R&S®FSV3-K7
AM/FM/PM Modulation Analysis
Option
User Manual
(;Üèa2)
1178904902
Version 08
This manual applies to the following R&S®FSV3000 and R&S®FSVA3000 models with firmware version
1.90 and higher:
●
R&S®FSV3004 (1330.5000K04) / R&S®FSVA3004 (1330.5000K05)
●
R&S®FSV3007 (1330.5000K07) / R&S®FSVA3007 (1330.5000K08)
●
R&S®FSV3013 (1330.5000K13) / R&S®FSVA3013 (1330.5000K14)
●
R&S®FSV3030 (1330.5000K30) / R&S®FSVA3030 (1330.5000K31)
●
R&S®FSV3044 (1330.5000K43) / R&S®FSVA3044 (1330.5000K44)
●
R&S®FSV3050 (1330.5000K50) / R&S®FSVA3050 (1330.5000K51)
The following firmware options are described:
●
R&S FSV/A-K7 (1330.5022.02)
© 2022 Rohde & Schwarz GmbH & Co. KG
Muehldorfstr. 15, 81671 Muenchen, Germany
Phone: +49 89 41 29 - 0
Email: info@rohde-schwarz.com
Internet: www.rohde-schwarz.com
Subject to change – data without tolerance limits is not binding.
R&S® is a registered trademark of Rohde & Schwarz GmbH & Co. KG.
All other trademarks are the properties of their respective owners.
1178.9049.02 | Version 08 | R&S®FSV3-K7
The following abbreviations are used throughout this manual: R&S®FSVA3000 is abbreviated as R&S FSVA3000. R&S®FSV3000 is
abbreviated as R&S FSV3000. R&S®FSV/A refers to both the R&S FSV3000 and the R&S FSVA3000. Products of the R&S®SMW
family, e.g. R&S®SMW200A, are abbreviated as R&S SMW.
R&S®FSV3-K7
1.1 Getting started manual................................................................................................. 9
1.2 User manuals and help.................................................................................................9
1.3 Service manual............................................................................................................10
1.4 Instrument security procedures................................................................................ 10
1.5 Printed safety instructions.........................................................................................10
1.6 Data sheets and brochures........................................................................................ 10
1.7 Release notes and open-source acknowledgment (OSA).......................................10
1.8 Application notes, application cards, white papers, etc......................................... 11
Contents
Contents
1 Documentation overview.......................................................................9
2 Welcome to the R&S FSV3 AM/FM/PM Modulation Analysis applica-
tion.........................................................................................................12
2.1 Starting AM/FM/PM Modulation Analysis..................................................................12
2.2 Understanding the display information.................................................................... 13
3 Measurements and result displays.................................................... 16
4 Measurement basics............................................................................27
4.1 Demodulation process............................................................................................... 27
4.2 Demodulation bandwidth........................................................................................... 29
4.3 Sample rate and demodulation bandwidth...............................................................30
4.4 AF triggers................................................................................................................... 31
4.5 AF filters.......................................................................................................................32
4.6 Time domain zoom......................................................................................................32
4.7 I/Q data import and export......................................................................................... 33
5 Configuration........................................................................................35
5.1 Configuration overview.............................................................................................. 35
5.2 Configuration according to standards......................................................................37
5.3 Input and frontend settings........................................................................................39
5.3.1 Input source settings..................................................................................................... 39
5.3.1.1 Radio frequency input................................................................................................... 39
5.3.1.2 Settings for input from I/Q data files..............................................................................42
5.3.2 Settings for input from I/Q data files..............................................................................43
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5.3.3 Amplitude settings.........................................................................................................44
5.3.4 Frequency..................................................................................................................... 48
5.4 Trigger configuration..................................................................................................49
5.4.1 Trigger source settings..................................................................................................50
5.4.2 Trigger input and output settings...................................................................................53
5.5 Data acquisition.......................................................................................................... 55
5.5.1 Bandwidth settings........................................................................................................ 55
5.5.2 Sweep settings..............................................................................................................57
5.6 Demodulation display.................................................................................................60
5.7 Demodulation.............................................................................................................. 60
5.7.1 Basic demodulation measurement parameters (Demod)..............................................60
5.7.2 Demodulation spectrum................................................................................................ 63
5.7.2.1 AF evaluation................................................................................................................ 64
Contents
5.7.2.2 RF evaluation................................................................................................................ 65
5.7.3 AF filter..........................................................................................................................66
5.7.4 Scaling.......................................................................................................................... 69
5.7.4.1 AF evaluation................................................................................................................ 70
5.7.4.2 RF evaluation................................................................................................................ 72
5.7.5 Units.............................................................................................................................. 73
5.7.6 Result table settings......................................................................................................74
5.7.7 Settling time.................................................................................................................. 76
5.8 Output settings............................................................................................................78
5.8.1 Output settings.............................................................................................................. 78
5.8.2 Analog demod output settings.......................................................................................79
5.9 Adjusting settings automatically...............................................................................80
6 Analysis................................................................................................ 85
6.1 Trace settings..............................................................................................................85
