Threshold logic implementation of a modular computer system design
J. H. Beinart, D. Hampel, K. J. Prost · NASA Technical Reports Server (NASA) · 1970
AbstroctSeveral portions of logic of the NASA Modular Computer, t o be b u i l t with LSI, were designed w i t h threshold logic.Some of the designs were compared w i t h TTL NAND gate implementations.The logic designs for each function were characterized by t o t a l component count, connections, speed and power.The threshold logic circuits used arrays of current switching modules t o r e a l i z e such functions as parity, parallel shift and r o t a t e logic, decoding, registers and counters.The designs were based on a family of integrated threshold gates developed in 1968-1969 and which were shown t o be amenable t o LSI.New circuit techniques are shown t o simplify logic where, t r a d i t i o n a l l y , pure threshold logic has not shown advantage.Depending on the number of components used f o r a TTL NAND gate, i n an array, the component savings provided by threshold logic ranged from s l i g h t l y l e s s t h a n 2 t o 1 t o over 3 t o 1 .Gate interconnection complexit, was shown t o be reduced by 5 t o 1 i n the p a r i t y c i r c u i t t o 1.5 t o 1 f o r a switch.Logic function delays were generally decreased by almost 3 t o 1 with the threshold logic while the power dissipation to achieve this was CV.