PURPOSE: To perform overwrite at high speed by irradiating a part where a recording magnetic domain is formed by pulse light with large energy and the part where no recording magnetic domain is formed by the pulse light with small energy, and detecting deviation between a recorded magnetic domain and timing information.
CONSTITUTION: A pulse with laser output of 15mw and pulse width of 50nsec as a long pulse and the pulse with pulse output of 15mw and pulse width of 20nsec as a short pulse are prepared based on the fact that the recording magnetic domain remains after the irradiation of long pulse light and to recording magnetic domain remains after the irradiation of short pulse light. Data recording on a disk 1 is performed by controlling the laser power and the pulse width of a semiconductor laser 3 by a laser driving circuit 4. Next, a signal is read out from the magnetic domain on which a recording timing deviation detecting pattern 33 is formed just before performing the overwrite, and the deviation of a recording timing is detected by a phase deviation detection circuit 51. The deviation is inputted to a quantity storage circuit 52, and a recording correction circuit 28 is controlled by the output of a correction quantity arithmetic circuit 53, then, a clock 29 for recording data is generated. In such a way, it is possible to realize the overwrite accurately.
| JPS59207408 | RECORDING AND REPRODUCING METHOD |
| JPS59152527 | INFORMATION ERASING METHOD |
| JP3128026 | COIL DRIVING CIRCUIT |
OTA NORIO
SUZUKI YOSHIO
TAKAHASHI MASAHIKO
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