
chapter 4.6, "Measurement Ranges" , on page 116.
A visualization of the result display with the current settings is displayed in the visualization area at the bottom of the dialog box.
The "Result Range" settings are displayed when you do one of the following:
● Select the "Cut Result Ranges" button from the "Overview".
● Select the "Range Settings" softkey from the main VSA menu.
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Result Range Configuration
Result Length
Defines the number of symbols that are to be demodulated. All traces over time are displayed over the result range.
Remote command:
[SENSe:]DDEMod:TIME on page 317
Reference
Defines the reference for the result range alignment.
The result of the current setting is displayed in the visualization area of the dialog box.
"Capture" the capture buffer
"Burst"
"Pattern" the detected burst the detected pattern
Remote command:
CALCulate<n>:TRACe<t>:ADJust[:VALue] on page 317
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Demodulation Settings
Alignment
Defines the type of alignment of the result range to the reference source. The result of the current setting is displayed in the visualization area of the dialog box.
Remote command:
CALCulate<n>:TRACe<t>:ADJust:ALIGnment[:DEFault] on page 316
Offset
Defines the offset of the result range to the alignment reference. The result of the current setting is displayed in the visualization area of the dialog box.
Note: Note the following restrictions to this parameter:
● An offset < 0 is not possible if you align the result range to the left border of the capture buffer.
● An offset that moves the pattern outside the result range is not allowed. For example, if you align the result to the left border of the pattern, only offsets ≦ 0 are allowed. Otherwise, you would never be able to find the pattern within the result range.
Remote command:
CALCulate<n>:TRACe<t>:ADJust:ALIGnment:OFFSet on page 316
Symbol Number at <Reference> Start
Defines the number of the symbol which marks the beginning of the alignment reference source (burst, capture buffer or pattern). The result of the current setting is displayed in the visualization area of the dialog box.
In effect, this setting defines an offset of the x-axis (in addition to the one defined for the signal structure, see
Note: When you define the "Symbol Number at <Reference> Start" remember to take the offset defined for the signal structure into consideration (see
The "Symbol Number at Pattern Start" refers to the first symbol of the pattern offset, not the first symbol of the pattern.
Remote command:
DISPlay[:WINDow<n>]:TRACe<t>:X[:SCALe]:VOFFset on page 317
5.9 Demodulation Settings
During demodulation of the vector signal some undesired effects that may occur during transmission can be compensated for. Furthermore, you can influence the synchronization process.
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Demodulation Settings
5.9.1 Demodulation - Compensation
Note that compensation for all the listed distortions can result in lower EVM values.
The "Demodulation" settings are displayed when you do one of the following:
● Select the "Demodulation" button from the "Overview".
● Select the "Demod/Meas Filter" softkey from the main VSA menu.
A live preview of the constellation with the current settings is displayed in the preview area at the bottom of the dialog box. The preview area is not editable directly.
Demodulation settings depend on the used modulation.
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Demodulation Settings
Fig. 5-3: Demodulation settings for PSK, MSK and QAM modulation
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Demodulation Settings
Fig. 5-4: Demodulation settings for FSK modulation
Compensate for... (PSK, MSK, ASK, QAM)
If enabled, compensation for various effects is taken into consideration during demodulation. Thus, these distortions are not shown in the calculated error values.
Note: Note that compensation for all the listed distortions can result in lower EVM values.
● I/Q Offset (default: on)
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Demodulation Settings
● I/Q Imbalance
● Amplitude Droop (default: on)
● Symbol Rate Error (required to display the SRE in the Result Summary)
● Channel (default: on)
Note that channel distortion can only be determined if the equalizer is on (see
"State" on page 179). Thus, compensation can only be disabled if the equalizer is
on.
By default, channel compensation is enabled to improve accuracy of the error results. If compensation is disabled, the EVM is calculated from the original input signal with channel distortions.
For details on these effects see
chapter 4.5.1.3, "Modulation Errors" , on page 102.
Remote command:
[SENSe:]DDEMod:NORMalize:IQOFfset on page 325
[SENSe:]DDEMod:NORMalize:IQIMbalance on page 325
[SENSe:]DDEMod:NORMalize:ADRoop on page 324
[SENSe:]DDEMod:NORMalize:SRERror on page 325
[SENSe:]DDEMod:NORMalize:CHANnel on page 324
Compensate for... (FSK)
If enabled, compensation for various effects is taken into consideration during demodulation. Thus, these distortions are not shown in the calculated error values.
● Carrier Frequency Drift
● FSK Deviation Error
● Symbol Rate Error
For details on these effects see
chapter 4.5.2.3, "Modulation Errors" , on page 114.
Remote command:
[SENSe:]DDEMod:NORMalize:CFDRift on page 324
[SENSe:]DDEMod:NORMalize:FDERror on page 324
[SENSe:]DDEMod:NORMalize:SRERror on page 325
Equalizer Settings
The equalizer can compensate for a distorted transmission of the input signal or improve accuracy in estimating the reference signal.
For details see
chapter 4.4.5, "The Equalizer" , on page 97.
State ← Equalizer Settings
Activates or deactivates the equalizer to compensate for a distorted channel.
Remote command:
[SENSe:]DDEMod:EQUalizer[:STATe] on page 322
Mode ← Equalizer Settings
Defines the operating mode of the equalizer.
"Normal" Determines the filter values from the difference between the ideal
(reference) signal and the measured signal. Normal mode is sufficient for small distortions and performance remains high.
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Demodulation Settings
"Tracking" The results of the equalizer in the previous sweep are considered to calculate the new filter until adaquate results are obtained. This
"learning" effect allows for powerful removement of larger distortions within a minimum of sweeps. During the tracking phase calculation of the equalizer requires additional processing time.
"Freeze" The filter is no longer changed, the current equalizer values are used for subsequent sweeps.
A user-defined equalizer loaded from a file is used.
"User"
"Averaging" The results of the equalizer in all previous sweeps (since the instrument was switched on or the equalizer was reset) are considered to calculate the new filter. To start a new averaging process, select the
Reset Equalizer button. Calculation of the equalizer requires addi-
tional processing time.
Remote command:
[SENSe:]DDEMod:EQUalizer:MODE on page 321
Filter Length ← Equalizer Settings
Defines the length of the equalizer in symbols. The longer the equalizer, the more accurate the filter becomes and the more distortion can be compensated. However, this requires extended calculation time. The shorter the filter length, the less calculation time is required during the equalizer's tracking or averaging phase.
Remote command:
[SENSe:]DDEMod:EQUalizer:LENGth on page 320
Reset Equalizer ← Equalizer Settings
Deletes the data of the currently selected equalizer. After deletion, averaging and tracking starts anew.
This is useful in the rare case that calculation takes a wrong symbol decision into consideration and distorts the signal such that the original signal can no longer be determined.
Remote command:
[SENSe:]DDEMod:EQUalizer:RESet on page 322
Store/Load Current Equalizer ← Equalizer Settings
Saves the current equalizer results to a file, or loads a user-defined equalizer.
The equalizer Mode must be set to USER in order to load a file.
Remote command:
[SENSe:]DDEMod:EQUalizer:SAVE on page 322
[SENSe:]DDEMod:EQUalizer:LOAD on page 321
5.9.2 Advanced Demodulation (Synchronization)
You can influence the synchronization process and calculation of error values during demodulation.
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Demodulation Settings
The "Advanced Demodulation" settings are displayed when you do one of the following:
● Select the "Demodulation" button from the "Overview".
● Select the "Demod/Meas Filter" softkey from the main VSA menu.
Then switch to the "Demodulation - Advanced" tab.
A live preview of the constellation with the current settings is displayed in the preview area at the bottom of the dialog box. The preview area is not editable directly.
Normalize EVM to
Normalizes the EVM to the specified power value.
This setting is not available for MSK or FSK modulation.
● Max Ref Power
Maximum power of the reference signal at the symbol instants.
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Demodulation Settings
● Mean Ref Power mean power of the reference signal at the symbol instants.
● Mean Constellation Power
Mean expected power of the measurement signal at the symbol instants
● Max Constellation Power
The maximum expected power of the measurement signal at the symbol instants
Remote command:
[SENSe:]DDEMod:ECALc[:MODE] on page 318
Optimization
Determines the method used to calculate the result parameters. The required method depends on the used standard and is set according to the selected standard by default.
"Minimize RMS
Error"
"Minimize
EVM"
Optimizes calculation such that the RMS of the error vector is minimal.
Optimizes calculation such that EVM is minimal.
Remote command:
[SENSe:]DDEMod:OPTimization on page 325
Estimation Points/Sym
During synchronization, the measurement signal is matched to the reference signal and various signal parameters are calculated. You can define how many sample points are used for this calculation at each symbol.
For more information on estimation points per symbol see
chapter 4.7, "Display Points vs Estimation Points per Symbol" , on page 121.
You can set the estimation points manually or let the VSA application decide how many estimation points to use.
If automatic mode is enabled, the VSA application uses the following settings, depending on the modulation type:
Modulation
PSK, QAM
Offset QPSK
FSK, MSK
Est. Points
1
2
Capture Oversampling
For manual mode, the following settings are available:
"1" the estimation algorithm takes only the symbol time instants into account
"2" two points per symbol instant are used (required for Offset QPSK)
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Demodulation Settings
"Capture Oversampling" the number of samples per symbol defined in the signal capture settings is used (see
"Sample Rate" on page 156), i.e. all sample time
instants are weighted equally
Remote command:
[SENSe:]DDEMod:EPRate:AUTO on page 319
[SENSe:]DDEMod:EPRate[:VALue] on page 320
Coarse Synchronization
It is not only possible to check whether the pattern is part of the signal, but also to use the pattern for synchronization, in order to obtain the correct reference signal.
For details on synchronization see
chapter 4.4, "Overview of the Demodulation Process" , on page 88.
If "Auto" mode is selected, the detected data is used. In manual mode you can select one of the following settings:
"Data"
"Pattern"
(Default): the detected data is used for synchronization, i.e. unknown symbols
Use this setting if no pattern is available or if the pattern is short or does not have suitable synchronization properties, e.g. a pattern that consists of only one repeated symbol.
Known symbols from a defined pattern are used for synchronization
Depending on the signal, using the pattern can speed up your measurement considerably and make it more robust against high carrier frequency offsets.
Make sure that the pattern is suitable for synchronization, e.g. a GSM pattern.
Remote command:
[SENSe:]DDEMod:SEARch:PATTern:SYNC:AUTO on page 326
[SENSe:]DDEMod:SEARch:PATTern:SYNC[:STATe] on page 326
Fine Synchronization
In addition to the coarse synchronization used for symbol decisions, a fine synchronization is available to calculate various results from the reference signal, e.g. the EVM.
However, when the signal is known to have a poor transmission quality or has a high noise level, false symbol decisions are more frequent, which may cause spikes in the
EVM results.
To improve these calculations the reference signal can be estimated from a smaller area that includes a known symbol sequence in the input signal. In this case, the results for the limited reference area are more precise, at the cost of less accurate results outside this area. Thus, the result range should be set to the length of the reference area. The reference area can be defined either using a pattern or using a known data sequence from a Known Data file. If no predefined data sequences are available for the signal, the detected data is used by default.
If "Auto" mode is selected and a Known Data file has been loaded and activated for use, the known data sequences are used. Otherwise, the detected data is used.
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Demodulation Settings
Note: You can define a maximum symbol error rate (SER) for the known data in reference to the evaluated data. If the SER of the known data exceeds this limit, the default synchronization using the detected data is performed.
"Known Data" The reference signal is defined as the data sequence from the loaded
Known Data file that most closely matches the measured data.
"Pattern"
"Detected
Data"
The reference signal is estimated from the defined pattern.
(Default) The reference signal is estimated from the detected data.
Remote command:
[SENSe:]DDEMod:FSYNc:AUTO on page 322
[SENSe:]DDEMod:FSYNc[:MODE] on page 323
If SER ≤
This setting is only available if "Known Data" is selected for "Fine Synchronization".
You can define a maximum symbol error rate for the known data in reference to the evaluated data. Thus, if a wrong file was mistakenly loaded or the file proves to be unsuitable, it is not used for synchronization. Otherwise the results would be strongly distorted. If the SER of the known data exceeds this limit, the default synchronization using the detected data is performed.
Remote command:
[SENSe:]DDEMod:FSYNc:LEVel on page 322
Offset EVM
The offset EVM is only available for Offset QPSK modulated signals.
Unlike QPSK modulation, the Q component of Offset QPSK modulation is delayed by half a symbol period against the I component in the time domain. The symbol time instants of the I and the Q component therefore do not coincide.
The offset EVM controls the calculation of all results that are based on the error vector.
It affects the EVM, Real/Imag and Vector I/Q result displays as well as the EVM results in the Result Summary (EVM and MER).
You can configure the way the VSA application calculates the error vector results.
If "Offset EVM" is disabled, the VSA application substracts the measured signal from the reference signal to calculate the error vector. This method results in the fact that the error vector contains two symbol instants per symbol period: one that corresponds to the I component and one that corresponds to the Q component.
If "Offset EVM" is enabled, however, the VSA application compensates the delay of the
Q component with respect to the I component in the measurement signal as well as the reference signal before calculating the error vector. That means that the error vector contains only one symbol instant per symbol period.
Remote command:
[SENSe:]DDEMod:ECALc:OFFSet on page 319
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Measurement Filter Settings
5.10 Measurement Filter Settings
The measurement filter can be used to filter both the measured signal and the reference signal, and thus the error vector. You can configure the measurement filter to be used.
For more information on measurement filters see
chapter 4.1.4, "Measurement Filters" , on page 59.
The "Measurement Filter" settings are displayed when you do one of the following:
● Select the "Measurement Filter" button from the "Overview".
● Select the "Demod/Meas Filter" softkey from the main VSA menu.
Then switch to the "Meas Filter" tab.
A live preview of the constellation with the current settings is displayed in the preview area at the bottom of the dialog box. The preview area is not editable directly.
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Measurement Filter Settings
Using the Transmit Filter as a Measurement Filter (Auto)
If the "Auto" option is enabled, the measurement filter is defined automatically depending on the transmit filter specified in the "Modulation" settings (see
Note: If a user-defined transmit filter is selected and the measurement filter is defined automatically, a Low-ISI measurement filter according to the selected user filter is calculated and used.
Remote command:
[SENSe:]DDEMod:MFILter:AUTO on page 327
Type
Defines the measurement filter type, if the
Using the Transmit Filter as a Measurement
setting is not enabled.
"<Predefined
Filter>"
An overview of available measurement filters is provided in chapter A.
3.2, "Measurement Filters" , on page 420.
"User" User-defined filter.
Define the filter using the
For more information on user-defined filters see chapter 4.1.5, "Customized Filters" , on page 61.
"None" No measurement filter is used.
Remote command:
[SENSe:]DDEMod:MFILter[:STATe] on page 327
To turn off the measurement filter.
[SENSe:]DDEMod:MFILter:USER on page 328
To use a user-defined filter.
[SENSe:]DDEMod:MFILter:NAME on page 327
To define the name of the measurement filter.
Load User Filter ← Type
Opens a file-selection dialog box to select the user-defined measurement filter to be used.
This setting is only available if "User" is selected as the "Filter Type".
For detailed instructions on working with user-defined filters see
Select User-Defined Filters" , on page 213.
Remote command:
[SENSe:]DDEMod:MFILter:USER on page 328
Alpha/BT ← Type
Defines the roll-off factor (Alpha) or the filter bandwidth (BT).
The roll-off factor or filter bandwidth are available for RC, RRC and Gauss filters.
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Evaluation Range Configuration
If the measurement mode is automatically selected according to the transmit filter, this setting is identical to the "Alpha/BT" value in the modulation settings (see
Remote command:
Measurement filter:
[SENSe:]DDEMod:MFILter:ALPHa on page 327
Transmit filter: [SENSe:]DDEMod:TFILter:ALPHa on page 283
5.11 Evaluation Range Configuration
The evaluation range defines which range of the result is to be evaluated - either the entire result range or only a specified part of it. The calculated length of the specified range is indicated beneath the entries.
A visualization of the evaluation range (in relation to the result range) with the current settings is displayed at the bottom of the dialog box. The green bar below the trace indicates the defined result range, indented red lines indicate defined start and stop symbols (see
"Evaluation range display" on page 120). The visualization is not editable
directly.
The "Evaluation Range" settings are displayed when you do one of the following:
● Select the "Evaluation Range" button from the "Overview".
● Select the "Range Settings" softkey from the main VSA menu.
Then switch to the "Evaluation Range" tab.
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Adjusting Settings Automatically
For details on the evaluation range see
chapter 4.6, "Measurement Ranges" , on page 116.
Evaluating the Entire Result Range
If enabled, the entire result range is evaluated.
If disabled, you can define a specific part of the result range to be evaluated.
Remote command:
CALCulate<n>:ELIN<startstop>:STATe on page 328
Start / Stop
Defines the symbol in the result range at which evaluation is started and stopped. The start and stop symbols themselves are included in the evaluation range.
Note: Note that the start and stop values are defined with respect to the x-axis includ-
ing an optional offset defined via the Symbol Number at <Reference> Start
parameter.
Remote command:
CALCulate<n>:ELIN<startstop>[:VALue] on page 329
5.12 Adjusting Settings Automatically
Some settings can be adjusted by the R&S FPS automatically according to the current measurement settings. In order to do so, a measurement is performed. The duration of this measurement can be defined automatically or manually.
To activate the automatic adjustment of a setting, select the corresponding function in the AUTO SET menu or in the configuration dialog box for the setting, where available.
Resetting the Automatic Measurement Time (Meastime Auto) ...................................189
Changing the Automatic Measurement Time (Meastime Manual) .............................. 189
Setting the Reference Level Automatically (Auto Level)
Automatically determines the optimal reference level for the current input data. At the same time, the internal attenuators are adjusted so the signal-to-noise ratio is optimized, while signal compression, clipping and overload conditions are minimized.
To determine the optimal reference level, a level measurement is performed on the
R&S FPS.
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Adjusting Settings Automatically
You can change the measurement time for the level measurement if necessary (see
"Changing the Automatic Measurement Time (Meastime Manual)" on page 189).
Remote command:
[SENSe:]ADJust:LEVel on page 332
Resetting the Automatic Measurement Time (Meastime Auto)
Resets the measurement duration for automatic settings to the default value.
Remote command:
[SENSe:]ADJust:CONFigure:DURation:MODE on page 330
Changing the Automatic Measurement Time (Meastime Manual)
This function allows you to change the measurement duration for automatic setting adjustments. Enter the value in seconds.
Remote command:
[SENSe:]ADJust:CONFigure:DURation:MODE on page 330
[SENSe:]ADJust:CONFigure:DURation on page 330
Upper Level Hysteresis
When the reference level is adjusted automatically using the
internal attenuators and the preamplifier are also adjusted. In order to avoid frequent adaptation due to small changes in the input signal, you can define a hysteresis. This setting defines an upper threshold the signal must exceed (compared to the last measurement) before the reference level is adapted automatically.
Remote command:
[SENSe:]ADJust:CONFigure:HYSTeresis:UPPer on page 331
Lower Level Hysteresis
When the reference level is adjusted automatically using the
internal attenuators and the preamplifier are also adjusted. In order to avoid frequent adaptation due to small changes in the input signal, you can define a hysteresis. This setting defines a lower threshold the signal must fall below (compared to the last measurement) before the reference level is adapted automatically.
Remote command:
[SENSe:]ADJust:CONFigure:HYSTeresis:LOWer on page 331
Auto Scale Once/Auto Scale Window
If enabled, both the x-axis and y-axis are automatically adapted to the current measurement results (only once, not dynamically) in the selected window.
To adapt the range of all screens together, use the Auto Scale All function.
Remote command:
DISPlay[:WINDow<n>]:TRACe<t>:Y[:SCALe]:AUTO ONCE on page 330
Auto Scale All
Adapts the x-axis and y-axis to the current measurement values (only once, not dynamically) in all measurement windows.
Remote command:
DISPlay[:WINDow<n>]:TRACe<t>:Y[:SCALe]:AUTO:ALL on page 330
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Trace Settings
6 Analysis
General result analysis settings concerning the trace, markers, windows etc. can be configured via the "Analysis" button in the "Overview". They are identical to the analysis functions in the base unit except for the special window functions.
Window-specific configuration
The settings in the "Analysis" dialog box are specific to the selected window. Thus, the
"Analysis" button is only available in the "Overview" if the "Specifics for" option is enabled. To configure the settings for a different VSA window, select the window outside the displayed dialog box, or select the window from the "Specifics for" selection list in the dialog box.
6.1 Trace Settings
The trace settings determine how the measured data is analyzed and displayed in the window. Depending on the result display, between 1 and 6 traces may be displayed.
The "Trace" settings are displayed when you do one of the following:
● Select the "Analysis" button from the "Overview", then select the vertical "Traces" tab.
● Select the TRACE key.
Trace data can also be exported to an ASCII file for further analysis. For details see
chapter 6.2, "Trace Export Settings" , on page 193.
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Trace Settings
Trace 1/Trace 2/Trace 3/Trace 4/Trace 5/Trace 6
Selects the corresponding trace for configuration. The currently selected trace is highlighted orange.
Remote command:
DISPlay[:WINDow<n>]:TRACe<t>[:STATe] on page 340
Selected via numeric suffix of TRACe<t> commands
Trace Mode
Defines the update mode for subsequent traces.
The available trace modes depend on the selected result display. Not all evaluations support all trace modes.
For the Magnitude Overview Absolute result display, only the trace modes "Clear/
Write" and "View" are available. For the Magnitude Absolute result display, the trace modes Average, MinHold, MaxHold are applied to the individual result ranges and thus may not provide useful results.
"Clear Write" Overwrite mode: the trace is overwritten by each measurement. This is the default setting.
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Trace Settings
"Max Hold"
"Min Hold"
"Average"
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
Statistic Count determines the number of averaging procedures.
"View"
"Blank"
The current contents of the trace memory are frozen and displayed.
Removes the selected trace from the display.
Remote command:
DISPlay[:WINDow<n>]:TRACe<t>:MODE on page 339
Evaluation
Defines whether the trace displays the evaluation of the measured signal or the refer-
ence signal (if "Meas & Ref Signal" is used as the evaluation data source, see "Signal
Remote command:
CALCulate<n>:TRACe<t>[:VALue] on page 338
Predefined Trace Settings - Quick Config
Commonly required trace settings have been predefined and can be applied very quickly by selecting the appropriate button.
Function
Preset All Traces
Set Trace Mode
Max | Avg | Min
Set Trace Mode
Max | ClrWrite | Min
Trace Settings
Trace 1: Clear Write
Traces 2-6:
Trace 1:
Trace 2:
Trace 3:
Blank
Max Hold
Average
Min Hold
Traces 4-6:
Trace 1:
Trace 2:
Trace 3:
Traces 4-6:
Blank
Max Hold
Clear Write
Min Hold
Blank
Trace 1/Trace 2/Trace 3/Trace 4 (Softkeys)
Displays the "Traces" settings and focuses the "Mode" list for the selected trace.
Remote command:
DISPlay[:WINDow<n>]:TRACe<t>[:STATe] on page 340
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Trace Export Settings
6.2 Trace Export Settings
The captured (trace) data can also be exported to an ASCII file. The format of these files can be configured.
Data Export Mode
Defines whether raw I/Q data (as captured) or trace data (evaluated) is stored.
Remote command:
FORMat:DEXPort:MODE on page 373
Header
If enabled, a header with scaling information etc. is included in the file.
Remote command:
FORMat:DEXPort:HEADer on page 373
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Markers
Decimal Separator
Defines the decimal separator for floating-point numerals for the data export files. Evaluation programs require different separators in different languages.
Remote command:
FORMat:DEXPort:DSEParator on page 373
Trace ASCII Export
Opens a file selection dialog box and saves the traces of the captured data in ASCII format to the specified file and directory.
Either the traces for the selected window only (see "Specifics for" on page 133) are
exported, or the traces of all windows are exported, one after the other.
For details on the file format see
chapter A.4, "ASCII File Export Format for VSA Data" , on page 421.
Remote command:
MMEMory:STORe<n>:TRACe on page 373
6.3 Markers
Markers help you analyze your measurement results by determining particular values in the diagram. Thus you can extract numeric values from a graphical display.
6.3.1 Individual Marker Settings
In VSA evaluations, up to 5 markers can be activated in each diagram at any time.
Markers are configured in the "Marker" dialog box which is displayed when you do one of the following:
● In the "Overview", select "Analysis", and switch to the vertical "Marker" tab.
● Press the MKR key, then select the "Marker Config" softkey.
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Markers
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 341
CALCulate<n>:DELTamarker<m>[:STATe] on page 342
X-value
Defines the position of the marker on the x-axis.
Remote command:
CALCulate<n>:DELTamarker<m>:X on page 343
CALCulate<n>:MARKer<m>:X on page 342
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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" A normal marker indicates the absolute value at the defined position in the diagram.
"Delta" A delta marker defines the value of the marker relative to the specified reference marker (marker 1 by default).
Remote command:
CALCulate<n>:MARKer<m>[:STATe] on page 341
CALCulate<n>:DELTamarker<m>[:STATe] on page 342
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.
The marker can also be assigned to the currently active trace using the "Marker to
Trace" softkey in the "Marker" menu.
If a trace is turned off, the assigned markers and marker functions are also deactivated.
Remote command:
CALCulate<n>:MARKer<m>:TRACe on page 341
All Markers Off
Deactivates all markers in one step.
Remote command:
CALCulate<n>:MARKer<m>:AOFF on page 341
Couple Windows
If enabled, markers in all diagrams with the same x-axis (time or symbols) have coupled x-values (except for capture buffer display), i.e. if you move the marker in one diagram, it is moved in all coupled diagrams.
Remote command:
CALCulate<n>:MARKer<m>:LINK on page 341
6.3.2 Marker Search Settings
Several functions are available to set the marker to a specific position very quickly and easily. In order to determine the required marker position, searches may be performed.
The search results can be influenced by special settings.
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Markers
These settings are available as softkeys in the "Marker To" menu, or in the "Search" tab of the "Marker" dialog box. To display this tab, do one of the following:
● Press the MKR key, then select the "Marker Config" softkey. Then select the horizontal "Search Settings" tab.
● In the "Overview", select "Analysis", and switch to the vertical "Marker Config" tab.
Then select the horizontal "Search Settings" tab.
Search Mode for Next Peak
Selects the search mode for the next peak search.
"Left"
"Absolute"
Determines the next maximum/minimum to the left of the current peak.
Determines the next maximum/minimum to either side of the current peak.
"Right" Determines the next maximum/minimum to the right of the current peak.
Remote command:
chapter 11.7.2.2, "Marker Search and Positioning Settings" , on page 344
Real / Imag Plot
Defines whether marker search functions are performed on the real or imaginary trace of the "Real/Imag" measurement.
Remote command:
CALCulate<n>:MARKer<m>:SEARch on page 347
Search Limits (Left / Right)
If activated, limit lines are defined and displayed for the search. Only results within the limited search range are considered.
Remote command:
CALCulate<n>:MARKer<m>:X:SLIMits[:STATe] on page 348
CALCulate<n>:MARKer<m>:X:SLIMits:LEFT on page 347
CALCulate<n>:MARKer<m>:X:SLIMits:RIGHT on page 348
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Markers
6.3.3 Marker Positioning Functions
The following functions set the currently selected marker to the result of a peak search.
These functions are available as softkeys in the "Marker To" menu, which is displayed when you press the MKR -> key.
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 346
CALCulate<n>:DELTamarker<m>:MAXimum[:PEAK] on page 345
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 346
CALCulate<n>:DELTamarker<m>:MAXimum:NEXT on page 345
Max |Peak|
Sets the active marker/delta marker to the largest absolute peak value (maximum or minimum) of the selected trace.
Remote command:
CALCulate<n>:MARKer<m>:MAXimum:APEak on page 346
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 347
CALCulate<n>:DELTamarker<m>:MINimum[:PEAK] on page 345
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 347
CALCulate<n>:DELTamarker<m>:MINimum:NEXT on page 345
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Modulation Accuracy Limit Lines
6.4 Modulation Accuracy Limit Lines
The results of a modulation accuracy measurement can be checked for violation of defined limits automatically (see
"Modulation Accuracy" on page 17).
Limits and the limit check are configured in the "Limits" dialog box that is displayed when you press the "ModAcc Limits Config" softkey in the "Lines" menu.
For details on working with limits see
chapter 8.3.2, "How to Check Limits for Modulation Accuracy" , on page 225.
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Modulation Accuracy Limit Lines
Checking Modulation Accuracy Limits
Activates or deactivates evaluation of modulation accuracy limits in the result summary.
Remote command:
CALCulate<n>:LIMit:MACCuracy:STATe on page 349
Set to Default
Restores the default limits and deactivates all checks.
Remote command:
CALCulate<n>:LIMit:MACCuracy:DEFault on page 349
Current/Mean/Peak
Defines and activates the limits for the currently measured value, the mean and the peak value on separate tabs. Note that the limits for the current and peak values are always the same.
Limit Value ← Current/Mean/Peak
Define the limit with which the currently measured, mean or peak value is to be compared. A different limit value can be defined for each result type. Depending on the modulation type, different result types are available.
Remote command Result type
PSK, MSK, QAM:
EVM RMS
EVM Peak
Phase Err Rms
Phase Err Peak
Magnitude Err Rms
Magnitude Err Peak
Carr Freq Err
Rho
IQ Offset
CALCulate<n>:LIMit:MACCuracy:EVM:RCURrent:VALue on page 352
CALCulate<n>:LIMit:MACCuracy:EVM:PCURrent:VALue on page 352
CALCulate<n>:LIMit:MACCuracy:PERRor:RCURrent:VALue on page 353
CALCulate<n>:LIMit:MACCuracy:PERRor:PCURrent:VALue on page 353
CALCulate<n>:LIMit:MACCuracy:MERRor:RCURrent:VALue on page 353
CALCulate<n>:LIMit:MACCuracy:MERRor:PCURrent:VALue on page 353
CALCulate<n>:LIMit:MACCuracy:CFERror:CURRent:VALue on page 351
CALCulate<n>:LIMit:MACCuracy:RHO:CURRent:VALue on page 354
CALCulate<n>:LIMit:MACCuracy:OOFFset:CURRent:VALue on page 353
FSK modulation only:
Freq Err Rms
Freq Err Peak
CALCulate<n>:LIMit:MACCuracy:FERRor:RCURrent:VALue on page 352
CALCulate<n>:LIMit:MACCuracy:FERRor:PCURrent:VALue on page 352
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Display and Window Configuration
Result type
Magnitude Err Rms
Magnitude Err Peak
FSK Dev Err
Carr Freq Err
Remote command
CALCulate<n>:LIMit:MACCuracy:MERRor:RCURrent:VALue on page 353
CALCulate<n>:LIMit:MACCuracy:MERRor:PCURrent:VALue on page 353
CALCulate<n>:LIMit:MACCuracy:FERRor:PCURrent:VALue on page 352
CALCulate<n>:LIMit:MACCuracy:CFERror:CURRent:VALue on page 351
Check ← Current/Mean/Peak
Considers the defined limit value in the limit check, if checking is activated.
Remote command:
CALCulate<n>:LIMit:MACCuracy:<ResultType>:<LimitType>:STATe on page 350
6.5 Display and Window Configuration
The captured I/Q data can be evaluated using various different methods without having to start a new measurement.
As opposed to the R&S FPS I/Q Analyzer application or other applications, in VSA configuring the result display requires two steps:
1. Display Configuration: In the first step, you select the data source for the evaluation and the window placement in the SmartGrid.
The SmartGrid mode is activated automatically when you select the "Display Config" softkey from the main VSA menu or the "Display Config" button in the Overview. Note, however, that this button is only displayed in the general Overview, not for window-specific configuration ("Specifics for" must be disabled).
The default evaluation for the selected data source is displayed in the window.
Up to 16 result displays can be displayed simultaneously in separate windows. The
VSA evaluation methods are described in
chapter 3, "Measurements and Result
For details on working with the SmartGrid see the R&S FPS Getting Started manual.
2. Window Configuration: In a second step, you can select a different evaluation method (result type) for the window, based on the data source selected in the "Display Configuration".
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Display and Window Configuration
6.5.1 Window Configuration
For each window you can select a different evaluation method (result type), based on the data source selected in the "Display Configuration". Further window settings are available for some result types.
The "Window Configuration" is displayed when you select the "Window Config" softkey from the main VSA menu.
Some settings are only displayed after you select the "More" button in the dialog box.
To hide these settings, select the "Less" button.
Signal Source
Data source as selected in the "Display Configuration" (see
default result type for the new data source is activated for the current window.
Remote command:
Result Type
The result type defines the evaluation method used in the current window.
The available result types in VSA are described in chapter 3.2, "Result Types in VSA" , on page 18.
Remote command:
CALCulate<n>:FORMat on page 366
Result Type Transformation
For certain result types it is not only possible to see the common "over time" representation of the measurement, but also the spectrum or the statistics (in form of a histogram). These are the transformations of the results.
These settings are not available for symbol evaluation, i.e. the following signal sources:
● Symbols
● Modulation Accuracy
"Normal"
"Spectrum"
Evaluation in time domain
X-axis displays time values.
Evaluation in frequency domain
X-axis displays frequency values. The usable I/Q bandwidth is indicated in the display.
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Display and Window Configuration
"Statistics" Statistical evaluation (histogram)
X-axis displays former y-values. Y-axis displays statistical information:
● Trace 1: the probability of occurrence of a certain value is plotted against the value
● Trace 2: the cumulated probability of occurance is plotted against the value.
Remote command:
CALCulate<n>:DDEM:SPECtrum[:STATe] on page 365
CALCulate<n>:STATistics:CCDF[:STATe] on page 368
Highlight Symbols
If enabled, the symbol instants are highlighted as squares in the window for measured and reference signals in time (normal) display, as well as error displays.
Only evaluations that are based on symbols (e.g. constellations or traces) support this function.
Remote command:
DISPlay[:WINDow<n>]:TRACe:SYMBol on page 370
Display Points/Sym
Defines the number of display points that are displayed per symbol. If more points per
symbol are selected than the defined Sample Rate
, the additional points are interpolated for the display. The more points are displayed per symbol, the more detailed the trace becomes.
For more information see
chapter 4.7, "Display Points vs Estimation Points per Symbol" , on page 121
Note: If the capture buffer is used as the signal source, the Sample Rate
defines the number of displayed points per symbol; the "Display Points/Sym" parameter is not available.
If "Auto" is enabled, the Sample Rate value is used.
Alternatively, select the number of points to be displayed per symbol manually. The available values depend on the source type.
"1"
"2, 4, 8, 16,
32" only the symbol time instants are displayed more points are displayed than symbols
"Capture Oversampling" the number of samples per symbol defined in the signal capture set-
tings are displayed (see "Sample Rate" on page 156)
Remote command:
DISPlay[:WINDow<n>]:PRATe[:VALue] on page 370
DISPlay[:WINDow<n>]:PRATe:AUTO on page 369
Oversampling
Defines the sample basis for statistical evaluation. This setting is only available for the result type transformation "Statistics".
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Zoom Functions
Fig. 6-1: Statistics measurement: window C: measured signal (symbols highlighted); window A: statistics for all trace points; window B: statistics for symbol instants only
"Symbols only" Statistics are calculated for symbol instants only
See window B in
.
"Infinite" Statistics are calculated for all trace points (symbol instants and intermediate times)
See window A in
.
"Auto" Oversampling is automatically set to "Symbols only" (Statistics are calculated for symbol instants only).
Remote command:
CALCulate<n>:STATistics:MODE on page 368
6.6 Zoom Functions
The zoom functions are only available from the toolbar.
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Zoom Functions
Single Zoom
A single zoom replaces the current diagram by a new diagram which displays an enlarged extract of the trace. This function can be used repetitively until the required details are visible.
Remote command:
DISPlay[:WINDow<n>]:ZOOM:STATe on page 356
DISPlay[:WINDow<n>]:ZOOM:AREA on page 356
Multiple Zoom
In multiple zoom mode, you can enlarge several different areas of the trace simultaneously. An overview window indicates the zoom areas in the original trace, while the zoomed trace areas are displayed in individual windows. The zoom area that corresponds to the individual zoom display is indicated in the lower right corner, between the scrollbars.
Remote command:
DISPlay[:WINDow<n>]:ZOOM:MULTiple<zoom>:STATe on page 357
DISPlay[:WINDow<n>]:ZOOM:MULTiple<zoom>:AREA on page 356
Restore Original Display
Restores the original display and closes all zoom windows.
Remote command:
DISPlay[:WINDow<n>]:ZOOM:STATe on page 356 (single zoom)
DISPlay[:WINDow<n>]:ZOOM:MULTiple<zoom>:STATe on page 357 (for each
multiple zoom window)
Deactivating Zoom (Selection mode)
Deactivates any zoom mode.
Selecting a point in the display no longer invokes a zoom, but selects an object.
Remote command:
DISPlay[:WINDow<n>]:ZOOM:STATe on page 356 (single zoom)
DISPlay[:WINDow<n>]:ZOOM:MULTiple<zoom>:STATe on page 357 (for each
multiple zoom window)
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Import/Export Functions
7 I/Q Data Import and Export
Baseband signals mostly occur as so-called complex baseband signals, i.e. a signal representation that consists of two channels; the in phase (I) and the quadrature (Q) channel. Such signals are referred to as I/Q signals. I/Q signals are useful because the specific RF or IF frequencies are not needed. The complete modulation information and even distortion that originates from the RF, IF or baseband domains can be analyzed in the I/Q baseband.
Importing and exporting I/Q signals is useful for various applications:
● Generating and saving I/Q signals in an RF or baseband signal generator or in external software tools to analyze them with the R&S FPS later
● Capturing and saving I/Q signals with an RF or baseband signal analyzer to analyze them with the R&S FPS or an external software tool later
As opposed to storing trace data, which may be averaged or restricted to peak values,
I/Q data is stored as it was captured, without further processing. The data is stored as complex values in 32-bit floating-point format. Multi-channel data is not supported. The
I/Q data is stored in a format with the file extension .iq.tar.
For a detailed description see the R&S FPS I/Q Analyzer and I/Q Input User Manual.
Export only in MSRA mode
In MSRA mode, I/Q data can only be exported to other applications; I/Q data cannot be imported to the MSRA Master or any MSRA applications.
7.1 Import/Export Functions
The following import and export functions are available via softkeys in the "Save/
Recall" menu which is displayed when you select the "Save" or "Open" icon in the toolbar.
Some functions for particular data types are (also) available via softkeys or dialog boxes in the corresponding menus, e.g. trace data or marker peak lists.
For a description of the other functions in the "Save/Recall" menu see the R&S FPS
User Manual.
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Import/Export Functions
Import
Provides functions to import data.
I/Q Import ← Import
Opens a file selection dialog box to select an import file that contains IQ data. This function is only available in single sweep mode and only in applications that process
I/Q data, such as the I/Q Analyzer or optional applications.
Note that the I/Q data must have a specific format as described in the R&S FPS I/Q
Analyzer and I/Q Input User Manual.
Remote command:
MMEMory:LOAD:IQ:STATe on page 390
Export
Opens a submenu to configure data export.
Export Trace to ASCII File ← Export
Opens a file selection dialog box and saves the selected trace in ASCII format (.dat) to the specified file and directory.
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 that only the trace data in the currently displayed result range of the capture buffer is exported. For the Magnitude Absolute Overview result display, the trace contains a maximum of 25,000 points.
Note: Secure user mode.
In secure user mode, settings that are to be stored on the instrument are stored to volatile memory, which is restricted to 256 MB. Thus, a "Memory full" error may 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 User Manual.
Remote command:
MMEMory:STORe<n>:TRACe on page 373
I/Q Export ← Export
Opens a file selection dialog box to select an export file to which the IQ data will be stored. This function is only available in single sweep mode, and only in applications that process I/Q data, such as the I/Q Analyzer or optional applications.
Note: Secure user mode.
In secure user mode, settings that are to be stored on the instrument are stored to volatile memory, which is restricted to 256 MB. Thus, a "Memory full" error may 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.
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How to Export and Import I/Q Data
For details see "Protecting Data Using the Secure User Mode" in the "Data Management" section of the R&S FPS User Manual.
Remote command:
MMEMory:STORe<n>:IQ:STATe on page 391
MMEMory:STORe<n>:IQ:COMMent on page 390
7.2 How to Export and Import I/Q Data
I/Q data can only be exported in applications that process I/Q data, such as the I/Q
Analyzer or optional applications.
Capturing and exporting I/Q data
1. Press the PRESET key.
2. Press the MODE key and select the "IQ Analyzer" or any other application that supports I/Q data.
3. Configure the data acquisition.
4. Press the RUN SINGLE key to perform a single sweep measurement.
5. Select the "Save" icon in the toolbar.
6. Select the "I/Q Export" softkey.
7. In the file selection dialog box, select a storage location and enter a file name.
8. Select "Save".
The captured data is stored to a file with the extension .iq.tar.
Importing I/Q data
1. Press the MODE key and select the "IQ Analyzer" or any other application that supports I/Q data.
2. If necessary, switch to single sweep mode by pressing the RUN SINGLE key.
3. Select the "Open" icon in the toolbar.
4. Select the "I/Q Import" softkey.
5. Select the storage location and the file name with the .iq.tar file extension.
6. Select "Open".
The stored data is loaded from the file and displayed in the current application.
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Previewing the I/Q data in a web browser
The iq-tar file format allows you to preview the I/Q data in a web browser.
1. Use an archive tool (e.g. WinZip® or PowerArchiver®) to unpack the iq-tar file into a folder.
2. Locate the folder using Windows Explorer.
3. Open your web browser.
4. Drag the I/Q parameter XML file, e.g. example.xml, into your web browser.
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How to Perform VSA According to Digital Standards
8 How to Perform Vector Signal Analysis
Using the VSA option you can perform vector signal analysis measurements using predefined standard setting files, or independently of digital standards using user-defined measurement settings. Such settings can be stored for recurrent use.
Thus, configuring VSA measurements requires one of the following tasks:
● Selecting an existing standard settings file and, if necessary, adapting the measurement settings to your specific requirements.
● Configuring the measurement settings and, if necessary, storing the settings in a file.
● How to Perform VSA According to Digital Standards ............................................210
● How to Perform Customized VSA Measurements ................................................ 212
8.1 How to Perform VSA According to Digital Standards
In order to perform vector signal analysis as specified in digital standards, various predefined settings files for common digital standards are provided for use with the VSA option. In addition, you can create your own settings files for user-specific measurements.
For an overview of predefined standards and settings see chapter A.2, "Predefined
Standards and Settings" , on page 412.
This section provides instructions for the following tasks:
●
"To perform a measurement according to a standard" on page 210
●
"To load predefined settings files" on page 211
●
"To store settings as a standard file" on page 211
●
"To delete standard files" on page 211
●
"To restore standard files" on page 212
To perform a measurement according to a standard
1. Press the MODE key and select the "VSA" application.
2. Press the MEAS key and select the "Digital Standards" softkey.
3. Select the required settings file and then "Load" (see
"To load predefined settings files" on page 211).
The instrument is adjusted to the stored settings for the selected standard and a measurement is started immediately.
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4. Press the RUN SINGLE key to stop the continuous measurement mode and start a defined number of measurements.
To load predefined settings files
1. In the "Meas" menu, select the "Digital Standards" softkey.
2. In the file selection dialog box, select the standard whose settings you want to load.
To change the path, press the arrow icons at the right end of the "Path" field and select the required folder from the file system.
3. Press the "Load" button.
The dialog box is closed and the instrument is adjusted to the stored settings for the selected standard.
To store settings as a standard file
2. In the "Meas" menu, select the "Digital Standards" softkey.
3. In the "File Name" field, enter the name of the standard for which you want to store settings.
To change the path, press the arrow icons at the right end of the "Path" field and select the required folder from the file system.
To insert a new folder, select the "New Folder" button and enter a name in the
"New Folder" dialog box.
4. Press the "Save" button.
The dialog box is closed and the current measurement settings are stored in a standard file.
To delete standard files
1. In the "Meas" menu, select the "Digital Standards" softkey.
2. In the "Manage VSA Standards" file selection dialog box, select the standard whose settings file you want to delete. Standards predefined by Rohde & Schwarz can also be deleted.
To change the path, press the arrow icons at the right end of the "Path" field and select the required folder from the file system.
3. Press the "Delete" button.
4. Confirm the message to avoid unintentionally deleting a standard.
The standard file is removed from the folder.
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To restore standard files
1. To restore the predefined standard files, do one of the following:
● In the "Meas" menu, select the "Digital Standards" softkey.
The "Manage VSA Standards" file selection dialog box is displayed.
● In the "Meas" menu, select the "Restore Factory Settings" softkey.
2. Select "Restore Standard Files".
The standards predefined by Rohde & Schwarz available at the time of delivery are restored to the Standards folder.
8.2 How to Perform Customized VSA Measurements
In addition to performing vector signal analysis strictly according to specific digital standards, you can configure the analysis settings for customized tasks. The general process for a typical VSA measurement is described here.
1. Press the MODE key and select the "VSA" application.
2. Select the "Overview" softkey to display the "Overview" for VSA.
3. Select the "Signal Description" button and configure the expected signal characteristics.
If the input data is largely known in advance, define files with the known data to
compare the measured data to (see chapter 8.2.3, "How to Manage Known Data
Files" , on page 218). This can improve demodulation significantly.
4. Select the "Input/Frontend" button to define the input signal's center frequency, amplitude and other basic settings.
5. Select the "Signal Capture" button and define how much and which data to capture:
(In MSRA mode, define the application data instead, see
MSRA Operating Mode" , on page 124).
● "Capture length": the duration or number of symbols to be captured
● "Sample rate": how many points are to be captured for each symbol
6. Optionally, select the "Trigger" tab and define a trigger for data acquisition, for example an external trigger to start capturing data only when a useful signal is transmitted.
(In MSRA mode, define a "Capture Offset" instead, see
MSRA Operating Mode" , on page 124).
7. For bursted signals, select the "Burst/Pattern" button and define the criteria to
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8. Select the "Cut Result Ranges" button and define which of the captured data is to be demodulated (see
chapter 8.2.4, "How to Define the Result Range" , on page 220).
9. Select the "Demodulation" button to configure and optimize the synchronization process.
10. Select the "Meas filter" button to select a different or user-defined measurement filter to improve the accuracy of the error vector (see
User-Defined Filters" , on page 213).
