Synthesis of asynchronous sequential circuits with minimum number of delay elements

In this paper, we present a procedure for realizing any normal mode flow table by an asynchronous sequential circuit with a single pure delay, so that no hazards are present even if several input variables change in a transition. A modification of Unger´s single delay realization is also proposed in order to allow several inputs to change in a transition without producing output transients. We also show how any normal mode flow table can be realized without inserted delay elements if a restriction on the relative magnitudes of line and gate delays is satisfied and only one input variable is allowed to change in a transition.