Concepts and Features
R&S
®
ZNC
53
User Manual 1173.9557.02 ─ 13
Unbalance-balance 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.
3.3.5.1
Balanced Port Configurations
Defining a logical port requires two physical analyzer ports. The ports of an analyzer are
equivalent and can be freely combined. Moreover, it is possible to assign arbitrary, inde-
pendent 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
Bal.
port
Differential mode
Z
ref
= Z
0d
Common mode
Z
ref
= Z
0c
DUT
Balanced port:
Log.
VNA
port
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
"Balanced Ports" dialog. 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 param-
eters; refer to the following sections for details.
Measurement Results
