A Truth Table Method for the Synthesis of Combinational Logic

This paper describes a method for synthesizing a switching function directly from its: ruth table. A switching function is defined as any mapping of a set of binary input combinations onto 0 and 1. Hence, the procedures apply equally well to the don't care cases. The method rests on the concept alogically passive function (LPF). Roughly speaking, an LPF is a truth table which can be realized with only AND and OR gates-no inverters. Techniques are described for 1) making a function logically passive, 2) eliminating rows and columns from the truth table of an LPF, 3) synthesizing an LPF in a two-level irredundant form, 4) expanding LPF's and 5) synthesizing LPF's with 3-input majority gates. The underlying methods are quite straightforward and appear to be particularly well suited for mechanization on a digital computer.