The cost of limit-cycle elimination in IIR digital filters using multiplier blocks

Multiplier blocks significantly reduce the cost of multiplication in digital filters, especially in structures that allow large numbers of products of a single multiplicand. Some such structures, the direct form and cascaded second-order sections, have previously been shown to be less costly than the wave structure. In this paper, the effects of eliminating zero-input limit-cycles (LC), hereinafter called simply “limit-cycles”, from these structures is examined. The direct form no longer competes with the wave structure, but the cascade structure is still found to be the most cost-efficient