| 摘要 |
PURPOSE:To eliminate the need to match the levels of two signals and to shorten a switching time by synthesizing a signal of two signals detected by different photodetectors in a digital signal state. CONSTITUTION:A photomagnetic signal detection system consists of an analyzer 10, a lens 11, and photodetector 12 and the slight rotation of a plane of polarization is converted by the analyzer 10 into variation in the quantity of light, which is detected by a photodetector 12. A servo signal and header signal detection system consists of an optical detection system 13 and a photodetector 14. A photomagnetic signal is amplified by an amplifier 15 and converted into an analog signal, which is digitized by a digitizing circuit 16. A header signal detected by another detector 14 is amplified by an amplifier 17 and a converted into an analog signal, which is digitized by a digitizing circuit 18. Those are put together and a timing signal for removing a header signal part from the photomagnetic signal is generated by passing the header signal through a timing generating circuit 19.
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