Loop certification and measurement for ADSL

Abstract

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 the line. In the preferred embodiment, a transmitter applies a known test signal waveform to the transmission line. The test signal corresponds to a desired one of several available xDSL services. At the receiving end of the line, the output signal from the line is sampled, to capture a digitized sample waveform for the received signal. A computer processes the captured waveform to determine eigenvalues characterizing the transfer function of the line with respect to the one service. If the eignevalues for the line bear predetermined relationships to threshold values, indicating acceptable line transfer function for the desired xDSL service, then the invention certifies the tested line for use on that service.

Dependencies are inferred from the claim text.