★ We propose a parametric model of the phase noise of the BAW devices on the idea that resonator parameters are noise sources. ★ An equivalent resonator model with fluctuating parameters is solved with the averaging method. ★ The result is the nonlinear system with fluctuating coefficients for amplitude and phase of the output signal. ★ The numerical simulations correspond to all recent measurements of the quartz resonator phase noise. ★ The proposed model is compared with the simplified phase-space approach and noise conversion method.
Excepted for the very short terms the frequency stability of ultra-stable oscillators is mainly limited by the resonator noise. In this work we proposed a parametric model of the bulk acoustic wave (BAW) resonator phase noise based on an equivalent circuit. This model explains phase noise generated by a BAW crystal from a point of view of parametric fluctuations and proves the f−1 dependences of the crystal noise. The model performance is verified with simulation. Simulation results are compared to experimental data and discussed. Comparison of three existing models is made.