A universal literal circuit and its application to quaternary logic networks

A new type of universal literal circuit, in which two thresholds of the circuit are variable and controlled by external signals, is proposed herein. The circuit is designed with CMOS-FETs, and both computer simulation by FSPICE and experiments on bread-board with discrete elements confirm its correct operation. A new type of basic quaternary operator, quaternary U-gate, is also introduced. The U-gate comprises a pair of CMOS pass transistors driven by the output of the universal literal circuit. Mathematical properties of the U-gate are derived, and synthesis procedures of quaternary logic functions using U-gates are given. The quaternary U-gate and quaternary constants form a complete set of quaternary operators and its mathematical properties implicate those of CP-gates and SCP-gates.