Adaptive Noise Cancellation for a Class of Non-Linear IIR Filters

A new filter structure known as the NARMAX model (Nonlinear AutoRegressive Moving Average model with eXogenous inputs)is introduced as a basis for the design of a class of nonlinear filters which can be used for noise cancellation. The new design is an extension of the classical IIR filter and it is shown that the filter parameters can be estimated using a suboptimal least squares algorithm originally developed for system identification. Conditions for the convergence of the algorithm are briefly discussed and simulation results are presented which show the effectiveness of the new structure

Optimization of Unsupervised Classification by Evolutionary Strategies

ABSTRACT The kmeans algorithm is an unsupervised classification algorithm. This algorithm however, suffers from two difficulties which are the initialization phase and the local optimums. We present in this paper some improvements to this algorithm based on the evolutionary strategies in order to get around these two difficulties. We have designed a new evolutionist kmeans algorithm. We have proposed a new mutation operator in order for the algorithm to avoid local solutions and to converge to the global solution for a low computational time. This approach is validated on some simulation examples. The experimental results obtained confirm the rapidity of convergence and the good performances of the proposed algorithm

PSPICE model of the power LDMOS transistor for radio frequency applications in the 1.8 – 2.2 GHz Band

In this paper, we propose a model for the LDMOS transistor used for power amplification in the frequencies band 1.8–2.2 GHz dedicated to the mobile telephony system Digital Cellular System (DCS). This model takes into account the behaviour of each internal region of the power structure. A new representation of the non-linear inter-electrode capacitances, drain-gate Cgd and drain-source Cds, is proposed. The obtained model is implemented in the circuit simulator PSPICE, which gives an overall evaluation of the transistor performances in the radio frequency power amplification mode. This model is Maynly intended to the system designer. A study of the power amplification in the SHF band at 2 GHz is performed. A good agreement between experimental and simulation results is found