Multiple stage adaptive equalizer

An apparatus including an adaptive equalizer with multiple, serially coupled adaptive filter stages for providing a signal path having a signal gain magnitude which selectively increases with signal frequency, comprising:

• a plurality of adaptive filter circuits, serially coupled to one another, configured to receive a plurality of adaptation control signals and in accordance therewith receive, filter and magnitude weight an input signal in a form of an incoming data signal corresponding to a plurality of data and in accordance therewith provide an output signal in a form of an equalized data signal corresponding to said plurality of data, wherein
• a frequency domain ratio of said equalized data signal to said incoming data signal represents an equalization transfer function with a signal gain magnitude which selectively increases with signal frequency,
• each one of said plurality of adaptive filter circuits is configured to receive a respective one of said plurality of adaptation control signals and in accordance therewith receive, filter and magnitude weight a respective one of a plurality of input data signals corresponding to said plurality of data and in accordance therewith provide a corresponding, respective one of a plurality of output data signals corresponding to said plurality of data,
• a frequency domain ratio of each respective one of said plurality of output data signals to said corresponding, respective one of said plurality of input data signals represents a respective one of a plurality of adaptive filter transfer functions, and
• a product of said adaptive filter transfer functions equals said equalization transfer function;
• and
• an equalizer controller, coupled to said plurality of adaptive filter circuits, configured to receive an equalization control signal and in accordance therewith provide said plurality of adaptation control signals, wherein
• said equalization control signal has a magnitude which corresponds to said equalization transfer function, and
• each one of said plurality of adaptation control signals has a magnitude which corresponds to a respective one of said plurality of adaptive filter transfer functions.

A method of adaptively equalizing a data signal received via a communications path having a signal loss magnitude which increases with signal frequency, comprising the steps of:

• receiving a first input signal in a form of an input data signal corresponding to a plurality of data via a communications path which includes a plurality of serially connected, respective communications path sections, wherein said communications path has associated therewith a communications path transfer function with a signal loss magnitude which increases with signal frequency, said plurality of serially connected, respective communications path sections has associated therewith a plurality of corresponding, respective communications path section transfer functions, and a product of said corresponding, respective communications path section transfer functions equals said communications path transfer function;
• receiving a first adaptation control signal and in accordance therewith filtering and magnitude weighting said input data signal and in accordance therewith generating a first output signal in a form of a first equalized data signal corresponding to said plurality of data, wherein a frequency domain ratio of said first equalized data signal to said input data signal represents a first adaptive filter transfer function and said first adaptive filter transfer function is an approximate inverse of a first one of said plurality of corresponding, respective communications path section transfer functions;
• receiving a second adaptation control signal and in accordance therewith filtering and magnitude weighting a second input signal in a form of said first equalized data signal and in accordance therewith generating a second output signal in a form of a second equalized data signal corresponding to said plurality of data, wherein a frequency domain ratio of said second equalized data signal to said first equalized data signal represents a second adaptive filter transfer function and said second adaptive filter transfer function is an approximate inverse of a second one of said plurality of corresponding, respective communications path section transfer functions;
• and
• receiving an equalization control signal and in accordance therewith generating said first and second adaptation control signals, wherein said equalization control signal has a magnitude which corresponds to said communications path transfer function, said first adaptation control signal has a magnitude which corresponds to said first one of said plurality of corresponding, respective communications path section transfer functions, and said second adaptation control signal has a magnitude which corresponds to said second one of said plurality of corresponding, respective communications path section transfer functions.

A method of adaptively equalizing a data signal with a signal gain magnitude which selectively increases with signal frequency, comprising the steps of:

• receiving a plurality of adaptation control signals and in accordance therewith receiving and successively performing filtering and magnitude weighting operations upon an input signal in a form of an incoming data signal corresponding to a plurality of data and in accordance therewith generating an output signal in a form of an equalized data signal corresponding to said plurality of data, wherein a frequency domain ratio of said equalized data signal to said incoming data signal represents an equalization transfer function with a signal gain magnitude which selectively increases with signal frequency, and wherein each one of said filtering and magnitude weighting operations includes the step of receiving a respective one of said plurality of adaptation control signals and in accordance therewith receiving, filtering and magnitude weighting a respective one of a plurality of input data signals corresponding to said plurality of data and in accordance therewith generating a corresponding, respective one of a plurality of output data signals corresponding to said plurality of data, and further wherein a frequency domain ratio of each respective one of said plurality of output signals to said corresponding, respective one of said plurality of input signals represents a respective one of a plurality of adaptive filter transfer functions, and a product of said adaptive filter transfer functions equals said equalization transfer function;
• and
• receiving an equalization control signal and in accordance therewith generating said plurality of adaptation control signals, wherein said equalization control signal has a magnitude which corresponds to said equalization transfer function, and each one of said plurality of adaptation control signals has a magnitude which corresponds to a respective one of said plurality of adaptive filter transfer functions.