Rohde & Schwarz CMW-KM645 User manual

R&S®CMW-KM645
FM Stereo Radio
Firmware Applications
User Manual
User Manual
(;×ïX2)
1173.9740.02 ─ 03
Test & Measurement
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This user manual describes the following R&S®CMW options:
●R&S®CMW-KM645 (FM Stereo Radio, TX measurement)
© 2013 Rohde & Schwarz GmbH & Co. KG
Mühldorfstr. 15, 81671 München, Germany
Phone: [phone] - 0
Fax: [phone]
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®CMW is abbreviated as R&S CMW.
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Contents
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Contents
1Preface....................................................................................................5
1.1 How to Read Firmware Application Chapters............................................................5
1.1.1 General Description........................................................................................................5
1.1.2 Application Sheets..........................................................................................................5
1.1.3 GUI Reference................................................................................................................6
1.1.4 Programming Examples..................................................................................................6
1.1.5 Command Reference......................................................................................................6
2What's New in this Revision..................................................................7
3 General Description...............................................................................8
3.1 Test Setup......................................................................................................................8
3.2 Measuring an FM Signal...............................................................................................9
3.3 AF Filter Settings..........................................................................................................9
3.4 Limit Settings and Conformance Requirements......................................................10
3.4.1 RF Carrier Requirements..............................................................................................11
3.4.2 RF Modulation Requirements.......................................................................................11
3.5 Measurement Results.................................................................................................11
3.5.1 RF Carrier Results........................................................................................................11
3.5.2 RF Modulation Results..................................................................................................13
3.5.3 AF Measurement Results..............................................................................................15
3.5.4 Selecting and Modifying Views.....................................................................................17
3.5.5 Common View Elements...............................................................................................17
4GUI Reference......................................................................................19
4.1 Measurement Control.................................................................................................19
4.2 Parameters and Settings............................................................................................19
4.2.1 Signal Routing and Analyzer Settings...........................................................................20
4.2.2 Measurement Control Settings......................................................................................22
4.2.3 Limit Settings.................................................................................................................24
4.2.4 Display Settings............................................................................................................25
4.3 Measurement Results.................................................................................................26
5Programming........................................................................................28
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Contents
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5.1 Key Features................................................................................................................28
5.2 Specifying General Measurement Settings..............................................................28
5.3 Specifying Measurement Control Settings...............................................................29
5.4 Specifying Limits........................................................................................................29
5.5 Performing Single Shot RF Measurements..............................................................29
5.6 Continuous and AF Measurements...........................................................................30
6Command Reference...........................................................................32
6.1 Conventions and General Information......................................................................32
6.1.1 MEAS<i>.......................................................................................................................32
6.1.2 FETCh, READ and CALCulate Commands..................................................................32
6.1.3 Current and Statistical Results......................................................................................33
6.1.4 Reliability Indicator........................................................................................................33
6.2 Signal Routing and Analyzer Settings......................................................................35
6.3 Measurement Control and States..............................................................................39
6.4 Measurement Control Commands.............................................................................41
6.5 Limits............................................................................................................................46
6.6 Measurement Results.................................................................................................50
6.6.1 RF Carrier Results........................................................................................................50
6.6.2 RF Modulation Results..................................................................................................53
6.6.3 AF Modulation Results..................................................................................................55
List of Commands................................................................................62
Index......................................................................................................64
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Preface
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1 Preface
The operation of the R&S CMW is described in several user manuals:
●The R&S CMW user manual describes the base software, common features of the
firmware applications and basic principles for manual operation and remote control.
●Additional user manuals, like this document, describe the firmware applications.
Rohde & Schwarz provides registered users a "CMW Customer Web" section on
GLORIS, the Global Rohde & Schwarz Information System: https://extranet.rohde-
schwarz.com. From this resource you can download software updates, waveform library
updates and documentation updates, e.g. updates of this document.
1.1 How to Read Firmware Application Chapters
Each firmware application is described in a separate chapter. These chapters can be
read independently of each other. However, they are all organized as follows:
1. General Description
2. Application Sheets (optional)
3. GUI Reference
4. Programming Examples
5. Command Reference
The chapters "System Overview" and "Remote Control" in the R&S CMW user manual
provide additional important information independent of the individual firmware applica-
tions. The most important parts are referenced by the firmware application descriptions.
