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US 4,731,834 AGranted
Adaptive filter including signal path compensation
AssigneeAmerican Telephone and Telegraph Company, AT&T Bell Laboratories
InventorsDonald L. Duttweiler, John Hartung
Life of this patent
Estimating the term…
Abstract
Impulse response estimation is improved in an adaptive filter by compensating digital signals incoming to the filter to include a nonlinearity substantially identical to a nonlinearity included in a return signal path to the filter.
Claims8
In combination:
- an adaptive filter having first and second inputs and being adapted to be connected in circuit relationship with a transmission path;
- first means having an input and an output for converting incoming digital signals supplied to said first means input from a first digital code to a second digital code, said digital signals in said second digital code being supplied from said output to said transmission path;
- and
- second means having an input and an output for converting said incoming digital signals supplied to said second means input from said first code to said second code and from said second code to said first code and said second means output being connected in circuit relationship with said first input of said adaptive filter, wherein a nonlinearity substantially identical to a nonlinearity introduced by said first means into signal being supplied by said transmission path to said second input of said adaptive filter is introduced by said second means into signals supplied to said first input of said adaptive filter.
1 more element
In combination:
- an adaptive filter having first and second inputs and being adapted to be connected in circuit relationship with a transmission path;
- first means having an input and an output for converting incoming digital signals supplied to said first means input from a first digital code to a second digital code, digital signals in said second digital code being supplied from said output to said transmission path;
- and
- second means having an input and an output for converting said incoming digital signals supplied to said second means input from said first code to said second code and from said second code to a third digital code and said second means output being connected in circuit relationship to supply said third code signal to said adaptive filter first input, wherein a nonlinearity substantially identical to a nonlinearity introduced into signals supplied from said first measn by said transmission path to said second input of said adaptive filter is introduced into signals supplied by said second means to said first input of said adaptive filter.
1 more element
Dependencies are inferred from the claim text.