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The authors here propose, for the first time, an automatic analog interface for differential capacitance estimation, able to reveal and quantify both low and high (full-range) capacitive variations. The working principle is based on a modified De-Sauty AC bridge configuration where two differential capacitances and two resistances are employed, one of which is implemented by a Voltage Controlled Resistor (VCR). Through a suitable feedback loop, a very accurate estimation over the complete range of the differential capacitance variation is possible, while the bridge allows a continuous differential capacitance evaluation without the need of knowing the accurate value of the sensor baseline and/or its variation range. A general but very simple formula, considering both the “autobalancing” and the “out-of-equilibrium” ranges, is also given. Theoretical, experimental and simulated results are in a very good agreement. Sensitivity and resolution values, typical of sensors and their interfaces, have been determined in a practical case, showing satisfactory values. [ABSTRACT FROM AUTHOR]

In this paper we propose a new versatile full wave rectifier circuit using voltage conveyor (VCs) as active blocks. The proposed circuit uses two VCs, a single grounded resistor and two diodes. Compared to other previously reported rectifier circuits, it shows a simple and compact structure, employing the minimum possible number of elements. Moreover, the rectified output is available in forms of both voltage and current signals, at low impedance voltage output Z port and high impedance X port of VC, respectively. Therefore, for practical use, the proposed rectifier is cascadable without the need for extra voltage and current buffers. In addition, also the input signal can be applied in both forms of a current and of a voltage. To validate the presented theory, SPICE simulations, using 0.35 µm CMOS technology parameters and supply voltage of ±1.65 V, are reported, together with a set of measurements conducted over an equivalent discrete-level circuit, where AD844s were used to mimic VCs behavior. [ABSTRACT FROM AUTHOR]

Abstract: In avionics application it’s fundamental that each system, sub-system or a component achieves a high level of reliability. To this aim, reliability prediction and an accurate test planning are required in the design phase in order to avoid undesirable fault or failure during the operating life cycle of any aeronautics equipment. In this paper, a research activity concerning the design and reliability assessment of TFT–LCD for avionics application is presented. The results obtained by the development, characterization and reliability analysis of a customize display which will be installed in a military aircraft cockpit are discussed. As the device under test is an innovative display, an evaluation and analysis of the reliability performances is essential. Tests on the display have been implemented to validate the customizing process. [Copyright &y& Elsevier]

Capacitive multipliers have found wide applications in capacitive interfaces and other analog circuits requiring large value capacitors. Recently a new active building block (ABB) called second generation voltage conveyor (VCII) has been proved to be useful in many analog signal processing applications. Due to the interesting features offered by VCII, in this paper a new VCII based implementation of grounded capacitance multiplier is proposed employing two VCIIs, two resistors and one grounded capacitor. The circuit can produce both positive and negative multiplication factors in a range of −50 to +50. Its main features are wide frequency range, high resolution, low series resistance, simple structure, low power consumption and maximum percentage error of 7.8%. The circuit enjoys high frequency range up to 10 MHz, even if it employs a floating capacitor in its structure. The behavior of the proposed circuit is analysed by taking into account also the effects of VCII parasitic elements and non-ideal gains. SPICE simulation results using a 0.35 µm CMOS technology parameters are reported. The proposed circuit has been also experimentally tested by using AD844 as VCII. Measurement results on the standalone capacitance multiplier have shown a mean percentage error of 9% across the entire gain range. Finally, the application of the proposed circuit in realizing a low pass filter is also presented to demonstrate the proposed circuit feasibility. [ABSTRACT FROM AUTHOR]

We here present a current mode Instrumentation Amplifier (IA) based on second generation current conveyor (CCII) with complete input/output dynamic range (rail-to-rail) and constant-g m characteristics. The IA operates at 1.5 V supply with 177 μW power consumption, high-loop gain (115 dB) and high CMRR (105 dB). The proposed IA has been implemented by using a standard AMS 0.35-μm CMOS technology. SPICE simulations are also reported. [ABSTRACT FROM AUTHOR]

Avionics represents of the most important industrial sector where innovation is a key issue. In order to guarantee that any new device introduced onboard has an adequate quality and reliability level, testing activity is fundamental to help engineers and technicians to verify their designs and prevent any safety critical failures. National regulatory agencies and standards organizations, such as, the European Union Authority for aviation safety (European Aviation Safety Agency – EASA), the United States defense standard, often called military standard (MIL-STD) carried out by the U.S. Department of Defense or the Radio Technical Commission for Aeronautics (RTCA), have developed several test procedures that have to manage with the customer requirements. This paper is focused on the experimental results related to the validation process of a custom TFT-LCD for avionics applications. Environmental tests and, in particular, optical measurements will be described in detail in order to underline the key role that test plannig and measurements represent in aerospace applications. [ABSTRACT FROM AUTHOR]