DESIGN AND EVALUATION OF A 4-VALUED UNIVERSAL-LITERAL CAM FOR CELLULAR LOGIC IMAGE-PROCESSING

This paper presents a 4-valued content-addressable memory (CAM) for fu lly parallel template-matching operations in real-time cellular logic image processing with fixed templates. A universal literal is essentia l to perform a multiple-valued template-matching operation. It is deco mposed of a pair of a threshold operation in a CAM cell and a logic-va lue conversion shared by CAM cells in the same column of a CAM cellula r array, which makes a CAM cell function simple. Since a thresh old op eration together with a 4-valued storage element can be designed by us ing a single floating-gate MOS transistor, a high density ii-valued un iversal-literal CAM with a single-transistor cell can be implemented b y using a multi-layer interconnection technology. It is demonstrated t hat the performance of the proposed CAM is much superior to that of co nventional CAMs un der the same function.