Jaroslav Bohacek
REFERENCE RESISTORS FOR CALIBRATION OF WIDEBAND LCR METERS

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.

Leopoldo Angrisani, Aldo Baccigalupi, Massimo D’Apuzzo, Rosario Schiano Lo Moriello
ON THE USE OF THE UNSCENTED TRANSFORM FOR UNCERTAINTY EVALUATION IN DSP-BASED MEASUREMENTS

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 usually unfeasible. The paper aims at showing the efficacy and reliability of an original approach, mandated to uncertainty estimation and based on the unscented transform, when applied to DSP measurement algorithms. A number of numerical tests are conducted on simulated measurement data. Remarkable concurrence between obtained estimates and those granted by Monte Carlo simulations confirms the efficacy of the proposed approach.

Wlodzimierz Pogribny, Igor Rozhankiwsky, Tadeusz Leszczynski
MEASUREMENT OF SHORT NOISY SIGNAL PARAMETERS WITH THE USE OF SIGN DM

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 differential zone which is defined a priori. These two bit codes reflect the signal character and are suitable for CA as well. In this paper there are presented the fast and exact algorithms of the SignDM CA, as well as the computer simulation results for resolution of CA of short noisy signals at the various differential zone and initial phases.

Artur Wollek
INFLUENCE CRITERIONS OF QUALITY TO THE WEIGHT WINDOWS SELECTION

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.

Laurentiu-Dan Milici, Mihai Cretu, Mariana-Rodica Milici
FRACTAL ANALISYS METHODS IN ESTIMATION AND PREDICTION OF SOME METEOROLOGICAL PARAMETERS

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.