V.Yu. Semenov – Ph.D.(Phys.-Mat.), Senior Lecturer,  Department of Radioengineering, Lobachevsky State University of Nizhni Novgorod Е-mail: vitali.semenov@gmail.com

A.A. Podkopaev – Post-Graduate Student, 
Department of Radioengineering, Lobachevsky State University of Nizhni Novgorod Е-mail: podkolpaev.anton@yandex.ru