Vestnik of Samara State Technical University. Technical Sciences SeriesVestnik of Samara State Technical University. Technical Sciences Series1991-85422712-8938Samara State Technical University2011210.14498/tech.2015.3.%uResearch ArticleStability analysis of positional servo actuator taking into account the discreteness of the zero-order extrapolatorLysovVladimir E(Dr. Sci. (Techn.)), Professor-SidorovIgor SPostgraduate Student-Samara State Technical University1510201523314214810022020Copyright © 2015, Samara State Technical University2015The Kotelnikov-Shennon theorem proves the possibility of data recovery from digital signal if the sampling frequency is the frequency of discrete elements is more or is equal to the doubled sampling frequency . This is true if sampling frequency has limitations. However, in real systems, with a tend to infinite value the effect of Aliasing is shown, which distorts the information. In this regard, the influence of discrete digital system introduces an additional error, which degrades the system specifications. The purpose of the paper is to analyze the impact of discreteness brought by an extrapolators of a zero order as a part of automatic control system on the system error.the period of discretenessthe zero-order extrapolatordigital systemindicators of control gualityпериод дискретностиэкстраполятор нулевого порядкацифровая системапоказатели качества управления[Рапопорт Э.Я.Системы подчиненного регулирования электроприводов постоянного тока: Конспект лекций. - Куйбышев, 1985. -56с.][Иващенко Н.Н.Автоматическое регулирование. Теория и элементы систем. - М.:Машиностроение, 1978.-736с.][Теория систем автоматического управления/ В.А. Бесекерский, Е.П.Попов. -СПб.: Профессия, 2003.-740с.][Лысов В.Е. Теория автоматического управления. - М.:Машиностроение,2010.-500с.][Руководство по характеризации УЧПУ. - СПб., 2010. - 145с.]