Path metric normalization in calculating trellis-based algorithms is improved by normalizing the path metric with an average value (rather than a maximum or a minimum) of the path metrics. Using an average rather than a maximum or a minimum provides various advantages without adversely affecting the execution of the trellis-based algorithm. Due to the relatively faster computation time available when an average is computed, average value normalization can be applied every cycle, because its critical path is less than that of the ACS unit.