Digital adaptive finite impulse response filter with large number of coefficients
First Claim
1. An adaptive multi-loop filter system for receiving (i) a signal input to a system to be characterized and (ii) a signal output from said system to be characterized for producing an estimated replica signal of said signal output, said filter system comprising:
- at least first and second filter units connected in cascade, each of said filter units comprising (i) receiving means receiving signal samples related to said signal input, each said receiving means includes first storage means having an input and an output, the output of said first storage means in said first filter unit being applied to the input of said first storage means in said second filter unit, (ii) characterizing means for characterizing the estimated partial impulse response of said system, the output of said first storage means also being applied to an input of said characterizing means, and (iii) means responsive to said receiving means and said characterizing means for producing an estimated partial replica signal,means for combining said estimated partial replica signals from said first and second filter units to form said estimated replica signal of said signal output,means for producing an error signal representative of the difference between the signal output of the system to be characterized and said estimated replica signal, and means for updating the value of said partial estimated impulse response signals as a function of said error signal and said signal samples related to said signal inputs.
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Abstract
A digital adaptive finite impulse response (AFIR) filter having a large number of coefficients is composed of two or more separate filter units. The first filter unit computes response samples ho -Hn+1 in response to input signal samples to provide a partial estimated response during each sampling period. After the signal samples are fully processed by the first unit, they are transferred to a second filter unit which produces response samples hn+2 -hp+1 in response thereto to provide a second partial response. The sum of the two partial responses is computed to provide the total estimated system response. The two independent filter units thus act simultaneously to provide twice as many coefficients as prior art AFIR filters in the same amount of time.
68 Citations
14 Claims
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1. An adaptive multi-loop filter system for receiving (i) a signal input to a system to be characterized and (ii) a signal output from said system to be characterized for producing an estimated replica signal of said signal output, said filter system comprising:
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at least first and second filter units connected in cascade, each of said filter units comprising (i) receiving means receiving signal samples related to said signal input, each said receiving means includes first storage means having an input and an output, the output of said first storage means in said first filter unit being applied to the input of said first storage means in said second filter unit, (ii) characterizing means for characterizing the estimated partial impulse response of said system, the output of said first storage means also being applied to an input of said characterizing means, and (iii) means responsive to said receiving means and said characterizing means for producing an estimated partial replica signal, means for combining said estimated partial replica signals from said first and second filter units to form said estimated replica signal of said signal output, means for producing an error signal representative of the difference between the signal output of the system to be characterized and said estimated replica signal, and means for updating the value of said partial estimated impulse response signals as a function of said error signal and said signal samples related to said signal inputs. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification