Determination of periodic modes in relay servo-mechanisms employing sampled data

A difference equation approach is presented to determine the periodic modes in relay servomechanisms employing sampled data. In using the method, together with Izawa and Weaver's method, the investigator can have all the information concerning possible periodic modes of a system. This new technique is based on expressing periodic sequences in terms of orthogonal functions in the discrete sense and balancing the harmonics.