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Metastability in electronics is the ability of a digital electronic system to persist for an unbounded time in an unstable equilibrium or metastable state.〔 〕 In metastable states, the circuit may be unable to settle into a stable '0' or '1' logic level within the time required for proper circuit operation. As a result, the circuit can act in unpredictable ways, and may lead to a system failure, sometimes referred to as a "glitch".〔(【引用サイトリンク】first=Thomas J. )〕 Metastable states are inherent features of asynchronous digital systems, and of systems with more than one independent clock domain. In self-timed asynchronous systems, arbiters are designed to allow the system to proceed only after the metastability has resolved, so the metastability is a normal condition, not an error condition.〔 〕 In synchronous systems with asynchronous inputs, synchronizers are designed to make the probability of a synchronization failure acceptably small.〔(【引用サイトリンク】first=Thomas J. )Washington University St. Louis, MO〕 Metastable states are avoidable in fully synchronous systems when the input setup and hold time requirements on flip-flops are satisfied. == Arbiters == (詳細はsynchronizers for input signals. Although they can minimize the occurrence of metastability to very low probabilities, all arbiters nevertheless have metastable states, which are unavoidable at the boundaries of regions of the input state space resulting in different outputs.〔 〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Metastability in electronics」の詳細全文を読む スポンサード リンク
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