Abstract: Several kernel CMOS circuits for radial basis function (RBF) networks are proposed, including current type absolute circuit, mean square root circuit, and an adjustable Gaussian circuit.A two-input/one-output RBF network with two hidden nodes composed of these circuits is implemented and verified for the XOR problem.All the circuits were fabricated in HJTC 0.18μm CMOS technology.The chip area is 200μm×150μm and the power consumption is about 100μW.Experimental results show that all the proposed circuits provide simple structures, low power consumption, and high operation capacity.This demonstrates the possibility of a hardware implementation for on-chip learning in an RBF network.

Key words: RBF network, hardware implementation, CMOS analog circuits, Gaussian circuit