Low power circuit design has been one of the major growing concerns in integrated circuit technology. Reversible circuit (RC) design is a promising future domain in computing which provides the benefit of less computational power. With the increase in the number of gates and input variables, the circuits become complex and the need for fault testing becomes crucial in ensuring high reliability of their operation. Various fault detection methods based on exhaustive test vector search approaches have been proposed in the literature. With increase in circuit complexity, a faster test generation method for providing optimal coverage becomes desirable. In this paper, a genetic algorithm-based heuristic test set generation method for fault detection in RCs is proposed which avoids the need for an exhaustive search. Two approaches, one involving random search and the other, involving directed search have been proposed and validated on benchmark circuits considering missing-gate fault (complete and partial), bridging fault and stuck-at fault with optimum coverage and reduced computational efforts.

Arithmetic operations in digital signal processing applications suffer from problems including propagation delay and circuit complexity. QSD number representation allows a method of fast addition/subtraction because the carry propagation chains are eliminated and hence it reduces the propagation time in comparison with common radix 2 system. Here we propose an arithmetic unit based on QSD number system based on quaternary system. The proposed design is developed using VHDL and implemented on FPGA device and results are compared with conventional arithmetic unit. The implementation of quaternary addition and multiplication results in a fix delay independent of the number of digits. Operations on a large number of digits such as 64, 128, or more, can be implemented with constant delay and less complexity.