Robust adaptive equalizer

A communication receiver system including:

• an adaptive equalizer circuit coupled to a signal input source for applying filtered signal values to the output of said equalizer circuit;
• a slicer circuit coupled to the output of said equalizer for detecting transitions in said filtered signal values and for applying corresponding sliced output signal values to the output of said slicer circuit;
• an adder circuit having a first input coupled to said output of said equalizer circuit and having a second input coupled to said output of said slicer circuit for determining a magnitude of the difference between said filtered signal values and a corresponding one of said sliced output signal values and for applying said difference to the output of said adder circuit;
• a threshold value source for providing a threshold value at an output;
• a comparator circuit having a first input coupled to said output of said adder circuit and having a second input coupled to said output of said threshold value source for comparing said difference to said threshold value and for applying a comparison signal to the output of said comparison circuit;
• a divergence minimization value source for providing a divergence minimization value at an output;
• and
• a multiplexor having a selection input coupled to said output of said comparison circuit and having a first input coupled to said output of said adder circuit and having a second input coupled to said output of said divergence minimization value source wherein said multiplexor is operable to apply said difference to said equalizer circuit in response to a first comparison signal applied to said selection input and is operable to apply said divergence minimization value to said equalizer circuit in response to a second signal applied to said selection input.

A method for equalizer adaptation in a communication receiver including the steps of:

• applying sampled signal values received by said receiver to an equalizer circuit to generate filtered signal values;
• applying said filtered signal values to a slicer circuit to generate estimated values of data received by said receiver;
• applying said filtered signal values and said estimated values to an adder circuit to determine a magnitude of the difference between each of said filtered signal values and a corresponding one of said estimated values;
• comparing said difference to a predetermined threshold value to generate a comparison signal;
• and
• applying said difference to said equalizer circuit in response to a first comparison signal value and applying a divergence minimization value to said equalizer circuit in response to a second signal value.