A method, and apparatus for carrying it out, for processing pulses derived from a radiation detector, those pulses having already been resolved by a pulse-height analyzer into channels having respective addresses indicative of their respective heights. The method includes steps of receiving a plurality of channel-address values from the pulse-height analyzer, averaging over a window selected ones of the channel-address values to obtain an average channel address for the selected channel-address values, and using the average channel address to increment the content of a spectrum channel. Speed and accuracy of execution of the method may be optimized if a criterion for selecting channel-address values for averaging is made variable so as to permit recycling of the channel addresses and so as to avoid counting losses.