R&S® ZVAX24
Pulse Profile Measurements
Application Sheet
1ZKD-14, M. Jetter, 06/2009 ─ 02
Application Sheet
Test & Measurement
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Phone: +49 89 41 29 - 0
Fax: +49 89 41 29 12 164
E-mail: info@rohde-schwarz.com
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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 guide: R&S® ZVAX24 is abbreviated as R&S ZVAX24. Options R&S® ZVAX-
Bxxx are abbreviated as R&S ZVAX-Bxxx. The vector network analyzer R&S® ZVA24 is abbreviated as R&S ZVA24.
R&S® ZVAX24
1 Pulse Profile Measurement
Pulse Profile Measurement
Required Equipment
This application sheet describes the use of an R&S ZVA vector analyzer and an
R&S ZVAX24 extension unit for creating a pulsed RF signal and performing pulse profile measurements.
1.1 Required Equipment
The pulse profile measurement can be carried out with the following equipment:
● Network analyzer (NWA) R&S ZVA24 with a firmware version V2.60 or higher and
a motherboard part number 1305.6470.02 (see "Info > Hardware Info ...")
● Option R&S ZVA-K27, "Pulse Generator"
● Option R&S ZVA-K7, "Pulsed Measurements"
● Option R&S ZVA24-B16, "Direct Generator/Receiver Access" at source port 1
● One R&S ZVAX24 extension unit equipped with option R&S ZVAX24-B271, "Pulse
Modulator Generator Port 1"
1.2 Measurement Principle
The pulse modulator option R&S ZVAX24-B271 provides a pulsed source signal at the
NWA port 1. Pulse width and period are determined by the used pulse generator,
which can e.g. be the internal pulse generator of the NWA provided by option
R&S ZVA-B27. This option also provides a second "Sync" signal that can be used to
synchronize the measurement to the rising edge of the generated pulses.
The DUT is connected between the test ports 1 and 2 of the analyzer; the transmitted
pulsed signal is measured at port 2 using the analyzer's "Pulse Profile" mode.
The measurement involves the following steps:
1. Connecting the extension unit
2. Configuring the extension unit for the selected measurement and test setup
("ZVAX Path Configuration")
3. Defining the pulse generator and the trigger settings
4. Configuring the "Pulse Profile" mode
5. Calibration
6. Connecting the DUT and measuring
Power calibrations and system error corrections for test setups with an extension unit
can be performed in the ordinary way.
3Application Sheet 1ZKD-14, M. Jetter, 06/2009 ─ 02
R&S® ZVAX24
Pulse Profile Measurement
Connecting the Extension Unit
1.3 Connecting the Extension Unit
The pulse profile measurement requires the following connections between the network analyzer and the extension unit.
RF connection: Connect SOURCE IN (ZVAX) to SOURCE OUT (NWA) and
●
SOURCE OUT (ZVAX) to SOURCE IN (NWA).
Control connection: Connect USB FROM NWA (ZVAX) to any of the USB type A
●
connectors at the front or rear panel of the NWA.
Pulse generator connection: Connect CASCADE IN (ZVAX) to CASCADE (NWA)
●
using the RJ-45 cable supplied with the extension unit.
The DUT is connected between the analyzer ports 1 and 2. The schematic test setup is
shown below.
Fig. 1-1: Test setup for pulse profile measurement
1.4 ZVAX Path Configuration
When the extension unit is connected to the network analyzer as described before, it is
possible to select the modules to be looped into the signal path(s) and the routing of
4Application Sheet 1ZKD-14, M. Jetter, 06/2009 ─ 02
R&S® ZVAX24
Pulse Profile Measurement
ZVAX Path Configuration
the pulse generator signals. This is done in the "ZVAX Path Configuration" dialog
("Channel > Mode > ZVAX Path Configuration"). The schematic in this dialog shows all
RF modules installed in the extension unit.
The dialog below corresponds to a fully equipped extension unit. The source signal
path for port 1 corresponds to the highlighted section in the center.
Fig. 1-2: ZVAX Path Configuration
1. Use the radio buttons in the "ZVAX Path Configuration" dialog to activate the "Src 1
Pulse Modulator". If your extension unit contains a harmonic filter or combiner,
select the corresponding through paths.
2. Click "Pulse Generators" and make sure the "Modulator Source" and "Modulator
Assignment" settings are as shown below.
