A study of sampled-data control systems

AN ANALYSIS OF sampled-data servomechanisms which is useful in system design is described in this article. A sampled-data system has a sampling device at some point in the transmission. A sampling device has an output which is related only to input samples which are taken at instants equally spaced in time. If θi(t) be the input signal to the device, then the output is related in a linear fashion to θi(nT), where n is any integer and the constant T is the length of time between samples. When the sampling device is put in the feed-forward section of a servomechanism, special stability problems arise which are not present in the conventional servomechanism with continuously supplied error data.