光纤电流传感器微弱信号检测技术

介绍了光纤电流传感器的性能特点，详细地论述了光纤电流传感器的噪声根源及如何准确无误了检测掩理噪声中的微弱信号，着重介绍了数字多点平均技术，并给出基于数字多点平均技术的检测电路和程序流程图。     

光纤电场传感器及其信号检测系统

本文介绍一种新型的便携式光纤传感电场检测系统。从不受电磁干扰影响和安全性出发,建立在Pockels效应基础上的无源光纤电场传感器,在恶劣的电气环境下的测量、控制和防护等方面具有极大意义。最后叙述这种系统的原理、结构和性能。     

荧光微弱信号检测电路设计

荧光分析技术在现代化学分析中占有重要地位,在荧光分析仪器与传感器的研制过程中,有效提取荧光信号十分关键.在考虑检测电路内在的噪声来源和系统环境特点的基础上,详细讨论了应用在荧光光纤传感器中微弱荧光信号检测电路的结构、特点和设计注意事项.     

基于伪随机序列的聚合物光纤微弱光信号检测

提出了一种利用FPGA发出的伪随机序列检测微弱光信号的方法。用伪随机序列调制LED或LD光源,注入测量光纤,输出光信号经过光电转换后与伪随机序列的调制信号做相关检测。由于伪随机序列具有与白噪声相近的相关特性,测量过程中的干扰、噪声对相关峰值影响很小。因此,可以检测到微弱的输出光信号,提高了测量精度。测量系统由LabVIEW虚拟仪器实现。     

双通道光纤气压传感器的光电信号检测及处理技术

众所周知,传感器(transducer)即为现阶段的前沿技术,亦为近年来科学发展的一个标志。若将计算机视为人类思维的扩展,那么传感器即为人类的感官,在计算机技术全面进程时,我们逐渐意识到信息摄取设备——传感器并未跟上信息技术的发展。而近年来,世界各国都逐渐侧重于传感器的开发,因此近年来传感器发展也非常迅速,二零零五年至今,传感器的产量与市场需求年增长率超过十个百分点。文章将以浅析双通道光纤气压传感器的光电信号检测及处理技术作为切入点,在此基础上予以深入的探究,相关内容如下所述。     

微弱光信号检测系统的研究北大核心

为了解决光电检测系统检测微弱光信号时的噪声问题,通过建立等效电路模型,推导出了光电检测电路输出信噪比公式并分析了影响系统噪声性能的关键因素。设计了一种可探测微弱光信号、具有宽动态范围和自动换档功能的光电检测系统。实验结果表明,该系统可对微弱光信号进行精确探测。     

微弱光信号检测电路的设计

从微弱光信号检测电路的设计方案入手,论述了光电检测电路的基本工作原理,给出了采用AD795KN为前置放大器来设计放大电路、有源滤波电路以及主放大电路．最终设计低噪声光电检测电路的一般原则。实验表明,基于本设计的检测电路可以有效测量微弱光信号,适用于一般光信号和微弱光信号的检测需要。     

基于伪随机序列的微弱光信号检测

 提出了一种测量微弱光信号的方法,用伪随机序列调制光源,调制后的光信号注入测量系统,输出光信号经过光电转换后与伪随机序列进行相关检测,由于伪随机序列具有与白噪声类似的相关特性,测量过程中的干扰和噪声对相关函数峰值影响甚小,相关检测显著提高了输出信号的信噪比,可以检测到微弱的光信号.文中理论分析了伪随机序列相关检测性能,并给出了实验测量结果.理论和实验结果都证明这种方法用于微弱光信号测量系统,在较强噪声背景下(信噪比-15dB),可以提高信噪比约30dB,有效地提高了测量精度.     

