在片LRRM校准算法研究

研究了LRRM(传输线-反射-反射-匹配负载)校准算法,完善了负载标准测量模型,通过参考面平移将测量结果由被测件中间平移到探针端面,基于MATLAB开发平台编制了校准软件.用研究的校准方法和商用校准方法分别对同一在片散射参数测量系统进行校准,校准后的系统测量相同的短路标准和衰减器.测量结果显示,在100 MHz～110...     

计量标准测量不确定度验证的考核方法

计量标准的测量结果不确定度是指在规程规定的条件下．用该计量标准对典型的被检定(或校准)对象，进行检定(或校准)时所测得结果的不确定度。计量标准测量结果不确定度的评定结果直接影响到验证结论。在《规范》附录C中推荐了三种不确定度的验证方法，三种方法对验证结果的判定都离不开所评定的测量结果。     

63650/Д-011型螺旋桨毂整流罩平衡试验台测量结果的不确定度评定

从63650/Д-011型螺旋桨毂整流罩平衡试验台(以下简称试验台)需要校准的实际出发,充分利用现有测量标准,提出可行的校准方法,并通过对测量不确定度的来源分析,各项标准不确定度的评定,对合成不确定度的评定结果进行综合分析,从而验证采用的校准方法的合理性。     

仪器自校的可能性与实施的探讨

对实验室广泛采用的测量设备的"自校"给出一个明确的定义,从规定自校准的标准器、编制自校准的作业指导书、进行自校准测量数据的测量不确定度评定和校准人员的培训等4个方面规范实验室的自校准工作,以保证量值溯源的可靠性,使得自校准工作真正能够起到量值溯源的作用.     

流量现场校准装置测量误差分析及修正

从流量现场校准装置的结构和测量方法入手,对校准装置的测量误差进行了分析,并根据分析结果对校准装置的测量结果进行了误差修正。通过试验对修正结果进行了验证。验证结果表明,通过测量误差的修正,校准装置的流量测量相对误差可以满足系统设计指标的要求。     

宽带在片SOLT校准件研制及表征

针对在片S参数校准,设计制作GaAs衬底SOLT校准组件,通过计算方法对校准组件中直通、开路、短路和负载校准件中偏置传输线的时延和损耗进行定义,运用基于NIST multiline TRL校准的测量方法对校准组件中开路校准件电容和短路校准件电感参数进行提取,结合直流电阻测试法测试负载阻值大小,实现对SOLT校准组件的完整表征。最后用自行研制并表征的SOLT校准组件校准在片S参数测试系统,通过测量无源器件验证校准效果,将测量结果与NIST multiline TRL校准后的测量结果比较,在20 GHz内传输幅度最大偏差0.1 dB,传输相位最大偏差3.5°。     

纳米力学测量系统的载荷与位移溯源校准方法研究

对纳米力学测量系统在准静态压入模式下的载荷因子、位移因子的量值溯源校准方法进行了研究。通过一组标准砝码产生标准载荷,拟合标准砝码质量和传感器输出电压得到载荷因子;利用激光干涉仪测量压针位移,拟合干涉仪位移值和传感器输出电压得到位移因子。采用标准样品对校准结果进行了试验验证,校准后的纳米力学测量系统在国际比对测量中取得了良好结果。     

射线图像分辨力测试计的校准方法

近年来,射线图像分辨力测试计在工业无损检测和医学诊断仪器校准中的应用日趋广泛。射线图像分辨力测试计作为测量图像分辨力的专用标准器具,目前国内尚无可依据的计量检定规程/校准规范对其计量性能进行控制。文章详细介绍了射线图像分辨力测试计的校准环境、校准设备、技术指标要求、校准项目和校准方法等,并通过校准实例分析和测量不确定度评定对校准方法进行了验证。提出的校准方法为射线图像分辨力测试计的校准工作提供了参考。     

对向测量皮托管的国际比对

为验证现场烟道流量测量使用的对向测量S型皮托管、球形三维皮托管和棱形三维皮托管校准系数的一致性,中国计量科学研究院(NIM)主导开展了包括美国国家标准与技术研究院(NIST)和韩国标准科学研究院(KRISS)参加的皮托管校准比对。比对结果表明:S型皮托管在不同实验室间比对结果吻合度相对较差,不适合作为比对标准器;球形三维皮托管在不同实验室间比对结果吻合度高于棱形三维皮托管,流速校准系数差异对测量轴向流速的影响高于偏航角参考位置偏差与俯仰角校准系数差异造成的影响;皮托管的偏航角参考位置偏差和俯仰角校准系数差异造成的轴向流速差异在0.03%~0.9%,由于流速校准系数差异造成的轴向流速差异在1.9%~12.2%。     

谈校准与校准周期

一、核准的对象是广泛的校准是在规定条件下为确定测量仪器或测量标准或标准物质所提供的量值与相应的由参考标准确定的量值之间关系的一组操作。据此定义,校准与检定相似,同是确定测量设备计量特性是否符合规定要求的手段。《标准》没有“检定”这个词及定义,有的只是“校准”。校准不仅是GB／Tlop22．l标准（以下简称《标准》）的关键术语,也是国际计量界常用术语。IS0opl标准第“4．112”条第“b”款规定“确认影响产品质量的所有检验。测量和试验设备,按规定的周期或使用前对照与国际或国家承认的有关基准有已知有效关系鉴定合格…     

