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algorithm for measurement and processing of results from total harmonic distortion calibration of power quality analyzers by using standard periodic non-harmonic signals 31

Algorithm for measurement and processing of results from tot...

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31st International Scientific Symposium on Metrology and Metrology Assurance (MMA)

作者： Tzvetkov, Plamen Marinov Galabov, Krasimir Simeonov Kodjabashev, Ivan Nikolov New Bulgarian Univ Dept Telecommun Sofia Bulgaria Tech Univ Sofia Dept Elect Measurements Sofia Bulgaria

ISBN: (纸本)9781665445375

The approach to calibrate the coefficient of total harmonic distortion of power quality analyzers using reference standard non-harmonic waveform signals, instead of the traditionally used set of harmonic signals is considered in [1]. Using a reference calibrator, square, triangular, saw-shaped signals and a truncated sine wave signal are generated in series, which provide setting of appropriate reference values of the total harmonic distortions for which the analyzer is calibrated. In the present work, a computer-based automation system and algorithm for calibration of Power Quality Analyzer are proposed by THD. The algorithm performs the sequence of operations for control of the reference calibrator and the calibrated analyzer, setting reference values of THD of the voltage/current from the calibrator, performing multiple measurements at the calibration point, measured results are extracted from the analyzer and their processing and an estimate of the actual value of the measured THD values and an estimate of the extended uncertainty is obtained at the analyzer calibration point.

关键词： Power Quality Analyzers Total Harmonics Distortion of Voltage and Current calibration algorithm

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True RMS voltmeter calibration by reference square waveform signal and algorithm for measurement and processing of results 31

True RMS voltmeter calibration by reference square waveform ...

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31st International Scientific Symposium on Metrology and Metrology Assurance (MMA)

作者： Tzvetkov, Plamen Marinov Galabov, Krasimir Simeonov New Bulgarian Univ Dept Telecommun Sofia Bulgaria Tech Univ Sofia Dept Elect Measurements Sofia Bulgaria

ISBN: (纸本)9781665445375

An approach for calibrating of the AC voltage of True RMS voltmeters is proposed, using reference square waveform signals instead of the traditionally used harmonic (sinusoidal) signal. A computer-based automation system and an algorithm for calibration of True RMS voltmeters have been implemented. The algorithm performs the sequence of operations for control of the reference calibrator Metrix CX1651 and the calibrated True RMS voltmeter PICOTEST M3500A, setting reference voltage values from the calibrator, performing multiple measurements at the calibration point, extracting measured results and extracting the measured results to obtain an estimate of the actual value of the measured voltage values and an estimate of the extended uncertainty at the calibration point. Based on the results of calibrations, the two approaches were analyzed and compared, which proved their equivalence.

关键词： calibration True RMS voltmeter square waveform signal calibration algorithm

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True RMS Ammeter calibration by Using Standard Square Waveform Signal and algorithm for Measurement and Processing of Results 32

True RMS Ammeter Calibration by Using Standard Square Wavefo...

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XXXII International Scientific Symposium Metrology and Metrology Assurance (MMA)

作者： Tzvetkov, Plamen Marinov Galabov, Krasimir Simeonov New Bulgarian Univ Dept Telecommun Sofia Bulgaria Tech Univ Sofia Dept Elect Measurements Sofia Bulgaria

ISBN: (数字)9781665485692

ISBN: (纸本)9781665485692

A computer-based system and algorithm for calibration of True RMS ammeters is proposed. An approach was used to calibrate True RMS ammeters by using standard square waveform signals as an alternative of the classical used harmonic signal. Based on a developed algorithm, the calibration system performs the sequence of steps for controlling the Metrix CX1651 standard calibrator and the calibrated True RMS ammeter PICOTEST M3500A. For this purpose, standard True RMS current values from the calibrator are set, multiple measurements are made at the calibration point, measured results from the ammeter are derived and processed to receive an estimate of the actual value of the measured current values and an estimate of the expanded uncertainty at the calibration point. Results of calibrations using classic sinusoidal and square waveform signals were received, and the two approaches were compared and analyzed, which evidenced their equivalence.

