There is an example in OrCad PSPICE which calculates noise figure for an RF amplifier.
I know the following formula for noise figure:
But in this example the software uses another formula:
Where V(inoise) is the equivalent input voltage noise.
I don't understand why this formula should be true and where does 8.28e-19 come from? Is it a general formula that can be used in every simulation?
and the circuit