Determining the source of phase noise: Response of a driven Duffing oscillator to low-frequency damping and resonance frequency fluctuations

We present an analytical calculation of the response a driven Duffing oscillator to low-frequency fluctuations in resonance frequency and damping. find that these parameters manifest themselves distinctively, allowing them be distinguished. In strongly nonlinear regime, amplitude phase noise due damping are attenuated, while transduction into remains order $1$. show this can seen by comparing relative strengths quadrature components, suggest provides means determine source oscillator.