3,917 research outputs found
Adolescencia y juventud. Entre los estereotipos y la construcción de la subjetividad
No full textFil: Butti, Federico, . Universidad Nacional de Villa María; Argentina
A chopper modulated low noise instrumentation amplifier for MEMS thermal sensors interfacing
No full textA CMOS instrumentation amplifier for interfacing integrated thermal sensors is proposed. It is based on a Gm-C 2nd order low pass filter, and exploits chopper modulation to improve its performances in terms of offset and low frequency noise. An input noise level of 10 nV/sqrt(Hz) and a current consumption of a few hundred of μA have been obtained by means of a careful design. Moreover, an original technique of input and feedback port swapping improves the amplifier gain precision. A prototype has been designed with the BCD6s STMicroelectronics process, and its functionality has been demonstrated by means of electrical simulations
An automatic procedure for the synthesis and optimization of very low-frequency Gm–C integrators
No full textFully integrated low frequency filters are critical
cells that should be carefully designed in order to avoid
excessive area occupation. In this work we propose an
automatic procedure capable of optimizing the design of
Gm–C integrators, which constitute the basis of a wide
class of Gm–C filters. The optimization target is minimizing
the cell area with constraints on input range and low
frequency noise. Lower and upper bounds can be fixed to
most quantities and design parameters in order to avoid
solutions that are not compatible with the physical limitations
of the process. The program has been developed
within the MATLAB
TM
platform, exploiting the optimization
toolbox. The effect of several important design
parameters on the optimization of low frequency integrators
has been investigated using the proposed routine. The
strong interaction between noise and low frequency constraints
has been demonstrated, showing the impressive
impact of strict noise specifications on the occupied area.
The actual effectiveness of parameters such as the current
division factor or approaches such as flicker noise rejection
by means of chopper modulation has been investigated.
Examples of integrator synthesis, performed using the
proposed procedure configured with the parameters of a
commercial CMOS process, are presented. The consistence
between the characteristics of the cells and the initial
specifications has been checked using electrical simulations
showing a maximum discrepancy with the initial specifications of nearly 80%. A semi-manual method to
refine the synthesized cells and improve the accuracy is
propose
Acoustic Velocity Sensors with Programmable DirectivitySensors
No full textA directional acoustical sensor with programmable axis of maximum sensitivity is described. The sensor is based on a combination of two orthogonal acoustical particle velocity (APV) sensors, integrated on the same chip. The APV sensors are based on a thermal transduction principle. Differently from former implementations, the proposed devices are fully CMOS compatible. Rotation of the sensitivity axis is obtained by combining the output of the two APV sensors properly weighted with programmable coefficients. This operation is performed using a microcontroller ADuC842 (Analog Devices) equipped with 12 bit, 400 kS ADCs
An automated area optimization routine for the design of very low frequency Gm-C integrators
No full textVery low frequency Gm-C filters are critical cells that should be carefully designed in order to avoid an excessive occupation of silicon area, especially when a high dynamic range is required. In this work we propose a routine, which exploits the MATLAB Optimization Toolbox in order to perform an optimum sizing of low frequency Gm-C integrators. The target is minimizing the integrator area, while satisfying design specifications such as unity gain frequency and dynamic range. Upper and lower bounds have been assigned to several design parameters to obtain solutions compatible with real processes. The interaction between noise and low frequency specifications has been investigated and their impact on the area occupation has been shown. The accuracy of the routine, configured with the parameters of a commercial process, has been shown using electrical simulations
CMOS Compatible Acoustic Particle Velocity Sensors
No full textIn this work we propose 2D acoustical particle
velocity (APV) sensors produced by post processing silicon chips
designed with the STMicroelectronics 0.32 μm BCD6s process.
