Cable length estimation circuit using data signal edge rate detection and analog to digital conversion

摘要

A cable length estimation circuit for receiving an input MLT-3 signal provided through an arbitrary length cable and providing a control signal to an equalizer indicating the estimated length of the cable enabling the equalizer to compensate for distortion of the MLT-3 signal resulting from the cable. The cable length estimation circuit includes an edge rate detection circuit for measuring the rate of change in voltage with respect to time during transitions of the MLT-3 signal to provide an indication of cable length. The cable length estimation circuit can also include a digital averaging circuit which provides an average value for signals from the edge rate detection circuit for a desired number of transitions of the MLT-3 signal. The cable length estimation can also include a baseline wander detection circuit which functions so that previous cable length estimations are provided when baseline wander is detected.