| 摘要 |
PURPOSE:To simplify a signal detecting system, and to prevent a data from being omitted, by converting a detecting signal in which magnetizing information and phase information is mixed, to a binary-coding signal, by each separate threshold, and thereafter, taking OR, and synthesizing both the signals. CONSTITUTION:An optical beam is irradiated from a semiconductor laser 3 to a recording medium 1 having magnetizing information which is recorded by a heat magnetic effect and phase information which is recorded by an uneven pit, and its reflected light is detected by a photodetector 9 through an optical analyzer 8. In this photomagnetic information system, the detecting signal in which the magnetizing information and the phase information is mixed is converted to a binary-coding logical signal by a comparator 1 and a comparator 2 by each separate threshold, and thereafter, both the signals are synthesized by taking OR by an OR gate 13. In this case, a rotational angle of the analyzer 8 is set in advance so that S/N of a reproducing signal of the magnetizing information becomes maximu, and a signal modulation degree depending on a depth of the uneven pit of the phase information becomes maximum. In this way, a signal detecting system is simplified and a data omission can be prevented.
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