基于正交信号融合计算的相位解调算法  

Phase Demodulation Algorithm Based on Quadrature Signal Synthesis Calculation

作　　者：宋宪晨 唐东林[1] 丁超 Song Xianchen;Tang Donglin;Ding chao(MOE Key Laboratory of Petroleum and Natural Gas Equipment,School of Mechanical Engineering,Southwest Petroleum University,Chengdu 610500,Sichuan,China;School of Intelligent Manufacturing,Chengdu Technological University,Chengdu 611730,Sichuan,China)

机构地区：[1]西南石油大学机电工程学院石油天然气装备教育部重点实验室,四川成都610500 [2]成都工业学院智能制造学院,四川成都611730

出　　处：《光学学报》2023年第22期125-135,共11页Acta Optica Sinica

基　　金：四川省科技支撑计划(2021YFSY0024)。

摘　　要：针对载波外调制过程中引入的调制深度偏移以及载波相位延迟等因素对光纤地震计解调结果的影响,提出一种多级正交信号融合计算方法,综合考虑三级倍频载波以及三级贝塞尔函数对解调效果的影响,并在此基础上计算载波相位延迟θ和相位调制深度C,实现对解调结果的误差补偿。实验结果表明:多级正交信号融合计算方法改善了表征解调结果非线性失真程度的总谐波失真,解调结果改善后总谐波失真达到-90 dB,同时解调结果信纳比达到84 dB,综合二者可看出所提算法对相位延迟θ和调制深度C具有强鲁棒性;所提算法解调结果可达到√Hz的本底噪声水平;所提算法解调结果相位延迟稳定在0°左右,与其他算法的结果相比,所提多级正交信号融合计算方法对于信号解调具有更好的实时性。Objective Conventional phase generation carrier(PGC)demodulation methods include two main approaches of differential and cross multiplying PGC(PGC-DCM)and arctangent PGC(PGC-ARCTAN).Their correct demodulation requires the carrier phase delay and modulation depth to be maintained at specific values.However,in practice,propagation delays in the optical path,analog-to-digital conversion in the signal acquisition system,and interference caused by the PIN photodetector can introduce phase delays between the carrier signal and the modulated carrier signal.Additionally,the modulation depth C is related to the amplitude of the carrier signal and the parameters of the phase modulator,and it changes with the optical wavelength,temperature,and humidity in the actual operating environment,resulting in random drift and fluctuation of C value.These unstable factors directly affect the operation of the entire demodulation system,causing harmonic distortion of the demodulated signal and even demodulation failure.Therefore,solving the instability problems of C value and phase delay is an important task to improve the stability and accuracy of the demodulation system.Nowadays,many scholars have calculated the modulation depth and phase delay by employing different octave carriers compensation to solve this problem and yielded some results.However,the high-order Bessel function and high octave carriers are prone to introduce high-frequency harmonics in the demodulation results,which causes certain nonlinear distortion.Meanwhile,as different multicarriers and different orders of Bessel functions also affect the demodulation results,it is very important to determine the appropriate carrier multiplicity and Bessel order for accurate demodulation.Methods Considering the influence of different octave carriers and different orders of Bessel functions on the demodulation results,we propose a multistage orthogonal signal fusion(MOSF)computation method that synthesizes the triple-octave carriers and the third-order Bessel functions.Firstly,

关 键 词：光纤光学 光纤振动传感 相位生成载波 相位解调 相位延迟 调制深度 

分 类 号：TN29[电子电信—物理电子学]