The Design And Implementation Of The Digital Pulse Amplitude Analyzer Based On FPGA

Methods the nuclear spectrum measurement is widely used in the fields of aerospace, resource, exploration, environmental monitoring and scientific research etc.. Multi channel pulse amplitude analyzer as a core component of the nuclear spectrum measurement system, plays an important role in the performance of the system. Along with the progress of technology, and the emergence of high performance A/D and signal processor, digital multi-channel pulse amplitude analyzer because of its energy resolution, stability and many other advantages, gradually replacing the traditional multi-channel pulse amplitude analyze,become the trend of development. Although the domestic research institutions conducted years of research on digital channel, but compared with foreign products, there is a large gap between the. Therefore, further research and design of performance of digital multi-channelpulse amplitude analyzer superiority, significance.This paper uses Actel company’s FPGA(its chip model is A3P250)(as the core unit of digital signal processing) and AD’s model for the AD9235 analog to digital converter(analog to digitalconversion module for nuclear pulse) combination, as the design of digital multi-channel pulse amplitude analyzer. All the signal processing and control functions are completed In the FPGA,including: the control of peripheral devices related to A/D sampling, the clock frequency,Gauss shape, amplitude extraction, RAM read and write, produce line, serial data transmission and 485 conversion chip control. In order to ensure the stability of long-distancedata transmission, using RS485 communication mode of transmission between theinstrument and the PC, using LTC2850 chip. The upper computer software(includingsoftware, spectrum analysis, waveform analysis software and SD software) is designed by VB 6.0 and the serial communication function is achieved through the MSComm control’s OnComm eventAfter the implementation of the hardware and software of the whole system, the selection of 137 CS, 40 K and 232 Th three kinds of radiation source, carries on the test to the threeperformance indexes of the system energy resolution, energy linearity and peak shift. The experimental data show that, the design of digital multi-channel pulse amplitude analyzerfunction, to achieve the expected goal..