The analysis of sampled data servomechanisms performed on the IBM Type 650

Because of the need for more accurate and versatile control capabilities than can be obtained economically with continuous systems, discrete filters (digital computers) are being substituted as control elements in many applications. The exact response of linear systems which combine continuous and discrete filters can be obtained for discrete values of time by a series of well-defined mathematical processes. Since these processes require many computations of a repetitive nature to obtain complete response data, manual methods of computing are often not practicable and general-purpose digital computers such as the IBM (International Business Machines Corporation) type 650 are used to assist in the analysis of these systems.