VNA Concepts and Features
R&S
®
ZNL/ZNLE
257
User Manual 1178.5966.02 ─ 07
Safety aspects
●
The calibration unit is intended for direct connection to R&S
ZNL/ZNLE network
analyzers following the procedure described above. You can also connect the unit
before switching on the analyzer. Do not connect the unit to other USB hosts, e.g.
a PC, or insert any USB hubs between the analyzer and the unit, as this may dam-
agethe unit or the host.
●
You can connect several calibration units to the different USB ports of the analyzer.
You can also connect cal units and other devices (mouse, USB memory stick etc.)
simultaneously.
●
An unused calibration unit may remain connected to the USB port while the net-
work analyzer is performing measurements. It must be disconnected during a firm-
ware update.
●
It is safe to connect or disconnect the calibration unit while the network analyzer is
operating. Never connect or disconnect the unit while data is being transferred
between the analyzer and the unit. Never connect the unit during a firmware
update.
8.5.5.2
Performing an Automatic Calibration
After connection and initialization of the calibration unit, perform the automatic calibra-
tion of the related test ports using the "Calibration Unit" wizard ([Cal] > "Start... (Cal
Unit)"; see
Chapter 9.12.1.3, "Calibration Unit Wizard"
on page 440). The wizard indi-
cates the required port (re-)connections.
The assignment between the analyzer ports and the cal unit ports can be detected
automatically. If auto-detection fails (e.g. because of a high attenuation in the signal
path), you can either enter the port assignment manually or connect matching port
numbers and select "Default Port Assignment".
When finished, remove the test cables from the unit, connect your DUT instead and
perform calibrated measurements.
Accuracy considerations
To ensure an accurate calibration, please observe the following items:
●
Unused ports of the calibration unit must be terminated with a 50
Ω match.
●
No adapters must be inserted between the calibration unit and the test ports of the
analyzer.
●
Allow for a sufficient warm-up time before starting the calibration. Refer to the
specifications of the calibration unit for details.
●
To ensure best accuracy, the analyzer automatically reduces the source power to
-10
dBm. If the test setup contains a large attenuation, deactivate "Auto Power
Reduction for Cal Unit" in the "Calibration" tab of the VNA Setup dialog. Ensure an
input power of -10
dBm at the ports of the calibration unit (please also refer to the
specifications of the calibration unit).
Calibration
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Allice Messtechnik GmbH
