Method and apparatus for channel equalization

A method for equalizing a signal comprising:

• receiving a signal transmitted through a communication channel;
• performing a first equalization process on the signal utilizing a first equalizer having maximum phase coefficients values;
• and
• performing a second equalization process on the signal utilizing a second equalizer having second equalizer coefficient values;
• wherein the first equalization process and the second equalization process reduce the effects of transmission through the channel.

A system for channel equalization comprising:

• a first filter configured to utilize one or more first filter coefficients, the first filter comprising maximum phase filter;
• a second filter having two or more second filter coefficients with at least one of the two or more second filter coefficients forced to a predetermined value;
• and
• a precode filter having one or more precode filter coefficients, the precode filter comprising a minimum phase filter;
• wherein the first filter and the second filter are located in a receiver and the precode filter is located in a transmitter.

A system for exchanging data between a first location and a second location, the system comprising:

• a first transceiver comprising:
• a data source interface configured to receive data from a data source;
• a precode filter configured to equalize the data to at least partially account for transmission through a channel;
• a digital to analog converter configured to convert the data to a first analog signal;
• a line driver configured to adjust the power of the first analog signal for transmission over a channel;
• a receiver configured to receive data from a second transceiver;
• a second transceiver comprising:
• an amplifier configured to receive a second analog signal from the channel, the second analog signal comprising a distorted version of the first analog signal;
• an analog to digital converter configured to convert the second analog signal to data;
• a first filter configured to process the data to at least partially reverse the effects of transmission through the channel;
• a second filter configured to process the data to at least partially reverse the effects of transmission through the channel;
• a decision device configured to quantize portions of the data into two or more distinct values;
• a transmitter configured to transmit precode filter coefficient data to the precode filter in the first transceiver.

A computer program product comprising a computer useable medium having computer program logic recorded thereon for calculating equalizer coefficients, comprising:

• computer program code logic configured to initiate a training sequence;
• computer program code logic configured to train coefficients of feedforward filter as a mixed phase filter;
• computer program code logic configured to train coefficients of a feedback filter, wherein at least one of the coefficients of the feedback filter is set to zero;
• computer program code logic configured to process the coefficients of the feedforward filter to calculate minimum phase coefficients and maximum phase coefficients;
• computer program code logic configured to establish the feedforward coefficients based on the maximum phase coefficients;
• and computer program code logic configured to establish precoder coefficients based on the minimum phase coefficients.

A system for processing a signal to compensate for transmission through a communication channel comprising:

• means for receiving a signal;
• means for amplifying the signal;
• means for filtering the signal based on a first coefficient set to create a first filtered signal;
• means for combining the first filtered signal with a feedback signal;
• means for decision processing the signal to output a predetermined value wherein the predetermined value is selected from a group of two or more predetermined values;
• and
• means for filtering the predetermined value based on a second coefficient set to create a feedback signal;
• wherein the first coefficient set comprises coefficients based on maximum phase coefficients arrived at during a training operation.