EMC测量中的不确定度分析与评定

本文对EMC检定项目中的一项——电源端子连续传导干扰电压测试中的主要不确定度分量进行了详细的分析和评定,在计算过程中,作出了合理的简化和估计。     

EMC测量中的不确定度分析

文章对EMC检测项目中的一项——电源端子连续传导干扰电压测试中的主要不确定度分量进行了详细的分析和评定，在计算过程中，作出了合理的简化和估计。     

测量不确定度评定

本文根据1992年国际不确定度会议的讨论情况,介绍测量不确定度的评定方法。     

测量不确定度评定中的相关性

１ 什么是相关性？相关（ｃｏｒｒｅｌａｔｉｏｎ）指两个或多个随机变量分布内 ,各随机变量间的关系。相关是统计学中最重要的概念之一。从数学上来讲 ,相关是根据线性相关系数 ρ或其估计值ｒ来考虑的。ＪＪＦ１０５９—１９９９《测量不确定度评定与表示》２ ２２节对相关系数给出了以下定义 :相关系数是两个变量之间相互依赖性的度量 ,它等于两个变量间的协方差除以各自方差之积的正平方根 ,因此 :ρ（ｙ,ｚ）＝ρ（ｚ,ｙ）＝其估计值 :ｒ（ｙ，ｚ）＝式中ｖ为协方差 ,σ为总体标准偏差 ,ｓ为实验标准偏差 ,ｓ（ｙ,ｚ）为ｖ的估计值 ,称…     

不确定度评定实例分析 耐电压测试仪测量结果的不确定度评定

耐电压测试仪作为对各种电气设备、绝缘材料和绝缘结构等的抗电性能进行检测和试验的仪器,其使用已相当普遍.因此,对其在使用过程中的两个主要参数--输出电压值及击穿报警电流的测量结果不确定度进行评定非常必要.     

产品检验测量不确定度评定

产品检验是指带有观察和判断的合格评定,通过必要的测量、测试或检查而实现。根据合格评定的需要所进行的测量,有时称为检验测量。因此,产品检验是通过检验测量和合格评定来确定产品是否满足规定要求。如果对产品检验的合格评定,没有考虑不确定度的影响,就可能对合格评定结果带来误判。     

测量不确定度评定的注意事项

国家计量技术规范JJF1059-1999《测量不确定度评定与表示》具有普遍适用性，可对测量过程以及数据处理中产生的测量不确定度进行评定，为保证测量不确定度的评定质量，克服评定中易犯的错误，提出一些具体事项，请评定人员予以注意，以利推广测量不确定度的应用。     

心电图机电压测量的不确定度评定

心电图机电压测量的不确定度评定,分析测量过程中的不确定度主要来源,并量化分析,得到合成标准不确定度和扩展不确定度。     

电平幅度测量不确定度评定与分析

本文通过实例阐述了电平幅度测量不确定度的评定和分析,提出了充分利用仪器设备给出的影响电平幅度测量不确定度因素的有关技术指标,用不同的测量方法展开标准测量不确定度和扩展测量不确定度评定计算的比较,给出了针对电平幅度测量,可实现的测量不确定度最优化方法,具有一定的实用参考价值.     

EMC测量系统测量不确定度的评定

EMC(电磁兼容性)测试贯穿在产品的设计、开发、生产、使用和维护的整个周期,对评价产品是否达到电磁兼容性指标非常重要.EMC测量结果和由测量结果得出的结论可能成为决策的重要依据,它关系到一个企业的经济利益和一个产品的生死存亡.因此,必须对测量的结果给出可信程度的分析,测量不确定度就是对测量结果误差的定量评定.     

Uncertainty and Worst-Case Analysis in Electrical Measurements Using Polynomial Chaos Theory

In this paper, the authors propose an analytical method for estimating the possible worst-case measurement due to the propagation of uncertainty. This analytical method uses polynomial chaos theory (PCT) to formally include the effects of uncertainty as it propagates through an indirect measurement. The main assumption is that an analytical model of the measurement process is available. To demonstrate the use of PCT to assess a worst-case measurement, the authors present two examples. The first one involves the use of PCT to estimate the possible worst case of a measurement due to the propagation of parametric uncertainty of a low-pass filter. This case study concerns the analysis of nonlinear effects on the propagation of uncertainty of a signal-conditioning stage used in power measurement. In this paper, the PCT method is applied to determine the probability density function (pdf) of magnitude and phase of the frequency response of the filter and their impact on the power measurement. Of particular interest is the use of PCT to determine the worst-case, expected-case, and best-case effects of the filter, avoiding the reconstruction of the complete pdf of the filter output. The results illustrate the potential of this method to determine the significant boundary of measurement uncertainty, even when the uncertainty propagates through a nonlinear nonpolynomial function. In the second example, the authors use PCT to perform a worst-case analysis for an indirect measurement of a loop impedance. For both examples, the PCT method is compared with the numerical Monte Carlo analysis and the analytical method described in the guide on uncertainty on measurements (GUM).      

Uncertainty in NIST Force Measurements

This paper focuses upon the uncertainty of force calibration measurements at the National Institute of Standards and Technology (NIST). The uncertainty of the realization of force for the national deadweight force standards at NIST is discussed, as well as the uncertainties associated with NIST’s voltage-ratio measuring instruments and with the characteristics of transducers being calibrated. The combined uncertainty is related to the uncertainty of dissemination for force transfer standards sent to NIST for calibration.     

LED光谱辐射强度测量不确定度分析

与LED测量紧密相关的测量不确定度具有非常重要的意义。通过选择恰当的数量、装置等,可以举例分析不确定度计算的过程。试验中采用可溯源至NIM的光谱光度计和标准LED,通过实验和计算分析了LED光谱辐射强度的测量不确定度。     

校准恒温箱温度偏差和测量结果的不确定度分析

本文对恒温箱中心点真实温度校准,确定恒温箱温度显示偏差,对测量结果不确定度评定的分析。     

压力控制器测量值的不确定度评定

本文介绍了用0.05级压力标准器检定压力控制器中设定点偏差的测量不确定度分析方法,为压力控制器的检定提供可靠的依据。     

表面粗糙度比较样块测量的不确定度分析计算

分析了表面粗糙度比较样块Ra测量结果的不确定度来源并作了举例进行分析计算。     

Uncertainty Calculation for Spectral-Responsivity Measurements

This paper discusses a procedure for measuring the absolute spectral responsivity of optical-fiber power meters and computation of the calibration uncertainty. The procedure reconciles measurement results associated with a monochromator-based measurement system with those obtained with laser sources coupled with optical fiber. Relative expanded uncertainties based on the methods from the Guide to the Expression of Uncertainty in Measurement and from Supplement 1 to the “Guide to the Expression of Uncertainty in Measurement”-Propagation of Distributions using a Monte Carlo Method are derived and compared.An example is used to illustrate the procedures and calculation of uncertainties.