MultiFunction Threshold Gates

Threshold logic gates, up to now, generally have been presumed to provide a single function of the input variables. The threshold gates that have been integrated [I1]-4] were naturally double-sided and provided complementary outputs or, more specifically, complemented dual outputs. This paper shows that the inphase and out-of-phase outputs can, in fact, be designed to provide grossly different functions of the input variables. Two examples of this technique have already been shown [5] and one of these, the full adder, has been demonstrated in a multiplier [6]. Now this technique is generalized, and furthermore, it is shown how each side can be subdivided to provide a number of functions simultaneously. Finally, virtual oRing of specific output points from each side will result in still more functions. The sum-resistor specification for any order function on either side is given. Practical application of these techniques are discussed, including those basic ones that have already been disclosed. Conventional threshold logic has already been shown to provide improvements compared to NAND or OR/NOR gates in such factors Manuscript received January 24, 1972; revised May 22, 1972, and August 18, 1972. The author is with the Advanced Communications Laboratory, RCA Corporation, Somerville, N. J. 08876. as versatility, interconnection complexity, component count, power, and speed. The multifunction threshold-gate approach will further improve these factors for many applications.