Apparatus and method for measuring loop insertion loss single-endedly

摘要

The system and method of determining insertion loss of a telephone line under test (LUT) determines a first insertion loss as a function of plurality of different equivalent circuit values of the LUT determined at a plurality of different frequencies of a first set of discrete frequencies. A running standard deviation (rSTD) of a predicted length d of the LUT at each frequency of a second set of discrete frequencies is determined from the predicted lengths d of the LUT at and below said frequency. A second insertion loss is determined based on the pair of adjacent discrete frequencies of the second set of discrete frequencies that have the largest difference between their rSTDs. Based on a comparison of the first and second insertion losses to an expected insertion loss, one of these insertion losses is deemed to be the actual insertion loss of the LUT.