A generalized method for computing oscillator phase noise spectra

This paper presents a generalized semi-analytic method for computing oscillator phase noise spectra, including the details very close to the oscillation frequency. The starting point is a general relation between an oscillator´s output power spectral density and the characteristics of the input noise processes. For weak input noise processes that vary sufficiently fast over time, this relation reduces to an analytic expression. For cases that do not satisfy these conditions, the relation is, in part, evaluated numerically. This is accomplished using techniques for exponential data fitting. The resulting method is able to compute oscillator phase noise spectra for a wide range of input noise characteristics.