An optical implementation method for symmetric MSD number

Symmetric modified signed-digit (MSD) number is much advantageous over other numbers. It can implement optical addition operation in one step without carry delay which will much affect the efficiency of numerical operation in computer system. However, study on how to obtain symmetric MSD (SMSD) number has been little concerned. Based on the mapping relations between common MSD number and SMSD number, conversion rules are presented. Following the rules, the optical paths of the converters to implement the conversion are designed. Combining the converters, the optical path of the general converter that can be used to implement the conversion from common MSD number to SMSD number is presented. Simulation results show that the method and the optical path of the converter are correct. They can be used to effectively convert MSD number into the corresponding SMSD number.