Coefficient update circuit, adaptive equalizer including the coefficient update circuit, and coefficient update method of the adaptive equalizer

An adaptive equalizer comprising:

• a delay circuit, which generates a plurality of delayed input signals by delaying an input signal for a predetermined amount of time, the delayed input signals being divided into a group of first delayed input signals and a group of second delayed input signals;
• a coefficient multiplier circuit, which multiplies the first delayed input signals with respective filter coefficients and outputs the multiplication results;
• an adder circuit, which generates an output signal by adding the multiplication results;
• an error generation circuit, which generates an error signal that is a difference between the output signal and a desired signal level;
• and
• a coefficient update circuit, which detects a level of the error signal and levels of the second delayed input signals and generates current values of the filter coefficients by updating previous values of the filter coefficients based on update values designated by the detected level of the error signal and the detected levels of the second delayed input signals.

An adaptive equalizer comprising:

• a filter, which multiplies a plurality of first delayed input signals with respective filter coefficients, outputs the multiplication results, and generates an output signal by adding the multiplication results, the first delayed input signals being generated by delaying an input signal for a predetermined amount of time;
• an error generation circuit, which generates an error signal that is a difference between the level of the output signal and a desired signal level;
• and
• a coefficient update circuit, which detects a level of the error signal and levels of a plurality of second delayed input signals and generates current values of the filter coefficients by updating previous values of the filter coefficients based on update values designated by the detected level of the error signal and the detected levels of the second delayed input signals, the second delayed input signals being generated by delaying the input signal for a predetermined amount of time.

A coefficient update method of an adaptive equalizer, comprising

• detecting a level of an error signal that is a difference between a level of an output signal of the adaptive equalizer and a desired signal level;
• and
• detecting levels of a plurality of delayed input signals generated by delaying an input signal of the adaptive equalizer for a predetermined amount of time;
• selecting update values from an update value table with reference to the detected level of the error signal and the detected levels of the delayed input signals;
• and
• adding the selected update values to previous values of filter coefficients and outputting the addition results as current values of the filter coefficients,
• wherein the current filter coefficient values are provided to a filter included in the adaptive equalizer.