1.1.1 General Description
This section provides a general description of the firmware application, independent of a
specific operation mode (manual or remote control). It gives a high-level introduction to
the capabilities of the firmware application. Background information related to the network
standard is given as far as it is directly related to administrable parameters. For mea-
surement applications a detailed description of measurement results and a description
of configurable limits is given, including the relation to conformance requirements defined
in network standard specifications.
1.1.2 Application Sheets
This optional section provides short application examples for select issues and related
background information.
How to Read Firmware Application Chapters
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Preface
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1.1.3 GUI Reference
The GUI reference describes the manual operation of the firmware application via the
Graphical User Interface (GUI).
The description of a configuration dialog usually starts with a screenshot presenting the
preset values of the parameters (sometimes preset values are modified to enable hidden
parts of a dialog). Below the screenshot all shown parameters are described. For each
single parameter a link to the corresponding command description in the "Command
Reference" is provided. Ranges for numeric parameters and reset values are given there.
For measurement results links to the corresponding command descriptions are provided
(commands to retrieve the results). The measurement results are described in detail in
the "General Description".
1.1.4 Programming Examples
The programming examples show how to control and configure the firmware application
via a remote-control program and how to retrieve measurement results. The examples
consist of comprehensive command sequences. You can check just a single command
of a sequence to get an example for the syntax of this single command. But you can also
consider an entire sequence showing the commands in the context of a command script,
under consideration of dependencies and required orders of the commands.
The command sequences are written with the intention to list most commands of the
firmware application. They do not show the fastest way for a given configuration task.
The fastest way would use many reset values and omit the corresponding commands.
The examples are referenced by the command descriptions of the "Command Refer-
ence".
1.1.5 Command Reference
The command reference provides information on the remote commands of the firmware
application. The commands are grouped according to their function.
Each command description indicates the syntax of the command header and of the
parameters. For input parameters the allowed ranges, reset values and default units are
listed, for returned values the expected ranges and default units. Most commands have
a command form and a query form. Exceptions are marked by "Setting only", "Query only"
or "Event". Furthermore a link to the "Programming Examples" is provided and the first
software version supporting the command is indicated.
How to Read Firmware Application Chapters
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What's New in this Revision
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2 What's New in this Revision
This revision describes version 3.2.10 and later of the "FM Stereo Radio Measurement"
firmware application. Compared to version 3.0.10 it provides the following new features
and changes:
●Configurable frequency offset, see Frequency Offset
●Configurable mixer level offset, see Mixer Level Offset
Software Version
To check your R&S CMW software version, open the "Setup" dialog and click "HW/SW
Equipment". The initial software version for each remote control command is quoted in
the reference description.
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General Description
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3 General Description
The "FM Stereo Radio Measurement" application (option R&S CMW-KM645) provides
transmitter (TX) tests on FM-modulated RF signals (called "FM signals" in the following).
The tests cover the following FM signal properties:
●RF carrier characteristics including the carrier power, frequency error, and the fre-
quency deviation due to a composite modulating signal ("multiplex deviation")
●RF modulation characteristics including the frequency deviation due to the 19-kHz
pilot, the left and the right audio channels, and the pilot frequency error
●Characteristics of the demodulated AF baseband signal including a Total Harmonic
Distortion (THD), Signal to Noise and Distortion ratio (SINAD), and Signal to Noise
Ratio (SNR) measurement
For background information on FM signals and conformance requirements refer to the
relevant standards, e.g.:
●IEC 60315-4 (1997), Methods of measurement on radio receivers for various classes
of emission
●ITU-R Recommendation BS.450-3, Transmission standards for FM sound broad-
casting at VHF
All "FM Stereo Radio" measurements are combined in a single, multi evaluation mea-
surement group.
The following sections describe how to configure and perform the "FM Stereo Radio
Measurement".
●Test Setup.................................................................................................................8
●Measuring an FM Signal...........................................................................................9
●AF Filter Settings.......................................................................................................9
●Limit Settings and Conformance Requirements......................................................10
●Measurement Results.............................................................................................11
3.1 Test Setup
The external RF signal source (mobile station, signal generator etc.) is connected to one
of the RF input connectors (RF COM) at the front panel of the R&S CMW. No additional
cabling and no external trigger is needed.
The input level ranges of all RF COM connectors are identical.
See also: "RF Connectors" in the R&S CMW user manual, chapter "Getting Started"
Test Setup
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General Description
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Fig. 3-1: Connecting an RF transmitter to the instrument
The measurement is performed in free run mode; no trigger signal is needed.
