1. A system for computing a parameter value for a segment of a cardiac-related signal, the system comprising: a computer circuit configured and arranged to identify at least one cardiac cycle within said segment, identify at least one feature point within the at least one cardiac cycle by decomposing said cardiac-related signal into subcomponents, identifying subcomponents of the cardiac-related signal associated with a signal wave containing the at least one feature point, and combining said identified subcomponents to construct an emphasis signal, and evaluating the emphasis signal to identify the at least one feature point, for the at least one identified feature point, compute an estimate of at least one of signal energy and noise energy for a cardiac cycle subsegment containing the at least one identified feature point, and determine a validity characteristic of the at least one feature point based upon the estimate, and compute a parameter value based upon the determined validity characteristics of the at least one feature point.