共查询到20条相似文献,搜索用时 15 毫秒
1.
Theoretical analysis and experimental investigations are presented on the resolution of a ratiometric wavelength measurement system. Theoretical modeling indicates that the resolution of a ratiometric wavelength measurement system is determined by the signal-to-noise ratio of the input signal and the noise of the photodetectors associated with optical-to-electronic conversion. For experimental verification, a ratiometric system employing a macrobending standard single-mode fiber is developed and corresponding results are in good agreement with the theoretical prediction. 相似文献
2.
3.
本文依据普朗克黑体辐射定律,研究了光谱光电高温计的光谱波长和光谱带宽对温度测量准确度的影响,导出了温度测量误差关系式,并在钢铁热处理实验中进行了验证,介绍了减少外界环境对温度测量准确度干扰的几种实用方法,讨论了温度测量的方式所带来的不同测量误差,为钢铁工业测温正确使用光谱光电高温计提供了有用的参考。 相似文献
4.
激光波长作为“米”基准的重要实现途径之一,其量值准确性在计量校准、精密测量以及光谱探测等领域具有十分重要的意义。目前基于标准物质吸收谱线的波长基准仅能用于单一波长的计量校准,对于宽带光源波长校准手段有限。本文开展宽带连续调谐激光波长校准技术研究,利用飞秒激光频率梳宽光谱、光频可溯源至原子频率标准、稳定性高的特点,对宽带调谐光源在调谐输出时的连续光波长进行测量,最终实现了1 nm带宽下可调谐激光器调谐输出过程中瞬时值的测量,并利用该结果对可调谐激光器在121 GHz带宽的调频非线性度进行了评价。 相似文献
5.
Bandpass filters for wavelength division multiplexing-modification of the spectral bandwidth 总被引:5,自引:0,他引:5
Baumeister P 《Applied optics》1998,37(28):6609-6614
Dispersion of the phase shift upon reflection of the reflectors is used to narrow the spectral bandwidth of an all-dielectric bandpass filter for wavelength division multiplexing. The bandwidth is altered by the shifting of the order numbers of the spacer layers (of multiple half-wave optical thicknesses). 相似文献
6.
7.
针对某些传递损失较大的消声器,现有白噪声测试设备的单一噪声源发生器无法满足消声量的测试需求。通过采用低频和中频两种声源发生器,利用过渡管道与测试管道垂直连接的方式,实现了两种声源组合发声对消声器声学性能的测试。为了解决过渡管道与组合声源系统连接处声阻抗变化,导致输出的噪声信号频谱特性随机波动的问题,提出了一种噪声信号的修正方法。该方法基于四传感器法测量过渡管道声阻抗,根据过渡管道传递矩阵,以随机白噪声为激励源输出的管口噪声作为输出声压信号,得到组合声源系统的输入声压信号,实现了对组合声源系统声音信号的补偿。实验结果表明,与传统均衡器调节方法相比,该方法能够在较宽的测试频率范围内输出平稳的声压信号;其次,利用修正前后的声学信号对扩张腔的传递损失进行测量,修正后得到的测试曲线与理论值吻合度较高,证明了该方法的可行性。 相似文献
8.
Ahn TJ Moon S Kim S Oh K Kim DY Kobelke J Schuster K Kirchhof J 《Applied optics》2006,45(32):8238-8243
A new bandwidth measurement technique for a multimode optical fiber (MMF) using a frequency-domain intermodal interferometer is proposed. We have demonstrated that the relative modal delay (RMD) of a MMF can be obtained easily and accurately based on an optical frequency-domain reflectometry (OFDR) technique by using an intermodal interference signal among the excited modes of a MMF. As an example, a photonic crystal fiber with a few modes is prepared and its RMD is measured by using our proposed measurement technique. Measurement results are compared with those from a previously reported frequency-domain method. We have also measured the RMD of a commercial MMF as a practical application and compared our result with the one obtained from a well-known time-domain differential mode delay measurement technique. 相似文献
9.
10.
Zhu Y Sugisaki K Okada M Otaki K Liu Z Kawakami J Ishii M Saito J Murakami K Hasegawa M Ouchi C Kato S Hasegawa T Suzuki A Yokota H Niibe M 《Applied optics》2007,46(27):6783-6792
Two basic types of interferometer, a point diffraction interferometer (PDI) and a lateral shearing interferometer (LSI) suitable for operation in the extreme-ultraviolet (EUV) wavelength region, are described. To address the challenges of wavefront measurement with an accuracy of 0.1 nm rms, we present a calibration method for the PDI that places a mask with two large windows at the image plane of the illumination point light source and a general approach to deriving the phase-shift algorithm series that eliminates the undesired zeroth-order effect in the LSI. These approaches to improving the measurement accuracy were experimentally verified by the wavefront measurements of a Schwarzschild-type EUV projection lens. 相似文献
11.
12.
13.
多光谱BRDF测量系统转角装置研制 总被引:1,自引:1,他引:1
文中介绍了国内外双向反射分布函数的四种测量方案。采用固定光源和使样片转动以及探测器移动的方法实现了对双向反射分布函数的测量,进一步提出了利用可调机械臂结构以及三台步进电机的协调驱动实现对目标材料的高精度半球空间反射特性测量的改进方法。研制了多光谱双向反射分布函数测量转角装置,该装置的应用使双向反射分布函数测量系统的布局更合理,测量准确度更高。转角装置的探测臂旋转范围±180°,样片夹持台转动范围360°,角分辨率均为0.036°。经误差分析,所研制装置的转角精度约为0.75﹪。 相似文献
14.
The X-ray diffractometer method applied to the measurement of elastic stresses in mild steel is described. Chromium and cobalt radiation have been used to investigate the effect of X-ray wavelength on the accuracy of the technique. Effects of elastic anisotropy and beam penetration have been considered. 相似文献
15.
16.
Raj A. Holmes W.S. Judah S.R. 《IEEE transactions on instrumentation and measurement》2001,50(4):905-909
A technique for measurement of complex permittivity of dielectric materials, using coplanar waveguide cells is presented. A complete solution of the forward and inverse problems, based on a quasi-TEM propagation model, is given. Unlike other methods, our method allows solution of the inverse problem without the use of iterative or graphical techniques. The model accounts for the various discontinuities along the line. Several advantages result from this approach. Measurement over a broad frequency range is possible, limited only by dispersive effects. It is suitable for solids not amenable to machining for cavity measurements, and there need not be any contact 相似文献
17.
A. G. Ramazanova 《Measurement Techniques》1991,34(12):1234-1236
Translated from Izmeritel'naya Tekhnika, No. 12, pp. 23–25, December, 1991. 相似文献
18.
文章以可见分光光度计主标准装置之一的干涉滤光片对上海第三分析仪器厂生产的721型分光光度计检定为例,进行波长示值误差测量不确定度评定。 相似文献
19.
20.
L. YU P. K. DAS N. D. P. BARLTROP 《Fatigue & Fracture of Engineering Materials & Structures》2004,27(1):51-58
A new attempt is made in this paper to quantify the effect of bandwidth and non‐normality in fatigue damage analysis. For the lack of actual stress history, a series of non‐Gaussian and homogeneous random processes are generated with fast Fourier transform (FFT) acceleration. A factor is defined on the basis of rain‐flow counting and Palmgren–Miner rule to correct the narrow band and normality assumption. It is revealed that the fatigue damage evaluated through the traditional method may be either conservative or rather unconservative. The upper and lower bounds of the correction factor are studied with respect to kurtosis and skewness of the generated random process and the slope of S–N curve. 相似文献