Efficient tapped delay line equalizer methods and apparatus

Circuitry for equalizing an input signal, said circuitry comprising:

• a multiplexer operable to receive a first set of feedforward taps with a plurality of data inputs, wherein respective ones of feedforward taps are coupled to respective ones of the plurality of data inputs;
• feedforward filter circuitry operable to receive said input signal, wherein said feedforward filter circuitry is coupled to an output of the multiplexer;
• feedback filter circuitry in communication with said feedforward filter circuitry, wherein said feedback filter circuitry is configured to select a first set of feedback taps;
• and
• control circuitry in communication with said feedforward filter circuitry and said feedback filter circuitry, said control circuitry comprising:
• selector circuitry configured to generate a control signal received at a control input of the multiplexer, based on which one of the plurality of data inputs of the multiplexer is coupled to the output of the multiplexer to filter said input signal, wherein the coupling generates a second set of feedforward taps;
• and
• feedback tap addition circuitry in communication with said feedback filter circuitry, wherein said feedback tap addition circuitry is configured to generate a second set of feedback taps by adding, in response to the coupling, a compensating set of feedback taps to said first set of feedback taps to filter said input signal.

Circuitry for equalizing an input signal, said circuitry comprising:

• multiplexer means for receiving a first set of feedforward taps with a plurality of data inputs, wherein respective ones of feedforward taps are coupled to respective ones of the plurality of data inputs;
• feedforward filter means for receiving said input signal, wherein said feedforward filter means is coupled to an output of the multiplexer means;
• feedback filter means for receiving a signal responsive to said input signal, wherein said feedback filter means is in communication with said feedforward filter means, and wherein said feedback filter means is configured to select a first set of feedback taps;
• and
• control means for controlling feedforward taps of said multiplexer means and feedback taps of said feedback filter means, wherein said control means is in communication with said multiplexer means and said feedback filter means, said control means comprising:
• selector means for generating a control signal received at a control input of the multiplexer, based on which one of the plurality of data inputs of the multiplexer is coupled to the output of the multiplexer to filter said input signal, wherein the coupling generates a second set of feedforward taps, wherein:
• said selector means is in communication with said feedforward filter means;
• and
• feedback tap addition means for adding a set of feedback taps to said first set of feedback taps to generate, in response to the coupling, a compensating second set of feedback taps to filter said input signal, wherein said feedback tap addition means is in communication with said feedback filter means.