An eigenvalue study of a double integrator oscillator

A tutorial study of an oscillator built from a loop of two active RC integrators and an ideal inverter. As a reference the linear harmonic oscillator is modeled as a LC circuit and as an ideal two integrator loop. The nonlinear amplifiers of the active RC integrator circuits are assumed to be linear with time varying gain and the eigenvalues are found as function of time. A design strategy based on the time-constants of the integrators is presented.