光纤声传感反正切解调的采样率与信号幅度关系

针对光纤光栅声传感系统反正切解调算法中采样率与声场幅度相关这一现象,本文计算分析了正弦声信号、高斯脉冲声信号在三种不同反正切算法下幅度与采样率的关系,用脉冲声信号进行了实验验证,并从相位展开方式的判据出发予以机理解释,以期望在应用前可根据声场、传感器灵敏度等选择恰当的采样率。数值计算和实验结果表明,这三种方式需要的采样率均与信号幅度呈线性关系,分别需要一个声周期内采样点数为信号幅度的8倍、4倍和2倍。此外,本文还将三种方式与DCM算法在软件计算时的实时性和计算精度进行了比较,在满足采样率要求时三者均较DCM算法的表现更佳。

Relationship between sampling rate and signal amplitude of arctangent demodulation algorithm in optical fiber acoustic sensing system

Aiming at the phenomenon that the sampling rate is related to the amplitude of sound field when using an arctangent algorithm, the quantitative relationship between the sampling rate and the signal amplitude is studied by calculating and analyzing situations of sinusoidal signal and Gaussian pulse signal under three different algorithms, which helps select an appropriate sampling rate according to sound field and sensor sensitivity before application. Simulation and experimental results indicate that there exist linear relationships between sampling rates and signal amplitude under three algorithms, that sampling points per wavelength need to be 8, 4 and 2 times of signal amplitude, respectively. In addition, compared with DCM algorithm, arctangent algorithms all perform better on real time and accuracy when satisfying sampling rate requirements.