METHOD AND APPARATUS FOR ADJUSTING RECEIVER VOLTAGE THRESHOLD AND PHASE SAMPLING POINT USING FEC COUNTS

Methods and apparatus are provided for adjusting slicing parameters, such as a voltage threshold and a phase sampling point, used in recovering 1's and 0's from a signal so as to reduce a bit error rate (BER) of the signal. The BER is modelled as a second order polynomial of the slicing parameters. The BER is repeatedly determined from a Forward Error Correction corrected bits counter. For each BER measurement the model is updated, using for example a recursive least squares fit. New values of the slicing parameters are then determined by carrying out an iteration of an optimization, such as a Levenberg-Marquardt optimization, using the model. The new values of the slicing parameters are passed to a Clock and Data Recovery module. Various conditions are checked before updating the model or determining the new values of the slicing parameters, such as changes in signal power or high BERs which exceed the error correction capabilities of the forward error correction.