Patent ID: 6570940
Filing Date: 2003-05-27
Classification: G11B,H03M

Abstract:
An information reproducing apparatus for reproducing data on a recording medium corresponding to Viterbi decoding method, data thereon having been recorded with an RLL code, wherein said recording medium has a plurality of areas including an address area and a recordable area each having different reproduced signal qualities, the apparatus comprising:Viterbi decoding means for calculating a branch metric in each of a plurality of statuses with an input reproduced signal and an amplitude reference value and for selecting a maximum likelihood status transition with an added value of the calculated branch metric and a past path metric; amplitude reference value adapting means for updating the amplitude reference value, depending upon which of said address area or said recordable area said input reproduced signal is reproduced from, with the selected maximum likelihood status transition and the input reproduced signal corresponding to each of a plurality of clock pulses; and initial value setting means for setting an initial value of the amplitude reference value corresponding to a plurality of reproducing operations.