Least squares adaptive lattice equalizer

Equalizer apparatus comprising:

• a number of successively coupled lattice stages, each of said stages comprising a selected configuration of adjustable electrical components, the input to the first stage of said successively coupled lattice stages comprising the output of a data transmission channel, each of said lattice stages comprising:
• a first multiplier element for amplifying an input to said first multiplier element by a first multiplier coefficient;
• and
• a lattice section which includes second and third multiplier elements, the lattice sections of all of said lattice stages of said apparatus being coupled in cascade relationship to form a lattice;
• error generating means coupled to said lattice stages for providing a succession of error terms, each of said error terms comprising an accumulation of error quantities, each of said error terms representing the difference between an undistorted training signal, in a sequence of undistorted training signals which are received by said error generating means, and the same training signal after it has traveled through said data transmission channel and been received by said lattice stages;
• component adjust means for iteratively adjusting said electrical components in response to said training signals, said error generating means providing an error term which is within a prespecified limit when said components are iteratively adjusted in response to the final training signal in said sequence, said component adjust means comprising a number of component adjust elements, each of said component adjust elements being coupled to a corresponding lattice section;
• and
• the component adjust element corresponding to a given lattice stage comprising means for performing a series of operations in accordance with a least squares procedure, and in response to one of said training signals, to generate multiplier coefficients for the first, second and third multiplier elements of said given lattice stage.

Equalizer apparatus comprising:

• a number of successively coupled lattice stages, each of said lattice stages comprising a selected configuration of adjustable electrical components, the input to the first lattice stage of said successively coupled lattice stages comprising the output of a data transmission channel;
• means for coupling a given one of the discrete training signals in a sequence of discrete training signals to the first error generating element in a succession of error generating elements, said given training signal being coupled to said first error generating element at the time that said given training signal is coupled to said first lattice stage through said data transmission channel;
• each of said error generating elements having a first and a second input and comprising means for generating an error quantity which represents the difference between its first and second inputs, the first input to a given error generating element comprising the output of one of said lattice stages, the second input to the given error generating element comprising the error quantity generated by the error generating element which immediately precedes the given error generating element in said succession;
• and
• component adjust means coupled to respective components of said lattice stages and receiving each of said error quantities, said component adjust means comprising means for adjusting said respective components to diminish the error quantity of a given one of said error generating elements to within a prespecified error limit.

Equalizer apparatus comprising:

• a number of successively coupled lattice stages, each of said lattice stages comprising a selected configuration of adjustable electrical components, the input to the first lattice stage of said successively coupled lattice stages comprising the output of a data transmission channel;
• means for coupling a given one of the discrete training signals in a sequence of discrete training signals to the first error generating element in a succession of error generating elements, said given training signal being coupled to said first error generating element at the time that said given training signal is coupled to said first lattice stage through said data transmission channel;
• each of said error generating elements having a first and a second input and comprising means for generating an error quantity which represents the difference between its first and second inputs, the first input to a given error generating element comprising the output of one of said lattice stages, the second input to the given error generating element comprising the error quantity generated by the error generating element which immediately precedes the given error generating element in said succession;
• component adjust means coupled to respective components of said lattice stages and receiving each of said error quantities, said component adjust means comprising means for adjusting said respective components to diminish the error quantity of a given one of said error generating elements to within a prespecified error limit;
• a summation means for providing the sum of all of the lattice stage outputs which comprise said first inputs, said sum comprising the output of said equalizer apparatus;
• and
• switching means for coupling said equalizer apparatus output to said first error generating element, as a first input, at the conclusion of said sequence of training signals.