Simulation and modeling of phase noise in open-loop oscillators

This paper presents a discussion about the definition of phase noise for general oscillation waveforms; a numerical method for transistor-level simulation and characterization of phase noise in open-loop (free running) oscillators; application of the phase noise simulation method to harmonic, relaxation and ring oscillators and a technical discussion of the phase noise characterization results; comparisons of the results of phase noise simulations for harmonic, relaxation and ring oscillators with the results of related work in the literature.