Patent ID: 7155174
Filing Date: 2006-12-26
Classification: H03D,H03J

Abstract:
1. In a communication back-end device adapted to operate with a front-end device, the front-end device receiving a downstream signal and transmitting an upstream signal, the front-end device mixing the downstream signal with a free-running LO signal including a frequency offset (FO), thereby producing an initial downstream signal including the FO, a method of compensating for the FO, comprising: (a) receiving the initial downstream signal including the undesired FO, wherein the initial downstream signal includes a master timing signal; (b) deriving from a corrected downstream signal an estimate of the FO included in the initial downstream signal based on a reference frequency derived from the master timing signal and an estimator signal indicative of a portion of the undesired FO included in the corrected downstream signal; (c) removing the estimated FO from the initial downstream signal, thereby producing the corrected downstream signal; (d) frequency pre-correcting an initial upstream signal with the estimated FO, thereby generating a pre-corrected upstream signal; and (e) providing the pre-corrected upstream signal to the front-end device, whereby the front-end device mixes the frequency pre-corrected upstream signal with the free-running LO signal to produce the upstream signal such that the upstream signal is free of the undesired FO to the extent the estimated FO represents the undesired FO.