A method for analyzing the condition of a machine having a rotating shaft, includes:receiving a digital input signal (I) having a first plurality (ILENGTH) of sample values, the digital input signal (I) representing mechanical vibrations emanating from rotating the shaft so far as to cause occurrence of a vibration having a period of repetition (TR); dividing the received digital input signal (I) into a first signal portion (2070) and a second signal portion; generating a digital output signal (O) having a second plurality (OLENGTH) of samples, the second plurality (OLENGTH) being a positive integer and lower than the first plurality (ILENGTH); the digital output signal (O) being generated in response to the first signal portion (2070) and the second signal portion.