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**Advances in asynchronous circuit theory. I: Gate and unbounded inertial delay models.**
*(English)*
Zbl 0747.94023

Summary: Although the theory of asynchronous circuits dates back to the early 1950s, considerable progress has been made in this area in the past five years. This paper constitutes the first part of a two-part survey of the recent advances in this field. Part I of the survey presents a unified and concise overview of those aspects of the theory that deal with the behavior of circuits under the assumption that delays in the circuit components and wires are unbounded. The historical development of the subject is presented, and some shortcomings of the earlier approaches are discussed. Ternary simulation is related to the binary analysis methods; the ternary approach is then used to correct the flaws in the earlier work. The question of realizability of sequential behaviors is then considered. It is shown that the class of realizable behaviors is rather severely restricted by the unbounded-delay assumption and that the use of bounded-delay models is more realistic. Part II of the survey will deal with bounded-delay models, MOS circuits, classical and delay-insensitive design methods, and complexity issues.

### MSC:

94C10 | Switching theory, application of Boolean algebra; Boolean functions (MSC2010) |

94-02 | Research exposition (monographs, survey articles) pertaining to information and communication theory |