Figure 2.

Clocking scheme. The clock cycle governing the pipeline transmission through a QCA. It is based on four phases, switch [0, ), hold [), release [), and relax [, 1). Indices 0–3 indicate the clock zones, governed by a phase shifted original clock signal C₀, so that when a cell in clock zone 0 is in the hold phase, a cell in clock zone 1 is in the switch phase, a cell in clock zone 2 is in the relax phase, and a cell in clock zone 3 is in the release phase.