Design of image sampling system used in SEM

A new image sampling system with FPGA is designed to improve the data sampling part of the old model SEM (scanning electron microscope). The design performs the logical control of the system by using FPGA. It used ADS1606 of TI Corp. as the analog-digital converter chip. The instrument amplifier, driving circuit and reference sources circuit are suitably designed according to the imaging signal. The control process of FPGA and some program edited with Verilog HDL are presented. Also, some considerations of the circuit designing is emphasized.