| 摘要 |
PURPOSE:To improve the accuracy of head position follow-up control by detecting directly a shift from a signal track by a recording/reproducing magnetic head to control a complete closed loop servo system. CONSTITUTION:At the recording time, switches SW1, SW2 are turned to a head position regulating mode by switching signals and position regulating signals are inputted to a differential amplifier 27 through terminals 26. A control motor 28 to be moved in the X direction is actuated and W/R magnetic heads are located on a prescribed position. A recording signal from an input terminal 30 is inputted to the W/R heads 20, 21 through recording amplifiers 31, 32. The gain of the driving amplifiers 31, 32 is controlled and a signal track 23a having the same recording level is recorded on a magnetic disc 22. At the reproducing time, the switches SW1, SW2 are switched to a magnetic head servo control mode, the branches of reproduced and amplified signals from amplifiers 33, 34 are also supplied to a differential amplifier 27 and the head position control motor 28 can be actuated so that the difference of both the reproduced signals is goes to ''0''. |
