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. <EOS>