INFORMATION CAPACITY OF ITERATIVE LOGIC CIRCUITS,

The capacities of various iterative-circuit logic structures required to realize logic and computing functions are compared. A circuit tunable by external 0--1 signals at whose output any Boolean function of n variables can be realized is called a universal logic element ULE. Such an element may have one or more independent outputs, each yielding any of 2 to the power2 to the power n Boolean functions of n variables. Two versions of ULE, with one and two outputs, are described. A 3-tier iterative-circuit structure built from ULEs yields all possible 256 Boolean functions of three input variables this structure has 3 inputs, 3 outputs, and 9 ULEs. A 5-tier iterative-circuit structure and the above 3-tier structure made up of 2-input ULEs require for their tuning information capacity and redundancy almost equal to those of a 2-dimensional lattice structure consisting of outpoint elements the required capacity and redundance are 124 to 127 of those needed for a computing medium simple-recurrent-circuit structure or a simple lattice structure. Hence, a more complex ULE is preferable for building up intricate combination schemes, etc.