11. Select the "Evaluation Range" button to define which part of the demodulated data is to be evaluated and displayed.
12. Press the RUN SINGLE key to stop the continuous sweep and start a new sweep with the new configuration.
8.2.1 How to Select User-Defined Filters
The most frequently required measurement and TX filters required for vector signal analysis according to digital standards are provided by the R&S FPS VSA application.
However, you can also load user-defined filters.
To load a user measurement filter
1. In the "Overview", select the "Meas Filter" button.
2. In the "Meas Filter" tab of the "Demodulation & Measurement Filter "dialog box, select "Type": User.
3. Select "Load User Filter".
4. Load your .vaf file from the USB stick.
To load a user transmit (TX) filter
1. In the "Overview", select the "Signal Description" button.
2. In the "Modulation" tab of the "Signal Description" dialog box, select "Transmit Filter Type": User.
3. Select "Load User Filter".
4. Load your .vaf file from the USB stick.
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8.2.2 How to Perform Pattern Searches
To configure a pattern search
1. In the "Overview", select "Signal Description".
2. Select the "Signal Structure" tab.
3. Select the "Burst Signal" signal type.
4. Enable the "Pattern" option.
5. From the "Name" selection list, select a pattern that is assigned to the currently defined standard.
chapter 8.2.2.2, "How to Define a New Pattern" , on page 215.
7. Optionally, select the "Offset" option and enter the number of symbols in the signal to be ignored during the pattern search.
8. Close the "Signal Description" dialog box.
9. In the "Overview" dialog box, select "Burst / Pattern " and switch to the "Pattern
Search" tab.
10. Select "On" to enable the search.
To enable a search only if a pattern is part of the signal description, enable the
"Auto" option.
The results of the pattern search with the selected pattern on the current measurement data is displayed in the "Preview" area of the dialog box. Whether a pattern was detected or not is indicated in the "Information" area.
11. If necessary, adapt the I/Q correlation threshold. If bursts are not detected, reduce the threshold; if false bursts are detected, increase the threshold.
12. Optionally, enable the "Meas only if pattern symbols correct" option. In this case, measurement results are only displayed if a valid pattern has been detected.
13. Close the dialog box.
The selected pattern is used for a pattern search in the next measurement.
8.2.2.1
How To Assign Patterns to a Standard
Only patterns that are assigned to the currently selected VSA standard are available for the pattern search.
To add a predefined pattern to a standard
1. In the "Overview", select "Signal Description" and switch to the "Signal Structure" tab.
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2. Select "Pattern Config" to display the "Advanced Pattern Settings" dialog box.
3. In the list of "All Patterns", select the required pattern.
4. Select "Add to Standard".
The selected pattern is inserted in the list of "Standard Patterns".
5. Select the pattern to be used for the pattern search from the list of "Standard Patterns".
To remove a predefined pattern from a standard
1. In the "Overview", select "Signal Description" and switch to the "Signal Structure" tab.
2. Select "Pattern Config" to display the "Advanced Pattern Settings" dialog box.
3. Select the pattern from the list of "Standard Patterns".
4. Select "Remove from Standard".
The pattern is removed from the list of "Standard Patterns" and is no longer assigned to the current standard, but is still available for assignment from the list of
"All Patterns".
8.2.2.2
How to Define a New Pattern
1. In the "Overview", select "Signal Description" and switch to the "Signal Structure" tab.
2. Select "Pattern Config" to display the "Advanced Pattern Settings" dialog box.
3. Select the "New" button.
The pattern definition dialog box is displayed.
4. Define the following pattern settings:
Setting
Name
Description
Modulation order
Comment
Description
Pattern name that will be displayed in selection list
Optional description of the pattern which is displayed in the pattern details
Number of values each symbol can represent, e.g. 8 for 8-PSK
Optional comment for the pattern, displayed in the pattern details (kept for compatibility with FSQ)
5. Define the format used to define the individual symbols of the pattern.
6. Define the symbols of the pattern.
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How to Perform Customized VSA Measurements a) Select the symbol field you want to define.
If necessary, add a new symbol field by selecting "Add".
b) Enter a value using the keyboard. Depending on the "Modulation Order" <n>, the value can be in the range 0 to <n>-1.
c) Select the next symbol field, or insert a new one, and continue to define the other symbols. To scroll through the fields for long patterns, use the scrollbar beneath the input area. The number beneath the scrollbar at the right end indicates the sequential number of the last symbol field, the number in the center indicates the sequential number of the currently selected symbol field.
To remove a symbol field, select it and press "Remove".
7. Select "Save" to save the pattern under the specified name. The pattern is stored on the instrument as an xml file named <Name>.xml under
<Installation directory>\vsa\Pattern.
If you copy this file to another location, you can restore the pattern at a later time, e.g.
after deletion.
Example: Defining a pattern
Fig. 8-1: Pattern definition
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8.2.2.3
How to Manage Patterns
To change the display for the list of patterns
1. In the "Overview", select "Signal Description" and switch to the "Signal Structure" tab.
2. Select "Pattern Config" to display the "Advanced Pattern Settings" dialog box.
3. To display all available patterns, select "Show All".
To display all patterns that are compatible to the defined standard, select "Show
Compatible".
To display only patterns that contain a specific prefix, enter the "Prefix" in the edit field.
To edit a predefined pattern
1. In the "Overview", select "Signal Description" and switch to the "Signal Structure" tab.
2. Select "Pattern Config" to display the "Advanced Pattern Settings" dialog box.
3. Select the pattern from the list of "All Patterns".
4. Press "Edit Pattern".
5. Change the settings as required as described in chapter 8.2.2.2, "How to Define a
To delete a predefined pattern
1. In the "Overview", select "Signal Description" and switch to the "Signal Structure" tab.
2. Select "Pattern Config" to display the "Advanced Pattern Settings" dialog box.
3. Select the pattern from the list of "All Patterns".
4. Press "Delete Pattern".
The pattern is removed from the lists of available and assigned patterns and can no longer be assigned to any standard. Any existing assignments to other standards are removed, as well.
To restore predefined patterns
Default patterns provided by Rohde&Schwarz can be restored.
1. Press the MEAS key.
2. Select the "Restore Factory Settings" softkey.
3. Select the "Restore Pattern Files" softkey.
The patterns as defined by Rohde & Schwarz at the time of delivery are restored.
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Restoring user-defined patterns
User-defined patterns can only be restored if you have a copy of the pattern file created during creation. In this case, copy the file named <Patternname>.xml back to the installation directory of the VSA application under vsa/standards. After a preset or after performing certain operations (e.g. changing the modulation settings) the pattern will be included in the list of "All Patterns" again.
8.2.3 How to Manage Known Data Files
You can load xml files containing the possible sequences to the VSA application and use them to compare the measured data to. In particular, you can use known data for the following functions:
● Fine synchronization during the demodulation process (see
and
● Calculation of the Bit Error Rate (BER), see chapter 3.2.1, "Bit Error Rate (BER)" , on page 20
8.2.3.1
How to Load Known Data Files
Known Data files are loaded in the "Modulation & Signal Description" settings.
To load an existing Known Data file
1. In the "Overview", select "Signal Description".
2. Switch to the "Known Data" tab.
3. Activate the usage of a Known Data file by enabling the "Known Data" option. This enables the "Load Data File" function.
4. Select the "Load Data File" button.
A file selection dialog box is displayed.
5. Select the xml file which contains the possible data sequences of the input signal.
The file must comply with the syntax described in
Syntax Description" , on page 423.
The header information of the xml file is displayed in the dialog box.
Once a Known Data file has been loaded, the Bit Error Rate result display becomes available.
If the "Fine Synchronization" setting in the "Demodulation" dialog box is set to
"Auto" mode, the known data is also used for synchronization. Otherwise it can be selected manually. Defining a maximum symbol error rate for the known data in reference to the analyzed data avoids using a falsely selected or unsuitable file for
synchronization (see also "If SER ≤" on page 184.
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8.2.3.2
How to Create Known Data Files
You must create the Known Data files yourself according to the possible data sequences of the input signal. Use any xml editing tool you like, following the rules described in
chapter A.5, "Known Data File Syntax Description" , on page 423. Before loading the
file to the VSA application, make sure the syntax of your file is valid.
Auxiliary tool to create Known Data files
An auxiliary tool to create Known Data files from data that is already available in the
VSA application is provided on the instrument free of charge.
To create a Known Data file using the recording tool for sequences
1. Import or apply input data for which stable demodulation results are available to the
VSA application. If necessary, adapt the demodulation settings until the requested results are obtained.
2. Start the "R&S Recording Tool for Sequences" from the Windows task bar on the
R&S FPS, or execute the file RecordingToolforSequences.EXE from the installation directory on the instrument.
The "R&S Recording Tool for Sequences" window is displayed.
3. Start a measurement in the VSA application.
4. In the tool window, select "Run".
The tool records the demodulated data sequences. The following result information is provided by the tool during recording:
● Analyzed Sequences: number of data sequences analyzed since the tool was started
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● Different Sequences: number of unique sequences detected in the measured data
● Last New Sequence Found: time that has passed since the most recent unique sequence was detected
● Throughput: current data processing speed of the tool
Note that while the tool is running, the R&S FPS is set to remote mode, i.e. the manual interface is not available. As soon as the tool is closed, the remote mode is automatically deactivated.
5. When all known possible sequences have been detected, or when a significantly large amount of time has passed so as to assume no more sequences will be detected, stop the tool by selecting "Stop".
6. ● If the results are acceptable, select "Store for K70" to store a valid xml file with the recorded data sequences on the instrument.
A file selection dialog box is displayed in which you can select the storage location and file name.
You can also add an optional comment to the file.
● Otherwise, reset the tool to start a new recording, possibly after changing the demodulation settings or input data.
7. Close the tool window to return to normal operation of the VSA application.
8.2.4 How to Define the Result Range
You can define which part of the source signal is analyzed ("Result Range") with reference to the captured data, a detected burst or a detected pattern.
(For details on the functions see
chapter 5.8, "Result Range Configuration" , on page 173.)
1. In the "Overview", select "Range Settings".
2. Select the "Result Range" tab.
3. Define the "Result Length", i.e. the number of symbols from the result that are to be analyzed.
Note that when you use Known Data files as a reference, the "Result Length" specified here must be identical to the length of the specified symbol sequences in
the xml file (<ResultLength> element). See chapter 4.9, "Known Data Files -
Dependencies and Restrictions" , on page 123.
4. Define the "Reference" for the result range, i.e. the source to which the result will be aligned. The reference can be the captured data, a detected burst or a detected pattern.
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5. Define the "Alignment" of the result range to the reference source, i.e. whether the result starts at the beginning of the reference source, ends with the reference source, or is centered with the reference source.
6. Optionally, define an offset of the result range to the reference source, e.g. to ignore the first few symbols of the captured data.
7. Optionally, define the number of the symbol which marks the beginning of the reference source to change the scaling of the x-axis. This offset is added to the one defined for the signal description.
Example: Defining the result range
In
, a result range will be defined for the first 100 symbols of the capture buffer, starting at the second symbol, which has the symbol number 1 (the capture buffer starts at symbol number 1, the first symbol to be displayed is the second symbol due to the offset: 1+1=2).
Fig. 8-2: Example: Defining the Result Range
The result range is indicated by a green bar along the time axis in capture buffer result displays, see
chapter 4.6, "Measurement Ranges" , on page 116.
8.3 How to Analyze the Measured Data
Once the data has been stored in the capture buffer, the results can be analyzed in numerous ways. The following tasks are meant to make you familiar with the most
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How to Analyze the Measured Data common VSA application features. For a description of all analysis functions and set-
tings see chapter 6, "Analysis" , on page 190.
1. Press the MEAS CONFIG key to display the VSA menu.
2. Select the "Display Config" button in the "Overview" or the "Display Config" softkey and select the data sources for evaluation that are of interest to you (see
chapter 6.5, "Display and Window Configuration" , on page 201).
Arrange them on the display to suit your preferences.
For each data source, a window with the default result type for that data source is displayed.
3. Exit the SmartGrid mode.
4. Select the "Window Config" softkey to change the result types and other display settings for the selected window. To change the settings in other windows, select a different window from the "Specifics for" list in the "Window Config" dialog box.
5. Select the "Overview" softkey to display the "Overview".
Enable the "Specifics for" option to access the analysis functions for the selected window.
6. Select the "Analysis" button in the "Overview" to configure special analysis settings for the individual result displays, for example:
● Configure markers and delta markers to determine deviations and offsets within the results, e.g. when comparing errors or peaks.
● Configure the trace to display the average over a series of measurements. If necessary, increase the "Statistics Count" defined in the "Sweep" menu.
7. Press the SWEEP key and select the "Selected Result Rng" softkey to select a specific burst to be evaluated.
The result displays are updated to show the results for the selected burst.
Tip: You can use a capture buffer display to navigate through the available result ranges, and analyze the individual result ranges in another window. The currently displayed result range is indicated by a blue bar in the capture buffer display.
8. Optionally, zoom into a diagram to enlarge an area of the displayed data.
9. Optionally, change the display scaling for diagrams (see
Change the Display Scaling" , on page 223).
11. Optionally, export the trace data of the measured signal to a file (see chapter 8.3.3,
"How to Export the Trace Data to a File" , on page 226).
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8.3.1 How to Change the Display Scaling
Depending on the type of display (time, spectrum or statistics), various scaling functions are available to adapt the result display to the current data.
8.3.1.1
How to Scale Time and Spectrum Diagrams
The range of the displayed y-axis for time and spectral diagrams can be defined in the following ways:
● manually, by defining the range size, reference values and positions
● automatically, according to the current results
To define the scaling manually using a reference point
With this method, you define a reference value and a position at which this value is to be displayed on the y-axis.
1. Focus the result window.
2. Select "AMPT > YScale Config > Y-Axis Reference Value".
3. Enter a reference value for the y-axis in the current unit.
4. Select "AMPT > YScale Config > Y-Axis Reference Position" .
5. Enter the position at which this value is to be displayed on the y-axis. The position is a percentage of the entire length, where 100 % refers to the top edge.
6. Select "AMPT > YScale Config > Y-Axis Range".
Example:
If you want the to analyze errors greater than 95%, you can define the y-axis range as
5 % and position the y-axis to start at 95%. To do so, enter the reference value 95 % and the reference position 0%.
Fig. 8-3: Defining the y-axis scaling using a reference point
To define the scaling automatically
1. Focus the result window.
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2. Select "AMPT > Y-Axis Auto Scale".
The y-axis is adapted to display the current results optimally (only once, not dynamically).
8.3.1.2
How to Scale Statistics Diagrams
Statistic diagrams show the distribution (i.e. probabilities of occurrence) of the values as a set of bars. You can define the number of bars to be displayed, i.e. the granularity of classifications. Additionally, you can specify whether absolute or percentage values are displayed. For statistics measurements, both the x-axis and the y-axis can be scaled to optimize the display.
The range of the displayed x-axis for statistics diagrams can be defined in the following ways:
● manually, by defining reference values and positions
● automatically, according to the current results
The range of the displayed y-axis can be defined in the following ways:
● manually, by defining the minimum and maximum values to be displayed
● automatically, according to the current results
After changing the scaling you can restore the default settings.
To define the number of bars
1. Focus the result window.
2. Select "AMPT > XScale Config > X-Axis Quantize".
3. Enter the number of bars to be displayed.
The diagram is adapted to display the specified number of bars.
To define the x-axis scaling manually using a reference point and divisions
With this method, you define a reference value on the x-axis to be displayed at the "Ref
Position" of the y-axis. (The reference value is determined internally according to the displayed data and cannot be changed. The beginning of the diagram is at the position
0%, the end is at 100%.) Additionally, you define the range to be displayed in each of the 10 divisions of the display, which determines the total range to be displayed on the x-axis.
1. Focus the result window.
2. Select "AMPT > Scale Config > Reference Value".
3. Enter a reference value on the x axis in the current unit.
4. Define the range to be displayed per division (total range/10).
The x-axis is adapted so that it displays the defined range, with the reference value at the specified position.
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Example:
If you want to analyze the probabilities of occurrence for errors greater than 95 %, enter the reference value 95 %.
Fig. 8-4: Defining the x-axis scaling using a reference point
To define the x-axis scaling automatically
1. Focus the result window.
2. Select "AMPT > XScale Config > Auto Scale".
The x-axis is adapted to display the current results optimally (only once, not dynamically).
To define the y-axis range manually
With this method, you define the upper and lower limits of the displayed probability range. Values on the y-axis are normalized which means that the maximum value is
1.0. If the y-axis has logarithmic scale, the distance between max and min value must be at least one decade.
1. Focus the result window.
2. Select "AMPT > YScale Config > Y-Axis Min Value".
3. Enter the lower limit in the current unit.
4. Select "AMPT > YScale Config > Y-Axis Max Value".
5. Enter the upper limit in the current unit.
The y-axis is adapted to display the specified range. Probabilities of occurrence located outside the display area are applied to the bars at the left or right borders of the display.
8.3.2 How to Check Limits for Modulation Accuracy
The results of a modulation accuracy measurement can be checked for violation of defined limits automatically. If limit check is activated and the measured values exceed the limits, those values are indicated in red in the result summary table. If limit check is activated and no values exceed the limits, the checked values are indicated in green.
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For details on the limit check functions and settings see
chapter 6.4, "Modulation Accuracy Limit Lines" , on page 199.
To define a limit check
1. Configure a measurement with "Modulation Accuracy" as the "Source" (see
chapter 6.5, "Display and Window Configuration" , on page 201).
2. Press the LINES key.
3. Press the "ModAcc Limits Config" softkey in the "Limits" menu.
4. In the "Current" tab, define limits that the current value should not exceed for any or all of the result types.
Note: the limits for the current value are automatically also defined for the peak value and vice versa. However, the limit check can be enabled individually for current or peak values.
5. Enable the "Check" option for each result type to be included in the limit check.
6. If necessary, define limits and enable the limit check for the mean values of the different result types on the "Mean" tab.
7. If necessary, enable the limit check for the peak values of the different result types on the "Peak" tab.
8. To reset the limits to their default values, press "Set to Default".
9. Enable the "Limit Checking On" option, or press the "ModAcc Limits On" softkey in the "Limits" menu.
The limit check is performed immediately on the current modulation accuracy measurement results and for all subsequent measurements until it is disabled. The results of the limit check are indicated by red or green values in the result summary.
8.3.3 How to Export the Trace Data to a File
The measured data can be stored to an ASCII file, either as raw data (directly from the capture buffer) or as displayed in the diagrams (evaluated trace data). Optionally, a header can be included with additional information on the used measurement settings.
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1. Press the TRACE key and select the "Trace Export Config" softkey.
2. Define which type of data to export (raw or trace). By default, trace data is exported.
3. Optionally, enable the header information to be included.
4. To export the traces in all windows, select "Export Trace to ASCII File for all Windows".
To export the traces only for the currently selected window, select "Export Trace to ASCII File for Specific Window". To export the data from another window, select it from the "Specifics for" list, then export again.
In either case, all traces of the selected window(s) are exported.
5. Define a file name and storage location and select "OK".
The data is stored in a file and can be analyzed in an external application.
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Connecting the Transmitter and Analyzer
9 Measurement Examples
Some sample measurements for the digital GSM and EDGE standards provide a quick introduction to typical vector analyzer measurements. The individual measurements are in logical order and are meant to familiarize you gradually with the measurements required of general vector signal analysis.
The following equipment is required in addition to the R&S FPS with option R&S FPS-
K70:
● 1 test transmitter (GSM-compatible for Measurement 2), preferably R&S
SMW200A (1412.0000.02), with the digital standard option GSM/EDGE (order number 1413.3684.02)
● 1 RF cable with 2 male N connectors
● 2 power cables
Transmitter operation is only described as far as required for performing the measurements. For more details on the measurements, refer to the test transmitter documentation.
9.1 Connecting the Transmitter and Analyzer
In order to perform measurements with the R&S FPS-K70, you require a test transmit-
ter to emulate a DUT. For Measurement Example 2: Burst GSM EDGE Signals , the
test transmitter needs to be GSM-compatible.
Connect the RF output of the R&S SMW200A with the RF input of the R&S FPS.
9.2 Measurement Example 1: Continuous QPSK Signal
In this measurement example a continuous QPSK (Quadrature Phase Shift Keying) signal will be measured and evaluated. QPSK is used in several standards such as
DVB-S2, APCO25, WCDMA, CDMA2000, etc. For the description (characterization) of a continuous QPSK signal, the following parameters are the most important:
● Carrier Frequency
● Level
● Symbol Rate
● Transmit Filter
9.2.1 Transmitter Settings
This section summarizes the necessary transmitter settings. It contains a list of the parameters and step-by-step instructions for the R&S SMW200A. If you are interested in a more detailed description or background information, refer to the user manual of
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Measurement Example 1: Continuous QPSK Signal the R&S SMW200A, which can be downloaded from the Rohde&Schwarz website: www.rohde-schwarz.com/downloads/manuals/smw200A.html
.
Frequency
Level
Modulation
Symbol Rate
Filter
1 GHz
0 dBm
QPSK
1 Msym/s
Root Raised Cosine with Roll-Off 0.35
To define the settings for the R&S SMW200A
1. Press the PRESET key to start from a defined state.
2. Press the FREQ key and enter 1 GHz.
3. Press the LEVEL key and enter 0 dBm.
4. Press the DIAGRAM key.
5. Select the "Baseband A" block.
6. Select "Custom Digital Mod...".
7. In the "General" tab, define the following settings:
Fig. 9-1: R&S SMW200A: Custom Digital Modulation Dialog a) Toggle the "State" to "On".
b) Enter the "Symbol Rate": 1 MHz.
c) Set the "Coding" to "Off".
8. In the "Modulation" tab, select "Modulation Type": "PSK" > "QPSK".
9. In the "Filter" tab, select the "Filter":"Root Cosine".
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Measurement Example 1: Continuous QPSK Signal
10. Press the RF ON/OFF key to switch the RF transmission on.
9.2.2 Analyzer Settings
This section helps you get your first valid measurement. It starts with step-by-step instructions and continues with a more detailed description of further functionality.
Frequency
Ref Level
Modulation
Symbol Rate
Tx Filter
1 GHz
4 dBm
QPSK
1 MHz
Root Raised Cosine with Alpha BT 0.35
To define the settings on the R&S FPS
1. Press the PRESET key to start from a defined state.
2. Press the FREQ key and enter 1 GHz.
3. Press the AMPT key, and enter 4 dBm as the reference level. This corresponds approximately to the peak envelope power of the signal.
4. Start the VSA application by pressing the MODE key and then selecting "VSA".
5. Select the "Overview" softkey to display the "Overview" for VSA.
6. Select the "Signal Description" button and configure the expected signal characteristics.
a) In the "Modulation Settings" section, ensure that the "Type" is "PSK" and that the "Order" is "QPSK". The "Mapping" defines the mapping of the bits to the
QPSK symbols. It is relevant if you are interested in a bit stream measurement but does not affect the other measurement results. Hence, you do not need to change it here.
b) Enter the "Symbol Rate" 1 MHz.
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Measurement Example 1: Continuous QPSK Signal c) In the "Transmit Filter" section, select "RRC" as "Type" and enter the
"Alpha/BT" value 0.35. In the preview area of the dialog you should then see a
non-distorted QPSK constellation diagram, as shown in figure 9-2 .
Fig. 9-2: QPSK signal with RRC transmit filter
7. Close all open dialog boxes. By default, four measurement windows showing different measurement results are displayed.
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Measurement Example 1: Continuous QPSK Signal
Fig. 9-3: Default window layout for Measurement Example 1
9.2.3 Changing the Display Configuration
1. To change the window layout, i.e. the display configuration, do one of the following:
● Select the "Display Config" softkey in the main VSA menu.
● Select the "Display Configuration" block in the "Overview" (only if "Specifics for" option is disabled).
●
Select the "SmartGrid" icon from the toolbar.
2. Replace window 1 by an eye diagram of the inphase component of the measurement signal.
a) Select the "Meas & Ref" data source from the SmartGrid selection bar and drag it over window 1.
b)
Close the SmartGrid mode by selecting the "Close" icon at the top right corner of the toolbar.
c) Select the "Window Config" softkey.
d) Select the result type: "Eye Diagram Real (I)".
3. Close the dialog to take a look at your new display configuration.
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Measurement Example 1: Continuous QPSK Signal
9.2.4 Navigating Through the Capture Buffer
Using the R&S FPS VSA application you can navigate through the capture buffer, i.e.
control which part of the capture buffer is currently analyzed. (Note: In the Spectrum application, this functionality is referred to as "gating".)
1. In the measurement display, take a closer look at window 3 (magnitude of the capture buffer). The green bar shows how far the current measurement has already proceeded, i.e. how much of the signal has been evaluated.
2. Press the RUN SINGLE key.
Since the signal you are currently analyzing is continuous (as opposed to containing bursts), the entire capture buffer is analyzed, and hence will be marked with the green bar. The last evaluated result range (i.e. the currently evaluated result range at the time the measurement stopped) is highlighted in blue.
3. To go back to a previously evaluated result range within the same capture buffer, press the SWEEP key and then the "Select Result Rng" softkey. By selecting different result ranges (for example using the rotary knob), you can move the highlighted blue area through the capture buffer and choose your currently demodulated result range.
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Measurement Example 1: Continuous QPSK Signal
The results for this range are displayed in the "Current" column in the Result Summary, in the eye diagram and in the symbol table.
Note: Generally, all Clear/Write traces and the are affected by this selection.
9.2.5 Averaging Several Evaluations
By default, all measurement windows are displayed with a single trace, which is the
Clear/Write trace. This trace displays the result of the current evaluation, i.e. the high-
lighted blue area from the example in chapter 9.2.4, "Navigating Through the Capture
Buffer" , on page 233. However, for most real-world measurement tasks, you need to
obtain a result that is averaged over a certain number of evaluations, or a worst-case result of a certain number of evaluations. This section explains how to achieve this.
To evaluate EVM vs. Time
1. Configure window 1 such that it displays the EVM versus time measurement
(Source: "Error Vector", Result Type: "EVM", see
2. To display the trace averaged over several measurements, or the maximum hold trace over several measurements, press the TRACE key.
3. Add further traces by pressing the TRACE key and then either using the "Trace
2/3..." or the "Trace Config" softkeys.
Set the second trace to "Average" and the third trace to "Max Hold".
Note that the configured traces appear in the window title.
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Measurement Example 2: Burst GSM EDGE Signals
Fig. 9-4: Several traces in one window
4. Press RUN SINGLE again.
The current capture buffer is evaluated for this trace setup. In the channel information bar you can see the number of completed evaluations ("Stat Count").
5. To change the number of evaluations, press the SWEEP key and select "Statistic
Count Config".
Select "Manual" and enter the desired number of evaluations, e.g. 12. When you press RUN SINGLE, the VSA application will capture I/Q data until 12 evaluations are completed.
9.3 Measurement Example 2: Burst GSM EDGE Signals
In this measurement example a bursted GSM EDGE signal will be measured and evaluated. The goal of this section is to familiarize you with the VSA application features that are relevant specifically for the analysis of bursted signals.
9.3.1 Transmitter Settings
This section summarizes the necessary transmitter settings. It contains a list of the parameters and step-by-step instructions for the R&S SMW200A. If you are interested in a more detailed description or background information, refer to the user manual of the R&S SMW200A, which can be downloaded from the Rohde & Schwarz website: www.rohde-schwarz.com/downloads/manuals/smw200A.html
.
Frequency
Level
Standard
1 GHz
0 dBm
GSM EDGE Burst with normal symbol rate
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Measurement Example 2: Burst GSM EDGE Signals
To define the settings for the R&S SMW200A
1. Press the PRESET key to start from a defined state.
2. Press the FREQ key and enter 1 GHz.
3. Press the LEVEL key and enter 0 dBm.
4. To define the standard: a) Select the "Baseband A" block.
b) Under "TSMA standards", select "GSM/EDGE...".
5. To configure the burst type in the "GSM/EDGE A" dialog box: a) In the "Framed (Single) Configuration" tab, highlight the first slot in the frame diagram.
Fig. 9-5: R&S SMW200A: GSM/EDGE frame configuration settings
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Measurement Example 2: Burst GSM EDGE Signals b) In the "GSM/EDGE A: Burst@Slot0" dialog box, select the "Burst Type": "Normal (8PSK / EDGE)".
c) Close the "GSM/EDGE: Burst@Slot0" dialog box.
6. In the "General" tab, toggle the "State" to "On" to switch the modulation on.
7. Close the "GSM/EDGE A" dialog box.
8. Select the "RF A" signal output to switch the RF transmission on.
9.3.2 Analyzer Settings
This section helps you get your first valid measurement with a bursted signal. It starts with step-by-step instructions and continues with a more detailed description of further functionality.
Frequency
Ref Level
Standard
1 GHz
4 dBm
GSM 8PSK EDGE
To define the settings on the R&S FPS
1. Press the PRESET key to start from a defined state.
2. Press the FREQ key and enter 1 GHz.
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Measurement Example 2: Burst GSM EDGE Signals
3. Press the AMPT key, and enter 4 dBm as the reference level. This corresponds approximately to the peak envelope power of the signal.
4. Start the VSA application by pressing the MODE key and then selecting "VSA".
5. Select the "Overview" softkey to display the "Overview" for VSA.
6. Press the MEAS key, then select the "Digital Standards" softkey.
7. From the file selection list, select the GSM folder and then the file EDGE_8PSK.
Select "Load".
Predefined settings corresponding to the selected standard are loaded. The VSA application should show good measurement results.
Fig. 9-6: Default display configuration for GSM 8PSK EDGE
8. In window 3, you see the currently evaluated burst marked with a green bar.
To include more bursts in the display you need to increase the capture length.
a) Press the MEAS CONFIG key and then the "Overview" softkey.
b) Select "Signal Capture".
c) Increase the "Capture Length", e.g. to 10000 symbols.
In the preview area of the dialog box you see that more bursts are now contained in the capture buffer. They are all marked with a green bar, meaning that they are all evaluated.
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Measurement Example 2: Burst GSM EDGE Signals
Fig. 9-7: Preview of capture buffer
9.3.3 Navigating Through the Capture Buffer
This example describes how to navigate through the capture buffer for a continuous signal. This navigation feature is especially important for bursted signals. Therefore, we provide a further navigation example for the GSM EDGE signal.
1. In order to see more details in the capture buffer, close window 4.
a) Press the "Display Config" softkey, or the "Display Configuration" button in the
"Overview".
b) Select the "Delete" icon for window 4.
c)
Close the SmartGrid mode by selecting the "Close" icon at the top right corner of the toolbar.
2. Press the RUN SINGLE key.
3. In the "EVM vs. Time" display (window 1), add a maximum hold trace by pressing the TRACE key and then selecting the "Trace Config" softkey (see
"Averaging Several Evaluations" , on page 234).
4. Re-evaluate the whole capture buffer by pressing the SWEEP key and then the
"Refresh" softkey.
5. Use the "Select Result Rng" softkey to navigate through your capture buffer. Thus, you can determine which peak was caused by which burst.
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Measurement Example 2: Burst GSM EDGE Signals
Fig. 9-8: Navigation through the capture buffer
9.3.4 Evaluating the Rising and Falling Edges
The "Result Length" is the number of symbols that are to be demodulated and analyzed together. In most common applications, only the parts of the capture buffer containing the bursts need to be analyzed. Hence, for bursted signals the "Result Length" usually coincides with the burst length. However, there are certain scenarios where the rising and falling edge of a burst are also of interest, e.g. checking the power ramping of the device under test. For this measurement task, it is useful to choose a "Result
Length" that exceeds the burst length.
1. In order to include the rising and falling edges of the bursts in the EVM vs Time display (window 1), you need to increase the "Result Length".
In the "Overview", select "Cut Result Range" and increase the "Result Length" to
200 symbols.
2. To evaluate the rising and falling edges further, display the absolute magnitude values of the measured signal in window 4 (Source: "Meas&Ref Signal", Result type:
"Magnitude Absolute", see
chapter 9.2.3, "Changing the Display Configuration" , on page 232).
3. Press RUN SINGLE.
The rising and falling edges of the burst in the selected result range are displayed in window 4. You could now add an average trace to evaluate the rising and falling edges further.
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Measurement Example 2: Burst GSM EDGE Signals
Fig. 9-9: Result range that exceeds the burst length
9.3.5 Setting the Evaluation Range
In some scenarios, such as in
Evaluating the Rising and Falling Edges
, the result range contains symbols that are not supposed to be considered for the EVM or other calculated parameters that are displayed in the Result Summary. Thus, you would not include them in the evaluation range.
To change the evaluated data
1. Start from the configuration described in
chapter 9.3.4, "Evaluating the Rising and
2. Display the I/Q constellation diagram of the signal in window 1(Source: "Meas&Ref
Signal", Result type: "Constellation I/Q", see
chapter 9.2.3, "Changing the Display
Configuration" , on page 232).
A clear 8PSK constellation is displayed.
Fig. 9-10: Evaluation lines properly adjusted
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Measurement Example 2: Burst GSM EDGE Signals
3. In order to understand the effect of an incorrectly set evaluation range, change the evaluation range to include the entire result range.
a) In the "Overview", select "Evaluation Range".
b) Enable the "Entire Result Range" option.
The displayed constellation diagram is no longer clear, it contains additional points.
This is due to the fact that the constellation diagram now displays symbol instants that are beyond the burst.
Fig. 9-11: Evaluation lines not properly adjusted
All measurement windows that consider the evaluation range are marked with two small red lines in the title bar.
9.3.6 Comparing the Measurement Signal to the Reference Signal
You have seen that it is possible to add different traces such as maximum hold or average to each window. When evaluating the measurement signal it is also possible to display the ideal reference signal as an additional trace. This can be a significant help when troubleshooting, since it allows for an immediate comparison.
1. Start from the configuration described in
chapter 9.3.4, "Evaluating the Rising and
2. Select window 4 to set the focus on it.
3. Press the TRACE key and then the "Trace 2" softkey.
4. Select "Clear Write" as the "Trace Mode" and "Evaluation: Ref". This adds a second trace to your result display. This trace is the ideal reference signal that can
now be compared to the measurement signal (see figure 9-12
).
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Measurement Example 2: Burst GSM EDGE Signals
5. To view the traces in more detail, enlarge the window using the "Split/Maximize" key ( ), and zoom into the display using the icon in the toolbar (see the dot-
).
Fig. 9-12: Zooming
Now you can compare the measured and the ideal reference signal.
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R&S ® FPS-K70 Optimizing and Troubleshooting the Measurement
Flow Chart for Troubleshooting
10 Optimizing and Troubleshooting the Measurement
If the results do not meet your expectations, the following tips may help you optimize or troubleshoot the measurement.
10.1 Flow Chart for Troubleshooting
If you experience a concrete measurement problem, you might want to try solving it with the help of the flow chart.
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Flow Chart for Troubleshooting
Troubleshooting Overview
Press Preset
(in order to start from a known state)
Check the following parameters (at the DUT and the K70):
- Center frequency
- Reference Level, overload
- Symbol rate
- Transmit filter
- Modulation Type
- Sideband inversion (Swap IQ)
Demodulation Failed
Indications are (e.g.):
- Sync Failed/Unstable Message in the Status Bar
- The EVM is really bad
- The measurement I/Q Constellation does not look at all like a constellation
Check the measurement:
Mag(CapBuffer)
To make sure you realize once the problem is fixed, switch on the EVM trace and keep an eye on it.
1
Is the colored bar (="Result Range") in a range where you expect the signal to have the set modulation ?
yes yes
Is your signal bursted?
no Try to increase "Run-In" and
"Run-Out" in the "Signal
Description" > "Signal
Structure" dialog
Refer to the "Error Messages" section in the manual
This can be problematic. If you have a pattern, you can try to use it for synchronization, i.e. use the setting "Coarse Synchronization: Pattern"
("Demodulations - Advanced" dialog).
no
Can you increase the length
of your "Result Range"? Is your burst possibly larger?
yes
Increase the "Result Range" to at least 8xModulation
Order.
Go back to 1 yes
Is "Sync prefers more valid symbols" displayed in the status bar?
no no
Do you transmit uncorrelated random bits on the physical level?
yes no
Is your "Result Range" larger than ~8xModulation Order, e.g.
8x4=32 for QPSK?
yes
Try to switch on the equalizer in the “Demodulation“ dialog and compensate for the channel
Try to compensate for the symbol rate error in the
“Demodulation“ dialog no
See part 2
Hard to find the origin of the problem.
It might be that:
- Your DUT suffers from massive impairments.
- Your DUT suffers from a severe symbol rate error.
- The adjacent channel power is very high.
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Explanation of Error Messages no
From 1 yes
Is your signal bursted?
yes no
Make sure your "Signal Type" in the "Signal Description" dialog is a "Burst Signal"
Does your signal contain a pattern?
yes
Is this pattern relevant, e.g.
to align your result to the pattern or to check whether the pattern is transmitted correctly?
yes
Make sure the pattern is indicated in the "Signal
Description" dialog no
Make sure the burst search is switched on in the "Burst
Search" dialog
Make sure the pattern search is switched on.
no
Does your signal consist of ranges with different modulation types?
yes
Use the "Offset" and "Result Length" parameters in the "Result Range" dialog to move your result range to the desired point in the capture buffer.
no section in the manual
Is "Burst Not Found" displayed in the status bar?
no
Make sure your
"Result Range Alignment" reference is "Burst".
("Range Settings" dialog)
Refer to the "Error Messages"
Do you see a "Pattern Not
Found" Message?
no
Make sure your
"Result Range Alignment" reference is "Pattern Waveform".
(Range Setting Dialog) yes
Go back to 1
Use an external trigger and an appropriate trigger offset.
Go back to
Refer to the "Error Messages" section in the manual
1
10.2 Explanation of Error Messages
The following section describes error messages and possible causes.
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Explanation of Error Messages
Message: 'Burst Not Found'
The "Burst Not Found" error message can have several causes:
● Burst search is active, but the signal is not bursted
Fig. 10-1: Example for active burst search with continuous signal
Solution: Select "Continuous Signal" as the signal type.
For more information, see
–
● Signal is bursted, but bursts have not been captured completely
The burst search can only find bursts that start and end within the capture buffer. It ignores bursts that are cut off.
Fig. 10-2: Example for incomplete burst capture
Solution: Change the trigger settings and/or enlarge the capture length.
For more information, see
–
chapter 5.6, "Signal Capture" , on page 154
● The current measurement is being performed on a burst that has not been captured completely.
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Fig. 10-3: Example for measurement on incomplete burst capture
Fig. 10-4: Example for measurement on complete burst capture
Solution:
Change the trigger settings or increase the result length.
Note, however, that in this case, the results are actually correct and the message can be ignored.
● The settings do not match the signal
In order to allow you to select certain bursts, the burst search only searches for bursts that have a length between "Min Length" and "Max Length" (plus a tolerance that you can set in the "Burst Search" Dialog). In case the burst is, e.g. shorter than the "Burst Min Length", the burst search fails.
Fig. 10-5: Example for a failed burst search due too a burst that is too short
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Explanation of Error Messages
Solution: try one of the following:
– Switch on the Magnitude (Capture Buffer) result display. Move a marker to the start of the burst. Move a delta marker to the end of the burst and compare the burst length to the settings in the "Signal Description" dialog.
– Increase the search tolerance in the "Burst Search" dialog. Keep an eye on the green/red field. If the burst search succeeds, you can see the length of the found bursts.
– Set the minimum burst length to 50 and the maximum burst length to 5000.
For more information, see:
–
–
"Burst Configuration" on page 166
● The signal is highly distorted and/or has modulation noise
One possibility to enhance the robustness of the burst search is to increase the minimum gap length. If the bursts within your capture buffer are not closely spaced, it makes sense to increase the value of this parameter.
Fig. 10-6: Example for adjusting the minimum gap length
For more information, see
● The pattern search is switched on, fails and the alignment is with reference to the pattern.
In case the pattern search is switched on and the reference for the alignment is the pattern (and not the burst), a non-detected pattern causes the result range to be positioned at the beginning of the capture buffer. Hence, if a the burst does not start right at the beginning of the capture buffer, you will see a "Burst Not Found"
Message.
Solution:
– Refer to
"Message: 'Pattern Not Found'" on page 249
– Switch the pattern search off.
– Choose "Burst" as the reference for the result range alignment.
Message: 'Pattern Not Found'
The "Pattern Not Found" error message can have several causes:
● The burst search has failed
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Explanation of Error Messages
If burst and pattern search are active, the application looks for patterns only within the found bursts. Hence, in case the burst search fails, the pattern search will also fail.
Solution: Try one of the following:
– Make sure the burst search is successful.
– Deactivate the burst search but keep the pattern search active.
For more information, see
–
"Message: 'Burst Not Found'" on page 247
chapter 5.7.1, "Burst Search" , on page 164
● The offset of the pattern within the burst is incorrectly set
It is possible to set a pattern offset to speed up the pattern search. The offset of the pattern would be the offset of the pattern start with respect to the start of the useful part of the burst. However, if the entered offset is not correct (within about 4 symbols of tolerance), the pattern will not be found.
Fig. 10-7: GSM EDGE burst; Pattern is actually located in the middle of the burst. The correct value for "Offset" here would be 58.
Solution: Try one of the following:
– Remove the offset ('unknown').
– Enter the correct offset (within about 4 symbols of tolerance).
For more information, see
–
● The specified pattern does not coincide with the pattern in your signal:
In the R&S FSQ-K70 it is possible to search for multiple patterns at the same time.
For example, in a GSM measurement, the capture buffer can be checked for all
TSCs simultaneously. This is not possible in the R&S FPS-K70.
Solution:
Make sure that the correct pattern is specified in the "Signal Description" dialog.
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Explanation of Error Messages
For more information, see
–
chapter 5.4, "Signal Description" , on page 134
Message: 'Result Alignment Failed'
The result range alignment is not possible for the patricular capture buffer. The result range needs I/Q data that has not been captured.
Fig. 10-8: Example for failed alignment
In this windowshot, the alignment of the long result range to the burst center is not possible because there are not enough samples in the capture buffer before the burst starts. In this scenario, the trigger settings should be changed such that the burst is in the middle of the capture buffer.
Solution: Change the trigger settings and/or enlarge the capture length.
For more information, see:
●
chapter 5.6, "Signal Capture" , on page 154
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Explanation of Error Messages
Message: 'Pattern Search On, But No Pattern Selected'
Fig. 10-9: The red circle shows the place where you can specify a pattern
Solution: Select an existing pattern (or create a new pattern) that you expect to be within the signal.
For more information, see
●
"Pattern Settings" on page 140
chapter 8.2.2, "How to Perform Pattern Searches" , on page 214
Message: 'Pattern Not (Entirely) Within Result Range
A pattern can only be found, if it is entirely within the result range. Therefore, this error message always occurs with a "Pattern Not Found" error.
Solution: Choose the pattern as reference of your result range alignment. Then, the pattern will be forcefully part of your result range and the pattern search can succeed.
For more information, see
●
chapter 5.8, "Result Range Configuration" , on page 173
●
chapter 8.2.4, "How to Define the Result Range" , on page 220
Message: 'Short Pattern: Pattern Search Might Fail'
The R&S FPS performs the pattern search in two stages.
● Stage 1 involves the generation of an I/Q pattern waveform by modulating the pattern symbol sequence. The I/Q pattern is then correlated with the measured signal.
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Explanation of Error Messages
At positions where the correlation metric exceeds the "I/Q Correlation Threshold" the I/Q pattern is found.
● Stage 2 demodulates the measured signal at the I/Q pattern location and the transmitted symbols are checked for correctness against the pattern symbol sequence.
In case of a very short pattern, i.e. a pattern length in the order of the inter-symbol interference (ISI) duration, a number of issues can arise:
● False positive
The I/Q pattern is found at positions where the transmitted symbols differ from the pattern symbols.
Solution: Try one of the following:
– Activate "Meas only if Pattern Symbols Correct".
– Increase the "I/Q Correlation Threshold"
(see chapter 5.7.2, "Pattern Search" , on page 166).
● False negative
The I/Q pattern search misses a position where transmitted symbols match the pattern symbols.
Solution:
– Decrease the "I/Q Correlation Threshold"
(see chapter 5.7.2, "Pattern Search" , on page 166).
In case of bursted signals the pattern search finds only the first occurrence of the
I/Q pattern within each burst. If a false positive occurs in this situation (cf. case 1.) the use of "Meas only if pattern symbols correct" will not provide a satisfactory solution.
In this case do the following:
– Increase the "I/Q Correlation Threshold".
– Specify the expected position of the pattern within the burst by adjusting the
"Offset" parameter.
Message: 'Sync Prefers More Valid Symbols'
Note: Note that this message does not necessarily indicate a problem. Its purpose is to inform you that you might have the opportunity to get a more stable demodulation and/or better measurement results by improving your setup.
Synchronization in the VSA application is performed in two stages: coarse synchronization that precedes the reference signal generation and fine synchronization based on the reference signal.
● The coarse synchronization stage can work data-aided (i.e. based on a known pattern) or non-data-aided (i.e. based on the unknown data symbols). The default is a non-data-aided coarse synchronization. In the case that a pattern is part of signal, the user can switch to data-aided synchronization.
● The fine synchronization stage always works data-aided.
'Sync Prefers More Valid Symbols' indicates that one of the synchronization stages has too few symbols to ensure that the synchronization is robust.
The message is given if
● Coarse Synchronization = Non-Data-Aided (User Pattern for Sync = Off):
Estimation range shorter than 40 symbols
(see
chapter 4.5.1.2, "Estimation" , on page 101)
● Fine Synchronization:
Estimation range shorter than 10 symbols
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Explanation of Error Messages
(see
chapter 4.5.1.2, "Estimation" , on page 101)
Solution:
● If the signal contains a pattern, set "Coarse Synchronization: Pattern".
(see
"Coarse Synchronization" on page 183).
Example: measurement of a GSM EDGE pattern that has a length of 26 symbols.
Fig. 10-10: User Pattern for Sync = Off
Fig. 10-11: User Pattern for Sync = On
● Choose a longer "Result Range".
● If the signal is bursted and the bursts are short:
– Make sure your "Result Range" comprises the entire burst.
– Make sure that "Run-In/Out" is not chosen too large, since the "Run-In/Out" ranges are excluded from the synchronization.
● If the signal is bursted and contains a pattern:
Only switch off the burst search if absolutely necessary. If you need to switch it off, align your "Result Range" to the pattern, make sure it does not exceed the burst ramps and choose "Continuous Signal" as the "Signal Type" in the "Signal Description" dialog.
