Securing Programmable Analog ICs Against Piracy

International audienceIn this paper, we demonstrate a security approach for the class of highly-programmable analog Integrated Circuits (ICs) that can be used as a countermeasure for unauthorized chip use and piracy. The approach relies on functionality locking, i.e. a lock mechanism is introduced into the design such that unless the correct key is provided the functionality breaks. We show that for highly-programmable analog ICs the programmable fabric can naturally be used as the lock mechanism. We demonstrate the approach on a multi-standard RF receiver with configuration settings of 64-bit words

Effect of Periodontal Surgery on Tissue Plasminogen Activator and Plasminogen Activator Inhibitor Type-1 Gene Expression in Gingival Tissues of Periodontitis Patients: A Controlled Before-And-After Study

Background: Regulation of the plasminogen activation system (PAS) is a vital component in governing proteolytic events within the extracellular matrix (ECM). PAS is believed to play a substantial role in the destruction and healing of periodontal tissues. Thus, the current work aimed to study the histopathological effect of open flap debridement (OFD) on periodontitis, as well as its effect on tissue plasminogen activator (t-PA) and plasminogen activator inhibitor type-1 (PAI-1) gene levels in gingival tissues. Methods: A total of 30 subjects were enrolled in the present study. They were divided into two groups: Group I (control group) included 10 periodontally healthy volunteers and group II (periodontitis group) comprised 20 patients suffering from stage III grade B periodontitis. Gingival tissue samples were collected from all periodontitis patients, before and after OFD, and from healthy controls. Hematoxylin and eosin (H&E) stained slides were subsequently examined and gene expression levels of t-PA and PAI-1 were assessed in the gingiva through quantitative reverse transcription polymerase chain reaction (RT-PCR). Results: Gingival tissue samples from periodontitis patients showed dilated blood vessels, diffuse hemorrhage, areas of edema, and disorganized collagen fibers together with large amounts of inflammatory cells in between.  Following OFD, smaller sized blood vessels, a restored collagen fiber distribution, and an obvious decrease in the inflammatory infiltrate were noted. Gene expression levels of t-PA and PAI-1 were significantly higher in the periodontitis patients compared to the healthy controls. Although their levels showed a significant decrease following OFD in the periodontitis group, they were still significantly higher than the control group. Conclusion: OFD procedures resulted in down regulation of t-PA and PAI-1 expression levels in the gingiva of periodontitis patients, which could signify an important role of these proteins on periodontal disease progression

Automatic Design of RF Linear Transconductor

International audienceThis work proposes a methodology to design linear transconductors based on three circuit topologies previously reported in literature. The design is done to be used in a synthesis tool, containing the MOS transistor model. The topologies has been analyzed using a more improved small-signal equivalent circuit of a MOS transistor to obtain a more accurate expression for the transconductance (Gm) and to extend the use for high frequencies range. A design examples in 945Mhz is given in a 130nm CMOS process

RF receiver for software-defined radio based on bandpass sigma-delta analog-to-digital converter

PARIS-BIUSJ-Mathématiques rech (751052111) / SudocSudocFranceF

Fast and accurate jitter simulation technique for continuous-time ΣΔ modulators

International audienceA fast and accurate technique for modelling and simulation of clock jitter in continuous-time sigma-delta (SigmaDelta) modulators is introduced. In addition to its high speed compared to the traditional jitter simulation method, the proposed technique is still continuous-time based, which is more convenient than discrete-time based jitter modelling suggested in other publications. The mathematical principle of the proposed technique, as well as simulations results, are presented and compared to other simulation techniques

Simple architecture for subsampling LC-based ΣΔ modulators

International audienceA simple architecture for subsampling LC-based continuous-time ΣΔ modulators is introduced. The concept of utilising loop delay to simplify the modulator architecture is generalised to subsampling modulators. Moreover, it is shown that is possible to remove the delay-compensation branch usually used in traditional designs. Removing the delay-compensation branch results in significant simplification of the modulator architecture, and eliminates several problems usually associated with the delay-compensation branch

Environnement de conception multi-niveaux unifiée appliqué aux systèmes mixtes

Ce travail se place dans le contexte de la conception, la modélisation et la simulation de systèmes hétérogènes contenant a la fois des capteurs, des composants analogiques, des composants numériques et des circuits RF.La seule manière de simuler un système avec une telle complexité avec un temps de simulation raisonnable est de faire une modélisation haut niveau.Cependant, pour que ce modèle haut niveau soit fiable, les modèles des blocs analogiques et RF doivent contenir une description précise des leurs imperfections.Dans ce travail nous proposons une méthode systématique pour la caractérisation et le raffinement des modèles des blocs analogiques et RF.Cette méthode est réalisée dans un environnement C++ base sur: - l'outil de simulation haut niveau SystemC-AMS- l'outil de résolution d'expression symbolique GiNaC- l'outil de synthèse de circuits intégrés analogique CAIRO+/CHAMSPour illustrer la validité de la méthode proposée, nous présenterons le modèle d'un nœud d'un réseau de capteurs sans fil avec une caractérisation automatique de certains blocs analogiques et RF.Les points suivant résument les contributions apportées pour ce travail.- La première implémentation d'un modèle analogique numérique mixte complexe avec le langage SystemC AMS: un nœud de réseau de capteurs sans fil.- L'introduction du raffinement pour une approche générique des modèles au niveau système.- Un outil d'évaluation précise des performances linéaires et non-linéaires des circuit analogiques pour le raffinement des modèles niveau système et l'optimisation de la conception niveau circuit.- Une méthodologie de conception niveau circuit basée sur des outils de dimensionnement et d'évaluation des performances avec précision.- Un environnement de conception multi-niveaux unifiée appliqué aux systèmes mixtes avec une très forte interaction entre la simulation niveau système et la conception optimisée niveau circuit.PARIS-BIUSJ-Mathématiques rech (751052111) / SudocSudocFranceF

Using excess loop delay to simplify LC-based ΣΔ modulators

International audienceThe excess loop delay in continuous-time LC-based ΣΔ modulators, which usually has negative effect on the stability and the signal-to-noise ratio of the modulator, can be used to simplify the modulator architecture and reduce the number of needed feedback branches. The proposed technique is discussed and validated using a design example of a fourth-order bandpass continuous-time LC-based modulator