基于线性插值的相位生成载波算法动态范围上限提高

Improvement of Dynamic Range Upper Limit for Phase Generated Carrier Algorithm Based on Linear Interpolation

在干涉型光纤传感器相位解调中,为了提高相位生成载波(PGC)算法的动态范围上限,提出基于采样数据点线性插值的PGC改进算法。在特定载波调制深度和初始相位条件下,以6倍载波频率进行数据采集,通过对单个载波周期内的6个采样点进行线性插值,得到6组关于待测信号的正交项,通过微分交叉相乘(DCM)或反正切(ATAN)完成相位解调。所提算法无需载波混频和低通滤波,降低了算法的复杂度。理论分析表明,改进PGC算法的动态范围上限可提高1.58 dB。实验结果表明,采样频率为500 kHz,信号频率为2 kHz时,解调算法输出峰值达到27.32 rad,动态范围上限提高至14.36 dB,解调相关性高达99.98%。

For the phase demodulation of interferometric fiber optic sensors,an improved phase generated carrier(PGC)algorithm based on the linear interpolation of sampled data points was proposed to improve the dynamic range upper limit of PGC algorithms.Under a specific carrier modulation depth and initial phase conditions,data collection was performed at a frequency that was six times the carrier frequency.Through the linear interpolation of six sampling points within a single carrier cycle,six sets of orthogonal terms regarding the test signal were obtained.Phase demodulation was completed through differential cross multiplication or arctangent.Furthermore,the proposed algorithm does not require carrier mixing and low-pass filtering,thereby reducing the complexity of the algorithm.Theoretical calculation suggests that the dynamic range upper limit of the PGC algorithm can be increased by 1.58 dB.Experiment shows that when the sampling and signal frequencies are 500 kHz and 2 kHz,respectively,the peak output of the demodulation algorithm reaches 27.32 rad,upper limit of the dynamic range increases to 14.36 dB,and demodulation correlation becomes as high as 99.98%.