Giovanni Betta, Domenico Capriglione, Gianni Cerro, Luigi Ferrigno, Gianfranco Miele
A NOVEL POLYNOMIAL FILTERING METHOD FOR DATA SMOOTHING IN COGNITIVE RADIO APPLICATIONS

The smoothing process is a fundamental task in many application fields. This paper proposes a novel method to smooth raw data, based on the concept of polynomial fitting. It is thought to be effective in Cognitive Radio applications, especially focused on spectrum sensing tasks. The method is intended to be used instead of today’s traditional smoothing filters, because of some advantages in terms of shaping retainment, data shifting problem avoidance, acceptable computational intensity, appreciable noise reduction property. The goodness of the proposal has been proved considering the H₁ norm operator as performance index.

Thiago Brito Pereira de Souza, Marcelo Melo da Costa, André Ferraioli Neto
IMPROVEMENTS IN THE ENERGY METERS CALIBRATION PROCESS IN ELETROBRAS ELETRONORTE

The measurement of electrical energy is very important for Eletrobras Eletronorte, as this is their main product offered to its customers. This paper aims to implement improvements in the calibration process of this electricity meters used in measuring systems. These improvements presented achieve greater reliability in the calibration process, greater availability of measurement standards in the laboratory and the reduction of meter calibration time. This paper presents strategies to improve the calibration process of these meters, with results that characterize the effectiveness of the proposed improvements provided benefits related to quality of service and reducing the cost of calibration of the meters.

Pavel F. Baranov, Edvard I. Tsimbalist, Valeriy N. Borikov, Diana G. Soltanova
MEASUREMENT OF THE CURRENT TRANSFER RATIO FOR CURRENT SHUNTS

Current shunts are widely used in metrological practice. The shunt is required to determine the value of its resistance on DC and AC currents to determine the transfer ratio error in the wide frequency band in process calibration. The paper describes a procedure for measuring the complex impedance of transfer ratio of current shunts in the frequency band using the lock-in amplifier with the differential input. The experimental results of the proposed procedure are described.

Pasquale Arpaia, Carlo Baccigalupi, Miguel Cerqueira Bastos, Michele Martino
DESIGN OF A 1 µs REAL-TIME LOW-NOISE DATA ACQUISITION FOR POWER CONVERTERS CONTROL LOOP

The proof of principle of a real-time data acquisition system to be integrated into a digital control loop for controlling the power converters of the Compact LInear Collider is presented. The system is based on an ultra low noise analogue front-end with 1.1 ppm RMS noise (referred to input), and about 1 µs of real-time delay. After the analogue conditioning, a fully-differential analogue-to-digital converter is foreseen. The requirements of this system, directly derived from the accelerator performance, are discussed and translated into design specification. The results obtained by means of Pspice simulations are reported in order to prove that the design is feasible with the proposed architecture. Finally, the results of the experimental validation of the prototype, currently under design, will be included in the final paper.

Dušan Agrež
FREQUENCY ESTIMATION IN THE MEASUREMENT TIME BELOW ONE PERIOD

In paper, a frequency domain estimation algorithm for fast measurement of the signal frequency in the measurement time below one period is presented. When the time is shortened below the signal period, the DC coefficient of the discrete Fourier transformation is taken into account. An analysis is made to study the influence of the leakage effect, offset in the measurement channel, and noise when the Rife-Vincent windows class I (the rectangular window, the Hann window, and others with higher order) are used. Simulations changing the bias of the amplitude DC coefficients support the analysis.