A differential phase extracting method based on self-copy-shift for distributed acoustic sensing is proposed.Heterodyne and optical hybrids are used to realize high signal-to-noise ratio in-phase and quadrature-phase(...A differential phase extracting method based on self-copy-shift for distributed acoustic sensing is proposed.Heterodyne and optical hybrids are used to realize high signal-to-noise ratio in-phase and quadrature-phase(IQ)signal measurement.The measured signals are self-copied and shifted for certain data points,and then they are digitally mixed with the original signals to construct the differential phase.The four produced signals are then combined to carry out IQ demodulation.An experiment with strain having an amplitude modulation waveform is carried out.The results showed that waveform information can be recovered well,and the signal-tonoise ratio achieves 32.8 dB.展开更多
研究了基于光纤缠绕薄壁圆筒的声增敏方法,基于3×3耦合器建立了声压灵敏度标定实验系统,实验探讨了薄壁圆筒的方向特性,实验研究了半径、壁厚尺寸参数对光纤声增敏的影响,实现的声压灵敏度达到1.338 rad/Pa(−117.47 dB re rad/μPa...研究了基于光纤缠绕薄壁圆筒的声增敏方法,基于3×3耦合器建立了声压灵敏度标定实验系统,实验探讨了薄壁圆筒的方向特性,实验研究了半径、壁厚尺寸参数对光纤声增敏的影响,实现的声压灵敏度达到1.338 rad/Pa(−117.47 dB re rad/μPa)。光纤缠绕薄壁圆筒接入所搭建的准分布式声传感系统进行实验,在20.06 km传感距离上,恢复的1 kHz正弦波形与施加波形误差不超过4.1%,比未增敏光纤环传感信噪比提高了21.03 dB,显示了薄壁圆筒声增敏的传感效果。该研究结果为高灵敏度的准分布式声传感的进一步发展提供了实验基础。展开更多
基金supported in part by the National Natural Science Foundation of China(Nos.61675152 and61735011)the National Instrumentation Program of China(No.2013YQ030915)+1 种基金the Tianjin Talent Development Special Plan for High Level Innovation and Entrepreneurship Teamthe Open Project of Key Laboratory of Opto-electronics Information Technology(No.2019KFKT007)。
文摘A differential phase extracting method based on self-copy-shift for distributed acoustic sensing is proposed.Heterodyne and optical hybrids are used to realize high signal-to-noise ratio in-phase and quadrature-phase(IQ)signal measurement.The measured signals are self-copied and shifted for certain data points,and then they are digitally mixed with the original signals to construct the differential phase.The four produced signals are then combined to carry out IQ demodulation.An experiment with strain having an amplitude modulation waveform is carried out.The results showed that waveform information can be recovered well,and the signal-tonoise ratio achieves 32.8 dB.
文摘研究了基于光纤缠绕薄壁圆筒的声增敏方法,基于3×3耦合器建立了声压灵敏度标定实验系统,实验探讨了薄壁圆筒的方向特性,实验研究了半径、壁厚尺寸参数对光纤声增敏的影响,实现的声压灵敏度达到1.338 rad/Pa(−117.47 dB re rad/μPa)。光纤缠绕薄壁圆筒接入所搭建的准分布式声传感系统进行实验,在20.06 km传感距离上,恢复的1 kHz正弦波形与施加波形误差不超过4.1%,比未增敏光纤环传感信噪比提高了21.03 dB,显示了薄壁圆筒声增敏的传感效果。该研究结果为高灵敏度的准分布式声传感的进一步发展提供了实验基础。
