A receiver in a radio system, the receiver comprising means for receiving a signal, an analogue-to-digital converter for providing signal samples from the received signal. The receiver comprises means for selecting a set of signal samples, means for forming a statistical function value on the basis of the selected signal sample values, means for forming a threshold value on the basis of the statistical function value and a preset threshold parameter, means for dividing the samples between a set within the statistical distribution and a set outside the distribution by using the threshold value as a limit, and means for repeating said statistical function value formation by using the set in accordance with the distribution, said threshold value formation and said division of samples into said sets if the termination condition for repetition is not fulfilled.