Realization of a class of compensators by modulated-demodulated structures with application in tracking of biased sinusoids

We derive conditions under which a modulated-demodulated control system is equivalent to a linear-time-invariant (LTI) transfer function. A design strategy is proposed to realize any LTI compensator with non-repeated complex poles by a modulated-demodulated structure. We also propose two different approaches for tracking of biased sinusoidal reference signals in a modulated-demodulated control system. Tracking and disturbance rejection performances of the proposed methods are evaluated and compared by simulations performed on a non-minimum-phase marginally stable plant.