Agilent Technologies E5071C Manual page 470

In the terminology of the E5071C, ports after the balance conversion are
called logical ports (or DUT ports).
You can freely assign the test ports of the E5071C to logical ports (ports a
to d in the figure above).
Measurement Parameters of Balanced Devices
Turn on the balance-unbalance conversion function to measure the
following parameters.
Mixed mode S-parameter
•
Imbalance parameter
•
CMRR (Common Mode Rejection Ratio)
•
Mixed mode S-parameter
By turning on the balance-unbalance conversion function, you can obtain
the S-parameter of the balanced port separately for two modes, the
differential mode and the common mode. The following figure shows the
notation of the S-parameter in balance measurement (mixed mode S-
parameter).
Notation of mixed mode S-parameter
Measurement
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