共查询到20条相似文献,搜索用时 15 毫秒
1.
Translated from Izmeritel'naya Tekhnika, No. 4, pp. 49–51, April, 1990. 相似文献
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A study of the uncertainties in calibration using capacitance diaphragm gauges as reference standard in the range from 1000 mbar to 10−3 mbar is presented. The contributions to the expanded uncertainty are: (i) Uncertainty from the calibration certify of the reference standard; (ii) Long-term stability or shift; (iii) Uncertainties inherent to the reference standard; (iv) Uncertainties derived from the calibration chamber; and (v) Uncertainties derived from the calibration procedure. These contributions have been determined for four reference standard capacitance diaphragm gauges of 1.3 mbar, 13 mbar, 130 mbar and 1300 mbar full scale used in routine calibration. Long-term stability or shift jointly with the uncertainty displayed in the calibration certifies issued by a National Metrological Laboratory are the main contributions to the expanded uncertainty. Values of the shift for each of the reference standard for a period of several years are presented and discussed. Best-expanded uncertainties obtained from calibration of a gauge of similar characteristics to the reference standards are:
10−3-1 mbar 4-0.2% of the reading 1-13 mbar 0.2% of the reading 13-130 mbar 0.2-0.08% of the reading 130-1300 mbar 0.2-0.06% of the reading - Full-size table
3.
Watt and voltampere transfer standard 总被引:2,自引:0,他引:2
Filipski P.S. Arseneau R. Zelle J.J. 《IEEE transactions on instrumentation and measurement》1993,42(2):170-175
A new instrument which will be used as a transfer device between the national watt and VA standards of the National Research Council of Canada and the standards maintained by Canadian electrical utilities and electricity meter manufacturers is described. The relative error of this instrument is less than 50 ppm for power or energy and 100 PPM for voltampere measurements. The stability of the instrument during a field test cycle of about two weeks was on the order of 20 ppm. A dedicated pulse-frequency counter and a stable phantom power source were supplied to utilities to achieve high-accuracy on-site measurements 相似文献
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Huang S. Green R.G. Plaskowski A. Beck M.S. 《IEEE transactions on instrumentation and measurement》1988,37(3):368-373
A stray-immune capacitance measuring instrument based on the charge transfer principle is described. It has a programmable measurement frequency up to several megahertz and is inexpensive and suitable for integration onto a single chip. The effects of stray capacitances, including those of the switching components, have been eliminated by using a special switching arrangement, resulting in a baseline drift of 0.02 pF (at 1-MHz measurement frequency) over a 12-h period 相似文献
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Filipski P.S. Rinfret R.L. 《IEEE transactions on instrumentation and measurement》1998,47(5):1067-1071
The paper describes improvements in the determination of the ac-dc transfer difference of an electronic low-voltage transfer standard (LVTS). Expanded calibration uncertainty in the 10 Hz-1 MHz frequency range and 2 mV-100 mV voltage range has been estimated to be less than 100 μV/V. Improvements have been achieved by modification of the step-down procedure that does not require loading error corrections and careful examination of the error sources 相似文献
8.
Tests on the electrometric AC-DC transfer standard built at IEN have been performed. The instrument was shown to work correctly, and comparison with thermal converters showed a short-term repeatability (1σ) of about 2 parts in 106. Mechanical effects such as deformations and vibrations have been analyzed, both theoretically and experimentally. Direct determinations of the transfer difference made using thermal converters have shown results almost comparable with those obtained by the step-up procedure. The long-term stability of the instrument has also been investigated 相似文献
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A thermal converter to DC voltage, with 10-ppm accuracy and a frequency range of 0-200 kHz, which can be used for active power measurements, has been developed using an infrared thermal converter. Moreover, a proposal for implementing, with lower accuracy, the converter for energy and reactive power is also illustrated 相似文献
11.
Haasz V. Roztocil J. Slepicka D. 《IEEE transactions on instrumentation and measurement》2005,54(3):1150-1155
A transportable high-stability reference AD device was designed and built to compare the systems for testing the dynamic quality of analog-to-digital converters (ADCs) or analog-to-digital (AD) modules. Three different input modules can be used in the frequency range up to 5 MHz. First, this paper refers to the results of an AD device application in the frequency range of the testing signal up to 100 kHz, where four ADC testing systems were compared in different laboratories, and a short time amplitude and/or frequency instability of testing signal generators was evaluated. Second, it describes the first experience of its application in the frequency range from 100-5 MHz. 相似文献
12.