For more information, see
●
chapter 4.4, "Overview of the Demodulation Process" , on page 88
Message: 'Sync Prefers Longer Pattern'
This message can only occur if the coarse synchronization is data-aided, i.e is based on a known pattern. In case the pattern is very short, pattern-based coarse synchronization might be unstable. If demodulation is stable, e.g. you get a reasonable EVM, there is no need to change anything. Otherwise, you have two options:
● Switch to the non-pattern-based mode by setting the parameter "Coarse Synchronization: Data "
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Frequently Asked Questions
(see
"Coarse Synchronization" on page 183
● If possible, use a longer pattern.
For more information, see
●
chapter 4.4, "Overview of the Demodulation Process" , on page 88
Message: 'Result Ranges Overlap'
This message does not indicate an error. It is merely displayed to inform you that the defined result ranges in the capture buffer overlap. Thus, some captured data is evaluated more than once. For example, the same peak value may be listed several times if it is included in several result ranges, and averaging is performed on (partially) duplicate values. However, a negative influence on the measurement results is not to be expected.
10.3 Frequently Asked Questions
Problem: The trace is not entirely visible within the measurement window ................ 255
Problem: The measurement window does not show average results .........................256
Problem: The spectrum is not displayed in the logarithmic domain ............................ 257
Problem: the MSK/FSK signal demodulates on the R&S FSQ-K70, but not on the
R&S FPS-K70 or: Why do I have to choose different transmit filters in the R&S FSQ-
.......................................................................................258
Question: Why isn't the FSK Deviation Error in R&S FPS-K70 identical to the FSK DEV
......................................................................................... 260
Problem: The PSK/QAM Signal shows spikes in the Frequency Error result display . 261
.........................................................................261
............................................................................................. 261
Question: Why do the EVM results for my FSK-modulated signal look wrong?
Problem: The trace is not entirely visible within the measurement window
Solution:
● 1. Select the measurement window.
● 2. Press the AUTO key.
● 3. Press the "Y-Axis Auto Scale" softkey.
Problem: The trace of the measurement signal is visible in the measurement window; the trace of the reference signal is not
Solution:
● 1.Select the measurement window.
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● 2. Press the TRACE key.
● 3. Press the "Trace Config" softkey.
● 4. Select a second trace, choose "Clear Write" as "Trace Mode" and toggle to "Ref" in the "Evaluation" column.
Problem: The measurement window does not show average results
Solution:
● 1. Select the measurement window.
● 2. Press the TRACE key.
● 3. Press the "Trace Config" softkey.
● 4. Select a second trace and choose the preferred "Trace Mode", e.g. "Max Hold" or "Average".
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Frequently Asked Questions
Problem: The spectrum is not displayed in the logarithmic domain
Solution:
● 1. Select the measurement window.
● 2. Press the AMPT key.
● 3. Press the "Unit" softkey.
● 4. Press the "Y-Axis Unit" softkey.
● 5. Select dB.
Problem: The Vector I/Q result display and the Constellation I/Q result display look different
Reason:
● The Vector I/Q diagram shows the measurement signal after the measurement filter and synchronization.
● The Constellation I/Q diagram shows the de-rotated constellation (i.e. for a π/4-
DQPSK, 4 instead of 8 points are displayed). The inter-symbol interference has been removed.
In case the measurement filter does not remove the inter-symbol interference, the windows show measurements that are significantly different.
Problem: The Constellation I/Q measurement result display has a different number of constellation points in the R&S FSQ-K70 and the R&S FPS-K70
Reason:
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Frequently Asked Questions
In the FSQ-K70, the Constellation I/Q measurement displays the symbol instants of the
Vector I/Q measurement. Hence, this is a rotated constellation, e.g. for a π/4-DQPSK,
8 points are displayed.
In the R&S FPS-K70, the Constellation I/Q diagram shows the de-rotated constellation
(i.e. for a π/4-DQPSK, 4 instead of 8 points are displayed). The inter-symbol interference has been removed.
Note: The result display "I/Q Constellation (Rotated)" displays the rotated constellation, as the FSQ-K70 does.
For details on the Constellation I/Q diagram in the R&S
"Constellation I/Q" , on page 24.
Table 10-1: Constellation I/Q and Vector I/Q for pi/4-DQPSK modulation
R&S FSQ-K70 R&S FPS-K70
Problem: the MSK/FSK signal demodulates on the R&S FSQ-K70, but not on the
R&S FPS-K70 or: Why do I have to choose different transmit filters in the R&S
FSQ-K70 and the R&S FPS-K70?
When generating an MSK/FSK reference signal, the R&S FSQ-K70 automatically replaces the Dirac pulses generated by the frequency mapper with square pulses with the length of one symbol. In the R&S FPS-K70, however, this "replacement" is part of the transmit filter routine. Thus, the R&S FSQ and the R&S FPS require different transmit filters for measuring the same FSK/MSK signal.
Example:
● If your transmit filter for the R&S FSQ-K70 was "NONE", you need to choose "Rectangular" as the transmit filter type in the R&S FPS.
● If your transmit filter for the R&S FSQ-K70 was "GAUSS", you need to choose
"GMSK" as the transmit filter type in the R&S FPS.
Problem: The EVM trace looks okay, but the EVM in the result summary is significantly different
Solution:
● Make sure that the position of the "Evaluation Lines" is reasonable. The Result
Summary only evaluates sample instants that are within the evaluation lines.
Hence, in the case the "Result Range" covers the burst ramps, it is important to adjust the "Evaluation Range" appropriately.
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Fig. 10-12: Problem: EVM in result summary does not correspond with trace display
Fig. 10-13: Solution: Result Summary with correct evaluation range setting
● Make sure that the same samples are evaluated. By default, the EVM trace displays all sample instants, e.g. if the sample rate is 4, the EVM trace shows 4 samples per symbol. The Result Summary does not automatically evaluate all sample
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Frequently Asked Questions instants. E.g. for a PSK modulation, by default only symbol instants contribute to the EVM result.
Question: Why isn't the FSK Deviation Error in R&S FPS-K70 identical to the FSK
DEV ERROR in R&S FSQ-K70?
Solution:
The FSK deviation error in the R&S FPS-K70 is calculated as the difference between the measured frequency deviation and the reference frequency deviation as entered by the user (see
"FSK Ref Deviation (FSK only)" on page 137). What is referred to as the
"FSK DEV ERROR" in the R&S FSQ-K70 is calculated differently (see the R&S FSQ-
K70 Software Manual) and is comparable to the "Freq Err RMS" in the R&S FPS-K70.
However, while the "FSK DEV ERROR" in the R&S FSQ-K70 is given in Hz, the "Freq
Err RMS" in the R&S FPS-K70 is given in percent, i.e. relative to the "FSK Meas Deviation".
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Frequently Asked Questions
Problem: The PSK/QAM Signal shows spikes in the Frequency Error result display
Solution:
These spikes are usually uncritical and are caused by zero-transitions in the I/Q Plane.
Question: The y-axis unit for the spectrum of the measurement signal can be chosen to be "dB". What level is this relative to?
Answer:
Spectrum (RealImag, Meas&Ref) calculates the FFT of the result RealImag(Meas&Ref). RealImag(Meas&Ref) has the unit "none". In this case, "none" means the measured signal has been scaled such that it matches the ideal corresponding reference signal as well as possible. The reference signal in turn is scaled such that max(abs(at symbol instants)) = 1.0.
Question: How can I get the demodulated symbols of all my GSM bursts in the capture buffer in remote control?
Answer:
Use the following remote commands:
:SENSe1:DDEMod:PRESet 'GSM_NB'
Load the GSM standard.
:SENSe1:DDEMod:RLENgth 10000 SYM
Enlarge the capture buffer length such that all the bursts you want to demodulate can be seen within the capture buffer.
:INITiate1:CONTinuous OFF
Go to single sweep mode.
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:SENSe1:SWEep:COUNt 0
Set the "Statistic Count" to "Auto" mode.
:INITiate1:IMMediate
Do single sweep.
:SENSe1:SWEep:COUNt:CURRent?
Query the number of demodulated bursts within the capture buffer.
For n = 1:NumberOfBursts
:SENSe1:DDEMod:SEARch:MBURst:CALC n
:TRACe4? TRACe1 'Query the result symbols in window D
End
Step through all bursts and query the demodulated symbols.
Question: Why do the EVM results for my FSK-modulated signal look wrong?
Answer:
For an FSK-modulated signal, the signal processing differs to an PSK/QAM/MSKmodulated signal. The estimation model does not minimize the EVM but the error of
the instantaneous frequency (see chapter 4.5.2.1, "Error Model" , on page 112). There-
fore, the measurement value that corresponds to the EVM value for FSK is the the Frequency Error (Absolute/Relative). (Source Type: Modulation Error; Result Type: Frequency Error (Absolute/Relative))
10.4 Obtaining Technical Support
If problems occur, the instrument generates error messages which in most cases will be sufficient for you to detect the cause of an error and find a remedy.
Error messages are described in chapter 10.2, "Explanation of Error Messages" , on page 246.
In addition, our customer support centers are there to assist you in solving any problems that you may encounter with your R&S FPS. We will find solutions more quickly and efficiently if you provide us with the information listed below.
● System Configuration: The "System Configuration" dialog box (in the "Setup" menu of the soft front panel) provides information on:
– Hardware Info: hardware assemblies
– Versions and Options: the status of all software and hardware options installed on your instrument
– System Messages: messages on any errors that may have occurred
An .xml file with information on the system configuration ("device footprint") can be created automatically (using the DIAGnostic:SERVice:SINFo command or as described in
"To collect the support information" on page 263).
● Error Log: The RSError.log file (in the log directory of the main installation directory) contains a chronological record of errors.
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Obtaining Technical Support
● Support file: a *.zip file with important support information can be created automatically. The *.zip file contains the system configuration information ("device footprint"), the current eeprom data and a screenshot of the screen display.
To collect the support information
1. Select the SETUP key in the soft front panel on the Remote Desktop.
2. Select "Service > R&S Support" and then "Create R&S Support Information".
The file is stored as C:\R_S\instr\user\service.zip.
Attach the support file to an e-mail in which you describe the problem and send it to the customer support address for your region as listed in the Internet ( http:// www.rohde-schwarz.com/en/service-support/customer_support_107711.html
).
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Introduction
11 Remote Commands for VSA
The following commands are required to perform measurements in VSA in a remote environment.
It is assumed that the R&S FPS has already been set up for remote control in a network as described in the R&S FPS User Manual.
Note that basic tasks that are also performed in the base unit in the same way are not described here. For a description of such tasks, see the R&S FPS User Manual.
In particular, this includes:
● Managing Settings and Results, i.e. storing and loading settings and result data
● Basic instrument configuration, e.g. checking the system configuration, customizing the screen layout, or configuring networks and remote operation
● Using the common status registers
The following tasks specific to VSA are described here:
11.1 Introduction
Commands are program messages that a controller (e.g. a PC) sends to the instrument or software. They operate its functions ('setting commands' or 'events') and request information ('query commands'). Some commands can only be used in one way, others work in two ways (setting and query). If not indicated otherwise, the commands can be used for settings and queries.
The syntax of a SCPI command consists of a header and, in most cases, one or more parameters. To use a command as a query, you have to append a question mark after the last header element, even if the command contains a parameter.
A header contains one or more keywords, separated by a colon. Header and parameters are separated by a "white space" (ASCII code 0 to 9, 11 to 32 decimal, e.g. blank).
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Introduction
If there is more than one parameter for a command, these are separated by a comma from one another.
Only the most important characteristics that you need to know when working with SCPI commands are described here. For a more complete description, refer to the User
Manual of the R&S FPS.
Remote command examples
Note that some remote command examples mentioned in this general introduction may not be supported by this particular application.
11.1.1 Conventions used in Descriptions
Note the following conventions used in the remote command descriptions:
● Command usage
If not specified otherwise, commands can be used both for setting and for querying parameters.
If a command can be used for setting or querying only, or if it initiates an event, the usage is stated explicitely.
● Parameter usage
If not specified otherwise, a parameter can be used to set a value and it is the result of a query.
Parameters required only for setting are indicated as Setting parameters.
Parameters required only to refine a query are indicated as Query parameters.
Parameters that are only returned as the result of a query are indicated as Return
values.
● Conformity
Commands that are taken from the SCPI standard are indicated as SCPI con-
firmed. All commands used by the R&S FPS follow the SCPI syntax rules.
● Asynchronous commands
A command which does not automatically finish executing before the next command starts executing (overlapping command) is indicated as an Asynchronous
command.
● Reset values (*RST)
Default parameter values that are used directly after resetting the instrument (*RST command) are indicated as *RST values, if available.
● Default unit
This is the unit used for numeric values if no other unit is provided with the parameter.
● Manual operation
If the result of a remote command can also be achieved in manual operation, a link to the description is inserted.
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Introduction
11.1.2 Long and Short Form
The keywords have a long and a short form. You can use either the long or the short form, but no other abbreviations of the keywords.
The short form is emphasized in upper case letters. Note however, that this emphasis only serves the purpose to distinguish the short from the long form in the manual. For the instrument, the case does not matter.
Example:
SENSe:FREQuency:CENTer is the same as SENS:FREQ:CENT.
11.1.3 Numeric Suffixes
Some keywords have a numeric suffix if the command can be applied to multiple instances of an object. In that case, the suffix selects a particular instance (e.g. a measurement window).
Numeric suffixes are indicated by angular brackets (<n>) next to the keyword.
If you don't quote a suffix for keywords that support one, a 1 is assumed.
Example:
DISPlay[:WINDow<1...4>]:ZOOM:STATe enables the zoom in a particular measurement window, selected by the suffix at WINDow.
DISPlay:WINDow4:ZOOM:STATe ON refers to window 4.
11.1.4 Optional Keywords
Some keywords are optional and are only part of the syntax because of SCPI compliance. You can include them in the header or not.
Note that if an optional keyword has a numeric suffix and you need to use the suffix, you have to include the optional keyword. Otherwise, the suffix of the missing keyword is assumed to be the value 1.
Optional keywords are emphasized with square brackets.
Example:
Without a numeric suffix in the optional keyword:
[SENSe:]FREQuency:CENTer is the same as FREQuency:CENTer
With a numeric suffix in the optional keyword:
DISPlay[:WINDow<1...4>]:ZOOM:STATe
DISPlay:ZOOM:STATe ON enables the zoom in window 1 (no suffix).
DISPlay:WINDow4:ZOOM:STATe ON enables the zoom in window 4.
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Introduction
11.1.5 Alternative Keywords
A vertical stroke indicates alternatives for a specific keyword. You can use both keywords to the same effect.
Example:
[SENSe:]BANDwidth|BWIDth[:RESolution]
In the short form without optional keywords, BAND 1MHZ would have the same effect as BWID 1MHZ.
11.1.6 SCPI Parameters
Many commands feature one or more parameters.
If a command supports more than one parameter, these are separated by a comma.
Example:
LAYout:ADD:WINDow Spectrum,LEFT,MTABle
Parameters may have different forms of values.
11.1.6.1
Numeric Values
Numeric values can be entered in any form, i.e. with sign, decimal point or exponent. In case of physical quantities, you can also add the unit. If the unit is missing, the command uses the basic unit.
Example: with unit: SENSe:FREQuency:CENTer 1GHZ without unit: SENSe:FREQuency:CENTer 1E9 would also set a frequency of 1 GHz.
Values exceeding the resolution of the instrument are rounded up or down.
If the number you have entered is not supported (e.g. in case of discrete steps), the command returns an error.
Instead of a number, you can also set numeric values with a text parameter in special cases.
● MIN/MAX
Defines the minimum or maximum numeric value that is supported.
● DEF
Defines the default value.
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● UP/DOWN
Increases or decreases the numeric value by one step. The step size depends on the setting. In some cases you can customize the step size with a corresponding command.
Querying numeric values
When you query numeric values, the system returns a number. In case of physical quantities, it applies the basic unit (e.g. Hz in case of frequencies). The number of digits after the decimal point depends on the type of numeric value.
Example:
Setting: SENSe:FREQuency:CENTer 1GHZ
Query: SENSe:FREQuency:CENTer? would return 1E9
In some cases, numeric values may be returned as text.
● INF/NINF
Infinity or negative infinity. Represents the numeric values 9.9E37 or -9.9E37.
● NAN
Not a number. Represents the numeric value 9.91E37. NAN is returned in case of errors.
11.1.6.2
Boolean
Boolean parameters represent two states. The "ON" state (logically true) is represented by "ON" or a numeric value 1. The "OFF" state (logically untrue) is represented by
"OFF" or the numeric value 0.
Querying boolean parameters
When you query boolean parameters, the system returns either the value 1 ("ON") or the value 0 ("OFF").
Example:
Setting: DISPlay:WINDow:ZOOM:STATe ON
Query: DISPlay:WINDow:ZOOM:STATe? would return 1
11.1.6.3
Character Data
Character data follows the syntactic rules of keywords. You can enter text using a short or a long form. For more information see
chapter 11.1.2, "Long and Short Form" , on page 266.
Querying text parameters
When you query text parameters, the system returns its short form.
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Common Suffixes
Example:
Setting: SENSe:BANDwidth:RESolution:TYPE NORMal
Query: SENSe:BANDwidth:RESolution:TYPE? would return NORM
11.1.6.4
Character Strings
Strings are alphanumeric characters. They have to be in straight quotation marks. You can use a single quotation mark ( ' ) or a double quotation mark ( " ).
Example:
INSTRument:DELete 'Spectrum'
11.1.6.5
Block Data
Block data is a format which is suitable for the transmission of large amounts of data.
The ASCII character # introduces the data block. The next number indicates how many of the following digits describe the length of the data block. In the example the 4 following digits indicate the length to be 5168 bytes. The data bytes follow. During the transmission of these data bytes all end or other control signs are ignored until all bytes are transmitted. #0 specifies a data block of indefinite length. The use of the indefinite format requires a NL^END message to terminate the data block. This format is useful when the length of the transmission is not known or if speed or other considerations prevent segmentation of the data into blocks of definite length.
11.2 Common Suffixes
In VSA, the following common suffixes are used in remote commands:
Suffix
<m>
<n>
<t>
Value range
1..4
1..16
1..6
Description
Marker
Window
Trace
11.3 Activating Vector Signal Analysis
Vector signal analysis requires a special application on the R&S FPS. A measurement is started immediately with the default settings.
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INSTrument:CREate:DUPLicate
This command duplicates the currently selected measurement channel, i.e creates a new measurement channel of the same type and with the identical measurement settings. The name of the new channel is the same as the copied channel, extended by a consecutive number (e.g. "Spectrum" -> "Spectrum 2").
The channel to be duplicated must be selected first using the INST:SEL command.
Example: INST:SEL 'Spectrum'
INST:CRE:DUPL
Duplicates the channel named 'Spectrum' and creates a new measurement channel named 'Spectrum 2'.
Usage: Event
INSTrument:CREate[:NEW] <ChannelType>, <ChannelName>
This command adds an additional measurement channel.
The number of measurement channels you can configure at the same time depends on available memory.
Parameters:
<ChannelType>
<ChannelName>
Channel type of the new channel.
For a list of available channel types see
String containing the name of the channel. The channel name is displayed as the tab label for the measurement channel.
Note: If the specified name for a new channel already exists, the default name, extended by a sequential number, is used for the new channel (see
Example: INST:CRE SAN, 'Spectrum 2'
Adds an additional spectrum display named "Spectrum 2".
INSTrument:CREate:REPLace <ChannelName1>,<ChannelType>,<ChannelName2>
This command replaces a measurement channel with another one.
Setting parameters:
<ChannelName1> String containing the name of the measurement channel you want to replace.
<ChannelType> Channel type of the new channel.
For a list of available channel types see
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<ChannelName2> String containing the name of the new channel.
Note: If the specified name for a new channel already exists, the default name, extended by a sequential number, is used for the new channel (see
Example:
Usage:
INST:CRE:REPL 'Spectrum2',IQ,'IQAnalyzer'
Replaces the channel named 'Spectrum2' by a new measurement channel of type 'IQ Analyzer' named 'IQAnalyzer'.
Setting only
INSTrument:DELete <ChannelName>
This command deletes a measurement channel.
If you delete the last measurement channel, the default "Spectrum" channel is activated.
Parameters:
<ChannelName> String containing the name of the channel you want to delete.
A measurement channel must exist in order to be able delete it.
Example:
Usage:
INST:DEL 'Spectrum4'
Deletes the channel with the name 'Spectrum4'.
Event
INSTrument:LIST?
This command queries all active measurement channels. This is useful in order to obtain the names of the existing measurement channels, which are required in order to replace or delete the channels.
Return values:
<ChannelType>,
<ChannelName>
For each channel, the command returns the channel type and channel name (see tables below).
Tip: to change the channel name, use the INSTrument:
Example:
Usage:
INST:LIST?
Result for 3 measurement channels:
'ADEM','Analog Demod','IQ','IQ
Analyzer','IQ','IQ Analyzer2'
Query only
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Activating Vector Signal Analysis
Table 11-1: Available measurement channel types and default channel names in Signal and Spectrum
Analyzer mode
Application <ChannelType>
Parameter
Default Channel Name*)
Spectrum
I/Q Analyzer
Analog Demodulation (R&S FPS-K7)
GSM (R&S FPS-K10)
Noise (R&S FPS-K30)
Phase Noise (R&S FPS-K40)
VSA (R&S FPS-K70)
3GPP FDD BTS (R&S FPS-K72)
3GPP FDD UE (R&S FPS-K73)
TD-SCDMA BTS (R&S FPS-K76)
TD-SCDMA UE (R&S FPS-K77) cdma2000 BTS (R&S FPS-K82) cdma2000 MS (R&S FPS-K83)
1xEV-DO BTS (R&S FPS-K84)
1xEV-DO MS (R&S FPS-K85)
WLAN (R&S FPS-K91)
LTE (R&S FPS-K10x)
SANALYZER
IQ
ADEM
GSM
NOISE
PNOISE
DDEM
BWCD
MWCD
BTDS
MTDS
BC2K
MC2K
BDO
MDO
WLAN
LTE
Spectrum
IQ Analyzer
Analog Demod
GSM
Noise
Phase Noise
VSA
3G FDD BTS
3G FDD UE
TD-SCDMA BTS
TD-SCDMA UE
CDMA2000 BTS
CDMA2000 MS
1xEV-DO BTS
1xEV-DO MS
WLAN
LTE
Note: the default channel name is also listed in the table. If the specified name for a new channel already exists, the default name, extended by a sequential number, is used for the new channel.
INSTrument:REName <ChannelName1>, <ChannelName2>
This command renames a measurement channel.
Parameters:
<ChannelName1> String containing the name of the channel you want to rename.
<ChannelName2> String containing the new channel name.
Note that you can not assign an existing channel name to a new channel; this will cause an error.
Example:
Usage:
INST:REN 'Spectrum2','Spectrum3'
Renames the channel with the name 'Spectrum2' to 'Spectrum3'.
Setting only
INSTrument[:SELect] <ChannelType>
Selects the application (channel type) for the current channel.
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Digital Standards
See also
INSTrument:CREate[:NEW] on page 270.
For a list of available channel types see
Parameters:
<ChannelType> VSA
VSA, R&S FPS-K70
SYSTem:PRESet:CHANnel[:EXECute]
This command restores the default instrument settings in the current channel.
Use INST:SEL to select the channel.
Example: INST 'Spectrum2'
Selects the channel for "Spectrum2".
SYST:PRES:CHAN:EXEC
Restores the factory default settings to the "Spectrum2" channel.
Usage: Event
Manual operation: See
11.4 Digital Standards
Various predefined settings files for common digital standards are provided for use with the VSA application. In addition, you can create your own settings files for user-specific measurements.
Manual configuration of digital standards is described in
According to Digital Standards" , on page 129.
[SENSe:]DDEMod:FACTory[:VALue] <Factory>
This command restores the factory settings of standards or patterns for the VSA application.
Setting parameters:
<Factory> ALL | STANdard | PATTern
ALL
Restores both standards and patterns.
*RST: ALL
Usage: Setting only
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Digital Standards
Manual operation: See
"Restore Standard Files" on page 129
See
"Restore Pattern Files" on page 129
[SENSe:]DDEMod:PRESet[:STANdard] <Standard>
This command selects an automatic setting of all modulation parameters according to a standardized transmission method or a user-defined transmission method. The standardized transmission methods are available in the instrument as predefined standards.
Setting parameters:
<Standard> string
Specifies the file name that contains the transmission method without the extension. For user-defined standards, the file path must be included. Default standards predefined by
Rohde&Schwarz do not require a path definition. A list of predefined standards (including short forms) is provided in the annex
(see chapter A.2, "Predefined Standards and Settings" , on page 412).
Example: DDEM:PRES 'TETRA_NDDOWN'
Switches the predefined digital standard "TETRA_DiscontinuousDownlink" on.
DDEM:PRES 'C:\R_S\Instr\usr\standards\USER_GSM'
Switches the user-defined digital standard "USER_GSM" on.
Example: See
chapter 11.13.2, "Measurement Example 2: GSM EDGE
Burst Measurement Based on a Digital Standard" , on page 405.
Manual operation: See
[SENSe:]DDEMod:STANdard:COMMent <Comment>
This command enters the comment for a new standard. The comment is stored with the standard and is only displayed in the selection menu (manual operation). When remote control is used, the string is deleted after the standard has been stored, allowing a new comment to be entered for the next standard. In this case a blank string is returned when a query is made.
Setting parameters:
<Comment> string
Manual operation: See
[SENSe:]DDEMod:STANdard:DELete <FileName>
This command deletes a specified digital standard file in the vector signal analysis. The file name includes the path. If the file does not exist, an error message is displayed
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Configuring VSA
Setting parameters:
<FileName> string
File name including the path for the digital standard file
Usage: Setting only
Manual operation: See
[SENSe:]DDEMod:STANdard:PREset[:VALue]
This command restores the default settings of the currently selected standard.
Usage: Event
[SENSe:]DDEMod:STANdard:SAVE <FileName>
This command stores the current settings of the vector signal analysis as a new userdefined digital standard. If the name of the digital standard is already in use, an error message is output and a new name has to be selected. It is recommended that you define a comment before storing the standard.
Setting parameters:
<FileName> string
The path and file name to which the settings are stored.
Example:
Example:
DDEM:STAN:COMM 'GSM_AccessBurst with Pattern'
Defines a comment for the settings.
DDEM:STAN:SAVE 'C:
\R_S\Instr\usr\standards\USER_GSM'
Stores the settings in the user-defined digital standard
"USER_GSM".
See
chapter 11.13.3, "Measurement Example 3: User-Defined
Pattern Search and Limit Check" , on page 409.
Usage: Setting only
Manual operation: See
11.5 Configuring VSA
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Configuring VSA
11.5.1 Signal Description
The signal description provides information on the expected input signal, which optimizes pattern and burst detection and the calculation of the ideal reference signal.
Manual configuration of the signal description is described in chapter 5.4, "Signal
11.5.1.1
Modulation
The modulation settings vary depending on the selected modulation type; in particular,
FSK modulation provides some additional settings.
[SENSe:]DDEMod:MAPPing:CATalog?
............................................................................ 279
CALCulate<n>:FSK:DEViation:REFerence:RELative <FSKRefDev>
This command defines the deviation to the reference frequency for FSK modulation as a multiple of the symbol rate.
For details see
"FSK Ref Deviation (FSK only)" on page 137.
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Configuring VSA
Setting parameters:
<FSKRefDev> numeric value
Range:
*RST:
0.1 to 15
1
Default unit: NONE
Manual operation: See
"FSK Ref Deviation (FSK only)" on page 137
CALCulate<n>:FSK:DEViation:REFerence[:VALue] <FSKRefDevAbsRes>
This command defines the deviation to the reference frequency for FSK modulation as an absolute value in Hz.
Setting parameters:
<FSKRefDevAbsRes>numeric value
Range:
*RST:
10.0 to 64e9
100e3
Default unit: Hz
Manual operation: See
"FSK Ref Deviation (FSK only)" on page 137
[SENSe:]DDEMod:APSK:NSTate <APSKNstate>
This command defines the specific demodulation mode for APSK. The following APSK demodulation modes are possible: DDEMod:APSK:NSTate 16 16APSK 32 32APSK
Setting parameters:
<APSKNstate> numeric value
*RST: 16
Manual operation: See
"Modulation Order" on page 136
[SENSe:]DDEMod:ASK:NSTate <ASKNstate>
This command defines the specific demodulation mode for ASK. The following ASK demodulation modes are possible: DDEMod:ASK:NSTate 2 OOK 4 4ASK
Setting parameters:
<ASKNstate> numeric value
*RST: 2
Manual operation: See
"Modulation Order" on page 136
[SENSe:]DDEMod:FILTer:ALPHa <MeasFiltAlphaBT>
This command determines the filter characteristic (ALPHA/BT). The resolution is 0.01.
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Configuring VSA
Setting parameters:
<MeasFiltAlphaBT> numeric value
Range:
*RST:
0.1 to 1.0
0.22
Default unit: NONE
[SENSe:]DDEMod:FILTer[:STATe] <MeasFilterState>
This command defines whether the input signal that is evaluated is filtered by the measurement filter. This command has no effect on the transmit filter.
Setting parameters:
<MeasFilterState> ON | OFF | 1 | 0
ON
[SENSe:]DDEMod:MFILter:AUTO is activated.
OFF
The input signal is not filtered. [SENSe:]DDEMod:MFILter:
*RST: 1
[SENSe:]DDEMod:FORMat <Group>
This command selects the digital demodulation mode.
Setting parameters:
<Group> MSK | PSK | QAM | QPSK | FSK | ASK | APSK | UQAM
QPSK
Quad Phase Shift Key
PSK
Phase Shift Key
MSK
Minimum Shift Key
QAM
Quadrature Amplitude Modulation
FSK
Frequency Shift Key
ASK
Amplitude Shift Keying
APSK
Amplitude Phase Shift Keying
UQAM
User-defined modulation (loaded from file, see
]DDEMod:USER:NAME on page 284)
*RST: PSK
Example: SENS:DDEM:FORM QAM
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Configuring VSA
Example:
Example:
See
chapter 11.13.1, "Measurement Example 1: User-defined
Measurement of Continuous QPSK Signal" , on page 404.
See
chapter 11.13.3, "Measurement Example 3: User-Defined
Pattern Search and Limit Check" , on page 409.
Manual operation: See
See
"Load User Modulation" on page 136
[SENSe:]DDEMod:FSK:NSTate <FSKNstate>
This command defines the demodulation of the FSK modulation scheme.
Setting parameters:
<FSKNstate> 2 | 4 | 8
2
2FSK
4
4FSK
8
8FSK
*RST: 2
Manual operation: See
"Modulation Order" on page 136
[SENSe:]DDEMod:MAPPing:CATalog?
This command queries the names of all mappings that are available for the current modulation type and order. A mapping describes the assignment of constellation points to symbols.
Return values:
<Mappings> A comma-separated list of strings, with one string for each mapping name.
Example:
Example:
:SENSe:DDEMod:MAPPing:CATalog?
Result:
'CDMA2K_FWD','DVB_S2','GRAY','NATURAL','WCDMA'
See
chapter 11.13.1, "Measurement Example 1: User-defined
Measurement of Continuous QPSK Signal" , on page 404.
Usage: Query only
Manual operation: See
"Modulation Mapping" on page 137
[SENSe:]DDEMod:MAPPing[:VALue] <Mapping>
To obtain a list of available symbol mappings for the current modulation type use the
[SENSe:]DDEMod:MAPPing:CATalog?
? query.
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Configuring VSA
Setting parameters:
<Mapping> string
Example:
Example:
SENS:DDEM:MAPP 'GSM'
Sets mapping to GSM.
See
chapter 11.13.1, "Measurement Example 1: User-defined
Measurement of Continuous QPSK Signal" , on page 404.
Example: See
chapter 11.13.3, "Measurement Example 3: User-Defined
Pattern Search and Limit Check" , on page 409.
Manual operation: See
"Modulation Mapping" on page 137
[SENSe:]DDEMod:MSK:FORMat <MSKformat>
This command defines the specific demodulation order for MSK.
Setting parameters:
<MSKformat> TYPE1 | TYPE2 | NORMal | DIFFerential
TYPE1 | NORMal
Demodulation order MSK is used.
TYPE2 | DIFFerential
Demodulation order DMSK is used.
*RST: TYPE1
Manual operation: See
"Modulation Order" on page 136
[SENSe:]DDEMod:PSK:FORMat <PSKformat>
Together with DDEMod:PSK:NST, this command defines the demodulation order for
PSK (see also [SENSe:]DDEMod:PSK:NSTate on page 281). Depending on the
demodulation format and state, the following orders are available:
8
8
8
NSTATe
2
8
<Name> any
NORMal
DIFFerential
N3Pi8
PI8D8PSK
Order
BPSK
8PSK
D8PSK
3pi/8-8PSK (EDGE)
Pi/8-D8PSK
Setting parameters:
<PSKformat> NORMal | DIFFerential | N3Pi8 | PI8D8PSK
*RST: NORMal
Manual operation: See
"Modulation Order" on page 136
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Configuring VSA
[SENSe:]DDEMod:PSK:NSTate <PSKNstate>
Together with DDEMod:PSK:FORMat, this command defines the demodulation order for PSK (see also
[SENSe:]DDEMod:PSK:FORMat on page 280).
Setting parameters:
<PSKNstate> 2 | 8
*RST: 2
Manual operation: See
"Modulation Order" on page 136
[SENSe:]DDEMod:QAM:FORMat <QAMformat>
This command defines the specific demodulation order for QAM.
Setting parameters:
<QAMformat> NORMal | DIFFerential | NPI4 | MNPI4
NORMal
Demodulation order QAM is used.
DIFFerential
Demodulation order DQAM is used.
NPI4
Demodulation order π/4-16QAM is used.
MNPI4
Demodulation order π/4-32QAM is used.
*RST: NORMal
Manual operation: See
"Modulation Order" on page 136
[SENSe:]DDEMod:QAM:NSTate <QAMNState>
This command defines the demodulation order for QAM.
128
256
512
1024
<QAMNSTate>
16
16
32
32
64
Order
16QAM
Pi/4-16QAM
32QAM
Pi/4-32QAM
64QAM
128QAM
256QAM
512QAM
1024QAM
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Configuring VSA
Setting parameters:
<QAMNState> numeric value
*RST: 16
Manual operation: See
"Modulation Order" on page 136
[SENSe:]DDEMod:QPSK:FORMat <QPSKformat>
This command defines the demodulation order for QPSK.
Setting parameters:
<QPSKformat> NORMal | DIFFerential | NPI4 | DPI4 | OFFSet | N3PI4
NORMal
Demodulation order QPSK is used.
DIFFerential
Demodulation order DQPSK is used.
NPI4
Demodulation order π/4 QPSK is used.
DPI4
Demodulation order π/4 DQPSK is used.
OFFSet
Demodulation order OQPSK is used.
N3PI4
Demodulation order 3 π/4 QPSK is used.
*RST: NORMal
Example:
Example:
Example:
DDEM:FORM QPSK
Switches QPSK demodulation on.
DDEM:QPSK:FORM DPI4
Switches π/4 DQPSK demodulation order on.
See
chapter 11.13.1, "Measurement Example 1: User-defined
Measurement of Continuous QPSK Signal" , on page 404.
See
chapter 11.13.3, "Measurement Example 3: User-Defined
Pattern Search and Limit Check" , on page 409.
Manual operation: See
"Modulation Order" on page 136
[SENSe:]DDEMod:SRATe <SymbolRate>
This command defines the symbol rate.
The minimum symbol rate is 25 Hz. The maximum symbol rate depends on the defined
chapter 4.2, "Sample Rate, Symbol Rate and I/Q Bandwidth" , on page 63).
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Configuring VSA
Setting parameters:
<SymbolRate> numeric value
Range:
*RST:
25 to 250e6
3.84e6
Default unit: Hz
Example:
Example:
See
chapter 11.13.1, "Measurement Example 1: User-defined
Measurement of Continuous QPSK Signal" , on page 404.
See
chapter 11.13.3, "Measurement Example 3: User-Defined
Pattern Search and Limit Check" , on page 409.
Manual operation: See
[SENSe:]DDEMod:TFILter:ALPHa <Alpha>
This command determines the filter characteristic (ALPHA/BT). The resolution is 0.01.
Setting parameters:
<Alpha> numeric value
Range: 0.1 to 1.0
*RST: 0.22
Default unit: NONE
Example: See
chapter 11.13.1, "Measurement Example 1: User-defined
Measurement of Continuous QPSK Signal" , on page 404.
Manual operation: See
See
[SENSe:]DDEMod:TFILter:NAME <Name>
This command selects a transmit filter and automatically switches it on.
For more information on transmit filters, refer to
chapter A.3.1, "Transmit Filters" , on page 419.
Setting parameters:
<Name> string
Name of the Transmit filter; an overview of available transmit filters is provided in
chapter A.3.1, "Transmit Filters" , on page 419.
Example: See
chapter 11.13.1, "Measurement Example 1: User-defined
Measurement of Continuous QPSK Signal" , on page 404.
Manual operation: See
"Transmit Filter Type" on page 138
See
"Load User Filter" on page 138
[SENSe:]DDEMod:TFILter[:STATe] <TXFilterState>
Use this command to switch the transmit filter off. To switch a transmit filter on, use the
command.
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Configuring VSA
Setting parameters:
<TXFilterState> ON | OFF | 1 | 0
OFF
Switches the transmit filter off.
ON
Switches the transmit filter specified by
TFILter:NAME on. However, this command is not necessary,
as the
[SENSe:]DDEMod:TFILter:NAME command automati-
cally switches the filter on.
*RST: 1
Manual operation: See
"Transmit Filter Type" on page 138
[SENSe:]DDEMod:TFILter:USER <FilterName>
This command selects a user-defined transmit filter file.
Setting parameters:
<FilterName> The name of the transmit filter file.
Manual operation: See
"Transmit Filter Type" on page 138
See
"Load User Filter" on page 138
[SENSe:]DDEMod:USER:NAME <Name>
Selects the file that contains the user-defined modulation to be loaded.
Setting parameters:
<Name> string
Path and file name of the *.vam file
Example: SENS:DDEM:FORM UQAM
Define the use of a user-defined modulation
SENS:DDEM:USER:NAME 'D:\MyModulation.vam'
Select the file name to be loaded
Manual operation: See
"Load User Modulation" on page 136
11.5.1.2
Signal Structure
The signal structure commands describe the expected input signal and determine which settings are available for configuration. You can define a pattern to which the instrument can be synchronized, thus adapting the result range.
[SENSe:]DDEMod:SEARch:BURSt:LENGth:MAXimum ......................................................285
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Configuring VSA
[SENSe:]DDEMod:SEARch:BURSt:LENGth:MAXimum <MaxLength>
This command defines the maximum useful length of a burst. Only those bursts will be recognized that fall below this length. The default unit is symbols. The value can also be given in seconds.
Setting parameters:
<MaxLength> numeric value
Range:
*RST:
0 to 32000
1600
Default unit: SYM
Manual operation: See
"Min Length / Max Length" on page 140
[SENSe:]DDEMod:SEARch:BURSt:LENGth[:MINimum] <UsefulLength>
This command defines the minimum useful length of a burst. Only those bursts will be recognized that exceed this length. The default unit is symbols. The value can also be given in seconds.
Note the difference to manual operation:
<Min_length>
Manual
= <Min_Useful_Length> + <Run-In> + <Run-Out>
Setting parameters:
<UsefulLength> numeric value
Range:
*RST:
10 to 32000
100
Default unit: SYM
Manual operation: See
"Min Length / Max Length" on page 140
[SENSe:]DDEMod:SEARch:BURSt:SKIP:FALLing <RunOut>
This command defines the length of the falling burst edge which is not considered when evaluating the result. The default unit is symbols. The value can also be given in seconds.
Setting parameters:
<RunOut> numeric value
Range:
*RST:
0 to 31990
1
Default unit: SYM
Manual operation: See
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[SENSe:]DDEMod:SEARch:BURSt:SKIP:RISing <RunIn>
This command defines the length of the rising burst edge which is not considered when evaluating the result. The default unit is symbols. The value can also be given in seconds
Setting parameters:
<RunIn> numeric value
Range:
*RST:
0 to 31990
1
Default unit: SYM
Manual operation: See
[SENSe:]DDEMod:SEARch:SYNC:CATalog <Patterns>
This command reads the names of all patterns stored on the hard disk. The file names are returned as a comma-separated list of strings, one for each file name (without the file extension).
Setting parameters:
<Patterns> CURRent | ALL
CURRent
Only patterns that belong to the current standard
ALL
All patterns
*RST: ALL
Example:
Example:
:DDEM:SEAR:SYNC:CAT? CURR
Result:
'GSM_AB0','GSM_AB1','GSM_AB2','GSM_TSC1'
See
chapter 11.13.3, "Measurement Example 3: User-Defined
Pattern Search and Limit Check" , on page 409.
[SENSe:]DDEMod:SIGNal:PATTern <PatternedSignal>
This command specifies whether the signal contains a pattern or not.
Setting parameters:
<PatternedSignal> ON | OFF | 1 | 0
*RST: 0
Example: See
chapter 11.13.3, "Measurement Example 3: User-Defined
Pattern Search and Limit Check" , on page 409.
Manual operation: See
[SENSe:]DDEMod:SIGNal[:VALue] <SignalType>
This command specifies whether the signal is bursted or continuous.
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Setting parameters:
<SignalType> CONTinuous | BURSted
*RST: CONTinuous
Example: See
chapter 11.13.3, "Measurement Example 3: User-Defined
Pattern Search and Limit Check" , on page 409.
Manual operation: See
[SENSe:]DDEMod:STANdard:SYNC:OFFSet:STATe <PattOffsState>
This command (de)activates the pattern offset.
Setting parameters:
<PattOffsState> ON | OFF | 1 | 0
*RST: 0
Example: See
chapter 11.13.3, "Measurement Example 3: User-Defined
Pattern Search and Limit Check" , on page 409.
Manual operation: See
[SENSe:]DDEMod:STANdard:SYNC:OFFSet[:VALue] <PatternOffset>
This command defines a number of symbols which are ignored before the comparison with the pattern starts.
Setting parameters:
<PatternOffset> numeric value
Range:
*RST:
0 to 15000
0
Default unit: SYM
Example: See
chapter 11.13.3, "Measurement Example 3: User-Defined
Pattern Search and Limit Check" , on page 409.
Manual operation: See
11.5.2 Input, Output and Frontend Settings
The R&S FPS can analyze signals from different input sources. The frequency and amplitude settings represent the "frontend" of the measurement setup.
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11.5.2.1
RF Input
INPut:ATTenuation:PROTection:RESet
This command resets the attenuator and reconnects the RF input with the input mixer after an overload condition occured and the protection mechanism intervened.The
error status bit (bit 3 in the STAT:QUES:POW status register) and the INPUT OVLD message in the status bar are cleared.
(For details on the status register see the R&S FPS User Manual).
The command works only if the overload condition has been eliminated first.
Usage: Event
INPut:COUPling <CouplingType>
This command selects the coupling type of the RF input.
Parameters:
<CouplingType> AC
AC coupling
DC
DC coupling
*RST: AC
Example:
Usage:
INP:COUP DC
SCPI confirmed
Manual operation: See
INPut:SELect <Source>
This command selects the signal source for measurements, i.e. it defines which connector is used to input data to the R&S FPS. If no additional input options are installed, only RF input is supported.
Parameters:
<Source> RF
Radio Frequency ("RF INPUT" connector)
*RST: RF
Manual operation: See
"Radio Frequency State" on page 143
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11.5.2.2
Output Settings
The following commands are required to query or provide output at the R&S FPS connectors.
OUTPut:IF[:SOURce] <Source>
Defines the type of signal available at the IF/VIDEO or IF OUT 2 GHZ connector of the
R&S FPS.
Parameters:
<Source> IF
The measured IF value is available at the IF/VIDEO output connector.
VIDeo
The displayed video signal (i.e. the filtered and detected IF signal, 200mV) is available at the IF/VIDEO output connector.
This setting is required to provide demodulated audio frequencies at the output.
*RST: IF
Example: OUTP:IF VID
Selects the video signal for the IF/VIDEO output connector.
Manual operation: See
OUTPut:TRIGger<port>:DIRection <Direction>
This command selects the trigger direction for trigger ports that serve as an input as well as an output.
Suffix:
<port>
.
Selects the used trigger port.
2 = TRG AUX
Parameters:
<Direction> INPut
Port works as an input.
OUTPut
Port works as an output.
*RST: INPut
Manual operation: See
OUTPut:TRIGger<port>:LEVel <Level>
This command defines the level of the signal generated at the trigger output.
This command works only if you have selected a user defined output with OUTPut:
.
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Suffix:
<port>
.
Selects the trigger port to which the output is sent.
2 = TRG AUX
Parameters:
<Level> HIGH
TTL signal.
LOW
0 V
*RST: LOW
Manual operation: See
See
OUTPut:TRIGger<port>:OTYPe <OutputType>
This command selects the type of signal generated at the trigger output.
Suffix:
<port>
.
Selects the trigger port to which the output is sent.
2 = TRG AUX
Parameters:
<OutputType> DEVice
Sends a trigger signal when the R&S FPS has triggered internally.
TARMed
Sends a trigger signal when the trigger is armed and ready for an external trigger event.
UDEFined
Sends a user defined trigger signal. For more information see
*RST: DEVice
Manual operation: See
OUTPut:TRIGger<port>:PULSe:IMMediate
This command generates a pulse at the trigger output.
Suffix:
<port>
.
Selects the trigger port to which the output is sent.
2 = TRG AUX
Usage: Event
Manual operation: See
OUTPut:TRIGger<port>:PULSe:LENGth <Length>
This command defines the length of the pulse generated at the trigger output.
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Suffix:
<port>
.
Selects the trigger port to which the output is sent.
2 = TRG AUX
Parameters:
<Length> Pulse length in seconds.
Manual operation: See
11.5.2.3
Frequency
[SENSe:]FREQuency:CENTer <Frequency>
This command defines the center frequency.
Parameters:
<Frequency> The allowed range and f max
is specified in the data sheet.
UP
Increases the center frequency by the step defined using the
[SENSe:]FREQuency:CENTer:STEP command.
DOWN
Decreases the center frequency by the step defined using the
[SENSe:]FREQuency:CENTer:STEP command.
*RST: fmax/2
Default unit: Hz
Example:
Usage:
FREQ:CENT 100 MHz
FREQ:CENT:STEP 10 MHz
FREQ:CENT UP
Sets the center frequency to 110 MHz.
