Noise source modeling for cyclostationary noise analysis in large-signal device operation

Starting from the analysis of fundamental noise sources in large-signal (LS) periodic operation, a system theory approach is proposed for the modeling of colored noise sources in devices and circuits driven in LS conditions. According to this interpretation, colored sources are generated by low-pass filtering and amplitude modulation of a white unit Gaussian process. The order of the modulation and filtering steps leads to two different (albeit coincident in small-signal conditions) LS noise sources. Through the analysis of GR noise in physics-based device simulation, it is shown that only one modulation scheme (based on low-pass filtering followed by amplitude modulation) is consistent with the fundamental approach. This result also applies to 1 / f noise mechanisms when 1 / f fluctuations derive from population fluctuations.