The VNAuhf is
a Vector Network Analyzer for measuring impedance (magnitude and phase) and
filter transmission in the range of 5 KHz to 1 GHz.
A PC is used to plot parameters, such as: Impedance, SWR, Return Loss, S21
The test frequency is generated digitally.
An analog to digital converter digitizes the raw data. This avoids
non-linearity associated with diode detectors, and results in very good
dynamic range and linearity for accurate magnitude and phase measurements.