An apparatus for detecting the position (x) of an at least partly magnetically supported object in the form of an at least partly magnetically supported rotor, in particular an at least partly magnetically supported rotor of a vacuum pump, preferably a turbomolecular pump, said apparatus comprising a contactless sensor system and a digital control and/or evaluation device which is associated therewith and which works at a control frequency (f c), - wherein the control and/or evaluation device comprises means for generating a periodic electrical excitation signal (U e) having an excitation frequency (f e) which is defined by the following relationship: f e = M ⋅ f c, where M is a natural number >1, - wherein the contactless sensor system is designed to modulate the excitation signal (U e) in dependence on the position (x) of the rotor and provides a correspondingly modulated analog sensor signal (U sen) as an output signal, - wherein the control and/or evaluation device comprises means for an A/D conversion of the modulated analog sensor signal (U sen) into a digital sensor signal, the modulated analog sensor signal (U sen) being sampled by said means for an A/D conversion at a sampling frequency f s which is asynchronous with respect to the excitation frequency (f e) and to which the following relationship applies: f s ≠ f e / N, where N is a further natural number which is independent of M, - wherein the control and/or evaluation device comprises calculation means working at the control frequency (f c) for calculating the position (x) of the rotor on the basis of the digital sensor signal provided by the means for an A/D conversion, and - wherein the modulated analog sensor signal (U sen) is sampled by the means for an A/D conversion at an asynchronous sampling frequency f s which is defined by the following relationship: f s = 2 M 2 M ± 1 ⋅ f e, where M is again the natural number >1 and f e is the excitation frequency of the periodic electrical excitation signal. - wherein the control and/or evaluation device comprises means for generating a periodic electrical excitation signal (U e) having an excitation frequency (f e) which is defined by the following relationship: f e = M ⋅ f c, where M is a natural number >1, - wherein the contactless sensor system is designed to modulate the excitation signal (U e) in dependence on the position (x) of the rotor and provides a correspondingly modulated analog sensor signal (U sen) as an output signal, - wherein the control and/or evaluation device comprises means for an A/D conversion of the modulated analog sensor signal (U sen) into a digital sensor signal, the modulated analog sensor signal (U sen) being sampled by said means for an A/D conversion at a sampling frequency f s which is asynchronous with respect to the excitation frequency (f e) and to which the following relationship applies: f s ≠ f e / N, where N is a further natural number which is independent of M, - wherein the control and/or evaluation device comprises calculation means working at the control frequency (f c) for calculating the position (x) of the rotor on the basis of the digital sensor signal provided by the means for an A/D conversion, and - wherein the modulated analog sensor signal (U sen) is sampled by the means for an A/D conversion at an asynchronous sampling frequency f s which is defined by the following relationship: f s = 2 M 2 M ± 1 ⋅ f e, where M is again the natural number >1 and f e is the excitation frequency of the periodic electrical excitation signal.