Duan Fajie, Huang Tingting, Jiang Jiajia, Fu Xiao, Ma Ling
Appl Opt. 2017 Jun 1;56(16):4807-4813. doi: 10.1364/AO.56.004807.
A simple lock-in detection technique especially suited for digital phase-generated carrier (PGC) demodulators is proposed in this paper. It mixes the interference signal with rectangular waves whose Fourier expansions contain multiple odd or multiple even harmonics of the carrier to recover the quadrature components needed for interference phase demodulation. In this way, the use of a multiplier is avoided and the efficiency of the algorithm is improved. Noise performance with regard to light intensity variation and circuit noise is analyzed theoretically for both the proposed technique and the traditional lock-in technique, and results show that the former provides a better signal-to-noise ratio than the latter with proper modulation depth and average interference phase. Detailed simulations were conducted and the theoretical analysis was verified. A fiber-optic Michelson interferometer was constructed and the feasibility of the proposed technique is demonstrated.
本文提出了一种特别适用于数字相位生成载波（PGC）解调器的简单锁相检测技术。它将干扰信号与矩形波混合，这些矩形波的傅里叶展开包含载波的多个奇次谐波或多个偶次谐波，以恢复干扰相位解调所需的正交分量。通过这种方式，避免了乘法器的使用，提高了算法效率。从理论上分析了所提技术和传统锁相技术在光强变化和电路噪声方面的噪声性能，结果表明，在适当的调制深度和平均干扰相位下，前者比后者具有更好的信噪比。进行了详细的仿真并验证了理论分析。构建了一个光纤迈克尔逊干涉仪，证明了所提技术的可行性。