6.2 Spectrogram settings................................................................................................. 89
6.2.1 General spectrogram settings....................................................................................... 89
6.2.2 Color map settings........................................................................................................ 93
6.3 Trace / data export configuration.............................................................................. 94
6.4 Working with markers in the R&S FSV3 AM/FM/PM Modulation Analysis applica-
tion................................................................................................................................98
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6.4.1 Marker settings..............................................................................................................98
6.4.1.1 Individual marker setup................................................................................................. 98
6.4.1.2 General marker settings..............................................................................................101
6.4.2 Marker search settings and positioning functions....................................................... 103
6.4.2.1 Marker search settings................................................................................................103
6.4.2.2 Positioning functions................................................................................................... 104
6.4.3 Marker search settings for spectrograms....................................................................105
6.4.4 Marker function configuration......................................................................................108
6.4.4.1 Measuring characteristic bandwidths (n db down marker)..........................................109
6.4.4.2 Phase noise measurement marker..............................................................................111
6.4.4.3 Marker peak list........................................................................................................... 113
6.4.4.4 Measuring the power in a channel (band power marker)............................................ 117
6.4.4.5 AF phase marker.........................................................................................................120
Contents
6.4.4.6 Deactivating all marker functions................................................................................ 121
7 How to perform measurements in the R&S FSV3 AM/FM/PM Modu-
lation Analysis application................................................................122
7.1 How to export trace data and numerical results.................................................... 123
8 Measurement example: demodulating an FM signal...................... 125
9 Optimizing and troubleshooting the measurement........................ 130
10 Remote commands for AM/FM/PM Modulation Analysis............... 131
10.1 Introduction............................................................................................................... 132
10.1.1 Conventions used in descriptions............................................................................... 133
10.1.2 Long and short form.................................................................................................... 133
10.1.3 Numeric suffixes..........................................................................................................134
10.1.4 Optional keywords.......................................................................................................134
10.1.5 Alternative keywords................................................................................................... 134
10.1.6 SCPI parameters.........................................................................................................135
10.1.6.1 Numeric values........................................................................................................... 135
10.1.6.2 Boolean....................................................................................................................... 136
10.1.6.3 Character data............................................................................................................ 136
10.1.6.4 Character strings.........................................................................................................137
10.1.6.5 Block data................................................................................................................... 137
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10.2 Common suffixes...................................................................................................... 137
10.3 Activating analog modulation analysis...................................................................137
10.4 Configuring the measurement................................................................................. 141
10.4.1 Managing standard settings........................................................................................ 141
10.4.2 Configuring the input................................................................................................... 142
10.4.2.1 RF input.......................................................................................................................143
10.4.2.2 Configuring file input................................................................................................... 145
10.4.2.3 Working with power sensors....................................................................................... 147
10.4.2.4 External generator control...........................................................................................157
Contents
Configuring power sensors......................................................................................... 147
Configuring power sensor measurements.................................................................. 148
Triggering with power sensors.................................................................................... 154
Measurement configuration.........................................................................................157
Interface configuration.................................................................................................160
Source calibration....................................................................................................... 162
10.4.3 Configuring the output.................................................................................................164
10.4.4 Frequency settings......................................................................................................167
10.4.5 Configuring the vertical axis (amplitude, scaling)........................................................168
10.4.5.1 Amplitude settings.......................................................................................................169
10.4.5.2 Configuring the attenuation......................................................................................... 170
10.4.5.3 Configuring a preamplifier........................................................................................... 173
10.4.5.4 Scaling the Y-axis........................................................................................................175
10.4.6 Configuring data acquisition........................................................................................178
10.4.7 Triggering.................................................................................................................... 182
10.4.7.1 Configuring the triggering conditions...........................................................................182
10.4.7.2 Configuring the trigger output......................................................................................189
10.4.8 Configuring demodulation........................................................................................... 191
10.4.8.1 Basic demodulation settings....................................................................................... 191
10.4.8.2 Time domain zoom settings........................................................................................ 194
