An adaptive neural processing node

The design and test results for two analog adaptive VLSI processing chips are described. These chips use pulse coded signals for communication between processing nodes and analog weights for information storage. The weight modification rule, implemented on chip, uses concepts developed by E. Oja (1982) and later extended by T. Leen et al. (1989) and T. Sanger (1989). Experimental results demonstrate that the network produces linearly separable outputs that correspond to dominant features of the inputs. Such representations allow for efficient additional neural processing. Part of the adaptation rule also includes a small number of fixed inputs and a variable lateral inhibition mechanism. Experimental results from the first chip show the operation of function blocks that make a single processing node. These function blocks include forward transfer function, weight modification, and inhibition. Experimental results from the second chip show the ability of an array of processing elements to extract important features from the input data