高速度高精度光纤布拉格光栅解调的寻峰算法研究

Research on peak-detection algorithm for high-speed and high-precision FBG demodulation

为实现高速度、高精度的光纤光栅传感解调,提出了一种基于状态机的自适应半峰检测寻峰算法。算法通过对FBG反射波形的实时跟踪确定波形数据,通过对波形数据的统计分析得到寻峰阈值,通过校验与补偿精确得到峰值位置。实验测试表明,对于2kHz的解调速度,解调分辨率达到1pm,静态噪声在±2pm以内,长时间测试的稳定性误差在2pm以内,系统动态范围在0～-30db,光功率衰减导致的稳定性误差在4pm以内。这表明,本算法从速度、精度、抗干扰性、稳定性等方面都能够满足高速解调的需要。

To satisfy the requirements of high-speed and high-precision demodulation applications, an adaptive semi-peak-seek algorithm based on state machine is proposed. The proposed algorithm determines the waveform data by real-time tracking of the FBG reflection waveform. Through statistical analysis of the waveform data, a peak-seek threshold can be achieved, and then the precise position of the peak can be obtained by means of calibration and compensation. From the experimental results, the demodulation distinguishability can reach 1 pm while the demodulation speed is 2 kHz,at the same time the static noise is less than ± 2 pm. The stability error of less than 2 pm is concluded in a long term test. As the system dynamic range is from 0 to --30 dB, the measurement error within the dynamic range is limited to 4 pm. Thus, the requirements of high-speed demodulation, such as speed, precision, stability and anti-interference properties, can be achieved by this algorithm.