Adaptive nonrecursive digital filter and method for forming filter coefficients therefor

A method for forming filter coefficients for an adaptive nonrecursive digital filter having a signal processing device operating under program control for generating an output signal from an input signal connected with N controllable filter coefficients for generating control signals for controlling the filter coefficients in combination with a reference signal, in accordance with the least mean square error, where N and B positive integers, which method comprises:

• a) continuously storing sampled values of the input signal and of the reference signal in memory, each at discrete sampling times and each for a certain number of sampling times;
• b) assigning N+B-1 successive stored sampled values of the input signal to B groups partly overlapping one another, each of the groups including N sampled values;
• c) forming a sum of all of the sampled values of the input signal belonging to a certain group, each sampled value being weighted with one of the filter coefficients for producing a further output signal;
• d) multiplying the stored sampled values of the input signals multiple times cyclically and in groups with an error signal being weighted by a coefficient, and subsequently integrating the samples, producing the control signals for the coefficients;
• e) cyclically weighting in groups, the sum of all of the sampled values of the input signal belonging to the applicable group with one of the filter coefficients being formed;
• and
• f) subtracting this sum from one of B stored sampled values of the reference signal, producing the error signal.