Patent Document ID: 20060039458
Application ID: 10919267
Patent Flag: 0

Claim One:
1. A method of adaptive filtering using a fast affine projection adaptive filter, comprising steps of: (a) initializing adaptive filter coefficients of the filter; (b) updating the adaptive filter coefficients by: (i) setting a normalized step size; (ii) determining autocorrelation matrix coefficients of an autocorrelation matrix R N from a reference input signal; (iii) directly determining a projected error vector ε N (n+1) by solving an N-th order positive-definite system of linear equations R N ε (n+1)= e N (n+1) using a backward recursion, followed by a forward recursion, on a known projected error vector ε N (n), where e N (n+1) is a prefixed, one position down shifted version of the current output signal vector e N (n) scaled in accordance with the normalized step size; (iv) updating the adaptive filter coefficients in accordance with coefficients of the projected error vector; and (c) repeating step (b) as required.