The sensors consist of two conductive wires suspended on
dielectric membranes, separated by a 10 μm air gap. Heat
exchange between the wires, heated by an electrical current, is
modulated by the local velocity of the medium, producing
temperature oscillations, which are transformed into voltage
oscillations by the wire temperature coefficient of resistance
(TCR). Experimental characterization of the sensors, based on
the standing wave tube method, is presented
A Chopper Instrumentation Amplifier with Input Resistance Boosting by Means of Synchronous Dynamic Element Matching
No full textIn this work, we propose a method to increase the parasitic input resistance caused by application of chopper modulation to indirect current feedback instrumentation amplifiers. The result is obtained by applying dynamic element matching to the input and feedback ports at the same frequency as chopper modulation. The proposed approach requires effective offset ripple rejection and equalization of the input and feedback common mode voltages. An in-Amp architecture that meets both requirements and embodies the proposed input resistance boosting method is described. Experimental verification is provided by means of a prototype designed and fabricated using the 0.32mu text m CMOS devices of the STMicroelectronics BCD6s process. The amplifier operates with a 3.3 V supply voltage and a total current absorption of 170 mu text A. An input impedance in excess of 1 ext GOmega has been measured at a chopper frequency of 20 kHz. The input referred voltage noise density is 18 nV/sqrt(Hz) with a flicker corner of 0.2 Hz and 200 Hz bandwidth
Area optimization of very low-frequency Gm-C filters
No full textFully integrated low frequency filters are critical cells that should be carefully designed in order to avoid excessive area occupation. In this work we propose an automatic procedure capable of optimizing the design of Gm-C integrators, constituting the basis of a wide class of Gm-C filters. The optimization target is minimizing the cell area with constraints on input range and low frequency noise. The procedure is exploited to show the effect of various design constraints on important filter parameters. Verification with the result of electrical simulations is included
E. A. Butti : portrait d'un écrivain mineur
No full textIn the panorama of Italian literature at the end of the nineteenth century Enrico Annibale Butti (Milan 1868 - Milan 1912) has a more than minor place. Born in the same decade as Federico De Roberto (1861), Italo Svevo (1861), Gabriele D'Annunzio (1863) and Luigi Pirandello (1867), he is known mainly for his dramas, performed from 1890, and whose most noted are Fiamme nell'ombra (1904) and Lucifero (1901). Before devoting himself to theater - around twenty plays performed between 1889 and 1913 - he wrote five psychological novels: L'immorale (written in 1889, published five years later), L'automa (1892), L'anima (1893), L'incantesimo (1897), including one unfinished: L'ombra della croce (1905). The thesis covers his entire literary production and provides new elements on the author's biography. An important place is reserved for the research of his unlisted texts: news, articles, diary. Butti is put in contact with other writers of the same period, and a reflection is carried out on his role in Italian and French literature. In the thesis the reasons which determined his exclusion from the history of literature are studied and the emblematic portrait of this minor writer is drawn up.Dans le panorama de la littérature italienne de la fin du dix-neuvième siècle Enrico Annibale Butti (Milan 1868 - Milan 1912) a une place plus que mineure. Né dans la même décennie que Federico De Roberto (1861), Italo Svevo (1861), Gabriele D'Annunzio (1863) et Luigi Pirandello (1867), il est connu principalement par ses drames, représentés à partir de 1890, et dont les plus remarqués sont Fiamme nell'ombra (1904) et Lucifero (1901). Avant de se consacrer au théâtre - environ vingt pièces représentées entre 1889 et 1913 - il écrit cinq romans psychologiques : L'immorale (écrit en 1889, publié cinq ans plus tard), L'automa (1892), L'anima (1893), L'incantesimo (1897), dont un inachevé : L'ombra della croce (1905). La thèse porte sur l'ensemble de sa production littéraire et fournit de nouveaux éléments sur la biographie de l'auteur. Une place importante est réservée à la recherche de ses textes non répertoriés : nouvelles, articles, journal intime. Butti est mis en relation avec d'autres écrivains de la même époque, et une réflexion est menée sur son rôle dans la littérature italienne et française. Dans la thèse sont étudiées les raisons qui ont déterminé sa mise à l'écart de l'histoire de la littérature et est dressé le portrait emblématique de cet écrivain mineur
Smart Flow Sensors Based on Advanced Packaging Techniques Applied to Single Chip Sensing Devices
No full textA smart flow sensor capable of measuring two distinct gas flows with two different linearity ranges is proposed. The device is based on a chip, designed with a commercial CMOS process, which includes different sensing structures and a read-out interface. The chip is fabricated applying a post-processing technique based on a silicon anisotropic etching in a TMAH solution. A simple and low cost packaging technique is used to convey two distinct gas flows to two selected sensing structures by means of channels of different cross sections. Three methods for sealing the interface between the chip and the gas conveyor are proposed and discussed
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