A self-timed redundant-binary number to binary number converter for digital arithmetic processors

Abstract

This paper presents a self-timed converter circuit which converts an n-digit redundant binary number to an (n+1)-bit binary number. Self-timed refers to the fact that the conversion is problem-dependent and requires variable conversion time to complete the operation. The propagation delay of the proposed converter circuit does not increase with the number of digits to be converted, but it is determined by the maximum number of consecutive 0's in that number. This study shows that the statistical upper bound of the average maximum number of consecutive 0's is log/sub 3/n, or 3.78 for 64-digits. This implies that the proposed self-time circuit can be approximately 17 times faster than the ripple-type converter. Thus the proposed converter is well-suited to high-speed, long-word digital arithmetic processors.