Unfolding and retiming for high-level DSP synthesis

A method of determining the minimum unfolding factor needed to synthesize a data path for a given sample rate is presented. Minimizing the unfolding factor is important because the time complexity for scheduling and allocation increases linearly with the unfolding factor. The authors discuss the iterative algorithm which calculates the minimum unfolding factor necessary to achieve a given sample rate with and without retiming. This algorithm is utilized within the MARS (the Minnesota architecture synthesis) design system to preprocess a dataflow graph prior to resource scheduling and allocation