快速傅里叶变换与线性调频Z变换联合算法在光纤法布里-珀罗传感器解调中的应用

将快速傅里叶变换(FFT)与线性调频Z变换(CZT)联合变换的方法应用到法布里-珀罗(F-P)腔传感器的解调中,从理论上分析了该方法的解调原理及误差.模拟计算得出,该联合算法解调出的腔长的相对误差达到0.01%,腔长的最大绝对误差小于0.05 μm.在对测量范围为O～3 MPa的F-P腔微机电系统(MEMS)压力传感器进行的解调试验中,该算法可以辨别0.01 MPa的压力,腔长与压力数据的拟合度为0.99316,测量压力与实际压力的标准偏差小于0.005 MPa.实验结果表明,FFT与CZT联合解调的方法可以在较少计算量的基础上达到较高的精度,满足实际需求.

Application of FFT Algorithm Associated with CZT in Demodulation of Fabry-Pérot Pressure Sensors

The fast Fourier transform (FFT) demodulation method conbined with chirp Z-translation (CZT) is adopted for Fabry-Pérot pressure sensors and its principle and error are analyzed theoretically. In the simulation, cavity lengths from 397 to 403 μm with the space of 0.5 μm are simulated. The result shows that the relative error by this new method is less than 0.01% and the maximum absolute error is less than 0.05 μm. In the experiment of the demodulation of the MEMS Fabry-Pérot pressure sensor, whose metrical range is from 0 to 3 MPa, its resolution reaches 0.01 MPa, its linearity between the length of the cavity and pressure achieves 0.99316 and the standard deviation between measured pressures and real pressures is less than 0.005 MPa. Experiments show that this new method adapts to the practical demand with higher resolution and less calculation consumption.