基于探测器的成象光谱仪绝对辐射定标方法

用一组窄带滤光片、简易辐亮度计和硅光二极管探测器设计了绝对型光谱辐亮度计。精确测量滤光片的光谱透过函数，计算辐亮度计的视场，标定探测器的绝对光谱响应度，成为绝对光谱辐亮度计，用来标定成象光谱和其它光学遥感器，并与基于光谱辐照度灯进行辐射定标的传统方法进行了比较。结果表明，基于探测器进行辐射定标的方法是一种提高光学遥感器定标精度的途径，而且是佐证其它定标方法可靠性的一种手段。     

高速窄带多光谱成像系统光谱重建技术研究

光谱成像技术可以同时从光谱维和空间维上获取被测目标的信息，即结合了空间成像系统和光谱检测系统的功能，因此近年在影像获取与处理领域中倍受重视。本论文基于窄带多光谱成像技术建立八通道CCD多光谱成像系统，它能够实时采集八个通道的图像，获得波长分布从可见到红外（420-940nm）八个波段的光谱响应值。在此基础上对图像进行位置配准、反射率定标、采用插值算法获得其它波段光谱响应值，最终能够获取图像中任意一点的光谱反射率及颜色参数。实验结果表明，本文使用的三次样条插值法对原始光谱图像进行平滑操作的方法是有效的，能够以一定精度模拟出目标物点的真实光谱特性。该系统在动态目标检测识别、艺术品评价复制等领域有着广阔的应用前景。     

一种双光束自动测试光栅绝对与相对光谱衍射效率的原理性方案

提出了一种快速自动测试光栅光谱衍射效率的新方法。重点推导了测试平面光栅绝对光谱衍射效率与相对光谱衍射效率公式，介绍了双光束高精度自动测试光栅光谱衍射效率曲线的基本原理、方案与方法，并分析了测试精度。研究表明，本方案的测试速度和精度均比一般测试方法提高一倍，并能有效地消除光源波动对测量结果的影响，测量误差小于５×１０－３。     

光谱透射比基标准的发展概况

本文介绍了光谱光度学的基本任务与内容，概述了这一计量分支的国际学术活动情况。重点讨论了光谱规则透射比基准的现状与量值比对结果，指出了傅立叶变换红外光谱仪在光谱测量仪器中的重要性，及其量值的溯源性和国际等效性的紧迫感。     

共轭聚合物—聚对苯撑乙烯齐聚物的合成及发光性质的研究

以Ｗｉｔｔｉｇ反应的方法，分别合成了五种聚对苯撑乙烯（ＰＰＶ）齐聚物，并用红外光谱、核磁共振、紫外－可见光谱及荧光光谱对所得齐聚物进行了测试和表征，发现它们的溶解性能有所改善，紫外可见光谱均向红移。     

硅光电探测器光谱响应度测量标准装置

本文介绍了硅光电探测器光谱响应度测量的原理和装置，描述了相对和绝对光谱响应度标定方法，详细分析了引起标定误差的因素和误差合成，简要分析了国际比对结果。本装置的波长范围为３００￣１０００ｎｍ，相对光谱响应的不确定度（１σ）为０．２１％￣０．８６％，绝对光谱响应的不确定度（１σ）为０．２５％￣０．８７％。     

光谱增感机理的介绍

回顾了染料光谱增感机理的发展过程，着重阐述了电子传递与能量传递两大机理以及根据这两个经典机理来设计新的光谱增感染料，同时也介绍了当前的光谱增感理论微观研究的发展。     

多波段水下光谱辐射计

研制了基于干涉滤光片分光的船载多波段水下光谱辐射计，该辐射计可同步观测12波段下行光谱辐照度、12波段上行光谱辐照度和7波段上行光谱辐亮度，水下剖面测量深度达200m。在水槽中测定了辐照度探头的余弦响应特性和浸没因子，利用MonteCarlo方法模拟了阴影误差分布，给出了仪器的主要性能指标。给出了与Macam公司SR9910c型水下光谱仪的比对结果以及海上试验数据的分析结果。     

