HP 8712ES User Manual page 134

Making Measurements
Measuring Impedance Magnitude
cannot correct for load match errors, the results of the transmission
transform are less accurate than the reflection transform. To minimize
these errors, a good load match is recommended. One way to achieve this
is to use an attenuator on the load side of the device, as shown in
Figure 3-38. If you choose to do this, be sure to connect the attenuator
before performing the enhanced response calibration.
When interpreting the resulting impedance measurement, remember
that the analyzer is computing a transform and displaying the
equivalent series impedance. If your device has significant shunt
impedance, the results may differ significantly from the expected series
impedance.
Figure 3-38 Equipment Setup for a Transmission Measurement of Impedance
Magnitude
3-82 ES User's Guide