10.4.8.3 Configuring the demodulation spectrum..................................................................... 196
AF evaluation.............................................................................................................. 196
RF evaluation.............................................................................................................. 198
10.4.8.4 (Post-processing) AF filters.........................................................................................198
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10.4.8.5 Defining the scaling and units..................................................................................... 204
10.4.8.6 Scaling for AF evaluation............................................................................................ 204
10.4.8.7 Scaling for RF evaluation............................................................................................ 205
10.4.8.8 Units............................................................................................................................ 205
10.4.8.9 Relative demodulation results..................................................................................... 206
10.4.8.10 Settling time................................................................................................................ 209
10.4.9 Adjusting settings automatically.................................................................................. 210
10.5 Capturing data and performing sweeps................................................................. 214
10.6 Configuring the result display................................................................................. 218
10.6.1 General window commands........................................................................................218
10.6.2 Working with windows in the display...........................................................................219
10.7 Retrieving results......................................................................................................226
10.7.1 Retrieving trace results............................................................................................... 226
Contents
10.7.2 Exporting trace results................................................................................................ 229
10.7.3 Retrieving result summary values............................................................................... 232
10.7.4 Formats for returned values: ASCII format and binary format.................................... 237
10.7.5 Reference: ASCII file export format............................................................................ 237
10.8 Analyzing results...................................................................................................... 238
10.8.1 Configuring spectrograms........................................................................................... 238
10.8.1.1 Configuring a spectrogram measurement...................................................................238
10.8.1.2 Configuring the color map........................................................................................... 243
10.8.2 Configuring standard traces........................................................................................ 245
10.8.3 Working with markers remotely...................................................................................252
10.8.3.1 Setting up individual markers...................................................................................... 252
10.8.3.2 General marker settings..............................................................................................259
10.8.3.3 Marker search (spectrograms).................................................................................... 260
Using markers............................................................................................................. 261
Using delta markers.................................................................................................... 265
10.8.3.4 Marker search settings................................................................................................270
10.8.3.5 Positioning the marker................................................................................................ 270
Positioning normal markers.........................................................................................271
Positioning delta markers............................................................................................273
10.8.3.6 Configuring special marker functions.......................................................................... 275
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10.8.4 Marker search (spectrograms).................................................................................... 292
10.8.4.1 Using markers............................................................................................................. 292
10.8.4.2 Using delta markers.................................................................................................... 297
10.8.5 Defining limit checks................................................................................................... 301
10.8.5.1 Configuring limit lines.................................................................................................. 301
10.8.5.2 Managing limit lines.....................................................................................................310
10.8.5.3 Checking the results of a limit check...........................................................................313
Contents
Fixed reference marker settings..................................................................................275
Marker peak lists......................................................................................................... 277
N db down marker.......................................................................................................282
Phase noise measurement marker............................................................................. 285
Band power marker.....................................................................................................286
Configuring and retrieving AF phase marker values................................................... 290
10.8.5.4 Programming example: using limit lines......................................................................314
Example: configuring limit lines...................................................................................314
Example: performing a limit check.............................................................................. 315
10.9 Importing and exporting I/Q data and results........................................................ 317
10.10 Deprecated commands.............................................................................................318
10.11 Programming example............................................................................................. 319
Annex.................................................................................................. 322
A Reference............................................................................................322
A.1 Predefined standards and settings......................................................................... 322
List of Remote Commands (AnalogModAnalysis)..........................325
Index....................................................................................................336
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R&S®FSV3-K7
1 Documentation overview
1.1 Getting started manual
Documentation overview
User manuals and help
This section provides an overview of the R&S FSV/A user documentation. Unless
specified otherwise, you find the documents at:
www.rohde-schwarz.com/manual/FSVA3000
www.rohde-schwarz.com/manual/FSV3000
Further documents are available at:
www.rohde-schwarz.com/product/FSVA3000
www.rohde-schwarz.com/product/FSV3000
Introduces the R&S FSV/A and describes how to set up and start working with the
product. Includes basic operations, typical measurement examples, and general information, e.g. safety instructions, etc.
