Possibilities for Obtaining the Derivative of a Received Signal Using Computer-Driven Second Order Oscillators

As it is known, a first step in modeling dynamic phenomena consists in measuring with higher accuracy some physical quantities corresponding to the dynamic system. However, for suddenly-emerging phenomena ,the data acquisition can’t be restricted at sampling procedures for a received signal (corresponding to a certain physical quantity). A significant quantity is represented by the derivative (the slope) of the received signals, because all dynamical models must take it into consideration. Usually the derivative of a received signal is obtained by filtering the received signal and by dividing the difference between the filtered values of the signal at two different moments of time at the time difference between these time moments. Many times these filtering and sampling devices consists of low-pass filters represented by asymptotically stable systems, sometimes an integration of the filter output over a certain time interval being added. However, such a structure is very sensitive at random variations of the integration period, and so it is recommended the signal which is integrated to be approximately equal to zero at the end of the integration period. It will be shown that the simplest structure with such properties is represented by an oscillating second order computer-driven system working on a time period.