https://www.ni.com/en/support/documentation/supplemental/06/using-the-pxi-2593-50-ohm-rf-switch-in-a-75-ohm-configuration.html
Using the PXI-2593 50 Ohm RF Switch in a 75 Ohm Configuration - NI
In a perfect world, the signal from a source would be delivered to a load without any losses. In reality, to reduce losses, impendence should be matched...
50 ohm rf
https://www.tek.com/de/keithley-switching-and-data-acquisition-systems/keithley-daq6510-manual/model-7711-2-ghz-50-ohm-rf
Model 7711 2 GHz 50 Ohm RF Module Instructions for use with DAQ6510 | Tektronix
Includes instructions for wiring, installing, removing, operating, and verifying performance of the 7711 switching module.