Figure 1 shows the block diagram of a simplified model of eye-movement control. J represents the moment of inertia of the eyeball about the axis of rotation, while B represents the viscous damping associated with the rotational movement of the eye. The target angular position of the eye, ref, is set by the higher centers. G is a gain that converts the controlling signal into the torque exerted by the extraocular muscles. Information about the angular position of the eye, O, is fed back to the controller with unity gain. Velocity information is also fed back with variable gain, K, (>0). Deduce expressions for the responses of this system to a unit step change inef when: (a) there is no feedback at all; (b) there is only position feedback (Ky = 0); (c) both position and velocity feedback exist. Figure 1 k, Oref 1 1/s Js + B