Pipelined adaptive IIR filter

A pipelined adaptive infinite impulse response (PAIIR) filter including an adaptive section and a non-adaptive section, the PAIIR filter being responsive to first and second input signals comprising:

• the adaptive section including:
• delay means for re-timing a first polynomial value signal, the second input signal, an error signal, and a second polynomial value signal;
• and
• first polynomial signal generating means for performing relaxed look-ahead processing on the second input signal in the adaptive section, the first polynomial signal generating means being responsive to the re-timed error signal so as to generate and adaptively update a first set of weight signals corresponding to first polynomial weights and so as to generate the first polynomial value signal therefrom;
• second polynomial signal generating means for performing relaxed look-ahead processing on the first input signal in the adaptive section, the second polynomial signal generating means being responsive to the re-timed error signal so as to generate and adaptively update a second set of weight signals corresponding to second polynomial weights and so as to generate the second polynomial value signal therefrom;
• and
• adding means responsive to the re-timed second input signal to generate the error signal therefrom, the adding means including:
• a first adder being responsive to the re-timed first and second polynomial value signals so as to generate a feedback signal therefrom;
• and
• a second adder being responsive to the re-timed second input signal and the feedback signal so as to generate the error signal therefrom;
• and
• the non-adaptive section including:
• output filter means for performing scattered look-ahead processing on the re-timed second polynomial value signal and the first set of weight signals in the non-adaptive section so as to generate an expected output signal.

A pipelined adaptive infinite impulse response (PAIIR) filter being responsive to first and second input signals comprising:

• delay means for re-timing a first polynomial value signal, a second polynomial value signal, the second input signal, and an error signal;
• first polynomial signal generating means for performing relaxed look-ahead processing on the second input signal, the first polynomial signal generating means being responsive to the re-timed error signal so as to generate and adaptively update a first set of weight signals corresponding to first polynomial weights and so as to generate the first polynomial value signal therefrom;
• second polynomial signal generating means for performing relaxed look-ahead processing on the first input signal, the second polynomial signal generating means being responsive to the re-timed error signal so as to generate and adaptively update a second set of weight signals corresponding to second polynomial weights and so as to generate the second polynomial value signal therefrom;
• first adding means being responsive to the re-timed first and second polynomial value signals so as to generate a feedback signal therefrom;
• second adding means being responsive to the re-timed second input signal and the feedback signal so as to generate the error signal therefrom;
• and
• output filter means for performing scattered look-ahead processing on the re-timed second polynomial value signal and the first set of weight signals so as to generate an expected output signal.

A system including a plant having a plant input signal and a plant output signal, the system being responsive to a first input signal including the plant input signal, and being responsive to a second input signal including the plant output signal, the system comprising:

• re-timing delay means for re-timing a numerator value signal, a denominator value signal, the second input signal, and an error signal;
• feedback signal generating means responsive to the re-timed numerator and denominator value signals so as to generate a feedback signal therefrom;
• error signal generating means responsive to the re-timed second input signal and the feedback signal so as to generate the error signal therefrom;
• numerator polynomial signal generating means for performing relaxed look-ahead processing on the first input signal and being responsive to the re-timed error signal so as to generate and adaptively update a set of numerator weight signals corresponding to numerator polynomial weights and so as to generate the numerator value signal from the first input signal and the set of numerator weight signals;
• denominator polynomial signal generating means for performing relaxed look-ahead processing on the re-timed second input signal and being responsive to the re-timed error signal so as to generate and adaptively update a set of denominator weight signals corresponding to denominator polynomial weights and so as to generate the denominator value signal from the second input signal and the set of denominator weight signals;
• and
• output filter means for performing scattered look-ahead processing on the re-timed numerator value signal and the set of denominator weight signals so as to generate an expected output signal.

A method for processing first and second input signals using a pipelined adaptive infinite impulse response (PAIIR) filter comprising the steps of:

• (a) initializing first and second sets of weight signals;
• (b) receiving first and second input signals;
• (c) performing relaxed look-ahead processing on the first and second input signals and the first and second sets of weight signals to generate first and second polynomial value signals therefrom using relaxed look-ahead processing means;
• (d) generating a feedback signal from the first and second polynomial value signals using feedback signal generating means;
• (e) generating an error signal from the second input signal and the feedback signal using error signal generating means;
• and
• (f) adaptively generating successive first and second sets of weight signals from the first and second input signals, the sets of first and second weight signals and the error signal using weight generating means;
• and
• (g) repeating steps (b)-(f) using the successive first and second sets of weight signals as first and second sets of weight signals, respectively, to adaptively update the weight signals to adaptively process the first and second input signals.