3.2 Measuring an FM Signal
After connecting your FM signal source to the R&S CMW as shown in section Test
Setup, you have to adjust the following analyzer settings to the properties of the analyzed
signal:
●The analyzer "Frequency" (RF carrier frequency)
●The "Expected Nominal Power" and (optional) a "User Margin" and "External Attenu-
ation". Recommended values: "Expected Nominal Power" = nominal power of the RF
carrier. FM signals are transmitted at constant power (constant-envelope signals), so
the default "User Margin" of 0 dB should be sufficient.
With the settings described above, the R&S CMW is able to receive and demodulate the
FM stereo signal and obtain the essential measurement results.
The following measurements require additional settings:
●The demodulated left and right AF channel signals can be measured with different
filter settings in the AF analyzer path ("Deemphasis Filter", "Lowpass Filter", "High-
pass Filter", "Weighting Filter", "Bandpass Variable"). See section AF Filter Set-
tings.
●To determine the Total Harmonic Distortion (THD), the Signal to Noise and Distortion
Ratio (THD + N / SINAD), and the Signal to Noise Ratio (SNR), two fixed, sine wave
audio tones are transmitted over the left and right audio channels ("THD (N) Freq.
Left" and "THD (N) Freq. Right"). See description of "THD / SINAD / SNR measure-
ments" in chapter 3.5.3, "AF Measurement Results", on page 15.
3.3 AF Filter Settings
The audio receive path of the R&S CMW provides optional filter stages which affect the
AF results:
●A deemphasis filter with a time constant of either 50 μs or 75 μs. A deemphasis is
designed to decrease the magnitude of the higher frequencies with respect to the
magnitude of the lower frequencies in order to improve the overall signal-to-noise
ratio.
Measuring an FM Signal
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General Description
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A 50 μs time constant is used for FM broadcasting in Europe, North American FM
stations use a 75 μs time constant.
●An A-weighting filter defined in IEC 60651. The A-weighting filter deemphasizes the
very low and very high frequency components of the sound in a manner similar to the
frequency response of the human ear and correlates well with subjective reactions
to noise. Thus, noise levels stated in terms of dBA reflect the response of the human
ear by filtering out some of the noise in the low- and high-frequency ranges that the
ear does not detect well. The A-weighted scale commonly is used in local ordinances
and standards.
●A lowpass filter and a highpass filter with selectable cutoff frequencies. You can use
the highpass filter to eliminate a possible DC component in the audio signal that may
cause measurement inaccuracies.
●A variable bandpass filter with configurable center frequency and bandwidth.
Each of the left and right channels from the FM stereo decoder (see figure 3-7) is mea-
sured as shown below.
Fig. 3-2: Filters in the audio receive path
3.4 Limit Settings and Conformance Requirements
Conformance requirements for tests on FM signals are specified in the various standards;
the following sections give an overview.
●RF Carrier Requirements........................................................................................11
●RF Modulation Requirements.................................................................................11
Limit Settings and Conformance Requirements
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General Description
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3.4.1 RF Carrier Requirements
The RF signal consists of a carrier frequency-modulated by the composite audio signal.
According to standard IEC 62106, the modulated carrier is transmitted with a maximum
frequency deviation of ±75 kHz ("Multiplex Deviation, ± Peak / 2").
See also chapter 3.5.1, "RF Carrier Results", on page 11.
3.4.2 RF Modulation Requirements
During stereo broadcasts, the RF signal carries the left and right audio channels, used
to form the signals M and S, and the 19 kHz pilot tone. The RDS subcarrier frequency is
locked to the third harmonic of the pilot tone (57 kHz).
According to ITU-R Recommendation BS.450-3 and standard IEC 62106 (for RDS), the
following limits apply:
●The maximum "Pilot Deviation" is 8 % to 10 % of the maximum frequency deviation
of ±75 kHz.
●The RDS subcarrier deviation is from ±1.0 kHz to ±7.5 kHz. The recommended best
compromise is ±2.0 kHz
●The maximum deviation due to the M and S signals (Audio Deviation) is 90 % of the
maximum frequency deviation of ±75 kHz.
●The maximum frequency error of the pilot tone ("Pilot Frequency Error") is ±2 Hz.
See also chapter 3.5.2, "RF Modulation Results", on page 13.
3.5 Measurement Results
The results of the "FM Stereo Radio Measurement" are arranged in several groups. Use
the "Display" parameters to select the different views and to change their appearance
and contents.
●RF Carrier Results..................................................................................................11
●RF Modulation Results............................................................................................13
●AF Measurement Results........................................................................................15
●Selecting and Modifying Views...............................................................................17
●Common View Elements.........................................................................................17
3.5.1 RF Carrier Results
The "RF Carrier Results" characterize the properties of the modulated RF signal.
