Abstract: State reduction of the completely specified sequential logic circuit refers to find and combine the equivalent states in the logic circuit.The reduction can simplify the circuit,improve its safety and decrease its hardware cost at the same time.The key point for state reduction is to find the maximal state equivalence classes.In this paper,an equivalence relation based algorithm was proposed by introducing granular computing method.By defining output matrix,sub-state matrix,and marking the initial states in the matrices,the initial state mark matrix and the sub-state mark matrix were obtained.Then,state transition system matrix was constructed,and the the initial states in the state table was continuously partitioned from coarser granularity to finer granularity until the maximal state equivalence classes were obtained.The experimental results and complexity analysis show the accuracy and efficiency of the proposed algorithm.

Key words: State reduction,Equivalence relation,Granular computing,Sequential logic circuits