2018-04-062018-04-062018-03-06Celik, Ozkan, Chawda, Vinay and O'malley, Marcia K., "Method and device for real-time differentiation of analog and digital signals." Patent US9910411B2. issued 2018-03-06. Retrieved from <a href="https://hdl.handle.net/1911/99798">https://hdl.handle.net/1911/99798</a>.https://hdl.handle.net/1911/99798The controller includes a differentiating engine configured to receive an input signal value (ISV), wherein the ISV corresponds to state information for one selected from a group consisting of a controlled process and a user interface. The differentiating engine is further configured to determine an error between the ISV and an estimated input signal (EIS), estimate a frequency of the IS, select a plurality of pre-determined gains using the frequency, wherein at least one plurality of pre-determined gains is a suction control gain, determine a first estimated derivative of the input signal (EDIS) using the plurality of pre-determined gains and the error, and to output the first EDIS.20engUtility patentUS9910411B2