| 摘要 |
PURPOSE:To detect the deviation of an erasing beam from a track and to prevent erroneous erasure and erroneous recording from occurring by identifying a mark signal provided just behind a sector identifier, by providing an address reproduction circuit, and an M1 gate and an M2 gate generation circuits, etc. CONSTITUTION:In an optical disk using a sector format in which the mark signals M1 and M2 representing the track addresses just behind a sector identifier ID, the address reproduction circuit 1 inputs a recording and reproducing optical beam reproducing signal 100, and outputs an address detecting signal 103. The signal 103 is added on the M1 gate generation circuit 2 and the M2 gate generation circuit 3, and an M1 gate signal 104 and an M2 gate signal 105 are generated. Next, the signals 104 and 105 separate the signals M1 and M2 of an erasing optical beam reproducing signal 101 in a time manner, and detects whether the erasing beam exists on an even track or an odd track. Thus, by identifying the signals M1 and M2 with the timing of the M1 and M2 gate signals generated by the signal 103, it is possible to perform the detection of the deviation of the erasing beam from the track and to prevent the erroneous erasure and the erroneous recording from occurring.
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