关键词： square waveform signal calibration calibration algorithm True RMS ammeter

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An Improved Longitude-Latitude Mapping algorithm for Fisheye Image calibration

An Improved Longitude-Latitude Mapping Algorithm for Fisheye...

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Annual Conference of the Chinese-Society-for-Optical-Engineering (CSOE) on Applied Optics and Photonics China (AOPC) - Optical Sensing and Imaging Technology and Applications

作者： Zhao, Yan Xie, Hongxing Yao, Jianmin Chen, Enguo Xu, Sheng Fuzhou Univ Natl & Local United Engineer Lab Flat Panel Displ 2 Xueyuan Rd Fuzhou 350116 Fujian Peoples R China

ISBN: (数字)9781510614062

ISBN: (纸本)9781510614062;9781510614055

Field of view (FOV) of the fisheye lens is close to or even higher than 180 degrees, which brings about extraordinary imaging effect that the visual range would be far wider than the human eye perspective. However, the wide visual range of the fisheye lens is always at the expense of image quantity, so that the images obtained by fisheye lens would inevitably show a large degree of distortion aberration. In this paper, we propose an improved distortion calibration algorithm of longitude-latitude mapping to eliminate the image distortion aberration caused by fisheye lens. This method does not need to depend on a specific physical camera and has general and universal significance. By using Matlab as a mathematical analysis tool, the verified experiment and the corresponding write code is performed to correct a specific fisheye lens' image based on the previously proposed algorithm. A reverse mapping is used to avoid cross-border problems, and comparative experiments are also analyzed to show the difference between the image processing with the traditional and the proposed algorithm. Experimental results demonstrate that the proposed algorithm can better achieve the correction of fisheye lens distortion. The twisted lines that are not expected can be well corrected into the straight lines. This method can not only reduce the problem of horizontal stretching of the image, but also make the processing results visually consistent with people's viewing habits.

关键词： Fisheye image distortion calibration algorithm longitude-latitude mapping horizontal stretching

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Comparison of the calibration algorithms and SI Traceability of MODIS, VIIRS, GOES, and GOES-R ABI Sensors

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REMOTE SENSING 2016年第2期8卷 126-126页

作者： Datla, Raju Shao, Xi Cao, Changyong Wu, Xiangqian ERT Inc NOAA Affiliate Laurel MD 20707 USA Univ Maryland Dept Astron College Pk MD 20742 USA NOAA NESDIS STAR College Pk MD 20737 USA

The radiometric calibration equations for the thermal emissive bands (TEB) and the reflective solar bands (RSB) measurements of the earth scenes by the polar satellite sensors, (Terra and Aqua) MODIS and Suomi NPP (VIIRS), and geostationary sensors, GOES Imager and the GOES-R Advanced Baseline Imager (ABI) are analyzed towards calibration algorithm harmonization on the basis of SI traceability which is one of the goals of the NOAA National calibration Center (NCC). One of the overarching goals of NCC is to provide knowledge base on the NOAA operational satellite sensors and recommend best practices for achieving SI traceability for the radiance measurements on-orbit. As such, the calibration methodologies of these satellite optical sensors are reviewed in light of the recommended practice for radiometric calibration at the National Institute of Standards and Technology (NIST). The equivalence of some of the spectral bands in these sensors for their end products is presented. The operational and calibration features of the sensors for on-orbit observation of radiance are also compared in tabular form. This review is also to serve as a quick cross reference to researchers and analysts on how the observed signals from these sensors in space are converted to radiances.

