摘要
为了解决相位生成载波解调方案应用于激光测振技术时,系统中存在的非线性失真问题,提出一种改进相位生成载波解调算法。该算法采用低频、大幅值的相位调制和迭代重加权椭圆特殊拟合对两路含有非线性误差的正交信号进行校正以抑制非线性失真。其中,低频相位调制由三角波信号驱动压电换能器生成,确保小信号情况下椭圆拟合结果的准确性。迭代重加权椭圆特殊拟合可以减小离群数据的影响并避免拟合结果退化为双曲线,具有精度高、鲁棒性好和计算效率高的优点。实验结果表明改进相位生成载波解调算法可以有效抑制激光测振实验系统的非线性失真,在不同相位调制深度(0.8~3.4 rad)下解调信号的信纳比和总谐波失真稳定,对应的标准差分别为0.55 dB和0.03%。系统的响应线性度优于99.99%,动态范围可达103.9 dB@500 Hz,总谐波失真为1%且工作频宽为20~8000 Hz。与传统相位生成载波解调方案相比,该算法不仅显著抑制了非线性失真,还克服了椭圆拟合算法在小信号下无法工作的缺点。
Phase Generated Carrier(PGC)demodulation algorithm has been widely used in laser coherent vibration measurement and gained widespread interest due to its high accuracy,large dynamic range,good linearity,and low hardware overhead.However,the PGC demodulation technology is always accompanied by nonlinear distortions induced by phase modulation depth deviation,light intensity disturbance,carrier phase delay,etc.Therefore,an improved PGC demodulation algorithm is urgently required,which can effectively suppress the nonlinear distortions.In this study,we propose an improved PGC demodulation algorithm based on low frequency modulation and iteratively reweighted ellipse specific fitting,which suppresses the nonlinear distortions in the laser vibration measurement.The ellipse specific fitting is realized by introducing a 6×6 ellipse constraint matrix in the direct least square fitting of ellipse,which avoids getting a hyperbola solution,consequently.The iteratively reweighted ellipse specific fitting uses iteratively reweighted optimization technology to improve the precision of the ellipse specific fitting and reduce the weight of the outlier data,it has the advantages of ellipse-specificity,high robustness and high precison.In the imrpoved demodulation algorithm,the iteratively reweighted ellipse specific fitting is used to correct the original quadrature signals into a pair of perfect quadrature signals,which eliminates the nonlinear errors.Furthermore,to overcome the drawback of the ellipse fitting algorithm that it fails to work correctly under small phase signals,a low frequency modulation with a large amplitude is added in the carrier modulation and it guarantees the ellipse fitting accuracy regarless of the desired signal amplitudes.Finally,differential cross multiplying is used to extract the desired phase shift signal from the corrected quadrature signals.The simulations of ellipse specific fiting and iteratively reweighted ellipse specific fitting are performed and the results show that the iteratively reweig
作者
蒋翌超
顾劭傑
张刚
许林广
葛强
吴许强
俞本立
JIANG Yichao;GU Shaojie;ZHANG Gang;XU Linguang;GE Qiang;WU Xuqiang;YU Benli(School of Electrical Engineering,Anhui Polytechnic University,Wuhu 241000,China;School of Mathematics Physics and Finance,Anhui Polytechnic University,Wuhu 241000,China;Information Materials and Intelligent Sensing Laboratory of Anhui Province,Anhui University,Hefei 230601,China)
出处
《光子学报》
EI
CAS
CSCD
北大核心
2024年第1期42-56,共15页
Acta Photonica Sinica
基金
安徽省高校自然科学研究项目(No.2022AH050964)
安徽工程大学引进人才科研启动基金项目(Nos.2021YQQ057,2022YQQ098)
信息材料与智能感知安徽省实验室开放课题(Nos.IMIS202104,IMIS202212)
国家自然科学基金(No.51627804)
国家级大学生创新创业训练项目(No.202210363096)。
关键词
激光测振技术
相位生成载波解调算法
低频调制
迭代重加权椭圆特殊拟合
非线性失真
Laser vibration measurement technology
Phase generated carrier demodulation algorithm
Low frequency modulation
Iteratively reweighted ellipse specific fitting
Nonlinear distortions
