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Measure Articles 2018 (4)

 
Picture of the productAchievable Accuracy in Industrial Measurement of Dissipation
Achievable Accuracy in Industrial Measurement of Dissipation Factor of Power Capacitors
Anders Bergman, MTz, Measurement Science and Technology, RISE Research Institutes of Sweden, Borås, Sweden
Modern dielectrics used in power capacitors can exhibit a dissipation factor lower than 0.005 %, which approaches the limits of presently available measurement techniques. This article reviews techniques, apparatus, and available calibration services for dissipation factor with regard to lowest achievable uncertainties. It is shown that further metrological advances are necessary to lower uncertainty in the measurement to levels at least five times less than presently achievable, in order to ensure traceable and quality-assured measurement of modern dielectrics with such low dissipation factors.


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MS18_01_BERG
Picture of the productAutomated Piston Gauge Calibration System
Julia Scherschligt, Christina D. Cross, John Quintavalle, Yuanchao Yang, R. Gregory Driver, Katie Schlatter, and Douglas A. Olson, National Institute of Standards and Technology, Gaithersburg, Maryland, USA
Piston gauges or pressure balances are important primary standards for the realization of the SI unit of pressure, the pascal. Because of their long-term stability, they are also used as secondary or working standards in the dissemination of the pressure scale. The National Institute of Standards and Technology (NIST) operates and maintains a calibration service for these devices, and has recently undertaken a modernization effort. Following a preliminary investigation into the feasibility of using transducers as instantaneous in-situ transfer standards, we now present the results of a near fully automated calibration system. This effort includes the design, building, and validation of an automated gas-handling manifold, and the development of a new software suite. The new system demonstrates an expanded uncertainty on the order of 1 in 105, comparable to the traditional system, but offers a five-fold decrease in calibration turnaround time.


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MS18_01_SCHERS
Picture of the productCalibration of Electrocardiograph (ECG) Simulators
Steven Yang, Brenda Lam, and Chris M. N. Ng, Standards and Calibration Laboratory, The Government of Hong Kong Special Administrative Region, Hong Kong, China
The Standards and Calibration Laboratory (SCL) in Hong Kong has set up a calibration facility for electrocardiograph (ECG) simulators. ECGs are medical devices designed to measure the electrical signals associated with cardiac activities. They are used to diagnose heart diseases and arrhythmias, and are commonly used in hospitals, emergency facilities, and medical institutes. Routine performance check of ECGs could be performed by ECG simulators. To ensure the accuracy of ECGs, traceable calibration to SI units is essential. At the SCL, the output signal from an ECG simulator is measured by a differential amplifier and a high-speed digital sampling system. The digital sampling system enables the calibration of non-sinusoidal signal with high accuracy. Signal characteristics including signal amplitude, frequency, and wave shape could be evaluated by an in-house developed program for normal sinus rhythm waveforms as well as for performance waveforms.


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MS18_01_YANG
Picture of the productCalibration of Optical Fiber Time Domain Reflectometers
Calibration of Optical Fiber Time Domain Reflectometers in Accordance with IEC 61746-1:2009
Samuel C. K. Ko and Terry Hau Wah Lai, Standards and Calibration Laboratory, The Government of Hong Kong Special Administrative Region, Hong Kong, China
This article describes the calibration system developed by the Standards and Calibration Laboratory (SCL) for calibrating single mode optical time domain reflectometers (OTDR) fitted with FC connectors at wavelengths of 1310 nm and 1550 nm in accordance with the international standard IEC 61746-1:2009. The parameters calibrated include distance deviation, attenuation deviation, and reflectance deviation. The principle of the calibration is to compare a set of reference standards, namely a distance calibration artifact, an attenuation calibration artifact, and reflectance calibration artifacts against the measured values by the OTDR under test. The expanded measurement uncertainties with 95 % level of confidence for the distance, attenuation, and reflectance deviation calibration are 2 m, 0.04 dB, and 1.7 dB, respectively.


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MS18_01_KO