O.V. Tcvetkov - Dr. Sc. (Eng.), Professor, Department of Biotechnical Systems, Saint-Petersburg Electrotechnical University «LETI» E-mail: ovts@bk.ru Yu. O. Bobrova - Post-graduate Student, Department of Biotechnical Systems, Saint-Petersburg Electrotechnical University «LETI» E-mail: yul.bobrova@gmail.com