基于FPGA脉冲幅度分析器的数字化基线估计方法

Baseline estimation method of digital multi-channel pulse height analyzer based on FPGA

从对数字化波形基线求取的准确性、实时性、灵敏度以及算法对硬件资源占有量等方面出发,分析直方图统计法和平均值法的优劣,提出了一种动态实时提取随机信号数字化波形基线的方法,并利用基于现场可编程门阵列(Field-Programmable Gate Array,FPGA)的数字多道脉冲幅度分析器对几种方法进行了测试。直方图统计法具有较高的准确性,将其结果与动态实时提取随机信号数字化波形基线方法的实验结果进行比较,验证了该方法在占有较少硬件资源和计数率较高的条件下,同样具有较高的准确性、实时性和灵敏度,并且对能谱分辨率有所改善。

Background： Histogram statistics method and average value method are widely used to obtain the baseline of nuclear signal processing. However, there still exist several shortcomings, such as low accuracy, weak real-time character and high hardware resource occupancy. Purpose： This study aims to improve the accuracy and the real-time performance of the baseline extraction for the digital nuclear instruments. Methods： A novel method of obtaining baseline is proposed, it is a real-time dynamic average method that can be easily implemented on a Field-Programmable Gate Array （FPGA） based multi-charmel pulse height analyzer. By setting appropiate parameters, the accuracy and real-time character could be obviously improved. Results： This novel method not only occupies less hardware resource, but also achieves higher accuracy. The energy resolution of 137Cs spectrum is got improved to 7.44%. Conclusion： This method can be applied to extract baseline of digital multi-channel pulse height analyzer with high accuracy and real-time response.