A New Precision Digital Phase Meter and Its Simple Calibration Method

A digital phase meter (DPM) for power frequencies with a very low measurement uncertainty of 1 $muhbox{rad}$ was developed at Japan Electric Meters Inspection Corporation (JEMIC) to establish a power and energy calibration system. We also developed a phase meter calibrator (PMC) for calibrating the DPM. Since the DPM and PMC are synchronized with a single clock, the DPM can be calibrated by a very simple measurement method, which no longer requires extra standards. The DPM has been employed as an instrument for the primary standard of power and energy in Japan to achieve precise phase angle measurement. Since the error in the power measurement at power factor 0 is equal to the error in the phase angle measurement, we verified the performance of the DPM by calibrating a standard power meter using the power calibrators at JEMIC and Physikalische-Technische Bundesanstalt (PTB), and comparing the test results at power factor 0. According to the measurement, the phase angle difference between JEMIC and PTB is within 7 $mu hbox{rad}$.      

Pre-Calibration of the Phase Interpolator of a Precision Time Interval Meter

Measurement Techniques - The issues of precision determinations of time intervals for which results are essential, such as to estimate the metrological characteristics of structural systems of...     

基于89C2051单片机的精密相位表设计

文章介绍用 89C2 0 5 1单片机实现的数字相位表的硬件软件设计。应用双向过零平均鉴相原理 ,可消除器件的失调和温漂对测量的影响 ;用软硬件结合手法重构外中断口 ,给 5 1系列单片机提供了高电平与低电平(上升沿与下降沿 )都能触发外中断的方法 ;巧妙的软硬件对称设计 ,使绝大部分延时误差得以相互抵消     

A Precision Digital Phase Generator

The design of a digital phase generator which produces two outputs of frequency f, between which the phase shift can be varied from 0 to 360° in steps of 1°, from an input frequency of 360f, is described. The system design is described in detail. The circuit design and the choice of the circuit elements are discussed. Fast logic elements have been used in the construction of the instrument. A brief analysis of the performance of the system is also given. From the experimental results, which agree with the calculated performance, it is found that the accuracy of the system varies and is as high as 0.05 percent when the phase shift is 359°. The accuracy of the system is limited only by the propagation delays of the logic elements used and therefore can be improved by using faster logic elements.     

Linear Integrated Circuit Phase Meter

A precision phase meter with integrated circuits is described. Important features include variable sensitivity and automatic return toward midscale when the output approaches prescribed limits. The phase meter accepts inputs with frequencies from 10 to 100 kHz and with an amplitude range from 30 mV to 3 volts rms. The operational temperature range is from 0 to 50°C. The overall phase accuracy within these conditions is about 0.5°.     

0.4级精密压力表检定的不确定度分析

介绍0.05级标准活塞式压力计检定0.4级精密压力表示值误差测量结果不确定度的评定方法.     

德国联邦物理技术研究院(PTB)气体微流量计量评介

在真空技术应用中 ,高精度气体微流量计用于连续膨胀法校准系统压力的产生、漏孔漏率的测量以及真空泵抽速的测定。PTB先后研制了三代气体微流量计 ,第一代为手动型 ,第二代为半自动型 ,第三代为全自动型。本文详细介绍了PTB研制的气体微流量计的性能和特点 ,并介绍了气体微流量计在真空漏孔的漏率测量方面的应用。另外 ,还介绍了PTB最近研制的大气压力下漏孔漏率测量系统的性能和特点     

A Precision Ultrasonic Phase Velocity Measurement Technique for Liquids

Present paper reports the design and developmental aspects of a new technique for ultrasonic phase velocity measurement in liquids, which is based on the studies carried out on frequency dependence of ultrasonic velocity in pure, binary and ternary liquids/mixtures. The design and developmental aspects of the experimental set up are reported along with optimisation of data acquisition software developed in LabVIEW. Finally, the developed technique is used to measure phase velocity in water (W), aqueous solution of mannitol (M), binary mixture of tertiary butyl alcohol (TBA) in water and a tertiary mixture of TBA + W + M. The results are reported within frequency bandwidth from 3 to 7 MHz. The main reason for selecting these liquids was to identify some of the liquids which can be used as reference liquids for metrological applications. Although, reporting the systematic studies to find out the reference liquid is beyond the scope of the present paper due to obvious reasons, and will be dealt separately, but the studies certainly demonstrate that the technique can successfully be used for phase velocity measurement as a function of frequency and temperature.     

