Second order LMS tap update algorithm with high tracking capability

摘要

The system and method of the present invention, according to one embodiment, employs an adaptive finite impulse response filter having a second order Least Mean Square (LMS) architecture. The filter comprises a plurality of signal feedback loops coupled in parallel, each feedback loop having a correlation multiplier, a loop filter and an integrator coupled in series. Each feedback loop is configured to generate a variable tap coefficient signal. Each loop filter is configured to generate a signal corresponding to the sum of a signal received by the loop filter and the integral of the signal received by the loop filter. The output of each loop filter is provided to an integrator which in turn provides the variable tap coefficient. The filter is configured to sum the products of the tap coefficient signals with delayed versions of the input signal in a tap delay line so as to generate the output signal of the filter. An error signal is genrated that corresponds to the difference between the output signal of the filter and a reference signal. In accordance with another embodiment of the invention, the tap signals are linearly time-varying and the error signal converges to zero.