A method for analyzing a machine having a rotating shaft includes: generating an electric measurement signal dependent on vibrations emanating from the shaft; sampling the measurement signal at a sampling frequency to generate a digital measurement data signal; performing a decimation of the digital measurement data signal to achieve a digital signal having a reduced sampling frequency, the decimation including controlling the reduced sampling frequency such that the number of sample values per revolution of the shaft is kept at a substantially constant value; receiving the digital signal at an enhancer input; performing a correlation in the enhancer so as to produce an output signal sequence wherein repetitive signals amplitude components are amplified in relation to stochastic signal components; and performing a condition analysis function for analyzing the condition of the machine dependent on the digital signal having a reduced sampling frequency.