Patent ID: 6687306
Filing Date: 2004-02-03
Classification: H04B,H04L

Abstract:
For a signal processing application, a method of adjusting a signal representing a modem constellation, the signal transmitted through a telecommunication channel between source and destination modems and subjected to at least two of a plurality of line encoding algorithms, the method comprising the steps of:(a) detecting the two line encoding algorithms based on a set of test levels included in the signal to identify encoding conversion compensation values, wherein the source modem transmits the signal with a constellation based on one line encoding algorithm and the destination modem transmits to the source modem with constellation based on an other line encoding algorithm, wherein each of the encoding algorithms encodes one of the set of test levels to generate a substantially equivalent value, and step (a) comprises the step of normalizing, based on the one of the test levels, one or more remaining test levels received by at least one of the source and destination modems for comparison with a decision metric; (b) detecting a superimposed information channel in the signal to identify channel compensation values; (c) detecting line attenuation of the signal to identify gain compensation values; (d) compensating the test levels of the signal based on at least one of i) the encoding conversion compensation values and ii) the gain compensation values; and (e) adjusting the constellation at the destination modem in accordance with the encoding conversion, channel, and gain compensation values.