| 摘要 |
PROBLEM TO BE SOLVED: To suppress a poor influence due to a tangential tilt by eliminating the poor influence of a side lobe due to an electrical processing where characteristics for reducing the strength of the other side lobe when that of one side lobe increases in the tangential tilt that is generated in an actual drive. SOLUTION: For example, in a combination where the product (or sum) of equalization coefficients k11 and k12 in a waveform equalization circuit 15 with three taps becomes constant, the modification setting of the equalization coefficients k11 and k12 is performed by an equalization coefficient setting circuit 22, thus optimizing the equalization coefficients k11 and k12, thus eliminating the poor influence of a tangential tilt due to the combination of the optimized equalization coefficients k11 and k12 even if the biasing of the optical disk surface strength distribution of a main spot due to the tangential tilt or that of the strength distribution of the side lob occurs. |
