| 摘要 |
PURPOSE:To improve the accuracy of head positioning by writing in advance a position error signal (servo signal) to a magnetic disc, allowing the magnetic head to reproduce the position error signal and driving minutely a stepping motor by the position error. CONSTITUTION:A signal read by the magnetic head 11 is inputted to a position signal detecting section 14 via a head amplifier 12 and a filter 13. The level of the signal is detected by a synchronizing signal detecting circuit 15, a synchronizing signal is inputted to a timing signal generating circuit 16, two timing pulses delayed by different times from the synchronizing signal are generated, inputted to sample and hold circuits 17, 18, where they are sampled and held, a position signal is fed to a differential amplifier 19 and the position error signal is outputted. The position error signal is fed to an actuator drive section comprising an adder circuit 22, register 23, memories 24, 25, DA converters 26, 27 and drivers 28, 29 via a phase compensating circuit 20 and an AD converter 21 to drive a stepping motor 30 in a direction where the position error signal is decreased. |
