"Bump" Circuits for Computing Similarity and Dissimilarity of Analog Voltages

Tliis paper describes two siiiall analog circuits that compute generalized measures of tlie siiiiilarity of two voltage inputs. The siiiiilarity outputs from tlie circuits, given as currents, bccome large wheii tlie input voltages are close to each other. One of tlie circuits, tlie bump circuit, coiiiputcs oiily this siiiiilarity output. The other circuit, tlie bump-anti-bum,p circuit, coiiiputes tlie similarity output as well as a dissimilarity measure; each of its dissimilarity outputs becomes large only when tlie corresponding input is sufficiently larger than the other input. The dissimilarity outputs caii be suiiiiiied together or left separate; when left separate, they r(~semble generalized rectifier outputs. Test results are presented that illustrate these transfer characteristics.