传统的概率转移矩阵（PTM）方法是一种用于估计软错误对组合电路可靠度影响的有效方法，但传统PTM方法只适用于组合逻辑电路的可靠度评估．触发器是时序逻辑电路的重要组成部分，其可靠度评估对时序电路的可靠度分析研究至关重要．为此，本文提出了基于PTM的触发器可靠度计算的F-PTM方法及电路PTM的判定定理．F-PTM方法首先建立触发器电路的特征方程，再用电路PTM的判定定理生成触发器的PTM，最后，根据输入信号的概率分布函数计算出电路的可靠度．与传统PTM方法相比较，F-PTM方法既能计算组合电路的PTM，又能计算触发器电路的PTM，其通用性强．对典型的触发器电路和74X系列电路中的触发器电路的实验结果表明，F-PTM方法合理可行．与多阶段方法和Monte Carlo方法的实验结果相比较，F-PTM方法得到的结果更精确．%The traditional method based on probabilistic transfer matrices (PTM)enables accurate evaluation of relia-bility for moderately large combinational circuits,but it can only be applied to combinational circuits.Flip-flop is an impor-tant component of sequential circuits,and its reliability estimation is essential for reliability analysis of sequential circuits. Therefore,a general computational framework for reliability estimation of flip-flops based on PTM (F-PTM)and a decision theorem of circuit’s PTM are proposed.Firstly,a logical function of the flip-flop circuit is expressed;and then its PTM is calculated by deduction employing the proposed decision theorem;finally,the circuit’s reliability is estimated by probability distribution of its inputs.Compared with the traditional PTM method,the F-PTM method can calculate PTMs for both com-binational circuits and flip-flop circuits.Experimental results of the classical flip-flop circuits and 74X series circuits show that the F-PTM method is efficient and feasible.The comparison of our method with multiple-pass method and Monte Carlo simulation also demonstrate that the reliability results estimated by the F-PTM method is more accurate.
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