Logical Design of Quaternary Signed Digit Conversion Circuit and its Effectuation using Operational Amplifier

In binary number system carry is a major problem in arithmetical operation. We have to suffer O(n) carry propagation delay in n-bit binary operation. To overcome this problem signed digit is required for carry free arithmetical operation. Further, literature reviews suggest that multi-valued logic (MVL) would be a better choice to address the problem of developing faster chips for performing faster computational operation. Quaternary Signed Digit (QSD) have a major contribution in higher radix (=4) carry free arithmetical operation. For digital implementation, the signed digit quaternary numbers are represented using 3-bit 2's compliment notation. In this paper, a simple and new technique of binary (2's compliment) to QSD conversion is proposed and described. Well-known operational amplifier (OPAMP) based digital to analog converter circuit is also given to verify the above technique.