Non-invasive diagnostic transmission line testing

摘要

A probing signal transmitted on a twisted pair telephone line in a DSL system is reflected and received at a DSL device. An estimate of one of a DSL data transmission signal or DSL synch symbol transmission signal is removed from the received probing signal to recover the reflected probing signal. The recovered reflected probing signal is processed to determine characteristics information of the twisted pair telephone line.

主权项

1. A method comprising:
transmitting a probing signal on the twisted pair telephone line from a Digital Subscriber Line (DSL) device coupled to the line, wherein the probing signal is transmitted in a frequency used for upstream data transmission or downstream data transmission in a DSL system that employs frequency-division duplexing of upstream and downstream data transmission, in one of an upstream direction from a customer premises location or a downstream direction from a central office location, during one of a DSL data transmission period or DSL sync symbol transmission period; receiving the probing signal reflected on the twisted pair telephone line at the DSL device; removing an estimate of one of a DSL data transmission signal or DSL synch symbol transmission signal from the received probing signal to recover the reflected probing signal; and processing the recovered reflected probing signal to determine characteristics information of the twisted pair telephone line.