D.A. Lampasi

The Generalized Lambda Distribution for the Expression of Measurement Uncertainty

The generalized lambda distribution family fits the probability distributions of a wide variety of data sets, including the most important distributions in measurement applications (normal, uniform, students t, U-shaped, exponential). This paper illustrates how the representation of measurement uncertainty by means of the four parameters of the distribution can extend the information about the results of a measurement and their uncertainty. Such representation allows an immediate calculation of coverage intervals and is particularly able to support the techniques commonly applied in estimation of combined uncertainty. Moreover, in order to include the classical measurement information, a novel X-parametrization is proposed

Accurate Digital Synthesis of Sinewaves

This paper discusses the digital synthesis of spectrally pure sinusoidal signals. A modified Sigma-Delta topology consisting of a digital-to-analog converter (DAC), an analog-to-digital converter (ADC), and an analog filter is adopted to efficiently estimate and compensate the DAC nonidealities while desensitizing the system to those of the remaining elements. The proposed correction procedure was implemented on a digital signal processing board equipped with general-purpose data converters. It is shown that the technique can improve the spurious-free dynamic range of the generated signals without requiring high-performance measurement equipment.

Modular Architecture for Remote Management of Powe Generation Plants

This paper describes a network architecture to remotely monitor and control complex power generation plants. Such architecture was designed as a sequence of independent blocks, in order to allow the interchangeability among elements belonging to the same block type. The resulting systems can be adapted to the particular plant, the available communication media and the sustainable costs. The architecture and the proposed solutions were applied to two types of generation plants, based on photovoltaic and wind micro-generators

A new structure of transparent films for heat control and electromagnetic shielding of windows

Experimental tests highlight that transparent films used for thermal control in windows can be successfully adopted to obtain electromagnetic shielding in the radio frequency range. New multifunctional sandwich-structures consisting of commercial films over a glass layer are investigated. Electromagnetic, optical, and thermal performances are predicted and optimized by using the developed simulation codes. Numerical and measured frequency spectra of the shielding effectiveness and optical transmittance of the realized multilayer structures are shown.

Binary Sequences with Good Spectral Properties Obtained by Genetic Algorithms

This paper describes a novel method for the digital synthesis of high quality signals by means of one-bit digital-to-analog converters. The aim of the paper is the individuation of the best binary sequences for signal generation and the analysis of their properties. Such sequences are obtained by genetic algorithms, either independently of a physical implementation of the analog-to-digital converter, or by optimizing the parameters of an oversampled conversion

Design and characterization of optical filters for EM shielding

This paper describes a technological approach for the realization of frequency selective shielding coatings characterized by high optical transmittance in the infrared region. The adopted method consists in sputtering a multilayer thin film and afterwards patterning the obtained coating by laser ablation. The geometry of the desired pattern was designed to improve the optical performances without losing the radio frequency shielding properties. The results of the characterization performed on a laboratory-scale prototype coating are presented.

Expression of Measurement Uncertainty in Quantile Domain

This paper proposes a novel approach to measurement uncertainty developed in the framework of the probability theory and based on the concept of quantile and related techniques. The conversion of measurement-related activities to the quantile domain extends the information expressed by metrological parameters and, at the same time, simplifies their management.

Distributed Network for Accurate Indoor Localization of Mobile Phones

The availability of a system to detect and localize mobile phones and portable electronic devices may be useful in many situations, generally corresponding to indoor environments. This paper describes a distributed system for the localization of mobile phones that can be extended to the detection of other portable electronic devices. It is based on a small low-cost sensing units developed to this purpose. Due to the peculiarity and variability of the emitting sources, of the adopted principles, and of the considered environments, the electromagnetic characterization of the system was referred to novel statistical parameters defined in a loaded reverberation chamber. The results of some experimental tests concerning the whole system and the single elements are also presented.

Loopback Test and Error Correction of Data Converters

The loopback test consists in the connection of an analog- to-digital and a digital-to-analog converter using suitable filters. By using particular loop structures, such approach allows to isolate and correct the non-idealities of only one of the converters, generating highly spectrally pure signals. A novel approach is proposed, which shifts the frequency selectivity into the digital domain. The performance in terms of accuracy and dynamic range of the techniques based on these principles are characterized and optimized.

Electromagnetic Characterization of a Field Sensor for the Localization of GSM Cellular Phones Aboard an Aircraft

This paper describes an innovative test procedure for the characterization of a new field sensor prototype sensitive to amplitude-modulated signals and designed to be installed as a detector unit in an intelligent network for the localization of global system for mobile communications (GSM) cellular phones aboard an aircraft. The response of the sensor, expressed by the activation probability in a given operative condition, is obtained as a function of frequency, voltage supply, and incident field level.