Patent ID: 8654620
Filing Date: 2014-02-18
Classification: G11B

Abstract:
1. An evaluation method, comprising the steps of: fitting a relation between write powers Pw[m] (m being an integer) of a plurality of kinds and a modulation M[m] obtained from a reproduction signal amplitude of a signal subjected to trial writing by a modulation characteristic formula M=Masy×(1−(Pint−Pasy)/(Pw−Pasy)) having an asymptotic modulation Masy, a write power intercept Pint, and an asymptotic write power Pasy as parameters to determine Masy_opt as an optimal value of the asymptotic modulation, Pint_opt as a optimal value of the write power intercept, and Pasy_opt as an optimal value of the asymptotic write power so as to minimize S: calculating a square of a correlation coefficient r between M (Pw[m]) obtained by substituting the Pw[m] into the modulation characteristic formula using the Masy_opt, the Pint_opt, and the Pasy_opt and the modulation M[m] obtained from the trial writing; and evaluating whether or not the relation between the write powers Pw[m] and the modulation M[m] is appropriate for write power adjustment with use of the square of a correlation coefficient r and a predetermined value.