Rohde & Schwarz 1145.1010.04/05/06, Operating Manual

Page: 143 / 813

R&S
®
ZVA/ZVB/ZVT Measured Quantities
1145.1084.12 3.33 E-1
Balance-unbalance conversion avoids the disadvantages of real transformers:
•
There is no need to fabricate test fixtures with integrated baluns for each type of DUT.
•
The measurement is not impaired by the non-ideal characteristics of the balun (e.g. error
tolerances, limited frequency range).
•
Calibration can be performed at the DUT's ports. If necessary (e.g. to compensate for the effect
of a test fixture), it is possible to shift the calibration plane using length offset parameters.
•
Differential and common mode parameters can be evaluated with a single test setup.
Balanced Port Configurations
Defining a logical ports requires two physical analyzer ports. The ports of an analyzer are equivalent
and can be freely combined. Moreover, it is possible to assign arbitrary, independent reference
impedance values to each unbalanced port and to the differential and common mode of each logical
port. The following types of balanced devices can be measured with 2-port, 3-port and 4-port analyzers:
2-port analyzers: Reflection measurements on 1 balanced port
3-port analyzers: Reflection and transmission measurements on 1 balanced port
4-port analyzers: Reflection and transmission measurements on 1 or 2 balanced ports
A balanced port configuration is defined by simply selecting the pairs of physical ports that are
combined to form balanced ports and defining the two reference impedances for the differential and
common mode at each balanced port. All this is done in a single dialog; refer to the help system for
details and measurement examples. The most commonly used balanced port configurations and
impedances are predefined and can be selected in the
Measurement Wizard.
Depending on the test setup, the analyzer provides different types of mixed mode parameters; refer to
the following sections for details.