Time-Domain Modelling of Phase Noise in an Oscillator

This paper presents a time-domain simulation of phase noise in a varactor-tuned voltage-controlled oscillator. Flicker, thermal and shot noise are captured using transient sources of noise based on the principles of mathematical chaos. High levels of noise are handled by replacing the ordinary differential equations used in conventional transient circuit simulation by stochastic differential equations. The system of stochastic differential equations is interpreted in the sense of Stratonovich. Simulation runs are compared with measured phase noise of the oscillator and an accurate match is found for different levels of bias