SCPI confirmed
Manual operation: See
"Center frequency" on page 146
[SENSe:]FREQuency:CENTer:STEP <StepSize>
This command defines the center frequency step size.
You can increase or decrease the center frequency quickly in fixed steps using the
SENS:FREQ UP AND SENS:FREQ DOWN commands, see [SENSe:]FREQuency:
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Parameters:
<StepSize> f max
is specified in the data sheet.
Range:
*RST:
1 to fMAX
0.1 x span
Default unit: Hz
Example: FREQ:CENT 100 MHz
FREQ:CENT:STEP 10 MHz
FREQ:CENT UP
Sets the center frequency to 110 MHz.
Manual operation: See
"Center Frequency Stepsize" on page 146
[SENSe:]FREQuency:CENTer:STEP:AUTO <LinkMode>
Defines the step width of the center frequency.
Setting parameters:
<LinkMode> ON | OFF | 1 | 0
ON
Links the step width to the current standard (currently 1 MHz for all standards)
OFF
Sets the step width as defined using the FREQ:CENT:STEP
command (see [SENSe:]FREQuency:CENTer:STEP on page 291).
*RST: 1
Manual operation: See
"Center Frequency Stepsize" on page 146
[SENSe:]FREQuency:OFFSet <Offset>
This command defines a frequency offset.
If this value is not 0 Hz, the application assumes that the input signal was frequency shifted outside the application. All results of type "frequency" will be corrected for this shift numerically by the application.
See also
"Frequency Offset" on page 147.
Note: In MSRA mode, the setting command is only available for the MSRA Master. For
MSRA applications, only the query command is available.
Parameters:
<Offset> Range:
*RST:
-100 GHz to 100 GHz
0 Hz
Example: FREQ:OFFS 1GHZ
Usage: SCPI confirmed
Manual operation: See
"Frequency Offset" on page 147
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11.5.2.4
Amplitude Settings
Amplitude and scaling settings allow you to configure the vertical (y-)axis display and for some result displays also the horizontal (x-)axis.
Useful commands for amplitude settings described elsewhere:
●
●
[SENSe:]ADJust:LEVel on page 332
Remote commands exclusive to amplitude settings:
DISPlay[:WINDow<n>]:TRACe<t>:Y[:SCALe]:RLEVel:OFFSet ........................................... 293
DISPlay[:WINDow<n>]:TRACe<t>:Y[:SCALe]:RLEVel <ReferenceLevel>
This command defines the reference level (for all traces, <t> is irrelevant).
With a reference level offset ≠ 0, the value range of the reference level is modified by the offset.
Parameters:
<ReferenceLevel> The unit is variable.
Range:
*RST: see datasheet
0 dBm
Example:
Usage:
DISP:TRAC:Y:RLEV -60dBm
SCPI confirmed
Manual operation: See
DISPlay[:WINDow<n>]:TRACe<t>:Y[:SCALe]:RLEVel:OFFSet <Offset>
This command defines a reference level offset (for all traces, <t> is irrelevant).
Parameters:
<Offset> Range:
*RST:
-200 dB to 200 dB
0dB
Example: DISP:TRAC:Y:RLEV:OFFS -10dB
Manual operation: See
"Shifting the Display (Offset)" on page 148
[SENSe:]DDEMod:PRESet:RLEVel
This command initiates a measurement that evaluates and sets the ideal reference level for the current measurement. This ensures that the settings of the RF attenuation and the reference level are optimally adjusted to the signal level without overloading the R&S FPS or limiting the dynamic range by an S/N ratio that is too small.
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Usage: Event
INPut:GAIN:STATe <State>
This command turns 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.
Parameters:
<State>
Example:
Usage:
ON | OFF
*RST: OFF
INP:GAIN:STAT ON
Switches on 20 dB preamplification.
SCPI confirmed
Manual operation: See
"Preamplifier (option B22/B24)" on page 143
11.5.2.5
Attenuation
INPut:ATTenuation <Attenuation>
This command defines the total attenuation for RF input.
If an electronic attenuator is available and active, the command defines a mechanical attenuation (see
INPut:EATT:STATe on page 296).
If you set the attenuation manually, it is no longer coupled to the reference level, but the reference level is coupled to the attenuation. Thus, if the current reference level is not compatible with an attenuation that has been set manually, the command also adjusts the reference level.
Parameters:
<Attenuation> Range: see data sheet
Increment: 5 dB
*RST: 10 dB (AUTO is set to ON)
Example: INP:ATT 30dB
Defines a 30 dB attenuation and decouples the attenuation from the reference level.
Usage: SCPI confirmed
Manual operation: See
"Attenuation Mode / Value" on page 149
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INPut:ATTenuation:AUTO <State>
This command couples or decouples the attenuation to the reference level. Thus, when the reference level is changed, the R&S FPS determines the signal level for optimal internal data processing and sets the required attenuation accordingly.
Parameters:
<State> ON | OFF | 0 | 1
*RST: 1
Example: INP:ATT:AUTO ON
Couples the attenuation to the reference level.
Usage: SCPI confirmed
Manual operation: See
"Attenuation Mode / Value" on page 149
INPut:EATT <Attenuation>
This command defines an electronic attenuation manually. Automatic mode must be
switched off (INP:EATT:AUTO OFF, see INPut:EATT:AUTO on page 295).
If the current reference level is not compatible with an attenuation that has been set manually, the command also adjusts the reference level.
This command requires the electronic attenuation hardware option.
Parameters:
<Attenuation> attenuation in dB
Range: see data sheet
Increment: 1 dB
*RST: 0 dB (OFF)
Example: INP:EATT:AUTO OFF
INP:EATT 10 dB
Manual operation: See
"Using Electronic Attenuation" on page 150
INPut:EATT:AUTO <State>
This command turns automatic selection of the electronic attenuation on and off.
If on, electronic attenuation reduces the mechanical attenuation whenever possible.
This command requires the electronic attenuation hardware option.
Parameters:
<State> ON | OFF | 0 | 1
*RST: 1
Example: INP:EATT:AUTO OFF
Manual operation: See
"Using Electronic Attenuation" on page 150
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INPut:EATT:STATe <State>
This command turns the electronic attenuator on and off.
This command requires the electronic attenuation hardware option.
Parameters:
<State> ON | OFF
*RST: OFF
Example: INP:EATT:STAT ON
Switches the electronic attenuator into the signal path.
Manual operation: See
"Using Electronic Attenuation" on page 150
11.5.2.6
Scaling and Units
Useful commands for scaling described elsewhere:
●
DISPlay[:WINDow<n>]:TRACe<t>:Y[:SCALe]:AUTO ONCE on page 330
●
DISPlay[:WINDow<n>]:TRACe<t>:X[:SCALe]:VOFFset on page 317
Remote commands exclusive to scaling and units:
CALCulate<n>:STATistics:PRESet
This command sets the x- and y-axis of the statistics measurement to measurement dependent default values.
Usage: Event
Manual operation: See
"Default Settings" on page 153
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CALCulate<n>:STATistics:SCALe:AUTO ONCE
This command initiates an automatic scaling of the diagram (x- and y-axis).
To obtain maximum resolution, the level range is set as a function of the measured spacing between peak power and the minimum power for the APD measurement and of the spacing between peak power and mean power for the CCDF measurement. In addition, the probability scale for the number of test points is adapted.
To get valid results, you have to perform a complete sweep with synchronization to the end of the auto range process. This is only possible in single sweep mode.
Parameters:
ONCE
Example:
Usage:
CALC:STAT:SCAL:AUTO ONCE;*WAI
Adapts the level setting for statistical measurements.
Event
Manual operation: See
CALCulate<n>:STATistics:SCALe:X:BCOunt <StatNofColumns>
This command defines the number of columns for the statistical distribution.
Setting parameters:
<StatNofColumns> numeric value
Range:
*RST:
2 to 1024
101
Default unit: NONE
Manual operation: See
CALCulate<n>:STATistics:SCALe:Y:LOWer <Magnitude>
This command defines the lower vertical limit of the diagram.
Parameters:
<Magnitude> The number is a statistical value and therefore dimensionless.
Range:
*RST:
1E-9 to 0.1
1E-6
Example: CALC:STAT:SCAL:Y:LOW 0.001
Manual operation: See
"Defining Min and Max Values" on page 152
CALCulate<n>:STATistics:SCALe:Y:UPPer <Magnitude>
This command defines the upper vertical limit of the diagram.
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Parameters:
<Magnitude> The number is a statistical value and therefore dimensionless.
Range:
*RST:
1E-5 to 1.0
1.0
Example: CALC:STAT:SCAL:Y:UPP 0.01
Manual operation: See
"Defining Min and Max Values" on page 152
CALCulate<n>:STATistics:SCALe:Y:UNIT <Unit>
This command selects the unit of the y-axis.
Parameters:
<Unit> PCT | ABS
*RST: ABS
Example: CALC:STAT:SCAL:Y:UNIT PCT
Sets the percentage scale.
Manual operation: See
CALCulate<n>:UNIT:ANGLe <Unit>
This command selects the global unit for phase results.
Setting parameters:
<Unit> DEG | RAD
*RST: RAD
Manual operation: See
CALCulate<n>:X:UNIT:TIME <Unit>
This command selects the unit (symbols or seconds) for the x axis.
Setting parameters:
<Unit> S | SYM
*RST: SYM
Manual operation: See
CALCulate<n>:Y:UNIT:TIME <Unit>
This command selects the unit (symbols or seconds) for the y axis of equalizer group delay measurements.
Setting parameters:
<Unit> S | SYM
*RST: SYM
Manual operation: See
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DISPlay[:WINDow<n>]:TRACe<t>:X[:SCALe]:PDIVision <PDiv>
This command defines the scaling of the x-axis for statistical result displays.
For all other result displays, this command is only available as a query.
Setting parameters:
<PDiv> numeric value
Defines the range per division (total range = 10*<PDiv>)
Manual operation: See
"Range per Division" on page 153
DISPlay[:WINDow<n>]:TRACe<t>:X[:SCALe]:RPOSition <RPos>
This command defines the position of the reference value for the X axis.
Setting the position of the reference value is possible only for statistical result displays.
All other result displays support the query only.
Setting parameters:
<RPos> numeric value
<numeric_value>
Example: DISP:TRAC:X:RPOS 30 PCT
The reference value is shifted by 30% towards the left.
Manual operation: See
"X-Axis Reference Position" on page 153
DISPlay[:WINDow<n>]:TRACe<t>:X[:SCALe]:RVALue <RVal>
This command defines the reference value for the x-axis for statistical result displays.
For all other result displays, this command is only available as a query.
Setting parameters:
<RVal> numeric value
Reference value for the x-axis
Manual operation: See
"X-Axis Reference Value" on page 153
DISPlay[:WINDow<n>]:TRACe<t>:Y[:SCALe] <Range>
This command defines the display range of the y-axis (for all traces, <t> is irrelevant).
Example:
Usage:
DISP:TRAC:Y 110dB
SCPI confirmed
DISPlay[:WINDow<n>]:TRACe<t>:Y[:SCALe]:PDIVision <Value>
This remote command determines the grid spacing on the Y-axis for all diagrams, where possible.
The suffix <t> is irrelevant.
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Parameters:
<Value> numeric value WITHOUT UNIT (unit according to the result display)
Defines the range per division (total range = 10*<Value>)
*RST: depends on the result display
Example: DISP:TRAC:Y:PDIV 10
Sets the grid spacing to 10 units (e.g. dB) per division
Manual operation: See
"Range per Division" on page 152
DISPlay[:WINDow<n>]:TRACe<t>:Y[:SCALe]:RPOSition <Position>
This command defines the vertical position of the reference level on the display grid
(for all traces, <t> is irrelevant).
The R&S FPS adjusts the scaling of the y-axis accordingly.
Example:
Usage:
DISP:TRAC:Y:RPOS 50PCT
SCPI confirmed
Manual operation: See
"Y-Axis Reference Position" on page 152
DISPlay[:WINDow<n>]:TRACe<t>:Y[:SCALe]:RVALue <Value>
The command defines the power value assigned to the reference position in the grid
(for all traces, <t> is irrelevant).
For external generator calibration measurements (requires the optional External Generator Control), this command defines the power offset value assigned to the reference position.
Parameters:
<Value>
Example:
*RST: 0 dBm, coupled to reference level
DISP:TRAC:Y:RVAL -20dBm
Sets the power value assigned to the reference position to -20 dBm
Manual operation: See
"Y-Axis Reference Value" on page 152
DISPlay[:WINDow<n>]:TRACe<t>:Y:SPACing <ScalingType>
This command selects the scaling of the y-axis (for all traces, <t> is irrelevant).
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Parameters:
<ScalingType>
Example:
LOGarithmic
Logarithmic scaling.
LINear
Linear scaling in %.
LDB
Linear scaling in the specified unit.
PERCent
Linear scaling in %.
*RST: LOGarithmic
DISP:TRAC:Y:SPAC LIN
Selects linear scaling in %.
Usage: SCPI confirmed
Manual operation: See
11.5.3 Signal Capture
The signal capture commands define how much, how and when data is captured from the input signal.
MSRA operating mode
In MSRA operating mode, only the MSRA Master channel actually captures data from the input signal. The data acquisition settings for the VSA application in MSRA mode define the application data extract and analysis interval.
For details on the MSRA operating mode see the R&S FPS MSRA User Manual.
The tasks for manual operation are described in
chapter 5.6, "Signal Capture" , on page 154.
[SENSe:]DDEMod:PRATe <CaptOverSmplg>
Defines the number of samples that are captured per symbol, i.e. the factor by which the symbol rate is multiplied to obtain the sample rate. This parameter also affects the demodulation bandwidth and thus the usable I/Q bandwidth.
The sample rate depends on the defined
(see chapter 4.2, "Sample Rate,
Symbol Rate and I/Q Bandwidth" , on page 63).
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Setting parameters:
<CaptOverSmplg> 4 | 8 | 16 | 32
The factor by which the symbol rate is multiplied to obtain the sample rate, e.g. 4 samples per symbol: sample rate = 4*symbol rate
*RST: 4
Manual operation: See
[SENSe:]DDEMod:RLENgth:AUTO <RecLengthAuto>
If enabled, the capture length is automatically adapted as required according to the current result length, burst and pattern search settings, and network-specific characteristics (e.g. burst and frame structures).
Setting parameters:
<RecLengthAuto> ON | OFF | 1 | 0
*RST: 1
Manual operation: See
"Capture Length Settings" on page 156
[SENSe:]DDEMod:RLENgth[:VALue] <RecordLength>
This command defines the capture length for further processing, e.g. for burst search.
The record length is defined in time (S, default) or symbols (SYM).
Note that the maximum record length depends on the sample rate for signal capture
(see [SENSe:]DDEMod:PRATe on page 301). For the default value =4, the maximum
is 64000 symbols. For larger sample rates, the maximum record length (in symbols) can be calculated as:
Recordlength
MAX
= 256000/ <points per symbol>
Setting parameters:
<RecordLength> numeric value
*RST: 2.083 ms
Default unit: s (not symbols as in manual operation!)
Example: See
chapter 11.13.2, "Measurement Example 2: GSM EDGE
Burst Measurement Based on a Digital Standard" , on page 405
Manual operation: See
"Capture Length Settings" on page 156
[SENSe:]SWAPiq <State>
This command defines whether or not the recorded IQ pairs should be swapped (I<-
>Q) before being processed. Swapping I and Q inverts the sideband.
This is useful if the DUT interchanged the I and Q parts of the signal; then the
R&S FPS can do the same to compensate for it.
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Parameters:
<State> ON
I and Q signals are interchanged
Inverted sideband, Q+j*I
OFF
I and Q signals are not interchanged
Normal sideband, I+j*Q
*RST: OFF
Manual operation: See
TRACe<n>:IQ:BWIDth?
This command queries the bandwidth in Hz of the resampling filter ("Usable I/Q Bandwidth").
Usage: Query only
Manual operation: See
"Usable I/Q Bandwidth" on page 156
11.5.4 Triggering Measurements
The trigger commands define the beginning of a measurement.
MSRA operating mode
In MSRA operating mode, only the MSRA Master channel actually captures data from the input signal. Thus, no trigger settings are available in the VSA application in MSRA operating mode. However, a capture offset can be defined with a similar effect as a trigger offset. It defines an offset from the start of the captured data (from the MSRA
Master) to the start of the application data for vector signal analysis. (See
Configuring an Analysis Interval and Line (MSRA mode only) .)
For details on the MSRA operating mode see the R&S FPS MSRA User Manual.
Tasks for manual configuration are described in chapter 5.6.2, "Trigger Settings" , on page 157.
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TRIGger[:SEQuence]:DTIMe <DropoutTime>
Defines the time the input signal must stay below the trigger level before a trigger is detected again.
Parameters:
<DropoutTime> Dropout time of the trigger.
Range:
*RST:
0 s to 10.0 s
0 s
Manual operation: See
TRIGger[:SEQuence]:HOLDoff[:TIME] <Offset>
Defines the time offset between the trigger event and the start of the measurement.
Parameters:
<Offset>
Example:
The allowed range is 0 s to 30 s.
*RST: 0 s
TRIG:HOLD 500us
Manual operation: See
TRIGger[:SEQuence]:IFPower:HOLDoff <Period>
This command defines the holding time before the next trigger event.
Note that this command can be used for any trigger source, not just IF Power
(despite the legacy keyword).
Note: If you perform gated measurements in combination with the IF Power trigger, the
R&S FPS ignores the holding time for frequency sweep, FFT sweep, zero span and I/Q data measurements.
Parameters:
<Period> Range:
*RST:
0 s to 10 s
0 s
Example: TRIG:SOUR EXT
Sets an external trigger source.
TRIG:IFP:HOLD 200 ns
Sets the holding time to 200 ns.
Manual operation: See
TRIGger[:SEQuence]:IFPower:HYSTeresis <Hysteresis>
This command defines the trigger hysteresis, which is only available for "IF Power" trigger sources.
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Configuring VSA
Parameters:
<Hysteresis> Range:
*RST:
3 dB to 50 dB
3 dB
Example: TRIG:SOUR IFP
Sets the IF power trigger source.
TRIG:IFP:HYST 10DB
Sets the hysteresis limit value.
Manual operation: See
TRIGger[:SEQuence]:LEVel[:EXTernal<port>] <TriggerLevel>
This command defines the level the external signal must exceed to cause a trigger event.
Suffix:
<port>
.
Selects the trigger port.
1 = trigger port 1 (TRIG IN connector on rear panel)
2 = trigger port 2 (TRIG AUX connector on rear panel)
Parameters:
<TriggerLevel> Range:
*RST:
0.5 V to 3.5 V
1.4 V
Example: TRIG:LEV 2V
Manual operation: See
TRIGger[:SEQuence]:LEVel:IFPower <TriggerLevel>
This command defines the power level at the third intermediate frequency that must be exceeded to cause a trigger event. Note that any RF attenuation or preamplification is considered when the trigger level is analyzed. If defined, a reference level offset is also considered.
Parameters:
<TriggerLevel> For details on available trigger levels and trigger bandwidths see the data sheet.
*RST: -10 dBm
Example: TRIG:LEV:IFP -30DBM
Manual operation: See
TRIGger[:SEQuence]:LEVel:IQPower <TriggerLevel>
This command defines the magnitude the I/Q data must exceed to cause a trigger event. Note that any RF attenuation or preamplification is considered when the trigger level is analyzed.
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Parameters:
<TriggerLevel> Range:
*RST:
-130 dBm to 30 dBm
-20 dBm
Example: TRIG:LEV:IQP -30DBM
Manual operation: See
Remote Commands for VSA
Configuring VSA
TRIGger[:SEQuence]:SLOPe <Type>
For all trigger sources except time you can define whether triggering occurs when the signal rises to the trigger level or falls down to it.
Parameters:
<Type> POSitive | NEGative
POSitive
Triggers when the signal rises to the trigger level (rising edge).
NEGative
Triggers when the signal drops to the trigger level (falling edge).
*RST: POSitive
Example: TRIG:SLOP NEG
Manual operation: See
TRIGger[:SEQuence]:SOURce <Source>
This command selects the trigger source.
Note on external triggers:
If a measurement is configured to wait for an external trigger signal in a remote control program, remote control is blocked until the trigger is received and the program can continue. Make sure this situation is avoided in your remote control programs.
Parameters:
<Source> IMMediate
Free Run
EXTernal
Trigger signal from the TRIGGER IN connector.
EXT2
Trigger signal from the TRIGGER AUX connector.
RFPower
First intermediate frequency
IFPower
Second intermediate frequency
IQPower
Magnitude of sampled I/Q data
For applications that process I/Q data, such as the I/Q Analyzer or optional applications.
*RST: IMMediate
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Configuring VSA
Example: TRIG:SOUR EXT
Selects the external trigger input as source of the trigger signal
Manual operation: See
See
See
"External Trigger 1/2" on page 159
See
See
11.5.5 Configuring Sweeps
The sweep commands define how often data from the input signal is acquired and then evaluated.
Manual configuration of the sweeps is described in chapter 5.6.3, "Sweep Settings" , on page 161.
[SENSe:]DDEMod:SEARch:MBURst:CALC <SelResRangeNr>
Sets the result range to be displayed after a single sweep (e.g. a burst number).
Setting parameters:
<SelResRangeNr> numeric value
Range:
*RST:
1 to 1000000
1
Default unit: NONE
Example: See
chapter 11.13.2, "Measurement Example 2: GSM EDGE
Burst Measurement Based on a Digital Standard" , on page 405.
Manual operation: See
"Select Result Rng" on page 163
[SENSe:]SWEep:COUNt[:VALue] <SweepCount>
This command sets the statistics count.
For more information see
"Statistic Count" on page 162.
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Configuring VSA
Setting parameters:
<SweepCount> numeric value
0 activates "Auto" mode numeric value > 0
Activates "Manual" mode and sets the statistics count to the corresponding number.
Range: 0 to 200000
*RST: 0
Default unit: NONE
Usage: SCPI confirmed
Manual operation: See
[SENSe:]SWEep:COUNt:CURRent <Counter>
This command queries the current statistics counter value which indicates how many result ranges have been evaluated. For results that use the capture buffer as a source, the number of used capture buffers can be queried.
Setting parameters:
<Counter> CAPTure | STATistics
STATistics
Returns the number of result ranges that have been evaluated.
CAPTure
Returns the number of used capture buffers evaluated.
*RST: STATistics
11.5.6 Configuring Bursts and Patterns
The burst and pattern search settings can be configured, and new patterns can be defined.
Manual configuration of bursts and patterns is described in
chapter 5.7, "Burst and Pattern Configuration" , on page 164.
11.5.6.1
Burst Search
The burst search commands define when a burst is detected in the analyzed signal.
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Configuring VSA
[SENSe:]DDEMod:SEARch:BURSt:AUTO <AutoBurstSearch>
This command links the burst search to the type of signal. When a signal is marked as bursted, burst search is switched on automatically.
Setting parameters:
<AutoBurstSearch> AUTO | MANual
*RST: AUTO
Manual operation: See
"Enabling Burst Searches" on page 165
[SENSe:]DDEMod:SEARch:BURSt:CONFigure:AUTO <AutoConfigure>
This command sets the search tolerance and the min gap length to their default values.
Setting parameters:
<AutoConfigure> ON | OFF | 1 | 0
*RST: 1
Manual operation: See
"Burst Configuration" on page 166
[SENSe:]DDEMod:SEARch:BURSt:GLENgth[:MINimum] <MinGapLength>
This command defines the minimum time between two bursts. A minimum time with decreased level must occur between two bursts. The default unit is symbol. The value can also be given in seconds.
Setting parameters:
<MinGapLength> numeric value
Range:
*RST:
1 to 15000
1
Default unit: SYM
Manual operation: See
[SENSe:]DDEMod:SEARch:BURSt:MODE <MeasOnlyOnBurst>
This command sets the vector analyzer so that a measurement is performed only if a burst is found. The command is available only if the burst search is activated (see
[SENSe:]DDEMod:SEARch:BURSt:STATe on page 310).
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Configuring VSA
Setting parameters:
<MeasOnlyOnBurst> MEAS | BURS
MEAS
Measurement is always performed
BURS
Measurement is performed only if a burst is found
*RST: MEAS
Manual operation: See
"Measuring only if burst was found" on page 165
[SENSe:]DDEMod:SEARch:BURSt:STATe <SearchState>
This command switches the search for a signal burst on or off.
Setting parameters:
<SearchState> ON | OFF | 1 | 0
*RST: 0
[SENSe:]DDEMod:SEARch:BURSt:TOLerance <SearchTolerance>
This command controls burst search tolerance.
Setting parameters:
<SearchTolerance> numeric value
Range:
*RST:
0 to 100000
4
Default unit: SYM
Manual operation: See
"Search Tolerance" on page 166
11.5.6.2
Pattern Searches
The pattern search commands define when a pattern is detected in the analyzed signal.
[SENSe:]DDEMod:SEARch:PATTern:CONFigure:AUTO ....................................................310
[SENSe:]DDEMod:SEARch:PATTern:CONFigure:AUTO <AutoConfigure>
This command sets the IQ correlation threshold to its default value.
Setting parameters:
<AutoConfigure> ON | OFF | 1 | 0
*RST: 1
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Configuring VSA
Manual operation: See
"I/Q Correlation Threshold" on page 167
[SENSe:]DDEMod:SEARch:SYNC:AUTO <AutoPattSearch>
This command links the pattern search to the type of signal. When a signal is marked as patterned, pattern search is switched on automatically.
Setting parameters:
<AutoPattSearch> AUTO | MANual
*RST: AUTO
Manual operation: See
"Enabling Pattern Searches" on page 167
[SENSe:]DDEMod:SEARch:SYNC:IQCThreshold <CorrelationLev>
This command sets the IQ correlation threshold for pattern matching in percent. A high level means stricter matching.
Setting parameters:
<CorrelationLev> numeric value
Range:
*RST:
10.0 to 100.0
90.0
Default unit: PCT
Manual operation: See
"I/Q Correlation Threshold" on page 167
[SENSe:]DDEMod:SEARch:SYNC:MODE <MeasOnlyOnPatt>
This command sets the vector analyzer so that the measurement is performed only if the measurement was synchronous to the selected sync pattern.
The command is available only if the pattern search is activated (see [SENSe:
]DDEMod:SEARch:SYNC:STATe on page 312).
Setting parameters:
<MeasOnlyOnPatt> MEAS | SYNC
MEAS
The measurement is performed independently of successful synchronization
SYNC
The measured values are displayed and considered in the error evaluation only if the set sync pattern was found. Bursts with a wrong sync pattern (sync not found) are ignored. If an invalid or no sync pattern is found, the measurement waits and resumes running only when a valid sync pattern is found.
*RST: 0
Manual operation: See
"Meas only if Pattern Symbols Correct" on page 168
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Configuring VSA
[SENSe:]DDEMod:SEARch:SYNC:SELect <Select>
This command selects a predefined sync pattern file.
Setting parameters:
<Select> string
Example: See
chapter 11.13.3, "Measurement Example 3: User-Defined
Pattern Search and Limit Check" , on page 409.
Manual operation: See
"Selected Pattern for Search" on page 168
See
"Standard Patterns - selecting an assigned pattern" on page 169
[SENSe:]DDEMod:SEARch:SYNC:STATe <PatternSearch>
This command switches the search for a sync sequence on or off.
Setting parameters:
<PatternSearch> ON | OFF | 1 | 0
*RST: 0
Manual operation: See
"Enabling Pattern Searches" on page 167
See
"Pattern Search On" on page 171
11.5.6.3
Configuring Patterns
New patterns can be defined and assigned to a signal standard.
Useful commands for configuring patterns described elsewhere:
●
[SENSe:]DDEMod:SEARch:SYNC:STATe on page 312
●
[SENSe:]DDEMod:SEARch:SYNC:CATalog on page 286
Remote commands exclusive to configuring patterns:
[SENSe:]DDEMod:SEARch:SYNC:COMMent <Comment>
This command defines a comment to a sync pattern. The pattern must have been selected before using
[SENSe:]DDEMod:SEARch:SYNC:NAME on page 314.
Setting parameters:
<Comment> string
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Configuring VSA
Example: See
chapter 11.13.3, "Measurement Example 3: User-Defined
Pattern Search and Limit Check" , on page 409.
Manual operation: See
See
See
[SENSe:]DDEMod:SEARch:SYNC:COPY <Pattern>
This command copies a pattern file. The pattern to be copied must have been selected before using
[SENSe:]DDEMod:SEARch:SYNC:NAME on page 314.
Tip: In manual operation, a pattern can be copied in the editor by storing it under a new name.
Setting parameters:
<Pattern> string
Example: :DDEM:SEAR:SYNC:NAME 'GSM_TSC0'
Selects the pattern.
:DDEM:SEAR:SYNC:COPY 'GSM_PATT'
Copies "GSM_TSC0" to GSM_PATT.
Usage: Setting only
Manual operation: See
[SENSe:]DDEMod:SEARch:SYNC:DELete
This command deletes a sync sequence. The sync sequence to be deleted must have
been selected before using [SENSe:]DDEMod:SEARch:SYNC:NAME on page 314.
Usage: Event
Manual operation: See
[SENSe:]DDEMod:SEARch:SYNC:DATA <Data>
This command defines the sync sequence of a sync pattern. The pattern must have
been selected before using [SENSe:]DDEMod:SEARch:SYNC:NAME on page 314.
Important: The value range of a symbol depends on the degree of modulation,e.g. for an 8PSK modulation the value range is from 0 to 7. The degree of modulation belongs to the pattern and is set using the DDEM:SEAR:SYNC:NST command (see
]DDEMod:SEARch:SYNC:NSTate on page 314).
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Configuring VSA
Setting parameters:
<Data> string
Four values represent a symbol (hexadecimal format). The value range of a symbol depends on the degree of modulation.
With a degree of modulation of 4, all symbols have a value range of: 0000, 0001, 0002, 0003
With a degree of modulation of 8:
0000, 0001, 0002, 0003, 0004, 0005, 0006, 0007
Example:
Example:
DDEM:SEAR:SYNC:DATA '00010000FFFF'
Defines the pattern data.
See
chapter 11.13.3, "Measurement Example 3: User-Defined
Pattern Search and Limit Check" , on page 409.
Manual operation: See
See
See
[SENSe:]DDEMod:SEARch:SYNC:NAME <Name>
This command selects a sync pattern for editing or for a new entry.
Setting parameters:
<Name> string
Example: See
chapter 11.13.3, "Measurement Example 3: User-Defined
Pattern Search and Limit Check" , on page 409.
Manual operation: See
See
See
[SENSe:]DDEMod:SEARch:SYNC:NSTate <NState>
This command selects the degree of modulation (number of permitted states). The pattern must have been selected before using using
The number of permitted states depends on the modulation mode.
Setting parameters:
<NState> numeric value
Example: See
chapter 11.13.3, "Measurement Example 3: User-Defined
Pattern Search and Limit Check" , on page 409.
Manual operation: See
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Configuring VSA
[SENSe:]DDEMod:SEARch:SYNC:PATTern:ADD <AddPattern>
This command adds a pattern to the current standard. Using the
DDEM:SEAR:SYNC:SEL command, only those patterns can be selected which belong to the current standard (see
[SENSe:]DDEMod:SEARch:SYNC:SELect on page 312).
Setting parameters:
<AddPattern> string
Example: See
chapter 11.13.3, "Measurement Example 3: User-Defined
Pattern Search and Limit Check" , on page 409.
Usage: Setting only
Manual operation: See
"Adding patterns to a standard" on page 170
[SENSe:]DDEMod:SEARch:SYNC:PATTern:REMove
This command deletes one or all patterns from the current standard.
Usage: Setting only
Manual operation: See
"Removing patterns from a standard" on page 170
[SENSe:]DDEMod:SEARch:SYNC:TEXT <Text>
This command defines a text to explain the pattern. The text is displayed only in the selection menu (manual control). This text should be short and concise. Detailed information about the pattern is given in the comment (see
Setting parameters:
<Text> string
Example: See
chapter 11.13.3, "Measurement Example 3: User-Defined
Pattern Search and Limit Check" , on page 409.
Manual operation: See
See
See
11.5.7 Defining the Result Range
The result range determines which part of the capture buffer, burst or pattern is displayed.
Manual configuration of the result range is described in
Useful commands for result ranges described elsewhere:
●
[SENSe:]DDEMod:SEARch:MBURst:STARt?
●
DISPlay[:WINDow<n>]:TRACe<t>:X[:SCALe]:STOP?
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Configuring VSA
Remote commands exclusive to defining result ranges:
CALCulate<n>:TRACe<t>:ADJust:ALIGnment[:DEFault] <Alignment>
This command defines where the reference point is to appear in the result range.
Suffix:
<t>
.
1..6
Setting parameters:
<Alignment> LEFT | CENTer | RIGHt
LEFT
The reference point is at the start of the result range.
CENTer
The reference point is in the middle of the result range.
RIGHt
The reference point is displayed at the end of the result range.
*RST: LEFT
Example: See
chapter 11.13.2, "Measurement Example 2: GSM EDGE
Burst Measurement Based on a Digital Standard" , on page 405.
Manual operation: See
CALCulate<n>:TRACe<t>:ADJust:ALIGnment:OFFSet <FitOffset>
This command shifts the display range (relative to the reference time) by the number of given symbols. The resolution is 1 symbol. A value >0 results in a shift towards the right, and a value <0 results in a shift towards the left.
Suffix:
<t>
.
1..6
Setting parameters:
<FitOffset> numeric value
Range:
*RST:
-8000 to 8000
0
Default unit: SYM
Example: See
chapter 11.13.2, "Measurement Example 2: GSM EDGE
Burst Measurement Based on a Digital Standard" , on page 405.
Manual operation: See
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Configuring VSA
CALCulate<n>:TRACe<t>:ADJust[:VALue] <Reference>
This command defines the reference point for the display.
Suffix:
<t>
.
1..6
Setting parameters:
<Reference> TRIGger | BURSt | PATTern
TRIGger
The reference point is defined by the start of the capture buffer.
BURSt
The reference point is defined by the start/center/end of the burst.
PATTern
The instrument selects the reference point and the alignment.
*RST: TRIGger
Example: See
chapter 11.13.2, "Measurement Example 2: GSM EDGE
Burst Measurement Based on a Digital Standard" , on page 405.
Manual operation: See
DISPlay[:WINDow<n>]:TRACe<t>:X[:SCALe]:VOFFset <VOffset>
This command defines an offset to numbering of the symbols (Except capture buffer).
Setting parameters:
<VOffset> numeric value
Range:
*RST:
-100000 to 100000
0
Default unit: NONE
Example: See
chapter 11.13.2, "Measurement Example 2: GSM EDGE
Burst Measurement Based on a Digital Standard" , on page 405.
Manual operation: See
"Symbol Number at <Reference> Start" on page 175
[SENSe:]DDEMod:TIME <ResultLength>
The command determines the number of displayed symbols (result length).
Setting parameters:
<ResultLength> numeric value
Range: 10 to 64000
*RST: 800
Default unit: SYM
Example: See
chapter 11.13.2, "Measurement Example 2: GSM EDGE
Burst Measurement Based on a Digital Standard" , on page 405.
Manual operation: See
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Configuring VSA
11.5.8 Demodulation Settings
During demodulation of the vector signal some undesired effects that may occur during transmission can be compensated for. Furthermore, you can influence the synchronization process.
..................................................................................323
[SENSe:]DDEMod:ECALc[:MODE] <EvmCalc>
This command defines the calculation formula for EVM.
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Configuring VSA
Setting parameters:
<EvmCalc> SIGNal | SYMBol | MECPower | MACPower
SIGNal
Calculation normalized to the mean power of the reference signal at the symbol instants.
SYMBol
Calculation normalized to the maximum power of the reference signal at the symbol instants.
MECPower
Calculation normalized to the mean expected power of the measurement signal at the symbol instants
MACPower
Calculation normalized to the maximum expected power of the measurement signal at the symbol instants
*RST: SIGNal
Manual operation: See
"Normalize EVM to" on page 181
[SENSe:]DDEMod:ECALc:OFFSet <EVMOffsetState>
ConfigureS the way the VSA application calculates the error vector results for offset
QPSK.
Setting parameters:
<EVMOffsetState> ON | OFF | 1 | 0
ON
VSA application compensates the delay of the Q component with respect to the I component in the measurement signal as well as the reference signal before calculating the error vector.
That means that the error vector contains only one symbol instant per symbol period.
OFF the VSA application substracts the measured signal from the reference signal to calculate the error vector. This method results in the fact that the error vector contains two symbol instants per symbol period: one that corresponds to the I component and one that corresponds to the Q component.
*RST: 1
Manual operation: See
[SENSe:]DDEMod:EPRate:AUTO <LinkMode>
Defines how many sample points are used at each symbol to calculate modulation accuracy results automatically.
If enabled, the VSA application uses the following settings, depending on the modulation type:
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Configuring VSA
Modulation
PSK, QAM
Offset QPSK
FSK, MSK
Est. Points
1
2
Sample rate (see
[SENSe:]DDEMod:PRATe on page 301)
Setting parameters:
<LinkMode> ON | OFF | 1 | 0
*RST: 1
Manual operation: See
"Estimation Points/Sym" on page 182
[SENSe:]DDEMod:EPRate[:VALue] <EstOverSmplg>
Defines how many sample points are used at each symbol to calculate modulation accuracy results.
For more information see
"Estimation points per symbol" on page 121.
You can also let the VSA application decide how many estimation points to use, see
[SENSe:]DDEMod:EPRate:AUTO on page 319.
Setting parameters:
<EstOverSmplg> 1 the estimation algorithm takes only the symbol time instants into account
2 two points per symbol instant are used (required for Offset
QPSK)
4 | 8 | 16 | 32 the number of samples per symbol defined in the signal capture settings is used (see
[SENSe:]DDEMod:PRATe on page 301),
i.e. all sample time instants are weighted equally
*RST: 1
Manual operation: See
"Estimation Points/Sym" on page 182
[SENSe:]DDEMod:EQUalizer:LENGth <FilterLength>
This command defines the length of the equalizer in terms of symbols.
Setting parameters:
<FilterLength> numeric value
Range:
*RST:
1 to 256
10
Default unit: SYM
Example: DDEM:EQU:LENG 101
Sets the equalizer length to 101 symbols.
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Configuring VSA
Manual operation: See
[SENSe:]DDEMod:EQUalizer:LOAD <Name>
This command selects a user-defined equalizer. The equalizer mode is automatically switched to USER (see
[SENSe:]DDEMod:EQUalizer:MODE on page 321).
Setting parameters:
<Name> string
Path and file name (without extension)
Example: DDEM:EQU:LOAD 'D:\MyEqualizer'
Selects equalizer named MyEqualizer in directory D.
Manual operation: See
"Store/Load Current Equalizer" on page 180
[SENSe:]DDEMod:EQUalizer:MODE <Mode>
Switches between the equalizer modes.
For details see
chapter 4.4.5, "The Equalizer" , on page 97.
Setting parameters:
<Mode> NORMal
Switches the equalizer on for the next sweep.
TRACking
Switches the equalizer on; the results of the equalizer in the previous sweep are considered to calculate the new filter.
FREeze
The filter is no longer changed, the current equalizer values are used for subsequent sweeps.
USER
A user-defined equalizer loaded from a file is used.
AVERaging
Switches the equalizer on; the results of the equalizer in all previous sweeps (since the instrument was switched on or the equalizer was reset) are considered to calculate the new filter.
To start a new averaging process, use the [SENSe:]DDEMod:
EQUalizer:RESet on page 322 command.
*RST: TRACe
Example: DDEM:EQU:MODE TRAC
Activates the tracking mode of the equalizer.
Manual operation: See
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Configuring VSA
[SENSe:]DDEMod:EQUalizer:RESet
This command deletes the data of the currently selected equalizer. After deletion, train-
ing can start again using the command DDEM:EQU:MODE TRA (see [SENSe:
]DDEMod:EQUalizer:MODE on page 321).
Usage: Event
Manual operation: See
[SENSe:]DDEMod:EQUalizer:SAVE <Name>
This command saves the current equalizer results to a file.
Setting parameters:
<Name> string
File name
Example: DDEM:EQU:SAVE 'D:\MyEqualizer''
Saves the current equalizer results to D:\MyEqualizer.vae.
Manual operation: See
"Store/Load Current Equalizer" on page 180
[SENSe:]DDEMod:EQUalizer[:STATe] <State>
This command activates or deactivates the equalizer.
For more information on the equalizer see
chapter 4.4.5, "The Equalizer" , on page 97.
Setting parameters:
<State> ON | OFF | 1 | 0
*RST: OFF
Example: DDEM:EQU OFF
Manual operation: See
[SENSe:]DDEMod:FSYNc:AUTO <FineSyncAuto>
This command selects manual or automatic Fine Sync
Setting parameters:
<FineSyncAuto> ON | OFF | 1 | 0
*RST: 1
Manual operation: See
"Fine Synchronization" on page 183
[SENSe:]DDEMod:FSYNc:LEVel <SERLevel>
This command sets the Fine Sync Level if fine sync works on Known Data
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Configuring VSA
Setting parameters:
<SERLevel> numeric value
Range:
*RST:
0.0 to 100.0
10.0
Default unit: PCT
Manual operation: See
[SENSe:]DDEMod:FSYNc:RESult?
The result of this query is 0 if the fine sync with known data failed, otherwise 1.
Usage: Query only
Manual operation: See
"Fine Synchronization" on page 183
[SENSe:]DDEMod:FSYNc[:MODE] <FineSync>
This command defines the fine synchronization mode used to calculate results, e.g. the bit error rate.
Note: You can define a maximum symbol error rate (SER) for the known data in reference to the analyzed data. If the SER of the known data exceeds this limit, the default
synchronization using the detected data is performed. See [SENSe:]DDEMod:
Setting parameters:
<FineSync> KDATa | PATTern | DDATa
KDATa
The reference signal is defined as the data sequence from the loaded Known Data file that most closely matches the measured data.
PATTern
The reference signal is estimated from the defined pattern.
This setting requires an activated pattern search, see
]DDEMod:SEARch:SYNC:STATe on page 312.
DDATa
(Default) The reference signal is estimated from the detected data.
*RST: DDATa
Manual operation: See
"Fine Synchronization" on page 183
[SENSe:]DDEMod:KDATa:STATe <KnownDataState>
This command selects the Known Data state. The use of known data is a prerequisite for the BER measurement and can also be used for the fine sync.
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Setting parameters:
<KnownDataState> ON | OFF | 1 | 0
*RST: 0
Manual operation: See
[SENSe:]DDEMod:KDATa[:NAME] <FileName>
This command selects the Known Data file
Setting parameters:
<FileName> string
Manual operation: See
Remote Commands for VSA
Configuring VSA
[SENSe:]DDEMod:NORMalize:ADRoop <CompAmptDroop>
This command switches the compensation of the amplitude droop on or off.
Setting parameters:
<CompAmptDroop> ON | OFF | 1 | 0
*RST: 1
Manual operation: See
"Compensate for... (PSK, MSK, ASK, QAM)" on page 178
[SENSe:]DDEMod:NORMalize:CFDRift <CarrFreqDrift>
This command defines whether the carrier frequency drift is compensated for FSK modulation.
Setting parameters:
<CarrFreqDrift> ON | OFF | 1 | 0
*RST: 0
Manual operation: See
"Compensate for... (FSK)" on page 179
[SENSe:]DDEMod:NORMalize:CHANnel <TransmitChannel>
This command switches the channel compensation on or off. (With equalizer only)
Setting parameters:
<TransmitChannel> ON | OFF | 1 | 0
*RST: 1
Manual operation: See
"Compensate for... (PSK, MSK, ASK, QAM)" on page 178
[SENSe:]DDEMod:NORMalize:FDERror <RefDevComp>
This command defines whether the deviation error is compensated for when calculating the frequency error for FSK modulation.
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Configuring VSA
Setting parameters:
<RefDevComp> ON | OFF | 1 | 0
ON
Scales the reference signal to the actual deviation of the measurement signal.
OFF
Uses the entered nominal deviation for the reference signal.
*RST: 1
Manual operation: See
"Compensate for... (FSK)" on page 179
[SENSe:]DDEMod:NORMalize:IQIMbalance <CompIQImbalance>
This command switches the compensation of the IQ imbalance on or off.
Setting parameters:
<CompIQImbalance> ON | OFF | 1 | 0
*RST: 0
Manual operation: See
"Compensate for... (PSK, MSK, ASK, QAM)" on page 178
[SENSe:]DDEMod:NORMalize:IQOFfset <CompIQOffset>
This command switches the compensation of the IQ offset on or off.
Setting parameters:
<CompIQOffset> ON | OFF | 1 | 0
*RST: 1
Manual operation: See
"Compensate for... (PSK, MSK, ASK, QAM)" on page 178
[SENSe:]DDEMod:NORMalize:SRERror <SymbolClockError>
This command switches the compensation for symbol rate error on or off
Setting parameters:
<SymbolClockError> ON | OFF | 1 | 0
*RST: 0
Manual operation: See
"Compensate for... (PSK, MSK, ASK, QAM)" on page 178
See
"Compensate for... (FSK)" on page 179
[SENSe:]DDEMod:OPTimization <Criterion>
This command determines the optimization criteria for the demodulation. RMSMin
Optimization goal is the minimization of RMS of the error vector. EVMMin Optimization goal is the minimization of the EVM.
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Configuring VSA
Setting parameters:
<Criterion> RMSMin | EVMMin
RMSMin
Optimizes calculation such that the RMS of the error vector is minimal.
EVMMin
Optimizes calculation such that EVM is minimal.
*RST: RMSMin (depends on selected standard)
Manual operation: See
[SENSe:]DDEMod:SEARch:PATTern:SYNC:AUTO <UseWfmForSync>
This command selects manual or automatic synchronization with a pattern waveform to speed up measurements.
Setting parameters:
<UseWfmForSync> AUTO | MANual
*RST: AUTO
Manual operation: See
"Coarse Synchronization" on page 183
[SENSe:]DDEMod:SEARch:PATTern:SYNC[:STATe] <FastSync>
This command switches fast synchronization on and off, if you manually synchronize with a waveform pattern.
Setting parameters:
<FastSync> ON | OFF | 1 | 0
*RST: 0
Manual operation: See
"Coarse Synchronization" on page 183
11.5.9 Measurement Filter Settings
You can configure the measurement filter to be used.
Manual configuration of the measurement filter is described in
chapter 5.10, "Measurement Filter Settings" , on page 185.
