Detecting nonlinearity in a cable plant and determining a cable length to a source of the nonlinearity

摘要

An apparatus and a method for detecting a nonlinearity in a cable plant and for determining cable length to a source of the nonlinearity are disclosed. Upstream signal peaks are detected by averaging upstream signal waveforms. The upstream signal peaks are generated at the source of the nonlinearity from naturally occurring downstream signal peaks propagating in the cable plant. The downstream signal peaks occur due to constructive superposition of the downstream channel signals. Acquisition of the upstream signal waveforms is triggered by the downstream signal peaks. The cable length to the source of nonlinearity is determined from a time delay between the downstream signal peaks and the upstream signal peaks.