Patent ID: 7061848

Claim:
A data reproduction apparatus for detecting data based on partial response maximum likelihood (PRML), the apparatus comprising: an equalizer comprising a digital filter; a level error detector which extracts a level of an output value of the equalizer based on a reference level set in the data detector, and which detects a level error between the level of the output value and a predetermined reference value; and a coefficient adapter which adapts filter coefficients of the equalizer such that a difference between the level error and a target level error is minimized, wherein: the error detector determines the reference value to correspond to a zero level, a positive middle level, a negative middle level, a positive maximum level or a negative maximum level, which are classified depending on the partial response (PR) type of the data detector, based on comparing first sampling data with successive sampling data, and detects the level of the output value of the equalizer, and outputs a level error corresponding to a difference between the detected level and the determined reference value.