Zdenko Godec, Mladen Banović, Vilko Cindrić
AUTOMATED ESTIMATION OF MEASUREMENT UNCERTAINTY

Only complete expression of measurement result make possible correct and reliable decision making. Complete measurement result is the range of values determined with measured value, measurement uncertainty and measurement unit. Estimation of measurement uncertainty can be complex and time consuming for some digital instruments alone, and especially for results of indirect measurements. Using software it is possible to integrate digital instruments (with communication interface) and PC in an automated measuring system. Present automated measuring systems have features of automated measurements, storage of data, and report generation. To adopt these systems for a new demand of complete measurement result presentation, the additional steps are necessary: design of measurement model, measurement uncertainty analysis, design of algorithm for uncertainty estimation, and finally, automation of uncertainty calculation and presentation of complete measurement result. The process of complete measurement automation is illustrated on testing of power losses of power transformers with power analyzer (PA).

Domenico Grimaldi
AN IMPROVED PROCEDURE FOR QoS MEASUREMENT IN TELECOMMUNICATION SYSTEMS

The paper deals with (i) the characteristics of an improved signal-processing procedure for both voiced-unvoiced classification and echo parameter evaluation, and (ii) the reference signal selection to be adopted for clarity measurement. Improvements, respect to the traditional procedures, are achieved (i) in classifying the voice by means of the Learning Vector Quantization neural network, (ii) in echo parameter measurement by means of the recursive evaluation of the FIR filter coefficients estimating the impulse response of the echo path, and (iii) in the clarity measurement by using the optimized multi-sine signal. Numerical tests by using different types of telecommunication network noise show the efficacy of the proposed approach. The test results are also compared with the results obtained by different techniques presented in literature.

Rudi Čop, Mladen Maletić, Siniša Fajt
ULTRASONIC MEASURING CHAMBER FOR EXPERIMENTAL SYSTEM USING HF ULTRASONIC SHEAR WAVES

While developing a measuring chamber for the ultrasonic determination of the kinetics of hydration my interest concentrated on its quality of measurement. This reqoired the testing of its stability of temperature and humidity longitudinally. The testing was conducted using the HP VEE graphical programing language for standard instrumental control. The graphical programing language used is based on PC hardware and the Windows programing environment which decreased the development time by an impressive 60 percent. The development program offers traceable data connected to the ultrasonic measuring chamber, which can then be quickly accessed for further use.

Leopoldo Angrisani, Raffaele Colella
A DIGITAL SIGNAL PROCESSING METHOD FOR THE DETECTION AND EVALUATION OF I/Q IMPAIRMENTS IN RF DIGITAL TRANSMITTERS

Troubleshooting of radiofrequency (RF) digital transmitters is here dealt with. Specifically, a new digital signal-processing method is developed, which is capable of both detecting and evaluating the most recurrent impairments in the I and Q paths of the transmitter. Only the acquisition either of intermediate frequency (IF) or RF output signal is needed, thus avoiding any difficulty connected with the inaccessibility of baseband and/or IF section in a fully assembled transmitter. Moreover, the method has the required features of automation and effectiveness, granted by the use of RLS-based algorithms and proved by the results obtained in many experiments on actual IF and RF output signals. Even though the experiments presented in the paper refer to W-CDMA (Wideband Code Division Multiple Access) technology, the method shows itself suitable to troubleshoot any digital transmitter implementing quadrature amplitudemodulation (QAM).

Robert Frankowski, Sławomir Grzelak, Marcin Kowalski, Dariusz Chaberski, Marek Zieliński
TIME-INTERVAL MEASUREMENTS, USING TAPPED DELAY LINES IMPLEMENTED IN PROGRAMMABLE LOGICAL STRUCTURES

The time-interval measuring systems for timeresolved spectroscopy are discussed in this paper. For instance, for time-of-flight (TOF) spectrometry or lifetime decays measurement applications a simple gated counting system (boxcar), a real-time multichannel scaler (RTMS) or a time-interval interpolator is used. We present the new highresolution (RTMS) system for an intensity function measurement. In this system, the digital tapped delay lines are used. These system with 1,0 ns and 0,5 ns resolution, with tapped delay lines implemented in the structure of the complex programmable logic device FLEX10K 30E are presented.