Time-domain simulation and spectrum measurement of low-noise oscillators

This paper deals with the modeling of noise spectra in high Q-factor oscillators so as to better understand the noise mechanism and to improve the low noise oscillator design. The dipolar method used is first demonstrated on a simple behavioral oscillator. Noise analysis consists in calculating the and the transient response in the vicinity of the steady state with asymptotic methods. Then, the oscillator noise is calculated by introducing a small sinusoidal perturbation to the steady state. This allows to analyze both additive and parametric noise. The model provides time-domain waveforms, AM and PM noise spectra, and analytically explains the Leeson model.