5Application Sheet 1ZKD-14, M. Jetter, 06/2009 ─ 02
R&S® ZVAX24
Pulse Profile Measurement
Pulse Generator Signals
Fig. 1-3: Pulse Generator settings
1.5 Pulse Generator Signals
The pulse generator provides single pulses with defined width and period or sequences of pulses (pulse trains). In the example below, a single pulse with a width of 1.4 μs
is generated. The pulse is repeated after a pulse period of 5 μs. The second pulse generator signal ("Sync" signal) can be used to synchronize data acquisition to the pulse.
6Application Sheet 1ZKD-14, M. Jetter, 06/2009 ─ 02
R&S® ZVAX24
Pulse Profile Measurement
Pulse Generator Signals
Fig. 1-4: Define Pulse Generator
1. Click "Channel > Sweep > Sweep Type > Pulse Generator" to activate the pulse
generator signal.
2. Click "Def Pulse Generator..." and configure the "Pulse Parameters" as shown
above.
3. In the "Define Pulse Generator" dialog, click "Define Sync Generator..." and ensure
that the "Sync" signal is configured as shown below.
Fig. 1-5: Define Sync Generator
4. Click "Channel > Sweep > Trigger > Pulse Gen..." to select the pulse generator as
trigger source.
The dialog "Pulse Gen Trigger" opens. Close it without modifying the default setting
("Rising Edge Sync").
7Application Sheet 1ZKD-14, M. Jetter, 06/2009 ─ 02
R&S® ZVAX24
Pulse Profile Measurement
Pulse Profile Mode
1.6 Pulse Profile Mode
The pulse profile mode of the network analyzer is particularly suited for measurements
on pulsed signals. The parameters must be adjusted to the pulse generator settings. In
the example below, the start and stop time have been adjusted to view the 1.4 μs pulse
width defined previously.
Fig. 1-6: Define Pulse Profile
1. Click "Channel > Sweep > Sweep Type > Pulse Profile" to activate the pulse profile
mode.
2. Click "Define Pulse Profile..." and configure the "Time Parameters" as shown
above.
The R&S ZVA help system provides detailed information about the pulse profile mode
including measurement examples.
1.7 Calibration
The source signal from port 1 is attenuated on its way through the R&S ZVAX24 extension unit. The unit stores a number of power correction data sets to account for the
effects of the different modules and signal paths in the extension unit. Whenever a new
R&S ZVAX24 configuration is defined the analyzer modifies its own factory power correction data using the appropriate data set from the unit (see chapter 1.4, "ZVAX Path
Configuration", on page 4).
The active modified factory power correction data set is replaced when the user performs his own power calibration. Power calibrations and system error corrections for
test setups with an extension unit can be made in the ordinary way.
1.8 Measurement
After power calibration and system error correction, the pulsed measurement can be
performed as outlined in chapter 1.6, "Pulse Profile Mode", on page 8. All measured
8Application Sheet 1ZKD-14, M. Jetter, 06/2009 ─ 02
R&S® ZVAX24
Pulse Profile Measurement
Possible Extensions
quantities (S-parameters, wave quantities, ratios etc.) and other trace settings are
available.
The following example shows the reflected wave a1, the transmitted wave b2, and the
forward transmission coefficient S21 of a DUT with the settings of the previous sections.
Fig. 1-7: Example for pulse profile measurement
It can be seen that the steepness of the edges of the S21 pulse arises from ratioing
(b/a) and does not provide a measure for the rise and fall times of the pulse itself.
1.9 Possible Extensions
The extension unit R&S ZVAX24 can accommodate up to three pulse modulators (for
two source paths and a receiver path) plus a variety of other hardware options. Options
installed internally are shown in the "ZVAX Path Configuration" dialog (figure 1-3). An
arbitrary combination of options may be used simultaneously.
1.10 Additional Information
For a comprehensive description of the measurement dialogs related to the
R&S ZVAX24 including remote control refer to the R&S ZVA online help system or to
9Application Sheet 1ZKD-14, M. Jetter, 06/2009 ─ 02
R&S® ZVAX24
Pulse Profile Measurement
Additional Information
the printable operating manual, which is available for download at http://www.rohde-
schwarz.com/product/zva.
For an description of the R&S ZVAX24 connectors and safety instructions refer to the
R&S ZVAX24 Quick Start Guide.
10Application Sheet 1ZKD-14, M. Jetter, 06/2009 ─ 02
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