A method for reducing an effect of a disturbance signal on an output of a
dynamic system. The method includes generating an increment of the
disturbance signal, and modifying an incremental signal input to the
dynamic system based on the increment of the disturbance signal, thereby
reducing the effect of the disturbance signal. According to one
embodiment the method includes generating an increment by calculating a
difference between two values sampled during consecutive sampling
periods, wherein a first one of the two values is sampled during a first
one of the consecutive sampling periods, and wherein a second one of the
two values is sampled during a second one of the consecutive sampling
periods, and wherein the two values are disturbances.