Opto-electronic emulation of a programmable digital circuit

Abstract

A programmable digital circuit typically consists of a microprocessor, a memory device, an input data device and an output data device, with its corresponding communication busses. These devices work following a program which is stored in the memory device, as codified instructions. An opto-electronic system that emulates a programmable digital circuit is proposed and described in this work. This circuit is commanded by a sequential program stored as a spatial distribution of Fourier Holograms into a photorefractive crystal. The sequential program is conformed by instructions, which have been codified as binary pixels maps. To read and decode each instruction, the spatial position of the photorefractive crystal must change; and then a CCD camera captures the output image of the Fourier Hologram. Our LabVIEW software decodes the instruction from the captured output image and it commands the circuit to realize the decoded instruction. This software controls the CCD camera and an electromechanical system which moves the spatial position of the photorefractive crystal. The electromechanical system is continuously in communication with a PC through our software. This is because the electronic circuit of the electromechanical system, moves three stepper motors; depending on the position in which the crystal needs to be to read the next instruction. The experimental results and the complete description of the practical advantages and disadvantages of the complete engineering system and the emulation of the opto-electronic programmable digital circuit will be described in this work.