P.P. Aseev - - Ph.D. (Phys.-Math.), Junior Research Scientist, Kotelnikov IRE RAS (Moscow). Е-mail: pavel.p.aseev@gmail.com V.O. Kaladzhyan - Post-graduate Student, Kotelnikov IRE RAS (Moscow). Е-mail: vardashka@gmail.com S.N. Artemenko - Dr.Sc. (Phys.-Math.), Kotelnikov IRE RAS (Moscow). Е-mail: art@cplire.ru