Reduction of augmentation order in pipelined realization of IIR filters by cascade/parallel form

In pipelining an IIR filter, a look-ahead transformation is applied to the system transfer function in order to obtain delay units in the feedback loop and consequently create cutsets along the pipeline path. A drawback is that look-ahead transformation increases the number of filter coefficients. In this paper, we investigate order augmentation due to the cluster look-ahead transformation in pipelined direct form IIR filter. We show that the order augmentation can be reduced using cascade form or parallel form.