A very powerful generalized two-dimensional correlation method applicable to various types of spectroscopy involving signals dependent on various physical variables (e.g., time) was recently developed and reported. In order to obtain an easy computational procedure, the effect of the practical limitation of the data along the time axis to N is considered. This information gives rise to a new formula for the disrelation spectrum. This modified disrelation spectrum is shown to still be useful in the differentiation of overlapping peaks, even when N is small.