Concepts and Features
R&S
®
ZNA
213
User Manual 1178.6462.02 ─ 12
●
Like the virtual differential mode, the true differential mode requires a port configu-
ration with at least one balanced port. However, in true differential mode a bal-
anced source port requires
for the constituent physical ports.
Because a 2-port R&S
ZNA only has one source, option R&S
ZNA-K61 is not avail-
able for 2-port instruments.
●
Because true differential mode is a special kind of
,
option R&S
ZNA-K6 is a prerequisite for option R&S
ZNA-K61. The
also apply to true differential mode
5.7.5.1
Virtual vs. True Differential Mode
The analyzer uses different stimulus signals and different mathematical methods to
obtain results in normal, virtual differential, or true differential mode. The following table
gives an overview.
Normal (unbalanced)
mode
Measurement of wave quantities and S-parameters for unbalanced ports. Unbal-
anced stimulus signals.
Virtual differential
mode
Precondition: At least one balanced port is defined.
Measurement of unbalanced wave quantities using unbalanced stimulus signals.
Unbalanced system error correction. Conversion of unbalanced wave quantities
into balanced and mixed-mode S-parameters with possible renormalization of port
impedances.
True Differential
Mode
Precondition: At least one balanced port is defined, whose constituent ports are
driven by two independent sources..
Measurement of unbalanced wave quantities using balanced stimulus signals (dif-
ferential and common mode). System error correction and conversion of unbal-
anced into balanced wave quantities. Calculation of balanced and mixed-mode S-
parameters with possible renormalization of port impedances.
True Differential mode relies on wave correction. A consistent system error correction
is essential for accurate balanced waves at the reference planes and accurate mea-
surement results. You must perform a full n-port calibration (TOSM, UOSM or one of
the Txx calibration types) of all physical ports involved in the true differential measure-
ment and change the differential and common mode reference impedances, if they dif-
fer from the default settings. A subsequent source power calibration is recommended.
You can also use
Offset Parameters and De-/Embedding
ence plane where the analyzer provides an accurate differential or common mode sig-
nal.
5.7.5.2
Amplitude Imbalance and Phase Imbalance Sweep
"Amplitude Imbalance" and "Phase Imbalance" sweep types are only available in true
differential mode.
●
In an amplitude imbalance sweep, the analyzer generates a balanced signal at a
balanced logical port, but changes the power of one of the related physical ports
within a configurable power (delta) range.
Optional Extensions and Accessories
