基于FPGA的激光外差干涉仪反正切解调技术  

Technology of Arctangent Demodulation of Laser Heterodyne Interferometer Based on FPGA

作　　者：柯伟 冯秀娟[1] 杨平[1] 何龙标[1] 邢广振 王敏[1] KE Wei;FENG Xiu-juan;YANG Ping;HE Long-biao;XING Guang-zhen;WANG Min(National Institute of Metrology,Beijing 100029,China)

机构地区：[1]中国计量科学研究院,北京100029

出　　处：《计量学报》2022年第3期399-404,共6页Acta Metrologica Sinica

基　　金：国家重点研发计划资助(2017YFF0205004)。

摘　　要：针对高频声学应用中多普勒信号软件解调的局限,提出了一种基于FPGA的数字硬件信号解调方案。基于AD9467设计了高速ADC采集系统,以实现原始多普勒信号的奈奎斯特采样或带通采样;基于Xilinx Zynq-7000片上芯片系统设计数字信号处理系统,实现了DDS合成参考信号与多普勒信号混频、低通滤波产生I&Q基带信号对,采用CORDIC算法对I&Q基带信号对反正切解调得到待测振动位移,实现了多普勒信号的实时解调。50~500 kHz范围的数值仿真和50~300 kHz范围的初步实验结果验证了设计方案的可行性。In order to eliminate the limitations of Doppler signal software demodulation in high-frequency acoustic applications,a digital hardware signal demodulation approach based on FPGA is proposed.It contains a high-speed ADC acquisition system based on AD9467 to implement the Nyquist sampling or band-pass sampling of the original Doppler signal.The digital signal processing system based on Xilinx Zynq-7000 SoC is designed to generate the I&Q baseband signal pair,which is obtained by mixing of DDS synthesized reference signal with Doppler signal and the following low-pass filtering.The CORDIC algorithm and phase unwrapping algorithm are used to demodulate the I&Q baseband signal pair and the real-time demodulation of Doppler signals is initially realized.Numerical simulation in the frequency range from 50 kHz to 500 kHz and the preliminary experimental results in the frequency range from 50 kHz to 300 kHz demonstrate the validation of the demodulation method and system.

关 键 词：计量学 声学测量 激光外差干涉仪 反正切解调 FPGA 

分 类 号：TB95[一般工业技术—计量学]