A printed version is delivered with the instrument. A PDF version is available for download on the Internet.
1.2 User manuals and help
Separate user manuals are provided for the base unit and the firmware applications:
●
Base unit manual
Contains the description of all instrument modes and functions. It also provides an
introduction to remote control, a complete description of the remote control commands with programming examples, and information on maintenance, instrument
interfaces and error messages. Includes the contents of the getting started manual.
●
Firmware application manual
Contains the description of the specific functions of a firmware application, including remote control commands. Basic information on operating the R&S FSV/A is
not included.
The contents of the user manuals are available as help in the R&S FSV/A. The help
offers quick, context-sensitive access to the complete information for the base unit and
the firmware applications.
All user manuals are also available for download or for immediate display on the Internet.
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1.3 Service manual
1.4 Instrument security procedures
Documentation overview
Release notes and open-source acknowledgment (OSA)
Describes the performance test for checking the rated specifications, module replacement and repair, firmware update, troubleshooting and fault elimination, and contains
mechanical drawings and spare part lists.
The service manual is available for registered users on the global Rohde & Schwarz
information system (GLORIS):
R&S®FSVA3000/FSV3000 Service manual
Deals with security issues when working with the R&S FSV/A in secure areas. It is
available for download on the Internet.
1.5 Printed safety instructions
Provides safety information in many languages. The printed document is delivered with
the product.
1.6 Data sheets and brochures
The data sheet contains the technical specifications of the R&S FSV/A. It also lists the
firmware applications and their order numbers, and optional accessories.
The brochure provides an overview of the instrument and deals with the specific characteristics.
See www.rohde-schwarz.com/brochure-datasheet/FSV3000 /
www.rohde-schwarz.com/brochure-datasheet/FSVA3000
1.7 Release notes and open-source acknowledgment (OSA)
The release notes list new features, improvements and known issues of the current
firmware version, and describe the firmware installation.
The software makes use of several valuable open source software packages. An opensource acknowledgment document provides verbatim license texts of the used open
source software.
See www.rohde-schwarz.com/firmware/FSV3000 /
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1.8 Application notes, application cards, white papers,
Documentation overview
Application notes, application cards, white papers, etc.
www.rohde-schwarz.com/firmware/FSVA3000
etc.
These documents deal with special applications or background information on particular topics.
See www.rohde-schwarz.com/application/FSV3000 /
www.rohde-schwarz.com/application/FSVA3000
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2 Welcome to the R&S FSV3 AM/FM/PM
Welcome to the R&S FSV3 AM/FM/PM Modulation Analysis application
Starting AM/FM/PM Modulation Analysis
Modulation Analysis application
The R&S FSV3 AM/FM/PM Modulation Analysis application option converts the
R&S FSV/A into an analog modulation analyzer for amplitude-, frequency- or phasemodulated signals. It measures not only characteristics of the useful modulation, but
also factors such as residual FM or synchronous modulation.
The digital signal processing in the R&S FSV/A, used in the Spectrum application for
digital IF filters, is also ideally suited for demodulating AM, FM, or PM signals. The
firmware option R&S FSV3-K7 provides the necessary measurement functions.
The R&S FSV3 AM/FM/PM Modulation Analysis application features:
●
AM, FM, and PM demodulation, with various result displays:
– Modulation signal versus time
– Spectrum of the modulation signal (FFT)
– RF signal power versus time
– Spectrum of the RF signal
●
Determining maximum, minimum and average or current values in parallel over a
selected number of measurements
●
Maximum accuracy and temperature stability due to sampling (digitization) already
at the IF and digital down-conversion to the baseband (I/Q)
●
Error-free AM to FM conversion and vice versa, without deviation errors, frequency
response or frequency drift at DC coupling
●
Relative demodulation, in relation to a user-defined or measured reference value
This user manual contains a description of the functionality that the application provides, including remote control operation.
