Compensation of an error-sampled system by a multirate controller

A special type of multirate sampled-data system, i.e., a system which contains switches operating with different sampling periods, is discussed in this paper. It is shown, after a brief outline of the multirate mathematics, how a multirate controller can be designed to compensate an error-sampled feedback system. Such a controller can be realized as a pulsed network which in response to input samples at time t = 0, T, 2T, ¿ produces output samples at time t = 0, T/n, 2T/n, ¿ (where n is an integer), any output sample being a linear combination of the past and present inputs and outputs. The multirate controller achieves a lower intersampling ripple and a faster settling time in comparison with its single-rate predecessor at no increase, in most cases, in the number of the required storage elements.