| 摘要 |
PURPOSE:To similarly approximate the recording densities at the inner and outer peripheral surfaces of a disk by dividing the frequency input to a speed controller to control to switch the speed of a motor into a plurality of stages. CONSTITUTION:An oscillating frequency in response to the rotating speed is induced by a signal generator 11 by the rotation of the rotor of a motor 12, and the signal of the frequency is input to a speed controller 18 through a frequency divider 28. The controller 18 generates a voltage 20 proportional to the input frequency. This voltage 20 is initialized by the time constant of the variable resistor 22 of a time constant circuit 19, a resistor 23 and an capacitor 21. When the magnetic recording position of a floppy disk 26 is altered from the inner to the outer peripheral surfaces, the projection 33 of an arm 32 closes a time constant changeover switch 24 to shortcircuit a frequency divider 28 inserted between an amplifier 17 and the controller 18. Thus, the rotation of the motor 12 is doubled. |