拉曼检测仪器用干涉滤光片综述

介绍了拉曼检测仪器用干涉滤光片（简称拉曼滤光片）的应用场景和功能，研究分析了其光谱指标对拉曼检测仪器性能和精度的影响，包括光谱透射率、光谱反射率、背景截止度、截止陡度等。为满足拉曼滤光片光学指标的精准光谱测试需求，推荐了分光光度计测试及相关测试参数的设置方法。此外，还介绍了采用溅射镀膜工艺制造高性能拉曼滤光片的方法及优势。最后，对拉曼滤光片的发展进行了总结和展望，为拉曼滤光片在科学研究和产业化应用中提供参考。     

光干涉型甲烷测定器产生光谱漂移的原因

甲烷测定器是煤矿企业安全生产必不可少的测定仪器，光干涉型甲烷测定器在使用过程中产生的“光谱漂移”问题，直接影响甲烷测定精度。该文解析其工作原理，罗列了光谱自动漂移的种种现象，分析其影响因素并对防止光谱漂移提出具体的措施。     

Non-uniform Sampling in Optical Processing

The use of non-uniform sampling in optical processing is considered. The filtering operations needed to recover the spectrum of a non-uniformly sampled band-limited function are examined. Serious limitations are shown to exist for markedly non-uniform sampling.     

Sampling 3-D seismic data

A 3-D seismic survey is usually achieved by recording a parallel profile network. The 3-D data thus obtained are sampled and processed in a cubic grid for which the sampling requirements are generally derived from the usual 1-D viewpoint. The spectrum of 3-D seismic data has a support (the region of the Fourier space in which the spectrum is not zero) that can be approximated by a domain bounded by two cones. Considering the particular shape of this support, we use a 3-D sampling theory to obtain results applicable to the recording and processing of 3-D seismic data. This naturally leads to weaker sampling requirements than the 1-D viewpoint does. We define the hexagonal non-cubic sampling grid and the triangular non-cubic sampling grid and show that fewer sample points are needed to represent 3-D seismic data with the same degree of accuracy. Thus, using the hexagonal non-cubic sampling grid we point out that the maximum value of the spatial sampling interval along the profiles is larger by 15.6% than the one of the cubic sampling grid. We also point out that the triangular non-cubic sampling grid requires a number of sample points equal to half the number required by a cubic sampling grid.     

FFT幅相联合的快速高精度频率估计方法

快速傅里叶变换（Fast Fourier Transform,FFT）常用于信号频率估计,采用填零的方法可降低幅度谱频率搜索间隔的量化误差,但是会使频率估计的计算量成倍增加。本文提出了一种FFT幅相联合的快速高精度频率估计算法,首先利用信号采样的频谱序列和尾首样本差确定幅度谱及峰值位置,然后由频谱序列在幅度谱峰值位置和信号采样的尾首样本差来确定频率搜索间隔的量化误差校正值。因此,所提方法同时利用了幅度谱峰值的位置信息与相位信息。分析结果表明,与仅基于幅度谱搜索的FFT算法相比,所提方法的计算复杂度更低,且定位精度更高。     

Signal spectrum analysis and period estimation by using delayedsignal sampling

The paper describes a signal power spectrum analyzer and a signal period estimator whose bandwidth is not limited by the mean sampling time. The procedure relies on the evaluation of the input signal autocorrelation function in different delayed time instants, located at either equispaced or random time instants. To do this, a recursive random sampling process in the time domain was used in order to avoid any bandwidth limitation due to the sampling strategy in the evaluation of each autocorrelation function. The signal power spectrum as well as its period, provided that an approximate value of the fundamental frequency is known, can finally be evaluated. Some theoretical background and experimental work are reported in the paper for validating the performance of the method     