110 GHz在片16项误差模型校准件定值方法研究

现有商用集总参数校准件电路模型使用简便,但由于校准件电路模型的不完善、电路中参数在提取过程中采用拟合算法等原因,导致其定值准确度受限。从用于高频串扰修正的16项误差模型校准件设计入手,给出了校准件高精度的定值方法--即通过研制辅助的Multiline TRL校准标准,采用测试加仿真的方式对校准件进行定值,并采用定值文件作为定值样式。采用定值过的16项误差模型校准件校准在片测试系统,并与美国NIST基于Multiline TRL的二次校准方法比较,在110GHz内,两者S21相差在0.30dB以内,相位相差1°以内。所不同的是,16项误差模型校准件的个数远低于NIST,并且在校准过程中不需要移动探针。在保证准确度的前提下,大大提高了测试效率。     

15-term self-calibration methods for the error-correction ofon-wafer measurements

An improved method of network analyzer calibration is described using the 15-term full model which includes all leakage errors between on-wafer probe tips. This model is well suited to eliminate measurement errors of network analyzer measurements on the wafer. All procedures presented are so-called self-calibration methods, allowing for standards that are not completely known. This allows one to create calibration standards in an easy way and to monitor the calibration process. Simple and robust closed-form equations are presented for all procedures. All procedures can be derived from the general method MURN (match, unknown, reflect, network). The MORN (match, open, reflect, network) is presented, which is particular interesting for on-wafer-measurements. Furthermore, the TMRN (through, match, reflect, network) procedure presented is especially designed for coaxial measurement problems. Experimental results of the TMRN method attest to the very good accuracy and viability of the 15-term self-calibration procedures and can be compared with other 15-term procedures     

无源器件在片散射参数校准比较方法研究

为解决由于不同校准方法导致无源器件在片散射参数测试结果存在偏差的问题,通过以校准准确度高的多线TRL校准方法为参考基准,比较SOLT、LRRM校准方法与其误差项的差异.充分考虑了两个端口误差项的级联关系,推导得到误差项差异的数学模型,通过参数转换计算得到无源器件在片散射参数的最大偏差.在100MHz～67GHz频段范围...     

双视角三维测量系统同时标定方法

针对现有标定方法在相机无公共视场情况下的局限性,本文提出使用双平面标定板对双相机进行同时标定的方法。通过推导两个相机与两个标定板间的坐标变换,将待标定相机与参考相机的相对位姿关系的求解转换为较为成熟的手眼标定方程求解。通过实验验证:该方法可实现双相机的同时标定,且方法的绝对误差不超过0.089 mm,较为可靠;在双视角三维测量系统中,与相位-深度的累积误差不超过0.116 mm,可为进一步的数据融合提供可靠的初值。此外,由于本方法灵活方便,可适用于多视角三维测量系统的同时标定。     

A new robust method for six-port reflectometer calibration

A new robust method for finding the parameters of Engen's six-port-to-four-port reduction algorithm for six-port reflectometer calibration has been developed. Like other previously published methods, it uses a minimum of five loads with an unknown but constant absolute value of the reflection coefficient and unknown but well-distributed phases. However, the quality of the parameter estimates is improved, especially in noisy environments, by efficiently eliminating cases in which these earlier methods may become ill-conditioned. The new method has been used successfully to calibrate a newly developed six-port reflectometer in GaAs MMIC technology working between 1.3 GHz and 3.0 GHz     

Results of network analyzer measurements with leakageerrors-corrected with direct calibration techniques

Exact calibration procedures to correct two-port measurements with leakage errors are developed for a network analyzer having three or four measurement channels. Many measurement systems including open air devices, such as MMIC wafer probes, contain numerous crosstalk paths which are included in the full models of the direct calibration procedures. These novel 15-term and 22-term procedures are based on closed solutions and need five and six successive measurements of completely known calibration standards. First, both procedures solve these general error models exactly. The reduction of the common 22-term model to a 10-term model describes a network analyzer with three measurement channels in a simple and common manner. In this way one may create a great number of new calibration procedures. The sensitivity and accuracy of a direct 15-term and a direct 22-term error correction procedure is demonstrated by experimental results     

Variable selection for neural networks in multivariate calibration

The problem of variable selection for neural network modeling is discussed in this paper. Two methods that gave the best results in a previous comparative study are presented. One of these methods is a modified version of the Hinton diagrams, the other method is based on saliency estimation and is part of the Optimal Brain Surgeon algorithm for pruning unimportant weights in a neural network. We also propose two new methods, based on the estimation of the contribution of each input variable to the variance of the predicted response. These new methods are designed for situations where input variables are orthogonal, such as the PC scores often used in multivariate calibration. The four methods are tested on synthetic examples, and on real industrial data sets for multivariate calibration. The main characteristics of each method are discussed. In particular, we underline the strong theoretical and experimental limitations of methods like the modified Hinton diagrams, based on weight magnitude estimation. We also demonstrate that although the saliency estimation approach is theoretically more stringent, it gives unstable results on repeated trials. The advantage of the two variance-based approaches is that they are much less dependent on the initial weight randomization than the two other methods, and therefore, the results they produce are more stable and reliable.     

一种对在片测量系统中串扰误差进行修正的新型校准方法

现有高频段在片S参数校准方法有16-term误差模型校准方法和基于多线TRL的二次串扰修正算法,它们对测试系统之间的串扰误差进行了较好的表征。提出了一种新型校准方法,即把测试系统之间的串扰等效为一个与被测件并联的二端口网络。整个校准方法一共分为两步,第一步采用常规的SOLR校准方法得到基本8项误差模型,第二步通过测量一个串扰标准件(可以是SOLR中的开路校准件)完成对串扰误差的表征。仿真和测试结果表明,新型校准方法准确度可达到16-term误差模型的准确度,并对串扰误差具有相当的抑制效果。同时,新模型方法只需使用4个校准件,数量少于传统16-term误差模型方法,在保证准确度的前提下,提高了测试效率。