1. A method for identifying the source of crosstalk disturbance in a subscriber loop comprising the steps of: measuring the power spectral density of the noise present on a subscriber loop; correlating the power spectral density for said subscriber loop with a predetermined set of power spectral densities for a group of possible crosstalk disturbers; and, selecting the crosstalk disturber having the most closely correlated power spectral density; and, refining the selection of the crosstalk disturber using a matching pursuit (MP) algorithm.