Method and apparatus for filtering read signal to three or more cutoff frequencies with two or more bits control line throughout three or more consecutive periods

摘要

An optical disk drive apparatus is provided has a reading section which reads the reflection of a laser beam from a disk to produce a read signal, a filter section which filters the read signal with the use of three or more different cutoff frequencies upon receiving a control signal from a two or more bits control line, a reproducing section which playbacks the read signal filtered by the filter, and a control section which provides the filter with the control signal along the two or more bits control line so that the filtering action with the three or more different cutoff frequencies of the filter is carried out throughout three or more consecutive periods respectively.