Accuracy and repeatability of noise measurements with a discrete Fourier transform

Noise and signal-to-noise measurements are often made using sampled signals and discrete Fourier transforms. In addition to the sampling and circular spectrum issues associated with making an accurate measurement, it is important to understand how accurate and repeatable the measurement is. This work provides an analysis of the expected accuracy of a spectral noise measurement and a method to determine the accuracy for a generic measurement system. Simulation results and experimental data are provided to support the analysis.