Simple behavioral model of a recording device using a second-order non-linear recursive filter

A method to analyze the non-linear-inertial properties of devices for recording (analog-to-digital conversion) of signals is considered. The method includes a building of a model of a digitizing device in the form of a nonlinear recursive filter of a limited order (second or third). Two or four non-linear functions in such a model are proposed to be considered as characteristics of the non- linearity of the device. The influence of these characteristics on different parts of the transient response of the device is indicated. For the selected example (digital oscilloscope), it is shown that the nonlinearity of the oscilloscope quantizing unit itself has an unsystematic character, but is small against the background of relatively smooth distortions in the analog path of the oscilloscope.