All functions not discussed in this manual are the same as in the base unit and are
described in the R&S FSV/A User Manual. The latest version is available for download
at the product homepage http://www.rohde-schwarz.com/product/FSVA3000.
Installation
You can find detailed installation instructions in the R&S FSV/A Getting Started manual
or in the Release Notes.
2.1 Starting AM/FM/PM Modulation Analysis
AM/FM/PM Modulation Analysis is a separate application on the R&S FSV/A.
To activate AM/FM/PM Modulation Analysis
1. Select the [MODE] key.
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Welcome to the R&S FSV3 AM/FM/PM Modulation Analysis application
Understanding the display information
A dialog box opens that contains all operating modes and applications currently
available on your R&S FSV/A.
2. Select the "AM FM PM Analog Demod" item.
The R&S FSV/A opens a new channel for the application for analog modulation
analysis.
The measurement is started immediately with the default settings. It can be configured
in the analog modulation analysis "Overview" dialog box, which is displayed when you
select the "Overview" softkey from any menu (see Chapter 5.1, "Configuration over-
view", on page 35).
Multiple Channels and Sequencer Function
When you activate an application, a new channel is created which determines the
measurement settings for that application ("Channel"). The same application can be
activated with different measurement settings by creating several "Channel"s 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, to perform the configured measurements consecutively, a
Sequencer function is provided.
If activated, the measurements configured in the currently defined "Channel"s are performed one after the other in the order of the tabs. The currently active measurement is
indicated by a
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 FSV/A User Manual.
symbol in the tab label.
2.2 Understanding the display information
The following figure shows a measurement diagram during analog modulation analysis. All different information areas are labeled. They are explained in more detail in the
following sections.
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Welcome to the R&S FSV3 AM/FM/PM Modulation Analysis application
Understanding the display information
1
2
3
4
5
1 = Channel bar for firmware and measurement settings
2 = Diagram area
3 = Window title bar with diagram-specific (trace) information
4 = Instrument status bar with error messages and date/time display
5 = Diagram footer with diagram-specific information, depending on result display
Channel bar information
In the Analog Modulation Analysis application, the R&S FSV/A shows the following settings:
Table 2-1: Information displayed in the channel bar in the application for analog modulation analysis
Ref Level Reference level
m.+el.Att Mechanical and electronic RF attenuation
Offset Reference level offset
AQT Measurement time for data acquisition.
RBW Resolution bandwidth
DBW Demodulation bandwidth
Freq Center frequency for the RF signal
Window title bar information
For each diagram, the header provides the following information:
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Welcome to the R&S FSV3 AM/FM/PM Modulation Analysis application
Understanding the display information
1 2 345 6 7 8 9
Figure 2-1: Window title bar information in the application for analog modulation analysis
1 = Window number
2 = Window type
3 = Trace color
4 = Trace number
5 = Detector
6 = Trace mode
7 = Reference value (at the defined reference position)
8 = AF coupling (AC/DC), only in AF time domains, if applicable
9 = Results are selected for demodulation output
Diagram footer information
The diagram footer (beneath the diagram) contains the following information, depending on the evaluation:
"RF Spectrum"
CF: Center frequency
of input signal
RF Time domain
CF: Center frequency
of input signal
AF Spectrum
AF CF: center frequency of demodulated signal
AF Time domain
CF: Center frequency
of input signal
Sweep points Span: measured span
Sweep points Time per division
Sweep points AF Span: evaluated span
Sweep points Time per division
For most modes, the number of sweep points shown in the display are indicated in the
diagram footer. In zoom mode, the (rounded) number of currently displayed points are
indicated.
Status bar information
Global instrument settings, the instrument status and any irregularities are indicated in
the status bar beneath the diagram.
Furthermore, the progress of the current operation is displayed in the status bar.
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3 Measurements and result displays
Measurements and result displays
Access: "Overview" > "Display Config"
Or: [MEAS] > "Display Config"
The data that was measured by the R&S FSV/A can be evaluated using various different methods. In the Analog Modulation Analysis application, up to six evaluation methods can be displayed simultaneously in separate windows. The results can be displayed as absolute deviations or relative to a reference value or level.
