The PNA Series frequency offset capability (Option 080) enables the network analyzers to set the source frequency independently from where the receivers are tuned. This ability is important for two general classes of devices: mixers (and converters) and amplifiers.
Option 081 adds a solid-state internal RF transfer switch in the R1 reference-receiver path. This switch allows the instrument to easily switch between standard S-parameter measurements and frequency offset measurements such as relative phase or absolute group delay that require an external reference mixer. The user can set the switch manually or remotely, but it is best used with the frequency-converter application (Option 083), where it is controlled automatically during the vector-mixer calibration procedure and subsequent measurements.