Useful commands for defining measurement filters described elsewhere:
●
[SENSe:]DDEMod:FILTer:ALPHa on page 277
●
[SENSe:]DDEMod:FILTer[:STATe] on page 278
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Configuring VSA
Remote commands exclusive to configuring measurement filters:
[SENSe:]DDEMod:MFILter:ALPHa <MeasFiltAlphaBT>
This command sets the alpha value of the measurement filter.
Setting parameters:
<MeasFiltAlphaBT> numeric value
Range:
*RST:
0.1 to 1.0
0.22
Default unit: NONE
Manual operation: See
[SENSe:]DDEMod:MFILter:AUTO <MeasFilterAuto>
If this command is set to "ON", the measurement filter is defined automatically depending on the transmit filter (see
[SENSe:]DDEMod:TFILter:NAME on page 283).
Setting parameters:
<MeasFilterAuto> ON | OFF | 1 | 0
*RST: ON
Manual operation: See
"Using the Transmit Filter as a Measurement Filter (Auto)" on page 186
[SENSe:]DDEMod:MFILter:NAME <Name>
This command selects a measurement filter and automatically sets its state to "ON".
Setting parameters:
<Name> Name of the measurement filter or 'User' for a user-defined filter.
An overview of available measurement filters is provided in
chapter A.3.2, "Measurement Filters" , on page 420.
Manual operation: See
[SENSe:]DDEMod:MFILter[:STATe] <MeasFilterState>
Use this command to switch the measurement filter off. To switch a measurement filter
on, use the [SENSe:]DDEMod:MFILter:NAME command.
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Configuring VSA
Setting parameters:
<MeasFilterState> ON | OFF | 1 | 0
OFF
Switches the measurement filter off.
ON
Switches the measurement filter specified by
]DDEMod:MFILter:NAME on. However, this command is not
necessary, as the
[SENSe:]DDEMod:MFILter:NAME com-
mand automatically switches the selected filter on.
*RST: 1
Manual operation: See
[SENSe:]DDEMod:MFILter:USER <FilterName>
This command selects the user-defined measurement filter.
For details on user-defined filters, see chapter 4.1.5, "Customized Filters" , on page 61.
Setting parameters:
<FilterName> Name of the user-defined filter
Example: SENS:DDEM:MFIL:NAME 'USER'
Selects user filter mode for the meas filter
ENS:DDEM:MFIL:USER 'D:\MyMeasFilter'
Selects the user-defined meas filter
Manual operation: See
See
"Load User Filter" on page 186
11.5.10 Defining the Evaluation Range
The evaluation range defines which range of the result is to be evaluated.
Manual configuration of the evaluation range is described in chapter 5.11, "Evaluation
Range Configuration" , on page 187.
CALCulate<n>:ELIN<startstop>:STATe <Auto>
This command restricts the evaluation range. The evaluation range is considered for the following display types:
● eye diagrams
● constellation diagrams
● modulation accuracy
● statistic displays
● spectrum displays
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Configuring VSA
Suffix:
<startstop>
.
1..2
irrelevant
Setting parameters:
<Auto> ON | OFF | 1 | 0
ON
The evaluation range extends from the start value defined by
CALC:ELIN1:VAL to the stop value defined by
CALC:ELIN2:VAL (see CALCulate<n>:
ELIN<startstop>[:VALue] on page 329).
OFF
The complete result area is evaluated.
*RST: OFF
Example: See
chapter 11.13.2, "Measurement Example 2: GSM EDGE
Burst Measurement Based on a Digital Standard" , on page 405.
Manual operation: See
"Evaluating the Entire Result Range" on page 188
CALCulate<n>:ELIN<startstop>[:VALue] <LeftDisp>
Defines the start and stop values for the evaluation range (see
ELIN<startstop>:STATe on page 328).
Suffix:
<startstop>
.
1..2
1: start value, 2: stop value
Setting parameters:
<LeftDisp> numeric value
Range:
*RST:
0 to 1000000
0
Default unit: SYM
Example: See
chapter 11.13.2, "Measurement Example 2: GSM EDGE
Burst Measurement Based on a Digital Standard" , on page 405.
Manual operation: See
11.5.11 Adjusting Settings Automatically
Some settings can be adjusted by the R&S FPS automatically according to the current measurement settings.
Manual execution of automatic adjustment functions is described in
"Adjusting Settings Automatically" , on page 188.
DISPlay[:WINDow<n>]:TRACe<t>:Y[:SCALe]:AUTO ONCE ............................................... 330
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Configuring VSA
DISPlay[:WINDow<n>]:TRACe<t>:Y[:SCALe]:AUTO ONCE
Automatic scaling of the y-axis is performed once, then switched off again (for all traces, <t> is irrelevant).
Usage: SCPI confirmed
Manual operation: See
"Auto Scale Once/Auto Scale Window" on page 151
DISPlay[:WINDow<n>]:TRACe<t>:Y[:SCALe]:AUTO:ALL
Automatic scaling of the y-axis is performed once in all windows, then switched off again.
Usage: Event
Manual operation: See
[SENSe:]ADJust:CONFigure:DURation <Duration>
In order to determine the ideal reference level, the R&S FPS performs a measurement on the current input data. This command defines the length of the measurement if
[SENSe:]ADJust:CONFigure:DURation:MODE
is set to MANual.
Parameters:
<Duration> Numeric value in seconds
Range:
*RST:
Default unit: s
0.001 to 16000.0
0.001
Example: ADJ:CONF:DUR:MODE MAN
Selects manual definition of the measurement length.
ADJ:CONF:LEV:DUR 5ms
Length of the measurement is 5 ms.
Manual operation: See
"Changing the Automatic Measurement Time (Meastime
[SENSe:]ADJust:CONFigure:DURation:MODE <Mode>
In order to determine the ideal reference level, the R&S FPS performs a measurement on the current input data. This command selects the way the R&S FPS determines the length of the measurement .
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Configuring VSA
Parameters:
<Mode> AUTO
The R&S FPS determines the measurement length automatically according to the current input data.
MANual
The R&S FPS uses the measurement length defined by
[SENSe:]ADJust:CONFigure:DURation on page 330.
*RST: AUTO
Manual operation: See
"Resetting the Automatic Measurement Time (Meastime
See
"Changing the Automatic Measurement Time (Meastime
[SENSe:]ADJust:CONFigure:HYSTeresis:LOWer <Threshold>
When the reference level is adjusted automatically using the
LEVel on page 332 command, the internal attenuators and the preamplifier are also
adjusted. In order to avoid frequent adaptation due to small changes in the input signal, you can define a hysteresis. This setting defines a lower threshold the signal must fall below (compared to the last measurement) before the reference level is adapted automatically.
Parameters:
<Threshold>
Example:
Range:
*RST:
0 dB to 200 dB
+1 dB
Default unit: dB
SENS:ADJ:CONF:HYST:LOW 2
For an input signal level of currently 20 dBm, the reference level will only be adjusted when the signal level falls below 18 dBm.
Manual operation: See
"Lower Level Hysteresis" on page 189
[SENSe:]ADJust:CONFigure:HYSTeresis:UPPer <Threshold>
Parameters:
<Threshold> Range:
*RST:
0 dB to 200 dB
+1 dB
Default unit: dB
Example:
Example:
SENS:ADJ:CONF:HYST:UPP 2
For an input signal level of currently 20 dBm, the reference level will only be adjusted when the signal level rises above 22 dBm.
Manual operation: See
"Upper Level Hysteresis" on page 189
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Performing a Measurement
[SENSe:]ADJust:LEVel
[SENSe:]DDEMod:PRESet:RLEVel
This command initiates a measurement that evaluates and sets the ideal reference level for the current measurement. This ensures that the settings of the RF attenuation and the reference level are optimally adjusted to the signal level without overloading the R&S FPS or limiting the dynamic range by an S/N ratio that is too small.
Usage: Event
11.6 Performing a Measurement
When the VSA application is activated, a continuous sweep is performed automatically.
However, you can stop and start a new measurement any time.
Furthermore, you can perform a sequence of measurements using the Sequencer (see
"Multiple Measurement Channels and Sequencer Function" on page 11).
ABORt
This command aborts the measurement in the current measurement channel and resets the trigger system.
To prevent overlapping execution of the subsequent command before the measurement has been aborted successfully, use the *OPC? or *WAI command after ABOR and before the next command.
For details see the "Remote Basics" chapter in the R&S FPS User Manual.
To abort a sequence of measurements by the Sequencer, use the INITiate<n>:
command.
Note on blocked remote control programs:
If a sequential command cannot be completed, for example because a triggered sweep never receives a trigger, the remote control program will never finish and the remote channel to the R&S FPS is blocked for further commands. In this case, you must interrupt processing on the remote channel first in order to abort the measurement.
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Performing a Measurement
To do so, send a "Device Clear" command from the control instrument to the R&S FPS on a parallel channel to clear all currently active remote channels. Depending on the used interface and protocol, send the following commands:
● Visa: viClear()
Now you can send the ABORt command on the remote channel performing the measurement.
Example: ABOR;:INIT:IMM
Aborts the current measurement and immediately starts a new one.
Example: ABOR;*WAI
INIT:IMM
Aborts the current measurement and starts a new one once abortion has been completed.
Usage: Event
SCPI confirmed
INITiate<n>:CONMeas
This command restarts a (single) measurement that has been stopped (using ABORt) or finished in single measurement mode.
The measurement is restarted at the beginning, not where the previous measurement was stopped.
As opposed to INITiate<n>[:IMMediate]
, this command does not reset traces in maxhold, minhold or average mode. Therefore it can be used to continue measurements using maxhold or averaging functions.
Suffix:
<n>
Usage:
.
irrelevant
Event
Manual operation: See
"Continue Single Sweep" on page 162
INITiate<n>:CONTinuous <State>
This command controls the measurement mode for an individual measurement channel.
Note that in single measurement mode, you can synchronize to the end of the measurement with *OPC, *OPC? or *WAI. In continuous measurement mode, synchronization to the end of the measurement is not possible. Thus, it is not recommended that you use continuous measurement mode in remote control, as results like trace data or markers are only valid after a single measurement end synchronization.
For details on synchronization see the "Remote Basics" chapter in the R&S FPS User
Manual.
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Performing a Measurement
If the measurement mode is changed for a measurement channel while the Sequencer is active (see
INITiate<n>:SEQuencer:IMMediate on page 336) the mode is
only considered the next time the measurement in that channel is activated by the
Sequencer.
Suffix:
<n>
Parameters:
<State>
.
irrelevant
ON | OFF | 0 | 1
ON | 1
Continuous measurement
OFF | 0
Single measurement
*RST: 0
Example: INIT:CONT OFF
Switches the measurement mode to single measurement.
INIT:CONT ON
Switches the measurement mode to continuous measurement.
Manual operation: See
"Continuous Sweep/RUN CONT" on page 161
INITiate<n>[:IMMediate]
This command starts a (single) new measurement.
For a statistics count > 0, this means a restart of the corresponding number of measurements. With trace mode MAXHold, MINHold and AVERage, the previous results are reset on restarting the measurement.
You can synchronize to the end of the measurement with *OPC, *OPC? or *WAI.
For details on synchronization see the "Remote Basics" chapter in the R&S FPS User
Manual.
Suffix:
<n>
.
irrelevant
Usage: Event
Manual operation: See
"Single Sweep/ RUN SINGLE" on page 162
INITiate:REFMeas
Repeats the evaluation of the data currently in the capture buffer without capturing new data. This is useful after changing settings, for example filters, patterns or evaluation ranges.
Usage: Event
Manual operation: See
"Refresh (non-Multistandard mode)" on page 162
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Performing a Measurement
INITiate<n>:REFResh
This function is only available if the Sequencer is deactivated (
) and only for applications in MSRA mode, not the MSRA Master.
The data in the capture buffer is re-evaluated by the currently active application only.
The results for any other applications remain unchanged.
(The suffix <n> is irrelevant.)
Example: SYST:SEQ:OFF
Deactivates the scheduler
INIT:CONT OFF
Switches to single sweep mode.
INIT;*WAI
Starts a new data measurement and waits for the end of the sweep.
INST:SEL 'IQ ANALYZER'
Selects the IQ Analyzer channel.
INIT:REFR
Refreshes the display for the I/Q Analyzer channel.
Usage: Event
Manual operation: See
INITiate<n>:SEQuencer:REFResh[:ALL]
This function is only available if the Sequencer is deactivated (
) and only in MSRA mode.
The data in the capture buffer is re-evaluated by all active MSRA applications.
(The suffix <n> is irrelevant.)
Example:
Usage:
SYST:SEQ:OFF
Deactivates the scheduler
INIT:CONT OFF
Switches to single sweep mode.
INIT;*WAI
Starts a new data measurement and waits for the end of the sweep.
INIT:SEQ:REFR
Refreshes the display for all channels.
Event
INITiate<n>:SEQuencer:ABORt
This command stops the currently active sequence of measurements. The Sequencer itself is not deactivated, so you can start a new sequence immediately using
INITiate<n>:SEQuencer:IMMediate on page 336.
To deactivate the Sequencer use SYSTem:SEQuencer on page 337.
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Performing a Measurement
Suffix:
<n>
Usage:
.
irrelevant
Event
INITiate<n>:SEQuencer:IMMediate
This command starts a new sequence of measurements by the Sequencer.
Its effect is similar to the INITiate<n>[:IMMediate]
command used for a single measurement.
Before this command can be executed, the Sequencer must be activated (see
SYSTem:SEQuencer on page 337).
Suffix:
<n>
Example:
.
irrelevant
SYST:SEQ ON
Activates the Sequencer.
INIT:SEQ:MODE SING
Sets single sequence mode so each active measurement will be performed once.
INIT:SEQ:IMM
Starts the sequential measurements.
Usage: Event
INITiate<n>:SEQuencer:MODE <Mode>
This command selects the way the R&S FPS application performs measurements sequentially.
Before this command can be executed, the Sequencer must be activated (see
SYSTem:SEQuencer on page 337).
A detailed programming example is provided in the "Operating Modes" chapter in the
R&S FPS User Manual.
Note: In order to synchronize to the end of a sequential measurement using *OPC,
*OPC? or *WAI you must use SINGle Sequence mode.
For details on synchronization see the "Remote Basics" chapter in the R&S FPS User
Manual.
Suffix:
<n>
.
irrelevant
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Performing a Measurement
Parameters:
<Mode>
Example:
SINGle
Each measurement is performed once (regardless of the channel's sweep mode), considering each channels' sweep count, until all measurements in all active channels have been performed.
CONTinuous
The measurements in each active channel are performed one after the other, repeatedly (regardless of the channel's sweep mode), in the same order, until the Sequencer is stopped.
CDEFined
First, a single sequence is performed. Then, only those channels in continuous sweep mode (INIT:CONT ON) are repeated.
*RST: CONTinuous
SYST:SEQ ON
Activates the Sequencer.
INIT:SEQ:MODE SING
Sets single sequence mode so each active measurement will be performed once.
INIT:SEQ:IMM
Starts the sequential measurements.
SYSTem:SEQuencer <State>
This command turns the Sequencer on and off. The Sequencer must be active before any other Sequencer commands (INIT:SEQ...) are executed, otherwise an error will occur.
A detailed programming example is provided in the "Operating Modes" chapter in the
R&S FPS User Manual.
Parameters:
<State> ON | OFF | 0 | 1
ON | 1
The Sequencer is activated and a sequential measurement is started immediately.
OFF | 0
The Sequencer is deactivated. Any running sequential measurements are stopped. Further Sequencer commands (INIT:
SEQ...) are not available.
*RST: 0
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Example:
Remote Commands for VSA
Analysis
SYST:SEQ ON
Activates the Sequencer.
INIT:SEQ:MODE SING
Sets single Sequencer mode so each active measurement will be performed once.
INIT:SEQ:IMM
Starts the sequential measurements.
SYST:SEQ OFF
11.7 Analysis
General result analysis settings concerning the trace, markers, windows etc. can be configured.
● Configuring an Analysis Interval and Line (MSRA mode only) ............................. 354
11.7.1 Configuring Traces
The trace settings determine how the measured data is analyzed and displayed on the screen. Depending on the result display, between 1 and 6 traces may be displayed.
Manual configuration of traces is described in chapter 6.1, "Trace Settings" , on page 190.
Commands for storing trace data are described in
chapter 11.9.1, "Retrieving Trace
Data and Marker Values" , on page 371.
Useful commands for trace configuration described elsewhere:
●
DISPlay[:WINDow<n>]:TRACe<t>:Y[:SCALe] on page 299
Remote commands exclusive to trace configuration:
CALCulate<n>:TRACe<t>[:VALue] <TrRefType>
This commands selects the signal to be used as the data source for a trace.
Suffix:
<t>
.
1..6
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Analysis
Setting parameters:
<TrRefType> MEAS
Measurement signal
REF
Reference signal
*RST: Depends on the current measurement.
Usage: SCPI confirmed
Manual operation: See
DISPlay[:WINDow<n>]:TRACe<t>:MODE <Mode>
This command selects the trace mode.
In case of max hold, min hold or average trace mode, you can set the number of single
measurements with [SENSe:]SWEep:COUNt[:VALue]
. Note that synchronization to the end of the measurement is possible only in single sweep mode. Depending on the result display, not all trace modes may be available.
Parameters:
<Mode> WRITe
Overwrite mode: the trace is overwritten by each sweep. This is the default setting.
AVERage
The average is formed over several sweeps. The "Sweep/Average Count" determines the number of averaging procedures.
MAXHold
The maximum value is determined over several sweeps and displayed. The R&S FPS saves the sweep result in the trace memory only if the new value is greater than the previous one.
MINHold
The minimum value is determined from several measurements and displayed. The R&S FPS saves the sweep result in the trace memory only if the new value is lower than the previous one.
VIEW
The current contents of the trace memory are frozen and displayed.
BLANk
Hides the selected trace.
*RST: Trace 1: WRITe, Trace 2-6: BLANk
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Analysis
Example: INIT:CONT OFF
Switching to single sweep mode.
SWE:COUN 16
Sets the number of measurements to 16.
DISP:TRAC3:MODE WRIT
Selects clear/write mode for trace 3.
INIT;*WAI
Starts the measurement and waits for the end of the measurement.
Manual operation: See
DISPlay[:WINDow<n>]:TRACe<t>[:STATe] <State>
This command turns a trace on and off.
The measurement continues in the background.
Parameters:
<State>
Example:
ON | OFF | 0 | 1
*RST: 1 for TRACe1, 0 for TRACe 2 to 6
DISP:TRAC3 ON
Usage: SCPI confirmed
Manual operation: See
"Trace 1/Trace 2/Trace 3/Trace 4/Trace 5/Trace 6" on page 191
See
"Trace 1/Trace 2/Trace 3/Trace 4 (Softkeys)" on page 192
11.7.2 Working with Markers
Markers help you analyze your measurement results by determining particular values in the diagram. Thus you can extract numeric values from a graphical display.
Manual configuration of markers is described in
chapter 6.3, "Markers" , on page 194.
11.7.2.1
Individual Marker Settings
In VSA evaluations, up to 5 markers can be activated in each diagram at any time.
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Analysis
CALCulate<n>:DELTamarker<m>:Y?
...............................................................................343
CALCulate<n>:MARKer<m>:AOFF
This command turns all markers off.
Example: CALC:MARK:AOFF
Switches off all markers.
Usage: Event
Manual operation: See
CALCulate<n>:MARKer<m>:LINK <MarkerCoupling>
With this command markers between several screens can be coupled, i.e. use the same x-value. All screens can be linked with the marker x-value scaled in symbols or time, except those showing the capture buffer. If several capture buffer measurements are visible, their markers are coupled, too.
Setting parameters:
<MarkerCoupling> ON | OFF | 1 | 0
*RST: 0
Manual operation: See
CALCulate<n>:MARKer<m>[:STATe] <State>
This command turns markers on and off. If the corresponding marker number is currently active as a deltamarker, it is turned into a normal marker.
Parameters:
<State>
Example:
ON | OFF
*RST: OFF
CALC:MARK3 ON
Switches on marker 3.
Manual operation: See
See
CALCulate<n>:MARKer<m>:TRACe <Trace>
This command selects the trace the marker is positioned on.
Note that the corresponding trace must have a trace mode other than "Blank".
If necessary, the command activates the marker first.
Parameters:
<Trace> 1 to 6
Trace number the marker is assigned to.
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Example: CALC:MARK3:TRAC 2
Assigns marker 3 to trace 2.
Manual operation: See
"Assigning the Marker to a Trace" on page 196
CALCulate<n>:MARKer<m>:X <Position>
This command moves a marker to a particular coordinate on the x-axis.
If necessary, the command activates the marker.
If the marker has been used as a delta marker, the command turns it into a normal marker.
Parameters:
<Position> Numeric value that defines the marker position on the x-axis.
Range: The range depends on the current x-axis range.
Example: CALC:MARK2:X 1.7MHz
Positions marker 2 to frequency 1.7 MHz.
Manual operation: See
CALCulate<n>:DELTamarker<m>:AOFF
This command turns all delta markers off.
(<m> is irrelevant)
Example:
Usage:
CALC:DELT:AOFF
Turns all delta markers off.
Event
CALCulate<n>:DELTamarker<m>[:STATe] <State>
This command turns delta markers on and off.
If necessary, the command activates the delta marker first.
No suffix at DELTamarker turns on delta marker 1.
Parameters:
<State> ON | OFF
*RST: OFF
Example: CALC:DELT2 ON
Turns on delta marker 2.
Manual operation: See
See
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CALCulate<n>:DELTamarker<m>:TRACe <Trace>
This command selects the trace a delta marker is positioned on.
Note that the corresponding trace must have a trace mode other than "Blank".
If necessary, the command activates the marker first.
Parameters:
<Trace>
Example:
Trace number the marker is assigned to.
CALC:DELT2:TRAC 2
Positions delta marker 2 on trace 2.
CALCulate<n>:DELTamarker<m>:X <Position>
This command moves a delta marker to a particular coordinate on the x-axis.
If necessary, the command activates the delta marker and positions a reference marker to the peak power.
Example: CALC:DELT:X?
Outputs the absolute x-value of delta marker 1.
Manual operation: See
CALCulate<n>:DELTamarker<m>:Y?
This command queries the relative position of a delta marker on the y-axis.
If necessary, the command activates the delta marker first.
To get a valid result, you have to perform a complete measurement with synchronization to the end of the measurement before reading out the result. This is only possible for single measurement mode.
See also
INITiate<n>:CONTinuous on page 333.
The unit depends on the application of the command.
Return values:
<Position>
Example:
Usage:
Position of the delta marker in relation to the reference marker or the fixed reference.
INIT:CONT OFF
Switches to single sweep mode.
INIT;*WAI
Starts a sweep and waits for its end.
CALC:DELT2 ON
Switches on delta marker 2.
CALC:DELT2:Y?
Outputs measurement value of delta marker 2.
Query only
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11.7.2.2
Marker Search and Positioning Settings
Several functions are available to set the marker to a specific position very quickly and easily. In order to determine the required marker position, searches may be performed.
The search results can be influenced by special settings.
Useful commands for positioning markers described elsewhere:
●
CALCulate<n>:MARKer<m>:TRACe on page 341
●
CALCulate<n>:DELTamarker<m>:TRACe on page 343
Remote commands exclusive to positioning markers:
CALCulate<n>:DELTamarker<m>:MAXimum:APEak
This command positions the active marker or deltamarker on the largest absolute peak value (maximum or minimum) of the selected trace.
Usage: Event
CALCulate<n>:DELTamarker<m>:MAXimum:LEFT
This command moves a delta marker to the next higher value.
The search includes only measurement values to the left of the current marker position.
Usage: Event
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CALCulate<n>:DELTamarker<m>:MAXimum:NEXT
This command moves a marker to the next higher value.
Usage: Event
Manual operation: See
"Search Next Peak" on page 198
CALCulate<n>:DELTamarker<m>:MAXimum[:PEAK]
This command moves a delta marker to the highest level.
If the marker is not yet active, the command first activates the marker.
Usage: Event
Manual operation: See
CALCulate<n>:DELTamarker<m>:MAXimum:RIGHt
This command moves a delta marker to the next higher value.
The search includes only measurement values to the right of the current marker position.
Usage: Event
CALCulate<n>:DELTamarker<m>:MINimum:LEFT
This command moves a delta marker to the next higher minimum value.
The search includes only measurement values to the right of the current marker position.
Usage: Event
CALCulate<n>:DELTamarker<m>:MINimum:NEXT
This command moves a marker to the next higher minimum value.
Usage: Event
Manual operation: See
"Search Next Minimum" on page 198
CALCulate<n>:DELTamarker<m>:MINimum[:PEAK]
This command moves a delta marker to the minimum level.
If the marker is not yet active, the command first activates the marker.
Usage: Event
Manual operation: See
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CALCulate<n>:DELTamarker<m>:MINimum:RIGHt
This command moves a delta marker to the next higher minimum value.
The search includes only measurement values to the right of the current marker position.
Usage: Event
CALCulate<n>:MARKer<m>:MAXimum:APEak sets the marker to the largest absolute peak value (maximum or minimum) of the selected trace.
Usage: Event
Manual operation: See
CALCulate<n>:MARKer<m>:MAXimum:LEFT
This command moves a marker to the next lower peak.
The search includes only measurement values to the left of the current marker position.
Usage: Event
CALCulate<n>:MARKer<m>:MAXimum:NEXT
This command moves a marker to the next lower peak.
Usage: Event
Manual operation: See
"Search Next Peak" on page 198
CALCulate<n>:MARKer<m>:MAXimum:RIGHt
This command moves a marker to the next lower peak.
The search includes only measurement values to the right of the current marker position.
Usage: Event
CALCulate<n>:MARKer<m>:MAXimum[:PEAK]
This command moves a marker to the highest level.
If the marker is not yet active, the command first activates the marker.
Usage: Event
Manual operation: See
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CALCulate<n>:MARKer<m>:MINimum:LEFT
This command moves a marker to the next minimum value.
The search includes only measurement values to the right of the current marker position.
Usage: Event
CALCulate<n>:MARKer<m>:MINimum:NEXT
This command moves a marker to the next minimum value.
Usage: Event
Manual operation: See
"Search Next Minimum" on page 198
CALCulate<n>:MARKer<m>:MINimum:RIGHt
This command moves a marker to the next minimum value.
The search includes only measurement values to the right of the current marker position.
Usage: Event
CALCulate<n>:MARKer<m>:MINimum[:PEAK]
This command moves a marker to the minimum level.
If the marker is not yet active, the command first activates the marker.
Usage: Event
Manual operation: See
CALCulate<n>:MARKer<m>:SEARch <MarkRealImag>
This command specifies whether the marker search works on the real or the imag trace (for all markers).
Setting parameters:
<MarkRealImag> REAL | IMAG
*RST: REAL
Manual operation: See
"Real / Imag Plot" on page 197
CALCulate<n>:MARKer<m>:X:SLIMits:LEFT <SearchLimit>
This command defines the left limit of the marker search range for all markers in all windows (<m>, <n> are irrelevant).
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If you perform a measurement in the time domain, this command limits the range of the trace to be analyzed.
Parameters:
<SearchLimit> The value range depends on the frequency range or measurement time.
The unit is Hz for frequency domain measurements and s for time domain measurements.
*RST: left diagram border
<Limit>
Example:
Range:
*RST:
-1e9 to 1e9
0.0
CALC:MARK:X:SLIM ON
Switches the search limit function on.
CALC:MARK:X:SLIM:LEFT 10MHz
Sets the left limit of the search range to 10 MHz.
Manual operation: See
"Search Limits (Left / Right)" on page 197
CALCulate<n>:MARKer<m>:X:SLIMits:RIGHT <SearchLimit>
This command defines the right limit of the marker search range for all markers in all windows (<m>, <n> are irrelevant).
If you perform a measurement in the time domain, this command limits the range of the trace to be analyzed.
Parameters:
<Limit> The value range depends on the frequency range or measurement time.
The unit is Hz for frequency domain measurements and s for time domain measurements.
*RST: right diagram border
<Limit>
Example:
Range:
*RST:
-1e9 to 1e9
800.0
CALC:MARK:X:SLIM ON
Switches the search limit function on.
CALC:MARK:X:SLIM:RIGH 20MHz
Sets the right limit of the search range to 20 MHz.
Manual operation: See
"Search Limits (Left / Right)" on page 197
CALCulate<n>:MARKer<m>:X:SLIMits[:STATe] <State>
This command turns marker search limits on and off for all markers in all windows
(<m>, <n> are irrelevant).
If you perform a measurement in the time domain, this command limits the range of the trace to be analyzed.
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Parameters:
<State>
Example:
ON | OFF
*RST: OFF
CALC:MARK:X:SLIM ON
Switches on search limitation.
Manual operation: See
"Search Limits (Left / Right)" on page 197
11.7.3 Configuring Modulation Accuracy Limit Lines
The results of a modulation accuracy measurement can be checked for violation of defined limits automatically.
Manual configuration of limit lines is described in chapter 6.4, "Modulation Accuracy
11.7.3.1
General Commands
The following commands determine the general behaviour of the limit line check.
CALCulate<n>:LIMit:MACCuracy:DEFault
Restores the default limits and deactivates all checks in all windows.
Usage: Event
Manual operation: See
CALCulate<n>:LIMit:MACCuracy:STATe <LimitState>
Limits checks for all evaluations based on modulation accuracy (e.g. Result Summary) are enabled or disabled.
Setting parameters:
<LimitState> ON | OFF | 1 | 0
*RST: 0
Example: See
chapter 11.13.2, "Measurement Example 2: GSM EDGE
Burst Measurement Based on a Digital Standard" , on page 405.
Manual operation: See
"Checking Modulation Accuracy Limits" on page 200
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11.7.3.2
Defining Limits
The following commands are required to define limits for specific results.
CALCulate<n>:LIMit:MACCuracy:CFERror:CURRent:STATe <LimitState>
CALCulate<n>:LIMit:MACCuracy:CFERror:MEAN:STATe <LimitState>
CALCulate<n>:LIMit:MACCuracy:CFERror:PEAK:STATe <LimitState>
CALCulate<n>:LIMit:MACCuracy:EVM:PCURrent:STATe <LimitState>
CALCulate<n>:LIMit:MACCuracy:EVM:PMEan:STATe <LimitState>
CALCulate<n>:LIMit:MACCuracy:EVM:PPEak:STATe <LimitState>
CALCulate<n>:LIMit:MACCuracy:EVM:RCURrent:STATe <LimitState>
CALCulate<n>:LIMit:MACCuracy:EVM:RMEan:STATe <LimitState>
CALCulate<n>:LIMit:MACCuracy:EVM:RPEak:STATe <LimitState>
CALCulate<n>:LIMit:MACCuracy:FDERror:CURRent:STATe <LimitState>
CALCulate<n>:LIMit:MACCuracy:FDERror:MEAN:STATe <LimitState>
CALCulate<n>:LIMit:MACCuracy:FDERror:PEAK:STATe <LimitState>
CALCulate<n>:LIMit:MACCuracy:FERRor:PCURrent:STATe <LimitState>
CALCulate<n>:LIMit:MACCuracy:FERRor:PMEan:STATe <LimitState>
CALCulate<n>:LIMit:MACCuracy:FERRor:PPEak:STATe <LimitState>
CALCulate<n>:LIMit:MACCuracy:FERRor:RCURrent:STATe <LimitState>
CALCulate<n>:LIMit:MACCuracy:FERRor:RMEan:STATe <LimitState>
CALCulate<n>:LIMit:MACCuracy:FERRor:RPEak:STATe <LimitState>
CALCulate<n>:LIMit:MACCuracy:MERRor:PCURrent:STATe <LimitState>
CALCulate<n>:LIMit:MACCuracy:MERRor:PMEan:STATe <LimitState>
CALCulate<n>:LIMit:MACCuracy:MERRor:PPEak:STATe <LimitState>
CALCulate<n>:LIMit:MACCuracy:MERRor:RCURrent:STATe <LimitState>
CALCulate<n>:LIMit:MACCuracy:MERRor:RMEan:STATe <LimitState>
CALCulate<n>:LIMit:MACCuracy:MERRor:RPEak:STATe <LimitState>
CALCulate<n>:LIMit:MACCuracy:OOFFset:CURRent:STATe <LimitState>
CALCulate<n>:LIMit:MACCuracy:OOFFset:MEAN:STATe <LimitState>
CALCulate<n>:LIMit:MACCuracy:OOFFset:PEAK:STATe <LimitState>
CALCulate<n>:LIMit:MACCuracy:PERRor:PCURrent:STATe <LimitState>
CALCulate<n>:LIMit:MACCuracy:PERRor:PMEan:STATe <LimitState>
CALCulate<n>:LIMit:MACCuracy:PERRor:PPEak:STATe <LimitState>
CALCulate<n>:LIMit:MACCuracy:PERRor:RCURrent:STATe <LimitState>
CALCulate<n>:LIMit:MACCuracy:PERRor:RMEan:STATe <LimitState>
CALCulate<n>:LIMit:MACCuracy:PERRor:RPEak:STATe <LimitState>
CALCulate<n>:LIMit:MACCuracy:RHO:CURRent:STATe <LimitState>
CALCulate<n>:LIMit:MACCuracy:RHO:MEAN:STATe <LimitState>
CALCulate<n>:LIMit:MACCuracy:RHO:PEAK:STATe <LimitState>
CALCulate<n>:LIMit:MACCuracy:<ResultType>:<LimitType>:STATe <LimitState>
This command switches the limit check for the selected result type and limit type on or off.
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Suffix:
<ResultType>
<LimitType>
.
CFERror = Carrier Frequency Error
EVM = Error Vector Magnitude
FERRor = Frequency error (FSK only)
FDERror = Frequency deviation error (FSK only)
MERRor = Magnitude Error
OOFFset = I/Q Offset
PERRor = Phase Error
RHO = Rho
For CFERor, OOFFset, RHO:
CURRent
MEAN
PEAK
For EVM, FERRor, MERRor, PERRor:
PCURRent = Peak current value
PMEan = Peak mean value
PPEak = Peak peak value
RCURRent = RMS current value
RMEan = RMS mean value
RPEak = RMS peak value
Setting parameters:
<LimitState> ON | OFF
Activates a limit check for the selected result and limit type.
*RST: OFF
Example: CALC2:FEED 'XTIM:DDEM:MACC' switch on result summary in screen 2
CALC2:LIM:MACC:CFER:CURR:VAL 100 Hz define a limit of [-100;100]
CALC2:LIM:MACC:CFER:CURR:STAT ON switch limit check ON
Manual operation: See
CALCulate<n>:LIMit:MACCuracy:CFERror:CURRent:VALue <LimitValue>
CALCulate<n>:LIMit:MACCuracy:CFERror:MEAN:VALue <LimitValue>
CALCulate<n>:LIMit:MACCuracy:CFERror:PEAK:VALue <LimitValue>
This command defines the limit for the current, peak or mean center frequency error limit. Note that the limits for the current and the peak value are always kept identical.
Setting parameters:
<LimitValue> numeric value the value x (x>0) defines the interval [-x; x]
Range:
*RST:
0.0 to 1000000
1000.0 (mean: 750.0)
Default unit: Hz
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CALCulate<n>:LIMit:MACCuracy:EVM:PCURrent:VALue <LimitValue>
CALCulate<n>:LIMit:MACCuracy:EVM:PMEan:VALue <LimitValue>
CALCulate<n>:LIMit:MACCuracy:EVM:PPEak:VALue <LimitValue>
CALCulate<n>:LIMit:MACCuracy:EVM:RCURrent:VALue <LimitValue>
CALCulate<n>:LIMit:MACCuracy:EVM:RMEan:VALue <LimitValue>
CALCulate<n>:LIMit:MACCuracy:EVM:RPEak:VALue <LimitValue>
This command defines the value for the current, peak or mean EVM (peak or RMS) limit. Note that the limits for the current and the peak value are always kept identical.
Setting parameters:
<LimitValue> numeric value
Range:
*RST:
0.0 to 100
1.5
Default unit: %
CALCulate<n>:LIMit:MACCuracy:FDERror:CURRent:VALue <LimitValue>
CALCulate<n>:LIMit:MACCuracy:FDERror:MEAN:VALue <LimitValue>
CALCulate<n>:LIMit:MACCuracy:FDERror:PEAK:VALue <LimitValue>
This command defines the lower limit for the current, peak or mean center frequency deviation error. Note that the limits for the current and the peak value are always kept identical.
This command is available for FSK modulation only.
Setting parameters:
<LimitValue> numeric value
Range:
*RST:
0.0 to 1000000
1 kHz
Default unit: Hz
CALCulate<n>:LIMit:MACCuracy:FERRor:PCURrent:VALue <LimitValue>
CALCulate<n>:LIMit:MACCuracy:FERRor:PMEan:VALue <LimitValue>
CALCulate<n>:LIMit:MACCuracy:FERRor:PPEak:VALue <LimitValue>
CALCulate<n>:LIMit:MACCuracy:FERRor:RCURrent:VALue <LimitValue>
CALCulate<n>:LIMit:MACCuracy:FERRor:RMEan:VALue <LimitValue>
CALCulate<n>:LIMit:MACCuracy:FERRor:RPEak:VALue <LimitValue>
This command defines the value for the current, peak or mean frequency error (peak or RMS) limit. Note that the limits for the current and the peak value are always kept identical.
This command is available for FSK modulation only.
Setting parameters:
<LimitValue> numeric value the value x (x>0) defines the interval [-x; x]
Range:
*RST:
0.0 to 100
1.5 (mean: 1.0)
Default unit: Hz
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CALCulate<n>:LIMit:MACCuracy:MERRor:PCURrent:VALue <LimitValue>
CALCulate<n>:LIMit:MACCuracy:MERRor:PMEan:VALue <LimitValue>
CALCulate<n>:LIMit:MACCuracy:MERRor:PPEak:VALue <LimitValue>
CALCulate<n>:LIMit:MACCuracy:MERRor:RCURrent:VALue <LimitValue>
CALCulate<n>:LIMit:MACCuracy:MERRor:RMEan:VALue <LimitValue>
CALCulate<n>:LIMit:MACCuracy:MERRor:RPEak:VALue <LimitValue>
This command defines the value for the current, peak or mean magnitude error (peak or RMS) limit. Note that the limits for the current and the peak value are always kept identical.
Setting parameters:
<LimitValue> numeric value the value x (x>0) defines the interval [-x; x]
Range:
*RST:
0.0 to 100
1.5
Default unit: %
CALCulate<n>:LIMit:MACCuracy:OOFFset:CURRent:VALue <LimitValue>
CALCulate<n>:LIMit:MACCuracy:OOFFset:MEAN:VALue <LimitValue>
CALCulate<n>:LIMit:MACCuracy:OOFFset:PEAK:VALue <LimitValue>
This command defines the upper limit for the current, peak or mean I/Q offset. Note that the limits for the current and the peak value are always kept identical.
Setting parameters:
<LimitValue> numeric value
Range:
*RST:
-200.0 to 0.0
-40.0 (mean: -45.0)
Default unit: DB
CALCulate<n>:LIMit:MACCuracy:PERRor:PCURrent:VALue <LimitValue>
CALCulate<n>:LIMit:MACCuracy:PERRor:PMEan:VALue <LimitValue>
CALCulate<n>:LIMit:MACCuracy:PERRor:PPEak:VALue <LimitValue>
CALCulate<n>:LIMit:MACCuracy:PERRor:RCURrent:VALue <LimitValue>
CALCulate<n>:LIMit:MACCuracy:PERRor:RMEan:VALue <LimitValue>
CALCulate<n>:LIMit:MACCuracy:PERRor:RPEak:VALue <LimitValue>
This command defines the value for the current, peak or mean phase error (peak or
RMS) limit. Note that the limits for the current and the peak value are always kept identical.
Setting parameters:
<LimitValue> numeric value the value x (x>0) defines the interval [-x; x]
Range: 0.0 to 360
*RST: 3.5 (RMS: 1.5)
Default unit: deg
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CALCulate<n>:LIMit:MACCuracy:RHO:CURRent:VALue <LimitValue>
CALCulate<n>:LIMit:MACCuracy:RHO:MEAN:VALue <LimitValue>
CALCulate<n>:LIMit:MACCuracy:RHO:PEAK:VALue <LimitValue>
This command defines the lower limit for the current, peak or mean Rho limit. Note that the limits for the current and the peak value are always kept identical.
Setting parameters:
<LimitValue> numeric value
Range:
*RST:
0.0 to 1.0
0.999 (mean: 0.9995)
Default unit: NONE
11.7.4 Configuring an Analysis Interval and Line (MSRA mode only)
In MSRA operating mode, only the MSRA Master actually captures data; the MSRA applications define an extract of the captured data for analysis, referred to as the
analysis interval. The analysis line is a common time marker for all MSRA applications.
For the VSA application, the commands to define tha analysis interval are the same as
these commands.
Useful commands related to MSRA mode described elsewhere:
●
INITiate<n>:REFResh on page 335
●
INITiate<n>:SEQuencer:REFResh[:ALL] on page 335
Remote commands exclusive to MSRA applications
The following commands are only available for MSRA application channels:
CALCulate<n>:MSRA:WINDow<n>:IVAL?
........................................................................355
CALCulate<n>:MSRA:ALINe:SHOW
This command defines whether or not the analysis line is displayed in all time-based windows in all MSRA applications and the MSRA Master.
(<n> is irrelevant.)
Note: even if the analysis line display is off, the indication whether or not the currently defined line position lies within the analysis interval of the active application remains in the window title bars.
Parameters:
<State> ON | OFF
*RST: ON
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CALCulate<n>:MSRA:ALINe[:VALue] <Position>
This command defines the position of the analysis line for all time-based windows in all
MSRA applications and the MSRA Master.
(<n> is irrelevant.)
Parameters:
<Position> Position of the analysis line in seconds. The position must lie within the measurement time of the MSRA measurement.
Default unit: s
CALCulate<n>:MSRA:WINDow<n>:IVAL?
This command queries the analysis interval for the window specified by the WINDow suffix <n> (the CALC suffix is irrelevant). This command is only available in application measurement channels, not the MSRA View or MSRA Master.
Return values:
<IntStart> Start value of the analysis interval in seconds
Default unit: s
<IntStop> Stop value of the analysis interval in seconds
Usage: Query only
[SENSe:]MSRA:CAPTure:OFFSet <Offset>
This setting is only available for applications in MSRA mode, not for the MSRA Master.
It has a similar effect as the trigger offset in other measurements.
Parameters:
<Offset> This parameter defines the time offset between the capture buffer start and the start of the extracted application data. The offset must be a positive value, as the application can only analyze data that is contained in the capture buffer.
Range:
*RST:
0 to <Record length>
0
Manual operation: See
11.7.5 Zooming into the Display
11.7.5.1
Using the Single Zoom
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DISPlay[:WINDow<n>]:ZOOM:AREA <x1>,<y1>,<x2>,<y2>
This command defines the zoom area.
To define a zoom area, you first have to turn the zoom on.
1 = origin of coordinate system (x1 = 0, y1 = 0)
2 = end point of system (x2 = 100, y2= 100)
3 = zoom area (e.g. x1 = 60, y1 = 30, x2 = 80, y2 = 75)
Parameters:
<x1>,<y1>,
<x2>,<y2>
Diagram coordinates in % of the complete diagram that define the zoom area.
The lower left corner is the origin of coordinate system. The upper right corner is the end point of the system.
Range: 0 to 100
Default unit: PCT
Manual operation: See
DISPlay[:WINDow<n>]:ZOOM:STATe <State>
This command turns the zoom on and off.
Parameters:
<State>
Example:
ON | OFF
*RST: OFF
DISP:ZOOM ON
Activates the zoom mode.
Manual operation: See
See
"Restore Original Display" on page 205
See
" Deactivating Zoom (Selection mode)" on page 205
11.7.5.2
Using the Multiple Zoom
DISPlay[:WINDow<n>]:ZOOM:MULTiple<zoom>:AREA <x1>,<y1>,<x2>,<y2>
This command defines the zoom area for a multiple zoom.
To define a zoom area, you first have to turn the zoom on.
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1 = origin of coordinate system (x1 = 0, y1 = 0)
2 = end point of system (x2 = 100, y2= 100)
3 = zoom area (e.g. x1 = 60, y1 = 30, x2 = 80, y2 = 75)
Suffix:
<zoom>
.
1...4
Selects the zoom window.
Parameters:
<x1>,<y1>,
<x2>,<y2>
Diagram coordinates in % of the complete diagram that define the zoom area.
The lower left corner is the origin of coordinate system. The upper right corner is the end point of the system.
Range: 0 to 100
Default unit: PCT
Manual operation: See
DISPlay[:WINDow<n>]:ZOOM:MULTiple<zoom>:STATe <State>
This command turns the mutliple zoom on and off.
Suffix:
<zoom>
.
1...4
Selects the zoom window.
If you turn off one of the zoom windows, all subsequent zoom windows move up one position.
Parameters:
<State> ON | OFF
*RST: OFF
Manual operation: See
See
"Restore Original Display" on page 205
See
" Deactivating Zoom (Selection mode)" on page 205
11.8 Configuring the Result Display
The following commands are required to configure the result display in a remote envi-
ronment. The tasks for manual operation are described in chapter 6.5, "Display and
Window Configuration" , on page 201.
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11.8.1 General Window Commands
The following commands are required to configure general window layout, independent of the application.
Note that the suffix <n> always refers to the window in the currently selected measure-
ment channel (see
INSTrument[:SELect] on page 272).
DISPlay:FORMat <Format>
This command determines which tab is displayed.
Parameters:
<Format>
Example:
SPLit
Displays the MultiView tab with an overview of all active channels
SINGle
Displays the measurement channel that was previously focused.
*RST: SING
DISP:FORM SPL
DISPlay[:WINDow<n>]:SIZE <Size>
This command maximizes the size of the selected result display window temporarily.
To change the size of several windows on the screen permanently, use the LAY:SPL
command (see LAYout:SPLitter on page 361).
Parameters:
<Size> LARGe
Maximizes the selected window to full screen.
Other windows are still active in the background.
SMALl
Reduces the size of the selected window to its original size.
If more than one measurement window was displayed originally, these are visible again.
*RST: SMALl
Example: DISP:WIND2:LARG
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11.8.2 Working with Windows in the Display
The following commands are required to change the evaluation type and rearrange the screen layout for a measurement channel as you do using the SmartGrid in manual operation. Since the available evaluation types depend on the selected application, some parameters for the following commands also depend on the selected measurement channel.