光纤光栅传感器检测技术

阐述了光纤光栅传感器的波长移动检测技术的发展现状,分析各种检测技术的原理和性能,并对增益光纤在FBG传感网络有源检测中的应用进行探讨。     

Optimum distributed detection of weak signals in dependent sensors

Locally optimum (LO) distributed detection is considered for observations that are dependent from sensor to sensor. The necessary conditions are presented for LO distributed sensor detector designs. and a locally optimum fusion rule for an N-sensor parallel distributed detection system with dependent sensor observations is given. Specific solutions are obtained for a random signal additive noise detection problem with two sensors. These solutions indicate that the LO sensor detector nonlinearities, in general, contain a term proportional to f'/f, where f is the noise probability density function (pdf). For some non-Gaussian pdf's, the new term is significant and causes the LO sensor detector nonlinearities to be nonsymmetric even for symmetric pdfs. LO solutions are presented for finite sample sizes, and the solutions for the asymptotic case are discussed. These results are extended to yield the form of the solutions for the N-sensor LO random signal distributed detection problem that generalize the two-sensor results     

关于光纤传感器测弱磁场的最高分辨率问题

本文根据实测的数据,采用较严格的分析方法,详细讨论了光纤传感器测弱磁场可达到的最高分辨率问题。     

Detection of weak signals in non-Gaussian noise

A locally optimum detector structure is derived for the detection of weak signals in non-Gaussian environments. Optimum performance is obtained by employing a zero-memory nonlinearity prior to the matched filter that would be optimum for detecting the signal were the noise Gaussian. The asymptotic detection performance of the locally optimum detector under non-Gaussian conditions is derived and compared with that for the corresponding detector optimized for operations in Gaussian noise. Numerical results for the asymptotic detection performance are shown for signal detection in noise environments of practical interest.     

光纤传感器

本文介绍了光纤技术的一个新的应用领域——光纤传感器的研究现状。分别介绍了各种传感型及传光型光纤传感器的基本原理、目前取得的结果、尚存在的问题以及可能的应用前景。     

Common path heterodyne optical fiber sensors

The common path type of differential heterodyne fiber-optic sensing scheme has been developed. It uses a polarization maintaining fiber as either a sensor or an optical lead and a dual-frequency dual-polarization laser beam. The sensing schemes are applied to the measurements of temperature, strain, force, pressure, rotation rate (gyro), magnetic and electric fields, and thin film thickness. The sensing scheme and main performances for each measurand are described. High precision and high stability as well as good linearity for each measurand are demonstrated     

Detection of weak random signals in IID non-Gaussian noise

This paper considers the detection of weak random signals in circularly symmetric, independent, identically distributed noise. Locally optimum detectors and ad hoc nonlinearities are considered, with asymptotic expressions provided for evaluation of detection performance. The analytical expressions are used to evaluate the robustness of detectors to mismatch in the noise models. Finite-sample Monte Carlo simulation results indicate the reliability of these asymptotic measures in cases of practical interest. The results show that, as has been found for detection of weak known signals in non-Gaussian noise, reasonably configured ad hoc nonlinearities are nearly optimum and robust to modest errors in the noise statistics     

Demodulated method of optical fiber stokes temperature sensors

The optical fiber temperature sensoris one of the dis-tributed measurement apparatus applied to the smartstructures of civil and military engineering.In the dis-tributedfiber Ramantemperature sensor ,the anti-Stokesand Stokes scattering radiation is sensi…     

光纤传感器的复用与数据融合

由于光纤传感器中存在交叉灵敏度,阐释传感器的测量及其相互关系是一个重要的课题。采用数据融合技术,对来自不同光纤传感器的信号进行综合处理,建立了分离光纤传感器中的时变耦合信号模型,即多光纤传感器的复用和数据融合的模型。在强度调制、时分调制、光栅调制和相位调制光纤传感器中,引入传感器、传感模型、复用和数据融合等四个层面的数据融合技术以分离时变耦合信号。     

Twisting and annealing optical fiber for current sensors

We demonstrate that twisting a fiber a few turns per meter before it is annealed largely eliminates the residual linear birefringence. This dramatically improves the yield of annealed coils used for current sensing and makes it possible to use fibers that previously had large residual linear birefringence. Twisting the fiber is effective because the residual birefringence, associated with core ellipticity, is reduced to near zero by twisting. A theoretical model of the twisted and annealed fiber current sensor is compared to experimental data. We also show good temperature stability for a sensor made with this new technique