Reactive sensors typically exhibit nonlinear response to the combination of an excitational signal (e.g., sinusoidally oscillating signal) and a physical parameter under measure (e.g., position of magnetic core member). Such sensors are typically sensitive to temperature variation. Systems and methods are disclosed for compensating for the nonlinear and/or temperature dependant behavior of reactive sensors and for calibrating the post-compensation output signals relative to known samples of the physical parameter under measure (e.g., position). One class of embodiments comprises a housing containing at least part of a reactive sensor, a monolithic integrated circuit and a timing reference (e.g., an oscillator crystal). The integrated circuit includes a waveform generator for generating a sensor exciting signal, a detector for detecting the response of the sensor to the combination of the exciting signal and the under-measure physical parameter, a temperature compensating unit and a Pade' Approximant based, nonlinearity compensating unit. The temperature compensating unit and the Pade' Approximant nonlinearity compensating unit are tuned by use of digitally programmed coefficients. The coefficients calibrate the final output as well as compensating for nonlinearity and temperature sensitivity. A highly accurate measurement of the under-measure physical parameter is made possible even though each of the sensor and compensating circuitry may be relatively simple, compact, and low in cost.