The present invention provides for adaptive filters that have improved computational
and memory bandwidth proprieties. When applied to telecommunication applications,
the present invention additionally provides for improved methods and systems of
canceling echoes. In one embodiment of the adaptive filter of the present invention,
a filter, preferably an adaptive finite impulse response (FIR) filter, of an appropriate
length, N, is chosen. Once the filter is chosen, convergence is achieved and the
filter is converted to an infinite impulse response (IIR) filter. In the course
of operation, data is received from an input source and used to adapt the zeroes
of the IIR filter using the least means square (LMS) approach, keeping the poles
fixed. The adaptation process generates a set of converged filter coefficients
that are then applied to the input signal to create a modified signal used to filter
the data. The novel adaptive filter method and system presented herein can be used
to improve the calculation of the echo impulse response by, among other things,
reducing the computational complexity and memory requirements of the coefficient
calculation conducted within the adaptive filter.