Abstract: A technique for training an equalizer of an ADSL Annex C transceiver is provided. The technique defines the points in the transmission sequence at which equalizer training should take place, and what symbols comprising the transmission should be used for training. The technique avoids the effect of strong TCM-ISDN cross-talk noise. The equalizer is trained so as to achieve optimal communication channel performance. During the TEQ training phase, the cyclic prefix is not introduced. The TEQ is trained only on FEXT symbols except the FEXT symbols adjacent to NEXT symbols. In the early phase of FEQ training, the cyclic prefix is not introduced. The FEQ is trained on FEXT symbols only except the FEXT symbols adjacent to NEXT symbols. During a late training phase after the cyclic prefix is introduced, the training of the FEQ is continued by using signals received on all FEXT symbols only.

Abstract: A detector provides outputs that are compared to threshold values to determine a valid phase change. Additional discrimination logic may be added to speed the detection process and reduce false detections. Identified patterns relating to NEXT/FEXT frame boundaries allow for NEXT/FEXT frame alignment. Identified patterns for NEXT/FEXT frames in a hyperframe allow for hyperframe alignment.