The abbreviation "AF" (for Audio Frequency) refers to the demodulated AM, FM or PM
signal.
Basis for evaluation
All evaluations are based on the I/Q data set acquired during the measurement. The
spectrum of the modulated signal to be evaluated is determined by the demodulation
bandwidth. However, it can be restricted to a limited span ("AF Span") if only part of the
signal is of interest. Furthermore, the time base for evaluations in the time domain can
be restricted to analyze a smaller extract in more detail, see Chapter 4.6, "Time
domain zoom", on page 32.
AM Time Domain...........................................................................................................16
FM Time Domain...........................................................................................................17
PM Time Domain...........................................................................................................18
AM Spectrum................................................................................................................ 19
FM Spectrum.................................................................................................................20
PM Spectrum................................................................................................................ 21
RF Time Domain...........................................................................................................22
RF Spectrum.................................................................................................................23
Result Summary............................................................................................................24
Marker Table................................................................................................................. 26
Marker Peak List........................................................................................................... 26
AM Time Domain
Displays the modulation depth of the demodulated AM signal (in %) versus time.
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Measurements and result displays
Optionally, the settling time can be evaluated and displayed, see Chapter 5.7.7, "Set-
tling time", on page 76.
Remote command:
LAY:ADD? '1',RIGH,'XTIM:AM:REL'
(See LAYout:ADD[:WINDow]? on page 219)
FM Time Domain
Displays the frequency spectrum of the demodulated FM signal versus time.
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Measurements and result displays
Optionally, the settling time can be evaluated and displayed, see Chapter 5.7.7, "Set-
tling time", on page 76.
Remote command:
LAY:ADD? '1',RIGH,'XTIM:FM'
(See LAYout:ADD[:WINDow]? on page 219)
PM Time Domain
Displays the phase deviations of the demodulated PM signal (in rad or °) versus time.
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Measurements and result displays
Optionally, the settling time can be evaluated and displayed, see Chapter 5.7.7, "Set-
tling time", on page 76.
Remote command:
LAY:ADD? '1',RIGH,'XTIM:PM'
(See LAYout:ADD[:WINDow]? on page 219)
AM Spectrum
Displays the modulation depth of the demodulated AM signal (in % or dB) versus AF
span. The spectrum is calculated from the demodulated AM signal in the time domain
via FFT.
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Measurements and result displays
Note: If a high pass or low pass AF filter is defined, the filter is indicated by a vertical
red line in the spectrum display.
Remote command:
LAY:ADD? '1',RIGH,'XTIMe:AM:REL:AFSPectrum1'
(see LAYout:ADD[:WINDow]? on page 219)
FM Spectrum
Displays the frequency deviations of the demodulated FM signal (in Hz or dB) versus
AF span. The spectrum is calculated from the demodulated AM signal in the time
domain via FFT.
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Measurements and result displays
Note: If a high pass or low pass AF filter is defined, the filter is indicated by a vertical
red line in the spectrum display.
Remote command:
LAY:ADD? '1',RIGH,'XTIMe:FM:AFSPectrum1'
(see LAYout:ADD[:WINDow]? on page 219)
PM Spectrum
Displays the phase deviations of the demodulated PM signal (in rad, ° or dB) versus
AF span. The spectrum is calculated from the demodulated AM signal in the time
domain via FFT.
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Measurements and result displays
Note: If a high pass or low pass AF filter is defined, the filter is indicated by a vertical
red line in the spectrum display.
Remote command:
LAY:ADD? '1',RIGH,'XTIMe:PM:AFSPectrum1'
(see LAYout:ADD[:WINDow]? on page 219)
RF Time Domain
Displays the RF power of the input signal versus time. The level values represent the
magnitude of the I/Q data set.
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Measurements and result displays
Optionally, the settling time can be evaluated and displayed, see Chapter 5.7.7, "Set-
tling time", on page 76.
Remote command:
LAY:ADD? '1',RIGH,'XTIM:AM'
(see LAYout:ADD[:WINDow]? on page 219)
RF Spectrum
Displays the spectrum of the input signal. In contrast to the Spectrum application, the
frequency values are determined using FFT from the recorded I/Q data set.