关键词： remote sensing calibration algorithm calibration equations SI traceability LEO and GEO optical sensors

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Effects of input data accuracy, catchment threshold areas and calibration algorithms on model uncertainty reduction

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EUROPEAN JOURNAL OF SOIL SCIENCE 2024年第4期75卷 e13519-e13519页

作者： Wu, Lei Xu, Yonghong Li, Ruizhi Northwest A&F Univ Key Lab Agr Soil & Water Engn Arid & Semiarid Area Minist Educ Yangling 712100 Shaanxi Peoples R China Northwest A&F Univ State Key Lab Soil Eros & Dryland Farming Loess Pl Yangling Shaanxi Peoples R China Northwest A&F Univ Coll Water Resources & Architectural Engn Yangling Shaanxi Peoples R China Minist Water Resources Xifeng Hydrol & Water Resources Survey Bur Yellow Qingyang Gansu Peoples R China

Low resolution of input data and equifinality in model calibration can lead to inaccuracy and insufficient reflection of spatial differences, thereby increasing model errors. However, the impact of input data accuracy, catchment threshold area, and calibration algorithm on model uncertainty reduction has not yet been well understood. The sequential uncertainty fitting version 2 (SUFI-2) that is linked with the Soil and Water Assessment Tool (SWAT) in the package called SWAT calibration Uncertainty Programs (SWAT-CUP) was introduced to quantify the effects of different input data resolutions on parameter sensitivity and model uncertainty in the Jinghe River watershed, and the effects of different sub-basin delineations and other two calibration algorithms on model uncertainty were also comparatively analysed. (i) USLE_C, EPCO, ALPHA_BNK, and CN2 are the most sensitive parameters among all SWAT projects. When the change of digital elevation model (DEM) resolution is small, the sensitivity of parameters does not change obviously. When the DEM resolution changes significantly, BIOMIX, LAT_SED, USLE_K, and CH_N1 become highly sensitive parameters by replacing OV_N, SMTMP, SURLAG, and USLE_P. However, the change in land use resolution has little impact on parameter sensitivity, with only a slight change in the sensitivity ranking of specific parameters. (ii) Model uncertainty responded to changes in the resolution of DEM more than land use. Most of the runoff simulations had smaller uncertainties (P factor, R factor, percentage of bias [PBIAS]) than sediment. High resolution DEM data reduced model uncertainty, but the models with 2000 m DEM resolution also achieved small uncertainty. Small catchment threshold area leads to high uncertainty of the model, and large catchment threshold areas decrease the model uncertainty. The model has relatively good simulation effects in runoff and sediment when the catchment threshold area was 2000 km(2). (iii) The SWAT model has differe

关键词： calibration algorithm catchment threshold area DEM data land use data model uncertainty

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A new calibration method for ductile fracture models as chip separation criteria in machining

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SIMULATION MODELLING PRACTICE AND THEORY 2010年第9期18卷 1286-1296页

作者： Vaziri, M. R. Salimi, M. Mashayekhi, M. Isfahan Univ Technol Dept Mech Engn Esfahan Iran

Several leading commercial FEM codes offer a number of fracture options without giving any guidance to the users in determining the fracture parameters for different materials. A modification is implemented to Johnson and Cook's calibration method to provide simultaneous consideration of both active failure mechanisms in actual domain of the field variables. Application of FE simulation of machining to accumulate damage is the key point to solve problems of available calibration method. As a result, a new set of fracture constants is presented for AISI 1045 steel. It is demonstrated that due to different failure mechanism a unique fracture model cannot be the representative of crack generation in all machining zone. Then the classical Lagrangian simulation is modified based on this concept. (C) 2010 Elsevier B.V. All rights reserved.

关键词： Chip separation criterion Cumulative damage model calibration algorithm

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A 70.7-dB SNDR 100-kS/s 14-b SAR ADC with attenuation capacitance calibration in 0.35-μm CMOS

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ANALOG INTEGRATED CIRCUITS AND SIGNAL PROCESSING 2016年第2期89卷 357-371页

作者： Brenna, Stefano Bonfanti, Andrea Lacaita, Andrea Leonardo Politecn Milan Dipartimento Elettron Informaz & Bioingn Via Golgi 40 I-20133 Milan Italy Intel Labs 2111 NE 25th Ave Hillsboro OR 97124 USA

