When To Change The System Impedance - HP 8712ES User Manual

Making Measurements
Measuring Devices with Your Network Analyzer

When to Change the System Impedance

Your analyzer has a system characteristic impedance of either 50 or 75
ohms, yet may be changed to the alternate impedance. If using
minimum-loss pads for impedance conversions, the alternate impedance
should be selected so that the measurement results are displayed
relative to the conversion impedance.
For example, if you have a 50 ohm instrument and are making 75 ohm
measurements, you may be using 50 to 75 ohm minimum-loss pads.
Measurement results can be reported relative to 75 ohms, not 50 ohms, if
the alternate system impedance is selected. This includes marker
readouts, Smith chart results, or SRL impedance computations
(Option 100).
To change the system impedance, press the following keys on the
analyzer:
CAL
More Cal
System Z0
50 Ω οr 75 Ω
The built-in cal kit selections will be converted to the selected system
impedance.
3-12 ES User's Guide