| 摘要 |
PURPOSE:To obtain an inexpensive and stable off-track state detector which is easily made small-sized and is independent of the rotation period of a disk, by detecting the damage of the disk by an asynchronous logic circuit which is independent of the rotation period of the disk and does not require passive parts such as a capacitor. CONSTITUTION:A pulse converting means 103 and a state transition discriminating means 104 consist of asynchronous logics, and time elements which control their logical states are only gate delay times of a NOR circuit, a buffer, an inverter, etc., constituting them and are independent of the period of an input signal (a). Consequently, an off-track position of a reproducing head 2 is detected faithfully independently of the rotation period of the disk. Since the detector consists of an asynchronous logic circuit, passive parts such as a capacitor are not required to make the detector inexpensive and small-sized easily.
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