SINGLE ENDED LINE PROBING IN DSL SYSTEM

摘要

SELP techniques that provide an accurate estimate of the length of a transmission medium (e.g., subscriber loop in a DSL system) are disclosed. A probe signal is transmitted over the transmission medium at one or more frequencies. A reflected version of the probe signal is then received. Transmission medium impedance is determined based on the ratio of the reflected version of the probe signal and the transmitted probe signal. An estimate of transmission medium length is determined by comparing its impedance to a plurality of predetermined impedances, each of which is associated with a transmission medium having known length. Thus, the length of the systems transmission medium is identified. The transmission medium impedance can also be used to identify the presence of load coils and short circuits in the transmission medium.