sentences:  The conventional CIC structure is obtained by cascading formula_8 identical moving average filters, then rearranging the sections to place all integrators first (decimator) or combs first (interpolator).Such rearrangement is possible because both combs and integrators are LTI.For an interpolator, the upsampler which normally precedes the interpolation filter can be passed through the comb sections using a Noble identity, reducing the number of delay elements needed by a factor of formula_9.