Maurizio Caciotta

Power quality measurements in telecommunication exchanges

This work shows an example of power quality (PQ) data of four important telecommunication sites placed in Rome, Italy. The data are collected, elaborated and analyzed by four self made instruments developed for this purpose and inserted in four automatic telecommunication exchanges kindly at our disposal by TELECOM, the most important Italian telecommunication company. The analysis shows the active and reactive power consumption and, for one site, the harmonic distortion.

Orthonormal Gas-Chromatography Sets of Extra Virgin Olive Oil

Starting from gas-chromatograms of extra virgin olive oil samples, choosing the most significant peaks, authors try to define a standard ortho-normal base to be deposited for quality valuation.

Stochastic-flash analog-to-digital conversion

Flash-type analog-to-digital converters (ADCs) presenting a nonlinear behavior, i.e., having nonequally spaced threshold levels, may introduce harmonic distortion that can be reduced by employing large-amplitude dither-based conversion techniques. However, large-scale dithering is difficult to implement and, in addition, severely reduces the ADC input dynamic range. In this paper, a new ADC architecture is presented based on ordinary flash conversion and dynamic element matching, that strongly reduces nonlinear distortion. It eliminates the need for large-scale dither signals by randomizing the resistor positions in the resistor string used to generate the voltage references. Some properties of this architecture are analyzed and simulation results that validate the theoretical assumptions are presented.

A New Dusts Sensor for Cultural Heritage Applications Based on Image Processing

In this paper, we propose a new sensor for the detection and analysis of dusts (seen as powders and fibers) in indoor environments, especially designed for applications in the field of Cultural Heritage or in other contexts where the presence of dust requires special care (surgery, clean rooms, etc.). The presented system relies on image processing techniques (enhancement, noise reduction, segmentation, metrics analysis) and it allows obtaining both qualitative and quantitative information on the accumulation of dust. This information aims to identify the geometric and topological features of the elements of the deposit. The curators can use this information in order to design suitable prevention and maintenance actions for objects and environments. The sensor consists of simple and relatively cheap tools, based on a high-resolution image acquisition system, a preprocessing software to improve the captured image and an analysis algorithm for the feature extraction and the classification of the elements of the dust deposit. We carried out some tests in order to validate the system operation. These tests were performed within the Sistine Chapel in the Vatican Museums, showing the good performance of the proposed sensor in terms of execution time and classification accuracy.

Study of a New GPS-Carriers Based Time Reference with High Instantaneous Accuracy

A possibility to obtain a new time reference constantly locked to the Caesium-derived GPS satellites carriers was investigated by means of a new GPS receiver architecture able to lock the two GPS carriers and mix them to obtain a reference frequency with an accuracy close to the GPS one. This is very important in Perceived Power Quality distributed measurements systems where the exact knowledge of the events on the geographic compass is strongly joined to the capability to associate them an accurate time. A simulation of the carrier tracking loop has been performed. It shows how choosing appropriately the frequency of the low-pass filter of Costas loop, a modified PLL typically used in GPS system, it is possible to recover carriers in presence of high noise to signal ratio too. The front-end of the system able to select GPS frequencies, which is the first block of the entire system, was also realized.

Digital signal generator for real-time FPGA power quality alghoritm test

This paper proposes an FPGA based device implementing a signal generator for power quality analysis. The device simulates the behavior of an ADC connected to the power grid. Its main goal is to make it easy to have real-time tests on algorithms implemented on embedded hardware.

Development of an USB data acquisition system for Power Quality and smart metering applications

Starting from a previous work, a new Data Acquisition USB Device has been designed, developed, realized and characterized to be used in Power Quality and Smart Grid applications. The system simultaneously manages 8 data acquisition channels to allow voltages and currents monitoring on tri-phases lines. It can get external both certified time and voltage references to warranty certified measurements, but it also use internal references for non certified ones. The USB card is in PCI form factor and can be placed inside a common PC slot or in external shielded housing. FTDI Virtual ComPort drivers yield to a flexible multiplatform device, without requiring any advanced programming skill. The proposed device has been tested with custom software written in C# and VB6 languages, moreover it has been characterized applying the most common ADC performing test to verify its behavior.

A multi-platform Data Acquisition Device for Power Quality metrological certification

A Data Acquisition USB Device has been realized to be used in Power Quality monitoring activities. The adopted solution allows to perform 8 channel simultaneous data acquisition with external certified time and voltage references, working at 499 samples per 50 Hz period. The self-powered USB interface combined to multiplatform FTDI Virtual ComPort drivers yields a simple-to-use and scalable device; it can be driven simply sending and receiving data over High Speed RS232 virtual interfaces, without requiring any advanced programming skill. The virtual serial communication makes data acquisition software portable over many platforms, regardless development environment and programming language. The proposed device has been tested with custom software written in C# and VB6, than in LabView and MatLab environment.

A system for obtaining a frequency reference constantly locked to L1 GPS carrier for distributed power quality assessment

The need to deploy distributed power quality monitoring systems requires the development of circuits able to yield an accurate time reference that is easy to disseminate on specific monitoring sites. In this paper, the design and initial realization of a time reference continuously traceable to a Cs133 atomic standard is proposed. Such reference is based on the locking of the Cesium-derived L1 GPS satellites carrier and would simply require visibility of one GPS satellite in order to be operative. In particular, attention is focused on the hybrid design and realization of the carrier tracking section, with particular emphasis on its fundamental building blocks, such as the voltage controlled oscillator, mixers, and power dividers. The design procedure for the different blocks and some prototypes are discussed and preliminary measurements showing their functionality are presented.

Design and characterization of a stochastic-flash ADC

In this paper, the design and characterization of a 7-bit CMOS stochastic-flash analog-to-digital converter is illustrated by means of simulations including level-3 CMOS models and estimated dither-based spectra. The conversion scheme and its main properties are briefly recalled, and a possible design of the voltage reference generator proposed. It is shown that mismatches among the resistors in the ladder employed to generate these voltages are largely compensated by the presented architecture when small-scale dithering is employed.