Note that the suffix <n> always refers to the window in the currently selected measure-
ment channel (see
INSTrument[:SELect] on page 272).
.................................................................................................359
...........................................................................................360
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.............................................................................................363
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LAYout:ADD[:WINDow]? <WindowName>,<Direction>,<WindowType>
This command adds a window to the display in the active measurement channel.
This command is always used as a query so that you immediately obtain the name of the new window as a result.
To replace an existing window, use the
LAYout:REPLace[:WINDow] command.
Parameters:
<WindowName>
<Direction>
<WindowType>
String containing the name of the existing window the new window is inserted next to.
By default, the name of a window is the same as its index. To determine the name and index of all active windows, use the
LEFT | RIGHt | ABOVe | BELow
Direction the new window is added relative to the existing window.
text value
Type of result display (evaluation method) you want to add.
See the table below for available parameter values.
Return values:
<NewWindowName> When adding a new window, the command returns its name (by default the same as its number) as a result.
Example: LAY:ADD:WIND? '1',RIGH,SYMB
Adds a Symbol Table display to the right of window 1.
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Usage: Query only
Manual operation: See
See
"Measurement & Reference Signal" on page 15
See
See
See
"Modulation Errors" on page 16
See
"Modulation Accuracy" on page 17
See
See
For a detailed example see chapter 11.13.1, "Measurement Example 1: User-defined
Measurement of Continuous QPSK Signal" , on page 404.
Table 11-2: <WindowType> parameter values for VSA application
Parameter value Data source (+default result display)
Capture buffer (Magnitude absolute)
Meas & Ref (Magnitude relative)
CBUFfer
MEAS
REF
EQUalizer
EVECtor
MACCuracy
MERRor
SYMB
Equalizer
Error vector (EVM)
Modulation Accuracy (Result Summary)
Modulation Errors (Magnitude error)
Symbols (Hexadecimal)
LAYout:CATalog[:WINDow]?
This command queries the name and index of all active windows in the active measurement channel from top left to bottom right. The result is a comma-separated list of values for each window, with the syntax:
<WindowName_1>,<WindowIndex_1>..<WindowName_n>,<WindowIndex_n>
Return values:
<WindowName> string
Name of the window.
In the default state, the name of the window is its index.
<WindowIndex>
Example:
Usage: numeric value
Index of the window.
LAY:CAT?
Result:
'2',2,'1',1
Two windows are displayed, named '2' (at the top or left), and '1'
(at the bottom or right).
Query only
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LAYout:IDENtify[:WINDow]? <WindowName>
This command queries the index of a particular display window in the active measurement channel.
Note: to query the name of a particular window, use the LAYout:WINDow<n>:
query.
Query parameters:
<WindowName> String containing the name of a window.
Return values:
<WindowIndex>
Usage:
Index number of the window.
Query only
LAYout:REMove[:WINDow] <WindowName>
This command removes a window from the display in the active measurement channel.
Parameters:
<WindowName>
Usage:
String containing the name of the window.
In the default state, the name of the window is its index.
Event
LAYout:REPLace[:WINDow] <WindowName>,<WindowType>
This command replaces the window type (for example from "Diagram" to "Result Summary") of an already existing window in the active measurement channel while keeping its position, index and window name.
To add a new window, use the
Parameters:
<WindowName>
<WindowType>
Example:
String containing the name of the existing window.
By default, the name of a window is the same as its index. To determine the name and index of all active windows in the active
measurement channel, use the LAYout:CATalog[:WINDow]?
query.
Type of result display you want to use in the existing window.
See
on page 359 for a list of availa-
ble window types.
LAY:REPL:WIND '1',MTAB
Replaces the result display in window 1 with a marker table.
LAYout:SPLitter <Index1>,<Index2>,<Position>
This command changes the position of a splitter and thus controls the size of the windows on each side of the splitter.
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Compared to the
DISPlay[:WINDow<n>]:SIZE on page 358 command, the
LAYout:SPLitter changes the size of all windows to either side of the splitter permanently, it does not just maximize a single window temporarily.
Note that windows must have a certain minimum size. If the position you define conflicts with the minimum size of any of the affected windows, the command will not work, but does not return an error.
Fig. 11-1: SmartGrid coordinates for remote control of the splitters
Parameters:
<Index1>
<Index2>
<Position>
Example:
The index of one window the splitter controls.
The index of a window on the other side of the splitter.
New vertical or horizontal position of the splitter as a fraction of the screen area (without channel and status bar and softkey menu).
The point of origin (x = 0, y = 0) is in the lower left corner of the screen. The end point (x = 100, y = 100) is in the upper right corner of the screen. (See
.)
The direction in which the splitter is moved depends on the screen layout. If the windows are positioned horizontally, the splitter also moves horizontally. If the windows are positioned vertically, the splitter also moves vertically.
Range: 0 to 100
LAY:SPL 1,3,50
Moves the splitter between window 1 ('Frequency Sweep') and 3
('Marker Table') to the center (50%) of the screen, i.e. in the figure above, to the left.
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Remote Commands for VSA
Configuring the Result Display
LAY:SPL 1,4,70
Moves the splitter between window 1 ('Frequency Sweep') and 3
('Marker Peak List') towards the top (70%) of the screen.
The following commands have the exact same effect, as any combination of windows above and below the splitter moves the splitter vertically.
LAY:SPL 3,2,70
LAY:SPL 4,1,70
LAY:SPL 2,1,70
LAYout:WINDow<n>:ADD? <Direction>,<WindowType>
This command adds a measurement window to the display. Note that with this command, the suffix <n> determines the existing window next to which the new window is added, as opposed to
, for which the existing window is
defined by a parameter.
To replace an existing window, use the
LAYout:WINDow<n>:REPLace command.
This command is always used as a query so that you immediately obtain the name of the new window as a result.
Parameters:
<Direction>
<WindowType>
LEFT | RIGHt | ABOVe | BELow
Type of measurement window you want to add.
See
on page 359 for a list of availa-
ble window types.
Return values:
<NewWindowName> When adding a new window, the command returns its name (by default the same as its number) as a result.
Example: LAY:WIND1:ADD? LEFT,MTAB
Result:
'2'
Adds a new window named '2' with a marker table to the left of window 1.
Usage: Query only
LAYout:WINDow<n>:IDENtify?
This command queries the name of a particular display window (indicated by the <n> suffix) in the active measurement channel.
Note: to query the index of a particular window, use the LAYout:IDENtify[:
command.
Return values:
<WindowName> String containing the name of a window.
In the default state, the name of the window is its index.
Usage: Query only
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LAYout:WINDow<n>:REMove
This command removes the window specified by the suffix <n> from the display in the active measurement channel.
The result of this command is identical to the LAYout:REMove[:WINDow]
command.
Usage: Event
LAYout:WINDow<n>:REPLace <WindowType>
This command changes the window type of an existing window (specified by the suffix
<n>) in the active measurement channel.
The result of this command is identical to the LAYout:REPLace[:WINDow]
command.
To add a new window, use the
Parameters:
<WindowType> Type of measurement window you want to replace another one with.
See
on page 359 for a list of availa-
ble window types.
LAYout:WINDow<n>:TYPe?
Queries the window type of the window specified by the index <n>. For a list of possible window types see
Example: LAY:WIND2:TYPE?
Response:
MACC
Modulation accuracy
Usage: Query only
11.8.3 VSA Window Configuration
For each window you can select a different evaluation method (result type), based on the data source selected in the "Display Configuration". Further window settings are available for some result types.
Useful commands for configuring the window described elsewhere:
●
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Remote commands exclusive to configuring VSA windows:
CALCulate<n>:DDEM:SPECtrum[:STATe] <AddEvaluation>
This command switches the result type transformation to spectrum mode. Spectral evaluation is available for the following result types:
● MAGNitude
● PHASe/UPHase
● FREQuency
● Real/Imag (RIMAG)
The result types are defined using the CALC:FORM command (see
Setting parameters:
<AddEvaluation> ON | OFF | 1 | 0
*RST: 0
Example: CALC:FEED 'XTIM:DDEM:MEAS'
Selects the meas signal.
CALC:FORM PHAS
Selects the phase measurement.
CALC:DDEM:SPEC:STAT ON
Selects the spectral display of the phase.
Manual operation: See
"Result Type Transformation" on page 202
CALCulate<n>:FEED <Feed>
Selects the signal source (and for the equalizer also the result type) for evaluation.
Note that this command is maintained for compatibility reasons only. Use the LAYout commands for new remote control programs (see
chapter 11.8.2, "Working with Windows in the Display" , on page 359).
Only for the "Equalizer Impulse Response" and "Equalizer Frequency Response" this command is required.
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Setting parameters:
<Feed> string
'XTIM:DDEM:MEAS'
Measured signal
'XTIM:DDEM:REF'
Reference signal
'XTIM:DDEM:ERR:VECT'
Error vector
'XTIM:DDEM:ERR:MPH'
Modulation errors
'XTIM:DDEM:MACC'
Modulation accuracy
'XTIM:DDEM:SYMB'
Symbol table
'TCAP'
Capture Buffer
'XTIM:DDEM:IMP'
Equalizer Impulse Response
'XFR:DDEM:RAT'
Equalizer Frequency Response
'XFR:DDEM:IRAT'
Equalizer Channel Frequency Response Group Delay
CALCulate<n>:FORMat <Format>
This command defines the result type of the traces. Which parameters are available depends on the setting for the data source (see
).
Whether the result type shows absolute or relative values is defined using the
DISP:WIND:TRAC:Y:MODE command (see
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Setting parameters:
<Format> MAGNitude | PHASe | UPHase | RIMag | FREQuency | COMP |
CONS | IEYE | QEYE | FEYE | CONF | COVF | RCONstellation |
RSUMmary | BERate | GDELay | MOVerview | NONE
MAGNitude
Magnitude Absolute
MOVerview
Magnitude Overview Absolute (entire capture buffer)
PHASe
Phase Wrap
UPHase
Phase Unwrap
RIMag
Real/Imag (I/Q)
FREQuency
Frequency Absolute
COMP
Vector I/Q
CONS
Constellation I/Q
IEYE
Eye Diagram Real (I)
QEYE
Eye Diagram Imag (Q)
FEYE
Eye Diagram Frequency
CONF
Constellation Frequency
COVF
Vector Frequency
RCONstellation
Constellation I/Q (Rotated)
RSUMmary
Result summary
BERate
Bit error rate
GDELay
Frequency Response Group Delay
Example: See
chapter 11.13.1, "Measurement Example 1: User-defined
Measurement of Continuous QPSK Signal" , on page 404.
Manual operation: See
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CALCulate<n>:STATistics:CCDF[:STATe] <AddEvaluation>
This command switches the measurement of the statistical distribution of magnitude, phase or frequency values on or off.
Setting parameters:
<AddEvaluation> ON | OFF | 1 | 0
*RST: 0
Manual operation: See
"Result Type Transformation" on page 202
CALCulate<n>:STATistics:MODE <StatisticMode>
This command defines whether only the symbol points or all points are considered for the statistical calculations.
Setting parameters:
<StatisticMode> SONLy | INFinite
SONLy
Symbol points only are used
INFinite
All points are used
*RST: SONLy
Manual operation: See
DISPlay[:WINDow<n>]:ITEM[:LINE][:VALue] <SingleValue>
DISPlay[:WINDow<n>]:ITEM[:LINE][:VALue]? <SingleValue>
This commands switches between the whole Result Summary and the diagram showing only a single value, e.g. the EVM RMS value as a bargraph. The same parameters
are available as those for which modulation accuracy limits can be defined (see "Limit
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Parameters:
<SingleValue> ALL | EVMR | EVMP | PERM | PEP | MERM | MEP | CFER |
RHO | IQOF | FERM | FEP | FDER
ALL
Complete Result Summary
EVMR
RMS EVM
EVMP
Peak EVM
PERM
RMS Phase error
PEP
Peak phase error
MERM
RMS Magnitude error
MEP
Peak magnitude error
CFER
Carrier frequency error
RHO
RHO
IQOF
I/Q offset
FERM
RMS frequency error
FEP
Peak frequency error
FDER
FSK deviation error
*RST: ALL
Manual operation: See
"Result Summary - Individual Results" on page 50
DISPlay[:WINDow<n>]:PRATe:AUTO <DisplayPPSMode>
Defines the number of display points that are displayed per symbol automatically, i.e.
according to
[SENSe:]DDEMod:PRATe on page 301. To define a different number of
points per symbol for display, use the MANual parameter and the
command.
Setting parameters:
<DisplayPPSMode> AUTO | MANual
*RST: AUTO
Manual operation: See
"Display Points/Sym" on page 203
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DISPlay[:WINDow<n>]:PRATe[:VALue] <DisplayPPS>
This command determines the number of points to be displayed per symbol if manual
mode is selected (see DISPlay[:WINDow<n>]:PRATe:AUTO on page 369).
This command is not available for result displays based on the capture buffer; in this
case, the displayed points per symbol are defined by the sample rate ( [SENSe:
command).
Setting parameters:
<DisplayPPS> 1, 2, 4, 8,16 or 32
1 only the symbol time instants are displayed
2, 4, 8, 16, 32 more points are displayed than symbols
*RST: 4
Manual operation: See
"Display Points/Sym" on page 203
DISPlay[:WINDow<n>]:TRACe:SYMBol
This command enables the display of the decision instants (time when the signals occurred) as dots on the trace.
Manual operation: See
"Highlight Symbols" on page 203
DISPlay[:WINDow<n>]:TRACe<t>:Y[:SCALe]:MODE <Mode>
This command selects the type of scaling of the y-axis (for all traces, <t> is irrelevant).
When the display update during remote control is off, this command has no immediate effect.
Parameters:
<Mode> ABSolute absolute scaling of the y-axis
RELative relative scaling of the y-axis
*RST: ABSolute
Example: DISP:TRAC:Y:MODE REL
11.9 Retrieving Results
The following commands are required to retrieve the calculated VSA parameters.
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All results that are not based on the capture buffer data are calculated for a single result range only (see
chapter 4.6.1, "Result Range" , on page 117). To retrieve the
● Measurement Results for TRACe<n>[:DATA]? TRACE<n> .................................375
11.9.1 Retrieving Trace Data and Marker Values
In order to retrieve the trace and marker results in a remote environment, use the following commands:
CALCulate<n>:DELTamarker<m>:X:ABSolute?
................................................................ 371
CALCulate<n>:DELTamarker<m>:X:RELative?
.................................................................371
.......................................................................................372
DISPlay[:WINDow<n>]:TRACe<t>:X[:SCALe]:STARt?
....................................................... 372
DISPlay[:WINDow<n>]:TRACe<t>:X[:SCALe]:STOP?
........................................................372
[SENSe:]DDEMod:SEARch:MBURst:STARt?
................................................................... 374
CALCulate<n>:DELTamarker<m>:X:ABSolute?
This command queries the absolute x-value of the selected delta marker in the specified window. The command activates the corresponding delta marker, if necessary.
Usage: Query only
CALCulate<n>:DELTamarker<m>:X:RELative?
This command queries the relative position of a delta marker on the x-axis.
If necessary, the command activates the delta marker first.
Return values:
<Position>
Example:
Position of the delta marker in relation to the reference marker.
CALC:DELT3:X:REL?
Outputs the frequency of delta marker 3 relative to marker 1 or relative to the reference position.
Usage: Query only
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CALCulate<n>:MARKer<m>:Y?
This command queries the position of a marker on the y-axis.
If necessary, the command activates the marker first.
To get a valid result, you have to perform a complete measurement with synchronization to the end of the measurement before reading out the result. This is only possible for single measurement mode.
See also
INITiate<n>:CONTinuous on page 333.
Return values:
<Result>
Example:
Usage:
Result at the marker position.
INIT:CONT OFF
Switches to single measurement mode.
CALC:MARK2 ON
Switches marker 2.
INIT;*WAI
Starts a measurement and waits for the end.
CALC:MARK2:Y?
Outputs the measured value of marker 2.
Query only
DISPlay[:WINDow<n>]:TRACe<t>:X[:SCALe]:STARt?
This command queries the first value of the x-axis in the specified window in symbols or time, depending on the unit setting for the x-axis.
Note: using the
CALCulate<n>:TRACe<t>:ADJust:ALIGnment:OFFSet com-
mand, the burst is shifted in the diagram; the x-axis thus no longer begins on the left at
0 symbols but at a selectable value.
Example:
Usage:
See
chapter 11.13.2, "Measurement Example 2: GSM EDGE
Burst Measurement Based on a Digital Standard" , on page 405.
Query only
DISPlay[:WINDow<n>]:TRACe<t>:X[:SCALe]:STOP?
This command queries the last value of the x-axis in the specified window in symbols or time, depending on the unit setting for the x-axis.
Note: If the burst is shifted (using the CALC:TRAC:ALIG commands) the x-axis no longer begins at 0 symbols on the left, but at a user-defined value.
Example: CALC:TRAC:ADJ BURS
Defines the burst as the reference for the screen display
CALC:TRAC:ADJ:ALIG CENT
Position the burst at the center of the screen
DISP:TRAC:X:STOP?
Queries the stop value of the x-axis
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Usage: Query only
FORMat:DEXPort:DSEParator <Separator>
This command selects the decimal separator for data exported in ASCII format.
Parameters:
<Separator> COMMa
Uses a comma as decimal separator, e.g. 4,05.
POINt
Uses a point as decimal separator, e.g. 4.05.
*RST: *RST has no effect on the decimal separator.
Default is POINt.
Example: FORM:DEXP:DSEP POIN
Sets the decimal point as separator.
Manual operation: See
"Decimal Separator" on page 194
FORMat:DEXPort:HEADer <Header>
This command defines if a file header (including start frequency, sweep time, detector, etc.) is created or not. A small header with the instrument model, the version and the date is always transferred.
Setting parameters:
<Header> ON | OFF | 1 | 0
*RST: 0
Example: See
chapter 11.13.2, "Measurement Example 2: GSM EDGE
Burst Measurement Based on a Digital Standard" , on page 405.
Manual operation: See
FORMat:DEXPort:MODE <Mode>
This command defines which data are transferred, raw I/Q data or trace data.
Setting parameters:
<Mode> RAW | TRACe
*RST: TRACe
Example: See
chapter 11.13.2, "Measurement Example 2: GSM EDGE
Burst Measurement Based on a Digital Standard" , on page 405.
Manual operation: See
"Data Export Mode" on page 193
MMEMory:STORe<n>:TRACe <Trace>, <FileName>
This command exports trace data from the specified window to an ASCII file.
Secure User Mode
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In secure user mode, settings that are to be stored on the instrument are stored to volatile memory, which is restricted to 256 MB. Thus, a "Memory full" error may 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 User Manual.
Parameters:
<Trace>
<FileName>
Example:
Number of the trace to be stored
String containing the path and name of the target file.
MMEM:STOR1:TRAC 3,'C:\TEST.ASC'
Stores trace 3 from window 1 in the file TEST.ASC.
Usage: SCPI confirmed
Manual operation: See
"Trace ASCII Export" on page 194
See
"Export Trace to ASCII File" on page 207
[SENSe:]DDEMod:SEARch:MBURst:STARt?
This command queries the start of the current result range within the capture buffer.
Return values:
<StartValue>
Example:
Symbol or time at which x-axis starts
INIT:CONT OFF
//switch to single sweep mode
INIT;*WAI
//perform single sweep
SENS:DDEM:SEAR:MBUR:CALC 1
//switch to first result range
SENS:DDEM:SEAR:MBUR:START?
//query start of current (=first) result range
// in the capture buffer
SENS:DDEM:SEAR:MBUR:CALC 2
//switch to second result range
SENS:DDEM:SEAR:MBUR:START?
//query start of current (=second) result range
// in the capture buffer
Usage: Query only
TRACe<n>[:DATA] <Trace>
This command queries the trace data.
Which data is returned depends on the result display in the window specified by the suffix <n>.
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For details see
chapter 11.9.2, "Measurement Results for TRACe<n>[:DATA]?
Setting parameters:
<Trace> TRACe1 | TRACe2 | TRACe3 | TRACe4 | TRACe5 | TRACe6 |
TRACe1R | TRACe1I | TRACe2R | TRACe2I | TRACe3R |
TRACe3I
TRACe1/2/3/4/5/6
The complete data from the corresponding trace.
TRACe1R/TRACe2R/TRACe3R
The real data from the corresponding trace. The parameters are available for the Real/Imaginary result types.
TRACe1I/TRACe2I/TRACe3I
The imaginary data from the corresponding trace. The parameters are available for the Real/Imaginary result types.
Example: See
chapter 11.13.3, "Measurement Example 3: User-Defined
Pattern Search and Limit Check" , on page 409.
11.9.2 Measurement Results for TRACe<n>[:DATA]? TRACE<n>
The evaluation data source selected by the LAY:ADD:WIND command and the result type selected by the
CALCulate<n>:FORMat command also affect the results of the
trace data query (see TRACe<n>[:DATA]? TRACE<n> ).
Details on the returned trace data depending on the evaluation data source and result type are provided here.
11.9.2.1
Capture Buffer Results
For the result displays based on the capture buffer, the command returns the y-axis values of the data that is stored in the capture buffer. The number of returned values depends on the size of the capture buffer and the sample rate. For example, a capture buffer size of 500 symbols in combination with a sample rate of 4 would return 2000 level values.
The scaling of the capture buffer depends on the input source:
● Scaling is relative to the current reference level for RF input.
● Scaling is relative to the full scale level for I/Q input.
The unit is dBm.
Note that the trace results return only the values for the currently displayed capture
buffer range (see also chapter 4.8, "Capture Buffer Display" , on page 122). For the
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Magnitude Overview Absolute result display, this command returns a maximum of
25,000 values (corresponding to the displayed trace points).
You can query the x-value that relates to the first value of the y-axis using DISPlay[:
WINDow<n>]:TRACe<t>:X[:SCALe]:STARt?
11.9.2.2
Cartesian Diagrams
For cartesian diagrams (magnitude, phase, frequency, real/imag, eye diagrams), the command returns the y-values of the trace. The number of returned values is the product of the "Result Length" and the display points per symbol. The unit depends on the specified unit.
(See
chapter 11.5.2.6, "Scaling and Units" , on page 296).
You can query the x-value that relates to the first value of the y-axis using DISPlay[:
WINDow<n>]:TRACe<t>:X[:SCALe]:STARt?
The eye diagram result displays are the same as the real/imag result display; the results for eye diagrams are merely superimposed in the display.
11.9.2.3
Polar Diagrams
For polar diagrams, the command returns a pair of values for each trace point. The first value is the real part, the second value the imaginary part. The number of returned value pairs depends on the result type:
● Vector I/Q: evaluation range length * display points per symbol
● Constellation I/Q: evaluation range length
● Constellation Frequency and Vector Frequency: one value for each trace point on the y-axis
11.9.2.4
Symbols
For the symbol table result diagrams, the command returns one value for each number in the table. The command always returns the values in the decimal format. The number of returned values depends on the modulation scheme you have selected.
11.9.2.5
Result Summary
For the Result Summary, the command returns all values listed in the result table from top to bottom, i.e.:
<EVM_RMS>,<EVM_Peak>,<MER_RMS>,<MER_Peak>,<Phase Error RMS>,<Phase
Error Peak>,<MagError_RMS>,<MagError_Peak>,<Carrier Frequency
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Error>,<Rho>,<I/Q Offset>,<I/Q Imbalance>,<Gain Imbalance>,<Quadratue
Error>,Amplitude Droop>,<Power>,<Symbol Rate Error>
(Note that the "Symbol Rate Error" was appended at the end to provide compatibility to previous versions and instruments.)
For each result type, both the current and statistical values are provided. The order of the results is as follows:
<result1_current>, <result1_mean>, <result1_peak>, <result1_stddev>,
<result1_95%ile>,
<result2_current>, <result2_mean>, (...)
Empty cells in the table return nothing. The number of returned values depends on the modulation scheme you have selected. PSK, MSK and QAM modulation returns 85 values, FSK modulation returns 55 values. The unit of each value depends on the particular result.
For more details on the Result Summary see
chapter 3.2.29, "Result Summary" , on page 47.
11.9.2.6
Equalizer
For Equalizer diagrams, the command returns the y-axis values of the equalizer trace.
The number of returned values depends on the result type:
● For impulse response diagrams:
(filter length * sample rate) +1
● For frequency response, channel and group delay diagrams: 4096 values
You can query the x-value that relates to the first value of the y-axis using DISPlay[:
WINDow<n>]:TRACe<t>:X[:SCALe]:STARt?
11.9.3 Retrieving Parameter Values
For each parameter, the VSA application calculates and shows various statistical values:
● Current value
● Mean value
Calculated as the average of the number of results defined by the Statistic Count .
● Peak value
● Standard deviation
● 95 percentile
Unlike the mean value, the 95%ile is a result of all measurement results since the last start of a single or continous sweep, or of all measurements since the last change of a measurement parameter.
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For details on the individual parameters see chapter 3.3, "Common Parameters in
on page 54 and chapter A.6, "Formulae" , on page 425.
CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:ADRoop?
.................................378
CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:ALL?
....................................... 379
CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:CFERror?
................................ 379
CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:EVM?
......................................380
CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:FDERror?
................................ 380
CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:FSK:CFDRift?
.......................... 381
CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:FSK:DERRor?
CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:FSK:MDEViation?
CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:FSK:RDEViation?
CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:GIMBalance?
........................... 383
CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:IQIMbalance?
.......................... 383
CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:MERRor?
................................ 384
CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:MPOWer?
............................... 385
CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:OOFFset?
............................... 385
CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:PERRor?
.................................385
CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:QERRor?
.................................386
CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:RHO?
......................................387
CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:SNR?
......................................387
CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:SRERror?
................................388
CALCulate<n>:BERate <Format>
Queries the Bit Error Rate results. The available results are described in
"Bit Error Rate (BER)" , on page 20.
Query parameters:
<Format> Specifies a particular BER result to be queried. If no parameter is specified, the current bit error rate is returned.
The parameters for these results are listed in
.
Table 11-3: Parameters for BER result values
Result Current Min Max Acc
Bit Error Rate
Total # of Errors
Total # of Bits
CURRent
TECurrent
TCURrent
MIN
TEMIN
TMIN
MAX
TEMAX
TMAX
TOTal
TETotal
TTOTal
CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:ADRoop? <type>
This command queries the results of the amplitude droop error measurement performed for digital demodulation. The output values are the same as those provided in the Modulation Accuracy table (see
chapter 3.2.29, "Result Summary" , on page 47).
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Query parameters:
<type> <none>
Amplitude droop in dB/symbol (for current sweep)
AVG
Amplitude droop in dB/symbol, evaluating the linear average value over several sweeps
RPE
Peak value for amplitude droop over several sweeps
SDEV
Standard deviation of amplitude droop
PCTL
95 percentile value of amplitude droop
Usage: Query only
CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:ALL?
The command queries all results of the result summary as shown on the screen.
Usage: Query only
CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:CFERror? <type>
This command queries the results of the carrier frequency error measurement performed for digital demodulation.
The output values are the same as those provided in the Modulation Accuracy table.
Query parameters:
<type> <none>
Carrier frequency error for current sweep
AVG
Average carrier frequency error over several sweeps
RPE
Peak carrier frequency error over several sweeps
SDEV
Standard deviation of frequency error
PCTL
95 percentile value of frequency error
Example:
Usage:
See
chapter 11.13.2, "Measurement Example 2: GSM EDGE
Burst Measurement Based on a Digital Standard" , on page 405.
Query only
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CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:EVM? <type>
This command queries the results of the error vector magnitude measurement of digital demodulation. The output values are the same as those provided in the Modulation
Accuracy table .
Query parameters:
<type> <none>
RMS EVM value of display points of current sweep
AVG
Average of RMS EVM values over several sweeps
PAVG
Average of maximum EVM values over several sweeps
PCTL
95% percentile of RMS EVM value over several sweeps
PEAK
Maximum EVM over all symbols of current sweep
PPCT
95% percentile of maximum EVM values over several sweeps
PSD
Standard deviation of maximum EVM values over several sweeps
RPE
Maximum value of RMS EVM over several sweeps
SDEV
Standard deviation of EVM values over several sweeps
TPE
Maximum EVM over all display points over several sweeps
Example:
Usage:
See
chapter 11.13.2, "Measurement Example 2: GSM EDGE
Burst Measurement Based on a Digital Standard" , on page 405.
Query only
CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:FDERror? <type>
This command queries the results of the FSK deviation error of FSK modulated signals.
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Query parameters:
<type>
Usage:
<none>
Deviation error for current sweep.
AVG
Average FSK deviation error.
RPE
Peak FSK deviation error.
SDEV
Standard deviation of FSK deviation error.
PCTL
95 percentile value of FSK deviation error.
Query only
CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:FSK:CFDRift? <type>
This command queries the results of the carrier frequency drift for FSK modulated signals.
Query parameters:
<type>
Usage:
<none>
Carrier frequency drift for current sweep.
AVG
Average FSK carrier frequency drift over several sweeps.
RPE
Peak FSK carrier frequency drift over several sweeps.
SDEV
Standard deviation of FSK carrier frequency drift.
PCTL
95 percentile value of FSK carrier frequency drift.
Query only
CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:FSK:DERRor? <type>
This command queries the results of the frequency error of FSK modulated signals.
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Query parameters:
<type> <none>
RMS frequency error of display points of current sweep
AVG
Average of RMS frequency errors over several sweeps
PAVG
Average of maximum frequency errors over several sweeps
PCTL
95% percentile of RMS frequency error over several sweeps
PEAK
Maximum EVM over all symbols of current sweep
PPCT
95% percentile of maximum frequency errors over several sweeps
PSD
Standard deviation of maximum frequency errors over several sweeps
RPE
Maximum value of RMS EVM over several sweeps
SDEV
Standard deviation of frequency errors over several sweeps
TPE
Maximum EVM over all display points over several sweeps
Usage: Query only
CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:FSK:MDEViation?
<type>
This command queries the results of the measurement deviation of FSK modulated signals.
Query parameters:
<type> <none>
Measurement deviation for current sweep.
AVG
Average FSK measurement deviation over several sweeps.
RPE
Peak FSK measurement deviation over several sweeps.
SDEV
Standard deviation of FSK measurement deviation.
PCTL
95 percentile value of FSK measurement deviation.
Usage: Query only
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CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:FSK:RDEViation?
<type>
This command queries the results of the reference deviation of FSK modulated signals.
Query parameters:
<type> <none>
Measurement deviation for current sweep.
AVG
Average FSK measurement deviation over several sweeps.
RPE
Peak FSK measurement deviation over several sweeps.
SDEV
Standard deviation of FSK measurement deviation.
PCTL
95 percentile value of FSK measurement deviation.
Usage: Query only
CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:GIMBalance? <type>
This command queries the results of the Gain Imbalance error measurement of digital demodulation. The output values are the same as those provided in the Modulation
Accuracy table .
Query parameters:
<type> <none>
Gain imbalance error for current sweep
AVG
Average gain imbalance error over several sweeps
RPE
Peak gain imbalance error over several sweeps
SDEV
Standard deviation of gain imbalance error
PCTL
95 percentile value of gain imbalance error
Usage: Query only
CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:IQIMbalance? <type>
This command queries the results of the I/Q imbalance error measurement of digital demodulation.
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Retrieving Results
Query parameters:
<type>
Usage:
<none>
I/Q imbalance error (for current sweep)
AVG
Average I/Q imbalance error over several sweeps
RPE
Peak I/Q imbalance error over several sweeps
SDEV
Standard deviation of I/Q imbalance error
PCTL
95 percentile value of I/Q imbalance error
Query only
CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:MERRor? <type>
This command queries the results of the magnitude error measurement of digital demodulation.
Query parameters:
<type> <none>
RMS magnitude error of display points of current sweep
AVG
Average of RMS magnitude errors over several sweeps
PAVG
Average of maximum magnitude errors over several sweeps
PCTL
95% percentile of RMS magnitude error over several sweeps
PEAK
Maximum EVM over all symbols of current sweep
PPCT
95% percentile of maximum magnitude errors over several sweeps
PSD
Standard deviation of maximum magnitude errors over several sweeps
RPE
Maximum value of RMS EVM over several sweeps
SDEV
Standard deviation of magnitude errors over several sweeps
TPE
Maximum EVM over all display points over several sweeps
Usage: Query only
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CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:MPOWer? <type>
This command queries the results of the power measurement of digital demodulation.
Query parameters:
<type> <none> power measurement (for current sweep)
AVG
Average of power measurement over several sweeps
RPE
Peak of power measurement over several sweeps
SDEV
Standard deviation of power measurement
PCTL
95 percentile value of power measurement
Usage: Query only
CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:OOFFset? <type>
This command queries the results of the I/Q offset measurement performed for digital demodulation.
Query parameters:
<type> <none>
Origin offset error (for current sweep)
AVG
Average origin offset error over several sweeps
RPE
Peak origin offset error over several sweeps
SDEV
Standard deviation of origin offset error
PCTL
95 percentile value of origin offset error
Usage: Query only
CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:PERRor? <type>
This command queries the results of the phase error measurement performed for digital demodulation.
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Query parameters:
<type> <none>
RMS phase error of display points of current sweep
AVG
Average of RMS phase errors over several sweeps
PAVG
Average of maximum phase errors over several sweeps
PCTL
95% percentile of RMS phase error over several sweeps
PEAK
Maximum EVM over all symbols of current sweep
PPCT
95% percentile of maximum phase errors over several sweeps
PSD
Standard deviation of maximum phase errors over several sweeps
RPE
Maximum value of RMS EVM over several sweeps
SDEV
Standard deviation of phase errors over several sweeps
TPE
Maximum EVM over all display points over several sweeps
Usage: Query only
CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:QERRor? <type>
This command queries the results of the Quadratur error measurement performed for digital demodulation.
Query parameters:
<type> <none> quadrature error (for current sweep)
AVG
Average quadrature error over several sweeps
RPE
Peak quadrature error over several sweeps
SDEV
Standard deviation of quadrature error
PCTL
95 percentile value of quadrature error
Usage: Query only
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CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:RHO? <type>
This command queries the results of the Rho factor measurement performed for digital demodulation.
Query parameters:
<type> <none>
Rho factor (for current sweep)
AVG
Average rho factor over several sweeps
RPE
Peak rho factor over several sweeps
SDEV
Standard deviation of rho factor
PCTL
95 percentile value of rho factor
Usage: Query only
CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:SNR? <type>
This command queries the results of the SNR error measurement performed for digital demodulation.
Query parameters:
<type>
Usage:
<none>
RMS SNR value of display points of current sweep
AVG
Average of RMS SNR values over several sweeps
PAVG
Average of maximum SNR values over several sweeps
PCTL
95% percentile of RMS SNR value over several sweeps
PEAK
Maximum EVM over all symbols of current sweep
PPCT
95% percentile of maximum SNR values over several sweeps
PSD
Standard deviation of maximum SNR values over several sweeps
RPE
Maximum value of RMS EVM over several sweeps
SDEV
Standard deviation of SNR values over several sweeps
TPE
Maximum EVM over all display points over several sweeps
Query only
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CALCulate<n>:MARKer<m>:FUNCtion:DDEMod:STATistic:SRERror? <type>
This command queries the symbol rate error
Query parameters:
<type> PEAK | AVG | SDEV | PCTL | TPEak | RPEak | PAVG | PSDev |
PPCTl
<none>
Symbol rate error (for current sweep)
AVG
Average symbol rate error over several sweeps
RPE
Peak symbol rate error over several sweeps
SDEV
Standard deviation of symbol rate error
PCTL
95 percentile value of symbol rate error
Usage: Query only
11.9.4 Retrieving Limit Check Results
The modulation accuracy parameters can be checked against defined limits. The following commands are required to query the results of these limit checks.
CALCulate<n>:LIMit:MACCuracy:CFERror:CURRent[:RESult]?
CALCulate<n>:LIMit:MACCuracy:CFERror:MEAN[:RESult]?
CALCulate<n>:LIMit:MACCuracy:CFERror:PEAK[:RESult]?
CALCulate<n>:LIMit:MACCuracy:EVM:PCURrent[:RESult]?
CALCulate<n>:LIMit:MACCuracy:EVM:PMEan[:RESult]?
CALCulate<n>:LIMit:MACCuracy:EVM:PPEak[:RESUlt]?
CALCulate<n>:LIMit:MACCuracy:EVM:RCURrent[:RESult]?
CALCulate<n>:LIMit:MACCuracy:EVM:RMEan[:RESult]?
CALCulate<n>:LIMit:MACCuracy:EVM:RPEak[:RESult]?
CALCulate<n>:LIMit:MACCuracy:FDERror:CURRent[:RESult]?
CALCulate<n>:LIMit:MACCuracy:FDERror:MEAN[:RESult]?
CALCulate<n>:LIMit:MACCuracy:FDERror:PEAK[:RESult]?
CALCulate<n>:LIMit:MACCuracy:FERRor:PCURrent[:RESUlt]?
CALCulate<n>:LIMit:MACCuracy:FERRor:PMEan[:RESult]?
CALCulate<n>:LIMit:MACCuracy:FERRor:PPEak[:RESult]?
CALCulate<n>:LIMit:MACCuracy:FERRor:RCURrent[:RESult]?
CALCulate<n>:LIMit:MACCuracy:FERRor:RMEan[:RESult]?
CALCulate<n>:LIMit:MACCuracy:FERRor:RPEak[:RESult]?
CALCulate<n>:LIMit:MACCuracy:MERRor:PCURrent[:RESult]?
CALCulate<n>:LIMit:MACCuracy:MERRor:PMEan[:RESult]?
CALCulate<n>:LIMit:MACCuracy:MERRor:PPEak[:RESult]?
CALCulate<n>:LIMit:MACCuracy:MERRor:RCURrent[:RESult]?
CALCulate<n>:LIMit:MACCuracy:MERRor:RMEan[:RESult]?
CALCulate<n>:LIMit:MACCuracy:MERRor:RPEak[:RESult]?
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CALCulate<n>:LIMit:MACCuracy:OOFFset:CURRent[:RESult]?
CALCulate<n>:LIMit:MACCuracy:OOFFset:MEAN[:RESult]?
CALCulate<n>:LIMit:MACCuracy:OOFFset:PEAK[:RESult]?
CALCulate<n>:LIMit:MACCuracy:PERRor:PCURrent[:RESult]?
CALCulate<n>:LIMit:MACCuracy:PERRor:PMEan[:RESult]?
CALCulate<n>:LIMit:MACCuracy:PERRor:PPEak[:RESult]?
CALCulate<n>:LIMit:MACCuracy:PERRor:RCURrent[:RESult]?
CALCulate<n>:LIMit:MACCuracy:PERRor:RMEan[:RESult]?
CALCulate<n>:LIMit:MACCuracy:PERRor:RPEak[:RESult]?
CALCulate<n>:LIMit:MACCuracy:RHO:CURRent[:RESult]?
CALCulate<n>:LIMit:MACCuracy:RHO:MEAN[:RESult]?
CALCulate<n>:LIMit:MACCuracy:RHO:PEAK[:RESult]?
CALCulate<n>:LIMit:MACCuracy:<ResultType>:<LimitType>[:RESUlt]
This command queries whether the limit for the specified result type and limit type was violated.
For details on result types and limit types see chapter 3.2.29, "Result Summary" , on page 47.
Suffix:
<ResultType>
.
CFERror | EVM | FDERror | FERRor | MERRor | OOFFset |
PERRor | RHO
CFERror = Carrier Frequency Error
EVM = Error Vector Magnitude
FDERror = Frequency deviation error (FSK only)
FERRor = Frequency error (FSK only)
MERRor = Magnitude Error
OOFFset = I/Q Offset
PERRor = Phase Error
RHO = Rho
<LimitType> CURRent | MEAN | PEAK | PCURRent | PMEan | PPEak |
RCURRent | RMEan | RPEak
For CFERor, OOFFset, RHO:
CURRent
MEAN
PEAK
For EVM, FDERror, FERRor, MERRor, PERRor:
PCURRent = Peak current value
PMEan = Peak mean value
PPEak = Peak peak value
RCURRent = RMS current value
RMEan = RMS mean value
RPEak = RMS peak value
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Importing and Exporting I/Q Data and Results
Return values:
<LimitResult> NONE | PASS | FAIL | MARGIN
NONE
No limit check result available yet.
PASS
All values have passed the limit check.
FAIL
At least one value has exceeded the limit.
MARGIN currently not used
*RST: NONE
11.10 Importing and Exporting I/Q Data and Results
The I/Q data to be evaluated in the VSA application can not only be measured by the
VSA application itself, it can also be imported to the application, provided it has the correct format. Furthermore, the evaluated I/Q data from the VSA application can be exported for further analysis in external applications.
For details on importing and exporting I/Q data see
chapter 7, "I/Q Data Import and
MMEMory:LOAD:IQ:STATe 1,<FileName>
This command restores I/Q data from a file.
The file extension is *.iq.tar.
Parameters:
<FileName>
Example:
String containing the path and name of the source file.
MMEM:LOAD:IQ:STAT 1, 'C:
\R_S\Instr\user\data.iq.tar'
Loads IQ data from the specified file.
Usage: Setting only
Manual operation: See
MMEMory:STORe<n>:IQ:COMMent <Comment>
This command adds a comment to a file that contains I/Q data.
The suffix <n> is irrelevant.
Parameters:
<Comment> String containing the comment.
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Status Reporting System
Example: MMEM:STOR:IQ:COMM 'Device test 1b'
Creates a description for the export file.
MMEM:STOR:IQ:STAT 1, 'C:
\R_S\Instr\user\data.iq.tar'
Stores I/Q data and the comment to the specified file.
Manual operation: See
MMEMory:STORe<n>:IQ:STATe 1, <FileName>
This command writes the captured I/Q data to a file.
The suffix <n> is irrelevant.
The file extension is *.iq.tar. By default, the contents of the file are in 32-bit floating point format.
Secure User Mode
In secure user mode, settings that are to be stored on the instrument are stored to volatile memory, which is restricted to 256 MB. Thus, a "Memory full" error may 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 User Manual.
Parameters:
1
<FileName>
Example:
String containing the path and name of the target file.
MMEM:STOR:IQ:STAT 1, 'C:
\R_S\Instr\user\data.iq.tar'
Stores the captured I/Q data to the specified file.
Manual operation: See
11.11 Status Reporting System
The status reporting system stores all information on the current operating state of the instrument, e.g. information on errors or limit violations which have occurred. This information is stored in the status registers and in the error queue. The status registers and the error queue can be queried via IEC bus.
In this section, only the status registers/bits specific to the VSA application are described.
For details on the common R&S FPS status registers refer to the description of remote control basics in the R&S FPS User Manual.
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Status Reporting System
*RST does not influence the status registers.
Description of the Status Registers
In addition to the registers provided by the base system, the following registers are used in the VSA application:
● STATus:QUEStionable:SYNC<n> - contains application-specific information about synchronization errors or errors during burst detection.
● STATus:QUESTionable:MODulation<n> – provides information on any limit violations that occur after demodulation in one of the 4 windows
● STATus:QUESTionable:MODulation<n>:EVM - limit violations in EVM evaluation
● STATus:QUESTionable:MODulation<n>:PHASe - limit violations in Phase
Error evaluation
● STATus:QUESTionable:MODulation<n>:MAGnitude - limit violations in Magnitude Error evaluation
● STATus:QUESTionable:MODulation<n>:CFRequency - limit violations in Carrier Frequency evaluation
● STATus:QUESTionable:MODulation<n>:IQRHO - limit violations in I/Q-Offset and RHO evaluation
● STATus:QUESTionable:MODulation<n>:FSK - limit violations in FSK evaluation
The STATus:QUEStionable register "sums up" the information from all subregisters
(e.g. bit 11 sums up the information for all STATus:QUEStionable:SYNC registers).
For some subregisters, there may be separate registers for each active channel. Thus, if a status bit in the STATus:QUEStionable register indicates an error, the error may have occurred in any of the channel-specific subregisters. In this case, you must check the subregister of each channel to determine which channel caused the error. By default, querying the status of a subregister always returns the result for the currently selected channel.
The commands to query the contents of the following status registers are described in
chapter 11.11.9, "Querying the Status Registers" , on page 397.
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Fig. 11-2: Overview of VSA-specific status registers
● STATus:QUEStionable:SYNC<n> Register ..........................................................394
● STATus:QUEStionable:MODulation<n> Register .................................................394
● STATus:QUESTionable:MODulation<n>:EVM Register .......................................394
● STATus:QUESTionable:MODulation<n>:PHASe Register ...................................395
● STATus:QUESTionable:MODulation<n>:MAGnitude Register .............................395
● STATus:QUESTionable:MODulation<n>:CFRequency Register ..........................396
● STATus:QUESTionable:MODulation<n>:IQRHO Register ...................................396
● STATus:QUESTionable:MODulation<n>:FSK Register ........................................397
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11.11.1 STATus:QUEStionable:SYNC<n> Register
This register contains application-specific information about synchronization errors or errors during burst detection for each window in each VSA channel. It can be queried
with commands STATus:QUEStionable:SYNC:CONDition?
STATus:QUEStionable:SYNC[:EVENt]?
Table 11-4: Status error bits in STATus:QUEStionable:SYNC register for R&S FPS-K70
Bit Definition
0 Burst not found.
This bit is set if a burst could not be detected.
1
2 to 14
15
Sync not found
This bit is set if the sync sequence (pattern) of the midamble could not be detected.
Not used.
This bit is always 0.
11.11.2 STATus:QUEStionable:MODulation<n> Register
This register comprises information about any limit violations that may occur after demodulation in any of the VSA windows. It can be queried with commands
QUEStionable:MODulation<n>:CONDition?
QUEStionable:MODulation<n>[:EVENt]?
The status of the STATus:QUESTionable:MODulation register is indicated in bit 7 of the "STATus:QUESTionable" register. It can be queried using the
STATus:QUESTionable:EVENt command.
1
2
3
4
Bit No
0
5
6-15
Meaning
Error in EVM evaluation
Error in Phase Error evaluation
Error in Magnitude Error evaluation
Error in Carrier Frequency evaluation
Error in I/Q offset or RHO evaluation
Error in FSK evaluation
These bits are not used
11.11.3 STATus:QUESTionable:MODulation<n>:EVM Register
This register comprises information about limit violations in EVM evaluation. It can be queried with commands
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STATus:QUEStionable:MODulation<n>:EVM:CONDition and
STATus:QUEStionable:MODulation<n>:EVM[:EVENt].
