The present invention involves a transmission of a known signal over a line intended for a digital subscriber line (xDSL) service, measurement of a resulting waveform received through the line and processing of the received signal to derive a set of eigenvalues characterizing the transfer function of...http://www.google.fr/patents/US6215855?utm_source=gb-gplus-shareBrevet US6215855 - Loop certification and measurement for ADSL
