I.M. Moiseenko – Ph.D. (Phys.-Math.), Junior Research Scientist, 

Saratov Branch of Kotelnikov Institute of Radio Engineering and Electronics

E-mail: MoiseenkoIM@yandex.ru

V.V. Popov – Dr.Sc. (Phys.-Math.), Head of Laboratory, 

Saratov Branch Kotelnikov Institute of Radio Engineering and Electronics

D.V. Fateev – Ph.D. (Phys.-Math.), Senior Research Scientist,

Saratov Branch Kotelnikov Institute of Radio Engineering and Electronics; Saratov State University