3-4
5
6
7
8-15
1
2
Bit No
0
Meaning
Error in current RMS value
Error in mean RMS value
Error in peak RMS value
These bits are not used
Error in current peak value
Error in mean peak value
Error in peak peak value
These bits are not used
11.11.4 STATus:QUESTionable:MODulation<n>:PHASe Register
This register comprises information about limit violations in Phase Error evaluation. It can be queried with commands
STATus:QUEStionable:MODulation<n>:PHASe:CONDition and
STATus:QUEStionable:MODulation<n>:PHASe[:EVENt].
5
6
2
3-4
Bit No
0
1
7
8-15
Meaning
Error in current RMS value
Error in mean RMS value
Error in peak RMS value
These bits are not used
Error in current peak value
Error in mean peak value
Error in peak peak value
These bits are not used
11.11.5 STATus:QUESTionable:MODulation<n>:MAGnitude Register
This register comprises information about limit violations in Magnitude Error evaluation.
It can be queried with commands
STATus:QUEStionable:MODulation<n>:MAGNitude:CONDition and
STATus:QUEStionable:MODulation<n>:MAGNitude[:EVENt].
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3-4
5
6
7
8-15
1
2
Bit No
0
Meaning
Error in current RMS value
Error in mean RMS value
Error in peak RMS value
These bits are not used
Error in current peak value
Error in mean peak value
Error in peak peak value
These bits are not used
11.11.6 STATus:QUESTionable:MODulation<n>:CFRequency Register
This register comprises information about limit violations in Carrier Frequency evaluation. It can be queried with commands
STATus:QUEStionable:MODulation<n>:CFREQuency:CONDition and
STATus:QUEStionable:MODulation<n>:CFREQuency[:EVENt].
1
2
Bit No
0
3-15
Meaning
Error in current value
Error in mean value
Error in peak value
These bits are not used
11.11.7 STATus:QUESTionable:MODulation<n>:IQRHO Register
This register comprises information about limit violations in I/Q offset or RHO evaluation. It can be queried with commands
STATus:QUEStionable:MODulation<n>:IQRHO:CONDition and
STATus:QUEStionable:MODulation<n>:IQRHO[:EVENt].
5
6
Bit No
0
1
2
3-4
Meaning
Error in current RHO value
Error in mean RHO value
Error in peak RHO value
These bits are not used
Error in current I/Q offset value
Error in mean I/Q offset value
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Bit No
7
8-15
Meaning
Error in peak I/Q offset value
These bits are not used
11.11.8 STATus:QUESTionable:MODulation<n>:FSK Register
This register comprises information about limit violations in FSK evaluation. It can be queried with commands
STATus:QUEStionable:MODulation<n>:FSK:CONDition and
STATus:QUEStionable:MODulation<n>:FSK[:EVENt].
5
6
7
8-9
10
11
12
13-15
Bit No
0
1
2
3-4
Meaning
Error in current Frequency Error RMS value
Error in mean Frequency Error RMS value
Error in peak Frequency Error RMS value
These bits are not used
Error in current Frequency Error peak value
Error in mean Frequency Error peak value
Error in peak Frequency Error peak value
These bits are not used
Error in current Frequency Deviation value
Error in mean Frequency Deviation value
Error in peak Frequency Deviation value
These bits are not used
11.11.9 Querying the Status Registers
The following commands query the contents of the individual status registers.
STATus:QUEStionable:ACPLimit:CONDition?
...................................................................399
STATus:QUEStionable:DIQ:CONDition?
.......................................................................... 399
STATus:QUEStionable:FREQuency:CONDition?
.............................................................. 399
STATus:QUEStionable:LIMit<m>:CONDition?
...................................................................399
STATus:QUEStionable:LMARgin<m>:CONDition?
............................................................ 399
STATus:QUEStionable:MODulation<n>:CONDition?
......................................................... 399
STATus:QUEStionable:MODulation<n>:CFRequency:CONDition?
......................................399
STATus:QUEStionable:MODulation<n>:EVM:CONDition?
................................................. 399
STATus:QUEStionable:MODulation<n>:FSK:CONDition?
.................................................. 399
STATus:QUEStionable:MODulation<n>:IQRHo:CONDition?
...............................................399
STATus:QUEStionable:MODulation<n>:MAGNitude:CONDition?
........................................399
STATus:QUEStionable:MODulation<n>:PHASe:CONDition?
..............................................399
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STATus:QUEStionable:POWer:CONDition?
..................................................................... 399
STATus:QUEStionable:SYNC:CONDition?
....................................................................... 399
STATus:QUEStionable:ACPLimit[:EVENt]?
.......................................................................399
STATus:QUEStionable:DIQ[:EVENt]?
.............................................................................. 399
STATus:QUEStionable:FREQuency[:EVENt]?
.................................................................. 399
STATus:QUEStionable:LIMit<m> [:EVENt]?
......................................................................399
STATus:QUEStionable:LMARgin<m>[:EVENt]?
................................................................ 399
STATus:QUEStionable:MODulation<n>[:EVENt]?
............................................................. 399
STATus:QUEStionable:MODulation<n>:CFRequency[:EVENt]?
..........................................399
STATus:QUEStionable:MODulation<n>:EVM[:EVENt]?
..................................................... 399
STATus:QUEStionable:MODulation<n>:FSK[:EVENt]?
...................................................... 399
STATus:QUEStionable:MODulation<n>:IQRHo[:EVENt]?
...................................................399
STATus:QUEStionable:MODulation<n>:MAGNitude[:EVENt]?
............................................399
STATus:QUEStionable:MODulation<n>:PHASe[:EVENt]?
..................................................399
STATus:QUEStionable:POWer[:EVENt]?
......................................................................... 400
STATus:QUEStionable:SYNC[:EVENt]?
........................................................................... 400
STATus:QUEStionable:MODulation<n>:CFRequency:ENABle ........................................... 400
STATus:QUEStionable:MODulation<n>:MAGNitude:ENABle ..............................................400
STATus:QUEStionable:MODulation<n>:CFRequency:NTRansition ..................................... 401
STATus:QUEStionable:MODulation<n>:MAGNitude:NTRansition ....................................... 401
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STATus:QUEStionable:MODulation<n>:CFRequency:PTRansition ..................................... 401
STATus:QUEStionable:MODulation<n>:MAGNitude:PTRansition ....................................... 401
STATus:QUEStionable:ACPLimit:CONDition? <ChannelName>
STATus:QUEStionable:DIQ:CONDition? <ChannelName>
STATus:QUEStionable:FREQuency:CONDition? <ChannelName>
STATus:QUEStionable:LIMit<m>:CONDition? <ChannelName>
STATus:QUEStionable:LMARgin<m>:CONDition? <ChannelName>
STATus:QUEStionable:MODulation<n>:CONDition? <ChannelName>
STATus:QUEStionable:MODulation<n>:CFRequency:CONDition?
<ChannelName>
STATus:QUEStionable:MODulation<n>:EVM:CONDition? <ChannelName>
STATus:QUEStionable:MODulation<n>:FSK:CONDition? <ChannelName>
STATus:QUEStionable:MODulation<n>:IQRHo:CONDition? <ChannelName>
STATus:QUEStionable:MODulation<n>:MAGNitude:CONDition? <ChannelName>
STATus:QUEStionable:MODulation<n>:PHASe:CONDition? <ChannelName>
STATus:QUEStionable:POWer:CONDition? <ChannelName>
STATus:QUEStionable:SYNC:CONDition? <ChannelName>
This command reads out the CONDition section of the status register.
The command does not delete the contents of the EVENt section.
Query parameters:
<ChannelName> String containing the name of the channel.
The parameter is optional. If you omit it, the command works for the currently active channel.
Usage: Query only
STATus:QUEStionable:ACPLimit[:EVENt]? <ChannelName>
STATus:QUEStionable:DIQ[:EVENt]? <ChannelName>
STATus:QUEStionable:FREQuency[:EVENt]? <ChannelName>
STATus:QUEStionable:LIMit<m> [:EVENt]? <ChannelName>
STATus:QUEStionable:LMARgin<m>[:EVENt]? <ChannelName>
STATus:QUEStionable:MODulation<n>[:EVENt]? <ChannelName>
STATus:QUEStionable:MODulation<n>:CFRequency[:EVENt]? <ChannelName>
STATus:QUEStionable:MODulation<n>:EVM[:EVENt]? <ChannelName>
STATus:QUEStionable:MODulation<n>:FSK[:EVENt]? <ChannelName>
STATus:QUEStionable:MODulation<n>:IQRHo[:EVENt]? <ChannelName>
STATus:QUEStionable:MODulation<n>:MAGNitude[:EVENt]? <ChannelName>
STATus:QUEStionable:MODulation<n>:PHASe[:EVENt]? <ChannelName>
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STATus:QUEStionable:POWer[:EVENt]? <ChannelName>
STATus:QUEStionable:SYNC[:EVENt]? <ChannelName>
This command reads out the EVENt section of the status register.
The command also deletes the contents of the EVENt section.
Query parameters:
<ChannelName> String containing the name of the channel.
The parameter is optional. If you omit it, the command works for the currently active channel.
Usage: Query only
STATus:QUEStionable:ACPLimit:ENABle <BitDefinition>, <ChannelName>
STATus:QUEStionable:DIQ:ENABle <BitDefinition>, <ChannelName>
STATus:QUEStionable:FREQuency:ENABle <BitDefinition>, <ChannelName>
STATus:QUEStionable:LIMit<m>:ENABle <BitDefinition>, <ChannelName>
STATus:QUEStionable:LMARgin<m>:ENABle <BitDefinition>, <ChannelName>
STATus:QUEStionable:MODulation<n>:ENABle <BitDefinition>, <ChannelName>
STATus:QUEStionable:MODulation<n>:CFRequency:ENABle <BitDefinition>,
<ChannelName>
STATus:QUEStionable:MODulation<n>:EVM:ENABle <BitDefinition>,
<ChannelName>
STATus:QUEStionable:MODulation<n>:FSK:ENABle <BitDefinition>,
<ChannelName>
STATus:QUEStionable:MODulation<n>:IQRHo:ENABle <BitDefinition>,
<ChannelName>
STATus:QUEStionable:MODulation<n>:MAGNitude:ENABle <BitDefinition>,
<ChannelName>
STATus:QUEStionable:MODulation<n>:PHASe:ENABle <BitDefinition>,
<ChannelName>
STATus:QUEStionable:POWer:ENABle <BitDefinition>
STATus:QUEStionable:SYNC:ENABle <BitDefinition>, <ChannelName>
This command controls the ENABle part of a register.
The ENABle part allows true conditions in the EVENt part of the status register to be reported in the summary bit. If a bit is 1 in the enable register and its associated event bit transitions to true, a positive transition will occur in the summary bit reported to the next higher level.
Parameters:
<BitDefinition>
<ChannelName>
Range: 0 to 65535
String containing the name of the channel.
The parameter is optional. If you omit it, the command works for the currently active channel.
STATus:QUEStionable:ACPLimit:NTRansition <BitDefinition>, <ChannelName>
STATus:QUEStionable:DIQ:NTRansition <BitDefinition>,<ChannelName>
STATus:QUEStionable:FREQuency:NTRansition <BitDefinition>, <ChannelName>
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STATus:QUEStionable:LIMit<m>:NTRansition <BitDefinition>, <ChannelName>
STATus:QUEStionable:LMARgin<m>:NTRansition <BitDefinition>,
<ChannelName>
STATus:QUEStionable:MODulation<n>:NTRansition <BitDefinition>,
<ChannelName>
STATus:QUEStionable:MODulation<n>:CFRequency:NTRansition <BitDefinition>,
<ChannelName>
STATus:QUEStionable:MODulation<n>:EVM:NTRansition <BitDefinition>,
<ChannelName>
STATus:QUEStionable:MODulation<n>:FSK:NTRansition <BitDefinition>,
<ChannelName>
STATus:QUEStionable:MODulation<n>:IQRHo:NTRansition <BitDefinition>,
<ChannelName>
STATus:QUEStionable:MODulation<n>:MAGNitude:NTRansition <BitDefinition>,
<ChannelName>
STATus:QUEStionable:MODulation<n>:PHASe:NTRansition <BitDefinition>,
<ChannelName>
STATus:QUEStionable:POWer:NTRansition <BitDefinition>, <ChannelName>
STATus:QUEStionable:SYNC:NTRansition <BitDefinition>,<ChannelName>
This command controls the Negative TRansition part of a register.
Setting a bit causes a 1 to 0 transition in the corresponding bit of the associated register. The transition also writes a 1 into the associated bit of the corresponding EVENt register.
Parameters:
<BitDefinition>
<ChannelName>
Range: 0 to 65535
String containing the name of the channel.
The parameter is optional. If you omit it, the command works for the currently active channel.
STATus:QUEStionable:ACPLimit:PTRansition <BitDefinition>, <ChannelName>
STATus:QUEStionable:DIQ:PTRansition <BitDefinition>,<ChannelName>
STATus:QUEStionable:FREQuency:PTRansition <BitDefinition>, <ChannelName>
STATus:QUEStionable:LIMit<m>:PTRansition <BitDefinition>, <ChannelName>
STATus:QUEStionable:LMARgin<m>:PTRansition <BitDefinition>,
<ChannelName>
STATus:QUEStionable:MODulation<n>:PTRansition <BitDefinition>,
<ChannelName>
STATus:QUEStionable:MODulation<n>:CFRequency:PTRansition <BitDefinition>,
<ChannelName>
STATus:QUEStionable:MODulation<n>:EVM:PTRansition <BitDefinition>,
<ChannelName>
STATus:QUEStionable:MODulation<n>:FSK:PTRansition <BitDefinition>,
<ChannelName>
STATus:QUEStionable:MODulation<n>:IQRHo:PTRansition <BitDefinition>,
<ChannelName>
STATus:QUEStionable:MODulation<n>:MAGNitude:PTRansition <BitDefinition>,
<ChannelName>
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STATus:QUEStionable:MODulation<n>:PHASe:PTRansition <BitDefinition>,
<ChannelName>
STATus:QUEStionable:POWer:PTRansition <BitDefinition>, <ChannelName>
STATus:QUEStionable:SYNC:PTRansition <BitDefinition>,<ChannelName>
These commands control the Positive TRansition part of a register.
Setting a bit causes a 0 to 1 transition in the corresponding bit of the associated register. The transition also writes a 1 into the associated bit of the corresponding EVENt register.
Parameters:
<BitDefinition>
<ChannelName>
Range: 0 to 65535
String containing the name of the channel.
The parameter is optional. If you omit it, the command works for the currently active channel.
11.12 Commands for Compatibility
The following commands are maintained for compatibility reasons with previous R&S analyzers only. Use the specified alternative commands for new remote control programs.
CALCulate<n>:FSK:DEViation:COMPensation <RefDevComp>
This command defines whether the deviation error is compensated for when calculating the frequency error for FSK modulation.
Note that this command is maintained for compatibility reasons only. For newer remote
programs, use [SENSe:]DDEMod:NORMalize:FDERror on page 324.
Setting parameters:
<RefDevComp> ON | OFF | 1 | 0
ON
Scales the reference signal to the actual deviation of the measurement signal.
OFF
Uses the entered nominal deviation for the reference signal.
*RST: 1
[SENSe:]DDEMod:NORMalize[:VALue] <Normalize>
This command switches the compensation of the IQ offset and the compensation of amplitude droop on or off.
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Note that this command is maintained for compatibility reasons only. Use the more specific [SENSe:]DDEMod:NORMalize commands for new remote control programs
(see chapter 11.5.8, "Demodulation Settings" , on page 318).
Setting parameters:
<Normalize> ON | OFF | 1 | 0
OFF
No compensation for amplitude droop nor I/Q offset
ON
Compensation for amplitude droop and I/Q offset enabled
*RST: 1
[SENSe:]DDEMod:SBANd <SidebandPos>
This command selects the sideband for the demodulation.
Note that this command is maintained for compatibility reasons only. Use the
SENS:SWAP:IQ command for new remote control programs (see
Setting parameters:
<SidebandPos> NORMal | INVerse
NORMal
Normal (non-inverted) position
INVerse
Inverted position
*RST: NORMal
11.13 Programming Examples
The following examples demonstrate how to perform vector signal analysis in a remote environment.
These examples are meant to demonstrate the use of the most common remote commands for vector signal analysis. Note that not all commands executed here are actually necessary, as they may reflect default settings.
● Measurement Example 1: User-defined Measurement of Continuous QPSK Signal
● Measurement Example 2: GSM EDGE Burst Measurement Based on a Digital
● Measurement Example 3: User-Defined Pattern Search and Limit Check ........... 409
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11.13.1 Measurement Example 1: User-defined Measurement of Continuous QPSK Signal
The following example describes a scenario similar to the one for manual operation described in
chapter 9.2, "Measurement Example 1: Continuous QPSK Signal" , on page 228.
//-----------Configuring the measurement ------------
*RST
//Reset the instrument
FREQ:CENT 1GHz
//Set the center frequency.
DISP:TRAC:Y:RLEV 4dBm
//Set the reference level
INST:CRE:NEW DDEM,'MyVSA'
//Create new measurement channel for vector signal analysis named "MyVSA"
//--------- Configuring the expected input signal ---------------
DDEM:FORM QPSK
//Set the modulation type
DDEM:QPSK:FORM NORM
//Set the modulation order
DDEM:MAPP:CAT?
//Query the available symbol mappings for QPSK modulation
DDEM:MAPP 'WCDMA'
//Set the symbol mapping to WCDMA
DDEM:SRAT 1 MHz
//Set the symbol rate
DDEM:TFIL:NAME 'RRC'
DDEM:TFIL:ALPH 0.35
//Select the RRC transmit filter
//--------- Configuring an averaged EVM vs Time result display ---------
LAY:ADD? '1',RIGH,EVEC
//Create new window to the right of I/Q constellation (window 1) with
//error vector as data type
//Result: '5'
CALC5:FORM MAGN
//Set result type for window 5 to magnitude = EVM
DISPlay:WINDow5:TRACe2:MODE AVER
//Add a second trace in average mode
DISPlay:WINDow5:TRACe3:MODE MAXH
//Add a third trace in max hold mode
SWE:COUN 10
//Calculate an average over 10 sweeps
//--------------Performing the measurement-----
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INIT:CONT OFF
//Select single sweep mode.
INIT;*WAI
//Initiate a new measurement and wait until the 10 sweeps have finished.
//-----Storing the Constellation I/Q diagram to a file ------
DISP:WIND1:SIZE LARG
//Display the I/Q Constellation result display (window 1) in full screen.
HCOP:DEST 'MMEM'
//Define the destination of the screenshot as a file.
HCOP:DEV:LANG BMP
//Select bmp as the file format.
MMEM:NAME 'C:\R_S\INST\USER\IQConstellation.bmp'
//Select the file name for the printout.
HCOP:ITEM:ALL
//Print all screen elements
HCOP
//Store the printout in a file called 'IQConstellation.bmp'.
DISP:WIND5:SIZE SMAL
//Restore the I/Q Constellation result display to one subwindow.
//------------Storing the EVM trace data to a file---------------
FORM:DEXP:HEAD ON
//Include a header in the trace export file
FORM:DEXP:MODE TRAC
//Export the trace data, not raw I/Q data
MMEM:STOR4:TRAC 1,'AverageEVM'
//Save the detected symbol values (x-values are not exported with trace data)
//Results:
MMEM:STOR5:TRAC 1,'AverageEVM'
//Save the EVM values (window 5) to an ascii file.
//Results:
//
11.13.2 Measurement Example 2: GSM EDGE Burst Measurement Based on a Digital Standard
The following example describes a scenario similar to the one for manual operation described in
chapter 9.3, "Measurement Example 2: Burst GSM EDGE Signals" , on page 235
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Note that although this example uses the settings from a predefined digital standard, the configuration is changed to demonstrate the possibilities of the VSA application. A measurement that is performed strictly according to the standard requires much less programming efforts.
The rising and falling edges of a GSM burst are analyzed using the following result range settings:
//-----------Configuring the measurement ------------
*RST
//Reset the instrument
FREQ:CENT 1GHz
//Set the center frequency.
DISP:TRAC:Y:RLEV 4dBm
//Set the reference level
INST:CRE:NEW DDEM,'VSA'
//Create new measurement channel for vector signal analysis named "VSA"
//-------Loading the required digital standard -----------------
DDEM:PRES 'EDGE_NB'
//Loads the GSM EDGE_8PSK standard file and the settings defined there
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//------Changing data acquisition settings --------------------
DDEM:RLEN 10000 sym
//-------- Defining the result range ---------------
DDEMod:TIME 200
//Defines the result length as 200 symbols.
CALC:TRAC:ADJ BURS
//Defines the burst as the reference for the result range
CALC:TRAC:ADJ:ALIG LEFT
//Aligns the result range to the left edge of the burst
CALC:TRAC:ADJ:ALIG:OFFS -10
//Defines an offset of 10 symbols from the burst start
DISP:TRAC:X:VOFF 10
//Defines the symbol number 10 as the result range start
//----------Defining the evaluation range ---------
CALC:ELIN:STAT ON
CALC:ELIN1 10
CALC:ELIN2 190
//Evaluation range starts at symbol 10 and ends at symbol 190
//--------- Changing the result display ---------
LAY:WIND4:REM
//Close symbol table display (window 4)
DISPlay:WINDow1:TRACe2:MODE MAXH
//Add a second trace in max hold mode to EVM vs Time display (window 1)
LAY:ADD? '3',RIGH,MEAS
//Create new window to the right of capture buffer (window 3) with
//measurement signal as data type
//Result: '4'
CALC4:FORM MAGN
//Set result type for window 4 to magnitude
DISPlay:WINDow4:TRACe2:MODE WRIT
CALC4:TRAC2 REF
//Add a second trace in clear/write mode for the reference signal
//-------- Activating limit checks for modulation accuracy ---------
CALC:LIM:MACC:STAT ON
//Activates limit checks for all values in the Result Summary
//--------------Performing the measurement -----
INIT:CONT OFF
//Select single sweep mode.
INIT;*WAI
//Initiate a new measurement and wait until the 10 sweeps have finished.
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//----- Retrieving Results ------
CALC2:MARK:FUNC:DDEM:STAT:EVM? AVG
CALC:LIM:MACC:EVM:RCUR?
//Query the value and check the limit for the EVM RMS value in the
//result summary for the current evaluation range
//Result:
CALC2:MARK:FUNC:DDEM:STAT:EVM? PAVG
CALC:LIM:MACC:EVM:PPE?
//Query the value and check the limit for the largest error vector magnitude
//in the measurement.
//Result:
CALC2:MARK:FUNC:DDEM:STAT:CFER? AVG
CALC:LIM:MACC:CFER:MEAN?
//Query the value and check the limit for the mean carrier frequency offset
//in the result summary for the current evaluation range
//Result:
//------- Storing trace data to a file ---------------
FORM:DEXP:HEAD ON
//Include a header in the trace export file
FORM:DEXP:MODE TRAC
//Export the trace data, not raw I/Q data
DISP:WIND1:TRAC2:X:STAR?
//Query the first value of the x-axis for the current result range
//(x-values are not exported with trace data)
//Result:
MMEM:STOR4:TRAC 1,'Measurement signal'
//Save the measurement signal values (trace 1 in window 4) to an ascii file.
//Results:
//
MMEM:STOR4:TRAC 2,'Reference signal'
//Save the reference signal values (trace 2 in window 4) to an ascii file.
//Results:
//
MMEM:STOR2:TRAC 1,'Result Summary'
//Save the result summary values (window 2) for the current result range
//to an ascii file.
//Results:
//
//-------- Retrieving results for further result ranges -------->
DDEM:SEAR:MBUR:CALC?
//Query the number of result ranges (current is last)
//Use variable <x> to determine number of previous result range
//DDEM:SEAR:MBUR:CALC <x>
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Programming Examples
//Move to next result range and repeat section "retrieving results" for
//range-specific results
11.13.3 Measurement Example 3: User-Defined Pattern Search and Limit
Check
In this example a user-defined pattern is used to detect bursts and the calculated measurement results are checked against defined limits. The configuration settings are stored as a user-defined standard.
//-----------Configuring the measurement ------------
*RST
//Reset the instrument
FREQ:CENT 1GHz
//Set the center frequency.
DISP:TRAC:Y:RLEV 4dBm
//Set the reference level
INST:CRE:NEW DDEM,'VSA'
//Create new measurement channel for vector signal analysis named "VSA"
//----------------- Creating a pattern ------------------
DDEM:SEAR:SYNC:NAME 'EDGE_TSC_CUST'
//Create new pattern
DDEM:SEAR:SYNC:NST 4
DDEM:SEAR:SYNC:DATA '00030001000000000003000200020001000300010001'
DDEM:SEAR:SYNC:COMM 'Customized pattern'
DDEM:SEAR:SYNC:TEXT 'Special edge normal Burst'
DDEM:SEAR:SYNC:NAME 'EDGE_TSC_CUST'
//Store customized pattern
DDEM:SEAR:SYNC:PATT:ADD 'EDGE_TSC_CUST'
//Add new pattern to current standard
//--------- Configuring the expected input signal ---------------
DDEM:FORM QPSK
//Set the modulation type
DDEM:QPSK:FORM NORM
//Set the modulation order
DDEM:MAPP:CAT?
//Query the available symbol mappings for QPSK modulation
DDEM:MAPP 'WCDMA'
//Set the symbol mapping to WCDMA
DDEM:SRAT 1 MHz
//Set the symbol rate
DDEM:SIGN BURS
//Define input signal as burst signal
DDEM:SIGN:PATT ON
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Programming Examples
//Enable pattern search
DDEM:SEAR:SYNC:CAT? CURR
//Query the names of all defined patterns assigned to the current standard
DDEM:SEAR:SYNC:SEL 'EDGE_TSC_CUST'
//Select a pattern
DDEM:STAN:SYNC:OFFS 10
//Ignore the first 10 symbols of the signal before comparing pattern
DDEM:STAN:SYNC:OFFS:STAT ON
DDEM:SEAR:SYNC:STAT ON
//------ Storing the new settings as a user-defined standard -------------
DDEM:STAN:SAVE 'C:\TEMP\CustomizedBurstMeas'
//--------------Performing the measurement -----
INIT:CONT OFF
//Select single sweep mode.
INIT;*WAI
//Initiate a new measurement and wait until it has finished.
//----- Retrieving Results ------
TRAC3:DATA? TRACE1
//Query the trace results of the capture buffer display.
//Results:
//
TRAC2:DATA? TRACE1
//Query the results of the result summary.
//Results:
//
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R&S ® FPS-K70 Annex
Abbreviations
A Annex
The following sections are provided for reference purposes and include detailed information such as formulae and abbreviations.
A.1 Abbreviations
The following abbreviations are commonly used in the description of the R&S FPS-K70 option.
Abbreviation
FSK
ISI
ISI-free demodulation
MEAS filter
MSK
NDA Demodulator
PSK
QAM
Meaning See section
Frequency Shift Keying
Modulation mode for which the information is encrypted in the frequency.
Frequency Shift Keying (FSK)
Inter-symbol Interference
System-Theoretical Modulation and Demodulation Filters
Demodulation structure in which the signal is no longer influenced by adjacent symbols at the decision instants after signal-adapted filtering.
Measurement Filter
Weighting filter for the measurement.
System-Theoretical Modulation and Demodulation Filters
Minimum Shift Keying
Modulation mode.
Non Data Aided Demodulator
Demodulation without any knowledge of the sent data contents.
Phase Shift Keying
Modulation mode for which the information lies within the phase or within the phase transitions.
Minimum Shift Keying (MSK)
Demodulation and Algorithms
Phase Shift Keying (PSK)
Quadrature Amplitude Modulation
Modulation mode for which the information is encrypted both in the amplitude and phase.
Quadrature Amplitude Modulation
(QAM)
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Abbreviation
RMS
RX filter
Transmit filter
VSA
Annex
Predefined Standards and Settings
Meaning
Root Mean Square
See section
Averaging RMS Quantities
Receive Filter
Baseband filter in analyzer used for signal-adapted filtering.
System-Theoretical Modulation and Demodulation Filters
Transmitter Filter
Digital impulse shaping filter in signal processing unit of transmitter.
System-Theoretical Modulation and Demodulation Filters
Vector Signal Analysis
Measurement at complex modulated RF carriers.
A.2 Predefined Standards and Settings
In the "Digital Standards" menu, predefined basic settings for standards can be
The most common measurements are predefined as standard settings for a large number of mobile radio networks. The instrument comes prepared with the following settings for those standards:
● Capture length and result length
● Signal description
● Modulation
● Transmit filter and measurement filter
● Burst/Pattern search configuration
● Result range alignment
● Evaluation range settings
● Display configuration
The standard settings are grouped in folders to facilitate selecting a standard.
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Predefined Standards and Settings
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Predefined Standards and Settings
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Predefined Standards and Settings
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Predefined Standards and Settings
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Predefined Standards and Settings
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Predefined Standards and Settings
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Predefined Measurement and Tx Filters
A.3 Predefined Measurement and Tx Filters
The most frequently required measurement and TX filters required for vector signal analysis according to digital standards are provided by the R&S FPS VSA application.
A.3.1 Transmit Filters
The transmit filters required for common standards are predefined in the VSA application.
Table 1-2: Overview of predefined Transmit filters
RC Raised cosine
RRC Root raised cosine
Gauss
GMSK
Linearized GMSK
EDGE Narrow Pulse Shape
EDGE Wide Pulse Shape
Half Sine
APCO25 C4FM
APCO25 H-CPM
APCO25 H-DQPSK
APCO25 H-D8PSK Narrow
APCO25 H-D8PSK Wide
CDMA2000 1X Forward
CDMA2000 1X Reverse
Rectangular
None
USER
Gauss filter
Gauss filter convolved with a rectangular filter; typically used for
MSK
Standard-specific filter for GSM EDGE (3GPP TS 45.004), normal symbol rate
Standard-specific filter for GSM EDGE (higher symbol rate)
Standard-specific filter for GSM EDGE (higher symbol rate)
Half Sine filter
Filter for the APCO25 C4FM standard.
Filter for the APCO25 Phase 2 standard.
Filter for the APCO25 Phase 2 standard.
Filter for the APCO25 Phase 2 standard.
Filter for the APCO25 Phase 2 standard.
Filter for CDMA ONE forward link (TIA/EIA/IS-95-A May 1995) and
CDMA2000 1X forward link ( http://www.3gpp2.org/Public_html/ specs/C.S0002-C_v1.0.pdf
28/05/2002)
Filter for CDMA ONE forward link (TIA/EIA/IS-95-A May 1995) and
CDMA2000 1X reverse link ( http://www.3gpp2.org/Public_html/ specs/C.S0002-C_v1.0.pdf
28/05/2002)
Rectangular filter in the time domain with a length of 1 symbol period
No filter is used.
User-defined filter. Define the filter using the
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Predefined Measurement and Tx Filters
A.3.2 Measurement Filters
The most frequently required measurement filters are predefined in the VSA application.
Table 1-3: Overview of predefined measurement filters
EDGE NSR Measurement filter required for the "EDGE, Normal Symbol
Rate" standard. (see 3GPP TS 45.005, chapter 4.6 Modulation
Accuracy). The resulting system is NOT inter-symbol interference free.
EDGE HSR (Narrow Pulse)
EDGE HSR (Wide Pulse)
Gauss
Low ISI Meas Filter
Low Pass (Narrow)
Low Pass (Wide)
Rectangular
RRC
USER
NONE
Measurement filter required for the "EDGE, High Symbol Rate,
Narrow Pulse" standard.
Measurement filter required for the "EDGE, High Symbol Rate,
Wide Pulse" standard.
Classic Gauss filter with an adjustable BT
Measurement filter implemented to retain a low intersymbol inferference. Best suited for eye diagrams or I/Q vector diagrams. Not necessarily suited for EVM evaluation due to amplification in the pass band.
Pass band up to F symbol
/2
Stop band starts at F symbol
(-40dB)
Pass band up to F symbol
Stop band starts at 1.5*F symbol
(-40dB)
Rectangular filter in the time domain with a length of 1 symbol period; integrate and dump effect
Root Raised Cosine Filter. The roll-off parameter "Alpha" is set according to the Transmit filter if the "Auto (according to Trans-
mit filter)" option is enabled (see "Using the Transmit Filter as a
Measurement Filter (Auto)" on page 186). Otherwise it must be
set manually.
If the Transmit filter is also a Root Raised Cosine filter with the same roll-off parameter, the resulting system is inter-symbol interference free.
User-defined filter.
Define the filter using the
function or the
command.
For details see
chapter 8.2.1, "How to Select User-Defined Filters" , on page 213.
No measurement filter is used.
The frequency response of the available standard-specific measurement filters is
shown in chapter A.6.6.2, "Measurement Filter" , on page 433.
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ASCII File Export Format for VSA Data
A.3.3 Typical Combinations of Tx and Measurement Filters
Typical combinations of Tx and Meas filters are shown in table 1-4
; they can be set in
the VSA application using "Meas filter = AUTO" (see "Using the Transmit Filter as a
Measurement Filter (Auto)" on page 186).
Table 1-4: Typical combinations of Tx and Meas filters
Transmit filter Measurement filter
(analyzer)
Remarks
RC (raised cosine)
RRC (root raised cosine)
GMSK
Linearized GMSK
Gauss
Rectangular
Half Sine
CDMA2000 1X FORWARD
CDMA2000 1X REVERSE
APCO25 C4FM
APCO25 H-CPM
APCO25 H-DQPSK
APCO25 H-D8PSK Narrow
APCO25 H-D8PSK Wide
EDGE Narrow Pulse Shape
EDGE Wide Pulse Shape
User
-
-
RRC
EDGE NSR filter combination without intersymbol interference (ISI) filter combination without ISI filter combination with low ISI standard specific filter; filter combination with
ISI
-
-
-
Low ISI Meas Filter
Low ISI Meas Filter
Rectangular
Rectangular
Low ISI Meas Filter
Low ISI Meas Filter
Low ISI Meas Filter filter combination with low ISI filter combination without ISI filter combination without ISI filter combination without ISI filter combination without ISI filter combination without ISI filter combination without ISI filter combination without ISI filter combination without ISI filter combination without ISI
EDGE HSR (Narrow
Pulse) standard specific filter; filter combination with
ISI
EDGE HSR (Wide Pulse) standard specific filter; filter combination with
ISI
Low ISI Meas Filter filter combination with low ISI
A.4 ASCII File Export Format for VSA Data
The data of the file header consist of three columns, each separated by a semicolon: parameter name; numeric value; basic unit. The data section starts with the keyword
"Trace <n>" (<n> = number of stored trace), followed by the measured data in one or several columns (depending on the result type) which are also separated by a semicolon.
If several traces in several windows are exported to one file, the data for each window is listed subsequently. Within the data for a single window, the data for the individual traces is listed subsequently.
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ASCII File Export Format for VSA Data
For details on which data is stored for which result display, see TRACe<n>[:DATA] on page 374.
Table 1-5: ASCII file format for VSA trace data export
File contents Description
Header
Type;FPS;
Version;1.40;
Date;01.Apr 2012;
Header section for individual window
Screen;1;
Points per Symbol;4; x Axis Start;-13;sym; x Axis Stop;135;sym; y per div;0.22000000000000003;
Ref value y axis;-10.00;dBm;
Ref value position;100;%;
Start of ResultRange in Capture Buffer;
6400;sym
Header section for individual trace
Trace; 1;
Meas Result;IQ;
Meas Signal;Meas;
Demodulator;Offset QPSK;
ResultMode;Trace; x unit;sym; y unit;dBm;
Trace Mode;Clear Write;
Values;800;
Data section for individual trace
10000;-10.3;-15.7
10130;-11.5;-16.9
10360;-12.0;-17.4
...;...;
Header section for individual trace
Trace; 2;
Meas Result;IQ;
Instrument model
Firmware version
Date of data set storage
Window name
Points per symbol
Start value of the x axis
Stop value of the x axis
Y axis range per division
Y axis reference value
Y axis reference position
Number of symbol at which exported capture buffer range begins
First trace
Result type
Data source (measurement or reference data)
Demodulation type
Result mode
Unit of the x axis
Unit of the y axis
Trace mode
Number of measurement points
Measured values: <x value>, <y1>, <y2>;
<y2> is only available with detector AUTOPEAK and contains the smallest of the two measured values for a measurement point
Next trace in same window
Result type
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Known Data File Syntax Description
File contents
Meas Signal;Meas;
Demodulator;Offset QPSK;
ResultMode;Trace; x unit;sym; y unit;dBm;
Trace Mode;Clear Write;
Values;800;
Data section for individual trace
...
Header section for individual window
Screen;2;
...
Header section for individual trace
Trace; 1;
Data section for individual trace
...
Description
Data source (measurement or reference data)
Demodulation type
Result mode
Unit of the x axis
Unit of the y axis
Trace mode
Number of measurement points
Name of next window
First trace in second window
A.5 Known Data File Syntax Description
When you load a Known Data file, the R&S FPS-K70 application checks whether the file complies with the following syntax:
Table 1-6: Known Data File Syntax
Syntax Possible Values Description as specified File Header <RS_VSA_KNOWN_DATA_FILE
Version="01.00">
<Comment></Comment>
<Base></Base> arbitrary
2 | 16
<ModulationOrder></Modulation-
Order>
2 | 4 | 8 | 16 | 32 | 64 | 128 |
256
Optional file description
The base used to specify the <Data> values (binary or hexadecimal)
For <ModulationOrder> values ≥32, use binary (2).
Number of values each symbol can represent (order of modulation), e.g. 8 for 8-PSK
For <ModulationOrder> values ≥32, use <Base> = 2.
*) the exact number also depends on available memory space
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Known Data File Syntax Description
Syntax
<ResultLength></ResultLength>
Possible Values
1 ... up to 2000 *)
<Data></Data> One character per symbol in the sequence
Possible characters are:
0 to n-1, where n is the
<ModulationOrder>
Spaces, tabs and line breaks are ignored
</RS_VSA_KNOWN_DATA_FILE> as specified
*) the exact number also depends on available memory space
Description
Number of symbols in each <Data> element
The number must be identical to the "Result Length" setting in the "Result Range" dialog box, i.e. the number of symbols to be demodulated.
One possible sequence of symbols that can be demodulated from the input signal
Up to 6000 *) different sequences, i.e. <Data>-elements, can be defined in total
File End
Sample xml file for known data
<RS_VSA_KNOWN_DATA_FILE Version="01.00">
<Comment> Standard EDGE_8PSK </Comment>
<Base> 16 </Base>
<ModulationOrder> 8 </ModulationOrder>
<ResultLength> 148 </ResultLength>
<Data> 777 511 727 242 206 341 366 632 073 607
770 173 705 631 011 235 507 476 330 522
177 177 171 117 777 177 717 717 111 615
527 046 104 004 106 047 125 415 723 344
241 264 773 111 337 446 514 600 677 7 </Data>
<Data> 77 511 727 242 206 341 366 632 073 607
770 173 705 631 011 235 507 476 330 522
177 177 171 117 777 177 717 717 111 615
527 046 104 004 106 047 125 415 723 344
241 264 773 111 337 446 514 600 677 7 7 </Data>
<Data> 7 511 727 242 206 341 366 632 073 607
770 173 705 631 011 235 507 476 330 522
177 177 171 117 777 177 717 717 111 615
527 046 104 004 106 047 125 415 723 344
241 264 773 111 337 446 514 600 677 7 77 </Data>
<Data> 7 777 511 727 242 206 341 366 632 073 607
770 173 705 631 011 235 507 476 330 522
177 177 171 117 777 177 717 717 111 615
527 046 104 004 106 047 125 415 723 344
241 264 773 111 337 446 514 600 677 </Data>
<Data> 77 777 511 727 242 206 341 366 632 073 607
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Formulae
770 173 705 631 011 235 507 476 330 522
177 177 171 117 777 177 717 717 111 615
527 046 104 004 106 047 125 415 723 344
241 264 773 111 337 446 514 600 67 </Data>
</RS_VSA_KNOWN_DATA_FILE>
A.6 Formulae
A.6.1 Trace-based Evaluations
The trace-based evaluations all take place at the sample rate defined by the "Display
Points Per Symbol" parameter (see
"Display Points/Sym" on page 203). The sampling
instants at this rate are referred to as "t" here, i.e.
t=n*T
D where T
D
equals the duration of one sampling period at the sample rate defined by the
"Display Points Per Symbol" parameter.
Test parameter
Error vector
Magnitude
Phase
Formula
EV
MEAS
REF
Error Vector Magnitude (EVM)
EVM
EV
C with the normalization contant C depends on your setting. By default C² is the mean power of the reference signal.
C
1
K
k
REF 2
T duration of symbol periods
Mag
MEAS
MEAS
Mag
REF
REF
Phase
MEAS
Phase
REF
MEAS
REF
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Formulae
Test parameter
Frequency
Magnitude error
Phase error
Frequency error
Formula
FREQ
MEAS
2
1
d dt
MEAS
FREQ
REF
2
1
d dt
REF
MAG _ ERR MAG
MEAS
MAG
REF
PHASE _ ERR PHASE
MEAS
PHASE
REF
FREQ _ ERR
FREQ
MEAS
FREQ
REF
FSK Modulation
The trace based results for FSK signals are the same as those available for linear modulation types. However, as the signal processing for FSK signals is performed on the magnitude and instantaneous frequency, the I/Q based results first require a recon-
The dashed outline of the "compensate" blocks indicate that these operations are optionally (de-)activated depending on the corresponding user settings. With respect to
FSK measurements, the optional compensation parameters are:
● FSK Reference deviation
● Carrier frequency drift
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Formulae f
REF
(n )
Figure 3
Compensate:
Ref. deviation
Reference
Frequency
Compensate:
Ref. deviation
Frequency
Modulator
Reference
I/Q f
MEAS
(n )
Compensate:
Timing
Carrier offset
Compensate:
Carrier drift
Measured
Frequency
Frequency
Modulator
X
Measured
I/Q
A
MEAS
(n )
Compensate:
Timing
Gain
Fig. 1-1: Reconstruction of the reference and measured I/Q waveforms for FSK modulation
Note that a reference deviation error is corrected in the reference frequency trace. This ensures that the frequency deviation in the measured frequency trace corresponds to that of the originally measured signal. With respect to the I/Q reconstruction, the measured magnitude is timing compensated using the timing offset estimated from the measured instantaneous frequency. This ensures that the measured magnitude and frequency remain synchronized in the reconstructed I/Q waveform.
A.6.2 Result Summary Evaluations
The evaluations for the result summary take place at the sample rate defined by the
"Display Points Per Symbol" parameter (see
"Display Points/Sym" on page 203). This
value can be one of the following:
● "1": only the symbol instant contributes to the result
● "2": two samples per symbol instant contribute to the result (required for offset
QPSK)
● the "Sample rate" defined for data acquisition (see "Sample Rate" on page 156): all
samples contribute to the result equally
The results are determined by the evaluation range.
The sampling instants at this rate are referred to as "t" here, i.e.
t=n*T
D where T
D
equals the duration of one sampling period at the sample rate defined by the
"Display Points Per Symbol" parameter
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Formulae
A.6.2.1
PSK, QAM and MSK Modulation
For PSK, QAM and MSK modulation the estimation model is described in detail in
chapter chapter 4.5.1, "PSK, QAM and MSK Modulation" , on page 100. The parame-
ters of the PSK, QAM and MSK-specific result summary table can be related to the distortion model parameters as follows:
Table 1-7: Evaluation of results in the PSK, QAM and MSK result summary
EVM RMS
1
N
n
EVM
n T
D
2
Peak max
EVM
n T
D
Modulation error
RMS
Peak
20 log
10
1
N
n
EV
n T
D
2
1
K
k
REF k T
2
min
MER
n T
D
with MER
n T
D
20 log
10
1
N
n
EV
n T
D
2
1
K
k
REF k T
2
Magnitude error
RMS
Peak
1
N
n
MAG _ ERR
n T
D
2 max
MAG _ ERR
n T
D
Phase error RMS
Peak
1
N
n
PHASE _ ERR
n T
D
2 max
PHASE _ ERR
n T
D
RHO (correlation coefficient)
n
n
REF
REF
*
MEAS
2
n
MEAS
2
2
KKF
AKF
MEAS
REF
, REF
AKF
2
MEAS
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Formulae
IQ Offset C
IQ Imbalance
B
Gain Imbalance G
Quadrature
Error Ɵ
Amplitude
Droop A
C
C
2 c
Q
2 c
I g
I
g
Q
10
1
K
k
REF 2 log
10
B
B
g
I g
I
g
Q g
Q
e j
e j
20 log
10
G
G g
Q
20 g i log
10
180
A
A e
T
20 log
10
dB Sym
A.6.2.2
FSK Modulation
For FSK modulation the estimation model is described in detail in section
chapter 4.5.2, "FSK Modulation" , on page 110. The parameters of the FSK-specific result
summary table can be related to the distortion model parameters as follows:
Table 1-8: Evaluation of results in the FSK result summary
Frequency Error RMS
1
N
n
FREQ _ ERR
n T
D
2
Peak max
FREQ _ ERR
n T
D
Magnitude Error RMS
Peak
1
N
n
MAG _ ERR
n T
D
2 max
MAG _ ERR
n T
D
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Formulae
FSK Deviation Error
ERR
FSK Measurement Deviation
MEAS
FSK Reference Deviation
REF
Carrier Frequency Error f
0
Carrier Frequency Drift f d
ERR
MEAS
REF
( B 1 )
REF
Estimated FSK deviation error [Hz].
MEAS
B
REF
Estimated FSK deviation of the meas signal [Hz].
FSK reference deviation as entered by the user [Hz].
f
0
C
2
The carrier frequency error of the measured signal [Hz].
f d
D
2 T
The drift in the carrier frequency of the measured signal
[Hz/Sym].
A.6.3 Statistical Evaluations for the Result Summary
The statistical evaluations in the result summary are based on the measurement results that are displayed in the "Current" column. Hence, the index "m" here represents the current evaluation, "M" is the total number of evaluations. In single sweep mode, M coresponds to the statistics count.
If the measurement values are represented in the logarithmic domain, the linear values are averaged. The result is then subsequently converted back into logarithmic domain.
The linear values are indicated by the subscript [lin] in chapter A.6.2.1, "PSK, QAM and
MSK Modulation" , on page 428.
Mean
xˆ
M
Mathematical expression x
M
1
M
m x m
Calculation in R&S FPS x
M
M 1
x
M
M
1
x
M with x
0
0
Peak
xˆ
M
ˆ
M
x idx with idx arg max m x m
M
M
x
M if x
M
x
M 1 if x
M
M 1
M 1 with x
0
0
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R&S ® FPS-K70
StdDev σ
M
95%ile x
95 , M
Mathematical expression
M
1
M
m
x m
x m
2 with x
M
1
M
m x m x
95 , M
x Pr
x m
x
0 .
