Method for measuring spectral noise densities beyond instrument capability with deterministic confidence levels

摘要

A mechanism for measuring noise densities below the noise floor of a measuring instrument. The measuring instrument may first acquire a fully-averaged reference spectral noise density trace and estimate corresponding reference statistical parameters. Based on the reference statistical parameters, the measuring instrument may construct a reference spectral noise density distribution. The measuring instrument may also acquire a fully-averaged sum spectral noise density trace and estimate corresponding sum statistical parameters. Based on the sum statistical parameters, the measuring instrument may construct a sum spectral noise density distribution. The measuring instrument may extract a spectral noise density distribution from the reference and sum distributions. The measuring instrument may also determine a confidence interval based on a desired confidence level. The measuring instrument may then determine a desired spectral noise density measurement based on an extracted mean of the spectral noise density and the computed confidence interval.