Methods of processing a digital signal obtained from a four-electrode transverse position sensor of ion bunches during acceleration in a synchrotron are discussed. A technique has been developed for reconstructing the amplitude spectrum of betatron oscillations of an ion bunch in the case of a sensor displacement relative to the initial position determined during calibration. The results obtained are used to reconstruct the amplitude spectrum of betatron oscillations of a bunch after injection of xenon ions into the JINR booster synchrotron.