Patent ID: 6970896

Claim:
A filter adaptation unit suitable for producing a set of filter coefficients indicative of a transfer function of a system in a given state, said filter adaptation unit comprising: a) a first input for receiving a sequence of samples of a first signal; b) a second input for receiving a sequence of samples of a second signal, the second signal including a certain component which is correlated to the first signal; c) a coefficient generation unit operatively coupled to said first input and said second input, said coefficient generation unit being operative for generating: i. a first set of filter coefficients on the basis of first subsets of the sequences of samples of the first signal and the second signal, the first set of filter coefficients being such that when the first set of filter coefficients is applied by an adaptive filter on the first signal, a first estimate of the certain component in the second signal is generated, the certain component being correlated to the first signal; ii. a second set of filter coefficients on the basis of second subsets of the sequences of samples of the first signal and the second signal, at least some samples in the second subsets being subsequent to the samples in corresponding first subsets, the second set of filter coefficients being such that when the first set of filter coefficients is applied by an adaptive filter on the first signal, a second estimate of the certain component in the second signal is generated, the certain component being correlated to the first signal; d) an error characterization unit operative for: i. processing the first signal and the second signal on the basis of the first set of filter coefficients to generate a first set of error characterization data elements associated to the first set of filter coefficients; ii. processing the first signal and the second signal on the basis of the second set of filter coefficients to generate a second set of error characterization data elements associated to the second set of filter coefficients; e) a selection unit operative for: i. detecting a change of state at least in part of the basis of: (a) the first and second sets of filter coefficients; and (b) the second set of error characterization data elements; ii. selecting the second set of filter coefficients when a change of state is detected in i.; iii. selecting either one of the first set of filter coefficients and the second set of filter coefficients, at least in part, on the basis of the first and second sets of error characterization data elements when no change of state is detected in i.; f) an output for releasing a signal indicative of the set of filter coefficients selected by the selection unit.