Dynamic Spectrum Data Acquisition System Based On FPGA

Near-Infrared spectroscopy receives global attention as a principal non-invasive diagnostic means.However, individual differences and measuring conditions are more prominent problem that affect non-invasive detection of blood components when using Near Infrared spectrum. Therefore, PhD Li put forward the conception of Dynamic Spectrum method, with which we can remove the effect of the individual differences and measuring conditions.In this paper, based on the Dynamic Spectrum method we designed a dynamic spectrum data acquisition system based on FPGA.According to performance requirements of the dynamic spectrum data acquisition system, high-performance linear CCD IL-C6-2048C was selected as photoelectric converter; High-speed, high-precision, and with CDS ADC AD9826 was selected to acquire CCD's high speed and weak signal; FPGA and NIOS II microprocessor were the core controller and data were displayed with LabVIEW.In FPGA, CCD and the AD9826 control timing was designed by Verilog HDL languages; Ping-pong operating units were made up of Pair of dual-Port RAM, which avoided using NIOS II processor directly read data through the frequent interruption. NIOS II processor system embedded in the FPGA and managed the entire system. It used interrupted way to read the data in the cache unit, after natural logarithm transform the results were transmited to the computer. The data catch reading unit and natural logarithm transform unit were added to NIOS II system as User-defined logic, and could be used directly while programming. NIOS II system transmited data to LabVIEW through the serial port, and LabVIEW displayed the data.At last, the capability of the system is analyzed. The experimental results provide verification of its good sampling and displaying ability.