Abstract: An equalizer and an equalization method usable in a high definition television (HDTV) are provided. The equalizer may receive an input signal including a data signal and a training sequence and may compensate for distortion of the input signal in a high definition television. The equalizer may include an input signal reuse unit, a filter unit, and an error calculation unit. The error calculation unit may receive an equalizer output signal, may estimate the equalizer output signal at an estimate value, may generate the estimate value as a decision value, and may output a difference between the equalizer output signal and the decision value as the error signal.