Réalisation d’un opérateur de traitement numérique rapide par une machine à flux de données

The authors describe a fast, parallel and static data flow architecture that is used for Fast Riccati Operator (Fro)design. This operator has a cellular, regular structure easy to integrate, and is intended to resolve with high speed execution the matrix Riccati equation for filtering purpose. To evaluate its performances, two solving algorithms, Lindquist and quasilinéarisation, are represented and simulated by data flow Petri nets, defined for this purpose. Simulation results are compared to real needs in search and tracking situations.     

Étude théorique et expérimentale d’un synchronisateur primaire numérique pour signaux MIC

Bit synchronizers are used in satellite data communications systems to restore the data rate. They provide means to data detection. The paper concerns the theoretical analysis supported by the simulation and the pratical measurements of a digital self bit synchronizer implemented with standart ttl logic. This self bit synchronizer is composed of a non linear element which delivers from the sampled and quantized pcm signal a spectral line at frequency twice the data rate. This spectral line is filtered by a digital phase locked loop and is used to drive a digital matched filter data detector. Theoretical and experimental results show a very small mean acquisition time (about 4 or 5 bit duration) and a degradation lower than 2 dB for snr ranging from +2 dB to +12 dB.     

Étude théorique et expérimentale d’une modulation simplifiée par déplacement de fréquence d’indice 1/2 à phase continue

The minimum shift keying modulation (MSK)to which a lot of recent publications have been done,presents some advantage about linear and non-linear distortions towards common 2 or 4 Phase Shift Keying (PSK)modulations. The simplified MSK modulation described in this paper is obtained by linear filtering of a coherent 2 phase shift keying modulation. Then the demodulator can be implemented with a matched filter followed by a coherent demodulator using only one carrier recovery circuit. In the first part of this paper, the modulator and the demodulator are described. After, some theorical results in the presence of noise and other impairments are given. In CCETT laboratories at Rennes, a modem has been realized at a data rate of 2,048 Mbit/s and performs at 0,8 dB of the theoretical results.     

Étude du couplage d’une onde électromagnétique externe et d’une ligne de transmission aérienne non uniforme

In this paper, a flexible and efficient method for analyzing the electromagnetic field to nonuniform multiwire aerial lines coupling is proposed. This analysis in based upon the finite- difference time- domain (fdtd) algorithm. The transient responses of nonuniform lines excited by different waves obtained by this method are compared with those of Spice and literature. The good agreement between all the simulation results validates the proposed approach.     

Étude temporelle du couplage d’une onde

This paper deals with a temporal approach of interaction between an external electromagnetic wave and an arbitrary multiconductor transmission lines (Mtl). The loads of the circuits can be linear like resistance elements or non linear as is the case of field effect transistor (Mesfet). The numerical technique used is the finite differences time domain (Fdtd) witch givesMtl temporal responses with good stability. Good agreement between the results obtained by the proposed method and those by literature and Spice model verifies the validity of theFdtd algorithm.     

Compression de données brutes et d’images de radar à synthèse d’ouverture

This paper draws a state of the art of synthetic aperture radar (sar) data compression. Both raw data and synthesized image compression have been investigated. Compression of radar raw signal and sar image are considered separately since those two cases are specific. Also, Radar raw/image compression remains different from optical image compression and has to be considered with specific strategies that are adapted to the context.     

Étude du comportement d’une boucle de Costas en modulation MAQ 16 en présence d’évanouissements sélectifs

This paper gives the variance of the phase recovered by a conventional quadriphase Costas loop in 16 Qam modulation in the presence of a selective fading, represented as a three rays simplified model. The power spectral density of the phase error is computed using a spectral estimation technique. The phase error variance is evaluated for different values of the fade depth, the location of the maximum attenuation in the frequency band and the delay of the reflected ray. Finally the relation between the performance degradation and phase noise is given, assuming a gaussian p.d.f. of the phase error.     

Démarche de conception d’une plate-forme monopuce de réception de radiodiffusion numérique DRM

The newdrm standard for digital radio broadcast in theam band requires integrated devices for radio receivers at low cost and very low power. A chipset has been developed based on anarm9 dual-core architecture. This paper introduces the application itself, and then presents the development process followed to design such a chip covering the hardware/software partitioning, the architecture definition and all the validation issues. Therf part that partially drives the baseband is also briefly presented. The legal aspects are also investigated. Then as a conclusion, this paper presents the next steps of this development and the methodological gap in the system on chip design process.