Patent ID: 6301201
Filing Date: 2001-10-09
Classification: G11B

Abstract:
A reading apparatus for an optical recording medium comprising:track counting means for counting a number of signals crossing a slice level as a number of tracks, wherein the signals are an added signal or a subtracted signal of a top envelope and a bottom envelope of an RF signal read out from a signal recording area of the optical recording medium while image searching; andslice level calculating means for detecting an upper limit level and a lower limit level of the added signal or the subtracted signal obtained by scanning a circumference direction of the signal recording area, for holding the upper limit level and the lower limit level of the added signal or the subtracted signal detected, and for calculating an average of the upper limit level and the lower limit level as the slice level, wherein said slice level calculating means are characterized by supplying said upper limit level of the added signal or the subtracted signal to said track counting means as an upper limit of a slice level and determining said upper limit level by measuring said upper limit level in response to a result of counting by said track counting means, and further characterized by supplying said lower limit level of the added signal or the subtracted signal to said track counting means as a lower limit of a slice level and determining said lower limit level by measuring said lower limit level in response to a result of counting by said track counting means and calculating said slice level.