A design for a minimum Hamming-distance search using asynchronous digital techniques

An approach for a completely static and digital implementation of a minimum Hamming-distance search is presented in this paper. A newly developed associative memory performs the search operation by executing a bubble sort operation for a binary data, which we call a bubble shift, with the assistance of three kinds of replica signals generated from a replica word and bit scheme. The bubble shift operation is achieved with a bit swap cell which swaps its own value with neighboring cells asynchronously and in parallel. This concentration of asynchronous techniques used in the memory allows for a 35-ns search-time for a 64 word × 128 bit macro with 0.13-μm 7-layer CMOS process.