Patent ID: 7113416

Claim:
An associative memory apparatus for searching reference data REF most similar to search data SW which is input with the same unit structure, from among W×R (W and R are arbitrary natural numbers) of reference data REF which are registered in advance in a memory region and which are respectively made to be units in k-bit (k>1) units, on the basis of an index of a Manhattan distance, the apparatus comprising: a distance calculating circuit which is formed at the memory region, and which calculates an absolute value of difference |SW-REF| in parallel with the W×R of reference data REF with respect to the search data SW, and outputs a degree D of a inconsistency between both data of the calculated results as a “Manhattan distance”; and a searching circuit which searches reference data in which the calculated result of the Manhattan distance is made to be a minimum distance, wherein the distance calculating circuit comprises W columns×R rows of unit storage circuits to store the reference data in units, W columns×R rows of unit comparison circuits which calculate a Manhattan distance between the reference data and the search data for each unit, and R rows of word weight comparison circuits which generate an electric current signal or a voltage signal corresponding to a Manhattan distance calculated at the W columns of unit comparison circuits for each row, and the unit comparison circuit compares magnitudes of the reference data REF and the search data SW, and when the compared result thereof is SW>REF, (SW+(˜REF))+1 (˜denotes inversion (a complement of 1): hereinafter referred to as it) is calculated, and when the compared result thereof is SW≦REF, ˜(SW+(˜REF)) is calculated.