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Measurements and result displays
Remote command:
LAY:ADD? '1',RIGH,'XTIM:SPECTRUM'
(see LAYout:ADD[:WINDow]? on page 219)
Result Summary
The "result summary" displays the results of the demodulation functions for all windows
in a table.
The following general results are provided:
For each demodulation, the following results are provided:
Label Description
"Carr Power" Measured carrier power
"Carr Offset" Carrier offset to nominal center frequency
"Mod. Depth" Modulation depth
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Measurements and result displays
Table 3-1: Result summary description
Label Description
"Settling Time" Time after which signal remains in a specified value range.
Only evaluated and displayed if enabled, see Chapter 5.7.7, "Settling time",
on page 76.
"+Peak" Positive peak (maximum)
"-Peak" Negative peak (minimum)
"+/-Peak/2" Average of positive and negative peaks
"RMS" Root Mean Square value
"Mod Freq" Modulation frequency
"SINAD" Signal-to-noise-and-distortion
(Calculated only if AF Spectrum is displayed)
Measures the ratio of the total power to the power of noise and harmonic distortions.
The noise and harmonic power is calculated inside the AF spectrum span. The DC
offset is removed before the calculation.
"DISTORT" Modulation distortion in %
(Calculated only if "SINAD" is also calculated)
Measures the distortion of the modulation in relation to the total power of the signal
inside the AF spectrum span. Indicates the quality of the modulation.
"THD" Total harmonic distortion
The ratio of the harmonics to the fundamental and harmonics. All harmonics inside
the AF spectrum span are considered up to the tenth harmonic.
(Calculated only if AF Spectrum is displayed)
Note: Relative demodulation results. Optionally, the demodulation results in relation to
user-defined or measured reference values are determined. See Chapter 5.7.6, "Result
table settings", on page 74.
In addition, the following general information for the input signal is provided:
●
"Carrier Power": the power of the carrier without modulation
●
"Carrier Offset": the deviation of the calculated carrier frequency to the ideal carrier
frequency
●
"Modulation Depth" (AM or "RF Time Domain" only): the difference in amplitude the
carrier signal is modulated with
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Measurements and result displays
Remote command:
LAY:ADD? '1',RIGH,RSUM, see LAYout:ADD[:WINDow]? on page 219
Results:
Chapter 10.7.3, "Retrieving result summary values", on page 232
Marker Table
Displays a table with the current marker values for the active markers.
This table is displayed automatically if configured accordingly.
Tip: To navigate within long marker tables, simply scroll through the entries with your
finger on the touchscreen.
Remote command:
LAY:ADD? '1',RIGH, MTAB, see LAYout:ADD[:WINDow]? on page 219
Results:
CALCulate<n>:MARKer<m>:X on page 254
CALCulate<n>:MARKer<m>:Y? on page 254
Marker Peak List
The marker peak list determines the frequencies and levels of peaks in the spectrum or
time domain. How many peaks are displayed can be defined, as well as the sort order.
In addition, the detected peaks can be indicated in the diagram. The peak list can also
be exported to a file for analysis in an external application.
Tip: To navigate within long marker peak lists, simply scroll through the entries with
your finger on the touchscreen.
Remote command:
LAY:ADD? '1',RIGH, PEAK, see LAYout:ADD[:WINDow]? on page 219
Results:
CALCulate<n>:MARKer<m>:X on page 254
CALCulate<n>:MARKer<m>:Y? on page 254
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4 Measurement basics
4.1 Demodulation process
Measurement basics
Demodulation process
Some background knowledge on basic terms and principles used in Analog Modulation
Analysis measurements is provided here for a better understanding of the required
configuration settings.
● Demodulation process............................................................................................ 27
● Demodulation bandwidth.........................................................................................29
● Sample rate and demodulation bandwidth..............................................................30
● AF triggers...............................................................................................................31
● AF filters..................................................................................................................32
● Time domain zoom..................................................................................................32
● I/Q data import and export...................................................................................... 33
The demodulation process is shown in Figure 4-1. All calculations are performed simultaneously with the same I/Q data set. Magnitude (= amplitude) and phase of the complex I/Q pairs are determined. The frequency result is obtained from the differential
phase.
