Chérif El Valid Diouf

Statically constrained nonlinear models with application to IC buffers

Volterra series are well known approaches to modeling non-linear systems. In recent works a properly weighted combination of Volterra models have been used to successfully mimic the behavior of the output port of an integrated circuit buffer. The current paper focuses on a novel mechanism for controlling the static characteristic of such models. A commercial driver example is used to illustrate the efficiency of the technique to guarantee accurate static levels during time-domain simulations.

Simplified topology for integrated circuit buffer behavioural models

This paper addresses the behavioural modelling of digital integrated circuit buffers for performance assessment of high-speed data links. A new modelling technique, with several important advantages is described. All the requirements of black-box identification are met: the approach relies exclusively on the observation of the external port voltages and currents, thus allowing the extraction of models that mimic the operation of real devices without insight on their internal structure. Furthermore, unlike the standard algorithms currently used in EDA tools, the method described in this study provides a straightforward solution to modelling the input-output behaviour. Good model performance in overclocking conditions is an important advantage. This study also investigates the possibility of accounting for power-supply voltage variations and provides a simple solution.

On the Use of Equality Constraints in the Identification of Volterra–Laguerre Models

This letter focuses on the a posteriori correction of Volterra-Laguerre models in order to meet specific static or dynamic requirements. The authors set a general theoretical framework and provide an illustrative example.

A Joint Linearization/Companding Approach for Improving a CO-OFDM Transmitter

The joint use of peak-to-average power ratio (PAPR) reduction and linearization via digital predistortion is investigated in this letter, with the view to improve the performances of coherent optical OFDM systems employing a semiconductor optical amplifier. The PAPR reduction is performed via Wangs nonlinear companding transform, which has been recently pointed out as a pertinent choice for optical communications, and a filter lookup table scheme is considered for linearizing the transmitter. Experimental results prove the effectiveness of the proposed scheme, as a lower error vector magnitude is achieved with respect to system implementations using only the PAPR reduction or linearization.

A bidirectional and versatile power-over-fiber system for seafloor observatories

A Power-over-fiber extension for an existing fixed seabed observatory is presented in this contribution. The system is characterized by its versatility in respect to the sensors with which it can operate. Turbidimetry tests and results are presented.