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。     

压力表检定时温度对标准压力表选择的影响

在进行弹簧管式压力表检定时,当环境温度偏离精密压力表检定所允许的温度公差情况下,必须考虑温度对标准压力表精度的影响,正确选择标准压力表精度等级以避免其给检定带来隐患。     

A Heterodyne Low-Level Signal Phase Meter Operating over 1 MHz to 300 MHz

After giving a brief summary of the main devices allowing the measurement of phase shifts between two sine signals in the approximate range 1 Hz-1 GHz, we propose a new apparatus for measuring phase shift. The principle of this apparatus uses a heterodyne technique in association with a phase-locked loop which brings about frequency translation of the measured signals. The intermediate frequency which is obtained is small with respect to the frequencies studied conveying a high degree of selectivity to the apparatus. This allows measurements to be made on signal with noise or low-level signal while also maintaining good accuracy. For a system operating from 1-300 MHz, we have obtained phase linearity of ± 1°, resolution of 0.1°. In obtaining the accuracy of ± 5°, the sensitivity is -86 dBm in the 1-30-MHz frequency range; with 300 MHz the sensitivity reached is -68 dBm.     

直流电压下对高精度数字多用表的不确定度评定

高精度数字多用表是目前比较常用的数字仪表,其具有的分辨力高、精准度高、测试速度快、显示直观等优势,因此高精度数字多用表能够在电子测量领域得到广泛运用。文中,笔者以直流电压10V量程10V点为例来对高精度数字多用表进行了测量,并以测量结果来对高精度数字多用表进行不确定度的评定和分析。     

高精度工频相位计研制

本文从分析典型的相位差数字化测量方法入手,对实测精度优于0.02°的工频相位计的硬件及软件机理进行了介绍,并对提高相位差测量精度的技术措施及相关电路进行了详细说明。     

等精度频率计误差分析及改进型设计

介绍了等精度频率计的优缺点,并对其士1个计数误差进行分析,限制测频精度进一步提高,提出了通过相位同步法来消除士1个计数误差,并在FPGA芯片上验证,获得理想的仿真结果。     

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。     

高精度弯管流量计的理论研究和实验验证

通过求取N-S方程数值解的方法对弯管流量计进行理论研究,得出其测量准确度不仅与传感器自身的管径、曲率半径、弯径比、压力测点位置等几何结构尺寸的准确度有关,而且还与测量使用的条件有关。特别是弯管流量计与前后直管段产生的安装偏转角、直管段管径与其自身管径的一致性等环境应用条件会对弯管流量计的高精度使用产生影响。针对上述影响因素,通过对用整体数控加工的、自身带有直管段的弯管流量计进行反复实验, 结果表明:在2σ准则下,弯管流量计可以达到0.5%的测量准确度水平;不同管径情况下,流量系数也具有良好的一致性。     

Improved Reactive Power Measurement through Precision Phase Angle Determination

In the past, the accuracy of reactive measurement has been substantially limited by the precision with which two voltages in quadrature could be generated. A technique employing a commercially available electronic phasemeter has been developed whereby phase angles may be established very precisely. This technique is described in the context of reactive measurements, and other applications are suggested as well.     

电子式三相电能表示值误差的测量不确定度评定

本文用一个实例阐述了测量不确定度的评定方法和过程。测量不确定度比误差更有说明测量质量好坏的能力,测量不确定度比误差更全面更具体。