中国激光, 2011, 38 (12): 1205001, 网络出版: 2011-11-28
用于体温心音检测的光纤布拉格光栅波长解调方法
Wavelength Demodulated Method of Fiber Bragg Grating for Human Temperature and Heart Sound Measuring
光纤光学 光纤布拉格光栅 静态波长解调 动态波长解调 光纤法布里珀罗滤波器 fiber optics fiber Bragg grating static wavelength demodulation dynamic wavelength demodulation fiber Fabry-Perot filter
摘要
提出一种用于智能服装中体温与心音同步检测的光纤布拉格光栅(FBG)波长解调方法。基于可调谐法布里珀罗(F-P)滤波器实现了分布式多光纤光栅的高精度静态波长解调和单光纤光栅的高速动态波长解调。利用梳状滤波器实现F-P控制电压与输出波长关系的实时校准,提高了静态波长解调的精度。通过在控制电压中加入扰动信号,使F-P滤波器中心波长在工作点处保持稳定,实现长时间的动态解调。实验结果表明所设计的解调系统静态波长解调精度可达±5 pm,重复性在5 pm以内。动态波长解调范围理论值为225 pm,实测可达203 pm。系统频率响应3 dB带宽设计值为1 kHz,实测值为950 Hz左右。在心音信号主要集中的20~200 Hz频段内,频率响应基本一致。
Abstract
A wavelength demodulated method of fiber Bragg grating (FBG) is proposed to measuring human temperature and heart sound, which can achieve distributed static wavelength demodulation of multi-FBGs and dynamic wavelength demodulation for single FBG. The relation between control voltage of Fabry-Perot (F-P) filter and its output wavelength is rectified by pectinate filter, so the precision of static demodulation is improved. By adding dithering signal the center wavelength of F-P filter could be remained on work point so that it could demodulate dynamic wavelength for a long time. The experiment results indicate that the precision of static wavelength demodulation is ±5 pm and the repeated error is about 5 pm. The theoretical dynamic demodulated range is 225 pm and the actual range is about 203 pm. The theory bandwidth of 3 dB of system frequency response is 1 kHz and the measured value is about 950 Hz. In the heart sound concentrated band of 20~200 Hz, frequency response are basically the same.
张诚, 苗长云, 甘晶萌, 赵军发. 用于体温心音检测的光纤布拉格光栅波长解调方法[J]. 中国激光, 2011, 38(12): 1205001. Zhang Cheng, Miao Changyun, Gan Jingmeng, Zhao Junfa. Wavelength Demodulated Method of Fiber Bragg Grating for Human Temperature and Heart Sound Measuring[J]. Chinese Journal of Lasers, 2011, 38(12): 1205001.