95
Pr() denotes the probability
Annex
Formulae
Calculation in R&S FPS
M
M 1
2
M 1
M
x
M
x
M
2 with
0
0
Sorting the values and giving the 95%ile.
A.6.4 Trace Averaging
The index "m" represents the current evaluation, "M" is the total number of evaluations.
In single sweep mode, M coresponds to the statistics count. The index "s" represents the s th sample within the trace.
If the measurement results are represented in logarithmic domain, the average operation is performed on the linear values. The result is then subsequently converted back into logarithmic domain.
RMS Average x s , M
Linear Average x s , M
Measurements
● Error Vector Magnitude (EVM)
● Meas/Ref magnitude
● Capture Buffer magnitude
All measurements where trace averaging is possible except for the measurements listed for RMS averaging
Calculation in R&S FPS x s , M
M 1
x s
2
, M 1
M
x
2 s , M x s , M
M 1
x s , M 1
M
x s , M
A.6.5 Analytically Calculated Filters
The following filters are calculated during runtime of the unit and as a function of the operating parameter Alpha or BT.
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Filter Type Setting Parameter Impulse Response
Raised cosine (RC) Alpha ( ⍺) h
sin
t
t
T
T
1 cos
4
t
T
T t
2
Root raised cosine
(RRC)
Alpha ( ⍺) h
4 cos
1
t
T
T
1
sin
1
4 t
4 t T
2
T
t T
Gaussian filter
(Gauss) ETSI TS
100 959 (V8.3.0)
BT h
exp
2
t
2
2 T
T
2 with
ln 2
2 BT
A.6.6 Standard-Specific Filters
A.6.6.1
Transmit filter
EDGE Tx filter ETSI TS 300 959 (V8.1.2) (Linearized GMSK) c
0
3
i
0
0
S
t iT
for else
0 t 5T
S
sin
sin
0
2
0
t
g
t
dt
0
4 T g
'
( t ' ) dt '
for for else
0 t 4 T
4 T t 8 T g
1
2 T
Q 2 0 .
3 t
T
5 T 2 ln
Q 2 0 .
3 t
T
3 T ln
2
Annex
Formulae
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Formulae
Q
1
2
t
e
2
2 d c
0
(t) is the impulse response of the EDGE transmit filter
A.6.6.2
Measurement Filter
EDGE Measurement filters
RC filter, Alpha = 0.25, single-side-band 6 dB bandwith = 90 kHz Windowing by multiplying the impulse response according to the following equation: w
1 ,
0
0 ,
.
5
1 cos
t 1 .
5 T
2 .
25 T
,
0
1 .
5 T t
1 .
5 T t 3 .
75 T t 3 .
75 T
The following figure shows the frequency response of the standard-specific measurement filters.
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Formulae
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Formulae
Low-ISI Filters
The following frequency responses are obtained when using a low-ISI measurment filter and the Transmit filter indicated in the title of each diagram.
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Formulae
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Formulae
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Formulae
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I/Q Data File Format (iq-tar)
A.7 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 preview the I/Q data in a web browser, and allows you to include user-specific data.
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.
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I/Q Data File Format (iq-tar)
Sample iq-tar files
Some sample iq-tar files are provided in the C:/R_S/Instr/user/vsa/
DemoSignals directory on the R&S FPS.
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
Contains a stylesheet to display the I/Q parameter XML file and a preview of the
I/Q data in a web browser.
A sample stylesheet is available at http://www.rohde-schwarz.com/file/ open_IqTar_xml_file_in_web_browser.xslt
.
A.7.1 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.
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>FSV-K10</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>
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I/Q Data File Format (iq-tar)
<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>
Element
RS_IQ_TAR_File-
Format
Name
Comment
DateTime
Samples
Clock
Format
DataType
Description
The root element of the XML file. It must contain the attribute fileFormatVersion that contains the number of the file format definition. Currently, fileFormatVersion "2" is used.
Optional: describes the device or application that created the file.
Optional: contains text that further describes the contents of the file.
Contains the date and time of the creation of the file. Its type is xs:dateTime (see
RsIqTar.xsd).
Contains the number of samples of the I/Q 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.
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".
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
Specifies the binary format used for samples in the I/Q data binary file (see
DataFilename element and chapter A.7.2, "I/Q Data Binary File" , on page 443).
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)
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I/Q Data File Format (iq-tar)
Element
ScalingFactor
NumberOfChannels
DataFilename
UserData
PreviewData
Description
Optional: describes how the binary data 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.
Optional: specifies the number of channels, 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
assumed.
Contains the filename of the I/Q data binary file that is part of the iq-tar file.
It is recommended that the filename 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)
Examples:
● xyz.complex.1ch.float32
● xyz.polar.1ch.float64
● xyz.real.1ch.int16
● xyz.complex.16ch.int8
Optional: contains user, application or 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.
Optional: contains further XML elements 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.
Example: ScalingFactor
Data stored as int16 and a desired full scale voltage of 1 V
ScalingFactor = 1 V / maximum int16 value = 1 V / 2 15 = 3.0517578125e-5 V
Scaling Factor Numerical value
Minimum (negative) int16 value
Maximum (positive) int16 value
- 2 15 = - 32768
2 15 -1= 32767
Numerical value x ScalingFactor
-1 V
0.999969482421875 V
Example: PreviewData in XML
<PreviewData>
<ArrayOfChannel length="1">
<Channel>
<PowerVsTime>
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I/Q Data File Format (iq-tar)
<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>
</ArrayOfChannel>
</PreviewData>
A.7.2 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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I/Q Data File Format (iq-tar) 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
...
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)
Annex
I/Q Data File Format (iq-tar)
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R&S ® FPS-K70 Index
Index
Symbols
4ASK
Constellation diagram ................................................. 85
8PSK
Constellation diagram ................................................. 70
16APSK
Constellation diagram ................................................. 86
95%ile
Formula .....................................................................430
A
Aborting
Sweep ............................................................... 161, 162
AC/DC coupling .......................................................143, 149
Activating
VSA (remote) ............................................................ 269
Alignment
Result range ............................................................. 175
Alpha/BT ................................................................. 138, 186
Amplitude
Configuration ............................................................ 147
Configuration (remote) .............................................. 293
Distortion, effect ........................................................ 108
Settings ..................................................................... 147
Amplitude droop
Compensation ...........................................................178
Definition ................................................................... 107
Formula .....................................................................428
Analysis
Bandwidth, definition ...................................................64
Button ....................................................................... 190
Analysis interval
Configuration (MSRA, remote) ................................. 354
MSRA ............................................................... 156, 301
Analysis line .................................................................... 125
Configuration (MSRA, remote) ................................. 354
Analyzing
Measured data .......................................................... 221
APSK
Modulation type ........................................................ 135
Symbol mapping ......................................................... 86
ASCII Trace export ..........................................................421
ASK
Modulation type ........................................................ 135
Symbol mapping ......................................................... 85
Attenuation ...................................................................... 149
Auto .......................................................................... 149
Configuration (remote) .............................................. 294
Electronic .................................................................. 150
Manual ...................................................................... 149
Option ....................................................................... 150
Protective (remote) ................................................... 288
Audio signals
Output (remote) ................................................ 144, 289
Auto level
Hysteresis ................................................................. 189
Reference level ................................................. 148, 188
Softkey .............................................................. 148, 188
Auto settings
Meastime Auto .......................................................... 189
Meastime Manual ..................................................... 189
Automatic
Configuration ............................................................ 188
Configuration (remote) .............................................. 329
Averaging
Measurements .......................................... 165, 168, 171
B
Bandwidth
Coverage, MSRA mode ............................................ 124
Demodulation ..............................................................58
Extension options ................................................. 64, 65
Maximum usable .........................................................64
Relationship to sample rate ........................................ 65
Signal processing ....................................................... 56
Usable (max.) ............................................................. 64
Bit error rate (BER)
Result type .................................................................. 20
Burst GSM EDGE
Measurement example ............................................. 235
Burst search
Algorithm .....................................................................92
Auto configuration ..................................................... 166
Configuration ............................................................ 164
Demodulation process ................................................ 89
Enabling .................................................................... 165
Errors ........................................................................ 246
Gap length ................................................................ 166
Parameters ................................................................. 90
Process ....................................................................... 90
Remote ..................................................................... 308
Robustness ................................................................. 91
Tolerance .................................................................. 166
Burst signal ..................................................................... 139
Bursts
Display ........................................................................ 12
Length (min/max) ...................................................... 140
Programming example ..............................................405
Reference for result range ........................................ 174
Run-in ....................................................................... 140
Signal structure ......................................................... 140
Useful length ............................................................. 119
C
Capture buffer
Data source ................................................................ 15
Display ...................................................................... 122
Length ....................................................................... 116
Navigating ................................................................. 233
Reference for result range ........................................ 174
Result types ................................................................ 15
Capture Buffer
Display ...................................................................... 121
Capture length
Data acquisition ........................................................ 156
Display ........................................................................ 12
Capture offset
MSRA applications ................................................... 161
Remote ..................................................................... 355
Softkey ...................................................................... 161
Capture oversampling
see Sample rate ..........................................................63
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Capture ranges ............................................................... 122
Carrier frequency drift
Compensation ...........................................................179
Definition ................................................................... 115
Formula .....................................................................429
Carrier frequency error
Formula .....................................................................429
Center frequency .............................................................146
Softkey ...................................................................... 146
Step size ................................................................... 146
Channel bandwidth
MSRA mode ............................................................. 124
Channel Frequency Response Group Delay
Result type .................................................................. 22
Channel Frequency Response Magnitude
Result type .................................................................. 22
Closing
Channels (remote) .................................................... 271
Windows (remote) .............................................361, 364
Coarse Synchronization .................................................. 183
Compatible
Patterns .................................................................... 170
Compensation
Demodulation ....................................................176, 178
Modulation errors ...................................................... 102
Remote ..................................................................... 318
Constellation
Frequency (result type) ............................................... 23
Constellation I/Q
Result type .................................................................. 24
Rotated, Result type ................................................... 25
Constellation points
Symbol mapping ......................................................... 67
Continue single sweep
Softkey ...................................................................... 162
Continuous signal ............................................................139
Continuous sweep
Softkey ...................................................................... 161
Conventions
SCPI commands ....................................................... 265
Copying
Measurement channel (remote) ................................270
Couple Windows
Markers ..................................................................... 196
Coupling
Input (remote) ........................................................... 288
Customized
Measurement, performing .........................................212
D
Data acquisition
Capture length .......................................................... 156
Configuration ............................................................ 155
MSRA ............................................................... 156, 301
Sample rate .............................................................. 156
Usable I/Q Bandwidth ............................................... 156
Data source
Capture buffer ............................................................. 15
Display ........................................................................ 13
Equalizer ..................................................................... 17
Error vector ................................................................. 16
Evaluation method ...................................................... 14
Meas & Ref ................................................................. 15
Modulation accuracy ................................................... 17
Modulation errors ........................................................ 16
Result types ................................................................ 18
Symbols ...................................................................... 16
Decimal separator
Trace export ..............................................................194
Default values
Preset ....................................................................... 128
Scaling ...................................................................... 153
Deleting
Settings files ............................................................. 131
Standards ................................................................. 131
Delta markers
Defining .....................................................................196
Demodulation
Advanced .................................................................. 180
Bandwidth ................................................................... 58
Compensation ...................................................176, 178
Configuration ............................................................ 175
Estimation points per symbol .................................... 182
Known data ............................................................... 124
Normalization ............................................................ 181
Offset EVM ............................................................... 184
Process ....................................................................... 88
Remote ..................................................................... 318
Synchronization ................................................ 180, 183
Diagram footer information ................................................13
Differential PSK (DPSK)
Symbol mapping ......................................................... 73
Digital standards
Assigned patterns ..................................................... 169
Assigning patterns .................................................... 170
Configuration ............................................................ 129
Performing measurement according to ..................... 210
Predefined ................................................................ 412
Remote ..................................................................... 273
Removing assigned patterns .................................... 170
Selecting ................................................................... 130
Softkey ...................................................................... 130
VSA measurements .................................................. 129
Display
Configuration ............................................................ 201
Information .................................................................. 11
Points per symbol ............................. 121, 203, 425, 427
Drop-out time
Trigger ...................................................................... 161
Duplicating
Measurement channel (remote) ................................270
E
EDGE
Filters, frequency response ...................................... 433
Measurement example ............................................. 235
Electronic input attenuation ..................................... 149, 150
Equalizer
Basics ......................................................................... 97
Data source ................................................................ 17
Loading ..................................................................... 180
MSRA mode ............................................................. 125
Result types ................................................................ 17
Storing ...................................................................... 180
Error log .......................................................................... 262
Error messages
Explanation ............................................................... 246
Error model
FSK ........................................................................... 112
PSK, QAM, MSK .......................................................100
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Error vector
Data source ................................................................ 16
Definition ................................................................... 102
Formula .....................................................................425
Result types ................................................................ 16
Error Vector Magnitude (EVM)
Definition ................................................................... 102
Formula .....................................................................425
Result type .................................................................. 26
RMS, peak (formulae) ...............................................428
Errors
IF OVLD .................................................................... 148
Estimation
Algorithms ................................................................. 100
FSK ........................................................................... 113
Points per symbol ..................................... 101, 121, 182
PSK, QAM, MSK .......................................................101
Ranges ..................................................................... 101
Evaluation
Refreshing ................................................................ 162
Specific range ........................................................... 163
Traces ....................................................................... 192
Evaluation methods
Data source ................................................................ 14
Remote ..................................................................... 359
Evaluation range
Configuration ............................................................ 187
Configuration (remote) .............................................. 328
Definition ................................................................... 119
Display ...................................................................... 120
Entire result range .................................................... 188
Start/stop values ....................................................... 188
Export format ...................................................................421
Exporting
I/Q data ............................. 127, 206, 207, 208, 439, 443
I/Q data (remote) ...................................................... 390
Softkey ...................................................................... 207
Trace data .................................................................226
Traces ....................................................................... 207
External trigger ................................................................ 159
Level (remote) ...........................................................305
Eye diagram
Frequency (result type) ............................................... 27
Imag (Q) (result type) ..................................................28
Real (I) (result type) .................................................... 29
F
Factory settings
Restoring .................................................................. 129
File name
Settings ..................................................................... 130
Files
Format, I/Q data ........................................................439
I/Q data binary XML .................................................. 443
I/Q parameter XML ................................................... 440
Filter bandwidth (BT)
Measurement filter .................................................... 186
Transmit filter ............................................................ 138
Filters
(De-)Modulation .......................................................... 58
Customized ................................................................. 61
Customized, creating ................................................. 61
Customized, selecting ...............................................213
Formulae ...................................................................431
Measurement ................................................ 58, 59, 420
Measurement (formulae) .......................................... 433
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Predefined ................................................................ 419
Receive ....................................................................... 58
Reference ................................................................... 58
Signal processing ....................................................... 56
Standard-specific (formulae) .....................................432
Transmit .............................................................. 58, 419
Transmit (formulae) .................................................. 432
Typcial combinations ................................................ 421
FILTWIZ ............................................................................ 61
Fine Synchronization .......................................................183
Folders
Digital standards ....................................................... 130
Formulae
Analytically calculated filters ..................................... 431
Evaluation ................................................................. 425
Measurement filters .................................................. 433
Parameters ............................................................... 425
Result Summary parameters .................................... 428
Result Summary parameters (FSK) .......................... 429
Standard-specific filters ............................................ 432
Statistics ................................................................... 430
Trace averaging ........................................................ 431
Transmit filters .......................................................... 432
Free Run
Trigger ...................................................................... 159
Frequency
Absolute (result type) .................................................. 29
Configuration ............................................................ 146
Configuration (remote) .............................................. 291
Formula .....................................................................425
Offset ........................................................................ 147
Relative (result type) ................................................... 31
Frequency error
Absolute (result type) .................................................. 32
Formula .....................................................................425
Relative (result type) ................................................... 33
RMS, peak (formulae) ...............................................429
Frequency response
Channel (result type) .................................................. 22
EDGE filters .............................................................. 433
Low-ISI filters ............................................................ 435
Magnitude (result type) ............................................... 35
Phase (result type) ......................................................36
Frequency Response Group Delay
Channel (result type) .................................................. 22
Result type .................................................................. 34
Frequency shift keying (FSK)
Symbol mapping ......................................................... 77
Frontend
Configuration ............................................................ 142
FSK
Configuration (remote) .............................................. 287
Calculating errors ......................................................426
Compensation ...........................................................426
Deviation error (formula) ........................................... 429
Error model ............................................................... 112
Estimation ................................................................. 113
Measurement deviation (formula) ............................. 429
Modulation type ........................................................ 135
Reference deviation .................................................. 137
Signal model ............................................................. 110
FSK deviation error
Compensation ...........................................................179
Definition ................................................................... 115
FSK reference deviation
Formula .....................................................................429
458
R&S ® FPS-K70 Index
G
Gain distortion
Effect .........................................................................108
Gain imbalance
Definition ................................................................... 105
Effect .........................................................................105
Formula .....................................................................428
Preconditions for measurement ................................ 106
Gating ..............................................................................233
GSM
Programming example ..............................................405
H
I
Hardware settings
Displayed .................................................................... 12
Hysteresis
Lower (Auto level) ..................................................... 189
Trigger ...................................................................... 160
Upper (Auto level) ..................................................... 189
I/Q bandwidth
Usable .................................................................57, 156
I/Q correlation threshold
Pattern search .......................................................... 167
I/Q data
Export file binary data description .............................443
Export file parameter description .............................. 440
Exporting ...........................................................127, 207
Exporting (remote) .................................................... 390
Exporting/Importing ...................................................208
Importing ........................................................... 127, 207
Importing (remote) .................................................... 390
Importing/Exporting ...................................................206
Maximum bandwidth ................................................... 64
Sample rate ................................................................ 64
I/Q imbalance
Compensation ...........................................................178
Definition ................................................................... 106
Formula .....................................................................428
I/Q offset
(Origin Offset) Definition ........................................... 104
Compensating ...........................................................104
Compensation ...........................................................178
Formula .....................................................................428
I/Q pattern search
see Pattern search ......................................................92
I/Q Power
Trigger ...................................................................... 160
Trigger level (remote) ............................................... 305
IF frequency
Output ....................................................................... 144
Output (remote) ........................................................ 289
IF output .......................................................................... 144
Remote ..................................................................... 289
IF Power
Trigger ...................................................................... 159
Trigger level (remote) ............................................... 305
Importing
I/Q data ..................................... 127, 206, 207, 208, 440
I/Q data (remote) ...................................................... 390
Softkey ...................................................................... 207
Impulse response
Magnitude (result type) ............................................... 37
Phase (result type) ......................................................38
Real/Imag (result type) ............................................... 38
Input
Configuration ............................................................ 142
Configuration (remote) .............................................. 287
Coupling ............................................................143, 149
Coupling (remote) ..................................................... 288
Overload (remote) .....................................................288
RF ............................................................................. 143
Settings ............................................................. 142, 149
Source Configuration ................................................ 142
Source Configuration (Softkey) .................................142
Input sample rate (ISR)
Definition ..................................................................... 64
Input sources
Radio frequency ........................................................143
Input/Frontend
Softkey ...................................................................... 142
Installation ......................................................................... 10
Intersymbol interference (ISI) ............................................ 58
Filter ............................................................................ 58
ISI-free system .................................................................. 59
K
Keys
BW (not used) ........................................................... 127
MKR -> ......................................................................198
MKR FUNCT (not used) ........................................... 127
Peak Search ............................................................. 198
RUN CONT ............................................................... 161
RUN SINGLE ............................................................ 162
SPAN (not used) ....................................................... 127
Known data ..................................................................... 141
Creating files ............................................................. 219
Dependencies, restrictions ....................................... 123
Enabling .................................................................... 142
File syntax .................................................................423
Files .......................................................................... 218
Fine synchronization ......................................... 183, 184
Loading ..................................................................... 142
Recording tool ...........................................................219
Symbol decisions ........................................................ 94
Working with ............................................................. 218
L
Limit lines
Current/mean/peak values ........................................200
Default ...................................................................... 200
Enabling .................................................................... 200
Modulation accuracy ................................................. 199
Peak search .............................................................. 197
Values ....................................................................... 200
Values, checking .......................................................201
Limits
Configuring ............................................................... 225
Defining (remote) ...................................................... 350
Modulation Accuracy ................................................ 225
Retrieving check results (remote) ............................. 388
Linear average
Formula .....................................................................431
Lines
Limit checking ........................................................... 199
User Manual 1176.8516.02 ─ 06 459
R&S ® FPS-K70 Index
Loading
Settings files ............................................................. 131
Low-ISI filters
Frequency response ................................................. 435
Lower Level Hysteresis ................................................... 189
M
Magnitude
Formula .....................................................................425
Magnitude absolute
Result type .................................................................. 39
Magnitude Absolute
Result type .......................................................... 39, 122
Magnitude error
Definition ................................................................... 103
Formula .....................................................................425
Result type ............................................................ 42, 43
RMS, peak (formulae) .......................................428, 429
Magnitude Overview Absolute
Result type .......................................................... 40, 122
Magnitude Relative
Result type .................................................................. 42
Mapping
see Symbol mapping .................................................. 67
Mapping wizard (mapwiz) ................................................. 87
Marker to Trace ............................................................... 196
Markers
Absolute peak ........................................................... 198
Assigned trace .......................................................... 196
Configuring ............................................................... 194
Coupling ....................................................................196
Deactivating .............................................................. 196
Delta markers ........................................................... 196
General settings (remote) ......................................... 344
Minimum ................................................................... 198
Next minimum ........................................................... 198
Next peak ..................................................................198
Peak ..........................................................................198
Positioning ................................................................ 198
Querying position (remote) ....................................... 372
Retrieving values (remote) ........................................371
Search settings ......................................................... 196
Settings (remote) ...................................................... 340
State ......................................................................... 195
Type .......................................................................... 196
X-value ......................................................................195
Matched filter .....................................................................58
Max Peak ........................................................................ 198
Maximizing
Windows (remote) .....................................................358
Mean
Formula .....................................................................430
Meas & Ref
Data source ................................................................ 15
Result types ................................................................ 15
MEAS filter ........................................................................ 58
Meas only if burst was found ...........................................165
Measurement bandwidth ................................................... 58
Measurement channel
Creating (remote) ......................................................270
Deleting (remote) ...................................................... 271
Duplicating (remote) ................................................. 270
Querying (remote) .....................................................271
Renaming (remote) ................................................... 272
Replacing (remote) ................................................... 270
User Manual 1176.8516.02 ─ 06
Measurement example
Burst GSM EDGE Signals ........................................ 235
Continuous QPSK ....................................................228
Measurement examples
Burst GSM EDGE signal (remote) ............................ 405
Continuous QPSK signal (remote) ............................404
Measurement filter ............................................................ 59
Alpha/BT ................................................................... 186
Configuration ............................................................ 185
Configuration (remote) .............................................. 326
Demodulation process ................................................ 90
Enabling .................................................................... 186
Loading ..................................................................... 186
Predefined ........................................................ 186, 420
Type .......................................................................... 186
User-defined ............................................................. 186
Measurement ranges
Comparison .............................................................. 116
Definition ................................................................... 116
Measurement signal
Evaluating ................................................................. 192
Measurement time
Auto settings ............................................................. 189
Min Gap Length
Bursts ........................................................................166
Min/max values
Y-axis ........................................................................ 152
Minimum ..........................................................................198
Marker positioning .................................................... 198
Next .......................................................................... 198
Minimum shift keying (MSK)
Symbol mapping ......................................................... 79
MKR ->
Key ............................................................................198
ModAcc Limits ................................................................. 200
Modulation
Configuration ............................................................ 134
Display ........................................................................ 12
Errors, FSK ............................................................... 114
Inverted (I/Q, remote) ............................................... 302
Inverted (I/Q) .............................................................157
Mapping .................................................................... 137
Order .........................................................................136
Remote ..................................................................... 276
Symbol Rate ............................................................. 137
Type .......................................................................... 135
User-defined ............................................................... 87
Modulation accuracy
Data source ................................................................ 17
Individual results ......................................................... 50
Limit checking ........................................................... 199
Limit checking, enabling ........................................... 200
Limit lines (remote) ................................................... 349
Limits ........................................................................ 225
Result types ................................................................ 17
Modulation Error Ratio (MER)
Definition ................................................................... 103
Modulation errors .................................................... 100, 102
Data source ................................................................ 16
Formula .....................................................................428
PSK, QAM, MSK .......................................................100
Result types ................................................................ 16
Modulation order
Known data ............................................................... 123
Pattern symbols ........................................................ 173
Modulation type
FSK ........................................................................... 110
460
R&S ® FPS-K70 Index
MSK
Error model ............................................................... 100
Modulation type ........................................................ 135
MSRA
Analysis interval ................................................ 156, 301
Operating mode ........................................................ 124
Trigger .............................................................. 158, 303
MSRA applications
Capture offset ........................................................... 161
Capture offset (remote) .............................................355
Multiple
Measurement channels .............................................. 11
Multiple zoom .................................................................. 205
N
Next Minimum ................................................................. 198
Marker positioning .................................................... 198
Next Peak ........................................................................198
Marker positioning .................................................... 198
Noise
Effect .........................................................................110
Normalization
Demodulation ...........................................................181
O
Offset
Analysis interval ........................................................ 161
EVM .......................................................................... 184
Frequency ................................................................. 147
Pattern ...................................................................... 141
QPSK .......................................................................... 75
QPSK, symbol mapping ..............................................75
Reference level ......................................................... 148
Result range ............................................................. 175
On Off Keying (OOK)
Constellation diagram ................................................. 85
OOK
Symbol mapping ......................................................... 85
Optimization
Demodulation ............................................................182
Options
Bandwidth extension .............................................64, 65
Electronic attenuation ............................................... 150
Preamplifier (B24) ............................................. 143, 149
OQPSK
Constellation diagram ................................................. 76
Output
Audio .........................................................................289
Configuration ............................................................ 142
Configuration (softkey) ..............................................144
IF source (remote) .................................................... 289
Sample rate, definition ................................................ 64
Settings ..................................................................... 144
Trigger ...................................................................... 144
Video .................................................................144, 289
Overload
RF input (remote) ......................................................288
Oversampling
Statistics ................................................................... 203
Overview
Configuration ............................................................ 132
P
Parameters
Description ............................................................ 54, 55
FSK ............................................................................. 55
PSK, QAM, MSK .........................................................54
Retrieving results (remote) ....................................... 377
SCPI parameters .................................................. 54, 55
Pattern search
Configuration ............................................................ 166
Demodulation process ................................................ 89
Display ........................................................................ 12
Enabling ............................................................ 167, 171
Errors ........................................................................ 246
Found pattern ........................................................... 168
I/Q correlation threshold ........................................... 167
Performing ................................................................ 214
Process ....................................................................... 92
Remote ..................................................................... 310
Selected pattern ........................................................168
Patterns ........................................................................... 140
Adding to standard ....................................................170
Assigning to standard ............................................... 214
Available ................................................................... 170
Coarse synchronization ............................................ 183
Compatible ................................................................170
Configuration .................................................... 140, 168
Copying .....................................................................170
Creating .................................................................... 170
Definition ................................................................... 171
Definition (remote) .................................................... 312
Deleting .....................................................................171
Details ....................................................................... 171
Displaying ................................................................. 170
Editing ....................................................................... 170
Enabling ............................................................ 168, 171
Fine synchronization ................................................. 183
Managing .................................................................. 217
Name ................................................................ 140, 172
Offset ........................................................................ 141
Prefix .........................................................................170
Reference for result range ........................................ 174
Removing from standard .......................................... 170
Restoring .................................................................. 129
Selected .................................................................... 169
Standard ................................................................... 169
Symbol check ............................................................. 96
Symbol check (demodulation process) ....................... 90
Symbol format ...........................................................173
Symbols .................................................................... 173
Working with ............................................................. 214
Peak search
Key ............................................................................198
Limits ........................................................................ 197
Mode ......................................................................... 197
Peaks
Absolute .................................................................... 198
Formula .....................................................................430
Marker positioning .................................................... 198
Next .......................................................................... 198
Softkey ...................................................................... 198
Phase
Distortion, effect ........................................................ 109
Formula .....................................................................425
Wrap (result type) ....................................................... 44
User Manual 1176.8516.02 ─ 06 461
R&S ® FPS-K70 Index
Phase error
Definition ................................................................... 103
Formula .....................................................................425
Result type .................................................................. 43
RMS, peak (formulae) ...............................................428
Phase Error
Result type .................................................................. 44
Phase shift keying
see PSK ...................................................................... 68
Phase unwrap
Unwrap (result type) ................................................... 45
Preamplifier
Setting ...............................................................143, 149
Softkey .............................................................. 143, 149
Prefix
Patterns .................................................................... 170
Presetting
Channels ...................................................................133
Default values ........................................................... 128
Pretrigger ........................................................................ 160
Programming examples
Burst GSM EDGE signal ...........................................405
Continuous QPSK signal .......................................... 404
Protection
RF input (remote) ......................................................288
PSK
Differential ...................................................................73
Error model ............................................................... 100
Mixed forms ................................................................ 74
Modulation type ........................................................ 135
Rotating ...................................................................... 71
Rotating differential ..................................................... 74
Symbol mapping ......................................................... 68
Q
QAM
Error model ............................................................... 100
Modulation type ........................................................ 135
Symbol mapping ......................................................... 80
QPSK
Continuous ................................................................228
Measurement example ............................................. 228
Offset .......................................................................... 75
Offset, symbol mapping .............................................. 75
Programming example ..............................................404
Quadrature Amplitude Modulation
see QAM ..................................................................... 80
Quadrature error
Definition ................................................................... 106
Effect .........................................................................106
Formula .....................................................................428
Preconditions for measurement ................................ 106
Quick Config
Traces ....................................................................... 192
R
Range
X-axis ........................................................................ 153
Range per division
Y-axis ........................................................................ 152
Raw data
Exporting ...................................................................193
Real/Imag (I/Q)
Result type .................................................................. 46
Receive filter ..................................................................... 58
User Manual 1176.8516.02 ─ 06
Record length
Definition ..................................................................... 64
Relationship to sample rate ........................................ 65
Recording tool
Known data ............................................................... 219
Reference
Result range ............................................................. 174
Reference deviation
Definition ................................................................... 111
FSK ........................................................................... 137
Reference filter .................................................................. 59
Reference level ............................................................... 148
Auto level .......................................................... 148, 188
Offset ........................................................................ 148
Unit ........................................................................... 148
Value .........................................................................148
Reference position
X-axis ........................................................................ 153
Y-axis ........................................................................ 152
Reference signal ............................................................. 101
Demodulation process ................................................ 90
Evaluating ................................................................. 192
Generating .................................................................. 90
Reference value
X-axis ........................................................................ 153
Y-axis ........................................................................ 152
Refresh
Softkey ...................................................................... 162
Refreshing
MSRA applications ................................................... 163
MSRA applications (remote) ..................................... 335
Softkey ...................................................................... 163
Remote commands
Basics on syntax ....................................................... 264
Boolean values ......................................................... 268
Capitalization ............................................................ 266
Character data .......................................................... 268
Data blocks ............................................................... 269
Numeric values ......................................................... 267
Optional keywords .................................................... 266
Parameters ............................................................... 267
Strings .......................................................................269
Suffixes ..................................................................... 266
Resetting
RF input protection ................................................... 288
Restoring
Channel settings ....................................................... 133
Factory settings ........................................................ 129
Pattern files ............................................................... 129
Standard files .................................................... 129, 131
Result display
Configuration (remote) .............................................. 357
Troubleshooting ........................................................ 255
Result displays
Data sources ...............................................................14
Result length ................................................................... 118
Display ........................................................................ 12
Known data ............................................................... 124
QAM modulation ......................................................... 80
Ranges ..................................................................... 174
Result range
Alignment .......................................................... 119, 175
Alignment (known data) ............................................ 124
Configuration ............................................................ 173
Defining .....................................................................220
Definition ................................................................... 117
Demodulation process ................................................ 89
462
R&S ® FPS-K70 Index
Display ...................................................................... 117
Evaluating ................................................................. 188
Length ............................................................... 118, 174
Offset ........................................................................ 175
Overlapping .............................................................. 255
Reference ................................................................. 174
Remote ..................................................................... 315
Run-In/out ................................................................. 119
Selecting ................................................................... 163
Result Summary
Configuration .............................................................. 50
Display points per symbol ......................................... 121
Evaluations ............................................................... 427
Formulae ...................................................................428
Formulae (FSK) ........................................................ 429
Result type .................................................................. 47
Result type
Display ........................................................................ 13
Transformation ..........................................................202
Window configuration ............................................... 202
Result types
Bit error rate (BER) ..................................................... 20
Capture buffer ............................................................. 15
Channel Frequency Response Group Delay .............. 22
Channel Frequency Response Magnitude ................. 22
Constellation Frequency ............................................. 23
Constellation I/Q ......................................................... 24
Constellation I/Q (Rotated) ......................................... 25
Equalizer ..................................................................... 17
Error vector ................................................................. 16
Error Vector Magnitude (EVM) ................................... 26
Eye Diagram Frequency ............................................. 27
Eye Diagram Imag (Q) ................................................ 28
Eye Diagram Real (I) .................................................. 29
Frequency Absolute .................................................... 29
Frequency Error Absolute ........................................... 32
Frequency Error Relative ............................................ 33
Frequency Relative ..................................................... 31
Frequency Response Group Delay ............................ 34
Frequency Response Magnitude ................................ 35
Frequency Response Phase ...................................... 36
Impulse Response Magnitude .................................... 37
Impulse Response Phase ........................................... 38
Impulse Response Real/Imag .....................................38
Magnitude Absolute .................................................... 39
Magnitude Error .......................................................... 42
Magnitude Overview Absolute .................................... 40
Magnitude Relative ..................................................... 42
Meas & Ref ................................................................. 15
Modulation accuracy ................................................... 17
Modulation errors ........................................................ 16
Overview ..................................................................... 18
Phase Error .................................................................43
Phase Unwrap ............................................................ 45
Phase Wrap ................................................................ 44
Real/Imag (I/Q) ........................................................... 46
Result Summary ......................................................... 47
SCPI parameters ........................................................ 18
Symbol Table .............................................................. 51
Symbols ...................................................................... 16
Vector Frequency ....................................................... 52
Vector I/Q ....................................................................53
Results
Retrieving (remote) ................................................... 370
Updating the display ................................................. 163
Updating the display (remote) ...................................335
RF attenuation
Auto .......................................................................... 149
Manual ...................................................................... 149
RF input ...........................................................................143
Overload protection (remote) .................................... 288
Remote ..................................................................... 288
RHO
Formula .....................................................................428
RMS average
Formula .....................................................................431
Roll-off factor (Alpha)
Measurement filter .................................................... 186
Transmit filter ............................................................ 138
Rotating Differential PSK
Symbol mapping ......................................................... 74
Rotating PSK
Symbol mapping ......................................................... 71
RRC filter ...........................................................................58
RUN CONT
Key ............................................................................161
RUN SINGLE
Key ............................................................................162
Run-in
Bursts ........................................................................140
S
Sample rate ............................................................... 58, 121
Basics ......................................................................... 56
Definition ............................................................... 63, 64
Max. usable I/Q bandwidth ......................................... 64
Maximum .................................................................... 64
Relationship to bandwidth ...........................................65
Relationship to symbol rate ........................................ 64
Remote ..................................................................... 301
Setting .......................................................................156
Saving
Settings ..................................................................... 131
Scaling
Automatically .................................................... 151, 189
Diagrams, changing .................................................. 223
X-axis ................................................................ 150, 224
X-axis (automatically) ............................................... 153
X-axis, y-axis (default) .............................................. 153
Y-axis ........................................................ 150, 223, 224
Y-axis (remote control) ............................................. 300
Y-axis (statistics) ....................................................... 152
Search
Direction (Real or Imag) ............................................197
Tolerance (Burst Search) ..........................................166
Search limits
Activating .................................................................. 197
Secure user mode
Storage location ........................................................ 130
Select Result Rng
Softkey ...................................................................... 163
Sequencer ......................................................................... 11
Aborting (remote) ...................................................... 335
Activating (remote) ....................................................336
Mode (remote) .......................................................... 336
Remote ..................................................................... 333
Settings
File name .................................................................. 130
Restoring files ................................................... 129, 131
Storage location ........................................................ 130
User Manual 1176.8516.02 ─ 06 463
R&S ® FPS-K70 Index
Settings files
Deleting .....................................................................131
Loading ..................................................................... 131
Saving ....................................................................... 131
Signal capture ................................................................. 154
Remote control ......................................................... 301
Signal description
Configuration ............................................................ 134
Configuration (remote) .............................................. 276
Pattern ...................................................................... 140
Softkey ...................................................................... 134
Signal model ................................................................... 100
FSK ........................................................................... 110
Signal source
Remote ..................................................................... 288
Signal structure
Burst settings ............................................................ 140
Configuration ............................................................ 138
Remote ..................................................................... 284
Signal type
Continuous/Burst Signal ........................................... 139
Single sweep
Softkey ...................................................................... 162
Single zoom .................................................................... 205
Slope
Trigger .............................................................. 161, 306
Softkeys
Amplitude Config ...................................................... 147
Auto Level ......................................................... 148, 188
Capture Offset .......................................................... 161
Center ....................................................................... 146
Continue Single Sweep ............................................ 162
Continuous Sweep ....................................................161
Display configuration ................................................ 201
Export ....................................................................... 207
External .....................................................................159
Free Run ................................................................... 159
Frequency Config ..................................................... 146
I/Q Power .................................................................. 160
IF Power ................................................................... 159
Import ........................................................................207
Input Source Config .................................................. 142
Input/Frontend .......................................................... 142
IQ Export ...................................................................207
IQ Import ................................................................... 207
Lower Level Hysteresis .............................................189
Marker Config ........................................................... 194
Marker to Trace ........................................................ 196
Meastime Auto .......................................................... 189
Meastime Manual ..................................................... 189
Min ............................................................................ 198
ModAcc Limits .......................................................... 200
Next Min ....................................................................198
Next Peak ................................................................. 198
Norm/Delta ................................................................196
Outputs Config .......................................................... 144
Peak ..........................................................................198
Preamp ............................................................. 143, 149
Ref Level ...................................................................148
Ref Level Offset ........................................................ 148
Refresh ..................................................................... 163
RF Atten Auto ........................................................... 149
RF Atten Manual ....................................................... 149
Signal Capture .......................................................... 154
Signal Description ..................................................... 134
Single Sweep ............................................................ 162
Trace 1/2/3/4 .............................................................192
User Manual 1176.8516.02 ─ 06
Trace Config ............................................................. 190
Trigger Offset ............................................................ 160
Trigger/Gate Config .................................................. 157
Upper Level Hysteresis .............................................189
Window configuration ............................................... 201
Specifics for
Configuration ............................................................ 133
Spectrum
Result type transformation ........................................ 202
SR
see Symbol rate .......................................................... 12
Standards
see Digital standards ................................................ 129
Statistic count .................................................................. 162
Display ........................................................................ 12
Statistics
Formulae ...................................................................430
Oversampling ............................................................203
Result type transformation ........................................ 202
Status registers
Description ................................................................ 392
Querying ................................................................... 397
STAT:QUES:POW .................................................... 288
Status reporting system .................................................. 391
StdDev
Formula .....................................................................430
Storage location
Secure user mode .................................................... 130
Settings ..................................................................... 130
Suffixes
Common ................................................................... 269
Remote commands ...................................................266
Support ............................................................................262
Swap IQ .......................................................................... 157
Remote ..................................................................... 302
Sweep
Aborting ............................................................ 161, 162
Configuration (remote) ...................................... 307, 332
Count, see Statistic count ......................................... 162
Settings ..................................................................... 161
Symbol check
Algorithm .....................................................................96
Demodulation ..............................................................96
Patterns ...................................................................... 96
Symbol decisions
Algorithm .....................................................................93
Demodulation ..............................................................93
Demodulation process ................................................ 89
Known data ................................................................. 94
Symbol error rate (SER)
Fine synchronization ................................................. 184
Symbol mapping ....................................................... 67, 137
APSK .......................................................................... 86
ASK .............................................................................85
Differential PSK .......................................................... 73
FSK ............................................................................. 77
MSK ............................................................................ 79
Offset QPSK ............................................................... 75
OOK ............................................................................ 85
PSK .............................................................................68
QAM ............................................................................80
Rotating differentialPSK ..............................................74
Rotating PSK .............................................................. 71
User-defined ............................................................... 87
Wizard (mapwiz) ......................................................... 87
Symbol number
Result range start ..................................................... 175
464
R&S ® FPS-K70 Index
Symbol rate ............................................................. 121, 137
Basics ......................................................................... 56
Display ........................................................................ 12
MSRA mode ............................................................. 124
Relationship to sample rate ........................................ 64
Remote ..................................................................... 282
Symbol Rate Error ...........................................................178
Symbol Rate Error (SRE)
Definition ................................................................... 103
Symbol tables
Result type .................................................................. 51
Symbols
Data source ................................................................ 16
Format, patterns ....................................................... 173
Highlighting ............................................................... 203
Patterns .................................................................... 173
Result types ................................................................ 16
Window Configuration ...............................................203
Synchronization ...............................................................101
Coarse ...................................................................... 183
Demodulation ............................................................180
Demodulation process ................................................ 90
Fine ........................................................................... 183
Known data ....................................................... 183, 184
Patterns .................................................................... 183
Remote ..................................................................... 318
Symbol error rate (SER) ........................................... 184
Syntax
Known data files ....................................................... 423
T
Trace Export
Configuration ............................................................ 193
Data mode ................................................................ 193
Header information ................................................... 193
Storage location ........................................................ 194
Traces ............................................................................. 192
Averaging, formulae ..................................................431
Capture Buffer (remote) ............................................ 375
Cartesian Diagrams (remote) ................................... 376
Configuration ............................................................ 190
Configuring (remote control) ..................................... 338
Equalizer (remote) .................................................... 377
Evaluation ................................................................. 192
Export format ............................................................ 194
Exporting ...........................................................194, 207
Exporting data ...........................................................226
Measurement signal ................................................. 192
Mode ......................................................................... 191
Mode (remote) .......................................................... 339
Polar Diagrams (remote) .......................................... 376
Reference signal ....................................................... 192
Result Summary (remote) ......................................... 376
Retrieving data (remote) ........................................... 371
Selecting ................................................................... 191
Settings (remote control) .......................................... 338
Settings, predefined .................................................. 192
Symbols (remote) ..................................................... 376
Troubleshooting ........................................................ 255
Transmit filter .................................................................... 58
Alpha/BT ................................................................... 138
Predefined ................................................................ 419
Type .......................................................................... 138
User-defined ............................................................. 138
Using as measurement filter ..................................... 186
Trigger
Configuration ............................................................ 157
Drop-out time ............................................................ 161
External (remote) ...................................................... 306
Holdoff ...................................................................... 161
Hysteresis ................................................................. 160
Offset ........................................................................ 160
Output ....................................................................... 144
Remote control ......................................................... 303
Slope .................................................................161, 306
Trigger level .................................................................... 160
External trigger (remote) ........................................... 305
I/Q Power (remote) ................................................... 305
IF Power (remote) ..................................................... 305
Trigger source ................................................................. 159
External .....................................................................159
Free Run ................................................................... 159
I/Q Power .................................................................. 160
IF Power ................................................................... 159
Triggers
MSRA ............................................................... 158, 303
Troubleshooting
Burst search ..............................................................246
Flow chart ................................................................. 244
Frequently asked questions ...................................... 255
Input overload ........................................................... 288
Pattern search .......................................................... 246
Result display ........................................................... 255
Traces ....................................................................... 255
U
Units
Reference level ......................................................... 148
X-axis ........................................................................ 154
X-axis, y-axis ............................................................ 153
Y-axis ........................................................................ 154
Updating
Result display ........................................................... 163
Result display (remote) ............................................. 335
Upper Level Hysteresis ................................................... 189
Usable I/Q bandwidth
Definition ..................................................................... 64
Result display ..................................................... 14, 157
Useful length
Bursts ........................................................................119
User filters
Loading ..................................................................... 138
User manuals ...................................................................... 8
User QAM
Modulation type ........................................................ 135
User sample rate
Definition ..................................................................... 64
V
Vector frequency
Result type .................................................................. 52
Vector I/Q
Result type .................................................................. 53
Video output ............................................................ 144, 289
W
Window configuration .............................................. 201, 202
Data source .............................................................. 202
Remote ..................................................................... 364
User Manual 1176.8516.02 ─ 06 465
R&S ® FPS-K70
Result type ................................................................ 202
Result type transformation ........................................ 202
Window title bar information .............................................. 13
Windows
Adding (remote) ........................................................ 359
Closing (remote) ............................................... 361, 364
Configuring ............................................................... 133
Layout (remote) ........................................................ 361
Maximizing (remote) ................................................. 358
Querying (remote) .............................................360, 361
Replacing (remote) ................................................... 361
Splitting (remote) ...................................................... 358
Types (remote) ......................................................... 359
X
X-axis
Quantize ................................................................... 153
Range ....................................................................... 153
Reference position ............................................ 153, 224
Reference value ................................................153, 224
Scaling ...................................................................... 150
Scaling (default) ........................................................ 153
Scaling automatically ................................................ 153
Scaling, auto ..................................................... 151, 189
Scaling, auto all windows ..........................................189
Units ..........................................................................154
X-value
Marker .......................................................................195
Y
Y-axis
Mix, max values ........................................................ 152
Range ....................................................................... 225
Range per division .................................................... 152
Reference position ............................................ 152, 223
Reference value ................................................152, 223
Scaling ...................................................................... 150
Scaling (statistics) ..................................................... 152
Scaling, auto ..................................... 151, 189, 223, 225
Scaling, auto all windows ..........................................189
Units ..........................................................................154
Z
Zooming
Activating (remote) ....................................................356
Area (Multiple mode, remote) ................................... 356
Area (remote) ............................................................356
Deactivating .............................................................. 205
Multiple mode ........................................................... 205
Multiple mode (remote) ..................................... 356, 357
Remote ..................................................................... 355
Restoring original display ..........................................205
Single mode .............................................................. 205
Single mode (remote) ............................................... 355
User Manual 1176.8516.02 ─ 06
Index
466
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