9762 papers found
The resolution analysis of modern methods for frequency (period) measurements such as the ratiometric counting method and the method of the dependent count (MDC) is described in the paper. Comparative metrological performances for the methods and modeling results of resolution for the MDC with the help of Maple 6 software are given.
A set of resistance standards ranging from 100 Ω to 10 000 Ω and applicable to calibrations of wideband LCR meters has been prepared using surface mount metal foil resistors. Frequency dependences of these standards have been evaluated by comparing them with resistors having calculable frequency performance.
Poor repeatability and low accuracy often affect power measurements in digital wireless communication systems. A new digital signal processing-based method is proposed, which exploits Marple’s solution to parametric spectral estimation in order to achieve the power spectral density (PSD) of the analyzed signal, and then evaluates the quantities of interest by applying straightforward measurement algorithms to the estimated PSD. The performance of the method is assessed through a number of experiments on laboratory signals, and compared to that offered both by an alternative measurement...
Estimation of the output expectation and standard uncertainty in indirect measurements based on digital signal-processing (DSP) algorithms is dealt with. DSP measurement algorithms can, in fact, be considered as complex models, which operate on sampled data acting as direct measurement results. The related uncertainty sources can mainly be associated with the analog conditioning and analog-to-digital conversion the input signal undergoes. Due to the inherent non-analytical formulation of DSP measurement algorithms, the use of IEC-ISO recommendation for standard uncertainty estimation is...
The main objective of this Program of Interlaboratorial Comparison is to evaluate the results obtained in the unit of Wh, of the participants in relation to a reference, in our case, the Inmetro, as to: - used procedures of measurement; - metrology tracking of the standards; - compatibility of the standards due to uncertainty levels; - compatibility among the laboratories through the En pointer.
Usually correlation analysis (CA) is realized in Pulse Code Modulation (PCM) format that needs numerous mathematical operations with the large word length that limits the fast-acting of processing as well as the use of its to the measurement of wide-band noisy signals in real time. In this paper the use of signal representation in Sign Delta Modulation (SignDM) format has been proposed in order to increase the efficiency of the real time CA of short hardly noised signals. The SignDM codes are specified by comparing the values of differences between signal samples in PCM format with a...
A growing number of measurements in commercial and industrial sector needs to refer to the traceability to the national (and also international) standards. Since the internet-enabled metrology is rapidly developing in the recent years, it offers new possibilities for calibration services. This paper focuses on the problem of the visualization of the internet-enabled calibration process and instruments. The main goal is to identify the solution for real-time data monitoring and control of measurement equipment.
Weight filtration is performed in time domain through multiplying values of appropriate samples by a weighting function and summing the yielded products along the entire window length. The number of weight windows is unlimited. In his paper author is trying to define the filtration quality and its influence to the weight window selection.
Enforcement of Directive 40/2004/EC binds the EU member countries to define their legislative proceedings on the minimum health and safety requirements regarding the exposure of workers to the risk arising from physical agents (electromagnetic fields). In this paper guidelines for the determination and evaluation of low-frequency electromagnetic fields of high-voltage power stations are proposed. They are based on experiences gained with numerical calculations and measurements and are compatible with measurement practices and demands of international labot conventions and EU Directives.
The estimating methods of the meteorological parameters at Meteorology and Hydrology National Agency (ANMH) standard offers sufficient data to answered at the requirements of the population. Thus, it was ascertained that through the determination of fractal dimension of temporal series obtains different values for neighboring zones, values which should complete the already existing information and which should offer supplementary data concerning the efficiency of such stations.