Measurement Results
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General Description
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Fig. 3-3: FM Stereo Radio: RF Carrier Results
The table contains the following results:
●Carrier Power: Absolute power of the RF signal in dBm. The carrier power is mea-
sured in a 500 kHz IF bandwidth.
●Carrier Freq. Error: Difference between the measured RF frequency and the
selected center frequency of the analyzer ("RF Settings > Frequency"), which is
assumed to be the rated frequency of the RF channel.
●Multiplex Deviation, ± Peak / 2: Frequency deviation of the RF signal due to the
composite multiplex signal (baseband signal, including the mono and stereo signals
and the pilot; see figure 3-8), half of the peak-to-peak value of the frequency deviation.
The multiplex deviation is measured directly after the FM demodulator, before sep-
aration of the different baseband signal contributions; see figure 3-7.
●Multiplex Deviation, + Peak: Maximum frequency deviation due to the baseband
signal relative to the rated RF frequency.
●Multiplex Deviation, – Peak: Minimum frequency deviation due to the baseband
signal relative to the rated RF frequency.
●Multiplex Deviation, RMS: RMS average of the multiplex deviation over an appro-
priate time interval (moving average). If the baseband signal consists of a single sine
wave (e.g., the pilot tone with no mono and stereo signal contributions added), the
RMS multiplex deviation corresponds to the "Multiplex Deviation, ± Peak / 2" divided
by the square root of 2.
For an unmodulated carrier, the multiplex deviation is close to zero.
As shown below the peak-to-peak frequency deviation is independent of a possible carrier
frequency error.
Fig. 3-4: Definition of peak-to peak frequency error
Measurement Results
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3.5.2 RF Modulation Results
The "RF Modulation Results" characterize the properties of the audio signal which mod-
ulates the RF carrier (baseband signal).
Fig. 3-5: FM Stereo Radio: RF Modulation Results
The table contains the following results:
●Pilot Deviation, RMS * SQRT2: Frequency deviation of the RF signal due to the 19
kHz pilot tone in the baseband signal. The pilot tone causes a harmonic frequency
deviation; therefore the RMS average times the square root of 2 provides a very
accurate estimate of the peak deviation.
●RDS Deviation: Frequency deviation of the RF signal due to the signal in the Radio
Data System (RDS) band around 57 kHz.
●Audio Left Deviation, ± Peak / 2: Frequency deviation due to the left audio channel,
half of the peak-to-peak value. See also figure 3-4.
●Audio Right Deviation, ± Peak / 2: Frequency deviation due to the right audio chan-
nel, half of the peak-to-peak value.
●Pilot Frequency Error: Frequency error of the pilot signal relative to the rated fre-
quency of 19 kHz.
FM baseband spectrum
The FM stereo baseband signal is built from two audio channels L (left) and R (right) and
a pilot tone with constant frequency.
●The "mono" audio signal is the sum of the left and right channels: M = (L + R) / 2. It
occupies the frequency range between 30 Hz and 15 kHz. In a stereo transmitter this
signal is directly fed to the FM modulator.
●The "stereo" difference signal S = (L – R) / 2 modulates a 38 kHz subcarrier using
the Double Sideband Suppressed Carrier (DSSC) AM modulation scheme. The sub-
carrier is suppressed in the transmitted FM signal.
●A 19 kHz "pilot tone" provides the frequency and phase reference for the 38 kHz
subcarrier in the transmitter. It is also used to recover the suppressed subcarrier in
the FM stereo decoder.
Measurement Results
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General Description
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Fig. 3-6: Principle of an FM stereo coder
A stereo decoder can separate the three signal contributions using appropriate filter
stages, add the (L + R) / 2 and (L – R) / 2 signals for the left channel ((L + R) / 2 + (L –
R) / 2 = L) and subtract them for the right channel ((L + R) / 2 – (L – R) / 2 = R). The
(simplified) principle of an FM stereo decoder is shown below. The diagram also shows
the different measuring points for the "RF Carrier", "RF Modulation", and "AF" measure-
ment results. To obtain the "Audio left / right deviation" results the left and right channel
signals are filtered as described in chapter 3.3, "AF Filter Settings", on page 9.
