Power-efficient nonlinear equalizers and methods

An equalization method that converts a receive signal into a sequence of symbol decisions, the method comprising:

• using a linear filter on the receive signal to obtain a filtered signal for deriving a first sequence of equalized signal samples;
• deriving a tentative sequence of symbol decisions from the first sequence of equalized signal samples;
• using a nonlinear filter that, when enabled, operates on the receive signal to derive a second sequence of equalized signal samples;
• using a decision element that, when enabled, derives replacement symbol decisions from the second sequence of equalized signal samples;
• calculating an equalization error for each symbol decision in the tentative sequence;
• and
• selectively enabling the nonlinear filter and the decision element to obtain a replacement symbol decision for each symbol decision in the tentative sequence having an equalization error greater than a predetermined value.

A semiconductor intellectual property core that generates circuitry for an equalizer, wherein the equalizer comprises:

• a linear filter that operates on a receive signal to obtain a filtered signal as part of deriving a first sequence of equalized signal samples from the receive signal;
• a first decision element that derives a tentative sequence of symbol decisions from the first sequence of equalized signal samples;
• a nonlinear filter that, when enabled, operates on the receive signal as part of deriving a second sequence of equalized signal samples from the receive signal;
• a second decision element that, when enabled, derives replacement symbol decisions from the second sequence of equalized signal samples;
• a subtraction element that calculates an equalization error for each symbol decision in the tentative sequence;
• and
• a controller that selectively enables the nonlinear filter and the second decision element to obtain a replacement symbol decision for each symbol decision in the tentative sequence having an equalization error greater than a predetermined value.