B.S.T.J. Brief: A Josephson parallel multiplier

This report describes the operation of an 8-x 12-bit parallel multiplier which employs Josephson tunnel junctions (Fig. 1).1∗ The device contains 548 junctions used in two-junction “Jaws”-type logic elements.2 Ninety-six of these logic elements function as AND gates to form the partial products. Their outputs are fed into a Wallace-tree3 arrangement of 89 full adders, each having one Jaws for the CARRY computation and one for the SUM. The thirteen most significant bits of the product are returned to the outputs.