位相测量轮廓术中相移误差和最佳相移次数的研究

位相测量轮廓术是三维面形测量的一种重要方法,它采用的离散相移技术要求精确的相移,在实际系统中不可避免地存在着相移误差,它将导致计算位相和重建面形的误差,本文利用已建立的三维面形仿真系统,定量研究了不同线性相移误差下所引起的位相误差和面形误差大小,本文还讨论了应如何选取最佳的相移次数,本文的工作可为实际测量的校准提供理论数据,对实际测量工作具有指导意义。     

基于起始触发相位调整的三角波线性度测试方法研究

为解决信号模拟器专用测试设备三角波线性度的测试标定需求,提出一种基于起始触发相位调整的三角波线性度测试方法。以设备外触发输出作为基准,通过调整三角波的起始触发相位,将三角波的上升沿或下降沿进行梯级水平切割,采用数字示波器和数字电压表组合方式进行监视和测量不同梯级的电压,利用最小二乘法计算出三角波上升沿或下降沿的线性度,并对测量结果的不确定度进行分析评定。测量结果比对表明,设计的三角波线性度测试方法切实可行,能推广应用到函数发生器三角波线性度的测试,具有很好的实用性。     

"测量不确定度"应用研究初探

一、前言测量不确定度是建立在现代误差理论基础上的新概念,其理论体系是对经典误差理论的充实和完善。在全球经济和市场激烈竞争的今天,测量不确定度的研究和统一是进行国际贸易和技术交流所必不可少的,这一观点已逐渐被各层次的计量工作者所认同。因此,对国际公认的权威性文件——《测量不确定度表示导则则501993（）的研究、推广、采用也受到了各国计量工作者的高度重视。为适应科研、生产发展形势的需要,我们于1996年以科研课题的形式开展对“测量不确定度”的应用研究,探讨和摸索在工业企业的测量领域中如何采用实施旧01993（E…     

相位计示值误差测量不确定度评定

文章从测量方法、数学模型、不确定度传播律,以及不确定来源、分量等介绍了相位计示值误差测量不确定度评定程序,并给出了其结果的报告形式。     

基于彩色编码相移条纹的相机标定

针对传统标定方法对靶标特征点模糊噪声适应性低的问题,提出一种基于彩色编码相移条纹的标定方法.以液晶显示面板为标定靶,依次显示水平和垂直彩色编码相移条纹;通过颜色通道分离,得到正交相移条纹;结合相移理论,以正交相位截断线的交点为特征点;多次改变靶标位姿,提取特征点,结合基于平面二维靶标的标定理论,实现单相机与双目立体视觉...     

相位计测量不确定度评定

根据JJG381-86《BX-21型低频数字相位计检定规程》,介绍了相位计测量原理,给出了相位计测量不确定度的评定方法。     

高频光电导少子寿命测试仪校准方法

文章介绍了高频光电导少子寿命测试仪的原理、结构以及计量特性,并给出高频光电导少子寿命测试仪的校准方法,同时对测量结果的不确定度进行了评定。     

关于典型相位噪声测量技术的应用研究

相位噪声是评价无线电信号纯度的重要研究内容,随着各类频率信号生成设备的快速发展,对相位噪声测量技术提出更多应用需求和更高的技术要求,出现不同的测量方法,为熟练掌握不同测量方法的原理和具体应用场景,开展直接频谱仪法、鉴频器法和相位检波器法三种典型相位噪声测量方法的应用研究,以相位检波器法为例建立测量方法模型进行理论推导,详细分析基于相位检波器法的相位噪声测量不确定度来源,计算得到测量标准不确定度和扩展不确定度,同时针对不同方法进行重复性测试,已基于相位检波器法的相位噪声测量不确定度分析为例计算分析不同方法的测量不确定度,论证典型相位噪声测量方法的优缺点,提出方法择选方案,为相位噪声测量技术应用提供参考。     

四步相移数字全息干涉术相移提取和物光重建

提出广义相移干涉术中结合广义四步公式改进最小二乘法抽取任意相移进而重建复波的方法.利用广义相移数字全息算法的物波重建公式替代传统最小二乘法来提取参考光相位和重建物体波前,大幅减小迭代循环的计算量.使用该方法,每一次迭代计算参考相位只需要一个最小二乘法,同时利用物波前重建公式计算物光相位.这种方法的可行性和有效性已被计算...     