Spectral analysis of a sampling optical time-domain reflectometer

A spectral analysis is presented for the backscatter signal of optical time-domain reflectometers (OTDR). Periodic spatial fluctuations in the fiber attenuation produce modulation sidebands in the frequency spectrum of the backscatter signal. Applying the sampling technique to OTDR leads to a considerable improvement of the signal-to-noise ratio (S/N) due to spectrum compression, as a tradeoff with the measurement time. It gives a performance equivalent to digital averaging. Design examples are given at wavelengths of 0.85, 1.3, and 1.55 μm. A practical setup of a sampling OTDR is described     

Application of basic splines for sampling multidimensional signals of finite duration

We investigate limitations of sampling theory for signals with finite spectra, which are particularly prone to appearance during measurements in multidimensional spaces. We present a method for sampling with several arguments, using basic splines. Fourier transforms, and the Parseval equality. We present an example of adaptive optimization of the sampling grid for a magnetic field that is associated with a spectrum of multidimensional signals having fractal similarity. Translated from Izmeritel'naya Tekhnika, No. 1, pp. 3–6, January, 2000.     

全相位频谱校正技术在水声通信中的应用研究

多普勒效应是影响水下移动通信性能的主要因素,准确估计多普勒频移对提高通信系统可靠性具有重要意义。在进行离散频谱分析时,时域非整周期截断会造成频域能量的泄漏,导致频谱估计精度降低。全相位频谱分析具有良好的抑制频谱泄漏特性及相位不变性。仿真验证了全相位频谱校正技术相对于传统频谱校正技术在估计性能上的优势,并在此基础上探讨了全相位频谱校正技术在水声通信中的应用。采用全相位频谱校正技术进行多普勒频移估计,进而进行多普勒补偿以降低通信系统误码率。仿真结果表明,全相位频谱校正技术能够实现高精度多普勒频移估计,从而提高水下移动通信系统的可靠性。     

结构动力可靠度计算的基于反应功率谱的重要抽样法

提出了受随机地震作用的结构动力可靠度计算的基于反应功率谱的重要抽样法。为了提高动力可靠度计算的效率,利用反应功率谱峰值点对应频率处输入激励幅值的变化对失效概率的影响,提出了利用反应功率谱增大输入激励幅值的方差,达到重要抽样的目的;根据随机振动理论,平稳随机反应功率谱曲线与频域内反应绝对值平方曲线的期望值是相似形,而频域内反应绝对值平方曲线的期望值可以通过Fourier 变换很方便的求出,所以也可利用频域内反应绝对值平方曲线的期望值增大输入激励幅值的方差;重要抽样密度函数可表示为幅值分量概率密度函数连乘的形式,其所采用的输入激励幅值的方差可通过少量的结构分析次数得出。通过对三自由度线性结构及十自由度随机结构的计算,表明该文算法是提高动力可靠度计算效率的有效途径,也是求解随机结构动力可靠度的有效途径。     

Self-reconstruction of wave packets due to spatio-temporal couplings

Abstract

The spatio-temporal self-reconstruction of the wave function fulfilling the wave equation is examined. The effect is based on the sampling of the spatial spectrum of the wave function in the cylindrical coordinates and on its coupling to the temporal frequency spectrum. The predetermined spatio-temporal profile of the wave function is approximately reconstructed at the periodic spatial intervals along the propagation direction for the continuous temporal spectrum. The periodicity appearing in both the spatial and temporal evolutions are examined for wavefields with the discrete temporal spectrum. The reconstructed field then simultaneously exhibits propagation properties known as the self-imaging and the mode-locking.     

Spectral recovery by analytic continuation in crossing-based spectrum analysis

By the use of analytic continuation, the correct spectrum of an undersampled analog input signal f(a) (t) of a true bandwidth B is recovered from an aliased Fourier spectrum that is computed directly from a data set consisting of sinusoid-crossing locations {t(i)}, where the signal f(a) (t) intersects with a reference sinusoid r(t) with a frequency of W 相似文献