Analysis of radix searching of exponential bidirectional associative memory

The exponential bidirectional associative memory (eBAM) is a high-capacity associative memory. However, in the hardware realisation of eBAM, increasing efforts have been made to obtain an optimally small radix of exponential circuit for the fixed dynamic range of the VLSI circuit transistor, thereby allowing the dimension of the stored patterns to reach maximum. In this paper, the authors prove the stability of eBAM. The absolute lower bound of the radix of the eBAM is also obtained. In addition, an algorithm is presented to compute the optimal radix of an exponential circuit. To preserve the optimality of the radix, an algorithm capable of updating the radix when new pattern pairs are to be installed is proposed. Moreover, a deterministic method is presented to train and install pattern pairs with a predetermined fault tolerance ability