For details on general I/Q data processing in the R&S FSV/A, refer to the reference
part of the I/Q Analysis remote control description in the R&S FSV/A User Manual.
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Measurement basics
Demodulation process
Figure 4-1: Block diagram of software demodulator
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Measurement basics
Demodulation bandwidth
The AM DC, FM DC and PM DC raw data of the demodulators is fed into the "Trace
Arithmetic" block that combines consecutive data sets. Possible trace modes are:
Clear Write, Max Hold, Min Hold and Average. The output data of the "Trace Arithmetic" block can be read via remote control ([SENS:]ADEM:<evaluation>:RES?,
see [SENSe:]ADEMod:AM[:ABSolute][:TDOMain]:RESult? on page 227.
The collected measured values are evaluated by the selected detector. The result is
displayed on the screen and can be read out via remote control.
In addition, important parameters are calculated:
●
A counter determines the modulation frequency for AM, FM, and PM.
●
average power = carrier power (RF power)
●
average frequency = carrier frequency offset (FM)
●
The modulation depth or the frequency or phase deviation; the deviations are
determined from the trace data
AC coupling is possible with FM and PM display.
4.2 Demodulation bandwidth
The demodulation bandwidth determines the span of the signal that is demodulated. It
is not the 3-dB bandwidth of the filter, but the useful bandwidth which is distortion-free
regarding phase and amplitude.
Therefore the following formulas apply:
●
AM: demodulation bandwidth ≥ 2 x modulation frequency
●
FM: demodulation bandwidth ≥ 2 x (frequency deviation + modulation frequency)
●
PM: demodulation bandwidth ≥ 2 x modulation frequency x (1 + phase deviation)
If the center frequency of the analyzer is not set exactly to the signal frequency, the
demodulation bandwidth must be increased by the carrier offset, in addition to the
requirement described above. The bandwidth must also be increased if FM or PM AC
coupling is selected.
In general, select the demodulation bandwidth as narrow as possible to improve the
S/N ratio. The residual FM caused by noise floor and phase noise increases dramatically with the bandwidth, especially with FM.
For help on determining the adequate demodulation bandwidth, see "Determining the
demodulation bandwidth" on page 130.
A practical example is described in Chapter 8, "Measurement example: demodulating
an FM signal", on page 125.
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4.3 Sample rate and demodulation bandwidth
Measurement basics
Sample rate and demodulation bandwidth
The maximum demodulation bandwidths that can be obtained during the measurement, depending on the sample rate, are listed in the tables below for different demodulation filter types. The allowed value range of the measurement time and trigger offset
depends on the selected demodulation bandwidth and demodulation filter. If the AF filter or the AF trigger are not active, the measurement time increases by 20 %.
A maximum of 24 million samples can be captured, assuming sufficient memory is
available; thus the maximum measurement time can be determined according to the
following formula:
Meas.time
The minimum trigger offset is (-Meas.time
Table 4-1: Available demodulation bandwidths and corresponding sample rates
Demodulation BW Sample Rate (Flat Top) Sample Rate (Gaussian Top)
= Sample count
max
/ sample rate
max
max
)
100 Hz 122.0703125 Hz 400 Hz
200 Hz 244.140625 Hz 800 Hz
400 Hz 488.28125 Hz 1.6 kHz
800 Hz 976.5625 Hz 3.2 kHz
1.6 kHz 1.953125 kHz 6.4 kHz
3.2 kHz 3.90625 kHz 12.8 kHz
6.4 kHz 7.8125 kHz 25.6 kHz
12.5 kHz 15.625 kHz 50 kHz
25 kHz 31.25 kHz 100 kHz
50 kHz 62.5 kHz 200 kHz
100 kHz 125 kHz 400 kHz
200 kHz 250 kHz 800 kHz
400 kHz 500 kHz 1.6 MHz
800 kHz 1 MHz 3.2 MHz
1.6 MHz 2 MHz 6.4 MHz
3 MHz 4 MHz 12 MHz
5 MHz 8 MHz 20 MHz
8 MHz 16 MHz 32 MHz
10 MHz 32 MHz 40 MHz
18 MHz 32 MHz 72 MHz
28 MHz 64 MHz 112 MHz
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