| 摘要 |
PURPOSE:To allow either face of a magnetic disk to reproduce information data by providing a means detecting the positive and negative peak positions of a reproduced signal and selecting either one of detected outputs based on a control signal. CONSTITUTION:The output signal 13 of a differentiation circuit 4 is converted into a digital signal in a detection circuit 5, and a signal 14 detecting the positive peak position of the reproduced signal 12 is outputted at a circuit part constructed of an inverter 6, a resistance 7, a capacitor 8 and a NOR gate 9. A positive peak position detection signal 16 is outputted and led to the one input of a switching circuit 30. The output signal 26 of a differentiation circuit 18 is converted into a digital signal in a zero cross detection circuit 19, and a signal 27 detecting the negative peak position of the reproduced signal 12 is outputted at a circuit part constructed of an inverter 20, a resistance 21, a capacitor 22 and an AND gate 23. A negative peak position detection signal 29 is outputted and led to the other input of the switching circuit 30. According to the control signal 32, signals are switched corresponding to each face, and an output signal 31 can be obtained.
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