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理论分析了光纤光栅法布里-珀罗(F-P)传感器频分复用技术的原理,并给出了信号处理对腔长选取的要求。数值模拟结果表明,不同腔长的传感器具有不同的谐振条纹频率,为保证频域中的信号不发生重叠,要求不同光纤光栅法布里-珀罗传感器间的腔长之差必须大于光纤光栅的长度。进一步的实验及模拟分析结果发现,温度等待测量的变化仅仅使光纤光栅法布里-珀罗传感器的反射光谱整体平移,相应的频域信号只产生相移而形状不发生变化,因而不能采用普通光纤法布里-珀罗(FFP)传感器的腔长傅里叶变换解调法解调频分复用光纤光栅法布里-珀罗传感器的信号。根据这一特点,提出了利用自相关分析实现频分复用传感器系统信号解调的方案。
The principle of FBG Fabry-Perot (F-P) sensor frequency-division multiplexing is theoretically analyzed, and the requirements of signal processing for cavity length selection are given. The numerical simulation results show that the sensors with different cavity lengths have different resonant frequency. To ensure that the signals in the frequency domain do not overlap, the difference between cavity lengths of different FBG Fabry-Perot sensors must be greater than that of FBG length. The results of further experiments and simulations show that the temperature wavering measurement only shifts the reflection spectrum of the fiber grating Fabry-Perot sensor as a whole, and the corresponding frequency-domain signals only produce phase shift and the shape does not change, Fiber-optic Fabry-Perot (FFP) cavity length Fourier Transform Demodulation demodulates FDM FBG Fabry-Perot sensors. According to this feature, a scheme of signal demodulation in frequency-division multiplexing sensor system is proposed using autocorrelation analysis.