In sensor applications, low-power and moderate-high resolution analog-to-digital converters (ADCs) are needed to convert the analog front-end signal output. Such systems are often multi-channel and require analog multiplexing. In these cases, even when high resolutions are required, continuous time Delta Sigma ADCs can't be adopted, and an efficient data-conversion must be achieved relying on different topologies, typically successive approximation-register (SAR) ADCs. Since these systems are often implemented in CMOS processes like 250- and 350-nm CMOS to benefit from a large supply voltage, the SAR ADC design is challenging due to the technology mismatch and to the limited number of metals available to optimize the layout. This paper presents a SAR ADC implemented in 350-nm CMOS technology with a physical resolution of 14 bits using a binary weighted with attenuation capacitor array. The proposed converter exploits a semi-custom and isotropic unit capacitance with ground shield to avoid proximity effects and parasitic capacitances across its terminals, an optimized capacitive array layout insensitive to both linear and radial oxide gradients, and an efficient calibration algorithm to compensate the parasitic capacitances that worsen the converter linearity. At 1.8-V supply and 100-kSps sampling frequency, the proposed ADC achieves an SNDR of 70.7 dB, an SFDR of 81.8 dB, an ENoB of 11.45 and a power consumption of 43.4 mu W, corresponding to a figure-of-merit (FoM) of 155 fJ/conv.-step. To the best of our knowledge, this figure is the best among SAR converters implemented in 350-nm or less scaled technologies, and in-line with other ADCs featuring an SNDR larger than 70 dB.

关键词： ADC Analog-to-digital conversion Nonlinearity Mismatch Asynchronous logic Successive approximation register calibration algorithm

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Design and calibration of Wideband Multiport Homodyne Wireless Receivers

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IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT 2017年第12期66卷 3160-3169页

作者： Zhang, Weiwei Hasan, Abul Ghannouchi, Fadhel M. Helaoui, Mohamed Wu, Yongle Liu, Yuanan Beijing Univ Posts & Telecommun Sch Elect Engn Beijing Key Lab Work Safety Intelligent Monitorin Beijing 100876 Peoples R China Univ Calgary Intelligent RF Radio Lab Dept Elect & Comp Engn Schulich Sch Engn Calgary AB T2N 1N4 Canada

Complexity and computation effective design of multiport-based receiver system is proposed in this paper, and a simple calibration algorithm based on modified memory polynomial for the five-port receiver is used to demodulate the desired baseband signals from the received radio frequency signals. The theoretical foundation for the baseband signal recovery for the multiport system, basic circuit theory of the five-port receiver, and the proposed algorithm about how to retrieve the baseband signals from three output voltage signals are discussed. Finally, common modulated signals are used in the five-port receiver to validate the proposed calibration algorithm, and the measured performance in terms of error vector magnitude between the transmitted and the received signals are all less than 2%. Also, the performance comparison with the state-of-the-art multiport receivers is made to conclude that the five-port receiver with the proposed model can be one of the best cost and computation effective choices to accurately complete the signal recovery.

关键词： calibration algorithm error vector magnitude (EVM) five-port receiver modified memory polynomial (MMP) modulated signals

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High-Precision calibration Scheme for RIMU

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IEEE ACCESS 2019年 7卷 72376-72386页

作者： Cheng, Jianhua Liu, Ping Gao, Peng Zou, Mingfeng Fu, Wenhuan Harbin Engn Univ Coll Automat Harbin 150001 Heilongjiang Peoples R China

Due to the diversity of redundant configuration schemes, the existing calibration algorithm for the redundant inertial measurement unit (RIMU) cannot be applied generally. In addition, the linearized calibration model utilized in the traditional calibration algorithms also leads to low calibration accuracy. In this paper, a high-precision calibration scheme is proposed for the RIMU, which can be applied generally. At first, a general calibration model for the RIMU is established. Then, a zero-space amplification algorithm is applied to improve the observability of the system. At last, the extended Kalman filter (EKF) based on the second-order Taylor series expansion is proposed, which can estimate the biases, scale factor errors, and installation errors simultaneously. The simulation and experimental results demonstrate that the proposed calibration algorithm calibrates the system accurately and improves the performance of the RIMU effectively. Furthermore, the proposed algorithm can be applied generally in all kinds of RIMU.

关键词： calibration algorithm extended Kalman filter (EKF) calibration model redundant inertial measurement unit (RIMU) Taylor series expansion

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