Boella G. Capra P.P. Cassiago C. Cerri R. Reedtz G.M. Sosso A. 《IEEE transactions on instrumentation and measurement》2001,50(2):245-248
The traditional scaling method used at the Istituto Elettrotecnico Nazionale (IEN) for the calibration of the 10-kΩ standard is compared with more straightforward techniques: one based on the linearity of a DVM and the other on a commercial current comparator bridge. For the three methods, the measurement results and the uncertainty budgets are reported. The agreement is better than 1×10-7 相似文献
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Source-based radiometry requires reliable transfer standards which are easy to handle. For low irradiances in the UV spectral
range, 30 W deuterium lamps are commonly used. However, for the growing field of high UV irradiance applications, new high
power standards are required. Here we report on a Xe-Hg lamp system which has been characterised and improved to match the
high requirements of a working standard. For this purpose, several parameters of the system such as lamp stability, re-ignition
reproducibility, irradiance uniformity and usability have been investigated. Components for the customised light guide-based
output optics have been selected with the help of extensive characterisations. The resulting lamp system can be used for a
high-grade instrument calibration at high UV irradiance levels. 相似文献
15.
This paper describes the results of the interlaboratory comparison for pressure measurements of 9 laboratories that are accredited
by the National Accreditation Board for Testing and Calibration of Laboratories (NABL). The artifact used for the comparison
was a pressure balance covering the pressure range (7 to 70) MPa. The primary objective of this comparison was to assess the
laboratory’s technical competence to perform measurements and also to assess the compatibility of the results submitted by
the laboratories. The comparison began during March 2008 and ended during April 2010. For assigning the reference values,
the pilot laboratory (NPLI) carried out 3 calibrations of the transfer standard; the first one at the beginning, the second
at the middle and the last one at the end of the programme. The comparison was carried out at 10 pressure points i.e. (7,
10, 15, 20, 25, 30, 40, 50, 60 and 70) MPa throughout the entire pressure range of (7 to 70) MPa. The measurements were carried
out by each laboratory with their own resources (personnel, calibration systems, environmental conditions in their installations).
The deviations for each laboratory were compared against the reference values and the compatibility of the results was calculated
using the normalized error value method. Out of the total 87 measurement results reported, 68 (78.2%) results are found in
good agreement with the results of the reference laboratory. The normalized error (En) values of 5 laboratories out of the total 9 were found well within ± 1 over the entire pressure range. However, 2 other
laboratories had shown good agreement with the reference values except one pressure point each. The En values of one of the participating laboratory were found beyond acceptable limits at all measurements points. Another laboratory
had acceptable results only at 3 pressure points. The laboratories with unacceptable results have been advised to review their
pressure measurement process. The deviations between laboratory values and of the reference values were found well within
the uncertainty band of the reference values for 37% measurement results. The relative deviations for 82 measurement results
were found well within 0.05%. 相似文献
16.
电容传感器新型电容测量电路设计 总被引:9,自引:0,他引:9
提出了一种基于V/T变换的用于电容传感器的电容测量电路。它将被测微小电容变化量转换成时间信号并由单片机进行处理,电路结构简单,电路中没有影响测量稳定性和产生零点漂移的元器件,大幅度地降低了测量过程中的噪声。 相似文献
17.
Two different dilatometric devices designed for magneto-strictive strain measurements at low temperatures are described. Their sensitivity is of the order of 10?10 for relative length changes. They are provided with an adjustable gap system which makes it possible to change the gap between the capacitor plates at helium temperature. 相似文献
18.
Suzuki Y. Chida N. Komiyama M. 《IEEE transactions on instrumentation and measurement》1992,41(1):45-49
A calorimeter which can measure microwatt-level optical power has been developed for an optical power transfer standard. It can measure the optical power of a light beam and can be used with optical fiber simply by attaching an adapter. This calorimeter sensor uses a compensative absorber to reduce the influence of pressure fluctuation and temperature variation in the measurement room and an ultra-low-noise preamplifier. With this calorimeter, the standard deviation of the measured value is in the range of 0.02-0.4% in 20-mW to 10-μW optical power measurements. An error evaluation for an optical power level of 10 μW yielded a two-sigma (two standard deviation) total uncertainty of 0.9% 相似文献
19.
Progress toward an understanding of the frequency dependence of capacitance and resistance standards at frequencies up to 10 MHz is presented. A qualitative comparison is also made for capacitance and dissipation factor measurements between the National Physical Laboratory (NPL) high-frequency four terminal-pair (4TP) bridge and a commercial impedance analyzer for the first time. A set of novel high-frequency calculable coaxial resistance standards, of nominal 100 /spl Omega/ and 1 k/spl Omega/ values, have been developed and their calculated frequency dependence up to 1 MHz is given. 相似文献