Beware the three-way arbiter
Beware the three-way arbiter
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小心三路仲裁者
DOI：
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发表时间：
1999
期刊：
影响因子：
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通讯作者：
C. E. Molnar
中科院分区：
文献类型：
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作者：
K. V. Berkel;C. E. Molnar
用于三路仲裁器的对称电路可基于三触发器，即三个三输入NAND门的交叉耦合结构。这个仲裁器有七个亚稳态，其中六个是二进制和一个三进制。取决于电路中可能的不对称性，偏离三元亚稳态可能是呈指数增加的振荡的形式。这样的振荡可能在仲裁器的输出处表现为尖峰，并且因此是潜在危险的。详细的小信号分析周围的三值亚稳态的三触发器显示这些振荡的频率和幅度取决于电路参数。该分析还建议如何实现可靠的三路仲裁器，即使在基本标准单元方面也要谨慎。三路仲裁器可以简单地修改为三取二仲裁器。
A symmetric circuit for a three-way arbiter can be based on a triflop, a cross-coupled structure of three three-input NAND gates. This arbiter has seven metastable states, of which six are binary and one ternary. Depending on possible asymmetries in the circuit, departure from the ternary metastable state may be in the form of exponentially increasing oscillations. Such oscillations may appear as spikes at the outputs of the arbiter and are therefore potentially hazardous. A detailed small signal analysis around the ternary metastable state of the triflop shows how the frequency and magnitude of these oscillations depend on circuit parameters. This analysis also suggests how to implement a reliable three-way arbiter, even, with some caution, in terms of basic standard cells. The three-way arbiter can simply be modified into a two-out-of-three arbiter.