R&S ZNB Series User Manual page 128

®
R&S ZNB/ZNBT
Redefining physical ports can be used to insert external components (e.g. external sig-
nal separating devices, power amplifiers etc.) into the signal path. This allows you to
develop custom measurements, e.g. to test high-power devices and extend the
dynamic range.
Figure 4-6: Redefined physical port 1 (port 2 not used)
Figure 4-7: Two redefined ports
High Signal Power
When dealing with external signal amplification, make sure that:
●
the signals fed to the analyzer are within the allowed range
●
during calibration the calibration standards meet the requirements in terms of their
power handling capacity
Attenuator pads can be used to adapt the power levels.
4.3.2 Reference impedances
Changing the reference impedances of the analyzer ports is often referred to as
renormalization of port impedances. Renormalization means that the measurement
results measured at 50 Ω (75 Ω) are converted into results at arbitrary port impedance.
●
Renormalization of the physical port impedances affects, e.g., S-parameters and
wave quantities in "Power" representation.
User Manual 1173.9163.02 ─ 62
Ext
VNA
Gen 1
1
Dual
Amp
Directional Coupler
VNA
1 2 3
Amp
coupler
Redefined Physical Port 1
a wave: b
1
b wave: b
2
Source: Ext Gen 1
2
DUT
Redefined Physical Port 1
a wave: b
2
b wave: b
3
Source: Port 1
4
Redefined Physical Port 2
a wave: a
4
b wave: b
4
Source: Port 4
DUT
Concepts and features
Measurement results
128