Patent ID: 6934655

Claim:
A method for utilizing a modem to perform time domain reflectometry on a communication channel comprising: connecting a modem to a communication channel; generating a maximal length sequence signal utilizing the modem; transmitting the sequence signal over the communication channel; receiving a reflection signal from the communication channel in response to the transmitting of the sequence signal; correlating the reflection signal within the modem with the sequence signal to generate a correlated signal; retrieving a template signal; aligning the template signal and the correlated signal to determine a point of alignment; subtracting the template signal from the correlated signal to remove near-end echo from the correlated signal; measuring a time interval between the point of alignment and a subsequent peak in the correlated signal; multiplying the time interval by a rate of propagation of the sequence signal through the communication channel to obtain distance information regarding a line anomaly; performing a circular rotation of the sequence signal to create a rotated sequence signal; transmitting the rotated sequence signal over the communication channel; receiving a rotated reflection signal; correlating the rotated reflection signal with the rotated sequence signal to create a rotated correlated signal; aligning the rotated correlated signal with the correlated signal; and adding the rotated correlated signal to the correlated signal to reduce or remove correlation artifacts on the correlated signal.