数字多道脉冲幅度分析器中数字Dither加入方法  

Method of digital Dither adding for digital multi-channel pulse amplitude analyzer

作　　者：陈小猛[1] 张羽中[1] 艾宪芸[1] 梁卫平[1] 肖无云[1] 

机构地区：[1]防化研究院国民核生化灾害防护国家重点实验室,北京102205

出　　处：《核技术》2015年第5期45-50,共6页Nuclear Techniques

基　　金：国家科技支撑计划项目(No.2013BAK03B00)资助

摘　　要：国内对于数字多道脉冲幅度分析器(Digital multi-channel pulse amplitude analyzer,DMCA)的核心技术现已有较好掌握,但随着转换增益的提高,数字化多道如何保证非线性技术指标达到要求,仍是一项亟待解决的关键技术问题。国际上采用抖动(Dither)技术实现了数字化多道1-2位的"位增益",而国内仍未有Dither应用于DMCA相关研究的报道。本文针对数字多道脉冲幅度分析器的架构特点,提出了利用现场可编程门阵列(Field programmable gate array,FPGA)产生和去除数字Dither信号的方案,通过DMCA的基线调整电路引入Dither信号,在实验中提高了系统的微分非线性,验证了这种方法的适用性。讨论分析了Dither对于DMCA非线性的作用机理,表明这种在DMCA中加入Dither的方法对于进一步提升DMCA的精度具有重要意义。Background： The key technology of digital multi-channel pulse amplitude analyzer （DMCA） has been surmounted in China, however, with the increasing of the translation gain increases of DMCA, one of the difficulties is how to make the nonlinear performance index of the system reach the standard. Technology of Dither has been used to realize ＂Bit Gain＂ in overseas research while it is still a deficiency in DMCA study in China. Purpose： This study aims to study the application of Dither technology in DMCA and discuss relevant digital Dither technology for DMCA. Method： Based on DMCA architecture characteristics, Dither signal is produced and removed in field programmable gate array （FPGA） by linear feedback shift register （LFSR）, and is added to DMCA by the circuit of base line. Energy resolution and differential nonlinearity （DNL） of DMCA system has been measured to study the effect of Dither on DMCA. The mechanism of how the Dither affects DMCA has been analyzed. Results： Experimental tests showed that DNL of DMCA is improved by adding Dither while keep the same the energy resolution, verifying the applicability of this method. Conclusion： The technology method of digital Dither adding for DMCA is of practical significance to the further research to improve the precision of DMCA.

关 键 词：抖动技术 数字多道脉冲幅度分析器 现场可编程门阵列 线性反馈移位寄存器 微分非线性 

分 类 号：TL817[核科学技术—核技术及应用]