GUI Reference
R&S
®
ZNB/ZNBT
444
User Manual 1173.9163.02 ─ 38
Figure 5-43: Reference Impedance Tab (>4 physical ports)
The default reference impedance for a physical port is equal to the reference impe-
dance of the connector type assigned to the port but can be defined as an arbitrary
complex value (renormalization of port impedances). By changing the reference impe-
dance, it is possible to convert the measured values at 50 Ω (75 Ω) into values at arbi-
trary port impedances.
For balanced ports it is possible to define separate complex reference impedances for
differential and for common mode.
Balanced
port
Single-
ended port
Differential mode
Z
ref
= Z
0d
Common mode
Z
ref
= Z
0c
DUT
Single-ended
(unbalanced) port
Z
ref, default
= Z
connector
2
3
}
1
2
Physical Port
no.
Logical Port
no.
Analyzer
1
Balanced port:
Single Ended Mode / Common Mode / Differential Mode
Defines arbitrary reference impedances.
"Single Ended Mode" is available for single-ended logical ports only, "Common Mode"
and "Differential Mode" impedances for balanced ports only.
The default values for the balanced port reference impedances are derived from the
(real) default reference impedance Z
0
= 50 Ω of the (single-ended) physical analyzer
ports:
●
The default value for the differential mode is Z
0d
= 100 Ω = 2*Z
0
.
●
The default value for the common mode is Z
0c
= 25 Ω = Z
0
/2.
Meas Softtool
