电定标热释电辐射计系统的数字相位计  

A digital phasemeter on ECPR system

作　　者：张祥安[1] 高鹏飞[1] 

机构地区：[1]上海理工大学光电信息与计算机工程学院,上海200093

出　　处：《光学仪器》2013年第5期15-19,共5页Optical Instruments

摘　　要：基于Altera公司cycloneIII系列EP3C5芯片,提出了一种基于电定标热释电辐射计(ECPR)系统中一种数字相位计的实现方法。该相位计的作用是调整系统中被测信号和参考信号之间的相位差,使得相敏检波的幅度达到最大,从而提高光功率的检测精度。将被测信号A/D转换成数字信号送到FPGA芯片中,与查找表中的参考信号做I-Q正交解调算法,得到一组I-Q值利用CORDIC算法计算arctan函数获取相位差,最后做出相应的信号同步调整。实验结果表明,该相位计使辐射计系统的测量光功率值的精度得到了改善和提高,系统运行更加稳定,当测量精度为1mW,其不确定度为1%。Based on the Altera EP3C5 FPGA chip, a digital phasemeter on electrically calibrated pyroelectric radiation （ECPR） system is introduced. The function of the phasemeter is to adjust the measured signal and reference signal in order to get the maximum amplitude in phase sensitive detector module, thus improve the optical power detecting accuracy. The method is to use A/D convert to get digital signal from the analog measured signal, and thus let the output do the multiply with look-up table in FPGA ROM based on the I-Q orthogonal algorithm, then use CORDIC to get phase difference value, finally do the adjustment. The experiment shows that the digital phasemeter improves the ECPR detecting precision, and makes the whole system more stable and reliable, and the uncertainty is under 1~ when the precision is lmW.

关 键 词：数字相位计 FPGA I-Q正交算法 ECPR 

分 类 号：TM932[电气工程—电力电子与电力传动]