Uncertainty Analysis for Noise-Parameter Measurements at NIST

An uncertainty analysis is presented for the National Institute of Standards and Technology (NIST) measurements of the noise parameters of amplifiers and transistors in both connectorized (coaxial) and on-wafer environments. We treat both the X-parameters, which are based on the wave representation of the noise correlation matrix, and the traditional IEEE noise parameters. The type A uncertainties are obtained from the fit that computes the noise parameters from an overdetermined system of equations, and the type B uncertainties are computed by a Monte Carlo program. Some complications that are explicitly discussed include the effect of an output attenuator or probe, physical bounds, and the occurrence of unphysical results. Some sample results are given.