Adaptive equalization with group delay

An apparatus for performing adaptive equalization comprising:

• a receiver for receiving a signal originating from a communication channel;
• a filter having adjustable tap weights for filtering the received signal to produce a filtered signal;
• a clock recovery circuit configured to produce a clock signal from the filtered signal;
• and
• a coefficient unit for supplying the adjustable tap weights, where the coefficient unit is configured to update the adjustable tap weights to reduce a measure of error in the filtered signal and to reduce a squared difference between a group delay associated with the filter and a target group delay, and wherein adaptation of the adjustable tap weights by the coefficient unit to reduce squared difference between the group delay associated with the filter and the target group delay group delay associated with the filter reduces undesired interaction between the filter and the clock recovery circuit.

A method for performing adaptive equalization, comprising:

• receiving a signal from a communication channel;
• filtering the received signal utilizing a filter having adjustable tap weights to produce a filtered signal;
• and
• adaptively updating the adjustable tap weights to new values, where updating includes adding a first value based on a measure of error in the filtered signal and adding a second value based on a difference between a group delay of the filter and a target group delay, and wherein the second value is a first quantity multiplied by the difference between an index of each adjustable tap weight and the target group delay, the first quantity being a summation of each of the adjustable tap weights multiplied by the difference between an index of the adjustable tap weight and the target group delay.