Abstract: A process masks non-relevant measured values in an unbalance signal consisting of a large number of individual measured values and a circuit arrangement determines the unbalance of a rotatable object in at least one measuring plane with at least one oscillation transducer and one angle position pick-up for processing the unbalance measuring signal. A display device displays the unbalance in terms of position and magnitude and/or a processing device further processes the unbalance, in order for a system based on fuzzy logic to take into account any unexpected interferences during the formation of the unbalance measured value. In the case of greatly deviating individual measured values, a system based on fuzzy logic which recognizes the course of the unbalance measuring signal that can be roughly expected masks these values as non-relevant.