Fig. 3-7: FM stereo decoder with measuring points
Stereo signals are used for the transmission of audio programs over an FM channel. The
FM baseband spectrum also contains the Radio Data System (RDS) band around the 57
kHz RDS subcarrier and the DARC (Data Radio Channel) band around the 76 kHz DARC
subcarrier. RDS and DARC are used for data transmission. The RDS deviation is mea-
sured and displayed together with the other frequency deviation results. Apart from that,
the RDS and DARC signals will not affect any of the "RF Carrier", "RF Modulation", and
"AF" measurement results of the R&S CMW.
Measurement Results
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General Description
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The complete spectrum is shown below.
Fig. 3-8: FM baseband spectrum
3.5.3 AF Measurement Results
The "AF Results" characterize the properties of the demodulated audio signal. The results
for the left (L) and right (R) audio channels are analogous; refer to the description of the
FM baseband spectrum in section RF Modulation Results.
Fig. 3-9: FM Stereo Radio: AF Results
The "SNR Statistics" table contains the following results:
●Weighted, RMS: Frequency deviation due to the left / right audio channel measured
in the weighting filter path, RMS average over an appropriate time interval (moving
average).
●Bandpass, RMS: Frequency deviation due to the left / right audio channel measured
in the bandpass path, RMS average.
●THD: Total Harmonic Distortion; see description below. The percentage and dB
results are equivalent.
●THD + N: Total harmonic distortion and noise; see description below.
Measurement Results
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General Description
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●SINAD: Signal to Noise and Distortion ratio; the inverse of the THD + N, converted
to a dB value; see description below.
●SNR: Signal to Noise Ratio, see description below.
The filter settings for the audio measurements are described in chapter 3.3, "AF Filter
Settings", on page 9.
Max/Ext results
The results in the Max/Ext column correspond to the largest measured frequency devi-
ation and the largest distortions, e.g. the maximum THD but the smallest SINAD and
SNR.
THD / SINAD / SNR measurements
Harmonics are signals at an integer multiple of the fundamental frequency. The funda-
mental wave is the first harmonic, the n"th" harmonic is n times the frequency of the
fundamental wave. The production of harmonic frequencies by an electronic system
when a signal is applied at the input is known as harmonic distortion. The following figure
shows the fundamental wave (labeled M1) and the 2nd to 5th harmonics measured with a
spectrum analyzer.
Fig. 3-10: Harmonics spectrum
To perform a harmonics measurement, one or two fixed, sine wave audio test tones are
transmitted over the left and right audio channels. The frequency of the test tone(s) is
specified in the "Measurement Control > AF" section of the configuration dialog ("THD
(N) Freq. Left" and "THD (N) Freq. Right").
The demodulated audio signal in each of the two audio channels is the sum of three
contributions:
●Signal S: S corresponds to the power P1 of the demodulated audio signal at the
reference frequency "THD (N) Freq. Left" or "THD (N) Freq. Right".
●Distortion D: The distortion is calculated from the sum of the signal powers of the
2nd, 3rd, 4th ... harmonics:
Measurement Results
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D = P2 + P3 + P4 + ...
The R&S CMW measures up to 10 harmonics at frequencies up to 21 kHz. (Exam-
ple: with a reference frequency of 3 kHz, the distortion measurement is based on the
2nd to 7th harmonics.)
●Noise N: The noise N is the power of the noise floor.
The sum of all three contributions S + N + D is the total received audio power. S and D
can be obtained in frequency-selective measurements. To obtain the sum N + D, the
R&S CMW uses a notch filter to eliminate the fundamental wave. To avoid suppression
of the higher harmonics, the bandwidth of the notch filter is automatically adjusted to be
smaller than the reference frequency. The final results are calculated as follows:
THD [%] = sqrt (D / S) = sqrt (V22 + V32 + V42...) / V1
THD [dB] = 20 * log(THD [%]/100)
THD + N [%] = sqrt(N + D) / sqrt(S + N + D)
SINAD [dB] = 20 * log(100/(THD + N [%]))
SNR [dB] = 10 * log(S / N) = 10 * log(V12 / N)
The R&S CMW displays THD [%] values up to 100 %. A results close to 100% may
indicate incorrect settings, e.g. a specified reference frequency which if off the actual
frequency of the transmitted test tone.
3.5.4 Selecting and Modifying Views
Use the "Display" parameters to select the views and to change the appearance and
contents of the views. The following "Display" hotkeys are available:
Hotkey Description
"Select View ..." Switch to a certain detailed view or overview.
Alternatively select a diagram in the overview and press ENTER or the rotary
knob.
Use "FM > Assign Views" to disable either the RF or AF measurements.
