1. Laboratory of Electronics and of Signal Processing, Department of Physics, Faculty of Science, University of Dschang, P.O. Box 67, Dschang, Cameroon
2. Research Group on Experimental and Applied Physics for Sustainable Development (EAPhySuD), P.O. Box 412, Dschang, Cameroon
3. Laboratoire de Mécanique et de Modélisation des Systèmes, Département de Physique, Faculté des Sciences, Université de Dschang, B.P. 67, Dschang, Cameroon