System Overview
R&S
®
ZVT
76
Getting Started 1300.0045.62 ─ 10
To perform balanced measurements, a pair of physical analyzer ports is combined to
form a logical port. The balanced port of the DUT is directly connected to the analyzer
ports
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.
3.3.2.12
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 differen-
tial 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.
NWA
port
3-port analyzers: Reflection and transmission measurements on 1 balanced port
Measured Quantities
