Patent ID: 7295502
Filing Date: 2007-11-13
Classification: G11B

Abstract:
1. An optical disk apparatus that records and reproduces information by irradiating an optical disk medium with an optical laser pulse, and performs trial writing that optimizes the laser pulse irradiating condition, comprising: a means of recording a predetermined trial writing pattern in a predetermined region of the optical disk medium changing the laser beam irradiating condition; a means of reproducing the predetermined data, and obtaining a first reproducing signal; an analog filter that equalizes the first reproducing signal and obtains a second reproducing signal; an A/D converter that digitalizes the second reproducing signal and obtains a third reproducing signal; a FIR filter that equalizes the third reproducing signal and obtains a fourth reproducing signal; a PRML circuit that binarizes the fourth reproducing signal and obtains a binarized data row; an edge level detector that uses the third reproducing signal as input and detects a signal level of an edge; a logical pulse generator that judges that the signal level of the edge is outside the range of a predetermined value and generates a logical pulse; and a means of judging a data pattern in accordance with the preceding space length, the preceding mark length, and the succeeding space length from the binary data row, counting the logical pulses in units of the data patterns and generating a logical pulse table, wherein the laser pulse irradiating condition is decided using a count value in the logical pulse table.