Patent ID: 6694017
Filing Date: 2004-02-17
Classification: H04B

Abstract:
An automatic gain control method for use in a communication system having a bi-directional two-wire line, a four-wire line with an incoming path carrying an incoming signal and an outgoing path carrying an outgoing signal, and an interface circuit electrically coupling the two-wire line to the four-wire line, comprising the steps of:(a) measuring respective levels of the incoming signal on the incoming path and an echo of the incoming signal reflected by the interface circuit onto the outgoing path, thereby determining an echo return loss; (b) calculating a first gain from the echo return loss; and (c) amplifying the incoming signal by the first gain before transmission through the interface circuit to the two-wire line, thereby compensating for the echo return loss, so that the incoming signal reaching the two-wire line has a desired level.