FAQ

For a device under test (DUT), noise figure is a measure of signal-to-noise ratio degradation due to the DUT. Noise figure depends on the output impedance of whatever circuit is driving the DUT. To know how much noise figure changes when the driving port impedance changes, one needs to know the DUT noise parameters. Noise parameters give a complete picture of noise behavior of the DUT. They can be used to determine noise figure, but they can also be used to determine the best possible noise figure achievable with the DUT and the optimum matching to achieve it. Some more information on noise parameters is available at https://www.microwaves101.com/encyclopedias/noise-parameter-equations.