Réflectomètre à haute résolution

Measurement capabilities of a single mode optical time domain reflectometer (Otdr) are given. Fault location accuracy is 1 m (when the group index of refraction is known) and spatial resolution is 3 m.     

Sur une expression des puissances d’une matrice et son application aux réseaux itérés

Annals of Telecommunications - Après une brève introduction, dans unepremière partie, l’auteur donne (I), de lapuissance d’une matrice d’ordre 2, une expression...     

Étude et réalisation de modulateurs et de démodulateurs directs quadriphases pour la régénération à bord des satellites relais

This paper presents the study of a four phase remodulation demodulator which is part of a microwave signal regenerator for communications payload or data relay satellites. At first, 3.87 GHz biphase (bpsk) balanced modulator has been produced, using planar technology with slotlines and microstrip lines engraved on an Epsilam-type substrate, and two beam-lead Schottky diodes. Under modulation, carrier and even harmonic rejection of better than 50 dB is obtained, with insertion losses lower than 2 dB. A fourphase (qpsk) modulator is also produced using two bpsk modulators. Each phase state is achieved at ± 1.3° with 5.2 dB of insertion losses and a residual amplitude modulation of ± 0.14 dB. Carrier and even harmonic rejection of 45 dB is obtained.     

Performances des amplificateurs distribués en régime grand signal

This paper deals with the application of distributed amplifier as a power amplifier. Theoretical results obtained by using thespice II program will be presented and compared with measurements up to 12 GHz. It will be shown that small signal properties can be applied for large signal conditions. Large signal measurements give a constant gain of 6 dB in a frequency range from 1 to 10 GHz with an output power of 19 dBm.     

Décodage à sortie souple des réseaux de points

We present a universalmse algorithm for lattice decoding in dimensions up to 1024 for both Gaussian and Rayleigh fading channels. This algorithm can be applied to decode high diversity multidimensional rotations. The decoding is performed by a decision feedback equalizer and provides soft output which allows a concatenation of the lattice codes with other type of error-correcting codes. The problem of selecting a good rotation is also considered, and we show that a high dimensional random rotation exhibits very good performance on a Rayleigh fading channel.