三值光学处理器的MSD数据正/负值判断器设计与实现

Design and Implementation of Positive and Negative Discriminator of MSD Data for Ternary Optical Processor

数值正/负或零判断器是计算机比较数据大小的必备器件,随着三值光学处理器中采用三态光信号表示信息的MSD(modified signed-digit)数并行加法器的出现,研究三态光信号所表达数值的正/负或零值判断器成为完善三值光学处理器的重要一环.根据MSD数的特点,通过对三态光信号的变化规律与MSD数据的对应关系的研究,提出了从一组三态光信号来判断其表达的多位MSD数据正/负特性或零值的方法.将这一方法用于2个不定长MSD数据的差运算结果,实现了判别2个MSD数据的大小或相等.依据上述理论,建立了以偏振片、液晶和半反半透镜为主要器件构造的MSD数据判断器结构,加以FPGA作为控制电路,实现了光电混合模式的3位MSD数据判断器.通过实验证明了该判断器的有效性,进而证明了其基本理论的正确性和结构设计的可行性.

The numerical positive/negative or zero value discriminator is a key component to comparethe data size in computer.With the advent of the MSD(modified signed-digit)parallel adder which using three state optical signal to express number in the ternary optical processor,the research ofpositive/negative or zero value discriminator of MSD digit is becoming an important test to perfectternary optical processor.Based o n the characteristics of MSD data and the correspondence of theoptical signal and the M S D digit,this paper proposes a method to ascertain the positive/negative orzero value of the multi-bit MSD data via direct analysis of agroup of tree state optical signals whichexpressing the MSD data.B y applying this method to the subtraction result of MSD data,it is realizedto discriminate the size of two MSD data.According to the ab ove theory,in this paper a structure ofMSD data discriminator is established,which is made of polarizer,liquid crystal and half-mirror.Inaddition to F PGA as the control circuit,a3-bit M S D data discriminator is realized.The validity of thediscriminator is proved by some experiment,and the correctness of the basic theory and the feasibilityof the structural design are proved too.