Quantization error analysis of the radix-4 signed-digit arithmetic

The quantization error characteristics of the signed-digit arithmetic are studied for the application to the MSD (Most Significant Digit) first digit serial computation, where only truncation is allowed for the word-length reduction of the multiplied results. This study shows that truncated results in the signed-digit arithmetic contain very little DC error when a symmetric remainder reduction scheme is employed. The error characteristics are similar to those of the rounding scheme in the two´s complement number system. However, the symmetric remainder reduction scheme demands more hardware and delay than the asymmetric reduction scheme.