高频电刀测量不确定度评定

文章讲述高频电刀测量不确定度评定与结果。     

Design and analysis of compact work-recovery phase shifter for pulse tube refrigerator

This paper proposes and describes a compact work-recovery phase shifter of a pulse tube refrigerator. Most pulse tube refrigerators recently developed utilize a long inertance tube and a reservoir for phase control between dynamic pressure and mass flow rate at the cold-end of pulse tube refrigerators. An inertance tube-type phase shifter (long inertance tube and reservoir), however, sometimes creates a problem of compact packaging in cryocooler applications and dissipates the work transferred from a compressor as heat. To overcome this disadvantage, an inertance tube-type phase shifter is replaced with a compact work-recovery phase shifter composed of a mass–spring–damper system and a linear generator in a pulse tube refrigerator. This process is achieved by using analogy of the inertance tube-type phase shifter and the mass–spring–damper system. This paper describes a specific configuration of the designed compact work-recovery phase shifter. Using the simulation code, the performance of the pulse tube refrigerator with the compact work-recovery phase shifter is estimated. As a result, the pulse tube refrigerator with the compact work-recovery phase shifter has the comparable cooling capacity with the pulse tube refrigerator with the inertance tube-type phase shifter. If the recovery work is properly utilized, it can also achieve higher efficiency than that of the pulse tube refrigerator with a typical inertance tube-type phase shifter. In this paper, the parametric study of the mass, the spring and damper coefficients of the compact work-recovery phase shifter has been done and their effects are specifically evaluated.     

适用于离焦状态相机的相位编码标定方法

现阶段通用的相机标定方法需要使用者提供准确的标定板特征点像素坐标。但对某些成像位置特殊的相机而言,一般标定物(如长宽在厘米级别的标定板)的使用范围在其清晰成像范围之外。使用这些相机拍摄一般标定物,只能得到离焦的模糊图像,无法准确提取特征点像素坐标。本文分析了光学系统离焦状态对基于正弦光栅的结构光(简称正弦结构光)相位的影响。利用正弦结构光相位与相机对焦状态无关的性质,提出了一种利用相移法正弦结构光编码的方法,对标定物上特征点进行相位编码,实现了相机在离焦状态下的标定。经过实验验证,标定结果焦距长度与真实值之间最大偏差为0.47%,最大像素重投影误差为0.17 pixels。该方法为具有特殊成像范围的相机的标定提供了一种解决方案。     

Failure analysis of the adhesive joint of microwave ferrite phase shifter

Failure investigation is carried out on the adhesive joint of microwave ferrite phase shifter. Though, practically, the failure mode of microwave ferrite phase shifter can be described as the fracture of adhesive joint between ferrite and microwave dielectric ceramic, the failures of adhesive layer could be found in various ways and at various stages of manufacture, assembly and service. They may be due to the strength degradation caused by moisture environment, or the voids defects originated from dehydration effect of the adhesive as well as the contamination during manufacturing. With the help of SEM, FTIR and TGA, both the normal and failed samples of microwave ferrite phase shifter were selected, compared and analyzed. Recommendations for the structural design and the adhesive process are presented, and the responsibility of the failures was charged to the negligence of the manufacturer of the microwave ferrite phase shifters.     

Global analysis of the phase calibration operation

A global approach to phase calibration is presented. The corresponding theoretical framework calls on elementary concepts of algebraic graph theory (spanning tree of maximal weight, cycles) and algebraic number theory (lattice, nearest lattice point). The traditional approach can thereby be better understood. In radio imaging and in optical interferometry, the self-calibration procedures must often be conducted with much care. The analysis presented should then help in finding a better compromise between the coverage of the calibration graph (which must be as complete as possible) and the quality of the solution (which must of course be reliable).     

温度计修正值不确定度评定方法的改进研究

"JCGM 100:2008"的温度计修正值不确定度评定案例中,模型为bt=y1+y2(t-20),自变量(t-20)与因变量修正值bt=(tR-t)间不独立,实质上选温度计示值t作自变量、标准值tR作因变量,前者的误差影响显著大于后者,这与应选误差影响可忽略的作自变量的原则相悖.案例中评定b(t′)的不确定度ubt′错用了求预测值置信区间的预测模型,应先改用tR作自变量拟合、再求反预测值tR(t′)及其置信区间的校准模型,我们在预测和校准两种情况下计算了ubt′以作比较.案例中limn→∞ubt′=0有逻辑性瑕疵.对自变量等距分布、自变量在区间两端集中各半这两种情形,算出其斜率标准差的期望值之比约槡3,否证了"测散布数据最小二乘拟合主要为减小因变量的独立同分布随机误差影响"的命题,初步导出"主要为减小因变量的具有随机性的未定系差分量影响"的推论,质疑了高斯-马尔科夫假定的普适性.考虑因变量标准差包含两类分量,提出了预测或校准(反预测)模型下的置信区间的调和近似算式.     

Monolithic HTS microwave phase shifter and other devices

We describe a monolithic high-temperature superconductor (HTS) phase shifter based on the distributed Josephson inductance (DJI) design integrated monolithically into a 10-GHz microstrip line. This microwave circuit incorporates >1000 HTS rf SQUIDS. Recent data demonstrate the performance of this broadband HTS circuit. We observed phase shifts greater than 150° in resonant structures, and 20° in broadband circuits. The nonlinear inductance of the superconducting transmission line can be used for other novel applications, including parametric amplification. A comparison of the DJI circuit to a series array of Josephson elements (used for pulse sharpening) will contrast these two new and exciting nonlinear transmission line circuits.