Some considerations on coefficient sensitivity and noise in direct form IIR interpolators and decimators

Direct form implementation of IIR filters for sample rate alteration has been shown (1) to be efficient when the recursive part of the filters work at the low sampling frequency. In this paper we suqgest to generalize the IIR interpolators/decimators by introducting partial zero-forming of their passband. A design method based on the Reméz exchange algorithm is proposed. The advantage of these filters is that the coefficient sensitivity as well as the quantization noise can be reduced. An illustrative design example is presented.