3.5.5 Common View Elements
Below the title bar, the view shows the most important signal routing, analyzer, and input
signal settings; see chapter 4.2.1, "Signal Routing and Analyzer Settings",
on page 20.
Statistics in the result tables
Most detailed views show tables providing a statistical evaluation of results.
Measurement Results
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The statistical values in the tables are calculated as follows:
●Current: Value of the result obtained in the last measurement interval.
●Average: Average of all "Current" values referenced to the last statistics cycle.
●Max: Largest "Current" value that the R&S CMW obtained since the start of the mea-
surement.
●Min: Smallest "Current" value that the R&S CMW obtained since the start of the
measurement.
●StdDev: Standard deviation of all "Current" values since the start of the measure-
ment.
All statistical results (statistical tables and "Average" or "Max" traces) are calculated
according to the general rules for statistical results.
See also: "Statistical Results" in the R&S CMW user manual, chapter "System Overview"
Statistic Count
Progress bar for the measurement, displayed in all detailed views. During the first single
shot after the start of the measurement, the bar shows the number of elapsed measure-
ment intervals relative to the "Statistic Count". A filled progress bar indicates that the first
shot is complete and the statistical depth has been reached.
See also: "Statistical Settings" in the R&S CMW user manual, chapter "System Overview"
Out of Tolerance
Percentage of measurements that were failed because they exceeded the specified lim-
its.
Measurement Results
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GUI Reference
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4 GUI Reference
The following sections provide detailed reference information on the Graphical User
Interface (GUI) and the parameters of the "FM Stereo Radio Measurements" firmware
application.
●Measurement Control..............................................................................................19
●Parameters and Settings.........................................................................................19
●Measurement Results.............................................................................................26
4.1 Measurement Control
The measurement is turned on or off using the ON | OFF or RESTART | STOP keys.
See also: "Measurement Control" in the R&S CMW user manual, chapter "System Over-
view"
FM (Softkey)
The softkey shows the current measurement state. Additional measurement substates
may be retrieved via remote control.
Remote command:
INITiate:FMSTereo:MEAS<i>:MEValuation
STOP:FMSTereo:MEAS<i>:MEValuation
ABORt:FMSTereo:MEAS<i>:MEValuation
FETCh:FMSTereo:MEAS<i>:MEValuation:STATe?
FETCh:FMSTereo:MEAS<i>:MEValuation:STATe:ALL?
4.2 Parameters and Settings
The most important settings of the "FM Stereo Radio Multi Evaluation" measurement are
displayed in the measurement dialog.
All settings are defined via softkeys and hotkeys or using the "FM Stereo Radio Multi
Evaluation Configuration" dialog. The configuration dialog provides parameters for the
following tasks:
●Signal Routing and Analyzer Settings.....................................................................20
●Measurement Control Settings................................................................................22
●Limit Settings...........................................................................................................24
●Display Settings......................................................................................................25
Measurement Control
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GUI Reference
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20User Manual 1173.9740.02 ─ 03
4.2.1 Signal Routing and Analyzer Settings
The measurement is configured using the parameters in the "FM Stereo Radio Configu-
ration" dialog. The following parameters configure the RF input path.
See also: "Connection Control (Measurements)" in the R&S CMW user manual, chapter
"System Overview"
Fig. 4-1: FM Stereo Radio Configuration: Signal routing and analyzer settings
Scenario
Selects the measurement scenario. The measurement can be used in "Standalone"
mode, using all "FM Stereo Radio" measurement settings.
Remote command:
ROUTe:FMSTereo:MEAS<i>:SCENario?
ROUTe:FMSTereo:MEAS<i>?
RF Routing
Selects the input path for the measured RF signal, i.e. the input connector and the RX
module to be used.
Depending on your hardware configuration there may be dependencies between both
parameters. Select the RF connector first. The "Converter" parameter offers only values
compatible with the selected RF connector.
Remote command:
ROUTe:FMSTereo:MEAS<i>:SCENario:SALone
External Attenuation (Input)
Defines the value of an external attenuation (or gain, if the value is negative) in the input
path. The power readings of the R&S CMW are corrected by the external attenuation
value.
The external attenuation value is also used in the calculation of the maximum input power
that the R&S CMW can measure.
If a correction table for frequency-dependent attenuation is active for the chosen con-
nector, then the table's name and a button are displayed. Press the button to display the
table entries.
Remote command:
CONFigure:FMSTereo:MEAS<i>:RFSettings:EATTenuation
Parameters and Settings
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