A method for analyzing the condition of a machine having a rotating shaft, including: generating an analog electric measurement signal (SEA) dependent on mechanical vibrations emanating from rotation of the shaft; sampling the analog measurement signal at a sampling frequency (fS) so as to generate a digital measurement data signal (SMD) in response to the received analog measurement data; performing a decimation of the digital measurement data signal (SMD) so as to achieve a digital signal (SRED) having a reduced sampling frequency (fSR1, fSR2); wherein the decimation includes the step of controlling the reduced sampling frequency (fSR1, fSR2) such that the number of sample values per revolution of the shaft (8) is kept at a substantially constant value; and performing a condition analysis function (F1, F2, Fn) for analyzing the condition of the machine dependent on the digital signal (SRED) having a reduced sampling frequency (fSR1, fSR2).