Analysis of quantization effects in a digital hardware implementation of a fuzzy ART neural network algorithm

A reformulated Adaptive Resonance Theory (ART) neural network algorithm has recently been implemented in digital hardware. Naturally, the fixed point, fixed word length data format used causes some output differences with respect to floating point computer simulation. These differences are observed when using realistic input data. The effects of input quantization and the accumulation of round off errors in the arithmetic operations making up the algorithm are analyzed. Even a small quantization or round off error can trigger a change in the clustering produced. This does not mean that the clustering is not valid. Indeed, the validity of the clustering can be comparable to that obtained by floating point computer simulation, provided the word length is sufficient. This is verified on realistic input data consisting of radar pulses received from a number of emitters.