V.A. Tsarev - Dr. Sc. (Eng.), Professor, Department «Electronic Devises and Equipment», Yuri Gagarin State Technical University of Saratov. E-mail: tsarev_va@mail.ru D.A. Nesterov - Post-graduate Student, Department «Electronic Devises and Equipment», Yuri Gagarin State Technical University of Saratov. E-mail: enlucioro@gmail.com